I_1 DISSERTATION ON A STUDY OF THE ENVIRONMENTAL PROBLEMS IN AND INDUSTRY

Submitted in partial fulfillment of the requirements for the award of the Degree of

MASTER OF TECHNOLOGY IN PULP AND PAPER

m

DEEPAK BHARDWAJ

, ._ }36 3 s .*L;

DEPARTMENT OF PAPER TECHNOLOGY INDIAN INSTITUTE OF TECHNOLOGY, ROORKEE SAHARANPUR CAMPUS, SAHARANPUR - 247001 JUNE - 2007

- ACKNOWELEDGEMENT

I take this opportunity to express my deep sense of gratitude,. obligation and indebtedness to my esteemed advisor Dr. C.H Tyagi Associate Professor, Dr. Dharmdutt Associate Professor in Department of Paper Technology (DPT) Saharanpur Campus of IIT. Roorkee for thier creative guidance, keen interest, valuable suggestions, constructive criticism and constant encouragement during the preparation of this manuscript.

I am thankful to all the staff of DPT Saharanpur Campus of IIT Roorkee and also thankful. to all the staff of Machine House 1 department of , BILT Yamuna Nagar unit for their kind cooperation.

Lastly, I am thankful to my family members and friends for constant -encouragement, which has , led this piece of work to its successful completion.

(DEEPAK BHARDWAJ) Date: l 1 1 61 0 7

M.Tech. (Pulp and Paper) Place: EnI. No. 045305 Candidate's Declaration

I hereby certify that work which is being presented in this report entitled " A study of the environmental problems in " in partial fulfillment of the requirements for the award of the degree of Master Of Technology and submitted in the Department of Paper Technology of IIT Roorkee, is an authentic record of my own work carried out under the supervision Dr. C. H. Tyagi, Associate Professor and Dr. Dhram Dutt , Associate Proffesor in the Department of Paper Technology. Date- 1 R I o7 Place- Sharanpur (Deepak Bhardwaj) This is to certify that the above statement made by the candidate is correct to the best of my knowledge.

(Dr.C.H.Tyagi) (Dr.Dharm Dutt)

Proffesor Associate Proffesor Deptt. Of Paper Tech. I.I.T.R, SAHARANPUR CAMPUS SAHARANPUR-247001 Index Contents Page no

Chapter 1 Introduction 1 Chapter 2 Pulp and paper industry and environmental impact 4 1.0 Environmental issues 4 2.0 Deforestation and ecological imbalance 5 3.0 Deforestation, logging activities and environment 5 4.0 Pollution aspectsp 7 4.1 Air pollutants 7 4.2 Land and water pollution 8 Chapter 3 Pollutants from pulp and paper mills in world, monitoring and measurement techniques of pollutants 10 Pollution control 19 Sampling of effluent 21 CREP for pulp and paper industry 24 National environmental standard in pulp and paper industry 25 Chapter 4 Magnitude of pollution from pulp and paper 27 1.0 Manufacture of paper 27 2.0 Sources of pollutants 28 2.1.1 Volume and pollution characteristics 29 2.2.2 Toxic component in pulp and waste waterao 29 Chapter 5 nvironmental pollution from pulp, paper and straw board ~nc~Sty i sin India 40 1.0 Environmental pollution problems 40 2.0 Large pulp and paper factory, 200 MT/day capacity 41 3.0 The Rayon grade pulp factory 46 4.0 Medium size factory 50 T/day capacity 49 Environmental impact of pulp and paper factories 52 Pollution control practices 53 Development and research needs 54

Chapter 6 Performance of waste treatment plant at Orient paper mill, Amalai (A Cau- 57 1.0 Introduction 57 2.0 Development of treatment facilities 59 3.0 Pilot plant studies and their significance 60 4.0 Intersize lagoon (ISL) studies and their significance 60 5.0 Aerated lagoon pilot plant studies and their significance 61 6.0 Research project on Grade II effluent 61 7.0 Grade III effluent 64 8.0 Performance of treatment units 66 9.0 Cost 70

Chapter 7 The application of Rapson — Reeve closed cycle concept at Great Lake Forest Products, Thunder Bay, Ontario 71 1.0 Description of the concept 71 2.0 Mill design 71 3.0 Pulping and bleaching operation 73 4.0 Mill effluent characteristics 75 5.0 Cost of the closed cycle system 76 Chapter 8 Environmental magnitude in India 1.0 Historical prospective 2.0 Environmental legislsative network 3.0 Environmental legislation in India 4.0 Environmental legislation for industry and business 5.0 Environmental appraisal procedural frame work for establishing and operating an industrial unit 95 6.0 Environmental Management System 96 7.0 List of projects requiring environmental clearance from the Central Government 8.0 Industry specific standards environment (protection) rules, 1986 Chapter 9 Environmental management at Ballarpur Industries Ltd, Unit- Shree Gopal 101 Introduction 101 Environmental measures at plant 103 Waste water management 106 Lime mud management 111 Air pollution control measures 113 Conclusion 115 Chapter 10 Towards zero-effluent pulp and paper production 116 Executive summary 116 Introduction 118 Pulp production processes 121 Water use 129 Bleaching agents and processes for chemical pulps 131 Pollution control measures 142 Effects of process modifications on organochlorine production 149 Chlorine and chlorine dioxide linkage 154 Biological impacts of mill discharges — recent research 156 Endocrine disruption and pulp and paper mills 160 Totally effluent free processes — closing the bleach circuits 162 G kc~ p 1 s a.A,ot. ~~cLy►.,z►, o~ie~•~ 1 S 171 CT~~erG~x 1~t CHAPTER-1

INTRODUCTION

Pollution control is vital for a nation as the quality of life is linked with the quality of environment. In country like ours with a developing economy, can the objectives be achieved by only passing legislations and fixing broad and general standards. The problem is acute and complex for a vast country like India, each mill having its own problems and limitations. It has been emphasized that the mode of treatment and disposal of an effluent from an ' individual unit should specially be chosen taking in to consideration all factors like location, process, economical conditions, land availability, the condition of receiving water source and other possible modes like for those needed for agricultural use etc., rather than the insistence on a particular quality of an effluent. Pollution control regulations are a right step in the direction to regulate industry to meet their obligations towards society. A clean and healthy environment is vital for the survival and welfare of the human being. In view of the implementation being capital intensive, it is however ensured that the growth of the industry is not hampered and iS +got' economy affected adversely. The laying down of regulations and formulation of the standards is essential but their true implementation has to be practical and in a phased way taking into consideration the relevant factors involved. It is due to this that several countries are either not keen or very slow in following religiously anti pollution regulations. In spite of many countries having anti pollution legislation in some form or the other, only few made progress in translating their legislation effectively. Industrial projects have profound influence on society and environment, resulting in benefits, risks and hazards. They bring in their wake the concomitant ills of environmental pollution, depletion of resources, over crowding, effects on human health, desecration of forests and aesthetic nuisance. Adverse impact on environment results because of indiscriminate and unregulated exploitation of both renewable and nonrenewable resources in the environment, and the use and abuse of environment as a sink for dumping the waste products of developmental activities. India is on the threshold of development. During this critical period, an environmentally compatible development need be evolved. An analysis and assessment of the environmental impacts arising out of a development project provide the necessary guide lines for siting, systems modification if any, during construction and operational phase, choosing the degree and type of control for pollutant emissions and environmental management. Paper industry in India is one of the oldest core sector industries serving the nation by producing different quality of and meeting the demands from all corners of the society. The socio economic importance of paper in the national development is very high as it is directly related to industrial and economic growth of the. country. Presently, the total installed capacity of paper manufacturing in the country is about 6.40 million tones per annum while the capacity utilization is 70% on an average producing about 4.25 million tones of paper per annum. The major raw material used in paper making are wood (bamboo, eucalyptus), agro based raw material (bagasse, white straw, rice straw ) and waste paper. The wood based pulp and paper mills shares 37% of the total capacity while agro-based category contributes 33% and rest are waste paper based. Industrial development and environment are linked to each other. It is apprehended that the environment is adversely affected the growth of industry. This relation in today's context seems to be justified while visualizing the effect of waste discharges in the surroundings and its effect on ecology. Development is a need of the society but at the cost of environment may not be acceptable. There has to a sustainable development where environmental aspects have also to be considered with growth of the industries. Paper industry fortunately is based on renewable sources of raw materials and creates a product which is biodegradable. The paper manufacturing cycle is sustainable. Although, the cycle for wood based raw materials (bamboo, eucalyptus) is lengthy but the cycle for agro-based raw materials is renewable every year and is generated in abundance from the agricultural fields. The wastepaper is also recyclable for making paper again. The pollution problem from pulp and paper industry need to be addressed carefully. The pollution problem in wood based pulp and paper industries agro-based pulp and paper industries are different in nature. The wood based pulp and paper industry have better sustainable approach while the most agro-based pulp and paper mills lacks in this respect. The better environmental practices adopted by wood based (large) mills are mainly on account of financial capability, better infrastructure, skilled man power, R&D support and better management practices. Most of the agro-based pulp & paper mills (small) are

2 literally insensitive towards addressing environmental issues due to obsolete equipments, uyv Ski.Ued- an power, poorly managed approach and lack of willingness which leads to damaging effect on environment. Pulp and paper industry is one of the major polluting industries and such categorized by CPCB in 17 categories of highly polluting industry. The problem of environmental damage is quite pre-dominant in pulp & paper industry.

3 CHAPTER -2

PULP AND PAPER INDUSTRY AND ENVIRONMENTAL IMPACT

1.0 ENVIRONMENTAL ISSUES Pulp and paper industry draws its resources, mainly from wood, a natural biomass and to some extent from non wood resources, which are converted to cellulose, the basic constituent of paper. The paper industry consumes various cellulosic materials namely bamboo, eucalyptus, sabai grass, begasse, salai wood, coniferous wood, waste paper, agricultural waste and imported pulp. The process of making pulp and paper requires large amount of water and energy. In India, the activities arising out of raw material utilization and manufacturing process bring rise to ecological and environmental problems, which can be classified under three aspects: i) depletion of renewable wood and non wood resources contributing to deforestation, ii) increased resort to monoculture eucalyptus plantations with consequent ecological imbalance of tropical evergreen forests, in pollution of environment, waste waters and solid wastes leading to land and water pollution, air and odour emissions leading to air pollution. Not only the conventional direct polluting effects on land, water and air caused immediately by the activities within the factory, but equally the important aspect of ecological impact caused by the activities in the forest supplying fibrous raw material, should also be considered. The forest potential in India is given below — Total forests : 75 mill. Hectares Percentage of forest to land : 22.8 Per capita forest area 0.13 hectare as compared to world average of 1.08 hectares. An average of 4.1 million people are engaged in forestry activities. Revenue from forests : Rs. 2,983 million Forest revenue as percentage of national revenue: 2:3

4 2.0 DEFORESTATION AND ECOLOGICAL IMBALANCE: In view of the rapidly rising demand of paper and pulp products, it is unlikely that the production from the natural forests even after they are fully tapped, will be able to meet the requirements of the mills. Anticipating this, the forest departments of various states in India have already started creating plantations of fast growing species, particularly eucalyptus, a short fiber wood and of bamboos and conifers which have long fiber. The demand of paper product as grown rapidly over the past 20 years, and expected to grow at more than five percent over the next few years, thus making up an ever increasing proportional of industrial wood use. The growing consumption of all types and uses of wood is putting pressure on forests, and it is clearly in the interest of paper and pulp industry to ensure that it has continued access to renewable resources. Proper forest management is, there-fore, of critical importance. With increased growth of demand and pressures on landuse, it is debatable whether the industry can sustain increased production. There-fore the reasons for concern, in as much filling is far outstripping reforestation. The Tropics is one of the worlds richest environments with regard to species diversity, and yet it is the most vulnerable. The maintenance of tropical forests is an essential requirement for stabilizing climate and soil structure. An adverse environment impact can happen on agriculture, water course and other human enterprises covering a larger area than that occupied by the forests, namely, soil erosion, flash floods, , removal of top soil-depletion of firewood, depletion of ground water regime, change in traditional occupation of humans living nearby or drawing sustenance from forests. When forests are exploited, the cultivators cash in on agriculture. The agriculture that follows is often unsustainable in the long term, resulting in ecological degradation. Felling of a definite quantity of wood in a forest, may trigger a chain reaction of additional areas of forests being falle` h down for transportation, access of human habitation, cultivation etc. 3.0 DEFORESTATION,LOGGING ACTIVITIES AND ENVIRONMENT: In managed forest areas, the main concern will be to preserve basic soil fertility, maintaing a reasonable stable marketable output, minimize undesirable effects in fresh water and marine ecosystems and maintain an aesthetically and socially desirable quality

5 of landscape, including flora, fauna, water and air. Fig shows a simplified model of a forest ecosystem and identification of critical points of intervention by logging. FIGURE SHOWN AS BELOW :------ENERGY CO2 02 ATMOSPHERE HEAT WATER CO2 MINERALS 02 NUTRINETS WATER

FOREST ECOSYSTEM NEIGHBOURING

VEGETATION I ANIMALS ECOSYSTEMS

WATER FAUNA 8 MICROFLORA ~-~

SOIL MATERIAL SOIL - ROOT ZONE V V

WATER NUTRIENTS

LOWER SOIL LAYERS

MAJOR DIRECT IMPACTS OF LOGGING IN ECO-SYSTEM

SECONDARY EFFECTS OF LOGGING IN ECO- SYSTEM

NATURAL ECO-SYSTEM TRANSFERS LOCAL ENVIRONMENT - IMPACT OF LOGGING

.1 4.0 POLLUTION ASPECTS:

4.1 AIR POLLUTANTS

Three major sources of air borne emissions are from liquor preparation, cooking and chemical recovery, both particulates, gases and odour are involved. The air borne wastes from sulphate pulping consists mainly of: 1) Particulates from the: a) Recovery furnace, composed of sodium sulphate and sodium carbonate plus carbon particles. b) Lime klin, composed essentially of lime dust. c) Power plant, composed of flyash, soot or unburned bark, depending on the fuel used. ii) Mists from the: a) Recovery furnace b) Lime kin c) Dissolving tank d) Causticizer e) Digester f) Blow tank iii) Odours and Non —odourous gases from the: a) Recovery furnace, composed essentially of sulphur dioxide and hydrogen sulphide. b) Lime kli, containing smaller quantities of the same two gases. c) Power plant, consisting of sulphur dioxide if the furnace being operated properly. d) Digester relief, containing inorganic and organic sulphur compounds, such as hydrogen sulphide, methyl mercaptan, dimethyl sulphide, and dimethyl disulphide. e) Blow tank, containing the same compounds. f) Turpentine recovery ( not used in India)

7 g) Evaporators, consisting of hydrogen sulphide, methyl mercaptan, dimethyl sulphide, and dimethyl disulphide. Other sources are active, but those mentioned are believed to be the major ones. In terms of volume, the off gases from the recovery furnace make this the major source. Digester relief gases, blow gases, and the off gases from the evaporators represent a considerably smaller volume, but have a potentially higher nuisance value. The effects of fallouts like fly ash, soot, lime, wood particles create aesthetic nuisance and deposition of dust on near by habitation. Vegetation damage may result from sulphurdioxide and fallout of particulates. Smaller particles are carried long way resulting in visibility interference and carry odour to long distance. Paint especially lead based discolouration due to hydrogen sulphide is one of the common complaints. Odours due to sulphur compounds are also caused in the vicinity of pulp mills. Control can be considerd by providing cyclones, precipitators or scrubbers for particulate, and collection and oxidation of blow gases and digester release gases. Odours are in seperable from the process. Odour free operations will depend on the methods for retaining them in the system or converting them to innocuous substance, cost effective technologies are developed. 4.2 LAND AND WATER POLLOUTION: The small paper and board mills in India (up to 30 tonnes per day) consume on an average 220 to 410 m3 of water per tonneof product, and an integrated mill (100 tonnes per day and above) consumes 300 to 425 m3 of water per tonne of product. The pollution load per tonne of product from small units is higher than that of a large mill, where recovery and reuse of chemicals from black liquor is practiced. The problem with the wastewaters is its high BOD, COD and suspended solid content, dark coloration. and relatively high sodium content. Colour and COD in waste waters are the most difficult problems requiring solution by cost effective technology which are not yet available. The practicable methods should aim at providing in plant controls, recovery of chemicals and fibers, segregation of streams, and recycling of treated waste waters wherever feasible. Utilisation of partially treated effluent for farming can be considered, but this requires detailed pre-irrigation studies of soil character, proper choice of cropping and scientific irrigation and environmental management. Normally, irrigation is limited to

LIJ coarse textured soils. Low cost treatment methods have to be evolved for small sized plants ( 20 to 30 tonnes per day capacity). Application of the waste water with or without treatment on land will lead to deleterious effects due to high sodium. Anaerobic lagooning in earthen basins and holding black liquor in earthen lagoons should be discouraged as they result in ground water polloution and odour problems. Another related, aspect is the problem of disposal of solid wastes, especially mud. The quantity of lime sludge produced will be around 1.25 to 1.70 tonnes per tonne of paper on wet basis, while on dry basis, it will be 0.5 tonnes per tonne of paper. At present, these are dumped on follow land. During rains, these are partly washed in to natural water courses or spread on land. Availability of sufficient area of land also poses problem. Cost effective methods to recover lime after silica removal from sludge need be evolved. In order to minimize environmental damage, a systematic environmental impact analysis and assessment should be carried out for site locations.

6 CHAPTER -3

POLLOUTANTS FROM PULP & PAPER MILLS IN WORLD, MONITORING AND MEASUREMENT TECHNIQUES OF POLLUTANTS The pulp and paper industry utilizes various raw materials, such as forest based and non- forest based (agricultural residues, grasses etc.) species. Some of the non forest based are renewable in nature. Such species include baggase, rice straw, wheat straw, jute, hemp etc. For integrated mill the major inputs, outputs and wastes per tonne of paper can be given as : Raw materials (bamboo, wood etc.) 2.75-3.0 t/t, coal 1.5-2.0 t/t, chlorine 150- 200 kg/t, lime 500-600 kg/t, sodium sulphate 125-150 kg/t, talcum powder/chemicals 150-200 kg/t, other chemicals (alum/rosin etc.) 75-200 kg/t — total 5.250-6.250 t/t. To produce pulp and paper out of these raw materials various chemicals are employed. Some materials/chemicals are also being discharged as bye product or as refuse in form of gases, liquids or solids are mostly potential pollutants. From material balance of wood for manufacture of paper by it is observed that about 41.8% of wood is recovered as bleached pulp of the remaining wood , roughly 4.2% ends up as solid waste, 5.25% goes in to waste waters as dissolved organic matter and 2.3% goes as suspend solids in waste water. The potential pollutants from a pulp and paper mill fall in to four principal categories as under: (I)SOLID WASTES: a) Sludges from primary and secondary treatment and causticizing in kraft mill recovery section. b) Solids such as grit bark and other mill wastes. c) Ash from coal fired boilers. The gaseous emissions are released from digesters, chemical recovery furnace, steam boiler, H2S, S02, S03 malodorous gases (like mercaptans, Dimethyl sulphide, Dimethyl Disulphide). The ordor problem in kraft mills is essentially due to reduced Sulpher compounds.

10 (H) WATER EFFLUENTS: a) Suspended solids including bark particles, fiber, pigments, dirt and the like. b) Dissolved colloidal organics like hemicelluloses, sugars, lignin compounds, alcohols, turpentine, sizing agents, adhesives like starch and synthetics which create BOD load. c) Colour bodies, primarily lignin compounds and dyes. d) Dissolved inorganic such as NaOH, Na2SO4, bleach chemicals etc. e) Bleach plant effluents (TOCI, AOX, TODD, BOD, COD etc.). f) Thermal loads. g) Microorganism such as coliform group. h) Toxic chemicals if present. (III) PARTICULATES: a) Fly ash from coal fired power boilers. b) Chemical particles primarily Na and Ca based. c) Char from bark burners. (IV) GASES: a) Inodurous Sulphur gases such as mercaptans and H2S released from various stages in Kraft recovery furnace and lime kiln. b) Bleach plant emissions, Cl2, C102, 03, Chloroform etc. c) Steam since it can be hazardous when visibility is impaired/lime kilns containing particulate matters. d) Other NCG (Co, CO2, Hydrocarbon, H2S, HCI, HF etc.). Emissions rates, kg/tonne pulp from a chemical pulp bleaching are as under: C12,: 0.1-3, C102: 0.1-1 and S02: 0.1-1. The statics of the pollution loads, norms and gravity standard instrumental techniques are given in Table 1-19. TABLE-1 Parameter Indian Attainable Integrated mill mills Fibrous raw materials, Debarked wood/ Bamboo 2.2-3.0 1.4-1.7 2.75-3.0 Bagasse (50% moisture), 5.8-6.2 - - t/t paper Salt Cake, kg/t 30-50 15-35 125-150 Caustic soda, kg/t 40-150 30-70 - Chlorine, kg/t 80-200 50-120 150-200 Alum, kg/t 50-150 20-80 - Lime, kg/t 350-500 250-400 500-600 Steam, kg/t 11-16.9 6.5-9.0 - Electric power, kWh/t 1288-1985 1100-1300 - Coal, t/t 0.77-4.2 - - Water, cu. M /t 200-400 20-140 - Chemical recovery, % 80-88 95-98 - Man Power, Nos/ 1000 annual t 50-120 10-15 -

TABLE 2 Characteristics of combined waste water from pulp and paper mill Parameter Large Paper Mills Small Paper Mills Range (Av) Agro residues based Waste Paper Range (av) Based Range (av) Flow, cu m /t paper 197-281(220) 187-383(252) 75-159(107) PH 6.6-10 6-8.5 7.1-7.7 SS mg/1 620-1120(764) 600-1115(615) 350-885(542) BOD5, 20o C, mg/1 240-380(295) 220-1067(698) 100-273(187) COD mg/1 840-1660(1118) 2120-4763(2940) 472-876(654) COD/BOD 2.95-4.37(3.8) 2.49-5.40(4.2) 2.7-5.7(2.4) Colour Pt-CO unit 300-655 15000-24000 - Lignin, mg/l - 320-700(563) - SAR 2.0-6.3(3.5) 4.7-7.6(6.4) -

12 Pollution load kg/t paper: SS 168 155 58 BOD 65 176 20 COD 246 741 70

TABLE 3 Solid waste generation in paper mills Waste Source Kg Dry Solid tonne paper Large paper mills Small paper mills Raw material handling preparation 45 210 for straws (550 for baggase) Hypochlorite preparation grit 20 - Recausticizing lime mud 593 - Power plant/Boiler ash 656 1300 Waste water treatment plant Primary sludge 159 116 Secondary sludge 34 105 Total 1507 1731(2071) % organic solids 16 25(35) % inorganic solids 84 275(65)

TABLE 4 Heavy polluting industries stack emissions (Permissible concentrations) Parameter Industrial area Residential/Rural area Sensitive SPM mg/cum 500 200 100 Dustmental mg/cu m (Fe, 50 30 15 Zn, Cu, etc) S03, H2SO4 mist mg cu m 100 50 20 S02 PPM 500 200 100 CO PPM 100 50 30 HC PPM 50 30 15

13 NH3 PPM 100 50 20 F PPM 50 30 15 Mercaptan 10 10 10

TABLE 5 Moderate polluting industries stack emission (Permissible concentration)

Parameter Industrial area Residential/Rural area Sensitive SPM, mg/cum 2000 1000 500 Iron dust, mg/ cum 1000 500 250 S02 PPM 5000 2000 1000

TABLE 6 Emission large pulp and paper mills

Particulate matter 250 mg/N cum* H2S 10 mg/N cum *To be reduced to 150 mg/N cum after October 1992

TABLE 7 Emission from Lime kiln

Capacity of kiln Parameter Standard Up to 5 T/day Particulate matter A hood should be provided with a stack of 30 m height from ground level (including kiln height) 5-40 T/day Particulate matter 500 mg/N cum Over 40 T/day Particulate matter 150 mg/N cum

TABLE 8 Guide lines for maximum stack height

For all plants except thermal power plants Stack height min 30 m 1. For plants where S02 emission is estimated as Q (kg/hr), stack height H in m is given by 0. 3 H=14(Q) 2. For plants where particulate emission is estimated as Q (Tonne/Hr) the stack height H in m is given by 0.27 H=74(Q) Maximum of the calculated value with minimum of 30 m stack height should be used.

14 TABLE 9 Quantum of odourous compounds from paper mill

Aoglb S02 H2S RSHa RSRa RSSRa S/ton pulp Digester vent 2 1-785 16-18,800 0-4,370 3,850-65,000 0-65,000 Blow gases 4 10- 0-782 0-9,840 522-46,900 0-10 1,050 Pulp washer 0.4 0.1-0.2 0-12 0-79 0 0.1-0.4 Evaporators Non 0.4 5-2,890 907- 455- 0-27,000 0-1,278 condensables 32,600 36,700 Recovery 21 4-789 14-1,140 0-498 0-260 0-17 furnace Smelt 0.6 0.5-70 10-44 0-212 0-91 0-4 dissolving tank Lime cooking 2.3 0-169 0-254 0-128 0-60 0-18 Tall oil 1.0 2-822 5,400- 0-4,660 0 103-769 cooking 101,000

Compound Boiling point o C Heat of Explosive Dissociation combustion K concentration constant of Cal/mole range in air % ag. Solution at 100 -7 -61.8 124 4.3 45.5 K1 = 21 x 10 H2S -14 K2<10. -11 CH3SH +58 299 2.2 9.2 K = 4.3 X 10 CH3S CHs +338 457 3.921.8 Not dissociated CH3S.SCH3 +118 530 Not determined Not dissociated

15 TABLE 11 Air quality standards for primary pollutants

Pollutant Tolerance ppm Levels micro g/ cum Relative toxicity CO 9.0 10,000 1,000 (Not to be exceeded more than once/year for 8 hour period) 35.0 40,000 (Not to be exceeded more than once/year for 1 hour period) Hydrocarbons 19,300 2.07 SOx 0.50 1,430 28.00 NOx 0.25 514 77.80 Particulates - 375 106.70

TABLE 12 Threshold values of some common air pollutants

Pollutant Values, ppm CO 50 F 1 HCl 5 HF 3 H2S 10 Hydrocarbon 500 NOx 5 03 0.05 S02 5

TABLE 13 Maximum permissible concentration of certain impurities in Air as per Air Pollution Act.

Substances Maximum concentration (mg/ cum) Av. Over 24 h At any instant Dust (20% silica) 0.15 0.50 S02 0.15 0.50

16 CO 2.00 6.00 NOx 0.13 0.40 H2SO4 0.10 0.30 C12 0.02 0.06 H2S 0.005 0.015 Pb 0.0007 0.002 NH3 0.10 0.30 Hg 0.0003 0.001 HCl 0.02 0.06 Soot 0.05 0.15 F 0.01 0.03 Phenols 0.10 0.30

TABLE 14 Stack emissions factors for pulp and paper mills

Source Unit Control Particulate S02 S03 H2S Mercaptan equipment matter Digester : Relief Kg/t pulp - - - - 0.80 0.02 Blow down Kg/t pulp - - - - 1.97 0.04

Rec. Kg/t BL ESP 13.4-26.5 0.28- 0.09- 0.06- 0.08-0.1 Furnace (0.93-8.53) 0.63 0.17 7.8 Smelt Kg/t BL - 0.17 Negi 0.02- Negib - dissolving ble 0.09 le tank vent Lime kiln Kg/t Lime Scrubbev 2.7-10.36 0.04- 0.06- 0.017 - 0.38 0.16 Power Kg/t coal Multi 47.7-49.45 1.16- 0.04- - - house Cyclone (3.82-20.76) 10.8 9.83 boiler

TABLE 15 Effect of exposure to various levels of NO2 on human health

Level of NO2, PPM Duration of exposure Effects on human health 50-100 Up to 1 hour Inflammation of lung tissue for 6-8 weeks. 150-200 - Bronchiolitics fibrosa obliterans-fatal result with in 3-5 weeks of exposure 500 or more 2-10 days Death

17 TABLE 16 Effect of continuous exposure to various levels of carbon monoxide

CO level, ppm % conversion of Effect of humans 02Hb to COHb 10 2 Impairment of judgement and visual perception. 100 15 Headache, dizziness, weariness. 250 32 Loss of consciousness 750 60 Death after several hour 1000 66 Rapid death

TABLE 17 National ambient air quality standards

Pollutant . Average time Primary standard Carbon monoxide 8h 10,000 micro g/cu in (9 ppm) lh 40,000 micro g/cu m (35 ppm) Hydrocarbons 3h 160 micro g/ cu m 0.24 ppm) Lead Monthly avg. 1.5 micro g/ cu m Nitrogen dioxide Annual avg. 100 micro g/ cu m (0.25 ppm) 1 h 500 micro g/ cu m (0.25 ppm) Photochemical oxidants 1 h 240 micro g/ cu m 0.12 ppm) Sulphur dioxide Annual avg. 80 micro g/ cu m (0.3 ppm) 24 h 365 micro g/ cu m 0.14 ppm) Total suspended particulate Annual geometric mean 75365 micro g/ cu m 24 h 260365 micro g/ cu m TABLE 18 Instrumental techniques are given in tables 1 — 19 Pollutants Instrumental techniques CO IR spectrophotometry (non dispersive), Gas chromatography S02 Spectrophotometry, Conductivity, Amperometry NO2 Chemiluminesene, IR spectrophotometry, Hydrocarbon spectrophotometry, Gas spectrophotometry NH3 Spectrophotometry, potentiometry Polycyclic aromatic hydrocaron Gas chromatography Volatile compounds Gas chromatography H2S W molecular absorption Particulate Matter Pollutants Instrumental techniques Silicates Chromatography Polycyclic aromatic hydrocarbons Chromatography Flourides Potentiometry Sulphates Electron spectroscopy TABLE 19 Element (Air/Particulate matter)

Pollutants Instrumental Techniques As AAS, NAA, S, XRF Be AAS, S, ES Cd AAS, XRF, S, ES Cr AAS, NAA, XRF, ES Cu AAS, NAA, XRF, ES Fe AAS, NAA, XRF, ES Mn AS, NAA, XRF, SES Pb AAS, XRF, S, ES Hy AAS, (Flameless), NAA, ES Zn AAS, XRF, ES Se NAA, XRF, S F P

AAS — Atomic Absorption photometery NAA — Neutron Activation Analysis XRF — X- Ray fluorescence ES — Emission Spectography

(V)Pollution control

The air pollution control needs are split between process and combustion sources. The process sources consists of NCG controls, pulp mill wastewater treatment, and bleach plant vent scrubbing (bleach pulp mill only). The combustion sources consists of HCl scrubbing of recovery boiler flue gases, and black liquor oxidation controls (BLOX if it at all exists). Steps to consider for control : Step 1: Identify each source of Emissions Step 2: Determine actual and potential emissions Step 3: Determine applicable emission limits Step 4: Determine whether emissions comply with all applicable limitations Step 5: If necessary, propose a compliance schedule Step 6: Propose measurement, record keeping and reporting methods Step 7: Select an appropriate equipment and operation to meet the target

19 (VI) Monitoring of liquid effluents I.COLOUR - Visual comparison method-Pt-Co method of.measuring colour is the standard method - Spectro — photometric method - Tristimulus Filter method 2.TURBIDITY - Nephelometric method - Visual method — Jackson method 3.TEMPRATURE 4.TOXICITY 5.TASTE - Taste threshold test -Taste rating method 6.ODOUR 7.INORGANIC ANALYSIS -Acidity -Alkalinity -ph -Dissolved solid a) Argentometric method b) Mercury Nitrate method c) Potentio metric method d) Automated Ferriccyanide method . Nitrogen Ammonia -Sulfides -Heavy metals 8.ORGANIC ANALYSIS -BOD -COD -Total Organic Carbon (TOC)

20 9.CHARECTERIZATION OF SOLID FRACTION -General sludge -characteristics a) Sludge settling characteristics b) Sludge volume index 1) MLSS 2) MLVSS 3) Sludge specific resistance 4) Compressibility cofficient -Chemical composition of sludges -Biological characteristics of sludges 10.SAMLING OF EFFLUENT INSTRUMENTAL TECHNIQUES FOR AIR POLLUTANTS Gaseous Air Pollutants Analysis of particulate method: The standard method for particulates in the high volume method uses a high volume sampler. Samples analyses are detailed in standard method of analysis. (VII) CORPORATE RESPONSIBLITIES (CREP) SN CREP Action Point Status A. Large pulp and paper mills (wood based) 1. Discharge of Absorbable -Before CREP AOX level was between 2-2.5 kg/tonne Organic Halides (AOX) of paper - 1.5 kg/tonne of paper -After CREP, llmills achieved AOX level? 1.5 within 2 years (1 st April, kg/tonne and 8 mills achieved AOX level?1.0 2005) kg/tonne of paper by using cleaner technologies like - 1.0 kg/tonne of paper in oxygen delignification and chlorine-di-oxide 5 years (1 st April, 2008) substitution 2. Waste water discharge -Before CREP the discharge level was between 180-5- < 140 cum/tonne of paper 250 cum/tonne of paper. within 2 years i.e. April, After CREP, waste water discharge level has come

21 2005 down? 140 while in 10 mills it is even less than 120 < 120 cum/tonne of paper cum/tonne of paper. in 4 years for units installed before 1992 i.e. April, 2007 < 100 cum/tonne of paper for units installed after 1992. 3. Installation of lime-kiln 9mills have installed Lime kiln and rest of the mills for recalcination of lime have submitted action plan for lime kiln installation. sludge within 4 years (1st The installation by these mills is under different April,2007) stages. 4. Odour control by burning One of paper mills have installed odor control system. reduced sulphur emissions Other mills have submitted action plan for its in the boiler/lime-kiln implementation. Many mills requested for extension within 4 years. for another year. 5. Utilization of treated 10 units partially using treated effluent for irrigation. effluent wherever possible. 6. Colour removal from No project has been given by the IPMA to CPPRI as effluent. (IPMA to take up decided by the task force. One of the mill (M/s the project on colour Century pulp and paper mill, Lalkua) is participating removal with Central pulp in demonstration of color removal project of CPCB. and paper research The plant is under trial run. institute.) B. Small scale agro-based pulp and paper mills (Agro- based) 1. Recovery of chemicals by Response from 62 mils received out of 70 mills. The installation of Chemical different approach followed by the mills for utilization recovery plant (CRP) or of black liquor and for shifting to waste paper are utilization of black liquor below:

22 with no discharge from i)Nos of mills installed CRP-8 pulp mill within 3 years (1 ii)Nos of mills installing CRP-9 st April, 2006) or shift to iii)Nos of mills shifted to waste paper-19 waste paper for iv)Nos of mills shifting to waste paper-11 compliance of standard of v)Nos of mills installed lignin sepration plant-3 BOD,COD & AOX. vi)other agro-based mills are in process of installing lignin recovery plant-12 2. Up gradation of ETPs in Only 4 industries informed about up gradation of their one year so as to meet ETP. Other mills informed that ETP is adequate. discharge standards However, IPMA requested extension for another year. 3. Waste water discharge < General waste water discharge is 100-150 cum/tonne 150 cum/tonne of paper for bleached grade and 75-125 cum/tonne of paper in within 3 years (1 st, April case of unbleached grade. 2006) 4. Utilization of treated 8 Agro-based mills are utilizing treated effluent for effluent for irrigation irrigation. wherever possible. 5. Colour removal from No project has been given by the IARPMA to CPPRI effluent. (IARPMA) to take as decided by the task force. up the project on colour removal with Central pulp & paper research institute.)

23 (VIII) CREP FOR PULP AND PAPER INDUSTRY Large pulp and paper a,no~e,~~,r~ Implementation schedule Discharge of AOX kg/tonne paper AOX 1.5 kg/tonne of paper within 2 years AOX 1.0 kg/tonne of paper within 5 years Installation of lime kiln Within 4 years Wastewater discharge cum/tonne of paper Less than 140 cum/tonne of paper within 2 years Less than 120 cum/tonne in 4 years for units installed before 1992 Less than 100 cum/tonne of paper per units installed after 1992 Odour control by burning the reduced Installation of odour control system within sulfur emission in the boiler/lime kiln 4 years Utilization of treated effluent for irrigation Utilization of treated effluent for irrigation wherever possible. Colour removal from the effluent Indian Paper Manufactures Association to take up project with Central Pulp & Paper Research Institute. Small Pulp And Paper i'voStv~. Compliance of standard of BOD, COD & Recovery of chemicals by installation of AOX Chemical recovery plant or utilization of black liquorwith no discharge from pulp mill within 3 years or shift to waste paper Up gradation of ETPs so as to meet ETPs to be upgraded within 1 year so as to discharge standards meet discharge standards. Waste water discharge/tonne of paper Less than 150 cum/tonne of paper within 3 years Utilization of treated effluent for irrigation Utilization of treated effluent for irrigation

24 wherever possible. Colour removal from the effluent Indian Agro and Recycled Paper Manufactures Association to take up project with CPPRI.

Non complying units not meeting notified standards under Environment (Protection) Act,1986 will submit action lan with PERT chart along with bank guarantee to SPCBs by June 30,2003 (IX) NATIONAL ENVIRONMENTAL STANDARD IN PULP AND PAPER INDUSTRY (from 1s" April,2005)

Parametre Agro based mills Large pulp and paper mills A. WATER POLLUTION Effluent discharge, cum/t 150 from I" April, 2006 < 140 from 1st April, 2005 AD paper • < 120 from 1st April, 2007 < 100 from 1st April, 2003 for mills set up after 1992 COD, mg/l 350 350 BOD, mg/I 30(100**). 30(100**)

AOX, kg/t AD paper 2.0 from 15` March, 2006 < 1.5 from 1s` April, 2005

1.0 from 15` March, 2008 < 1.0 from 1st March, 2008 Up gradation of ETP With in 1st April,2004 Colour removal IARPA to take up project IPMA to take up project with CPPRI with CPPRI Utilization of treated Wherever possible Wherever possible effluent for irrigation B. Air Pollution Particulate matter,mg/N 150 150 cum S02,mg/Ncum Proper gas dispersion Proper gas dispersion

25 (governed by stack height) (governed by stack height) H2S,mgfNcum 10 - Cl2,mg/Ncum 15 15 NCG Incineration system from Is` Incineration system from 1st April, 2007 April, 2007 C. Hazardous wastes Spent chemicals Spent chemicals Corrosive wastes arising Corrosive wastes arising from use of strong acid and from use of strong acid and bases bases Sludge containing Sludge containing adsorbable organic halides adsorbable organic halides D. Solid wastes Fly ash utilization - Free availability of fly ash - Free availability of fly ash upto 2013 upto 2013 - 20% utilization within - 20% utilization within 2006 2006 - Progressive increase in use - Progressive increase in use every year up to 2018 every year up to 2018 -100% utilization 2018 -100% utilization 2018 Utilization of lime sludge Installation of lime kiln for lime sludge reburing with in 1st April, 2007

26 CHAPTER -4

MAGNITUDE OF POLLUTION FROM PULP AND PAPER INDUSTRY IN INDIA Pulp and paper industry has been responsible for important technical, social and economic impacts in a country. In India, machine made paper industry is a little over a century old and has made considerable progress during the last 30 years. A large number of small paper mills of 30 TPD capacity and below have come up in resent years utilizing the abundantly available agricultural residues, waste paper etc. the quantity of paper made by small mills accounts for nearly 20% of the total paper and board production. As small mills do not go in for chemical recovery, as it is not economical, the entire black liquor is discharged as pulp wash water. 1.0 MANUFACTURE OF PAPER: 1.1 Raw Materials : Bamboo continues to be the main cellulosic raw material for the industry. Hard wood and others such as eucalyptus, salai, pine, grasses, bagasse, hemp, rags and waste of bamboo and wood. 1.2 Water Requirements : Water usage is high in paper industry and vary from 300-425 m3/ton of paper. The requirement for water is least in straw and paper board mills (75-100 m3/ton) and highest in speciality paper mills (370- 1220 m3/ton). The water usage so far in Indian pulp and paper industry is based on the availability of raw water and its cost of processing and supplying. It is often observed that water is the most misused commodity in the industry. 1.3 Process Of Manufacture : Practically all the integrated pulp and paper mills in India adopt sulphate, Kraft or other process of pulping. Small paper mill use caustic soda or lime for pulping with no chemical recovery. Schematic diagrams showing the manufacture of paper and sources of pollutants for large and small mills are given in figures. or1 1ane~~ca~c1 c~

27 The cellulosic raw materials are chipped to suitable size and cooked with caustic soda and sodium sulphide in kraft pulping, caustic soda in alkali pulping, magnesium sulphite, sodium sulphite and sulphur dioxide in sulphite process. About 48% of wood organics get dissolved in kraft digester and constitutes black liquor. The black liquor is subsequently concentrated and burnt to recover alkali, sodium sulphide, heat and steam, for power generation. Pulp is washed, bleached with chlorine, extracted with alkali and again treated with hypochlorite. Final bleached pulp yield is about 42% by weight of the wood used. Pulp along with fillers etc. goes to to give the desired end product. In small paper mills, agricultural residues after proper size reduction are cooked with caustic or lime. Black liquor, which contains about 50% of the organics of the raw material, is not separated and recovered for chemicals. The pulp after washing is bleached with hypochlorite, mixed with waste paper pulp and made in to paper. 2.0 SOURCES OF POLLUTANTS: 2.1 LIQUID WASTES : During the manufacture of paper, waste waters are released from different unit processes : Digester House Leaks and spills of black liquor and gland cooling water. Pulp Washing The final wash, often referred as brown stock wash or unbleached decker wash. CentricIeaners Rejects containing high concentration of fibers, grit or sand. Pulp Bleaching a) consists of chlorination stage water with low ph and chloro lignin b) caustic extraction water, dark brown in colour with high ph chloro lignins and c) hypochlorite waste water. Paper Machine Often referred to as white water, contains fibers, talc and sizing chemicals and a part of the water recycled for wood washing and other operations in the mill. Chemical Recovery Spills of black liquor in the evaporators and foul condensates. 2.1.1 Volume and pollution characteristics : Pollution Load Min Max Avg Volume of water m3/ton 214 352 305 SS, Kg/ton of paper 88 188 131 BOD5, Kg/ton of paper 35 76 51 COD, Kg/ton of paper 155 321 217 Per cent sodium 31 58 47

Table 1 Characteristics of waste water from factory Installed capacity, TPD 130 Raw material Salai + Bamboo Process Mechanical + sulphate with chemical recovery Volume of waste water m3/ton paper 261 Colour Light brown Ph 7.2-7.3 Total solids, mg/1 1439 Suspended solids, mg/l 375 BOD5, mg/l 165 COD, mg/l 508 Total Nitrogen, N, mg/1 5.8 Total phosphours P mg/l 1.7 Pollution load, kg/ton paper SS 98 BOD 43 COD 133

2.2.2 Toxic component in pulp and paper mill waste waters Data have been reported from different parts of the world on the nature of organic compounds present in black liquor, waste waters from pulp washing chlorination, alkali extraction etc. and their toxicity to the fish and other aquatic fauna and flora. However, no work carried out in this regard in India. ti Apart from toxicity, some compounds present in pulp and paper mill waste waters show mutagenic effect i.e. a change in genetic code of the living cell. It has been found that only the chlorination stage wastes produce significant mutagenicity which decreases almost linearly with increasing substitution of chlorine dioxide for equivalent chlorine for bleaching. Chlorination of pure lignin as well as ground wood, kraft and sulphite pulp

29 also produced mutagenicity. The lignin component of the pulp appears to be responsible for mutagenecity. Fortunately much of the mutagenLcity is lost when waste water ph is raised to 7-88 as it is the normal practice, before discharging bleach plant wastes to the treatment plant or in to receiving water. The major polluting constituents in pulp and paper and rayon pulp mill waste waters are suspended solids, colour, foam, inorganics, BOD and COD. They also contain appreciable quantities of toxic organics and inorganics. Lignin and its derivatives impart colour and exert high toxicity. Discharge of untreated wastewater into water courses will damage the water quantity and the colour would persist for long time. Paper mills are located all over the country and only few of them provide treatment. No river is spread from pollution due to these wastes. Data on water pollution by pulp and paper industry in terms of suspended solids, BOD, COD loads from the three groups of mills i.e. i) integrated mills with chemical recovery, ii) small mills with pulping facility and no chemical recovery, and iii ) small mills employing waste paper are given below. Table 2 Pollution load in terms of Volume, SS, BOD and COD from pulp and paper industry in India

Integrated pulp & Small mills with Small mills employ- To paper mills with pulping facility with ing waste paper & chemical recovery no chemical recovery purchased pulp Installed 1235 (74.5) 245 (14.8) 177 (0.7) 16 Capacity X103TPA

Volume, 1032.3 (82.7) 149.5 (12.0) 66.3 (5.3) 1248 X 103 m3/d

SS, tones/d 443.4 (56.7) 193.1 (24.7) 145.1 (18.6) 781

30

BOD, tonne/d 172.6 (53.3) 116.7 (36.1) 34.3 (10.6) 323

COD, tonne/d 734.4 (56.7) 388.9 (30.0) 171.8 (13.3) 1295

Figures in parenthesis indicate % of total. Pollution equivalent in terms of BOD — 7.12 X 10 6 ( one person contributes about 45.45 g BOD per day) Having nearly 75 % of the total installed capacity the large mills account for 83 % of waste water flow, 53 % BOD .and 57 % each SS and COD loads of the total pollution contributed by the industry. On the other hand, small mills with 25 % installed capacity contribute 47 % of total BOD, 43 % each for total SS and COD load contained in only 17 % of the total wastewater generated by the industry. The small paper mills contribute strong wastewater and the magnitude of pollution nearly equal to that of large mills. The daily BOD discharged by the industry is equivalent to the BOD present in the sewage daily generated by population of 7.12 million. Table 3 CHARACTESTICS OF WATE WATERS FROM SULPHATE PULP AND PAPER MILL

1 2 3 4 5 6 7 8 WEIGHTED A

Installed capacity TPD 230 205 190 180 165 140 140 125

Raw Materials Bamboo Bamboo Bamboo Bamboo Bamboo Bamboo Bamboo Pine wood wood wood wood wood wood wood eucaly- rags rags rags plus waste paper

Volume of waste water 214 350 300 313 352 343 316 253 305 m3/tonne paper

31 Colour Dark Dark Dark Dark Dark Dark Dark Dark Dark brown brown brown brown brown brown brown brown brown

Ph 6.5-8.0 6.6-10.2 7.1-8.2 9.8 7.0-7.6 5.6-11.8 7.3-8.0 7.6

Total solids, mg/l 1770 1442 2014 1920 1186 1380 1210 1590 1542

Suspended solids, mg/1 410 386 503 600 290 400 . 423 380 430

BOD5, mg/l 161 235 188 210 100 122 165 190 167

COD, mg/l 725 674 750 760 585 620 498 1270 711

Lignin, mg/1 ------109 ------82 ------95

Total Nitrogen, N, mg/l ------3.2 4.5 5.8 ------1.8 0.8 ------3.2

Total phosphorus, ------0.6 0.8 1.3 ------2.4 0.3 ------1.1 P, mg/1

% sodium 34 52 35 54 58 31 56 M

Pollution load kg / tonne

Suspended solids 88 154 151 188 102 137 134 96 131

BOD 35 76 53 66 35 42 52 48 51

COD 155 238 213 234 206 213 158 321 217

Linin ------32.7 ------28.9. ------29

32 Table 4 CHARACTESTICS OF WASTE WATERS FROM SMALL PAPER MILLS

1 2 3 4 5 WEIGHTED AVG

Installed capacity TPD 36 20 22 6 28 ------

Raw Materials Rice straw, Waste, Baggase, Waste Baggase ------rags, waste Cotton, waste paper paper, paper hessian hard wood rice straw Waste paper

Process Soda, no Soda/lime Soda, no Soda, no Soda with ------recovery No recovery recovery recovery chem. recovery

Volume of waste water 208 136 330 216 455 223 M3/tonne paper

Colour Dark Dark Dark Dark Dark Dark brown brown brown brown brown brown

Ph 8.0-9.0 10.6 8.2-8.5 7.0-9.4 5.6-6.3 ------

Total solids, mg/1 3550 2500 5395 3780 1488 5129

Suspended solids, mg/1 1430 860 1245 1510 816 1293

BODS, mg/l 780 320 1020 710 350 782

COD, mg/l 2680 1121 3470 2160 1278 2608

33 Pollution load kg / tonne

Suspended solids 297 117 411 326 371 288

BOD 162 44 337 153 159 174

COD 557 152 1145 457 581 580

Mill no 5 is not taken for working out average as this mill recovers soda. Table 5 CHARACTERSTICS OF WASTEWATER FROM SMALL PAPER MILL USING WASTE PAPER ONLY

Pollution load (kg/tonne product)

Volume, m3/tonne 137

Colour White to light blue

5.5-7.0

Total solids, mg/l 2900

Suspended solids, mg/1 2190 300

BOD 5, mg/I 520 71

COD, mg/1 2590 355

% sodium 24

34 Table 6 CHARACTERSTICS OF WASTEWATER FROM RAYON PULP MILL

(1) (2) Installed capacity, TPD 100 165

Raw material Eucalyptus, wood Bamboo

Process Water pre hydrolysis & Acid pre- sulphate pulping with hydrolysis chemical recovery & sulphate pulping with chem. Recovery

Volume of waste water, 176 250 m3 / tonne paper

8.5-9.3 8.0-9.0

Total solids, mg/1 3260 3000

Suspended solids, mg/1 1180 200

BOD, mg/l 535 1200

COD, mg/l 2070 1600

Pollution load kg/tonne pulp Suspended solids 208 50

35 BOD 5 94 300

COD 364 400

Table 7 SUMMARY OF TOXIC COMPOUNDS IN PULP WASHING AND BLEACHING PLANT WASTE WATER

Nature of chemical Toxicity compound Specific organics contribution

Pulping Bleachery Caus Chlorination tic Extra- ction

Naturally occuring acids Abietic, dehydroabetic, isopimaric Major Minor Minor levopimaric, palustric pimaric, sandaracopimaric, necabietic

Chlorinated lignin ------Major

Chlorinated resin acids Mono and dichloro dehydroabietic -- Interrr. diate Chlorinated phenolics Tri and tetrachloro guaicols, -- Intern. phenols chloro-vanillins diate

Unsaturated fatty acids Oleic, linolenic, linolenic palmitolic Intermediate acids

Other acids Epoxy stearic and dichloro stearic acid ------Intern acid diate.

Terpenes Diterpene alcohols and aldehydes ------Minor

36 2.2.3 Gaseous and particulate emissions from kraft pulp and paper mills During cooking of wood chips in kraft pulping a part of sodium sulphide reacts with lignin and carbohydrates in wood to form malodorous sulphur compounds such as hydrogen sulphide (H2S) Methyl mercaptan (CH3SH) . dimethyl sulphide (CH3SCH3). Other gaseous emissions include oxide of sulphur (SOX) and nitrogen (NOX). The particulate emissions include sodium sulphate and carbonate from recovery furnace: Sodium compounds and calcium carbonate are discharged from the flue gases of lime kilns. Suspended particulate matter (SPM) are also released from auxiliary power generation plant in the paper mills. Both H2S and organic sulphides are extremely odorous and are detectable at a few parts per billion concentration. Odour is one of the principal air pollution problems in mills. The emission sources include the following — 1) Digester relief gases 2) Digester blow tank and washer hood vent gases. 3) Black liquor evaporation gases. 4) Chemical recovery furnace emissions. 5) Smelt dissolving tank gases. 6) Power boiler emissions. 7) Lime recovery klin emissions.

Table 8

CHARACTESTICS OF GASEOUS EMISSIONS FROM KRAFT MILL PROCESS

Emission Emission rate kg, sulphur per tonne air dried source Flow rate Temp. Moisture pulp

H2S CH3SH CH3SCH3 CH3SSCH

37 Digester - Batch 3-6000 65-100 30-99 0-0.1 0-1.0 0-2.5 0-1.0 blow gases

Releif gases 0.3-100 25-60 20-Mar 0-0.05 0-0.3 0.05-0.8 0.05-1.0

Digester contenious 0.6-6.0 75-150 35-70 0-0.1 0.5-1,0 0.05-0.5 0.05-0.4

Washer hood vent 1500-6000 20-45 2-10 0-0.1 0.05-1.0 0.05-0.5 0.05-0.4

Evaporator hot well 0.3-12 80-145 50-90 0.05-1.5 0.05-0.8 0.05-1.0 0.05-1.0

BLO Tower exhaust 500-1500 70-80 30-40 0-0.01 0-0.1 0-0.4 0-0.3

Recovery furnace 6000-12000 120-180 25-35 0-25 0-2 0-1 0-0.3

Smelt dissolving 500-1000 70-110 35-45 0-1 0-0.8 0-0.5 0-0.3

Lime klin exhaust 1000-1600 65-95 25-35 0-0.5 0-0.2 0-0.1 0-0.5

Lime slaker vent 12-30 65-75 20-25 0-0.01 0-0.01 0-0.01 0-0.01

At standard condition of dry gas (21.1 degree c and 760 mm Hg) In India lime is not recovered practically in all mills. Black liquor oxidation (BLO) is not adopted in most of the mills in India. The pulp and paper industry discharges a variety of wastes in gaseous, liquid and solid phases in to environment. The industry releases about 1.25 million m3 of waste water per day with SS, BOD and COD loads of 800, 350 and 1400 tonnes approx. respectively. Pollution load from small mills is nearly equal to that of big mills although the paper production in former case is only 20 percent of the total. This is due to the non-recovery of chemicals from black liquor in small mills. The daily pollution load contributed by the pulp and paper industry is equivalent to that contributed by about 7.2 million people. A variety of malodorous organic and inorganic volatile sulphur compounds released during kraft pulping currently being used in India. Further flue gases and particulates are discharged by the industry from recovery furnace and auxiliary power boiler. Data are not available on different gaseous emissions from the Indian mills. About 4 % of the wood processed ends up as chipper house dust and rejects. In addition, about 550 kg of dry lime sludge is generated per 1000 kg of paper made and is not recalcined by the industry for lime recovery. Hence in presents significant solid waste problem. In a good no of cases, the lime sludge is slurried and discharged along with liquid wastes adding to water pollution. Other solid wastes include the boiler ash and fly ash from auxiliary power boilers. Nearly 340 to 350 kg ash is discharged 1000 kg coal used for power generation.The pulp and paper industry releases wastes in solids, gaseous and liquid forms, which need be treated effectively to minimize environmental damage.

39 CHEPTER 5 ENVIRONMENTAL POLLUTION FROM PULP, PAPER AND STRAW BOARD FACTORIES IN INDIA

The raw materials used for pulp and paper are generally locally available bamboo and hard wood in approx. 70:30 ratio with variation suit the product. For mill board etc, the material used are rags, waste paper, cotton waste etc, while straw boards generally use the wheat or rice straw, an agriculture by product. The most of the pulp and paper mills use sulphate process for manufacture. Hydro pulping or mechanical pulping is used in boards manufacture and for straw board batch digestion using sulphate process is commonly used. 1.0 ENVIRONMENTAL POLLUTION PROBLEMS As per experience in such mills all the world over, environmental problems of pulp, paper and straw board factories can be divided in four categories : 1) The effect of ecology destruction of trees and bamboo clumbs for requirement of wood, land use for factory and residential purpose, ' transportation and other strains on the system. 2) Air pollution — sulphides mercaptons etc. odorous gases , oxides of sulphur, soot or fly ash. 3) Water pollution — liquid effluents carrying Iignin organic materials like fibers, and water soluble cellulose and also toxic metals like mercury etc. 4) Solid waste — chipper dusts, lime sludge and waste treatment plant sludge. The studies carried out in India show that the quantity and the quality of the pollutants released in the air, water and soil from different factories varies considerably, depending upon following factors: 1. Size of the factory, i.e. large capacity factories have controls and release less pollutants per unit production. 2. Complexity of the products with large range recycle probability is more with reduced pollution. 3. Raw materials used, bamboo generates different characteristics of wastes, than those from hard wood in Europe and America. 4. Process used. 5. Age of the plant, old factories generate more pollution. 6. General maintenance and house keeping standard in factory. 7. Damage of natural system by cutting trees may be irreversible or reversible depending on degree and nature of intervention by human, soil erosion, desertification and wild life obstruction may be extensive. 2.0 Large pulp and paper factory: 200 MT/day capacity In this mill sources of water pollution are: 1 Chipper house waste 2 Brown stock washer-and knotters 3 Bleaching section, acid and alkali washer 4 Paper machines 5 Soda recovery section, multi stage evaporator discharge 6 Lime kl line hydrolysis 7 Sanitary of other misc. waste Table no 1 MATERIAL REQUIRED PER 100 TONNES OF PAPER PER DAY

Lost (Tonnes) Materials Required Retained Amount As With Recovered Remar (tonnes) (tonnes) (Tonnes)

Bamboo & wood 226 82 7.8-10.0 Chipper dust - - Now v~ 131.4 Alkali Lignin Black ligour Serves as Evepo Thio - lignin & fuel in Conde Hemicellulose soda Re- has hic etc covery load furnace 2.3 Chloro lignin Bleaching plant during ble- effulent - 3.3 aching fines Paper mac -

41

hine effulent Alkali as NaOH for 36-48 4.5-6 Fumes, dust Recovery stack 31.5-42 pulping Leakage and gas with pulp Lime for caustici- 42-50 42-50 Lime mud - - sation (as 65% CaO) (61-72)

Lime for bleaching 5.0 5.0 CaCl2 etc Bleaching plant - liqour effulent

Chlorine 10.0 10.0 CaCl2 and do - Chloro lignin

Alkali as NAOH 2.0 2.0 During do - Browni Bleaching washing liquid

Resin for sizing 2.0 1.2 0.8 - Paper mac- - hine effulent Alum for sizing 5.0 0.75 4.25 - do -

China clay and talc 20.0 12.0 8.0 Fines for loading

Fuel as Cpa 300-400 - 240-320 Fuel - - 60-80 Clinder - -

Water 25000- 3.5-4.0 25000- Effulent - - 40000 (Moisture) 40000

42 Table no 2 CHEMICAL COMPOSITION OF PAPER MILL WASTE WATER TYPICAL 200 T/DAY PLANT

Parameter, Waste water The waste Tolerance limits from paper water as per IS :3307 mill After An- for land (coloured) aerobic irrigation lagoon treatment

Ph 9.8-10.8 7.6-8.9 5.5-9.0 ECX103 2.7 2.2 - Ca ++ Ma/I 0.9 2.5 - Mg ++ Ma/I 0.3 0.3 - Na ++ Ma/I 24.9 18.3 - K + Ma/I 0.7 0.4 - CI - Ma/I 4.2 8.2 600-mgle CO3 Ma/I 16.3 0.0 - HCO3 Ma/I 3.8 12.8 - SO4 Ma/I 2.2 1.6 - SAR 32.1 15.9 - RSC 18.9 10.0 - Organic matter% 0.7 0.63 Suspended solids, mgle 406 148 Total dissolved solids, 2494 2184 2100 Mgle Total solids, mg/I 2900 2184 BOD, mg/I 433 187 500 mgle COD 5 mg/I 2107 1181 Colour 1100 1100 Alkalinity 280 182 Mercury (Hg) 0.18 mg/I 0.14 mg/I Iron not done not done % Sodium 92 85.1 60% Oil and Grease 10 mg/I 9 Alpha emitters .ug/ml 10 -8 Beta emitters ua/ml 10

43 SP = soluble solid per cent AR = sodium adsorption ratio RSC = residual sodium carbonate DB = dark brown The source of air pollution are generally digester house blow tank brown stock washer, knotters, black liquor concertrator, smelt dissolving tanks, lime kiln and steam boilers. The solid waste sources as described in table arsechipper house fires, caustiai3or lime A- sludge and dried sludge from the treatment plant. The liquid waste is discharged into a medium size river which has minimum flow of about 60,000 m 3/ day. The factory draws about 50,000 m 3/day from river and discharges it back thus virtually entire river becomes effluent during dry months. The solid wastes are generally dumped around the factory premises as they have some land available around. Such a mill will use 600 tons of wood of which about 480 tons of bamboo and 120 tons of hard wood. The impact of 480 tons of bamboo will be equivalent to removal of bamboo from 480x3=1500 acres(or 1500x2.5=600 hecteres of area) would be deforested or declumbed from bamboo and approx. 120 medium size trees per day. The transportation load on the road and railway system will be difficult to assess but depending on the location of forest may need 3 to 6 km. Or road construction and will accrue approximately 2 million tons km of additional burden on transportation system.

Table no 3 AIR POLLUTION FROM PULP AND PAPER MILL ( CAPACITY 200 T/DAY) ALL VALUES IN Kg/day

Source Particular Sulfur Oxides Carbon Sulphide disulphides Arsenic Mono oxide mercaptons Mercury

•Chipper house 500 - - - - Blow tank + washer - - 440 - and screen

Black liquor

concertrator - - - 120 -

Recovery 11.0 Mercury boiler 2000 500 680 1400 from soda ash

Smelt dissolving

tank - - - 8 -

3.0 Fl.

Lime Klan 150 50 10 - Flourides from lime and coal

Steam 3.2 Arsenic- Generator 4800 64 - - Arsenic (800 tonnes of coal/day) from coal

Table no 4 Typical Solid Waste from pulp and paper mill 200 Tlday

Source Tonnes/day Remarks

Chipper house 14-20 Fines rejected by screen

Causticiser 120-150 Lime sludge wet with 40 to 60 % moisture

Treatment plant sludge 30-50 Dried sludge from clari- fire bed.

45 3.0 The Rayon Grade pulp factory This factory produces 180 tonnes of rayon grade pulp/day used prehydrolised kraft process. The raw material again is bamboo mixed with long fiber hard wood of indigenous source. The factory is located at 22 km from sea on a river. It draws about 50,000 m 3/day of water and discharges 48,000 m 3/day back to river as effluent. The characterstics of the liquid effluent is given in table. The main source of liquid effluent are I Chipper house 2 Digester house 3 Brown stock washing 4 Bleaching (i) Alkaline (ii) Acidic 5 Pulp washer 6 Evaporator/Concentrator 7 Lime kiln 8 Ecology The concentrated digested waste accounts for the 80% of BOD and is treated separately in arobic and aerobic lagoon followed by aerobic lagoons. The other waste are only clarified after which all the waste are finally treated in a stabilization lagoon. The air pollution from this factory is from digestor house, blow tank, evaporator concentrator , lime kiln and steam generation. Calculated values are given in the table. The solid waste produced are also given in the table. The solid waste from this factory is also similar to those from pulp and paper mill generated from chipper house lime stacking and clarified sludge. The disposal of this is being done by dumping them on available process around the factory. The situation will be similar to the pulp and paper mill situation as described earlier as requirements are almost identical affecting tranportation forest natural systems etc. Table no 5

Solid Waste : 190 t/day sulphide pocess - pulp mill

Quantities

Source Tonnes/day Remarks

Chipper house 19-20 Fines reject.

Causticiser 100-130 Lime sludge

Clarifier 20-25 Sludge - Returned to board mill

47 Table no 6

Volume and charterstics of Prehydrolysate and combined Effluent from typical 190 T/day mill

Total TSS COD BOD Daily load in Tonnes Colo Description ur Total flow Ph solids mg/I mg/I mg/I COD BOD TSS m3/d ma/I

Ph liquor and Ph wash 6000 1600 3 40000 800 60000 30000 96 48 1.28 Mixture

Combined Effluent 2000 32000 8.5 3000 250 1500 - 300 48 9.6 8

Combined Effluent . 600 32000 8 - - 800 165 25 5.3 - after Hypotreatment

Charectersics of Final 500 48000 7.5 - 150 500 200 24 9.6 7.2 Effluent (Dischargeble) of water/day. It also discharges 10,000 to 12,000 m3/effluent per day into the river. The typical char~cterstics of these effluent are given in table as under. Table no 8 Result analysis of the samples collected from different sections from the small fac- 55 T/day mill (All values except Ph and flow expressed as mg/l)

Tests Black . Soda Recovery Brown stock Sreening Bleaching liquor Section wash knotters etc.

Flow (m3/day) 100 3500 - - 8000

Ph 10.8 9.1 8.6 6.3 6.5

Alkalinity(CaCO3) 38000 280 200 90 100

COD 14680 480 1440 194 540

BOD 25000 126 310 60 130

Total solids 241590 115 1960 460 2060

Suspended solids 19130 400 660 200 160

BOD load kg/day 2500 441 - - 1040

BOD load kg/ton 45.5 8.0 - - 18.9 paper/dav Table no 9 1 Results of analysis of combined effluents from pulp washing, soda recovery and screening etc. section (All results except flow, Ph and colour expressed as mg/I)

50

Table no 7

190 T/day pulp factory ( sulphide process ) Air Pollution Kg/day

Source Particulate Sulpher Carbon Sulphides Mercury/ Remarks matter oxide monoxide mercaptons Arsenic

Chipper house 360 - - - -

Blow tank - - - 380 -

Black liqour concentrator - - - 100 -

Recovery boiler 1600 480 580 1300 10 from the alkaline lime Smelt solutionising - - - 7.8 -

Team 260 Tons/day oil 520 15600 130 - -

4.0 Medium size factory 50 T/day capacity This is a medium size paper mill producing approximately 45-50 tons of paper per day. The mill uses again bamboo ,reeds and some hard wood about 10% as raw material.The sulphate process is used for pulp making and it practices partial recovery of the chemicals. This factory is located on an inland river and uses approximately 12500 tons Tests 1 2 3

Production in tons/day 55 55 40

Flow (m3/day) 12000 12400 9230

Ph 6.6 6.9 8.6

Colour 1180 680 950

Alkalinity(CaCO3) 224 230 270

COD 680 600 480

Total solids 1306 1250 1050

Dissolved solids 900 880 840

Suspened solids 400 370 210

BOD load kg/day 1920 1910 1108

BOD load kg/ton of paper/day 34.9 34.7 27.7

The case study of small mill board factory shows that this factory has a capacity to produce approximately 50 T/day boards per day. The raw material used are bamboo, pulp, waste paper of different grades and some cotton waste for manufacturing various quality teaks of boards. The process used for hydro pulping : It uses approximately 100 tons of water for per ton of paper produced per day. The total is approximately 550 tons of waste water per day. The characteristics of the effluent from the various sources in the mill is given in table no 8. The treatment is given in this plant consists of fiber recovery for flotation method

51 followed by sedimentation for a period of 3 hrs. Settled effluent is discharged through an open field when it flows for a distance of approximately 1.2 kms before it meets the river which has discharge of approximately 4 cuc. Meter per sec. This factory has all the materials such as pulp, waste paper, alkali, fillers etc. brought in from out side sources and there—fore generates no solid waste. Also because of hydropulping process air pollution ri does exist in this factory. A straw board factory is located in heavy rain fall area about 48 kms from the sea. It uses about 28 tons/day of rice straw ( paddy straw) available from near by areas. The sulphate used is by a batch digestor 4 batches per 24 hrs where the digestors are emptied in an open pit for digestor liquor and fiber separation. The liquor is dried on earthen bed while other wastes are discharged into narrow stream. During monsoon months the entire waste including digestor liquor is discharged into the river. The data of water and other pollution are given in Table no 9. The factory has no chemical recovery hence entire load of lignin pollutes the stream heavily. The solid waste generated in this factory is due to dried lignin liquor cakes from the drying beds. Environmental Impact of Pulp and Paper Factories The major environmental impact of concern in India are due to location of these factories on inland rivers and there-fore water pollution and solid wastes in them are described as follows: a) Water Pollution : 8 major factories with 150 tons/day capacity are responsible for very severe pollution of the stream stretches of rivers extending 150-200 kms. This affected water supply of six town over 50,000 population each where drinking water source has colour of 40-80 units. Also approx. 400 villages have been affected using these rivers as drinking water source and have to find alternative. b) The solid waste generated is lime sludge. This is indiscriminately being dumped around the factories polluting the land and water sources during monsoon months. c) Air pollution from these factories is very limited and affects only small population of the residential colonies of the factory employees as most of these paper mills are located in isolated areas from large cities.

52 POLLUTION CONTROL PRACTICIES The problem of air, water and solid waste pollution in pulp and paper industry in India are being tackled as follows: 1) Liquid effluents : Research institutes and other research universities have developed anaerobic digestion in which the black liquor or the Brown stock washev effluent is digested in an anaerobic lagoon with the detention period of 6 to 10 days. Generally abandoned mines or dry ravine beds are used for constructing these lagoons. The inlet and outlet arrangements are simple pipes with earthen embarkments. 2) Aerobic : Successful results have also been obtained by aerated lagoons for general paper machines wastes. The BOD reduction by both anaerobic and aerobic systems are up to 80-85%. 3) The rayon grade pulp effluent from sulphate process has also been treated successfully by anaerobic process using detention period of 12 days with 60% to 70% reduction in BOD and about 80% reduction in suspended solids. 4) Colour removal from board mill and straw board factories have been obtained by use of open field irrigation or through the run on grass fields. Reduction upto 60% have been recorded. 5) Small straw board factory : Black liquor disposal kas been successfully obtained by use of earthen drying beds. Black liquor volumes upto 150 mm can be dried within a period of 5 weeks during dry summer months. This gives area requirements of approx. 10 sq meters per thousand liter of effluent. 6) The disposal from the paper machine or board machine has also been tried successfully by land irrigation. Work has also been done on large mill with 200 ton/day successfully using experimental irrigation both on laboratory and on plot scale. The study showed that wheat or paddy can grow by the effluents successfully with the same yield as normal water irrigation. The results of irrigation for a period of 2 years have shown that approx. 25 ha. ' be irrigated per 20000 cue. meter of waste water for wheat and twice the amount for rice. These treatment disposal methods have been very successfully used in many pulp and paper mills in India but one aspect of removal of colour is still not solved.

53

DEVELOPMENT AND RESEARCH NEEDS In view of the difficulties experienced in India following may be considered for more effective treatment of paper mill effluent 1) Better separation of black liquor for this centrifuging or such similar methods may be adopted instead of blow tanks. 2) Lignin; recovery process may be developed to retrieve the available material for commercial value. Efforts have been made in many countries such as USA, USSR, to separate ligning from the black liquor by acidulation with H2SO4 and utilization of lignin. Ligning is also useful material for plastic industry and therefore further efforts should be made to develop chemical recovery process. 3) Use of fines rejected from the paper can be done by converting them into manure or soil conditioner by composing aerobically or by using it as fuel in steam generating boilers as pallets. 4) The lime sludge can be used for building construction as mortar or for manufacturing of cement. 5) Water use can be reduced up to 30% by introducing recycling. This may cover using paper machine water for stock making, lime hydrolyzing and smelt solving, floor washing etc. In small plants water consumption has been brought down from 270 cu. M / ton of paper to 200 cu. M/ton paper. MILL BOARD 50 T/DAY Typical characterstics of mill effluent at various place

Characteristics Mill Effluent after At mixing point effluent fiber recovery unit of river

Temperature M. °L 33 32 32

Conductivity (micro mhos/cm) 292 256 250

K 6.5 6.6 7.0

54 P-alkalinity as CaCO3 ppm Ni! Nil Nil

M-alkalinity as CaCO3 ppm 100 12 892

Suspened solids ppm 1000 400 50

Dissolved solids ppm 280 250 248

Chlorides as Cl- ppm 11.3 9.6 9.6

Oxygen absorbed (4 hrs) ppm 56 45 18

BODs at 20 degree cent. 70 50 30

COD ppm 629 214 106

Typical water pollution from a 10 Ton/day straw Board factory Raw Straw 28 T/DAY Source

Charecterstics Digestor Beater Board Combined discharge washer Machine effluent

Flow cu. M /day 85-90 370-400 370-400 455-500

Ph 11.0-11.2 8.6 7.7 9.3

Alkalinity mg/I (CaCO3) 40000 350 100.0 580

COD,mg/l 15,000 1650 540 1850

BOD mg/I 30,000 400 150 460 i

Total solids /mg/I 2,68,000 2100 1650 1250

Dissolved solids,mg/I 2,10, 000 1660 - 860

55 CHPTER 6 PERFORMANCE OF WASTE TREATMENT PLANT AT ORIENT PAPER MILLS, AMLAI (A CASE ST U BY) 1.0 Introduction Where is one of the main raw materials used in large quantities in the manufacturer of pulp and paper. The entire process right from the washing of the wood raw material to the drying of sheet of paper, water is required in one form im other form. It is estimated that 182 M6 to 450 MM of water are required to produce one ton of paper. As the end product is free from water, almost all water, which is consumed during the manufacturing process reappears as waste water. This waste water needs treatment before discharging into the natural water course. Orient Paper Mill, Amlai, is an integrated pulp and paper mill producing 200 tonnes of paper per day using sulphate process. The water consumption of this mill is 60,000 to 65,000 M per day and effluent discharge is 50,000 to 55,000 MM per day. The mill draws its water from the river Sone. The flow of the river Sone is about 2 lakh cubics at peak discharge to about 14 cubic* in the lean summer months. Except in summer months the effluent discharged into the river is much less than the normal flow of the river and there fore the effluent gets diluted and there is no real problem, but in summer months when the flow in the river is low, the waste water discharged from the mill may create Pollution problem and makes the river unfit for common use. Table no 1

Tolerance Limits for Industrial Effluent discharged in to Inland, Surface Water (I.S. 2490-1974)

Characterstics Tolerance limit

Total Suspended Solids mg/I Max 100

Ph 5.5-9.0 shall not exceed 40 degree C Ternprature

BOD : at 20 degree C/mg/I Max

Oil and grease mg/I Max 10

57 Phenolic Compounds mg/I Max 1.0

Cyanides as CN/mg/I Max 0.2

Sulphides as 5, mg/I Max 2.0

Radioactive Materials Alpha — emitters Max 10-9 Micro c/m Beta - emitters Max 10-8 Micro c/m

Insecticides nil

Total residual chlorine mg/I Max 1.00

Flourides as F mg/I Max 2.0

Bq, As,Cr,Cu,Pb,Hg,Ni,Sa,Ag,En not to exceed i.e. mg/I individually or collectively. COD ppm Max 250

Table no 2 Average charecterstics of individual and combined Waste waters

Slph, Section Flow (avg) Ph Total solids Suspended COD BOD Chlorides es M X 10 Cu/ mg/I solids mg/I mg/I mg/I Mg/ day mg/I

Chipper House 10.89 6.8-8.2 600-1000 400-600 400-590 35-70 30-40 42-1

Pulping (Cooking 5.0610-11.8 1600-2000 300-600 800-1700 270-400 40-80 74-1 and Washing)

Chlorination & 14.341.6-3.2 1900-2500 150-300 500-700 80-130 800-1400 35-6( Hypochlorite

Caustic 10.04 8.8-10.4 1100-1500 120-200 700-1600 130-200 200-285 40-8( Extraction

150- Paper machine 8.635.9-8.8 850-1600 500-850 460-800 -100-160 30-50 500

Grade II (2 + 3 + 5) 33.06 5.8-8.5 1100-2000 300-550 450-720 80-135 350-760 80-1'

Grade III (2 + 4) 16.07 9.8-11.0 1400-1900 200-440 800-1630 200-350 100-220 60-11

Lime Sludge 1.812.0-12.6 - 4.3%-10% - 30-40 Nil

2.0 Development of treatment facilities Effluent discharged from the process line contain organic matter ( soluble. & suspended) suspended solids, alkali and colour due to lignin and its derivatives. More over these effluent depleted of oxygen. The combined effect of these factors is the hazard to flora and fauna in the river in which the effluent is discharged. The laboratory studies were conducted and number of effluent samples were collected from various points and analysed for one year for various parameters viz. PH, BOD, COD, SS, Cl, SO4, Na, Hardness and colour etc. Based on these studies effluent from the mill segregated in three grades. Lab results are given in table no 2. Grade I — This consists of cooling water condensates and leakages from glands etc. It is practically uncontaminated water and hence collected and recycled in the mill at suitable point. Grade II — This effluent consist of white water from paper machine, chlorination and hypochlorite washing from bleach plant. Wash water from chipper house and supernatant of lime mud from causicizer plant also join this grade. Total volume of this grade is about 36,360 M3. Originally this is acidic in nature but after mixing lime sludge supernatant its Ph reaches to 7.0-8.0 range. Its BOD is about 100 ppm and suspended solids 400-800 ppm. Grade III — Comprise digester house leakages, wash liquors from pulp mills, and caustic extraction effluent from the bleach plant. It is dark brown in colour , highly alkaline ph 10-11, having BOD about 300 ppm and COD 1400 ppm. Its volume is about 16,000 M3 per day and suspended solids 300-400 ppm. On the basis of above studies, as shown that grade III is most contaminated effluent coming out from the mill. Lab experiments on the anaerobic treatment of this effluent where there-fore started using cow dung as a seed (to provide micro organism) and nutrients were supplied in the form of urea and superphosphate. The lab studies showed that at 15 days detention time reduction in BOD as high as 80% was achieved, while the reduction in COD was only 30%. The low reduction in COD was attributed to the non-

59 degradability of the lignin present in the waste water. Lab experiments were also started with aerobic treatment of the effluent using mechanical aerators. The results showed that in the presence of acclimatized activated sludge and nitrogen and phosphorous supplementation six hours of aeration period brought down BOD from 370 mg/l to 60 mg/1 and COD 2000 mg/1 to 755 mg/1. 3.0 Pilot Plant Studies and their significance On the basis of the lab studies, a pilot plant with capacity of 122.8 M~3 was started in which anaerobic treatment was given to grade III effluent. The plant attained optimum working with a 10 days detention period with in one year. The plant was run experimentally for one year at 10 days detention and a BOD reduction of 54-75% was achieved, the higher reduction being attained during summer months and lower reduction during winter months, PH was reduced from 10.5 to 8.2-8.5 range. Microbial activity in the plant was accelerated by adding nutrients (N&P) in the form of urea and sulphosphate at a ratio of 100:2:0.5 of BOD:N:P. After a year a new research programme was started on the Pilot plant. In this programme addition of nutrients was stopped and detention period was increased. Thus the Pilot Plant was operated for one year at 20 days detention period without any nutrients supplement. It was observed that the BOD reduction varied between 50 to 63%. This led to the conclusion that increasing the detention time may result in reducing the nutrient requirements to achieve the same levels of treatment. Since each set of studies incorporating various detention periods at various seasons of the year, different levels of nutrients at anaerobic Pilot Plant take a minimum of the one year for any standards and definitive results, it is obvious that Pilot Plant studies take much longer time than lab studies. 4.0 Intersize lagoon (ISL) studies and their significance When Pilot Plant investigations gave encouraging results it was next programme to carry the findings to a intersize scale, before going for mill scale. One ISL was put in operation having capacity of about 9,100 M3. Anarerobic treatment studies were started by running the lagoon at 50 days detention of grade III effluent for four months. This lagoon was seeded with 91 IVf (i.e. 1%) of cow dung. Average reduction in BOD was about 60% and the ph was reduced from 10.5 to 8.2-8.7 range. Nutrients (N:P) were added in the ratio of 100:2:0.5 of BOD:N:P on a continuous basis. The inter size lagoon was run at different detention period to study the effect of various detention time. As programmed the detention time was progressively reduced from 50 to 15 days. It was found that BOD reduction of 66% could be obtained even at 20 days detention time in summer months. Pilot Plant and inter size lagoon investigations led to the conclusion that Grade III waste as such or after Ph adjustment with chlorination effluent to 8.0 can be treated an aerobically in a lagoon. On this basis lagoon no 1 with a capacity of nearly 3,63,700 M3 was taken up for an aerobic treatment of grade III effluent. 5.0 Aerated lagoon Pilot Plant studies and their significance A quicker alternative to an aerobic treatment to induct oxygen into the mill effluent is to practice aerobic treatment in which oxygen is introduced by mechanical means.. To get some idea on this method research work on aerobic treatment of grade III effluent was started. An aerated lagoon Pilot Plant with a capacity of 75,000 gallons was installed. Grade III effluent contents in the tank were aerated with the help of a floating aerator of 5 H.P. and 3 feet diameter. Liquid depth in the tank was 8 feet. Nutrients (N&P) were added in the ratio of 100:5:1 of BOD:N:P. Experiments were conducted for four years to study the effect of various detention period, level of nutrients and the total time of aeration etc. to work out a more efficient aerobic treatment. In Pilot aeration tank 80-85% BOD reduction and 40-50% COD reductions were achieved at 4 days retention time. On the basis of Pilot aeration tank experiments the mill has installed a large scale aeration pond for treating an aerobically treated grade III effluent. 6.0 Research Project on Grade II effluent Grade II effluent is less contaminated than Grade III effluent as regards to BOD, COD and other chemical constituents, but it contains lot of suspended solids. Lab experiments were therefore, started to study the sedimentation behavior of the composite grade II

effluent. Experiment had shown that in 1/2 - 1, hrs simple sedimentation there was 90% suspended solids reduction and consequently 30% BOD reduction. Based on this research

61 a clarify flocdulator of 156 feet diameter has been constructed for SS removal of grade II effluent. Further research work on aerobic treatment of clarified grades II effluent was conducted, where 75% BOD and 50% COD reduction in 4 days detention period. Grade II effluent The treatment system for grade II consists of clani flocculation followed by aeration lagoon. Grade II effluent is first treated in a clari floculator to remove suspended solids and floating materials. The sludge from clari floculator is collected in a sump well and is pumped into two settling ponds, used alternately partial drying. Finally sludge is manually removed from the ponds and disposed as land fill. About 9,000 M3 of this clarified effluent is being recycled in the mill for bamboo transportation and chip washing and rest is taken to aeration pond for further treatment to reduce BOD and COD of the effluent. After this treatment Grade II effluent confirm US 2490-1974, Part I(limits for the discharge of industrial effluent in to land surface water). The design features of the clariflocculator and aeration ponds are as below: A. Clariflocculator design 3 Criteria-volume of waste water 36x10 M3/d (8 MGD) Diameter of clariflocculator 47.55 M (156 feet) Inner flocculating chamber diameter 15.93 M (52.25 feet) Side water depth 3.05 M (101 feet) Weir over flow rate 253.5 M3/d/linear Meter ( 17000 gal/d linear feet) (at 36x

3 10 M3/d/waste water flow Detention time 45 min in flocculat- ing chamber 3.5 hrs

62 in the clarification zone for the avg flow of 36 x

3 10 M3/d Volume of sludge 727 M3/d (1,60,000 gal/d) Solid cone in the sludge 2.0% Suspended solid removal 90% B. Areated lagoons design criteria: Total volume of aerated lagoons 153x 103M3 (5.4 x 10 6 cft) Depth of lagoons 3.2M+/-0.08m (10.5+1- 0.25 feet) Detention time 4.2 days for an avg flow of36x103M3/d Number of aerators(EIMCO-KCP surface 6 (six) are used) Total horse power 135 HP (5X25 HP + lxlO HP) Oxygenation capacity 1.59 Kg oxygen/HP/hr ( 3.5 lbs, oxygen/HP/hr) Total oxygen transfer anticipated 205 Kg/hr (450 lb/hr) (95% of rated capacity) BOD removal 70% COD removal 45%

63 7.0 Grade III effluent This effluent is highly alkaline (PH 10-11) hence it is mixed with 2,273 M-4546 MM (0.5-1.0 million gallons) of chlorination effluent (PH 1.5-3.5) to lower the PH in the range of 8.0-8.5. The mixed effluent is settled in earthen lagoons to remove suspended solids. Two lagoons, each of about 9150 M3 capacity are used alternately. The settled sludge is manually removed and disposed off for land filling. A clarflocculator of 120 feet diameter is under construction for settling of grade III waste. The settled waste water is treated an aerobically in lagoon no 1 for BOD and COD removal. Initially the lagoon was seeded with actively fermenting cow dung slurry and the seed was acclimatized to grade III effluent by increasing the load in stages. The total quantity of grade III waste taken the an aerobic lagoon. Nutrients (N&P) are being added regularly in the ratio of 100:2:0.5 of BOD:N:P. In order to bring down BOD to 30 mg/l, the an aerobically treated effluent is further treated in aeration pond, with the addition of nutrients in the ratio of 100:5:1 of BOD : N : P. Before discharging in to the river, the aerated grade III effluent is detained in publishing pond for 15 days to settle out any biological' mass developed during aerobic treatment and given sufficient time to complete some oxidation reactions, which further reduces BOD effluent by about 15% polishing pond covers about 14.4 hectares area, with a storage capacity of 0.25 x 10 6 m3. The design features of an aerobic and aerobic ponds are as below :- An aerobic Lagoon design criteria :-

6 3 Capacity 0.386 x 10 M (85 MG) (with an area of 13.4 hectaers)

Water depth 1 m to 10 m

Detention Time 20 days

Flow (effluent) 18,200 M 3 /day

BOD reduction 50% Aerated Lagoons (Grade III) design criteria :-

33 6

Total volume of the lagoon 85 xlOM(3xlOcft)

Depth of areation pond 2.74 meter

No. of areators(EIMCO-KCP) 10

Total horse power 115(1 x25 HP+9x10 HP)

Total oxygen transfer 182 KG oxygen/hr (400 lb 02/hr)

Detention time 4.5 days for an avg flow of 18.2 x 10 3 M3/day

BOD reduction 60%

COD reduction 30%

Utilization of Grade III effluent The treatment methods described above reduces SS, BOD, COD of the effluent, but the colour remains unchanged. It is because colour in grade III waste is due to lignin and its compounds which are biologically resistant. Though colour is an aesthetic pollution, even its presence makes the water disagreable. And there is no economical method known for removal for colour of grade III effluent. With this object in view the mill has started land disposal of grade III effluent for irrigating eucalyptus plantation around the mill. At present about 6000 M 1 — 9000 M of grade III waste used for irrigating eucalyptus plantation covering an area of about 80 hectares.

65 8.0 Performance of Treatment Units To evaluate the working efficiency of different treatment devices three years, operational data have been collected. These data have been analysed with respect to the designed capacity of the unit, mill process condition and other environmental conditions. Table 1 Performance of grade II, Clariflocculator and Oxidation pond during 1978-81

Out let to clariflo- Present In let to clariflo- cculator (i.e. inlet Present reduction Outlet to oxid- reduction to oxidation Month/Year Flow M3/day cculator pond) (clariflocculator) ation pond (oxidation BOD COD SS BOD COD SS BOD COD SS BOD COD SS BOD CO[

1978

April 30000 82 450 450 45 292 88 45.10 35.1 82.22

May 31822 80 500 600 55 300 40 31.25 40.00 93.33

June 34095 70 440 480 50 280 60 28.57 36.36 87.50

July 35913 90 520 500 53 292 87 41.11 43.85 82.60

August 31975 82 500. 400 45 194 52 45.10 61.20 87.00

Sept. 31800 88 508 397 47 246 47 46.60 51.57 87.00

Oct. 31822 97 488 370 45 325 45 53.60 33.40 88.00

Nov. 35913 94 520 480 48 300 48 48.93 45.52 90.00

1979

April & May 30000 85 361 459 51 230 49 40.00 36.3 89.32 24 - 118 39 53.7 48.'

June 30800 66 303 369 47 195 49 28.79 35.6 86.72 23 170 38 51.1 12.

July 32000 50 435 363 46 234 54 8.00 46.20 85.12 20 200 50 56.5 17

August 28500 68 463 476 50 278 58 26.47 40.00 87.82 17 121 39 66 56.

Sept. 34095 70 336 436 47 256 53 32.86 23.80 87.84 16 125 41 66 51.;

Oct. 31822 70 375 500 44 - 240 53 37.14 36.00 89.40 14 155 45 68.2 40

Nov. 29700 87 508 430 45 288 50 48.28 43.30 90.23 18 162 37 61 43.E

Dec. 28400 92 624 423 52 316 53 43.48 49.36 87.47 18 178 35 65.3 43.

Table 2 Performance of Grade-2, Clariflocculator and oxidation pond during 1980-1981

Out let to clariflo- In let to ciariflo- cculator (i.e. inlet Present reduction Outlet to oxid- Present re Month/Year Flow M3/day cculator to oxidation pond) (clariflocculator) ation pond (oxidation BOD COD SS BOD- COD SS BOD COD SS BOD COD SS BOD CO[

1980

January 31822 95 601 367 43 298 44 54.74 50.44 88.01 17 172 36 60.47 42.

Feb. 29800 87 567 382 45 300 45 48.28 47.10 88.22 17 169 33 61.22 43.

March 31000 92 508 430 59 288 42 35.87 43.30 90.23 21 162 34 64.41 43.

April 28412 70 480 450 60 280 50 15.17 41.67 88.89 22 192 35 63.32 31.

May/June 28200 105 436 756 62 290 47 40.95 33.50 93.78 21 188 60 66.13 35.

July 28400 90 525 525 66 278 45 26.67 47.05 91.43 17 151 65 74.24 45.

Aug. 34550 12 460 570 78 234 51 35.00 49.10 91.05 45 132 50 42.31 43.

Sept. 34095 97 434 440 65 268 48 33.00 38.20 89.00 16 117 41 75.36 56.

67 Oct. 31850 94 463 623 68 205 45 27.66 55.70 92.78 14 94 40 79.41 54.

Nov. 40000 104 551 617 73 200 40 29.81 63.70 93.52 22 102 37 69.86 49.

Dec. 35300 114 614 612 64 298 50 44.00 51.40 91.80 25 144 29 61.00 51.

1981

January 32276 97 472 518 61 194 47 37.11 58.90 90.93 24 150 32 60.00 22.

Feb. 35790 88 494 500 60 195 44 31.82 60.50 91.20 23 165 30 61.67 15.

March 35790 11 422 426 55 191 42 50.00 54.71 90'.14 20 152 35 64.00 20.

Table 3 Performance of Aeration pond and polishing pond for grade III In let to Aerat- Out let to Aerat- ion (I.e. out let to ion pond (or inlet Present reduction Outlet to polis- Present reduction Month/Year Anerobic lagoon) to polishing pond) in aeration pond hing pond (in polishing pond, GOD COD SS BOD COD SS BOD COD SS BOD COD SS BOD COD SS

1980

April 160 1085 100 100 906 90 37.50 16.50 10.00 75 732 70 25.00 19.20 22.2

May&June 155 951 90 105 765 80 32.26 19.57 11.11 78 727 76 25.71 5.00 5.0(

July 182 995 98 106 790 100 41.67 20.62 0.00 90 741 88 15.10 6.20 12.0

Aug. 196 950 108 105 780 90 46.43 17.90 0.00 plant shut

Sept. 180 804 100 108 680 95 40.00 15.42 5.00 87 570 90 19.44 16.16 5.2E

Oct. 220 923 90 110 720 105 50.00 22.00 0.00 91 630 65 17.27 12.50 38.1

Nov. 217 1000 95 132 844 105 39.17 15.60 0.00 99 677 70 25.00 19.78 33.3

Dec. 224 1090 156 137 888 105 38.84 18.53 32.69 95 862 91 30.66 2.92 13.3 1981

January 295 1383 152 190 1108 123 35.59 20.00 19.08 156 1103 85 18.00 0.40 30.85

Feb. 385 1552 108 290 1359 86 24.67 12.43 20.37 172 1200 59 40.66 11.70 31.41

March 263 1063 104 186 953 87 29.28 10.60 16.35 171 900 73 8.06 5.55 16.0!

Table 4 Performance Anaerobic lagoon for grade III during 1978-81

Flow In let to Out let to Present reduction Month/Year m 3/day Anerobic lagoon) Anerobic lagoon) BOD COD SS BOD COD SS BOD COD SS

1978

April 18184 290 1258 225 195 1050 85 32.76 16.53 62.22 May 19548 317 1230 227 186 917 92 41.32 25.44 59.47 June 22276 270 1272 213 156 900 88 42.22 29.24 58.69 July 20450 200 1122 220 71 800 150 64.50 28.70 31.82 Aug 17140 183 1122 208 98 750 82 46.45 33.15 60.58 Sept 19548 223 1322 204 115 757 90 48.43 42.73 55.88 Oct 19093 283 1250 200 160 996 88 41.70 20.32 56.00 Nov 18640 254 1250 196 160 900 90 37.01 28.00 54.08 1979

May 14775 250 1011 192 150 880 90 40.00 13.00 53.13 June 17047 227 1140 192 140 950 90 38.33 16.67 53.13 July 17040 210 1308 192 125 1050 88 40.48 19.72 54.17 Aug 17000 209 1200 197 110 900 92 47.37 25.00 53.30 Sept 19900 172 863 190 100 740 95 41.86 14.25 50.00 Oct 21366 181 872 185 100 750 92 44.75 14.00 50.27 Nov 19093 216 1016 140 115 850 80 46.76 16.34 42.86 Dec 19680 195 1063 146 125 850 80 35.90 20.00 45.21

1980 Jan 19093 224 1016 170 170 880 90 24.11 13.38 47.06 Feb 19548 205 1040 166 153 881 85 25.37 15.40 48.80 March 17545 257 1146 170 155 774 94 39.69 32.46 44.71 April 16130 270 1350 160 160 1085 100 40.74 19.63 37.50 May&June 17950 258 1310 178 155 951 90 40.33 27.40 49.44 July 17047 316 1463 204 182 995 98 42.40 32.00 52.00 Aug 17280 400 1350 250 196 950 108 51.00 29.62 57.00 Sept 18184 308 918 260 180 804 100 41.56 12.42 61.53 Oct 15911 383 1387 261 220 923 90 42.18 33.44 65.50 Nov 18184 400 1172 222 217 1000 95 45.75 14.67 57.20 Dec 15000 354 1470 242 224 1090 156 36.72 25.85 35.54

1981 Jan 17500 346 1544 263 295 1388 152 14.74 10.43 42.21 Feb 13638 476 1950 255 385 1-552 108 19.12 20.41 57.65 March 17195 377 1257 216 263 1063 104 30.24 15.02 51.85

9.0 Cost Mill has spent about 87 lacs of rupees on construction of various effluent treatment works described above and expected to spend another 15 lacs rupees on balance treatment work, such as clariflocculator of grade III effluent and lime sludge settling pond at river side. The recurring annual cost on running and maintenance of the various effluent works including expenditure on nutrients, power and salaries etc. is about 8 lacs rupees. Apart from this mill has established a research institute for various type of research on pulp and paper, which contain a separate wing for effluent treatment. Various types of research are being conducted here on the treatment and utilization of pulp and paper mill waste water. Expenditure on research is an addition to above.

70 CWAPTER 7 The Application of the Rapson-Reeve Closed-Cycle Concept at Great Lakes Forest Products, Thunder Bay, Ontario Prior to its implementation at the new Great Lakes Forest Products bleached kraft pulp mill had been the subject of many papers and discussions in the industry dating back to about 1967. It was at this time that Dr. Howard Rapson, Professor of Chemical Engineering at the university of Toronto had first proposed the idea. 1.0 DESCRIPTION OF THE CONCEPT The concept of the closed cycle system is dependent on making a number of major changes in the operation of the unbleached washing and screening, the bleaching system and kraft recovery system. While the concept was certainly the sole product of Dr. Rapson's imagination, in the final stages there were a number of persons involved in developing the design information which allowed the process to become a practical reality. The following are some major concepts of the system: 1. Reduction in water usage in many areas of the mill, particularly in the screening system and the bleach plant. 2. Complete countercurrent recycle of bleachery process streams, i.e. D2 to D1 to C/D and E2 to El with El and C/D stages effluents mixed, ph adjusted, and use as wash water on the unbleached pulp. This sequence was subsequently modified. 3. The first bleaching stage, which is normally almost 100% C12, uses a 70/30 mixture of C102/Cl2 (based on chlorine bleaching equivalent) serial application. 4. The "white" or cooking liquor, (a mixture of sodium hydroxide (NaOH), containing a significant amount of sodium chloride (NaCI) is evaporated until the NaCI crystallizes and is removed by filtration. 5. Steam stripping of foul evaporators condensates is employed. 2.0 MILL DESIGN Some quite different parameters from a conventional mill were used in the final design of the mill. Some of these are:

71

1. Major increases in internal tank age were necessary to accommodate surges thus eliminating spills. 2. Corrosion was anticipated as a problem in the D/C, Dl and D2 washers where a new more corrosion resistant material was used. Table 1 shows the details of these materials of consustuction.

Table 1 Bleach plant materials construction

Surge D/C El & E2 D1 & D2 Bleached Equipment Tank Decker

Washer Drums 317 Avesta 316 Avesta 316 254 SLX 254 SLX

Stock Lines 317 FRP 316 FRP 316

Pumps 317 317 316 317 316

Tank inserts 316 Ti & 316 317 316 FRP Steam Mixer - - 316 317 -

Chemical Mixer - FRP - FRP -

Note : Towers: Steel, Tile-lined Washer vats: Tile Seal Tanks: FRP (Fiber glass Reinforced Plastic) AVESTA SLX refers to patented corrosion resistant alloy. 3. Because of the high chlorine — dioxide usage, two 14 T/day C102 generators installed using the ERCO R-3 process.

72 The R-3 process is described chemically by the following reaction: NaC1O3+NaC1+H2SO4 = C102+C12+H20+Na2SO4 The process uses a silver nitrate catalyst, and the sodium sulphate produced as a by product is used as make up chemical in the kraft recovery system. 4. Numerous spill tanks with manual/automatic systems were used to recover spills. 5. In the final design, after discovering that calsium deposition and organic precipitation would likely be a problem, the countercurrent bleaching sequance was altered to: D2 to E2 to D 1 to (El and D/C) In other words, the D1 effluent was used in both the El and D/C showers. In the following descriptions it should be borne in mind that the mill complex at Great Lakes contains two bleached kraft mills, and comparisons can be made with the `A' mill which operates conventionally, while the `B' mill operates on the closed- cycle system. 3.0 PULPING AND BLEACHING OPERATION Extensive training of mill operational staff was a pre requisite to operating the mill under tight control. The process was closely monitored by the technical staff to ensure the problems were discovered before they become significant, and began to `domino' throughout the system. With the extensive recycle the low level fresh water usage, higher process temperatures were encountered, but these have not caused any particular concern in the working environment. Increased scaling was anticipated, particularly in the continuous digester, but this has not occurred. In fact, scaling is actually less in this mill than in the associated mill operating on the same raw materials. Neither unbleached pulp yield nor quality has been affected one way or the other by the closed cycle process. There has been no apparent differences in the quality of the bleached except a significantly lower viscosity drop through the bleach plant with the closed cycle process. Other design parameters may have caused this so this benefit is not claimed directly as aresult of the closed cycle operation. Approximately 11% more bleaching chemical (chlorine equivalent) is consumed in the bleachery than under conventional operating conditions due to higher carry over of organics from the unbleached washers.

73 1.0 BLACK LIQUOR RECOVERY AND EVAPORATORS OPERATION The most serious problem with the closed cycle operation occurred in this area. Corrosion of the recovery boiler super heater caused tube failure and for a period of time, led to discontinuation of closed cycle operations. This will be described later in the section under corrosion. It was further found that there was an average of 6.5% reduction in black liquor heating value, and a slightly lower % solids in the liquor fired to the furnace due to liquor not picking up well on the tubes of the cascade evaporator. Because of this, gas fuel make up to the recovery furnace has been required to maintain combustion, at a rate of about 650 lbs/hr: Total solids flow adjusted for the dead load of sodium chloride is slightly higher than in a conventional mill as would be expected due to the inclusion of bleachery organics. 2.0 RECASTICIZING AND LIME KL T OPERATION No significant changes have been noted in either the recausticizing and lime klin operations. 3.0 EQUIPEMENT CORROSION Equipment corrosion has been found in several areas as follows:

1. Salt Recovery Unit a) tubes in first effect heater. Original INCONEL 600 has been replaced by E-Brite 26-1. b) Tubes in the caustallizer heater have failed due to vapour side pitting. The cause is being investigated.

2. D2 Pulp washer Original 317 ELC stainless encountered corrosion and was interchanged with a brown decker of AVESTA 254 SLX. 3. Bottom of D/C Bleaching tower The stock line insert, and the tower agitator insert, both 317 ELC, had to be replaced. The stock line insert is now titanium and the agitator insert is FRP.

4. Recovery Flue Gas Precipitator Corrosion was severe even before closed cycle operation began. The flue gas temperature entering the precipitator was raised and subsequently corrosion has been minimal.

74 5. Recovery Boiler Super heater Corrosion By far the most serious problem in the mill has been corrosion of the part of final section of the recovery boiler superheater. The leading side of the final section has shown the most corrosion, as well as on the inside corner of the tube bends. Following mill trials with different samples on a probe in the super heater section, a section of the super heater has been replaced with Incoloy 800 alloy. More replacements are scheduled as shut down time permit. Increasing the amount of closure of the water cycle is being held up pending the evaluation of the performance of this alloy. 6.General mill corrosion Other than the specific areas mentioned above, corrosion has not been abnormal throughout the mill. Special precautions were taken in specific areas e.g. the D/C stage and D1 stage pulp washers were ordered in AVESTA 254 SLX alloy to withstand the higher chloride and temperature levels, but generally conventional materials of construction have stood up well to date through out the kraft mill complex. 4.0 MILL EFFLUENT CHARACTERSTICS The purpose of all of the foregoing was, of course, to eliminate the necessity of treating the mill effluent to a quality acceptable to government requirements. During the initial trials with full closu, BOD5 discharges reached about 15 lbs/ton (7.5 kg/tonne) vs a normal kraft mill at about 80 lbs BOD/ton (40 kg/tonne). The discharges are about double at 30.8 lb/ton(1 5.4 kg/tonne). A breakdown of the discharges are given in Table no 2. It must be recognized that this data has been obtained during a period when the system was not completely closed. If one were to speculate that the entire bleachery effluent was being utilized, the BOD discharge would be approximately halved (actual reduction 45%) to 16.8 lbs (8.20 kg) BOD/ton. No satisfactory point has been found to utilize the treated stripped condensate and excess sextuple evaporator condensate in the closed cycle system.

75 TABLE NO 2

Streams Flow BOD5 Suspended Solids Dissolved Solids US(GPM) USG PER LBS/DAY LB PER TONS/ LB PER TONS/ LB PER BL. ADT BL. ADT DAY BL. ACT DAY BL. ADT

1. "B" Fiber Sewer 1,377 2,767 2,972 4.16 1.6 4.47 5.9 16.5

2. Clean Water outfall 9,309 18,711 1,863 2.6 1.7 4.75 23.8. 66.5

3. DIG Bleed 268 538 4,320 6.40 N.T. N.T. 21.2 59.3

4. El Bleed 305 613 5,740 8.02 N.T. N.T. 31.2 87.2

5. E1+BI. Spill Pit N.T. N.T. N.T. N.T. N.T. N.T. N.T. N.T. Over Flow

6. D/C + Br. Dkr. N.T. N.T. N.T. N.T. N.T. N;T. N.T. N.T. Spill Pit Over Flow

7. Treated Stripper - - 4,320 5.9 N.T. N.T. N.T. N.T. Condensate

8.Excess Sextuple 285 572 2,930 4.09 N.T. N.T. N.T. N.T.

TOTAL 11.544 23.203 22.055 30.8 3.3 9.22 82.1 230

5.0 COST OF THE CLOSED CYCLE SYSTEM of course, we must get to the bottom line of this whole endeavour, namely the cost of this operation. No attempts have been made to determine capital costs of this mill as a conventional mill. Sufficient to say that the cost was about $ 220,000 / daily air dry tonne of bleached kraft pulp (1976 dollars). The extra in-plant operating costs for the closed — cycle system have been compared only to a similar, modern kraft mill without the closed cycle bleaching and salt recovery system, but which already has inplant effluent reduction techniques such as:

76 - a closed screening system, - spill recovery and control, - steam stripping of foul evaporator condensates and turpentine decant, and - closed recausticizing and kiln areas The variables compared were : a) steam production, b) steam consumption, c) bleach chemical consumption, d) salt production, e) defog~mer use, f) treated water consumption, g) operating cost of SRP plant, h) increased cost of using chlorine dioxide in place of chlorine in the first bleaching stage. The results of this comparation are shown in Table no 3. TABLE NO 3 OPERATIONAL COST OF THE CLOSED — CYCLE PROCESS (Based on 1979 operating data)

Net benefit (+) or cost (-) as a result Variable of closed cycle operation $ per bleached air dry ton

1. Steam production + $ 1.28 2. Steam consumption - $ 2.29 3. Bleaching chemical consumption - $ 5.52 4. Salt production + $ 1.40 5. Extra deformer consumption - $ 0.97 6.Treated water consumption + $ 0.04 7. Operating cost of SRP plant - $ 0.49 (exclusive of steam cost)

77 8. Increased cost of using chlorine - $ 1.14

OVER ALL NET COST $ 7.69

The above costs were assessed when the system was only partially closed. It must be assumed that certain heating cost would be higher in a conventional mill. The over all operating cost of the closed bleaching and salt recovery plant is shown to be $ 7.69 per tonne of bleached pulp. In another paper it has been 'stated that the bleached pulp yield could be higher ( approx. 1.6%) with high substitution of the chlorine dioxide for chlorine in the first stage.

The benefit of the higher yield is calculated as follows : a) 1.6% yield x 648 air dry tons per day = 10.3 tonnes per day extra pulp production. b) Since this extra 10.3 tonnes has to be bleached, dried, and stripped, the variable cost of these three operations must be substracted from the selling price of pulp. This is estimated to be $ 100 per tonne. ( the actual figure will not be released due to the private nature of the operations, but this figure serves as a `ballpark' estimate to give a cost comparison. Actual figures may be substituted for different case.) c) Selling price of pulp- + $465 US per metric tonne (Pulp and Paper Magzine, Oct 1979, p- 11) $465 x 2000/2200 x $1.18 Canadian /$1 US = $548 per tonne $ Can. High substitution of chlorine dioxide for chlorine can be made independently of closed cycle operation and there fore, any potential benefit of the higher yield can not be claimed as a benefit of `closed cycle' operation. There fore, the overall net cost of operating the closed cycle mill, assuming an increase in bleached yield of 1.6% because of the 70-30 D/C stage , is $ 7.69- $6.96 = $0.63 per air dry tonne of fully bleached pulp. This would only be valid for a mill which did not use 70% C102 substitution in the chlorination stage before implementing the closed cycle process. However, if the mill is already using 70% C102 in the chlorination stage the increased cost by going on closed cycle would be $7.69-$1.14 = $6.55 per air dry tonne. ~t is estimated that to opertate a secondary treatment lagoon would cost up to $6/AD tonne( 1978 $Canadian) While one can not say that the present operation of the closed cycle mill has been 100% successful in fully recycling all process streams it can certainly be stated that the concept is proven and viable. The difficulties which one encounters in controlling a process of this size and complexity is difficult enough without adding to the problem by the necessity of balancing numerous flows. It is credit to this company that they have almost fulfill these demands.

79 CHEPTER 8 ENVIRONMENTAL MANAGEMENT IN INDIA 1.0 HISTORICAL PERSPECTIVE In India, the issue of protection of the environment and sustainable use of natural resources, received due attention in the planning process in the early seventies. The fourth five year plan (1968-73) gave explicit recognition for integrating environmental dimensions into the planning and development processes. The committee on Human Environment was set up in 1970, by the government of India under the chairmanship of Shri Pitamber Pant, Member, Planning Commission, to prepare a Country Report for the UN Conference on Human Environment. A National Committee on Environmental Planning and Coordination (NCEPC) was set up in February 1972, in response to the Pant Committee recommendations. The NCEPC continued to be an apex advisory body for a quite period of time, in all issues concerned with protection of the environment and its improvement. On the basis of the recommendations of Tiwari Committee, the Government of India constituted a separate Department of Environment (DOE) effective from November 1, 1980 to be the center stage for planning, promoting and coordinating programmes related to the environment. Subsequently, a full fleged Ministry of Environment and Forests was constituted in 1985, to oversee the functions at the national level.

:• 2.0gNVIRONMENTAL LEGISLEATIVE NETWORK Name of agency Key Function Ministry of Environment -Environmental policy planning and Forests -Ensure effective implementation of legislation -Monitoring and control of pollution -Boo development -Environmental clearances for Industrial and Development projects -Environmental research -Promotion of the Environmental education, training and awareness -Coordination with concerned agencies at the national and international levels -Forest conservation, development and wildlife protection -Biosphere reserve programme Central Pollution Control -Promote cleanliness of streams and wells Board -Advise the Central Government on the matter concerning prevention, control and abatement of Water and Air pollution -Co-ordinate and provide technical and research assistance to State Boards -Information dissemination, training and awarness -Lay down, modify or annul the standards for a stream or well, and for air quality -Planning and execution of nation wide programmes for the prevention , control or abatement of Water and Air pollution -Ensure compliance with the provisions of the Environmental (Protection) Act 1986. -Planning and execution of state wide programmes for State Pollution Control the prevention, control or abatement of Water and Air Boards pollution -Advise the State Government on prevention, control and abatement of water and air pollution and siting of industries -Information dissemination, training and awareness -Ensure compliance with the provisions of the relevant Acts -Lay down, modify or annual the effluent and emission standards -Ensure legal action against defaulters -Evolve techno — economic methods for treatment, disposal and utilization of the effluent. Organisational structure for Environmental Management in India

3.0 ENVIRONMENTAL LEGISLATION IN INDIA • The water (Prevention and control of pollution) Act, 1974, as amended up to 1988 • The water (Prevention and control pollution) Rules, 1975 • The water (Prevention and control of pollution) Cess Act 1977 as amended up to 1991 • The water (Prevention and control pollution) Cess Rules 1978 as amended up to 1992 • The Air (Prevention and control of pollution) Act 1981, as amended up to 1987 • The Air (Prevention and control of pollution) Rules 1982 and 1983 • The Environment (Protection) Act, 1986 • The Environment (Protection) Rules, 1986 • The Hazardous Wastes (Management and Handling) Rules, 1989 • Manufacture, storage and import of Hazardous Chemical Rules, 1989 • Manufacture, use, import, export and storage of Hazardous Micro-Organism, Genetically engineered Micro-Organisms or Cells rules, 1989 • The public liability insurance act, 1991 • The public liability insurance rules 1991 • Environmental (Protection) Rules, 1993 `Environmental Standards' • Environmental (Protection) Rules, 1994 'Environmental clearance' 4.0 Environment Legislation for Industry and Business

Environment Legislation Provision Concerning Industry and Business The water(prevention and i) Polluion control board (PCB) has right: control of polluti-on), - To obtain any information regarding the Act, 1974, incudi- ng construction, installation or operation of an Rules, 1975 industrial establishment or treatment and disposal (An act to provide for the system prevention and control of - To take samples of trade effluent for the purpose of water pollution and analysis in the prescribrd manner maint- aining or restoring - To enter and inspect any industrial establishment, whole someness of water.) record, register, document or any other material object. - To prohibit use of stream or sewer or land for disposal of polluting matter, not in accordance with the standards laid down by the PCB. ii) Restriction on establishment and the operation of an industry, process or any treatment and disposal system with out prior consent of the PCB iii) PCB's right to refuse or withdraw consent, for discharge of effluents. iv) Industry to comply with the conditions stipulated in the consent v) PCB's to grant consent with in 4 months after the date of the receipt of the application complete in all respects vi) Industry to appeal to the Appellate Authority, in case of grievances against the order passed by the PCB regarding grant, refusal or withdraw of

LsZ the consent with in the specific time in the prescribed manner. vii) Industry to furnish information to the PCB and other specified agency in case of discharge of poisonous, noxious or polluting matter into a stream, sewer or land, occurred or likely to occur resulting in pollution due to an accident or any other unforeseen event. viii) PCB's right to issue orders restraining or prohibiting an industry from discharging any poisonous, noxious or polluting matter in case of emergencies, warranting immediate action. ix) PCB's power to make an application to the court for restraining apprehended pollution of water due to likely disposal of polluting matter in a stream or on land. x) Bar of jurisdiction to civil court in respect of any matter under purview of the Appellate Authority constituted under the Act and no grant of injunction in respect of any action taken or proposed in pursuance of the Act. xi) Bar on filing of any suit or legal proceeding against the Government or Board officials, for action taken in good faith in pursuance of the Act xii) PCB's to make inquiries, in the prescribed manner, for grant of consent for discharge of the effluents. xiii) PCB's power to issue directions for - the Clouser, prohibition or regulation of any industry, operation or process or - the stoppage or regulation of supply of electricity,

s.4 water or any other service to industry in the prescribed manner xiv) Industry to comply with the directions of the PCB within the specified time xv) PCB's to maintain a consent register containing particulars of the consent issued and to provide access to industry at all reasonable hours. Environment Legislation Provision Concerning Industry and Business The water (Prevention and i) Only specified industry sectors to pay cess on the control of polluti- quantity of water consumed for specific purposes on) Cess Act 1977, at prescribed rates. including Rules 1978 ii) Any specified industry liable to pay water cess: An act to providep for the - to affix meters of prescribedp sstandards ds aand d at levy and collection of a prescribed places by PCB's for measurement of cess on water consumed quantity of water consumed by persons carrying on - to furnish water cess returns in the prescribed form certain industries and by at prescribed intervals local authorities to - to pay interest for delay in payment of cess, not augment resources for the made within the specified time, as mentioned in the Pollution Control Board. Assessment Order of the PCB - to pay penalty not exceeding the amount of cess in arrears, for non payment of cess within the specified time as mentioned in the Assessment Order of PCB iii) Specified industries entitled to 25% rebate in water cess, if they comply with the prescribed consent provisions and consume a quantity of water which is not in excess of the prescribed quantity iv) PCB's right to make inquries for assessing water cess payble by any specified industry. v) PCB's right to recover any amount due under this act as arrears of land revenue from industry. vi) PCB's right to entry and inspection to carry out provisions of the act including the testing of correctness of the meters affixed. vii) Industry to appeal to Appellate authority in case of any grievance against the .water cess

:: assessment, within the specified time, in the prescribed manner.

Environment Legislation Provision Concerning Industry and Business The air ( Prevention and i) State Government's powers include: control of pollution ) act, - to declare any area within the state as an Air 1981, including Rules Pollution Control Area 1982 and 1983 - to prohibit use of any fuel or burning of any material ( An act providing for which may cause air pollution in the Air Pollution prevention, control and Control Area abatement of air pollution ii) restriction on establishment and operation of any industrisl plant in an air pollution control area likely to emit air pollutant into the atmosphere, without the prior consent of the Pollution Control Board. iii) PCB's to make inquries in respect of grant of consent in prescribed manner iv) PCB's to grant consent within 4 months after the date of the receipt of an application complete in all respects. v) Restriction on emission of air pollutants in excess of the standards prescribed by PCB's vi) PCB's right to make an application to the court for restraining an industrial plant, located in an air pollution control area, likely to emit air pollutants in excess of the prescribed standards. vii) Industry to furnish information to the PCB's and any other agency in case of emission of air pollutant in excess of prescribed standards, occurred or likely to occur, resulting in air pollution, due to an accident or an unforeseen act or event. viii) Industry to comply with the conditions stipulated in the consent. ix) PCB's rights include: - to enter and inspect any industrial plant, records, registers, or documents at all reasonable times. - To obtain any information related with the implementation of the provisions of the act. - To take samples of air and emissions for analysis in the prescribed manner. x) Industry to appeal to the Appellate Authority in case of grievances against the order made by PCB's under the act, within a specified time and in the prescribed manner. xi) PCB's power to issue directions for: - the closure, prohibition or regulation of any industry, operation or process or; - the stoppage or regulation of supply of electricity, water or any other services to an industry in a prescribed manner. xii) Industry to comply with the directions of the PCB. xiii) Bar of jurisdiction to civil court in respect of any matter under purview of the Appellate Authority constituted under the act and no grant of injunction in respect of any action taken or proposed in pursuance of the Act. xiv) Bar on filing of any suit or legal proceeding against the Government or Board officials for taken in good faith in pursuance of the Act. xv) PCB's to maintain consent register containing particulars of consent issued and to provide access to industry at all reasonable hours.

Environment Legislation Provision Concerning Industry and Business The Environment i) Central Government's powers to take necessary (Protection) Act, 1986 measures for the purpose of protecting and including Rules 1986 improving the quality of the environment and (An act providing for the prevention, control and abatement of protection and environmental pollution. improvement of the ii) Central Government power's include: environment) - lay down standards for the quality of the environment, emissions or discharges of environmental pollutants from various sources. - restrict or prohibit industries, operations or processes in specified areas. - restrict or prohibit handling of hazardous substances in specified areas. - lay down procedures and safeguards for the prevention of accidents, which may cause environmental pollution. - enter and inspect any industrial establishments,

91 records, registers and documents to ensure effective implementation of the provisions of the Act. iii) Central Government has powers to issue directions for - the closure and prohibition or regulation of an industry, operations or processes or; - stopping or regulating the supply of electricity, water or any other service in the prescribed manner. iv) Industry to comply with such directions. v) Restriction on discharge or emission of pollutants in excess of the prescribed standards. vi) Handling of hazardous substances in accordance with the prescribed procedures and safeguards. vii) Industry to furnish information to specified agencies in case of discharges, emission of pollutants, in excess of the prescribed standards, already, occurred or likely to occur, resulting in environmental pollution, due to an accident or an unforeseen act or event. viii) Central Government has the power to recover, expenses incurred by it on remedial measures to prevent or mitigate environmental pollution, from the defaulting industry, as arrears of the land revenue or of public demand. ix) Central Government has the power to take samples of air, water, soil or other substances from any industrial plant for the purpose of analysis in the prescribed manner. x) Bar on filing of any suit or legal proceeding against Government or officials empowered by it for action taken in good faith, in pursuance of the

92 Act. xi) Bar of jurisdiction to civil court to entertain any suit or proceedings in respect of anything done, action taken or directions issued by the Central Government or any other authority empowered by it, in pursuance of the Act. xii) Industry, operations or processes requiring consent under the Water Act or Air Act or Authorization under the Hazardous Waste (Management and Handling) Rules, or both, to submit `Environmental Statement' every year before 30th for last financial year.

Environment Legislation Provision Concerning Industry and Business The Hazardous Wastes i) Occupier's responsibility to ensure proper (Management and Ha- handling and disposal of hazardous wastes, dling) Rules, 1989 either by themselves, or through the operator of hazardous waste management facility. ii) Restriction on handling of hazardous wastes without prior authorization from the PCB. iii) PCB has the power to suspend or cancel an authorization for handling hazardous wastes, after providing an opportunity to show cause and recording the reasons thereof. iv) Packaging, labelling and transportation of hazardous wastes to be done in the specified manner. v) PCB has power to refuse grant of authorization after providing reasonable opportunity of hearing to the occupier.

93 vi) State Government to identify sites for disposal of hazardous wastes within the states, and publish inventory containing relevant information. vii) Occupier generating hazardous wastes, or the operator handling the facility, to maintain records of such operations in the prescribed manner. viii) Occupier generating hazardous wastes, or the operator handling the facility, to submit annual returns in the prescribed forms. ix) Occupier or the operator handling facilities to report to the PCB in the prescribed form, in case of accident occurred at the hazardous waste handling site or during transportation. x) Specified procedures to be followed for import of hazardous wastes, to be used for processing or reuse as raw material. xi) Any person importing hazardous wastes to maintain records of the imports in the prescribed form for inspection purpose by regulatory agencies. xii) An occupier's appeal to the Appellate Authority in the prescribed manner in case of grievances against any order of suspension, cancellation or refusal of authorization by PCB.

Environment Legislation Provision Concerning Industry and Business Forest (Conservation) Act i) Restrictions on the dereservation of forests or use of forest 1980; including Rules as land for non-forest purposes, even if privately owned, amended up to till date) without the prior approval of the Central Government. 5.0 ENVIRONMENTAL APPRASIAL PROCEDURAL FRAME WORK FOR ESTABLISHING AND OPERATING AN INDUSTRIAL UNIT CATEGORY — I Project type Areas Ports, Harbours, Airports, Tourism Projects Doon valley, Costal regulation zone, between 200-500 meters of High tide line, Dhanu taluka, Maharashtra Mining projects

CATEGORY —H 1. Mining more than 5 hectares 2. Pit — head thermal power stations 3. Hydro power, major irrigation projects and/or their combination including flood control more than 50 crores 4. Ports and harbours (excluding minor ports more than 50 crores) 5. Exploration of minerals more than 500 hectares CATEGORY —IlT 1. Nuclear power and related projects such as heavy water plants, nuclear fuel complex, rare earths 2. Airports 3. Petroleum refineries including crude and product pipelines 4. Chemical fertilizers, (nitrogenous and phosphetic other than single super phosphate) 5. Petrochemical complex 6. Exploration for oil and gas and their production, transportation and storage 7. Synthetic rubber 8. Hydrocynic acid and its derivatives 9. a) Primary metallurgical industries (such as production of iron and steel, aluminium, copper, zinc, lead and ferro alloys) b) Electric arc furnaces (mini steel plants)

W, 10. Chlor-alkali industry 11. Viscose staple fiber and filament yarn 12. Storage batteries integrated with manufacture of oxides of lead and antimony alloy 13. Thermal power plants 14. Pulp, paper and newsprint 15. Cement CATEGORY —N 1. Pesticides (technical) 2. Bulk drugs and pharmaceutical 3. Asbestos and asbestos products 4. Integrated paint complex including resins and basic raw materials required in the manufacture of paints 5. Tourism projects 6. Highway projects 7. Tarred roads in the Himalayas and/or forest areas 8. Distilleries 9. Raw skins and hides 10. Dyes 11. Foundries (individual) 12. Electroplating

6.0 Environmental Management system (EMS) EMS certification is an opportunity that can enable companies acquire the label of environmentally sound enterprise and also accrue the benefits of improved economic performance. EMS should: a) identify and evaluate the environmental effects arising from the organisation's existing or proposed activities, products or services, to determine those of significance.

W. b) identify and evaluate the environmental effects arising from incidents, accidents and potential emergency situations. c) identify the relevant legislative and regulatory requirements. d) enable priorities to be identified and pertinent environmental objectives and targets to be set. e) facilitate planning, control, monitoring, corrective action, auditing and review activities to ensure both that the policy is complied with and that it remains relevant. f) be capable of evolution to suit changing circumstances. The standards are applicable to any organization which wishes to: a) assure itself of compliance with a stated environmental policy, and b) demonstrate such compliance to others. A policy should be indicated, developed by the top management not only conveying a commitment to meet all relevant regulatory and legislative requirements but also defining how it will be met. The responsibility of the management representative for implementing this standard should be coordination exercised in conjunction with line management in all functions, activities and processes. Advantages of EMS The advantages by acquiring EMS certification are: - Help in establishing company's image as environmentally responsible company; - Facilitates continuous improvement in environmental as well as financial performance; - Helps resource conservation and thereby higher profitability; - Less intervention from regulatory agencies; - Increased stakeholders confidence in the company; - Increased access to global markets; - Improved work environment. The Basel Convention The Basel Convention on the control of Transboundary Movement of Hazardous Wastes and their Disposal deals with hazardous wastes, their generation, storage movement, treatment, recovery and disposal.

97 Five main principles governs the Basel Convention: i) Minimization of waste (Prevention principle); ii) Disposal at the place of generation (Proximity and self-sufficiency principle); iii) Export of hazardous waste to countries capable of eliminating them in an environmentally sound manner (non-discriminatory adequacy principle) iv) Transboundry movement should be subjected to very stringent and regular control processes, and v) Increased international co-operation to assist developing countries to manage and treat the waste that they generate in an environmentally sound way. 7.0 List of projects requiring environmental clearance from the Central Government a) Nuclear power and related projects such as heavy water plants, nuclear fuel complex, rare earths. b) River valley projects including hydel power, major irrigation and combination including flood control. c) Ports, harbours, airports (except minor ports and harbours). d) Petroleum refineries including crude and product pipe lines. e) Chemical fertilizers ( nitrogenous and phosphatic) other than single superphosphate. Pesticides. g) Petrochemical complexs ( both olefinic and aromatic) and petro-chemical intermediates ' such as DMT, Caprolactam, LAB etc. and production of basic plastics such as LLDPE, HDPE, PP, PVC. h) Bulk drugs and pharmaceuticals. i) Exploration for oil and gas and their production, transportaion and storage. j) Synthetic rubber. k) Asbestos and asbestos products. 1) Hydrocyanic acid and its derivatives. m) Primary metallurgical industries ( such as production of iron and steel, aluminium, copper, zinc, lead and ferro-alloys). n) Chlor alkali industry. o) Integrated paint complex including manufacture of resins and basic raw materials required in manufacture of paints. p) Viscous staple fibre and filament yarn. q) Storage batteries integrated with manufacture of oxides of lead and lead antimony alloy. r) All tourism projects between 200 meters to 500 meters of high water line and its location with an elevation of more than 1000 meters with investment of more than Rs 5 crore. s) Thermal power plants. t) Mining projects( with leases more than 5 hectares). u) High way projects. v) Tarred roads in the Himalayas and or forest areas. w) Distilleries. x) Raw skins and hides. y) Pulp, paper and newsprint. z) Dyes. aa) Cement. bb) Foundries cc) Electroplating 8.0 Industry specific standards Environment ( Protection) Rules, 1986 SN Industry Parameter Standards 1 Small Pulp and Paper Industry

Discharges into Ph 5.5-9.0 inland surface Suspended solids 100 water BOD 30 Disposal on land Ph 5.5-9.0 Suspended solids 100 BOD 100 Sodium absorption ratio 26 2 Nitric Acid Emission of Oxides of 3 Kgs of oxides of nitrogen (emission oxide Nitrogen per tonne of weak acid of nitrogen) before cone.) produced. 3 Sulphuric Acid Sulpher dioxide emissions 4 kgs per tonne of (emission of concentrated ( one hundred sulphur dioxide percent) acid produced. and acid mist) Acid mist 50 milligramme per normal cubic meter.

4 Large pulp and Emissions Concentraion in mg/m3 Paer (normal) Particulate matter 250 H2S 10 5 Small Boilers Capacity of Particulate matter Mg/m3 Boiler -Less than 2 1600 mg/Nm3 ton/hr -2 to 5 ton/hr 1200 mg/Nm3 -More than 15 150 mg/Nm3 ton/hr

100 CHEPTER 9 Environmental Management at Ballarpur Industries Ltd, unit - Shree Gopal

ABSTRACT Pulp and paper industry is one of the major polluted industry in the world. Rigid environmental compulsions in the industry have forced to look for drastic measures to recycle natural resources by adopting eco-friendly practices. Environmental protection is no longer a new issue now. Right from Government up to the common public environmental degradation has become a issue of concern. Of late, Central Pollution Control Board has issued another directive in the form of Corporate Responsibility on Environmental Protection (CREP). To keep pace with the changed concept, Ballarpur Industries Ltd, unit Shree Gopal, Yamuna Nagar, one of the major Paper mill in the North India region, has already implemented or in the process of implementation under environmental management system. AOX, considered to be one of the major toxic chlorinated compounds, is very less i.e. 0.7kg/MT as compared to the present stipulated norms in outgoing treated effluent. The treated waste water being discharged is extensively used in the in-house gardening. Local formers are also educated to use the treated effluent for irrigation purpose. The treated effluent quantity has decreased considerably over the last 5-6 years. We have taken lot of measures to bring down fresh water consumption from 223 to 120 m3/t of paper. ESP in recovery boiler and Lime reburning process are in the operation. The above contributes to improvement of Mill's environmental performances. INTRODUCTION Environmental conservation or preservation is a major task before all world. Though, we have done many things for the preservation of the environment as well as for improvement of environmental performance and still many things are yet to be done (1). Environmental management system adopted in industrial units covers all spots of pollutant, waste materials, ecology, recycling of rejected products, noise, odors and other visual amenity (2). It also embraces energy, land conservation of natural resources and

101 heritage. Naturally any environment friendly industrial plant is bound to respond to these problems positively. However, in all cases prevention of pollution demand the maximum attention (1) . The Indian paper industry uses a lot of fresh water for the production of paper. As against the international benchmark of about 50m3/t of paper, an average Indian mill uses about 200m3/t of paper. Recently, some units have had to suspend production due to water shortage. Water is mainly used for washing of pulp. The industry endeavors at adopting technologies that bring down the consumption of fresh water to less that 100m3/t of paper by 2006, which implies not only technological intervention but also daily regulation of water consumption in operations. As per CREP requirements by 2007, the large pulp and paper mills, installed before 1992 have to reduce their effluent discharge to less than 120 m3/t of paper (3). This stipulation coupled with the natural shortfall of fresh water has guided the industry explore efficient washing systems and systems closure by reusing various streams to reduce the total water consumption (4).

The recent change in the Indian paper industry has their genesis on the stringent environmental regulations stipulated by the chapter on corporate responsibility for environment protection. The provisions of the chapter (which has been adopted by the industry for implementation) have acted as growth drives for the Indian paper industry. The large paper mills, which account for a little more than one third of the total production, have adopted significant technology up-gradation programs that aim to reduce AOX emissions through chlorine dioxide bleaching. This move of the large-scale sector has been driven by the AOX emission limit of 1.5 kg/t of paper, which must technically be achieved in the year 2005. Since this emission limit is to be further lowered to 1.Okg/t of paper. It will impact the industry to adopt the state of the art ECF bleaching and oxygen delignification technologies. In this paper, the activities completed for the protection of environment are discussed (3). Solids waste is often called third pollution after air and water pollution. The principal sources of solid wastes are domestic, commercial, industrial and agricultural activities. Industrial activities alone generate about 85% of the total solids wastes (4). The disposal problem is getting many fold day by day, mainly due to stringent laws formulated by the

102 legal authorities. It is encouraging that, today some of the industrial waste are utilized and recycled while others can be used as energy sources. However, it is seen that the inorganic part is creating disposal problem to a larger extent. Lime mud, which is an inorganic waste, is being generated by all large paper plants. Actions have already been initiated to install a Lime mud re-burning plant, so that lime mud disposal problem is reduced to minimum along with a minimum utilization of natural resources. It is also proposed that once the plant is commissioned, provisions will be there for burning non- combustible odour creating gases in the Kiln. BILT, UNIT SHREE GOAPL - A BRIEF INTRODUCTION The unit is an ISO 9001:2000 certified integrated pulp & paper mill, having 6 paper machines & manufactures 85000 MT/annum of various grades of writing & printing, industrial grades of paper & coated boards like Royal Executive, Sunshine super printing, Electrical grade, Ivory board & Black center board (BCB). The unit also has blade coater (state of art technology), which produces approx 15000 MT/annum of coated boards with captive power generation plant - two turbines (One — 18 MWH & other 6.25 MWH). It has state-of-art pulp mill, DCS controlled, having CD-EOP-DI-D2 bleaching sequence. The chemical recovery plant consists of evaporators, two recovery boilers (ABL & JMW) and causticizing plant. The plant has recovery efficiency of 96.3%

The unit has also full fledged state of the art effluent treatment plant based upon activated sludge process. It consists of primary, secondary and tertiary treatment along with aeration tank, thickener & sludge dewatering machine (Andritz filter press). It is the only paper mill in India having tertiary treatment in ET plant.

ENVIRONMENTAL MEASURES AT PLANT

Water conservation Water has become a precious commodity. A scientific arrangement of water usage is warranted not only to save the resource but also to reduce the wastage of input chemicals. Improvements in pulping and paper technology have been focusing on ways of reducing the specific water consumption. With dwindling water resource availability, the mill is

103 now taking regular measures to cope with situation since water is the major raw material for (6). During the last six years, there is significant reduction in the water consumption. In 2000-01, the water consumption was 213 m3/t of paper, which has reduced to 120 m3/t of paper in 2005-06. This is the result of various steps taken over the period to reduce fresh water consumption. Action taken to reduce water conservation The major steps taken are given in table no. 1. and modified flow chart of recycling of machine backwater is given fig.]. The water consumption & effluent discharge patterns over the last 6 years are given in Fig 2 & 3 respectively.

Table 1: Actions for water conservation Activity Water Saving S.No. m'/hrs 1. Use of disc save-all effluent on wire showers & wash roll edges at all m/cs 75 2. Reuse of water on all machines vacuum pump by passing through cooling tower 115 3 Reuse of pope reel and compressor water to water reservoir 30 4 Use of machine back water in cy% controller and pulp dilution at pulp mill 28 5 Stopping of over flow of jet condenser pit and reduction of fresh water at 35 chemical house by putting level controller & pump 6 Use of special type gland packing in 20 pumps/refiners 10

7 Replacement if existing MC pump with high efficient pump 15

8 Reduction in use of gland cooling water by providing Macstar packing (36 14 pumps) 9 Modification of feed pump to supply M/c 1,2&4 back water to brown stock 15 washer 10. Thickener shower of m/cl &2 replaced with new showers 8

104

Fresh Water Line From Pump House

a Clear water ter 2 from fro disc save e Cutting aid HP I H.P Pump ,adaaaaaaa

Air Compressor Squirt Suction Nozzles Couch/press I Dandy : WirP Chc~wPrc Racaninir ~—

I Wire H.P

Presses : Deckle • Felt • Conditionina H.P Hose Couch Pit Hose Pipe 1S` Press H.P I I Shower

Thickener

Excess B/w I- Back Water Channel Drain

Cooling -*; Disc Filter ■ ■ ■ .. ■ ■ ■ ■ . ■ ■ . ■ b + i s Indicate the »wdification

Vacuum pumps ■ To Pulp Mill For sealing Pulp Dilution

Figure 1 : Modified flow chart for recycling of machine back water at m/c#4.

105 Water consumption m3/t of paper Effluent discharge m3It of paper ME 250 250 C 0 184 a, 203 E 200 L 200 o ? 0 170 162 158 o 150 136 m E 150 `' 125 100 11 r N M et Lo CD O O O O 100 O O r N M et La co O N Cl)o t t O O O O O O O —O O O O O O O O O O O O T_ N M d0 u7 N N N N N O O O O O O N O O O O O O Year N N N N N N Year Figure 2: Water consumption Figure 3: Effluent discharge

Waste water management Several treatment and control technologies have been developed to reduce wastewater or pollutant discharge to natural watercourse. The two major technology approaches are: • Production process controls aimed at reducing wastewater volume and pollutant load discharge from the mill. • Wastewater treatment technology or end- of -pipe treatment systems aimed at reducing discharge of pollutants contained in the water (7). Both these approaches have been adopted by us, however, the process control system has been widely focused so that, the pollutants generated can be reduced at the point of generation itself We have an effluent treatment plant having a capacity of 2200 m3/hr. Introduction of tertiary clarifier in the treatment facility has significant effect in reducing the suspended solid, BOD and COD. A typical analysis of treated effluent along with norms laid down by Haryana State Pollution Control Board (HSPCB) is given in Table no 2. COD, BOD, suspended solids & AOX are much below than the specification laid down by HSPCB. It may be noted that the colour of the treated effluent is very much on the lower side as compared to the Indian .pulp & paper mills effluent. The treated effluent is utilized in the processes and irrigation. The excess effluent is discharged to canal.

1: Action taken to reduce pollutant load

➢ Low Kappa No of the unbleached pulp - (18-20) ➢ Partial substitution with C102 in chlorination stage — (10%) > Oxidative extraction reinforced with hydrogen peroxide at bleach pant. > Increased the oxygenation in aeration tank/ biological process at ETP. > Black liquor spillage control. at pulp mill and soda recovery. - At pulp mill two pit of 30 m3 each along with the tank of 250 rn' capacity in digester house installed and black liquor is recycles through stock chest (Fig 4) . - Inducting a pit of 50m3 capacity at soda recovery and at recycling back into the process along with the three pit from ABL and JMW recovery boiler (Fig 5). > Recycling of Eop backwater for the dilution of CD washer pulp.

➢ Introduction of lime treatment in the combined effluent of pulp mill & recovery has resulted in 30% reduction in colour load and COD. The characteristics of the treated effluent (avg. value) over the period of six year in regards to AOX, COD/BOD, suspended solids, colour are given in figs 6, 7, 8 & 9 respectively

107 Further Receive effluent from soda recovery processing /boiler/evaporators at soda B/I from B/I from recovery B/I from screen junk & knots knots pumps gland leakages in Feeding Handling Digester house Point Place

Check effluent colour I I Thin B/L Tank & Conductivity B/I pit (near silo) I I B/I pit (near silo) B/I pit (near silo) No Is colour 0 Stock chest Cond.<1000 RCC PIT

Yes

Blow tank Effluent goes to ETP

Figure 4: Spillage collection system Figure 5: Spillage collection system

pulping & washing Chemical house evaporators

Table 2: Treated effluent characteristics

Particulars Unit Influent Treated water HSPCB norms effluent effluent PH NA 7-8 7.2-7.8 7.0-8.5 BOD PPM 280-350 7-11 30 max.

COD PPM 700-900 80-95 350 max. Suspended PPM 700-900 15-25 50 max. solid AOX kg/T Paper 1.2-1.6 0.63 <1.5

1: AOX of treated effluent Kg/ton of paper 2.5 2.1

1.4 1.1

0.7 0.7 0.5

Cpl 4 94 4 9 °o 0 0 0 0 N N N N N N Year

CODISOD mg/l

120 105 I 98 100 85 1 80 ❑coo E 60 O BOD 40

20 LI] 0 9 N 9 9 9 9 o o 0 0 0 0 o 0 0 0 0 0 N- N N N N N Year

Figure 6: AOX kg/ton of paper Figure 7. COD/BOD

109

Suspended Soild of treated Treated effluent Colour Pt/Co

effluent unit 400

40 34 33 350 30 0 300 E 22 22 20 1 a 250 20

10 =i 1=ill CO co o o 0 0 0 o 0 0 0 0 O M U) O MN d LA N d O 0 0 0 0 0 °o o 0 0 0 o N N N N N N N N 0 N N Year Year

Figure 8: Suspended solid Figure 9: Colour of treated effluent Utilization of treated effluent The treated effluent is used in the process at various locations. The major uses are > Raw Material Wetting: 80m3/day > Coal Ash Quenching: 1000m3/day

➢ Ejector Cooler at soda recovery evaporators: 400 m3/day ➢ Jet condenser of the evaporators: 1200 m3/day. ➢ Broke chest pump for gland cooling at 8 pumps: 100m3/day ➢ Chemical house pumps for gland cooling at 6 pumps: 80m3/day ➢ Gland cooling of all refiners: 200m3/day The excess treated effluent is utilized for gardening in mills & colony (Fig 10). The approximate quantity is 1800 m3/day. It is also used for irrigation, as a demonstration to the local formers, to promote the use of treated effluent for paddy crops cultivation. Lime mud management In recovery plant, approx 100 MT of lime sludge (on dry basis) was generated every day. A rotary lime reburning kiln of capacity 60 MT/day of lime has been commissioned in Jan'05 and running successfully since then, though as per CREP lime kiln should be installed by Mar'07. The purity of lime in the reburnt lime is in the range of 78-80% with a make up of 10 % limestone. Lime kiln .operation has improved over the period of time by employing the following measures. This has also resulted increased in recovery efficiency (Fig. 11). The lime mud generation and available CaO are given in Fig 12 & 13 respectively Action taken for process modification

➢ Stationary slaker installed in place of rotary slaker to increase retention time in existing rotary slaker

➢ Green liquor temperature increased by modifying the steam coil in causticizing plant.

➢ Temperature of hot water increased by using LP steam for lime mud washer. > Control valve installed in wash water line to control Irregular & less wash addition at dreg washer.

➢ Sludge temperature raised by installation of steam coil in the sludge tank, sludge supply line and increasing hot wash water temp.

➢ Baffles introduced at the main inlet, 1st and 2°d field for uniform distribution of the Gas across the electrodes in ESP. Recovery efficiency, % 98

96.3 96 rn 95.2

94 94 a 93

92 92

90 4 4 4 4 4 4 N N H N N Year

Figure 11: Recovery efficiency

112

Lime mud generation, Avg. MT/DAY 120 100 80 60 40

20 11 0 o o o o 0 0 O N Cl) et U) o r CO O O 0 O N N N N N N Year

Available CaO (%) in reburnt lime 82

80 0 C.j78 d 76

> 74

72

70 UA 10 CD Un U) U) u) 10 ce ce CD CD co co co o 0000002 0 °>, °c °— a) O. ya °> n° L L

Month

Figure 12: Generation of Lime Mud Figure 13: Available Cao%

Air pollution control measures

We have two recovery . boilers namely ABL & JMW. Both are equipped with Electrostatic precipitator (ESP), Recently in June, 05, we have commissioned new ESP

with the target emission level < 100 mg/Nm3. Current emission level is 80-130 mg/Nm3 and running quite successfully. ESP for JMW recovery boiler has also been upgraded and running satisfactorily. Suspended Particulate Matter (SPM) values for the last one- year are given in the Fig 14.

113 SPM of JMW & ABL recovery boiler 180 160 E 140 z 1120 uIIN• 100 80 ii_IIU 60 iiII.I' 1Ii ac? a9I' a9 09 "1N U) -C i -a L) .0 Lo N Year 2005-06

Figure 14: SPM of JMW and ABL

CREP-Status as on August 06

Particular Commitment Status

AOX <1.5 kg/ton of paper by 31.3.05 Present value 0.63 to 0.70 kg/ton of paper Discharge <1.0kg/ton of paper by 31.3.08 Lime Kiln Installation before 31.3.07 Lime kiln in operation from 15 Jan05 onwards Production : 57-60 TPD Purity :78-80% Effluent <140 m3/ton of paper by 31.3.05 Present value-1 10 m3/ton of paper volume <120 m3/ton of paper by 31.3.07 NCG control -Installation before 31.3.07 Blow heat recovery Upgradation will be completed Incineration in lime kiln by March 07. Study for NCG handling will be done by June 07 (ENMAS-ANDRITZ) Irrigation Utilization of treated effluent for - Existing park & garden in the mills & colony are irrigation being irrigated with the treated effluent. - Paddy crop developed with treated effluent new ETP & A-1 bungalow. - One acre land is being developed with treated effluent for sugar cane crop in the mill premises.

114 CONCLUSION The investment made in environment protection may not pay tangibly but benefits derived out of such investment can be reused in terms of fulfillment of social obligation, which is more important for survival of any industry. In the context CREP have a lasting positive impact on protection of environment.

FUTURE ACTIONS > To install new disc filter for the reduction of water consumption < 120 m3/t of paper

➢ To install Producer gas plant as a fuel for lime kiln in place of depleting furnace oil as nature resource.

➢ Upgradation of blow heat recovery system for incineration of Non condensable gases (NCG).

➢ Incineration ofNCG (Mercaptans) emitting from Blow Heat Recovery (BHR) areas of pulping and soda recovery evaporators.

115 CHEPTER — 10 TOWARDS ZERO-EFFLUENT PULP AND PAPER PRODUCTION: The Pivotal Role of Totally Chlorine Free Bleaching

EXECUTIVE SUMMARY

The world pulp and paper industry continues to expand production and increasingly, plants are being built in newly industrialised countries. The dominant process is the kraft or sulphate process. Historically, substantial pollution problems have been associated with pulp manufacturing operations. Following the recognition of large scale environmental contamination by organochlorines due to their formation in bleach plants, the industry implemented a number of process internal changes and continued to develop process external treatment processes. The bleach plant of kraft mills generates a substantial proportion of the total process effluents.

The introduction of extended delignification and oxygen delignification can substantially reduce the quantities of lignin entering the bleach plant. Residues from oxygen delignification can be cycled to the recovery process. Overall, this reduces the demand for bleaching agents and hence reduces the generation of organochlorines. Together with substitution of elemental chlorine (Cl2) with chlorine dioxide, these systems have substantially reduced levels of AOX being discharged from bleach kraft mills. Organochlorines, however, have not been eliminated from discharges, merely reduced. Swedish research has shown detectable levels of toxicologically chlorinated dioxins and dibenzofurans in the effluents from mills that use chlorine dioxide; so-called (ECF) mills.

This stems from the fact that ECF processes are not free of elemental chlorine. Commercial chlorine dioxide generators in many cases co-generate molecular chlorine. Moreover, chemical reactions and pH dependent chemical equilibria in pulp bleaching

116 reactions involving chlorine dioxide liberate molecular chlorine. This molecular chlorine then reacts with chemicals released from the wood.

Organochlorine production in ECF processes is within a broad range of 0.1-10.0 kg per tonne of air dried pulp produced. The global average is unknown. The improvements engendered by process internal measures are still under investigation. Available results indicate that the greater the degree of chlorine dioxide substitution and early delignification, the better the effluent quality achieved. Many mills, however, have not adopted these stages and therefore discharges of organochlorines are relatively high.

The elimination of organochlorine discharges can be achieved by the use of TCF (Totally Chlorine Free) bleaching where agents such as hydrogen peroxide and ozone are used. A necessary prerequisite of TCF bleaching is a pulp with low residual lignin (kappa number) produced through extended cooking and oxygen delignification. Conversion of existing mills favours this technology over chlorine dioxide based processes in economic terms. In addition the cost of new TCF plant is cheaper than ECF.

In terms of effluent toxicity, TCF systems produce a less toxic effluent than elemental chlorine bleached processes when realistic conditions using actual mill effluents are employed in the experiments as opposed to samples synthesised in the laboratory. Today it is estimated that some 15-20 true TCF mills exist. Recently, however, effects have been identified in fish populations exposed to effluents from pulp mills producing both bleached and unbleached pulp. The chemicals responsible are not removed by advanced secondary treatment and are suspected to be plant sterols or their derivatives which have a strong endocrine disruptive action.

The identification of environmental effects due to both bleached and unbleached pulping activities has led to the concept of the totally effluent free mill. A key impediment to fully closing mill circuits is the difficulty of closure of the bleach lines. Although problems exist with closing both ECF and TCF lines, those involved in closing ECF lines appear to be the most difficult and costly to resolve.

117 The presence of high levels of chlorides in an acid bleach medium has been associated with severe corrosion problems, and hence the possibility of explosion in recovery boiler systems. Moreover, the presence of organochlorines in both filtrates of ECF bleach liquors and in sludges from treatment plants means that they cannot be incinerated without the emission of products of incomplete combustion including the dioxins and furans (PCDDs and PCDFs). Both closed circuit mills currently operating in Canada are CTMP (chemi-thermomechanical pulp) mills which do not use chlorine chemicals in the bleach cycle.

Accordingly, in order to reach likely regulatory standards in the future, closure of mill circuits will be necessary. This is likely to be more easily achievable with TCF technology since there will be a lower requirement for chloride removal from the process liquors. In addition there is much greater potential to deal with these streams without the use of incineration technology. In order to avoid transferring environmental impacts from one medium to another, incineration of ECF derived sludges and other solids will need to be eliminated. Hence, movement of the industry generally into TCF processes rather than ECF systems promises more rapid achievement of the zero discharge goal.

In order to promote sound environmental practice and move towards zero effluent mills, environmental regulators need to promote the need for process changes. Extended cooking and oxygen delignification of pulps is required to reduce the quantities of lignin entering the bleach plant. The bleach plant should be based upon totally chlorine free technologies to reduce effluent toxicity as much as possible and to facilitate water and process chemical recycling without need for incineration of sludge contaminated with organochlorine compounds. Under these conditions, the mill circuits can effectively be closed and operated totally effluent free (TEF).

INTRODUCTION

World wide consumption of paper products now exceeds 268 million tons per year (PPI 1995). This is up from 238 million tons in 1990 (PPI 1991) which, in turn, increased from 170 million tons in the late 1970s (Smook 1989). Apparent per capita consumption is greatest in the United States at 332.6 kg of pulp products, while, by contrast the 1990

118 figure for Malta was 71.2 kg and that for India was estimated at 2.7kg (PPI 1991). The pulp and paper industry is expected generally to grow significantly in the newly industrialised countries of Africa and Latin America. The highest rates of growth, however, are expected in SE Asia, a premise borne out by the latest world industry figures (PPI 1995). Elsewhere continued growth is also forecast, although at a lower rate than in the past. World consumption is projected to rise to over 310 million tonnes in the year 2000 (Myreen 1994). The changes within the industry are expected to have a significant impact on the chemical industry as well. Some 16.5 million tons of chemicals are used annually in the US and Canadian industries alone. Approximately US$50 worth of chemicals are used in the production of every ton of bleached softwood pulp, US$20 per ton of newsprint and US$80 per ton of reprographic papers (Burt 1987).

The different grades are likely to show differential growth rates but no specific product group is thought likely to disappear from the market. The average composition of products, however, will change. In general, the greater the requirement for fibre purity, the lower the yield of fibre and the greater the cost. Although recycled fibre is predicted to become - a major fibre resource with some estimates that it may ultimately comprise 50% of the total fibre furnish, this is likely to be highly influenced by considerations of energy consumption. The production of mechanical and recycled pulps are energy intensive processes. In addition, (Bystrom & Lonnstedt 1995), the utilisation rates for waste paper in Europe are already regarded as high, leaving limited scope for the use of waste paper in production. These current general trends are shown in Figure 1. The pulp market overall will be dominated by bleached kraft (sulphate) hardwood and softwood pulps.

Historically, pulp and paper production has long been recognised as a significant point source of pollution. Early control initiatives in the UK, for example, concentrated upon reducing the loading of suspended solids and biological oxygen demand to the recipient (Waldmeyer. 1957). BOD control is still problematic in areas where discharges are made to restricted watercourses or enclosed coastal areas. A recent study of the Sone River in India (Srivastava et al. 1988) has shown that the river effectively required 216 km to revert to its original condition after receiving the effluent from a mill of installed capacity

119 of 85kt per year. Estimated BOD-7 discharges direct to the Gulf of Bothnia, Gulf of Finland, Baltic Sea and Kattegat totalled some 180kt per year in the late 1980s (CGB 1987).

Technologies used or under development at this time included percolating filters, activated sludge processes, anaerobic treatment and high pressure oxidation. These were all broadly end-of-pipe methodologies whose counterparts may be found at many modern mills.

Aerated lagoon systems have to a large extent become the industry standard for wastewater treatment. Process controls, then as now, included fibre recovery systems to reduce loadings of particulates to receiving waters. As in the UK, (Edde 1994) early pollution abatement initiatives in the- USA were based largely, upon a system of recipient water quality objectives coupled with definition of the notional "assimilative capacity" of the recipient. Subsequently, multi-tiered frameworks of environmental regulation have been evolved in a number of countries (see: Gifford & McFarlane 1991; Sprague 1991; Edde 1994).

Despite this preoccupation with biological oxygen demand and total suspended solids, however, some early work (eg Ebeling 1931) had remarked on the toxicity of pulp effluents and noted the resinous taste that they imparted to fish flesh. Beginning in the late 1960s there was an increasing awareness of the toxic properties of pulp and paper effluents which had previously been obscured by the excessive BOD demand placed on the receiving waters. The emphasis gradually shifted from unbleached kraft mill wastes to bleached mill wastes and a number of attempts were made to isolate the toxic components. This early work has been comprehensively reviewed by Walden (1976).

As noted by Minor (1982), the pulp and paper industry- has had three very difficult problems to control as follows: the development of suitable methods for sulphite waste liquor recovery, elimination of malodorous and toxic sulphur compound emissions from the kraft pulping process and the elimination of toxic compounds, BOD, COD and colour from bleach plant effluents. The solution of the bleach plant problems has proven to be

120 the most difficult. Arguably, this aspect of pulp production is the single most important determinant of environmental impact of such operations and the single greatest impediment to reducing and eliminating the environmental impact of pulp production facilities.

Accordingly, this document traces the evolution of bleaching techniques and the problems associated with pulp effluents in receiving waters. It discusses the critical need to modify bleaching processes in order to control more fully process effluents. In particular it examines the use of chlorine dioxide as a substitute for chlorine as a pulp bleach. It reaches the conclusion that if the zero effluent mill is to become a realistic prospect and the industry standard, then all forms of chlorine based bleaching agents need to be substituted for.

PULP PRODUCTION PROCESSES

Although the history of papermaking dates back to the first century BC (Minor 1982) the modern process dates back to the opening of the Frogmore Mill in England in 1798 (Myreen 1994) producing paper from rags. The extreme short-supply of rags was alleviated in the late 1870s when it became technically feasible to produce pulp from wood. This was a turning point in the development of the industry which subsequently evolved from an artisanal activity to a fully, mechanised industry (Kerski 1995). Subsequently, paper mills came to be located by rivers with afforested catchments, facilitating transport of the mill wood furnish and the use of the rivers for power and process water.

The production of pulp is the single most important technique for the chemical conversion of wood and accounts for more than one third of the total processed mass annually: 460 million cubic metres out of a total 2600 million cubic metres harvested which includes the 1500 million cubic metres used for fuel wood (Fengel & Wegener 1989). Another perspective is provided by Kerski (1995) who estimates that the annual timber consumption equates to the production of a land area of over 20,000 square kilometres, or around half the area of Switzerland. Pulp and paper production accounts

121 for one per cent of the world's total economic output. The 1992, 1993 and 1994 production figures of the 10 largest pulp producing countries, accounting for around 85% of the total world pulp production are shown in Table 1 (PPI 1992; 1993; 1994). The rapid and steady increase in demand for pulp products is coupled with an increasing shortage of wood supplies. Hence, short-rotation intensive culture plantations are now being actively researched as a source of mill furnish (Sierra-Alvarez & Tjeerdsma 1995).

Table 1: Pulp production figures for top producers in 1994 as compared to previous years. Data from PPI (1993; 1994; 1995).

Wood is chemically very highly complex. The basic structural element of the cell walls is cellulose. Lignin and hemicellulose are also distributed throughout the cell walls, although this distribution is poorly understood (Minor 1982; Fengel and Wegener 1989). The relative proportions vary, but in the cells of Scots pine, the relative proportions are 28.0 weight % lignin, 28.7 wt% hemicellulose and 40.3 weight % cellulose. In addition wood contains 3-10% of "extractives". This fraction includes fats and esters, terpenes and resin acids, phenolic materials and tannins. Trace quantities of inorganic materials are also present together with heavy metals. The lignin component binds the cellulose fibres together and in order to produce paper the fibres must be separated from each other. This may be achieved mechanically or by chemical dissolution of the lignin.

122 Pulping is the means whereby the wood is reduced to a fibrous mass for onward processing into paper and board products. After harvesting, the wood is debarked mechanically and converted to chips of specified size. The chips are screened and then pulped. An extensive overview of pulping procedures and treatments is given by Fengel & Wegener (1989) and Minor (1982) and the reader is referred to these documents for more detailed information. There are a variety of methods for producing pulps mechanically and several chemical pulping methods are in use. Chlor-alkali products are widely used in the refining and bleaching processes involved in the manufacture of chemical pulps. The pulping method of choice will depend upon a number of factors including the grade of paper being manufactured. Different paper qualities utilise different types of fibres. In a copying paper, for example, hardwood fibre is used as the bulk with softwood fibre added to impart mechanical strength. Newsprint is manufactured predominantly of mechanical or recycled fibres with a small component of soft wood fibre to impart strengthening properties.

Table 2: World regional production of pulp by types for 1990 & 1994. Apparent decline in total figures for Europe is due to closure of plants in the former Eastern Bloc. Data from PPI (1991; 1995). C= Chemical pulp, M= Mechanical pulp, 0= Other pulp types.

123 Table 3. World production of pulp according to pulping method in 1979. Data from Fengel & Wegener (1979)

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124 1 6 11 P6 1247 1117 I!I I 11 II CS 111140 1IS 6 11194 16 TotJ 915

Table 4: Pulp production figures for top producers in 1994 by category of pulp. Data from PPI (1994). B= bleached, U= unbleached, S= semichemical, M= mechanical. Figures for China [*] derived from limited dataset. Disparity between data in Table 1 due to omission of other pulp types and differences in data sources.

All pulping processes are designed to separate the wood fibres present in the wood. Mechanical processes achieve this by grinding or tearing the fibres apart. Chemical processes dissolve the lignin present between the cells allowing the fibres to separate with little or no mechanical action. Techniques available vary between these. two extremes. The industry balance of pulping methods is shown in Tables 2 & 3 taken from PPI 1991;1995 & Fengel and Wegener (1989). Table 4 shows the balance of pulping methods used by top producers. The major pulp production methods can be categorised as follows:

1) Groundwood nulnin

These processes essentially grind the raw wood to produce a pulp yield of between 90 and 98% in modern systems. Modifications to the process include the use of steam as a lignin softening agent and carrying out the process. under positive pressure. Uses of this pulp are generally restricted to applications such as newsprint, toilet tissues and since it tends to yellow on age due to the content of residual lignin.

2) Refiner mechanical pulpin

This process differs from groundwood pulping principally in the use of chips, wafers and sawmill wastes as feedstock. The dominant process is thermo-mechanical pulp where the wood chips are preheated and steamed before being fed to one of the three standard disc- refiner systems. The resulting pulps are somewhat less bright for a given wood species than groundwood pulps.

125 3) Semi-chemical pulping

Semi-chemical pulping processes are characterised by a chemical pretreatment stage followed by a mechanical refining step. The process uses predominantly hardwoods and can accommodate wood of relatively inferior quality and wood obtained from mixed stands. The best known of these processes is the neutral sulphite semichemical process and involves impregnation of the chips with sodium sulphite liquor, followed by cooking at 160-190 C and a subsequent disc refining stage. The pulps produced typically have 10- 15% residual lignin, much higher than the full chemical pulps. The pulps have high rigidity and stiffness and are used in corrugated boards as well as printing papers, greaseproof papers and bond papers. There is no, clear demarcation between the semi- chemical processes and the high yield chemical processes which are generally modifications of the normal kraft and sulphite pulping methods.

4) Chemical pulps a) Alkaline chemical pulpitzg

The two major alkaline processes for producing chemical pulps are the alkaline sulphate or "kraft" process and the soda process. In both these processes wood chips are cooked with sodium hydroxide in order to dissolve the lignin which binds the fibres together. Sodium sulphide is an additional component of the pulping chemical mix in the krafl process. Both processes are named according to the regeneration chemicals used to compensate for sodium hydroxide: sodium sulphate and sodium carbonate. The kraft process is not only the dominant chemical pulping process but the most important overall in terms of the various production methods. The soda process is important largely in the production of non-wood pulps. Various modifications to the kraft and soda processes have been devised in order to attempt to overcome low pulp yields and environmental problems. These generally involve the addition of chemicals to the digest liquor. The most important of these is anthraquinone (AQ). The benefits of AQ pulping include increased delignification rates together with reduced alkali charges and improved pulp properties.

126 An integral and economically vital part of alkaline pulping mill operations is the regeneration of the cooking liquors (Fengel & Wegener 1989; Minor 1982). The recovery cycle is well defined for the kraft process and is designed to recover pulping chemicals, reduce water pollution by combusting organic matter in the spent liquor, generate process heat and recover by-products of value. The main steps in the process are the evaporation of the black liquor drained from the digester after wood chip digestion, combustion of the concentrated liquor to produce a mineral "smelt", causticisation of the smelt and regeneration of the lime used in the process. The energy content of the black liquor is high. Gullichsen (1991) notes that half of the wood is dissolved during the manufacture of chemical pulp, and this, when combusted in the recovery boiler, provides heat for the plant systems.

The heart of the process is the recovery furnace. The black liquor is evaporated to a solids content of between 60% and 75% using a 5-6 stage system and this is followed by direct contact evaporation in which flue gas from the recovery boiler is brought directly into contact with the liquor. Tall oil soaps are recovered during the evaporation stages. Oxidation of the liquor prior to evaporation can be carried out to reduce the emission of malodorous compounds. When the black liquor is concentrated, sodium sulphate and other chemicals are added to compensate for those lost in the pulping process.

In the recovery boiler, the organic content is combusted to produce heat. Carbon dioxide reacts with sodium hydroxide to produce sodium carbonate. The added sodium sulphate is reduced to sodium sulphide and hence the solid smelt produced by the boiler contains largely sodium carbonate and sodium sulphide. This is dissolved in a tank to produce the green liquor which is subsequently filtered and treated with calcium hydroxide (slaked lime) to convert the sodium carbonate to sodium hydroxide. The resulting white liquor is then returned to the digestion process. The lime is regenerated by heating and mixing with water removed from the green liquor. This process is, therefore, theoretically closed in relation to water use but not with respect to atmospheric emissions, spills and condensate generation.

127 The pulps produced by the kraft process are characterised by good strength properties. They are, therefore, the preferred grades in strong paper grades such as the liner in corrugating boards or bag and wrapping papers. Hardwood kraft pulps are used in many printing papers for bulking purposes, in mixture with softwood pulps. The residual lignin present in the pulp is expressed in terms of the "kappa number" which is determined by the oxidation of.lignin by potassium permanganate under acidic conditions. The lower the kappa number of a pulp, the lower the level of residual lignin. b) Sulphite chemical pulping

The basic processes for the manufacture of sulphite chemical pulps are outlined by Fengel and Wegener (1989) and Minor (1982). These are the acidic sulphite process, bisulphite process, multi-stage sulphite process, neutral sulphite process and alkaline sulphite process. All are described in terms of the composition of the cooking liquor which in turn defines the process pH and the choice of basic chemicals used. The gas sulphur dioxide is used to generate the sulphite chemicals used in digestion. Pulping conditions vary widely according to the mill furnish and the different processes produce pulps of differing chemical composition and papermaking application.

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This pulping method has been receiving increased attention in recent years. Solvent pulping offers a number of potential advantages over conventional pulping techniques such as relatively low chemical and energy consumption coupled with low capital costs and low environmental impact. Aqueous organic solvents such as methanol and ethanol are used for delignification to produce a bleachable pulp which can be bleached with non- chlorine chemicals. Pilot scale tests have given high pulp yields with strength properties similar to sulphite and kraft pulps (see: Sierra-Alvarez & Tjeerdsma 1995).

4.0 WATER USE

Water is an important consumable in the production of pulp and paper. With time, however, there has been a progressive reduction in the use of water at mills (Edde 1994) considered in relation to all types of mill. Whereas in 1959 around 240 cubic metres of water were used in the production of 1 tonne of air dried pulp, by 1988 average water usage had been reduced to 72 cubic metres per air dried tonne. The most recent technology, installed in South Africa, has a water demand of 16 m3 per air dried tonne. Table 5 shows the main sources of aqueous effluent produced in a bleached kraft mill.

129 TABLE 5 Effluent arisings from various mill processes with various design concepts. All figures in cubic metres per tonne of air dried pulp.

Various stages of the pulping process give rise to aqueous effluents in kraft mills. Comparative water usages at given stages and states of technology for bleached hardwood kraft pulp are given by Edde (1994) and these figures are reproduced in Table 5. These demonstrate quite clearly that whatever the design, the bleach plant effluents comprise a highly significant proportion of the total process effluent arisings. In the case of advanced future designs, the bleachery effluent will make up 71% of the effluent flow although the total volume generated per tonne of air dried pulp could be around a third of current levels.

Projected reductions in effluent arisings are likely to be achieved by extensive internal collection and recycling, and the diversion of some process effluents to feed other parts of the production cycle (Edde 1994). One of the key factors on which this depends is the quality of bleachery effluents and the degree to which they can be reused within the process and minimised in volume. Since chlorine and chlorine-chemical bleaching agents produce an effluent high in chloride they cannot be readily processed through the recovery cycle. The chloride ion, as hydrochloric acid is highly corrosive, giving the potential for leakage from the boiler tubes and the risk of serious explosion if water reaches the melt of minerals in the bottom of the boiler (McDonough 1992).

130 As noted by Albert (1995a) the only reason that process effluents are generated from a bleached kraft mill is due to the need to purge dissolved and suspended materials from the system which would otherwise inhibit production or affect product properties. If these can be dealt with through internal measures then closure of mill circuits and reduction of effluent volumes becomes feasible.

5.0 BLEACHING AGENTS and PROCESSES FOR CHEMICAL PULPS

The whiteness of produced pulp has traditionally been regarded as an index of quality not only within the industry, but also by the consumer. The whiteness of pulp is measured by its ability to reflect monochromatic light in comparison to a known standard, usually of magnesium oxide. Unbleached pulps exhibit a wide range of brightness values. Kraft pulp is generally dark brown in colour while sulphite pulps are a light yellow-brown.

The principal aim of pulp bleaching is to increase the brightness of the pulp. The chromophoric (light absorbing) components in pulps are predominantly functional groups of degraded and altered residual lignin which is both darker and more tightly bound to the fibres than the original lignin component (McDonough 1992). This can either be converted and stabilised (lignin preserving bleaching) or removed (lignin removing bleaching). In the production of dissolving pulps, the bleaching stage is also regarded as part of the refining process, helping to produce a pure pulp with high alpha-cellulose content. In the less highly refined pulps, bleaching is regarded as removing wood extractives and bark specks, and conferring superior strength characteristics. Mechanical pulps are bleached using oxidative chemicals, predominantly hydrogen peroxide.

131 TABLE 6. Bleaching chemicals and process short hand nomenclature from Fengel & Wegener (1989).

132 TABLE 7. Established pulp bleach sequences showing the predominant role of C12 and C102 in the industry.

133 134 TABLE 8. Pulp Bleach Sequences designed to reduce or eliminate the use of chlorine based compounds and chlorine from Fengel & Wegener (1989).

The chemical pulps are generally bleached using a multistage process of three to six steps, depending upon the pulp characteristics. Hardwood pulps generally require less bleaching than softwood pulps content. Sulphite and bisulphite pulps are more easy to bleach than kraft pulps, and can be manufactured entirely without bleaching with chlorine or its compounds although chlorine bleaching is used. The following text, therefore, largely considers the bleaching of kraft pulps which is the dominant production process on a global basis.since they have a lower lignin.

The historical use of bleaching chemicals in the pulp industry parallels their use in textile bleaching applications. In part this is due to early paper being manufactured from rags. The early bleaching of paper manufactured from non-wood fibres was carried out using sunlight (Farr et al. 1992). At the end of the 19th century, hypochlorite was introduced, and later elemental chlorine. In some cases, a combination of these chemicals was used and generally, an intermediate alkaline lignin extraction step was introduced (Fengel & Wegener 1989). Some commonly used bleach sequences together with the identifying keys used, are given in Tables 6, 7 & 8.

Table 6 shows the key role of chlorine and chlorine chemicals in traditional bleach sequences in the form of elemental chlorine or as chlorine dioxide and hypochlorite. Common industrial bleaching sequences are shown in Table 7. Table 8 shows non-

135 traditional sequences which are designed to reduce or replace chlorine. - Historically, in most commercial bleaching processes, chlorine bleaching is the first step carried out at a level of 3-4% C12 at 20-40oC for 30-60 minutes The residual lignin is converted to water- and alkali- soluble degradation products by the chlorine. This step is generally followed by an alkaline extraction step to remove these components. The final process steps involve the use of hypochlorite or chlorine dioxide.

Chlorine dioxide, despite handling difficulties, is largely replacing elemental chlorine in the initial bleaching stages. Its perceived advantages are: higher pulp brightness, improved fibre strength properties, lower chemical consumption and considerable reduction in the AOX of discharged effluents. Peroxide in combination with chlorine dioxide is often used in the later stages of bleaching chemical pulps.

Chlorine gas became a common bleaching agent in the first thirty years of the twentieth century (Reeve 1996). In conventional bleaching processes around 90kg of chlorine was used per tonne of pulp produced. This figure is stated to have now been reduced to around 25Kg per tonne and often to around 3-10 kg/tonne (RSAES 1989) although Kringstadt & Lindstrom (1984) state the chlorine charge to the pulp slurry to be between 60 and 70 kg per tonne of produced pulp. Chlorine dioxide was first used on a large scale in the 1940's and was first used in Sweden in 1947. This led to the multi-stage CEDED bleaching sequence which allowed high brightness products from kraft pulp without the loss of strength. The evolution of bleaching techniques has followed pulping process developments to a very large extent. In particular, the chemicals applied have changed as the lignin content of the pulps entering the bleach sequence has been reduced.

The historical aspects of bleaching developments are traced by Sodra-Cell (1996). A key factor was the development of oxygen bleaching in the process during the 1970's followed by use of oxygen in the alkaline extraction stages a decade or so later. Oxygen bleaching was inserted as a step after the digestion stage and allowed the lignin content of the pulp entering the bleach plant to be reduced from on average 5% to 2.5%. This effectively halved, the potential problem from the bleach plant effluent. In addition,

136 extended cooking time of the pulp in the digester also reduced the quantities of lignin entering the bleach plant and this was commercially demonstrated in the 1980s.

Substantial substitution of chlorine dioxide for chlorine has been known since the 1960's but became widely accepted during the 1980's as a result of growing concerns about the environmental impacts of organic chlorine compounds formed during chlorine bleaching. Complete substitution led to elemental chlorine free processes (ECF) becoming dominant first in Sweden and then in Canada and this is widely attributed to market pressures. Even so, cost considerations, particularly in the US appear to have inhibited the application of chlorine dioxide. Chlorine dioxide is relatively more expensive than chlorine with respect to the bleaching power per unit mass. Further development led to bleaching processes that did not use chlorine based chemicals (totally chlorine free or TCF). Development of hydrogen peroxide and ozone bleaching technology was an essential prerequisite of the commercial. feasibility of such methods.

Overall, various bleach sequences have been employed with varying degrees of chlorine substitution. Moreover, variation in the base technology means that a wide range of ECF processes in particular exist. This point is discussed further below.

6.0 FORMATION OF ORGANOCHLORINES BY CHLORINE BLEACHING

Due to the complexity of pulp mill discharges in chemical terms, it has become common to use various group parameters to characterise them. In addition to COD (chemical oxygen demand) and biological oxygen demand (BOD) the parameter of AOX is used to measure the quantities of organohalogens. AOX denotes adsorbable organohalogen compounds and the term adsorbable refers to the measuring technique used where the chemicals are adsorbed onto activated carbon before quantification by a combustion technique. Broadly, where chlorine chemicals are used, the quantity of AOX generated in kg per tonne of air dried pulp conforms to the following approximation:

137 AOX ❑ 0.1 (C12 charge + C1O2charge/5)

Considerable research effort has been expended on the detailed characterisation of pulp bleach liquors, a process only partly helped by advances in analytical techniques such as GC/MS (gas chromatography/mass spectrometry). This has shown effluents from pulp and paper bleach plants using chlorine to be extraordinarily complex. Suntio et al. (1988) published a compilation of over 250 chemicals present in pulp mill effluents. 180 of those listed are chlorinated compounds comprising phenolic, together with neutral and acidic compounds. The chlorophenolic compounds, particularly chlorophenols, catechols, guaiacols and syringols are important components and have, for example, been isolated from samples taken in every sub-basin of the Baltic Sea (Sodergren 1993). A proportion of these compounds appear to be derived from the degradation of high molecular weight chlorinated material formed during chlorine bleaching (Martin et al. 1995). It is only recently that reference compounds for some of these exotic chemicals have been synthesised for analytical purposes (Smith et al. 1994 a & b; HyotyIainen 1994).

Buser et al. (1989) identified a series of methyl-, polymethyl- and alkyl- polychlorodibenzofurans in pulp mill sludge and sediment which had previously been misidentified as polychloroxanthones and polychloro-xanthenes. van Loon et al. (1990) have described the analysis of chlorolignins in pulp mill effluent, although these were not quantified. A significant component of the high molecular mass compounds was identified as chlorolignosulphonic acids by van Loon (1992) in effluents discharged to the River Rhine. Chlorinated diones and enol lactones with mutagenic properties have been identified (McKague et al. 1988) while subsequent studies (McKague et al. 1989) have revealed the presence of trichlorothiophenes, compounds with significant potential for bioaccumulation. McKague et al. (1990) also identified chloroacetones at a number of mills. Low chlorinated PAHs present in pulp effluents were isolated by Koistinen et al. (1992) .

138 Elemental chlorine reacts primarily with residual lignin to produce approximately 4kg of organically bound chlorine per tonne of pulp produced, although this figure will vary according to the kappa number of the pulp being bleached and the specific bleach sequence. Various types of reaction mechanism can be involved and the diversity of such reactions is usefully described by Bergman et al. (1994). About 70% of the organically bound chlorine is present as high molecular mass material in spent liquor from the bleach. In the extraction liquor about 95% is bound as high molecular mass compounds with high carbon to chlorine ratios. Although these are thought, in themselves, to be biologically and toxicologically inactive, no data exist concerning the activity and fate of their degradation products. In addition, their high relative molecular mass coupled with their polarity renders them difficult to analyse by established chromatographic techniques (Kringstadt & Lindstrom 1984).

Around 30% of the organically bound chlorine is found in the spent chlorination liquor and 5% in the alkali extraction liquor as compounds of low molecular mass. Quantitatively, the most important is trichloromethane which may be produced in quantities of up to 40g per tonne of produced pulp. Trichloroethene, pentachlorobenzene and dichlorophenol are also produced in significant quantities together with a number of chlorinated phenolic compounds. Kallqvist et al. (1989) reported emissions of 5.7kg/hour of dichloromethane and 0.47 kg/hour trichloromethane from one pulp mill studied. A total of 119g/hour of various chlorophenolic compounds were also emitted. The derivatisation of pulp and paper effluent phenolics for analytical purposes is described by Lee et al. (1989) who considered the routine monitoring of these compounds to be important.

The biological impact of many of these chemicals remains unknown. There is now considerable evidence that metabolism and degradation of pulp mill derived organochlorines can considerably complicate an already complicated picture. For example, in a study of organochlorines accumulated by mussels in a bleach plant recipient at levels of 2045 ug/g AOX in the lipid fraction, only 1.1% could be related to identified organochlorines (Pellinen et al. 1994). Other work (Wesen et al 1990) demonstrated that between 10 & 15% of EOCI in fish can be related to known

139 compounds while in sediments the figure is nearer 5%. It is thought that in fish, large amounts of chlorine may be present in the form of chlorinated fatty acids whose origin is not known but may result from biological transformations of more complex chlorinated organic molecules.

Chlorinated phenols are known precursors of the polychlorinated dibenzo-p-dioxins (PCDDs) and the dibenzofurans (PCDFs). Consequently, the discovery of the chlorinated phenols in spent bleach liquor has led to pulp and paper plants being identified as sources of the highly toxic and bioaccumulative PCDDs and PCDFs. The industry is widely acknowledged to be one of the major sources for the contamination of aquatic systems in N. America and Scandinavia where most research has been carried out into the bleaching of pulp using chlorine compounds (Swanson et al. 1988; Whittemore et al. 1990). In addition to the chlorophenolics derived from wood, oil based defoamers have also been identified as precursor materials (see: Servos et al. 1995). The congener of principal interest is 2,3,7,8-tetrachlorodibenzo- -p-dioxin. This is the most toxic congener but other members of the group are also formed by chlorine bleaching. A study of a New Zealand wood processing facility (Campin et al. 1991) clearly demonstrates the role of chlorine bleacheries in the overall mass balance of PCDDs and PCDFs. In addition, contamination of the site with pentachlorophenol, originally used for sapstain control, was also identified as contributing to the overall dioxin loading to the receiving ecosystem.

Estimates made of organochlorine discharges from the Swedish industry in the 1980s, before process changes to ECF and TCF were widely implemented indicate that the quantities were extremely large. Wigilius et al. (1988) estimated that Swedish kraft mill effluents contained around 200kt of organochlorines corresponding to approximately 15kt of bound chlorine. It can been estimated on this basis that 5kg organically bound chlorine produced per tonne of pulp corresponds to a potential global discharge of 250kt of AOX. The actual mass of compounds discharged will be somewhat higher since empirical formulae range from C9H904C1 to C14H1008CI. Hence the chlorine comprises a low proportion of the relative molecular mass. On the basis of the Swedish figures, 250kt of organically bound chlorine represents around 3000kt of organochlorine compounds. This, of course, represents a worst case scenario. Nevertheless, the perceived

140 improvements in developed nations must be considered alongside the growth of pulping in developing countries where elemental chlorine is still very widely used.

Evidence mounted throughout the 1980s that mill discharges were responsible for increasing levels of organochlorines detected in receiving environments and a variety of ecological effects ranging from lethal effects upon marine macroflora to deformities and physiological abnormalities in fish. This led to a number of comprehensive and case specific studies being carried out (see: Sodergren & Wartiovaara 1988; Sodergren 1989; Sodergren 1993; Lindesjoo 1992; Forlin et al. 1995). These broadly confirmed the extent and scale of the ecological impacts of bleachery effluents from pulp mills and became highly influential in the formulation of regulatory policy worldwide. It has been estimated (Wulf & Rahm 1993) that around half the organochlorines produced by the Baltic pulp industry since the 1940s are still present in the sediments of the region.

In the North American industry, analysis of pulp mill wastes showed significant levels of chlorinated dioxins to be present. In bleached kraft pulp samples 2,3,7,8-TCDD and TCDF were found at levels ranging between 1-51 parts per trillion and 1.2-330ppt respectively. Primary sludge content ranged between 3.3 and 180ppt TCDD and 34-180 ppt TCDF. Levels in final effluent ranged between 3-120 parts per quadrillion for TCDD and between 7-2,200 ppq for TCDF (see: Harriman Chemsult 1989).

Bioaccumulation of the chlorinated dioxins and dibenzofurans in commercially important aquatic species led to the closure of several fisheries in Canada in late 1988 (Hocking 1991). The potential importance of local discharges upon fisheries and fish consumers may be assessed from the work of Svensson et al. (1991). They found that subjects graded as having a high fish consumption had blood levels of dioxins around three times higher than average consumers. The scale of the problems encountered is reported by Whittle et al.(1993). A case specific US study is described by Schell et al. (1993) while bioaccumulation of dioxins in a Canadian river system is described by Owens et al. (1994).

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As a result of the complexity of bleachery effluents in relation to their organochlorine content, there has been a trend towards monitoring their discharge by means of the group parameter AOX. AOX (Adsorbable Organic Halogens) measures the quantity of organically bound chlorine present in a sample. While useful as a process control monitoring index, it has important limitations which prevent its use as a predictor of environmental impact. The most obvious is simply that it gives no indication of the nature of the substances present (see eg Folke 1991; Neilson et al. 1991). Nonetheless, this parameter is a widely used index of the quality of pulp mill effluents.

7.0 POLLUTION CONTROL MEASURES

142 In the face of growing political and public concern, the pulp and paper industry began to research and implement ways of reducing organochlorine formation and discharge from mills reported as AOX in addition to COD and BOD discharges. These can be broadly categorised as process internal and process external measures. a) Process Internal Measures

Various process modifications have been implemented by the industry to reduce and contain spills arising from pulping and chemical recovery operations and these also lead to economic benefits by reducing chemical losses (Downs 1989). Nonetheless, these measures do not address the problem of bleachery effluents which account for a substantial proportion of total mill effluents.

Process internal measures to reduce mill organochlorine and other polluting outputs centre around increased removal of lignin before the pulp is sent to the bleach plant (see: Gullichsen 1991; McDonough 1992). Enhanced lignin removal allows modification of the bleaching process and agents and reduces the charge of bleaching chemicals used. In turn, this positively affects most bleach plant effluent quality indices, including BOD, COD, Colour and AOX. In part this can be achieved by improved washing of the brown pulp at various intermediate stages (brownstock washing). This gives a lower loss of lignin into the bleach plant. This is particularly true of washing after extended and oxygen delignification stages. In these cases the lower lignin content makes lignin removal of greater relative importance. i) Extended delignification

The degree to which lignin can be removed by extended cooking of the woodchips alone is limited. Over cooking results in a reduction of the strength qualities of the pulp (Minor 1982; Fengel & Wegener 1989). While AQ pulping with anthraquinone as an additive allows cooking to lower kappa numbers without loss of pulp quality, the additive is expensive and this has restricted its use. Extended delignification without strength loss can be achieved by ensuring that the alkali concentration stays as constant as possible throughout the cook (Gullichsen 1991). Using methods such as Modified Concurrent

143 Countercurrent (MCC) cooking or Rapid Displacement Heating (RDH) the lignin content of softwood kraft pulp can be reduced from.5% to less than 4%.

ii) Oxygen delignification

The use of oxygen in combination with alkali was first practised commercially in 1970 (McDonough 1992). It was first used in a pre-delignification stage to remove about half of the lignin from unbleached pulp. A great advantage of this process, is that unlike chlorine based bleach effluents, the effluent can be recycled, concentrated and sent to the chemical recovery system (Albert 1995a). This procedure is now widespread: most new mills and mill expansions include it while the use of oxygen to enhance the effectiveness of the first caustic extraction stage is regarded as almost universal.

Delignification is generally limited to between 40 & 50% since oxygen lacks the selectivity needed to take the process further. Accordingly, research has been directed at developing chemical pretreatments to improve oxygen selectivity and hence avoid pulp strength loss. An example is the PRENOX process (Gullichsen 1991), although this has not evolved to the stage of commercial development and application. Oxygen has become one of the main delignification technologies after steady growth during the 1980's and early 1990's (Hassi 1993) and according to industry figures (see: Reeve 1996 a & b) by 1994 some 50% of world capacity for kraft pulp incorporated an oxygen delignification stage. According to these figures proportional penetration of this technology is significantly less in the USA and Canadian industry as compared to the Scandinavian industry.

Improved delignification processes allow modification of the subsequent bleach sequence by reducing the quantities of chemicals required to produce pulps of the commercially requisite brightness.

iii) Modification of the Bleach Process

The second major area of process internal measures designed to reduce organochlorine generation is modification of the bleach sequence. Most organochlorines are formed in the bleach plant due to the action of molecular chlorine. Hence, elimination of its use will

144 yyr significantly reduce their formation. In 1990, chlorine used in pulp and paper treatment accounted for 5% of total chlorine use in Western Europe. Current figures suggest that in combination with water treatment, this sector accounts for around 2% of production. Over a similar time period, elemental chlorine use has fallen from 20% to 13% of the total chlorine market in the US reflecting similar, although markedly less pronounced, trends (Shelley 1990; Botha 1995).

Essentially, elemental chlorine has disappeared from use in Scandinavia. Bergman et al. 1994 state that it is no longer used in Sweden, although they note that large quantities are still used for pulp production in the US. Albert (1995a) notes that currently over 50 bleached kraft pulp mills worldwide are producing pulp without the use of elemental chlorine (ECF) and some 10 kraft plants are producing pulp without the use of chlorine chemicals (TCF). Albert (1994) lists over sixty mills producing TCF pulp. These figures, however, include sulphite and CTMP lines as well as kraft mills. The latest figures suggest that some 15-20 TCF kraft mills exist but not all are fully converted and use chlorine dioxide as a bleach agent on occasion.

Elemental chlorine use has been substituted to varying extents by chlorine dioxide in bleach plants. According to McDonough (1992) substitution of elemental chlorine by between 50 & 70% chlorine dioxide has been practised for a. long time but in relatively few mills. Chlorine dioxide has also been used widely in the final brightening stages of pulps at concentrations of between 0.1 and 1.2%. Figures provided by Gullichsen (1991) indicate that chlorine dioxide substitution of 90% will lead to AOX discharge levels equal to those achieved by extended delignification, oxygen and effluent treatment. Overall, in combination, these process modifications mean that whereas traditional processes discharge 5-10 kg of AOX per tonne of air dried pulp, mills may now discharge 1.5kg AOX/ADT.

The term ECF can embrace a wide range of process technologies. This has led to considerable confusion and debate in the technical literature as to the relative merits of ECF and TCF in environmental and marketing terms. A good example of poor use of data is furnished by AET (1996). The data show that ECF pulp production is rising faster than

145 for any other sector in the pulp industry and provides various quotes demonstrating that market demand for TCF is limited, and that the environmental impacts are equal to those of TCF. The counter argument is given by Gunnarsson (1995). This turns upon the fact that as of 1994 more than 50 mills of a total of 87 in the US were using old pulping technology without extended cooking and oxygen delignification.

Hence, the term ECF is • often applied both to pulp with a high kappa number likely to generate .large quantities of AOX and that produced with a low kappa number, implying that much less AOX would be formed. Overall, only 15 million tonnes of the total US ECF pulp production was produced using technology comparable to the TCF processes in Scandinavia. Partly as a result of the broad spectrum of ECF processes, and chlorine gas users present in the industry, discharges of AOX may range from 0.1 to 10 kg per air dried tonne, and the average value cannot be easily determined. It is stated elsewhere in the literature that without oxygen delignification and an extended cooking step, ECF bleaching alone will still result in AOX loadings of up to lkg per tonne of pulp produced (Axegard et al. 1993).

Albert (1995 a & b; 1996) has consistently argued that chlorine chemical bleach based processes, including ECF, are unlikely to meet the terms of emerging legislative frameworks. The proposed United States Effluent Limitation Guidelines apply stringent controls to AOX, COD, Colour, BOD and TSS. The original limits proposed in 1993 would indeed be difficult to achieve with chlorine chemical based technology. This industrial sector, is however, still under assessment and the proposals are being progressively modified. The final regulations to be applied are expected to be published in early 1997. Two options appear to be favoured for application in the industry. The first (A) is conventional pulping coupled with 100% chlorine dioxide bleaching while the second is oxygen delignification/ extended cooking and chlorine dioxide bleaching. These are outlined in more detail by USEPA (1995).

Hence, a substantial difference in AOX and COD discharge limitations can be expected depending upon the baseline technology. Unaccountably, despite the well documented capability of TCF processes in Scandinavia producing full brightness pulps, TCF has

146 apparently been excluded from the options for defining a Best Available Technology (SPPT 1996), although TCF mills could qualify under incentives packages proposed. The proposed 1996 regulations differ significantly from those outlined• originally in 1993. In particular, option (A) would result in AOX discharges almost three times those originally suggested in 1993.

Conversion to TCF processes has been intensively investigated and now seems established as the future system of choice for eliminating chloro-organics from the waste stream. In such processes, no chlorine chemicals are used, reliance being placed on bleaching agents such as peroxides and ozone. Research into the optimal ways of using agents such as ozone as bleach chemicals is being actively pursued (Mielisch et al. 1995) particularly with respect to carrying out bleaching at higher pulp consistencies thus reducing water usage. Other work has focussed on methods of optimising hydrogen peroxide bleaching (Axegard et al. 1996). b) Process external measures

Process external measures largely refer to the design and construction of various types of treatment plants. The balance of employed technologies varies between region. and include activated sludge plants (Saunamaki et al. 1991), aerated lagoons (Stuthridge et al. 1991; Stuthridge & McFarlane 1994) and anaerobic plants (Habets & de Vegt 1991). Almemark et al. (1991) suggests that in Sweden, solids from aerated lagoon treatment tend to be discharged to water, whereas in North America, Finland and Japan, where activated sludge systems are common, sludge handling is an important component of the waste management cycle from mills. The ability of treatment systems to reduce the AOX component varies markedly, but wastewaters discharged from such plant invariably contain AOX if chlorine based chemicals are used (Stuthridge et al. 1991) while sludges may contain up to 50g AOX per kg of dried material.

One aspect of the US proposed "Cluster Rules" is that it will no longer be permissible to remove contaminants from effluents and simply shift them to air, solid wastes or into products. This is of significance given the AOX residues likely to be found in sludges from various types of wastewater treatment plants as exemplified by a Swedish study

147 (Almemark et al. 1991). Biological sludge residue in aerated treatment lagoons ranged from 0 to 5 kg dry solids per tonne of pulp produced. This, in turn contained between 2 and 30g AOX per kilogram. In activated sludge processes, 5-25 kg of sludge are produced per tonne of pulp with a content of 10-25g AOX per kg. Chemical coagulation produces 4-80 kg of dried chemical solids per tonne of pulp and these solids contain 10- 40 g AOX per kg. These figures were derived for the Scandinavian industry prior to widespread process conversions in the late 1980's/early 1990's, but are likely to still be highly relevant to the industry elsewhere.

The actual disposal methods used for such sludges vary from country to country. In Scandinavia, incineration in the bark boiler was often used, while in the United States, landfilling appears to be the method of choice. Almemark et al.( 1991) note that relatively little work has been carried out on the environmental impact of the various disposal methods. Nonetheless, as a general phenomenon it is known that landfill leachates can contaminate ground and surface waters. Moreover, organochlorines have been found in the flue gas of bark boilers used to incinerate sludges and chlorinated liquors and in the fly ash generated by these operations (Kopponen et al. 1994). These include the chlorinated dioxins and dibenzofurans. Sonnenberg and Nichols (1995) demonstrated that adding small amounts of El concentrate containing chlorine to black liquor increased emissions of hydrochloric acid and that PCDD and PCDF emissions increased by a factor of ten with a 1% addition of bleach plant effluent to black liquor. The spiked black liquor was combusted in both a laboratory scale plant and in a small pilot incineration plant.

Treatment of bleach plant effluents can reduce toxic effects, depending upon the bleach chemicals used and the type of treatment employed, while the move towards chlorine dioxide as a bleach chemical has also contributed (Rosemarin et al. 1990). It has .become clear that the biological activity of pulp effluents may persist through conventional treatment processes. For example, a highly treated effluent in Australia was reported significantly to induce liver MFO activity in carp. Induction was poorly correlated with organochlorines extracted from the fish muscle, but appeared to be positively correlated with PCDD and PCDF levels measured in muscle (Ahokas et al. 1994). A further problem is associated with the use of chlorine dioxide. This is the potential discharge of chlorate, a potent herbicide to which marine brown algae are particularly sensitive (Rosemarin et al. 1990; 1994). Discharges from the Swedish Monsteras mill in the early 1980s caused the brown alga Fucus vesiculosus to disappear from an area of 12 km2. While this problem appears to have largely been. solved through modified effluent treatment (Landner et al. 1994), the situation outside of Scandinavia is unclear.

Finally, nutrient loadings to receiving waters are also of importance, and treatment plant is being designed to minimise emissions of nitrates and phosphates (Enell & Haglind 1994). In areas such as Austria, such plant has operated for some years, although as in Germany, the industry is based more or less exclusively on sulphite technology (Kroiss 1994).

8.0 EFFECTS OF PROCESS MODIFICATIONS ON ORGANOCHLORINE PRODUCTION a) Non-dioxin compounds and AOX

There is little doubt that process internal modifications in particular have sharply reduced the quantities of organochlorines (see: Table 9) discharged from bleached kraft pulp mills. This is reflected both in studies of effluents and of recipient waters, but even where bleach sequences have been modified, if they involve chlorine based chemicals then organochlorines are discharged (Palm & Lammi 1995). For example, in a study of two Finnish mills which eliminated elemental chlorine from the bleach sequence and substituted chlorine dioxide, sharply reduced emissions (but not elimination) of the toxicologically important chlorinated cymenes was reported (Rantio 1995). Further work has shown that levels of chlorinated cymenes and cymenenes emitted from a mill employing complete chlorine substitution were higher than from a mill where substitution was only partial (Rantio 1996a & b). This implies that variations of within-mill systems may be highly important. In another Finnish example, levels of chlorinated PAHs in mill wastes and products were lower in birch pulp produced without elemental chlorine as compared to pine pulp bleached with elemental chlorine at the initial stage (Koistinen et

149 al. 1994a). Koistinen et al. (1994b) also reported chlorinated fluorenes and alkyfluorenes in birch pulp bleached with chlorine dioxide, but at lower levels than in elemental chlorine bleached pine pulp.

A further Finnish study conducted analyses of levels of trichloracetic acid (TCA) in pine needles situated downwind of a pulp and paper mill using only chlorine dioxide in the bleach plant (Juuti el al. 1995). The study found a clear correlation between levels of TCA and distance from the mills with the highest levels found close to the mills. TCA is formed from the chlorohydrocarbon precursors. While the mills were clearly implicated as the source of this compound, the study was conducted only a short time after process conversion, hence the contribution of chlorine dioxide to the phenomenon is unclear.

TABLE 9: Effects of process internal measures designed to increase delignification of softwood kraft pulp on the quality of the bleachplant effluent. Figures before and after anaerobic treatment are shown. Kappa number can be converted to percentage residual lignin estimate by dividing the figure by six. Table reproduced from Gullichsen (1991). Bleach sequence given as CD-Eo-D-E-D.

150 Where partial substitution of the initial chlorine charge with chlorine dioxide has been practised, untreated effluents have been found to have significant mutagenic activity and the ability to cause chronic liver injury (Metcalfe et al. 1995) although carcinogenic effects in fish were apparently absent. Mutagenic agents were also detected by Rao et al. (1994) in a mill effluent where a high degree of chlorine dioxide substitution was employed. It is, however, not clear in either case to what extent the observed effects were due to .organochlorines or to non-chlorinated wood derivatives. Similarly, in studies of bleaching of eucalypt pulp 70% chlorine dioxide substitution considerably reduced but did not eliminate the production of chlorophenolics, chloroform, chloroacetones and chloro-dimethylsulfones (Smith et al. 1994c).

In a US study, chlorine dioxide substitution of 60-70% (Haley et al. 1995) resulted in only a 12% decline in AOX levels although chlorinated resin acids, chlorinated phenols, chlorinated guaiacols and catechols were all reduced in the effluent by much higher percentages. At a New Zealand mill with aerated treatment lagoons and using full chlorine dioxide substitution, elevated levels of chloro-phenolic compounds were identified in the river and riverine sediments which received the effluent. Background levels of chlorophenolics were achieved approximately 20km below the mill (Judd et al. 1995). b) Chlorinated dioxins and dibenzofurans

A follow up to the US 104 Mill study (Gillespie 1996) has shown that discharges of chlorinated dioxins have been substantially reduced. Reductions are thought to be due not only bleach process changes, but the replacement of defoaming agents made from oils with a high aromatic content and contaminated with non-chlorinated dibenzo-p-dioxins and dibenzofurans as noted by Servos et al. (1994). The total relevance of the US study is open to question, however, since only the 2,3,7,8-TCDD and TCDF isomers have been considered. Other isomers are formed in chlorine bleach operations (Campin et al. 1991; Servos et al 1994). In a study of chlorinated dioxin accumulation in fish exposed to mill effluents and employing varying degrees of chlorine dioxide substitution showed that in general the highest levels were found close to• mills with lower percentage substitution

151 and lower intensity of effluent treatment. The importance of historical inputs was not clear but could have been a confounding factor (Servos 1994).

Rappe & Wagman (1995) analysed brownstock, ECF and TCF . pulp and identified 2,3,7,8-TCDF in chlorine dioxide bleached pulp but at levels very much lower than previous reports in the literature. This is tentatively attributed to the formation of free chlorine from the chlorine dioxide. No effluents were tested in this study. Nonetheless, air sampling at a Finnish mill converted to bleach using only chlorine dioxide detected elevated levels of several chlorinated dioxins and furans, with the furans being the dominant components (Rosenberg et al. 1994). In addition, levels of 1,2,3,4,6,7,8- HpCDF, the dominant furan in the air samples, were higher in the blood of a group of workers at the mill than in the background population (Rosenberg et al. 1995).

Results of monitoring for chlorinated dioxins and dibenzofurans are available for the Champion Pulp Mill, Canton, North Carolina at various points in the effluent treatment process. According to Gleadow et al. (1996) this mill has two bleach lines applied to pine and hardwood pulp, using full chlorine dioxide substitution. Of the analytes determined, 2,3,4,6,7,8-heptachloro-dibenzo-p-dioxin was found in the influent to the waste treatment plant, the sludge from the treatment plant and in the leachate from the sludge. 2,3,4,6,7,8- HexaCDF was present in effluent from the treatment plant. 2,3,4,6,7,8-HeptaCDF was detected in effluent, sludge and leachate and 2,3,7,8-TetraCDF was detected in the sludge.

152 ...... ::. (BP) ...... ::::. ::::::..:::::::::.:01 :.::::::.:...::::::::......

TABLE 10: Concentrations of chlorinated dioxins found in whole mill effluent expressed as Nordic Toxic Equivalents. The bleach sequences for each plant are shown. Effluent was as follows: A: untreated, B: untreated, C: aerated lagoon, D: untreated, E: activated sludge, F: untreated, G: aerated lagoon (pilot), ECF-1: untreated, ECF-2: aerated lagoon, ECF-3: untreated, excluding rinse, ECF-4: untreated, including rinse, ECF-5: aerated lagoon, ECF-6: bleachery, ECF-7: bleachery, aerated lagoon, ECF-8: untreated, ECF-9: aerated lagoon.

On the basis of quarterly testing, the presence of these compounds was found to be variable. It is not clear whether Octa-CDD and Octa-CDF were tested for in this study. These results suggest that industrial claims that ECF alone can fully address the problem of chlorinated dioxin generation within the process may be over optimistic. In addition, a recent Swedish study investigated the concentrations of chlorinated dioxins in whole mill effluent from a number of mills using different bleach processes (Miljo93 1995). These results clearly show that chlorinated dioxins and dibenzofurans of toxicological significance are present in the wastewaters from a number of mills employing partial and complete chlorine dioxide substitution.

Hence, while chlorine dioxide substitution appears to reduce dioxin discharges, they appear to be present at detectable levels, in contradiction of the North American view that these process internal changes reduced them below detection limits (Gillespie 1996). The potential production of 2,3,7,8-TCDF is also recognised in the USEPA "Cluster Rule" proposals where an effluent limit of 24. 1pg/l is suggested (SPTT 1996).

153 It is clear from the limited number of studies carried out on mills employing partial and full chlorine dioxide substitution, with or without oxygen delignification, that while AOX discharges may be reduced by such process internal measures, they are not eliminated. Neither is the production of toxicologically significant dioxins eliminated.

9.0 CHLORINE AND CHLORINE DIOXIDE LINKAGE

It has been suggested by Rappe and Wagemann (1995) that the explanation for. chlorinated dioxins found in brownstock was due to the presence of elemental chlorine in the bleaching gas. Reeve et al. (1995) established that decreasing the pulp consistency, increasing the pH or reducing the chloride ion at low pH all tended to reduce AOX discharged with the effluent. The Swedish study Miljo93 (1996) found chlorinated dioxins present in ECF effluents. These findings suggest that ECF is an incorrect term due to the inevitable presence of elemental chlorine. Hence ECF processes cannot correctly be described as chlorine free under existing definitions. For example, The Confederation of European Paper Industries (CEPI 1992) has published the following definition of ECF:

ECF (Elemental Chlorine Free) refers to a pulp bleaching process which does not use chlorine gas.

Elemental chlorine can be present in chlorine dioxide through two routes. Production of chlorine dioxide is accompanied by the co-production of elemental chlorine. All commercial processes are based upon the reaction of a reducing agent with sodium chlorate. This may be hydrogen chloride, sodium chloride, sulphur dioxide or methanol. The sulphur dioxide process (Mathieson process) produces less elemental chlorine than other reducing agents (Clapper 1978; McDonough 1992). A proportion of the elemental chlorine can be absorbed in the scrubbing tower used to prepare the bleaching solution. In systems using chloride as the reducing agent, the chlorine dioxide may have up to 15% by weight of chlorine (Rapson & Strumila 1979). Where a sulphur dioxide based system is used, the produced chlorine dioxide can contain between 1 and 5% elemental chlorine (Kaczur & Caulfield 1994).

154 Fredette, (1996) notes that where sodium chloride is used in the R2 process, it produces around 0.6t of chlorine per tonne of chlorine dioxide. Approximately lg/l appears in the chlorine dioxide solution while the balance is used to manufacture hypochlorite. Virtually all R2 units were sold in the Southern United States. Subsequent R series and SVP series plants were designed to reduce waste acid output, but increased levels of 2g/l of chlorine were present in the chlorine dioxide solution. Eventually, hydrochloric acid based systems were developed. This could be made from the by produced chlorine. Even in plants using methanol, chlorine is not eliminated due to the need for chloride ion to be present in the reaction mixture. In the R8 process 0.1 g/l of chlorine are present in a solution of lOg/l of chlorine dioxide. Hydrogen peroxide processes which can eliminate the chlorine by-production entirely are limited by the high cost of using peroxide in these processes. CEFIC (1993) also recognise the by-production of chlorine in chlorine dioxide generation. Reeve (1996b) notes that with the R2 & R3/SVP producing a lOg/l chlorine dioxide solution, 10% of the oxidising equivalents are provided by chlorine.

Even if this problem of chlorine by-production is solved, free chlorine is also generated during bleaching with chlorine dioxide as noted by Rapson and Strumila (1979) and Reeve et al. (1995) Hypochlorous acid is generated as an intermediate. Chlorine dioxide reacts with the pulp to produce bleached pulp and chlorous acid. A pH dependent equilibrium then becomes established between the chlorous acid, chlorite ion and hydrogen ion. The concentration of chlorous acid becomes lower with increase in pH value. Chlorous acid is highly reactive towards lignin and in the course . of the reaction is reduced to hypochlorous acid. In the presence of chloride ion, the hypochlorous acid enters into another pH dependent equilibrium with free chlorine being evolved. This free chlorine is available to produce chlorinated organic compounds measured as AOX. Hence,"elemental chlorine free", where this means "molecular chlorine free" is not true of any bleach sequence involving chlorine dioxide. Gaseous chlorine is inevitably evolved either in the production of chlorine dioxide or in the pulp mixture to which it is applied. Ultimately, therefore, it appears that only those commercial processes entirely free of chlorine chemicals as _bleach agents merit the term of elemental chlorine free.

155 10.0 BIOLOGICAL IMPACTS OF MILL DISCHARGES-RECENT RESEARCH

Recent research work has established that even with reduced AOX discharges, mill effluents can exert significant impacts upon the receiving environment. Some follow-up work to the original Swedish studies (Sodergren 1989; 1993) have been conducted upon receiving environments for bleached kra$ pulp mill effluents in order to gauge the effects of conversion from elemental chlorine to other bleaching agents. These have generally shown that following process changes, some recovery of the environment takes place but this is not complete. Sandstrom (1994) reported on abnormalities in fish populations exposed to mill effluent. Following the introduction of chlorine dioxide at the Norrsundet Mill in Sweden, some abnormalities were no longer recorded. Nonetheless, the abundance of adult perch was low and high levels of larval mortality and low embryo quality were recorded in the area within 1-2km of the mill.

Kankaanpaa et al. (1995) investigated the effect of effluent from a mill using 100% chlorine dioxide in the bleach process upon the behaviour of an ecologically important Baltic Sea amphipod. The effluent contained 8.3mg/l AOX. Negative impacts were observed upon swimming activity in the test animals following exposure to the effluent at AOX levels diluted to between 150 and 400 micrograms per litre. Kovacs et al. (1995) found that secondarily treated effluent from a plant employing 45% chlorine substitution for elemental chlorine suppressed reproduction in test fish.

Effluent from a mill using 70% chlorine dioxide substitution caused induction of liver mixed function oxidase enzymes, an index of pollution stress, in largemouth bass. Effluent concentrations of 8% and 4% effluent were used in artificial streams. Even after oxygen delignification was installed and full substitution of the chlorine by chlorine dioxide, enzyme induction resulted in fish exposed to 4% and 12% effluent in artificial streams (Bankey et al. 1995). Similar findings were made for trout exposed to effluent from a mill employing increased chlorine dioxide substitution (Haley et al. .1995) and a positive dose response relationship was observed.

Suppression of immune parameters was recorded in roach exposed to effluent from a mill employing 25% chlorine substitution in Finland (Jokinen et al. 1995). Further subtle

156 effects were identified in a comparative Canadian study which revealed that fish exposed to bleached kraft mill effluent showed reduced investment in reproduction, reduced gonad size and reduced fecundity when compared to fish taken from an uncontaminated site (Gagnon et al. 1995), although the precise bleach sequence was not given in the study. More intriguingly, the short term growth of mayfly larvae was stimulated by exposure to effluent from a bleached kraft mill in Canada (Lowell et al. 1995) leading the authors to speculate that chemicals acting upon the insect endocrine system could be responsible. An apparent stimulation of fish growth in the short term is also apparent from the work of Haley et al. (1995).

Comparison of low level, long term effluent toxicity between mills using a variety of bleach processes has shown that effluents derived from elemental chlorine bleaching are indeed the most toxic. In a study of structure of artificial ecosystems exposed to mill effluents, the least structural disturbance was recorded in the system exposed to bleachery effluent from a fluff pulp mill using an OPD bleach sequence. Intermediate disturbances were reported from effluent exposures where partial chlorine dioxide substitution was used in the initial bleaching step after an oxygen delignification step, for example, O(C85+D 15)(EO)DED. The most serious disturbances were reported in systems exposed to effluent derived from a CEHDED sequence (Tana et al. 1994).

These observations have been generally confirmed in the industry (Axegard et al. 1993) where lowered chlorine charge has resulted in reduced impacts. In mills using chlorine dioxide, AOX levels have been reduced further. There appears to be no correlation between AOX discharge levels and environmental impact, a phenomenon noted also by Tana et al. (1994) in their studies of specific responses of fish. In addition, other observations (Barker et al. 1994) have documented a variety of lesions in fish sampled adjacent to a mill using sodium hydrosulphite as a bleaching agent, with no chlorine chemicals in use.

Grahn & Grotell (1995) reported that some environmental impacts were significantly reduced when totally chlorine free (TCF) bleach processes were used in comparison to ECF processes using chlorine dioxide, confirming earlier work (Lovblad & Malmstrom

157 1994). Kovacs et al. (1995) reported that the overall toxicity of effluents tested in a bioassay was untreated ECF> untreated TCF> secondary treated ECF> secondary treated TCF. In previously published studies noted by Kovacs et al. (1995), the differences between TCF and ECF derived effluents were less marked. They note that generalisations regarding a particular process and the subsequent effects upon the mill discharge are difficult to make.

One particular problem in making comparisons stems from the wide range of potential ECF processes discussed above. Comparisons are strictly only valid when comparing low kappa ECF after chlorate ion removal with TCF effluents. A further complication in comparing between studies is the fact in some of these mill effluents were synthesised in the laboratory rather than taken from real mill operations. These were subjected to various non-standard treatments and were, therefore, not representative of the products of the different and complex reactions occurring within the mill. This fundamental criticism can be levelled at, for example, the work of O'Connor et al. (1993) which is widely cited as evidence of ECF effluents being less toxic than TCF effluents.

One study found a high acute toxicity of untreated TCF effluent and this was identified as due to residual hydrogen peroxide. The toxicity could be removed completely by biological treatment. The treatability of the effluents produced by TCF processes in comparison to wastewaters from chlorine gas and chlorine dioxide bleaching of softwoods was investigated in the same study. Activated sludge treatment reduced the COD of TCF effluents by 55-65% as against 35-45% for wastewaters containing chlorine compounds. Similarly, chemical flocculation produced positive 85% removal of COD from TCF wastewaters (Saunamaki 1995).

One key concern in relation to TCF mills is the use of chelating agents to control metal build up in the processes which could affect peroxide and oxygen bleaching. The degree to which these could affect metal mobilisation in the wider environment is not clear but could be significant. The concentrations of metals present in TCF wastewaters have been found to be higher than in other bleachery effluents, probably due to the EDTA content.

158 The EDTA is also responsible for raised nitrogen emissions and, in common with DTPA, does not readily degrade under biological treatment.

Overall, such studies demonstrated that while environmental improvements could be achieved by process changes and that the elimination of chlorine based chemicals was a key factor in such improvements, effluents from all processes were toxic to some degree. Indeed, these and similar findings led to increasing suspicions that chemicals other than the AOX components present in pulp and paper effluents were at least partially responsible for observed changes in fish populations. It has been known for some time that acute effects of pulp effluents were attributable to resin and fatty acids released from the processed wood. These components present in the effluent of a thermomechanical pulp mill were found to be lethal to trout after 2-4 weeks exposure at a two hundred fold dilution (Johnsen et al. 1995). Analyses of resin acids in the fish showed a positive dose- response correlation.

Resin acid contamination in sediments was found to correlate with significant behavioural modification in benthic invertebrate species (Hickey & Martin (1995). The resin and fatty acids from wood, however, are considered to be largely removed by biological treatment (see: Owens 1991) while Zender et al. reported a 96% removal of these components by secondary treatment in a New Zealand plant. The greatest mass flow was from the foul condensate stream and extraction bleaching stages.

An extensive study of Canadian mills using a variety of pulp production processes revealed that physiological changes in fish exposed to effluent were associated with significant effects upon reproductive development. These effects were also associated with changes in liver mixed function oxidase activity. Moreover, the effects were recorded at very low effluent concentrations and the causative agent or agents were not removed during normal secondary treatment. Significantly the observed effects did not correlate with AOX levels in the effluent or levels of dioxins and furans (Carey et al. 1992). These studies have subsequently been reported in considerable detail. The precise relevance of MFO induction measured as ethoxyresorufin-O-deethylase (EROD) is open to question in view of recent research showing that temperature can strongly influence

159 the induction of this enzyme and the cytochrome P4501A system in marine fish species as well as exposure to xenobiotic chemicals. (see: Eggens et al. 1995; Sleiderink et al. 1995 a, b & c). Even so, MFO enzyme activity was induced in fish living in the recipients of most mill wastewaters examined.

The mills studied are described, together with the receiving water characteristics, by Robinson et al. (1994). All discharged in excess of 40,000 cubic metres of effluent per day and included bleached kraft producers and sulphite/mechanical pulp mills. Induction of liver MFO enzymes and depression of plasma sex steroid levels were identified downstream of several mills including some without chlorine bleaching and with advanced secondary treatment (Munkittrick et al. 1994). Other responses such as reduced gonad size and enlarged livers were also found in fish near mills using chlorine and mills using no chlorine chemicals. The effects in feral populations could not be predicted from the results of laboratory toxicity tests on a variety of species. As noted above, there was no apparent correlation with PCDD/PCDF levels and changes in physiological parameters or the biomarkers used with the exception of EROD induction. PCDD and PCDF levels were, however, higher near mills using elemental chlorine than those using other bleach agents or no bleaching at all (Servos et al. 1994). 2,3,7,8-TCCD toxic equivalence levels were strongly and negatively correlated with testosterone levels in fish of both sexes (Heuvel et al. 1994).

11.0 ENDOCRINE DISRUPTION & PULP AND PAPER MILLS

The findings from the Canadian research programme coupled with observations made in the Baltic sector focussed attention on natural plant components, particularly those capable of interfering with the endocrine systems responsible for hormone synthesis and metabolism. Landner et al. (1994) suggested that natural sterols present in the wood such as ❑ - and ❑ -sitosterol could be a factor since administration of these compounds to fish induced similar responses to pulp and paper mill effluent exposure. This theme was also taken up by Tana et al. (1994) who noted that a proportion of these chemicals extracted from wood would not be cycled through the recovery process, but would be passed to the bleach and effluent treatment plants.

160 The current situation is analogous to that prevailing after regulatory initiatives to control BOD and COD discharges in the 1980's and before. Removal of BOD from effluents led to improvement in recipient quality, but allowed the identification of effects due to other agents present in discharges, specifically organochlorines, which had previously been obscured. Progressive reduction of organochlorine loading similarly, has allowed the. identification of yet further impacts due to other chemicals. (see: eg. Owens 1991).

In fact, laboratory studies as early as 1941 had established that it was possible to masculinise .mosquito-fish using artificial hormones. It was reported in 1991 that androstenedione, androstanol and spironolactone could achieve the same result. In 1978 it had been reported that phytosterols present in tall oils recovered from wood could be converted by microbes to steroids. Tall oil consists of 25-25% phytosterols. Hence, the total phytosterol production by this route alone in the US was estimated at 20,000 tons. (see: Davis & Bortone 1992). These same changes can be produced by exposing fish to kraft mill effluent, although the authors do not specify whether this was derived from a chlorine chemical bleach line.

As a result, there are now two distinct elements to the debate about environmental protection from pulp and paper operations. The Canadian findings have prompted the industry into large scale questioning of the utility of reducing AOX emissions any further. For example, Myreen (1994) cites the opinion of scientists in the Nordic countries and Canada that reductions of organochlorines below 1.5 kg AOX/ADT pulp represents an inefficient use of resources. The precise basis for this view is obscure.

Malinen el al. (1994) advance a similar viewpoint in their analysis of the future of the industry in Finland. The views subsequently diverge markedly. While Malinen et al. (1994) propose the development of treatment plant to address the residual problems, Myreen (1994) considers that total effluent free (TEF) production is now accepted by the industry as the decisive step towards environmentally friendly pulp and paper production. In light of the Canadian findings and the realisation that all pulp mills can emit endocrine disruptive chemicals on a large scale, closure of the mill circuits may be seen as an environmental imperative for the industry, a theme taken up and discussed by Albert

161 (1995b). In most geographical areas there appear to be clear present and likely future environmental, market and fiscal incentives to move towards TEF production.

12.0 TOTALLY EFFLUENT FREE PROCESSES-CLOSING THE BLEACH CIRCUITS

Currently, zero effluent operation appears to be restricted to plants producing bleached chemical thermal mechanical pulp and non-chlorine bleaching agents (Edde, 1994). As noted earlier, the bleach plant is the major source of contaminated effluent in a kraft pulp mill. Hence closure of these circuits is an essential prerequisite for producing a zero- effluent kraft mill. Myreen (1994) points out that this requires the simultaneous resolution of a number of problems. These include water balance, chemicals balance, corrosion, precipitation of salts and removal of non-product substances. Development work is being directed at closing both ECF and TCF bleach circuits. Closure of the bleach plant circuits implies a large scale increase in the levels of organic and inorganic matter in the process liquors and filtrates which need to be accommodated (Krotscheck et at. 1995).

Albert (1995a) provides a cost breakdown for a reference kraft mill in relation to an effluent free plant based on ozone and peroxide bleaching which has considerable capital and running cost advantages. This allows for the re-use of all process waters in the brownstock circuits and the chemical recovery circuits. In addition to significant chemical cost savings, there is no need for capital investment in primary and secondary effluent treatment plant. A closed cycle TCF plant does not require substantially different recovery boiler design (Gleadow et at. 1995) but may involve the treatment of purge lines to control potassium and chloride levels entering with the mill furnish. Moreover, a recent analysis (Laxen & Henricson 1996) has shown that TCF processes are economical in terms of the energy used in the generation of ozone.

Due to lower chloride levels in the process liquors, TCF processes undoubtedly have an advantage over ECF processes since the chloride introduced is from the mill furnish alone. ECF bleach plant effluents contain high levels of chloride ion from the bleaching reaction in addition to non-process sources. A major problem is corrosion as noted by

162 Edde (1994) due to the presence of corrosive chloride salts. D stage filtrates are also highly acidic, exacerbating corrosion problems (Manolescu et al. 1995). If ECF circuits are to be closed therefore, some means of dealing with both the chlorinated organics and inorganic chlorides is required. Most proposed systems include an incineration step (Myreen 1994; Manolescu et al. 1995). Incineration has been suggested both for evaporates and filtrates from the bleach line and for organochlorine containing sludges from wastewater treatment plant. Other suggested systems such as flocculation followed by electrodialysis are at an extremely early stage of development (Johansson et al. 1995).

The incineration of organochlorine wastes has been shown to produce and emit a wide range of organochlorines of toxicological significance. This is due to the reaction of organic fragments with hydrogen chloride and free chlorine gas in the process, particularly in the gas phase. These compounds include the chlorinated dibenzo-p-dioxins and dibenzofurans together with chlorinated phenols and benzenes (see: eg Cains & Dyke 1994; Wienecke et al. 1995; Heeb et al. 1995; Jay & Stieglitz 1995).

Combustion of air dried concentrates from ECF processes has been shown to evolve both hydrogen chloride and free chlorine in pilot studies (Manolescu et al. 1995). Sharply elevated levels of PCDDs and PCDFs were formed in a laboratory scale combustion furnace by incinerating black liquor with 1% chlorine bleach effluent added (Sonneberg & Nichols 1995). PCDDS and PCDFs were isolated from a number of flyash samples derived from the experimental combustion of bleached kraft mill primary and biological sludge mixed with bark (Kopponen et al. 1994). Similar emission considerations apply to proposals to route ECF waste streams through the recovery boiler, which in addition will require boiler design to be adapted to tolerate higher chloride levels (Gleadow et al. 1995). The incineration of chlorinated bleach plant wastes is likely to prove a significant barrier to the closure of ECF bleach lines. This is due both to the technical difficulties involved and a growing lack of public acceptance of incineration processes generally. In addition, the inevitable presence of organochlorines in the sludges and other process wastes is likely to fail the test of the USEPA "Cluster Rule" (Albert 1995b) under the original 1993 proposals.

163 Precise cost estimates for construction and operation of a new zero effluent bleached kraft mill using ozone as compared to a standard mill using chlorine dioxide have been generated by Albert (1995a). A TEF mill constructed on this basis would incur capital costs of $585 million as against $625 million for an ECF plant. Operating costs for the TEF mill would be $58 per ADT as compared to $93 per ADT for a standard mill. In the case of converting an existing mill, the distinction is less clear, but the balance still favours TCF processes. To close an existing ECF mill operating on chlorine dioxide could incur costs of $98 million with incremental costs of $3 per ADT. To convert to TCF would cost $96 million with incremental costs of -$2 per ADT (Ricketts 1994). These estimates are recognised to be variable and site sensitive, but nonetheless favour TCF processes. Significantly, the largest cost element associated with conversion of an ECF mill is combustion plant for acid filtrate concentration and incineration.

164 Conclusions

1) Reuse of partially treated waste water on land for irrigation purpose for integrated pulp and paper units to be one of the practical methods. But this requires careful planning, pre irrigation studies and environmental management. The paper and pulp mills are generally small industries with limited financial investment and can not afford to have elaborate treatment units. The oxidation ditch if suitably designed and operated at optimum level can treat the waste effectively for disposal into water courses, if in plant measures are taken there will be considerable reduction in the pollution load and waste water volume. 2) Industrial projects have profound influence on society and environment, resulting in benefits, risks and hazards. They bring in their wake the concomitant ills of environmental pollution, depletion of resources, over crowding, effects on human health, desecration of forests and aesthetic nuisance. Adverse impact on environment results because of indiscriminate and unregulated exploitation of both renewable and nonrenewable resources in the environment, and the use and abuse of environment as a sink for dumping the waste products of developmental activities. India is on the threshold of development. During this critical period, an environmentally compatible development need be evolved. An analysis and assessment of the environmental impacts arising out of a development project provide the necessary guide lines for siting, systems modification if any, during construction and operational phase, choosing the degree and type of control for pollutant emissions and environmental management.

3) Data have been reported from different parts of the world on the nature of organic compounds present in black liquor, waste waters from pulp washing chlorination, alkali extraction etc. and their toxicity to the fish and other aquatic fauna and flora. However, no work carried out in this regard in India. Apart from toxicity, some compounds present in pulp and paper mill waste waters show mutagenic effect i.e. a change in genetic code of the living cell. It has been found that only the chlorination stage wastes produce significant mutagenicity which decreases

165 almost linearly with increasing substitution of chlorine dioxide for equivalent chlorine for bleaching. Chlorination of pure lignin as well as ground wood, kraft and sulphite pulp also produced mutagenicity. The lignin component of the pulp appears to be responsible for mutagenecity. Fortunately much of the mutagenecity is lost when waste water ph is raised to 7-8 as it is the normal practice, before discharging bleach plant wastes to the treatment plant or in to receiving water. 4) The major polluting constituents in pulp and paper and rayon pulp mill waste waters are suspended solids, colour, foam, inorganics, BOD and COD. They also contain appreciable quantities of toxic organics and inorganics. Lignin and its derivatives impart colour and exert high toxicity. Discharge of untreated wastewater into water courses will damage the water quantity and the colour would persist for long time. Paper mills are located all over the country and only few of them provide treatment. No river is spread from pollution due to these wastes. 5) During cooking of wood chips in kraft pulping a part of sodium sulphide reacts with lignin and carbohydrates in wood to form malodorous sulphur compounds such as hydrogen sulphide (H2S) Methyl mercaptan (CH3SH) dimethyl sulphide (CH3SCH3). Other gaseous emissions include oxide of sulphur (SOX) and nitrogen (NOX). The particulate emissions include sodium sulphate and carbonate from recovery furnace.

Sodium compounds and calcium carbonate are discharged from the flue gases of lime kilns. Suspended particulate matter (SPM) are also released from auxiliary power generation plant in the paper mills. Both H2S and organic sulphides are extremely odorous and are detectable at a few parts per billion concentration. Odour is one of the principal air pollution problems in kraft paper mills. 6) The problem of air, water and solid waste pollution in pulp and paper industry in India are being tackled as follows : Liquid effluents : Research institutes and other research universities have developed anaerobic digestion in which the black liquor or the Brown stock wash effluent is digested in an anaerobic lagoon with the detention period of 6 to 10 days. Generally

166 abandoned mines or dry ravine beds are used for constructing these lagoons. The inlet and outlet arrangements are simple pipes with earthen embarkments. Aerobic : Successful results have also been obtained by aerated lagoons for general paper machines wastes. The BOD reduction by both anaerobic and aerobic systems are up to 80-85%. The rayon grade pulp effluent from sulphate process has also been treated successfully by anaerobic process using detention period of 12 days with 60% to 70% reduction in BOD and about 80% reduction in suspended solids. Colour removal from board mill and straw board factories have been obtained by use of open field irrigation or through the run on grass fields. Reduction upto 60% have been recorded. Small straw board factory : Black liquor disposal fas been successfully obtained by use of earthen drying beds. Black liquor volumes upto 150 mm can be dried within a period of 5 weeks during dry summer months. This gives area requirements of approx. 10 sq meters per thousand liter of effluent. f) The disposal from the paper machine or board machine has also been tried successfully by land irrigation. Work has also been done on large mill with 200 ton/day successfully using experimental irrigation both on laboratory and on plot scale. The study showed that wheat or paddy can grow by the effluents successfully with the same yield as normal water irrigation. The results of irrigation for a period of 2 years have shown that approx. 25 ha. Can be irrigated per 20000 cuc. meter of waste water for wheat and twice the amount for rice. These treatment disposal methods have been very successfully used in many pulp and paper mills in India but one aspect of removal of colour is still not solved.

7) In order to promote sound environmental practice and move towards zero effluent mills, environmental regulators need to promote the need for process changes. Extended cooking and oxygen delignification of pulps is required to reduce the quantities of lignin entering the bleach plant. The bleach plant should be based upon totally chlorine free technologies to reduce effluent toxicity as much as possible and to facilitate water and process chemical recycling without need for incineration of sludge contaminated with

167 organochlorine compounds. Under these conditions, the mill circuits can effectively be closed and operated totally effluent free (TEF).

8) The present operation of the closed cycle mill has been 100% successful in fully recycling all process streams it can certainly be stated that the concept is proven and viable. The difficulties which one encounters in controlling a process of this size and complexity is difficult enough without adding to the problem by the necessity of balancing numerous flows. It is credit to this company that they have almost fulfill these demands.

9) Seeing the performance datas, it can be confidently stated that the effluent treatment measures adopted by the Orient paper mills, Amlai is most effective in reducing the pollutants waste water. 10) Due to lower chloride levels in the process liquors, TCF processes undoubtedly have an advantage over ECF processes since the chloride introduced is from the mill furnish alone. ECF bleach plant effluents contain high levels of chloride ion from the bleaching reaction in addition to non-process sources.

11) Substantial substitution of chlorine dioxide for chlorine has been known since the 1960's but became widely accepted during the 1980's as a result of growing concerns about the environmental impacts of organic chlorine compounds. formed during chlorine bleaching. Complete substitution led to elemental chlorine free processes (ECF) becoming dominant first in Sweden and then in Canada and this is widely attributed to market pressures. Even so, cost considerations, particularly in the US appear to have inhibited the application of chlorine dioxide. Chlorine dioxide is relatively more expensive than chlorine with respect to the bleaching power per unit mass. Further development led to bleaching processes that did not use chlorine based chemicals (totally chlorine free or TCF). Development of hydrogen peroxide and ozone bleaching technology was an essential prerequisite of the commercial feasibility of such methods. 12) An integral and economically vital part of alkaline pulping mill operations is the regeneration of the cooking liquors (Fengel & Wegener 1989; Minor 1982). The recovery cycle is well defined for the kraft process and is designed to recover pulping chemicals, reduce water pollution by combusting organic matter in the spent liquor, generate process heat and recover by-products of value. The main steps in the process are the evaporation of the black liquor drained from the digester after wood chip digestion, combustion of the concentrated liquor to produce a mineral "smelt", causticisation of the smelt and regeneration of the lime used in the process. The energy content of the black liquor is high. Gullichsen (1991) notes that half of the wood is dissolved during the manufacture of chemical pulp, and this, when combusted in the recovery boiler, provides heat for the plant systems.

The heart of the process is the recovery furnace. The black liquor is evaporated to a solids content of between 60% and 75% using a 5-6 stage system and this is followed by direct contact evaporation in which flue gas from the recovery boiler is brought directly into contact with the liquor. Tall oil soaps are recovered during the evaporation stages. Oxidation of the liquor prior to evaporation can be carried out to reduce the emission of malodorous compounds. When the black liquor is concentrated, sodium sulphate and other chemicals are added to compensate for those lost in the pulping process.

In the recovery boiler, the organic content is combusted to produce heat. Carbon dioxide reacts with sodium hydroxide to produce sodium carbonate. The added sodium sulphate is reduced to sodium sulphide and hence the solid smelt produced by the boiler contains largely sodium carbonate and sodium sulphide. This is dissolved in a tank to produce the green liquor which is subsequently filtered and treated with calcium hydroxide (slaked lime) to convert the sodium carbonate to sodium hydroxide. The resulting white liquor is then returned to the digestion process. The lime is regenerated by heating and mixing with water removed from the green liquor. This process is, therefore, theoretically closed in relation to water use but not with respect to atmospheric emissions, spills and condensate generation.

169 The pulps produced by the kraft process are characterised by good strength properties. They are, therefore, the preferred grades in strong paper grades such as the liner in corrugating boards or bag and wrapping papers. Hardwood kraft pulps are used in many printing papers for bulking purposes, in mixture with softwood pulps. The residual lignin present in the pulp is expressed in terms of the "kappa number" which is determined by the oxidation of lignin by potassium permanganate under acidic conditions. The lower the kappa number of a pulp, the lower the level of residual lignin.

170 RECOMENDATIONS It has been emphasized that the mode of treatment and disposal of an effluent from an individual unit should specially be chosen taking in to consideration all factors like location, process, economical conditions, land availability, the condition of receiving water source and other possible modes like for those needed for agricultural use etc., rather than the insistence on a particular quality of an effluent. Pollution control regulations are a right step in the direction to regulate industry to meet their obligations towards society. A clean . and healthy environment is vital for the survival and welfare of the human being. In view of the implementation being capital intensive, it is however ensured that the growth of the industry is not hampered and economy affected adversely. The laying down of regulations and formulation of the standards is essential but their true implementation has to be practical and in a phased way taking into consideration the relevant factors involved. India is on the threshold of development. During this critical period, an environmentally compatible development need be evolved. An analysis and assessment of the environmental impacts arising out of a development project provide the necessary guide lines for siting, systems modification if any, during construction and operational phase, choosing the degree and type of control for pollutant emissions and environmental management. Industrial development and environment are linked to each other. It is apprehended that the environment is adversely affected the growth of industry. This relation in today's context -seems to be justified while visualizing the effect of waste discharges in the surroundings and its effect on ecology. Development is a need of the society but at the cost of environment may not be acceptable. There has to a sustainable development where environmental aspects have also to be considered with growth of the industries. Paper industry fortunately is based on renewable sources of raw materials and creates a product which is biodegradable. The paper manufacturing cycle is sustainable. Although, the cycle for wood based raw materials (bamboo, eucalyptus) is lengthy but the cycle for agro-based raw materials is renewable every year and is generated in abundance from the agricultural fields. The wastepaper is also recyclable for making paper again. The pollution problem from pulp and paper industry need to be addressed carefully. The pollution. roblem in wood based pulp and paper industries agro-based pulp and paper industries are different in nature. The wood based pulp and paper industry have better

III sustainable approach while the most agro-based pulp and paper mills lacks in this respect. The better environmental practices adopted by wood based (large) mills • are mainly on account of financial capability, better infrastructure, skilled man power, R&D support and better management practices. Most of theagro-based pulp & paper mills (small) are literally insensitive towards addressing environmental issues due to obsolete equipments, poor man power, poorly managed approach and lack of willingness which leads to damaging effect on environment. Three, major sources of air borne emissions are from liquor preparation, cooking and chemical recovery, both particulates, gases and odour are involved. The air borne wastes from sulphate pulping consists mainly of: i) Particulates from the: a) Recovery furnace, composed of sodium sulphate and sodium carbonate plus carbon particles. b) Lime klin, composed essentially of lime dust. c) 'Power plant, composed of flyash, soot or unburned bark, depending on the fuel used. ii) Mists from the : a) Recovery furnace b) Lime klin c) Dissolving tank d) Causticizer e) Digester f) Blow tank iii) Odours and Non - odourous gases from the: a) Recovery furnace, composed essentially of sulphur dioxide and hydrogen sulphide. b) Lime klin, containing smaller quantities of the same two gases. c) Power plant, consisting of sulphur dioxide if the furnace being operated properly. d) Digester relief, containing inorganic and organic sulphur compounds, such as hydrogen sulphide, methyl mercaptan, dimethyl sulphide, and dimethyl disulphide. e) Blow tank, containing the same compounds. 172- f) Turpentine recovery ( not used in India) • g) Evaporators, consisting of hydrogen sulphide, methyl mercaptan, dimethyl sulphide, and dimethyl disulphide. Other sources are active, but those mentioned are believed to be the major ones. In terms of volume, the off gases from the recovery furnace make this the major source. Digester relief gases, blow gases, and the off gases from the evaporators represent a considerably smaller volume, but have a potentially higher nuisance value. The effects of fallouts like fly ash, soot, lime, wood particles create aesthetic nuisance and deposition of dust on near by habitation. Vegetation damage. may result from sulphurdioxide and fallout of particulates. Smaller particles are carried long way resulting in visibility interference and carry odour to long distance. Paint especially lead based discolouration due to hydrogen sulphide is one of the common complaints. Odours due to sulphur compounds are also caused in the vicinity of pulp mills. Control can be considerd by providing cyclones, precipitators or scrubbers for particulate, and collection and oxidation of blow gases and digester release gases. Odours are in seperable from the process. Odour free operations will depend on the methods for retaining them in the system or converting them to innocuous substance, cost effective technologies are developed. The small paper and board mills in India (up to 30. tonnes per day) consume on an average 220 to 410 m3 of water per tonneof product, and an integrated mill (100 tonnes per day and above) consumes 300 to 425 m3 of water per tonne of product. The pollution load per tonne of product from small units is higher than that of a large mill, where recovery and reuse of chemicals from black liquor is practiced. The problem with the wastewaters is its high BOD, COD and suspended solid content, dark coloration and relatively high sodium content. Colour and COD in waste waters are the most difficult problems requiring solution by cost effective technology which are not yet available. The practicable methods.should aim at providing in plant controls, recovery of chemicals and fibers, segregation of streams, and recycling of treated waste waters wherever feasible. Utilisation of partially treated effluent for farming can be considered, but this requires detailed pre-irrigation studies of soil character, proper choice of cropping and scientific irrigation and environmental management. Normally,. irrigation is limited to coarse textured soils. Low cost treatment methods have to be evolved for small sized

173 plants (20 to 30 tonnes per day capacity). Application of the waste water with or without treatment on land will lead to deleterious effects due to high sodium. Anaerobic lagooning in earthen basins and holding black liquor in earthen lagoons should be discouraged as they result in ground water polloution and odour problems. Another related, aspect is the problem of disposal of solid wastes, especially mud. The quantity of lime sludge produced will be around 1.25 to 1.70 tonnes per tonne of paper on wet basis, while on dry basis, it will be 0.5 tonnes per tonne of paper. At present, these are dumped on follow land. During rains, these are partly washed in to natural water courses or spread on land. Availability of sufficient area of land also poses problem. Cost effective methods to recover lime after silica removal from sludge need be evolved. In order to minimize environmental damage, a systematic environmental impact analysis and assessment should be carried out for site locations. The potential pollutants from a pulp and paper mill fall in to four principal categories as -under : (I)SOLID WASTES: a) Sludges from primary and secondary treatment and causticizing in kraft mill recovery section. b) Solids such as grit bark and other mill wastes. c) Ash from coal fired boilers. The gaseous emissions are released from digesters, chemical recovery furnace, steam boiler, H2S, S02, S03 malodorous gases (like mercaptans, Dimethyl sulphide, Dimethyl Disulphide). The ordor problem in kraft mills is essentially due to reduced Sulpher compounds. (II) WATER EFFLUENTS: a) Suspended solids including bark particles, fiber, pigments, dirt and the like. b) Dissolved colloidal organics like hemicelluloses, sugars, lignin compounds, alcohols, turpentine, sizing agents, adhesives like starch and synthetics which create BOD load. c) Colour bodies, primarily lignin compounds and dyes. d) Dissolved inorganic such as NaOH, Na2SO4, bleach chemicals etc. e) Bleach plant effluents (TOCI, AOX, TODD, BOD, COD etc.). f) Thermal loads. g) Microorganism such as coliform group. 17L h) Toxic chemicals if present. (III) PARTICULATES: a) Fly ash from coal fired power boilers. b) Chemical particles primarily Na and Ca based. c) Char from bark burners. (IV) GASES: a) Inodurous Sulphur gases such as mercaptans and H2S released from various stages in Kraft recovery furnace and lime kiln. b) , Bleach plant emissions, C12, C102, 03, Chloroform etc. c) Steam since it can be hazardous when visibility is impaired/lime kilns containing particulate matters.. d) Other NCG (Co, CO2, Hydrocarbon, H2S, HCI, HF etc.). Emissions rates, kg/tonne pulp from a chemical pulp bleaching are as under: C12, : 0.1-3, C102 :0.1-1 and S02 :0.1-1.

l7s GENERAL BIBLIOGRAPHY

1. www. serfing. net 2. James P. Casey, Pulp and paper, Chemistry and chemical technology, third edition Volume III, January 1981 3. Subramanyam, P.V.R. and Hanumanulu, V. Economics of Waste water treatment in small paper mills,IPPTA,XIV, 127(1976). 4. Leach, J.M. and Thakore, A.N. `Identification of the constituents of kraft pulping effluent that are toxic to juvenile Cohosalmon, J.Fish Res.Bd.Canada, 30, 479(1973) 5. Rapson, W.H., Anderson, C.B. , and Reeve, D.W. , "The effluent free bleached kraft pulp mill, Part VI-Substantial substitution of chlorine dioxide for chlorine in the first stage of bleching" Pulp and Paper Canada 78(6) : T- 137 (June 1977) 6. Pattyson, G.W. , Rae, R.G. Reeve, D.W. Rapson, W.H. , " Bleaching in the closed cycle mill at Great lakes forest products" paper presented at the 1979 International pulp bleaching confrence, Sheraton center, Toronto, Ontario. 7. Wolverton, B.C. and Mc. Donald, R.C. NASA Technical Memorandum 1977 8. Tiwary, K.N. and Jivendra, IPPTA XVII (2) : 35(1980) 9. Performance of waste water treatment plant at O.P. Mills, Amlai page 191, International seminar on Management of environmental problems in the pulp and paper industry1982. 10. Literature referance, publication of SSVL 11. Ramanathan, N.L., and Parabrahmam, M. "Environmental issues pertaining to pulp and paper industry, Industry and environment, Vol. 3,No. 4, Dec (1980) 12. Ray A.K, "Paper mill pollutants, their monitoring and measurement techniques" IPPTA Journal volume 18, Number 4 Oct—Dec 2006 page no 45. 13. IPPTA proceedings "Environmental Management in Pulp and Paper Industry" December 1994. 14. Pollution control acts, Rules and Notifications issued there under, CPCB, Delhi, 5`h Edition, 2006

17( 15. Ansari P.M. Key note address on cooperate responsibility for environmental protection (CREP) in pulp and paper industries IPPTA Journal volume 18, No 4, Oct-Dec, 2006 16. N.Sarma, S.N. Nath and N.D Rajkhowa " Environmental- Safeguard Through Implementation of CREP", IPPTA Convention Issue, 2004, 33 17. Akira Yoshitake, Motoki Sakashita, "A new suction-roll shell material for highly aggressive paper mill white water environment", Vol.76, No.1 Tappi J, 91 18. Gitanjali Chaturvedi, R.K Jain, K.Singh and A.G. Kulkarni "Indian Paper Industry-Grpwth and Prospects", IPPTA J. Vol. 18, No. 2, Apr-Jan, 2006,76 19. Reid Miner, Jay Ubwin, "Progress in reducing water use•and wastewater loads in the U.S. paper Industry" August1991, Tappi Journal, 127 20. Nikhilewar Sharma and H.Charkravarty "Towards Cleaner Production: Nagaon Paper Mill" IPPTA Conversion issue, 2006,123 21. K.S. Rajesh, M.C. Faizur Rahman " Scientific Approach of Water Management and Conservation", IPPTA Convention Issue, 2004, 51 22. N.Sarma and N.D. Rajkhowa "Pulp and Paper mill wastewater characteristics and its Impact on the quality of ground water in the neighboring region", IPPTA Convention Issue, 2004, 85

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