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BIOGAS from HUMAN WASTE Workshop Held in Delhi

BIOGAS from HUMAN WASTE Workshop Held in Delhi

3 5 2. 1 87 BI FROM HUMAN Workshop held in Delhi. August 22-23. 1986.

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CONSORTIUM ON RURAL TECHNOLOGY

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BIOGAS FRÖM Workshop held In Delhi. August 22-23. 1986.

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CONSORTIUM ON RURAL TECHNOLOGY

— 1 1 1 1 1 1 1 1 1 1 1 1 © Copyright by Consortiumon Rural Tecbnology First Publishedm 1987

Price Rs: 100.00 U.S.$ 25 1 1

Published by Consortium on Rural Technology D-320, Laxmi Nagar, Delhi - 110 092 Phone 224-4545

Designed & Prirned by 1 West Coast Litho Systems Pvt. Ltd. Delhi. 1 1 1 1 CONTENTS

Introduction Y.K. Sharma 1

Prologue Shailendra Nath Ghosh III

Keynote Address Maheshwar Dayal 3

BACKGROUND PAPER

Blogas from human wa.ste Shanta Satyanarayan, S.N Kaul, 9 S D. Badrinath, S K Gadkari

SOCIAL ASPECT

Nlghtsoil based biogas plant: Lis role in social equality and community benefits and the problem of its social acceptance Savitri Madan 23

Social aspects of nightsoil biogas Ishwarbhai Patel 26

‘3uh1iî~l~1 ~ÎEIT~t~ 29

Social aspects of the nightsoil blogas plant , programme through case studies Krishna Mahapatra 30

Blogas plants based on nlghtsoil Amulya ChakraborLy 32

HEALTH ASPECT ‘ ‘

Nlghtsoil Blogas plants: Health aspects S.R Kshirsagar 37

Nlghtsofl biogas plants: Health aspects and design H.N. Chanakya 44

Biogas from Nightsoil: The health aspect and design S.M Navrekar 52 Nightsoil based biogas plants: A useful device for

rural health and development S.V. Mapuskar 59

Health aspects of anaerobic Yashwant Singh 65

Health and Hyglene Issues Rajamal P. Devdas, Lakshmi 66 Santa Rajagopal, Ghanambal Jagadeesan

Blogas from human waste: Public health and social aspects DR. Gupta 68

DESIGN AND R&D ASPECT 1

Design aspects of biogas plants fed by LK. Sinha human excreta with or without suppiementary feedstocks N.B. Mazumdar 73

Design of biogas plant on nightsoil RahulParikh 74

Nlghtsoil-fed biogas plants: Basis for design AnilDhussa 78

Nlghtsoil based blogas plants: Timetested design-floating dome on water jacketed digester SV Mapuskar 81

Design and Implementation of a pilot demonstration community nlghtsoil blogas Anil Dhussa scheme Raymond Myles 86

Soine aspects on the design of family-size flxed-dome nightsoil biogas plants Anjan K Kalia 91

Improved ilnicages of latrine complex to community biogas digester S.K.Vyas 98

Malaprabha latrine bloga.s plant: A new innovative design for utilization of biogas from latrine S.V. Mapuskar 99

Nlghtsoil biogas plants: Health aspects and design H.N Chanakaya**

Blogas from nlghtsoil: The healthaspects and design S.M. Navrekar

**Thesepapersdealbot!, wit!, bealth and design aspects These have beenprinted under bealth aspects. Pleasereferto that sectionfor these papers. 1 TREATMENT OF SLURRY AND ITS USE

A.C. Gaur from anaerobic treatment of human waste 105 KC. Khandelwal

Biogas plant effluent handllng and utlilsation Anil Dhussa 110

~T~ï 116

STRATEGY FOR PROMOTION AND JNTEGRATION WITH OTHER DEVELOPMENT PROGRAMMES

Nightsoil based bi~as plant strategy for promotion and Integration wlt.h development projects H N. Todankar 121

Promotlonal strategy on biogas programmes N B. Mazumdar, 123 Yashwant Singh

Strategy for promotion of blogas plants from human waste In rural areas Raymond Myles 124

ILECOMMENDATIONS 127

EPILOGUE Shailendra Nath Ghosh 133

LIST OF PARTICIPANTS 149

INTRODUCTION

YK Sbarma~/Secretary Consortium on Rural Technology INTRODUCTION

Biogas plants have been accepted by now in the country~as a device for improving the quality of the life of the people. They help in of the cattie and produce both fuel and manure from the same quantity of dung. At present it is understood that over 3 million families own biogas plants plants in the country. The majority of these biogas plants use cattie dung as the feedstock. At the same time there are efforts to also use alterna-tive feedstocks like human excreta, and also other agricultural wastes, water hyacinth etc.

The safe disposal of night—soil/human excreta is of major consideration for any sanitary programmes and one of them can be through feeding It into the biogas digesters.

It is agreed that the use of the gas from the nightsoil will be considered taboo by the majority of our people. But at the same time there are many who have accepted it more at ~ndividuaI level than at the community level.

Some of the community biogas plants direcily fed on human excreta are at Masoodpur village near Delhi; Sewagram, Wardha; Midnapur (West Bengal) and Puri in Orissa.

The gas produced from the plants established in Orissa and Midnapur is utilised for purposes by the scheduled caste of community. Its use also produced the worst kind of reaction from the beneficiaries because the worst kind of reaction from the beneficiaries because the ground-work that was needed to be done for educating the people does not seems to have been done bef ore installation of such plants. This means if awareness and education programme is carried out before supplying this gas for cooking, it may not only be used by the scheduled caste but also by others increasingly. At the same time night-soil can be a very good alternative feedstock especially where cattie dung is not available, as in our urban areas. Such areas can be where large number of people reside at one place like school/college hostels, hospitals, police lines, Army units, Jhuggi-Jhopri colonies etc. etc. Some of~theproblems that come to mmd ar~

1. In fed biogas plant, what would be suitable mix of feeds and in what proportion.

2. How much of water should be added to the different kinds of feeds (so far as dung is concerned it is at 1 : 1 ratio)

3. On what basis would the digester be planned-on the basis of summer or the winter “ 1f the summer temperature is taken as a basis for the design, will not the gas production suffer in winter ? 1f it is based on winter temperature will

not the digester volume have to be very large - and hence dernanding a higher BIOGAS FROM HUMAN WASTE

surface area and higher costs.

4. What are the practical measures to prevent heat loss from the digester during the night in winter ‘~ 1 5. What models would be preferable, floating dome of the KVIC model or a fixed dome of the 3anta type ? 1

6. What kind of repairs, how often and involvingwhat kind of service will be required ‘~ Will the service be available locally ? 1 7. What should be the arrangement for the post-digestion of the slurry ? Should the effluent slurry be dried on sand feds or stored in lagoon pits or aerobically composted 1 with other organic materials ? 8. Since the biogas plant fed with human excreta is required to be near the latrmne 1 and also near the kitchen and yet at least 50 feet away from the water sources, there was a problem of reconciling these requirements.

9. How far should the slurry be stored so that it does not have the other problems. 1 Considering the various problems associated with biogas plants fed fully or partially with human excreta. The Consortium in collaboration with Actmon for Food Production (AFPRO) invited a workshop on biogas from human waste. A small working group to decide on the various issues associated with the subject was constituted. The folowing f ive aspects of the nightsoil biogas plant were identified and institutions and individuals working on the were invited to the workshop. These aspects are:- 1. Social aspects 1 2. Health aspects 3. Design and R&D aspects 4. Treatment of Slurry and its use 5. Strategy for Promotion and Integration with other Development Pro’~rarnmes The workshop was held on August 22nd and 23rd, 1986. The keynote address was 1 delivered by Prof. Maheshwar Dayal, Secretary, Department of Non-conventional Energy Sources, Government of and the background paper was presented by the scientists from NEERI - National Environmental Engineering Research Institute, Nagpur. Such a workshop was very much welcomed and it generated a lot of interest and interaction between scientists and the social action groups. It was participated by about 75 participants 1 drawn from Government Departments, Research Institutions and Voluntary Organisations. Based on the presentations, the papers, discussions and the recommendations made on the different issues referred above, 1 The proceeding and the papers of the workshop have been edited by Sri Shailendra Nath Ghosh. We are also grateful to him for writing the prologuc and the epilogue. 1 We hope that the publication of proceedings of Conference would be found useful and generate further interest in the subject. 1 1

II - 1 PRØLØGUE Shailendra Nath Ghosh In order that the benefits of the discussions do not remain confined to the enciaves of specialists, it is necessary to explain a few fundamentals of -the biogas-cum-manure plant operation. Biogas is ob-tained from of biological source material or (i.e. organic waste) in a biological process. Since we are interested in gas which can serve as cooking fuel, produce light, and drive stationary engines, the biolo- gical agents have to be the methane producing which function only in an atmos- phere fçom which has been excluded (anaerobk bacteria). In the presence of oxygen, the decomposing organic matter produces oniy . Airtightness is crucial to biogas plant functioning. This makes exacting demands on masonry skill. Vol-taile solids content of the input is important~~Tt ~ the portion of a sample which can be burnt off and which represents the amount of organic matter really avail- able to the bacteria for their own nourishment and conversion into gases and single-ceil protein biomas. Although a small paz-t of the volatile solids (such as , hair, feathers) is usually non-digestible or very slowly digestible, volatile solid is the digestible or very slowly digestible, volatile solid is the basis for calculating the gas potential and determining the loading rate and retention time. The non-volatile part of the input represen-ts that portion of a sample which is left as ash when burnt. It is also called fixed solids. For anaerobic biogasification, the necessary nutrients are carbon, and phosphorous. Of these, the •ratio between carbon and nitrogen is important because It is the carbonaceous matter which is converted to gas and -building materials, and any nitrogen other than what is required by the bacteria will end up as which, when excessive, will be toxic to the bacteria. Organic ma-terial with a C:N ratio higher than 30:1 v~i1l produce a raw gas with less methane*(1) and more carbon- dioxide, while a C:N ratio substantially lower than 30:1 will produce excessive ammonia and supress methanogenic bacteria. In international literature, there seems to be a difference of opinion. Some western sources say that the C/N ratio of 30:1 is the best for methane production. The Chinese sources say that this should be between 20:1 and 25:1. Indian scene has no opinion on this mat-ter. Nightsoil being low in C/N ratio-between 5:1 and 7:1 needs to be suppiemented by other materials which are high in callulosic content and low in nitrogen, such as excremen-t of herbivorous animals, fallen leaves, fresh grass, vegetable staiks, garbage etc. In rural areas, where such materials are abundant, it should not be difficult to bring -the mixed feed to the optimal C/N ratio. But this requires a fair knowledge of the C/N ratio as different kinds of materials available in the locale. China’s scien- tific bodies have made available to Chinese farmers the carbon/nitrogen ratios of the common materials usable in biogas digesters. It should be the responsibility of our scientific bodies and our Universities and colleges to contribute such knowledge regarding materials specific to each locale. The process of producing methane-rich gas involves a series of reactions in which three types of bacteria take part. These three types are : (i) the hydrolysing bacteria which transform the compounds into solubles and the heavy particles into simpler one ,so that these can be attacked by others; (ii) the acidogenic bacteria which convert

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1~- - .------~ -~-—.-- ,------~ i~-~M i BIOGAS FROM HUMANWASTE the broken-down organic matter into organic acids, principally ; anc~ (iii) the methaneogenic bacteria which take up the acetic and convert it into methane, carbon dioxide etc.

Since a balance has to be maintained between these three stages, the rate of loading has to be duly observed. 1f the organic mat-ter is added too rapidly, the hardy and quickly multiplying acidogenic bacteria will grow even faster and produce a surfeit of volatile acids, lowering the p1-! of the slurry to the detriment of the methanogenic bacteria.

The pH level of the digester slurry is a crucial factor. It is a measure of the acidic or basic (i.e. alkaline) nature of the slurry. What is the optimum pH Ievd -- on this question, there seems to be some difference.

According to some researchers, “the methogenic bacteria generally funcion in in the pH range of 6.4 to 7.5. with 7.0 or neu-tral p1-! being the optimum point”. Accor- ding to a Chinese source, “the environment must be kept either at the neutral pH level or at sligh-tly alkaline”. According to still another Chinese source, “ideally, the pH in a pit should be a little on the alkaline or neutral, with a pH of 7.0 to 8.5”. Possibly a pH of 8.5. is tolerable with cattiedung as mnpu-t, whose potential for ammonia produc- tion is low. With nightsoil as an input, this level is risky. We can exclude the extremes 1 of pl-1 6.4 and pH 8.5 from our consideration and seem to maintain pH between 7 and 8. Significant deviations from this will mean digester failure. Low pH will mean acid toxicity and high pH will mean ammonia toxicity to methane producing bacterial. This is the reason why it is necessary to frequently check and adjust the pH of the liquid. 1 The question is : how can a lay person check and adjust the pH. “A Chinese Biogas Manual says: 1

“The method of checking is simple. (1) Dip a piece of litmus into some of the liquid, immediately observe the change in colour, and compare this with a chart of colour to teil the pH of the liquid. (2) The people of Sichuan have observed that a red or yellow flame in the gas generally corresponds to slight overacidity in the fermentation liquid”.* 1 When this is observed, “one should remove some of the old material and replace it with a compensating amount of new material, or add some lime or ash, to adjust 1 the acidity and restore normal gas production”. Temparature is a key factor in biogas plant operation. It is universally accepted 1 (i) that the level of temperature decides not only the killing rate of pathogens but also which group of methaneogenic bacteria will function in the digester. Although it is true that thermophilic range of temparature (48-60°c) kills the pathogens quicker, improves gas yields and completely diges-ts the slurry in a shorter detention period, it loses its justification on the ground that produc-tion of this order of temperature requires input of external energy. Moreover, the thermophilic methanogenic bacteria are more sensi-tive to variations in the environment. Mesophilic methanogenic group of bacteria, which functions at 30-40°c range, is mor~.suitable for household or commu- nity biogas plants. A constant range of temparature is important. A sudden rise or fail by even 2-3°Caffects the methane forming bacteria.

iv 1 BIOGAS FROM HUMAN WASTE

Although generally the above two temparature ranges are mentioned in literature on biogas, the Chinese sources say that in Sichuan Province, they depend for fermenta- tion on the ordinary temparature of 10-30°c. An IRDC publication, too, reporting on the experience from the same province, says: “After operating for more than a year, it was found that normal production can be achieved by keeping the temperature at 20°c~ During the summer and autumn the tank’s temperature averages about 23°c and plenty of biogas is produced; in winter when range from 0 to 7°c the tank’s temperature stays at about 10°cand biogas is stil! produced.

This should raise the question: why, then, do we find it so difficult to run biogas plan-ts even at temperatures ranging be-tween 13°c and 23°c ? Does this necessitate any pre-treatment of the “feedstocks” in India’s northernmost regions, particularly

in winter - as is done in the temperate regions in China ? The discussions that follow are intended to answer these questions plus those that have been raised in the Introduc- tion.

(l)* Biogas produced by anerobic, decomposition, generally, consists of 60-10% methane. The remaining 30-40% is combination of carbon dioxide, sulf mde and other gases.

(2)* Human excreta is rich in nitrogen. Its nitrogen content is 5-7% as -~compared with 1.7% in cattie dung. Human urine contains about 18% nitrogen.

*Those who prefer testing by a Chemical may draw a small quantity of slurry and put 2-3 drops of phenol phthalene.

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KEYNOTE ADDRESS

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KEYNOTE ADDRESS

MaheshwarDayal Secretary/Dept. of Non-Conventional Energy Sources, Ministry of Energy, Govt of India

At the outset, 1 would like to congratu— is declining with declining forest cover late the Consortium on Rural Technology and increase of population. (CORT) for taking the initiative in organi- sing this workshop on Biogas from Human Realising these difficulties, Govern- Wastes. Not only the prospects of biogas ment has taken up an integrated programme generation from human was-te will be of settirig up rural latrines during the discussed but also the problem areas. 7th Plan. It is expected that 80% of This is all the more important at this the urban areas and 25% of the rural juncture when Government of India is areas would have sanitary facilities by embarking in a major way on irnplementing the year 1990. Effective management an integrated action plan for rural sanita- and proper disposal of the human waste tion and when a major thrust has been will be required at all times. given for energy generation from renewable sources. As you are all aware, worldwide effect is continuing for development The severity of the problems relating and use of alternate and to inadequate sanitary facilitates in rural sources. The production of biogas, in and urban areas hardly needs any emphasis. this context, is gaining greater attention. The latest statistics available reveal The success of generating biogas from that only 0.72% of the rural population cowdung and other animal wastes had have access to sanitary facilities. The led to exploration of alternate material situation in urban areas is not much as sources of biogas production, including better as 33% or more of the urban popu- human waste, sludge, agricultural lation have no facilities worth wastes and industrial wastes which conta-in the name. The obvious result is that organic matter etc. A number of agencies people have perforce to use open fields, inciuding non-governmental organisations farm land, ponds, flowing streams, streets, have taken up the establishment of biogas railway tracks etc. Consequent to increase plants based on nightsoil either as a in population, industries, urban centres, supplementary feed or exclusively as and transport facilities the abovementioned feed material. Utilisation of nightsoil traditional options have more than reached for biogas generation is advantageous the limits. Apart from the direct and and some form of its treatment is obliga- obnoxious effects such as foul smeil, tory from social and health points of pollution and filth, the untreated human view. Biogas plant enables production waste causes disease, mosquito infestation, of energy as a useful and badly needed high infant mortality rate etc. It is said commodity while performing this treatment. that the pathogens emanating from human Further, anaerobic digestion of human was-te are responsible for nearly 80% waste also yields manure rich in nitrogen of diseases in India and the cost in terms which is safer to handle and reduces of medical treatment and lost production harmful pathogens, thus diminishing the on this account is around Rs. 450 crores chances of faeces-borne and related per annum.. For women, particularly in communicable diseases. the rural areas, the problem of facilities is particularly severe, as privacy The National Project on Biogas Deve-

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1 1 1 BACKGROUND PAPER 1 BIOGAS FROM HUMANWASTE 1 cases, environmental pollution and spread materials, aich as farm manure, of diseases. Dry conservancy system, , garbage and nightsoil, accom- 1 though not desirable considering the panied by the recovery of -methane aesthetic aspects, is likely to continue for fuel, has been an important in majority of villages and towns in India development in rural sanitation. 1 for the coming two or three decades, Some of the more important aspects as the water carriage system is very of recent advances are control expensive. In this paper an attempt has of temperature and introduction 1 been made to provide information about of mi.xing of digester contents. nightsoil digestion in laboratory scale Efficiency of some of the digestion units along with the data obtained on units decreased in the following 1 pilot plants. Some information has also order: been documented regarding removal 1 of parasites during nightsoil digestion. Thermophilic (seeded and agiated); Thermophilic (agitated only); Thermo- Treatment Melhods philic (seeded only); Thermophilic 1 (withou t agitation/seeding) Me sophi- i) The most common method in vogue lic (seeded and agitated); Me-~philic in India is burial in the ground either (seeded only). by itself or with town refuse. It 1 of-ten create fly and odour nuisance iv) Pillai and his associates at Bangalore along with contamination of ground have indicated that good activated 1 water by percolation and leaching sludge can be developed from night and may cause enteric diseases soil. treatment such as cholera, typhoid, dysentry, system will be an expensive proposi- 1 infectious hepatitis, helminthic tion under Indian situation. This diseases and ameobic dysentry. method of treatment is extensively 1 being used in Japan. ii) Chemical treatment requires treat- ment using lime and ferrous suiphate Gas composition was essentially 1 in a clarifloculator. The sludge the same under thermophilic and mesophi- is thickened, vacuum filtered and lic conditions. Heat required for thermo- sludge cake is burnt in a rotary philic is about 2.5 times that for mesophi- 1 kun. The separated liquid is neutrali- lic one. Moreover, the digestion time sed, diluted and treated in thickling and reactor size are about one half for filter or in an activated sludge the mesophilic one. 1-lowever the cost 1 process. The final effluents in the of construction of both types of reactors plants existing in Japan are reported for a certain volume of nighsoil is nearly to have neutral pH 60 mg/l BOD, the same because there is higher cost 1 150 mg/I suspended solids, coliforms of construction of digester in one type less than 300 MPN (most probable and the higher cost of heating element 1 number) and viable ascarisova less in the other. Thermophilic digestion is than 5 per 100 ml. This method recommended only when cheap surplus has limited application under Indian source of heet is available. Prolonged 1 context due to costs of collection use of thermophilic digestion proces~ and chemical treatment. may result in lysis of the micro-organisms and also results in the destruction of 1 iii) Extensive work has been done in pathogenic bacteria as well as parasitic the anaerobic digestion of cowdung ova fontained in the nightsoil. Ram Mohan and other organic materials. The Rao reported that thermophilic digestion anaerobic digestion of organic waste of nightsoil alone and of nightsoil and 1 1 10 1 BIOGAS FROM HUMAN WASTE cowdung mixture in the ratio of 2:1 resul- ted in a volatile solids reduction of 45% Approximate Composition (Dry Basis) and above, provided loa 3ding rates were Moisture, % 66-80 93-96 kept under 2.4 kg VS/m per day in both Solids 20-34 4-7 cases ~‘ith gas production of 0.45 and 0.35 m /kg of VS respectively. The speci- Composition of Solids fic resistances of dhe sludges wer~ fou2d to be 1.63 x 10 and 0.6 x 10 s g *Organic matter, % 88-97 65-85 for nightsoil alone and nightsoil w~th *Nitrogen (N), % 15-19 cowdung respectively. The specific resis- 5-7 tance of sludge u~ingnightsoi! at a loading *potassium (K),% 0.83-2.1 2.6-3.6 rate 2.8 Kg VS/m per day nearly doubled. *Carbon, % 40-55 11-17 CompQsting of nightsoi! along with *Calcium (Ca), % 2.9-3.6 3.3-4.3 town refuse has been and is still being *C/N ratio practised in many parts of the world. 5-10 0.6-1.1 But in many parts of India this kind of trealment is pursued in a very haphazard manner. This resuits in fly breeding, TABLE-2: Characteristics of Nightsoil odour nuisance and high incidence of used in Laboratory/Piot Plant helminthic infections. All the details Studies at NEERI, Nagpur. regarding decomposition has been documen- ted in a 5ionograph by World Health Parameters (Dry basis) Average Organi sation. Values pH 5.2-5.6 Characteristics of Night Soil Moisture % 86.7 Total Solids, % 13.3 The quality and composition of Volatile Solids, % 11.6 human faeces and urine are presented * Total Nitrogen (N) % 4.0 in Table 1. Table 2 describes the compo- * Total Phosphorus (o), % 1.53 si-tion of the nightsoil which w~s used * Potassium (K), % 1.08 in laboratory and pilot plant studies at NÈERI, Nagpur. BOD TESTED OVER 5 DAYS AT 20°C

Faeces is rich in organic materials - in gram per gram of total containing appreciable quantity of nitrogen solids 0.4467

and phosphorus. Data reported in Table - in gram per gram of volatile 2 indicate that on an average, nightsoil solids 0.5155 contained 13.3% total solids of which 8% were volatile solids. COD in g/g of total solids 1.0698 in g/g of volatile solids 1.2344 TABLE-!: Quality and Composition of Human Faeces and Urine BOD/COD/ratio 2.4 BOD:N:P 100:9:3.4 Approximate Quantity Faeces Urine * BOD/coD ~tio gives the proportion of biodegradable organic Water content in 135-270 1.0-1.3 matter to the total organlcs It enables-us to decide on whether all the nightsoil per gram Ii tre the wastes are artractive for biogas generatlon The higher the capita ratio the more the expected biogas Ed

Dry wt, per capita 35-70 50-70 About 44.7% of total solids of 51.6% gram gram volatile Solids in nightsoil are easily

11 1 BIOGAS FROM HUMAN WASTE 1

this loading, it is possible to decom- Addition of nightsoil to cowdung 1 pose more than 50% of volatile can stimulate biogas production. When matter wit~i gas production greater cowdung and nightsoil were added in than 0.5 m per kg of vola~ile solids equal proportion in 3volume,/kg of thevolatilegas producsolid- 1 fed (i.e. 0.92 to 1.12 m per kg tion was 0.35 m of volatile solid decomposed). This added. The correspontling gas production gas would have a methane content per kg VS of nightsoil and per kg VS of 60-65%. added. The corresponding gas production 1 per kg VS of nightsoil and per kg VS During the studies, it was observed cowdung - ~ach digested ~ separately - 1 that the slurry in the digester separa- were 0.49 m and 0.13 m respectively. ted out into two distinct Iayers The authors also observed that cow dung has a potential to suppress ammonia - sludge at the bottom and super- 1 natant at the top. Up to 6.22 per toxicity since the quantity of ammonia- cent solid concentration in the cal nitroger~ released into the slurry feed, the digested sludge dried was low in the feed mixtures as compared 1 quickly on a sandbad. The dewatera- to night soil alone. bility of the sludge deteriorated with increasing solid concentration Removal of Pathogens 1 in the feed. Dried cake was black in colour and had no smell. Digested Shanta’2 carried out laboratory 1 nightsoil slurry had an average studies to determine the extent of removal 2.8 to 4.8% of N, 2.2 to 4.0% of of helminth parasites removals during Phosphorus (P 05) and 0.5-1.6% nightsoil digestion. at 37°C and results 1 are presented in Table 5. of Potash (K2O~on dry basis. Thus the manurial value of night soil Ascaris eggs survive for longer 1 is retained in the digested slurry. periods than hooI~worms.Itis also observed that the sludge and supernatant from Shanta’’ carried out laboratory digester still contain viable eggs. 1 studies at 37°Cusing various propositions of nightsoil and cowdung and the results are presented in Table 4. 1 Table -4: Effect of Addition of Cow Dung in Night Soil 1 Gas Production Nightsoil Cow Du~i& m3/Kg/VS % % Volatile mat-ter Volatile mat-ter 1 Added (VSa) Destroyed (VSr) 1 0 100 0.158 0.740 25 75 0.210 0.860 50 50 0.350 0.920 1 75 25 0.400 0.920 100 0 0.500 1.090 1

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14 BIOGAS FROM HUMAN WASTE

Table - 5: Percent Reduction of Helminth Ova in Laboratory Night Soil Digester

Load- Deten- PH Influent Effluent ing tion No4J~’~Litre No.Ova/Litre Reduction rate time Ascaris Hookworm Ascaris Hookworm Ascaris Hookworm Kg./ d VS.d

2.21 20 7.50 4000 58200 2080 21360 48.0 63.2

1.78 25 7.60 114000 - 18200 38324 1639 66.5 90.6

1.45 30 7.65 94110 21820 28248 1528 70.0 93.0

NEER! also conducted extensive 18 m3 and 29 m3 capacity nightsoil diges- studies on pilot nightsoil digesters at ters are reported in Table 6 and 7. Removal Central prison, Nagpur to demonstrate of helminthic parasites from 18 m3 pilot the techniques of total recycle of human plant is presented in Table 8. Details wastes. The digesters were similar to about the gas production, composition KVIC gas plants in all respec-ts except of gas, calorific value, manurial value for the addition of a manually operated etc. obtained from the pilot plants are homogeniser to bring nightsoil into a reported in Table 9. suspension before it is fed to the digester. Nightsoil was homogenised into a slurry The study was carried Out at an average of 6 to 8% total solids. Once or twice digester temperature of 28°C while the in a week, the digested sludge from the ambient temperature varied between nightsoil digester was withdrawn into 13°Cand 33°C. a sludge drying bed. The resuits for a

Table -6: Experimental Re9ilts obtained on 18 m~Capacity Pilot Plant.

Parameters S E T S 1 II III IV

Average loading Kg 2.02 1.55 1.73 3.08 of volati.~esolid added/m /day pH 7.2-7.8 7.1-7.5 7.4-7.9 7.0-7.6

Alkalinity, mg/litre 10,294 9,000 12,000 10,000

Total solids, % 6.50 6.10 6.10 6.45

Total valitile Soil % 5.31 4.92 4.86 5.89

Volatile acids, mg/litre 125.1 175.7 130 4246

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- -~ -~ 1 BIOGAS FROM HUMAN WASTE 1 Total ammonia-N, mg/litre 2100 1875.8 1912 1302

CST 1155.3 646.3 493 1302 1 52.7 48.8 50.5 57.4 VS reduction, % 1 0.437 0.430 Gas production, m3/kg 0.367 0.245 VSa (volatile solid added) 1

It was observed that there was same with in~reased loading rates up-to 1 no clearcut separation of sludge and 3.56 kg/VS/m /day but the dewatera- supernatant and only slurry could be bility of the slurry decreased appr~ciably.* discharged.* About 0.076 kg cake/capita/ This is an important point because the 1 day with 50% mixture was produced. area for sludge drying will increase with It was also noticed that the performance increased loading rates. of digester remained by and large the 1 1 Table - 7: Experimental Re~iltsobtained on 29 Capacity Pilot Plant. 1 SETS Parameters II Average loading, Kg VS/m3/day 2.00 1.16 1 pH 7.1-7.6 7.2-7.8

Alkalinity, mg/litre 8500 11000 Total Solids, % 4.5 5.9 1 Total Volatile Solids, % 3.5 4.6 1 Volatile acids, mg/litre 184 743 Total ammonia as N, mg/litre 1701 2162 1 CST 2761 1268 1 Volatile solid reduction, % 52 54

Gas production, m3/Kg of VSa 0.289 0.655 1 (Volatile solid added) 1

* These contradicted Trivedis observacions given earlier Ed 1 1 16 1 BIOGAS FROM HUMAN WASTE

Table - 8: Removal of Helminthic Ova in 1* m~Capacity Digester

Parameters 3 Per Cent Removal Loading Kg/m a Hook Worm Ascaris

1.99 66.0 ± 23.10 37.0 ± 22.61

1.60 70.0 ± 12.11 52.1 ± 16.51

1.79 65.3 ± 23.64 35.3 ± 22.7

Table - 9: Other Re~~ItsConcerning Gas Production Manurial Value, etc.

Parameters Value

3 Gas production/capacity/day 0.025 m

Methane, % 60.65

Carbon-di-, % 30-35

Hydrogen Suiphide, % 0.05-0.10

Fuel Value, K cal/m3 5600-6500 Quantity of sludge produced 0.71 Litres wet/capita per day with 5% total solids.

Manurial value of sludge

-. Nitrogen, % 3.25

- Phosphorous, % 1.00

- Potassium, % 0.83

Practical Application community, several small units will have to be built at different locations, if Based on the laboratory and plant mechanical units have to be kept low. studies, it is possible to design nightsoil This may also facilitate easy handling digesters for different population groups and transportation of nightsoil from respec- up to 2000 persons. For higher population, tive localities to the treatment site. data can be adopted for designing but Community nightsoil digesters have been instead of one digester for the entire designed and oplerated successtully by

17

- - ~ 1 BIOGAS FROM HUMAN WASTE 1 13 Badrinath, et at a detention period of 25 Sulabh International. al’4 have given elsewhere the specific days. design details of nightsoils diesters, which 1 would be very useful in this connection. 3. Nightsoil addition can enhance the production of biogas in cowdung Nightsoil collection and disposl digestion. 1 will continue for several more decades in our country and it is necessary to 4. Data c~pcerning tjle performance 1 consider total recycling of nightsoil. of 18 m and 29 m nightsoil diges- It consists of digestion of nightsoil and ters have been reported including recovery of the biogas generated. The the manurial value of the digested 1 digested slurry will be filtered on sludge sludge. drying beds and the dried sludge can be used as manure. The filtrate from 5. Total recyclying scheme for nightsoil 1 drying beds will be treated in an oxidation has also been indicated for future pond followed by polishing pond* to reduce use for large population areas. BOD and other pollutants and also for 1 removal of bacterial and helminthic patho- ACKNOWLEDGEMENT gens. It. is possible to harvest fish from these ponds provided the effluent is The authors are thankful to Director, 1 diluted with fresh water. NEER!, Nagpur for his permission to prepare and publish this piece of rearch 1 CONCLUSIONS: work.

1. Various methods that are being REFERENCE 1 adopted for treatment and disposal of nightsoil have been listed. 1. Horassawa, 1, et al - Biological Studies of Nightsoil Treatment- 1 2. Laboratory studies carried Out at Publication of the Kubota Instt. NEER! on nightsoil digestion revealed of Sanitary Engg., Isaka, 1962. the following: 1

2. Acharya, C.N. - Preparation of a) per capital contribution of Fuel Gas and Manure by Anaerobic total solids and volatile solids Fermentation of ORGANIC Nutrients 1 is 64.7 g and 56.3 g per day. ICAR Res. series No. 15, I~dian Council of Agril. Research, NEW b) For design purposes, total DELHI, 1958. 1 solids concentration in the feed, detention time and loading 3. Henze, M. et al (Editor)- Fixed 1 rates and important. Film Fixed Bed Reactor, Symposium Volume, Denmark, 1983. c) Digesters become non-opera- 1 tive if the free ammonia concen— 4. Ram Mohan Rao, 1.- Laboratory tration exceeds 275 mg/litre. Studies on Ther mo-Philic Dige stion

of Night Soil - M.Tech. Thesis sub- 1 d) Ascaris and helminthic parasites mitted to Univ. of Nagpur, 1970. are removed to the extent

of 67% and 91% respectively 5. Gotaas, H.B. - Composition - Sanitary 1 1 * “Polishing Pond” is meant for ‘polishing up” the filtrate from the sludge-drying beds, i e for tmproving its quality further Ed 1 18 1 BIOGAS FROM HUMAN W~SIE

Disposal and Reclamation of Organic on Night Soil and other Organic Wastes, WHO Monograph No. 31, Wastes Ph.D. Thesis, Nagpur Univér- Geneva, 1956. sity, 1973.

6. Mudri, S.S. - Some Observations 11. Shanta, S. and Mohan Rao, GJ-.

on Anaerobic Digestion of Night - Effect of Mixing Cow Dung and

Soil - 3. Envn. Health (India), 2~ Night Soil in Anaerobic Digestion 133, 1967. - NEERI !nternal Report, 1970.

7. NEER!, !nternal Report, 1976. 12. Shanta, C. - Survival of Helminthic Ova during Anaerobic Digestion 8. Despande, C.V., Shanta, S. -Effect of Night Soil, NEER!, !nternal Report, of Low Solids Concentration on 1970.

Anaerobic Digestion - Submitted to 3. Asian Environment, 1985. 13. Night Soil Digestion Plant for Sulabh International NEER!, !nternal Report, 1982. 9. NEER!, Internal Report, 1974.

14. Badrinath, S.D., Gadkari, S.K. - 10. Trivedi, R.C. - Studies ~,p the Ammo- Design of Community Biogas Plant

nia Nitrogen Behaviour in Anaerobic - Salient Features - JIPHE, Vol. System with reference to Digestion 1, 1982.

19 1 SOCLAL ASPECTS

1 1 NIGHTSOIL BASED BIOGAS PLANT Its roll in social equality and community benefits and the problem of its social acceptance Smt. SavigriMadan*

1 Abstract

Thirtyashealth,a ~Bhangiwomen’sfourMukti”welfare,yearsmeasureback,achievingnightsoil(upliftmentsuccessbasedofin afforestation,scavengers).biogas plantsButimprovementwereits constructedimpçrtanceof soilessentiallyforfertility,public production of better quality of crops and an aesthetically satisfying environment is immense. The sources of inhibitions that impede the spread of biogas plants are discussed. The primacy of political will and the importance of highly motivated voluntary agencies are emphasised. Iniroduc tion

In our country, Late Appasaheb the methods and implements for the disposal of nightsoil have to be improved. 1 Patwardhan pioneered the RoJe of nightsoil based biogas plants of nightsoil based biogas plants more in “Bhangi Mukti” asthana thirtysocial yearsbenefitbackprogramme(sirx~e1953),for emancimainly- I pation and uplif t of ~avengers (Bhangi Appasaheb Pathwardhan had fully realized the significant role that nightsoil ofMukti).‘BhangiLater,Muktiin his Samiti’capacity (whichas chairmanwas I constituted in 1957) of Gandhi Smarak based biogas plant can play as a source of , better health and energy. I Nidhi,help (subsidy)he advocatedfromandNidhi’sarrangedfundsfinancialfor However, his stress was on the social the construction of biogas plants. Conse- benefitts (Bhangi Mukti) likely to be quently, Maharashtra Gandhi Smarak derived from the plants. The biogas plant I Nidhi continued the work of construction design developed by him was a water of nightsoil based biogas plants as a jacketed floating dome type plant modified part of its ‘Bhangi Mukti Yojana’. from ‘Gramlaxmi’ design developed by Sri Ja~hai Patel. Further, he lnsisted Ideology of ‘Bhaogi Mukti Yojana’ that it ~ould be onsite disposal plant to which latrines were directly connected, Late Appasaheb Patwardhan passion- SO that not even mechanical carriage of nightsoil was not involved. This plant could be very easily maintained by any I committedelseately tofeitdo (i)towardsour thatown humanity.todirtyforceworksomeTheis a scaonesin- family without some one else’s help. The scavenger then thus treed from dirty work, could be rehabilitated by learning vengerundignified,who doeslowly thisandjobuntouchableis treated asin I social structure. This can be changed other ~

t Maharashtra Gandhi Smarak Nldhi, Pune

23 1 BIOGAS FROM HUMAN WASTE 1 should be based primarily in scavenger’s in their own farm or seil it. colonies, to be maintained and used by them is a very distorted view of the Benefits for the Community is~ie. In fact it would be a new device to perpetuate the social injustice meted Latrine-connected biogas plants 1 out to the scavenger community. In Maha- will yield other benefits rashtra several such ‘onsite’ disposal nightsoil based biogas plants are functioning i) Cutting the trees for firewood will in individual households and institutions. be reduced in proportion to the 1 They are maintained by the families available biogas~ or institutions ihemselves. 1 ii) !ncidence of communicable diseases Thus, by adopting a suitable design will be reduced due to lesser pollu- and methodology fort implementation, tion of water sources and lesser 1 the nightsoil based biogas plant can plan faecal contamination of food through a very significant rofe in ‘Antyodaya’ flies and insects. 1 and social equality programmes. iii) Ailments in the populatior would be reduced. Wo men’s WeLfare 1 iv) Crops would be healthier if open In rural setup women face a consi- defecation in the fields is reduced. derable problem as regards attending 1 to nature’s cail. Nightsoil based biogas v) Availability of organic manure of plant placed in one’s own family or amongst high quality would be beneficial a group of houses will ease this problem. for the crops. 1 It would be feasible even if the household does not possess any cattie. The latrine Problems in Social Acceptance could serve the purpose. 1-lowever, if 1 at a little extra cost nightsoil biogas It can be said without any hesita- plant could be constructed, it would tion triat the nightsoil based .biogas plants 1 augment their fuel supply and would offer benefits in terms of social, econo- reduce their work of collecting firewoo4. mic, jiealth and environmental improve- Time saved from this work could be ments. Yet, the programme of constructing 1 used for recreation, care of children nightsoil biogas plants may not be very or for earning some extra income for easy to implement. Suitable technology family by stitching etc. Further, it will is not much of a problem. Necessary 1 partially improve their lot in the kitchen. financial input will also not be very diff i- cult. The major hurdie will be a social Benefit to family acceptance of these plants. Inhibition 1 to. use biogas and slurry from nightsoil There would be multiple benefits based biogas plants is noticed on several for the family. The time, which the family grounds. Efforts to deal with this inhibi- 1 members spend in going to far away tion effectively will have to be made fields for defecation, will be saved. very vigorously. Some important factors The home airroundings will be clean, responsible for this inhibition could• be 1 pleasan t and ae sthetically satisfying. identified. In addition, the generated biogas will 1 reduçte the expenditure on fuel. Further, 1. Ignorance about the nature of biogas manure of a very good quality will be leads to a misconceived feeling available, which the family can use either that these end-products are dirty 1

24 1 1 BIOGAS FROM HUMAN WASTE

and unhygienic. be an asset in promoting this work. However, it will yield better results 2. A wrong notion prevails that the if the Government identifies such nightsoil based biogas plant will institutions, encourages them and make their surroundings unclean heips them financially for this task. and foul smèlling. It would be worth remembering that the initial construction and 3. A feeling exists that the grains promotion of nightsoil based biogas and vegetables grown in the farm plant was a totally voluntary and where slurry is used as a fertilizer, mnspired effort of Late Appasaheb will not be clean and wholesome. Patwardhan. Later it was continued by Maharashtra Gandhi Smarak 4. A doubt about religious sanctity Nidhi, which unfortunâtely got creeps in one’s mmd. One feels very limited back-up from elsewhere. that it is not right to use gas and food obtained from dirt, for religious ii) The Government already has an purposes. infrastructure for rural development. This machinery could be motivated 5. Possibility of ridicule from neighbours for promotion of nightsoil based and relatives weighs heavily on biogas plant. Voluntary agencies the mmd of the user. can act as resource agencies for the orientation of these personnel. 6. A fear of possibie non-acceptance of eatables from the user’s home iii) Political wilk This is probably the by the villagers become a formidable most important factor. The decision de terrent. for promoting nightsoil based plants through out the country will have Many more reasons could be enumera- to be a decision of the represen- ted. To counter these deterrents, educa- tatives of the people. With this tional efforts will be required for tackling support, it will be easy to promote

these problems. - nightsoil based biogas plant as one of the tools for social uplif t. Improving Social Acceptance Coriclusion It is not proposed to deal with detai- led measures for promotion in this paper, It is feit that the social uplif t. aspect It would be adequate to put forth a general of nightsoil based biogas plant are very perspec tive. significant. With the political will and efforts of voluntary agencies and govern- i) Role of Voluntary Agencies mental infrastructure, nightsoil gas plant will positively enrich rural social and l-Iighly niotivated voluntary agencies cultural fabric. possessing missionary zeal will

25 1 1 SOCIAL ASPECTS OF 1 NIGHTSOIL BIOGAS PLANTS IshwarbhaiPatel 1 Ah~tract 1 The paper gives inspiring instances of nightsoil based biogas-cum-manure production in Gujarat that shine through the mist of ignorant preju.dice. These experiences should 1 help overcome the pessimism that it will be long before nightsoil based biogas-cum-fer- tiliser plant becomes socially acceptable. Defects in biogas construction and planning, which came to the author’s notice during a survey of 120 samples, are listed. Constructive 1 suggestions for improving the efficiency of bio-degradation, increasing the temperature regimen of biogas plants and for amendment of govemmental procedures are given. 1

- Ed. Iniroduc tion ties’ connections of laWines to biogas 1 ~lants are rather recent. In village Khoraj, There are 46087 biogas plants, ir~ Gandhinagar District (Gujarat), so me Gujarat; 6467 latrines are connected 10 latrines have been connected to the 1 to biogas plants.The first biogas plant biogas plants, but the use become effec- in Gujarat with public latrines connected tive after 15-18 months of construction. to it was constructed at Safai Vidyalaya, This was made possible by mass education 1 Vyara, Gujarat in 1958 on private property. by a lOday workshop which incorporated The biogas thus produced was used to reiigious, scientific and educatiönal cook food for 15 employees and also basis of biogas plants. At Nadiad, Gujarat, 1 for illumination. The digested sludge 16 latrines ‘used by 400 girl students was carried away by the municipal authori- had been connected to biogas plants. ties. This success Story was repeated They did not accept the tea and snacks 1 in the post-basic schools and hostels cooked with biogas this indicated the in Surat District. Biogas Plant Technician deep-roo ted prejudice. So me progre ssive 1 Training courses of 3 months’ duration farmers with scientific approach connec- were conducted. Yet, our people are ted latrines to their biogas plants in yet to accept the use of biogas plants 1958. But even today a stigma is attached 1 with laWines connected. As per Manu- to it so that food cooked with biogas smriti, it is stated that latrine should cannot be an offering to God. be located 400 steps away as defecation 1 is considered dirty. In the conventional In Vahelal, Ahmedabad District, communities orthodox people visit latrines a farmer has constructed a flat-roofed by putting on separate clothing. The biogas plant in his floor area with the 1 Mohenjodaro excavations have revealed latrine connected to it. The cattle dung, the provisions of and drainage too, is fed to it. The digested slurry but not of iatrines, implying thereby is collected by the women in the house 1 the prevalence of and dumped in the pit. Such which corroborates belief in Manusmruti illustrations are useful in shaking social statements. inertia and countering prejudices. It 1 has been observed that the Advisi agri- The rural as well as urban communi- cultural daily wage earners do not handle 1 • Principal, Safai Vidyalaya, Harijan Ashram, Ahmedabad 1 26 1 BIOGAS FROM HUMAN WASTE

Ihe digested slurry; in them the feeling their eyes. It has proved to be a blessing is well entrenched that only the scavanging to them as the womenfolk can now have community can do such jobs. Such trends privacy during the daytime without are based on “religious beliefs”. having to cover long distances. It leads to better health because poor sanitation A progressive farmer of Ramp and unprotected water are responsible (Ahmedabad) constructed two latrines for 80% of prevalent diseases which in his premises, one for own family cause a loss of 73 million mandays. and other for the public who may not It saves an equivalent of Rs.500/- in be having such facility. He invites people terms of production of gas and . to use the public latrine. Some 40 users avail themselves of it. The owner runs Sulabh International has started his family kitchen from the biogas produce community biogas plants with latrines therefrom. In the Chetanawadi area connected to these. It is necessary to of Mehsana (Gujarat), a biogas plant, propagate the concept that waste is fed from 6 latrines serving 12 tenants wealth when it is recycled. The implemen- is in operation. The tenants get cooking tatmon becomes successful when the gas at Rs. 35/- per month. The outgoing maintenance and cleaning is done by slurry is used as organic manure to the owner. It is observed that generally, grow vegetables. It is an excellent example the prosperous farmers avail themselves of low-cost sanitation wmth recycling of this scheme. It has not yet percolated of wastes. Another biogas plant is in to the strata of landless labourers. operation at the Pathey Hotel at Krishna Nagar on the National Highway which Ideally, the theory and practice prov’des easing facilities for passengers, go hand in hand but in reality, there drivers and conductors. The b~ogas is is always a gap. It is necessary to bridge utilised in the hotel. In a decent large this gap. The following observations hotel Ahmedabad in a rural environment, are based on a survey of some 120 samples. Jivestock wastes and garbage are fed to the digester and the biogas from 1. The field results hardly approach it is used in the kitchen. The digested, .50% of the figures claimed by drained, dried and parcelled out slud&e scientific bodies. cakes are packed in 2 kg polythene bags and sold at Rs. 5/- each for the 2. The organising agency does not, city’s mndividual kitchen gardens. Such in general, posses adequate know- experiences should help demolish the ledge about biogas plants. The social stigma attached to connection available information does not of nightsoil to biogas plants. reach the users.

Financial Subsidy for Latrine connected 3. The proportion of excreta and Biogas Plants water is 1:2 litres per use. This slows down biochemical reactions The Government of Gujarat pays and reduces the liberation of bio- a aibsidy of Rs. 300/- to any biogas gas. plant which admit wastes from latrine. This scheme initiated by the Rural Deve- 4. Normally one large sludge drying lopment Department had a positive bed is provided but it is necessary impact and gathered momentum, thanks to have 4-5 small ones. to the co-operation of educational and other institutions. lt saved rural women 5. Distances of biogas carrying pipes from smoke nuisance which affected were found to be very long. It

2~ 1 BIOGAS FROM HUMAN WASTE 1 should not exceed 20 m. Suggestions and Recommendation~

6. Biogas plant should not be under Nightsoil has been looked upon any shade or shadow at any time wmth repugnance. Because of maladies in the day. Only 70% plants were associated with nightsoil, the operational 1 found to be free from the shadow and maintenance personal have been walls and only 10% plants were looked upon wmth disdain. Nightsoil, found to be away from Wees. if misused or mismanaged, is hazardous. 1 1f managed scientifically and carefully, 7. The priority of users was found it yields several benefits. Some emperical to be in the following order: cooking, suggestions from scientifmc and social 1 mechanical gadgets, and manure. standpoints are made below. About 98% of biogas plants were seen to be used for cooking purposes 1. The size of gas dome may be reduced 1 only. to get more pressure and effective anerobic biogradation. 1 8. For maintenance of gas pressure for flow, the slurry must be fed 2. Non-corrosive HDPE (high density twice a day. In 95% of the biogas polyethylene) or fibre-reinforced 1 plants, feeding of slurry was done containers are available only once a day. as gas holders. These may be painted black for absorption of solar rays. 1 9. The proliferation of biogas plants is of national importance. It has 3. Attempts are needed to use local been observed that procedures and inexpensive materials for cons- for obtaining Sanchai and Subsidy truction of biogas plants. are arduous and timeconsuming 4. Intensive and effective training as was feIt by 75% of people under programme coupled with simplified 1 study. procedures for quick processing of applications along with their 10. The organisers were found to be relevant publicity would go a long 1 running after target of numbers, way in mass propagation of plants forgetting the users and the nece- for decentralised harnessing of 1 ssary oprational guidance is diffmcult renewable resources of great national to get. i mpor tance. 1 1 1 1 1 1 1 28 1 ‘uig ij~~#,iq~em4ffM ~iu

S~fiyrt ~* t I~Siqï m3fllJ ~ 31S ~fi!3T~9W ~ftdIR*9~t-~ ~ ~ sûç~ii~-it~t ~f~9i~hi 4 ~t ~w~iq~~ ~t~m ar~i~ftm ~ kt~~9JË1W* wmqft~ig’ ~fl~S~*ft ~TtI9at~1Tfl~RT, ~ f~i amv~q~ffi~~i

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R~*I ~ ~1119Tt ~~r#~q 5OO~t~aWit~T q~TSi fl tm ~m, twi~uaft,~aumaiïft 4 ~i~nï~ ~ t_~~t auta~ti~9t9~~ ~t 1ik11)(uI ~Tt~9~ a~~3qi~)Tftç3-q~~3i~r~j* ~w:Fw3*T *1

2S 3 çjc~4~c~ ar@i ~ afirnr~aï~r ~1T~IT,~é a~t~n’m~r4 a~f~~# %~iiw&Otam~ ~~1~4~Ta1aft4 4 U3TW ~~ÎI91

29

L-:~~ ~.; - 1 1 SOCIAL ASPECTS OF THE NIGHTSOIL BIOGAS PLANT PROGRAMME 1 THROUGH CASE STUDIES 1 KrishnaMahapatra 1 This paper presents the fruits The Puri, Varanasi and Midnapur of certain case studies where community plants are entirely for Harijan communi- biogas plants were constructed without ties.The Masudpur plant is a part of 1 the community’s participation in the a demonstration project of Khadi Gramod- formulation of schemes. yog, and the beneficiary group which has to pay for the gas aipply for cooking 1 The social aspects are the most purposes, is a mixed group in the neigh- significant aspects of a technology-inten- bouring village complex comprising of 1 sive programme and may decide the different caste and class and awareness latter’s fate in terms of aiccess and backgrounds. failure. 1 While the Midnapur plant was In the nightsoil-based biogas progra- closed down alter a few months of mme, these.aspects have been of greater functioning and was thus a total failure, 1 significance due to the sensitivity of the other three plants are in varmous the issue in the Indian socio-cultural stages of functioning under a wde range context. of constraints which range from purely 1 social to the technical. Very broadly speaking, such techno- logy-intensive programmes seem to have The Puri and Midnapur plants were 1 three main aspects: fed by nightsoil carried from dry latrines to the plants through the municipality 1. The te-chnical-including the skill collection system. involved, the resources etc. The Beriban (Varanasi), Masudpur 1 2. The social-inciuding the beneficiary (Haryana) plants were attached to latrines group attitude, the use concept which were specially constructed to e tc. be used by men, women and children 1 of the villages. 3. The organisational aspects - including the maintenance, the running of In all these cases the gas was 1 the programme etc. chief ly for cooking purpose except at Beriban where the use was to be for This paper through case studies lighting which was a greater need for 1 of nightsoil based community biogas the people. plan-ts at Puri, Varanasi, Masudpur and Midnapur tries to illustrate the signifi- From the study of the 4 community 1 cant role of social aspects in the positive biogas plants significant aspects which implementation and working of the pro- come to light are~ gramme and seeks to give some sugges- tions. 1. The Puri programme was started 1 • Social Scientist, AFPRO, New Delhi 1 30 1 BIOGAS FROM HUMAN WASTE

without the people’ s participation, areas but the use of latrines was but still was a relative success not a practice here. The poor as the economic benefits overruled mamntenance of laWines due to the constraints of ethos and values shortage of water added to the and the feeling of discrimmnation propensity to avoid of the laWines. as lhey were Harijans. With several construction works going on for multi-storeyed buildings 2. The Beriban programme at Varanasi around the village the villagers was an impractical idea under were gradually fmnding a shortage the given conditions and therefore of open grounds, but the !aying non-functional. The most important down of sewage system in the constraint was the shortage of village had given them hope of water. Next was the ethos of women having their own latrines in their who must not be seen going for homes and til! such time they natures’ cali, with cans in hand preferred to “somehow manage”

- as it was something to be shy rather than go to the “closed cooped- of, in view of the man-woman up filthy latrine.” relationship. The study of the four cases quite 3. Masudpur programme was different clearly establish the need to ensure as the villagers using the gas for people’s participation at all levels of cooking did not have the feeling planning, implementation and management. of abhorrence seen in the other

31

-~ -; -- - 1 1 BIOGAS PLA.NTS BASED ONNIGHTSOIL

Arnulya Chakraborty 1 Al~2ruct 1 The thirty latrine-connected AFPRO-design-based family-size biogas plants construc- ted in Contûi sub-division (Midnapore district, West Bengal) have been operating without much trouble so far as gas generation is concerned. In rural areas, the movement for low-cost 1 latrine and smokeless chullah has caught on. Progress in the progra mme for nightsoil- plus-other animal-waste based biogas plants depends on innovations in (0 low-cost design; (ii) the technology of using water hyacinth and varieties of foliage as inputs along with 1 nightsoit and cattiedung; and (iii) the finding of uses for the siurry as fish meal and the like. The paper posits a few other questions requiring research based scientific advice. 1 The disappearance of bushes and jungles has greatly reduced the scope for open-air defecation. The resulting threat to women’s privacy has created a strong impulse for 1 domestic latrines. The grave shortage of fuelwood and the need for keeping the ponds clean as a source of water for cooking purposes have created a new awareness for night- soil-based biogas plants. People have come to feel that the alternative is helpless depen- 1 dence on tubewells that often go Out of repuir and the pollution of tanks by nightsoil washed over from the roadside by rainwater. 1 -Ed. Iniroduc tion scrapings of carcass of dead animals 1 as inputs for quick generation of energy. The Lok Shiksha Parishad, Narendra- The plant owners are reluctant to use pik evolved a system of latrine based such material. We. too, have not found 1 on a pan attached with a U-pipe and any literature which aiggests that such without any . The nightsoil material can be fed into biogas plants. is discharged into the digester of the Progress/innovation is necessary 1 biogas plant (1.3 or 5 cum as may be in the following respect~ the case) by a pipe, In every case the latrine-connec ted fixed-dome plant i) Low-cost design for domestic latrine- 1 is fitted with an inlet chamber for feeding connected biogas plant digester. cowdung and outlet chamber for discharge of the slurry according to the AFPRO ii) The utility of fresh slurry as fish design. In this way nearly 30 biogas meal. It has to be well established. plants of family size (2 or 3 cum), cons- tructed during 1985 in f ive villages iii) The proportion of materials like in Contai Sub-division are found to be water hyacmnth and similar varieties operating without much irouble so far of foliage in relation to cow dung 1 as gas generation is concerned. or nightsoil for ensuring gas and light at the rated capacity. In some cases where mixed feeding 1 system was introduced, the DIC staff Besides, scientific advice is needed of the district suggested the use of on: 1 * RK Mission Lok Shiksha Parishad, Narendrapur, 24 Parganas, West Bengal 1 32 1 BIOGAS FROM HUMAN WASTE i) the pros and cons of substitution Bengal) are now responding very enthusias- of the inlet chamber steps by a tically to ôur education-cu m-mo tivation pipe as in the KVIC model. (This camps for propagating biogas plants is generally advocated by DIC). with a stress on nightsoil. We have tried to examine the factors behind such ii) the advisability of otherwise of enthusiasm. 1 may cite here a very impor- putting animal carcass of dead tant factor behind aich motivation. animal s. It is the crisis in the traditional open-air Inlegration with Development Programme toilet system. In one education camp held in a village in North 24-Parganas It is observed that the move for district in 3uly 1986 the heads of the introducing smokeless chullah and low- Muslim as well as scheduled caste families cost latrine has made some headway argued that low-cost latrmnes are now in the rural areas.The programme for e ssentially required for womenfolk. low-cost nightsoil biogas plants should The gradual disappearance of the village now be emphasised. In fact, the response forestry, bushes and jungles makes it of the villagers wherever we went and extremely difficult for the women in propagated the utility of the biogas particular to go out to the traditional plants has been beyond our expectation. open-air latrine. Increasing population and extension of housing are also creating Here again, the problem is that problems in this matter. a large number of enthuiasts for biogas plants in the villages are without any In a similar education camp conduc- cattle or poultry or piggery. Now, domes- ted by us in the South 24-Parganas tic biogas plant (even 1 cum size) cannot (near the Sundarbans) very recently generate gas only by nightsoil from people showed eagerness for protecting the smail-size and single-family systems, the village tanks from roadside by heavy because it appears that the regular ram water. These tanks are the main use of connected laWine by 35 to 40 source of water lor cooking and washing. persons will produce gas from the plant Tubewelis are too few in number and considered ~jfficient for only 5 to 6 once a tubewell goes out of order, repair rnembers. In aich cases our advice has becomes a problem for the Panchayat been to collect cowdung from outside Samity. Therefore, a latrine is now-a- or set up poultry farms or have goat days a common demand in these areas. farm or piggery so that the additional Wnen they were told that a digester feeding material may come from their can produce cooking fuel and sorne light own household. These are, however, in the evening, they were all for it. good as advice but cannot be practised A public sector Bank has assured that by villagers in general. The matter, proposals sponsored by our institution however, requires some analytical study will be financed by them. by the experts so that some concrete aiggestions might be offered to the These instances show that nightsoil villagers who are willing to have biogas based biogas plants have now caught plant fitted to latrines but have no the imagination of the people. Our conten- cattie of their own. tion is that the experts in the AFPRO, CORT, CART and the Non-conventional From the Viewpoint of Domestic and Energy Departmènt of the Government Sociai Samtation have now to find Out how gas generation from nightsoil based digesters can be The ordinary famiies in the villages augmented in an easy process practicable in different districts of our State (West for the villagers. The programme for

33 1 BIOGAS FROM HUMAN WASTE 1 energy and sanitation is intimately connec- use the community laWines, the optimum ted with the movement for pollutmon-free aas generated from the plant can serve environmen t. only about 30 of them, that is one member 1 per family. So, we cannot proceed with Let us also consider the issue of any such project unless additional feeding community gas plants. Proposals from is available. That can be arranged from 1 about half-a-doze areas have been made outside but a cost will be mnvolved both to us for nightsoml-based community for the material and management.We plants in village areas where a particular propose to utilise water hyacinth that 1 vocational group of families reside in is abundant in the marshy land near a cluster.In one such area, there are by. But It may not be a permanent 30 potters families, their total popula- solution. What is needed is a break-through 1 tion being about 220 (adults and minors byR&D. taken together). Even if all of them 1 1 1 1 1 1 1 1 1 1 1 1 1 1

34 1 1 HEALTH ASPECTS

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NIGHTSOIL BIOGAS PLANTS Health Aspects

S.R Kshirsagar*

Abstract

This peper gives the waming that nightsoil-based biogas plants which are being propagated as a health protection and energy conservcition measure many themselves turn out to be the source of dissemination of diseases unless utmost care is taken at all stages. 1f the nightsoil is to be manually collected from elsewhere for feeding into the digester, the scavengers come into direct contact with pathogens. It is possible for the pathogens to survive in large nuinbers in the digester and pass over to the effluent. Anaerobic cligestion over merely 30-35 days’ detention time is unhelpful for pathogen destructmon. Even the drying of effluents removed after this insufficient detention time does not help in making the manure innocuous. There are great hazards if the crops grown with such manure are eaten raw. The use of sludge on croplands or in fish farms contaminate food articles widely. In the same manner as labourers are sewage-fed farms suffer from higher incidence of infections of helminthic and intestinal pathogens, the workers on sludge-fed farms, too, are likely to be victims. The conclu.sion that flow from the above observations is that a longer retention time in the digester (HRT) is necessary since the optimal conditions in terms of tempera- ture, pH and moisture content are unavailable in field conditions. Sun drying on open sandbeds for 10-20 days has been recommended. Aerobic composting of the ~slurry with agricultural wastes, which at its peak period raises the temperature to over 60°C, has been recommended. Ed. INTRODUCTION

Biogas generation through anaerobic of human excremental matter for biogas decomposition of organic matter is ?rot- production, attention must be paid to new to our country. It has however presen- the health aspects involved in its procure- tly assumed greater importance and signi- ment and use in biögas Ünits and also ficance in the context of energy crisis in the disposal/use of the effluent because and the need for development of renewable of the possible presence of pathogenic sources of energy. organisms. Table No.1 gives common types of pathogenic organisms present Healiti Aspects in human excremental matter and urine. Although a variety of organic mater- Handling of raw human excreta, ials such as cattle dung, water hyacinth, even as feedstock for production of biogas, agricultural wastes, can be used as a obviously resuits in a great occupational feedstock for production of biogas, the hazard. The system of collection and use of human excreta is advantageous conveyance of human excreta by hand b~causeof (i) its availability at all human in tins or baskets and then feeding into settlements and at 10w/no cost and the the gas plants manually is therefore dire need for its treatment. While advoca- hmghly objec-tionable from the viewpomnt ting and recommending large scale use of the health of scavengers involved

* Sdentlst, NEERI, Nebru Marg, Nagpur - 440020

37 1 BIOGAS FROM HUMAN WASTE 1 proportion of methane in the shortest in the system. They come into direct possible time, the conditions ~f decomposi- çontact with the pathogens potentially tion in the digesters must be maintained 1 present in the excreta to be fed to biogas units. These ri~