International Journal of Physical Sciences Vol. 7(30), pp. 5162 - 5166, 9 August, 2012 Available online at http://www.academicjournals.org/IJPS DOI: 10.5897/IJPS12.309 ISSN 1992 -1950 ©2012 Academic Journals

Full Length Research Paper

Macrophyte waste stabilization : An option for municipal

Mumtaz Shah1* and Hashim Nisar Hashmi2

1Department of Civil and Environmental Engineering, University of Engineering and Technology (UET) Taxila, Pakistan. 2Department of Civil Engineering, University of Engineering and Technology (UET) Taxila, Pakistan.

Accepted 3 August, 2012

The objective of this research is to evaluate the performance of macrophyte waste stabilization system for municipal wastewater collected from Taxila (Pakistan). A model of macrophyte waste stabilization pond system was operated for six trials with each trials comprising different detention times that is 3, 5, 7 and 10 days, respectively. For the treatment, locally available macrophyte (water hyacinth) was used. To evaluate the performance of macrophyte waste stabilization pond, BOD5, TDS, TSS, COD, faecal coliform and for the effluent from pond model were measured at each detention time of every trial after ensuring steady state conditions. The influent values of same parameters have been measured at the start of each trial as the wastewater sample was collected from the municipal sewer. The average reduction of effluent value of each parameter varies from 30 to 48%, that is BOD5 (48%), TDS (31%), TSS (30%), COD (42%), faecal coliform (45%), and Nitrogen (40%). The mechanisms of removal in this system include both aerobic and anaerobic microbiological conversions, sorption, sedimentation, volatilization and chemical transformations. There is currently no macrophyte wastewater waste stabilization pond system under study/practice in many of the developing countries; therefore, for the promotion of macrophyte based waste stabilization system detailed pilot scale studies should be conducted for municipal under local environmental conditions to explore the treatment efficiency of the system. Also, it is necessary that macrophyte system be used as treatment facility for wastewater because their performance is comparable to conventional wastewater treatment plants and since the system has very low operation and maintenance costs.

Key words: BOD5, Eicchornia crassipes, macrophytes, municipal sewage, water hyacinth, wastewater treatment.

INTRODUCTION

Pakistan is located in a severe water-scarce zone, which are electricity shortages and lack of skilled operators. increases the scope of the wastewater treatment and its Oxidation ponds have been found to be an effective means reuse. Treatment plant has been constructed and being of low cost treatment of domestic and industrial wastewater, operated in different cities of Pakistan; however, due to especially for those countries lying in tropical and subtropical financial constraints, non availability of skilled operators and regions of the world (Kharkar et al., 1972). The oxidation electricity shortages most of them are in a non-functional pond treatment technology has been recommended by a condition (Aziz, 2005). Treatment plants have been installed number of workers (McGarry and Pescod, 1970; Mara, 1975; in almost every large city of Pakistan, like Karachi (Two 20 Oswald, 1975; Middlebrooks et al., 1981). The technology MGD wastewater treatment plants employing trickling filters) has an edge over the mechanical systems as being and Islamabad (a 5 MGD capacity activated plant), technologically very simple, economically very cost effective although most of them are non functional as far as and a higher degree of removal is achieved. The performance is concerned. The main reasons of their failure conventional wastewater treatment plants are very efficient in removing suspended solids and organic matter (more than 85%) and usually very poor in removing nitrogen, phosphorous, heavy metals, non-biodegradable *Corresponding author. E-mail: [email protected]. Tel: organics, and . Oxidation ponds have been +923414400046. employed for the treatment of wastewater for over 3000 Shah and Hashmi 5163

Table 1. Summary of wastewater treatment plant in Pakistan.

Characteristics Treatment plants Treatment technology Trickling filter - Karachi Trickling filter - Karachi Aerated - Karachi -Islamabad Year of construction 1963 1965 1985 1962 Location TPI Sher Shah TPII Mahmoodabad North Karachi Islamabad Capacity 20 MGD 20 MGD 5 MGD 5 MGD Type Two stage high rate Two stage high rate — — Design and Make Dorr Oliver, Holland Dorr Oliver, Holland Karachi Development Authority — Primary 4 (138 ft dia, 12 ft) deep 4 (138 ft dia, 12 ft) deep 2 (35 ft × 20 ft) 2 (18 ft dia, 9 ft deep) Trickling filter 8 (136 ft dia, 7 ft deep) 8 (136ft dia, 12 ft deep) — — Secondary clarifier 4 (128 ft dia, 12 ft deep) 4 (138 ft dia, 12 ft deep) 2 (63 ft × 30 ft) 2 (120 ft dia, 12 ft deep) Aerator — — 16 ( requirement = 980 kg/day) — Aeration unit/ Aeration tank — — 4 (Semi corrusel 6.5 ft deep, 1.25 MGD) 2 (111 x 30 × 18 ft) Capital cost million Rs. 30.5 30.2 15.85 8.0 Operation and maintenance 0.084 0.084 0.168 0.275 cost per year (Million Rs.) Present status Non operative Non operative Non operative Non operative

WASA & NESPAK (2002).

years. Similarly, by employing the macrophyte in waste MATERIALS AND METHODS stabilization ponds their efficiency can be further enhanced. Macrophytes are common features of an aquatic . All the primary treated effluent is sent to the inlet zone of the model whereby passing through the wastewater reaches the main tank where Various types of macrophytes are generally observed in an it gets treatment with macrophyte (water hyacinth) under different such as Floating plants (Eichhornia detention times (3, 5, 7 and 10 days). After adding water hyacinth to crassipes (Water Hyacinth), Spirodela (Duckweed), Salvinia the pond model different parameters of wastewater was monitored molesta (Salvinia) and Emergent plants (Schoenoplectus for both the raw sewage as as for the wastewater treated by validus (Great Bulrush), Juncus ingens (Giant Rush), water hyacinth in the model. Both the raw sewage as well as the treated effluent has been tested for a set of parameters (BOD5, Phragmites (Common Reed), Typha spp. (Cumbungi or TDS, TSS, COD, faecal coliform and Nitrogen). All tests performed Cattail). For the developing countries that have limited on the wastewater were carried out according to the procedures resources for the construction and operation of conventional laid down in “Standard Methods for the Examination of Water and treatment plants, waste stabilization pond with macrophyte is Wastewater” (20th edition, 1998). Monthly average air temperature the most economical solution. Additional benefits are that during the whole period of sampling varied between 25 and 29.4°C with they serve as wildlife habitat and recreation purposes. The an average of 26.9°C. The initial values of the selected parameters for raw sewage are given in Table 2. cost effective method of treatment makes it a potentially economical and suitable option for bio- and phyto- remediation. Description of the treatment system In Pakistan, the wastewater treatment plants installed in major cities are mostly non operative due to the non The work reported here was carried out during the dry season from availability of the skilled workforce as well as due to electricity April 2011 until June 2011. All effluent collected from the municipal crisis. The details of some of the plants are given in Table 1. sewer was first sent to a primary settling tank and then after passing through it is distributed in to a lagoon having the Currently in Pakistan, waste stabilization ponds with macrophyte (water hyacinth). The effluent has been retained for 3, macrophyte have not yet been recognized as a treatment 5, 7 and 10 days in lagoon during each trail, and total of six trials option for the wastewater treatment. Failure for the has been performed. After completion of each detention time acceptance is due to the lack of information, research work sample was collected from lagoon and tested for effluent quality. and government policy to prove the effectiveness of the The plants in lagoon were harvested two to three times per week. At each detention, the following parameters were measured during system for wastewater treatment. Pakistan has wide area daytime: BOD5, (COD), total dissolved under natural wetlands in coastal areas of Sindh and solids (TDS), (TSS), nitrogen, faecal coliform Baluchistan province in form of mangrove forests that can be and pH. All analyses were done according to Standard Methods for successfully used for treatment and polishing. In the the Examination of Water and Wastewater (1995). Monthly average proposed study the municipal wastewater of Taxila (Punjab, air temperature during the whole period of sampling varied between Pakistan) is taken for treatment from a bench scale laboratory 25 and 29.4°C with an average of 26.9°C. The plants maintained a surface covering of 80 to 100%. The plants were quite fragile; they model of a macrophyte waste stabilization pond. Since water cannot resist too much handling during collection and hyacinth is the only locally available macrophyte therefore, transportation. The construction detail of the lagoon is given below the same has been chosen for the study. in the Table 3. The Schematic Diagram of the system is shown in 5164 Int. J. Phys. Sci.

Figure 1. Schematic diagram of the treatment system.

Table 2. Raw sewage values.

S/N Parameter Unit Value Standard deviation

1 BOD5 mg/L 132 23 2 COD mg/L 236.33 41.29 3 Nitrogen mg/L 2.65 1.0 4 TDS mg/L 723.33 70.62 5 TSS mg/L 98 7.18 6 Faecal coliform No./100 ml 1361.67 320.53

Figure 1. collected samples are used to compare the percentage

degree of treatment by macrophytes under different RESULTS AND DISCUSSION detention times. The results demonstrate the removal efficiencies of the Average pollutant concentrations of the treated effluent waste stabilization pond system expressed as samples collected at different detention times during six percentage of input concentration. The results clearly trials is given in Table 4. Effluent concentrations of all the indicates average reduction of 30% in TDS, 31% in TSS, Shah and Hashmi 5165

Table 3. Model characteristics.

S/N Characteristics Unit Value 1 Depth ft 4 2 Length ft 18 3 Width ft 6 4 Cross section -- Trapezoidal 5 Retention time days Variable

Table 4. Results of treated effluent.

Concentration Detention Trials TDS TSS Nitrogen BOD5 COD Faecal coliform Average reduction (days) pH (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (No./100 ml) 3 8.4 810 84 1.06 106.9 180 904.7 TDS = 5% TSS = 59% 5 8.2 800 70 0.93 97.8 166 839.3 Nitrogen = 33% 1 7 7.7 790 54 0.80 82.3 130 654 BOD5 = 41% COD = 63% 10 7.5 780 42 0.71 76 84 599.5 F-Coli = 45%

3 8.4 694 77 2.80 124 227 946.2 TDS = 30% TSS = 31% 5 8.1 624 71 2.40 112 203 877.8 Nitrogen = 32% 2 7 7.6 601 65 2.11 91 189 684 BOD5 = 48% COD = 40% 10 7.3 546 62 1.91 79 162 627 F-Coli = 45%

3 8 486 82 2.3 78 143 1195.2 TDS = 30% TSS = 31% 5 7.9 436.8 75 2.2 70 128 1108.8 Nitrogen =41% 3 7 7.7 420 68 2.2 57 119 864 BOD5 = 47% COD = 40% 10 7.5 382.2 66 2 50 102 792 F-Coli = 45%

3 8 340 95 2.85 101 185 1494 TDS = 30% TSS = 31% 5 7.9 305.76 87 2.50 91 165 1386 Nitrogen = 40% 4 7 7.7 294 79 2.11 74 154 1080 BOD5 = 48% COD = 40% 10 7.5 267.54 76 1.92 64 132 990 F-Coli = 45%

3 7 238 84 1.07 110 202 863 TDS = 30% TSS = 31% 5 6.9 214.032 77 0.94 99 180 801 Nitrogen =40% 5 7 6.9 206 71 0.79 81 168 624 BOD5 = 48% COD = 40% 10 6.5 187.278 68 0.72 70 144 572 F-Coli = 45%

3 7 163 79 2.49 131 245 1361 TDS = 31% TSS = 34% 5 6.9 149.8224 71 2.18 118 219 1262 Nitrogen = 40% 6 7 6.9 142 66 1.85 96 204 1014 BOD5 = 48% COD = 38% 10 6.5 129.2218 61 1.68 83 179 929.6 F-Coli = 44%

5166 Int. J. Phys. Sci.

40% in Nitrogen, 48% in BOD5, 42% in COD and 45% in 5) The macrophyte wastewater stabilization pond system faecal coliform. The results show higher removal should be promoted for the municipal wastewater efficiency for the Nitrogen, BOD5 and faecal coliform; treatment of developing countries as it reduces the major however, removal of TDS and TSS is not much as wastewater pollutant to a large extent. Additionally, this expected. system of treatment is also self sustainable which is a The results shows after three days of detention there is main reason for opting for this system than other not much reduction in pollutant values but as the mechanized systems. This will help in protecting the detention time increase the reduction of pollutant in the water sources from the pollution as well. sewage also increase. During the entire study water hyacinth shows a good growth rate; however, their growth is affected due to the decrease in temperature, REFERENCES that is, during winter. Therefore the system shows Aziz JA (2005). Management of source and drinking- in excellent performance during the summer season and so Pakistan. Eastern Med. Health J. 11:5-6. it can be used for the treatment of municipal wastewater Kharkar CB, Venkatesam TL, Tiwari AR (1972). Review of performance of developing countries like Pakistan having tropical of the stabilization ponds at Bhilai. In: Proceedings of the symposium environment. of low cost waste treatment, India. Mara DD (1975). Proposed design for oxidation ponds in hot climates. Jour Inc. New York. McGarry MG, Pescod MB (1970). Stabilization pond design criteria for Conclusions tropical Asia. In: 2nd International Symposium for waste treatment , Kansas City. Middlebrooks J, Middlebrooks CH, Reynods JH, Watters GZ, Reed SC, 1) In many developing countries municipal George DB (1981). Wastewater stabilization lagoon designing systems carry mixed wastewater rich in inorganic and performance and upgrading. Macmillan, N. Y. organic toxic which may inhibit microbial Oswald WJ (1975). Experience with new pond design in California. processes, and hence reduce the macrophyte based Presented before the conference "Ponds as wastewater treatment alternative. University of Texas. Austin. treatment system efficiency. Characteristics of the WASA & NESPAK (2002). Lahore Master Plan. Lahore Development wastewater to be treated must be considered in the Authority (LDA). Pakistan. design. 2) Appropriate choice of species adapted to tropical environments is of great significance. In the tropics where growth rates are high, the frequency and hence the cost of harvesting has to be considered. Economic utilization of excess biomass and frequent harvesting costs should be well assessed before choosing such a plant. 3) Currently in Pakistan almost all installed mechanized wastewater treatment systems are not working properly due to operation and maintenance problems associated with these systems. Therefore there is dire need to search for an alternative wastewater treatment system like macrophyte waste stabilization pond system using the local macrophyte species for wastewater treatment.

4) The main reasons for opting for the macrophyte based treatment system includes commercial value of biomass. The sludge from the macrophyte waste stabilization pond can be used as fertilizer after some primary precautions and the sludge can be used for producing energy by .