Treatment of Leachate of Savar Solid Waste Landfill Site
Arifuzzaman1, Md. Mostafizur Rahman2, Farhana Akhter3
1Arifuzzaman, Department of Civil Engineering, University of Information Technology and Sciences UITS, Dhaka Bangladesh.
2Md. Mostafizur Rahman, Department of Civil Engineering, University of Information Technology and Sciences UITS, Dhaka Bangladesh.
3Farhana Akhter, Department of Civil Engineering, University of Information Technology and Sciences UITS, Dhaka Bangladesh.
Manuscript received on 12 October 2013 | Revised Manuscript received on 20 October 2013 | Manuscript Published on 30 October 2013 | PP: 108-112 | Volume-3 Issue-5, October 2013 | Retrieval Number: E1262103513/13©BEIESP
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© The Authors. Blue Eyes Intelligence Engineering and Sciences Publication (BEIESP). This is an open access article under the CC-BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)
Abstract: Landfill leachate is complex waste water with considerable variation in both quality and quantity. The composition and concentration of pollutants are influenced by the types of waste deposited, hydro geological factors and more significant by the age of the landfill site. In general, leachate is highly contaminated with organic contaminants measured as chemical oxygen demand (COD), biochemical oxygen demand (BOD) and also with high ammonium nitrogen concentration. Aerobic biological processes have been found the most effective and reliable treatment option of landfill leachate for developing country like Bangladesh. Leachate containing high concentrations of organic and nitrogen compounds results serious environmental problems near the landfill site. This research was undertaken to investigate the performance of both chemical treatment by alum coagulation and biological process that is extended–aeration activated sludge process without sludge return and anaerobic treatment of Savar Landfill leachate containing high organic and nitrogen concentrations. The main part of the study was studied on the removal efficiency of BOD, COD and ammonia in each method and heavy metals removal were also studied in coagulation and flocculation method. It is observed that in extended aeration process BOD removal is around 80% at 6 days detention time and 94% at 15 days detention time. In the same treatment method experiment results reveal that 75% of ammonia removal is achieved in 6 days aeration period mainly due to air stripping process and in total 98% removal is achieved in 15 days aeration period. The optimum pH of alum coagulant for leachate treatment was 6.5. Also an effective dosage of alum is 1.4 g/L for the best efficiency of heavy metals and COD removal. The maximum amount of COD and heavy metals that could be removed by the alum was about 21 and 77-91% of the initial value, respectively. It is also found that anaerobic biological treatment alone cannot efficiently remove the COD content of leachate from the site. BOD/COD ratio was varies from 0.19 to 0.14 in anaerobic batch system for 20 and 41 days, respectively. This BOD/COD ratio means low biodegradability of treated leachate. Chlorine oxidation, coagulation with high alum dose and extended aeration also conducted after construction of treatment facility by Dhaka City Corporation at Savar landfill site. Only 20 to 41 % COD removed in chlorine oxidation and alum coagulation. The second extended aeration results show that the dilution is not essential to treat leachate. It was taken a few days initially to convert the facultative microorganisms into aerobic microorganisms.
Keywords: Landfill Leachate, COD, Heavy Metals, Microorganisms.
Scope of the Article: Soil-Structure Interaction