Physicochemical and biological treatability studies of urban solid waste leachate



In this research, physical, chemical and biological treatability of Tehran solid waste leachate was studied. Results indicate that the amount of COD for the fresh raw leachate of Tehran is equal to 66,608 mg/l. The leachate is transferred to an equalization tank for storage and pH control process. After neutralization, leachate is introduced to an up flow and down flow anaerobic reactor. The effluent of anaerobic reactor is conducted to a sequencing batch reactor. Sequence batch reactor (SBR) effluent was pumped in to sand and activated carbon filters, after chemical coagulation and clarification. Results showed that anaerobic reactor with detention time of 3 days had a 35% COD removal and increasing the detention time to 4.5 days would improve the COD removal to 45%. Nutrient adjustment with phosphorus and nitrogen increased the initial 23% efficiency of sequence batch reactor to 44%. The effluent COD of SBR reactor was 21,309 mg/l. Recycling of aerobic reactor effluent with incoming feed to anaerobic reactor reduced the anaerobic reactor influent COD to 20,000 mg/l and this caused 53% and 57% COD removal in the anaerobic and aerobic effluent, respectively. The total systems COD performance increased to 80% and SBR effluent COD eventually reduced to 4,000 mg/l. Coagulation, flocculation and sedimentation processes were practiced to make the 4,000 mg/l effluent COD comply with environmental standards of Iran. The optimum coagulant found to be ferric chloride with the dosage of 50 mg/l at pH of 12, which reduced 10% of COD to an amount of 3,676 mg/l. The effluent was stored in a tank and then pumped in to pressure sand filter and afterwards to activated carbon filter. The COD removal was three and 90% for sand and activated carbon filters, respectively. The total process reduced the remaining COD to 36 mg/l, which is in compliance with environmental standards of Iran.

Key words

Leachate SBR fixed bed aerobic and anaerobic treatment 


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  1. American Public Health Association (APHA), Standard methods for the examination of water and wastewater. 19th. Ed., Washington D. C., 1995Google Scholar
  2. Christensen, T. H., R. Cossu and R. Stegmarn, land filling of waste leachate, McGraw Hill Company, 1997Google Scholar
  3. Environmental Protection Agency, Manual groundwater and leachate treatment systems, EPA/625/R-94/005, No. 625R94005, 1994Google Scholar
  4. Henderson, J. P., D. A. Beslec, J. A. Atwater and D. S. Mavinic, Treatment of methanegenic landfill leachate to remove ammonia using a rotating biological contactor. J. Environ. Technol., l8 (7), 1997Google Scholar
  5. Hosomi, M., I. Yuhei, K. Matsushinge and R. Sudo, Denitrification of landfillleachate by the modified rotating biological contactor (RBC), Water Science and Technology, 23: 1477–1485, 1991Google Scholar
  6. Municipality of Tehran, Kahrizak leachate treatment studies. Organization of Waste Recycling and Composing, 2001Google Scholar
  7. Timur, H., I. Ozturk, M. Altinbas, O. Arikan and B. S. Tuyluoglu, Anaerobic treatability of leachate: A comparative evaluation for three different reactor systems. Water science and Technology, 42(1) & (2): 287–292, 2001Google Scholar

Copyright information

© Islamic Azad University 2004

Authors and Affiliations

  1. 1.Department of Environmental Engineering, Graduate School of the EnvironmentTehran UniversityTehranIran
  2. 2.Department of Environmental Engineering, Graduate School of the EnvironmentIslamic Azad UniversityTehranIran

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