title: Treatment of municipal landfill leachate using a combined anaerobic digester and activated sludge system.
abstract: The main objective of this study was to assess the feasibility of treating sanitary landfill leachate using a combined anaerobic and activated sludge system. A high-strength leachate from Shiraz municipal landfill site was treated using this system. A two-stage laboratory-scale anaerobic digester under mesophilic conditions and an activated sludge unit were used. Landfill leachate composition and characteristics varied considerably during 8 months experiment (COD concentrations of 48,552-62,150 mg/L). It was found that the system could reduce the COD of the leachate by 94% at a loading rate of 2.25g COD/L/d and 93% at loading rate of 3.37g COD/L/d. The anaerobic digester treatment was quite effective in removing Fe, Cu, Mn, and Ni. However, in the case of Zn, removal efficiency was about 50%. For the rest of the HMs the removal efficiencies were in the range 88.8-99.9%. Ammonia reduction did not occur in anaerobic digesters. Anaerobic reactors increased alkalinity about 3.2-4.8% in the 1st digester and 1.8-7.9% in the 2nd digester. In activated sludge unit, alkalinity and ammonia removal efficiency were 49-60% and 48.6-64.7%, respectively. Methane production rate was in the range of 0.02-0.04, 0.04-0.07, and 0.02-0.04 L/g COD(rem) for the 1st digester, the 2nd digester, and combination of both digesters, respectively; the methane content of the biogas varied between 60% and 63%.
authors.affiliation: Department of Civil & Environmental Engineering, University of Shiraz, Shiraz 7134851156, Iran.
authors.forename: S
authors.initials: S
authors.lastname: Kheradmand
authors.forename: A
authors.initials: A
authors.lastname: Karimi-Jashni
authors.forename: M
authors.initials: M
authors.lastname: Sartaj
mesh_terms: D001421:Bacteria, Anaerobic; D056804:Biofuels; D004787:Environmental Pollution / Q000517:prevention & control; D019216:Metals, Heavy / Q000032:analysis; D008697:Methane / Q000032:analysis; D010100:Oxygen / Q000378:metabolism; D012722:Sewage; D014874:Water Pollutants, Chemical / Q000378:metabolism*
chemical_list: D056804:Biofuels; D019216:Metals, Heavy; D012722:Sewage; D014874:Water Pollutants, Chemical; D008697:Methane; D010100:Oxygen