ANAEROBIC TREATMENT OF LANDFILL LEACHATE TO OPTIMIZE METHANE
GENERATION
1
Syed E. Hasan, 2Suman Ghosh, and 2Namita Oswal
1,2
Department of Geosciences, University of Missouri-Kansas City, 5100 Rockhill Road, Kansas
City, MO 64110-2499; 1Phone: (816) 235-2976, E-mail: hasans@umkc.edu.
A partially bi-phasic, laboratory-scale anaerobic digester was designed and utilized for optimum
generation of methane, using a high strength landfill leachate with chemical oxygen demand
(COD) of 15,500 mg/L at a loading rate of 200 mL/day. The apparatus comprises a downflow
semi-continuous digester that was operated at mesophilic temperature (37  0.5 °C) where the
hydraulic retention time was maintained at 20 days. Modification to the conventional anaerobic
digestion was attempted by creating an aerobic phase two days prior to the effluent's entry into the
anaerobic system. This modification gave the digester sufficient buffering capacity to withstand
limited environmental stress and prevented generation of excess acid that could lead to a sour
condition and resulting failure. Simultaneous monitoring of selected volatile fatty acids helped in
optimizing the reaction conditions and maintaining stability of the digester. Experimental results
showed that the digester could be used successfully to treat landfill leachate with high COD, and is
capable of withstanding high loading rate and minor environmental shocks. The data showed a
total COD removal of 79% and a methane yield of 0.032 m3/kg of COD removal. Methane content
of the biogas varied between 35 and 39%.
Key words: bi-phasic anaerobic digester, landfill leachate, methane recovery