Anaerobic sequencing batch reactor treatment of landfill leachate

Anaerobic treatability of municipal landfill leachate was evaluated using lab-scale anaerobic sequencing batch reactors (ASBR) at 35 °C. Experimental studies were conducted at wide-range of volumetric (0.4-9.4 g COD l^-1 d^-1) and specific (0.2-1.9 g COD g^-1 VSS d^-1) loading rates by varying hydraulic retention times (HRT) (10-1.5 days) and influent wastewater COD's (3800-15900 mg l^-1). The COD removal efficiencies were in the range of 64-85% depending on volumetric and specific loading rates applied. The net daily biomass conversion yields were about 0.1 g volatile suspended solids (VSS) per g of COD removed. Bacterial decay rate constant was 0.01 d^-1. The maximum volumetric methane production rate (VMPR) of 1.851 CH₄ l^-1 d^-1 was achieved at the volumetric loading rate of 9.4 g COD l^-1 d^-1. The specific methane production rates in terms of COD were about 1.06 g CH₄-COD g VSS^-1 d^-1 in the reactor. The results have shown that about 83% of COD removed during the treatment was converted to methane. The average biomass yield was determined as 0.12 g VSS per gram of COD removed.