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 CODʹs (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 1.85 l 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.