Effective anaerobic biodegradation of municipal solid waste fresh leachate using a novel pilot-scale reactor: Comparison under different seeding granular sludge

A novel integrated internal and external circulation (IIEC) reactor was developed for anaerobic biodegradation of municipal solid waste (MSW) fresh leachate with chemical oxygen demand (COD) between 40,000 and 60,000 mg/l. The pilot-scale IIEC reactor was inoculated with two kinds of granular sludge from paper mill (S-PM) and from citric acid factory (S-CF), respectively. The bio-treating capacity in contaminant removal and biogas production performed much superior to others' results, principally attributed to appropriate configuration modification. Compared to S-CF, much higher organic loading rate (40.5 vs 23.0 kg COD/m(3) d) and COD removal efficiency (>80% vs 60-75%) were achieved for the reactor with S-PM. For methane production, 11.77 or similar to 6 m(STP)(3)/m(3) d of rate and 66-85% of content were observed with S-PM or S-CF, respectively. Due to better sludge concentrations and methanogenic activity, these findings indicate the anaerobic reactor could effectively bio-treat MSW leachate for methane generation, especially inoculated with granular sludge derived from leachate-like-wastewater. (C) 2014 Elsevier Ltd. All rights reserved.