Methane Production from the Organic Fraction of Municipal Solid Waste Under Psychrophilic, Mesophilic, and Thermophilic Temperatures at Different Organic Loading Rates

Abstract

Methane production from the organic fraction of municipal solid waste (OFMSW) can be achieved under different operational conditions, but authors cannot conclude which conditions yield the best methane production. This research deals with how different organic loading rates (OLR) at different temperatures affect methane production during the anaerobic digestion of OFMSW. For 48 days, anaerobic granular sludge was adapted to OFMSW at 35 °C, and then, for another 85 days, using a semicontinuous digester, the mixture was further acclimated using OFMSW as substrate. This digestate was then used to inoculate three digesters at 55, 35, and 55 °C. The digesters were fed with OFMSW under different OLR. The digester at 55 °C reached stable methane production after 90 days at a low OLR. At 35 °C, methane production decreased with increasing OLR. At 20 °C, with increasing OLR, methane production declined as VFA concentration increased. The digester operating at 35 °C reached stable operation faster than the other two under the higher OLR. Slowly increasing the OLR allowed the adequate adaptation of the microorganisms to the substrate and temperature.