Full-Scale Mesophilic Anaerobic Co-Digestion of Municipal Solid Waste and Sewage Sludge: Methane Production Characteristics

Abstract

The methane production characteristics of a full scale anaerobic biogas digester processing the putrescible fraction of municipal solid waste (PFMSW) and sewage sludge (SS) were studied by using the operation data of the digester and laboratory experiments. The batch assays indicated methane yields of 3001 kg volatile solids (VS) ^-1 for PFMSW and 2201 kg VS^-1 for SS. The full scale digester showed methane production yields up to 90% of the methane yield potential of the added feed. The rates of methane production and the specific methanogenic activities varied during the cycle of feeding. Apparently, the methanization in the digestion process was substrate-limited, especially during weekends when no feed was added. The batch studies indicated that the propionate and butyrate conversions were no more limiting than acetate methanization. The sludge from the digester was more active than the sludges from digesters processing sewage sludge alone. © 1996 ISWA