Mesophilic and thermophilic anaerobic digestion of municipal sludge and fat, oil, and grease.

The anaerobic biodegradability of municipal primary sludge, thickened waste activated sludge (TWAS), and fat, oil, and grease (FOG) was assessed using semi-continuous-feed, laboratory-scale anaerobic digesters and compared with the ultimate degradability obtained from 120-day batch digestion at 35 degrees C. In run 1, combined primary sludge and TWAS (40/60%, volatile solids [VS] basis) were fed to digesters operated at mesophilic (35 degrees C) and thermophilic (52 degrees C) temperatures at loading rates of 0.99 and 1.

Methane recovery from the anaerobic codigestion of municipal sludge and FOG.

The anaerobic biodegradability of a mix of municipal primary sludge (PS), thickened waste activated sludge (TWAS) and fat, oil, and grease (FOG) was assessed using semi-continuous feed, laboratory-scale anaerobic digesters operated at mesophilic (35 degrees C) and thermophilic (52 degrees C) temperature. Addition of a large FOG fraction (48% of the total VS load) to a PS+TWAS mix, resulted in 2.95 times larger methane yield, 152 vs.