Semi-continuous anaerobic co-digestion of thickened waste activated sludge and fat, oil and grease

• Published in: Waste management (Elmsford) 2011-08, Vol.31 (8), p.1752-1758
• Main Authors: Wan, Caixia, Zhou, Quancheng, Fu, Guiming, Li, Yebo
• Format: Article
• Language: English
• Subjects: 09 BIOMASS FUELS; Activated sludge; ALKANES; Anaerobic; ANAEROBIC DIGESTION; Anaerobiosis; Applied sciences; BIOCONVERSION; Biofuels - analysis; Bioreactors; CARBON COMPOUNDS; CARBON DIOXIDE; CARBON OXIDES; CHALCOGENIDES; co-Digestion; DIGESTION; Exact sciences and technology; FATS; Fats - metabolism; Fog; GREASES; Humans; HYDROCARBONS; INHIBITION; Lipid Metabolism; Lipids; LOADING RATE; LUBRICANTS; MESOPHILIC CONDITIONS; METHANE; Methane - analysis; Methane - biosynthesis; Micronutrients; OILS; Oils - metabolism; ORGANIC COMPOUNDS; Other industrial wastes. Sewage sludge; OTHER ORGANIC COMPOUNDS; Other wastes and particular components of wastes; OXIDES; OXYGEN COMPOUNDS; Pollution; Refuse Disposal - methods; Sewage - chemistry; SLUDGES; STABILIZATION; Steady state; STEADY-STATE CONDITIONS; Waster activated sludge; WASTES
• ISSN: 0956-053X; 1879-2456
• DOI: 10.1016/j.wasman.2011.03.025

► Co-digestion of thickened waste activated sludge (TWAS) with fat, oil and grease (FOG). ► Co-digestion of TWAS and FOG at 64% VS increased biogas production by 137%. ► FOG addition ratio at 74% of total VS caused inhibition of the anaerobic digestion process. ► Micronutrients addition did not significantly improve the biogas production and digestion stabilization. Co-digestion of thickened waste activated sludge (TWAS) and fat, oil and grease (FOG) was conducted semi-continuously under mesophilic conditions. The results showed that daily methane yield at the steady state was 598 L/kg VS added when TWAS and FOG (64% of total VS) were co-digested, which was 137% higher than that obtained from digestion of TWAS alone. The biogas composition was stabilized at a CH 4 and CO 2 content of 66.8% and 29.5%, respectively. Micronutrients added to co-digestion did not improve the biogas production and digestion stabilization. With a higher addition of FOG (74% of total VS), the digester initially failed but was slowly self-recovered; however, the methane yield was only about 50% of a healthy reactor with the same organic loading rate.