title: The anaerobic biodegradability of municipal sludge and fat, oil, and grease at mesophilic conditions.
abstract: The anaerobic biodegradability of municipal primary and secondary sludge with increasing levels of partially dewatered fat, oil, and grease (FOG) was assessed using a mixed methanogenic culture at 35 "C. Under batch conditions with an acclimated and enriched microbial population, the sludge loading was 3 kg volatile solids/m3 and the highest FOG loading tested was 1.5 kg volatile solids/m3, resulting in a methane yield of 245 mL methane/g sludge volatile solids added at 35 degrees C and 1010 mL methane/g FOG volatile solids added at 35 degrees C. Under semicontinuous feeding conditions, the sludge and sludge plus FOG loading tested were 3 and 3.75 kg volatile solids/m3-d, respectively. Within 23 days of operation, the volatile fatty acid concentrations were reduced below 200 mg chemical oxygen demand/L (187 mg/L as acetic acid). Enhancement of sludge digestion was observed in those reactors where codigestion of sludge and FOG took place, which was attributed to a higher level of microbial activity maintained in these reactors as a result of FOG degradation. The results of this study demonstrate that beneficial use of FOG through codigestion with municipal sludge is feasible.
authors.affiliation: Carollo Engineers, 401 North Cattlemen Road, Sarasota, FL 34232, USA. JKabouris@carollo.com
authors.forename: John C
authors.initials: JC
authors.lastname: Kabouris
authors.forename: Ulas
authors.initials: U
authors.lastname: Tezel
authors.forename: Spyros G
authors.initials: SG
authors.lastname: Pavlostathis
authors.forename: Michael
authors.initials: M
authors.lastname: Engelmann
authors.forename: Allen C
authors.initials: AC
authors.lastname: Todd
authors.forename: Robert A
authors.initials: RA
authors.lastname: Gillette
mesh_terms: D000693:Anaerobiosis; D001673:Biodegradation, Environmental; D019149:Bioreactors; D005227:Fatty Acids / Q000378:metabolism; D006801:Humans; D050356:Lipid Metabolism; D008697:Methane / Q000378:metabolism; D012722:Sewage; D018508:Water Purification / Q000379:methods*
chemical_list: D005227:Fatty Acids; D012722:Sewage; D008697:Methane