title: Semi-continuous mesophilic anaerobic digester performance under variations in solids retention time and feeding frequency.
abstract: The goal of this research was to understand the effect of solids retention time (SRT) and feeding frequency on the performance of anaerobic digesters used to recover bioenergy from swine waste. Semi-continuous mesophilic anaerobic digesters were operated at varying SRTs and feeding frequencies. Performance metrics included biogas and methane production rates, biomass robustness and functionality and removals of volatile solids, soluble chemical oxygen demand, the fecal-indicator bacteria Escherichia coli, and the human pathogen Salmonella. Biochemical methane formation potential and specific methanogenic activity assays were used to demonstrate biomass robustness and functionality. Results indicated that anaerobic digesters fed weekly had higher average methane yields (0.20 vs. 0.18m(3)CH4/kg-VSadded), specific methanogenic activities (40 vs. 35ml/day), and fecal indicator bacteria destruction (99.9% vs. 99.4%) than those fed every-other day. Salmonella, soluble COD, and VS destruction did not change with varied feeding frequency; however, higher removals were observed with longer SRT.
authors.affiliation: Department of Civil and Environmental Engineering, University of South Florida, 4202 E Fowler Avenue, ENB 118, Tampa, FL 33620, United States.
authors.forename: Nathan D
authors.initials: ND
authors.lastname: Manser
authors.affiliation: Department of Civil and Environmental Engineering, University of South Florida, 4202 E Fowler Avenue, ENB 118, Tampa, FL 33620, United States.
authors.forename: James R
authors.initials: JR
authors.lastname: Mihelcic
authors.affiliation: Department of Civil and Environmental Engineering, University of South Florida, 4202 E Fowler Avenue, ENB 118, Tampa, FL 33620, United States. Electronic address: sergas@usf.edu.
authors.forename: Sarina J
authors.initials: SJ
authors.lastname: Ergas
mesh_terms: D000818:Animals; D001421:Bacteria, Anaerobic / Q000302:isolation & purification* / Q000378:metabolism*; D001673:Biodegradation, Environmental; D019149:Bioreactors / Q000382:microbiology*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D008372:Manure / Q000382:microbiology*; D008697:Methane / Q000378:metabolism*; D012037:Refuse Disposal / Q000295:instrumentation*; D013552:Swine
chemical_list: D008372:Manure; D008697:Methane
keywords: Anaerobic digester operations; International sustainable development; Methanogenic activity; Pathogen removal; Swine waste