title: Reactor performance and bacterial pathogen removal in response to sludge retention time in a mesophilic anaerobic digester treating sewage sludge.
abstract: The effects of sludge retention time (SRT) on reactor performance and bacterial pathogen removal of sludge mesophilic anaerobic digestion (MAD) were investigated in a continuous stirred tank reactor. The average volatile solids removal remained around 20% and the biogas production rate varied from 100 to 132ml/ld. The MAD process was efficient to remove Salmonella sp. and Escherichia coli with removal efficiencies increased with SRT from 11d, 16d to 25d. However, the Shigella sp. removal was insignificant. The difference in the resistance of the three pathogens to sludge MAD process is helpful to the selection of pathogen indicators in the biosolids. Log reduction of pathogens determined by MPN was much higher than the data by quantitative PCR, suggesting the presence of viable but non-culturable pathogen cells. This study confirms that the control of appropriate SRT for sludge MAD should take both reactor performance and pathogen removal into account.
authors.affiliation: Laboratory of Environmental Biotechnology, School of Environmental and Civil Engineering, Jiangnan University, Wuxi 214122, Jiangsu Province, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Chen
authors.forename: Bo
authors.initials: B
authors.lastname: Fu
authors.forename: Yan
authors.initials: Y
authors.lastname: Wang
authors.forename: Qian
authors.initials: Q
authors.lastname: Jiang
authors.forename: He
authors.initials: H
authors.lastname: Liu
mesh_terms: D000693:Anaerobiosis; D001419:Bacteria / Q000235:genetics / Q000302:isolation & purification*; D001673:Biodegradation, Environmental; D056804:Biofuels; D057919:Biological Oxygen Demand Analysis; D019149:Bioreactors / Q000382:microbiology* / Q000592:standards*; D004926:Escherichia coli / Q000235:genetics / Q000302:isolation & purification; D006863:Hydrogen-Ion Concentration; D060888:Real-Time Polymerase Chain Reaction; D012037:Refuse Disposal / Q000295:instrumentation* / Q000379:methods*; D012475:Salmonella / Q000235:genetics / Q000302:isolation & purification; D012722:Sewage / Q000382:microbiology*; D012760:Shigella / Q000235:genetics / Q000302:isolation & purification; D013997:Time Factors; D014835:Volatilization
chemical_list: D056804:Biofuels; D012722:Sewage