title: Production of biologically safe digested manure for land application by a full-scale biogas plant with heat-inactivation.
abstract: Inactivation of indigenous indicator micro-organisms such as faecal coliforms, coliphages, and faecal streptococci was investigated in a full-scale biogas plant that mainly digested cow manure. The biogas plant consisted principally of a feed reservoir, fermentation tank (37 degrees C), heat-inactivation process (70 degrees C), and five reservoirs for the heat-inactivated, digested manure that was used by a local livestock farmer as liquid fertilizer. Although all the indicators tended to exhibit stepwise decreases with each stage of treatment, coliphages were found to be more capable of surviving than faecal coliforms and faecal streptococci under mesophilic anaerobic conditions as well as high temperature conditions (heat-inactivation at 70 degrees C). Liquid fertilizer produced at the biogas plant had faecal coliform densities less than the stipulations of the US EPA 40 CFR 503 Class A limits. Heat-inactivation tests indicated that although coliphages exhibited more tolerance than other bacterial indicators between 37 and 70 degrees C, they were more sensitive to continuous temperature increase than faecal coliforms and faecal streptococci.
authors.affiliation: Department of Civil and Environmental Engineering, Kisarazu National College of Technology, Kisarazu, Chiba, Japan. uemura@wangan.c.kisarazu.ac.jp
authors.forename: Shigeki
authors.initials: S
authors.lastname: Uemura
authors.forename: Akiyoshi
authors.initials: A
authors.lastname: Ohashi
authors.forename: Hideki
authors.initials: H
authors.lastname: Harada
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Hoaki
authors.forename: Takashi
authors.initials: T
authors.lastname: Tomozawa
authors.forename: Takahiko
authors.initials: T
authors.lastname: Ohara
authors.forename: Reiichi
authors.initials: R
authors.lastname: Ojima
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Ishida
mesh_terms: D004755:Enterobacteriaceae / Q000378:metabolism*; D005285:Fermentation; D005308:Fertilizers; D006358:Hot Temperature; D008372:Manure; D014481:United States; D014484:United States Environmental Protection Agency
chemical_list: D005308:Fertilizers; D008372:Manure