title: Anaerobic treatment of municipal wastewater at ambient temperature: Analysis of archaeal community structure and recovery of dissolved methane.
abstract: Anaerobic treatment is an attractive option for the biological treatment of municipal wastewater. In this study, municipal wastewater was anaerobically treated with a bench-scale upflow anaerobic sludge blanket (UASB) reactor at temperatures from 6 to 31 °C for 18 months to investigate total chemical oxygen demand (COD) removal efficiency, archaeal community structure, and dissolved methane (D-CH(4)) recovery efficiency. The COD removal efficiency was more than 50% in summer and below 40% in winter with no evolution of biogas. Analysis of the archaeal community structures of the granular sludge from the UASB using 16S rRNA gene-cloning indicated that after microorganisms had adapted to low temperatures, the archaeal community had a lower diversity and the relative abundance of acetoclastic methanogens decreased together with an increase in hydrogenotrophic methanogens. D-CH(4), which was detected in the UASB effluent throughout the operation, could be collected with a degassing membrane. The ratio of the collection to recovery rates was 60% in summer and 100% in winter. For anaerobic treatment of municipal wastewater at lower temperatures, hydrogenotrophic methanogens play an important role in COD removal and D-CH(4) can be collected to reduce greenhouse gas emissions and avoid wastage of energy resources.
authors.affiliation: Division of Environmental Engineering, Faculty of Engineering, Hokkaido University, North-13, West-8, Kita-ku, Sapporo 060-8628, Japan.
authors.forename: Wasala M K R T W
authors.initials: WMKRTW
authors.lastname: Bandara
authors.affiliation: Department of Civil and Environmental Engineering, Graduate School of Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashihiroshima, Hiroshima 739-8527, Japan.
authors.forename: Tomonori
authors.initials: T
authors.lastname: Kindaichi
authors.affiliation: Division of Environmental Engineering, Faculty of Engineering, Hokkaido University, North-13, West-8, Kita-ku, Sapporo 060-8628, Japan. Electronic address: qsatoh@eng.hokudai.ac.jp.
authors.forename: Hisashi
authors.initials: H
authors.lastname: Satoh
authors.affiliation: Mitsubishi Rayon Co., Ltd., Aqua Development Center, 4-1-2 Ushikawadori, Toyohashi, Aichi 440-8601, Japan.
authors.forename: Manabu
authors.initials: M
authors.lastname: Sasakawa
authors.affiliation: Mitsubishi Rayon Co., Ltd., Aqua Development Center, 4-1-2 Ushikawadori, Toyohashi, Aichi 440-8601, Japan.
authors.forename: Yoshihito
authors.initials: Y
authors.lastname: Nakahara
authors.affiliation: Division of Environmental Engineering, Faculty of Engineering, Hokkaido University, North-13, West-8, Kita-ku, Sapporo 060-8628, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Takahashi
authors.affiliation: Division of Environmental Engineering, Faculty of Engineering, Hokkaido University, North-13, West-8, Kita-ku, Sapporo 060-8628, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Okabe
mesh_terms: D000693:Anaerobiosis; D001105:Archaea / Q000235:genetics / Q000378:metabolism*; D008697:Methane / Q000737:chemistry* / Q000378:metabolism*; D012336:RNA, Ribosomal, 16S; D013696:Temperature; D014865:Waste Disposal, Fluid / Q000379:methods*
chemical_list: D012336:RNA, Ribosomal, 16S; D008697:Methane