title: Long-term performance evaluation of down-flow hanging sponge reactor regarding nitrification in a full-scale experiment in India.
abstract: The first full-scale down-flow hanging sponge (DHS) reactor applied to post-treatment of effluent from an upflow anaerobic sludge blanket (UASB) reactor for the treatment of municipal sewage was evaluated, with emphasis on nitrification. The full-scale DHS reactor was successfully operated at a hydraulic retention time of 1.5h for over 1800 days in India. The DHS reactor produced effluent with 6 mg L(-1) ammonium nitrogen, corresponding to 79% removal efficiency. The total nitrogen removal by the DHS reactor was 65%. The high process performance of the DHS reactor was supported by its distinctive characteristics of (1) high dissolved oxygen of 5.4 mg L(-1) in the DHS effluent without forced ventilation, (2) dense retained sludge in the range of 23-46 gVSS Lsponge(-1), and (3) adequate sludge activity of 52 mgN gVSS(-1) day(-1) for nitrification. The full-scale experiment has proven that the DHS reactor has practical applicability to developing countries.
authors.affiliation: Department of Regional Environmental Research Center, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-8506, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Onodera
authors.affiliation: Department of Civil and Environmental Engineering, National Institute of Technology, Kisarazu College, 2-11-1 Kiyomidaihigashi, Kisarazu, Chiba 292-0041, Japan.
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Okubo
authors.affiliation: Department of Civil and Environmental Engineering, National Institute of Technology, Kisarazu College, 2-11-1 Kiyomidaihigashi, Kisarazu, Chiba 292-0041, Japan.
authors.forename: Shigeki
authors.initials: S
authors.lastname: Uemura
authors.affiliation: Department of Civil and Environmental Engineering, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka, Niigata 940-2188, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Yamaguchi
authors.affiliation: Department of Social and Environmental Engineering, Hiroshima University, 1-4-1 Kagamiyama Higashi, Hiroshima 739-8527, Japan.
authors.forename: Akiyoshi
authors.initials: A
authors.lastname: Ohashi
authors.affiliation: New Industry Creation Hatchery Center, Tohoku University, 6-6-04 Aoba, Aramakiaza, Aoba-ku, Sendai, Miyagi 980-8579, Japan. Electronic address: hideki.harada.e3@tohoku.ac.jp.
authors.forename: Hideki
authors.initials: H
authors.lastname: Harada
mesh_terms: D000693:Anaerobiosis; D057919:Biological Oxygen Demand Analysis; D019149:Bioreactors; D007194:India; D058465:Nitrification; D009584:Nitrogen / Q000032:analysis / Q000737:chemistry; D012722:Sewage; D018505:Waste Management / Q000295:instrumentation / Q000379:methods*
chemical_list: D012722:Sewage; D009584:Nitrogen
keywords: Developing countries; Down-flow hanging sponge; Full-scale experiment; Municipal sewage; Nitrification