title: Development of downflow hanging sponge (DHS) reactor as post treatment of existing combined anaerobic tank treating natural rubber processing wastewater.
abstract: Conventional aerated tank technology is widely applied for post treatment of natural rubber processing wastewater in Southeast Asia; however, a long hydraulic retention time (HRT) is required and the effluent standards are exceeded. In this study, a downflow hanging sponge (DHS) reactor was installed as post treatment of anaerobic tank effluent in a natural rubber factory in South Vietnam and the process performance was evaluated. The DHS reactor demonstrated removal efficiencies of 64.2 ± 7.5% and 55.3 ± 19.2% for total chemical oxygen demand (COD) and total nitrogen, respectively, with an organic loading rate of 0.97 ± 0.03 kg-COD m-3day-1and a nitrogen loading rate of 0.57 ± 0.21 kg-N m-3day-1. 16S rRNA gene sequencing analysis of the sludge retained in the DHS also corresponded to the result of reactor performance, and both nitrifying and denitrifying bacteria were detected in the sponge carrier. In addition, anammox bacteria was found in the retained sludge. The DHS reactor reduced the HRT of 30 days to 4.8 h compared with the existing algal tank. This result indicates that the DHS reactor could be an appropriate post treatment for the existing anaerobic tank for natural rubber processing wastewater treatment.
authors.affiliation: Department of Civil and Environmental Systems Engineering, Nagaoka University of Technology, 1603-1, Kamitomioka, Nagaoka, Niigata 940-2188, Japan E-mail: ecoya@vos.nagaokaut.ac.jp; School of Chemical Engineering, Hanoi University of Science and Technology, No.1, Dai Co Viet, Hanoi, Vietnam.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Watari
authors.affiliation: Rubber Research Institute of Vietnam, Km42 Road 13, Ben Cat District, Binh Duong Province 827211, Vietnam.
authors.forename: Trung
authors.initials: T
authors.lastname: Cuong Mai
authors.affiliation: Department of Civil and Environmental Engineering, National Institute of Technology, Kure College, 2-2-11, Aga-minami, Kure, Hiroshima 737-8506, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Tanikawa
authors.affiliation: Department of Science of Technology Innovation, Nagaoka University of Technology, 1603-1, Kamitomioka, Nagaoka, Niigata 940-2188, Japan.
authors.forename: Yuga
authors.initials: Y
authors.lastname: Hirakata
authors.affiliation: Department of Civil and Environmental Systems Engineering, Nagaoka University of Technology, 1603-1, Kamitomioka, Nagaoka, Niigata 940-2188, Japan E-mail: ecoya@vos.nagaokaut.ac.jp.
authors.forename: Masashi
authors.initials: M
authors.lastname: Hatamoto
authors.affiliation: Center for Regional Environmental Research, National Institute for Environmental Studies, 16-2, Onogawa, Tsukuba, Ibaraki 305-8506, Japan.
authors.forename: Kazuaki
authors.initials: K
authors.lastname: Syutsubo
authors.affiliation: Department of Bioengineering, Nagaoka University of Technology, 1603-1, Kamitomioka, Nagaoka, Niigata 940-2188, Japan.
authors.forename: Masao
authors.initials: M
authors.lastname: Fukuda
authors.affiliation: Rubber Research Institute of Vietnam, Km42 Road 13, Ben Cat District, Binh Duong Province 827211, Vietnam.
authors.forename: Ngoc Bich
authors.initials: NB
authors.lastname: Nguyen
authors.affiliation: Department of Civil and Environmental Systems Engineering, Nagaoka University of Technology, 1603-1, Kamitomioka, Nagaoka, Niigata 940-2188, Japan E-mail: ecoya@vos.nagaokaut.ac.jp; Department of Science of Technology Innovation, Nagaoka University of Technology, 1603-1, Kamitomioka, Nagaoka, Niigata 940-2188, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Yamaguchi
mesh_terms: D000693:Anaerobiosis; D001419:Bacteria / Q000235:genetics / Q000378:metabolism; D019149:Bioreactors / Q000382:microbiology*; D007220:Industrial Waste / Q000032:analysis*; D058465:Nitrification; D009584:Nitrogen / Q000032:analysis; D012336:RNA, Ribosomal, 16S; D012408:Rubber / Q000737:chemistry*; D012722:Sewage / Q000382:microbiology; D014865:Waste Disposal, Fluid; D062065:Wastewater
chemical_list: D007220:Industrial Waste; D009584:Nitrogen; D012336:RNA, Ribosomal, 16S; D012408:Rubber; D012722:Sewage; D062065:Wastewater