title: Enhanced denitrification in Downflow Hanging Sponge reactors for decentralised domestic wastewater treatment.
abstract: Enhanced aerobic/anoxic Downflow Hanging Sponge (DHS) bioreactors were assessed for carbon (C) and total nitrogen (TN) removal for decentralised domestic wastewater treatment applications. The initial design included upper aerobic and lower anoxic sponge layers, and effluent recirculation, and achieved >80% CODsand >90% NH4-N removal. However, effluent TN was higher. It was concluded the anoxic layer was C-limited for denitrification, therefore an influent bypass was added to the anoxic layer to provide supplemental C. Differed bypass ratios were compared, including 0%, 10%, 20% and 30% (% of total influent), and effluent TN declined with increasing bypass; i.e., 50.1±23.3mg-N/L, 49.9±27.8mg-N/L, 31.9±18.4mg-N/L and 10.7±5.8mg-N/L, respectively, and all reactors removed >80% CODs. This design has potential because it uses limited energy, tolerates variable flows, and simultaneously removes C and TN; all key for effective decentralised treatment applications.
authors.affiliation: School of Civil Engineering & Geosciences, Newcastle University, Newcastle upon Tyne, United Kingdom.
authors.forename: Catherine A
authors.initials: CA
authors.lastname: Bundy
authors.affiliation: School of Civil Engineering & Geosciences, Newcastle University, Newcastle upon Tyne, United Kingdom; Key Laboratory for Urban Ecological Processes and Eco-Restoration, School of Ecological and Environmental Science, East China Normal University, Shanghai, China.
authors.forename: Dong
authors.initials: D
authors.lastname: Wu
authors.affiliation: School of Civil Engineering & Geosciences, Newcastle University, Newcastle upon Tyne, United Kingdom.
authors.forename: Mui-Choo
authors.initials: MC
authors.lastname: Jong
authors.affiliation: School of Civil Engineering & Geosciences, Newcastle University, Newcastle upon Tyne, United Kingdom.
authors.forename: Stephen R
authors.initials: SR
authors.lastname: Edwards
authors.affiliation: Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology Delhi, Hauz Khas, New Delhi, India.
authors.forename: Ziauddin S
authors.initials: ZS
authors.lastname: Ahammad
authors.affiliation: School of Civil Engineering & Geosciences, Newcastle University, Newcastle upon Tyne, United Kingdom. Electronic address: david.graham@newcastle.ac.uk.
authors.forename: David W
authors.initials: DW
authors.lastname: Graham
mesh_terms: D000818:Animals; D057919:Biological Oxygen Demand Analysis; D019149:Bioreactors; D002244:Carbon / Q000032:analysis / Q000378:metabolism; D058440:Denitrification; D009584:Nitrogen / Q000032:analysis / Q000378:metabolism; D014865:Waste Disposal, Fluid / Q000295:instrumentation / Q000379:methods*; D062065:Wastewater / Q000737:chemistry
chemical_list: D002244:Carbon; D009584:Nitrogen; D062065:Wastewater
keywords: Bioreactors; Decentralised wastewater treatment; Denitrification; Sponge media; Waste bypass