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Enhanced denitrification in Downflow Hanging Sponge reactors for decentralised domestic wastewater treatment

Lookup NU author(s): Florence Jong, Stephen Edwards, Professor David GrahamORCiD



This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).


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% CODs and >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 ± 23.3 mg-N/L, 49.9 ± 27.8 mg-N/L, 31.9 ± 18.4 mg-N/L and 10.7 ± 5.8 mg-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.

Publication metadata

Author(s): Bundy CA, Wu D, Jong M-C, Edwards SR, Ahammad ZS, Graham DW

Publication type: Article

Publication status: Published

Journal: Bioresource Technology

Year: 2017

Volume: 226

Pages: 1-8

Print publication date: 01/02/2017

Online publication date: 02/12/2016

Acceptance date: 30/11/2016

Date deposited: 12/12/2016

ISSN (print): 0960-8524

ISSN (electronic): 1873-2976

Publisher: Elsevier


DOI: 10.1016/j.biortech.2016.11.12

PubMed id: 27951508


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