title: Unravelling the spatial variation of nitrous oxide emissions from a step-feed plug-flow full scale wastewater treatment plant.
abstract: Plug-flow activated sludge reactors (ASR) that are step-feed with wastewater are widely adopted in wastewater treatment plants (WWTPs) due to their ability to maximise the use of the organic carbon in wastewater for denitrification. Nitrous oxide (N2O) emissions are expected to vary along these reactors due to pronounced spatial variations in both biomass and substrate concentrations. However, to date, no detailed studies have characterised the impact of the step-feed configuration on emission variability. Here we report on the results from a comprehensive online N2O monitoring campaign, which used multiple gas collection hoods to simultaneously measure emission along the length of a full-scale, step-fed, plug-flow ASR in Australia. The measured N2O fluxes exhibited strong spatial-temporal variation along the reactor path. The step-feed configuration had a substantial influence on the N2O emissions, where the N2O emission factors in sections following the first and second step feed were 0.68% ± 0.09% and 3.5% ± 0.49% of the nitrogen load applied to each section. The relatively high biomass-specific nitrogen loading rate in the second section of the reactor was most likely cause of the high emissions from this section.
authors: Advanced Wastewater Management Centre, The University of Queensland, St. Lucia, QLD, Australia.|Department of Environmental Science and Engineering, School of Architecture and Environment, Sichuan University, Chengdu, Sichuan 610065, China.
authors: Yuting
authors: Y
authors: Pan
authors: Australian Water Quality Centre, Adelaide, 5000, South Australia, Australia.|Health and Environment Group, School of the Environment, Flinders University, Bedford Park, 5042, South Australia, Australia.|Centre for Water Management and Reuse, School of Natural and Built Environments, University of South Australia, Mawson Lakes, 5095, South Australia, Australia.
authors: Ben
authors: B
authors: van den Akker
authors: Advanced Wastewater Management Centre, The University of Queensland, St. Lucia, QLD, Australia.|School of Chemical Engineering, The University of Queensland, St. Lucia, Brisbane, QLD, 4072, Australia.
authors: Liu
authors: L
authors: Ye
authors: Advanced Wastewater Management Centre, The University of Queensland, St. Lucia, QLD, Australia.
authors: Bing-Jie
authors: BJ
authors: Ni
authors: Advanced Wastewater Management Centre, The University of Queensland, St. Lucia, QLD, Australia.
authors: Shane
authors: S
authors: Watts
authors: Australian Water Quality Centre, Adelaide, 5000, South Australia, Australia.
authors: Katherine
authors: K
authors: Reid
authors: Advanced Wastewater Management Centre, The University of Queensland, St. Lucia, QLD, Australia.
authors: Zhiguo
authors: Z
authors: Yuan
mesh_terms: D000393:Air Pollutants / Q000032:analysis; D018712:Analgesics, Non-Narcotic / Q000032:analysis*; D001315:Australia; D019149:Bioreactors / Q000382:microbiology*; D009584:Nitrogen / Q000378:metabolism; D009609:Nitrous Oxide / Q000032:analysis*; D012722:Sewage / Q000382:microbiology; D062211:Spatio-Temporal Analysis; D062065:Wastewater; D018508:Water Purification
chemical_list: D000393:Air Pollutants; D018712:Analgesics, Non-Narcotic; D009584:Nitrogen; D009609:Nitrous Oxide; D012722:Sewage; D062065:Wastewater