Nitrous oxide and methane production and consumption at five full-size denitrifying bioreactors treating subsurface drainage water

• DOI: 10.1016/j.scitotenv.2024.170956
• Publication Date: 2024-02-14T09:39:55Z
• Authors: Ann M. Brunton; Julie L. Zilles; Richard A. Cooke; Laura E. Christia...
• Keywords: Nitrous oxide; Subsurface Flow

Nitrate (NO3−) removal in denitrifying bioreactors is influenced by flow, water chemistry, and design, but it not known how these widely varying factors impact the production of nitrous oxide (N2O) or methane (CH4) across sites. Woodchip link hydrosphere atmosphere this respect, so five full-size Illinois, USA, were monitored for NO3−, N2O, CH4 to better document where treatment technology resides along pollution swapping climate smart spectrum. Both surface fluxes dissolved forms N2O measured (n = 7–11 sampling campaigns per site) at ranging from <1 nearly 5 years old treating subsurface drainage areas between 6.9 29 ha. Across all sites, volumetric rates averaged 1.0 ± 1.6 mg N2O-N/m3-d 24 62 dN2O-N/m3-d, respectively, 6.0 26 CH4-C/m3-d 310 520 dCH4-C/m3-d dissolved, respectively. However, was consistently consumed one bioreactor, only three sites produced notable CH4. Surface significantly reduced presence a soil cover. Bioreactor denitrification relatively efficient, with 0.51 3.5 % removed nitrate emitted as 48). Modeled indirect emissions lower when bioreactor present versus absent (EF5: 0.0055 0.0062 kg N2O-N/kg NO3-N; p 0.0011). While further greenhouse gas research on recommended, should be used an excuse slow adoption efforts. Bioreactors provide practical option voluntary quality improvement heavily tile-drained US Midwest elsewhere.