How does high C load affect nitrous oxide emission of subsurface wastewater infiltration system?

Ying-Hua Li; Hai-Bo Li; Lei Yang; Siqi Wang; Fei Su; Xin-Yang Xu

doi:10.1016/j.scitotenv.2019.134174

How does high C load affect nitrous oxide emission of subsurface wastewater infiltration system?

Sci Total Environ. 2020 Jan 1:698:134174. doi: 10.1016/j.scitotenv.2019.134174. Epub 2019 Aug 28.

Authors

Ying-Hua Li¹, Hai-Bo Li², Lei Yang¹, Siqi Wang¹, Fei Su¹, Xin-Yang Xu¹

Affiliations

¹ School of Resources and Civil Engineering, Northeastern University, Shenyang, China.
² School of Resources and Civil Engineering, Northeastern University, Shenyang, China. Electronic address: graceli_2003@163.com.

PMID: 31499346
DOI: 10.1016/j.scitotenv.2019.134174

Abstract

Subsurface wastewater infiltration systems (SWISs) have drawn much attention due to the lower operating costs, lower energy demands and absence of secondary pollutants requiring further treatment. The process of denitrification involves reduction of nitrate to nitrous oxide (N₂O) and dinitrogen gas (N₂). Though removal of nitrate is advantageous from a water quality perspective, N₂O may contribute to adverse environmental effects. This study evaluated N₂O emission at high C loading regimes. The results revealed that as the C load increased, N₂O emission increased first and then decreased, indicating that carbon source was a limiting factor for the release of N₂O from the denitrification process. Denitrification was the dominant process for the release of N₂O at any of the given C loads. When the influent carbon load was in the range of 220-460 mg/L, the contribution of denitrification to N₂O emissions came to 69.77-83.11% (feeding period) and 67.07-79.53% (rest period), respectively.

Keywords: C load; Emission rate; Nitrous oxide; Subsurface wastewater infiltration.