Insights into Nitrous Oxide Mitigation Strategies in Wastewater Treatment and Challenges for Wider Implementation

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review

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Author(s)

  • Haoran Duan
  • Yingfen Zhao
  • Konrad Koch
  • George F. Wells
  • Min Zheng
  • Liu Ye

Detail(s)

Original languageEnglish
Pages (from-to)7208-7224
Journal / PublicationEnvironmental Science and Technology
Volume55
Issue number11
Online published12 May 2021
Publication statusPublished - 1 Jun 2021
Externally publishedYes

Abstract

Nitrous oxide (N2O) emissions account for the majority of the carbon footprint of wastewater treatment plants (WWTPs). Many N2O mitigation strategies have since been developed while a holistic view is still missing. This article reviews the state-of-the-art of N2O mitigation studies in wastewater treatment. Through analyzing existing studies, this article presents the essential knowledge to guide N2O mitigations, and the logics behind mitigation strategies. In practice, mitigations are mainly carried out by aeration control, feed scheme optimization, and process optimization. Despite increasingly more studies, real implementation remains rare, which is a combined result of unclear climate change policies/incentives, as well as technical challenges. Five critical technical challenges, as well as opportunities, of N2O mitigations were identified. It is proposed that (i) quantification methods for overall N2O emissions and pathway contributions need improvement; (ii) a reliable while straightforward mathematical model is required to quantify benefits and compare mitigation strategies; (iii) tailored risk assessment needs to be conducted for WWTPs, in which more long-term full-scale trials of N2O mitigation are urgently needed to enable robust assessments of the resulting operational costs and impact on nutrient removal performance; (iv) current mitigation strategies focus on centralized WWTPs, more investigations are warranted for decentralised systems, especially decentralized activated sludge WWTPs; and (v) N2O may be mitigated by adopting novel strategies promoting N2O reduction denitrification or microorganisms that emit less N2O. Overall, we conclude N2O mitigation research is reaching a maturity while challenges still exist for a wider implementation, especially in relation to the reliability of N2O mitigation strategies and potential risks to nutrient removal performances of WWTPs. © 2021 American Chemical Society

Research Area(s)

  • challenges, greenhouse gas, mitigation, nitrogen removal, nitrous oxide, perspectives

Citation Format(s)

Insights into Nitrous Oxide Mitigation Strategies in Wastewater Treatment and Challenges for Wider Implementation. / Duan, Haoran; Zhao, Yingfen; Koch, Konrad et al.
In: Environmental Science and Technology, Vol. 55, No. 11, 01.06.2021, p. 7208-7224.

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review