Generation, emission reduction/utilization, and challenges of greenhouse gas nitrous oxide in wastewater treatment plants – A review

Abstract

In recent years, more and more papers have confirmed that nitrous oxide (N2O) is an important byproduct of wastewater treatment plants (WWTPs). On a global scale, massive production, and atmospheric emission of N2O would exacerbate the runaway greenhouse effect. There are currently two possible approaches to dealing with N2O produced in WWTPs. On the one hand, by adjusting the process operating conditions or adopting physical and chemical measures, the production of N2O in WWTPs may be reduced, but not necessarily eliminated. Conversely, by optimizing WWTP processes to promote N2O production, the N2O produced by WWTPs could be captured and used in the production of industrial or medical raw materials. Combining a review of recent studies with the conclusions and opinions of the authors, this paper outlines some opportunities and challenges to deal with the production of N2O in WWTPs, focusing on production, emissions reduction, and resource utilization. Some suggestions for emission reduction and/or resource utilization of N2O are put forward for WWTPs with different N2O production levels, which could provide simple, feasible, and economical methods for the design construction and operation of WWTPs in the future.