Mitigation of Greenhouse Gas Emission during Nitrite-dependent Methane Anaerobic Oxidation Process by Increasing Static Pressure

Abstract

Nitrite-dependent anaerobic methane oxidation (n-damo) process is a novel wastewater treatment technology, but the greenhouse gas (GHG) emission during the process is lack of report. N-damo bacteria was enriched and the GHG emission during n-damo process was measured in this study, and the feasibility of GHG emission mitigation by increasing static pressure was also investigated. Both reactors in this study obtained high efficiencies of nitrite removal which were 5.92 mg N L-1 d-1 g-1and 7.49 mg N L-1 d-1 g-1, respectively, the nitrite removal rate in reactor under static pressure was improved 26.52% than reactor under ambient pressure. With similar N2O emission, lower total global warming potential (GWP) in reactor under static pressure was obtained because improved n-damo process led to the higher CH4 sink. According to microbial analysis, improved n-damo process was resulted from higher abundance of n-damo bacteria in reactor under static pressure. Furthermore, static pressure could enhance the screening of non-target bacteria such as denitrifying bacteria and make n-damo bacteria predominate and further enhance n-damo process.