Abstract:There are many ways of nitrogen transformation in wastewater treatment, among which dissimilatory nitrate reduction to ammonium (DNRA) convert NO3-/NO2- into NH4+, which is an important part of nitrogen transformation. This paper reviews the two-step reaction mechanism of DNRA process and microorganisms involved. In addition, the potential factors affecting the DNRA process in wastewater treatment, such as dissolved oxygen, types of carbon or nitrogen sources, C/N ratio, temperature, pH and special substances contained in wastewater, are emphatically discussed to explore how to regulate the competition between DNRA and denitrification. The application of quantitative functional genes and 15N tracing techniques provides technical support to better study the DNRA process. In general, this paper confirmed the occurrence and contribution of DNRA process in wastewater treatment, and the in-depth study of DNRA is of great significance for the removal or recovery of nitrogen in wastewater.