A review of heavy metals inhibitory effects in the process of anaerobic ammonium oxidation

Anaerobic ammonium oxidation (anammox) is a promising biological technology for treating ammonium-rich wastewaters. However, due to the high sensitivity of anammox bacteria, many external factors have inhibitory effects on this process. As one of the commonly found toxic substances in wastewater, heavy metals (HMs) are possible to cause inhibition on anammox sludge, which then results in a declined treatment performance. Getting insights into the response mechanism of anammox sludge to HMs is meaningful for its application in treating this kind of wastewater. This review summarized the effect of different HMs on treatment performance of anammox bioreactor. In addition, the mechanism of toxication raised by HMs was discussed. Also, the potential mitigation strategies were summarized and the future prospects were outlooked. This review might provide useful information for both scientific research on and engineering application of anammox process for treating HMs containing wastewater.