Integrated anaerobic ammonium oxidization with partial denitrification process for advanced nitrogen removal from high-strength wastewater

In this study, a novel integrated anaerobic ammonium oxidization with partial denitrification process (termed as ANAMMOX-PD) was developed for advanced nitrogen removal from high-strength wastewater, which excess NO₃⁻-N produced by ANAMMOX was fed into PD reactor for NO₂⁻-N production and then refluxing to ANAMMOX reactor for further removal. Results showed that total nitrogen (TN) removal efficiency as high as 97.8% was achieved and effluent TN-N was below 20 mg/L at influent TN-N of 820 mg/L. Furthermore, the feasibility of simultaneously treating domestic wastewater was demonstrated in ANAMMOX-PD process, and NH₄⁺-N removal efficiency of 96.7% was obtained. The nitrogen removal was mainly carried out through ANAMMOX pathway, and high-throughput sequencing revealed that Candidatus_Brocadia was the major ANAMMOX species. The presented process could effectively solve the problem of excess nitrate residual in ANAMMOX effluent, which hold a great potential in application of currently ANAMMOX treating high-strength wastewater (e.g. sludge digestion supernatant).