Research Progress,Problems and Future Prospects of A New Combined Anaerobic Ammonia Oxidation and Nitrogen Removal Process

Anaerobic ammonium oxidation (Anammox) is a cost-effective and efficient process for nitrogen removal, which has attracted widespread attention in the field of wastewater treatment due to its significant advantages. However, the slow rate of growth of anaerobic ammonium oxidizing bacteria (AnAOB) and its sensitivity to operational and environmental conditions hinder its wide application. Although various control strategies have been explored and developed, the application of Anammox process still faces many challenges, including unstable nitrogen removal performance and the necessity for additional treatment of effluent nitrate nitrogen. Due to the importance and necessity of Anammox in wastewater denitrification, this paper first introduces the present biological denitrification system based on Anammo. In view of the insufficient source of nitrite nitrogen in nitrogen-containing wastewater, nitrite nitrogen can be provided by partial nitrification (PN) or partial denitrification (PD) , however, the stability of system operation and efficiency of denitrification are still the difficulties in Anammox engineering applications. It is especially crucial to study the combined new processes based on Anammox to achieve stable deep biological nitrogen removal from wastewater. Therefore, this paper focuses on latest research progress in Anammox coupled simultaneous partial nitrification, denitrification and anammox (SPNDA) , constructed wetland (CW) , phosphorus removal/ recovery process, sulfur denitrification removal (SDA) and denitrifying anaerobic methane oxidation (ADAMO) . The nitrogen removal performance, influencing factors, operation advantages, research progress, application prospects and challenges are reviewed. Compared with the single Anammox process, the combined process offers several advantages, including overcoming the issue of nitrate in the effluent (SPNDA, A-DAMO, SDA) , alleviate the inhibition of organic matter on AnAOB (SPNDA, SDA) , recover non-renewable resources (HAP) , and achieve a clean environment with significant economic benefits (A-CW) , providing flexibility for the promotion and application of Anammox process. The study outlines future directionsfor researching, developing, and applying the Anammox combined nitrogen removal process, and at the same time provides as a reference for lowering energy consumption, achieving efficient and stable nitrogen removal processes, and broadensing the scope of engineering application.