A novel single-stage process integrating simultaneous COD oxidation, partial nitritation-denitritation and anammox (SCONDA) for treating ammonia-rich organic wastewater.

In this study, simultaneous carbon oxidation, partial nitritation, denitritation and anammox (SCONDA) was successfully integrated into a one-stage sequencing biofilm batch reactor for treating ammonia-rich organic wastewater with carbon to nitrogen (C/N) ratio of 3. The results showed that 94.3% of COD removal together with 92.6% NH-N and 88% TN removal were achieved via SCONDA. High-throughout sequencing analysis further revealed that the microbial community developed in the proposed system was primarily dominated by heterotrophic bacteria (e.g. Thauera, Azovibrio, Ohtaekwangia, Azospira), autotrophic bacteria (e.g. Nitrosomona) and unclassified genus of anammox bacterium, which were all essential for COD and N removal via SCONDA. The observed spatial distributions of the functional species in stratified biofilms were found to be crucial for successful SCONDA at the low dissolved oxygen of 1.3 mg/L. The integrated SCONDA system is expected to offer a promising alternative for advanced nitrogen and organic removal from high-ammonia organic wastewater.