Evaluation of Step Feeding Strategy in One-Stage Simultaneous Partial Nitritation, Anammox and Denitrification (SPNAD) Process

Fast start-up of simultaneous partial nitritation, anaerobic ammonium oxidation (anammox) and denitrification (SPNAD) process was achieved within a month by applying step feeding strategy without carbon source addition in the acclimation period. The decreasing cycle number of step feeding strategy successfully improved the SPNAD process performance and enhanced nitrogen and organic removal performance for treating sidestream wastewater. The 3-cycle step feeding strategy obtained higher average values of nitrogen loading rate (NLR), nitrogen removal rate (NRR), ammonium removal rate (ARR) and COD removal rate (CRR) of 0.50, 0.31, 0.45, and 0.18 kg/m3/day, respectively, than 10-cycle and 5-cycle step feeding strategy. The step feeding strategy also contributes in maintaining DO, pH and ORP sensors performance stability even after being operated in long-term duration.