Startup of a Partial Nitritation-Anammox MBBR and the Implementation of pH-Based Aeration Control

: The single-stage deammonification moving bed biofilm reactor (MBBR) is a process for treating high strength nitrogen waste streams. In this process, partial nitritation and anaerobic ammonia oxidation (anammox) occur simultaneously within a biofilm attached to plastic carriers. An existing tank at the James River Treatment Plant (76 ML/d) in Newport News, Virginia was modified to install a sidestream deammonification MBBR process. This was the second sidestream deammonification process in North America and the first MBBR type installation. After 4 months the process achieved greater than 85% ammonia removal at the design loading rate of 2.4 g /m2·d (256 kg /d) signaling the end of startup. Based on observations during startup and process optimization phases, a novel pH-based control system was developed that maximizes ammonium removal and results in stable aeration and effluent alkalinity.