(238b) Granulation of Anammox Sludge in Upflow Reactors

Anammox process is a promising biological nitrogen removal (BNR) technology for treatment of ammonium‒rich wastewater. A great challenge for the Anammox process is that chemolithoautotrophic Anammox bacteria exhibit a slow initial growth rate, resulting in poor enrichment of Anammox biomass. Granulation of the Anammox sludge has shown to effectively enhance the biomass enrichment. Anammox bacteria secrete a large amount of extracellular polymeric substances (EPS) and contain plentiful hydrophobic functional groups that facilitate the biomass granulation. Granulation enhanced the sludge settling property and retention time, which contributes to the high nitrogen removal rate (NRR) and stable operation of Anammox upflow reactors. The presentation comprehensively reviews the granulation of Anammox biomass, including characteristics of Anammox bacteria, formation of Anammox granules, and physicochemical and microbial properties of granules. Operational conditions and related BNR mechanisms were also discussed to optimize the performance of Anammox upflow reactors. Finally, full‒scale applications of Anammox granular sludge were presented. This review sheds light on the enhanced nitrogen removal from wastewaters by Anammox granules.