Development of Long Term Preservation and Re-Activation Techniques for ANAMMOX Bacteria.

ANAMMOX are slow growing biofilm-forming bacteria responsible for the anaerobic oxidation of ammonia to produce nitrogen gas and nitrate according to the reaction: NH₄⁺ + 1.32 NO₂^- → 1.02 N₂ + 0.26 NO₃^- + 2 H₂O. ANAMMOX-based bioreactors are being used to effectively treat high ammonia concentrations in industrial, municipal and agricultural wastewaters. Usually, fresh sludge is needed to start a new bioreactor because long-term storage and reactivation of ANAMMOX sludge is difficult. Currently, there is a paucity of methods for long-term preserving and quickly re-activating ANAMMOX bacteria. The objective of our research was to compare a variety of preservation methods on freshly collected ANAMMOX and test sludge reactivation after storage. Several different techniques will be presented for preservation and potential long-term storage of ANAMMOX sludge samples for later use as “seed” inocula for new bioreactors.