Cultivation of Anaerobic Ammonium Oxidation Bacteria and Their Performance in an Up-Flow Anaerobic Sludge Bed Reactor

Starting with a mixture of aerobic activated sludge and anaerobic sludge, effective anaerobic ammonia oxidation(ANAMMOX) mixed culture bacteria were prepared by enrichment and acclimation in a laboratory scale UASB(up-flow anaerobic sludge bed) reactor. For an influent containing both ammonia nitrogen(3~5 mmol/L) and nitrite nitrogen(4~6 mmol/L) and operating the reactor at loading rates of NH_3-N 2 mmol/(L·d) and NO_2-N 2.5 mmol/(L·d), as much as of 63% and 78% of NH_3-N and NO_2-N, respectively, were removed. The best treatment pH was 7.5, and the best temperature was 35(°C). The ANAMMOX rate increased with the concentration of NO_2-N up to 10 mmol/L and then decreased with still higher nitrite concentration in the reactor.