Abstract
Energy and resource-saving technologies for wastewater treatment have been required. A partial nitrification-ANAMMOX process is one of the efficient processes for the nitrogen removal, however, promising operational methods for partial nitrification is required for stable and effective denitrification by ANAMMOX. The objective of this study is to comprehend effects of SRT on water quality and microbial community in reactors for partial nitrification. It was achieved that nitrite accumulated over 50% of total nitrogen for 15 days in a reactor with SRT of 3.4 days but not achieved with other SRT conditions. Therefore, it was shown that a SRT control can be useful for the partial nitrification. It was likely that amounts of AOB and NOB affect the partial nitrification because the transition of their amount changed when nitrite started to accumulate. When nitrate concentrations started to increase, changes in bacterial mass of AOB and NOB were observed. It was also cleared that the differences of SRT affected microbial community in each reactor, and comparable results of microbial community formation were obtained when the SRT condition is similar, which suggests operation by SRT can control microbial community formation in nitrifying reactor.
