Impacts of ammonium loading on nitritation stability and microbial community dynamics in the integrated fixed-film activated sludge sequencing batch reactor (IFAS-SBR)

摘要

This study investigates the impact of ammonium concentration on the establishment of partial nitrification microbial community in an integrated fixed-film activated sludge (IFAS) reactor. Partial nitrification was achieved successfully under room temperature when the NH4+-N concentration in the feeding was greater than 400 mg/L. Molecular analysis confirmed that ammonia oxidizing bacteria (AOB) abundance increased and nitrite oxidizing bacteria (NOB) number reduced at high ammonium loading conditions. Compared with biofilm, suspended sludge played a major role in ammonium removal, which contributed to 66% total ammonium removal. Biosorption and biodegradation were found to be the two main mechanisms for ammonium removal in the WAS system.