Quantitative and qualitative effects of bioaugmentation on ammonia oxidisers at a two-step WWTP

摘要

Large waste water treatment plants (WWTP) often operate nitrification in two different processnenvironments: the cold-dilute sewage is treated in the mainstream nitrification/denitrificationnsystem, while the high strength ammonia liquors from sludge dewatering are treated in anseparate high temperature reactor (SBR). This study investigates transfer from nitrifier biomassninto a two-stage WWTP, commonly referred to as bioaugmentation. Besides the quantitation ofnammonia oxidising bacteria (AOB), community differences were analysed with two techniques,ndenaturing gradient gel electrophoresis and real-time PCR melt curve analysis. It was shown that,nwithout bioaugmentation, two distinct AOB communities establish in the mainstream and in thenSBR, respectively. A gradual shift of the two AOB communities with increasing pump ratesnbetween the systems could be demonstrated. These molecular findings support processnengineering experience, that cycling of waste activated sludge improves the ability of AOB tonadapt to different process environments.