Efficient and integrated start-up strategy for partialnitrification to nitrite treating low C/N domestic wastewater

摘要

Nitrogen removal via the nitrite pathway has the potential of reducing the requirements fornaeration consumption and carbon source. However, the development of an efficient and quicknstart-up strategy for partial nitrification to nitrite has proven difficult in the treatment of lownstrength wastewater. In this study, the feasibility of partial nitrification achieved by usingnreal-time aeration duration control was not only demonstrated from the kinetic mechanism,nbut also was validated in three sequencing batch reactors (SBRs) fed with low C/N domesticnwastewater. Nitrite accumulation could be achieved when aeration was terminated as soon asnan inflexion pH point was reached (the dpH/dt became from negative to positive).nThe reduction or limitation of the NOB growth could be achieved through aeration durationncontrol, due to leaving no extra time for NOB to convert the accumulated nitrite.nThe experimental operation results also showed that partial nitrification with nitritenaccumulation ratios of over 80% was achieved successfully in these three reactors withnprocess control. Fluorescence in situ hybridization (FISH) analysis indicated the reduction ofnNOB was achieved and AOB became the dominant nitrifying bacteria. Moreover, an integratednstart-up strategy based on aeration duration control was proposed to quickly achieve partialnnitrification to nitrite.