Simultaneous Short-Cut Nitrification-Denitrification Phosphorus Removal Granules Induced by Phosphorus Removal Granules

Abstract

This paper investigated domestic sewage with a low C/N ratio. Mature phosphorus removal granules were inoculated to cultivate granules with a simultaneous short-cut nitrification and denitrification function. The characteristics of nitrogen and phosphorus removal of this process were analyzed. Results show that AOB can be enriched by prolonging the sludge age for 30 days with an aeration intensity of 5 L·(h·L)-1 and shorter aeration time (140 min), whereas the simultaneous nitrification and denitrification ability could not be improved. The nitrogen loss increased at the aerobic time when aeration intensity was reduced by 3.5 L·(h·L)-1 and aeration time was prolonged by 200 min. The aeration time was further optimized to restrain the transformation of NO2- to NO3-, and finally the effluent of TP < 0.5 mg·L-1 and TN < 15 mg·L-1. During the process of the system function transformation from phosphorus removal to nitrogen and phosphorus removal, the phosphorus release decreased, however PAOs still played a dominant role (60%) in the process of internal carbon storage. Batch experiments showed that DPAOs that can utilize nitrite as an electron acceptor accounts for 52.43% in the total PAOS, which alleviated the pressure of the carbon source and improved the simultaneous nitrogen and phosphorus removal.