Development of a novel denitrifying phosphorus removal and partial denitrification anammox (DPR plus PDA) process for advanced nitrogen and phosphorus removal from domestic and nitrate wastewaters

A novel energy-efficient DPR + PDA (denitrifying phosphorus removal and partial denitrification anammox) process for enhanced nitrogen and phosphorus removal was developed in the combined ABR-CSTR reactor. After 220 days operation, excellent total inorganic nitrogen (TIN) and phosphorus removal (97.57% and 95.66%, respectively) were obtained under external C/NO3? -N of 0.7, with the effluent TIN and PO43? -P concentrations of 3.51 mg/L and 0.28 mg/L, respectively. At the steady period, DPR contributed major TN removal (58.65%), while PDA mediated an increasingly considerable impact and finally achieved 37.07%, in which anammox accounted for a significant percentage. Batch tests demonstrated that efficient PD with nitrate-to-nitrite transformation ratio of 97.67% supplying stable nitrite for anammox, and phosphorus was mainly removed using nitrate as electron acceptor via DPR with the ideal phosphorus release/uptake rate (7.73/22.17 mgP/gVSS/h).

Automated summary

A novel energy-efficient DPR + PDA process was developed for enhanced nitrogen and phosphorus removal in the combined ABR-CSTR reactor. DPR contributed major TN removal, while PDA and anammox also played important roles in TP removal.