A novel denitrifying phosphorus removal and partial nitrification, anammox (DPR-PNA) process for advanced nutrients removal from high-strength wastewater

Abstract

This study developed a novel DPR-PNA (denitrifying phosphorus removal, partial nitrification and anammox) process for sustaining high-strength wastewater treatment in a modified continuous flow reactor without external carbon source. After 259-days operation, a synchronous highly-efficient total inorganic nitrogen, PO43--P and CODcr removal efficiencies of 88.5%, 89.5% and 90.1% were obtained, respectively even influent nitrogen loading rate up to 3.2 kg m−3 d−1. Batch tests revealed that denitrifying phosphorus accumulating organisms (DPAOs) using NO3−-N as electron acceptors significantly enriched (74% in total PAOs), which emerged remarkable positive impacts on deep-level nutrient removal as the key limiting factor. Furthermore, the NO2−-N inhibitory threshold value (∼20.0 mg L−1) for DPAOs was identified, which demonstrated as an inhibitory component in excessive recycling NOx−-N. From the molecular biology perspective, Dechloromonas-DPAOs group (18.59%) dominated the excellent dephosphatation performance, while Nitrosomonas-AOB (ammonia oxidizing bacteria) group (16.26%) and Candidatus_Brocadia-AnAOB (anammox bacteria) group (15.12%) were responsible for the desirable nitrogen loss process. Overall, the present work highlighted the novel DPR-PNA process for nutrients removal is a promising alternation for wastewater of high nitrogen but low carbon.