Enhanced biological phosphorus removal by high concentration powder carrier bio-fluidized bed (HPB): Phosphorus distribution, cyclone separation, and metagenomics.

This study provides a comparative investigation of phosphorus removal between anaerobic-anoxic-oxic (AAO) and high-concentration powder carrier bio-fluidized bed (HPB) in the same full-scale wastewater treatment plant. The results showed that the total phosphorus removal of HPB was 71.45%-96.71%. Compared with AAO, the total phosphorus removal of HPB can be increased by a maximum of 15.73%. The mechanisms of enhanced phosphorus removal by HPB include the followings. Biological phosphorus removal was significant. The anaerobic phosphorus release capacity of HPB was enhanced and polyphosphate (Poly-P) in the excess sludge of HPB was 1.5 times higher than that of AAO. The relative abundance of Candidatus Accumulibacter was 5 times higher than that of AAO, and oxidative phosphorylation and butanoate metabolism were enhanced. The analysis of phosphorus distribution showed that cyclone separation increased the chemical phosphorus precipitation (Chem-P) in the excess sludge by 16.96% to avoid accumulation in the biochemical tank. The phosphorus adsorbed by extracellular polymeric substance (EPS) in the recycled sludge was stripped, and the EPS bound-P in the excess sludge increased by 1.5 times. This study demonstrated the feasibility of HPB to improve the phosphorus removal efficiency for domestic wastewater.