The metabolic strategy of phosphorus-accumulating organisms in response to low temperature in micro pressure swirl reactor

Abstract

The impact of low temperature on the growth and metabolism of phosphorus-accumulating organisms (PAO) is crucial for maintaining the stability of organic removal efficiency. To investigate how lowering the temperature affects PAO's metabolic strategy, a micro pressure swirl reactor (MPSR) was operated at temperatures of 15, 12, and 10℃. The interactions and metabolic pathways of the microbial community in the system were examined. The results showed total phosphorus (TP) removal rate efficiencies were 97.0 %, 94.0 %, and 94.8 % in 15, 12 and 10℃, respectively. As the temperature decreased, glycogen consumption decreased by 27.44 mg/gMLSS, while poly-β-hydroxybutyrate (PHB) accumulation and consumption increased by 33.80 and 37.88 mg/gMLSS, respectively. Two essential genera of PAO, Rhodocyclus, and Dechloromonas increased from 0.70 % and 0.31–3.04 % and 2.79 % respectively. The metabolism of PAO changed as the temperature decreased. Glycolysis was inhibited at temperatures 12 and 10℃, and PAO applied an increase in phosphorus metabolism to meet the energy requirements for growth metabolism. This conversion in metabolic strategy helped PAO gain a competitive advantage and ensured that MPSR maintained good phosphorus organic matter removal at low temperatures.