Biological Phosphorus Removal Performance and Relevant Microorganism Characteristics of Activated Sludge in Municipal Wastewater Treatment Plants, China

Abstract

Municipal wastewater discharge is threatening the ecological security of the local water environment. This study investigated the field process performance and microorganism characteristics of enhanced biological phosphorus removal (EBPR) in municipal wastewater treatment plants (WWTPs) in China. The results showed that three WWTPs met the required criteria of phosphorus for discharge (≤1 mg/L), but with a low level of Accumulibacter (6.4 to 3.8%, on average) and a relatively high level of Competibacter (3.2 to 9.1%) in sludge. The phosphorus release and uptake rates were varied from 0.224 to 7.770 mg/gVSS·h and 0.386 to 7.901 mg/gVSS·h, respectively. Denitrifying polyphosphate‐accumulating organisms were estimated to be 28.2% of the polyphosphate‐accumulating organisms. Sludge characteristics (phosphorus release and uptake rates) were positively correlated with the abundance of Accumulibacter and negatively correlated with the proportion of Competibacter . Moreover, the lower the ratio of anaerobic phosphorus/acetate (e.g., 0.496) is, the more abundant the Competibacter would be. Further discussion on an improvement strategy for these WWTPs for EBPR should be comprehensively based on the data of periodic investigations on field operation, sludge activities, and microbial populations.