Effect of return activated sludge diversion ratio on phosphorus removal performance in side-stream enhanced biological phosphorus removal (S2EBPR) process

Taotao Lv; Dongqi Wang; Jiayao Hui; Wen Cheng; Hao Ai; Lu Qin; Mengbo Huang; Minquan Feng; Yufan Wu

doi:10.1016/j.envres.2023.116546

Effect of return activated sludge diversion ratio on phosphorus removal performance in side-stream enhanced biological phosphorus removal (S2EBPR) process

Environ Res. 2023 Oct 15:235:116546. doi: 10.1016/j.envres.2023.116546. Epub 2023 Jul 3.

Authors

Taotao Lv¹, Dongqi Wang², Jiayao Hui³, Wen Cheng¹, Hao Ai⁴, Lu Qin³, Mengbo Huang³, Minquan Feng⁵, Yufan Wu³

Affiliations

¹ State Key Laboratory of Eco-Hydraulics in Northwest Arid Region, Xi'an University of Technology, Xi'an, Shaanxi, 710048, China; Department of Municipal and Environmental Engineering, School of Water Resources and Hydro-Electric Engineering, Xi'an University of Technology, Xi'an, Shaanxi, 710048, China.
² State Key Laboratory of Eco-Hydraulics in Northwest Arid Region, Xi'an University of Technology, Xi'an, Shaanxi, 710048, China; Department of Municipal and Environmental Engineering, School of Water Resources and Hydro-Electric Engineering, Xi'an University of Technology, Xi'an, Shaanxi, 710048, China; Shaanxi Key Laboratory of Water Resources and Environment, Xi'an University of Technology, Xi'an, Shaanxi, 710048, China. Electronic address: wangdq@xaut.edu.cn.
³ Department of Municipal and Environmental Engineering, School of Water Resources and Hydro-Electric Engineering, Xi'an University of Technology, Xi'an, Shaanxi, 710048, China.
⁴ Shaanxi Provincial Geological Survey Experiment Center, Shaanxi Institute of Geological Survey, Xi'an, Shaanxi, 710065, China.
⁵ State Key Laboratory of Eco-Hydraulics in Northwest Arid Region, Xi'an University of Technology, Xi'an, Shaanxi, 710048, China; Department of Municipal and Environmental Engineering, School of Water Resources and Hydro-Electric Engineering, Xi'an University of Technology, Xi'an, Shaanxi, 710048, China; Shaanxi Key Laboratory of Water Resources and Environment, Xi'an University of Technology, Xi'an, Shaanxi, 710048, China. Electronic address: mqfeng@xaut.edu.cn.

PMID: 37406718
DOI: 10.1016/j.envres.2023.116546

Abstract

In this study, a lab-scale continuous flow side-stream enhanced biological phosphorus (P) removal (S2EBPR) reactor was operated for 247 days treating synthetic wastewater with influent carbon to phosphorus (C/P) ratio of 25.0 g COD/g P and influent PO₄^3--P of 7.4 ± 0.3 mg P/L. The effect of the return activated sludge (RAS) diversion ratio on S2EBPR reactor was investigated by comparing P removal performance, microbial activity, and community structure. The results showed that the RAS diversion ratio of 8.0%, by yielding a side-stream sludge retention time (SRT_SS) of ∼60 h, resulted in the lowest effluent PO₄^3--P concentration of 0.5 ± 0.3 mg P/L. The results of in situ process profiles and ex situ P release and uptake batch tests under different RAS diversion conditions showed that the more anaerobic P release was obtained in the side-stream reactor, the higher the P removal efficiency and EBPR activity were achieved. The stoichiometric ratios observed in EBPR activity tests indicated a polyphosphate accumulating organisms (PAOs) metabolism mainly dependent on the glycolysis pathway. The results of microbial ecology analysis revealed that the optimized SRT_SS would give a competitive advantage to PAOs in the S2EBPR process. By obtaining statistically reliable results, this study would provide guidance for wastewater treatment plants to achieve optimal P removal performance in S2EBPR configuration.

Keywords: EBPR; Glycolysis pathway; PAO; Phosphorus removal performance; RAS diversion ratio; Side-stream.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Bioreactors
Carbon
Phosphorus*
Sewage*
Wastewater

Substances

Sewage
Phosphorus
Wastewater
Carbon