Differential impacts of rain event and continuous rainfall on biological phosphorus removal of a full-scale wastewater treatment plant: performance analysis and optimization strategies

Jiaming Hu; Lu-Man Jiang; Lihua Wang; Xinya Ding; Xinhong Han; Yan Zhang; Haijuan Wei; Zhan Qiu; Ying An; Zhen Zhou

doi:10.1016/j.jenvman.2025.126385

Differential impacts of rain event and continuous rainfall on biological phosphorus removal of a full-scale wastewater treatment plant: performance analysis and optimization strategies

J Environ Manage. 2025 Jun 26:390:126385. doi: 10.1016/j.jenvman.2025.126385. Online ahead of print.

Authors

Jiaming Hu¹, Lu-Man Jiang¹, Lihua Wang², Xinya Ding¹, Xinhong Han¹, Yan Zhang², Haijuan Wei², Zhan Qiu², Ying An¹, Zhen Zhou³

Affiliations

¹ Shanghai Engineering Research Center of Energy - Saving in Heat Exchange Systems, College of Environmental and Chemical Engineering, Shanghai University of Electric Power, Shanghai, 200090, China.
² Shanghai Chengtou Wastewater Treatment Co., Ltd, Shanghai, 201203, China.
³ Shanghai Engineering Research Center of Energy - Saving in Heat Exchange Systems, College of Environmental and Chemical Engineering, Shanghai University of Electric Power, Shanghai, 200090, China; School of Ecological and Environmental Sciences, East China Normal University, Shanghai, 200241, China. Electronic address: zzhou@des.ecnu.edu.cn.

PMID: 40577870
DOI: 10.1016/j.jenvman.2025.126385

Abstract

This study classified wet weather into rain event and continuous rainfall, focusing on the impact of continuous rainfall on enhanced biological phosphorus removal (EBPR) efficiency in a full-scale wastewater treatment plant. During rain event and continuous rainfall, influent COD concentrations was reduced by 7.9 % and 11.4 %, but effluent COD, ammonium nitrogen and total nitrogen remained below discharge limits. Compared to rain event, continuous rainfall significantly deteriorated EBPR performance and disturbed phosphorus metabolism. Continuous rainfall resulted in a negative difference between phosphorus uptake and release, depletion of poly-β-hydroxyalkanoates pools under aerobic conditions, and decreased relative abundance of phosphorus-accumulating organisms, norank_f__PHOS-HE36 and norank_f__Caldilineaceae. Simulation results indicated that new strategy of shortening aerobic hydraulic retention time and decreasing sludge recirculation ratios improved EBPR efficiency by 76.0 % and reduced treatment cost by 28.1 % during continuous rainfall. Overall, this study highlights that continuous rainfall has more severe impairment to EBPR than rain event, and provides effective strategy to alleviate it.

Keywords: Anaerobic/anoxic/aerobic (AAO) process; Continuous rainfall; Enhancing biological phosphorus removal (EBPR); Model; Wastewater treatment plant; Wet weather.