A practical study on the near-zero discharge of rainwater and the collaborative treatment and regeneration of rainwater and sewage

Yi Yang; Wenlong Bai; Defu Gan; Yuting Zhu; Xiaodi Li; Chengyu Liang; Siqing Xia

doi:10.1016/j.scitotenv.2024.173137

A practical study on the near-zero discharge of rainwater and the collaborative treatment and regeneration of rainwater and sewage

Sci Total Environ. 2024 May 11:934:173137. doi: 10.1016/j.scitotenv.2024.173137. Online ahead of print.

Authors

Yi Yang¹, Wenlong Bai², Defu Gan¹, Yuting Zhu³, Xiaodi Li¹, Chengyu Liang¹, Siqing Xia⁴

Affiliations

¹ State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China.
² Inner Mongolia Dongyuan Environmental Protection Technology Co., LTD, Inner Mongolia 014399, China.
³ Tongji Architectural Design (Group) Co., Ltd., Shanghai 200092, China.
⁴ State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China. Electronic address: siqingxia@gmail.com.

PMID: 38740207
DOI: 10.1016/j.scitotenv.2024.173137

Abstract

Non-conventional water recovery, recycling, and reuse have been considered imperative approaches to addressing water scarcity in China. The objective of this study was to evaluate the technical and economic feasibility of Water Reclamation Plants (WRP) based on an anaerobic-anoxic-oxic membrane bioreactor (A²O-MBR) system for unconventional water resource treatment and reuse in towns (domestic sewage and rainwater). Rainwater is collected and stored in the rainwater reservoir through the rainwater pipe network, and then transported to the WRP for treatment and reuse through the rainwater reuse pumping station during the peak water demand period. During a year of operation and evaluation process, a total of 610,000 cubic meters of rainwater were reused, accounting for 10.4 % of the treated wastewater. In the A²O-MBR operation, the average effluent concentrations for COD (chemical oxygen demand), NH₄⁺-N (ammonium), TN (total nitrogen), and TP (total phosphorus) were 14.23 ± 4.07 mg/L, 0.22 ± 0.26 mg/L, 11.97 ± 1.54 mg/L, and 0.13 ± 0.09 mg/L, respectively. The effluent quality met standards suitable for reuse in industrial cooling water or for direct discharge. The WRP demonstrates a positive financial outlook, with total capital and operating costs totaling 0.16 $/m³. A comprehensive cost-benefit analysis indicates a positive net present value for the WRP, and the estimated annualized net profit is 0.024 $/m³. This research has achieved near-zero discharge of wastewater and effective allocation of rainwater resources across time and space.

Keywords: A(2)O-MBR; Cost-benefit analysis; Efficient regeneration; Rainwater and sewage.