A2O-MBR as an efficient and profitable unconventional water treatment and reuse technology: A practical study in a green building residential community

Abstract

Unconventional water reclamation, recycling, and reuse have been identified as the major approaches for addressing water scarcity in China. The aim 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 (domestic wastewater and rainwater) treatment and reuse in green building residential community. During a year operation and evaluation process, average chemical oxygen demand (COD), biochemical oxygen demand (BOD5), total nitrogen (TN) and total phosphorus (TP) removal efficiencies averaged 83.7 ± 3.2%, 91.6 ± 2.6%, 69.0 ± 6.5% and 74.5 ± 5.5%, respectively. The effluent quality of wastewater treated by the A2O-MBR system complied with the water quality standards for reuse for green building residential community or for direct discharge. Typical seasonal fluctuations of temperature, COD loading rate, BOD5/COD and COD/TN were the key factors affecting pollutants removal efficiencies, and the membrane fouling rate was accelerated at low temperatures. The total cost of capital and operation was 0.406 $/m3, a cost-benefit analysis incorporating both capital and operating expenditures showed that more than 60% of the reclaimed water is reused in the green building, and the full-scale WRP exhibits a positive net present value. These results demonstrated that A2O-MBR is an efficient and profitable technology for nontraditional water resource recycling in green building residential communities in terms of technical and economic feasibility.