Low loading wastewater treatment and reuse by A²/O-MBR process

A²/O-MBR combined process was developed for campus wastewater treatment and reuse with the treatment capability of 2 000 m³/d. Water quality analysis was conducted during steady operation period, and the experimental results indicated that the A²/O-MBR combined process showed good performance in campus wastewater treatment. Though the influent concentrations of COD, NH₄⁺-N, TN and TP were in the range of 100~200 mg/L, 19~33 mg/L, 25~43 mg/L and 3~5 mg/L, respectively, and the C/N ratio of influent was very low, the effluent quality was superior to the requirements of Water Quality Standard for Urban Miscellaneous Water Consumption (GB 18920-2002). All the effluent was reused for toilet flushing, gardening, and so on. By running cost analysis, it was found that the running cost of this combined process was about 0.96 yuan/m³ and each year about 730 000 tons of drinking water could be saved. The system brought excellent environmental and economic benefits.