Groundwater Risk Management During Reclaimed Water Project At Shunyi Segment Of Chaobai River

Reclaimed water reuse as an effective way solving water shortage and water contamination has been payed more attention worldwide. It is required in China, especially in the northern area with a desperate shortage of water. Beijing features a dense population and a lack of water resource with an average per capital amount less than 300 m3, only about 1/8 of the national per capital amount. The quality of reclaimed water from advanced treatment of wastewater treatment plant is stable, which not only saves water resource but also alleviates wastewater discharge pressure. In recent years, reuse of reclaimed water has been developed rapidly.Chaobai River is of great strategic position in Beijing urban development. Reclaimed water from Wenyu River treated with MBR has been discharged to Shunyi segment of Chaobai River to recover ecological water of Chaobai River and to improve the water quality surrounding the Olympic stadium and the new Shunyi Town.The main purpose of this research was to analyze the water quality safety risk of the reclaimed water which was discharged to Shunyi segment of Chaobai River for groundwater supplement. However, the trace contaminants remained in reclaimed water might be of potential risk to environment.Researches about the quality of reclaimed water and its impact to groundwater during recharge were summarized. Based on the water quality standards, effect assessment, and comprehensive ranking, the risk identification system was established to identify risk and assess risk level. And the object and goal for risk management of this project were raised.The object and goal of groundwater contamination risk management during reclaimed water recharge project at Shunyi Segment of Chaobai River was raised based on groundwater contamination risk assessment. The risk management method and provisions including water quality control of reclaimed water, self-purification of surface water, retain of vadose zone, and groundwater protection were carried out according to the analysis of reclaimed water infiltration to groundwater.