南水北调中线总干渠水质健康风险与控制技术研究

Study on health risks of water quality and control technique for the main canal of the middle route project in south-to-north water transfer

南水北调中线总干渠内排段因工程建设特点,污染物可随地下水进入干渠,致干渠水质存在健康风险,直接影响受水地区人民的身体健康。本研究在总干渠风险污染源解析识别的基础上,通过小试,确定了"复配介质渗透反应格栅(PRB)修复"和"水力截获"两控制技术。在现场中试基础上,建成"硝酸盐污染地下水的PRB修复技术示范工程"和"水力截获技术工程化试验示范工程"。工程试验结果显示:复配介质PRB修复技术对硝酸盐氮污染物修复率90%以上;水力截获技术对铬、亚硝酸盐氮和硝酸盐氮等风险污染物截获率均达到90%以上,符合《地下水质量标准》(GB/T14848-9)Ⅲ类水质要求。可有效应对总干渠水质的健康风险,保证南水北调中线总干渠内排段乃至全线的水质安全。

Due to the construction characteristics of the inner drainage section on the main canal of the middle route project in south-to-north water transfer, pollutants might enter into the canal through groundwater, which may cause health risks to water quality of the main canal, and directly impact the health of the people living in this area. Based on the resolution identification for risk pollution sources in the main canal, two technical measures of “com- plex media permeable reactive barrier （PRB） repair” and “hydraulic capture” for controlling the risk were deter- mined through pilot experiment. On the basis of field experiment, the technology demonstration projects of “nitrate polluted groundwater repaired by PRB technique” and “engineering test of hydraulic capture technique” were es- tablished. Engineering test results showed that repair rate can reach above 90% for the nitrate contamination by complex media PRB repair, the interception rates of “hydraulic capture” for risky pollutants of chromium, nitrite nitrogen and trate nitrogen can be over 90%. The quality of water can meet the class III water standard of groundw- ater quality （ GB/T14848-9 ） after the two engineering techniques were employed. The application of “ complexmedia PRB repair” and “hydraulic capture”techniques can canal, and assure water safety for the inner drainage section the whole line in south-to-north water transfer. effectively respond to health risks of water of the main on the main canal of the middle route project, even forthe whole line in south-to-north water transfer.