数值模拟在污染地下水抽出-处理-回灌修复技术中的应用

Application of numerical simulation in pump-treat-recharge remediation technology of polluted groundwater

受污染地下水对人体健康和生态环境有较深影响,采取经济合理的地下水修复技术尤为关键。抽出-处理-回灌技术是修复污染地下水的典型代表,溶质运移数值模拟是研究地下水污染物迁移转化的重要技术支撑手段。以北京某地块石油类污染地下水为研究对象,针对重污染区域采用中心抽水-四周回灌和对整个污染区采用逐排处理两种方案,运用数值模拟分析不同模式下地下水中污染物的时空迁移规律,确定污染物去除效果。结果表明:针对重污染区优先处理时,将污染物处理达标需要约23 d;针对整个污染区采用逐排处理时,则需要6~7个处理周期(每周期24 d)。对重污染区域优先处理的模式可短期内使污染物浓度大幅降低,有效削减高浓度峰值,结合逐排抽出-回灌的修复模式,可更有效地使全区污染物浓度达到修复目标,两种模式结合使用具备技术可行性与高效性。

Polluted groundwater had a serious impact on human health and ecological environment,so it’s critical to adopt economic and reasonable groundwater remediation technology.Pump-treat-recharge technology was a typical representative method for the remediation of contaminated groundwater,and numerical simulation of solute transport was an important technical support means to study the migration and transformation of groundwater pollutants.Taking the petroleum-contaminated groundwater of a certain site in Beijing as the research object,two schemes were adopted for the heavily polluted area,namely,central pumping and peripheral reinjection,and the whole polluted area was treated row by row.Numerical simulation was used to analyze the temporal and spatial migration of pollutants in groundwater under different modes and determined the pollutant removal effect.The results showed that 23 days were taken about for pollutants to reach the standard when priority treatment was given to the heavily polluted area,and 6~7 treatment cycles(24 days per cycle)were required when adopting row-by-row treatment in the whole pollution area.The priority treatment mode for heavily polluted areas could significantly reduce the pollutant concentration in a short period.It could reduce the peak value of high concentration,and in combination with the row-by-row repair mode,the pollutant concentration can effectively reach the remediation goal.The combination of the two modes showed technical feasibility and efficiency.