Remediation system and method based on pollution obstruction for underground water with DNAPL pollutant

A remediation method using a remediation system based on pollution obstruction for underground water with dense nonaqueous phase liquid (DNAPL) pollutant, the remediation system including a vertical obstructing wall, a pump-out treating unit and a recharging unit, wherein

• the vertical obstructing wall is arranged in a slot at a periphery of a polluted area to obstruct polluted underground water within the vertical obstructing wall,
• the pump-out treating unit comprises a plurality of water pumping wells and an overground treatment facility that are distributed in the polluted area, the plurality of the water pumping wells being configured to pump the polluted underground water out and send it into the overground treatment facility so as to treat and remove DNAPL pollutants,
• the recharging unit comprises a plurality of recharging wells, the plurality of recharging wells being arranged in the same slot where the vertical obstructing wall is arranged, water that has been treated by the overground treatment facility being recharged into a target aquifer in the polluted area by the plurality of the recharging wells, the plurality of recharging wells being arranged on a side of the vertical obstructing wall facing towards the polluted area in such a manner that they are closely adjacent to the vertical obstructing wall, and
• a lower end of the vertical obstructing wall is buried in a water resisting floor of the aquifer in the polluted area to form a sealing area with the water resisting floor, and a lower end of each of the recharging wells is located 15 to 30 mm above the water resisting floor,
• the remediation method comprising steps of:
• (1) deploying the vertical obstructing wall, the pump-out treating unit and the recharging unit based on a polluted area and a pollution level;
• (2) pumping the polluted underground water to the ground surface by the pump-out treating unit for treatment to remove DNAPL;
• (3) adding a surfactant to the water that has been treated by the pump-out treating unit, then enabling the treated water to enter the target aquifer by the recharging unit and leaving it alone for a given interval time to dissolve and remove DNAPL in the aquifer;
• and
• (4) repeating the steps (2) to (3) to circularly dissolve and remove the DNAPL.