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摘要
In this study, the hydrological tests were conducted to solve the hydrological parameters of a 1,2-dichloroethane contaminated site. The hydrodynamic control-enhanced in-situ chemical oxidation was used to remediate the 1,2-dichloroethane contaminated groundwater in aquifer. The removal effect of target pollutant in groundwater by alkali activated persulfate (PS) was tested. A long term monitoring for the water chemical factors of groundwater was performed. The results showed that the permeability coefficient and the hydraulic conductivity of the studied aquifer were 7.89 m·d?1 and 101 m2·d?1, respectively. Under the condition of two-dimensional dispersion in one-dimensional steady flow field, the calculated groundwater velocity was 3.85 m·d?1 according to the advection-dispersion-reaction equation, and the longitudinal coefficient αL and lateral dispersion coefficient αT were 0.89 m and 0.089 m, respectively. The corresponding hydrodynamic conditions were significantly superior to natural conditions. The diffusion rate and influence range of remediation chemicals in aquifer could be effectively controlled by the disturbance of groundwater flow field with the hydrodynamic control method. After injecting the oxidation agents, the concentration of 1,2-dichloroethane in the studied area decreased generally, and the effective radius of the injection well was around 4 m. On the 14th day, the concentration of 1,2-dichloroethane around the injection well was below the detection limit, and the remediation effect of agents has maintained until 28 days. During this pollutant-removal period, the reaction rate constant of 1,2-dichloroethane degradation by alkali activated persulfate was 0.022 d?1, and the half-life was 29 d. Although the concentration of sulfate in the groundwater experienced an increase after 56 days, it returned to the original level before the injection on the 140 day. It indicated that the integrated technique applied in this study had less impact on the studied area. This alkali activated persulfate will have broad application prospects in chlorinated hydrocarbons contaminated sites.
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