水动力控制强化碱活化过硫酸盐原位修复1,2-二氯乙烷污染地下水

针对某受1,2-二氯乙烷污染场地，开展水文地质实验并求解水文地质参数，采用水动力控制强化原位化学氧化技术修复了地下水含水层中受污染的地下水，探究了碱活化过硫酸盐对地下水中目标污染物去除效果，并对地下水水化学因子进行了长期监测。结果表明，实验区含水层渗透系数为7.89 m·d⁻¹，导水系数为101 m²·d⁻¹，在一维稳定流场中二维弥散条件下，含水层纵、横向弥散度α_L和α_T分别为0.89 m和0.089 m，地下水流速为3.85 m·d⁻¹，水动力条件明显优于自然状态，通过水动力控制法干扰地下水流场可有效控制修复药剂在含水层中的扩散速度和影响范围。注药后实验区污染物浓度整体呈下降趋势，在第14天，注药井4 m以内1,2-二氯乙烷浓度低于检出限，药剂修复效果在含水层中可保持28 d。碱活化过硫酸盐降解1,2-二氯乙烷的反应速率常数为0.022 d⁻¹，半衰期为29 d。实验期间地下水中硫酸盐浓度先上升后下降，140 d后恢复至原浓度水平，对实验场地二次污染影响较小。碱活化过硫酸盐在氯代烃类污染场地修复中将有广阔的应用前景。

Hydrodynamic control-enhanced alkali activated persulfate for in situ remediation of 1,2-dichloroethane contaminated groundwater

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.