单井抽出-处理-回渗循环技术修复效果关键影响因素研究

Key impact factors of remediation performance of single well pumping-treatment-recharge cyclical technique

采用单井抽出-处理-回渗循环污染地下水修复技术(单井循环技术)原位修复石化场地三氯乙烯(TCE)污染地下水。采用室内试验和数值模拟相结合的方法,通过关键影响因素的不同情景设置,模拟修复过程中污染羽的时空变化情况,明确关键因素对污染物去除的影响。结果表明:修复1,2,3,4,5,6,13,20 d后,TCE去除率分别为27.29%、34.94%、43.65%、54.12%、66.47%、75.88%、91.76%和92.35%;含水层渗透系数(K)和抽出回渗量(Q)是TCE去除的关键影响因素,其中Q的影响较为明显;污染物去除率(r)与修复时间(t)、Q和K之间存在定量关系(r=22.5lnt+6.3ln(KQ)+2.30),推导出的定量关系表达式有助于指导实际污染场地应用时抽出回渗量的设计。

Single well pumping-treatment-recharge cyclical remediation technique can be used for trichloroethylene(TCE)contaminated groundwater remediation in petrochemical sites.After indoor experiments and numerical simulations were combined and various scenarios of key factors were developed,the spatial and temporal variations of pollution plume during the remediation process were simulated and influences of key factors upon removing pollutants were quantitatively assessed.The results indicate that the removal rate of TCE in groundwater reached 27.29%,34.94%,43.65%,54.12%,66.47%,75.88%,91.76%,and 92.35%after 1,2,3,4,5,6,13,and 20 d of remediation,respectively.The aquifer permeability coefficient(K)and pumping-recharge capacity(Q)are key impact factors of TCE removal,the latter more significant.A quantitative relationship between pollutant removal rate(r)and remediation time(t),Q and K exists(r=22.5lnt+6.3ln(KQ)+2.30),and the equation regarding this quantitative relationship can contribute to calculating pumping-recharge capacity when applying this technology in real polluted sites.