Abstract：
Groundwater contamination near landfills is commonly caused by leachate leakage, and permeable reactive barriers (PRBs) are widely used for groundwater remediation. However, the deactivation and blockage of the reactive medium in PRBs limit their long-term effectiveness. In the current study, a new methodology was proposed for the in situ regeneration of PRB to remediate leachate-contaminated groundwater. CO2 coupled with oxidants was applied for the dispersion and regeneration of the fillers; by injecting CO2 to disperse the fillers, the permeability of the PRB was increased and the oxidants could flow evenly into the PRB. The results indicate that the optimum filler proportion was zero-valent iron (ZVI)/zeolites/activated carbon (AC) = 3:8:10 and the optimum oxidant proportion was COD/Na2S2O8/H2O2/Fe2+ = 1:5:6:5; the oxidation system of Fe2+/H2O2/S2O82- has a high oxidation efficiency and persistence. The average regeneration rate of zeolites was 72.71%, and the average regeneration rate of AC was 68.40%; the permeability of PRB also increased. This technology is effective for the remediation of landfills in China that have large contaminated areas, an uneven pollutant concentration distribution, and a long pollution duration. The purification mode of long-term adsorption and short-time in situ oxidation can be applied to the remediation of long-term high-concentration organically polluted groundwater, where pollution sources are difficult to cut off.
摘要：
垃圾填埋场附近的地下水污染通常是由渗滤液泄漏引起的，和渗透性反应屏障（PRB）被广泛用于地下水修复。然而,PRB中反应介质的失活和阻塞限制了它们的长期有效性。在目前的研究中,提出了一种新的PRB原位再生方法，以修复渗滤液污染的地下水。将CO2与氧化剂结合用于填料的分散和再生；通过注入CO2以分散填料，PRB的渗透率增加，氧化剂可以均匀地流入PRB。结果表明，最佳填料比例为零价铁（ZVI）/沸石/活性炭（AC）=3：8：10，最佳氧化剂比例为COD/Na2S2O8/H2O2/Fe2=1：5：6：5;Fe2/H2O2/S2O82-的氧化体系具有较高的氧化效率和持久性。沸石的平均再生率为72.71%,AC的平均再生率为68.40%；PRB的渗透率也增加。该技术对我国污染面积较大的垃圾填埋场的修复是有效的,污染物浓度分布不均匀，和长时间的污染。长期吸附和短时间原位氧化的净化模式可应用于长期高浓度有机污染地下水的修复,污染源难以切断的地方。
