This study demonstrates a groundwater circulation enhanced electrobioremediation process for 1,2-dichloroethane (1,2-DCA) degradation in a simulated heterogeneous aquifer, in which a pair of electrodes were separately implanted between an injection well and an abstraction well and groundwater circulation carries anodic O₂ and cathodic H₂ sequentially into the aquifer forming oxidation and reduction regions. A two-dimensional tank was filled with interbedded sandy-clayed sediments to simulate the field aquifer conditions. It is expected that the interbedded clayed sediments could supply bacteria for biological degradation and also supply Fe(II) for chemical oxidation in the presence of O₂ due to hydroxyl radical (•OH) production. At a constant circulation flow rate of ∼3.5 PVs/day, 1,2-DCA at an initial concentration of ∼8.07 mg/L was degraded to ∼0.65 mg/L (91.9% removal) after 33-day treatment, in which 80–100 mA current was applied to the electrodes after the initial stage of 8-day circulation. Batch experiments proved that 1,2-DCA degradation was mainly attributed to aerobic biological oxidation, with likely contribution of anaerobic reductive dechlorination in certain areas. Chemical 1,2-DCA oxidation was negligible. This study suggests that coupling groundwater circulation and separated electrolysis is effective for stimulating biological 1,2-DCA degradation in heterogeneous aquifers.

中文翻译：

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地下水循环增强模拟非均质含水层中 1,2-二氯乙烷的电生物修复

本研究展示了一种地下水循环增强电生物修复过程，用于模拟非均质含水层中的 1,2-二氯乙烷 (1,2-DCA) 降解，其中一对电极分别植入注入井和抽取井之间，地下水循环携带阳极 O ₂和阴极 H ₂依次进入含水层形成氧化和还原区域。一个二维水箱充满了夹层砂质粘土沉积物，以模拟现场含水层条件。预计互层粘土沉积物可为生物降解提供细菌，并在O _{2存在下为化学氧化提供Fe(II)}由于羟基自由基 (•OH) 的产生。在 ∼3.5 PVs/天的恒定循环流速下，初始浓度为 ∼8.07 mg/L 的 1,2-DCA 在 33 天处理后降解至 ∼0.65 mg/L（91.9% 去除），其中 80在 8 天循环的初始阶段后，将 –100 mA 电流施加到电极上。批量实验证明1,2-DCA降解主要归因于好氧生物氧化，在某些区域可能有厌氧还原脱氯作用。化学 1,2-DCA 氧化可忽略不计。该研究表明，耦合地下水循环和分离电解可有效促进非均质含水层中的生物 1,2-DCA 降解。