During the last two decades nitrate contaminated groundwater has become an extensive worldwide problem with wide-reaching negative effects on human health and the environment. In this study, a combination of electrocoagulation (EC) and electrooxidation (EO) was studied as a denitrification process to efficiently remove nitrates and ammonium (a by-product produced during EC) from real polluted groundwater. Initially, EC experiments under batch operating mode were performed using iron electrodes at different applied current density values (20–40 mA cm⁻²). Nitrate percentage removal of 100 % was recorded, however high ammonium concentrations were performed (4.5–6.5 mg NH₄⁺-Ν L⁻¹). Therefore, a continuous flow system was examined for the complete removal of both nitrates and EC-generated ammonium cations. The system comprised an EC reactor, a settling tank and an EO reactor. The applied current densities to the EC process were the same as those in the batch experiments, while the volumetric flow rates were 4, 6 and 8 mL min⁻¹. Regarding the current density of the EO process was kept constant at the value of 75 mA cm⁻². The percentage nitrate removal recorded during the EC process ranged between 52.0 and 100 %, while the NH₄⁺-N concentration at the outlet of the EO reduced significantly (53–100 %) depending on the applied current density and the volumetric flow rate. Also, the dissolved iron concentration in the treated water was always below the legislated limit of 0.2 mg L⁻¹ (up to 0.027 mg L⁻¹). These results indicate that the proposed hybrid system is capable of denitrifying real nitrate contaminated groundwater without generating toxic by-products, therefore making the water suitable for human consumption.

在过去的二十年中，硝酸盐污染的地下水已成为一个广泛的世界性问题，对人类健康和环境产生广泛的负面影响。在这项研究中，研究了电凝 (EC) 和电氧化 (EO) 的组合作为一种反硝化过程，以有效地从实际受污染的地下水中去除硝酸盐和铵（电凝过程中产生的副产品）。最初，批量操作模式下的 EC 实验是使用铁电极在不同的外加电流密度值 (20–40 mA cm ^-2 ) 下进行的。记录了 100 % 的硝酸盐去除率，但是进行了高铵浓度（4.5–6.5 mg NH ₄ ⁺ -Ν L ^-1）。因此，检查了连续流动系统以完全去除硝酸盐和 EC 生成的铵阳离子。该系统包括EC反应器、沉降罐和EO反应器。施加到 EC 过程的电流密度与批量实验中的电流密度相同，而体积流速为 4、6 和 8 mL min ^-1。关于 EO 过程的电流密度保持恒定在 75 mA cm ^-2的值。在 EC 过程中记录的硝酸盐去除百分比介于 52.0 和 100% 之间，而 NH ₄ ⁺根据施加的电流密度和体积流量，EO 出口处的 -N 浓度显着降低（53-100%）。此外，处理过的水中的溶解铁浓度始终低于 0.2 mg L ^{-1 的}法定限值（高达 0.027 mg L ^-1）。这些结果表明，所提出的混合系统能够对真正受硝酸盐污染的地下水进行反硝化，而不会产生有毒副产品，因此使水适合人类饮用。