To evaluate energy efficient concepts for the modular treatment of brackish water, pilot trials for groundwater desalination and arsenic (As) removal were carried out in the Mekong Delta, Vietnam. Groundwater here is affected by naturally occurring high iron (Fe²⁺) and As concentrations, while, in coastal regions, groundwater is additionally contaminated by high salinity mostly due to seawater intrusion. Desalination was conducted by membrane capacitive deionization (MCDI), which shows low specific energy consumption (SEC). Anoxic groundwater with As(III) and Fe²⁺ was treated using a pre-oxidation step called subsurface arsenic removal (SAR) with the main advantage that no As-laden waste is produced. The pilot plant was operated using a photovoltaic system (3 kW_p) and a small wind turbine (2 kW_p). The SEC of drinking water produced was 3.97 kWh/m³. Total dissolved solids (TDS) of 1,560 mg/L were lowered to 188 mg/L, while Fe²⁺ was reduced from 1.8 mg/L to the below detection limit and As from 2.3 to 0.18 μg/L. The results show that SAR is a feasible remediation technique for Fe²⁺ and As removal in remote areas, and demonstrate the potential of MCDI for brackish water desalination coupled with renewable energies. However, improvements in energy demand of the MCDI module can still be achieved.

为了评估微咸水模块化处理的节能概念，在越南的湄公河三角洲进行了地下水淡化和砷去除的试验性试验。这里的地下水受到自然产生的高铁（Fe ²⁺）和砷（As）浓度的影响，而在沿海地区，地下水又被高盐度污染，这主要是由于海水的入侵。通过膜电容去离子（MCDI）进行脱盐，这显示出较低的比能耗（SEC）。使用称为次表面砷去除（SAR）的预氧化步骤处理了含As（III）和Fe ^2+的缺氧地下水，其主要优点是不会产生含As废物。中试工厂使用光伏系统（3 kW _p）和一台小型风力发电机（2 kW _p）。产生的饮用水的SEC为3.97 kWh / m ³。总溶解固体（TDS）从1,560 mg / L降至188 mg / L，而Fe ²⁺从1.8 mg / L降至检测限以下，As从2.3降至0.18μg/ L。结果表明，SAR是一种在边远地区去除Fe ²⁺和As的可行修复技术，并证明了MCDI在微咸水淡化与可再生能源结合中的潜力。但是，仍然可以改善MCDI模块的能源需求。