Center of Applied Research, Karlsruhe University of Applied Sciences, Moltkestr. 30, 76133, Karlsruhe, Germany; Laboratory of Industrial and Synthetic Organic Chemistry (LISOC), Department of Chemistry and Chemical Technologies, University of Calabria, Via Pietro Bucci 12/C, 87036, Arcavacata di Rende, CS, Italy; Institute on Membrane Technology, National Research Council (ITM-CNR), Via Pietro Bucci 17/C, 87036, Arcavacata di Rende, CS, Italy.
Department of Mechatronics and Sensor Systems Technology, Vietnamese-German University, Le Lai Street, 822096, Binh Duong Province, Viet Nam; Department of Separation Science, School of Engineering Science, Lappeenranta-Lahti University of Technology, Sammonkatu 12, 50130, Mikkeli, Finland.
Water Res. 2020 Aug 15;181:115929. doi: 10.1016/j.watres.2020.115929. Epub 2020 May 16.
The principle of subsurface arsenic removal (SAR) from groundwater is based on oxidation and adsorption reactions by infiltrating oxygen into the anoxic aquifer and the immobilization of arsenic (As) onto freshly formed iron (Fe)-(hydr)oxides. In this study, a pilot-scale plant for SAR has been subject to long term testing in the Mekong Delta, Vietnam. Initial concentrations of Fe (8.4 ± 1.3 mg L) and As (81 ± 8 μg L) in the exploited groundwater were successfully lowered to below the WHO guideline value limits for drinking water of 0.3 mg L and 10 μg L, respectively. Adsorption and co-precipitation of As with Fe-(hydr)oxides could be identified as the principal mechanism responsible for the As removal from groundwater, demonstrating the feasibility of SAR as a low-cost and zero-waste solution over a period of two years. However, naturally occurring geochemical reducing conditions and high ammonium levels in the groundwater delayed the removal of manganese (Mn). An additional post-treatment filtration for Mn-removal was temporarily used to comply with the Vietnamese drinking water standard until a Mn-mitigation was achieved by the SAR process. In contrast to most As-remediation technologies, SAR appears to be a long-term, sustainable treatment option with the salient advantage of negligible production of toxic waste, which with ex-situ processes require additionally management costs.
地下水地下砷去除 (SAR) 的原理基于通过向缺氧含水层中渗透氧气以及将砷 (As) 固定到新形成的铁 (Fe)-(水合) 氧化物上，发生氧化和吸附反应。在本研究中，一个 SAR 的中试规模工厂在越南湄公河三角洲进行了长期测试。开采地下水中的初始铁浓度 (8.4 ± 1.3 mg/L) 和砷浓度 (81 ± 8 μg/L) 成功降低至世界卫生组织饮用水指导值限制以下，分别为 0.3 mg/L 和 10 μg/L。砷与 Fe-(水合) 氧化物的吸附和共沉淀可被确定为地下水砷去除的主要机制，证明了 SAR 在两年期间作为低成本和零废物解决方案的可行性。然而，地下水中存在的天然地球化学还原条件和高铵水平延迟了锰 (Mn) 的去除。为了遵守越南饮用水标准，暂时使用额外的后处理过滤来去除 Mn，直到通过 SAR 工艺实现 Mn 缓解。与大多数除砷技术相比，SAR 似乎是一种长期、可持续的处理方法，其突出优点是几乎不产生有毒废物，而对于原位处理过程则需要额外的管理成本。
