ABSTRACT
Reductive dissolution of arsenic (As) is identified as the principle cause for elevated concentrations in confined aquifers of Southeast Asia. In order to use groundwater resources as an alternative for the production of drinking water, oxidative iron-based, subsurface As removal (SAR) offers a sustainable solution. In this study, the results of two SAR pilot plants installed in the Mekong-Delta, Vietnam are presented. For the first time, both the removal efficiency and the evaluation of operational and technical aspects were investigated in order to assess the long-term applicability of the technology. Initial concentrations of As (81 and 10 µg/L) and iron (8.2 and 2.0 mg/L) were successfully lowered to below the WHO drinking water standard. The long-term study of the oxidation/adsorption process showed there was no As breakthrough after more than 28 months operation proving SAR as a suitable mitigation technique with the salient advantage of no toxic waste production and low-energy requirements.
