GROUNDWATER TREATMENT FOR ARSENIC REMOVAL

Arsenic is naturally present in the Earth’s crust and it is released into the groundwater both by natural biogeochemical and anthropogenic processes. There is no one “silver bullet” when it comes to arsenic remediation of groundwater. Removing arsenic may require the use of expensive treatment methods. The handling and disposal of treatment residuals may introduce additional complications. Therefore, source substitution options should be prioritized wherever appropriate. Techniques to remove arsenic from water can be broadly grouped into precipitation processes, adsorption and ion exchange processes, membrane processes, oxidation processes and bioremediation. These methods will be elaborated during the presentation. The selection of the most appropriate method for arsenic removal needs careful pre-evaluation of water quality characteristics, target finished water arsenic concentration, ease of implementation on an existing system, residual management and the cost. Piloting the potential mitigation techniques is an essential procedure to optimize treatment variables and avoid implementing a technology that may not work for unforeseen reasons. Applying the advanced arsenic treatment options to poor rural settings is generally hindered by the de-centralized nature of the populations. However, basic principles can be shared. Many of the conventional technologies can be reduced in scale and conveniently applied at household and small community levels. Socio-economic reality of the target geographical region should never be overlooked. It is undoubtedly the most important aspect influencing the choice of remediation strategy.