New membrane-based processes remove arsenic from water

This paper is an overview of pressure-driven membrane processes, both conventional and innovative, that can be used for the removal of arsenic from aqueous streams, such as potable water or effluents. Those processes employ semi-permeable membranes to separate arsenic species from non-hazardous components of the water. Applications of "established" processes, including reverse osmosis, nanofiltration, ultrafiltration, and microfiltration are discussed. However, the main focus of this publication is on a group of new hybrid processes that combine membrane filtration with the enlargement of arsenic-bearing species. This enlargement can be achieved using various mechanisms such as coagulation, adsorption, or ion exchange. The processes are compared in terms of their ability to meet water quality criteria, their technical feasibility, and their overall impact on the environment. The paper reviews results of bench-scale and pilot-scale studies and discusses feasibility of furth...