Advanced treatment technologies in the remediation of seleniferous drainage waters and sediments

Bioaccumulation of selenium (Se) in wetlands and evaporation ponds has created serious hazards to fish and waterfowl in the western United States. Agricultural drainage water is the main source for Se contamination in this region. Treatment technologies currently being evaluated to reduce the Se load in agricultural drainage water include physical, chemical and biological methods. This article focuses on ion-exchange, reverse osmosis, solar ponds, chemical reduction with iron, microalgal-bacterial treatment, volatilization, biological precipitation, and flow-through wetlands to remove Se in water. Advantages and disadvantages of each technology are evaluated and assessed in terms of cost-effectiveness and practical applications in dealing with large volumes of drainage water. With intense research in treatment technologies, it is feasible that a combination of biological, chemical and physical techniques may be employed in the development of a cost-effective strategy to treat agricultural drainage water.