ENV-16-101 Selenium Treatment of Refinery Wastewater Effluents Using Physical/Chemical and Biological Treatment Technologies

Description:

Technically feasible selenium (Se) treatment technologies include Zero-Valent Iron (ZVI), Ion Exchange (IX), and biological treatment. Se removal using biological treatment has been found both performance- and cost-effective for the removal of selenite and selenate. Pilot studies were conducted on the refinery wastewaters using the anoxic/anaerobic fluidized bed reactor (FBR) treatment technology for Se removal. The FBR pilots demonstrated consistent dissolved Se reduction in the range of 10 to 15 μg/L for a refinery wastewater. However, the average total Se concentrations were higher in the treated effluent due to presence of reduced elemental Se particles. Hence, tertiary treatment (e.g., media filtration, membranes, etc.) of the FBR effluent will be required to remove the Se-containing suspended solids to achieve low levels of total Se.