Selenium Speciation and Control Technologies for Sulfate-Rich Wet FGD Systems

Historically, coal, which is used to generate more than half of the electricity in the United States, has been an abundant and low-cost source of energy for electricity generation. However, coal has a range of environmental disadvantages, which include emissions of selenium via the flue gas and via environmental releases during the subsequent processing and disposal of byproducts. The development of selenium management technology is complicated by a limited understanding of selenium chemistry in pollution control systems and by challenges in measuring the amount and form of selenium in these systems. This project will develop technology to reduce selenium water discharges from coal-fired power plants equipped with flue gas desulfurization units. In Phase I, a selenium control strategy was developed, and laboratory tests were conducted to identify the conditions under which selenium could be converted into a chemical form that can be removed easily from the wastewater. In Phase II, additional laboratory tests will be conducted to further refine the selenium control strategy. Then, pilot-scale tests at an electric utility will be conducted to demonstrate the technology on a larger scale using actual flue gas from a coal-fired power plant. Commercial Applications and other Benefits as described by the awardee: The technology should have extensive commercial applications in the electric utility industry at both new and existing coal-fired power plants equipped with wet flue gas desulfurization scrubbing systems. The public will benefit from reduced exposure to selenium and reduced environmental discharges of selenium