EPA Proposes Effluent Limitation Guidelines for Steam-Electric Power Plant Discharges
On April 19, 2013, EPA released its proposed effluent limitation guidelines (ELGs) for the steam-electric power generating point source category. The proposed ELGs, when finalized, will establish uniform national technology-based treatment standards for existing and new sources of wastewater from steam-electric power generating facilities. The final rule will have a major impact on coal-fired power plants in Kentucky. The ELGs for power plants were last updated in 1982. Since that time, the use of advance air pollution control systems has increased significantly at coal-fired power plants. As a result, EPA has found that wastewater streams associated with air pollution control equipment, such as wet scrubbers, contain additional levels of metals and other pollutants beyond those that were identified in 1982.
EPA’s proposed rule sets out four preferred combinations of treatment options for existing sources that are under consideration for establishing best available technology economically achievable (BAT) effluent limitations on various wastewater streams. Under the most stringent preferred options for wet flue-gas desulfurization unit wastewaters, EPA has proposed effluent limits for mercury, arsenic, selenium, and nitrates based upon use of physical/chemical precipitation and subsequent biological treatment. Dry handling would be required under all four preferred options for fly ash transport water, with the exception of fly ash transport water for very small units. For bottom ash transport water, only one of the options would require dry handling/closed loop systems for units with more than 400 MW generating capacity. Other units could continue to utilize surface impoundments for treating bottom ash transport water. All four preferred options also would allow use of impoundments to achieve total suspended solids and oil and grease effluent limitations for coal combustion residual leachate.
A significant aspect of the proposed ELG is that it would provide existing facilities at least three years from the effective date of the final rule to identify compliance plans and schedules for meeting the final ELGs. Specifically, BAT limitations for existing sources would apply on a date determined by the state permitting authority that is as soon as possible after the next NPDES Permit is issued in the permitting cycle beginning July 1, 2007. EPA expects that BAT limitations would become effective at all existing coal-fired units by no later than July 1, 2022. EPA recognized in the proposal that existing facilities need time to study available technologies and operational measures and to subsequently design, install, and optimize the technology at each facility before meeting the final BAT limitations.
EPA also noted that the proposed ELG implementation schedule for existing sources was important for coordinating the ELG with the promulgation of the final coal combustion residual (CCR) disposal regulation. Both rules are now expected to be finalized in mid-2014. Another significant development in the proposed ELG is EPA’s acknowledgement that new data and information have become available that have the potential to significantly reduce EPA’s determination of the nature and extent of the risk of CCR disposal. Thus, EPA noted that its current thinking is that the new data provides strong support for a conclusion that CCR disposal should be regulated under RCRA Subtitle D as nonhazardous waste in its final rule, and not under RCRA Subtitle C as a hazardous waste.
The proposed ELG rule is expected to be published in the Federal Register in late May 2013.
To view a complete PDF of the March/April 2013 issue of the Environmental Letter, click HERE.