The U.S. Environmental Protection Agency seeks to strengthen limits on wastewater discharges from coal-fired power plants in a proposed regulation announced March 9 that officials say would be the toughest ever proposed for effluent pollution. EPA Administrator Michael Regan said the new "effluent limitation guidelines" for steam-generating electric power plants—which typically are coal plants but can also include oil and gas plants—would reduce pollutants such as selenium, mercury, arsenic, nickel and bromide in discharged wastewater by about 584 million pounds annually.

The regulation also would improve public health, particularly in low-income communities located near power plants.  

The guidelines are numeric limits incorporated by states and EPA regions into the National Pollutant Discharge Elimination System (NPDES) framework. 

The agency proposal is in response to President Joe Biden’s 2021 executive order requiring a review and rescission of any rules enacted during the Trump administration that do not adequately protect public health or the environment. In 2020, the Trump administration released a less-stringent rule to replace one developed in 2015. 

The proposal would establish a limit of zero for all pollutants in flue-gas desulfurization wastewater and a numeric limit for mercury and arsenic in combustion residual leachate. It also addresses wastewater produced by coal-fired plants that is stored in surface impounds, such as coal ash ponds. 

These would be defined as “legacy” wastewater. Through the proposal, EPA seeks comment on whether to develop more stringent discharge standards for these particular types of wastewater.  

Technologies to treat wastewater filled with pollution from coal and other steam-generating power plants, particularly membrane technologies, have evolved over time, said Regan. Agency staff worked with industry groups, utility and power companies, environmental advocates and community organizations to identify the “best economically achievable” technologies to protect public health and communities as they developed an update to the rule, he noted.  “This proposed rule represents an ambitious step toward protecting communities from harmful pollution while providing greater certainty for industry,” Regan said. 

Plants now installing technologies to meet the 2015 and 2020 rules would have more time for compliance with the 2023 rule, EPA said. 

New 'Opt-In' Set If Plants Quit Coal

Additionally, the proposal retains a Trump rule subcategory for coal plants that have committed to stop burning coal by 2028. This group could “opt in” to a compliance path that would allow less- restrictive limits established in the 2015 and 2020 rules. 

An EPA official on a March 8 press call said the agency is aware of more utilities that wanted to “opt in” to this subcategory under the 2020 rule but missed the 2022 deadline. The proposal would extend the opt-in period to allow utilities to either retire a plant early or switch fuels to be able to do so. 

Earthjustice, an environmental advocacy group, was generally supportive of the proposal overall, but took issue with the flexible pathway for utilities to use treatment technologies through 2032 that are already out of date. “We urge EPA to finalize the strongest rule possible as quickly as possible," said Thom Cmar, the group's senior attorney, in a statement. "Power plants have already had many years to comply with these standards, and should not be allowed to wait until the end of this decade.”

Emily Fisher, Edison Electric Institute executive vice president of clean energy and general counsel, countered in an email: "We appreciate the coordinated and holistic approach that Administrator Regan and his team are taking to the suite of environmental regulations for the power sector. Such an approach supports the ongoing clean energy transition that electric companies are leading.” 

The trade group for investor-owned utilities was among entities consulted in the development of the proposal.