The U.S. Environmental Protection Agency intends to conduct a rulemaking and potentially revise portions of a 2015 final rule establishing effluent limitation guidelines for steam electric power plants in response to a complaint from an industry group. The agency also plans to approve a variance from certain aspects of the rule for Duke Energy Corp.'s Edwardsport integrated gasification combined cycle power plant in Indiana.

In an Aug. 14 court filing, the EPA indicated that it plans to move forward with the rulemaking with respect to the effluent guidelines promulgated under the Obama administration in 2015. The rule set limits on the release of toxic metals from certain power plants for the first time in over 30 years.

In numerous actions over the spring, including one in which deadlines associated with the rule were postponed, the EPA indicated its intent to review the effluent guidelines in response to a petition brought by the Utility Water Act Group and others. For the duration of that review, the U.S. Court of Appeals for the 5th Circuit granted a motion to hold litigation of the rule in abeyance.

The new court filing in the matter gives a clearer picture of which portions of the rule the agency has targeted for revision. According to a letter dated Aug. 11 and signed by Administrator Scott Pruitt, the rule has now been carefully reviewed and the EPA chief has determined that a new rulemaking to potentially revise certain technology requirements for two of the six waste streams regulated by the rule — bottom ash transport water and flue gas desulfurization wastewater — is in the public interest.

Moreover, the EPA intends to grant a variance for Duke Energy's Edwardsport plant under which the facility's gasification wastewater would be exempted from some of the effluent rule's requirements. In a letter addressed to Duke Energy and attached to the court filing, the EPA said it is proposing to establish alternative effluent limitations for mercury and total dissolved solids to apply to Edwardsport's gasification wastewater. However, Duke Energy's requested variance for arsenic will not be granted because data suggests the plant is in compliance with the effluent limitations as they are now written for that pollutant, according to the letter.

The agency said the specific technology operating at the power plant was not taken into consideration in developing the effluent guidelines and, therefore, different limits are warranted for that specific facility. A public comment period on the proposal will be held until Sept. 8.

Given these new developments, the EPA asked the 5th Circuit to sever and hold in abeyance all judicial proceedings related to the portions of the effluent rule's requirements for gasification wastewater, bottom ash transport water and flue gas desulfurization wastewater until the new rulemaking is complete. The agency said it will file status reports on the regulatory proceedings every 90 days.

As for the issues remaining in the litigation that are not covered by the EPA's proposed rulemakings, the agency said those matters may proceed if the petitioners in the case wish to continue.

The 5th Circuit case is Southwestern Electric Power Co. et al. v. EPA, (No. 15-60821) and was brought by a number of industry groups and power generators, including the Utility Water Act Group, Southwestern Electric Power Co., Union Electric Co. and Duke Energy Indiana LLC. Environmental groups such as the Sierra Club, Environmental Integrity Project and others have filed to intervene in that litigation. Duke Energy separately filed litigation in the U.S. Court of Appeals for the 7th Circuit over the effluent rule, complaining about excessive cost to the Edwardsport facility.

The EPA's action to postpone the effluent rule deadlines is the subject of an additional lawsuit brought by Earthjustice in the U.S. Court of Appeals for the District of Columbia Circuit.