Maryland regulators have decided to make three power plants in the state reduce toxic wastewater discharges by 2020 under a federal regulation that the Trump administration has delayed and indicated it may roll back.Morgantown Generating Station on the shore of the Potomac River is one of three Maryland power plants that will need to make reductions in toxic wastewater discharges by 2020. (Chesapeake Bay Program)

Heeding arguments made by environmental groups and some state lawmakers, the Maryland Department of the Environment gave NRG Energy until Nov. 1, 2020, to meet new limits on the discharges of certain pollutants — including toxic metals like arsenic, mercury and selenium — at its three plants.

The affected generating stations are Morgantown, on the lower Potomac River in Charles County; Chalk Point, on the Patuxent River in Prince George’s County; and Dickerson, also on the Potomac north of the District of Columbia, in Montgomery County. The facilities discharge water that’s been used in their air pollution scrubbers and to flush bottom ash out of their boilers.

In making its final determination on the renewal of the plants’ five-year discharge permits, the MDE backed away from its earlier, tentative decision to give the facilities up to five years before they’d have to curtail the discharges under “effluent limitations guidelines” from the U.S. Environmental Protection Agency.

The EPA finalized those limits in 2015, making them the first federal limits on toxic metals and other harmful pollutants discharged to rivers and streams by coal-burning power plants. Citing technology improvements over the last three decades, the agency required coal plants to install or upgrade wastewater treatment systems or otherwise adjust the plant’s operations to curtail such discharges.

The EPA decreed at that time that the rule would be phased in starting this year, with all plants to be in compliance by 2023. But last year, responding to industry complaints about the rule’s cost, the EPA initially stayed the rule, and then delayed its effective date to 2020 or beyond while the agency considered revisions. Environmental groups sued, and the case is pending in federal appeals court.

In the face of such uncertainty, the MDE had at first proposed giving the plants the option of complying with the federal rule by November 2020 or delaying until 2023 to await potential changes. Environmental groups, some lawmakers and others had submitted written comments urging the MDE not to wait, citing the impacts such discharges could be having on fish and human health.

(Lucidity Information Design, LLC)In a written response to those comments, the MDE said it never intended to delay implementation of an active regulation. While the EPA rule did allow for granting more time beyond Nov. 1, 2020, the MDE said it had received no proposal from the company specifically arguing that it needed more time to comply. Indeed, the MDE noted that at the Morgantown plant, for instance, the company has already installed an advanced biological treatment system to help it meet the new limits.

The MDE still gave the company an option to delay compliance until 2023 but, if it did so, it would have to meet even stricter discharge limits.

An NRG spokesman referred questions to GenOn, a one-time NRG subsidiary that owns the plants and has recently spun off from the Princeton, NJ-based energy company. A GenOn spokeswoman did not respond to requests for comment. The company had submitted comments to state regulators urging them to wait until the EPA rulemaking was complete before imposing any new standards, according to the MDE, but it also acknowledged that it had done much already to meet the rule.

Environmentalists welcomed the MDE’s decision, though they said it did not resolve all of their concerns.

“I don’t like the flexibility in compliance deadlines,” said Abel Russ, an attorney with the Environmental Integrity Project, a DC-based nonprofit. But he said he could accept it as an incentive to get the plants to reduce pollution even more, and he noted that the plants would be required to report their progress every six months, so the public could tell if they are trying to evade compliance.

Still, Russ said in a statement that his group was pleased to see that the MDE “is following the law and stepping up to protect the environment at a time when the EPA is actively trying to undermine environmental protection.”

The MDE imposed additional requirements at two of the plants. For Dickerson, upriver from the District’s water supply intake, the state required monitoring the discharge for bromide, which is associated with cancer-causing byproducts in drinking water. The plant also is barred from using any bromine-containing chemicals in its treatment process.

At Morgantown, where the Potomac Riverkeeper had obtained aerial photographs of a reddish plume coming from one outfall last summer, the MDE said it had been unable to verify any inappropriate discharge. But state regulators are requiring the plant staff to make a daily visual inspection of the outfalls emptying into the discharge canal where the plume was seen.

“We’re happy that MDE adopted many of the additional restrictions we pushed for,” Potomac Riverkeeper Dean Naujoks said in a statement.