The U.S. Environmental Protection Agency (EPA) issued its final rule easing the 2015 regulation for wastewater coming from coal-fired power plants. 

The final rule, known as the Effluent Limitations Guidelines (ELGs), is similar to one proposed last fall but would further extend the timeline for plants to comply. And coal facilities closing, repowering or switching to natural gas by 2028 are exempt.

The change will allow utilities to use cheaper technologies and take longer to comply with pollution reduction guidelines that are less stringent than what the agency originally adopted in 2015. The change is the latest in a string of regulatory rollbacks for coal power under president Trump.

According to the EPA, the changes will help the industry save $140/year while reducing 1 million pounds of pollution per year over the 2015 rule, despite relaxation of the timelines for compliance.

“This new rule replaces a prime example of regulatory overreach that was specifically designed to stack the deck against the coal industry when compared with other fuels. The model wastewater treatment techniques under the new rule can effectively remove pollutants at less cost and with fewer facility modifications than the technologies required by the prior rule, while also allowing for more flexibility in plant maintenance operations. The coal industry wants to be able to compete while also safeguarding important environmental protections – this rule shows that balance is possible,” National Mining Association President and CEO Rich Nolan said.

The revised rule is expected to affect 75 out of 914 coal power plants nationwide, compared to more than 100 plants affected by the 2015 rule. That’s in part because coal power usage has dropped dramatically over the past decade and many plants have been shuttered.

E&E News reported that the new rule would set a daily maximum limit on selenium at 76 micrograms per liter — or more than three times the Obama-era limit of 23 micrograms per liter. The monthly average treatment in the new rule is 31 micrograms per liter, compared with 12 micrograms per liter in the Obama-era rule.

The new rule will also allow power plants to use a shorter biological treatment process that is cheaper, but can also result in higher selenium levels.

Compared with the 2015 rule, this rule allows significant increases of selenium that enters waterways in discharges of wastewater that came from cleaning power plants' air filters.

But many plants have been exempted from using the biological treatment process at all, allowing their mercury, arsenic and nitrogen levels to increase significantly.

Power plants with "high flows" of wastewater and coal power plants that are used only during peak power demand are exempted from the biological treatment requirement entirely.

Those plants are allowed to release nearly 10 times as much mercury — 788 micrograms per liter daily — as plants that are not exempted from the treatment requirement, which are limited to 85 micrograms per liter daily.

The rule gives power plants until the end of 2025 to comply with the new rules but also says EPA would establish a voluntary incentive program whereby power plants would have until 2028 to comply if they decide to include more biological treatment.

The Trump rule also makes changes to new requirements the Obama administration set on water used to flush plants of waste left over when coal is burned, known as bottom ash.

The Obama administration sought to change that by requiring all power plants to dispose of the ash while continuously recycling the process water, and not discharging any of it, because it can be highly toxic.

While the proposal would allow 10 percent of the process water to be discharged daily, a senior agency official said the final rule allows states to make case-by-case decisions.

Under the rule, plants that are retiring by 2028 do not have to treat their wastewater or dry dispose of their bottom ash.