WASHINGTON (REUTERS) - The United States Environmental Protection Agency (EPA) on Monday (July 26) said it will set stricter requirements for how coal-fired power plants dispose of wastewater full of arsenic, lead and mercury, an important step in reversing one of the Trump administration's major environmental rollbacks.

The EPA said it will work to undo the Trump-era rollback after conducting a science-based review of the 2020 Steam Electric Reconsideration Rule and finding that there are "opportunities to strengthen certain wastewater pollution discharge limits". The agency said it will adhere to limits set prior to the rollbacks as it undertakes a formal process to strengthen the rule.

"In conducting a review of the 2020 rule as directed by President Biden, EPA determined that moving forward with implementing the existing regulations would ensure that water resources are protected now, while we quickly move to strengthen water quality protections and further reduce power plant pollution that can contain toxic metals such as mercury, arsenic, and selenium," EPA Administrator Michael Regan said in a statement.

When the EPA under then President Donald Trump scaled back the effluent limits in August last year, environmental groups said the changes let industry use cheaper, less effective treatment methods on polluted wastewater that puts waterways at risk.

Policy director at the Sierra Club environmental organisation Dalal Aboulhosn said the Biden EPA must move quickly to strengthen the regulation and require the use of available technologies to tackle toxic waste.

"Fixing Trump's rollback as quickly as possible will help ensure that the safest technology is being used across the country, and will help advance the project of restoring the right of all people and every community to clean air, clean water, and a sustainable, healthy climate," Ms Aboulhosn said.