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Effluent Guidelines

Steam Electric Power Generating Effluent Guidelines - 2015 Final Rule

EPA, on September 30, 2015, finalized a rule revising the regulations for the Steam Electric Power Generating category (40 CFR Part 423). The rule sets the first federal limits on the levels of toxic metals in wastewater that can be discharged from power plants, based on technology improvements in the steam electric power industry over the last three decades.
  • On an annual basis, the rule is projected to reduce the amount of toxic metals, nutrients, and other pollutants that steam electric power plants are allowed to discharge by 1.4 billion pounds and reduce water withdrawal by 57 billion gallons
  • Estimated annual compliance costs for the final rule are $480 million
  • Estimated benefits associated with the rule are $451 to $566 million

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Steam electric plant discharges include arsenic, lead, mercury, selenium, chromium, and cadmium. Many of these toxic pollutants, once in the environment, remain there for years.

The current regulations for the industry were last updated in 1982 and do not adequately address toxic metal discharges. The 1982 rule focused on settling out particulates rather than treating dissolved pollutants.

New technologies for generating electric power and the widespread implementation of air pollution controls over the last 30 years have altered existing wastewater streams or created new wastewater streams at many power plants, particularly coal-fired plants. The 2015 rule addresses these changes in the industry.

Affected Facilities

Illustration of key wastestreams at electric power plantKey Wastestreams - Click to enlargeCertain coal-fired steam electric power plants will be affected by this rule. EPA estimates that about 12 percent of steam electric power plants will incur some costs.

Regulatory Requirements

The final rule sets new or additional requirements for wastewater streams from the following processes and byproducts:
  • flue gas desulfurization
  • fly ash
  • bottom ash
  • flue gas mercury control
  • gasification of fuels such as coal and petroleum coke

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Final Rule


Documents related to the rulemaking can be found on EPA’s docket at The Docket Number is EPA-HQ-OW-2009-0819.

Background Documents

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2020 Reconsideration Rule

On August 31, 2020, EPA issued a final rule which updated the requirements for flue gas desulfurization (FGD) wastewater and bottom ash (BA) transport water.

Additional Information

For additional technical information about the final rule, please contact Richard Benware ( or 202-566-1369. For economic information please contact James Covington ( or 202-566-1034.

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