In November of 2015 the US EPA published the final Effluent Limitations Guidelines and Standards (ELGs) for the Steam Electric Power Generating Point Source Category in the Federal Register (40 CFR Part 423). The rule became effective January of 2016, but in response to legal challenges was revised in August of 2020. The ELGs are technology-based and set the first federal limits of toxic metals in wastewater discharged from power plants while also addressing discharges from technologies and wastewater streams that were not common or well-studied during the 1982 issuance of the Rule.

Although coal, oil and petroleum coke-fired power plants are subject to the rule changes, EPA identified that the majority of facilities which are expected to incur costs to comply with the final ELG are coal-fired plants, plants that co-fire coal and gas, or plants that burn oil. There are two key elements of the rule impacting power plants that burn coal:

• Numeric limits for mercury, arsenic, selenium and nitrites/nitrates on the discharge of FGD wastewater
• High recycle rate systems for bottom ash transport water with an allowable purge not to exceed 10% of the dewatering system volume

AECOM Process Technologies applies our expertise in power plant operations, wastewater treatment and CCR management to arrive at often lower cost solutions for ELG compliance.