On November 3, 2015, the US EPA published the final Effluent Limitations Guidelines and Standards for the Steam Electric Power Generating Point Source Category (ELGs) in the Federal Register. The rule became effective on January 6, 2016. The ELGs are intended to control discharges from new technologies and wastewater streams that were not common or well-studied during the 1982 issuance of the ELGs.
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. Key elements of the rule include the following:
New limits will be implemented through National Pollutant Discharge Elimination System (NPDES) permits as soon as possible starting November, 2018, but no later than December 31, 2023. To determine “as soon as possible” the permitting authority must consider 1) the time required to expeditiously plan, design, procure and install equipment, including the time needed to raise capital; 2) changes planned or underway at the facility to respond to regulations for greenhouse gas or disposal of coal combustion residuals; 3) an initial commissioning period to optimize installed FGD wastewater equipment; and 4) other factors as appropriate. The “as soon as possible” date can be different for individual wastestreams as determined by the permitting agency’s review of information submitted by the permittee.
Facilities willing to treat Flue Gas Desulfurization (FGD) wastewater using evaporation technologies can enter an optional program. They would be subject to more stringent limits for the resulting discharge of brine concentrator distillate and / or crystallizer condensate, but would be guaranteed a maximum implementation date (up to December 31, 2023).
FGD wastewater, fly ash transport water, bottom ash transport water, Flue Gas Mercury Control (FGMC) wastewater, and gasification wastewater generated prior to the site-specific required date to implement the final ELGs are subject to the numeric limits established in the 1982 ELG rule for total suspended solids (TSS) and oil and grease, resulting in no practical change of existing numeric limits for these wastewaters.
These streams cannot be discharged after reuse or recycling, with the exception of fly ash or bottom ash transport water which can be reused as FGD makeup and would subsequently be subject to the FGD wastewater limits when discharged.
For small electric generating units (EGUs) that have a total nameplate generating capacity of 50 megawatt (MW) or less and for oil-fired EGUs, the ELGs set limits for TSS and oil and grease for FGD wastewater, fly ash transport water, bottom ash transport water, FGMC wastewater and gasification wastewater equal to the existing limits for low volume waste, resulting in no practical change of existing numeric limits for these facilities.
Establishment of effluent limitations continue to be reserved for further consideration, resulting in no practical change of existing requirements for this waste stream.