New Effluent Limits Set for Steam Electric Plants



On September 30, 2015, the EPA Administrator signed the Final Rule on Effluent Guidelines and Standards for the Steam Electric Power Generating Point Source Category.  This rule establishes the first national level limits on certain metals and other pollutants commonly found in steam electric plant discharges.  The final rule amends the current categorical effluent limitations under 40 CFR Part 423.

The final rule constitutes the first change to the effluent limits on the steam electric category since 1982.  It targets wastewater discharges from specific plant processes such as flue gas desulfurization (FGD), flue gas mercury control (FGMC), fly ash and bottom ash transport, and gasification.  The effluent limitations vary according to the process and type of discharge.   

Existing Sources with Direct Discharges 

The final rule established Best Available Technology (BAT) limitations as follows: 

  • Fly/bottom ash transport and FGMC – numeric limitation for TSS (similar to current BPT limits) and zero discharge for all other covered pollutants
  • FGD and gasification – TSS numeric effluent limitations (similar to current BPT limits) and numeric limitations on mercury, arsenic, selenium, and nitrate/nitrite as nitrogen
  • For oil-fired units and units with nameplate capacity of 50 MW or smaller, the BAT limitations on TSS would be equal to current TSS BPT’s
New Sources with Direct Discharges 

This category of sources is subject to New Source Performance Standards (NSPS) as follows: 

  • Fly/bottom ash transport and FGMC – zero discharge for all covered pollutants
  • FGD – numeric standards for mercury, arsenic, selenium, and TDS  
Existing Sources with Indirect Discharges (to POTWs) 

Pretreatment Standards for Existing Sources (PSES) apply to this category as follows: 

  • Fly/bottom ash transport and FGMC – zero discharge for all covered pollutants
  • FGD – numeric standards for mercury, arsenic, selenium, and nitrate/nitrite as nitrogen
New Sources with Indirect Discharges 

The established Pretreatment Standards for New Sources (PSNS) have been set to be equal to NSPS.

In accordance with rule provisions, effluent limitations will likely be incorporated in wastewater discharge permits at some point beginning on November 1, 2018 but no later than December 31, 2023 (the rule actually states that effluent limitations do not apply until a date determined by the permitting authority that is as soon as possible beginning November 1, 2018).