Coal Power Plant ELGs – U.S. EPA Forces Stricter Limits or Cease Firing Coal

Introduction

Coal fired power plants in their combustion process create waste ash which contains heavy metals and other pollutants. This ash makes its way into discharge wastewater ending up in the environment and impacting the health of humans and wildlife. The United States Environmental Protection Agency (U.S. EPA) has been regulating coal fired power plants wastewater discharge for the better half of a century to mitigate this. These restrictions, called effluent limitation guidelines (ELG), require power plants to use certain treatment technologies and follow numeric discharge limits. On April 25^th, U.S. EPA finalized a new set of ELGs which force coal power plants to abide by new and stricter limits or permanently stop burning coal. The new rule takes effect on July 8, 2024.

More stringent limitations for direct dischargers in the rule do not apply until a date determined by the permitting authority that is as soon as possible on or after July 8, 2024, but no later than December 31, 2029.

For indirect discharges, pretreatment standards are established that are directly enforceable and apply May 9, 2027.

The goal of these regulations is to reduce the introduction of heavy metals and other pollutants into the waters of the U.S (WOTUS). The intention of the regulation is to benefit disadvantaged, low income, and minority communities, which are most adversely impacted by coal power plants.

ELG Limits

The ELG focus on the following waste sources:

• Flue gas desulfurization (FGD) wastewater – wastewater from sulfur dioxide scrubbing
• Bottom ash (BA) transport water – water used to transport noncombustible residue
• Combustion residual leachate (CRL) – leachate water collected from coal combustion residual landfills
• Unmanaged CRL – CRL that is 1) determined by permitting authority to be a functional equivalent of direct discharges to waters of the U.S. or 2) CRL that mixed with groundwater before being discharged to waters of the U.S.

The following limits are imposed:

• A zero-discharge limitation for all pollutants in FGD wastewater, BA transport water, and CRL.
• Numeric limitations for mercury and arsenic in unmanaged CRL and for legacy wastewater discharged during the closure process if those surface impoundments have not commenced closure under the Coal Combustion Residuals (CCR) regulations as of the effective date of this rule.

To comply with the limits detailed above facilities may have to construct or modify existing treatment and/or process technologies with the following:

• Biological Reduction
• Membrane Filtration
• Spray or Thermal Evaporation
• Zero valent Iron
• Alternative BA transport such as conveyors or pressurized transport systems

Ceasing Coal Combustion

For plants unable or unwilling to meet these new limitations, the alternative the regulation gives is to cease coal combustion by December 31, 2028 or December 31, 2034. A Notice of Planned Participation must be submitted by June 27, 2023 to enroll in the cessation agreement. By opting into this cessation agreement, facilities choose to switch to fuels alternative to coal later in agreement with U.S. EPA that they will be subject to a more lenient category of ELGs as outlined below:

• Coal combustion cessation by December 31, 2028:
  • Surface impoundments are the required technology
  • U.S. EPA determined other technologies would disrupt the coal cessation process

• Coal combustion cessation by December 31, 2034:
  • 2020 rule requirements for FGD wastewater and BA
  • Pre-2015 best available technology requirements for CRL, chemical precipitation for CRL after coal combustion cessation

Conclusion 

The new ELGs are a part of the Biden-Harris administration’s pollution reduction measures and are forcing coal burning power plants to act now. These limits, while strict, have been in line with other recent measures such as the updated National Ambient Air Quality Standards for particulate matter, and maximum contamination levels for polyfluorinated substances. The coal power plant ELG rule was published in conjunction with similar rules affecting power plants such as reduced mercury and air toxic standards, and a Resource Conservation and Recovery Act rule which requires management of coal ash at inactive power plants.

If you need help evaluating your compliance options and strategies, please do not hesitate to reach out to an ALL4 consultant. Evan Mia can be reached at emia@all4inc.com. Be sure to keep an eye out for ALL4 articles which give timely updates and notices for regulatory changes.