CCR impoundments

May 2, 2024

SCS Engineers Power Sector Compliance
EPA announces compliance changes under the Clean Air Act, Clean Water Act, and the Resource Conservation and Recovery Act impacting Power Sector operations and compliance reporting.


EPA announces final rules intended to reduce pollution from fossil fuel-fired power plants, which the Agency claims will not disrupt reliable electricity delivery. These rules, finalized under separate authorities including the Clean Air Act, Clean Water Act, and Resource Conservation and Recovery Act, aim to reduce climate, air, water, and land pollution from the power sector.

The power sector has been investing long-term to transition to a clean energy economy based on rule changes like those recently announced by the EPA. This technical compliance alert summarizes four key rule changes, including:

  • Mandate that existing coal-fired and new natural gas-fired power plants that plan to run long-term and all new baseload gas-fired plants control 90 percent of their carbon pollution.
  • Tighten the Mercury and Air Toxics Standards (MATS) for coal-fired power plants by reducing the emissions standard for toxic metals by 67 percent and finalizing a 70 percent reduction in the emissions standard for mercury from existing lignite-fired sources.
  • Reduce pollutants discharged through wastewater from coal-fired power plants by more than 660 million pounds per year, ensuring cleaner water for affected communities, including communities with environmental justice concerns.
  • Require the management of coal ash placed in unregulated areas at the federal level, including previously used disposal areas that may impact groundwater.


Clean Air Act – NSPS
40 CFR Part 60

  • EPA is repealing the Affordable Clean Energy (ACE) Rule, adopted during the Trump Administration to replace the Clean Power Plan (CPP) adopted during the Obama Administration to regulate GHG emissions. The D.C. Circuit Court vacated the ACE in 2021, and the CPP was struck down by the U.S. Supreme Court in 2022.
  • EPA has determined that under the New Source Performance Standards (NSPS), the best system of emission reduction (BSER) for the longest-running existing coal-fired and new base load combustion turbines is “a proven add-on control technology—carbon capture and sequestration/storage (CCS).”
  • For existing coal-fired electric generating units (EGUs) that intend to operate on or after January 1, 2039 (i.e., “long-term” units), and for new base load combustion turbine units, EPA will impose a numeric emission rate limit based on the application of CCS with 90% capture by January 1, 2032.
  • In its press release, the EPA states that tax incentives from the Inflation Reduction Act allow companies to help offset the cost of CCS.
  • Edison Electric Institute, an industry trade group, says, “CCS is not yet ready for full-scale, economy-wide deployment, nor is there sufficient time to permit, finance, and build the CCS infrastructure needed for compliance by 2032.” The courts will likely have to decide (again).
  • EPA is finalizing revisions to the NSPS that do not include CCS for GHG emissions from other types of EGUs. States will have two years to submit State Implementation Plans (SIPs) for the new rules. SIPs must reflect meaningful engagement with stakeholders and may incorporate several provisions that the EPA says will encourage flexibility and help assure the electric grid’s reliability.

EPA Fact Sheet:


Clean Air Act – MATS and TRI

 The EPA is updating the Mercury and Air Toxics Standards (MATS) for coal- and oil-fired power plants to reduce hazardous air pollutant (HAP) emissions, with standards reflecting the latest advancements in pollution control technologies.

The final rule reduces the mercury emissions limit last set in 2020 by 70 percent for lignite-fired units and reduces the filterable particular emissions limit (a surrogate for other toxic metals) by 67 percent for all coal plants—while also requiring the use of continuous emission monitoring systems to provide real-time, accurate data to regulators, facility operators, and the public to ensure that plants are meeting these lower limits and that communities are protected year-round from pollution exposure.

For more information:


Clean Water Act – Effluent Limitations Guidelines (ELG)
40 CFR Part 423

Wastewater discharge standards that apply to coal-fired power plants under the Clean Water Act are intended to reduce the possibility of toxic metals and other pollutants in wastewater entering lakes, streams, and other water bodies.

EPA’s final rule establishes technology-based discharge standards—known as Effluent Limitation Guidelines and Standards (ELGs)—that apply to four types of wastewater:

  • Flue gas desulfurization wastewater,
  • Bottom ash transport water,
  • CCR leachate,
  • “Legacy wastewater” stored in surface impoundments (for example, coal ash ponds).

Recognizing that some coal-fired power plants are in the process of closing or switching to less polluting fuels such as natural gas or renewable natural gas, the regulation includes flexibilities to allow these plants to continue to meet the 2015 and 2020 regulation requirements instead of the requirements contained in this final regulation. The EPA is creating a new subcategory for energy-generating units (EGUs) that permanently cease coal combustion by 2034.

EPA Fact Sheet:


RCRA – Coal Ash/CCR Disposal and Impoundments
40 CFR Part 257

Under the Resource Conservation and Recovery Act, EPA is finalizing a rule for controlling and cleaning up contamination from the disposal of coal combustion residuals (CCR), or coal ash. The Agency is finalizing regulations for managing coal ash at inactive surface impoundments at inactive power plants and historical coal ash disposal areas. Inactive coal ash surface impoundments at inactive facilities are called “legacy CCR surface impoundments.”

This final rule extends a subset of EPA’s existing CCR requirements to these historic disposal units to remediate contamination and prevent further impacts. These requirements apply to all active and inactive facilities with legacy CCR surface impoundments. EPA is strengthening established groundwater monitoring, corrective action, closure, and post-closure care requirements for CCR management units (regardless of how or when that CCR was placed) at regulated facilities.

This rule becomes effective six months after publication of the final rule in the Federal Register. The compliance deadlines in the final rule provide additional time beyond the effective date for facilities to comply with certain technical criteria based on the amount of time EPA projects that facilities need to complete them, such as installing a groundwater monitoring system or developing a groundwater sampling plan and analysis program.

EPA Fact Sheet:

Pre-publication Version of the Hazardous and Solid Waste Management System: Disposal of Coal Combustion Residuals from Electric Utilities; Legacy CCR Surface Impoundments Rule:


Power Sector Compliance, Operations, and Reporting Resources:



Posted by Diane Samuels at 6:00 am

March 2, 2020

CCR – Disposal Regulation Revisions & Permitting Program by the U.S. Environmental Protection Agency moves forward on two matters that proposed to revise its 2015 solid waste regulations for the disposal of coal combustion residuals.

On February 19, 2020, EPA announced what it said is the last of planned actions to implement the Congressional mandates, respond to petitions, address the results of litigation, and apply lessons learned to ensure smoother implementation of the regulations. In a rulemaking entitled “A Holistic Approach to Closure Part B,” EPA proposed the following revisions:

  • Procedures to allow facilities to request approval to use an alternate liner for CCR surface impoundments;
  • Two co-proposed options to allow the use of CCR during unit closure;
  • An additional closure option for CCR units being closed by removal of CCR; and
  • Requirements for annual closure progress reports.

One of the proposed options for allowing the use of CCR for closure activities would allow coal ash to be moved between units at the same facility and consolidated at impoundments that are scheduled for closure. The second option would allow utilities to beneficially use coal ash in disposal unit closure activities.

Under the proposed rule, utilities would need to submit an alternative liner demonstration within 13 months of the final rule, with the possibility of extensions. The EPA noted there would likely be few basins able to meet the alternative liner requirements.

The proposal would also allow utilities to continue disposing ash into some ponds even after the pond has been scheduled for closure. Ponds will still be able to take in ash if the ash remains under a certain volume — and this includes ponds located in unstable areas, such as in a seismic zone or within five feet of a waterway.

EPA will seek comment on this proposal during a 45-day public comment period that will commence when it is published in the Federal Register. EPA will also hold a virtual public hearing on the proposal on April 9, 2020.


On February 20, 2020, EPA’s previously announced proposed rule to establish a Federal CCR Permitting Program was published in the Federal Register. The creation of a federal permitting program for coal ash disposal regulations was required by Congress in the 2016 Water Infrastructure Improvements for the Nation (WIIN) Act, which shifted enforcement authority for EPA’s disposal standards from citizen lawsuits to state environmental regulators. The federal permit program is intended for use in states that do not seek EPA approval for their own programs and for use in Indian Country.

The proposed federal program includes electronic permitting and sets requirements for permit applications, content and modification, as well as procedural requirements.

EPA will accept public comment on the proposed program until April 20, 2020. The agency will also hold a virtual public hearing on the matter on April 15, 2020.

Media reports of the announcements included coverage by The Hill, E&E News, Utility Dive, Phoenix Newsletter, and a pair of stories by Bloomberg.


Coal Combustion Residuals solutions, case studies, articles are here, including information about coal ash landfills, support, and closures.




Posted by Diane Samuels at 6:00 am

February 13, 2017

At the upcoming USWAG CCR Workshop Feb 22-23 in Arlington, VA, Steve Lamb and Floyd Cotter of SCS Engineers will present a session about the advantages and disadvantages of emerging alternative capping options, and how different regulatory agencies are viewing these options.

About this Session: Traditional final cover and capping design for coal combustion residual (CCR) surface impoundments and landfills have included compacted soil liner, geomembrane liner, drainage layer, and a vegetative soil cover. But coal-fired plants oftentimes don’t have the large volumes of soil that it takes to implement these options.

Alternative capping options have recently emerged in the industry such as exposed geomembrane liners or synthetic turf/geomembrane liner systems. Some of these alternative capping options have many advantages over their traditional counterparts. These advantages include faster installation times, minimal need for soil, improved storm water quality, and reduced maintenance and post-closure costs. For surface impoundments, alternative capping designs can also greatly reduce the amount of disturbance of the existing CCR material within the impoundment.

About Steve Lamb: Steve Lamb, PE provides SCS with over 27 years of experience in solid and hazardous waste management, environmental engineering, civil engineering, hydrology and hydraulics, landfill engineering, remedial design, and regulatory compliance. Mr. Lamb is a Vice President and director of SCS’s Charlotte, NC office.

About Floyd Cotter: Floyd Cotter specializes in solid waste management projects. His project work involves all areas of solid waste management including planning, permitting, transportation, landfill design, construction, and monitoring. Mr. Cotter is also experienced in general civil engineering, construction oversight, environmental site assessments, closure and post-closure plans, and permit and contract document preparation.

Posted by Diane Samuels at 3:00 am