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EPA Provides New Coal Combustion Residual Expectations

Graham Crockford & Greg Tieman | October 6, 2022

Coal combustion residuals (CCRs), also known as coal ash, are byproducts created during coal-fired power plant operations. These waste materials contain metallic compounds and can be disposed of in various ways, such as surface impoundments or landfills. Recent communications from the Environmental Protection Agency (EPA) indicate a shift towards stricter CCR compliance, with potential implications for the entire regulated community. With new insight into groundwater monitoring and corrective action, there are significant implications that may affect the entire regulated community. Taking steps to understand these potential implications/risks and identifying solutions now can help strengthen your position for future CCR compliance and ongoing facility operations.

Regulatory Overview

On July 12, 2022, the EPA published the Proposed Conditional Approval of Alternative Closure Deadline (Proposed Conditional Approval) for two of the 57 Part A Applications. Recall that Part A Applications were submitted to the EPA to extend the cease receipt date of April 11, 2021, for unlined surface impoundments to receive CCR and non-CCR wastewaters. Both Proposed Conditional Approvals are out for Public Comment and the EPA extended the Public Comment period to September 26, 2022. For both Proposed Conditional Approvals, EPA is proposing to find that the facilities are not in compliance with requirements of the Code of Federal Regulations (CFR), 40 CFR, Part 257 CCR regulations (Rule), including noncompliance with groundwater monitoring requirements for both facilities and noncompliance with correction action requirements for one of the facilities. The EPA is proposing to conditionally approve the requests for extension for both facilities because it has determined that conditions can be developed to address the identified noncompliance before the date of the requested extension.

In addition to the Proposed Conditional Approvals described above, the EPA previously issued Proposed Determinations to four of the 57 Part A Applications on January 11, 2022. For three of the four Part A Applications, the EPA proposed to deny the extension to continue receiving CCR and non-CCR wastewaters and instead issue a cease receipt of waste date of 135 days after the final determination. At the same time, the EPA also issued Compliance Letters to four other facilities regarding their compliance with the Rule.

In addition to facilities potentially closing due to a lack of disposal capacity (following denial of the Part A Applications/Alternate Closure Deadlines), the potential implications of the EPA’s interpretations of the Rule provided in the Compliance Letters and the Proposed Conditional Determinations focused on groundwater monitoring and corrective action requirements under the Rule will be significant.

Key Closure/Groundwater and Other Compliance Issues

As provided in the EPA’s January 11 Compliance Letters and/or the July 12 Proposed Conditional Approvals, the EPA’s key policy interpretations and existing Rule compliance expectations related to groundwater and closure issues include the following:

  • Closure plans must detail how the closure standards will be met under the Rule, considering the following interpretations:
    • CCR units (impoundments and landfills) cannot close in-place (CIP) with CCR in contact with groundwater.
    • Free liquids to be addressed prior to CIP include both freestanding liquids (e.g., surface water), as well as all separable porewater, including sluiced water and groundwater.
    • Infiltration includes potential vertical infiltration at ground surface, as well as horizontal and upward infiltration from the base, including groundwater.
    • Schedule changes, design changes, etc., need to be updated in the closure plan and reposted on the website with amendments made 60 days ahead of a planned change.
  • Deficiencies with the groundwater monitoring systems, including well locations, number of wells, spacing, etc., must be corrected, and an accurate characterization of hydrogeologic conditions (i.e., a well-developed Conceptual Site Model (CSM) based on site-specific data) is necessary to properly address these requirements. A justification of the use of the minimum of one upgradient and three downgradient wells should be justified.
  • PE certification of the monitoring network requires an evaluation of site-specific conditions and an explanation as to how the monitoring network meets the requirements, including justifying and updating documents when changes are made to the monitoring network.
  • Deficiencies with the annual Groundwater Monitoring and Corrective Action (GWMCA) Reports, and the lack of appropriate information therein to support should be justified.
  • Deficiencies with Alternate Source Demonstrations (ASD’s), including the lack of site-specific facts and data support the ASD (insufficient lines of evidence) should be justified.
  • Monitored natural attenuation (MNA) for inorganic constituents (e.g., metals) cannot rely on dispersion and dilution as a primary MNA mechanism.

In addition to the closure and groundwater regulatory interpretations, EPA also noted the following:

  • Units closing for cause (e.g., unlined surface impoundments) cannot place CCR in the unit, even if for beneficial use.
  • Placement of CCR, including for beneficial use, in an inactive unit not previously subject to the Rule, makes the unit active and subject to the Rule.
  • Legacy impoundments (inactive impoundments at inactive sites) may become “existing CCR surface impoundments”, per the regulatory definition, and subject to the closure requirements if they receive CCR after the effective date of the Rule (October 19, 2015).
  • Impoundments that closed prior to the Rule and were not subject to the regulations, but still contain or impound liquid, including groundwater in contact with CCR, may be considered an “inactive impoundment” and subject to the Rule.
  • Concrete settling tanks may be considered CCR surface impoundments, particularly if they are sub-grade, if they are considered to be in a constructed depression, and they must meet the requirements of the Rule, including groundwater monitoring requirements.
  • The calculation of availability of alternate on-site disposal capacity must detail why the ponds requesting extension must all continue to operate and whether non-CCR waste streams could be diverted to other ponds allowing some closure of unlined ponds.
  • Confirmation from Regional Transmission Operators (RTO) may be required by conducting a formal reliability assessment related to planned outage requests for the utility, to justify the utility’s argument that denying the pond closure extension will adversely affect the power generation grid.

Action Plan for the Regulated Community

Because the EPA Part A Application, Compliance Letter comments, and Proposed Conditional Approvals reference the regulatory citations under the Rule, all regulated facilities/units (and many currently unregulated units) could become subject to the final determinations.

Several of the EPA comments highlight the importance of hydrogeological site characterization and making sound judgements and conclusions backed by supporting data. Many of these interpretations, especially those regarding closure and groundwater issues, are inconsistent with the regulated community’s understanding of the CCR requirements, and in some cases conflict with the original Rule.

While these initial determinations will be worked out through the Public Comment period, the EPA’s final determinations, and anticipated future litigation, regulated entities may wish to consider preemptive positioning to evaluate their potential risk/liability. Some of these implications (e.g., CIP with CCR in contact with groundwater) can have significant monetary and operational impacts for past, ongoing, and future pond and landfill closures, including plant closures, as well as consideration for future site use and transactional challenges.

There are several key areas and practical solutions that can be evaluated/implemented to identify potential risks and strengthen your position in demonstrating compliance with the Rule, including:

  • New CCR Units: Identify potential closed units or legacy ponds that could become subject to the Rule, based on the above EPA interpretations.
  • Document Audit: Evaluate your CCR Website to ensure all documents required by the Rule are posted and have been updated in accordance with the Rule, especially the GWMCA Reports, Closure and Post Closure Plans.
  • Risk Analysis and Data Gaps: Review existing documents through the EPA’s lens/comments, especially ACMs, ASDs and lines of evidence, GWMCA’s Reports, Closure/Post Closure Plans, selected groundwater corrective actions to evaluate potential shortfalls, potential corrective actions and ease of implementation, and associated costs.
  • Independent Third-Party Review of Key Groundwater and Closure Plan Issues:
    • Groundwater Monitoring Plan: Evaluate the basis for your Groundwater Monitoring Plan (GMP), including well locations, number of wells, etc., and ensure you have a solid justification, including a robust CSM that demonstrates the site geology and groundwater flow is well-understood, to support the GMP. The level of effort/justification will depend on many site-specific factors, including pond size, hydrogeologic intricacy, other potential sources, single or multiunit monitoring, etc.
    • Data Collection: Research and compile groundwater data at the power station, evaluate trends in that data and compare to data trends from existing CCR units.  Should additional monitoring be conducted for data gaps?
    • Data Management: Consider incorporating digital enhancements to improve data collection and a platform to manage and protect data assets that can also facilitate efficiencies in data evaluation.
    • Corrective Action: If you have proposed MNA as part of your groundwater corrective action, evaluate the basis and justification of using MNA, and whether it relies primarily on dispersion and dilution to mitigate groundwater impacts.
    • Multi-Unit Statistically Significant Increases (SSI) or Statistically Significant Levels (SSL): If you have triggered assessment monitoring or corrective action due to an SSI or SSL, respectively, for a multi-unit unit, ensure that you have initiated the same for all units covered under the monitoring system.
    • Closure Plans: Evaluate your closure methodology and closure/post-closure plan considering the EPA’s interpretations, especially CIP if ash is in contact with groundwater. This may include closure by removal costs and associated issues, pore water/groundwater dewatering costs and use of engineering controls to address groundwater/infiltration during CIP and long-term post closure. This may include modeling to estimate historical (i.e., pre-pond construction groundwater levels) and post-closure groundwater levels to assist in engineering control evaluations.

Next Steps

It will likely be many months before there is resolution of these issues. In the interim, regulated entities should consider taking a fresh, possibly independent look at existing and forthcoming facility compliance given the EPA’s interpretations and consider adjustments to enhance their position. Understanding potential risks and solutions can assist power generators in their long-term compliance plan and planning of facility operations, including closure and/or redevelopment.

Graham Crockford, VP

Graham has over 32 years of experience in the fields of consulting, environmental engineering, geology, and hydrogeology. He currently serves as a Unit Leader for TRC’s Environmental, Construction, and Remediation business, where he drives TRC’s strategic direction to serve our client and business goals. With decades of experience working with legacy coal-fired power generation, his focus is also directed to support our clients achieve their renewable energy and decarbonization goals.  In this role, he fosters the connection of various TRC disciplines, and also engages in quality assurance, quality control and client experience.  He also serves as a Client Services Manager/Project Manager for TRC’s utility and industrial clients. Graham has a long history with the liquid/solid waste/CCR industry, including active-life and post-closure care. He has extensive experience in landfill permitting, wetland mitigation, and construction/operations. He also served as a program manager for a regional waste management firm for 4 years where he was responsible for implementing groundwater protection and compliance programs for over 12 TSDFs across the US. In the early 1990s Graham served on Michigan Waste Industry Association’s technical standards subcommittee providing advocacy and industry perspective during development of Michigan’s Part 115 Solid Waste statute/rules in response to Subtitle D. Contact him at

Greg Tieman, L.R.S.

Greg has over 30 years of experience in environmental consulting. His qualifications include extensive hands-on planning, field investigation and construction management, design, permitting, cost estimating, and project management. Greg’s background includes performing extensive services for coal-fired power plants in the southeastern United States and implementation of the Coal Combustion Residuals (CCR) Rule. He delivers services including regulatory support, strategic planning, hydrogeological investigations, feasibility studies, and preparation of Annual Groundwater Monitoring and Corrective Action reports and Alternative Source Demonstrations (ASDs). Contact Greg at

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