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Managing CCRs

This ash basin at the Meramec Energy Center closed in the spring of 2018.
This ash basin at the Meramec Energy Center closed in the spring of 2018.

The Coal Combustion Residual (CCR) Rule contains technical standards for the design, operation and closure of landfills and basins located at coal-fired energy centers. Through this rule, EPA regulates CCR as solid waste under the Resource Conservation and Recovery Act (RCRA). RCRA requires that CCR facilities operate in a manner that presents "no reasonable probability of adverse effect on health or the environment." In 2016, Congress passed legislation that authorized states to develop CCR programs and adopt, as appropriate, site specific criteria. In 2018 and in recognition of this congressional action, the Missouri General Assembly passed legislation authorizing the Missouri Department of Natural Resources (MDNR) to develop and submit a state CCR program to EPA for approval.

Also in 2018, EPA proposed revisions to the CCR Rule (Phase-One Rules) to address, in part, Congress's changes to RCRA and allow state directors to use risk-based processes similar to other existing solid waste program. Both the State of Missouri and Ameren filed public comments that support EPA's proposed changes. Copies of those comments can be accessed here.

EPA finalized the first phase of these CCR-related changes in July 2018, and the final phases are expected by summer 2019. Until a state CCR program is finalized and approved by EPA, MDNR can utilize its state-level cleanup program to approve closure and corrective measures at Ameren's ash basins.


Closure Update

Fall 2020

Ameren Missouri is making rapid progress on safely closing ash basins at three of our four energy centers well ahead of regulatory requirements. Extensive construction activities have continued at all sites during the pandemic with construction schedules remaining largely intact. Crews can work safely while maintaining health protocols.

In 2019 alone, approximately 120 billion gallons of water was saved from coal plant and ash basin closures. Ameren Missouri is also recycling a majority of ash for beneficial use, primarily in cement and concrete production.

Crews finish covering the protective liner with turf and sand at Rush Island Energy Center. The cover is contoured for controlled rainwater drainage.
Crews finish covering the protective liner with turf and sand at Rush Island Energy Center. The cover is contoured for controlled rainwater drainage.
Weighted bags temporarily hold down the turf until sand is swept in, anchoring the turf to the liner below.
Weighted bags temporarily hold down the turf until sand is swept in, anchoring the turf to the liner below.

Our robust monitoring network consists of more than 250 wells around the four facilities. They track groundwater quality and measure water levels to help ensure the area continues to be protected. There continues to be no risk to public health and the environment. Extensive, expert-led reporting, stretching back to 2012, continues to demonstrate Ameren's safe handling of material. Those studies offer definitive proof that there is no off-site impact to drinking or surface water. In addition to our current network, we will be installing additional groundwater wells at Rush Island that will be used as part of an industry-leading groundwater treatment system pilot project. The Missouri Department of Natural Resources has given its preliminary approval, and the system will become operational once a final permit is issued later this year or early in 2021.

Construction updates include:

  • A virtually impermeable protective liner is now installed over nearly all the basins.
  • More than half of the installed liner is covered by a final top layer, either topsoil or turf.
  • Recycling more than 70% of current ash production as a result of energy center upgrades.

Answers to Customer Questions

Ameren has been safely operating CCR storage facilities for decades. Below are answers to some frequently asked questions from the public about the comprehensive steps Ameren has taken to manage CCRs.

What is Ameren doing to close the ash basins?
Ameren is implementing a comprehensive plan to safely and responsibly close ash basins that exceeds requirements created by the Obama Administration’s Environmental Protection Agency (EPA) in 2015. These EPA regulations require Ameren to close CCR basins and develop steps to address any impacts to groundwater in the communities where we work and live.

Basins can be closed by either placing a cover system over the top, or by excavating them by dredging out the material. The EPA has long maintained it does not have a preference on closure methods, both of which are effective in protecting the environment. The agency expects most CCR basins across the country will close via installation of a cover system. Ameren has thoroughly explored and used experts to help assist, on how to best design and close the basins and limit impacts on the communities we serve and call home. As a result of that extensive analysis, Ameren plans to close the basins by installing a cover system that exceeds regulatory requirements. Safe, responsible closure using this method is the most efficient path to achieve the groundwater protection standards set under the federal rule. Ameren Missouri's plans are summarized in the Remedy Selection Report (PDF).

What happens next?
Excess water is removed from the basins and the ash will be compacted, graded and sloped to permanently shed water. After that, an engineered capping system, far stronger than regulations require, will be constructed over the top of the basins and the riverside embankment walls armored with rock. This system will take approximately two years to construct and isolate the ash from infiltration. Precipitation will be routed to newly-constructed storm water basins. The limited groundwater impacts localized to Ameren property will diminish over time, and experts are evaluating methods to accelerate this process. Further details are available here.

Are there impacts on public health?
No. As demonstrated in numerous reports over many years, expert sampling results demonstrate that Ameren's CCR units do not impact public drinking water sources that draw from the Meramec, Mississippi and Missouri Rivers. Additional expert testing of groundwater used by drinking water wells near energy centers also show no impact.

Are CCR basins stable and safe?
Yes. Energy center personnel inspect the basins weekly and annual inspections are conducted by specially trained dam safety engineers. Because of their construction and design, the CCR basins at Ameren’s energy centers are in no danger of collapse, as has happened elsewhere. The basins have thick walls and are constructed to withstand up to an 8.0 magnitude earthquake. Even in cases of extreme flooding, as seen in the spring of 2019, the basins performed as designed.

What studies have been done?
For the past several years, Ameren has commissioned dozens of environmental studies by certified toxicologists and other experts in their fields of study. These ongoing inspections of groundwater, drinking and surface water conclude there is no risk to public health. Additional studies, posted to this website, looked at excavation and transportation issues associated with basin closure methods.

How has the community been involved in the process?
Ameren held four public meetings, one each near the four energy centers in May 2019. Attendees asked questions and left written comments. Additional comments were received via email. Ameren notified media outlets and posted information about the public meetings on this website.

More information is available under each section header at the top of this page, or in the public meeting and technical details response (PDF).

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