The U.S. Environmental Protection Agency (EPA) earlier this year proposed changes to the federal coal ash rule, saying it would eliminate requirements for onsite dry storage of coal ash, along with limiting environmental protections on large fill projects, except for those with what the agency calls “geologic vulnerabilities.” Under the original version of the rule, companies with fill projects larger than 12,400 tons had to ensure that the ash did not impact the soil, air, and water around the sites.
The power generation industry has said those changes could allow coal ash to be more easily recycled, opening more pathways for what’s known as “beneficial use” of ash, which includes the use of ash in construction materials such as concrete and wallboard. Environmentalists have said the proposal would lead to more untracked and unregulated coal ash. The EPA has been working with the utility industry since March 2018 to streamline the 2015-enacted Coal Combustion Residual (CCR) rule, which was issued after years of debate in the wake of large coal ash spills in Tennessee and North Carolina. The rule establishes technical requirements for CCR landfills and surface impoundments under subtitle D of the Resource Conservation and Recovery Act (RCRA), the nation’s primary law for regulating solid waste.
SCS Engineers closely follows developments relating to coal ash disposal, helping landfill operators, utilities, and others who deal with CCR meet the challenge of proper waste management as regulations evolve.
In addition to keeping up with rule changes, utilities are facing new challenges under the original CCR rules as time goes by, and CCR sites move through the regulatory timeline. Many utilities that began groundwater monitoring at CCR units under the rule in October 2017 and identified groundwater impacts are now entering the stage of remedy selection.
If groundwater monitoring shows that pollutants exceed groundwater protection standards (GWPS), then a response is required unless it can be shown that a source other than the CCR unit is responsible for the impacts, as documented in an Alternate Source Demonstration (ASD). The determination of what is best for a particular site is based on several factors and begins with what is known as an Assessment of Corrective Measures (ACM). The ACM is the first step in developing a long-term corrective action plan designed to address problems with pollutants in groundwater near areas of ash disposal. The ACM is pursuant to the EPA’s CCR rule.
“Obviously people are still looking at what things cost, but in our experience, working with utilities, the concern for the surrounding community and the environment is uppermost,” says Tom Karwoski, a vice president with SCS Engineers. Karwoski has 30 years of experience as a hydrogeologist and project manager, designing and managing investigations and remediations at existing and proposed landfills, as well as clean-ups of industrial, military, petroleum, and Superfund sites. Karwoski says his group has “no preconceived notions about what is best for all sites.”
Utilities working to satisfy requirements of the CCR rule have performed ACM and ASD projects, and several are moving into the “Remedy Selection” phase of the process. SCS Engineers is working with these utilities to determine the best remedies for CCR disposal, drawing on the company’s experience in providing solutions across the spectrum of waste management. SCS designs solutions for municipal solid waste (MSW)—in effect, trash and garbage, or what the EPA calls “everyday items such as product packaging, yard trimmings, furniture, clothing, bottles and cans, food, newspapers, appliances, electronics and batteries”—and also develops management programs for electric utility (EU) waste, such as CCR, which is far different in terms of scope and pollutants.
Eric Nelson, a vice president with SCS Engineers, one of the company’s national experts for electric utilities, and an experienced engineer and hydrogeologist, knows the challenges of establishing a successful program for managing CCRs. “The CCR rule quite literally borrows language from MSW rules; word for word in some instances. The stark difference, in my view, is the varied participation by regulators. In general, the states have not picked up the ball to oversee the rule as EPA has suggested they do, which is no small burden. However, many states had existing CCR management rules or have since enacted their own rules adding layers of regulation.” The EPA in June of this year supported a Georgia plan for CCR disposal, with EPA Administrator Andrew Wheeler saying, “EPA encourages other states to follow Georgia’s lead and assume oversight of coal ash management within their borders. EPA is committed to working with the states as they establish coal ash programs tailored to their unique circumstances that are protective of human health and the environment.”
Said Nelson: “My understanding was that when similar rules were introduced for MSW sites, the owner, their consultant, and a regulator [state or EPA] worked through the remedy selection process. There is no real-time regulatory feedback in many cases with the requirements in the federal CCR rule.”
Nelson is familiar with the process of establishing a program to manage CCRs. “The groundwater monitoring and corrective action portion of the CCR rule allows for specific timeframes for establishing a monitoring system, obtaining background samples, identifying statistically significant increases [SSI] in groundwater concentrations, assessing alternative sources of those SSI, completing assessment monitoring, and then assessing corrective measures for groundwater impacts above groundwater protection standards,” he says. “Stacking all of those timeframes onto one another has us where we are today [sites recently completing ACMs and working on remedy selection]. We are about to repeat this same cycle, starting with identifying SSIs, with groundwater monitoring of inactive surface impoundments that were previously exempt from groundwater monitoring under [rule section] 257.100, an exemption removed with previous rule revisions.”
At the moment, remedies for CCR units that have not already undergone closure will include some form of source control. The most likely controls include closure-in-place, sometimes called cap-in-place, or closure-by-removal of coal ash. Closure-in-place involves dewatering the impoundment—or converting wet storage to dry storage—stabilizing the waste, and installing a cover system to prevent additional water or other material from entering the impoundment. Closure-by-removal involves dewatering and excavating the CCR, then transporting it to a lined landfill.
In addition to these source control and closure strategies, remedies for groundwater impacts from CCR units might also include approaches from two other categories of corrective measure – active restoration and plume containment. The options available and those appropriate will depend on many site-specific factors including the size of the source, the groundwater constituents and concentrations, and the receptors at risk.
These factors, more remedies, and the selection process will be discussed in more detail as this blog series continues.
Mr. Karwoski has 30 years of experience as a hydrogeologist and project manager. He has designed and managed investigations and remediations at landfills and for industrial, superfund, military, and energy firms.
Eric J. Nelson, PE, is a Vice President of SCS Engineers and one of our National Experts for Electric Utilities. He is an engineer and hydrogeologist with over 20 years of experience. His diverse experience includes solid waste landfill development, soil and groundwater remediation, and brownfield redevelopment. He is a Professional Engineer licensed in Wisconsin and Iowa.
Mark Huber is a Vice President and Director of SCS’s Upper Midwest Busines Unit. He is also one of our National Experts in Electric Utilities. Mark has nearly 25 years of consulting experience in civil and environmental engineering. His experience working on a variety of complex challenges for utilities allows him to quickly identify key issues and develop smart, practical solutions. He also has expertise in urban redevelopment projects with technical expertise in brownfield redevelopment, civil site design, and stormwater management.
Solar Ready CCR Site Closures Help Energy Companies Move Toward a Sustainable Future
Electricity is the one big energy source that can be free of carbon emissions. You can make it from the sun. You can make it from the wind. Tap the heat of the Earth, hydropower. While all utilities are moving in a sustainable, environmentally friendly direction, Aliant Energy stands out for making progress and keeping rates reasonable for consumers.
At the recent USWAG Workshop on Decommissioning, Repurposing & Expansion of Utility Assets held October 2019, Eric Nelson presented on the opportunities for solar generation at closed CCR sites and provided an overview of civil and geotechnical considerations when redeveloping closed sites as solar generating assets. His presentation demonstrated these considerations through the use of a case study.
SCS Engineers has assisted Alliant Energy with the design and/or construction of multiple coal combustion residual (CCR) surface impoundment closures. Two of the completed closures are the former Rock River Generating Station in Beloit, Wisconsin, and the M.L. Kapp Generating Station in Clinton, Iowa.
Both sites were closed by incorporating Alliant Energy’s vision to create “solar ready” sites. The Rock River site is now home to just over 2 megawatts (MW) of solar photovoltaic (PV) generating capacity, which was developed on the footprint of the now-closed on-site landfill and ash ponds. Although no solar assets have been developed at the site, the M.L. Kapp ash pond closure represents another opportunity for Alliant Energy to repurpose a closed ash pond for clean power.
Two additional closure designs are in process that incorporates similar elements, making them available for future solar generating asset development.
Eric J. Nelson, PE, is a Vice President of SCS Engineers and one of our National Experts for Electric Utilities. He is an experienced engineer and hydrogeologist.