ENVIRONMENT
Disposal of Coal Combustion Residuals (CCR)
Summary of the Issues
Coal Combustion Residues (CCRs) may be generated wet or dry, and some CCRs are dewatered while others are mixed with water to facilitate transport (e.g., sluiced). Coal ash is stored in landfills and surface impoundments also called ponds. Landfills and ash ponds may or may not be lined with synthetic and natural clay barriers. The U.S. Environmental Protection Agency (EPA) determined that improperly constructed or managed coal ash disposal units have been linked to cases of harm to surface or ground water or to the air. Many of the coal ash ponds in the US are unlined. There are 735 active coal ash ponds in the US. The 2015 CCR Final Rule addressed the risks from the disposal of CCRs. These risks are leaking of contaminants into groundwater, the blowing of contaminants into the air as dust, and the catastrophic failure of coal ash surface impoundments (ponds). See U S EPA regarding the disposal of coal combustion residues (CCR) and effluent limitations guidelines (ELG).
On April 17, 2015, the EPA promulgated national minimum criteria regarding the disposal of coal ash into existing and new CCR landfills and existing and new CCR surface impoundments (storage ponds). This is known as the 2015 CCR Final Rule. This was applied to existing and new coal ash sites, but exempted landfills that had already closed. The CCR Rule did not require those landfills to disclose their liner status. Inactive surface impoundments at closed power plants were also exempt from this rule.
On August 21, 2018, the U.S. Court of Appeals for the D.C. Circuit (USWAG decision) vacated provisions that allowed unlined impoundments to continue receiving coal ash unless they leak, and vacated the EPA provision that classified “clay-lined” impoundments as lined. This court also vacated provisions that exempted inactive ( legacy) surface impoundments at inactive power plants from regulation.
This new rule (effective 2020) finalizes regulations, proposed on December 2, 2019, to implement the court's vacatur of the 2015 provisions. In addition, EPA is establishing a revised date by which unlined surface impoundments must cease receiving waste and initiate closure, following its reconsideration of those dates in light of the court decision. See the National Law Review for deadline dates. Lastly, EPA is finalizing amendments proposed on August 14, 2019, to the requirements for the annual groundwater monitoring and corrective action report and the requirements for the publicly accessible CCR internet sites. See Federal Register.
On May 8, 2024 The US EPA announced final changes to CCR regulations regarding inactive (legacy) surface impoundments at inactive electric power plants. This is known as the Legacy CCR Rule. Many of these older impoundments were built unlined and unmonitored. The Legacy CCR Rule will go effective November 2024 and it applies to CCRMUs (CCR management units) that exceed 1000 tons. However Facility Evaluation Reports (FER) must be written even for CCRMUs of 1-1000 tons.
UPDATES
The EPA on November 17, 2022 denied a request by American Electric Power to continue dumping coal ash from the Gavin Plant (Cheshire OH) into unlined storage ponds. This is the first time such an order transpired.
The US EPA approved Oklahoma( 2018), Georgia(2019), Kansas, and Texas(2020) coal ash disposal permit programs. These four states are the only states that have permission from the US EPA to independently administer their own program for disposal of CCR. Missouri and Alabama were denied approval. Currently 20 states are working with the US EPA.
Alabama: State regulators have approved Alabama Power's closure of the Barry coal ash pond near Mobile AL. In September 2023, the EPA denied state approval of Alabama Power's proposal to continue to dispose of coal ash in unlined ponds near waterways.
As of July 1019, Illinois requires new ash disposal procedures. The law directs the Illinois EPA to write the state’s new coal ash rules within eight months. All unlined coal ash pounds are to be closed as of April 2021. The Illinois Pollution Control Board will then finalize the proposed rules. The Illinois Pollution Control Board is also addressing old unconsolidated coal ash fills and temporary storage piles of coal ash. Both agencies are required to accept public comment before the rules are finalized.
North Carolina forced the closure of all unlined coal ash ponds. North Carolina instructed Duke Energy to excavate coal ash ponds at six sites. Duke Energy estimates it will cost $8-$9 billion to comply with North Carolina law.
Louisiana: Cleco submitted requests for more time for all three of its coal facilities: Big Cajun II in New Roads near Baton Rouge, Rodemacher near Alexandria and Dolet Hills in Mansfield. The company has pledged to close the 66-acre Big Cajun II pond, adjacent to the Mississippi River, and the 45-acre Rodemacher pond by Oct. 17, 2028. It has promised to close its coal-fired units at Rodemacher by that same date, while closing the unit at Big Cajun II in April 2025. At Dolet Hills, Cleco said it would close its two 33-acre ponds by Oct. 17, 2023, and cease burning coal at the same time. It plans to close all of its ponds in place rather than transfer the waste to another site, stating that no alternative disposal options for the coal slurry were viable.
Virginia mandates that Dominion Energy remove ash from ponds to landfills.
History of CCR Disposal
CCRs can be disposed in off-site landfills, or disposed in on-site landfills or surface impoundments. In 2012, approximately 40 percent of the CCRs generated were beneficially used, with the remaining 60 percent disposed in surface impoundments and landfills. Of that 60 percent, approximately 80 percent was disposed in on-site disposal units. CCR disposal currently occurs at more than 310 active on-site landfills, averaging more than 120 acres in size with an average depth of over 40 feet, and at more than 735 active on-site surface impoundments, averaging more than 50 acres in size with an average depth of 20 feet.
A surface impoundment failure occurred at TVA's Kingston Fossil Plant in Harriman, Roane County, Tennessee in December 2008 (releasing 1.1 billion gallons of coal ash slurry). This retention wall (dike) failure destroyed many properties, contaminated the Clinch River and cost the TVA one billion dollars over seven years.
In Feb. 2014, 39000 tons of coal ash spilled (from a broken pipe) into the Dan River from a coal ash containment pond at Duke Energy's plant in Eden, North Carolina. In September 2018, Hurricane Florence unleashed flooding at coal ash disposal ponds alongside Duke Energy’s L.V. Sutton power plant in Wilmington, NC, spilling coal ash into the nearby Cape Fear River. The company at one point estimated that flooding washed away the equivalent of more than 150 dump trucks full of coal ash.
In June 2019, the Illinois Pollution Control Board ruled that Waukegan Generating Station violated environmental regulations and was responsible for groundwater contamination from its coal ash ponds.
In March 2022, NIPSCO settled with the US EPA to do a $12 million cleanup of coal ash sites in Pines, Indiana (a million tons were landfilled there in close proximity to the town's aquifer.) Indiana also has the most ash impoundments or ponds (80) in the US.
In July 2024, one million gallons of coal ash water were released from an underground pipe break which was siphoning off the top of an old coal ash pound. This water reached a nearby lake. This occurred at the Boswell Energy plant in Cohasset MN.
Improperly constructed or managed coal ash disposal units have been linked in cases to harm to groundwater, and this final rule addresses the risks identified in these cases -- leaking of contaminants into groundwater -- by adding new requirements for coal ash surface impoundments and landfills including:
Groundwater monitoring around surface impoundments and landfills;
Liner requirements for new surface impoundments and landfills to protect groundwater;
Groundwater cleanup from coal ash contamination;
The closure of unlined surface impoundments that are polluting groundwater;
The closure of surface impoundments that fail to meet engineering and structural standards or are located too close to a drinking water source;
Restrictions on the location of new surface impoundments and landfills so that they cannot be built in sensitive areas such as wetlands and earthquake zones; and
Proper closure of all surface impoundments and landfills that will no longer receive CCRs.
The 2015 CCR Final rule also establishes liner design criteria to help prevent contaminants in CCRs from leaching from the CCR unit and contaminating groundwater. All new CCR landfills, new CCR surface impoundments, and lateral expansions of CCR units must be lined with composite liner, which is a liner system consisting of two components – a geomembrane and a two-foot layer of compacted soil – installed in direct and uniform contact with one another. The final rule allows an owner or operator to construct a new CCR unit with an alternative composite liner, provided the alternative composite liner performs no less effectively than the composite liner.
In addition, new landfills are required to operate with a leachate collection and removal system which is designed to remove excess leachate that may accumulate on top of the composite (or alternative composite) liner. Existing CCR landfills are not required to close or retrofit with a composite (or alternative composite) liner and a leachate collection and removal system. These existing CCR units can continue to receive CCRs after this rule is in effect; however, the CCR units must meet all applicable groundwater monitoring and corrective action criteria to address any groundwater releases promptly.
Existing CCR surface impoundments can also continue to operate as designed. However, if the existing CCR surface impoundment was not constructed with a composite (or alternative composite) liner or with at least two feet of compacted soil with a specified hydraulic conductivity, the rule may require the unit to retrofit or close. If such a CCR surface impoundment detects concentrations of one or more constituents listed in 40 CFR Part 257 - Appendix IV at statistically significant levels above the groundwater protection standard established by the rule, the CCR unit must retrofit or close.
The Beneficial Use of Coal Fly ash
The 2015 CCR Rule does not regulate CCR that are beneficially used. It established a definition of “beneficial use of CCR” to distinguish between beneficial use and disposal. Beneficial Use under the Final CCR Disposal Rule is the recycling or reuse of coal ash in lieu of disposal. For example, beneficial use of encapsulated CCR is an important ingredient in the manufacture of concrete and wallboard, and EPA supports the responsible use of coal ash in this manner. (May 26, 2020 ) The 2015 CCR Final rule does regulate beneficial use using 4 criteria. Does the CCR provide a functional benefit? Does the CCR substitute for virgin materials saving natural resources? Does the CCR meet relevant specifications and regulatory standards?. Finally, The EPA requires unencapsulated use of greater than 12,400 tons in non-roadway applications to be evaluated for health risks. It is widely believed the US EPA used the wrong figure in its rule and meant to state 74000 tons.
Unencapsulated Beneficial Use
Unencapsulated uses of coal ash are those where coal ash is used in a loose particulate, sludge or other unbound form. The US EPA considers flowable fills (CLSM), structural fill, mineral filler, road base, and waste stabilzation as unencapsulated uses. In 2018, ACAA reported about 20 percent of CCR (8.1 million tons) are beneficially used in unencapsulated uses. The largest unencapsulated use is CCR used in “structural fills/embankments” (4.6 million tons). In developing a framework to evaluate the potential risks associated with unencapsulated uses of industrial non-hazardous secondary materials (secondary materials) including CCR, the Agency determined that the principles outlined in the 2013 Methodology for Evaluating Encapsulated Beneficial Uses of Coal Combustion Residuals are also applicable and relevant to unencapsulated uses. Therefore, EPA combined the discussion of encapsulated and unencapsulated uses into a single document and renamed it the Methodology for Evaluating Beneficial Uses of Industrial Non-Hazardous Secondary Materials (BU Methodology) to reflect the broader scope. EPA’s BU Methodology may be used to evaluate both encapsulated and unencapsulated uses of a wide range of secondary materials, including CCR.
See this recent risk assessment for flowable fills ( CLSM). This was prepared by Gradient Corp for American Coal Ash Association . Flowable fills are considered unencapsulated use by the US EPA.
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CAER- Center for Applied Energy Research at University of Kentucky in Lexington, KY USA
Coal Ash Management and Remediation: see Charah solutions, Recon Services, Boral Resources, SEFA, SCB International, Trans-Ash, Geocycle, RPM Solutions
Energy and Environmental Research Center (EERC) : University of North Dakota
Environmental Protection Agency (EPA)
Environmental Remediation : of hazardous heavy metals
EUCI- conference in 2019 on CCR
Illinois Pollution Control Board and CCR Disposal
UNC Charlotte. Research into leachability of fly ash regarding its safe disposal.
WOCA 2017: Geosyntec Consultants presented a paper on how bacteria present in ash disposal sites affect the solubility of metals