Fate of Coal: Dumped or Reused?

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Coal: life source of electricity 

The modern lives of many today are built on the consumption of shiny black rocks we like to call coal. Today, coal is the world’s most abundant source of electricity, accounting for 36% of global electricity and 26% of the world’s energy, more than all other non-fossil fuel sources combined. In 2022, the world consumed 8.42 billion tons of coal, and the United States was the third largest consumer of coal after China and India. A byproduct of coal is a significant amount of waste. Coal ash, liquid waste, and waste coal. Liquid waste is toxic water that contains toxins like mercury, arsenic, beryllium, cadmium, nickel, and selenium. 

Coal Ash and health risks 

Coal ash or coal combustion residuals (CCRs) are solid wastes from coal combustion in power plants. In the United States, coal plants produce 140 million tons of coal ash annually. Coal ash has higher concentrations of toxic elements, such as arsenic, radium, mercury, and selenium, naturally present in coal. Coal ash and other waste have been disposed of in landfills, structural fills, and water bodies for decades. This led to toxic elements seeking into the groundwater, soil, and water bodies, contaminating drinking water, agricultural produce, fish, and the air. To place the risks in context, a person has a 1 in 50 chance of getting cancer by drinking arsenic-contaminated water. 

The impact of coal ash spills and exposure to human health is well known. Incidents like the ones in Eden, North Carolina, and Kingston, TVA, are some of the most explicit, drawing attention to the gaps in regulating coal ash disposal, storage, and use. However, another growing concern is the environmental burden of using coal ash and the waste it produces, which has ignited research to find ways to reuse coal ash rather than dump it in landfills. 

Regulation and Reuse of Coal Ash 

In 2015, Coal Ash was categorized as solid waste under Category D of the RCRA. While this may call for legitimate concerns over the omission of the regulatory bodies to categorize coal waste as “hazardous” under Subtitle C, this move is allowed to capitalize on the recycling of coal ash for beneficial purposes under the CCR Final Rule in 2015. CCR reuse requires that the reuse provide a functional benefit, substitute a virgin natural resource, and meet the specific product requirements and standards. Around 38% of coal ash is recycled in agricultural and engineering applications. Reuse serves benefits as it reduces the use of new natural resources, such as mining. When coal ash reuse reaches an economic level, it can also provide a cheaper alternative to consumers. 

Beneficial Reuse of CCR

Coal Ash is reused in a solid form, i.e., when it is bound with other components to form “encapsulated CCR,” or in its unencapsulated form, i.e., loose and unbound, often in a sludge form. In an encapsulated form, CCR is used in concrete, wallboard, bricks, roofing material, and flue gas desulfurization (FGD) gypsum, which is used in gypsum panel products. In its capacity, the EPA has provided a methodology to compare the risks of using the potentially radioactive CCR with similar products without CCR (e.g., regular concrete v fly ash concrete). Encapsulated CCR is said to be the safest form of reuse. 

Unencapsulated Beneficial Use

To share an example, based on the analytical framework and the standard methodology set by the EPA, the beneficial use of unencapsulated FGD gypsum as a replacement for mined gypsum in agriculture has been evaluated. The study shows that the radionuclide activity and dust levels in FGD gypsum are comparable to those in natural gypsum, which addresses radiation and inhalation concerns. The study highlighted the risk of accumulation and release of selenium in surface water and small water bodies. They recommended restricting application rates to 1 ton per acre as a mitigation strategy, posing minimum dangers to human health and the environment. 

Risks of Unencapsulated “Beneficial Use”

Reusing coal serves multiple benefits and is a testament to the innovative potential to solve the waste problem. Studies have found that coal ash in its main forms can contain radioactive levels up to 5 times higher than normal soil and up to 10 times higher than the original coal. The issues that come with the potential health impact are a continued concern. To those who disagree with the environmental problems of coal ash, the economic burden of safe disposal, which has a proven negative effect on human health, is an unavoidable concern. Coal plant owners often find using unencapsulated coal ash as legally permitted structural fills in low-lying quarries, roadbeds, and construction projects financially beneficial and cost-effective.

Why is this a problem? 

To understand this, we must look at the EPA’s disposal requirements for CCR. One of the requirements for safe disposal is storage in landfills or surface impoundments with protective liners to prevent the toxins from leaching into groundwater. It also requires these ponds to be covered and the waste moved to safe locations away from community spaces and high seismic activity. Now, looking at structural fills, it is evident that CCR provides a stable base for construction and can preserve the use of other natural resources. However, no federal or national standard regulates the appropriate quantity of CCR that can be used when the amount is below 12,400 tons. States may have specific requirements. 

In practice, these structural fills are often used in large quantities in low-lying areas, wetlands, sand and gravel quarries, and shallow groundwater areas. These ash-fill projects pose the same danger as unlined landfills because there is no use for impermeable liners, required separation from groundwater, or mandated groundwater monitoring. Therefore, they pose health risks that come from unlined landfills. They also create fugitive dust, which poses health risks. Using CCR in road construction without impermeable covers such as concrete and asphalt fails to prevent the leaching of toxic elements into underlying groundwater or surface water. 

How do we know there is a problem?

Another issue is that no national monitoring standards for CCR are under the threshold amount. Recordkeeping is only possible when there is a state-mandated monitoring and publication requirement. How are people or experts supposed to understand the possibility of a severe health disaster in the shadows if they do not know the risk? 

Proven radiation exposure from structural fills

As of 2023, 180 million tons of coal ash have been used for fill since 1980. The ACAA has also reported that the use of coal ash as a structural fill rose by 40% from 2020 to 2021. Despite what some might call a conservative evaluation of the risks of structural fills, the EPA has found that arsenic in coal ash has a cancer potency 35 times higher than previously acknowledged. Structural fills containing Coal Combustion Residuals (CCRs) pose significant health risks primarily due to groundwater contamination, soil exposure, and radiation. Additionally, gamma radiation and radon gas emissions from CCRs present cancer risks, especially if land disturbances bring CCR material into contact with surface soils. These risks are exacerbated by the likelihood that engineering controls, like soil caps, may degrade or be disrupted over time, allowing contaminants to enter residential areas as land use changes, thus increasing exposure pathways. These are concerns that need to be addressed. 

Sustainable development cannot demand a trade-off between preserving our planet and endangering human lives. We cannot justify recycling toxic materials when it risks poisoning groundwater, releasing harmful radiation, and exposing communities to cancer. The first step would be to acknowledge the risks and devote resources to study how these effects can be eliminated to improve the reuse of CCR. True progress safeguards both our natural resources and the health of those who depend on them.

References 

Coal’s Importance to the World. Read more here. 

EPA Response to Kingston TVA Coal Ash Spill. Read more here. 

Coal Ash Primer. Read more here. 

Coal Ash: Hazardous to Human Health. Read more here.

Environmental groups want stronger rules for use of coal ash fill after EPA reveals new risks. Read more here. 

Draft Risk Assessment of Coal Combustion Residuals Legacy Impoundments and CCR Management Units. 2023. Prepared By: United States Environmental Protection Agency Office of Land and Emergency Management Office of Resource Conservation and Recovery. Read more here. 

EPA: Radiation from Coal Ash Poses Cancer Risk. Read more here.

Hazardous and Solid Waste Management System; Disposal of Coal Combustion Residuals From Electric Utilities. Read more here.