The Science of Sustainability

Coal Ash Conundrum

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What happens to the river ecosystem when tons of coal ash gets mixed into the layer of sediment on the river bottom? Photo credit: Pete Harrison, Waterkeeper Alliance.

QUEST North Carolina’s Daniel Lane contributed to this article.

On a Sunday in February in Eden, North Carolina, a sinkhole formed in the middle of a pond of coal ash slurry next to the retired Dan River Steam Station. A stormwater pipe underneath the ash pond cracked and was sucking in ash and shuttling it to the nearby river. Duke Energy, owner of the facility, sent emergency crews to the site, but it was a complicated fix. By the time they got it securely sealed on Thursday, the 48-inch pipe had belched more than 39,000 tons of coal ash into the Dan.

The Dan, a major tributary of one of the largest and least disturbed ecosystems on the East Coast, ran gray. From Danville, Virginia, whose 42,000 residents draw their water from the river, to Kerr Lake, home to seven recreation areas with 800 miles of trails, a gray ribbon of coal ash was visible along 70 miles of prime sport-fishing territory.

Coal ash can have 24 times the concentration of selenium compared to native soil. Click to enlarge. Courtesy: EPA

What Is Coal Ash?
Coal ash is a byproduct of burning coal to make electricity. For every nine million tons of coal burned in the U.S., approximately one ton of coal ash is produced. Coal ash is a highly concentrated source of the mineral content that is left after the carbon is burned. It is similar to soil in terms of grain size and texture but contains high concentrations of toxic elements like selenium and arsenic. Coal ash is typically stored wet behind earthen dams adjacent to the power plant. The security of these impoundments is currently under review. The EPA is assessing the hazard potential of the 676 impoundments around the country. As of March 2014, 52 surface impoundments were given a “high” hazard potential rating by the EPA, meaning a failure of the impoundment is “probable, one or more expected.”

Why This Matters
Water tests at the Danville water treatment plant showed a spike in arsenic in the first days of the contamination, but arsenic levels returned to normal a week later. The ash, however, was not gone. It was just gone from view, merged with the most fertile zone in a river — the nutrient-rich and life-giving layer of sediment.

Most species of aquatic insects live in the sediment, collecting, filtering, and grazing upon minute particles of food. Nothing goes to waste down there, not even the arsenic and selenium from coal ash. Heavy metals get lodged into the tissues of any insect that eats them. When minnows eat the insects, they consume the toxins. Larger fish get toxins from every minnow they eat. As you climb higher in the food chain, the amount of arsenic or selenium you find multiplies progressively. This process is called biomagnification and it has impacts on a food web from bottom to top.

Dr. Dennis Lemly, research fish biologist and professor of biology at Wake Forest University, calls selenium an “invisible” toxin because it doesn’t directly harm the fish that eats it. “Instead, it migrates to the ovaries and enters growing embryos, causing defects in major organs and physical deformities in the head, spine, mouth, and fins (see effects of selenium poisoning in North Carolina here). A lot of them die shortly after birth,” Lemly said. “So over a period of two or three years, the older fish die off and there’s no young ones to replace them and repopulate. They just die off.”

Location of coal ash contamination sites as of Feb, 2014. Red denotes a coal ash contaminated site. Green denotes a coal ash spill. Black denotes both a contaminated site and a spill. Source: EPA Coal Ash Damage Cases. Map courtesy Arc-GIS

Location of coal ash contamination sites as of Feb, 2014. Red denotes a coal ash contaminated site. Green denotes a coal ash spill. Black denotes both a contaminated site and a spill. Click to enlarge. Source: EPA Coal Ash Damage Cases. Map courtesy Arc-GIS

The Future of Coal Ash Disposal
While the long-term effects of the Dan River coal ash spill won't be known for a while, the short-term effects may be influencing regulation. In 2008, the catastrophic 1.1 billion gallon spill in Kingston, Tennessee, galvanized public debate about coal ash storage. In 2010, the EPA proposed the nation’s first-ever rules to ensure the safe disposal of coal ash. According to the EPA, “these rules would ensure stronger oversight of the structural integrity of impoundments in order to prevent future accidents.”

Dr. Lemly is in favor of more regulation, “I have been on record many times recommending a complete banning of the surface disposal in impoundments. I continue to do that. I’m hopeful that the EPA ruling on coal ash that is supposed to come out in December will provide a complete ban on surface impoundment disposal.” The EPA is expected to finalize their rules for coal ash on December 19.

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Category: Biology, Blog, Environment, Geology, Water

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Lucy Laffitte

About the Author ()

Lucy B. Laffitte, PhD has been a science communicator and environmental educator for over thirty years. She has produced in-class and on-line instructional design, curriculum development, and certificate programs to a variety of conservation organizations, including the Oregon Museum of Natural History, Tall Timbers Research Station, North Carolina Museum of Natural Science, Salt River Project, New England Wildflower Society, Rachel Carson Institute, and Nicholas School of the Environment. She has published in print and on air—writing a nature column for The Cape Codder and was the founding radio producer for the environmental program the Allegheny Front. She has a bachelor’s degree in natural science, from the University of Oregon, a Master’s in adult education and graphic design and a PhD in environmental resources from North Carolina State University. She has been science education consultant for UNCTV working on QUEST and NC Science Now since April 2013.
  • Robert Merrick

    Dr. Laffitte has posted an excellent article, and I sinceerly hope she continues to publish additional information on this subject – - regularly – - very insightful! The information will enable citizens to make informed decisions on how we can hold energy companies and politicians accountable to eliminate the coal ash dilemma.

    It's time to tax coal ash so coal burners are motivated to recycle and use technology to eliminate coal ash entirely. Let's say a tax of $10 per ton of coal ash is levied on every coal-fired plant in the US. With 140,000,000 tons of coal ash per year being produced, about 90,000,000 million tons is being buried and stored for later disposal (fill), while the rest (about 45,000,000 tons) is being used in concrete and other products. Do the math. 90 million tons per year generates 900 million dollars of tax that can be used to clean up the mess that's being made by the current coal ash disposal. Duh, why can't energy companies, the EPA and politicians figure this out?

    Here's the plan. All coal ash produced by US coal-burning energy plants will be taxed at a rate of $10 per ton. At the rate of 140,000,000 tons per year generated in the US, the coal ash tax potentially generates $1.4 billion per year that would be held in an environment cleanup trust fund, controlled by publicly elected representatives living in communities near coal ash disposal sites, much like your mayors and sheriffs. If the coal ash disposal site is located within a flood plain or near a waterway, the coal tax would be doubled to a rate of $20 per ton.

    Motivators to escape the coal ash tax are simple. First, the coal ash tax is waived on ash that is recycled for building materials, which currently averages 40% at typical US coal-fired plants. Of the 140,000,000 tons currently produced each year in the US, about 56,000,000 tons are reused in building materials. That brings the
    Coal Ash Tax Trust Fund (let's call it the CATT Fund) down to an annual potential of $840,000,000 for the coal ash that's being disposed in landfills. But if a landfill or holding area (e.g., pond) is on a flood plain or within 500 yards of a waterway, an additional tax of $10 per ton is levied on ash disposed in those sites. For round
    numbers, let's assume the CATT Fund will collect $1 billion in taxes annually for the mix of disposal sites.

    At a $1 billion in taxes, one would think energy companies will be motivated to eliminate coal ash altogether. Their second option is to apply a technology that was developed, tested and is being implemented by the US Department of Defense. A very-high-temperature process known as plasma-arc waste destruction is currently being installed on the next-generation of US Navy aircraft carriers. These plasma-arc systems can be optimized for a variety of waste streams. For coal ash, a plasma-arc system can be packaged to eliminate 98% of the coal ash currently being buried in landfills. That's roughly 82,000,000 tons of coal ash that can be kept out of your waterways and nearby landfills.

    So what do you do with the remaining 2,000,000 tons that's left each year? Using plasma technology, it becomes a glassy like material that is an inert binder of minerals that traps traces of formerly toxic residuals, which can also be used for building materials. There's even a young, enterprising genius in Baltimore who wants to collect it to make synthetic granite countertops. But there are dozens of other potential and high-value uses, particularly if you are a ceramics engineer who can add certain ingredients to the molten glass as it pours out of the coal plant's plasma system.

    The third motivator for energy companies using coal-fired plants is research and development derived from a 10% portion of the CATT Fund. Qualified companies would be able to propose R&D projects that achieve greater efficiencies in coal ash
    elimination or improve processes, such as systems that extract synthetic gas from
    the coal ash that can drive a turbine generator – - and produce more electricity! If a company's coal ash elimination R&D project is successfully demonstrated and implemented, that company would be reimbursed from the CATT R&D Fund.

    In summary, neither energy companies nor their electricity customers would have to pay a cent of coal ash tax if all of the coal ash is reused for building materials, eliminated with technology such as plasma systems, or converted to energy with yet-discovered processes via CATT Fund.

    So how do we as citizens put the Coal Ash Tax on our November ballots? It's probably too late in most towns. But if you're serious about a Coal Ash Tax that would inspire energy companies to keep your water and land clean, there's a way to make it happen. Vote for the candidates who pledge to support the coal ash tax – - but make them draft the legislation before the elections so you can read it and you know they're serious about starting the effort on their first day in office. You must establish the carrott and stick first to hold politicians and energy companies accountable to the people they serve and service.

    Beware of the political candidate who tells you a coal ash tax is not the solution; this means they don't have a plan to stop coal ash from being buried in your backyards, and it means they don't have a clue about harnessing existing technology to eliminate coal ash. Your vote for the right candidate could begin to eliminate all the coal ash in your community during that candidate's term. In a few years, coal ash could be something we had to live with before American voters got involved.

  • Johnny Bennett

    Coal ash should be use to make brick with. for Insolation .in homes