In a perfect world the planet’s energy source would be generated from an infinite or renewable source not a finite source, and its by-product would have beneficial reuses rather than have harmful effects to human or environmental health. However, the world is not perfect, nor is nuclear or coal power energy. Though much research is going into other renewable sources of energy, neither coal nor nuclear plant technologies will likely go away any time soon given the vast infrastructure already in place for these technologies and the capital investment involved.
Thus, environmental policy and priorities should rate coal and nuclear power with respect to the damages each causes to the environment, to human health, and to the future security of ones surroundings. The by-product of an energy source and the threats it poses to ones security is the linchpin in rating the difference between coal and nuclear energy plants.
The recent spill of coal ash from the Tennessee Valley Authority’s (TVA) coal fired plant that impacted 300 acres and the Tennessee River on December 22nd is a case in point that has many questioning the credibility and application of coal fired plants in the United States. Green Peace recently cited that coal ash is a hazardous and toxic waste and sensationalized and distorted the facts about this spill. Let us get the facts straight about coal ash.
Although coal ash has metals and organics that at specific levels could be classified as hazardous, coal ash however, is not classified as a hazardous or toxic waste stream. The reason for this is that coal ash, commonly referred to as fly ash or bottom ash, is predominately made up of calcium, which has a binding capacity. When mixed with water, the metals that leach from fly ash are nearly insignificant because the calcium locks or binds the metals in place in large part preventing the metals from being free floating or suspended particles that could otherwise be harmful to aquatic and human health.
Leachate tests are performed on waste streams to determine how harmful or hazardous a waste stream can be. An EPA test called Toxicity Characteristic Leaching Procedure (TCLP) is a test used to characterize waste streams as hazardous or non-hazardous and determines the potential of a waste stream to leach into the ground water. Coal ash, because of its binding capacity, is clearly not a hazardous or toxic waste because the metals do not leach into the water table at levels that pose a threat to human and environmental health.
Facts about Coal Ash
o Coal ash is not a hazardous or toxic waste.
o Coal ash is partly comprised of lime and when mixed with water acts as a binding material and is used in making concrete.
o Coal ash is usually referred to as “fly ash.”
o Two types of fly ash exist: Class F and Class C, usually referred to as fly ash and bottom ash respectively.
o Bottom ash is used as aggregate in road construction and building foundations.
o Fly ash is used in supplementing the creation of concrete and as filler in asphalt.
Coal Ash and Drinking Water
Bizhan Sheikholeslami, an environmental engineer who specializes in fly ash regulations with the Wisconsin Department of Natural Resources, said that the quality of the coal and the type of coal-fired boiler used in the process will determine the quality and waste characterization of the fly ash. In general, however, he professes that after water leachate tests are performed on bottom ash only trace levels of barium, boron, iron, and magnesium were detected from two local boilers and were well within drinking water standards.
Fly ash has more metals than bottom ash however. Bizhan’s report on fly ash revealed high levels of metals but significantly lower levels of metals after the leachate test was performed. Levels of aluminum, barium, PBN Crucible, and molybdenum were detected that exceeded drinking water standards in one particular case he posed. Therefore, water treatment plants must be cognizant of these threats in Tennessee and should take extra care in making sure these metals are removed from drinking source.
Coal Ash and the Environment
Storing fly ash next to a sensitive natural environment, such as a river, is not a sustainable environmental choice and the risks associated with such should be measured. The aftermath of a coal ash spill and the impacts that large quantity spills have on the environment have some implications to the benthos community or the bottom of the water body where invertebrates and aquatic food sources are for smaller fish such as minnows. Minnows are food sources to larger fish and some concern may develop over time regarding the increase of metals in the food chain.