In the Oct. 3 article “EPA coal ash proposal would lessen restrictions” I see no direct reference to fly ash, the dominant, beneficial component of coal ash.
Fly ash, among other uses, can serve as a direct substitute/replacement for some of the Portland cement in concrete, gypsum and similar products. Fly ash can be easily extracted from the exhaust stream of coal combustion and is more economical and environmentally friendly to produce than regular Portland cement.
When fly ash is extracted from coal ash, less bottom ash, which is more likely to contain potentially hazardous materials, remains. It can be disposed of in lined pits away from water sources, thus lessening the coal ash disposal problem.
A predecessor to Duke Energy, Carolina Power & Light, decades ago pioneered in the beneficial use of fly ash at its Roxboro plant. CP&L furnished fly ash to a number of wallboard manufacturers near Roxboro for use in gypsum.
This, along with other uses of fly ash— such as, in Sioux City, Iowa, building two huge concrete silos for storing excess fly ash produced in the winter for use during the summer construction season — were reported at the time of the February 2014 Dan River spill.
Yet, coal ash containing fly ash continued to be placed in wet pits. We even imported coal ash from places such as China and India, despite the difficulty of extracting fly ash from wet coal ash.
In view of the value of fly ash and the coal ash disposal problem, it appears prudent to adopt the practice of extracting fly ash from coal ash in the exhaust stream more widely.
Several companies have equipment and systems for doing this.