By MELISSA CROCKETT MESKE
When coal is burned to produce energy, the resulting byproduct is ash. Coal ash disposal, especially in ash ponds, continues to be an environmental hot topic. However, one local firm is applying an approach for decommissioning ash ponds that not only protects the environment and addresses concerns, but also aligns with Illinois Environmental Protection Agency and USEPA guidelines.
Headquartered in St. Louis, Geotechnology, Inc. has locations in eight states including one in Fairview Heights. A recent project involved closing four eastern Illinois coal ash ponds, where they provided construction quality assurance and construction management services.
Dr. Anna Saindon of Geotechnology explained that there are two methods for removing coal ash commonly used in the industry. One is the dry method, where dry ash is transported to a landfill similar to household waste. The second is a wet method known as sluicing, where ash and water are mixed, then pumped to ponds. The wet method is used less today, but historic and current ponds must be addressed.
For this project, Saindon said that three of the four ponds were managed through a clean closure process. They were smaller in nature, so all of the coal ash was removed and placed in the fourth, larger pond.
The fourth pond was constructed so that storm water would flow off and not get into the ash. This pond was lined and capped with a geomembrane that would keep rainfall out and prevent leaching. To protect the cap from damage, a three-foot soil cap is placed over the geomembrane and seeded to limit erosion.
Saindon said that in addition to helping carry out the closure and Construction Quality Assur ance plans, Geotechnology provided soil laboratory testing, field sampling and testing, slope stability evaluation, and assessment of soil and clay cover sources.