Containment pits and basins for coal ash aren’t the easiest kind of impoundment to line. While other types of retention ponds are designed specifically for evaporation or short-term storage only, these containment pits must hold large volumes of waste for long periods without risking collapse or seepage. Yet, the very design features necessary to keep them easy to dredge and to added recycling options for the water also make it tricky to line these impoundments. Make sure you’re meeting the latest EPA and state requirements on lining coal ash pits and ponds by choosing a liner product that can handle all of these challenges and more.
Steep Sides for Direct Burial
Direct burial pits are popular in areas where they’re allowed by state law because these structures allow for on-site disposal of coal ash. There are no transportation costs, discharge permits, or landfill fees associated with this method. However, there is the need to excavate a very deep pit with relatively steep sides without causing the liner to slip off the surface. Lining is essential to prevent erosion or seepage in these pits, but it’s also physically challenging to accomplish in a deep and steeply sided pit. Anchoring the material to the sides can end up puncturing the material and causing leaks instead. Before assuming a direct burial pit is achievable because you have access to an affordable and reliable liner material, make sure to factor in the costs and risks inherent to the design.
Large Scale
The sheer scale of each impoundment cell or pond for coal ash residue storage makes them difficult to fully line. Even with custom manufacturing, to create seamless panels that stretch hundreds of feet in each direction, it’s almost impossible to completely avoid seam sealing with these installations. Each foot of seam sealed represents another risk for a leak to form. Every extra square foot of liner also creates new opportunities for leaks to form. Installation is a challenge for even the smallest pond but making an impoundment to hold one billion gallons of slurry or more can feel downright impossible. Extra flexible and reinforced liner materials go a long way in making such a large-scale installation much easier to achieve.
Abrasive Materials
The materials that accumulate on the bottom of the coal ash slurry pit are particularly abrasive. Ash may seem light or even fluffy in texture in small amounts, but once mixed with water and compacted into a sludge, the material is more like a sharp-grained sand. This abrasiveness has a constant wearing effect on the liner, which is further compounded by the need to constantly dredge the pond to maintain its volume.
Don’t settle for a lesser liner when working to build coal ash containment features that will be used for years. BTL Liners has durable, quality products that can withstand the most challenging installations. Let us help you choose the right product for your coal ash impoundments and containment areas.
