Power Plant Dewaters Fly Ash Pond to Comply with EPA Regulations

BACKGROUND
A coal fired power plant in the Midwest was capping two 10 acre ash ponds to comply with recent EPA regulations. They needed to remove the water from the ponds and dry the soil so that the remaining ash could be excavated and the ponds could be capped. Because the ash was particularly dense, wellpoint dewatering would not be effective.

OUTCOME
Rain for Rent recommended a French drain around the perimeter to dewater the soil. A combination of 4 and 6-inch pumps removed the water from the ponds prior to treatment and discharging. Weir tanks, sand media filters and bag filters helped meet discharge limits after the water was treated with chitosan flocculant.

HIGHLIGHTS
The original scope was to dewater the pond in two weeks, but the pumps were able to remove the water in just five days.
Rain for Rent’s Engineering team looked at soil samples to determine permeability of the soil and fly ash. They determined that a typical wellpoint system would not be effective and recommended a French drain system.

CUSTOMER FEEDBACK
The customer was very impressed by Rain for Rent’s ability to provide a solution to help them comply with EPA regulations. The system worked better than expected and the power plant is utilizing Rain for Rent’s equipment and expertise at other plants with ponds that need to be closed or capped.