Fly ash is a by-product of burning coal. Coal-burning electricity generating facilities produce significant amounts of fly ash as a result of normal operation. To clear out fly ash from such a plant, a stream of water is typically introduced to collect the fly ash in suspension in forming a flowing slurry which is deposited in a nearby contained area. The water may be decanted or otherwise separated from the slurry and recirculated to remove further fly ash. Over time, a fly ash pond or pit may be formed containing significant amounts of fly ash.
Recent federal regulations require the closure or remediation of coal ash ponds or impoundments. The regulations allow for various closure or remediation options such as capping, consolidating into a new landfill, disposing off-site, converting to wetlands, or any combination of these options. Difficulties are presented in handling and working on fly ash across large surface areas, particularly due to its instability. Dewatering and/or stabilization of the fly ash is often necessary. This instability results not only from the fineness of the fly ash, but also the presence of water and the fly ash being found in large quantities. Dewatering a fly ash pond or pit increases the stability of the fly ash to allow for better handling thereof.