Evaluation of a droplet spraying/misting system to enhance leachate evaporation and reduce leachate treatment costs: a case study at the three rivers solid waste authority landfill

Three Rivers Solid Waste Authority (TRSWA) operates a MSW landfill outside Jack- son, South Carolina at which leachate is stored in a collection pond then trucked to a local wastewater treatment plant (WWTP) for treatment. This landfill operates a droplet spraying/misting system (referred to as the Lilypad system) to enhance leachate evaporation and ultimately reduce the quantity of leachate in the pond that requires subsequent treatment. Little work investigating the efficacy in using such a system to enhance leachate evaporation has been reported. The overall goal asso-ciated with this study was to quantify the amount of evaporation enhanced by the droplet spraying system and evaluate how the economics of the enhanced leachate evaporation compare to hauling leachate to a WWTP. This was accomplished by per-forming a water balance on the pond, developing a simple model to link leachate evaporation to the droplet spraying system, and performing an economic evaluation of the system. Overall, results from this work indicate the use of a droplet spraying/ misting system to enhance leachate evaporation at on-site storage/collection ponds is effective, resulting in between 2.1 to 2.6 times more evaporation than what would occur naturally. In addition, the economic evaluation of this system indicates that operating the Lilypad system at maximum speed/flow for the greatest number of hours results in saving up to 7% of the total cost when compared to no operation of the Lilypad system.