Reducing of leachable fluoride in coagulation sludge arise from flue gas desulfurization unit of a coal fired power plant

Coal fired power plants are, currently, the most-widely used technic for electricity production, however they cause various environmental pollution. There are a number of cleaning techniques to provide pollution from coal burning and one of them is to use wet system flue gas desulfurization units. Wastewater from wet FGD units should be chemically treated before discharge. The coagulation sludge from chemical treatment is finally disposed in special landfill deponies.In the existing power plant, concentration of leachable fluoride in coagulation sludge remains within ?hazardous waste? limits according to the Hazardous Waste Regulations in Turkey and the sludge is disposed to the landfill area. This study aims to reduce the leachable fluoride concentration from coagulation sludge of the plant. For this purpose, different coagulants and pH regulators were used for chemical treatment of wastewater and consequently leachable fluoride concentrations were measured from coagulation sludges in order to observe the effect of chemical treatment applied.