CONTINUOUS REMOVAL OF HEAVY-METALS FROM FGD WASTE-WATER IN A FLUIDIZED-BED WITHOUT SLUDGE GENERATION

A patent pending fluid-bed process has been developed by Kruger for re moval of dissolved heavy metals by adsorption/coprecipitation. The was te product is a very compact granulate with a very low water content o f 10-20%. Sludge is not produced. The fluid-bed technique was tested a t a coal-fired power station with wastewater from the flue gas desulph urisation (FGD) unit for removal of heavy metals from the wastewater. By dosing only potassium permanganate to the wastewater, the content o f dissolved nickel, cadmium and zinc was reduced by respectively 99%, 92% and 97% at optimum treatment in one fluid-bed reactor. The weight of waste product produced will constitute less than 25% of the waste p roduct produced by the present traditional chemical precipitation. Che mical costs are approximately 0.6 US$/m(3) which are similar for the f luid-bed and present wastewater treatment processes. (C) 1997 IAWQ. Pu blished by Elsevier Science Ltd.