METHOD FOR SEPARATING CONTAMINANTS FROM WASTEWATER BY AIR FLOTATION COMBINED WITH CHEMICAL INJECTION

摘要

PURPOSE: A method for separating contaminants such as suspended solid and dissolved solid from wastewater by an air flotation process that is combined with chemical injection is provided, which is more economical in comparison with conventional flotation processes such as dissolved air flotation and vacuum flotation because it does not require complex facilities to dissolve compressed air into a wastewater to be treated. CONSTITUTION: The method includes the steps of (i) injection of 30-40% Fe2Cl3 solution(or Al2(SO4)3 solution) into wastewater in an amount of 2 to 20ml/L· wastewater, followed by complete mixing within a period of up to 20 seconds; (ii) injection of a solution dissolved with a polymer at a mixing ratio of 2 to 4g/L·distilled water into wastewater in an amount of 5 to 30ml/L·wastewater, followed by complete mixing within a period of up to 20 seconds.