Treatment of Reservoir Water Derived From the Yellow River by Potassium Permanganate Pre-oxidation/ Dissolved Air Flotation/ GAC-sand Filter Combined Process

Aimed at the raw water quality characterizd by low temperature and low turbidity in winter, high algae and organic matter in summer, the combined process of potassium permanganate pre-oxidation/ dissolved air flotation/ GAC-sand filter was developed to treat high algae water in Queshan reservoir. Test showed that the process could reach a better result when the dosage of potassium permanganate preoxidation was 0.3 mg/ L, the dosage of PAFC was 3 mg/ L (Al³⁺) , the dissolved air pressure was 0.3MPa and the recycle rate was 11%. The averaged removal efficiency of TOC, turbidity, particulate matter, chlorophyll a and blue-green algae by combination process were 46. 68%, 94. 45%, 99. 34%, 66. 64% and 95. 44%, respectively. Odor level decreased with process flow, from raw water level 4 to effluent level 1. 5. GSM treated by flotation unit was under the detection limit, and the removal efficiency of MIB reached 92. 47%. The removal rate of each component of THMFP, including CHCl₃, CHCl₂ Br, CHClBr₂ and CHBr₃, were 42.86%, 24.09%, 30.30% and 37.50%, respectively. The combined process has a good ability to remove regular indices, algae, odor substances and precursors of disinfection byproducts.