Comparison of Dissolved Air Flotation and Conventional Sedimentation in Turbidity Removal Source Water Using Poly Aluminum Chloride as Coagulant

surface run off from different levels of a land carry many types of impurities and so it should be purified before any consumption. To separate these materials three processes can be used: sedimentation, filtration and flotation. The objective of this study is comparing the flotation and conventional systems in removed turbidity. This is an experimental - intervention in a pilot scale study that compare the turbidity, alkalinity, temperature, pH and TSS in conventional sedimentation system with those of dissolved air flotation. Method in this study, poly aluminum chloride used as a coagulants and kaolin was used to produce turbidity. The results showed that was turbidity removal efficiency of dissolved air flotation system in turbidities NTU20, NTU50-30 and NTU110-90,were respectively 14.7, 11.1 and 10.9 percent higher than those of the conventional deposition system, determined of the level of (p<0.01). According to these results to remove turbidity by dissolved air flotation system then is more effectively to common sedimentation. System Using this system for turbidity removal in a water treatment plant with a relative turbidity from stormy areas that often receives turbid water, is recommended.