The Optimum Conditions For Fluoride Removal From Drinking Water Using Nalgonda Method (Flocculation And Sedimentation)

) ( - . ) (. ) 88 %( ) 3( / ) 88 %( ) 01 ( / . )pH( ) 88 %( ) 4( ) 9( )pH( 7( ) 77 %( ) 83 %( ( . . ) 0 ( 8 (. ) 3 ( ( . ) 0 ( .The Optimum Conditions For Fluoride Removal From DrinkingWater Using Nalgonda Method (Flocculation And Sedimentation)Dr. Kossay K. Al-Ahmady Zainab A. ZnadUniversity of Mosul College of Technology, KirkukCollege of Engineering, Environmental Eng. Department Environment and Pollution Eng. Department.AbstractThe Nalgonda method is one of the effective methods for fluoride removal, especiallywith low and medium initial fluoride concentrations. In this research, the idealconditions were found through studying the factors that affect the fluoride removalefficiency (initial fluoride concentration, pH, alum dose, mixing time for flocculation andcoagulation processes, and the sedimentation time). The research results proved thatinitial fluoride concentration does not significantly effect the efficiency. As the removalefficiency amounted to (88%) for the initial fluoride concentration of (3) mg/L. Whilethe removal efficiency was equal to (86%) for an the initial fluoride concentration of (10)mg/L. pH value was proved to be effective, as the removal efficiency was equal to (85%)when the (pH) value is equal to (7), while the removal decreased to (72%) and (63%)when the (pH) values were equal to (4) and (9) respectively. Alum dose, time of mixing,and the time of sedimentation were also affecting on the removal efficiency. Bestremoval efficiency obtained at the times of mixing and flocculating equal to (1 min) and(5 min) respectively. Also it was found that its possible to get the same removalefficiency when increasing the period of rapid mixing to (3 min) and then directly moveto the sedimentation process. Finally, the ideal sedimentation time has been set, bestremoval efficiency has been achieved a sedimentation time equal to (1 hour) and at thedifferent measurement conditions.Keywords: Flouride removal, Drinking water, Nalgonda method, Flocculation, Sedimentation