Numerical and experimental study of floc characteristics induced by fully baffled mixing tank agitated with retreat curved impeller

This study examines the impact of mixing methods in enhancing the coagulation-flocculation process. Two types of coagulants: Aluminum Sulfate Hydrate [Al2(SO4)3.16H2O] and Magnesium Chloride [MgCl2] were used. The polymer polyacrylamide (C3H5n) was utilized as a flocculent aid. A fully baffled mixing tank agitated with retreat curve impellers rotates in the range of as an increment step and a mixing time of was used in the present study. The present investigation includes two methodologies: the first is based on numerical solutions using MIXSIM 2.0 and ANSYS Fluent, while the second is based on experimental work. The Kaolin particles were utilized to represent the suspension collides in natural raw water. The image analysis technique was used to determine the surface area of producing flocs. The results established that the most appropriate impeller rotational speed for the flocculation process is in the range of and for alum coagulants. The maximum surface area of the floc was found to be produced at with of mixing time and the maximum final floc surface area was at and of mixing time. For magnesium chloride coagulant the max surface area of floc was produced at and of mixing time, the best impeller rotation speed was produced the final surface area of floc which is 0.783 after of the mixing tank. These types of floc are appropriate for the sedimentation process to be followed by the normal procedure of drinking water treatment.