Shear schedule determination method using image analysis of flocculation processes

摘要

This study proposes a batch test procedure for the determination of shear schedules in conventional flocculation processes consisting of three successive flocculation basins. The determination is based on variations in the average floc size, indicating floc growth or breakage. The trends in the floc sizes with varying shear schedules are in good agreement with those of the residual turbidity. It is found that formation of large flocs is important for maintaining their large size in subsequent stages, given an appropriate selection of the shear strength. This suggests that shear strength should be selected on the basis of floc size. The suggested testing procedure offers a range of effective shear schedules, and the optimum shear schedule can be selected based on the requirements of subsequent processes or restrictions of the operational conditions.