Study Of The Efficacy On Algae Removal Using Fluidized Carriers

Currently, various algae removal methods have some shortcomings, if used alone, it is difficult to achieve the desired effect of algae removal. In this study, the process of stirring fluidized carriers pretreatment was used to remove algae in Taihu Lake Basin water in a river. The main contents included:(1) the selection of fluidized carriers,(2) determining the experimental parameters,(3) the selection of modified methods,(4) the experiments of algae removal using powdered modified granular steel slag,(5) the experiments of high temperature modification steel slag pretreatment associated with coagulation processes to remove algae. Four kinds of fluidized carriers (filter sand, zeolite, limestone and granular steel slag) under mechanical stirring have an effect to remove algae in source water. Limestone has the best overall effect of algae removal, zeolite and granular steel slag followed by and filtration has the worst. Granular steel slag due to hard, little effect on water turbidity and good effect of algae removal, may be considered to apply to remove algae in the water purification plant after pretreatment. The factors of algae removal using modification steel slag in descending order was modified method, granular steel slag size, stirring time and stirring intensity. Granular steel slag after high temperature modification had the best effect of algae removal. The removal efficiency of chlorophyll a increased with the decreasing of granular steel slag size and increased with the increasing of stirring intensity and stirring time. Granular steel slag after one of the two modified method of high temperature modification and chitosan-coated modification had a good effect of removing algal cells, cyanobacteria, green algae and diatoms in water and could effectively reduce algae photosynthetic activity to inhibit the growth of algae. Modified granular steel slag under low mechanical stirring intensity (lOOr/min) had an effect on the removal of mixed algae in water, its mechanism based mainly adsorption. High temperature modification of granular steel slag under high mechanical stirring intensity (400r/min) had a good effect on the removal of cyanobacteria, green algae and diatoms in water. The removal of mixed algae increased from28.00%to more than73.00%, the increase was mainly due to the granular steel slag under mechanical stirring damaging the algae cell. The high temperature modification granular steel slag pretreatment associated with coagulation processes had a good effect on mixed algae removal and the average chlorophyll a removal rate was over91.4%, much higher than that of the high temperature modification granular steel slag pretreatment and coagulation process. The two processes had synergistic effect on removing algae.