[Algal-flocculation removal by modified sediment of Taihu Lake in wind action]

Removal effects of cyanobcateria algal cells in chitosan-mediated in-situ-sediment in the sediment resuspension was studied in the laboratory. The research simulated the sediment suspension through quantitative simulated the middle-grade wave of lake Taihu, which usually experienced, by using the Y-type sediment resuspended generator. The results showed that the blue-green algal's removal effect is 93.55% and 99.19% as the dosage adding of chitosan and sediment were (0.100 + 0.200) g x L(-1) and (0.150 + 0.200) g x L(-1), respectively. The removal rate of turbidity of the water body reached 78.60% after still 30 min, in which the chitosan adding dosage was 0.150 g x L(-1); the removal rate of turbidity achieved 93.88% after 8 h of water body still. Furthermore, adding the chitosan could decrease the PO4(3-) -P concentration of water body in a short term. Preliminary results showed that the chitosan which adding dosage was 0.15 g x L(-1) could effectively remove the cyanobacteria cells in middle-grade wave situation; and also indicates using the chitosan-mediated sediment to flocculate the algal bloom of the Taihu Lake has a better application prospect. Contrast study shows that the quantitative simulation method of hydrodynamic intensity and the height of water has the obvious advantage to determine the dosage of chitosan in algal-flocculation removal.