压力作用后太湖蓝藻沉淀性能及其去除研究

Sedimentation and Removal of Cyanobacteria in Taihu Lake under External Pressure

为了强化太湖蓝藻的混凝沉淀去除效果，采用外加压力破坏藻细胞内的气囊，使藻类失去浮力，再经混凝沉淀去除。试验测定了太湖蓝藻在短时外压作用后的上浮（沉淀）情况，结果表明：当作用压力≤0.1MPa时，藻类上浮；经0.2～0.3MPa压力作用后，大部分藻类悬浮于水中，少量藻类上浮，少量藻类下沉；经0.4～0.6MPa压力作用后，藻类下沉。场发射透射电镜扫描发现，经外加压力作用后藻细胞内的气囊消失，藻细胞壁完整，藻液没有外泄。小试结果表明，经0.6MPa压力作用后，再加入16mg／L的聚合氯化铝进行混凝沉淀，对藻类的去除率可达到95％以上，出水浊度〈2.5NTU，优于NaCIO预氧化／混凝沉淀工艺的除藻效果。压力预处理可以作为蓝藻去除技术的一个发展方向。

In order to improve the removal of cyanobacteria in Taihu Lake by the coagulation and sedimentation process, external pressure was applied to collapse the gas vesicles in algal cells, reduce algae buoyancy, and remove algae by coagulation and sedimentation. The floating and sedimentation velocities of the Taihu Lake cyanobacteria were measured after a short-time external pressure was applied. The algae floated up when the pressure was ≤0.1 MPa. Most of the algae were suspended in water while only a small amount floated up, and some algae sank down when the pressure was between 0.2 and 0.3 MPa, much more when the pressure was between 0.4 and 0.6 MPa. When algae were subjected to external pressure, the gas vesicles in algal cells disappeared. The algal cell wall was intact, and the algae fluid was not leaked out. After applying 0.6 MPa of pressure and adding 16 mg/L of polyaluminum chloride, the removal rate of algae by coagulation and sedimentation was more than 95%, and the effluent turbidity was less than 2.5 NTU, which was superior to the combined treatment of NaCIO pre-oxidation, coagulation and sedimentation. Pressure pretreatment could become a technology to remove cyanobacteria.