铜绿微囊藻的混凝特性与影响因素研究

Flocculation characteristics and influential factors of Microcystis aeruginosa

以实验室纯培养的铜绿微囊藻为试验材料,用烧杯试验调查铜绿微囊藻的混凝特性。结果显示聚氯化铝(PAC)混凝铜绿微囊藻的效果较好。PAC对水样中铜绿微囊藻的混凝效果与藻的生长期、藻细胞胞外分泌物、温度、pH等有密切关系:铜绿微囊藻处于稳定期以及中性到弱碱性的pH范围有利于PAC混凝;温度对PAC混凝的影响与生长期有关,24-26℃对稳定期藻类的混凝沉淀最有利,对数期和衰亡期藻类需要较高的混凝温度(28-30℃);各个生长期铜绿微囊藻的胞外分泌物均有助于PAC的混凝沉降。天然水体中这些因素的耦合作用使得混凝工艺单元有效控制藻类变得困难。控制某一个或几个因素可以改善铜绿微囊藻混凝效果,其中以调节进水pH最为方便。

Based on laboratory cultured absolute strains of Microcystis aeruginosa, the flocculation characteristics of this algae by flocculants were investigated. And by the jar test it is found that PAC was the best one and its coagulation effect on Microcystis aeruginosa was controlled by the cell phase, extracellular organic matters, water temperatures and pH values of sample. Cells in stationary phase were well flocculated by PAC, but by the other two not, the pH values varying in range of neutral and alkalinous were good for cell flocculation, and the extracellular organic matters from all phases were beneficial to flocculation. Water temperature played different roles in different phases, 24℃ to 26℃ was good for stationary phase and 28℃ to 30℃ was good for the other two phase. Conjugation of the above factors made Microcystis aeruginosa hard to be removed in routine drinking water treatment processes. Comparison of the factors showed that adjustment of pH was a relative easy way to remove Microcystis aeruginosa for PAC flocculation.