胞外分泌物对铜绿微囊藻混凝去除的影响

Effect of Extracellular Organic Matter on Microcystis aeruginosa Coagulation Removal

以铜绿微囊藻为对象,研究了胞外分泌物(EOM)对不同类型混凝剂混凝除藻的影响,并初步探究了其影响机理.结果表明,不同类型的混凝剂具有不同混凝特性和混凝除藻效果.EOM对混凝的影响具有利弊双重性,即在混凝初期由于优先结合混凝剂,减小了有效投加量并阻碍电中和,具有一定的负面效应;而在混凝后期,初期与混凝剂结合的EOM具有增强架桥和网捕卷扫作用,起到了提高絮体密实性和改善沉降性能等有利作用.综合而言,当EOM质量浓度处于3～5mg.L-1时,混凝剂的除藻效果最好.因此,合理利用EOM是提高混凝除藻效果、减少药剂投加量的重要因素.研究结果为不同环境条件下除藻剂及其工艺条件的选择提供了重要的参考依据.

Effects of extracellular organic matter（EOM） on algae coagulation removal were investigated with different types of flocculants.Different flocculants varied in their effects on coagulation performance and algae removal efficiencies.EOM could both beneficial and harmful effects on the coagulation.At the beginning of coagulation,EOM unified the flocculant,and subsequently reduced the effective dosage and hindered the charge neutrality of the flocculant.In the later period of coagulation,EOM could strengthen the adsorption bridging and entrapping-sweeping functions,and thus made the floc more close-grained and improved the settling property.Results show that EOM can aid the coagulant to remove algae when combining with flocculants.When the concentration of EOM fell within 3～5 mg ·L-1,the effects of coagulation on algae removal is optimal.In short,the addition of EOM can decrease the flocculant dosage and enhance the efficiency of algae removal when it is used properly.This study provides practical suggestions on the technical modifications of flocculants in blue algae removal.