Effect of Extracellular Organic Matter on Microcystis aeruginosa Coagulation Removal

Abstract:

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.

Key words:extracellular organic matter (EOM); coagulation; Microcystis aeruginosa; mechanism