In this paper,the fluorescent characteristics of intracellular and extracellular dissolved organic matters of Microcystis aeruginosa were investigated by means of the EEM ( Excitation Emission Matrix) fluorescence spectroscopy,and the inactivation mechanism of Microcystis aeruginosa by chlorination and UVC irradiation was analyzed according to the cyanobacterial biochemical indexes such as the contents of total protein,phycocyanin,chlorophylla
and microcystin-LR. The results indicate that ( 1) the characteristic materials associated with Microcystis aeruginosa are mainly protein-like matters corresponding to peaks A and B and humic-like matters corresponding to peaks C and D; ( 2) the inactivation of Microcystis aeruginosa by UVC irradiation is mainly due to the photodegradation and advanced oxidation; ( 3) after a UVC irradiation for 60 min,the intracellular protein-like matters are transformed into extracellular humic-like ones,and few residuals are found after 120min; ( 4) the removals of phycocyanin and microcystin-LR respectively reach 83.55% and 94.70% after 30 min,while the removals of total protein and chlorophyll-a are relatively low; ( 5) the inactivation of Microcystis aeruginosa by chlorination is mainly due to the chemical ablation and degradation of cyanobacteria cells by the permeated HClO; ( 6) after a chlorination for 60 min,both the intracellular and the extracellular protein-like matters decline with significant remain of extracellular humic-like matters; ( 7) the removals of phycocyanin and total protein respectively reach 96. 44% and 60. 36% after 30min,while the removals of microcystin-LR and chlorophyll-a are relatively low; ( 8) the UVC irradiation with medium intensity is effective in the removal of cyanobacteria and the purification of dissolved organic matters; and ( 9) the HClO permeated into cyanobacteria cells is also effective in the removal of cyanobacteria but is ineffective
in the purification of dissolved organic matters.