Fluorescent Characteristics Of Oxidation Effect And Disinfection By-products Of Algae

The problems bought by algal in drinking water resousesinclude undesirable taste, odorand colority, so algae removal is an important task for water supply. In this paper, anine-month investigation about algae species distribution in a reservoirs and the feasibilitystudy about using fluorescence spectrum to counting cell density were implemented. Also,Microcystis aeruginosa was used for investigate the fluorescent characteristics duringoxidation processes and its correlation with other indicators. Compositions and formationcharacteristics of disinfection by-products were studied in particularly. And, fluorescencecorrelation analysis of bromoform (CHBr3) precursors was carired. The main researchpurpose of this paper is to develop a quick and effective algae examination and countingmethod on site by fluorescence analysis and to provide a scientific basis for the removal ofalgae. The main research results and conclusions of this paper are as follows:(1)In a reservoir, cyanobacteria in the fall as the dominant species, accounting for morethan55%; Microcystis aeruginosa and Oscillatoria tenuis are most common. In winterdiatoms were the dominant species, more than86%; which Cyclotella sp. most common. Inspring succession of dominant species is more complex, as temperatures rise, diatom ratiodecreased from88.7%to42.8%, while the the green algae proportion gradually increased to44.3%, Chlorella pyrenoidosa is more common in green algae. Due to high temperatures inthe summer, mainly to blue-green algae, and M aeruginosa is the largest number.(2)The fluorescence spectra of the different types of algae will vary, which makes itpossible to fluorescence of algae count. This paper first attempt using fluorescence of likeprotein area combine with fluorescence of pigment area to counting cell density, like Maeruginosa, Cyclotella sp., C. pyrenoidosa, O. tenuis. The method can better quantitative M.aeruginosa, Cyclotella sp. and C. pyrenoidosa, but for O. tenuis is not applicable. Further, themethod when the algae density of3x104to7x105/mL/mL within good accuracy.(3)Ozonation and UY irradiation on the algal cells have a significant removal effience,and the effience of ozonation is better than the effience of UY irradiation. After adding ozone, the fluorescence intensity of pigment area and like protein area decreased; UY irradiationresults similar to ozone oxidation. There is a good relationship between the fluorescenceintensity of peak T and Zeta potential, SOD activity. There is a good relationship between thefluorescence intensity of pigment area and the concentration of chlorophyll-a.(4)With hypochlorous acid disinfection byproducts formation potentialexperimental comparison, the free bromine bromine disinfectant to participate inchange of disinfection by-products to generate brominated disinfection byproducts, butbromine disinfectants and disinfectant algaecide total trihalomethanes molar concentration similar.Dibromoacetonitrile and bromoform bromine disinfectant byproducts. Trihalomethaneformation increases with pH, halogen acetonitrile hydrolysis to generateconcentration reduced with the increase of pH. So there may be one of the best pHbalance THMs generate base-catalyzed reaction and Hans hydrolysis of base-catalyzedreaction byproducts minimal toxicity.(5)Correlation between the fluorescence spectra and the formation concentration ofdisinfection by-product precursors. The fluorescence intensity of like humic acid increasedwith the concentration of disinfection byproducts increased. The fluorescence intensity oflike humic acid are and BF were positively correlated (P <0.05).