Variation Of Assimilable Organic Carbon During Pre-oxidation Of Algae-containing Water With Chlorine And Potassium Permanganate

The rapid development of national economy and industry, a large number of untreated sanitary sewage and industrial wastewater discharged into lakes and reservoirs, causing increased nitrogen, phosphorus and other nutrients. The seasonal algae bloom led to serious eutrophication problem and affected the drinking water biological stability. Algal organic matter(AOM) was typically classified into the extracellular organic matter(EOM) and intracellular organic matter(IOM).In this paper, using microcystis aeruginosa as the research object. The method of AOC concentration was based on the flow cytometer, which is a new method. This research is to get the variation of oxidize algal-containing water、EOM and IOM with chlorine, to assess the influence of various water quality of chlorine oxidation process and to learn more about potassium permanganate oxidized algal-containing water with EPS or without EPS. The research is to study the variation of assimilable organic carbon(AOC) during pre-oxidation of algal-containing water with chlorine and potassium permanganate.The results showed that chlorine could lead to a rapid decrease of the integrity of algal cells, destruct algal cells structure, release IOM and increase AOC concentration. Meanwhile the release of potassium could as a good indicator. The increase of AOC concentration was owed to two aspects. One was that algae cells were destructed by oxidants and in this process AOC was released into the water, and another was that AOM was oxidized.EOM was mainly composed of two kinds of material, namely soluble microbial by-product and humic acid. While IOM had four typical EEM peaks, separately represented soluble microbial by-product,aromatic protein, humic acid and fulvic acid. The emergence of fulvic acid can be characterized the release of IOM. Before oxidation, AOC concentration of IOM was much higher than EOM. The release of IOM could increase AOC concentration.The fluorescence intensity of EOM and IOM had no significant change with chlorine of 1mg/L. In the process of oxidation of algal-containing water, AOC concentration increased rapidly at first, and then decreased slightly. When the dosage was 3mg/L, AOC concentration increased rapidly too, but then reduced gradually. No matter chlorine dosage or oxidation time increased, EOM only have very small contribution to AOC concentration.The increase of EOM concentration had no effect to the ability of oxidation with chlorine, but IOM concentration raised show a inhibiting effect. With the increase of raw water, settled water and filtered water concentration, inhibiting effect, no effect and inhibiting effect, respectively.Potassium permanganate oxidized algal-containing water with EPS showed that the number of algal cells reduced gradually, oxidation time increased and AOC oncentration raised. This is caused by potassium permanganate was oxidized to a newly formed hydrous manganese dioxide in the process of oxidation. And extracelluar polymeric substances(EPS) is mainly composed of polysaccharides and proteins.With the increase of potassium permanganate dosage, algal-containing water with EPS and without EPS also had the decrease of the integrity of algal cells, but the former AOC concentration increased at first and then decreased, the latter increasing constantly.