| With high speed development of the economy and population, the quantity of water we used and let is also increasing every year. The problem of wastewater treatment becomes more and more important, and feedwater issue gets widespread attention. One of these numerous water treatment methods is flocculation-sedimentation, which is a method both economical and simple used in domestic and foreign at present. In the tradition flocculants, the iron, aluminum and the polyacrylamide class flocculants, which are widespread used, can cause environmental pollution, and exist latent harm to the human health, is easy to induce old age dementia, cancer and other disease. The microbial flocculant is the natural biomacromolecule flocculant, which is harmless to the human body, easily biodegradation, does not pollute the distiller's grain feed, does not have the adverse effect to the ecological environment, and the flocculation effect is very good, thus at present has become the environment project domain search hot spot.This thesis is research in the foundation to filtrate a fungus which can produce flocculant from the soil and the active sludge, then have a preliminary study on the microbial flocclant activity, application and the action mechanism. The concrete research and results of this thesis are as follows:1. 46 pure plants have been separated from the soil and active sludge, then after first sieves and second sieves. The fungus MBF-GL separated from active sludge produce flocclant activeness is highest, and the flocculating rate reaches to 84.2%. By the appraisal, MBF-GL belongs to Penicillium Verruculosum. Take it as the experiment object.2. Studied the effect of different fungus age, inoculation quantity, carbon source, nitrogen source, temperature, initial pH value and osmotic pressure on fungus MBF-GLD bioflocculant production. Then design the orthogonal experiment on the base of single factor experiment. Get the MBF-GLD flocculant optimized condition is: NaCl density is 3%, carbon source is the sucrose, nitrogen source is the ammonium-sulfate, and the nutrient fluid initial pH value is 7.3 . Studied the effect of the quantity of bioflocculant adding, the flocculation system temperature, flocculation system pH value, whisking speed and metallic ion on flocculating rates. Then design the orthogonal experiment on the base of single factor experiment. Get the bioflocculant optimized flocculation condition in the kaolin fluid is: The quantity of bioflocculant adding is 0.5mL·100mL-1, the flocculation system temperature is 50℃, the flocculation system pH value is 10, and whisking speed is 450r·min-1.4. Applied MBF and PAM to the water treatment, contrasts them flocculation effects: (1) In the kaolin fluid flocculation experiment, the MBF flocculation rate is 93.1%, and the PAM flocculation rate is 86.6%. (2) In the starch ethyl alcohol wastewater treatment experiment, the effect of MBF removes COD is inferior to PAM, but its effect in decolorization and removing the suspension surpass PAM. (3) In the syrup purifying experiment, the MBF has similar effect with PAM in sedimentation rate, decolorization and removing the suspension.5. By mensurating the MBF active constituent distribution, discovered the active constituent mainly exists in the fermentation fluid serum. And the effective component mainly is multi-carbohydrates matter.6. Studied the bioflocculation mechanism: Under the agitation, the Brownian movement and vanderWaals force, macro-molecules overcome the static electricity repelling force to make the flocculant molecule and suspended granule pelletmutually approach . And the flocculant macro-molecule simultaneously adsorbs many inorganic or colloid pellet with the aid of the ionic bond, there has bridge association phenomenon in the wadding substance between, thus forms the big pellet rapid subsidence to get down.7. To protract the absorbance curves diagram changed with time under the ultraviolet-visible light iuxmeter in dynamics scanning procedure, and infer thedynamic equation :...
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