Study On The Ecological Restoration Rroject Of Microcystis Bloom

From the In late twentieth Century, the eutrophication is becoming more and more serious. A number of algal bloom disasters occurred in lakes, rivers and ocean time to time, leading to a series of environmental problems, and seriously affected the production and life of human beings and the protection of water resources. Microcystis aeruginosa is the most common freshwater algae bloom. When Microcystis bloom just happen or break out, we need to take effective emergency measures to control it.The chemical method is a commonly used method to control the Microcystis bloom, but algaecide often has strong toxicity, may cause greater harm to the ecosystem and the environment. Therefore, algaecide were studied to determine the optimal concentration, algae removal and biological toxicity,which has great realistic significance for the scientific control of Microcystis bloom.Ultrasonic technology has been regarded as a safe and environmentally friendly means of control of algae. In this paper, using ultrasonic destructive effect on the structure of algal cells and inhibition of Microcystis aeruginosa growth in two aspects of the role, through the single factor experiment and response surface experiments of two kinds of experimental methods, the ultrasonic response of Microcystis aeruginosa removal and to study the effect of inhibiting the growth and provide experimental support and scientific basis for the ultrasonic inhibition Microcystis bloom.According to the results of the experiment, we can determine that the best inhibitory concentration of glutaraldehyde is about 5 mg/L, the removal rate of algae was 75.31%; the best inhibitory concentration of hexadecyl trimethyl ammonium bromide optimal is about 2 mg/L, the removal rate of algae was 73.62%; the best inhibitory concentration of isothiazolone is 2mg/L, the removal rate of algae was 80.43%; the optimal concentration of algae inhibition of 2-methyl-ethyl-acetoacetate was 7mg/L, the removal rate of algae was 54.90%; the best inhibitory concentration of copper sulfate was 1.5mg/L, the removal rate of algae was 76.84%. Acute toxicity experiment on koi showed that the 96hLC50 and the highest concentration of no death of 5 kinds of algaecide were: 6.33 mg/L,3.67 mg/L,5 mg/L; 2 mg/L; 0.83 mg/L,0.25 mg/L; 19 mg/L;>20 mg/L,3.29 mg/L,2 mg/L.Both of the single factor experiment and response surface experiments of immediate removing Microcystis aeruginosa by ultrasonic were carried out. In addition to the single factor determining irradiation time 20-60min, frequency 20kHz, power 60W as the best parameters. Through the response surface experiment a two order mathematical model fitting was obtained. According to the fitting results, when the frequency of 20kHz, power was 58.67W, irradiation time was 58.03min, the immediately removal rate of algae immediately have a maximum of 17.58%.And then both of the single factor experiment and response surface experiments of controling the growth of Microcystis aeruginosa by ultrasonic were carried out.The single factor experiment showed when the radiation time was between 20 and 60min, power was 60W, and the frequency was between 50 and 80kHz. the removal rate of Microcystis aeruginosa reached the maximum.The mathematical model of ultrasonic to inhibit the growth of Microcystis aeruginosa were determined by response surface experiments. When the frequency was 74.47kHz,the power was 53.65W,the irradiation time was 54.17min, the removal rate of Microcystis aeruginosa have a maximum of 85.14%.When laboratory experiments were completed, the scale-up experiment of glutaraldehyde was carried out. Experimental results showed that, the inhibiting ability on Microcystis aeruginosa of glutaraldehyde was good. The maximum removal rate of chlorophyll A reached 61.4%, the removal rate of Microcystis aeruginosa reached about 55%.Finally, in addition the scale-up experiment of ultrasonic to inhibit Microcystis aeruginosa was carried out. Results showed that ultrasonic had a certain removal and inhibition effect on Microcystis aeruginosa. The largest algae removal rate reached 53.73.