| Algae bloom has become a severe problem in China. A lot of techniques were studied on the control of blue algae, one of which is ultrasonic, a physical method with the excellence on simplicity, chemical free and quick effect. In the experiment, the ultrasonic generator was modified to control three major species of algae（microcystis aeruginosa, Anabaena spiroides, and aphanizomenon flos-aquae） causing algae bloom, and the effectiveness and mechanism was reviewed and studied. The ultrasonic of 80 kHz has little effect on algae elimination, while the ultrasonic of 20 kHz has significant reduction effect on all three of them, with Anabaena spiroides removed the most and microcystis aeruginosa the least. The two long-chain algae, Anabaena spiroides and aphanizomenon flos-aquae, are more sensitive to ultrasonic because of chain breaking and the loss of activity, while the spherical algae, Microcystis aeruginosa is broken by ultrasonic based on the cavitation effect. The effectiveness of ultrasonic increased with the increase of power or extention of time, while proper power and time is recommended based on the cost and security issues. The result may provide foundation for the practical use of ultrasonic on blue algae control in the Yangtze River Delta Region. |
