Influence of ultrasonic field on microcystins produced by bloom-forming algae

Sonic cracking of blue-green algae

“…The quick decrease in live algae is similar to that in previous studies [12][13][14][15][16][17]. We assume that the correlation between (high) frequency and algae eradication in these studies is related to the ultrasound proximity to heterocyst resonance as well.…”

“…Therefore, ultrasonic algae control has been under investigation [12][13][14][15][16][17]. In [12][13][14][15][16][17], ultrasonic insonification of different species of algae led to a decrease in algae concentrations in the frequency range 20 kHz-1.7 MHz, which is in contrast with [18], where ultrasound was observed to strengthen the cell membranes of red algae. In these studies, the exact acoustic conditions have not been specified other than the frequency and power input.…”

The effects of ultrasound on cyanobacteria

“…Author (year) Algal species Ultrasonic frequency and intensity Volume Time (min) Effectiveness Simon (1974) Anabaera cylindrica Not reported; 1000 W cm À3 100 mL 2 75% protein released Tang et al (2003) Spirulina plantensis 1.7 MHz; 0.6 W cm À3 Not reported 9 Inhibition of growth Hao et al (2004) Spirulina plantensis 1.7 MHz; 0.07 W cm À3 800 mL 5 $50% reduction 20 kHz; 0.014 W cm À3 33.33% reduction Mahvi and Dehghani (2005) Cyanobacteria 42 kHz; 0.07 W cm À3 1000 mL 2.5 100% reduction Zhang et al (2006b) Microcystis aeruginosa 20 kHz; 0.08 W cm À3 1000 mL 10 14.29% reduction 1320 kHz; 0.08 W cm À3 55% reduction Joyce et al (2010) Microcystis (Ma et al, 2005). Using ultrasound at an intensity of 0.03 W cm À3 at 20 kHz, 150 kHz, 410 kHz and 1.7 MHz the results indicated that intermediate frequencies had an improved effect on microcystin degradation.…”

Removal of blue-green algae using the hybrid method of hydrodynamic cavitation and ozonation

“…Also, jet cavitation effectively inhibited the growth of Microcystis aeruginosa where the inhibition strongly depended on the hydraulic characteristics of the cavitation tube, inlet pressure, cavitation number, light and different algal concentrations [37]. However, it should be noted that the cavitational process also caused the release of microcystins into the water [38,39].…”