Singing Algae to Sleep: Understanding the Use of Ultrasound for Algal Control

摘要

The use of ultrasound technology to treat algal blooms is a relatively newoption for water companies which have a huge potential as an alternative tochemical water treatment. It works by concentrating the energy of soundwaves through cavitation causing the compression, rarefaction, and finallyimplosive collapse of bubbles in a liquid).This collapse by cavitation producesintense local heating (5,000℃) and high pressure (2000 atm) and is veryshort lived. Numerous studies have been carried out on cyanobacterialspecies and ultrasound but a comprehensive study using ultrasound on all theproblematic species concurrently has not been completed to date. The aim ofthis study was to reproduce a comprehensive catalogue of the effect thatUltrasound has across all problematic blooming algal species. A range of algalspecies were tested including cyanobacteria species Microcystis aeruginosaand Aphanziomenon flos-aquae, a green alga Scenedesmus subspicatus anda wild type diatom Melosira sp. The experiments were performed usinglaboratory scale Ultrasonic equipment covering frequencies between 20 kHzand 1.15 MHz, and power ranges of 200-420Watts.