A study on the effect of pulsed power ultrasound waves on marine biofouling

Abstract

<span style="font-size:9.0pt;line-height: 115%;font-family:" times="" new="" roman";mso-fareast-font-family:calibri;mso-bidi-font-family:="" "times="" roman";background:white;mso-ansi-language:en-us;mso-fareast-language:="" en-us;mso-bidi-language:ar-sa"="" lang="EN-US">Ultrasonic technique is one of the promising non-invasive technologies to control biofilm formation on the marine substratum. A prototype ultrasonic system was designed and developed to control biofouling in the marine environment. The Ultrasonic technique was utilized to control the biofilm formation on copper test coupons suspended in a continuous seawater flow through system. The colonization of microorganisms promotes settlement of higher order organisms; therefore, deactivation of microorganisms is likely to affect the fouling density. <span style="font-size:9.0pt;line-height: 115%;font-family:" times="" new="" roman";mso-fareast-font-family:"times="" roman";="" mso-bidi-font-family:"times="" roman";mso-ansi-language:en-us;mso-fareast-language:="" en-us;mso-bidi-language:ar-sa"="" lang="EN-US">Ultrasonic sound waves at 25 kHz with an electric drive power of 500 watts were used to control aquatic biofouling and growth in an open seawater circulation experimental setup. The ultrasonic waves create microscopic cavitations which damages the outer cell structure of microorganisms destroying them and preventing them from growing around the ultrasound exposure areas.<span style="font-size:9.0pt; line-height:115%;font-family:" times="" new="" roman";mso-fareast-font-family:calibri;="" mso-bidi-font-family:"times="" roman";background:white;mso-ansi-language:en-us;="" mso-fareast-language:en-us;mso-bidi-language:ar-sa"="" lang="EN-US"> The experiments were conducted continuously over a period of 21 days and were repeated several times to ensure reliability. A reduction in the microorganism activation was observed on the ultrasound exposed area besides preventing damages to the structure of the test coupon. Based on the encouraging results, a low cost prototype ultrasonic digital system controlled by pre-programmed microchips was custom built and the same is being planned for further studies in the frequency range 20 – 40 kHz. </span></span></span>