Ultrasonic as Green Chemistry for Bacterial and Algal Control in Drinking Water Treatment Source

This paper studied the enhanced effects of ultrasonic as non-chemical oxidant on traditional coagulation of raw water with alum for microorganisms' removal. The treatment processes were studied using ultrasonic frequencies; 20, 40 and 60 KHz at different time intervals namely 15, 30, 45 and 60 minutes. The study revealed that removal percentage of Total Coliform, Faecal Coliform and Faecal Streptococcus ranged between 5% - 46%. There was a positive correlation between ultrasonic intensity, sonication time and bacterial removal. There are clear morphological changes in the algal organisms without cell disruption especially green algae due to the release of photosynthetic pigments "Chlorophyll". No changes of chlorophyll "a" content were detected. Pre-treated samples with 20, 40, and 60 KHz ultrasonic frequencies for 60 min decreased the alum dose by 6.7 %, 13.3 % and 20 % respectively.