Physicochemical aspects of disinfection of water by means of ultrasound and ozone

20 kHz-ultrasonic waves intensify the ozonation process in regard to disinfection of microorganisms, as well as to oxidation of organics. Ultrasonic treatment of effluent from biological sewage plant, reduced the sterilization dose of ozone with 50%, and increased the half order rate constant of decoloration of Rhodamine B with 55%.The phenomena is attributed to the action of two physicochemical mechanisms. (1) Ultrasound decomposes ozone causing augmentation of the activity of free radicals. (2) Simultaneous ultrasonic treatment enhances the aeration constant, (KLα-value).

Both mechanisms increase the gas liquid ozone transfer and the utilization of the applicated ozonated gas.It is verified that free radicals are the proper disinfective and oxidative agents in ozonation and sonozonation. Ozone molecules act as precursors and may in themselves be relatively nontoxic.