"A New Model for the Kinetics of Bacteria Disinfection with UV Radiation "

MARISOL LABAS; CARLOS A. MARTIN; ALBERTO E. CASSANO

San Diego (California-USA)

Conferencia; The Ninth International conference on TiO2 Photocatalysis: Fundamentals and applications (TiO2-9) and the tenth International conference on Advanced Oxidation Technologies for Water and Air Remediation (AOTs-10); 2004

Microbiological contamination of water has always been a problem of general concern. Among the proposed ways to deal with this type of pollution without the known difficulties associated with the use of chlorine, UV radiation is an established technology.This work presents a detailed kinetic study of the rate of removal of bacteria employing UV radiation (253.7 nm) under the following conditions: (i) the indicator microorganism is Escherichia coli, (ii) temperature is 20° C, (iii) four different irradiation levels are employed (iv) the initial concentration of bacteria varies from 105 to 108 CFU cm-3, (v) two different culture medium are used and (vi) the concentration of the culture medium varies between 10-3 to 10-6 g cm-3. The three last variations were introduced to simulate typical effluents from food industries and clean waters for domestic use.The study was carried out in a well-stirred reactor of cylindrical shape irradiated from both flat sides with two tubular lamps placed in the axial position of two parabolic reflectors. The reactor was operated in a recycle . The concentration evolution was analyzed employing the plate count method with Petrifilm specific plates. The Incident Radiation at the reactor windows was measured with ferrioxalate actinometry. One of the most important conclusions of this work is the observed reaction order with respect to the volumetric rate of radiation absorption by the bacteria. This result may have very important economical consequences.