Kinetics of bacteria disinfection with UV radiation in an absorbing and nutritious medium

MARISOL D. LABAS, CARLOS A. MARTÍN, ALBERTO E. CASSANO

CHEMICAL ENGINEERING JOURNAL

Año: 2005 vol. 114 p. 87 - 97

1385-8947

A kinetic model for water disinfection employing UV-C radiation (ë = 253.7 nm) was developed that is valid for clear waters as well as for aconcentrated and nutritious medium. Escherichia coli was used as a test bacteria. The kinetic model is a modification of the series event inactivationmathematical description that takes into account the radiation absorption rate corresponding to the existing, viable bacteria and the radiationattenuation produced by the quasi-transparent or the translucent environment. It also explains two additional observed phenomena: (i) the effect ofbacteria growth in the nutritious medium during disinfection and (ii) a further reduction in the inactivation rate that was attributed to some form ofbacteria protection produced by a not well understood association of the bacteria with of the components of the concentrated culture. Comparingtheoretical predictions from the model with experimental concentration versus time data, the model parameters were obtained. Predictions showgood agreement with collected experimental data within the range of the explored variables.