Modelling of reactivation after UV disinfection: effect of UV-C dose on subsequent photoreactivation and dark repair |
| |
Authors: | Nebot Sanz E Salcedo Dávila I Andrade Balao J A Quiroga Alonso J M |
| |
Affiliation: | Department of Chemical Engineering, Food Technologies and Environmental Technologies, Faculty of Marine and Environmental Sciences, University of Cádiz, Cadiz, Spain. enrique.nebot@uca.es |
| |
Abstract: | The increased use of UV radiation as a wastewater treatment technology has stimulated studies of the repair potential of microorganisms following treatment. In this study, samples of unfiltered secondary effluent were irradiated with seven levels of UV-C doses (50-200 mW s/cm(2)) from six low-pressure lamps in an open-channel UV disinfection system. Following irradiation, samples were incubated at 20 degrees C under photoreactivating light or in darkness. Samples were analysed for 240 min following incubation. The logistic model is proposed to explain the relation between photoreactivation and the UV-C dose received by the microorganisms. That model accurately fitted the data obtained in photoreactivation experiments, permitting interpretation of the estimated kinetic parameters: S(m) and k(2). In the experiments carried out in darkness, a slight reactivation is observed (<0.1%), followed by a decay period in which survival decreases. In order to model this last period, a modification was made to the logistic model by including a term of mortality that assumes a zero-order kinetic. The parameters S(m) and k(2), in both photoreactivation and darkness, show an exponential dependence on the UV-C inactivating dose. It is possible to predict their values, and hence the reactivation curve, from the equations proposed in this work. |
| |
Keywords: | Ultraviolet irradiation Photoreactivation Dark repair Wastewater Faecal microorganisms Model |
本文献已被 ScienceDirect PubMed 等数据库收录! |
|