Modeling of secondary treated wastewater disinfection by UV irradiation:Effects of suspended solids content
Mounaouer Brahmi , Noureddine Hamed Belhadi , Helmi Hamdi , Abdennaceur Hassen
DOI:
Received May 10, 2009,Revised December 16, 2009, Accepted , Available online
Volume 22,2010,Pages 1218-1224
- Summary
- References
- Related Articles
This work aimed to study UV-resistant strains of Pseudomonas aeruginosa, to propose a formulation of the kinetics of secondary
treated wastewater disinfection and to underline the influence of suspended solids on the inactivation kinetics of these strains. Some
investigations were carried out for the validation of some simulation models, from the simplest, the kinetics model of Chick-Watson
reduced to first order, to rather complex models such as multi-kinetic and Collins-Selleck models. Results revealed that the involved
processes of UV irradiation were too complex to be approached by a simplified formulation, even in the case of specific strains of
microorganisms and the use of nearly constant UV radiation intensity. In fact, the application of Chick-Watson model in its original
form is not representative of the kinetics of UV disinfection. Modification, taking into account the speed change during the disinfection
process, has not significantly improved results. On the other hand, the application of Collins-Selleck model demonstrates that it was
necessary to exceed a least dose of critical radiation to start the process of inactivation. To better explain the process of inactivation,
we have assumed that the action of disinfectant on the survival of lonely microorganisms is faster than its action on suspended solids
protected or agglomerated to each others. We can assume in this case the existence of two inactivation kinetics during the processes
(parallel and independent) of the first-order. For this reason, the application of a new kinetic model by introducing a third factor
reflecting the influence of suspended solids in water on disinfection kinetics appeared to be determinant for modeling UV inactivation
of P. aeruginosa in secondary treated wastewater.
