Evaluation of new photochemical systems for water disinfection by the integration of particle tracking into kinetic models for microbial inactivation
This work presents the development of a novel methodology for the simulation of photochemical processes for water disinfection using computational fluid dynamics (CFD). A new approach was implemented to calculate and visualise the disinfection performance as the microorganisms move along the photoreactor. Hydrodynamics and microorganism’s statistical trajectories were computed using the discrete phase model, which also provides the distribution of microbial residence times. The distribution of radiation in the reactor was calculated using the discrete ordinate method. The local values of incident radiation were integrated over each statistical trajectory path to get the accumulated dose received for each microbial particle. The coupling in situ of the cumulative radiation dose with the inactivation kinetics allows monitoring of the disinfection process concurrently with the particle tracking. This methodology introduces significant advantages over the traditional estimation of the microorganism inactivation sequentially after calculating the dose histograms estimated from the statistical trajectories. The developed tool enables evaluating the photoreactor efficiency in each reactor position, a useful capability for optimising and scaling up complex geometries. It also allows the easy, intuitive visualisation of microbial inactivation trajectories, improving the understanding of the influence of the reactor features on the disinfection process. Application of this computational approach to two different photoreactor geometries using a virus as a representative target microbe is presented.
The authors gratefully acknowledge the financial support of the Spanish State Research Agency (AEI) and the Spanish Ministry of Science and Innovation through the project AQUAENAGRI (PID2021–126400OB-C32), the European Union's Horizon 2020 research and innovation programme in the frame of the HYSOLCHEM project (GA 101017928) and the Community of Madrid in the frame of the Multiannual Agreement with the Rey Juan Carlos University "Encouragement for research by young doctors" (M2738 SAFECAT-Agua).
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