INVESTIGATION OF WATER TREATMENT PROCESSES USING CHLORINE DIOXIDE:2. MATHEMATICAL MODELLING AND OPTIMIZATION

Abstract

The present article assesses the technological feasibility of introducing chlorine dioxide as an alternative disinfection agent in centralized water supply systems of Ukraine, taking into account operational risks arising from damage to infrastructure and a decrease in the quality of source water during military operations. An approach based on mathematical and computer modelling of water treatment processes is applied; for the chlorine-dioxide-based disinfection technology, optimal reagent dosing conditions were identified to minimise the formation of disinfection by-products. Based on experimental data, quadratic polynomial experimental–statistical models were developed to describe the fraction of reacted chlorine dioxide and the concentration of chlorites in disinfected water.

The input data for the parametric identification of the models were obtained from an active multifactor experiment conducted using a central composite rotatable design (technological factors included pH, water temperature, reagent dose, reaction contact time, and the content of organic matter in natural water).

To determine optimal operating conditions, multi-objective optimization was performed using the Harrington desirability function. This made it possible to find a balance between maximizing disinfection efficiency and minimizing by-product formation. The proposed approach enables the use of the models as digital twins of the technological treatment line and supports the justification of reagent dosing under varying raw water quality conditions. The findings of the study may serve as a basis for modernizing water treatment systems and implementing adaptive chlorine dioxide dosing at water utilities in Ukraine.