Improving Water Treatment Efficiency at Thermal Power Plants Through the Implementation of Resource-Efficient Technologies

Abstract

Water treatment systems based on sodium–cation exchange are widely used at thermal power plants. However, their operation is associated with high consumption of water and sodium chloride during regeneration and the generation of highly mineralized wastewater. This study proposes an integrated approach to improving the performance of sodium–cation exchange water treatment systems by combining regeneration wastewater recycling with optimization of filter operating conditions. Experimental investigations were carried out to evaluate regeneration wastewater composition, changes in chloride concentration and total hardness during filter washing, and the efficiency of soda-lime softening for subsequent reuse of the treated solution in a closed regeneration cycle. A mathematical method describing concentration-front propagation within the ion-exchange bed under non-equilibrium conditions was developed to determine the actual working capacity of the resin and predict filter cycle duration at different filtration rates. The model was verified against experimental data and implemented as software for automated calculation of operating parameters. The proposed closed-loop regeneration scheme enables reuse of treated regeneration solutions, reduces sodium chloride consumption, and decreases the discharge of highly mineralized wastewater. The developed calculation method provides a basis for selecting rational operating conditions, improving utilization of ion-exchange resin capacity, and reducing water and reagent consumption. The combined application of wastewater recycling technology and the proposed calculation approach improves the operational, economic, and environmental performance of water treatment systems at thermal power plants. In this paper, the presented calculations are combined with experimental characterization and treatment of regeneration wastewater with soda and lime, selective extraction of concentrated regeneration fractions, their return to the regeneration cycle, and the selection of operating conditions based on calculations within a unified resource-efficient water treatment scheme. The integrated assessment of filter performance with treatment and reuse of regeneration wastewater is the novelty of this study.