Cost-effectiveness analysis of chlorine-based and alternative disinfection systems in pool waters

Abstract

[eng] The aim of this study was to ascertain the biocidal efficacy, based on the so-called C·t values, and the usage expenses of seven disinfection products in recreational waters using Escherichia coli and Pseudomonas aeruginosa as microorganism models of fecal and environmental contamination, respectively. A 250-L indoor fully equipped pool basin was harnessed as a proof-of-concept setup for the evaluation of chlorine-based [viz., trichloroisocyanuric acid (trichloro), sodium hypochlorite, sodium hypochlorite + isocyanuric acid, and saline electrolysis] and unconventional (viz., 1-bromo-3-chloro-5,5-dimethylilhidantoine, chlorine dioxide and hydrogen peroxide) biocides at 30°C and different pH values. The economic losses resulting from human action, mimicked by urea addition, were also considered. Experimental results showed that trichloro, chlorine dioxide, and sodium hypochlorite were the most effective disinfection agents with a log 3 removal of both organisms in 60 s regardless of the water pH. On the other hand, sodium hypochlorite and trichloro afforded unparalleled cost-effectiveness. Chlorine dioxide exhibits the greatest biocide efficacy, yet its elevated usage costs make it merely applicable in shock treatments to offset high organic loads.