Evaluation of disinfection efficiency between sodium hypochlorite and chlorine dioxide on spa water


Sustain. Environ. Res., 21(6), 347-351 (2011)



Ching-Shan Hsu, Wei-Ze Huang and Hsin-Yi Wang


Spa water, chlorine dioxide, sodium hypochlorite, disinfection


Recent government inspections have revealed high microorganism indices in spa water throughout Taiwan. Using spas has become a popular leisure activity because of its recognized health benefits. However, spa water at vacation resorts is often used by numerous visitors. This study compares microbial disinfection effectiveness between chlorine dioxide and conventional chlorine in spa water containing Chinese herbal medicine. Due to the complexity of the compounds in the pool and difficulty in measuring disinfection effectiveness accurately, this study was performed in a laboratory with actual spa water containing Chinese herbal medicine using either chlorine dioxide or sodium hypochlorite. Degradation is then compared by measuring residual chlorine dioxide concentrations and safe disinfection doses in the simulated solution. Regarding total colony forming unit level, the equivalent concentration required for spa water to meet government standards is 0.7 mg L-1 as ClO2 or 1.8 mg L-1 as Cl2. Disinfection efficiencies are 99.4 and 89.5% for chlorine dioxide and sodium  hypochlorite, respectively. Generally, chlorine dioxide is more effective than sodium hypochlorite and is clearly safe. The data in this study can improve the disinfection technology used by related businesses to enhance water quality.

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