Variability of residual chlorine in swimming pool water and determination of chlorine consumption for maintaining hygienic safety of bathers with a simple mass balance model.

Alvyn P Berg,Ting-An Fang,Hao L Tang

doi:10.2166/wh.2018.217

Alvyn P Berg, Ting-An Fang + Show 1 more

Open Access

https://doi.org/10.2166/wh.2018.217

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Abstract

Trial-and-error chlorination as a conventional practice for swimming pool water disinfection may fail to consistently maintain the pool's residual chlorine within regulatory limits. This study explored the variability of residual chlorine and other common water quality parameters of two sample swimming pools and examined the potential of using a mass balance model for proactive determination of chlorine consumption to better secure the hygienic safety of bathers. A lightly loaded Pool 1 with a normalized bather load of 0.038 bather/m3/day and a heavily loaded Pool 2 with a normalized bather load of 0.36 bather/m3/day showed great variances in residual free and combined chlorine control by trial-and-error methods due to dynamic pool uses. A mass balance model based on chemical and physical chlorine consumption mechanisms was found to be statistically valid using field data obtained from Pool 1. The chlorine consumption per capita coefficient was determined to be 4120 mg/bather. The predictive method based on chlorine demand has a potential to be used as a complementary approach to the existing trial-and-error chlorination practices for swimming pool water disinfection. The research is useful for pool maintenance to proactively determine the required chlorine dosage for compliance of pool regulations.

Highlights

Swimming is considered a health-enhancing and relatively injure-free physical activity, and attracts people of all ages
The normalized bather load was 0.038 bather/m3/day
The results suggest that it is possible to proactively determine the chlorine dosage with the mass balance model based on the predictive number of bathers and the chlorine consumption per capita coefficient

Summary

INTRODUCTION

Swimming is considered a health-enhancing and relatively injure-free physical activity, and attracts people of all ages. Maintaining a required residual chlorine concentration in swimming pool water at all times for hygienic safety of bathers is both challenging and necessary, and represents an important area of research. The residual chlorine maintaining practice needs to consider the chlorine consumption mechanisms This is important for compliance of pool regulations, reduction of disinfection byproducts formation, and economization of free chlorine usage. Since the use of trial-and-error methods for residual chlorine control is reactive, it would be desirable to have an unconventional method that can proactively determine the chlorine consumption in swimming pools. This would help in reducing the occurrence of disinfectant level violations and better securing the hygienic safety of bathers. The research would improve existing understanding about chlorine consumption in swimming pools and help pool management determine required chlorine for compliance of pool regulations

MATERIALS AND METHODS

RESULTS AND DISCUSSION

CONCLUSIONS