An exploration of disinfection by-products formation and
governing factors in chlorinated swimming pool water
Huma Ilyas, Ilyas Masih and Jan Peter van der Hoek
ABSTRACT
This paper investigates disinfection by-products (DBPs) formation and their relationship with
governing factors in chlorinated swimming pools. The study compares concentrations of DBPs with
WHO guidelines for drinking water quality recommended to screen swimming pool water quality.
The statistical analysis is based on a global database of 188 swimming pools accumulated from
42 peer-reviewed journal publications from 16 countries. The mean and standard deviation of
dichloroacetic acid and trichloroacetic acid were estimated as 282 ± 437 and 326 ± 517 μgL
1
,
respectively, which most often surpassed the WHO guidelines. Similarly, more than half of the
examined pools had higher values of chloral hydrate (102 ± 128 μgL
1
). The concentration of total
chloramines (650 ± 490 μgL
1
) was well above the WHO guidelines in all reported cases.
Nevertheless, the reported values remained below the guidelines for most of the studied pools in the
case of total trihalomethanes (134 ± 160 μgL
1
), dichloroacetonitrile (12 ± 12 μgL
1
) and
dibromoacetonitrile (8 ± 11 μgL
1
). Total organic carbon, free residual chlorine, temperature, pH,
total nitrogen and bromide ions play a pivotal role in DBPs formation processes. Therefore, proper
management of these governing factors could significantly reduce DBPs formation, thereby,
contributing towards a healthy swimming pool environment.
Huma Ilyas (corresponding author)
Ilyas Masih
Water Treatment and Management
Consultancy B.V.,
2289 ED Rijswijk,
The Netherlands
E-mail: hi.wtmconsult@gmail.com
Ilyas Masih
IHE Delft, Institute for Water Education,
2611 AX Delft,
The Netherlands
Jan Peter van der Hoek
Department of Water Management, Faculty of Civil
Engineering and Geosciences,
Delft University of Technology,
2600 GA Delft,
The Netherlands
and
Strategic Centre, Waternet,
1096 AC Amsterdam,
The Netherlands
Key words | best practices, chlorination, disinfection by-products, global database, swimming pool
water, WHO guidelines
INTRODUCTION
Swimming is popular among people of all ages and income
groups, as it can provide health benefits such as enhanced
lung functions and less respiratory symptoms, especially
among asthmatic children (Font-Ribera et al. ). Swim-
ming pool activities are also beneficial for the
development of physical fitness and water orientation for
autistic children (Yilmaz et al. ). Considering the posi-
tive aspects of swimming, regulators, service providers and
researchers have turned their attention to maintaining
hygiene and bio-chemical water quality. Progress in the
treatment of swimming pool water has made it an admired
activity for leisure as well as exercise (Zwiener et al. ).
However, swimming pool water receives a wide variety
of pathogenic micro-organisms (viruses, bacteria, protozoa
and fungi). There are a number of different routes by
which these micro-organisms may be delivered: direct
excretion by bathers, transport on the body or growth
within the filter bed (Bonnick ). Therefore, the disinfec-
tion of swimming pool water is essential to maintain the
encouraging aspect of aquatic activities, hygienic safety
and protection of swimmers against infectious diseases
caused by pathogenic micro-organisms (Lee et al. ;
Schmalz et al. ).
In practice, chlorination is the most commonly used
method of disinfection in recreational water settings,
aimed at the prevention of waterborne diseases and
inactivation of pathogenic micro-organisms in swimming
pools (Chowdhury et al. ). The chemicals used for
861 © IWA Publishing 2018 Journal of Water and Health | 16.6 | 2018
doi: 10.2166/wh.2018.067
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