Occurrences and Characteristics of Disinfection By-products in Swimming Pool Water
Date Issued
2011
Date
2011
Author(s)
Lo, Tsu-Ning
Abstract
Chlorination of swimming pool water is an indispensable process to maintain the water quality for prevention of potential health problems. However, the disinfectants react with bather loads (matters carried by the swimmers into the swimming pool water, such as lotions, hair, makeup, sweat, urine. etc), and these reactions produce various contaminants including disinfection by- products (DBPs) such as trihalomethanes (THMs), haloacetic acids (HAAs) and nitrosodimethylamine (NDMA). Previous studies have shown that DBPs are carcinogens, which may have adverse health impacts to the swimmers.
To gain a better understanding of DBPs in pool water, five swimming pools with different types of operations were selected and sampled to assess the relationships between the water qualities, disinfection practices and formation of DBPs. In order to investigate the DBPs concentration change during a day, a whole day sampling of one swimming pool had also been conducted. The DBPs formation potential tests were also conducted to assess the formation of brominated HAAs and THMs formation in pool water. Moreover, a pilot-experiment of ozone treatment and chlorination disinfection was conducted to evaluate the effects of ozonation on the formation of THMs and HAAs. Lastly, chloramination of pool water was investigated to assess the NDMA formation potential.
The results had showed that the DBPs in pool water increased with the number of swimmers, especially the non-volatile HAAs. A higher level of THMs and HAAs was observed in pool water during summer season (HAAs: 90.98-296.52 μg/L; THMs: 28.07-85.24 μg/L), and their levels were apparently decreased in winter (HAAs: 51.24-149.55 μg/L; THMs: 3.85-19.61 μg/L). The presence of higher Br-HAAs concentrations could be a representative parameter to express the contaminated with more of the human substances. Ozone treatment could effectively decrease the THMs in pool water, but the removal of HAAs was poor. The concentration of NDMA would increase after the pool water had been treated with ozone, which might be attributed to the release of more precursors from ozonated impurities, but after increase the contact time with ozone, the level of NDMA was decreased. Continuous filtration of pool water has impact on DBPs formation: it was observed that filtered pool water showed lower level of DBPs formation than the non-filtered pool water (DBPs formation of filtered pool water: HAAs 64.00-91.24 μg/L, THMs 5.09-16.83 μg/L; DBPs formation of non-filtered pool water: HAAs 64.00-94.30 μg/L, THMs 16.40-27.59 μg/L ).
This study had done a long-term investigation to the water quality and two DBPs (HAAs and THMs) in pool water. Furthermore, this study is also the first study in Taiwan to investigate the relation of ozone treatment and DBPs formation in pool water.
Subjects
Swimming pool water
Disinfection by-products (DBPs)
Haloacetic acids (HAAs)
Trihalomethanes (THMs)
Nitrosodimethylamine (NDMA)
Ozone treatment
SDGs
Type
thesis
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