Study On Trichloromethane Formation And Reduction Mechanism In Swimming Pool Water

In recent years, with the development of city and the improvement of people’s living standards, choosing the swimming pool as a daily place for entertainment and fitness reflect the high quality of life. In order to ensure the water quality of swimming pool and avoid different kinds of disease outbreaking, we usually use chlorinated disinfectant to kill pathogenic microorganisms in water quickly, effectively and continuously. But when the chlorine play a role in disinfection, it can also react with different kinds of organic matters to produce chlorinated disinfection by-products(DBPs). The health hazards of DBPs to swimmers has been confirmed by scientists and began to be concerned. Trichloromethane(TCM) as one of typical DBPs has carcinogenic, teratogenic and mutagenic properties.It can harm human’s liver, kidney, reproduction and other organs through some exposed way such as breathing, swallowing, skin absorption and so on.Currently, FINA, some developed countries and our country have also formulated for swimming pool water quality standard limits of TCM. But the study on formation mechanism and control method of TCM in swimming pool water is rarely reported. In order to study the effects of TCM formation by the characteristics of swimming pool water quality and other factors, and explore the measures to lay the theoretical foundation for health risk reduction that TCM brought to swimmers. This research through the analysis of TCM precursors in swimming pool water, use the components which classificated after physical and chemical to chlorination reaction for determination of chloroform generating potential, and do simulation studies of the factors to reveal the correlationship between precursor concentration、chlorine dosage、 reaction time and the TCM concentration, to explore the TCM formation and reduction mechanism.The main results are as follows:1) The physical characteristics of the main TCM precursors in swimming pool water is MW in 1k-3k Da. Both of the generative contribution and capacity of TCM by the organic matter in 1k-3k Da are the highest of all the organic matter.2) The chemical characteristics of the main TCM precursors in swimming pool water is hydrophobic acid. Both of the generative contribution and capacity of TCM by HPOA are the highest of all the organic matter. HPIM has a high degree of the generative contribution of TCM.3) To some extent, the SUVA value can reflect the TCM generating capacity of precursors in swimming pool water.4) When the dosage of chlorine is sufficient, precursor concentration is positively correlated with TCM generation. The saturation ratio of effective chlorine and precursor’s DOC is between 4:1~5:1. When the precursor and the dosage of chlorine is sufficient, the TCM concentration grow in number with the sterilization time increasing.5) The generating rate of TCM is the fastest at 1~9 hours after chlorine. To deal with organic precursors when an hour before cast chlorine can effectively reduce the generation of TCM.