DUGi

Efecte de l’ozonització en la formació de trihalometans durant el tractament d’aigua potable

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Water constitutes an essential resource for society. However, nowadays, millions of people still don’t have access to drinking water. This situation is getting worse due to the pollution of the hydric resources as well as the effects of climate change. For this reason, guaranteeing access to safe water must be a priority, and in this context, Drinking Water Treatment Plants (DWTPs) are very important. These facilities have the goal to ensure that water intended for human consumption accomplishes the sanitary standards throughout several treatment stages. Among these stages, we can find a pretreatment that applies ozone to water. In this stage, the application of ozone eliminates microorganisms, organic ions and organic pollutants because ozone is a potent oxidant agent. The aim of this stage is to reduce the organic matter load that will go to the following stages in order to improve the efficiency of future stages. This study investigates how the application of ozone affects the organic matter present in water and the efficiency of three different ozone doses applied to the entrance water of the DWTP of Montfulla: 0 mg O3 /mg DOC, 0,25 mg O3 /mg DOC and 0,5 mg O3 /mg DOC. Later, these treated samples are exposed to the conventional stages of the Montfullà DWTP which correspond to a coagulation/flocculation, adsorption by activated carbon and chlorination. Once these stages are completed, an exhaustive characterization of the organic matter found in water has been carried out by observing different parameters. Among them, to determine the organic matter the fluorescence and the absorbance at a wavelength of 254 nm were evaluated. Also, the trihalomethane (THM) formation potential of each stage was studied after chlorination, and the different fluorescent fractions in the water were also studied using PARAFAC. The results obtained show that the application of ozone significantly improves the elimination of organic matter as well as the reduction of trihalomethane (THM) formation potential, especially at high doses. This study can serve as a basis for future studies aimed at improving the water quality as well as reducing operational costs of DWTPs

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