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Abstract

The objective of the paper is to use life cycle assessment to compare environmental impact of different technologies used in the process of water disinfection. Two scenarios are developed for water disinfection life cycle at ZUW Raba water treatment plant: (1) historical, in which gaseous chlorine is used as a disinfectant and (2) actual, in which UV radiation and electrolytically generated sodium hypochlorite are used for that purpose. Primary data is supplemented with ecoinvent 3 database records. Environmental impact is assessed by IMPACT2002+ method and its midpoint and endpoint indicators that are calculated with the use of SimaPro 8.4 software. The focus of the assessment is on selected life cycle phases: disinfection process itself and the water distribution process that follows. The assessment uses the data on flows and emissions streams as observed in the Raba plant. As the results of primal analysis show, a change of disinfectant results in quantitative changes in THMs and free chlorine in water supplied to the water supply network. The results of analysis confirm the higher potential of THMs formation and higher environmental impact of the combined method of UV/NaClO disinfection in distribution phase and in whole life cycle, mainly due to the increase of human toxicity factors. However, during the disinfection phase, gaseous chlorine use is more harmful for environment. But the final conclusion states that water quality indicators are not significant in the context of LCA, while both disinfection and distribution phases are concerned.
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Abstract

Production of sanitary safe water of high quality with membrane technology is an alternative for conventional disinfection methods, as UF and MF membranes are found to be an effective barrier for pathogenic protozoa cysts, bacteria, and partially, viruses. The application of membranes in water treatment enables the reduction of chlorine consumption during final disinfection, what is especially recommended for long water distribution systems, in which microbiological quality of water needs to be effectively maintained. Membrane filtration, especially ultrafiltration and microfiltration, can be applied to enhance and improve disinfection of water and biologically treated wastewater, as ultrafiltration act as a barrier for viruses, bacteria and protozoa, but microfiltration does not remove viruses. As an example of direct application of UF/MF to wastewater treatment, including disinfection, membrane bioreactors can be mentioned. Additionally, membrane techniques are used in removal of disinfection byproducts from water. For this purpose, high pressure driven membrane processes, i.e. reverse osmosis and nanofiltration are mainly applied, however, in the case of inorganic DBPs, electrodialysis or Donnan dialysis can also be considered.
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Abstract

The article presents the results of the research on the water samples taken from the Krakow water distribution system and their pollution by haloacetic acids: monochloroacetic acid, monobromoacetic acid, dichloroacetic acid, trichloroacetic acid, bromochloroacetic acid and dibromoacetic acid. The water samples were taken from the extremities of the distribution systems (Raba and Bielany) in the city of Krakow. Both analyzed plants use the chlorination as the water treatment process, however, water for Raba and Bielany comes from different surface waters and differs in quality and organic matter concentration. These plants also apply different water treatment processes and their distribution systems have a different size. The objective of this study was to measure the haloacetic acids levels in these two water distribution systems, asses the correlation between the total trihalomethanes and the sum of six haloacetic acids, determine if trihalomethanes can be a good indicator to predict haloacetic acids concentration in water distribution systems.
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Abstract

The paper presents the results of experiments on the influence of the organic matter’s characteristics on the formation potential of water chlorination by-products – representatives of the following groups: trihalomethanes, haloacetonitriles, haloketones, chloral hydrate and chloropicrin. The products of water fractionation (the hydrophobic and hydrophilic acids, hydrophobic and hydrophilic bases, and hydrophobic and hydrophilic neutral fractions) were chlorinated with sodium hypochlorite. Its dose was adjusted to obtain a residual free chlorine concentration between 3 and 5 mg/dm3 after 24 h. After this time, the water chlorination by-products were analyzed with gas chromatography. The results’ analysis has defined the fractions, which have the highest potential to form particular groups of volatile organic water chlorination by-products.
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