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Water treatment and disinfection in outdoor conditions
Hrušková, Barbora ; Načeradská, Jana (advisor) ; Petříček, Radim (referee)
Travel to countries with inadequate sanitation facilities or to the wild involves the risk of contracting pathogenic organisms. There are several options for providing hygienic drinking water in field conditions. The main objective of this paper is to present these options to the reader, to evaluate the advantages and disadvantages of different types of water treatment and disinfection in the field, and to assess the health risk of consuming water treated in field conditions. For while there are a large number of studies on water treatment in water treatment plants, there are few studies on water treatment under field conditions, and in particular the generation of disinfection by-products (DBPs) during field water disinfection. One method to treat water in the field is the use of filtration. Filters can remove suspended solids and bacteria from water due to membranes with pore sizes of about 0.2 μm. The advantage of filters is that they do not encourage the formation of DBPs. On the other hand, 0.2 μm pore sizes may not stop all pathogens. Disinfection with UV light has been shown to be effective, but in turbid water the effectiveness decreases. It is recommended to stir the water with a UV lamp to improve the disinfection results. UV does not produce DBPs, which is an undeniable advantage of this...
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Pharmaceuticals in drinking water and their removal
Benešová, Tereza ; Načeradská, Jana (advisor) ; Vašatová, Petra (referee)
This bachelor thesis focuses on the presence of pharmaceuticals in drinking water and their effective removal. The first part of the thesis describes in detail the pathway by which pharmaceuticals enter surface waters that can serve as a source for drinking water. In the Czech Republic, these are sources of drinking water for Prague and its surroundings. Because filtration, flocculation/coagulation is not efficient enough, it removes only 20% of the drugs such as ibalgin, carbamazepine, naproxen and diclofenac. Therefore, it is necessary to supplement drinking water treatment plants with other processes such as adsorption on activated carbon, which removes up to 98%, ozonation and advanced oxidation processes, with an efficiency of up to 99%, and UV/chlorine removes up to 80% of pharmaceuticals. I found that monitoring of pharmaceuticals in drinking water is not systematic and there is a lack of setting of possible limits. The Želivka water treatment plant was found to carry out tests for pharmaceuticals only once a year, which I consider insufficient. I think that it is advisable to carry out more frequent analyses of medicines in drinking water in order to have a continuous overview of the situation. In addition, there are no long-term studies examining the effect of medicines in drinking water...
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Brominated and iodinated disinfection by-products
Bednář, Jiří ; Načeradská, Jana (advisor) ; Kopecká, Ivana (referee)
The reaction of a disinfectant with natural organic matter in the presence of bromides and iodides in raw water intended as a source of drinking water produces brominated (Br-DBPs) and iodinated disinfection by-products (I-DBPs) of water. These tend to be more cytotoxic and genotoxic than their chlorinated analogues. However, little information is available on these products compared to chlorinated ones. Therefore, the aim of this work was to provide an overview of natural and anthropogenic sources of bromine and iodine containing substances, to determine their influence on the formation of brominated and iodinated disinfection by-products, and to compare their cytotoxicity and genotoxicity with chlorinated products. Increasing seawater intrusion into the groundwater drinking water source was found to increase the concentrations of Br-DBPs and I-DBPs by up to thousands of percent. A number of substances can be released from water pipe material depending on the material. These include, for example, tenorite and copper cation released from copper piping, iron cation released from cast iron and steel piping, and bromides and dissolved organic carbon (DOC) released from plastic piping. All of these corrosion products contribute to increasing concentrations of DBPs in the distribution network. Both seawater and...
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Toxic products of cyanobacteria with the focus on endotoxins
Eršilová, Kateřina ; Načeradská, Jana (advisor) ; Semerád, Jaroslav (referee)
Cyanotoxins are toxic products of cyanobacteria that cause problems (e.g. humans can experience unrecognised health effects), especially when they are overgrown. These cyanotoxins include the group of endotoxins, which includes lipopolysaccharides. Based on a literature search, it was found that the structure of these compounds consists of three chemical parts, Lipid A, a central oligosaccharide and O-Antigen. The structure is not the same for all cyanobacterial species and shows considerable variation. As far as the toxicity of lipopolysaccharides is concerned, it appears to be higher in Gram-negative bacteria than in cyanobacteria. The work in section 4.1 on toxicity states that microcystins do not play a major role in toxicity to Daphnia and that other substances from cyanobacteria will be toxic, while lipopolysaccharides are not excreted. In contrast, Chapter 6 states that lipopolysaccharides from Microcystis are not toxic to Daphnia and that other substances will be behind the toxicity. The thesis further considers that a large number of toxic substances coexist in water blooms, thus synergistic effects are at work in water blooms, hence the toxicity of cultures cultivated in laboratories is lower compared to the toxicity of natural cyanobacterial blooms. Water bloom contain many different...
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Combination of different drinking water disinfection processes and their impact on the formation of disinfection by-products
Česká, Pavlína ; Načeradská, Jana (advisor) ; Fialová, Kateřina (referee)
Combining disinfection processes with chlorination can alter the formation and resulting spectrum of Disinfection By-Products (DBPs) in drinking water. While considerable attention has been given to DBPs formed during chlorination, DBPs formed during the application of multiple disinfection processes are a significantly less explored group. This study focuses on three most common disinfection combinations: chlorination-UV, UV-secondary chlorination, and ozonation-secondary chlorination. After chlorination, trihalomethanes (THMs) and haloacetic acids (HAAs) are the most commonly found DBPs in water. The resulting formation of DBPs is influenced by many factors. UV radiation at typical disinfection doses (40-186 mJ.cm-2 ) does not affect the formation of these two groups of compounds after treatment with UV radiation and secondary chlorination. During the advanced oxidation process (AOP) of chlorination-UV, generally more DBPs are formed than during chlorination alone. However, this can be partially minimized by adjusting the appropriate wavelength and pH of the treated water. For waters containing nitrogenous compounds or bromide, combining chlorination with UV radiation and chlorination with ozonation leads to higher formation of hazardous nitrogenous and brominated DBPs compared to chlorination...
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Disinfection by-products originating from pesticides
Plachá, Markéta ; Načeradská, Jana (advisor) ; Kopecká, Ivana (referee)
An important step in the treatment of drinking water is disinfection, which serves to remove pathogenic substances. During this process, disinfection by-products can be formed, which are mainly produced from organic natural substances reacting with the disinfectant. However, treated water may also contain anthropogenic substances, such as pesticides, whose disinfection by-products are the subject of this work. From the accessible data of the studies carried out so far, a basic summary of their creation was created, and characteristic properties that are essential for the evaluation of adverse effects on human health and the environment. From the field of organophosphorus pesticides, it was found that pesticides containing a phosphorothioate part can be easily oxidized by chlorine to the corresponding oxone derivative, while organophosphorus pesticides with a phosphate part are very stable in the presence of chlorine. The resulting oxon forms can be more effective inhibitors of acetylcholinesterase than their parent compounds and at the same time be stable enough (more than 24 h) to reach the consumer, on whom they can, however, have a negative effect. At the same time, disinfection by- products from pesticides can be more toxic than the original compounds. These include chloroxon, diazoxon and...
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Household drinking water filters
Horáková, Gabriela ; Načeradská, Jana (advisor) ; Fialová, Kateřina (referee)
The thesis summarizes the current knowledge about the use of domestic point-of-use water filters and evaluates their advantages and disadvantages. The main advantage of using these devices is the removal of unwanted substances that can be found in drinking water. These substances can be, for example, disinfection by-products and micropollutants, such as pharmaceutical or pesticide residues. Especially for well water users, filters can be a a good option for arsenic and nitrates removal. Filters are also able to improve the organoleptic properties of drinking water. Among the undesirable effects of using home filters is a change in the microbiological quality of the filtered water, caused by regrowth of bacteria on the filter. An increase in the concentration of opportunistic pathogenic bacteria in filtered water can be problematic, this can pose a risk especially to immunocompromised persons. Another undesirable effect can be the unintentional removal of necessary minerals, especially when using devices operating on the principle of reverse osmosis. The concentrations of silver that can be released from bacteriostatically treated activated carbon are so low that based on current knowledge, they should not pose a health risk. Based on the collected information, several recommendations are proposed...
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Comparison of chemical oxygen demand and total organic carbon for the determination of organic carbon content in water
Tobolková, Eva ; Načeradská, Jana (advisor) ; Novotná, Kateřina (referee)
Chemical oxygen demand (COD) and total organic carbon (TOC) are determinations that are used to summarize the organic pollution of waters. However, these determinations do not provide the same information about the content of organic substances in waters. COD is an oxidation method and different substances react differently to this determination. TOC is more accurate as an indicator of organic pollution. Therefore, their ratio will be different for waters with different compositions. This work focuses on evaluating the advantages and disadvantages of determining COD and TOC and comparing their ratios in waters with different compositions. The goal of the work was also to determine whether it is appropriate to introduce coefficients for converting COD and TOC for different types of water. Based on the literature search, it was found that the determination of TOC provides more accurate information on the content of organic pollution in all types of water. The determination of COD by the dichromate method is important for wastewater, mainly due to the estimation of the proportion of degradable pollution. The COD/TOC ratio for municipal waters is relatively stable due to their similar composition, and the determination of the conversion coefficient is possible. This does not apply to industrial...
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Disinfection by-products in swimming pools and their effect on human health
Winterová, Sofie ; Načeradská, Jana (advisor) ; Barešová, Magdalena (referee)
Disinfection of swimming pool water is necessary for reducing the risk of disease transmission. Disinfection by-products form when chlorine reacts with organic matter contained in water. More than six hundred disinfection by-products have been found in swimming pools. Trihalomethanes, haloacetic acids, chloramines, halonitromethanes, haloacetonitriles and nitrosamines are among the most frequently occurring. Disinfection by-products may be toxic. The volatility of some of them causes their occurrence in the surrounding air and poses a risk not only for swimmers, but also for people in the vicinity who are not in direct contact with the water. DBPs enter human body by inhalation, absorption through the skin and ingestion. They have been linked to health problems such as skin and eye irritation, bladder cancer and respiratory diseases. Preventing their occurrence is not an easy task; a number of factors play a role in their genesis (the amount of organic matter, type and the amount of disinfection, the quality of source water, temperature, pH) and not all principles of their formation have been fully clarified yet. Further research on DBPs and their sufficient regulation are important steps to maintain chemical safety in swimming pools. Key words: disinfection by-products, swimming pool,...
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Coagulation of organic matter produced by phytoplankton
Načeradská, Jana ; Pivokonský, Martin (advisor) ; Benešová, Libuše (referee) ; Janda, Václav (referee)
This dissertation thesis focuses on the removability of algal organic matter (AOM) by coagulation during water treatment and also on the influence of AOM on the coagulation of other substances present in source water. Special emphasis is put on the description of coagulation mechanisms. The effectiveness of AOM removal by coagulation was investigated by coagulation tests performed with optimized doses of coagulants (aluminium or ferric sulphate) under different pH values. Peptides and proteins contained in cellular organic matter of cyanobacterium Microcystis aeruginosa were used in the experiments since they have been previously reported to disturb the coagulation process. Moreover, peptides and proteins underwent coagulation experiments together with kaolin particles, representing clay particles in turbid waters, in both the presence and absence of coagulants to investigate the effect of AOM on the coagulation of turbid waters. To enable the description of coagulation mechanisms, AOM were characterised in terms of charge, functional groups, molecular weight and ability to form dissolved complexes with coagulant metals. The experimental results demonstrated that the removability of peptides and proteins is greatly dependent on pH value and on the properties of the involved particles or molecules....
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