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Application of Specific UV Absorbance (SUVA) for natural organic matter characterization
Vítková, Tereza ; Pivokonský, Martin (advisor) ; Načeradská, Jana (referee)
This bachelor thesis focuses on the characterization of parameter of specific UV absorbance (SUVA), which has currently been used during water treatment to estimate the potential of natural organic matter (NOM) to form by-products of water disinfection. SUVA is defined as the ratio of absorbance at 254 nm and the values of the concentration of dissolved carbon (DOC). First, SUVA was used as a surrogate parameter instead of more complex measurements to assess the potential formation of trihalomethanes (THMs) (Edzwald et al., 1985). Currently ability of the parameter SUVA to predict the formation of individual classes of DBPs (Disinfection By-Products) on hygiene of drinking water has been studied most. Most of the studies examine in particular the formation of THMs and HAAs (Haloacetic Acids) which are strictly regulated because of their harmful effect for the environment and human health. Its questionless advantage is a quick and easy setting directly in the water treatment plants. However, the existing studies provide quite contradictory conclusions regarding its practical benefits to predict how the water reacts with disinfectant and forms DBPs during the treatment. Based on the evaluation of the available literature SUVA seems to be more suitable for humic nature water which show high value SUVA...
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Per- and polyfluoroalkyl substances in drinking water
Skalický, Daniel ; Načeradská, Jana (advisor) ; Semerád, Jaroslav (referee)
Per- and polyfluoroalkyl substances are synthetic organic compounds which, due to their physicochemical properties, have a high application in many consumer products such as aqueous film forming foams or detergents. In the context with their worldwide use and their long persistance in the environment their concentrations also have been detected in remote areas without direct surrounding sources including plants, animals and humans. PFAS concentrations in surface water and groundwater range from tens of ng/l, in the case of strong point sources to hundreds of ng/l. In the seas and oceans, PFAS concentrations are most often in the tens of pg/l due to dilution. The 2 most frequently discussed substances, perfluorooctanoic acid and perfluorooctanesulfonate, have been classified as a persistent organic pollutants because of their negative effects on human health. However, based on toxicological studies, many other substances in this group also appear to be toxic so some countries have set recommended limits for their reduction. Drinking waters have concentrations in the order of units up to tens of ng/l and therefore generally do not exceed the recommended values. However, in the area of point source of pollution, PFASs values are strongly elevated and therefore their identification and subsequent...
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Haloacetic acids in drinking water
Poslušná, Markéta ; Načeradská, Jana (advisor) ; Barešová, Magdalena (referee)
Chlorination byproduct occur during water disinfection. These by-product are formed by the reactions between disinfectants and natural organic matter. High concentration od natural organic matter require higher doses of oxidizing agent, which increases the formation of chlorination byproduct. Chlorination byproduct pose health risk so they must be eliminated. This work researches focuses on the occurence of chlorination byproduct in several countries and evaluates the suitability of limits concentrations. The literary research has shown that there are currently not many studies about monitoring the occurence of chlorination byproduct. If these studies exist, they are often old and therefore i tis not possible to rationally assess the quality of drinking water in term of the occurrence of chlorination byproduct. Trichloracetic acid, dichloracetit acid and dibromacetic acid are mainly important from the health point of view. The are identifield as possible carcinogens. Higher concentrations of dichloracetic acid and trichloracetic acid were observed in most studies. The result of the studies show that the highest concentration of haloacetic acid were recorded in the cities of Cherepovets (Rusia), Athens (Greece), Warsaw (Poland) and Findland. Concentrations of haloacetic acid did not exceed the limit...
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Coagulation of organic matter produced by phytoplankton
Načeradská, Jana
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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Oxidation of compounds produced by cyanobacteria Microcystis aeruginosa and its impact on water treatment by coagulation
Štědrá, Karolína ; Načeradská, Jana (advisor) ; Kopecká, Ivana (referee)
Due to eutrophication of aquatic environment, massive growth of algae and cyanobacteria occurs and the seasonal algal bloom is formed. Drinking water treatment plants have to deal with the increased amount of cells as well as organic compounds produced by algae and cyanobacteria (so-called AOM). Moreover, the presence of AOM causes a reduction in the efficiency of coagulation, which is an essential process in drinking water treatment. To increase coagulation efficiency, supportive methods, such as ozone oxidation, are added usually prior to coagulation. While many studies focused on the ozonation of algal and cyanobacterial cells, little is known about the effect of ozonation on AOM. This diploma thesis focused on the evaluation of the effect of ozonation in combination with coagulation on the removal of cellular organic compounds (COM) produced by cyanobacteria Microcystis aeruginosa. The effect of ozonation before or after coagulation on COM removal was investigated. The degradation of microcystins, which are naturally contained in the COM sample, was also monitored. Various ozone doses (1 - 10 mg/L) were tested at three pH values - 5, 7 and 9. Two coagulants were utilized - aluminium sulphate and ferric sulphate. Ozonation removed COM negligibly. However, eliminated microcystins, the degradation...
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Jar Test Methodology for Water Treatment Optimization
Pivokonský, Martin ; Pivokonská, Lenka ; Vašatová, Petra ; Načeradská, Jana
The methodology is intended for water treatment plant (WTP) operators and serves as a basic guideline for an optimization of the coagulation process in water treatment. It describes the jar test procedure, which allows the determination of the optimum operating conditions of coagulation, i.e., type and dose of the coagulant and coagulation pH value, needed for reaching the highest treatment efficiency. The publication further contains a supplementary part with tables for conversion of molar to mass concentration (and vice versa) of coagulants, instructions for diluting coagulants and reagents for pH adjustment and examples of jar test data recording, processing and evaluation.
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The impact of oxidation processes on AOM coagulation
Titov, Ivan ; Načeradská, Jana (advisor) ; Novotná, Kateřina (referee)
Due to anthropogenic impact, surface water sources are subject to intensive growth of phytoplankton communities. This poses a problem for water treatment, not only because water contains a large number of algae cells, but also because of the high concentrations of algal organic matter (AOM). These substances are characterized by low removability during the conventional water treatment process by coagulation, and therefore the increase in AOM removability is currently being researched. Oxidation pretreatment before coagulation is one of the methods that increase the effectiveness of algae and its excreted matter's removability. This work researches the influence of oxidation treatment on AOM removability by coagulation, and on treated water quality. The literary research has shown that pre-oxidation is rather ambiguous in terms of AOM coagulation. From one point of view, with the correct calibration of operation conditions, a right choice of oxidation process and the optimum oxidant dosage it is possible to achieve an effectiveness increase of partial AOM removal (e.g. cyanotoxins, taste and odour compounds and low molecular weight compounds with the help of mineralization). Pre-oxidation, however, can impair AOM coagulation by transforming high molecular weight compounds into low molecular weight...
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Coagulation of organic matter produced by phytoplankton
Načeradská, Jana
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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Coagulation of different kinds of algal organic matter
Novotná, Kateřina ; Načeradská, Jana ; Barešová, Magdalena ; Janda, V. ; Pivokonský, Martin
This study focused on coagulation of different algal organic matter (AOM) fractions, especially on its non-proteinaceous fraction. It was derived from cellular organic matter of Chlorella vulgaris, a freshwater algae. Two different Al-based coagulants were employed, i.e. alum and pre-hydrolyzed polyaluminim chloride (PACl). The highest coagulation efficiency was obtained at pH around neutral (pH 7.1-7.5 for alum and pH 7.6-8.0 for PACl) at relatively high dosages of coagulant (8 and 10 mg·L-1 as Al for alum and PACl, resp.). However, the maximum removal reached under the optimized conditions was only approximately 20%. The coagulation behaviour and efficiency of non-proteinaceous matter greatly differ from AOM peptide-proteins, which is discussed in the study.
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Are cyanobacteria capable of enhancing drinking water treatment? Sci-fi or reality?
Barešová, Magdalena ; Načeradská, Jana ; Novotná, Kateřina ; Pivokonská, Lenka ; Pivokonský, Martin
Drinking water treatment struggles with cyanobacteria and algae mainly on a seasonal basis especially when they decay and release amounts of cellular organic matter (COM). As COM is not only difficult to be removed but it also impacts the removability of other impurities, this paper aims to evaluate the effect of COM derived from two common cyanobacterial species– Microcystis aeruginosa and Merismopedia tenuissima on coagulation of other naturally occurring particles and molecules present in surface waters: kaolin suspension, humin substances and cells of M. tenuissima. Our findings show that higher COM concentrations do not have to disrupt coagulation. When COM interacts with other impurities, it can even lower coagulant doses and increase both turbidity and humic matter removal efficiencies.
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