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Colloids in landfill waters and leachates
Janko, Jiří ; Ettler, Vojtěch (advisor) ; Matura, Marek (referee)
Contamination of surface water or groundwater by metals and/or metalloids, originating from landfill leachates is environmental concern in the vicinity of landfills designed for disposal for municipal solid waste (MSW). It is known that many organic compounds and metals/metalloids can be associated with colloids of the size 1 nm-1 μm. This relationship is mainly caused by the total surface area of colloids and consequently their binding capacity for contaminants occuring in the aqueous environment. In order to identify these associations in landfill leachates a cascade frontal filtration/ultra filtration is often adopted. Colloids obtained by this size-fractionation can be further studied by scanning electron microscope (SEM) or transmission electron microscope (TEM) coupled to energy dispersive spectroscopy (EDS). Typical example is a Vejen landfill in Denmark, which has been extensively studied, where leachate samples exhibited significant proportion of total metal content to be associated to colloids - Cd: 38-45%, Ni: 27-56%, Zn: 24-45%, Cu: 86-95% a Pb: 96-99%. Whereas Cd, Zn and Ni were mostly associated with smaller colloids (1-10 nm), other metals like Pb and Cu were bound to colloids of the size > 10 nm. A number of investigations from other landfill sites indicated similar results. Powered by TCPDF...
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Binding of trace elements to colloids in MSW landfill leachates
Matura, Marek ; Ettler, Vojtěch (advisor) ; Pitter, Pavel (referee) ; Faimon, Jiří (referee)
1 SUMMARY The association of trace elements with colloids in leachates from closed and active municipal solid waste (MSW) was studied using the cascade filtration/ultrafiltration method. A study was carried out after long-term monitoring of seasonal variations of the leachate quality. Both landfills are situated in the vicinity of Prague and the closed landfill site represents a serious environmental risk for part of this city. In the first step, the evaluation of the long-term seasonal changes in the main and trace element contents in leachate from the closed landfill was performed and supplemented by investigation of precipitation/dissolution processes in the solid phases. It was shown that the quality of the leachate is strongly influenced by rain events, which are responsible for the dissolution of calcite and Fe oxides in the landfill body. This process leads to the release of Cu, Zn and Cd bound to these solid phases and to an increase in their concentrations in the leachate. The contents of the other element are significantly decreased by simple dilution. Therefore, the mobility of all the studied elements increases substantially during rain events. Monitoring of the seasonal variation in the leachate quality enabled us to determine the appropriate conditions for isolated sampling for studying the...
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Selection of merchandising and gifts supplier in an international company
Matura, Marek ; Fotr, Jiří (advisor) ; Špaček, Miroslav (referee)
The aim of this thesis is analysis and resolution of the decision-making problem "selection of merchandising and gifts supplier in an international company" using multi-criteria decision process while respecting risk. The goal of this thesis is to select a suitable supplier and offer recommendation to company's management for solving similar decision processes. The theoretical part of the thesis describes the knowledge base of methods and procedures of decision analysis that are later applied in the practical part of the thesis on the specific project with aim to optimize the decision-making process and identify the best variant. The conclusion of the thesis provides recommendations for solving similar problem in the future.
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