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Removal of microplastics from water
Skalníková, Andrea ; Pivokonský, Martin (advisor) ; Čermáková, Lenka (referee)
The aim of this diploma thesis is to investigate the removability of microplastsic particles with different shapes (fragments, sphers, fibers) by standard water treatment process, such as coagulation, filtration and sedimentation. For the experimental purpose in this study, polyvinyl chloride with a size ≤ 50 μm and a density of 1.38 g/cm3 , was used as a representative of microplastics. The coagulation has been provided by ferric sulphate in pH range 5, 6, 7 and 8 and at a diferent dose of coagulant 20, 40, and 60 mg/l. The study results has shown, that the coagulation efficiency of polyvinyl chloride particles were affected by pH. The optimal value of pH has been 7 at the coagulant dose of 20, 40 and 60 mg/l. The presence of polyvinyl chloride shown a positive effect on coagulation. It has been reflected in a reduction of the residuals of iron concentration after coagulation, at pH 5-7. Solution with polyvinyl chloride contained 1,2 mg/l dissolved organic carbon. After fitlration the concentration decreased up to 70 % at pH 7 at dose of coagulant 40 and 60 mg/l. Experiments have shown that polyvinyl chloride particles are capable of faster sedimentation after coagulation. The flocs formed during coagulation interacted effectively with the polyvinyl chloride particles and facilitate their removal...
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Characterisation and elimination of compounds difficult to remove during water treatment
Čermáková, Lenka ; Pivokonský, Martin (advisor) ; Sochorová, Helena (referee) ; Brányik, Tomáš (referee)
The Ph.D. thesis deals with the characterization of algal organic matter (AOM), which is difficult to remove in water treatment, and on the basis of AOM character, various methods for its elimination, e.g. coagulation, oxidation with subsequent coagulation and adsorption onto activated carbon are assesed. Special emphasis is placed on identifying the optimal conditions of the processes and on describing the mechanisms and interactions involved. In terms of anthropogenic micropollutants, the thesis deals with the highly topical issue of the occurrence of microplastics in water. It was found that the removal efficiency of the individual AOM components varies substantially depending on the elimination method used. The identified optimum conditions of individual methods and especially the mechanisms that apply to the removal of target substances varied widely. The non-proteinaceous fraction of AOM was removed with very low efficiency (max. 25%) by conventional coagulation even under optimized conditions (pH 6.6- 7.5 for aluminium sulfate as the coagulating agent and pH 7.5-9.0 for polyaluminium chloride) and it was given by the high content of low molecular weight (LMW) substances that are difficult to coagulate. The dominant coagulation mechanism was adsorption onto aluminium hydroxide precipitates....
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Optimization of the coagulation process at the Březová water treatment plant
Pivokonský, Martin ; Čermáková, Lenka ; Prokopová, Michaela ; Pivokonská, Lenka
The presented report deals with the description of raw water quality focusing mainly on the nature of the contained organic substances, then a comprehensive evaluation of the operational efficiency of existing aggregation and laboratory optimization of coagulation operating parameters - especially the dose of coagulant and reaction pH. Coagulation in combination with sedimentation and sand filtration must be understood not only as the first stage of water treatment before ultrafiltration, but also as protection of the membranes themselves from their clogging, especially by macromolecular organic substances. From this point of view, it is necessary to operate coagulation with subsequent separation of aggregates with the maximum possible efficiency.
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Microplastics in Drinking Water
Čermáková, Lenka ; Novotná, Kateřina ; Peer, Petra ; Janda, V. ; Pivokonský, Martin
The research was focused on microplastics occurring in water sources and in drinking water. Recently, the topic of microplastics in water is very up to date. However, most of the studies are focused on quantification of microplastics in sea water, sediments or surface waters, which are not a source of raw water for drinking water treatment, and at the same time the most of studies deal with the analysis of particles in the size range of 0.3 - 5 mm. The subject of the present study was to quantify microplastics from 0.2 μm in raw and treated water from three unnamed water treatment plants in the Czech Republic and to determine their size distribution, shape and material composition. It has been found that the number of microplastics ranged from 1414-7006 L-1 particles in raw water and 305-921 L-1 particles in treated water. Microplastics smaller than 10 μm were the most plentiful in both raw and treated water samples. Fragments clearly prevailed at two of the water treatment plants and fibres together with fragments predominated at one case.
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Experimental Report, Period 9-12/2017, Project: Electrocoagulation Unit for Microalgal Biomass Separation.
Brányiková, Irena ; Vojtěchovský, R. ; Čermáková, Lenka
Production of microalgae in the world is increasing every year, but their use in food, cosmetics, feed and biofuel production is still limited by the high production price and high energy input. The substantial part of the energy costs lies in the separation of algal biomass from the medium, which is most often performed on plate centrifuges. The harvest concentration of algal suspensions in most cultivation systems ranges between just 1-5 g/L. Therefore, to obtain 1 kg of dry biomass, it is necessary to remove 200 to 1000 liters of water (by centrifuging and then drying). This amount of water and thus the energy input can be reduced via flocculation added as a pre-step prior to centrifugation. Electrofloculation is type of floculation, where the flocculant is directly formed by dissolving the electrodes. Suitable electrode material and parameter set enable obtaining of biomass, which is not contaminated by chemical flocculants and meets requirements for food stuff. The main objective of this project is to develop a continuous electroflocculation device suitable for these purposes.\n
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Experimental Plan for the Project: Electrocoagulation Unit for Microalgal Biomass Separation.
Brányiková, Irena ; Vojtěchovský, R. ; Čermáková, Lenka
Electrofloculation (electrocoagulation) of microalgae is a highly complex process involving a number of very complex transport, electrochemical, hydrodynamic and surface phenomena. The description of this process at the level of single mechanisms involved is too complicated and experimentally demanding, fortunately it is not absolutely necessary for the practical application. The electrofloculation was therefore approached by an engineering method that identified the criteria (range) of the desired variables and the main factors that affect them. For these factors, partial factorial experimental plans were designed.
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