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Membrane technologies for agricultural wastewater treatment
Uhlířová, Marcela ; Touš, Michal (referee) ; Vondra, Marek (advisor)
This thesis deals with an agricultural wastewater treatment (liquid digestate) by membrane technology. There is a fundamental description of characteristics of membrane technology with regard to application of agricultural wastewater treatment in this thesis. Experimental device for treatment of liquid digestate is designed and it consists of three steps – microfiltration, ultrafiltration and reverse osmosis. The first step consists of four filters with different pore sizes (80, 25, 10 and 5 µm). The second step is ultrafiltration and the third and key step is reverse osmosis. In the final step monovalent ions such as NH4+ are separated. Reverse osmosis consists of two stage system which results in higher recovery. Three experiments were carried out in order to verify the efficiency of separation dissolved solids.
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Phosphorus recovery from liquid digestate
Heger, Jan ; Procházková, Michaela (referee) ; Touš, Michal (advisor)
The focus of this thesis is the posibility of obtaining phosphorus from liquid digestate. The theoretical part of the thesis is focused on summarizing the current situation regarding phosphorus recovery. The research summarizes the essential information about the method of struvite precipitation, by which phoshphorus is obtained in the form of struvite, which can be further used as a fertilizer. Based on the process information, an experimental device was designed to obtain phosphorus in the form of struvite, corresponding to industry standards. It is a cylindrical vessel with a conical bottom, in which the liquid digestate with the chemicals is mixed with a stirrer. The functionality of the device was tested experimentally on the created device. The results of the experiment were analyzed by XPS method, which confirmed the formation of struvite. For future operation, modifications of the device and pre-treatment of the liquid digestate were proposed, which could improve the whole process and its results.
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Treatment of waste from biogas plants
Budín, Oto ; Frýba, Lukáš (referee) ; Vondra, Marek (advisor)
This bachelor thesis is focused on options of treatment of waste from biogas plants. The first part of this thesis describes biogas plants and its working. The main target of the thesis deals with waste from biogas plants – its creation, properties, composition and application. The thesis also includes an overview of legislative and environmental restrictions applying to the treatment of waste from biogas plants. The bachelor thesis also comprises an information about biogas plants Stanoviště.
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Optimization of Gasification Process of Biodegradable Wastes
Elbl, Patrik ; Milčák, Pavel (referee) ; Lisý, Martin (advisor)
The aim of the diploma thesis is to discuss the gasification of biodegradable waste. The theoretical part deals with gasification with focus on gasification phases, types of gasification reactors and pollutants contained in the generated gas, especially tar. Further, there is listed the characteristic of alternative biomass fuels, namely digestate and sludge waste. The practical part is devoted to gasification on a fluidized bed reactor with the aim to test the possibilities of gasification of these fuels, to determine their specifications and the influence of various gasification media. In the final part there are discussed the results of the collected gases and tar.
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Integration of a technology for digestate thickening in a biogas plant
Miklas, Václav ; Touš, Michal (referee) ; Vondra, Marek (advisor)
This diploma thesis is mainly focused on the digestate thickening in a biogas plant. First, overview of the biogas technology in the Czech Republic is presented. Furthermore, problems with waste heat utilization and processing of fermentation residues (digestate) are described in more detail. Based on the research, multi-stage flash (MSF) evaporation was chosen as the technology for the digestate thickening. The main part deals with the integration of the chosen technology into a biogas plant process. The programming language Python was used to simplify the given task. In the preliminary stage, a complex mathematical model of a biogas plant was created, focusing particularly on the mass and energy balances. Subsequently, a computational model of the MSF evaporator was programmed. A procedure for the integration was suggested using the sensitivity analyses. Additionally, the model of a biogas plant was extended with the MSF evaporator. The key outcome of the thesis is a technical-economic analysis in which the impact of digestate transport price and electricity feed-in tariff on payback period is investigated. The results suggest profitability of MSF evaporator for biogas plants without subsidized feed-in tariff. Contrastingly, installation of MSF evaporator in older biogas plants with subsidized feed-in tariff can be economically viable only in cases of significantly longer transport distances.
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Fermentation remainder treatment in a biogas plant
Budín, Oto ; Touš, Michal (referee) ; Vondra, Marek (advisor)
This diploma thesis deals with dewatering technologies of fermentation residues from biogas plants and aims to design an integration of selected technology into the biogas plant. Fermentation residues (or digestate), which are a by-product of anaerobic biomass fermentation in biogas plants, contain a certain amount of nutrients and are usually used as agricultural fertilizers. However, the high-water content in digestate and the associated low nutrient concentration increase the cost of its storage and transport. Dewatering of fermented material could help reduce these costs. The main part of this work included the design of an integration of the selected dewatering technology into the biogas plant – its placement in a process, an addition of necessary appliances, the influence on material and energy flows. In this case, the fermentation residues are processed in two phases. First, a separation of the solid and the liquid fraction by a screw press. The second step is to thicken the liquid digestate by evaporation in a multistage evaporator. Evaluation of the design of a dewatering technology, including its impact on the economy of the biogas plant, is also part of the diploma thesis.
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Energy use of digestate
Kaška, Zdeněk ; Štelcl, Otakar (referee) ; Baláš, Marek (advisor)
This bachelor thesis deals with the research of biomass in general, its types and processing. Nowadays, biomass appears to be an environmentally and financially acceptable substitute for fossil fuels due to increasingly stringent emissions standards. The second part deals with its particular type, digestate. It is investigated whether the fossil fuel can be replaced or how the energy production process could be changed.
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Control methods for wastewater pH
Picka, Marek ; Vondra, Marek (referee) ; Miklas, Václav (advisor)
The bachelor thesis initially deals with the process of wastewater treatment with a focus on measurement, pH control and related issues. The pH value is an important parameter in wastewater treatment, which influences physical, chemical and biological processes as well as digestate treatment processes. This paper focuses on the process of thickening of digestate from a biogas plant by evaporation, which is normally associated with the leakage of volatile ammonia into the distillate. In order to eliminate this phenomenon, four methods of pH reduction were compared, which leads to the conversion of nitrogen from the volatile undesirable form 3 to the desirable form + 4 or 3 , which does not evaporate into the distillate during the evaporation process but remains in the concentrate, thus yielding a high quality fertilizer. Of the 4 methods discussed, the nitrification method appears to be the best in terms of the quality of the fertilizer output, but its disadvantage is the long retention time. From the point of view of flue gas utilization, lowering the pH by bubbling 2 and acidification with acid is a suitable method. For cases where speed and low acquisition costs are important, pH reduction with acid is preferable, unless high operating costs are a problem. In order to assess the correct method of pH reduction for a particular biogas plant, a techno-economic evaluation and consideration of other operational constraints is required and will be the subject of future work.
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