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Dependence of Sludge Dewatering efficiency on amount of flocculant
Volejník, Tomáš ; Medek, Jaroslav (referee) ; Boráň, Jaroslav (advisor)
The target of the first part of this diploma thesis is focused on the problems relating to the sludge production from the wastewater treatment plant and subsequent sludge treatment. Wastewater treatment plant and individual processes from the sludge management are described. The process of the sludge dewatering is described more extensively. Various methods of the dewatering and materials balance are described, too. The second part of this thesis is based on the experiment which took place on wastewater treatment plant Tetčice. The influence of the polymeric organic flocculant dosing on the sludge dewatering was monitored by this experiment. Dependence of the sludge dry matter and filtrate suspended solids content on the specific amount of flocculant was evaluated from experiment’s outputs. Using materials balance and outputs of the experiment, economical balance was made. It made possible to choose the most economic and technologically optimal way of the sludge dewatering on wastewater treatment plant Tetčice.
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Nutrients recovery by processing liquid digestate
Štylárková, Petra ; Vondra, Marek (referee) ; Touš, Michal (advisor)
Biogas plants produce a large amount of digestate or liquid digestate annually, which can be further processed to obtain nutrients. This method is not widespread due to high investment costs. In this paper, technologies for nutrient recovery from liquid digestate as well as a techno-economic model are presented. This model was developed using information from literature and calculations in a process simulator. It is able to calculate the overall balance of the system from the input parameters and to tentatively assess the economic evaluation. The use of the model was demonstrated with a case study of a specific biogas plant. The analysis of the effects of the price parameters showed, among other things, that for the biogas plant in question the sensitivity of the return to a lower price of ammonium sulphate (product) is high, while in the case of struvite (product) even at its low price there is no such sensitivity.
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Treatment of thickened sludge from industrial wastewater
Peťovský, Patrik ; Procházková, Michaela (referee) ; Vondra, Marek (advisor)
The aim of the thesis is to present the problem of industrial sludge treatment and to identify and implement in laboratory conditions a suitable technology for the treatment of a specific industrial sludge, which is already partially thickened fermentation residues from the operation of biogas plants (BPS). Based on the research developed on available technologies for the treatment of waste sludge, the mixed evaporator was selected as a suitable technology. The advantage is the possibility of using the low potential heat from BPS CHP units under reduced pressure, which is often thwarted. The agitator in the evaporator ensures homogenization while increasing densification. The use of the technology results in a reduction in the volume of fermentation residues. The main part of the thesis deals with the design and implementation of a stirred evaporator for production. Experimental The plant was constructed on the premises of the LENP (Laboratory of Energy-Intensive Processes) at the Brno University of Technology. During operation, the functionality of the device and its applicability to several types of waste sludge were verified. The experimental results are mainly focused on the properties and behaviour of the fugate, or liquid fraction, of the fermentation residues. The fugate was concentrated from a raw state of 5.4 % dryness to a value of 20.9 % dryness, at which point it becomes a highly viscous and poorly flowing material. In an industrial plant where waste heat is wasted, a stirred evaporator may be a suitable device for sludge treatment or volume reduction. This leads to lower costs for storage, transport, and application as fertilizer to fields. With a suitable evaporator and agitator design, the evaporation principle can be used for less and more concentrated waste sludge. The resulting thickened product can then be fed to the finishing operations, allowing the distillate to be finished.
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Possibilities of utilization of nitrogen compounds from liquid suspensions generated in waste management
Vajdíková, Tereza ; Mergl, Václav (referee) ; Kalivoda, Josef (advisor)
This thesis deals with the removal of ammoniacal nitrogen from biogas plant waste to produce a new usable product. In the theoretical part of the thesis, attention is paid to waste management from the perspective of biogas plants, the problem of nitrogen, and its removal. The thesis contains, among other things, theoretical calculations that include distribution and precipitation curves. The practical part deals with the correctness of these curves, as well as the precipitation of ammonium ions to form ammonium magnesium phosphate and stripping. The practical part includes quantitative and qualitative analyses of the individual components involved in precipitation. Nitrogen removal was performed on the model and real samples.
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Liquid-vapor mass exchange in stripping processes
Liman, Martin ; Kalivoda, Josef (referee) ; Svěrák, Tomáš (advisor)
This diploma thesis deals with the solution of ammonia separation from waste raw materials of agricultural production. It focuses on determining the efficiency of desorption from an experimental stripping device depending on the measurement temperature. Ammonia water solutions and liquid digestate samples from technical practice were used to verify the functionality of the equipment. Increasing separation efficiency with increasing temperature has been demonstrated. The device was gradually improved during the measurement for a better profitability of the separation process. The results of the experiments are discussed concerning the theoretical assumptions and compared with other methods of ammonia separation.
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Assessment of evaporator integration into biogas plant
Peťovský, Patrik ; Touš, Michal (referee) ; Máša, Vítězslav (advisor)
The main waste output of the biogas plant is digested which is used as fertilizer. It can be further process. Digestate cannot be discharged freely into surface waters. This problem is associated with high transportation costs and higher costs of storage tanks in the new biogas plant. The aim of this bachelor thesis is to assess a suitable evaporation system for a particular biogas plant. The evaporation system leads to the concentration of digestate by evaporation water. The system uses heat produced by cogeneration unit. The main consequence of the integration is lower cost for the transport of liquid digestate. The output of the bachelor thesis is a technical and economic evaluation that assesses the payback period depending on the flow of concentrated digestate. The specific costs for adjustment of liquid digestate with regard to the payback period are in the range of 5–15 years. The values do not exceed 210 (Kčyear)/t_fug . The values considering selling heat are even negative. The minimum value guaranteed by the manufacturer is around 260 (Kčyear)/t_fug . The integration of the evaporation system into Žamberk's biogas plant is economically disadvantageous. The thesis brings new knowledge about the potential of multi-stage flash evaporation in biogas plants with short transport distances and high utilization of waste heat.
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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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Measurement of selected physical properties of the waste water from biogas plant
Ondruška, Vojtěch ; Zejda, Vojtěch (referee) ; Vondra, Marek (advisor)
The aim of this Bachelor’s thesis is the experimental measurement of physical and chemical properties of the wastewater from biogas plants. Thesis concisely describes wastewater and its origin. The main part is dedicated to the design of experiments and to the detailed description of the measurement of selected properties with the available laboratory methods. Measured data are evaluated and compared to literature. The results of this thesis can be employed to further develop the equipment for thickening wastewater from biogas plants or to other scientific activity in the field of waste management in agriculture.
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Foaming of fermentation residues during a vacuum evaporation
Knob, Jan ; Brummer, Vladimír (referee) ; Vondra, Marek (advisor)
The diploma thesis deals with the processing of digestate, which is the remaining material after biogas production. It aims to experimentally prove how chosen operational parameters of antifoaming agents influence digestate foaming associated with the vacuum evaporating technology. Based on the research of available antifoamers and the issue of digestate foaming itself, it was observed how three selected antifoamers (i.e. rapeseed oil, silicone antifoamer Erbslöh Schaum-ex and oleic acid), together with the decrease in the pH factor of the evaporating digestate, influence the final foam production. For the purposes of the research, an apparatus simulating the vacuum evaporating process was set up in which the heated sample was brought to boil by gradual pressure decrease. The process of foaming was observed in a transparent cylinder of a testing culumn. The essential part of the experimental activity is represented by a planned experiment which by means of a DoE (Design of experiments) method proved rapeseed oil to be very efficient. In contrast, other antifoamers, as well as the influence of the pH factor decrease, manifested themselves as insignificant factors, while the oleic acid even supported the foaming. The supplementary measurements led to a more detailed research of the effects of rapeseed oil and to the construction of a mathematical model describing how the concentration of rapeseed oil undermines the amount of generated foam. The main contribution of the thesis is firstly the evidence that rapeseed oil plays an important part in the reduction process of digestate foaming and secondly the determination of minimum substance concentration leading to the foaming reduction of a particular sample which is considered efficient enough to enable functioning of a vacuum evaporator. The thesis has also experimentally demonstrated the influence of some polymer organic flocculants which have been proved to support the foaming.
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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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