Удосконалення процесу миття поверхонь технологічного обладнання молочної галузі
| dc.contributor.author | Кравченюк, Христина Юріївна | |
| dc.date.accessioned | 2020-10-08T12:49:20Z | |
| dc.date.issued | 2019 | |
| dc.description | Dissertation with a view to obtaining the academic degree of Candidate of Sciences in the specialty 03.00.20 «Biotechnology». National University of Life and Environmental Sciences of Ukraine. Kyiv, 2019. The thesis discusses the substantiation of adhesive properties of biofilm formation and degradation on milk industry production equipment and technological parameters under sanitary treatment conditions. Some analytical review of the influence of biofilms formation by bacteria with different morphological and physiological characteristics due to the specific use of production and auxiliary equipment with certain roughness of stainless-steel surface and its behavior after sanitary treatment has been made in the thesis. The main reason of microflora survival on the equipment surfaces after their disinfection in so called «dead zones» (bends, joints, gaskets, valves, cracks, scratches) due to the biofilm formation has been discovered. It was found out that there were approximately 1000 microorganisms formed in biofilms on the equipment where at least one plankton bacterium was found. Stainless steel surfaces in the different types of machines have been classified according to the surface roughness characteristics that eventually defines the process operation. The prospects of using the instruments and machines for the sanitary treatment of equipment have been determined. The purpose and objectives of the thesis under discussion have been stated on the basis of the analysis of specific features of biofilms formation by some bacteria, advantages and disadvantages of process sanitary treatment, peculiarities of material and energy flows transformation. The investigation in this field will make possible to determine and substantiate scientifically the parameters of sanitary treatment of production equipment aimed at maximum reduction of microbial adhesion process resulted in efficient degradation of biofilms and high-quality products manufacture. A framework of conducting the theoretical and experimental study divided into four stages has been given. Some plates made of stainless corrosion-resistant nickelchromium austenitic steel AISI 321 (standard of American institute of steel and alloys) of 30×30 mm size and of thickness 1,2 mm, of the surface roughness Ra=2.68±0.014 mkm, Ra=0.95±0.092, Ra=0.63±0.087, Ra=0.30±0.065, Ra=0.25±0.035, Ra=0.24±0.026 and Ra=0.16±0.018 mkm have been used in the research. The necessary methods and tools for conducting the research have been developed. The considerable part of the paper under discussion is devoted to the physics of biofilm formation mechanism, biofilm development character, determination of contamination by the microorganisms of the surfaces of production equipment and milk products at milk processing enterprises. We came to the conclusion that the more contaminated is the surface by the microorganisms the quicker film formation process and dense biofilms formation process are taking place. We have discovered that E. сoli and Е. faecalis. biofilms formation is considerably influenced by both the surface roughness and initial number of bacteria. It was found that under the same conditions E. coli biofilm had lower density comparing to the Е. faecalis biofilm on the stainless-steel surface. The mathematicalstatistical processing of the research results has been conducted by the method of regression-correlation analysis. Theoretical study of pipe-line liquid motion dynamics has allowed to discover the following phenomena: some eddy formation can be observed, the liquid reverse motion takes place, the flow separation from the joint surface occurs. All this eventually resulted in considerable speed and pressure losses. The process of adhesive bond elimination, i. e. biofilm degradation, due to its separating from the surface by different cleaning agents when we need some efforts to overcome the hydrodynamic resistance and internal stress has been taken into consideration. The theoretical modeling has proved that the process of stainless-steel biofilm degradation under sanitary treatment conditions will be the most difficult at the surface roughness 2.68–0.95 mkm. It can be explained by the fact that both coccus and string formed bacteria formed from the biobifilm can be found in the surface depressions. Meanwhile, at steel surface roughness 0.63–0.16 mkm the formed biofilms are less protected by the surface depressions so the process of degradation will take place more quickly. The necessary mathematical simulation of a bacterial film adhesion in the transport system has been conducted which was conveniently classified into two cases: when bacterial slime removal is taking place on the elbow surface and when there isn’t any slip ratio. It was found that the degree of surface treatment is influenced by physical-chemical properties of film medium, hydrodynamic state of the system, its dissipative characteristics, the level and degree of power input area, kinematic parameters of liquid phase and bacterial film contact on the rough surfaces of material pipe.The synthesis of the ejector integrated model for the sanitary treatment of pipelines has been conducted on the basis of continuum mechanics, CFD-methods (Computational Fluid Dynamics), when the system of Navier-Stokes or Reynolds equations has been solved by numerical methods of calculating hydrodynamics dealing with liquid flow inside the ejector. We have found that the pressure equals to 0.367 MPa at the ejection device inlet and after components being mixed in the convergent zone the pressure is decreasing so that it is equal to 0,38 MPa at a distance of 13 mm from the components supply port. At the ejection device outlet, the average mixture pressure is 0.32 MPa. The obtained data have proved that it is much easier to remove the bacterial film by the proposed ejecting mechanism and enzyme Savinase®Evity 16L use for sanitary treatment. The use of the suggested ejector ensures the 0.8 % higher efficiency; 1.2 % reduction of maintenance costs; 3 % cost saving of an operator’s fees. Economic benefits of the developed design implementation 13523,94 hrn with payback period 3 months | uk_UA |
| dc.description.abstract | Дисертація на здобуття наукового ступеня кандидата технічних наук зі спеціальності 03.00.20 «Біотехнологія». Національний університет біоресурсів і природокористування України. Київ, 2019. Дисертацію присвячено обґрунтуванню адгезійних властивостей утворення та деградації біоплівки на технологічному обладнанні молочної галузі й технологічних параметрів при їх санітарній обробці. Розкрито основну суть виживання мікрофлори на поверхнях обладнання під час санобробки, у так званих «мертвих зонах» (згини, з’єднання, прокладки, клапани, тріщини, подряпини) за рахунок формування біоплівки. Встановлено закономірності процесу плівкоутворення на нержавіючій сталі з різною шорсткістю поверхні та виявлено, що за величини шорсткості Ra більше 0,95±0,092 мкм формуються щільні біоплівки незалежно від морфологічного складу мікрофлори. Водночас, адгезія та процес плівкоутворення сповільнюються бактеріями E. coli, E. faecalis та S. aureus за шорсткості поверхні нержавіючої сталі 0,16 мкм. Запропоновано оцінювати протиадгезивні властивості нержавіючої сталі за показником оптичної густини сформованих біоплівок S. aureus. На основі теоретичного й математичного моделювання процесу формування і деградації біоплівок на поверхні нержавіючої сталі з різною шорсткістю під час санітарної обробки, запропоновано використання ежекторного пристрою з 0,1 % мийним засобом «Ензимий, що дозволяють зменшення прикріплення мікроорганізмів до поверхні та зниження контамінації молочних продуктів. Проведено апробацію результатів дисертаційного дослідження в промислових умовах. Розроблено та захищено патентами нові технічні рішення для технологічного процесу санобробки обладнання | uk_UA |
| dc.identifier.citation | Удосконалення процесу миття поверхонь технологічного обладнання молочної галузі: автор. дис. ...кандидата технічних наук: 05.00.20 "Біотехнологія" (технічні науки) / Х.Ю. Кравченюк ; Національний університет біоресурсів і природокористування України. - К., 2019. - 23 с. | uk_UA |
| dc.identifier.uri | https://dglib.nubip.edu.ua/handle/123456789/1022 | |
| dc.language.iso | uk | uk_UA |
| dc.publisher | НУБіП України | |
| dc.subject | бактеріальна біоплівка | uk_UA |
| dc.subject | адгезія | uk_UA |
| dc.subject | санобробка | uk_UA |
| dc.subject | ежектор | uk_UA |
| dc.subject | математична модель | uk_UA |
| dc.subject | bacterial biofilm | |
| dc.subject | adhesion | |
| dc.subject | sanitary treatment | |
| dc.subject | ejector | |
| dc.title | Удосконалення процесу миття поверхонь технологічного обладнання молочної галузі | uk_UA |
| dc.type | ThesisAbstract | uk_UA |
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