O presente estudo avaliou o efeito do TDH (tempo de detenção hidráulica) (24 a 1 h) na produção de H2 em reator anaeróbio de leito granular expandido (Expanded Granular Slugde Bed) (ESGB) sob condições mesofílicas (30 ± 2 °C), com cultura mista e a partir do caldo de cana nas concentrações: 5, 10 e 15 g L-1, nos reatores EGSB5, EGSB10 e EGSB15, respectivamente. Foram atingidos valores máximos de produção volumétrica de H2 (PVH) ao decrescer o TDH para: 1 h no EGSB5 (6,96 L d-1 L-1); 1 h no EGSB10 (19,14 L d-1 L-1); e 2 h no EGSB15 (52,40 L d-1 L-1). Os resultados corroboram a afirmação de que reatores de alta taxa como o EGSB suportam aplicação de cargas mais elevadas, visto que o rendimento de H2 (Hydrogen Yield) (HY) máximo (0,73 mol H2 mol-1 hexose) foi observado no EGSB15 para a taxa de carregamento orgânico (TCO) igual a 182,9 kgcarboidrato m-3 d-1. Os HY visualizados no presente estudo foram inferiores aos observados nos estudos em que utilizaram culturas puras, isto pode ocorrer devido ao fato de que o tratamento térmico não é capaz de selecionar apenas culturas produtoras de H2. Foram identificados os possíveis consumos de H2 em consequência à homoacetogênese, com percentuais máximos de ácido acético (HAc) de 59,0 %, 50,0 % e 25,0 % em relação aos demais metabólitos produzidos nos EGSB5, EGSB10 e EGSB15, respectivamente. Devido à provável ocorrência de homoacetogênese o H2 detectado não pode ser inteiramente atribuído a presença de HAc, atribui-se então a produção de H2 à rota de produção de ácido butírico (HBu). Coincidentemente com o HY máximo, as concentrações e percentuais de HBu foram de 1,95 g L-1 e 44,0 % para o EGSB10 no TDH de 4 h, e de 4,07 g L-1 e 43,0 % para o EGSB15 no TDH de 2 h. De modo geral, a redução do TDH de 24 a 1 h melhorou a produtividade de H2. Observou-se devido à elevada PVH, que o caldo de cana pode ser uma alternativa viável para a produção de H2 em larga escala. / The present study evaluated HRT (hydrualic retention time) (24 to 1 h) effect on H2 production in anaerobic expanded granular sludge bed reactor (ESGB) under mesophilic conditions (30 ± 2°C), with mixed culture and sugarcane juice concentration of 5, 10 and 15 g L-1 in EGSB5, EGSB10 and EGSB15, respectively. Maximum hydrogen production rates (HPR) were visualized by decreasing TDH to: 1 h in EGSB5 (6.96 L d-1 L-1); 1 h at EGSB10 (19.14 L d-1 L-1); and 2 h in EGSB15 (52.40 L d-1 L-1). Results attest that high rate reactors such as EGSB support higher loads application, since maximum hydrogen yield (HY) was observed in EGSB15 for the highest organic loading rate (OLR) applied (0.73 mol H2 mol-1 hexose in OLR 182.9 kgcarboidrato m-3 d-1). HY visualized in present study were lower than those observed in studies using pure cultures, this may occur due to heat treatment is not able to select only H2 producing cultures. Possible H2 intakes were observed as a consequence of homoacetogenesis, with maximum acetic acid (HAc) 59.0%, 50.0% and 25.0% for EGSB5, EGSB10 and EGSB15, respectively. Due to probable occurrence of homoacetogenesis the H2 production can\'t be entirely attributed to HAc, then H2 production is attributed to butyric acid (HBu) route. Coincidentally with maximum HY, the HBu concentrations and percentages were 1.95 g L-1 and 44.0% for the EGSB10 in TDH 4 h, 4.07 g L-1 and 43.0% for EGSB15 in TDH 2 h. Overall, the TDH reduction from 24 to 1 h improved H2 productivity. Due to high HPR observed the sugarcane juice can be a feasible alternative for H2 production on large scale.

Στα πλαίσια της παρούσας μελέτης ερευνήθηκε η βιοτεχνολογική επεξεργασία αποβλήτων τυροκομείου με σκοπό την ενεργειακή αξιοποίηση τους. Ειδικότερα, μελετήθηκε η διεργασία παραγωγής υδρογόνου και μεθανίου από τον ορρό τυρογάλακτος, μέσω αναερόβιας επεξεργασίας, σε μια διεργασία δυο σταδίων, υπό μεσόφιλες συνθήκες. Στο πρώτο στάδιο μελετήθηκε η παραγωγή υδρογόνου του ορρού τυρογάλακτος μέσω της ζύμωσης των διαλυτών σακχάρων του. Πραγματοποιήθηκαν πειράματα σε αντιδραστήρα συνεχούς ανάδευσης, ο οποίος λειτούργησε σε υδραυλικούς χρόνους παραμονής 24, 18, και 12 h, είτε με προσθήκη αλκαλικότητας (ΝαHCO3 σε HRT=24h), είτε με χρήση αυτόματου ρυθμιστή του pH (KOH, 2Μ σε HRTs=24, 18 και 12h). Η στοιχειομετρική απόδοση σε υδρογόνο παρουσίασε μέγιστη τιμή με προσθήκη αλκαλικότητας σε υδραυλικό χρόνο παραμονής 24 h και ήταν ίση με 0.48 ± 0.03 mol H2 / mol καταναλισκόμενης γλυκόζης ή 2.4 L H2/ L τυρόγαλου/d και αποδόθηκε στην υψηλή παραγωγή βουτυρικού οξέος σε αυτές τις συνθήκες. Παράλληλα, πραγματοποιήθηκαν πειράματα σε αντιδραστήρα διαλείποντος έργου με χρήση καθαρής καλλιέργειας του μικροοργανισμού Ruminococcus albus. Από τα πειράματα προέκυψε ότι οι αποδόσεις ήταν αρκετά μικρότερες σε σχέση με τις παρατηρούμενες από άλλα υποστρώματα, γεγονός που αποδόθηκε στην αυξημένη παραγωγή αιθανόλης εις βάρος της παραγωγής υδρογόνου, αλλά και επειδή η κινητική μεταβολισμού των υδατανθράκων ήταν χαμηλή. Την μεγαλύτερη στοιχειομετρική απόδοση παρουσίασε η λακτόζη ως υπόστρωμα και η τιμή της ήταν 2.34 ± 0.02 mol H2/mol καταναλισκόμενων υδατανθράκων. Επίσης, μελετήθηκε η στοιχειομετρία των χημικών αντιδράσεων της ζύμωσης του ορρού τυρογάλακτος και υπολογίστηκε η απόδοση της διεργασίας για την παραγωγή κυττάρων και τελικών προϊόντων. Στο δεύτερο στάδιο μελετήθηκε η περαιτέρω μετατροπή του οργανικού φορτίου σε μεθάνιο με ταυτόχρονη μείωση του οργανικού φορτίου του αποβλήτου.Έγιναν πειράματα σε αντιδραστήρες διαλείποντος έργου για τον υπολογισμό του βιοχημικά μεθανογόνου δυναμικού του ορρού τυρογάλακτος και της απορροής του ζυμωτικού αναερόβιου αντιδραστήρα. Την μεγαλύτερη παραγωγικότητα σε μεθάνιο ανάμεσα στα δυο είχε το τυρόγαλο και συνολικά παρήχθησαν 18 L CH4/ L υποστρώματος που καταναλώθηκε. Επιπλέον, μελετήθηκε η αναερόβια χώνευση της απορροής του ζυμωτικού αντιδραστήρα σε μεθανογόνο χωνευτήρα συνεχούς ανάδευσης σε υδραυλικούς χρόνους παραμονής 20 και 30 d, συμπεραίνοντας ότι η μεγαλύτερη παραγωγικότητα σε μεθάνιο παρατηρήθηκε σε HRT = 30 d, ήταν ίση με 14.55 L CH4 / L τροφοδοσίας και η απομάκρυνση του COD ήταν μεγαλύτερη από 90% στις μόνιμες καταστάσεις, ενώ χρησιμοποιήθηκε το μαθηματικό μοντέλο ADM1 για την πρόβλεψη της συμπεριφοράς του μεθανογόνου αντιδραστήρα στους χρόνους παραμονής όπου λειτούργησε. / In the present study, the biotechnological exploitation of wastewaters from a cheese manufacturing process was researched. In particularly, the process of hydrogen and methane production from cheese whey in a two-stage continuous process under mesophilic conditions was studied. In the first stage, the fermentative hydrogen production from undiluted cheese whey was investigated at hydraulic retention times (HRT) of 24, 18 and 12 h in a continuous stirred tank reactor. Alkalinity addition (NaHCO3 in HRT=24h) or an automatic pH controller (KOH, 2Μ in HRTs=24, 18 and 12h) were used. The highest hydrogen production rate was 2.4 L/L reactor/d, while the yield of hydrogen produced was approximately 0.48 ± 0.03 mol H2/mol glucose consumed, with alkalinity addition and they were attributed to increased butyric acid production. Also, experiments with the use of batch reactor were done to investigate the efficiency of hydrogen production using pure cultures of the bacterium Ruminococcus albus. The results showed that the hydrogen yield was low compared to other substrates, and this was attributed to an increased production of ethanol compared to hydrogen and to a lower carbohydrate metabolic rate. The maximum yield of hydrogen production for lactose was 2.34 ± 0.02 mol H2/mol carbohydrates consumed. Also, the stoichiometry of the chemical reactions for the fermentation was studied and the process yield for cell production and energy were calculated. In the second stage, the conversion of the organic load to methane gas was studied. Batch reactors were used in order to study the biochemical methane potential of cheese whey and the effluent of the hydrogenogenic reactor. The highest methane production was observed for the whey and it was in total 18 L CH4/ L substrate consumed. Moreover, the anaerobic digestion of the effluent from the fermenting reactor was conducted in a conventional CSTR reactor and for HRTs of 20 and 30 d. The highest methane production was observed for the latter HRT. It equaled 14.55 L CH4 / L feed and the COD removal was more than 90% at steady state. The process of the anaerobic digestion was analyzed and simulated with the use of the anaerobic digestion model No 1 (ADM1).

Support and investment´s subsidies of production of electricity from renewable sources after 2009 made a phenomenon from a biogas plants. This thesis specifies the most used feedstock for biogas production in the Czech Republic. Each substrate used in biogas plants, have different chemical composition, dry matter content, thus providing another volume of biogas. Specifications of elections of substrate, was made on the based on consultations with the operators of agricultural biogas plants. Stabilized anaerobic process increases the production of biogas and supports economic situation of farms.

The diploma thesis is focused on the topic of an important and working of biogas plants. Literature review is focused on working of biogas plants - their kinds, possible inputs and outputs and naturally processes. The aim of practical part is a research, which is concentrated on quantity and quality of inputs for maintain an optimal running of biogas plant, even in crisis periods (like is lack of harvest in poor year). And also it is focused on profitability poor year against average year.

This diploma thesis deals with the bioreactor system and its use for the production of heat and biogas. The bioreactor uses the composting and metanogation process of fermentation that humanity has known for hundreds of years, but the combination of these processes is a relatively unexplored area. The theoretical part of the thesis analyzes the existing possibilities of utilization of the heat generated in the compost, and also describes the used technology of small biogas stations and other small systems for biogas production. It follows the practical part of the work, when it was the task to design a bioreactor working at low temperatures during the winter. Part of the solution is the initial design and testing of the basic test structure of the bioreactor, followed by the implementation of a more advanced and more complex system, including a control and measuring center realized by a microcontroller.

The master’s thesis is focused on the possibility of using biodegradable materials (animal manure, energy crops, crop waste) in a biogas plant. The first part deals with the mechanism of production of biogas. Described are factors which affect the production of biogas, its composition, properties, utilization and potential substrates. The next chapter deals with the technologies of biogas plants. The main part of the thesis is devoted to a proposal of a specific biogas plant in the Slovak Republic in the Novozámocký district. Included is the processing of design proposal, selection of components and proposal of the layout of biogas plant. The economic evaluation includes quantifying capital and operating costs and profits from the sale of electricity and compost.

The main topic of this thesis is a research of influence of disintegration of sewage sludge on the production of biogas during the process of anaerobic fermentation. The theoretical part deals with issues and specific methods used during the process of waste water cleaning, furthermore it contains simplified description of waste water treatment plants and particular devices. The number of ways of processing sewage sludge and its potential utilization id also discussed. Following parts of the thesis analyze in detail my own process of anaerobic fermentation including important factors influencing this process. Comparison of aerobic and anaerobic fermentation and ecological perspective on the issue are included in this part. Another important part of the thesis deals with disintegration and description of the disintegration methods and devices. The fundamental part implies the analysis of the executed experiments. Experiments analyze the growth of biogas during anaerobic fermentation depending on the disintegration of sewage sludge. After that the evaluation of the experiments is stated together with economical calculations of the disintegration process executed in laboratory conditions.

Hydrogen production by means of anaerobic fermentation was researched utilizing three different substrates. Synthetic wastewater, dairy manure, and cheese whey were combined together at different concentrations under batch anaerobic conditions to determine the optimal hydrogen producing potential and waste treatment of each. Cheese whey at a concentration of 55% was combined with dairy manure at a concentration of 45% to produce 1.53 liters of hydrogen per liter of substrate. These results are significant because the control, synthetic wastewater, which was a glucose-based substrate, produced less hydrogen, 1.34 liters per liter of substrate, than the mixture of cheese whey and dairy manure. These findings indicate that cheese whey and dairy manure, which are of little value, have potential to produce clean combusting hydrogen fuel. The effluent from the anaerobic hydrogen fermentations was then placed into a second continuous-fed reactor as part of a two-phase anaerobic digestion system. This system was designed to produce hydrogen and methane for a mixture of approximately 10% hydrogen. The two-stage process also further treated the synthetic wastewater, dairy manure, and cheese whey. The two-phase anaerobic methanogenic reactor was shown to produce more methane in the second phase (56 L IBR anaerobic digester), 1.36 mL per minute per liter substrate, as compared to the single-phase anaerobic reactor (56 L IBR), which produced 1.22 mL per minute per liter substrate. In general, this research has suggested that agricultural and food processing wastes provide the needed nutrients for hydrogen production and that a two-phase anaerobic digestion system is ideally set up to produce hydrogen-methane mixtures while treating wastes for discharge into the environment.

FREITAS, A. V. Utilização de membranas de contato (Hollow fiber) para extração e re-extração de ácido capróico. 2016. 109 f. Dissertação (Mestrado em Engenharia Química)-Centro de Tecnologia, Universidade Federal do Ceará, Fortaleza, 2016. / Submitted by Marlene Sousa (mmarlene@ufc.br) on 2017-09-15T19:04:34Z No. of bitstreams: 1 2017_dis_avfreitas.pdf: 9293878 bytes, checksum: 9ae6812d702c7c88db26d7fb6662bcbd (MD5) / Approved for entry into archive by Marlene Sousa (mmarlene@ufc.br) on 2017-09-18T10:47:42Z (GMT) No. of bitstreams: 1 2017_dis_avfreitas.pdf: 9293878 bytes, checksum: 9ae6812d702c7c88db26d7fb6662bcbd (MD5) / Made available in DSpace on 2017-09-18T10:47:43Z (GMT). No. of bitstreams: 1 2017_dis_avfreitas.pdf: 9293878 bytes, checksum: 9ae6812d702c7c88db26d7fb6662bcbd (MD5) Previous issue date: 2016-07-22 / Caproic acid or hexanoic acid has a wide range of applications in the pharmaceutical, chemical and food industries. The utilization of a fermentative production route has been studied as an alternative to petrochemical route, which relies on non-renewable resources. In the fermentative route, it is essential to provide a continuous caproic acid extraction from the biotic medium, because the accumulation of this acid inhibits microorganisms. In this study, the extraction and re-extraction of caproic acid by contact membranes are investigated in detail. This extraction system involves reactive and diffusive processes in two stages: i) the extraction step, where caproic acid passes through selectivity to an extraction solution (mineral oil + 3% trioctylphosphine (TOPO)); ii) the re-extraction step, where the caproic acid passes through affinity to an alkaline solution (0.5M H3BO3, pH ≥ 9.0). This type of extraction system has advantages over conventional liquid-liquid extraction of organic acids, because the membrane has hydrophobic characteristics, and acts as a physical barrier, which prevents the liquid phases dispersion. LIQUICEL two membranes are used (model 2.5 x 8.0 Extra-Flow), with surface area of 1.4 m², volume of the inner hull of 0.15 L (150 ml) and volume of the outer hull of 0.40 L (400ml). Each membrane has 800 hollow fibers of polypropylene (internal diameter 0.24 mm, length 15 cm, 0.03 mm thick wall and 0.03 mM of pore size of the membrane with 40% porosity). The mass transfer rates of membrane system were determined for different operating conditions from the effluent using a bioreactor and a pure (caproic acid diluted in water) effluents. In these experiments the caproic acid concentrations ranged between 0.1 and 2.5 g.L-1, which is a representative range for reactors operated at pH 5.5. The flow rates of the acidic and alkaline solutions ranged from 9,2 a 219,4 m.d-1. During the assays, pH, and caproic acid concentrations were monitored. The experiments using synthetic effluent showed that mass transfer rates in the extraction membranes are 9,5 g.m-2.h-1, and achieved extraction efficiency of 96%. Using the bioreactor effluent, the mass transfer rates were 3,67 g.m-2.h-1, and extraction effiency was 43%. Additionally, from these tests, it is possible to observe that the extraction rates are directly proportional to the liquid velocity in the external parts of the membranes. These results confirm that the maximum rates of extraction and re-extraction of the contact membrane system are in a feasible range to be used together with anaerobic reactors for producing caproic acid. / Ácido Caproico, ou hexanóico, tem uma ampla gama de aplicações nas indústrias farmacêutica, química e alimentícia. A utilização de uma via de produção fermentativa tem sido estudada como uma alternativa à via petroquímica, que depende de recursos não renováveis. Na via fermentativa é essencial um processo contínuo de extração de ácido capróico a partir do meio biótico, uma vez que a acumulação deste ácido inibe a microbiota. Neste trabalho, a extração e re-extração do ácido capróico por membranas de contato são investigadas. O sistema de extração envolve processos difusivos e reativos e em duas etapas: i) uma etapa de extração, em que o ácido capróico é transferido através de seletividade para a solução de extração (óleo mineral + 3% de trioctilfosfina (TOPO)); ii) uma etapa de reextração, na qual o ácido caproico passa para uma solução alcalina (0,5 M de ácido bórico (H3BO3), pH ≥ 9,0) por afinidade. Este tipo de extração tem vantagens em relação à extração líquido-líquido convencional de ácidos orgânicos, pois a membrana possui características hidrofóbicas, que atua como uma barreira física impedindo a dispersão das fases líquidas. São utilizadas duas membranas Liquicel (modelo 2,5 x 8,0 Extra-Flow), com área superficial de 1,4 m², volume do casco interno de 0,15 L (15 0ml) e volume do casco externo de 0,40 L (400 ml). Cada membrana possui 800 fibras ocas de polipropileno (com diâmetro interno de 0,24 mm, 15 cm de comprimento, 0,03 μm de espessura da parede e 0,03 μm de tamanho dos poros da membrana com 40% de porosidade). As taxas de transferência de massa do sistema de membrana foram determinadas para diferentes condições de funcionamento a partir de um efluente oriundo de um biorreator e um efluente sintético (ácido capróico diluído em água). Nestes experimentos as concentrações de ácido capróico variaram de 0,1 a 2,5 g/L, que é uma faixa representativa para os reatores operados com pH 5,5. As vazões das soluções ácidas e alcalinas variaram de 9,2 m.d-1 a 219,4 m.d-1. Durante os testes, o pH e as concentrações de ácido capróico foram monitorados. Os experimentos utilizando solução pura mostram taxas de transferência de massa máxima nas membranas de extração 9,5 g.m-2.h-1, com uma eficiência de 96%. Utilizando o efluente oriundo de um biorreator essas taxas de transferência de massa máxima foi 3,67 g.m-2.h-1, com uma eficiência de 43%. Adicionalmente, a partir destes experimentos, é possível observar que as taxas de extração são diretamente proporcionais à velocidade do líquido nas partes externas das membranas. Estes resultados confirmam que as taxas máximas de extração e re-extração do sistema de membrana de contato estão em uma faixa que pode viabilizar a utilização deste sistema em conjunto com reatores anaeróbios que produzem ácido capróico.

The aim of this thesis is to design a fermentation unit specially adjusted for household operating. Unit processes kitchen and garden biodegradable waste with requirements of low acquisition costs, operating costs and demands of service. Benefits of this unit are production of biogas, which will be utilized in household, and processed of biodegradable waste to nutritious manure. The first part of the work is aimed on description of anaerobic fermentation process and summary of operating conditions. The main part deals with potential of household and garden biodegradable waste for production of biogas and design of fermentation unit. Proposals for biogas utilization and economy of whole project are mentioned.