Rapid Bio-methanation of Syngas by High Cell-density in Reverse Membrane Bioreactors

Syngas fermentation via gasification is a two-stage process, which contains gasification of feedstock into syngas and syngas bio-methanation by anaerobic microorganisms. This project is a study on syngas fermentation. The gasification feedstock can be difficult-to-degrade solid waste so; waste volumes are reduced while green energy is produced. The main target of this thesis was to study novel configurations of reverse membrane bioreactor (RMB) in order to retain microbial cells inside the digester and thereafter increase methane production. In the first experiment, microbial cells encased in PVDF sachets were proved to perform efficiently in batch mode in comparison to free cells at optimum temperature, 55 oC. Moreover, encased cells in co-digestion of syngas and organic waste exhibited higher methane amounts compared to pure syngas treatment. Encased cells were then tested in thermophilic semi-continuous process and showed better performance compared to the free cell reactor. The RMB containing encased cells retained successfully the cells during the 154 days of the experiment, while free cells were washed-out. The highest amounts of methane from RMB and the free cell reactor were produced during the 126th - 130th day (6 and 1.5 mmol/day, respectively). In the last experiment, a RMB containing 13 membrane layers of enclosed cells was studied and compared to a conventional reactor of free cells. The RMB performed successfully in syngas bio-methanation under semi-continuous conditions during 49 days. The highest methane amount produced was 10 mmol/day in both RMB and free cell reactor.Program: Industriell biotekni

The effectiveness of the Bobath neurodevelopmental treatment and Halliwick hydrotherapy in the treatment of children with cerebral palsy

The purpose of this study was to investigate the impact of Halliwick Hydrotherapy on the gross mobility, balance, speed and daily skills of children with cerebral palsy as well as the translation and weighting of specific water assessment trials in the Greek population. The study involved 85 children, including 80 with GMFCS. The duration of the intervention was 9 months. All children were evaluated through the GMFM, PEDI, TUG, PBS assessment trials, while the water intervention team was further evaluated through the WOTA 1 & 2, SWIM, HAAR special tests. A significant improvement was noted in the final evaluations at the end of nine months' intervention. In gross mobility, the water intervention group showed an improvement from an average of 56.64 (SD: 23.21) to 62.74 (SD: 24.54), while the land intervention group averaged 58.64 (SD: 22.76), at 61.42 (SD: 22.68). In the daily life skills, the water intervention team averaged 52.09 (SD: 20.14), at 59.17 (SD: 21.21), while the land intervention group averaged 52.43 (SD: 19.25) before intervention, at 55.20 (SD: 19.72) after intervention. In the balance, the water intervention team averaged 23.75 (SD: 16.30) before intervention, at 27.55 (SD: 17.18), while the land intervention group average 23.09 (SD: 15.00) before intervention, at 25.06 (SD: 15.19) At the speed, the water intervention team showed a decrease in TUG execution time in sec from an average of 16.25 (SD: 10.78) before intervention, at 14.96 (SD: 11.01), while the land intervention team averaged 17.85 (SD: 10.26), at 16.96 (SD: 10.69). In the adaptation to the aquatic environment, WOTA 1, 22.65 (SD: 6.68) to 32.10 (SD: 7.03), WOTA 2, 25.70 (SD: 10.68) to 44.60 (SD: 9.75), SWIM, 30.45 (SD: 7.86) to 41.12 (SD:5.94), and HAAR from 18.07 (SD: 3.34) to 23.40 (SD: 3.61). Water Assessment tools have been found to be highly reliable and appropriate to investigate changes over time. Inter-rater reliability (ICCs), WOTA 1: 0.997, WOTA 2: 0.999, SWIM: 0.989, HAAR: 0.948, while test-retest reliability (ICCs), WOTA 1: 0.989, WOTA 2: 0.997, SWIM: 0.981, HAAR: 0.951 and validity WOTA1, rP = 0.63, WOTA2, rP = 0.58, SWIM, rP = 0.59, GMFM and HAAR, rP = 0.54, (p <0.05).Σκοπός αυτής της μελέτης ήταν η διερεύνηση της επίδρασης της υδροθεραπείας Halliwick στην αδρή κινητικότητα, την ισορροπία, την ταχύτητα και τις καθημερινές δεξιότητες των παιδιών με εγκεφαλική παράλυση, καθώς και η μετάφραση και η στάθμιση ειδικών δοκιμασιών αξιολόγησης στο νερό στον ελληνικό πληθυσμό. Στη μελέτη συμμετείχαν 85 παιδιά, εκ των οποίων 80 με εγκεφαλική παράλυση διαφόρων επιπέδων GMFCS. Η διάρκεια της παρέμβασης ήταν 9 μήνες. Όλα τα παιδιά αξιολογήθηκαν μέσω των δοκιμασιών αξιολόγησης GMFM, PEDI, TUG, PBS, ενώ η ομάδα παρέμβασης στο νερό αξιολογήθηκε περαιτέρω μέσω των ειδικών δοκιμασιών WOTA 1 & 2, SWIM, HAAR. Σημαντική βελτίωση παρατηρήθηκε στις τελικές αξιολογήσεις μετά το πέρας της παρέμβασης των εννιά μηνών. Στην αδρή κινητικότητα, η ομάδα παρέμβασης στο νερό έδειξε βελτίωση από μέσο όρο 56.64 (SD: 23.21) σε 62.74 (SD: 24.54), ενώ η ομάδα παρέμβασης στην ξηρά από μέσο όρο 58.64 (SD: 22.76), σε 61.42 (SD: 22.68). Στις δεξιότητες καθημερινής ζωής, η ομάδα παρέμβασης στο νερό από μέσο όρο 52.09 (SD: 20.14), σε 59.17 (SD: 21.21), ενώ η ομάδα παρέμβασης στην ξηρά από μέσο όρο 52.43 (SD: 19.25) πριν την παρέμβαση, σε 55.20 (SD: 19.72) μετά την παρέμβαση. Στην ισορροπία, η ομάδα παρέμβασης στο νερό από μέσο όρο 23,75 (SD: 16.30) πριν την παρέμβαση, σε 27,55 (SD: 17.18), ενώ η ομάδα παρέμβασης στην ξηρά από μέσο όρο 23.09 (SD: 15.00) πριν την παρέμβαση, σε 25.06 (SD: 15.19). Στην ταχύτητα η ομάδα παρέμβασης στο νερό έδειξε μείωση στο χρόνο εκτέλεσης του TUG σε sec από μέσο όρο 16.25 (SD: 10.78) πριν την παρέμβαση, σε 14.96 (SD: 11.01), ενώ η ομάδα της παρέμβασης στην ξηρά από μέσο όρο 17.85 (SD: 10.26), σε 16.96 (SD: 10.69). Στην προσαρμογή στο υδάτινο περιβάλλον, WOTA 1, 22.65 (SD: 6.68) σε 32.10 (SD: 7.03), WOTA 2, 25.70 (SD: 10.68) σε 44.60 (SD: 9.75), SWIM, 30.45 (SD: 7.86), σε 41.12 (SD:5.94) και HAAR από 18.07 (SD: 3.34) σε 23.40 (SD: 3.61). Οι δοκιμασίες αξιολόγησης του νερού έχουν βρεθεί ότι είναι ιδιαίτερα αξιόπιστες και κατάλληλες για να ερευνήσουν τις αλλαγές με την πάροδο του χρόνου. Inter-rater reliability (ICCs), WOTA 1: 0.997, WOTA 2: 0.999, SWIM: 0.989, HAAR: 0.948, ενώ test-retest reliability (ICCs), WOTA 1: 0.989, WOTA 2: 0.997, SWIM: 0.981, HAAR: 0.951 και validity WOTA1, rP = 0.63, WOTA2, rP = 0.58, SWIM, rP = 0.59, GMFM και HAAR, rP = 0.54, (p <0.05)

Floating membrane bioreactors with high gas hold-up for syngas-to-biomethane conversion

The low gas-to-liquid mass transfer rate is one of the main challenges in syngas biomethanation. In this work, a new concept of the floating membrane system with high gas hold-up was introduced in order to enhance the mass transfer rate of the process. In addition, the effect of the inoculum-to-syngas ratio was investigated. The experiments were conducted at 55 °C with an anaerobic mixed culture in both batch and continuous modes. According to the results from the continuous experiments, the H2 and CO conversion rates in the floating membrane bioreactor were approximately 38% and 28% higher in comparison to the free (suspended) cell bioreactors. The doubling of the thickness of the membrane bed resulted in an increase of the conversion rates of H2 and CO by approximately 6% and 12%, respectively. The highest H2 and CO consumption rates and CH4 production rate recorded were approximately 22 mmol/(L·d), 50 mmol/(L·d), and 34.41 mmol/(L·d), respectively, obtained at the highest inoculum-to-syngas ratio of 0.2 g/mL. To conclude, the use of the floating membrane system enhanced the syngas biomethanation rates, while a thicker membrane bed resulted in even higher syngas conversion rates. Moreover, the increase of the inoculum-to-syngas ratio of up to 0.2 g/mL favored the syngas conversion

Учебная программа по учебной дисциплине "Гидро- и пневмопривод и гидропневмоавтоматика"

Учебная программа "Гидро- и пневмопривод и гидропневмоавтоматика" кафедры "Нефтегазоразработка и гидропневмоавтоматика" для дневной и заочной форм получения образования: общее количество часов-136, трудоемкость учебной дисциплины — 3 з.е., форма контроля знаний — экзамен

Effects of Heavy Metals and pH on the Conversion of Biomass to Hydrogen via Syngas Fermentation

The effects of three heavy metals on hydrogen production via syngas fermentation were investigated within a metal concentration range of 0-1.5 mg Cu/L, 0-9 mg Zn/L, 0-42 mg Mn/L, in media with initial pH of 5, 6 and 7, at 55 °C. The results showed that at lower metal concentration, pH 6 was optimum while at higher metal concentrations, pH 5 stimulated the process. More specifically, the highest hydrogen production activity recorded was 155.28% ± 12.02% at a metal concentration of 0.04 mg Cu/L, 0.25 mg Zn/L, and 1.06 mg Mn/L and an initial medium pH of 6. At higher metal concentration (0.625 mg Cu/L, 3.75 mg Zn/L, and 17.5 mg Mn/L), only pH 5 was stimulating for the cells. The results show that the addition of heavy metals, contained in gasification-derived ash, can improve the production rate and yield of fermentative hydrogen. This could lead in lower costs in gasification process and fermentative hydrogen production and less demand for syngas cleaning before syngas fermentation

Effects of Heavy Metals and pH on the Conversion of Biomass to Hydrogen via Syngas Fermentation

The effects of three heavy metals on hydrogen production via syngas fermentation were investigated within a metal concentration range of 0-1.5 mg Cu/L, 0-9 mg Zn/L, 0-42 mg Mn/L, in media with initial pH of 5, 6 and 7, at 55 °C. The results showed that at lower metal concentration, pH 6 was optimum while at higher metal concentrations, pH 5 stimulated the process. More specifically, the highest hydrogen production activity recorded was 155.28% ± 12.02% at a metal concentration of 0.04 mg Cu/L, 0.25 mg Zn/L, and 1.06 mg Mn/L and an initial medium pH of 6. At higher metal concentration (0.625 mg Cu/L, 3.75 mg Zn/L, and 17.5 mg Mn/L), only pH 5 was stimulating for the cells. The results show that the addition of heavy metals, contained in gasification-derived ash, can improve the production rate and yield of fermentative hydrogen. This could lead in lower costs in gasification process and fermentative hydrogen production and less demand for syngas cleaning before syngas fermentation

Innovative Pretreatment Strategies for Biogas Production

Biogas or biomethane is traditionally produced via anaerobic digestion, or recently bythermochemical or a combination of thermochemical and biological processes viasyngas (CO and H2) fermentation. However, many of the substrates feedstocks haverecalcitrant structure and difficult to digest (e.g., lignocelluloses or keratins), or theyhave toxic compounds (such as fruit flavors or high ammonia content), or not digestibleat all (e.g., plastics). To overcome these challenges, innovative strategies for enhancedand economically favorable biogas production were proposed in this review. Thestrategies considered are commonly known physical pretreatment, rapid decompression,autohydrolysis, acid- or alkali pretreatments, solvents (e.g. for lignin or cellulose)pretreatments or leaching, supercritical, oxidative or biological pretreatments, as well ascombined gasification and fermentation, integrated biogas production an

Bio‑hydrogen and VFA production from steel mill gases using pure and mixed bacterial cultures

A major source of CO2 emissions is the flaring of steel mill gas. This work demonstrated the enrichment of carboxydotrophic bacteria for converting steel mill gas into volatile fatty acids and H2, via gas fermentation. Several combinations of pure and mixed anaerobic cultures were used as inoculum in 0.5-L reactors, operated at 30 and 60 °C. The process was then scaled up in a 4-L membrane bioreactor, operated for 20 days, at 48 °C. The results showed that the enriched microbiomes can oxidize CO completely to produce H2/H+ which is subsequently used to fix the CO2. At 30 °C, a mixture of acetate, isobutyrate and propionate was obtained while H2 and acetate were the main products at 60 °C. The highest CO conversion and H2 production rate observed in the membrane bioreactor were 29 and 28 mL/LR/h, respectively. The taxonomic diversity of the bacterial community increased and the dominant species was Pseudomonas