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Pereira, Edson Rivelino. "Desempenho e caracterização microbiana do processo de dois estágios com reatores anaeróbios de fluxo ascendente com manta de lodo (UASB) tratando águas residuárias de suinocultura." Universidade de São Paulo, 2004. http://www.teses.usp.br/teses/disponiveis/18/18138/tde-26022007-170703/.
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Foram operados dois reatores UASB de bancada (volumes de 39,0 e 10,5 L) instalados em série, alimentados com águas residuárias de suinocultura com concentração de sólidos suspensos totais (SST), no primeiro reator, em torno de 5000 mg/L, com temperatura controlada (de 25 a 30 graus Celsius) e com tempo de detenção hidráulica (TDH) no primeiro reator de 62 a 16 h e no segundo de 16 a 4 h. O objetivo foi avaliar o desempenho e caracterizar física e microbiologicamente o lodo dos reatores UASB operados em dois estágios. Os resultados obtidos no ensaio 1, com TDH de 62 h no primeiro reator e SST no afluente de 5240 mg/L, mostraram eficiências de remoção de DQO total de 86% e 59% e SST de 82% e 57%, no primeiro e segundo reatores, respectivamente. A eficiência de remoção de DQO total e SST no sistema, no ensaio 1, foi de 95% e 94%. No ensaio 2, com TDH de 31 h no primeiro reator e SST de 5000 mg/L no afluente, observou-se eficiência de remoção de DQO total de 86% e 43% e SST de 85% e 58%, no primeiro e segundo reatores, respectivamente. A eficiência de remoção de DQO total e SST no sistema, no ensaio 2, foi de 92% e 94%. No ensaio 3, com TDH de 16 h no primeiro reator e SST de 5490 mg/L no afluente, observou-se eficiência de remoção de DQO total de 73% e 23% e SST de 65% e 20%, no primeiro e segundo reatores, respectivamente. A eficiência de remoção de DQO total e SST no sistema, no ensaio 3, foi de 79% e 73%. A TCOV aplicada no primeiro reator, no ensaio 1, foi de 4,55 kg DQO total/\'M POT.3\'.d, no ensaio 2 de 8,75 kg DQO total/\'M POT.3\'.d e no ensaio 3 de 18,65 kg DQO total/\'M POT.3\'.d. A produção de \'CH IND.4\' no primeiro reator foi de 17,50 a 68,20 L \'CH IND.4\'/d e no segundo reator de 1,62 a 5,50 L \'CH IND.4\'/d com a diminuição do TDH. Os reatores UASB instalados em série foram eficientes na remoção da fração dissolvida e, principalmente, da fração devido à concentração de SST do afluente. Para TCOV de 4,55 kg DQO/\'M POT.3\'.d no primeiro reator, pôde-se obter eficiências de remoção de DQO total e de SST acima de 90% e de DQO dissolvida acima de 85%. Para TCOV de 18,65 kg DQO/\'M POT.3\'.d no primeiro reator, as eficiências de remoção de DQO total e de SST foram acima de 70% e DQO dissolvida acima de 75%. As maiores produções específicas de metano foram obtidas com TCOV de 2,55 kg DQO/\'M POT.3\'.d para o segundo reator e de 8,65 kg DQO/\'M POT.3\'.d para o primeiro reator. A operação dos reatores UASB com valores de concentração de SST no afluente em torno de 5000 mg/L foram prejudiciais ao processo de granulação do lodo. Os grânulos apresentaram distribuição dispersa das morfologias microbianas ao longo da parede, não caracterizando a divisão em camadas definidas. As arqueas metanogênicas predominantes foram as semelhantes à Methanosaeta.Two bench scale UASB reactors (volumes of 39,0 and 10,5 L) were operated in sequence, fed with swine wastewater with total suspended solids (TSS) concentration around 5000 mg/L in the first reactor, with controlled temperature (from 25 to 30 Celsius degrees) and operating with hydraulic detention time (HDT) in the first reactor varying from 62 to 16 h and in the second reactor from 16 to 4 h. The objective was to evaluate the performance and to characterize physically and microbiologically the sludge from UASB reactors operated in two stages treating swine wastewater. The results obtained in phase 1, with HDT of 62 h in the first reactor and TSS in the influent of 5240 mg/L, presented total COD removal efficiencies of 86% and 59% and TSS reduction efficiency of 82% and 57%, in the first and second reactors, respectively. The removal efficiency of total COD and TSS in the system, in phase 1, was 95% and 94%, respectively. In the phase 2, using HDT of 31 h in the first reactor and TSS of 5000 mg/L in the influent, it was observed a total COD removal efficiency of 86% and 43% and TSS reduction efficiency of 85% and 58%, in the first and second reactors, respectively. The system removal efficiency of total COD and TSS in phase 2, was 92% and 94%, respectively. In phase 3, with a HDT of 16 h in the first reactor and TSS of 5490 mg/L in the influent, it was observed a total COD removal efficiency of 73% and 23% and TSS reduction efficiency of 65% and 20%, in the first and second reactors, respectively. The total COD removal efficiency and TSS reduction efficiency in the system, in phase 3, was 79% and 73%, respectively. The volumetric organic loading rate (VOLR) applied in the first reactor, in phase 1, was 4,55 kg total COD/\'M POT.3\'.d, in phase 2 was 8,75 kg total COD/\'M POT.3\'.d and in phase 3 was 18,65 kg total COD/\'M POT.3\'.d. The \'CH IND.4\' production in the first reactor was from 17,50 to 68,20 L \'CH IND.4\'/d and in the second reactor from 1,62 to 5,50 L \'CH IND.4\'/d decreasing the HDT in the experiment phases. The UASB reactor installed in sequence were efficient in the dissolved fraction removal and, mainly, to the fraction due to the TSS influent concentration. The total VOL value of 4,55 kg COD/\'M POT.3\'.d was measured in the first reactor, it was achieved TSS and total COD removal efficiencies above 90% and dissolved COD above 85%. For the OVL of 18,65 kg COD/\'M POT.3\'.d in the first reactor the TSS and total COD removal were above 70% and dissolved COD above 75%. The larger methane specific production was obtained with a total VOL of 2,55 kg COD/\'M POT.3\'.d in the second reactor and 8.65 kg COD/\'M POT.3\'.d in the first reactor. The UASB reactors operation with the TSS concentration values of 5000 mg/L in the influent was prejudicing the sludge granulation process. The granules present a microbial morphology disperse distribution that doesn\'t characterize a layers defined distribution. The predominant metonogenic archeas were similar to Methanosaeta.
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Ariunbaatar, Javkhlan. "Methods to enhance anaerobic digestion of food waste." Thesis, Paris Est, 2014. http://www.theses.fr/2014PEST1176/document.
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Le traitement des déchets alimentaires (FW) par digestion anaérobie peut conduire à une production d'énergie couplée à une réduction des émissions de volume et de gaz à effet de serre à partir de ce type de déchets. Néanmoins, l'obtention de la récupération du méthane la plus élevée possible dans un temps plus court avec un fonctionnement stable est difficile. Pour surmonter les obstacles de la MA de divers procédés de pré-traitement FW, la supplémentation en oligo-éléments, bioaugmentation utilisant la bouse des animaux de zoo et la comparaison des configurations de réacteurs, y compris une étape ou en deux réacteurs à cuve agités en continu (CSTR) et un réacteur à membrane anaérobie (AnMBR ) ont été étudiées dans le cadre de la présente recherche. Sur la base des résultats des expériences de traitement par lots, de pré-traitement thermique à 80 ° C pendant 1,5 heure cédés> 50% augmentation de la production de biométhane, et il a été trouvé à être plus économe en énergie que l'ozonation ou prétraitements de choc thermophiles. Parmi les différentes concentrations testées et les oligo-éléments, Fe (II) et Se (VI) des concentrations de 25 à 50 ug / L ont donné lieu à 39 et 35% d'augmentation de la production de biométhane, respectivement. Une meilleure solubilisation des protéines (6,96 ± 2,76% de plus) et de glucides récalcitrants (344,85 ± 54,31 mg / L par rapport à zéro) pourrait être obtenue avec bioaugmentation de girafe fumier (30% en volume), qui a donné un 11,24 ± 4,51% de plus production de biométhane. Un CSTR à deux étages avec digestat re-circulation de meilleurs résultats que d'un stade en raison de sa (i) une meilleure capacité d'auto-ajustement du pH; (ii) une plus grande résistance aux chocs de charge organique; (iii) de près de 100% de matières solides volatiles a été destryoed par rapport à 71% en CSTR une étape; (iv) 50 à 60% de teneur en méthane a été obtenu, alors qu'il était de 40 à 50% en une seule étape CSTR; (c) une petite quantité d'hydrogène a également été détectée à partir de la première étape du réacteur à deux étages qui en fait un système attrayant pour la production de biohythane. Bien que la séparation physique des méthanogènes rendus plus sensibles à des facteurs inhibiteurs, tels que l'ammonium et l'acide propionique. En outre, le temps de rétention hydraulique (HRT) est encore une chute de ces systèmes, d'où une AnMBR équipé d'une membrane de fluorure de vinylidène courant latéral a été proposé et exploité avec succès pour 100 d. Merci de membranes HRT a pu être réduite de 20 d à 1d, tout en conservant un rendement global d'élimination de> 97% de la demande en oxygène influent chimique (COD) et a abouti à une production de biogaz supérieure à 70% de teneur en méthaneTreatment of food waste by anaerobic digestion can lead to an energy production coupled to a reduction of the volume and greenhouse gas emissions from this waste type. Nevertheless, obtaining the highest possible methane recovery in a shorter time with a stable operation is challenging. To overcome the hurdles of AD of FW various pretreatment methods, supplementation of trace elements, bioaugmentation using zoo animals' dung and comparison of reactor configurations including one-stage and two-stage continuously stirred tank reactors (CSTR) as well as anaerobic membrane reactor (AnMBR) were studied in the scope of this research. Based on the results of the batch experiments, thermal pretreatment at 80°C for 1.5 hours yielded 46 – 52% higher biomethane production, and it is more energy efficient than ozonation or thermophilic shock pretreatments. Among the various tested concentrations and trace elements Fe (II) and Se (VI) concentrations of 25-50 ug/L resulted in 39 and 35% increase of biomethane production, respectively. A better solubilization of proteins (6.96 ± 2.76% more) and recalcitrant carbohydrates (344.85 ± 54.31 mg/L as compared to zero) could be obtained with bioaugmentation of giraffe dung (30% by volume), which yielded a 11.24 ± 4.51% higher biomethane production. A two-stage CSTR with digestate re-circulation performed better than one-stage with (i) a better pH self-adjusting capacity; (ii) a higher resistance to organic loading shocks; (iii) almost 100% volatile solids was destroyed as compared to 71% in one-stage CSTR; (iv) 50-60% methane content was obtained, while it was 40-50% in one-stage CSTR; (v) a small amount of hydrogen was also detected from the first stage of the two-stage reactor making it an attractive biohythane production system. Although physically separating the methanogens made them more sensitive to inhibitory factors, such as ammonium and propionic acid. Moreover, the long hydraulic retention time (HRT) is still the problem with these systems, hence an AnMBR equipped with a side-stream polyvinylidene fluoride membrane was proposed and a successful operation was achieved. Thanks to the membranes the HRT was able to be reduced from 20 d to 1d, while maintaining an overall removal efficiency of >97% of the influent chemical oxygen demand (COD) and yielded a higher biogas production with 70% methane content
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Yeshanew, Martha Minale. "Amélioration des rendements de traitement des déchets par digestion anaérobie : rôle d'un pré-traitement thermique et d'un traitement en bioréacteur en deux étapes." Thesis, Paris Est, 2016. http://www.theses.fr/2016PESC1166.
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La digestion anaérobie est utilisée depuis près d’un siècle comme un traitement efficace des déchets organiques. L’intérêt de ce traitement en anaérobie est en essor, car il présente des avantages significatifs sur les traitements alternatifs biologiques et d’autres options d’élimination des déchets. Cette étude se focalise sur l’optimisation du processus de digestion anaérobie en utilisant deux stratégies différentes. La première vise à augmenter la biodégradabilité du substrat par un prétraitement thermique. La seconde technique repose sur l’utilisation d’un système de biofilms pour augmenter le taux de production de biogaz et minimiser la taille du réacteur.Les déchets alimentaires sont principalement utilisés comme substrat modèle de par leur composition, leur abondance et leur renouvellement. Dans ces travaux de thèse, l’influence de la température des prétraitements thermiques sur la solubilisation de la matière organique, ainsi que la production de méthane des déchets alimentaires sous différentes conditions ont été étudié. Une amélioration significative de la solubilisation et de la biodégradabilité des déchets alimentaires ont été observés pour tous les prétraitements thermiques sur les déchets alimentaires comparativement aux déchets non traités. La plus importante amélioration (28%) de la biodégradabilité a été observée pour les déchets alimentaires traités à la plus basse température de prétraitements (80°C). Les résultats montrent une corrélation forte entre le type de substrats (carbohydrate, protéines et teneur en lipides), la température de prétraitement thermique et son efficacité dans l’amélioration de la biodégradabilité.Dans une seconde partie, une opération prolongée d’un système intégré à deux étages, incluant une cuve agitée en continu et un réacteur à biofilm anaérobie a été réalisé pour produire du biohytane (biohydrogène et méthane) à partir de déchets alimentaires. Le réacteur à biofilm anaérobie a été utilisé pour remédier au lessivage de la biomasse du réacteur. La formation d’une biomasse mature et équilibrée a amélioré de façon importante la stabilité du processus, ce dernier n’ayant pas été affecté par un raccourcissement du temps de rétention hydraulique (HRT) de 6 à 3,7 jours dans le premier réacteur, et de 20 à 1,5 jours dans le second réacteur. De plus, le système à deux étages, constitué d’un pilote à l’échelle d’un batch pour la fermentation sombre et d’un réacteur à biofilm anaérobie, coproduisant de l’hydrogène et du méthane à partir de la fraction organique des déchets solide ménagers (OFMSW), a été utilisé afin de déterminer la capacité d’un réacteur à biofilm anaérobie à supporter un choc de charge organique. Les résultats montrent une récupération plus rapide du réacteur à biofilm anaérobie après un évènement de charge organiqueAnaerobic digestion (AD) has been used over a century for an effective treatment of organic wastes. Interest in anaerobic treatment is continually increasing since it presents significant advantages when compared to alternative biological treatments and waste disposal options. This research study was mainly focused on optimization of the AD process, that was achieved through two different strategies. The first aimed at increasing the substrate biodegradability by a means of thermal pretreatment. The second was focused on the application of a biofilm based system to improve the biogas production rates and minimize the reactor size.Food waste (FW) was mainly used as a model substrate due to its suitable composition, abundance and renewability. In this thesis the influence of thermal pretreatment temperature on organic matter solubilization and methane yield of FW under different operational conditions was investigated. Significant improvement of the FW solubilization and biodegradability were observed for all thermally pretreated FW compared to the untreated FW. The highest biodegradability enhancement, i.e. + 28 %, was observed for FW treated at the lowest thermal pretreatment temperature, i.e. 80 ⁰C. The results showed a strong correlation between the substrate type (e.g. carbohydrate, protein and lipid content), the thermal pretreatment temperature and its effectiveness in promoting the biodegradability.In the second part of the work, a prolonged operation of an integrated two-stage system, including a continuously stirred tank and an anaerobic biofilm reactor, was carried out to produce biohythane (biohydrogen and methane) from the FW. The anaerobic biofilm reactor was employed to overcome the biomass wash-out from the reactor. The formation of a well-matured and balanced AD biomass greatly improved the process stability, which was not affected by shortening the hydraulic retention time (HRT) from 6 to 3.7 days in the first reactor and from 20 to 1.5 days in the second reactor. Moreover a two-stage system, comprised of a pilot scale batch dark fermenter and an anaerobic biofilm reactor co-producing hydrogen and methane from the organic fraction of municipal solid waste (OFMSW), was used to assess the capability of the anaerobic biofilm reactor to face an organic shock loads. The results showed a faster recovery of anaerobic biofilm reactor performance after the shock load events
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Ramos, Elsa Dolores Chacin. "Treatment characteristics of two phase anaerobic system using an UASB reactor." Thesis, University of Birmingham, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.633074.
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During this project, the treatment of a simulated wastewater from soluble starch by a two-phase anaerobic system using an UASB reactor was examined under mesophilic conditions. Prior to seeding the reactors, the pregranulated sludge which was to be used as the inoculum for the acidogenic reactor, was acidified to pH 4.3, using a mixture of volatile fatty acids, to improve the spatial bacteria separation in the system. The two-phase system was studied, first under different organic loads and secondly, in terms of its resistance to the addition of heavy metals. For the first experimetal studies, different organic load were applied to the system, and changes to the microbial ecology of the acidogenic and the methanogenic phase was assessed. The biomass in the methanogenic reactor was mainly composed of fluorescent methanogenic bacteria. In the acidogenic reactor after the start-up period elapsed, no fluorescent bacteria were observed. Two different runs were performed and for each individual run, different OLR were used. For the first run, the organic loads applied to the system were from 3.83 to 30.63 kg COD/m3d, this gave organic loads for the methanogenic reactor of between 4.56 to 44.3 kg COD/m3d. In the second run, the OLR used were from 10 to 16.6 kg COD/m3d for the overall system, and from 13 to 23.35 kg COD/m3d for the methanogenic reactor. Organic loads greater than 15 kg COD/m3d, caused biomass wash-out from both the acidogenic and methanogenic reactor. The best COD removal efficiencies and gas production rates were achieved by the system under OLR of 13.31 kg COD/m3d, with pCOD removal efficiency of 95 % and methane production of 80.2 %. The biogas production was 0.33 m3CH4/kg COD removed. Under high applied organic load, the microbial population of the methanogenic reactor changed, and filamentous foaming bacteria were isolated both from the sludge and the foam that was produced. The species found to be responsible for the foam formation in the anaerobic methanogenic reactor was Microthrix parvicella, which was identified using the Neisser test and Scanning Electron Microscopy (SEM). For the second part of this experimental work, copper and lead were used as toxic elements. These two heavy metals were choose due to the fact that they are subproducts of many industries and can cause significant environmental problems. Copper and lead were used as the acetates and chlorides to study the effect of these heavy metals when they were combined with different anions. It was found that the combination of copper and lead as chlorides were more toxic to the anaerobic treatment than when they were present as acetate. Also, it was found that the two heavy metals used were toxic to the acidogenic phase and not to the methanogenic phase.
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Chelliapan, Shreeshivadasan. "Treatment of pharmaceutical wastewater containing macrolide antibiotics by Up-Flow Anaerobic Stage Reactor (UASR)." Thesis, University of Newcastle Upon Tyne, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.427280.
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Stampfli, John J. "Design of a two-stage multi-state experimental biogas reactor." Thesis, Massachusetts Institute of Technology, 2020. https://hdl.handle.net/1721.1/127871.
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Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, May, 2020Cataloged from the official PDF of thesis.
Includes bibliographical references (pages 23-25).
Anaerobic digestion is a process that breaks down waste and other feed materials and produces biogas. A biogas reactor, or anaerobic digester, is designed to conduct anaerobic digestion in a closed environment and to collect the produced biogas. This is an important field of study because biogas is a renewable energy source. If it can be produced more efficiently, it may become a feasible alternative source of green energy. This thesis outlines the design of a lab-scale experimental reactor with a large range of functionality. The design permits many different environmental conditions, allowing anaerobic digestion to be thoroughly studied with one setup.
by John J. Stampfli.
S.B.
S.B. Massachusetts Institute of Technology, Department of Mechanical Engineering
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Magnusson, Björn. "Evaluation of pre-fermentation using confectionery waste products for two-stage anaerobic digestion." Thesis, Linköpings universitet, Tema vatten i natur och samhälle, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-57469.
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The finite amount of energy carriers affects all of us. It is important to utilize all available sources and to find new sources of energy. The confectionery industry generates both solid and liquid waste during the production of confectioneries, which could be utilized as a substrate for biogas production. However, problems might arise during the biogas process since these kinds of waste are very rich in carbohydrates. The initial breakdown of the substrate would probably cause an accumulation of fermentation products such as volatile fatty acids (VFA) and a low pH. A solution to this might be to use a two-stage process. The first stage would be a pre-fermentation that should be optimized for production of fermentation products such as ethanol and VFA. The aim of this master thesis is to evaluate the biogas potential of confectionery waste products. The confectionery waste products are evaluated using a continuous two-stage process, batch experiments and theoretical calculations of the methane potential. The potential from process wastewater was examined. Depending on COD reduction for a reactor and COD content of process wastewater, an annual amount of 75 000 m3 or of 857 000 m3 of process wastewater is necessary to produce enough biogas for a gas engine to continuously convert the biogas to electricity. A batch experiment evaluating the methane production potential of nine different confectionery waste products from a large confectionery industry gave a range of 430 - 690 NmL/g VS, which is relatively high. A continuous experiment in two lab-scale reactors with a HRT of two days worked satisfactory. The gas production was stable periodically with a carbon dioxide content above 60%. The pH was low (3.4 - 3.6) throughout the experiment for one of the reactors. However, addition of digester sludge from a methane-producing reactor towards the end of the experiment resulted in a higher pH and more VFA available for utilization in the second stage. The main fermentation products were: acetic acid, lactic acid, ethanol and carbon dioxide. A second batch experiment showed that the methane potential was not affected by pre-fermentation. A carbon balance calculation of the process indicates that 57% of the ingoing organic matter is fermented within only two days and ends up in the known fermentation products. The study shows that confectionery waste products are well suited for two-stage anaerobic digestion.Den ändliga mängden av energibärare påverkar oss alla. Det är därför viktigt att utnyttja alla tillgängliga men även att finna nya energibärare. Konfektyrindustrin generar restprodukter (avfall) både i fast och flytande form, vilka båda kan utnyttjas för produktion av biogas. Det kan dock uppstå problem i biogasprocessen eftersom dessa innehåller en stor mängd kolhydrater. Den initiala nedbrytningen kan ge upphov till en ackumulering av VFA och ett lågt pH. En lösning på detta problem kan vara att använda en två-stegs process. Första steget är en för-fermentering, som ska optimeras för att producera fermentationsprodukter så som etanol och VFA. Syftet med detta arbete är att utvärdera biogaspotentialen från konfektyrrestprodukter genom att använda en kontinuerlig två-stegs process, batchförsök och teoretiska beräkningar av metanpotentialen. Potentialen undersöktes från processvatten. Beroende på COD reduktion i en reaktor och COD innehåll i processvatten, är en årlig mängd av 75 000 m3 eller av 857 000 m3 processvatten nödvändig för att producera en tillräcklig mängd biogas så att en gasmotor kontinuerligt kan omvandla biogasen till elektricitet. Ett batchförsök med nio olika restprodukter från en storskalig konfektyrproducent visade en relativt hög metanpotential (430 - 690 NmL/g VS). Ett kontinuerligt reaktorexperiment genomfördes i laboratorieskala med två reaktorer, där uppehållstiden var två dagar. De två för-fermenteringsreaktorerna presterade tillfredsställande. Gasproduktionen var periodvis stabil med en koldioxidhalt över 60%. pH var lågt (3,4 och 3,6) genom hela experimentet för en av reaktorerna. För den andra reaktorn gjordes tillsatser av reaktormaterial från en metanproducerande reaktor i slutet av experimentet. Dessa tillsatser ökade pH och totalmängden av VFA, som kan utnyttjas i det andra steget. Huvudfermentationsprodukterna är acetat, laktat, etanol och koldioxid. Ytterligare batchförsök visade att för-fermentation inte verkar påverka metanpotentialen för konfektyrrestprodukter. En kolbalans av processen indikerar att 57% av ingående kol återfinns i de kända fermentationsprodukterna inom två dagar. Studiens resultat visar att avfallsprodukter från konfektyrindustrin lämpar sig väl för två-stegs anaerob rötning.
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Kitsos, Haralambos Minas. "Development of a two-stage immobilized cell bioreactor for the production of methane from organic wastes." Diss., Georgia Institute of Technology, 1989. http://hdl.handle.net/1853/11796.
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Merkle, Wolfgang [Verfasser], and Thomas [Akademischer Betreuer] Jungbluth. "Two-stage high pressure anaerobic digestion for biomethane production / Wolfgang Merkle ; Betreuer: Thomas Jungbluth." Hohenheim : Kommunikations-, Informations- und Medienzentrum der Universität Hohenheim, 2017. http://d-nb.info/1141790173/34.
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Wang, Zhengjian. "Evaluation of a two stage anaerobic digestion system for the treatment of mixed abattoir wastes." Thesis, University of Manchester, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.561416.
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McDougall, Forbes Russell. "Optimization and evaluation of the acidification stage of a two-phase anaerobic digester treating coffee wastewater." Thesis, University of Newcastle Upon Tyne, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.318254.
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Thompson, Reese S. "Hydrogen Production By Anaerobic Fermentation Using Agricultural and Food Processing Wastes Utilizing a Two-Stage Digestion System." DigitalCommons@USU, 2008. https://digitalcommons.usu.edu/etd/208.
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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.
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Pathak, Ankit Bidhan. "Two - Stage AnMBR for Removal of UV Quenching Organic Carbon from Landfill Leachates: Feasibility and Microbial Community Analyses." Diss., Virginia Tech, 2017. http://hdl.handle.net/10919/84514.
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Landfilling is the most widely used method for the disposal of municipal solid wastes (MSW) in the United States due to its simplicity and low cost. According to the 2014 report on Advancing Sustainable Materials Management by the USEPA, only 34% of the total MSW generated in the US was recycled, while 13% was combusted for energy recovery. In 2014, 53% of the MSW generated, (i.e. 136 million tons) in the US was landfilled. The treatment of landfill leachates, generated by percolation of water through the landfill, primarily due to precipitation, has been found to be one of the major challenges associated with landfill operation and management. Currently, leachates from most landfills are discharged into wastewater treatment plants, where they get treated along with domestic sewage.
Issues associated with treatment of landfill leachates due to their high nitrogen and heavy metal content have been widely studied. Recently, it has been observed that the organic carbon in landfill leachates, specifically humic and fulvic acids (together referred to as "humic substances") contain aromatic groups that can absorb large amounts of ultraviolet (UV) light, greatly reducing the UV transmissivity in wastewater plants using UV disinfection as the final treatment step. This interference with UV disinfection is observed even when landfill leachates constitute a very small fraction (of the order of 1%) of the total volumetric flow into wastewater treatment plants. Humic substances are present as dissolved organic matter (DOM) and typically show very low biodegradability. Removing these substances using chemical treatment or membrane processes is an expensive proposition. However, the concentrations of humic substances are found to be reduced in leachates from landfill cells that have aged for several years, suggesting that these substances may be degraded under the conditions of long-term landfilling.
The primary objective of this research was to use a two-stage process employing thermophilic pretreatment followed by a mesophilic anaerobic membrane bioreactor (AnMBR) to mimic the conditions of long-term landfilling. The AnMBR was designed to keep biomass inside the reactor and accelerate degradation of biologically recalcitrant organic carbon such as humic substances. The treatment goal was to reduce UV absorbance in raw landfill leachates, potentially providing landfills with an innovative on-site biological treatment option prior to discharging leachates into wastewater treatment plants. The system was operated over 14 months, during which time over 50% of UV-quenching organic carbon and 45% of UV absorbance was consistently removed. To the best of our knowledge, these removal values are higher than any reported using biological treatment in the literature. Comparative studies were also performed to evaluate the performance of this system in treating young leachates versus aged leachates.
Next-generation DNA sequencing and quantitative PCR (qPCR) were used to characterize the microbial community in raw landfill leachates and the bioreactors treating landfill leachate. Analysis of microbial community structure and function revealed the presence of known degraders of humic substances in raw as well as treated landfill leachates. The total number of organisms in the bioreactors were found to be higher than in raw leachate. Gene markers corresponding to pathogenic bacteria and a variety of antibiotic resistance genes (ARGs) were detected in raw landfill leachates and the also in the reactors treating leachate, which makes it necessary to compare these ARG levels with wastewater treatment in order to determine if leachates can act as sources of ARG addition into wastewater treatment plants. In addition, the high UV absorbance of leachates could hinder the removal of ARBs and ARGs by UV disinfection, allowing their release into surface water bodies and aiding their proliferation in natural and engineered systems.Ph. D.
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Dastidar, Aniruddha. "ARSENITE OXIDATION BY PURE CULTURES OF THIOMONAS ARSENIVORANS STRAIN B6 IN BIOREACTOR SYSTEMS." UKnowledge, 2010. http://uknowledge.uky.edu/gradschool_diss/70.
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The removal of arsenic toxicity from water is accomplished by a preliminary preoxidative step transforming the most toxic form, arsenite (As (III)), to the least toxic form, arsenate (As (V)). The potential of As (III) oxidation to As (V) was initially investigated in batch reactors using the chemoautotrophic Thiomonas arsenivorans strain b6 under varying initial As (III) and cell concentrations and at optimal pH and temperature conditions (pH 6.0 and temperature 30°C). The strain b6 completely oxidized As (III) to As (V) during exponential growth phase for lower levels of As (III) concentrations (≤ 100 mg/L) but continued into stationary phase of growth for higher levels (≥ 500 mg/L). Other important factors such as oxygen and carbon limitations during biological As (III) oxidation were also evaluated. The biokinetic parameters of the strain b6 were estimated using a Haldanesubstrate inhibition model with the aid of a non-linear estimation technique.
Microbial As (III) oxidation was further investigated in continuous-flow bioreactors (CSTR and biofilm reactor) under varying As (III) loading rates. Both the reactors achieved As (III) oxidation efficiency exceeding 99% during the steady-state conditions. The reactors were also able to recover from an As (III) overloading phase establishing the resilient nature of the microorganism. The basic mass balance expressions on As (III) and biomass along with the Monod model were used to linearly estimate the biokinetic parameters in the CSTR study. However, in the biofilm study, a steady-state flux model was used to estimate the same parameters. The performance of the model was very good in simulating the transient and steady-state conditions.
Finally, the potential application of one-stage and two-stage reactor systems was investigated for the near complete removal of arsenic. Activated alumina was used as the adsorbent for the As (V) produced by the biological oxidation of As (III). The two-stage reactor process performed better than the one-stage reactor system in lowering the arsenic level below the detection limit (1 mg/L) for at least eight days of operation. However, pH fluctuations and probable competition from ions such as PO43- , SO42-, and Cl- severely impacted the performance of the reactors. Further study is needed to improve the overall efficiency of the reactor systems for achieving complete removal of arsenic for a longer operating time.
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Bryant, Isaac Mbir [Verfasser], and Marion [Gutachter] Martienssen. "Development of single-stage solar-supported hyper-thermophilic anaerobic reactor for biogas production and disinfection of black water : a pilot case study of Terterkessim slum, Elmina – Ghana / Isaac Mbir Bryant ; Gutachter: Marion Martienssen." Cottbus : BTU Cottbus - Senftenberg, 2019. http://d-nb.info/1182993583/34.
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Aslanzadeh, Solmaz. "Pretreatment of cellulosic waste and high rate biogas production." Doctoral thesis, Högskolan i Borås, Institutionen Ingenjörshögskolan, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-3684.
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The application of anaerobic digestion technology is growing worldwide, mainly because of its environmental benefits. Nevertheless, anaerobic degradation is a rather slow and sensitive process. One of the reasons is the recalcitrance nature of certain fractions of the substrate (e.g., lignocelluloses) used for microbial degradation; thus, the hydrolysis becomes the rate-limiting step. The other reason is that the degradation of organic matter is based on a highly dynamic, multi-step process of physicochemical and biochemical reactions. The reactions take place in a sequential and parallel way under symbiotic interrelation of a variety of anaerobic microorganisms, which all together make the process sensitive. The first stage of the decomposition of the organic matter is performed by fast growing (hydrolytic and acid forming) microorganisms, while in the second stage the organic acids produced are metabolized by the slow growing methanogens, which are more sensitive than the acidogens; thus, methanogenesis becomes the rate-limiting step. The first part of this work evaluates the effects of a pretreatment using an organic solvent, N-methylmorpholine-N-oxide (NMMO), on cellulose-based materials in order to overcome the challenge of biomass recalcitrance and to increase the rate of the hydrolysis. NMMO-pretreatment of straw separated from the cattle and horse manure resulted in increased methane yields, by 53% and 51%, respectively, in batch digestion tests. The same kind of pretreatment of the forest residues led to an increase by 141% in the methane production during the following batch digestion assays. The second part of this work evaluates the efficacy of a two-stage process to overcome the second challenge with methanogenesis as the rate-limiting step, by using CSTR (continuous stirred tank reactors) and UASB (up flow anaerobic sludge blanket) on a wide variety of different waste fractions in order to decrease the time needed for the digestion process. In the two-stage semi-continuous process, the NMMO-pretreatment of jeans increased the biogas yield due to a more efficient hydrolysis compared to that of the untreated jeans. The results indicated that a higher organic loading rate (OLR) and a lower retention time could be achieved if the material was easily degradable. Comparing the two-stage and the single-stage process, treating the municipal solid waste (MSW) and waste from several food processing industries (FPW), showed that the OLR could be increased from 2 gVS/l/d to 10 gVS/l /d, and at the same time the HRT could be decreased from 10 to 3 days, which is a significant improvement that could be beneficial from an industrial point of view. The conventional single stage, on the other hand, could only handle an OLR of 3 gVS/l/d and HRT of 7 days.
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Knoop, Christine [Verfasser], Thomas [Gutachter] Raab, and Christina [Gutachter] Dornack. "Anaerobic treatment of municipal organic waste from separate collection : digestate properties and substance flows during two-stage digestion and subsequent aerobic treatment / Christine Knoop ; Gutachter: Thomas Raab, Christina Dornack." Cottbus : BTU Cottbus - Senftenberg, 2019. http://d-nb.info/1185489894/34.
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Rajendran, Karthik, and Gopinath Balasubramanian. "High rate biogas production from waste textiles." Thesis, Högskolan i Borås, Institutionen Ingenjörshögskolan, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-20787.
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Textile is a global product used by all people in the world. These textiles after the use are thrown into the trash for incineration or land filling. However an efficient way that can be used to produce more energy, in an environmentally friendly process is anaerobic digestion. Waste textiles which contain cellulosic fibers (e.g. Cotton and viscose) can be converted to biogas. In this study, the performance of a two-stage anaerobic digestion process for biogas production from four different materials, including untreated jeans, treated jeans, cotton, and starch was studied. Starch was used as an easy-to-digest material to compare its digestion with that of cellulosic materials.The two-stage processes were composed of a CSTR (for hydrolysis) and a UASB (for methanogenisis) which were investigated in two different configurations, namely (closed and open systems). In the closed system, the outlet of UASB was completely returned back to the CSTR, while in the open system the UASB outlet was sent to sewage. In a stepwise progress, the OLR was aimed to increase from 2 to 20 g Vs per L per day along with reduction in hydraulic retention time from 10 days to 1 day.The results showed that the closed system was more stable when compared to the open system. The pre-treatment of jeans by NMMO helped to produce methane as that of cotton. The hydraulic retention time was decreased to less than 9 days for treated jeans and less than 5 days for starch. The overall methane yield at OLR of 4 gVS per L per day for starch and treated jeans was 98.5% and 97.4% in the closed system, whereas in the open system the yield was 77.0% and 35.5%, respectively.Another experiment was conducted to compare the performance of two-stage process with that of a single stage process of anaerobic digestion of textiles containing polyester and cotton or viscose. Viscose textiles produced more gas compared to the cotton textile; it may be due to the higher crystalline of cotton which makes it hard to be degraded by the microorganisms. Furthermore, two-stage process could able to produce more methane than the single stage process.The parameters like total solids, volatile solids, pH, gas production, gas composition, concentration of nutrients, and COD were also analyzed for both of the experiments.
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Bethune, Kristie Joyce Chamber Robert P. "Bioremediation of pentachlorophenol and bleach plant effluent by Trametes versicolor and its extracellular fluid, focused on intermediates and products formed and the role of protein binding of chlorinated compounds in a two-stage reactor system." Auburn, Ala., 2005. http://repo.lib.auburn.edu/2005%20Summer/doctoral/BETHUNE_KRISTIE_56.pdf.
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Dillenburg, Marcelo Elias. "Variação da taxa de recirculação de lixiviado determinada pela concentração de ácidos voláteis no tratamento da fração orgânica de resíduos sólidos urbanos domésticos." Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/18/18138/tde-19122006-144627/.
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O objetivo deste trabalho foi avaliar a possibilidade de acelerar o processo de digestão anaeróbia da fração orgânica de resíduos sólidos urbanos domésticos em sistemas de duas fases, com taxas crescentes de recirculação de lixiviado, variando a taxa de recirculação de lixiviado em função da concentração de ácidos voláteis. Para tanto, foram operados dois sistemas de reatores, cada um composto por um reator de sólidos, que continha o resíduo sólido a ser tratado e um filtro anaeróbio de fluxo ascendente, que tratava o lixiviado do primeiro, antes que esse lixiviado fosse recirculado ao reator de sólidos. Um dos sistemas teve sua taxa de recirculação aumentada a intervalos constantes, enquanto que no outro o momento do aumento da taxa foi função da concentração de ácido propiônico no sistema. O trabalho teve ainda dois objetivos secundários: avaliar a validade de comparar os resultados dos dois sistemas, operados em paralelo, em função das características dos resíduos sólidos e dos procedimentos adotados para coleta e preparação do substrato e para o carregamento dos reatores; e avaliou-se a possibilidade de utilizar filtros anaeróbios para recuperar reatores acidificados. Durante o desenvolvimento do experimento, foram monitorados os seguintes parâmetros: DQO (não filtrada e filtrada), pH, alcalinidade, série de sólidos, nitrogênio total Kjeldahl, nitrogênio amoniacal, ácidos voláteis e composição do biogás. Foram realizados ainda exames qualitativos da microbiota que se desenvolveu nos reatores, através de microscopia óptica de fluorescência e contraste de fase. Os resultados obtidos permitiram concluir que: a) os procedimentos testados para o carregamento dos reatores de sólidos permitiram a comparação de resultados entre os sistemas; b) os filtros foram capazes de recuperar reatores acidificados; e c) a utilização da concentração de ácido propiônico para determinar o momento da variação da taxa de recirculação permitiu acelerar o processo, embora de forma restrita, para a escala de reatores utilizada.The purpose of this dissertation was to evaluate the possibility of accelerating the process of anaerobic digestion of the organic fraction of domestic municipal solid waste, in two-stage systems, with increasing leachate recirculation rate, through the use of volatile acids as determining parameter of the moment in which the rate must be varied. To do so, two systems of reactors were operated, each being composed by a solids reactor, which contained the solid waste intended to be treated, and an upflow anaerobic filter, which treated the leachate of the first reactor, before recirculation. One of the systems had its recirculation rate increased at constant spells of time, while, in the other system, the moment of the increase in the recirculation rate was a function of the concentration of propionic acid in the system. This study had yet two secondary purposes: evaluating the validity of comparing the results from the two systems of reactors, operated in parallel, in view of the characteristics of solid waste and the adopted procedures for collecting and preparing the substrate, as well as for the loading of reactors; and evaluating the possibility of using anaerobic filters to recover acidified reactors. The following parameters were measured during the process: COD (filtered and non-filtered), pH, alkalinity, solids, Kjeldahl nitrogen, ammonium nitrogen, volatile acids and biogas composition. The development of microorganisms in the reactors was observed qualitatively, using optical microscopy. It was possible to reach the following conclusions: a) the tested procedures allow the comparison of results between the systems; b) the filters are capable of recovering acidified reactors; and c) the employment of the concentration of propionic acid to determine the moment of increase of leachate recirculation rate is capable of accelerating the process, though in a restricted way, for the scale of reactors used.
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Barboza, Marcio Gomes. "Efeitos da temperatura e velocidade superficial em sistema anaeróbio de duas fases tratando esgoto sanitário sintético em reatores horizontais com células imobilizadas." Universidade de São Paulo, 2002. http://www.teses.usp.br/teses/disponiveis/18/18138/tde-24112016-145350/.
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Este trabalho investigou o efeito da temperatura nos sistemas aneróbios com células imobilizadas tendo como estudo de caso um sistema anaeróbio em duas fases. Inicialmente, foram realizados experimentos preliminares com um sistema em duas fases composto por Reator Acidogênico Horizontal Tubular (RAHT) seguido de Reator Anaeróbio Horizontal de Leito Fixo (RAHLF), nas temperaturas de 15ºC, 20ºC e 25ºC. Os resultados mostraram que o RAHT alcançou 48% de remoção de DQO e que a desvantagem da ausência de microrganismos consumidores de H2 no sistema praticamente não afetou a produção de ácido acético. Pôde-se observar que na faixa de temperatura estudada o RAHT não apresentou mudanças significativas em seu desempenho. Posteriormente foram realizados experimentos com cinco reatores metanogênicos do tipo RAHLF, alimentados com esgoto sintético simulando o efluente do RAHT, com velocidades de 10,4 cm/h, a 52,0 cm/h e temperatura de 15ºC a 35ºC. Os resultados permitiriam o desenvolvimento de um modelo empírico-estatístico para simulação do desempenho dos reatores, tendo como variáveis a velocidade superficial do líquido sobre as biopartículas e a temperatura de operação. Os resultados preditos pelo modelo demonstraram boa representatividade dos valores experimentais. Com isso, foi possível observar as influências da velocidade superficial (vs) e da temperatura, nas concentrações residuais de substrato (Sr) e nas constantes cinéticas aparentes de primeira ordem (K1app). Conclui-se então, que apesar do aumento de vs resultar em maiores valores de K1app, também foi observado aumento no valor de Sr indicando que existe um tempo de contato mínimo entre os microrganismos e o substrato.The effects of temperature and superficial velocity in an anaerobic methanogenic immobilized cell rector of a two phase-system were investigated. Preliminarily, a Tubular Horizontal Acidogenic Reactor (THAR) followed by Horizontal-flow Anaerobic Immobilized Biomass (HAIB) composed the experimental system, operated at the temperatures of 15°C, 20°C and 25°C. COD removal efficiency of 48% was observed in the THAR. Likewise, the disadvantage of the absence of H2-consumer methanogenics microorganisms in the system almost did not affect the production of acetic acid. The temperature variation has not caused significant changes in the THAR performance. The next step was the development of experiments using five methanogenics HAIB reactors fed on synthetic wastewater simulating THAR effluent having superficial velocities from 10,4 cm/h to 52,0 cm/h and temperature from 15°C to 35°C. The results enabled the development of a statistical-empiric modeling to simulate the reactors performance using the liquid superficial velocities and the temperature operation as model variables. The model demonstrated a good agreement with the experimental values. The influence of the superficial velocities (vs) and temperature, in the substrate residual concentration (Sr) and in the first order (K1app) apparent kinetic constant was observed. Despite the K1app values have increased largely with vs, the Sr concentration also increased. These results permit to conclude that a minimum contact time between the microorganisms and the substrate may be necessary in such processes.
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Vilela, Rogerio Silveira. "Produção de hidrogênio e metano a partir de subproduto da indústria sucroalcooleira, em reatores anaeróbios de fases separadas sob condição termofílica." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/18/18138/tde-18042017-110703/.
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A digestão anaeróbia tem se apresentado como um processo de grande interesse sob a ótica da potencial produção de energia renovável (H2 e CH4), considerando-se a ampla variedade de compostos orgânicos que podem ser utilizados. Neste estudo desejou-se avançar na compreensão do sistema de reatores anaeróbios de duas fases (acidogênico seguido de metanogênico) operados em condições termofílicas (55°C), alimentados com melaço da cana-de-açúcar, subproduto da indústria sucroalcooleira. Os experimentos foram conduzidos em reatores anaeróbios de leito fixo estruturado com fluxo ascendente e o melaço foi diluído com água de abastecimento, para adequação da concentração aos processos de tratamento de águas residuárias. Na 1ª Etapa dois reatores acidogênicos foram operados em paralelo para avaliar diferentes formas de inoculação e meios suportes, a fim de manter a produção continua e estável de hidrogênio. Para isso foram aplicadas diferentes cargas orgânicas (2,5, 5 e 10 gDQO.L-1) que resultam em COV de 30, 60 e 120 g.DQO.Lreator1.dia-1, com TDH fixo de 2 horas. A expressão do gene hidrogenase foi detectado em ambos os reatores, mas em maior proporção no reator inoculado com lodo de reator UASB e usando como material suporte a espuma de poliuretano. Sequencialmente a este reator, foi acoplado um reator metanogênico, alimentado com efluente do reator acidogênico, estabilizado nas condições apresentadas, e operado com COV crescentes de 1, 2, 5, 7, 14, 17 e 26,5 gDQO.Lreator-1.dia-1 e consequente diminuição do TDH de 240, 96, 48, 32, 24, 16 e 12 horas. O reator acidogênico na 2ª etapa foi operado por 417 dias consecutivos e COV de 120 g.DQO.Lreator1.dia-1, produzindo hidrogênio continuamente, alcançado valores de produção bruta de H2 de 7,60 LH2.dia-1. O reator metanogênico foi operado por 251 dias consecutivos, produzindo metano e alcançado valores de produção bruta de CH4 de 5,90 LCH4.dia-1. A eficiência de remoção de DQO do sistema de reatores foi de aproximadamente 90%, com contribuição aproximadamente de 10% para o reator acidogênico e contribuição aproximadamente de 80% para o reator metanogênico. O reator acidogênico alcançou rendimento de produção de hidrogênio por kg de melaço aplicado de 392 LH2.kgmelaço-1 e o reator metanogênico de 387 LCH4.kgmelaço-1. Para finalidade de comparações e aplicabilidade, o ganho energético global do sistema de reatores de duas fases foi de aproximadamente 5,7 kWh.kgmelaço-1 (1,4 kWh.kgmelaço-1 para o reator acidogênico e 4,3 kWh.kgmelaço-1 para o reator metanogênico). A produção continua de H2 obtida neste estudo está relacionada à associação das vias dos ácidos produtores de hidrogênio já consolidados pela literatura pertinente (acético e butírico) e pela produção de hidrogênio pela rota do ácido lático, devido a associação entre as comunidades de microrganismos estabelecidas no reator. O sequenciamento massivo MiSeq mostrou a seleção de diversos gêneros de microrganismos com redundância funcional e pertencentes principalmente aos Filos Firmicutes, Proteobacteria e Thermotogae, tais como Clostridium sensu stricto, Thermohydrogenium, Thermoanaerobacterium e Cellulosibacter (Firmicutes); Pseudomonas, Enterobacter, Shewanella e Petrobacter (Proteobacteria) e Fervidobacterium (Thermotogae). Microrganismos produtores de ácido lático também foram selecionados tais como: Lactobacillus, Leuconostoc, Sporolactobacillus e Trichococcus. Dos pontos de vista científico e tecnológico este estudo deu mais um passo para a compreensão dos bioprocessos envolvidos nos sistemas anaeróbios em dois estágios produzindo H2 e CH4 continuamente por longo período de tempo.Anaerobic digestion has shown as an interesting process for renewable energy production (H2 and CH4), for a wide variety of organic compounds (carbon source). This study aimed to advance the understanding of a two-stage process anaerobic system (acidogenic bioreactor followed by methanogenic bioreactor) under thermophilic condition (55°C) fed with molasses, a sugarcane industry by-product. The experiments were conducted at up-flow structured bed reactors and sugarcane molasses was diluted with tap water, to adjust the concentration to the wastewater treatment. At first stage two acidogenic reactors were operated in parallel to evaluate different source of inocula and support bed, to obtain continuous and stable hydrogen production. It was applied 2.5, 5 and 10 gCOD.L-1 resulting in OLR of 30, 60 and 120 g.COD.Lreactor-1.day-1, with HRT fixed at 2 hours of hydrogenase gene was detected in both reactors but with higher number of copies of the gene in the reactor that showed higher hydrogen production: the reactor sed with sludge of UASB reactor and using polyurethane foam as support material. To this reactor was coupled a methanogenic reactor fed with effluent from acidogenic reactor and operated with increasing OLR (1, 2, 5, 7, 14, 17 e 26,5 gCOD.Lreactor-1.day-1) decreasing the HRT (240, 96, 48, 32, 24, 16 and 12 hours). The acidogenic reactor was operated during 471 days with OLR of 120 g.COD.Lreactor-1.day-1, with HRT fixed at 2 hours, with continuous hydrogen production with a gross production of 7.60 LH2.day-1. The methanogenic reactor was operated for 251 days, with continuous methane production of up to 5.90LCH4.day-1. The COD removal efficiency using the two-stage system was approximately 90% , with 10% contribution by the acidogenic reactor and 80% contribution by the methanogenic reactor. The acidogenic reactor achieved hydrogen yield per kg of applied molasses equal to 392 LH2.kgmolases-1. The methanogenic reactor achieved methane yield per kg of applied molasses equal to 387 LCH4.kgmolasses-1. For comparison and applicability purposes, the overall energy yield using the two stage reactor system was approximately 5.7 kWh.kgmolasses-1 (Acidogenic reactor 1.4 kWh.kgmolasses-1 and Methanogenic reactor 4.3 kWh.kgmolasses-1). The continuous production of H2 obtained in this study is related to the association of the hydrogen producer acids pathway established by the relevant literature (acetic and butyric) and the hydrogen production by the lactic acid pathway due to the microorganisms association established in the reactor. Metagenomic analysis by MiSeq Plataform revealed that hydrogen production was due the selection of microorganisms with functional redundancy mainly of Phyla Firmicutes, Proteobacteria and Thermotogae, such as Clostridium sensu stricto, Thermohydrogenium, Thermoanaerobacterium, Cellulosibacter (Firmicutes); Pseudomonas, Enterobacter, Shewanella and Petrobacter (Proteobacteria) and Fervidobacterium (Thermotogae). Genera of acid latic producers, such as Lactobacillus, Leuconostoc, Sporolactobacillus and Trichococcus, were also selected. From the scientific and technological point of view this study has taken another step towards the understanding of bioprocesses involving two stage anaerobic systems for a long term continuous production of H2 and CH4.
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LEE, CHUN-YI, and 李俊毅. "Comparison of Single-stage and Two-stage Anaerobic Digestion of Swine Wastewater." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/x5rv8p.
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碩士逢甲大學
綠色能源科技碩士學位學程
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The pig farms wastewater treatment were low in the efficiency of methane production due to unstable influent concentration, unstable wastewater volume or seasonal changes of wastewater quality. In this study, gravity sedimentation was utilized to pretreat and separate pig wastewater into three parts including raw wastewater (RW), settled sludge (SS) and supernatant liquid (SL). The methane production rate (MPR) values were 0.51, 0.59 and 0.13 L-CH4/L-d, for RW, SS and SL, respectively. Methane Yield (MY) was defined as methane produced from each gram of COD removed and the values were 0.23, 0.78 and 0.04 L-CH4/g-CODre for RW, SS and SL, respectively. The SS volume was reduced by 63% compared to the RW. These results indicate that the SS is more appropriate for methanogenesis. RSM experimental design method was used to investigate the operating conditions of acidification time and initial pH. The results indicate that MPR was 0.3 L-CH4/L-d at pH 6.5 and acidification time 1.5 days with volatile fatty acid 7 g-COD/L。 A continuously-feeding experiment was conducted to compare the capacity of single-stage and two-stage methane production. In the two-stage system, acid-producing phase had a volatile acid production of 5.5 g-COD/L with propionic and acetic acids accounting for approximately 50% in total. For methane concentration, the single-stage was 30% and the two-stage was 60%. The key to anaerobically ferment a wastewater containing high solid concentration is to control the rate of organic acid production. An excessive formation of organic acid would have an impact on gas production stability. The MPR of the single-stage and two-stage methane production were 0.04 and 0.09 mL-CH4/L-d, respectively. The microbial community structure analysis showed that the diversity of bacterial community for the two-stage was greater than that of the single-stage. The archaea (genus) was mainly Methanosarcina and Methanoculleus.
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Yu, Ching Lin Agatha. "Two-stage dry anaerobic digestion of municipal solid waste." 1992. http://hdl.handle.net/1993/18680.
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HSIAO, YU-TUNG, and 蕭羽廷. "Single and two-stage anaerobic fermentation of chicken manure." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/s7bf3d.
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碩士逢甲大學
環境工程與科學學系
106
Traditionally, chicken manure (CM) is treated by drying and compost. But this method is easy to cause secondary pollution problems. Unfermented chicken manure can cause disease-causing mosquito breeding once it comes into contact with water. Therefore, CM was anaerobically digested to reduce pollution and produce methane as energy. Methane is a kind of biogas. It is high relative abundance on Earth that cause it a fuel with great development potential. Batch test was conducted to obtain a proper acidogenesis’s time for two-stage fermentation to get peak methane production. One day was obtained as the proper acidogenesis’s time. Another test was to obtain a proper pH to get peak methane production in single- and two-stage fermentation. The results show that both fermentation systems had peak methane production at pH 7 with values of 684 mL and 439 mL, respectively. The optimal environmental factors got from the batch test were used in conducting continuously-feeding single-stage and two-stage anaerobic fermentation to produce methane. Hydraulic reaction time (HRT) was used as the operation parameter and showing that at HRT 30 days, single-stage methane reactor had the following results at steady state. Methane production rate (MPR) was 53.3 ± 25.3 mL/L. Methane yield was 29.5 ± 13 mL/g VS. Total chemical oxygen demand (TCOD) removal was 81 ± 8%. Volatile solids (VS) removal was 83 ± 9%. When HRT was fixed for 1 day in acidogenesis reactor, the hydraulic reaction time (HRT) was 29 days in methane reactor and total HRT was 30 days. The two-stage methane reactor reached steady state had the following results. MPR was 13.8 ± 11.1 mL/L. Methane yield was 9.1 ± 7.3 mL/g VS. Total chemical oxygen demand removal was 84 ± 6%. Volatile solids (VS) removal was 87 ± 5%. As the results of this study, the methane yield of single-stage is better than two-stage which are 29.5 ± 13 mL/g VS and 9.1 ± 7.3 mL/g VS respectively. Nevertheless, the COD removal and VS removal in two-stage are 84 ± 6% and 87 ± 5% performed better than single-stage’s COD removal 81 ± 8% and VS removal 83 ± 9%. Under the efficiency of chicken manure treatment, two-stage anaerobic fermentation is noticeably superior to the single-stage anaerobic fermentation. The experiment results indicate the energy potential and the efficiency of organic matter decreasing. The two-stage anaerobic fermentation contributes to reducing Green House Gas (GHG) emission. Keywords: Chicken manure; Anaerobic fermentation; Two-stage; Methane; Biogas.
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Massara, Hafez. "Anaerobic treatment of hexavalent chromium in industrial effluent using two-phase anaerobic sequencing batch reactor." Thesis, 2006. http://spectrum.library.concordia.ca/9257/1/NR40796.pdf.
Full textAbstract:
Hexavalent chromium pollution is a major environmental concern due to its toxicity and extensive use in industry. Industrial effluents containing Cr(VI) have been traditionally treated by chemical reduction, followed by precipitation, or more recently, by removal using non-viable biosorbents. This study investigates the use of a two-phase anaerobic sequencing batch reactor (ASBR) for the treatment of Cr(VI) contaminated wastewater. Simulated wastewater containing potassium chromate and sucrose was introduced into reactor one which contained phase I optimized biomass. Complete sorption and reduction of Cr(VI) to Cr(III) occurred in reactor one, which had a 1:1 volume of treated wastewater to settled cheese whey biomass granules. The chromium-free effluent from reactor one, rich in volatile fatty acids (VFA) was the feed stock or influent for reactor two, where optimum methane production was maintained. Reactor one was operational for about 40 days with a Cr(VI) loading of 25 mg/L-day. Cr(III) derived from the reduction of Cr(VI) occurred in the effluent of reactor one at levels between 1 to 2.5 mg/L only from about day 28 to the end of the experiment. Selective sequential extraction (SSE) of the spent biomass showed that 45% of the added chromium was in the form of insoluble Cr(III) hydroxides, and the remaining 55% as organo-Cr(III) complexes. VFA levels were eventually reduced in reactor one by about 50%, and soluble COD removal by about 65%. Average methane content in the reactor two biogas was greater than 80%. Based on sorption studies, and using a novel approach whereby sorbed Cr(VI) was interpreted as a "dose" in order to obtain various toxicological indices, models were developed for estimating the amount of Cr(VI)-wastewater that could be treated using plant size unit operations. Leaching tests carried out on spent biomass from reactor one over a five month period demonstrated the non-leacheability of chromium. This study indicated the potential feasibility of using a two-phase ASBR system for the co-treatment of inorganic Cr(VI) contaminated wastewater and high organic loading effluents.
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Phat, Vo Tan, and 武譚柏. "Biohythane production via single-stage anaerobic fermentation in a two-compartment bioreactor." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/pv2j9a.
Full textAbstract:
碩士逢甲大學
綠色能源科技碩士學位學程
107
The uncontrolled discharge of large amounts of food waste (FW) causes severe environmental pollution in many countries. However, FW has a high energy potential of being converted into bioenergy. Within different possible treatment routes, anaerobic digestion of FW into biogas, is a proven and effective solution for FW treatment and valorization. Hydrogen and methane are the potential alternative energy carriers with autonomous extensive and viable importance. The mixture of hydrogen and methane is hythane and it gains attention due to its advantages as a valuable fuel. Furthermore, biohythane is a better transportation fuel than compressed natural gas in terms of high range of flammability, reducing ignition temperature as well as time, low nitrous oxide (NOx) emissions and improving engine performance without specific modification. On the one hand, considering their complementary properties, co-production of a mixture of hydrogen and methane in the form of biohythane in two-stage anaerobic digestion process is gaining more interest than their individual production due to its advantages of hydraulic retention time (HRT), high energy recovery, high chemical oxygen demand (COD) removal, higher hydrogen and methane yields, and reducing carbon dioxide in biogas. On the other hand, such anaerobic biohythane productions using two separated bioreactors require more processes and cost for storing and mixing hydrogen and methane. The present study dealt with the potential biohythane production in a two-compartment (lower, hydrogenesis; upper, methanogenesis) reactor (TCR) via a single-stage anaerobic fermentation at mesophilic temperature. Two main conditions were tested (1) the effect of various HRTs of 10, 7, 5, 3 and 2 d using FW as a substrate (40 g COD/L), (2) the effect of various substrate concentrations of 10, 20, 40 and 80 g COD/L at a constant HRT of 2 days. In investigating the effects of HRTs on biohythane potential experiments, HRT 2 d resulted in peak hydrogen and methane production rates with values of 714 and 254 mL/L-d, respectively and had contents of hydrogen 8.6% and methane 48.0% in the produced gas. At this HRT, Clostridium sensu stricto 2 and Methanosaeta were dominant species in H2 and CH4 compartments, respectively. Moreover, substrate concentrations (SCs) were significantly correlated with biogas production. At SC 10 g COD/L, almost no hydrogen production was observed during steady-state while at an optimal SC of 40 g COD/L, higher hydrogen production was obtained than at 80 g COD/L, approximately fourfold compared to 20 g COD/L. There was insignificance in increasing hydrogen production when SC was changed from 40 to 80 g COD/L; furthermore, the methane production was negatively affected due to high SC. The novelty of this work is creating a two-compartment reactor for single-stage anaerobic biohythane fermentation. However, there are a variety of improvements needs applying in TCR to enhance biohythane productivity as well as organic removal efficiency.
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Hwang, Jong Hyuk. "Two Stage Membrane Biofilm Reactors for Nitrification and Hydrogenotrophic Denitrification." 2010. http://hdl.handle.net/1993/3870.
Full textAbstract:
Membrane biofilm reactors (MBfR) utilize membrane fibers for bubble-less transfer of gas by diffusion and provide a surface for biofilm development. Nitrogen removal was attempted using MBfR in various configurations - nitrification, denitrification and consecutive nitrification and denitrification.
Effects of loading rate and dissolved oxygen on nitrification performance were primarily investigated in a stand-alone nitrifying MBfR. Specific nitrification rate increased linearly with specific loading rate, up to the load of 3.5 g N/m²d. Beyond that load, substrate diffusion limitation inhibited further increase of specific nitrification rate. 100% oxygen utilization was achievable under limited oxygen supply condition.
Effects of mineral precipitation, dissolved oxygen and temperature on hydrogenotrophic denitrification were investigated in a stand-alone denitrifying MBfR. Mineral precipitation, caused by intended pH control, caused the deterioration of denitrification performance by inhibiting the diffusion of hydrogen and nitrate. Operating reactor in various dissolved oxygen conditions showed that the denitrification performance was not affected by dissolved oxygen in MBfR. Optimum temperature of the hydrogenotrophic denitrification system was around 28°C.
Total nitrogen removal in a two-step MBfR system incorporating sequential nitrification and hydrogen-driven autotrophic denitrification was investigated in order to achieve nitrogen removal by autotrophic bacteria alone. Long-term stable operation, which proved difficult in previous studies due to excessive biofilm accumulation in autotrophic denitrification systems, was attempted by biofilm control. Nitrification performance was very stable throughout the experimental periods over 200 days. Performance of autotrophic denitrification was maintained stably throughout the experimental periods, however biofilm control by nitrogen sparging was required for process stability. Biofilm thickness was also stably maintained at an average of 270 µm by the gas sparging biofilm control.
According to the cost analysis of denitrifying MBfR, hydrogenotrophic denitrification can be an economical tertiary treatment option compared to conventional denitrifying filter although its economic feasibility highly depends on the cost of hydrogen gas.
Although this study was conducted in a lab-scale, the findings from this study can be a valuable stepping stone for larger scale application and open the door for system modifications in future.
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Man-ChienChung and 鐘曼倩. "Study of a two-stage anaerobic energy production process treating bagasse bioethanol residues." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/35787891202004583953.
Full textAbstract:
碩士國立成功大學
環境工程學系碩博士班
101
Global warming and energy crisis have already been proved as internal issues in recent years. The governments paid much attention to finding a clean and renewable energy. Therefore, developing biomass energy is main purpose for many counties. Biomass is considered as a carbon neutral source of energy because the carbon dioxide released into atmosphere by using biomass is recovered again by growth of new biomass. Bioethanol is one of biomass energy. Current technologies can only utilize 75-80% of the energy during cellulosic bioethanol fermentation, which implies that 20-25% might be wasted as residues. Thus, this study has focused on the energy recovery from cellulosic bioethanol residues. The characteristics of the bagasse alcohol fermentation residue were studied. The COD was 30000 mg/L, with a large amount of organics. For the electron distribution, carbohydrates comprised 37% of the total COD, and this portion can be fermented to hydrogen. On the other hand, the remaining organic acids (12%) and alcohols (42%), together with the volatile fatty acids produced in hydrogen fermentation, can further be utilized by methanogens to produce methane as energy product. Therefore, a two-stage bioreactor with hydrogen fermentation and methanogenesis was established in this study to treat this bagasse alcohol fermentation residue. There were nine runs in the CSTR anaerobic hydrogen fermentation tank. The maximum specific H2 production rate and yield were investigated to be 37.64 mL H2/g VSS/hr and 29.21 mL H2/g COD when volumetric loading rate (VLR) was 180 kg COD/m3/day. By carrying out batch experiment, shortening HRT could enhance hydrogen yield and the loading of microorganism to substrate .Acetogenesis and S0/X0, or F/M ratio in CSTR, were found to be important factors on the efficiency of biohydrogen production. B/A ratio has been used as an indicator for evaluating the effectiveness of biohydrogen production. The best performance of the methane bioreactor in the view of methane production was obtained under VLR of 3.7kg COD/m3/day, in which 1.12 L CH4/L/day was achieved. Approximately 87.1% of the COD in the bioethanol-fermentation residues was removed, with about 0.3% and 78.9% of it were recovered in the forms of hydrogen and methane. Results indicate that cellulosic bioethanol residues are also suitable for hydrogen and methane fermentation.
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Ribeiro, João Miguel dos Santos. "Two-Phase Acid/Gas Anaerobic Reactor for Industrial Wastewater of Food & Drink SME Industries." Master's thesis, 2016. http://hdl.handle.net/10362/31887.
Full textAbstract:
Food and beverage wastes are rich in organic material such as carbohydrates, proteins, oils, fats, sugars and others. Those high levels of organic material translate in high amounts of chemical oxygen demand (COD) and biochemical oxygen demand (BOD) which cause several pollutions problems, such as water quality degradation and air pollution. Anaerobic digestion (AD) appears as a great solution given its ability to treat and convert organic matter into biogas.
The current objective is to use a two-phase AD to treat wastes from juice (apple pulp) and winery industry (winery waste with grape concentrated (WWGC)) in order to convert as much COD into biogas. For this, several operational conditions were studied.
Firstly, biogas was produced when treating waste apple pulp. The best conditions for the acidogenic phase were: Organic loading rate (OLR) of 35.05±2.30 g COD/(L.day); Hydraulic retention time (HRT) of 1 day; T 30ºC; pH of 5.45. The yield in terms of VFAs conversion from sugar was 0.46 g ΔVFA COD/g sugar COD. For the methanogenic phase, the best conditions studied were: OLR of 7.26±0.38 g COD/(L.day); HRT of 2.5 days; T 37ºC; pH of 7.5. The methane yield achieved was 0.32±0.03 L CH4/g COD.
Secondly, WWGC was treated using the two-phase AD producing biogas. In the acidogenic phase, the optimum conditions were: OLR of 23.20±6.51 g COD/(L.day); HRT of 1 day; T 30ºC; pH of 5.45. The yield of VFAs conversion was 0.50±0.23 g ΔVFA COD/g sugar COD. In the methanogenic phase, the highest methane yield achieved was 0.34±0.03 L CH4/g COD with the following conditions: Organic loading rate of 9.70±0.81 g COD/(L.day); HRT of 2 days; T 30ºC; pH of 7.5.
Optimization of the operational conditions lead to a better performance of the two-phase AD process when treating both wastes tested. A significant COD removal and a high methane yield were achieved for both wastes.
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Huang, Chau-yi, and 黃朝翌. "Hydrogen and methane production from waste syrup using a two-stage anaerobic fermentation process." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/89794857743965308636.
Full textAbstract:
碩士逢甲大學
化學工程學所
100
In this study, the syrup scrap the two-stage fermentation production of hydrogen and methane, non-food source material can improve the competitiveness of bio-fermentation, the effluent of hydrogen reactor conclude rich in volatile acids and alcohols, the two-stage fermentation operation not only degradation COD, but also for methane energy to achieve the purpose of energy recovery; addition, it enables the acidogens bacteria and methanogens operating its optimization of conditions, to have a betterthe production and yield. The batch experiments to explore the impact of environmental factors on methane fermentation, first. In temperature experiments, the sludge of Fu-tian water recycling centers sludge digestion tank sludge (FT) has a better performance, and high temperatures promote bacterial activity, and speed up the digestion the rate, at 55℃ methane production system rate of 35℃, 2.3 times, is approximately 108 mL/h. pH 7.5 in different initial pH batch experimental production system methane test, while the methane yield the better performance to 34.3 mL/g CODre. After methane fermentation, the pH value is roughly located in between 7.5 and 8.0, the initial pH value of the methane fermentation no significant impact, suggesting that the system flora on their own to create a suitable growing environment. At different substrate concentration batch production system methane tests, the ratio between methane production into increased; of produce methane rate and methane yield in tandem with the increase in the substrate concentration and elevated. Further test produced hydrogen out of the flow of liquid remaining in the nutrient adequacy the supply batch production system methane test used, the result is not much different, have enough nutrients contained in the hydrogen production flow solution as methane fermentation The leaven use, no further additional nutrients. The two-phase anaerobic digestion system, the performance of the hydrogen production system at HRT 6 h, total sugar 20 g/L, HPR and HY were 0.717±0.037 mol/L/d and 0.318±0.013 mol H2/mol glucose. Add the columnar activated charcoal effective cell amount is too low to good system, and to improve and degradation rate of the PRB methane fermentation system at HRT 36 h, the feed concentration of 13.2±0.7 g COD/L under the conditions of its MPR up to 83.0±1.5 mmol/L/d, the methane concentration was 79.3 ± 0.5%.
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林嘉祥. "Continuous production of hydrogen and methane from waste syrup by two-stage anaerobic fermentation." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/51163857579657005709.
Full textAbstract:
碩士逢甲大學
化學工程學系
102
In this study, the two-stage fermentation production of hydrogen and methane from waste condensed syrup was explored. A continuous flow stirred tank reactor (CSTR) was used for hydrogen production and operated at 37oC, pH 5.75, and total sugar concentration 20 g/L. In addition, the hydraulic retention time (HRT) was adjusted to 12, 6, or 4 h according to the feeding rate of methane-producing reactor. At HRT 6 h, the CSTR reactor could be operated for 783 days at steady state; and the HPR, HY and HPE was 0.733-0.864 mol/L/d, 1.75-1.85 mol H2/mol glucose and 40-43%, respectively. The reactors of methane production behind H2-producing reactors were carried out various tests at 35 and 55oC, respectivrly. The methophilic methane fermentation used UFR (upflow reactor), AGSB (agitated granular sludge bed), and PBR (packed bed reactor), respectively, to conduct vatious tests. All reactors were operated at pH 7.0, substrate concentration 14 g COD/L, and HRT 36 h. The UFR system had obviously perturbation and biofilm formation in the tank, but methane production efficiency was not good due to biomass washout easily. The AGSB system had better methane production efficiency than UFR system; the MPR, MY, and two-stage SCOD removal efficiency was 88.6-96.5 mmol/L/d, 12.5-15.5 mmol CH4/g CODre, and 85.3-90.5%, respectively. However, methane production rate decreased in the later period because H2S produced or the biomass was washout. Then, the red brick powder was added to the AGSB reactor to promote formation of granular sludge. However, the results showed that it was ineffective because the paticle size of red brick powder was too small resulting in clogging the inlet of reactor. Finally, the PBR system packed red brick granule was used to test. However, the efficiency of methane production was not good; the MPR, MY, and two-stage SCOD removal efficiency was 31.4 mmol/L/d, 10.8 mmol CH4/g CODre, and 64.8%, respectively. The thermophilic methane fermentation used an AGSB reactor to conduct vatious tests; the reactor operated at pH 7.0, substrate concentration 14 g COD/L, and HRT 60 h. In early days, granulation of sludge was obvious and the efficiency of methane production was good; the MPR, MY, and two-stage SCOD removal efficiency was 82.2 mmol/L/d, 15.8 mmol CH4/g CODre, and 96.8%, respectively. However, the performance of system decreased in the later period because of biomass washout. It did not promote the performance of system even though the agitation rate decreased from 100 to 50 rpm. Thus, a PBR reactor packed shell sand filling 50% of bed height was used to carry out tests. However, due to small particle size of shell sand, the inlet was clogged with shell sand resulting in influencing the operation of system. Therefore, the filler was changed cylindrical activated carbon. The results showed that the efficiency of methane production increased because of uncreasing biomass retention. The MPR, MY, and two-stage SCOD removal efficiency was 85.3 mmol/L/d, 18.6 mmol CH4/g CODre, and 93.7%, respectively, at HRT 60 h. When HRT decreased to 36 h, the MPR and MY increased to 105.8 mmol/L/d and19.5 mmol CH4/g CODre, respectively. but removal efficiency decreased to 75.4%. The overall methane production efficiency of these two operations was no significant difference.
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Peng, Tzu-Huan, and 彭子桓. "Development of the low-temperature two-stage fluidized bed reactor for the waste incineration." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/63448029524201550475.
Full textAbstract:
博士國立中興大學
環境工程學系所
103
The aim of this study is to develop a low-temperature two-stage fluidized bed (LTTSFB) reactor system for municipal solid waste incineration. Compared with the traditional waste incineration process, this new system has low construction costs, low energy loss, and less pollutant emission owing to its lower first-stage combustion temperature. During the low-temperature treatment process, it may produce the high unburned substance. Thus, a high temperature second-stage fluidized bed was also employed after the low-temperature first-stage combustor. In this study, artificial waste was used to simulate the municipal solid waste. First, the study focuses on the effect of different first-stage operating conditions on the bottom ash of loss on ignition (LOI), carbon monoxide (CO) emission and heavy-metal emission during this LTTSFB system. After that, the effect of different chloride additives on pollutant emission during the LTTSFB system was also considered. On other hand, in order to understand the mechanism of the second-stage sand bed on controlling the pollutant emissions, different parameters of the second-stage sand bed were studied further. Final, the metal pattern in LTTSFB incinerator bottom ash was also analyzed by chemical sequential extraction to understand its utilization. As the results shown, the first-stage temperature should be maintained above 500 °C due to maintaining the better LOI quality in bottom ash. Although, a large amount of CO was emitted from the low-temperature first-stage combustor, it was efficiently consumed in the second-stage fluidized bed combustor. Compared with the traditional one-stage fluidized bed and LTTSFB system, the heavy-metal emissions can be decreased by between 16% and 82% in the LTTSFB system. The high removal efficiency of heavy-metal was ascribed to the silica sand adsorption in different stages, low operating temperature of first-stage, and the filtration of the second-stage. In addition, after the Cl additives addition, the Cl would reduce the metal capture in the first-stage sand bed. Fortunately, those emitted metals could be effectively captured by the filtration of second-stage. Regarding on the other kind of gas pollutants, the results showed that the NOx and HCl emission from LTTSFB system also could be controlled efficiently. Moreover, after the high temperature second-stage fluidized bed treatment, 70 – 76 % organic pollutants (PAHs and BTEXs) could be decreased. And the results also indicated that the heavy-metal and organic pollutant were a positive correlation with particulate matter emission during the LTTSFB system. Regarding on the different operating conditions of the second-stage fluidized bed, the particle size of the sand bed was the major factor to affect the pollutant emissions. The main reason may be explained by the minimum fluidization velocity (Umf ) changed. As the Umf changed, it affected the superficial velocity of the flue gas in the second-stage sand bed. During the LTTSFB system, the heavy-metal emission could be controlled very well. However, from the chemical sequential extraction result, it showed that high concentration of mobility heavy-metals was found in the residual ashes. Thus, it should be noticed that the residual ashes produced by the LTTFB system must be taken into consideration given their high mobility.
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CHIN, LO, and 羅敬. "Improvement of the Biogas Production by Anaerobic Two-stage Commercialized Process from Pig Farm Wastewater." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/p36g25.
Full textAbstract:
碩士逢甲大學
綠色能源科技碩士學位學程
107
Taiwan's animal husbandry wastewater is one of the main causes of river pollution. In the traditional livestock wastewater treatment method, there are still some problems, such as low biogas production, post-treatment of sludge, and low efficiency of wastewater treatment. Bio-anaerobic fermentation produces biogas technology, which converts waste water that would otherwise be discharged into energy, recycles and reuses wastewater and sludge, and produces biogas while treating sewage. Therefore, this technology is applied to a new type of livestock wastewater treatment plant. Then, the gas produced by the production of biogas is purified to carry out biogas power generation to achieve the purpose of energyizing waste water. This study is to produce biogas at the commercial scale of anaerobic two-stage digestion in Xinhexing Ranch in central Taiwan. It will be monitored for a long time from September 2018 to July 313 in 313 days. The source of the substrate is from the farm. The average chemical oxygen demand of pig manure and urine wastewater was 70.4 g COD/L, average suspended solids (TS) 62.5 g/L, average suspended solids (SS) 59.4 g/L, average volatile solids (VS) 44.9 g/ L and the average total sugar 1.7 g total sugar/L. During the monitoring period, the average number of pigs in the head is 1,500, and the average amount of wastewater per day is 60 m3/d. The wastewater treatment steps include collection tank, mixing tank, pre-anaerobic tank, main anaerobic tank, primary sedimentation tank, and exposure. The gas pool and the final settling tank are discharged to the discharge tank after these procedures. The volume of the front anaerobic tank is 60 m3, the hydraulic retention time (HRT) is 24 hours, and the average monitoring temperature and pH value are 30 ° C and 7.0 respectively. . The main anaerobic tank has a volume of 600 m3, a hydraulic retention time of 240 hours, and a temperature and pH of 30 ° C and 7.5, respectively. During the 313 days of operation, the average removal rate of COD in the anaerobic two-stage inflow and outflow was 96.7%, the average TS removal rate was 98%, the average SS removal rate was 99.7%, and the average VS removal rate was 99.0%. The biomethane content is 81.3% and the average biogas production rate is 185 m3/d.
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Sanhueza-Torres, Elizabeth Patricia. "Study of the effect of low levels of oxygen during the anaerobic stage in biological phosphorus removal, using a lab-scale sequencing batch reactor." 2004. http://catalog.hathitrust.org/api/volumes/oclc/54495283.html.
Full textAbstract:
Thesis (M.S.)--University of Wisconsin--Madison, 2004.Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 27-29).
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Mateus, Sara Alexandra Anacleto. "From fruit pulp wastes to biomethane: assessment of substrate shifts on the performance of a two-stage anaerobic system and biogas upgrading studies." Master's thesis, 2017. http://hdl.handle.net/10362/25627.
Full textAbstract:
Wastes with high organic content, such as food waste, are produced worldwide and can cause serious pollution problems when poorly managed. Thus, there is the need for the implementation of environmental friendly treatment systems for organic wastes. Anaerobic digestion has the potential to contribute for the sustainable treatment of these wastes while producing biogas which provides a renewable energy source, methane (CH4).
In this study, a two-stage anaerobic system was operated treating three different fruit pulp wastes (peach, raspberry and white guava) in a sequential operation. The effect of substrate shifts and different operational conditions, such as hydraulic retention time (HRT), organic loading rate (OLR) and pH on the system’s performance was assessed. The shift of substrates caused no long-term instability issues. The differences observed in the acidogenic performance in terms of gas production between substrates were considerable. Conversely, only slight differences were observed in fermentation products (FP) concentration and profiles. No evident association was found between pH and HRT/OLR changes on FP concentration and profiles in the range studied. Overall, the sugar removal efficiencies obtained were between 93.8 – 97.8% and the acidification degree varied between 53.7% – 76.4%. In regard to the methanogenic reactor, biogas production (3.6 – 12.8 L d-1) increased as OLR increased up to 7.4 g COD L-1, while CH4 yield (0.30 – 0.37 L CH4 g-1 COD) and content (75.9– 80.6%) remained approximately constant. Maximal chemical oxygen demand (COD) removal
efficiency (around 93%) was achieved at HRTs of 8.6 and 5 days (OLR of 1.9 – 3.7 g COD L-1 d-1).
Currently, there is the need to develop effective and economical viable solutions for biogas upgrading.
Thus, gas permeation studies using mixed-matrix membranes (MMMs) with two different metal organic frameworks (MOFs) - MIL-53 and MOF-5 - were carried out in other to assess the potential for CH4 and carbon dioxide (CO2) separation. Matrimid®5218 with 10% (w/w) MIL-53 membrane showed the best performance among the membranes tested.
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Δαρειώτη, Μαργαρίτα. "Energy valorization of agro-industrial wastes and sweet sorghum for the production of gaseous biofuels through anaerobic digestion." Thesis, 2015. http://hdl.handle.net/10889/8753.
Full textAbstract:
It is clear that renewable resources have received great interest from the international community during the last decades and play a crucial role in the current CO2-mitigation policy. In this regard, energy from biomass and waste is seen as one of the most dominant future renewable energy sources. Thus, organic waste i.e. animal wastes, wastewaters, energy crops, agricultural and agro-industrial residues are of specific importance since these sources do not compete with food crops in agricultural land usage. The various technologies that are available for power generation from biomass and waste can be subdivided into thermochemical, biochemical and physicochemical conversion processes. Anaerobic digestion (AD), classified within the biochemical conversion processes, is a robust process and is widely applied. Various types of biomass and waste, can be anaerobically co-digested to generate a homogeneous mixture increasing both process and equipment performance.
This study focused on the valorization of agro-industrial wastes (such as olive mill wastewater (OMW), cheese whey (CW) and liquid cow manure (LCM)) and sweet sorghum stalks. Olive mills, cheese factories and cow farms are agro-industries that represent a considerable share of the worldwide economy with particular interest focused in the Mediterranean region. These industries generate millions of tons of wastewaters and large amounts of by-products, which are in many cases totally unexploited and thus dangerous for the environment. On the other hand, sweet sorghum as a lignocellulosic material represents an interesting substrate for biofuels production due to its structure and composition.
Anaerobic co-digestion experiments using different mixtures of agro-industrial wastes were performed in a two-stage system consisting of two continuously stirred tank reactors (CSTRs) under mesophilic conditions (37°C). Subsequently, more mixtures were studied, where sweet sorghum was added, in order to simulate the operation of a centralized AD plant fed with regional agro-wastes which lacks OMW or/and CW due to seasonal unavailability. Two operational parameters were examined in a two-stage system, including pH and HRT. Batch experiments were performed in order to investigate the impact of controlled pH on the production of bio-hydrogen and volatile fatty acids, whereas continuous experiments (CSTRs) were conducted for the evaluation of HRT effect on hydrogen and methane production.
Moreover, further exploitation of digestate from an anaerobic methanogenic reactor was studied using a combined ultrafiltration/nanofiltration system and further COD reduction was obtained. On the other hand, vermicomposting was conducted in order to evaluate the sludge transformation to compost and as a result, good results in terms of increased N-P-K concentration values were obtained. Furthermore, simulation of mesophilic anaerobic (co)-digestion of different substrates was applied, using the ADM1 modified model, where the results indicated that the modified ADM1 was able to predict reasonably well the steady-state experimental data.Είναι φανερό ότι οι ανανεώσιμες πηγές ενέργειας έχουν προσελκύσει το ενδιαφέρον της διεθνούς κοινότητας τις τελευταίες δεκαετίες καθώς διαδραματίζουν καθοριστικό ρόλο στην μείωση του CO2. Η ενέργεια από βιομάζα και απόβλητα θεωρείται ως μία από τις πλέον κυρίαρχες ανανεώσιμες πηγές ενέργειας του μέλλοντος. Έτσι, τα οργανικά απόβλητα όπως κτηνοτροφικά, ενεργειακές καλλιέργειες, γεωργικά και βιομηχανικά υπολείμματα κ.ά έχουν ιδιαίτερη σημασία, δεδομένου ότι οι πηγές αυτές δεν ανταγωνίζονται με τις καλλιέργειες τροφίμων της γεωργικής γης και ωστόσο μπορούν να χρησιμοποιηθούν για την παραγωγή ηλεκτρικής ενέργειας, θερμότητας και βιοκαυσίμων. Το αυξημένο ενδιαφέρον για τις διεργασίες που αφορούν στη μετατροπή της βιομάζας σε ανανεώσιμες πηγές ενέργειας, όπως είναι η αναερόβια χώνευση, τόνωσε την έρευνα σε αυτόν τον τομέα με αποτέλεσμα την υλοποίηση ενός σημαντικού αριθμού ερευνητικών έργων για να αξιολογηθούν οι ιδανικές συνθήκες χώνευσης διαφόρων υποστρωμάτων, όπως είναι τα αγροτο-βιομηχανικά απόβλητα και οι ενεργειακές καλλιέργειες. Στη παρούσα διατριβή πραγματοποιήθηκαν πειράματα αναερόβιας συγχώνευσης χρησιμοποιώντας αγροτο-βιομηχανικά απόβλητα ή/και γλυκό σόργο. Τα αγροτο-βιομηχανικά απόβλητα, όπως είναι τα απόβλητα ελαιοτριβείου, τυροκομείου αλλά και βουστασίου, χαρακτηρίζονται από υψηλό οργανικό φορτίο και συνεπώς θεωρούνται ακατάλληλα για απευθείας διάθεση σε περιβαλλοντικούς αποδέκτες. Συγχώνευση αυτών οδήγησε σε υψηλές αποδόσεις μεθανίου κάτι το οποίο οφείλεται σε συνεργιστικές επιδράσεις όπως η συμβολή επιπλέον αλκαλικότητας, ιχνοστοιχείων, θρεπτικών κτλ. Περαιτέρω μίγματα μελετήθηκαν χρησιμοποιώντας το γλυκό σόργο με σκοπό την προσομοίωση λειτουργίας μιας κεντρικής μονάδας αναερόβιας χώνευσης, η οποία τροφοδοτείται με τοπικά απόβλητα τα οποία θα αντικατασταθούν σε περίοδο μη εποχικής διαθεσιμότητας από το γλυκό σόργο. Τα μίγματα αυτά μελετήθηκαν σε διβάθμιο σύστημα διερευνώντας την επίδραση των δύο σημαντικότερων λειτουργικών παραμέτρων (του pH και του υδραυλικού χρόνου παραμονής, HRT) στην απόδοση του συστήματος. Πιο συγκεκριμένα, πραγματοποιήθηκαν πειράματα διαλείποντος έργου προκειμένου να διερευνηθεί η επίδραση του pH στην παραγωγή υδρογόνου και μεταβολικών προϊόντων, ενώ πειράματα συνεχούς λειτουργίας διεξήχθηκαν για τη μελέτη της επίδρασης του HRT στην παραγωγή υδρογόνου και μεθανίου σε διβάθμιο σύστημα. Περαιτέρω αξιοποίηση του χωνευμένου υπολείμματος μελετήθηκε με χρήση συνδυασμένου συστήματος υπερδιήθησης/νανοδιήθησης επιτυγχάνοντας επιπρόσθετη μείωση του οργανικού φορτίου στο διήθημα. Η μετατροπή της αναερόβια χωνευμένης ιλύος σε λίπασμα αξιολογήθηκε μέσω κομποστοποίησης με γεωσκώληκες (vermi-composting) επιτυγχάνοντας ικανοποιητικά αποτελέσματα στην αύξηση των συγκεντρώσεων N-P-K. Επιπλέον, αναπτύχθηκε τροποποιημένο μοντέλο της αναερόβιας χώνευσης (ADM1) με στόχο την προσομοίωση της αναερόβιας συγχώνευσης διαφορετικών υποστρωμάτων. Τα αποτελέσματα που προέκυψαν έδειξαν ότι το μοντέλο ήταν σε θέση να προβλέψει σε ικανοποιητικό βαθμό την πορεία των πειραματικών δεδομένων.