Sewage sludge is widely used as an important source for biogas production through digestion. Developing the high performance processes has a significant goal in order to promote energy efficiency and reduce the cost sewage sludge treatment. The problem of sewage sludge disposal is becoming top one which almost cost 50 % of running fee for a municipal wastewater treatment plant. This paper basically introduces three methods to improve the conventional digestion. However, they enhance the conventional digestion from different aspects. For examples, Two-phase anaerobic digestion enables to exhibit the merit of thermophilic anaerobic digestion and avoid the weak points of conventional digestion regarding odor problem. In two-phase anaerobic digestion, the acid and methane producing stages are separated. Extended solids retention time is an approach to separate the hydraulic retention time and solids retention time in an anaerobic digester by using recycle thickening. This method could benefit further de-composing the organics and increase methane formation. Dewaterability is the final step of anaerobic digestion process. Enhancing this part of process is an efficient way to increase the solid content of sludge that would reduce the transportation costs. In a nutshell, no matter on saving cost or energy perspectives, these three methods all promote biogas production efficiency up to a better performance, but various requirement of energy and cost are demanded. The paper displays and compares the advantages and disadvantages among three methods. There is no certain answer to which method is the best one; however, they can be chose to enhance digestion in different condition.

The effect of solids retention time (SRT) or sludge age on activated sludge properties and effluent quality was investigated using laboratory scale reactors. It was found that an increase in SRT resulted in an increase in effluent solution polysaccharide, with the < 3,000 daltons (3K) size fraction contributing up to 68 percent of solution polysaccharides. The feed consisted of low molecular weight, readily degradable protein, suggesting that the observed increases in protein and polysaccharide were due to increased release of exocellular microbial product (EMP). The increase in solution protein and polysaccharide resulted in an increase in effluent chemical oxygen demand (COD). The increase in effluent COD was not accompanied by a similar increase in effluent biological oxygen demand (BOD), indicating that the EMPs released were resistant to biodegradation. At the highest SRT, the resistance to shear decreased and the capillary suction time (CST) increased. Following an initial increase, the sludge volume index (SVI) decreased at higher SRT. / Master of Science

京都大学 / 新制・論文博士 / 博士(工学) / 乙第13617号 / 論工博第4214号 / 京都大学大学院人間・環境学研究科相関環境学専攻 / (主査)教授 田中 賢治, 教授 中北 英一, 教授 佐山 敬洋 / 学位規則第4条第2項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

Die Verdaulichkeit langsam abbaubarer Pflanzenbestandteile (Cellulose) steigt mit zunehmender Partikelverweilzeit im Vormagen von Wiederkäuern. Die Ingestaverweilzeit im Magen-Darm-Kanal ist abhängig von der Größe der Fermentationskammern, der Nahrungsaufnahme, vom Speichelfluß und von der selektiven Retention von Futterpartikeln. Die mittlere Retentionszeit (MRT) von Flüssigkeit und Partikeln müßte sich zwischen den Tierarten unterscheiden und saisonbedingt in Abhängigkeit von der Qualitüt und des Angebotes der Nahrung verändern. Mit der Messung der Ingestapassage an Rehen als Konzentratselektierer im Vergleich zu Mufflons als Grasfresser werden Faktoren der Anpassung an das jahreszeitlich wechselnde Nahrungsangebot dieser verschiedenen Wildtierarten untersucht. Voraussetzung für die Durchführung der Versuche war die Handaufzucht von sechs Rehkitzen und fünf Mufflonlämmern. Den Tieren wurde zum dorsalen Pansensack eine Vormagenkanüle implantiert. Die Haltung der Tiere erfolgte in Gehegen mit natürlicher Vegetation. Den Rehen und Mufflons wurden über die Vormagenfistel ein Marker für Flüssigkeit (Co-EDTA) und ein Marker für Partikel (Chrom-markiertes Heu) verabreicht. Anschließend wurde 5 Tage regelmäßig alle 3 bis 4 h Kot gesammelt. Die Co-/Cr-Konzentrationen der mit Schwefelsäure aufbereiteten Proben wurden atomabsorptionsspektrometrisch gemessen. Die Berechnung der Retentionszeiten der Flüssigkeit und Partikel im Gastro-Intestinal-Trakt (GIT) und im Ruminoretikulum (RR) erfolgte nach Thielemans et al. (1978), nach Grovum und Williams (1973) und Lechner-Doll (1990). Derartige Untersuchungen wurden erstmals unter annähernd natürlichen Bedingungen vergleichend an Rehen und Mufflons durchgeführt. Die Gesamtverweildauer von Flüssigkeit und Partikeln im Gastro-Intestinal-Trakt war beim Reh (MRTFlüss.GIT = 18,1 ± 2,4 h, MRTPart.GIT = 23,6 ± 3,8 h) im gesamten Jahresverlauf kürzer als beim Mufflon (MRTFlüss.GIT = 22,5 ± 3,9 h, MRTPart.GIT = 36,0 ± 4,2 h). Die Partikelverweilzeit im Ruminoretikulum beim Reh betrug MRTPart.RR =13,9 ± 3,1 h und beim Mufflon MRTPart.RR = 24,8 ± 3,0 h. Flüssigkeit verweilte im Ruminoretikulum beim Reh MRTFlüss. RR = 8,0 ± 1,0 h und beim Mufflon MRTFlüss.RR = 11,5 ± 2,0 h. Bei beiden Tierarten waren die Retentionszeiten der Ingesta im Gastro-Intestinal-Trakt erheblichen jahreszeitlichen Schwankungen unterworfen. Sie waren im Herbst bei erhöhter Nahrungsaufnahme verkürzt und im Winter durch eine Reduzierung des Stoffwechsels und der Aufnahme von Pflanzen mit geringerer Verdaulichkeit verlängert. Rehe haben im Gegensatz zu Mufflons einen relativ kleinen Vormagen, weite Verzögerungsstrukturen und einen hohen Speichelfluß, was die kurze Ingestaverweildauer verursachen kann. Aufgrund der kurzen Verweilzeit der Partikel im Ruminoretikulum haben Rehe schlechtere Voraussetzungen für die Verwertung von cellulosehaltigen Pflanzen. Beim Mufflon hingegen schaffen lange Verweilzeiten von Nahrungspartikeln im Ruminoretikulum immer günstige Bedingungen für die Einbeziehung der Cellulose in die energetische Nutzung. Die sich saisonal verändernden Retentionszeiten der Ingesta im Gastro-Intestinal-Trakt machen die Anpassungsfähigkeit beider Tierarten an das jahreszeitlich wechselnde Nahrungsangebot deutlich. / The digestibility of slowly fermentable/digestible plant material (cellulose) increases with increasing particle retention time in the forestomach of ruminants. The retention time in the gastro-intestinal-tract depends on the size of the fermentation chambers, the food intake, the saliva flow and the selective retention of food particles. The mean retention time (MRT) of fluid and particles should differ between ruminant species and, according to differences in food quality and availability, between seasons. By measuring the ingesta passage rate of roe deer, a concentrate selector, in comparison with mouflon, a grass and roughage eater, adaptation factors of these different species to the seasonally changing forage supply were investigated. A prerequisite for the trials was the hand-rearing of six roe deer fawns and five mouflon lambs. Rumen fistulas were implanted in all adult animals leading to the dorsal ruminal chamber. The animals were kept in adequate enclosures with natural vegetation. A fluid (Co-EDTA) and a particle (Cr-mordanted fibre) marker were applied to roe deer and mouflons via the rumen fistula. After marker application, faecal samples were collected every 3 to 4 hours for 5 days. Faecal samples were prepared with sulphuric acid and the Co- and Cr-concentrations were measured by atomic absorption spectrophotometry. The retention time of fluid and particle phase in the gastro-intestinal-tract and in the ruminoreticulum were calculated according to Thielemans et al. (1978), Grovum und Williams (1973) und Lechner-Doll (1990). Such investigations were carried out for the first time under natural conditions comparing roe deer and mouflons. The total retention time of fluid and particles in the gastro-intestinal-tract was for roe deer (MRTfluid GIT = 18,1 ± 2,4 h, MRTpart.GIT = 23,6 ± 3,8 h) shorter than for mouflon (MRTfluid GIT = 22,5 ± 3,9 h, MRTpart.GIT = 36,0 ± 4,2 h ) during the whole year. The retention time of particles in the ruminoreticulum was for roe deer MRTpart.RR = 13,9 ± 3,1 h and for mouflon MRTpart.RR = 24,8 ± 3,0 h. Fluid remained in the ruminoreticulum of roe deer for MRTfluid RR = 8,0 ± 1,0 h and of mouflon for MRTfluid RR = 11,5 ± 2,0 h. For both species, the ingesta retention time in the gastro-intestinal-tract showed significant seasonal fluctuations. They were shorter during autumn, when the animals showed an increased food intake, and longer in winter due to a reduction in both metabolic rate and ingestion of forage of low digestibility. Roe deer, in contrast to mouflon, have a ruminoreticulum characterized by relatively small size and large openings. This anatomy of the ruminoreticulum and the high saliva flow may be the reasons for the short ingesta retention time in the gastro-intestinal-tract of roe deer. Due to the short retention time of particles in the ruminoreticulum roe deer are more limited in their capacity to digest cellulose-containing plants. However longer retention time of food particles in the ruminoreticulum of mouflon provides favourable conditions for cellulose fermentation in all seasons. The seasonally variable ingesta retention time in the gastro-intestinal-tract are an expression of the adaptability of both species to the seasonally fluctuating food supply.

Made available in DSpace on 2017-07-10T19:24:53Z (GMT). No. of bitstreams: 1 Elisangela_texto_completo.pdf: 1937716 bytes, checksum: 8866fb537e08ee2dff81046a562d5d7e (MD5) Previous issue date: 2011-07-07 / The liquid effluent of the starch factories causes serious damage to the environment if discharged without being previously treated, due to the high organic loads and to the presence of cyanide and hydrocyanic acid, which interfere with the respiratory chain of living beings. One alternative treatment for this residue is the implementation of anaerobic reactors, which may enable increase in commercial value through the production of biogas. To provide a high retention of biomass in the system and increase the contact area of the microorganisms with the effluent, inert support means are used, which allow the application of higher loads and reduce the hydraulic detention time. Thus, this study aims to evaluate the performance of anaerobic treatment of starch wastewater, using two reactors with different support means, bamboo and PVC rings. The experiment was conducted in the Laboratory of Environmental Sanitation of the Western Paraná State University Campus Cascavel, using wastewater from the starch in the city of Toledo (PR). Two reactors used PVC with a diameter of 15 cm and 90 cm of length, resulting in a 1:6 ratio. As a conduit, 52 bamboo support rings were used, with an average of 10 cm in length, in one reactor and 325 rings of conduit with 4 cm of average length, resulting in a working volume of 6.00 and 7.98 L, respectively. All thirteen applied loads were gradually increased from 1.675 to 15.158 gL-1.d-1, until reaching the maximum load bearable by the reactors. When the system was stabilized, for each condition of applied load, the collecting of data was carried out for a period of fifteen days, through daily sampling at the entrance and at the exit of the reactors. The samples were analyzed for parameters: COD, total solids, pH, alkalinity, volatile acidity and biogas production. To determine the parameters COD and total, fixed and volatile soils, the methods described in the 2540B and 5220D Standard Methods for the Examination of Water and Wastewater (1998) were used; volatile acids and alkalinity was assessed according to the methodology proposed by Silva (1997). Five sampling points were installed along the length of the reactors to evaluate the process of digestion in the reactor. At these points, samples were collected in duplicate at the end of the period of data collection for each condition of applied load, as well as being analyzed according to parameters such as COD, acetic acid, propionic, and butyric acid, which were determined by high performance liquid chromatography, according to the methodology proposed by Leong & Shui (2002). Some instability in the system was observed in load 12 (12.394 gL-1.d-1), with values of AV / AT above 0.5 and a reduction in pH, but the system started showing signs of stability in the next load. The COD removal did not differ between the two reactors, reaching values of 99.72%. The reactor filled with bamboo had a higher biogas production, with a total production of up to 1.57 LL-1.d-1 and the reactor filled with PVC presented higher removal of total solids: 87.40%. Through the identification of volatile fatty acids from the samples collected along the the reactor, only acetic and propionic acid were found. / O efluente líquido das fecularias causa sérios danos ao meio ambiente quando lançado sem tratamento, devido às elevadas cargas orgânicas e à presença de cianeto e ácido cianídrico, que interferem na cadeia respiratória dos seres vivos. Uma das alternativas de tratamento para esse resíduo é a implantação de reatores anaeróbios, que podem permitir a agregação de valor através da produção de biogás. Para proporcionar uma elevação da retenção da biomassa no sistema e aumentar a área de contato dos microorganismos com o efluente, são utilizados meios suportes inertes, que permitem a aplicação de cargas mais elevadas e a redução do tempo de detenção hidráulico. Desta forma, este estudo teve por objetivo avaliar o desempenho do tratamento anaeróbio de efluente líquido de fecularia, utilizando dois reatores com meios suportes diferentes, de anéis de bambu e de PVC. O experimento foi realizado no laboratório de Saneamento Ambiental da Universidade Estadual do Oeste do Paraná Campus Cascavel, utilizando água residuária proveniente de fecularia localizada no município de Toledo (PR). Foram utilizados dois reatores de PVC com diâmetro de 15 cm e comprimento de 90 cm, resultando em uma relação entre largura e comprimento de 1:6. Como meios suportes foram utilizados 52 anéis de bambu, com média de 10 cm de comprimento, em um dos reatores e 325 anéis de PVC com 4 cm de comprimento médio, resultando em volume útil de 6,00 e 7,98 L, respectivamente. As 13 cargas orgânicas volumétricas aplicadas foram aumentadas gradativamente, de 1,675 a 15,158 g.L-1.d-1, até se atingir a carga máxima suportável pelos reatores. Observada a estabilização do sistema, para cada condição de carga aplicada foi iniciada a coleta de dados por um período de 15 dias, através de amostragens diárias na entrada e saída dos reatores. As amostras foram analisadas quantos aos parâmetros: DQO, sólidos totais, fixos e voláteis, pH, alcalinidade total, acidez volátil e produção de biogás. Para a determinação dos parâmetros DQO e sólidos totais, fixos e voláteis foram utilizados os métodos 2540B e 5220D descritos no Standard Methods for the Examination of Water and Wastewater (1998), ácidos voláteis e alcalinidade foram determinados de acordo com metodologia proposta por Silva (1997). Foram instalados cinco pontos de amostragem ao longo do comprimento dos reatores para avaliar o processo de digestão no perfil do reator. Nestes pontos foram coletadas amostras em duplicata, no final do período de coleta de dados de cada condição de carga aplicada, sendo os mesmos analisados quanto aos parâmetros DQO, ácido acético, propiônico e butírico, que foram determinados através da cromatografia líquida de alto desempenho, conforme metodologia proposta por Shui e Leong (2002). Foi observada uma instabilidade no sistema na carga 12 (12,394 g.L- 1.d-1), com valores de AV/AT acima de 0,5 e redução do pH; porém, o sistema voltou a mostrar sinais de estabilidade na carga seguinte. A remoção de DQO não apresentou diferença entre os dois reatores, chegando a valores de 99,72%. O reator preenchido com bambu apresentou maior produção de biogás, com produção de até 1,57 L.L-1.d-1 e no reator preenchido com PVC foi observada maior remoção de sólidos totais: 87,40%. Na identificação de ácidos graxos voláteis das amostras coletadas ao longo do perfil do reator, somente foram identificados o ácido acético e propiônico.

Made available in DSpace on 2017-05-12T14:48:15Z (GMT). No. of bitstreams: 1 Elisangela_texto_completo.pdf: 1937716 bytes, checksum: 8866fb537e08ee2dff81046a562d5d7e (MD5) Previous issue date: 2011-07-07 / The liquid effluent of the starch factories causes serious damage to the environment if discharged without being previously treated, due to the high organic loads and to the presence of cyanide and hydrocyanic acid, which interfere with the respiratory chain of living beings. One alternative treatment for this residue is the implementation of anaerobic reactors, which may enable increase in commercial value through the production of biogas. To provide a high retention of biomass in the system and increase the contact area of the microorganisms with the effluent, inert support means are used, which allow the application of higher loads and reduce the hydraulic detention time. Thus, this study aims to evaluate the performance of anaerobic treatment of starch wastewater, using two reactors with different support means, bamboo and PVC rings. The experiment was conducted in the Laboratory of Environmental Sanitation of the Western Paraná State University Campus Cascavel, using wastewater from the starch in the city of Toledo (PR). Two reactors used PVC with a diameter of 15 cm and 90 cm of length, resulting in a 1:6 ratio. As a conduit, 52 bamboo support rings were used, with an average of 10 cm in length, in one reactor and 325 rings of conduit with 4 cm of average length, resulting in a working volume of 6.00 and 7.98 L, respectively. All thirteen applied loads were gradually increased from 1.675 to 15.158 gL-1.d-1, until reaching the maximum load bearable by the reactors. When the system was stabilized, for each condition of applied load, the collecting of data was carried out for a period of fifteen days, through daily sampling at the entrance and at the exit of the reactors. The samples were analyzed for parameters: COD, total solids, pH, alkalinity, volatile acidity and biogas production. To determine the parameters COD and total, fixed and volatile soils, the methods described in the 2540B and 5220D Standard Methods for the Examination of Water and Wastewater (1998) were used; volatile acids and alkalinity was assessed according to the methodology proposed by Silva (1997). Five sampling points were installed along the length of the reactors to evaluate the process of digestion in the reactor. At these points, samples were collected in duplicate at the end of the period of data collection for each condition of applied load, as well as being analyzed according to parameters such as COD, acetic acid, propionic, and butyric acid, which were determined by high performance liquid chromatography, according to the methodology proposed by Leong & Shui (2002). Some instability in the system was observed in load 12 (12.394 gL-1.d-1), with values of AV / AT above 0.5 and a reduction in pH, but the system started showing signs of stability in the next load. The COD removal did not differ between the two reactors, reaching values of 99.72%. The reactor filled with bamboo had a higher biogas production, with a total production of up to 1.57 LL-1.d-1 and the reactor filled with PVC presented higher removal of total solids: 87.40%. Through the identification of volatile fatty acids from the samples collected along the the reactor, only acetic and propionic acid were found. / O efluente líquido das fecularias causa sérios danos ao meio ambiente quando lançado sem tratamento, devido às elevadas cargas orgânicas e à presença de cianeto e ácido cianídrico, que interferem na cadeia respiratória dos seres vivos. Uma das alternativas de tratamento para esse resíduo é a implantação de reatores anaeróbios, que podem permitir a agregação de valor através da produção de biogás. Para proporcionar uma elevação da retenção da biomassa no sistema e aumentar a área de contato dos microorganismos com o efluente, são utilizados meios suportes inertes, que permitem a aplicação de cargas mais elevadas e a redução do tempo de detenção hidráulico. Desta forma, este estudo teve por objetivo avaliar o desempenho do tratamento anaeróbio de efluente líquido de fecularia, utilizando dois reatores com meios suportes diferentes, de anéis de bambu e de PVC. O experimento foi realizado no laboratório de Saneamento Ambiental da Universidade Estadual do Oeste do Paraná Campus Cascavel, utilizando água residuária proveniente de fecularia localizada no município de Toledo (PR). Foram utilizados dois reatores de PVC com diâmetro de 15 cm e comprimento de 90 cm, resultando em uma relação entre largura e comprimento de 1:6. Como meios suportes foram utilizados 52 anéis de bambu, com média de 10 cm de comprimento, em um dos reatores e 325 anéis de PVC com 4 cm de comprimento médio, resultando em volume útil de 6,00 e 7,98 L, respectivamente. As 13 cargas orgânicas volumétricas aplicadas foram aumentadas gradativamente, de 1,675 a 15,158 g.L-1.d-1, até se atingir a carga máxima suportável pelos reatores. Observada a estabilização do sistema, para cada condição de carga aplicada foi iniciada a coleta de dados por um período de 15 dias, através de amostragens diárias na entrada e saída dos reatores. As amostras foram analisadas quantos aos parâmetros: DQO, sólidos totais, fixos e voláteis, pH, alcalinidade total, acidez volátil e produção de biogás. Para a determinação dos parâmetros DQO e sólidos totais, fixos e voláteis foram utilizados os métodos 2540B e 5220D descritos no Standard Methods for the Examination of Water and Wastewater (1998), ácidos voláteis e alcalinidade foram determinados de acordo com metodologia proposta por Silva (1997). Foram instalados cinco pontos de amostragem ao longo do comprimento dos reatores para avaliar o processo de digestão no perfil do reator. Nestes pontos foram coletadas amostras em duplicata, no final do período de coleta de dados de cada condição de carga aplicada, sendo os mesmos analisados quanto aos parâmetros DQO, ácido acético, propiônico e butírico, que foram determinados através da cromatografia líquida de alto desempenho, conforme metodologia proposta por Shui e Leong (2002). Foi observada uma instabilidade no sistema na carga 12 (12,394 g.L- 1.d-1), com valores de AV/AT acima de 0,5 e redução do pH; porém, o sistema voltou a mostrar sinais de estabilidade na carga seguinte. A remoção de DQO não apresentou diferença entre os dois reatores, chegando a valores de 99,72%. O reator preenchido com bambu apresentou maior produção de biogás, com produção de até 1,57 L.L-1.d-1 e no reator preenchido com PVC foi observada maior remoção de sólidos totais: 87,40%. Na identificação de ácidos graxos voláteis das amostras coletadas ao longo do perfil do reator, somente foram identificados o ácido acético e propiônico.

Submitted by Fabio Sobreira Campos da Costa (fabio.sobreira@ufpe.br) on 2016-07-01T15:18:35Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertação de Mestrado Versão Final Completa - Gabriela Valones Rodrigues de Araújo.pdf: 2764512 bytes, checksum: 6abd4e4eb59a8eaec35b37f1ac434ba8 (MD5) / Made available in DSpace on 2016-07-01T15:18:35Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertação de Mestrado Versão Final Completa - Gabriela Valones Rodrigues de Araújo.pdf: 2764512 bytes, checksum: 6abd4e4eb59a8eaec35b37f1ac434ba8 (MD5) Previous issue date: 2015-08-28 / CNPq / A remoção de carbono e nitrogênio foi avaliada através de um sistema inovador de reatores anaeróbio, aeróbio e anóxico em série de fluxo contínuo. Foram testadas diferentes condições operacionais quanto ao Tempo de Detenção Hidráulica (TDH) por reator (anaeróbio, aeróbio e anóxico) na Fase 1, Fase 2, Fase 3 e Fase 4 que foi de 7h, 10h, 10h e 5h, respectivamente; e Oxigênio Dissolvido (OD) nas concentrações de 0,5-1,2 mg O2.L-1, 0,5-1,5 mg O2.L-1, 1,1-2,1 mg O2.L-1 e 1,1-2,5 mg O2.L-1 no reator aeróbio, nas respectivas fases. O reator anaeróbio promoveu uma excelente remoção de matéria orgânica (85%), bem como, atuou como pré-tratamento na redução da competição entre os micro-organismos heterotróficos e nitrificantes autotróficos no reator aeróbio. A maior eficiência da nitrificação foi obtida quando a concentração de OD foi mantida entre 1,1 e 2,5 mg L-1. No entanto, foi observada uma diminuição na eficiência da desnitrificação, que pode estar relacionada com uma diminuição da razão DQO / NTK. A eficiência alcançada pelo sistema para DQO (bruta/filtrada) e NTK foi de 88 e 52%, respectivamente. O sistema foi operado sem adição de fonte externa de carbono no reator anóxico. As análises de Biologia Molecular constataram a presença de Bactérias Oxidantes do Nitrito (Nitrospira), Bactérias Oxidantes de Amônia, Bactérias Desnitrifcantes e Anammox. / Removal of carbon and nitrogen was assessed through an innovative system of anaerobic , aerobic and anoxic reactors streaming series. Different operating conditions were tested for hydraulic retention time (HRT ) per reactor (anaerobic, aerobic and anoxic) in Phase 1 , Phase 2 , Phase 3 and Phase 4 which was 7h , 10h , 10h and 5h , respectively; and Dissolved Oxygen (DO) concentrations of 0.5-1.2 mg O2.L-1, 0.5-1.5 mg O2.L-1, 1.1-2.1 mg O2.L-1 and 1.1-2.5 mg O2.L-1, were tested. The anaerobic promoted an excellent removal of organic matter (85% ) and served as pretreatment to reduce the competition between heterotrophic and autotrophic nitrifying microorganisms in the aerobic reactor. The highest efficiency of nitrification was obtained when the concentration of DO was maintained between 1.1-2.5 mg O2.L-1. However, it was observed a decrease in the efficiency of denitrification, which can be related to a decrease in the ratio COD / TKN. The efficiency achieved by the system for COD and TKN was 88 and 52%, respectively. The system was operated without addition of external carbon source in the anoxic reactor. The molecular biology analysis found the presence of Oxidizers Nitrite Bacteria (Nitrospira), Oxidizers Ammonia Bacteria, Desnitrifcantes Bacteria and Anammox.

No description available.

Master of Science / Department of Grain Science and Industry / Keith C. Behnke / The effect of tracer particle size on the accuracy of measuring retention time inside the conditioner of a pellet mill was studied. Three experiments were conducted using tracers with different particle sizes. The control retention time was calculated using the hold-up capacity method, while retention times for treatments were calculated using the pulse-input method. In addition to the previously prepared tracers, crystalline salt and powder color dye were used as tracers in this study to represent small particle tracers. In experiment one, large, medium, and small tracers were used. The treatment with large particle size was closer to the control with differences around 1.5%. Conversely, using the tracer with small particle size resulted in larger differences, approximately 18%. Two tracers were used in experiment two, resulted in 33% difference between treatment and control using a small particle size tracer, and a 10% difference using a tracer with similar particle size to the main materials. A tracer similar in particle size to the materials flowing inside the conditioner was used in the third experiment in addition to the salt and dye. Statistical analyses for this experiment indicated that particle size affects the accuracy of retention time measurements. There was a significant difference (P<0.05) in the comparison between salt and red color dye in treatment two, while there was no significant difference (P>0.05) between them in treatment one (same particle size). Moreover, in another comparison of the differences between treatments and their related controls, there was significant difference (P<0.05). However, the P-value for the red dye comparison (0.0126) was higher than that of salt (0.0026), which adds density as another influential factor that affects retention time measurement.

Oriunda da etapa de destilação do caldo do caldo da cana-de-açúcar, a vinhaça é um subproduto da produção de etanol. Apesar de seu difundido uso na agricultura canavieira como fertirrigação, sua disposição no solo tem sido questionada quanto a possíveis riscos ambientais. Uma destinação alternativa à vinhaça e seu tratamento anaeróbio, considerado bastante atrativo haja vista a possibilidade de recuperação de energia na forma de biogás, sem interferir em suas qualidades como biofertilizante. Entre os sistemas de tratamento anaeróbios, os reatores de leito fixo têm sido amplamente utilizados devido à sua estabilidade operacional. A modelagem abrangente destes tipos reatores tende a ser complexa de forma que o estudo dos escoamentos em seu interior do reator é vital. Neste contexto, o objetivo deste trabalho foi analisar e simular numericamente a hidrodinâmica de reator de leito fixo de fluxo ascendente tipo APBR (anaerobic packed bed reactor). Em termos gerais, os resultados obtidos por simulação foram confrontados tanto com os correspondentes valores experimentais como com aqueles obtidos a partir dos modelos uniparamétricos comumente usados para representar reatores não ideais. Para tanto, foram empregados dados pré-existentes de ensaios hidrodinâmicos conduzidos no início e no final da operação, com biorreator alimentado com solução-traçador na forma de degrau a vazões de 4,6 L/dia e 2,3 L/dia. Foram considerados os modelos de dispersão de pequena e grande intensidade bem como o modelo de tanques agitados em série. Quanto às simulações numéricas, foi usado o software de CFD (fluidodinâmica computacional)COMSOL Multiphysics &reg; 4.3b.As curvas DTR obtidas via simulação e com base nos modelos para reatores não ideais foram confrontadas com as curvas obtidas experimentalmente. Para o reator operando com vazão de 2,3 L/dia, nenhum dos modelos propostos mostrou-se adequado quanto ao final da operação, em razão da incapacidade em representar o surgimento de picos de concentração que podem estar associados ao acúmulo de biomassa no interior do biorreator, mas também ao tipo de traçador utilizado para a realização do experimento. As demais curvas DTR sugerem que o reator em questão aproxima-se do tipo pistonado. O simulador CFD representou de forma bem adequada os dados experimentais em comparação com resultados obtidos a partir dos modelos para reatores não ideais. A simulação numérica de biorreatores para tratamento de efluentes mostrou-se, pois, capaz de fornecer informações mais detalhadas e precisas, geralmente úteis a engenharia do processo. Adicionalmente, foi implementado um simulador com base no método de Boltzmann em rede (lattice Boltzmann method, LBM) capaz de simular escoamento laminar bidimensional em regime permanente no interior de um canal. No escopo de uma linha de pesquisa em simulação LBM de biossistemas agroindustriais, trata-se de um esforço inicial quanto à simulação LBM da hidrodinâmica de biorreatores para tratamento de efluentes em geral. / Resulting from sugarcane juice distillation, vinasse is a by-product from ethanol industry. Despite its widespread use as fertirrigation at crops, direct deposition of vinasse into soils has raised environmental issues. Alternatively, it may undergo anaerobic treatment, which is very attractive in view of energy recovery as biogas while preserving vinasse quality as biofertilizer. Among anaerobic treatment systems, fixed-bed reactors come forward due to their operational stability. Their comprehensive modeling is prone to be complex so that the study of fluid flows prevailing inside is fundamental. Accordingly, the goal of this work was to numerically analyze and simulate the hydrodynamics within a particular upflow fixedbed reactor, namely anaerobic packed bed reactor. In general, results from simulations were compared with experimental counterparts as well as against results from well-known single-parameter models for non-ideal reactors. Existing data from hydrodynamic tests were then used, concerning operation at both start-up and shut-down and bioreactor stepwise feeding with tracer solution flow at 4,6 L/day and 2,3 L/day. Non-ideal reactor models comprised either low or high-dispersion together with continuous stirred-tank reactor model while COMSOL Multiphysics &reg; 4.3b CFD (computational fluid dynamics) software was employed for simulations. Retention time distribution (RTD) curves from simulations and from model calculations were compared to experimental ones. For operation at 2,3 L/day flow, no models proved to be suitable as far as shut-down operation is concerned, due to biomass accumulation inside the bioreactor. Remaining RTD curves suggested that reactor behavior resembles plug-flow type. Compared to non-ideal reactor models, CFD simulations proved to properly reproduce experimental data while being able to provide detailed and accurate information for process engineering towards effluent treatment. Furthermore, a numerical simulator was implemented as based on the lattice Boltzmann method (LBM) in order to deal with two-dimensional steady-state laminar flow inside a channel. As part of research work on LBM simulation of agroindustrial biosystems, aforesaid simulator contributed to LBM simulation of hydrodynamics within bioreactors for wastewater treatment in general.