Sludge digestion has gained importance in recent year because of increasing interest in energy recovery and public concern over the safety of land applied biosolids. Many new alternatives are being researched for reducing excess sludge production and for more energy production. With an increase in solids destruction, the nutrients that are contained in sludge especially nitrogen, are released to solution and can be recycled as part of filtrate or centrate stream. Nitrogen has gained importance because it has adverse effects on ecosystem's as well as human health. NH₄⁺, NO₂⁻, NO₃⁻-, and organic nitrogen are the different forms of nitrogen found in wastewater. While ammonia is toxic to aquatic life, any form of nitrogen can be utilized by cyanobacteria and result in eutrophication. NO₂/NO₃, if consumed by infants through water, can affect the oxygen uptake capability. Hence, removal of nitrogen from wastewater stream before discharging is important. The main purpose of this study was to evaluate the performance of the Cambi process, a thermophylic hydrolysis process used as a pre-treatment step prior to anaerobic digestion. Thermal hydrolysis, as a pre-treatment to anaerobic digestion increases the biological degradation of organic volatile solids and biogas production. The thermal hydrolysis process destroys pathogens and hydrolysis makes the sludge readily available for digestion, while at the same time facilitating a higher degree of separation of solid and liquid phases after digestion. Experiments were conducted in three phases for anaerobic digestion using the Cambi process as pre-treatment. The phases of study includes comparison of two temperatures for thermal hydrolysis (Cambi 150°C and Cambi 170°C), comparison of two solid retention times in anaerobic digestion (15 Day and 20 Day) and comparison of two mesophilic temperatures in anaerobic digestion (37°C and 42°C). Different experimental analyses were conducted for each phase, such as pH, bio-gas production, COD removal, VS destruction, nitrogen removal, odor and dewatering characteristics and the results are compared among all the phases. The second part of the study deals with aerobic digestion of anaerobically digested sludge for effective nitrogen removal and additional VS destruction, COD removal. An aerobic digester is operated downstream to anaerobic digester and is operated with aerobic/anoxic phase for nitrification and de-nitrification. The aerobic/anoxic phases are operated in time cycles which included 40minutes/20minutes, 20minutes/20minutes, full aeration, 10minutes/30minutes, and 12minutes/12minutes. Different time cycles are experimented and aerobic digester is optimized for effective nitrogen removal. 12minutes aerobic and 12minutes anoxic phase gave better nitrogen removal compared to all the cycles. Over all the aerobic digester gave about 92% ammonia removal, 70% VS destruction and 70% COD removal. The oxygen uptake rates (OUR's) in the aerobic digester are measured corresponding to maximum nitrogen removal. The OUR's are found to be close to 60 mg/L during maximum nitrogen removal. The effluent from both anaerobic digester and aerobic digester was collected and analyzed for dewatering capability, cake solids concentration and odor potential. / Master of Science

Because of the increasing trends in energy consumption and increased environmental awareness, greater focus has been placed on improvement and development of renewable energy sources. An already proven and accepted method is biogas production from anaerobic digestion at municipal wastewater treatment plants. In the waste water treatment process solid material and dissolved pollutants are separated from the water, forming a sludge. The sludge is separated from the process and stabilized during anaerobic digestion or aerobic aeration. Most often, mesophilic anaerobic digestion is used. Because of degradation by microorganisms, biogas with a high content of methane is formed during the digestion. To optimize the process different studies with co-digestion with sludge and other substrate have been made. It has been showed, in earlier research studies, that co-digestion with microalgae and sewage sludge results in a synergistic effect with increased biogas production. As the microalgae are microorganisms which use photosynthesis they contain stored energy from sun light. The stored energy will be available when the microalgae are digested in mesophilic conditions. In contrast to other biomass suitable for co-digestion microalgae have the advantage of being able to grow in waste water and reduce the pollutants in the water phase. Cultivation of microalgae will therefore not compete with the cultivation of food production and at the same time has the possibility to decrease the electricity- and heat consumption at the wastewater treatment plants. The aim of this study was to investigate how a possible synergetic effect between microalgae and sewage sludge effects the biogas production and the process stability. The microalgae was cultivated in municipal waste water from the WWTP in Umeå (Sweden) and the sludge was collected from the WWTP in Västerås (Sweden). The fermenters used was of the type DOLLY© and the active volume was 5 dm3. The temperature in the fermenters was kept at 37 °C and the study was divided into two periods. During the first period the hydraulic retention time was 15 days and the organic loading rate 2.4 g VS dm-3 d-1. During the second period the hydraulicretention time was kept at 10 days and the organic loading rate was 3.5 g VS dm-3 d-1. The result showed an increase with 54.6 % in methane production per reduced VS in the fermenter with co-digestion compared to the fermenter where only sludge was digested. Period one showed the highest increase. The result also showed a good process stability for both fermenters during the whole experiment. This study shows that there are reasons for continued investigations about co-digestion with microalgae and sewage sludge for an increased biogas production. / På grund av ökande el- och värmeförbrukning och ökat miljöengagemang har större fokus lagts på förbättring och utveckling av förnyelsebara källor för el- och värmeproduktion. En redan beprövad och accepterad metod för framställning av förnyelsebar energi är från biogasproduktion vid kommunala reningsverk. Vid rening av avloppsvatten avskiljs fasta partiklar och lösta föroreningar och bildar ett slam som separeras från vattnet. Slammet kan sedan stabiliseras anaerobt genom rötning eller aerobt genom luftning. En ofta använd metod vid konventionella reningsverk är mesofil anaerob rötning. Vid rötningen bryts material ner av mikroorganismer och genererar biogas som framförallt innehåller metan och koldioxid. För att optimera en sådan process och därmed kunna utvinna mer gas har det tidigare undersökts hur samrötning med olika material påverkar biogasproduktionen. Det har visat sig i forskningsförsök att samrötning med mikroalger och orötat blandslam ger en synergieffekt och mer biogas produceras. Mikroalgerna innehåller lagrad energi från solljus, då de är fotosyntesiserande organismer. Den lagrade energin har visat sig bli tillgänglig vid mesofil anaerob nedbrytning. Till skillnad från annan biomassa som undersökts för samrötning kan mikroalgerna odlas på avloppsreningsverken och fungera som en del av reningsprocessen då mikroalgerna tar upp näringsämnen ur vattnet de växer i. På det sättet undviks konkurrens om odlingsmark för livsmedel och så blir reningsprocessen på avloppsreningsverken mer el- och värmeeffektiv. Syftet med studien var att undersöka om eventuell synergieffekt mellan mikroalgerna och slammet påverkar biogasproduktionen och processtabiliteten vid mesofil anaerob rötning. Mikroalgerna som användes var odlade på mekaniskt renat spillvatten från Umeås reningsverk och slammet som användes hämtades ifrån Västerås reningsverk. Rötkamrarna som användes var av modellen DOLLY© med en aktiv volym på 5 dm3. Temperaturen i rötkamrarna hölls kring 37°C och studien var uppdelad i två perioder. Under period ett var den hydrauliska uppehållstiden 15 dygn och den organiska belastningen 2,4 g VS dm-3 d-1, medan period två hade en hydraulisk uppehållstid på 10 dygn och en organisk belastning på 3,5 g VS dm-3 d-1. Resultaten visade att metangasproduktionen per tillförd mängd organiskt material var lägre vid samrötning jämfört med rötning av enbart slam. Metangasproduktionen per reducerad mängd organiskt material ökade med upp till 54,6 % vid samrötningen jämfört med rötning av enbart slam. Period ett gav upphov till den största ökningen. Processen hölls stabil även vid inblandning av mikroalger, under både period ett och två. Studien visar att det finns ett underlag för fortsatta studier kring samrötning av mikroalger och slam för en ökad biogasproduktion.

The research describes an optimized waste-to-energy technology that utilizes agricultural residues for renewable energy, while reducing global methane emissions and maintaining food security. Laboratory-, pilot- and farm-scale anaerobic batch digesters were evaluated to enhance methane production from the anaerobic digestion of untreated rice straw in dry conditions using a novel co-digestion approach. An existing farm-scale biogas plant loaded with rice straw and piggery wastewater produced 295 MWh in a 422-day digestion cycle. The long acclimation period (approximately 200 days) and low biogas yield (181 LCH4/kgVS) could be enhanced by adding anaerobic sludge from the pulp and paper mill treatment process. In a laboratory setting, the addition of the sludge resulted in a specific methane yield of 335 LCH4/kgVS within 92 days. Hydrolysis of the straw was accelerated, and stable conditions were observed in terms of pH, alkalinity and nutrients. Similar improvements were demonstrated in pilot-scale digesters (1 m3) - a specific methane yield of 231 LCH4/kgVS was achieved in a 93-day digestion cycle with the sludge compared to 189 days without the sludge. Insufficient mixing within the pilot-scale system caused lower overall methane yields than those obtained in the laboratory-scale digesters. If sufficient mixing and mesophilic conditions are maintained within the farm-scale system, the co-digestion of rice straw with pig wastewater and paper mill sludge (wet weight ratio of 1:1.25:0.5) has the potential to reduce the retention time to three months (versus 422 days) and increase methane yields to over 300 LCH4/kgVS

A produção de hidrogênio e intermediários químicos por processo fermentativo é uma linha de pesquisa atual e que pode representar uma alternativa ao setor sucroenergético de melhoria na eficiência produtiva e energética dos processos. Nesse sentido, o objetivo deste trabalho foi avaliar o efeito do tempo de detenção hidráulica (TDH) na produção de hidrogênio e metabólitos solúveis a partir de três reatores anaeróbios de leito granular expandido (EGSB) mesofílicos (30°C) independentes (EGSB-10, EGSB-20 e EGSB-30), operando em diferentes concentrações afluentes (10, 20 e 30 g DQO L-1, respectivamente) e submetidos a tempos de detenção hidráulica de 24, 16, 8, 4, 2 e 1 h. No EGSB-10 o processo fermentativo não foi direcionado à produção de hidrogênio, sendo gerados, no entanto, compostos de interesse comercial (ácidos acético e propiônico) como metabólitos principais. O HAc produzido pela via homoacetogênica foi quantificado entre 29 e 41,3% do HAc total produzido no reator, justificando a ausência de hidrogênio nesse reator. No EGSB-20 a produção de hidrogênio ocorreu somente no TDH de 1 h (480 kg DQO m-3 d-1), sendo a PVH igual a 4,36 ± 1,68 L d-1 L-1 e o HY 0,34 ± 0,05 mmol H2 g-1 DQO. Já o EGSB-30 apresentou produção de hidrogênio nos TDH de 2 e 1 h, sendo a produção volumétrica de hidrogênio (PVH) máxima obtida no TDH de 1 h (8,77 ± 1,46 L d-1 L-1) e o maior rendimento de hidrogênio (HY) obtido no TDH de 2 h (0,33 ± 0,08 mmol H2 g-1 DQO). Em ambos os reatores (EGSB-20 e EGSB-30) a produção de hidrogênio foi favorecida pela elevação nas concentrações dos ácidos butírico e lático. A geração de ácido lático foi sugerida como fonte alternativa de carbono nesses reatores em condição de menor disponibilidade de carboidrato aos microrganismos, sendo, no entanto, uma via de baixo rendimento, o que justifica os valores reduzidos de HY. Os resultados obtidos evidenciaram a possibilidade de produção de hidrogênio e metabólitos solúveis por processo fermentativo a partir da vinhaça de cana-de-açúcar em reatores EGSB. / Hydrogen and chemical intermediates production by fermentative process is a current research line and may present an alternative to the sugarcane industry to improve the productivity and energy efficiency of the process. Moreover, this study aimed to evaluate the effect of hydraulic retention time (HRT) over the production of soluble metabolites in three independent mesophilic (30°C) expanded granular sludge bed (EGSB) reactors named EGSB-10, EGSB-20 and EGSB-30. These EGSB reactors were operated at different feed concentrations (10, 20 and 30 g DQO L-1) and hydraulic retention times of 24, 16, 8, 4, 2 e 1 h. In EGSB-10 the fermentation process was not directed towards hydrogen production. However, compounds of commercial interest (acetic and propionic acids) were produced as main metabolites. The acetic acid produced by the homoacetogenic pathway was quantified around 29 and 41.3% of total acetic acid, corroborating with the absence of hydrogen in this reactor. In EGSB-20 hydrogen production occurred only in HRT of 1 h. The hydrogen production rate (HPR) in this reactor was 4.36 ± 1.68 L d-1 L-1 and hydrogen yield (HY) was 0.34 ±0.05 mmol H2 g-1 COD. EGSB-30 presented hydrogen production in HRT of 2 and 1 h, with maximum HPR obtained in the HRT of 1 h (8.77 ± 1.46 L d-1 L-1). The highest HY was achieved in HRT of 2 h (0.33 ± 0.08 mmol H2 g-1 COD). In both rectors (EGSB-20 and EGSB-30), hydrogen production was favored by the increase of butyric and lactic acid concentrations. Lactic acid generation in the hydrogen production stages suggested the occurrence of an alternative carbon source in systems operated with carbohydrate limitation to the microorganisms. However, lactic acid generation is a metabolic route of low yield. As a consequence, HY was low in the evaluated experimental conditions. The production results evidenced the possibility of hydrogen and soluble metabolites production by fermentative process of sugarcane vinasse in EGSB reactors.

A cadeia sucroenergética tem uma grande influência para economia nacional. Ao longo da safra 2013/2014, a cadeia movimentou cerca de US$ 100 bilhões, sendo que somente o açúcar gerou uma arrecadação de cerca de US$ 5.55 bilhões as usinas. O Produto Interno Bruto chegou a US$ 43 bilhões, representando assim aproximadamente 2,0% do PIB Nacional. Todavia, o setor está atravessando uma crise econômica que foi potencializada pela queda no valor da saca de açúcar e por uma severa seca que atingiu em especial o estado de São Paulo. A diminuição de perdas se torna essencial em momentos de dificuldades e uma maneira de atingir esse objetivo é melhorando o monitoramento do processo. Nesse cenário, o presente pesquisa monitorou a degradação de sacarose ao coletar amostras em uma usina da região de Piracicaba-SP, associando como causador não somente as elevadas temperaturas, como outros fatores e medidas utilizadas pela indústria. Conforme esperado aumentou a concentração de sacarose ao longo do processo, iniciando com média de 137,69 g/L na moenda e finalizando com 812,91 g/L no açúcar que saiu do secador. Todavia também apresentou um aumento de açúcares redutores (182,38 g/L no caldo da moenda para 245,81 g/L no xarope), indicando a degradação de sacarose. Inclusive, percebe-se uma razão de inversão maior durante da evaporação do que no tratamento (0,46 e 0,28, respectivamente). A justificativa pode estar associada a possível queda no pH, a evidente utilização de maior quantidade de calor em especial no primeiro efeito, a um tempo de residência maior do que o normal nos evaporadores ou mesmo através da entrada de vapor nos corpos, sendo o último mais raro. Os outros parâmetros levantados da degradação térmica de sacarose, 5-hidroximetilfurfural, furfural e as melanoidinas apresentaram uma alta correlação em função da concentração de açúcares redutores (0,99 para o HMF, 0,98 furfural e 0,96 melanoidinas), confirmando a tendência de perdas da molécula de interesse. Também foram levantadas as populações de bactérias mesófilas totais, cujas presenças estão associadas com as condições sanitárias em que o alimento foi processado e fungos (bolores e leveduras) que também diminuem o valor do produto. O tratamento de caldo mostrou-se eficiente na diminuição dos micro-organismos. Considerando a média dos dois meses, a queda foi de 4,10 x 106 UFC/mL para 6,62x102 UFC/mL para bactérias mesófilas, já para fungos a redução foi de 1,40 x 104 UFC/mL para 1,80 x 101 UFC/mL. Todavia, as altas concentrações encontradas no início e no final (bactérias apresentaram em média 3,00 x 103 UFC/g no xarope e 2,26 x 103 UFC/g no açúcar do secador, enquanto que para os fungos foram encontrados 3,50 x 101 UFC/g no xarope e 1,49 x 103 UFCmL no açúcar do secador) são indicativos de descuidos com a assepsia, aproveitando a falta de exigência de qualidade no açúcar VHP. A alta concentração do caldo da moenda apresentou potencial de estar relacionado com a perda de sacarose. Por fim, ao avaliar a situação e considerando que investimento em equipamentos novos é algo fora da realidade financeira da usina, sugere-se trabalhar em aprimorar as operações realizadas dentro e fora da indústria para se evitar as perdas. / The sugar-energy industry chain has a great influence on the Brazilian economy. Along the 2013/2014 crop, the industry accounted for about US$ 100 billion, and sugar alone yielded about US$ 5.55 billion to sugar mills. The industry yielded US$ 43 billion, accounting for approximately 2,0% of the Brazilian GDP. Nevertheless, the industry is facing an economic crisis aggravated by the drop prices of sugar bag and a severe drought that hit particularly the state of São Paulo in Brazil. Minimizing losses becomes essential in times of difficulties and a way to achieve it is to improve process monitoring. In this scenario, the present project monitored sucrose degradation in samples collected at sugar mill in the region of Piracicaba-SP, associating the degradation to high temperatures as well as other factors and measures used by the mill. As expected, sucrose concentration increased throughout the process, starting with an average of 137,69 g/L at milling and finishing with 812,91 g/L in sugar out of the dryer. However, there was also an increase of reducing sugars (182,38 g/L in milling juice to 245,81 g/L in syrup), indicating sucrose degradation. There was a larger reversal rate during evaporation than in the treatment (0,46 and 0,28, respectively). This is possibly attributed to a pH decrease, an evident use of greater amount of heat in particular in the first effect, a longer time than normal in evaporators or even due to steam inlet into the bodies, which is rarer. The other parameters arising from sucrose thermal degradation, 5-hydroxymethylfurfural, furfural and melanoidins, showed a high correlation with the concentration of reducing sugars (0,99 for HMF, 0,98 for furfural and 0,96 for melanoidins), confirming the trend for loss of the molecule of interest. We also investigated the total populations of mesophilic bacteria, whose presence is associated with health conditions where the food was processed, as well as fungi (molds and yeasts), which also decreases the value of the final product, may produce mycotoxins. The syrup treatment was effective to reduce microorganisms. Considering the average, the population of mesophilic bacteria decrease from 4,10 x 106 cfu/mL to 6,62 x102 cfu/mL. For fungi, the reduction was 1,40 x 104 cfu/mL to 1,80 x 101 cfu/mL. However, the high concentrations found at the beginning and end (Bacteria on average 3,00 x 103 cfu/g in syrup and 2,26 x 103 cfu/g in sugar at the dryer. Fungi 3,50 x 101 cfu/g in syrup and 1,49 x 103 cfu/mL in sugar at the dryer) of the process are indicative of oversights with asepsis, using the lack of demand for quality VHP sugar. The high concentration of juice at milling showed potential to be related sucrose loss. Finally, assessing the scenario and considering that investment in new equipment is something out of the financial reality of the sugar mill, improving the operations inside and outside the mill to avoid losses is suggested.

A cadeia sucroenergética tem uma grande influência para economia nacional. Ao longo da safra 2013/2014, a cadeia movimentou cerca de US$ 100 bilhões, sendo que somente o açúcar gerou uma arrecadação de cerca de US$ 5.55 bilhões as usinas. O Produto Interno Bruto chegou a US$ 43 bilhões, representando assim aproximadamente 2,0% do PIB Nacional. Todavia, o setor está atravessando uma crise econômica que foi potencializada pela queda no valor da saca de açúcar e por uma severa seca que atingiu em especial o estado de São Paulo. A diminuição de perdas se torna essencial em momentos de dificuldades e uma maneira de atingir esse objetivo é melhorando o monitoramento do processo. Nesse cenário, o presente pesquisa monitorou a degradação de sacarose ao coletar amostras em uma usina da região de Piracicaba-SP, associando como causador não somente as elevadas temperaturas, como outros fatores e medidas utilizadas pela indústria. Conforme esperado aumentou a concentração de sacarose ao longo do processo, iniciando com média de 137,69 g/L na moenda e finalizando com 812,91 g/L no açúcar que saiu do secador. Todavia também apresentou um aumento de açúcares redutores (182,38 g/L no caldo da moenda para 245,81 g/L no xarope), indicando a degradação de sacarose. Inclusive, percebe-se uma razão de inversão maior durante da evaporação do que no tratamento (0,46 e 0,28, respectivamente). A justificativa pode estar associada a possível queda no pH, a evidente utilização de maior quantidade de calor em especial no primeiro efeito, a um tempo de residência maior do que o normal nos evaporadores ou mesmo através da entrada de vapor nos corpos, sendo o último mais raro. Os outros parâmetros levantados da degradação térmica de sacarose, 5-hidroximetilfurfural, furfural e as melanoidinas apresentaram uma alta correlação em função da concentração de açúcares redutores (0,99 para o HMF, 0,98 furfural e 0,96 melanoidinas), confirmando a tendência de perdas da molécula de interesse. Também foram levantadas as populações de bactérias mesófilas totais, cujas presenças estão associadas com as condições sanitárias em que o alimento foi processado e fungos (bolores e leveduras) que também diminuem o valor do produto. O tratamento de caldo mostrou-se eficiente na diminuição dos micro-organismos. Considerando a média dos dois meses, a queda foi de 4,10 x 106 UFC/mL para 6,62x102 UFC/mL para bactérias mesófilas, já para fungos a redução foi de 1,40 x 104 UFC/mL para 1,80 x 101 UFC/mL. Todavia, as altas concentrações encontradas no início e no final (bactérias apresentaram em média 3,00 x 103 UFC/g no xarope e 2,26 x 103 UFC/g no açúcar do secador, enquanto que para os fungos foram encontrados 3,50 x 101 UFC/g no xarope e 1,49 x 103 UFCmL no açúcar do secador) são indicativos de descuidos com a assepsia, aproveitando a falta de exigência de qualidade no açúcar VHP. A alta concentração do caldo da moenda apresentou potencial de estar relacionado com a perda de sacarose. Por fim, ao avaliar a situação e considerando que investimento em equipamentos novos é algo fora da realidade financeira da usina, sugere-se trabalhar em aprimorar as operações realizadas dentro e fora da indústria para se evitar as perdas. / The sugar-energy industry chain has a great influence on the Brazilian economy. Along the 2013/2014 crop, the industry accounted for about US$ 100 billion, and sugar alone yielded about US$ 5.55 billion to sugar mills. The industry yielded US$ 43 billion, accounting for approximately 2,0% of the Brazilian GDP. Nevertheless, the industry is facing an economic crisis aggravated by the drop prices of sugar bag and a severe drought that hit particularly the state of São Paulo in Brazil. Minimizing losses becomes essential in times of difficulties and a way to achieve it is to improve process monitoring. In this scenario, the present project monitored sucrose degradation in samples collected at sugar mill in the region of Piracicaba-SP, associating the degradation to high temperatures as well as other factors and measures used by the mill. As expected, sucrose concentration increased throughout the process, starting with an average of 137,69 g/L at milling and finishing with 812,91 g/L in sugar out of the dryer. However, there was also an increase of reducing sugars (182,38 g/L in milling juice to 245,81 g/L in syrup), indicating sucrose degradation. There was a larger reversal rate during evaporation than in the treatment (0,46 and 0,28, respectively). This is possibly attributed to a pH decrease, an evident use of greater amount of heat in particular in the first effect, a longer time than normal in evaporators or even due to steam inlet into the bodies, which is rarer. The other parameters arising from sucrose thermal degradation, 5-hydroxymethylfurfural, furfural and melanoidins, showed a high correlation with the concentration of reducing sugars (0,99 for HMF, 0,98 for furfural and 0,96 for melanoidins), confirming the trend for loss of the molecule of interest. We also investigated the total populations of mesophilic bacteria, whose presence is associated with health conditions where the food was processed, as well as fungi (molds and yeasts), which also decreases the value of the final product, may produce mycotoxins. The syrup treatment was effective to reduce microorganisms. Considering the average, the population of mesophilic bacteria decrease from 4,10 x 106 cfu/mL to 6,62 x102 cfu/mL. For fungi, the reduction was 1,40 x 104 cfu/mL to 1,80 x 101 cfu/mL. However, the high concentrations found at the beginning and end (Bacteria on average 3,00 x 103 cfu/g in syrup and 2,26 x 103 cfu/g in sugar at the dryer. Fungi 3,50 x 101 cfu/g in syrup and 1,49 x 103 cfu/mL in sugar at the dryer) of the process are indicative of oversights with asepsis, using the lack of demand for quality VHP sugar. The high concentration of juice at milling showed potential to be related sucrose loss. Finally, assessing the scenario and considering that investment in new equipment is something out of the financial reality of the sugar mill, improving the operations inside and outside the mill to avoid losses is suggested.

Ce travail de thèse présente l'optimisation d'une technologie de valorisation énergétique qui utilise des résidus agricoles pour la production d'énergies renouvelables, tout en réduisant les émissions mondiales de méthane et en garantissant la sécurité alimentaire. Des digesteurs anaérobies à l'échelle laboratoire, pilote et industrielle ont été évalués afin d'améliorer la production de méthane à partir de la digestion anaérobie de la paille de riz non traitée dans des conditions sèches en utilisant une approche nouvelle de co-digestion. Une installation de production biogaz à l'échelle d'une ferme chargée de paille de riz et d'eaux usées produites par une porcherie génère 295 MWh dans un cycle de digestion 422 jours. La période d'acclimatation relativement longue (environ 200 jours) et le faible rendement en biogaz (181 LCH4/kg MVS) pourraient être améliorées en ajoutant des boues anaérobies issues d'un procédé de traitement d'effluents de l'industrie papetière. Au laboratoire, l'ajout de la boue conduit à un rendement de méthane spécifique de 335 LCH4/kgMVS dans les 92 jours. L'hydrolyse de la paille a été accélérée, et des conditions stables ont été observées en termes de pH, d'alcalinité et de nutriments. Des améliorations similaires ont été démontrés dans des digesteurs à l'échelle pilote (1 m3) - un rendement de méthane spécifique de 231 LCH4/kgMVS a été obtenu dans un cycle de digestion à 93 jours avec de la boue comparativement à 189 jours sans la boue. Un mélange insuffisant dans le système à l'échelle pilote a causé des rendements de production de méthane inférieurs à ceux obtenus dans les digesteurs l'échelle du laboratoire. Si les conditions mésophiles et de mélange suffisantes sont maintenues dans le système à l'échelle industrielle, la co-digestion de la paille de riz avec des eaux usées produites par une porcherie et des boues issues d'un procédé de traitement d'effluent de l'industrie papetière (rapport poids humide de 1:1.25:0.5) a le potentiel de réduire le temps de rétention à trois mois (contre 422 jours) et d'augmenter les rendements de production de méthane à plus de 300 LCH4/kgMVS / The research describes an optimized waste-to-energy technology that utilizes agricultural residues for renewable energy, while reducing global methane emissions and maintaining food security. Laboratory-, pilot- and farm-scale anaerobic batch digesters were evaluated to enhance methane production from the anaerobic digestion of untreated rice straw in dry conditions using a novel co-digestion approach. An existing farm-scale biogas plant loaded with rice straw and piggery wastewater produced 295 MWh in a 422-day digestion cycle. The long acclimation period (approximately 200 days) and low biogas yield (181 LCH4/kgVS) could be enhanced by adding anaerobic sludge from the pulp and paper mill treatment process. In a laboratory setting, the addition of the sludge resulted in a specific methane yield of 335 LCH4/kgVS within 92 days. Hydrolysis of the straw was accelerated, and stable conditions were observed in terms of pH, alkalinity and nutrients. Similar improvements were demonstrated in pilot-scale digesters (1 m3) – a specific methane yield of 231 LCH4/kgVS was achieved in a 93-day digestion cycle with the sludge compared to 189 days without the sludge. Insufficient mixing within the pilot-scale system caused lower overall methane yields than those obtained in the laboratory-scale digesters. If sufficient mixing and mesophilic conditions are maintained within the farm-scale system, the co-digestion of rice straw with pig wastewater and paper mill sludge (wet weight ratio of 1:1.25:0.5) has the potential to reduce the retention time to three months (versus 422 days) and increase methane yields to over 300 LCH4/kgVS

Submitted by Livia Mello (liviacmello@yahoo.com.br) on 2016-09-16T13:22:34Z No. of bitstreams: 1 DissMB.pdf: 3232973 bytes, checksum: 2ca9f79e6634a4d39d6cb45bd3047475 (MD5) / Approved for entry into archive by Marina Freitas (marinapf@ufscar.br) on 2016-09-21T18:31:52Z (GMT) No. of bitstreams: 1 DissMB.pdf: 3232973 bytes, checksum: 2ca9f79e6634a4d39d6cb45bd3047475 (MD5) / Approved for entry into archive by Marina Freitas (marinapf@ufscar.br) on 2016-09-21T18:31:56Z (GMT) No. of bitstreams: 1 DissMB.pdf: 3232973 bytes, checksum: 2ca9f79e6634a4d39d6cb45bd3047475 (MD5) / Made available in DSpace on 2016-09-21T18:32:00Z (GMT). No. of bitstreams: 1 DissMB.pdf: 3232973 bytes, checksum: 2ca9f79e6634a4d39d6cb45bd3047475 (MD5) Previous issue date: 2014-03-28 / Não recebi financiamento / This work aimed to evaluated the biological hydrogen production using crude glycerol as feedstock in two anaerobic reactors: (1) anaerobic fluidized bed reactor (AFBR), that allows high mass transfer, and (2) an expanded granular sludge blanket reactor, that can used with high efficiency even at high organic loading. In the AFBR, it was evaluated the influence of HRT (14, 12, 10, 8, 6, 4, 2 and 1 hour) in the hydrogen production using crude glycerol as feedstock at 5 g.L-1 and expanded clay as support material. In the EGSB, the HRT varied from 24 to 1 hour, it was used the same feedstock as that used in the AFBR. The reactors were maintained at controlled temperature at 30°C. The noculum for AFBR and EGSB was granular sludge taken from UASB reactor treating poultry slaughterhouse that was previously submitted to heat treatment. In the AFBR, the hydrogen production rate (HPR) increased from 0.08 to 0.73L.h-1.L -1 with the decrease at HRT from 14 to 1 hour, respectively. The hydrogen yield (HY) did not presented the same trend and remained almost unchanged (0.62, 0.76, 0.73, 0.75, 0.60, 0.58, 0.69, 0.85 molH2.mol-1glycerol). For this reactor, the main byproducts were 1,3-propanediol (1,3-PD), ethanol, acetic, butyric and propionic acid. The highest 1,3-PD (1,230 mg.L-1), ethanol (723 mg.L-1), acetic acid (204 mg.L-1), propionic acid (759 mg.L-1) and butyric acid (324 mg.L-1) concentration occurred at HRT of 6, 14, 8, 2, 6 hours, respectively. In the EGSB, the HPR and the HY presented the same trend: HPR increased from 0.018 to 1.708 L.h-1.L-1 and HY increased from 0.19 to 2.87 molH2.mol-1glycerol with the decrease in the HRT from 14 to 1 hour. For both reactors, the AFBR and the EGSB,the highest HPR and HY occurred at HRT of 1 hour. As well as for the AFBR, the main byproducts quantified in the EGSB were 1,3-propanediol (1,3-PD), ethanol, acetic, butyric and propionic acid. The highest 1,3-PD (1,606 mg.L -1), ethanol (400 mg.L-1), acetic acid (219 mg.L-1), propionic acid (1,075 mg.L-1) and butyric acid (248 mg.L-1) concentration occurred at HRT of 16, 12, 16, 8, 20 hours, respectively. / O presente estudo avaliou a produção biológica de hidrogênio utilizando glicerol bruto como matéria-prima em dois reatores anaeróbios: (1) reator anaeróbio de leito fluidizado (RALF), que possibilita elevada transferência de massa, e (2) um reator de leito granular expandido (EGSB), que pode apresentar alta eficiência mesmo quando aplicadas elevadas cargas orgânicas. No RALF, foi avaliada a influência do TDH (14, 12, 10, 8, 6, 4, 2 e 1 hora) na produção de hidrogênio utilizando o glicerol bruto como matéria-prima na concentração de 5 g.L-1 e argila expandida como material de suporte. No EGSB, o TDH estudado variou de 24 a 1 hora, e o substrato e a concentração foram as mesmas que os utilizadas no RALF. Os reatores foram mantidos em temperatura controlada de 30 °C. O inóculo para ambos os reatores, RALF e EGSB, foi lodo granular de reator UASB utilizado no tratamento de água residuária de abatedouro de aves, que foi previamente submetido ao tratamento térmico. No RALF, a taxa de produção de hidrogênio (HPR) aumentou de 0,08 para 0,73L.h-1.L- 1 com a diminuição do TDH de 14 para 1 hora, respectivamente. O rendimento de hidrogênio (HY) não apresentou a mesma tendência e manteve-se praticamente inalterado (0,62; 0,76; 0,73; 0,75; 0,60; 0,58; 0,69 e 0,85 molH2.mol-1glicerol) . Para este reator, os principais metabólitos foram 1,3-propanodiol (1,3-PD), etanol, ácido acético, butírico e propiônico. A maior concentração de 1,3- PD (1.230 mg.l-1), etanol (723 mg.L -1 ), ácido acético (204 mg.L-1), ácido propiônico (759 mg.L-1) e ácido butírico (324 mg.L-1) foi observada nos TDH de 6, 14, 8, 2, 6 horas, respectivamente. No EGSB, o HPR e HY apresentaram a mesma tendência: o HPR aumentou de 0,018-1,708 L.h-1.L-1 e o HY aumentou de 0,19-2,87 molH2.mol-1 glicerol com a diminuição do TDH de 14 para 1 hora. Para ambos os reatores, o RALF e o EGSB, a maior HPR e o maior HY foram observados no TDH de 1 hora. Assim como para o RALF, os principais metabólitos quantificados no EGSB foram 1,3- propanodiol (1,3-PD), etanol, ácido acético, ácido butírico e ácido propiônico. A maior concentração de 1,3- PD (1.606 mg.L-1), etanol (400 mg.L -1), ácido acético (219 mg.L-1), ácido propiônico (1.07 mg.L -1) e ácido butírico (248 mg.L -1) foi observada no TDH de 16, 12, 16, 8 e 20 horas, respectivamente.

The use of mesophilic anaerobic digestion for treatment of organic wastes is a growing biotechnology for sustainable energy supply. Ammonia inhibition is a major problem in anaerobic digestion mainly when digestion of nitrogen-rich substrates such as livestock wastes and manure occurs. This paper provides a summary of research conducted on ammonia inhibition of the anaerobic process. An experiment with mesophilic digestions of swine manure was conducted in single unit reactors, which were controlled under different ammonia concentrations by addition of NH4Cl in different amounts. From the experimental results, it was shown that NH4Cl could be an effective chemical agent for removing foam and scum in the digester. Methane production was decreased with the increasing NH4Cl addition until a collapse was observed between 11.2 g NH4+-N/l and 13.2 g NH4+-N/l. Contrary to the findings in thermophilic digestion, a dysfunction of acidogenesis was also observed since both gas and methane production was delayed with increasing NH4Cl addition. These findings suggest different ammonia inhibition principles in mesophilic and thermophilic digestion. It was further indicated that methanogenesis could produce a high percentage of methane although gas production was inhibited.

Submitted by Neusa Fagundes (neusa.fagundes@unioeste.br) on 2018-09-10T17:43:56Z No. of bitstreams: 2 Santiago_Pereira Neto2018.pdf: 1174069 bytes, checksum: 82494df7c5196d52518cc45a8c47da33 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2018-09-10T17:43:56Z (GMT). No. of bitstreams: 2 Santiago_Pereira Neto2018.pdf: 1174069 bytes, checksum: 82494df7c5196d52518cc45a8c47da33 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2018-02-16 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / In this study, the influence of the load progression was evaluated, using poultry litter in reactors that had already been operating with swine waste, in relation to physical-chemical and operational parameters. In order to evaluate the solids content of the chicken litter, CSTR reactors were used with a useful volume of 12 L, the control reactor (R1) with only swine manure and the reactor for co-digestion swine and poultry litter (R2). It was possible to notice that the increase in methane productivity was up to 56% in the VOCs of 2.1 and 3.0 kgSV.m-3.d-1 based on the volatile solids (SV) of the chicken bed added. Average methane yield at R2 reached 0.54 LN CH4. Loor-1. d-1 for VOCs of 3.0 and 4.5 kgSV.m-3d-1. The values of AI/P and short-chain organic acids changed from 3.6-3 and 4.5 kgSV.m-3.d-1 (values close to 0.1 to 0.4), but the pH of the system remained stable due to the alkalinity of the swine manure. The total solids content (ST) at which the reactor was operated was 11.7% (m.v-1), during which time a large quantity of foam was formed in the system, which led to operational problems due to the reactor’s overload. In view of the limitation of many reactors operating with higher solids contents, CSTR is an important option for anaerobic co-digestion of a poultry litter and swine manure, two residues of relevant agroindustrial chains in Brazil and in the world. / Nesse estudo foi avaliada a influência da progressão de carga, utilizando cama de frango em reatores que já operam com dejeto suíno, em relação a parâmetros físico-químicos e operacionais. Tendo em vista o teor de sólidos da cama de frango, utilizaram-se reatores do modelo CSTR com volume útil de 12 L, o reator controle (R1) somente com dejeto suíno e o reator para codigestão dejeto suíno e cama de frango (R2). Foi possível notar que o incremento na produtividade de metano foi de até 56% nas COVs de 2,1 e 3,0 kgSV.m-3.d-1 com base nos sólidos voláteis (SV) da cama de frango adicionados. A produtividade média de metano em R2 alcançou 0,54 LN CH4.Lreator-1. d-1 para as COVs de 3,0 e 4,5 kgSV.m-3.d-1. Os valores de AI/P e ácidos orgânicos de cadeia curta sofreram alterações a partir da carga 3,6 3,0 e 4,5 kgSV.m-3.d-1 (de valores próximo a 0,1 para 0,4), mas o pH do sistema se manteve estável devido à alcalinidade do dejeto de suíno. O teor de sólidos totais (ST) limite em que o reator foi operado foi de 11,7% (m.v-1). Nesse período houve formação de grande quantidade de escuma no sistema, o que levou a problemas operacionais devido à sobrecarga do reator. Tendo em vista a limitação de muitos reatores em operar com teores de sólidos maiores, o CSTR é uma opção importante para a codigestão anaeróbia da cama de frango e dejeto de suíno, dois resíduos de cadeias agroindustriais relevantes no Brasil e no mundo.