O objetivo desse trabalho foi o de avaliar o desempenho de um reator anaeróbio híbrido de alta taxa (AHHR), contendo biomassa imobilizada em leito ordenado, alimentado com a fração líquida de esterco bovino, na produção de biogás. No estudo, foi utilizado um reator anaeróbio de fluxo ascendente de 12,4 L de volume total (9,2 L de volume útil) com leito ordenado composto por hastes de espuma de poliuretano (PU). O leito ordenado utilizado possuía 32 hastes de espuma de 1,25 cm2 de seção com 50,0 cm de comprimento, posicionadas verticalmente no interior do reator. A alimentação do reator e a recirculação foram realizadas por meio de bombas dosadoras de diafragma. O reator operou na faixa mesofílica de temperatura (de 20 a 40 &#176C) sem a utilização de mecanismos de controle de temperatura. Foram testadas 7 condições operacionais diferentes, variando o tempo de detenção hidráulica (TDH), carga orgânica volumétrica (COV) aplicada e a utilização de recirculação interna. Para cada fase operacional, foram avaliadas a remoção de matéria orgânica e a produção de biogás. O sistema apresentou elevada remoção de matéria orgânica operando com TDH de 3 e 1d, respectivamente, com valores médios de remoção de DQO de 79 &#37 e 71 &#37. O biogás produzido pelo reator apresentou concentração de metano de 57,6 ± 0,5 &#37 e não foi detectada a presença de sulfeto. A maior produção média de metano foi de 1,676 L CH4/d, obtida com COV de 20 kg DQO/m3.d e TDH de 1d, enquanto a maior produção relativa de metano foi de 0,023 L CH4./ g SV.d, obtida com COV de 5 kg DQO/m3.d e TDH de 1d e recirculação. A relação entre alcalinidade intermediária e parcial teve valor médio de 0,32, oscilando na maior parte do tempo entre 0,27 e 0,33, indicando a estabilidade do processo de digestão anaeróbia. Os resultados obtidos indicaram o potencial satisfatório do AHHR para a remoção de matéria orgânica e produção de biogás a partir da fração líquida do esterco bovino nas condições operacionais testadas na pesquisa. / This study aimed at evaluating the biogas production for electricity generation performance of an anaerobic high-rate hybrid reactor (AHHR), containing immobilized biomass in structured-bed, fed with the liquid fraction of cattle manure. In this study, it was used an upflow 12,4 L anaerobic reactor (9,2 L working volume) with structuredbed composed by 32 PU foam stripes (1,25 cm2 cross section and 500 mm length) vertically fixed inside the reactor. The reactor feeding and internal recirculation was made by diaphragm metering pumps. The reactor operated at mesophilic temperature (20 - 40 &#176C) without temperature control system. Different operating conditions were tested (7 stages), changing hydraulic retention time (HRT), organic loading rate (OLR) and recirculation use. COD removal and biogas production were evaluated for each operational condition. The system resulted in high COD removal operating with HRT of 3 and 1d, respectively, with average COD removal of 79 &#37 and 71 &#37. Produced biogas had 57,6 ± 0,5 &#37 of methane and no sulfide. The highest average volumetric methane production was 1,676 L CH4, obtained with OLR of 20 kg COD/m3.d and 1d HRT, and the highest methane yield was 0,023 L CH4/ g VS obtained with OLR of 5 kg COD/m3.d, 1d HRT and recirculation. The intermediate and partial alkalinity relation had an average value of 0,32, varying most of the time between 0,27 and 0,33, indicating the anaerobic digestion process stability. The results indicated the decent COD removal and biogas production using the AHHR fed with the liquid fraction of cattle manure at the operation conditions used in this study.

No Brasil, apesar do desenvolvimento mais acentuado na suinocultura, é na bovinocultura que se encontra o maior potencial para a digestão anaeróbia no tratamento de dejetos animais. O último Censo Agropecuário revelou uma tendência de concentração da criação de bovinos de leite e corte, além da migração para a região amazônica, resultando em maior pressão sobre a floresta nativa. Também evidenciou que a maior parte dos dejetos ainda é utilizada in natura. O aproveitamento em biodigestores dos dejetos coletáveis de um rebanho com aproximadamente 200 milhões de bovinos poderia resultar na auto-suficiência energética do setor agropecuário brasileiro. Os principais desafios encontram-se na dispersão destes resíduos e num entendimento limitado dos benefícios dos subprodutos da biodigestão, em especial o valor econômico e ambiental do biofertilizante. As ferramentas disponíveis costumam tratar separadamente as duas vertentes, uma energética associada ao biogás e a outra agronômica associada ao biofertilizante. Este trabalho apresenta uma abordagem original deste problema através do desenvolvimento de uma ferramenta que trata estas vertentes simultaneamente, através da simulação da dinâmica dos nutrientes no sistema solo-planta-animal. Partiu-se do modelo Century, tornando dinâmicos os parâmetros dos seus módulos GRAZING e OMAD (pastejo e adição de matéria orgânica, respectivamente). Para isso foram incorporadas rotinas que simulam o manejo dos animais, nutrição animal, manejo dos dejetos e digestão anaeróbia. O Modelo Century Modificado (MCM) foi capaz de simular a composição dos dejetos (carbono, nitrogênio e lignina), perda de nitrogênio no solo em função de diversas taxas de ocupação, o consumo dos animais em função da qualidade da espécie forrageira, entre muitos outros parâmetros. O MCM foi aplicado ao pastejo de braquiária por bovinos na zona da mata mineira (Coronel Pacheco), no período após a remoção da mata atlântica e conversão em pastagem e revelou que a biodigestão dos dejetos pode contribuir para a sustentabilidade econômica e ambiental dos bovinocultores de diversas formas. A redução das perdas de nitrogênio resulta em menor demanda de adubos nitrogenados e aumenta os benefícios e competitividade dos biodigestores. Na comparação com o manejo tradicional, verifica-se que os compartimentos ativos de C e N são fortemente impactados pela estratégia de manejo dos dejetos. O uso do MCM revela também que a digestão anaeróbia pode viabilizar maiores taxas de ocupação e a suplementação alimentar pode interferir com a estratégia de manejo dos dejetos. O modelo pode auxiliar em análises de emissões de gases de efeito-estufa, inclusive emissões entéricas, por incorporar a dinâmica de carbono em todos os componentes do sistema: solo, plantas e animais. Com parâmetros adequadamente escolhidos pode-se conduzir análises para qualquer região, não se limitando à região alvo do trabalho. / In Brazil, despite greater development with swine manure, anaerobic digestion finds its greatest potential in cattle sector when manure treatment is concerned. The last Livestock and Agriculture Census revealed a clear trend towards more concentrated milk and beef cattle breeding, besides migration to the Amazon Region, leading to higher pressure over the native forest. Also showed that manure is mainly used in natura. Collectable manure treatment with biodigesters considering a herd of approximately 200 million cattle heads would allow Brazilian livestock and agriculture sectors to be energetically self-sustainable. Main challenges are dispersion of manure availability and limited understanding of benefits associated with anaerobic digestion byproducts, especially digestate economic and environmental valuation. Available tools normally focus on two branches separately, one directed to energy associated to biogas and the other, agronomic, linked to the digestate. This thesis presents an original approach to this problem through the development of a tool that addresses these two branches simultaneously through the simulation of nutrients dynamics in soil-plant-animal system. Starting point was the Century Model, turning GRAZING and OMAD modules parameters into dynamic variables. New routines were developed and incorporated aimed at simulating herd evolution, animal nutrition, manure management and anaerobic digestion. The Modified Century Model (MCM) successfully simulated manure composition (carbon, nitrogen and lignin), soil nitrogen losses for different animal occupation rates and intake versus feed characteristics, among many other parameters. MCM was applied to brachiaria grazing by cattle at the zona da mata mineira (Coronel Pacheco) after Atlantic forest removal and revealed that anaerobic digestion can contribute to economic, energetic and environmental sustainability of cattle operations in many ways. Reduction of nitrogen losses leads to lower demand of nitrogenated fertilizers and increases the benefits and competitiveness of biodigestors. In comparison to traditional management, C and N active pools are strongly impacted by manure treatment strategies. MCM also shows that anaerobic digestion can lead to denser animal occupation rates and that supplements can impact manure management strategy. MCM can support greenhouse gases emission analysis, including enteric emissions, considering carbon dynamics in all related elements: soil, plants and animals. With parameters adequately chosen analysis can be developed for any region, not limited to the targeted region of this thesis.

No Brasil, apesar do desenvolvimento mais acentuado na suinocultura, é na bovinocultura que se encontra o maior potencial para a digestão anaeróbia no tratamento de dejetos animais. O último Censo Agropecuário revelou uma tendência de concentração da criação de bovinos de leite e corte, além da migração para a região amazônica, resultando em maior pressão sobre a floresta nativa. Também evidenciou que a maior parte dos dejetos ainda é utilizada in natura. O aproveitamento em biodigestores dos dejetos coletáveis de um rebanho com aproximadamente 200 milhões de bovinos poderia resultar na auto-suficiência energética do setor agropecuário brasileiro. Os principais desafios encontram-se na dispersão destes resíduos e num entendimento limitado dos benefícios dos subprodutos da biodigestão, em especial o valor econômico e ambiental do biofertilizante. As ferramentas disponíveis costumam tratar separadamente as duas vertentes, uma energética associada ao biogás e a outra agronômica associada ao biofertilizante. Este trabalho apresenta uma abordagem original deste problema através do desenvolvimento de uma ferramenta que trata estas vertentes simultaneamente, através da simulação da dinâmica dos nutrientes no sistema solo-planta-animal. Partiu-se do modelo Century, tornando dinâmicos os parâmetros dos seus módulos GRAZING e OMAD (pastejo e adição de matéria orgânica, respectivamente). Para isso foram incorporadas rotinas que simulam o manejo dos animais, nutrição animal, manejo dos dejetos e digestão anaeróbia. O Modelo Century Modificado (MCM) foi capaz de simular a composição dos dejetos (carbono, nitrogênio e lignina), perda de nitrogênio no solo em função de diversas taxas de ocupação, o consumo dos animais em função da qualidade da espécie forrageira, entre muitos outros parâmetros. O MCM foi aplicado ao pastejo de braquiária por bovinos na zona da mata mineira (Coronel Pacheco), no período após a remoção da mata atlântica e conversão em pastagem e revelou que a biodigestão dos dejetos pode contribuir para a sustentabilidade econômica e ambiental dos bovinocultores de diversas formas. A redução das perdas de nitrogênio resulta em menor demanda de adubos nitrogenados e aumenta os benefícios e competitividade dos biodigestores. Na comparação com o manejo tradicional, verifica-se que os compartimentos ativos de C e N são fortemente impactados pela estratégia de manejo dos dejetos. O uso do MCM revela também que a digestão anaeróbia pode viabilizar maiores taxas de ocupação e a suplementação alimentar pode interferir com a estratégia de manejo dos dejetos. O modelo pode auxiliar em análises de emissões de gases de efeito-estufa, inclusive emissões entéricas, por incorporar a dinâmica de carbono em todos os componentes do sistema: solo, plantas e animais. Com parâmetros adequadamente escolhidos pode-se conduzir análises para qualquer região, não se limitando à região alvo do trabalho. / In Brazil, despite greater development with swine manure, anaerobic digestion finds its greatest potential in cattle sector when manure treatment is concerned. The last Livestock and Agriculture Census revealed a clear trend towards more concentrated milk and beef cattle breeding, besides migration to the Amazon Region, leading to higher pressure over the native forest. Also showed that manure is mainly used in natura. Collectable manure treatment with biodigesters considering a herd of approximately 200 million cattle heads would allow Brazilian livestock and agriculture sectors to be energetically self-sustainable. Main challenges are dispersion of manure availability and limited understanding of benefits associated with anaerobic digestion byproducts, especially digestate economic and environmental valuation. Available tools normally focus on two branches separately, one directed to energy associated to biogas and the other, agronomic, linked to the digestate. This thesis presents an original approach to this problem through the development of a tool that addresses these two branches simultaneously through the simulation of nutrients dynamics in soil-plant-animal system. Starting point was the Century Model, turning GRAZING and OMAD modules parameters into dynamic variables. New routines were developed and incorporated aimed at simulating herd evolution, animal nutrition, manure management and anaerobic digestion. The Modified Century Model (MCM) successfully simulated manure composition (carbon, nitrogen and lignin), soil nitrogen losses for different animal occupation rates and intake versus feed characteristics, among many other parameters. MCM was applied to brachiaria grazing by cattle at the zona da mata mineira (Coronel Pacheco) after Atlantic forest removal and revealed that anaerobic digestion can contribute to economic, energetic and environmental sustainability of cattle operations in many ways. Reduction of nitrogen losses leads to lower demand of nitrogenated fertilizers and increases the benefits and competitiveness of biodigestors. In comparison to traditional management, C and N active pools are strongly impacted by manure treatment strategies. MCM also shows that anaerobic digestion can lead to denser animal occupation rates and that supplements can impact manure management strategy. MCM can support greenhouse gases emission analysis, including enteric emissions, considering carbon dynamics in all related elements: soil, plants and animals. With parameters adequately chosen analysis can be developed for any region, not limited to the targeted region of this thesis.

The energy sources and oil derivatives necessities have increased over the last years as well the mitigation of greenhouse gases (GHGs) emissions. These concepts provided an increase on the use of residual lignocellulosic biomass as a renewable source for the production of biofuels and chemical products. In this study, the cattle manure was chosen as a biomass source considering their high availability, as well as could be a major environmental pollutant residue when not treated properly. Thus, we propose to produce and characterize the bio-oil and biochar through of micro and macroscale pyrolysis. The work was divided into two parts: biomass characterization and characterization of the pyrolysis products. The cattle manure biomass presented 9.65% moisture after drying over ambient temperature, 38.86% ash, 48.29% volatile matter and 3.20% fixed carbon; high oxygen content (34.19%) and carbon (21.66%) by elemental analysis; and low lignin content (6.09%) in comparison with the hemicellulose (18.24%) and cellulose (14.24%). The thermogravimetric curve showed four mass loss stage between 25- 900 o C and a residual mass content of 39.58%; infrared analysis showed characteristic bands of alcohols, phenols, carboxylic acids, nitrogenous compounds and aliphatic groups. Concerning of bio-oils characterization, presented as highly oxygenated liquid with predominant compounds from the alcohols, phenols and carboxylic acid in micro and macroscale. Due to the high calorific value of bio-oils (21.35–27.10 MJ kg -1 ), can be used as biofuel. Biochars showed yields between 62.5% and 39.1%, the increase on pyrolysis temperature has provided an increase in ash and pH values, as also decreasing in proportion H/C, indicating increase on aromaticity of biochar the 600 ºC, also evidenced by the infrared analysis. / O aumento da necessidade energética e de produtos derivados do petróleo, bem como a necessidade de mitigação das emissões de gases de efeito estufa (GEE), têm proporcionado um crescimento em pesquisas sobre a utilização da biomassa lignocelulósica residual como fonte renovável para a obtenção de biocombustíveis e produtos químicos de maior valor agregado. Diante destas problemáticas, o esterco bovino foi escolhido como fonte de biomassa para este estudo devido a sua alta disponibilidade, além de ser um resíduo que quando não tratado adequadamente pode se tornar um grande poluente ambiental. Desta forma, este trabalho propõe produzir e caracterizar o bio-óleo e o biocarvão obtidos a partir da biomassa de esterco bovino através dos processos de pirólise em micro e macroescala. O trabalho foi dividido em duas partes: caracterização da biomassa e caracterização dos produtos das pirólises. A biomassa de esterco bovino apresentou 9,65% de umidade, 38,86% de cinzas e 51,49% de matéria orgânica; alto teor de oxigênio (34,19%) e carbono (21,66%); baixo teor de lignina (6,09%) em comparação com a hemicelulose (18,24%) e a celulose (14,24%). A curva termogravimétrica exibiu quatro estágios de perda de massa entre 25-900 o C e um teor de massa residual de 39,58%; a análise do infravermelho apresentou bandas características de álcoois, fenóis, ácidos carboxílicos, compostos nitrogenados e grupos alifáticos. Com relação à caracterização do bio-óleo, apresentou-se como líquido altamente oxigenado com predominância de compostos pertencentes às classes de fenóis, álcoois e ácidos carboxílicos em micro e macroescala. Devido ao alto valor do poder calorífico dos bio-óleos (21,35–27,10 MJ kg -1 ) pode-se cogitar a possibilidade de seu uso como biocombustível. Quanto ao biocarvão, mostrou rendimento que variou de 62,5% a 39,1%; o aumento da temperatura de pirólise aumentou o teor de cinzas e concomitantemente os valores de pH, bem como reduções em razões H/C, indicando um aumento do grau de aromaticidade do biocarvão formado a 600 ºC, fato também evidenciado pela análise de infravermelho.

Made available in DSpace on 2017-07-10T17:59:32Z (GMT). No. of bitstreams: 1 Jesse Siqueira.pdf: 809003 bytes, checksum: 6021d4aac82f4c76ae84284b8bb770cd (MD5) Previous issue date: 2012-12-07 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / In seeking to reduce dependence on fossil fuels, alternative energy sources and less environmental impact has been widely studied, biofuels. Among them, we highlight the biodiesel and biogas. The increased production of biodiesel to meet with Brazilian legislation, invariably leads to an increase in the supply of a co-product called crude glycerin. With a generation of about 10% of the total volume of biodiesel produced large amounts of glycerin are generated annually, however, the costs for purification of the co-product are high. It is necessary to note its correct disposal, since it has high organic load and its improper disposal could mean major environmental impacts. One way is the biodigestion with other organic waste such as cattle manure. Its high carbon biodegradable can be used in co-digestion with cattle manure as a supplement in the production of biogas. The addition of different concentrations of crude glycerin (2%, 4% and 6% m / m) was used as a supplement in anaerobic digestion co-dairy cattle manure in laboratory batch digesters (3.5 L working volume) . The digesters were operated at mesophilic conditions (30 ° C), with hydraulic retention time (HRT) of 30 days. It was analyzed the total solids (TS), volatile solids (VS) and chemical oxygen demand (COD) to determine the process efficiency in the removal of organic matter and its effect on biogas production. The addition of 4% glycerin resulted in higher production of biogas, about 9307 ml. The COD removal efficiency decreased with addition of glycerin, with the greatest reduction in control treatment, 68%. In other treatments increased by 90% and 118% for treatments Gli4% and Gli6% respectively. The VS reductions for the treatments Gli0%, Gli2% Gli4% and Gli6% were 18.17%, 61.60%, 24.36% and 44.83% for the respective treatments. / Em busca de se diminuir a dependência do uso de combustíveis fósseis, fontes alternativas e de menor impacto ambiental tem sido amplamente estudadas, os biocombustíveis. Dentre eles, destacam-se o biodiesel e o biogás. O aumento da produção de biodiesel a fim de atender à legislação brasileira, invariavelmente acarreta um aumento na oferta de um co-produto chamado glicerina bruta. Com uma geração de cerca de 10% do volume total de biodiesel produzido, grandes quantidades de glicerina são geradas anualmente, sendo que os custos para a purificação são elevados. São necessárias formas de se destinar corretamente esse co-produto, já que apresentam elevada carga orgânica e sua disposição inadequada poderia significar grandes impactos ambientais. Uma forma é a biodigestão juntamente com outro resíduo orgânico, como os dejetos bovinos. Seu teor elevado de carbono biodegradável pode ser aproveitado na co-digestão com dejetos bovinos como um suplemento na produção de biogás. A adição de diferentes concentrações de glicerina bruta (0%, 2%, 4% e 6% m/m) foi utilizada como suplemento na co-digestão anaeróbia de dejetos bovinos de leite, em biodigestores laboratoriais de batelada ( 3,5 L de volume útil). Os biodigestores foram operados em condições mesofílicas (30º C), com tempo de retenção hidráulica (TRH) de 30 dias. Foram analisados os sólidos totais (ST), sólidos voláteis (SV) e demanda química de oxigênio ( DQO) a fim de determinar a eficiência do processo na remoção da matéria orgânica e seu efeito na produção de biogás. A adição de 4% de glicerina resultou na maior produção de biogás, cerca de 9307 mL. A eficiência na remoção de DQO diminuiu nos tratamentos com adição de glicerina, sendo a maior redução no tratamento controle, de 68%. Nos demais tratamentos houve um aumento de 90% e 118% para os tratamentos Gli4% e Gli6% respectivamente. As reduções de SV para os tratamentos Gli0%, Gli2%, Gli4% e Gli6%, foram de 18,17%, 61,60%, 24,36% e de 44,83%, para os respectivos tratamentos.

O objetivo desse trabalho foi o de avaliar o desempenho de um reator anaeróbio híbrido de alta taxa (AHHR), contendo biomassa imobilizada em leito ordenado, alimentado com a fração líquida de esterco bovino, na produção de biogás. No estudo, foi utilizado um reator anaeróbio de fluxo ascendente de 12,4 L de volume total (9,2 L de volume útil) com leito ordenado composto por hastes de espuma de poliuretano (PU). O leito ordenado utilizado possuía 32 hastes de espuma de 1,25 cm2 de seção com 50,0 cm de comprimento, posicionadas verticalmente no interior do reator. A alimentação do reator e a recirculação foram realizadas por meio de bombas dosadoras de diafragma. O reator operou na faixa mesofílica de temperatura (de 20 a 40 &#176C) sem a utilização de mecanismos de controle de temperatura. Foram testadas 7 condições operacionais diferentes, variando o tempo de detenção hidráulica (TDH), carga orgânica volumétrica (COV) aplicada e a utilização de recirculação interna. Para cada fase operacional, foram avaliadas a remoção de matéria orgânica e a produção de biogás. O sistema apresentou elevada remoção de matéria orgânica operando com TDH de 3 e 1d, respectivamente, com valores médios de remoção de DQO de 79 &#37 e 71 &#37. O biogás produzido pelo reator apresentou concentração de metano de 57,6 ± 0,5 &#37 e não foi detectada a presença de sulfeto. A maior produção média de metano foi de 1,676 L CH4/d, obtida com COV de 20 kg DQO/m3.d e TDH de 1d, enquanto a maior produção relativa de metano foi de 0,023 L CH4./ g SV.d, obtida com COV de 5 kg DQO/m3.d e TDH de 1d e recirculação. A relação entre alcalinidade intermediária e parcial teve valor médio de 0,32, oscilando na maior parte do tempo entre 0,27 e 0,33, indicando a estabilidade do processo de digestão anaeróbia. Os resultados obtidos indicaram o potencial satisfatório do AHHR para a remoção de matéria orgânica e produção de biogás a partir da fração líquida do esterco bovino nas condições operacionais testadas na pesquisa. / This study aimed at evaluating the biogas production for electricity generation performance of an anaerobic high-rate hybrid reactor (AHHR), containing immobilized biomass in structured-bed, fed with the liquid fraction of cattle manure. In this study, it was used an upflow 12,4 L anaerobic reactor (9,2 L working volume) with structuredbed composed by 32 PU foam stripes (1,25 cm2 cross section and 500 mm length) vertically fixed inside the reactor. The reactor feeding and internal recirculation was made by diaphragm metering pumps. The reactor operated at mesophilic temperature (20 - 40 &#176C) without temperature control system. Different operating conditions were tested (7 stages), changing hydraulic retention time (HRT), organic loading rate (OLR) and recirculation use. COD removal and biogas production were evaluated for each operational condition. The system resulted in high COD removal operating with HRT of 3 and 1d, respectively, with average COD removal of 79 &#37 and 71 &#37. Produced biogas had 57,6 ± 0,5 &#37 of methane and no sulfide. The highest average volumetric methane production was 1,676 L CH4, obtained with OLR of 20 kg COD/m3.d and 1d HRT, and the highest methane yield was 0,023 L CH4/ g VS obtained with OLR of 5 kg COD/m3.d, 1d HRT and recirculation. The intermediate and partial alkalinity relation had an average value of 0,32, varying most of the time between 0,27 and 0,33, indicating the anaerobic digestion process stability. The results indicated the decent COD removal and biogas production using the AHHR fed with the liquid fraction of cattle manure at the operation conditions used in this study.

Le secteur de la méthanisation à la ferme ou territoriale connait un fort développement, entrainant la production de grandes quantités de digestats. Si la fraction solide de ces digestats est généralement utilisée en tant qu’amendement organique, la fraction liquide peut être valorisée par la récupération des éléments minéraux bien que la présence de composés organiques pose des problèmes de traitement et d’élimination. Les objectifs de cette thèse sont i) de caractériser la fraction liquide des digestats et donner des premiers éléments pour leur futur traitement et ii) d’expliquer la variabilité des composés résiduels présents dans cette fraction liquide en relation avec l’origine des substrats, les paramètres du procédé de méthanisation et le type de séparation solide/liquide. Dans une première partie, nous avons caractérisé de manière détaillée onze digestats issus d’installations industrielles de co-digestion. Le fractionnement par neuf filtrations successives de la fraction liquide des digestats a permis de quantifier la contribution des matières en suspension, des colloïdes grossiers et fins et des matières dissoutes aux différents paramètres physico-chimiques et biologiques. Il a été montré la faible biodégradabilité aérobie des composés organiques dont la majeure partie se trouve dans la matière en suspension (> 1,2 µm). Pour élargir la base de données, nous avons caractérisé dix-huit digestats supplémentaires et un digestat de boues de station d’épuration dont les fractions liquides ont été fractionnées par deux filtrations successives (1,2 μm et 1 kDa). L’analyse en composantes principales, la classification hiérarchique et la matrice de corrélation réalisées sur l’ensemble des 30 digestats ont mis en avant l’impact majeur des techniques de séparation solide/liquide sur la composition de la fraction liquide des digestats. Dans le groupe des techniques de séparation hautement performantes, des sous-groupes ont permis de distinguer les digestats à base de boues d’épuration, ceux à base de lisiers porcins et ceux issus de procédés piston thermophiles. Dans le groupe des procédés de séparation à faible performance, les teneurs en DCO et matières sèches de la fraction liquide des digestats ont été corrélées aux teneurs en cultures énergétiques et fumiers bovins dans l’alimentation. Finalement, pour l’ensemble des digestats, le paramètre SUVA, lié à la teneur en matière aromatique et à la stabilisation des composés, a été corrélé au temps de séjour des digesteurs. Pour comprendre l’origine des composés résiduels observés dans la fraction liquide des digestats issus de la co-digestion avec de fortes proportions de fumier bovin, quatre réacteurs CSTR alimentés avec respectivement de la paille de blé, de la bouse de vache et du fumier ont été conduits pendant 48 semaines. Les performances de méthanisation ont mis en évidence le caractère âgé du fumier qui avait été partiellement dégradé pendant le stockage à la ferme. Ainsi la fraction liquide du digestat du fumier a présenté les plus fortes concentrations en composés organiques qui en outre présentaient une complexité, mesurée par fluorimétrie 3D, plus élevée que les autres substrats. La fraction liquide du digestat issue de la méthanisation de la paille a révélé les plus fortes proportions de DCO dans les fractions colloïdales et dissoutes. La faible biodégradabilité des composés organiques et leur forte proportion dans les matières en suspension suggèrent le développement de procédés physico-chimiques de séparation tels que la coagulation pour le traitement de la fraction liquide des digestats. / Agricultural and centralized biogas plants are facing a fast development, leading to the production of huge amounts of digestates. Whereas the solid fraction of digestates is used as fertilizer, the liquid fraction can be valorized by the recovery of mineral materials, although the presence of organic compounds may be problematic for the treatment and disposal of this effluent. The objectives of this thesis are: i) to characterize the liquid fraction of digestates and to provide guidelines for its further treatment, ii) to explain the variability of residual compounds in the liquid fraction of digestates in relation with substrate origin, process parameters and the type of solid-liquid separation. In a first part, eleven digestates from full scale codigestion plants were thoroughly characterized. Their liquid fractions were fractionated by nine successive filtrations, which allowed quantifying the contribution of suspended particles, coarse and fine colloids and dissolved matter on several physico-chemical and biological parameters. Organic compounds were mainly found in suspended particles (> 1.2 µm) and presented low aerobic biodegradability. To enlarge the data base, eighteen more digestates from codigestion and one digestate from waste activated sludge were characterized; their liquid fractions were fractionated by two successive filtrations (1.2 μm and 1 kDa). Principal component analysis, hierarchical clustering analysis and correlation matrix carried out on the 30 digestates set, highlighted the major impact of the solid-liquid separation process on the composition of the liquid fraction of digestates. In the high performance separation process group, subgroups allowed separating digestates from sewage sludge, digestates from pig manure and digestates from plug-flow thermophilic processes. In the low performance separation process group, COD and total solids concentration in the liquid fraction of digestates were correlated to the percentage of energy crops and cow manure in the feed. Finally, SUVA parameter which accounts for aromatic compounds content and the stabilization of organic matter, was correlated to the retention time in digester for the whole digestates set. To understand the origin of residual compounds in the liquid fraction of digestates from co-digestion of high proportions of cattle manure, four CSTR reactors fed with wheat straw, cow dung and cow manure were operated for 48 weeks. Anaerobic digestion performances showed that cow manure had undergone some aerobic degradation during its storage at the farm. Therefore, the liquid fraction of manure digestate had the highest concentrations in organic compounds. In addition, these organic compounds had the highest complexity measured by 3D fluorimetry. The low biodegradability of organic compounds and their high percentage in suspended particles suggest the development of physico-chemical separation process such as coagulation for the treatment of the liquid fraction of digestates

Manure from animal farms and sewage sludge contain pathogens and opportunistic organisms in various concentrations depending on the health of the herds and human sources. Other than for the presence of pathogens, these waste substances are excellent nutrient sources and constitute a preferred organic fertilizer. However, because of the pathogens, the risks of infection of animals or humans increase with the indiscriminate use of manure, especially liquid manure or sludge, for agriculture. This potential problem can increase with the global connectedness of animal herds fed imported feed grown on fields fertilized with local manures. This paper describes a simple, easy-to-use, low-tech hygienization method which conserves nutrients and does not require large investments in infrastructure. The proposed method uses the microbiotic shift during mesophilic fermentation of cow manure or sewage sludge during which gram-negative bacteria, enterococci and yeasts were inactivated below the detection limit of 3 log10 cfu/g while lactobacilli increased up to a thousand fold. Pathogens like Salmonella, Listeria monocytogenes, Staphylococcus aureus, E. coli EHEC O:157 and vegetative Clostridium perfringens were inactivated within 3 days of fermentation. In addition, ECBO-viruses and eggs of Ascaris suum were inactivated within 7 and 56 days, respectively. Compared to the mass lost through composting (15–57%), the loss of mass during fermentation (< 2.45%) is very low and provides strong economic and ecological benefits for this process. This method might be an acceptable hygienization method for developed as well as undeveloped countries, and could play a key role in public and animal health while safely closing the nutrient cycle by reducing the necessity of using energy-inefficient inorganic fertilizer for crop production.

Anaerobic digestion (AD) is becoming a widely adopted technology for conversion of organic waste and nutrient-rich fertiliser production due to its cost-effectiveness and sustainability. In this study, a batch experiment was conducted using five different types of food waste and cow dung (CD). No significant difference was observed among the four substrates that produced the highest methane (P<0.05). Based on the batch experiment results, two substrates were selected for semi-continuous digestion and the highest methane yield (67%) was obtained from co-digestion (CO). PCR-DGGE results revealed higher bacterial and archaeal diversity indices in CO as compared to mono-digestion of CD and mixed food waste. The high-throughput sequence analyses revealed that the Operational Taxonomic Units (OTUs) belonging to the phyla Bacteroidetes, followed by Firmicutes, Actinobacteria and Proteobacteria, were dominant in all treatments. The enhanced methane production in CO could be attributed to the neutral pH and partial shift of archaea from Methanosaeta to Methanosarcina. The digestate and fresh CD were screened for plant growth promoting bacteria (PGPB), nutrient and heavy metal content. The dung contained higher concentrations of heavy metals (P<0.05) and potential pathogens in comparison to the digestate. The use of digestate may, therefore, enhance soil fertility with minimal negative environmental effects. / School of Agriculture and Life Sciences / M. Sc. (Life Sciences)

Im Laborversuch konnte der positive Einfluss einer thermobarischen Vorbehandlung auf die Hydrolysier- und Vergärbarkeit von Rinderfestmist und Rindergülle nachgewiesen werden. Die Laborergebnisse wurden innerhalb eines theoretischen Modells in den Praxismaßstab übertragen, um den Einfluss auf Treibhausgasemissionen, Energiebilanz und Ökonomie zu bewerten. Die Vorbehandlungstemperaturen im Labor lagen zwischen 140 und 220°C in Schritten von 20 K und einer Vorbehandlungszeit von jeweils 5 Minuten. Die höchste Methanmehr¬ausbeute von 58 % konnte bei einer Temperatur von 180°C ermittelt werden. Das Auftreten von Inhibitoren und nicht vergärbaren Bestandteilen führte bei einer Aufbereitungstemperatur von 220°C zu Methanausbeuten, die geringer waren als die des unaufbereiteten Einsatzstoffes. In einer erweiterten Analyse konnte ein funktioneller Zusammenhang zwischen der Methanausbeute nach 30 Tagen und der Methanbildungsrate und -ausbeute während der Beschleunigungsphase gezeigt werden. Mittels einer Regressionsanalyse der so ermittelten Werte wurde nachgewiesen, dass die optimale Aufbereitungstemperatur 164°C ist und die minimale größer als 115°C zu sein hat. Treibhausgasemissionen und Energiebilanz wurden im Rahmen einer Ökobilanz nach ISO 14044 (2006) ermittelt, sowie eine Kosten-Nutzen-Analyse durchgeführt. Dazu wurde eine Anlage zur thermobarischen Vorbehandlung entwickelt und innerhalb eines Modells in eine Biogasanlage integriert. Weiterhin wurde in diesem Modell Maissilage durch Rinderfestmist und / oder Rindergülle als Einsatzstoff ersetzt. Rinderfestmist, ein Einsatzstoff mit hohem organischen Trockenmassegehalt, der ohne Vorbehandlung nicht einsetzbar wäre, erreichte eine energetische Amortisationszeit von 9 Monaten, eine Vermeidung in Höhe der während der Herstellung emittierten Treibhausgase innerhalb von 3 Monaten und eine ökonomische Amortisationszeit von 3 Jahren 3 Monaten, wohingegen Rindergülle keine positiven Effekte zeigte. / Hydrolysis and digestibility of cattle waste as feedstock for anaerobic digestion were improved by thermobarical treatment in lab-scale experiments. The effects of this improvement on greenhouse gas emissions, energy balance and economic benefit was assessed in a full-scale model application. Thermobarical treatment temperatures in lab-scale experiments were 140 to 220°C in 20 K steps for a 5-minute duration. Methane yields could be increased by up to 58 % at a treatment temperature of 180°C. At 220°C, the abundance of inhibitors and other non-digestible substances led to lower methane yields than those obtained from untreated material. In an extended analysis, it could be demonstrated that there is a functional correlation between the methane yields after 30 days and the formation rate and methane yield in the acceleration phase. It could be proved in a regression of these correlation values that the optimum treatment temperature is 164°C and that the minimum treatment temperature should be above 115°C. The theoretical application of a full-scale model was used for assessing energy balance and greenhouse gas emissions following an LCA approach according to ISO 14044 (2006) as well as economy. A model device for thermobarical treatment has been suggested for and theoretically integrated in a biogas plant. The assessment considered the replacement of maize silage as feedstock with liquid and / or solid cattle waste. The integration of thermobarical pretreatment is beneficial for raw material with high organic dry matter content that needs pretreatment to be suitable for anaerobic digestion: Solid cattle waste revealed very short payback times, e.g. 9 months for energy, 3 months for greenhouse gases, and 3 years 3 months for economic amortization, whereas, in contrast, liquid cattle waste did not perform positive replacement effects in this analysis.