Digestión anaerobia de lodos y residuos agroindustriales = Anaerobic digestion of sewage sludge and agro-industrial wastes

158 p.Este trabajo está enfocado al estudio de la digestión anaerobia de lodos de depuradora (primario y secundario) y de residuos agroindustriales (grasas y residuos de biorefinería). Mediante la co-digestión y la utilización de pre-tratamientos se pretende conseguir aumentar el rendimiento del sistema con el consecuente incremento en la producción de metano

La transformación de los residuos, una clave para la producción de energía

[ES] La transformación de los residuos orgánicos en biogás a partir de digestión anaerobia supone un impulso al desarrollo de la economía circular de los países, sobre todo en los sectores de tratamiento de aguas, residuos municipales, industria agropecuaria, del procesado de alimentos, entre muchas otras. El aprovechamiento de residuos orgánicos permite una valorización de algo que ya no tiene utilidad y presenta numerosas ventajas, principalmente la obtención de energía de origen renovable en forma de un gas combustible evitando emisiones de metano y dióxido de carbono asociadas a los combustibles fósiles, pero además el producto sólido resultante puede usarse como biofertilizante, lo que lleva a una gestión más sostenible de este tipo de residuos

Hydrothermal carbonization of olive tree pruning as a sustainableway for improving biomass energy potential: effect of reaction parameters on fuel properties

Hydrothermal carbonization (HTC) allows the conversion of organic waste into a solid product called hydrochar with improved fuel properties. Olive tree pruning biomass (OTP), a very abundant residue in Mediterranean countries, was treated by HTC to obtain a solid fuel similar to coal that could be used in co-combustion processes. Three different reaction temperatures (220, 250, and 280 °C) and reaction times (3, 6, and 9 h) were selected. The hydrochars obtained were extensively analyzed to study their behavior as fuel (i.e., ultimate, proximate, fiber and thermogravimetric analysis, Fourier-transform infrared spectroscopy (FTIR), activation energy, and combustion performance). The concentrations of cellulose, hemicellulose, and lignin in the samples depict a clear and consistent trend with the chemical reactions carried out in this treatment. Regarding O/C and H/C ratios and HHV, the hydrochars generated at more severe conditions are similar to lignite coal, reaching values of HHV up to 29.6 MJ kg-1. The higher stability of the solid is reflected by the increase of the activation energy (≈60 kJ mol-1), and ignition temperatures close to 400 °C. With this, HTC is a proper thermal treatment for the management of raw OTP biomass and its further conversion into a solid biofuel.Judith González-Arias would like to thank the Junta de Castilla y León (Consejería de Educación) fellowship, Orden EDU/1100/2017, cofinanced by the European Social Fund.info:eu-repo/semantics/publishedVersio

Biological treatments of cheese whey for biogas and hydrogen production. Review

A industria leitera caracteriza-se por uma elevada geração de soro de leite, um subproduto do processo de fabricação do queijo, com um elevado conteúdo em materia orgánica na forma de lactose, proteínas e outros compostos a partir da leite. Por esta razão, considera-se um material suscetível de ser valorizado mediante a recuperação destes produtos para posteriores aplicações alimentárias, farmacéuticas a para a obtenção de biocombustíveis. Uma das alternativas para proveitar a energía é a aplicação de tratamentos anaeróbios, sendo uma das tecnologias mais usadas com os residuos sólidos, líquidos , e também as águas residuais. O lacstosuero é considerado um substrato com um elevado potencial para a geração de biogás, é por isso que têm sido aplicado em diferentes estudos. No entanto, apresenta difculdades devido à sua tendência para a acidifcação e a limitação de nutrientes que poden causar falhas durante o processo. Por esta razão, temos promovido outras alternativas, tais como os processos de co-digestão com outros materiais ou a fermentação escura orientada para a produção de hidrogénio. Este artigo centra-se numa revisão blibliográfca dos principáis trabalhos que têm sido desenvolvidos aplicando os processos acima descritos, com uma apresentação dos resultados mais relevantes obtidos considerando a infuência das condições de operação e os fatores que afetam à produção.Dairy industry is characterized by high generation of cheese whey, a byproduct from cheese factories with a high organic matter content in the form of lactose, proteins and other compounds coming from processed milk. If it is not properly disposed it might favour serious environmental pollution problems. However, it is possible the application of recovery technologies in order to obtain its main compounds for further applications such as food or pharmaceutical industry, and for obtaining biofuels. Nowadays, biofuels are an important source of renewable energy as potential future alternative for fossil fuels. For this reason, energetic valorisation of cheese whey has become an interensting alternative. Anaerobic digestion is considered one of the most used technologies in wastewater and solid waste treatments. Several studies have been conducted with cheese whey as a suitable substrate with a considerable biogas potential production. However, it presents some disadvantages due to the rapid acidifcation tendency and nutrient content limitations that might favor failures in the process. For this reason, alternatives like anaerobic co-digestion with other substrates or dark fermentation for hydrogen production have been proposed. This paper intends to review the main works developed applying the mentioned technologies along with its most relevant results considering operation conditions infuence and the environmental factors affecting production.La industria láctea se caracteriza por generar lactosuero como subproducto del proceso de elaboración del queso. El lactosuero presenta un elevado contenido en materia orgánica en forma de lactosa, proteínas y otros compuestos procedentes de la leche. Su vertido incontrolado puede ocasionar problemas de contaminación con un grave impacto ambiental. Sin embargo, la recuperación de algunos componentes del lactosuero permite valorizar este subproducto, encontrando aplicación en la industria alimentaria, farmacéutica y recientemente en la conversión del lactosuero para la producción de biocombustibles. Actualmente, los biocombustibles son una fuente potencial de energía renovable con un papel importante como posibles sustitutos de los combustibles fósiles. Por este motivo, la opción de gestionar el lactosuero mediante una valorización energética ha adquirido gran interés durante los últimos años. Entre las alternativas disponibles de aprovechamiento energético, se encuentra la digestión anaerobia, la cual es una de las tecnologías más empleadas para el tratamiento de diverso tipo de residuos. En el caso del lactosuero, se han desarrollado múltiples trabajos en los que se han utilizado diferentes configuraciones y condiciones de operación con el objetivo de mejorar el funcionamiento del proceso. Gracias a estos trabajos se han podido identificar algunos de los factores que limitan su aplicación como son: la tendencia a la acidificación o la limitación de nutrientes. Por este motivo se han promovido otras alternativas como son los procesos de co-digestión con varios materiales o la fermentación oscura. El objetivo de este artículo es la realización de una revisión bibliográfica de los principales trabajos realizados en los que se contemplan los procesos biológicos anteriormente mencionados. Se presentan los resultados más relevantes, así como la influencia de las condiciones de operación y los factores que afectan a la producción de biogás

Biological treatments of cheese whey for biogas and hydrogen production. Review

A industria leitera caracteriza-se por uma elevada geração de soro de leite, um subproduto do processo de fabricação do queijo, com um elevado conteúdo em materia orgánica na forma de lactose, proteínas e outros compostos a partir da leite. Por esta razão, considera-se um material suscetível de ser valorizado mediante a recuperação destes produtos para posteriores aplicações alimentárias, farmacéuticas a para a obtenção de biocombustíveis. Uma das alternativas para proveitar a energía é a aplicação de tratamentos anaeróbios, sendo uma das tecnologias mais usadas com os residuos sólidos, líquidos , e também as águas residuais. O lacstosuero é considerado um substrato com um elevado potencial para a geração de biogás, é por isso que têm sido aplicado em diferentes estudos. No entanto, apresenta difculdades devido à sua tendência para a acidifcação e a limitação de nutrientes que poden causar falhas durante o processo. Por esta razão, temos promovido outras alternativas, tais como os processos de co-digestão com outros materiais ou a fermentação escura orientada para a produção de hidrogénio. Este artigo centra-se numa revisão blibliográfca dos principáis trabalhos que têm sido desenvolvidos aplicando os processos acima descritos, com uma apresentação dos resultados mais relevantes obtidos considerando a infuência das condições de operação e os fatores que afetam à produção.Dairy industry is characterized by high generation of cheese whey, a byproduct from cheese factories with a high organic matter content in the form of lactose, proteins and other compounds coming from processed milk. If it is not properly disposed it might favour serious environmental pollution problems. However, it is possible the application of recovery technologies in order to obtain its main compounds for further applications such as food or pharmaceutical industry, and for obtaining biofuels. Nowadays, biofuels are an important source of renewable energy as potential future alternative for fossil fuels. For this reason, energetic valorisation of cheese whey has become an interensting alternative. Anaerobic digestion is considered one of the most used technologies in wastewater and solid waste treatments. Several studies have been conducted with cheese whey as a suitable substrate with a considerable biogas potential production. However, it presents some disadvantages due to the rapid acidifcation tendency and nutrient content limitations that might favor failures in the process. For this reason, alternatives like anaerobic co-digestion with other substrates or dark fermentation for hydrogen production have been proposed. This paper intends to review the main works developed applying the mentioned technologies along with its most relevant results considering operation conditions infuence and the environmental factors affecting production.La industria láctea se caracteriza por generar lactosuero como subproducto del proceso de elaboración del queso. El lactosuero presenta un elevado contenido en materia orgánica en forma de lactosa, proteínas y otros compuestos procedentes de la leche. Su vertido incontrolado puede ocasionar problemas de contaminación con un grave impacto ambiental. Sin embargo, la recuperación de algunos componentes del lactosuero permite valorizar este subproducto, encontrando aplicación en la industria alimentaria, farmacéutica y recientemente en la conversión del lactosuero para la producción de biocombustibles. Actualmente, los biocombustibles son una fuente potencial de energía renovable con un papel importante como posibles sustitutos de los combustibles fósiles. Por este motivo, la opción de gestionar el lactosuero mediante una valorización energética ha adquirido gran interés durante los últimos años. Entre las alternativas disponibles de aprovechamiento energético, se encuentra la digestión anaerobia, la cual es una de las tecnologías más empleadas para el tratamiento de diverso tipo de residuos. En el caso del lactosuero, se han desarrollado múltiples trabajos en los que se han utilizado diferentes configuraciones y condiciones de operación con el objetivo de mejorar el funcionamiento del proceso. Gracias a estos trabajos se han podido identificar algunos de los factores que limitan su aplicación como son: la tendencia a la acidificación o la limitación de nutrientes. Por este motivo se han promovido otras alternativas como son los procesos de co-digestión con varios materiales o la fermentación oscura. El objetivo de este artículo es la realización de una revisión bibliográfica de los principales trabajos realizados en los que se contemplan los procesos biológicos anteriormente mencionados. Se presentan los resultados más relevantes, así como la influencia de las condiciones de operación y los factores que afectan a la producción de biogás

El Problem Based Learning plus, PBL+, a examen, una metodología ecléctica y flexible, para competencias prácticas en ingeniería

[ES] Problem Based Learning Plus (PBL+) es una metodología docente para alcanzar las competencias prácticas en ingeniería, incluyendo a ingenieros químicos, ambientales y agrónomos, y también a biotecnólogos especializados en procesos de producción. PBL+ se basa en la metodología PBL tradicional, pero combina otras metodologías de enseñanza-aprendizaje: la clase invertida, el uso de rúbricas para la evaluación de la actividad, el aprendizaje colaborativo y en algunos casos, el aprendizaje-servicio. Un aspecto relevante es que los estudiantes son libres de elegir el problema sobre el que van a trabajar. Aún más importante es que el problema a resolver debe ser una situación real a la que se enfrenta la empresa. Son los estudiantes los que entran en contacto con una empresa cuyo campo de actividad corresponda a las competencias de la asignatura y seleccionan, junto con un representante de la empresa, el problema a resolver. De este modo, los estudiantes tienen un papel activo en la definición de las prácticas de la asignatura. Esta forma flexible de construir el currículo del estudiante ha demostrado motivarlos, siendo una excelente estrategia para abordar problemas reales de su especialidad. No obstante, no todos los sectores de la ingeniería están dispuestos a compartir sus problemas con los estudiantes. En este sentido, la industria biotecnológica es muy reticente a hacerlo, mientras que el sector agrario es proclive a ello. En este trabajo, se resumen los resultados de la evaluación a la que se ha sometido el PBL+ durante 4 cursos consecutivos, aplicando 9 indicadores que evalúan 7 resultados de aprendizaje. Además, se resume el tipo de problemas sobre los que han trabajado los estudiantes de ingeniería agronómica durante los 4 cursos, que corresponden a los problemas que más preocupan a las empresas del sector: el 60% de los problemas están relacionados con aspectos fitosanitarios, principalmente plagas o enfermedades emergentes. En segundo lugar, el 30% corresponde a alteraciones en el crecimiento de los cultivos por factores abióticos. El 10% restante consiste en adaptar los procesos productivos a los cambios legislativo

Valorization of Fourth-Range Wastes: Evaluating Pyrolytic Behavior of Fresh and Digested Wastes

Changes in daily habits and a stressful lifestyle create modifications in consumer preferences and open opportunities to new market products. This is the case of fourth-range products in which the industrial sector generates a waste stream of high quality. Valorization of this type of waste as a single stream is desirable to avoid lowering quality with other low-grade materials. Anaerobic digestion of fourth-range wastes was studied under discontinuous and semi-continuous conditions. A high carbon content characterizes the organic material composed of fruit and vegetable wastes. The fast degradation of the substrate indicated no limitations associated with the hydrolysis stage, as observed from kinetic parameters estimated from batch assays. However, the easiness of degradation did not translate into short hydraulic retention times when operating under semi-continuous conditions. Additionally, the insufficient amount of nutrients prevented the development of a well-balanced digestion process. Specific methane production was 325 mL CH4/g VS added at a hydraulic retention time of 30 days. However, solid accumulation was observed at the end of the experiment, indicating that conditions established did not allow for the complete conversion of the organic material. Digestate evaluation using thermal analysis under inert conditions showed a thermal profile evidencing the presence of complex components and a high tendency to char formation

New Biofuel Alternatives: Integrating Waste Management and Single Cell Oil Production

Concerns about greenhouse gas emissions have increased research efforts into alternatives in bio-based processes. With regard to transport fuel, bioethanol and biodiesel are still the main biofuels used. It is expected that future production of these biofuels will be based on processes using either non-food competing biomasses, or characterised by low CO2 emissions. Many microorganisms, such as microalgae, yeast, bacteria and fungi, have the ability to accumulate oils under special culture conditions. Microbial oils might become one of the potential feed-stocks for biodiesel production in the near future. The use of these oils is currently under extensive research in order to reduce production costs associated with the fermentation process, which is a crucial factor to increase economic feasibility. An important way to reduce processing costs is the use of wastes as carbon sources. The aim of the present review is to describe the main aspects related to the use of different oleaginous microorganisms for lipid production and their performance when using bio-wastes. The possibilities for combining hydrogen (H2) and lipid production are also explored in an attempt for improving the economic feasibility of the process

Effect of Ultrasound Pretreatment on Sludge Digestion and Dewatering Characteristics: Application of Particle Size Analysis

The aim of this work was to study the effect of ultrasonic pretreatment on sludge digestion, particle size distribution (PSD), and dewaterability of digestates (measured by capillary suction time (CST) and specific resistance to filtration (SRF)). Sludge was pretreated with ultrasound (24 kHz) at an energy dosage of 4300 kJ/kg TS. Digestibility of sludge was increased by ultrasound pretreatment resulting in a higher specific methane production (SMP). The digestate of pretreated waste activated sludge (WAS) obtained under batch conditions presented a better dewatering performance. Digestion under semi-continuous conditions was evaluated using sewage sludge (mixture of primary sludge and WAS). In this case, digestates presented a much higher mean particle size for both cases evaluated (pretreated and non-pretreated) than that obtained under batch conditions. A wide PSD was a characteristic of these digestate samples. Flow dynamics inside the reactor resulted in the presence of high-diameter flocs, thus significantly affecting the mean particle size and specific surface area (SSA) values

Improving Anaerobic Digestion of Sewage Sludge by Hydrogen Addition: Analysis of Microbial Populations and Process Performance

The effect of hydrogen pulse addition on digestion performance of sewage sludge was evaluated as a means for studying the increase in efficiency of methane production. Microbial communities were also evaluated to get an insight of the changes caused by the operational modifications of the digester. An energy evaluation of this alternative was performed considering the theoretical process of coupling bioelectrochemical systems (BES) for the treatment of wastewater along with hydrogen production and the subsequent anaerobic digestion. The addition of hydrogen to sewage sludge digestion resulted in an increase of 12% in biogas production over the control (1353 mL CH4 d−1 at an injection flow rate of 1938 mL H2 d−1). The liquid phase of the sludge reactor and the H2 supplemented one did not show significant differences, thus indicating that the application of hydrogen as the co-substrate was not detrimental. High-throughput sequencing analysis showed slight changes in archaeal relative abundance after hydrogen addition, whereas eubacterial community structure and composition revealed noteworthy shifts. The mass and energy balance indicated that the amount of hydrogen obtained from a hypothetical BES can be assimilated in the sludge digester, improving biogas production, but this configuration was not capable of covering all energy needs under the proposed scenario