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  • Anaerobic disintegration of agro-industrial organic waste. Reliability of parameters identification

     Rodríguez-Abalde, Ángela; Zivko, Juznic Zonta; Fernández, B.; Flotats Ripoll, Xavier
    World Congress on Anaerobic Digestion
    Presentation's date: 2013-06-27
    Presentation of work at congresses

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  • Characterization of the anaerobic digestion of proteins containing animal by-products, using simultaneous batch experiments

     Flotats Ripoll, Xavier; Fernández, B.; Palatsi Civit, Jordi
    World Congress on Anaerobic Digestion
    Presentation's date: 2013-06-27
    Presentation of work at congresses

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  • Feasibility of enriching anammox bacteria using sludge from two wastewater treatment plants

     Magrí Aloy, Albert; Guivernau, Miriam; Delavari, Azar; Flotats Ripoll, Xavier; Viñas Canals, Marc; Prenafeta Boldú, Francesc Xavier; Vanotti, M.B.
    International UFZ-Deltares Conference on Groundwater-Soil-Systems and Water Resource Management
    Presentation's date: 2013-04-16
    Presentation of work at congresses

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  • Development of a global framework for the mathematical modelling of the composting process

     Illa, Josep; Flotats Ripoll, Xavier
    International Conference of WASTES: solutions, treatments and opportunities
    Presentation's date: 2013-09-12
    Presentation of work at congresses

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    This study presents the structure of a mathematical model of the composting process. It sets up a methodology for the presentation of the biological and physic-chemical phenomena involved, making possible to couple biological models developed by different authors to the proposed physical model. This one considers the substrate as a porous media in which the three phases, solid, liquid and gaseous, are present. Mass and energy flows between them are governed by basic transfer laws. The gaseous phase is considered, in the base model, as a completely stirred mixture of oxygen, CO2, ammonia, water vapour and nitrogen, both considered as ideal gases. Its extension to the 1D space incorporates the movement of the gaseous phase due to pressure gradient, the conductive heat transfer in the solid matrix, the convective energy transport, both as sensible and latent heat, and the convective mass transport of gaseous components. The simulations, run with a unique set of physical, stoichiometric and kinetic parameters, for experiments with different substrates, reproduce satisfactorily the main trends observed.

  • Trends on manure processing in Europe

     Flotats Ripoll, Xavier; Bonmatí Blasi, August; Palatsi Civit, Jordi; Foged, Henning Lyngso
    International Conference of WASTES: solutions, treatments and opportunities
    Presentation's date: 2013-09-12
    Presentation of work at congresses

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    Manure treatment technologies are becoming important tools for the application of regulations concerning water and soil protection, greenhouse gasses emission mitigation, fertilizer resources recovery and renewable energy production. The technological strategy to be applied, as a combination of processes to fulfil a given objectives, depends on many factors, mainly related to local or regional conditions. As a result of the study described, 19,196 treatment units were identified, processing 7.8% of the livestock manure production in the EU, equal to 108 million tonnes/year, containing 556,000 tonnes of nitrogen and 139,000 tonnes of phosphorus. Products obtained from processing were classified in 11 groups, with three types of manure processing products being marketed at considerable volume, namely "separation solids", "manure compost" and "dried manure and pellets". Processing products standards must be developed as a way to support the development of the market infrastructure. Anaerobic digestion was identified as a focal sustainable technology to combine with further processes, because of its contribution to mineralization and better recycling of nutrients, but also due to renewable energy production and greenhouse gases mitigation

  • Effect of high pressure pre-treatment on anaerobic digestion of slaughterhouse waste

     Rodríguez-Abalde, Ángela; Fernández, B.; Flotats Ripoll, Xavier
    World Congress on Anaerobic Digestion
    Presentation's date: 2013-06-27
    Presentation of work at congresses

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  • Characterization of the anaerobic digestion of thermal pre-treated slaughterhouse waste by applying new IR techniques

     Rodríguez-Abalde, Ángela; Gómez, X.; Blanco, D.; Cuetos, María José; Flotats Ripoll, Xavier; Fernández, B.
    World Congress on Anaerobic Digestion
    Presentation's date: 2013-06-27
    Presentation of work at congresses

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  • Saponification pretreatment and solids recirculation as a new anaerobic process for the treatment of slaughterhouse waste

     Affes, Rim; Palatsi Civit, Jordi; Flotats Ripoll, Xavier; Carrère, Helene; Steyer, Jean Phillipe; Battimelli, Audrey
    Bioresource technology
    Date of publication: 2013-03
    Journal article

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  • Procesado de deyecciones ganaderas

     Palatsi Civit, Jordi; Bonmatí Blasi, August; Magrí Aloy, Albert; Foged, Henning; Schelde, Karl Martin; Flotats Ripoll, Xavier
    Ganadería : revista técnica ganadera
    Date of publication: 2013-06
    Journal article

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  • Modelling inhibitory effects of long chain fatty acids in the anaerobic digestion process

     Juznik Zonta, Zivko; Alves, Madalena; Flotats Ripoll, Xavier; Palatsi Civit, Jordi
    Water research (Oxford)
    Date of publication: 2013-03
    Journal article

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  • Study of thermal pre-treatment on anaerobic digestion of slaughterhouse waste by TGA-MS and FTIR spectroscopy

     Rodríguez-Abalde, Ángela; Gómez, Xiomar; Blanco, Daniel; Cuetos, María José; Fernández García, Belén; Flotats Ripoll, Xavier
    Waste management and research
    Date of publication: 2013-12
    Journal article

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    Thermogravimetric analysis coupled to mass spectrometry (TGA-MS) and Fourier-transform infrared spectroscopy (FTIR) were used to describe the effect of pasteurization as a hygienic pre-treatment of animal by-products over biogas production. Piggery and poultry meat wastes were used as substrates for assessing the anaerobic digestion under batch conditions at mesophilic range. Poultry waste was characterized by high protein and carbohydrate content, while piggery waste presented a major fraction of fat and lower carbohydrate content. Results from anaerobic digestion tests showed a lower methane yield for the pre-treated poultry sample. TGAMS and FTIR spectroscopy allowed the qualitative identification of recalcitrant nitrogen-containing compounds in the pre-treated poultry sample, produced by Maillard reactions. In the case of piggery waste, the recalcitrant compounds were not detected and its biodegradability test reported higher methane yield and production rates. TGA-MS and FTIR spectroscopy were demonstrated to be useful tools for explaining results obtained by anaerobic biodegradability test and in describing the presence of inhibitory problems.

  • Anaerobic digestion of animal by-products. Pre-treatments and co-digestion

     Rodríguez Abalde, Ángela
    Defense's date: 2013-11-18
    Department of Agri-Food Engineering and Biotechnology, Universitat Politècnica de Catalunya
    Theses

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  • Study of methods for the improvement of the anaerobic digestion of lipids and long chain fatty acids  Open access

     Affes, Rim
    Defense's date: 2013-05-14
    Department of Agri-Food Engineering and Biotechnology, Universitat Politècnica de Catalunya
    Theses

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    Anaerobic digestion is a biochemical process that transforms diverse categories of biomass feedstock to renewable energy, in the form of methane, and contributes to resources conservation and greenhouse gases emission mitigation. Lipid-rich waste and wastewaters have a high energy potential, however efficient methane recovery with conventional anaerobic digestion technology is not easy to achieve because of a wide assortment of operational problems mainly related to the accumulation of long chain fatty acids (LCFA), products of lipids hydrolysis, in the system. The objective of the present dissertation is to test and to evaluate new methodologies and strategies to improve the anaerobic digestion of high-strength lipid waste. In a preliminary approach, the suitability and the attractiveness of high-strength lipid wastes and slaughterhouse wastes for biogas production was confirmed, suffice to control the applied organic load. The obtained results reinforced the existing knowledge describing the flotation and wash-out of substrate/biomass and the inhibition phenomena affecting the microbial population, as the main process drawbacks. The results of studies submitting anaerobic reactors to increasing concentrations of lipids/LCFA underlined the importance of the adsorption of LCFA onto the microbial cell membrane as limiting factor, guiding further research to found new technical approaches in order to control the biomass-LCFA adsorption dynamics. The use of inorganic adsorbents to capture LCFA prior to the anaerobic digestion process or the application of sequential low-energy ultrasonic pulses in order to control the adsorption-desorption kinetics were tested with interesting results. However, the effectiveness of these strategies was limited by the proportion of inorganic adsorbent/LCFA and the cumulative damaging effect of ultrasonic treatment over biomass, respectively. Further studies are thus required to optimize the efficiency and the applicability of these strategies. Efficient conversion of complex high-strength lipid waste to methane was proved to be possible in a novel reactor system configuration combining saponification pre-treatment and digested solids recirculation to the anaerobic digestion process, to increase solids retention time. A start-up step consisting on pulse-feeding cycles of the fatty waste prior to the semi-continuous process promoted an adapted microbial community for LCFA mineralization. The feasibility of this system configuration for solid slaughterhouse fatty waste was evidenced at lab scale reactors, reaching organic matter removal efficiencies higher than 90%. The comparison of this configuration with systems without saponification or without digested solids recirculation confirmed the synergistic effect of both strategies. The use of high throughput sequencing approach (454-pyrosequencing) to characterize the evolution of the biodiversity and the phylogenetic structure of the microbial community during the operation of the tested configurations concluded that a selection of a defined functional acidogenic population (ß-oxidizers) was induced by substrate pretreatment. Contrary, the solids recirculation resulted in an enrichment of the methanogenic biodiversity, mainly of hydrogenotrophic archaea. Based on the satisfactory results obtained with the strategies studied in the present dissertation, it is expected that lipid-rich waste valorization will be a real alternative to increase renewable energy production through anaerobic digestion process.

  • Top reviewer de Waste Management

     Flotats Ripoll, Xavier
    Award or recognition

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    Pròleg  Open access

     Flotats Ripoll, Xavier
    Date of publication: 2012
    Book chapter

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  • Saponification and biomass recirculation integration as a new anaerobic system concept for the treatment of solid fatty wastes

     Affes, Rim; Palatsi Civit, Jordi; Flotats Ripoll, Xavier; Carrère, Helene; Steyer, Jean Phillipe; Battimelli, Audrey
    International Conference on Engineering for Waste and Biomass Valorisation
    Presentation's date: 2012-09-11
    Presentation of work at congresses

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  • Multi-criteria analyses of wastewater treatment bio-processes under an uncertainty and a multiplicity of steady states

     Juznik Zonta, Zivko; Kocijan, Jus; Flotats Ripoll, Xavier; Vrecko, Darko
    Water research (Oxford)
    Date of publication: 2012-11-15
    Journal article

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  • Modeling Biotechnological Processes under Uncertainty. Anaerobic Digestion as Case Study  Open access

     Juznic Zonta, Zivko
    Defense's date: 2012-10-26
    Department of Engineering Design, Universitat Politècnica de Catalunya
    Theses

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    En la pràctica de l’enginyeria, quan un model explícit d’un procés està disponible, es poden realitzar experiments numèrics per tal de predir el comportament futur del sistema, explicar o descriure el seu estat ocult, guiar la recopilació de dades,... Generalment, les dinàmiques del sistema són complexes i difícils d’observar amb precisió. Qualsevol aproximació de la realitat observada per mitjà d’un modelatge implica necessàriament incertesa. Per fomentar la confiança en els resultats del model, aquesta incertesa ha de ser caracteritzada i quantificada de forma explícita. En aquest projecte de tesi, particular atenció es proporciona a la incertesa associada als paràmetres del model i les seves implicacions per a l’optimització de bio-processos. Com a cas d’estudi, es considera per a la modelització la digestió anaeròbia. La producció controlada de biogàs per digestió anaeròbica s'ha trobat una activitat rendible, a més de ser una font d'energia renovable. No obstant això, els marges de millora per a aquesta tecnologia són amplis. La co-digestió anaeròbia amb dos o més materials d’entrada és una manera de fer que la biomassa de baixa producció de biogàs sigui aplicable a escala industrial. Entre els possibles co-substrats, els residus orgànics rics en lípids resulten atractius pel seu alt potencial energètic. El principal factor limitant per a aquesta estratègia és la inhibició de la digestió anaeròbica pels àcids grassos de cadena llarga. La modelització matemàtica ofereix una aproximació útil de la complexa i delicada activitat microbiologia d’aquest sistema de digestió anaeròbica. L’objectiu subjacent del projecte de tesi és millorar el procés de tractament d'aigües residuals amb l’ajuda de la modelització i l’anàlisi d’incertesa. D’acord amb aquest objectiu, es desenvolupa un entorn de simulació anomenat “planta virtual” (VP) amb la fi de aplicar-lo al modelatge de la co-digestió anaeròbia i fangs activats. A l’entorn de la VP, es proposa i testeja noves dinàmiques fonamentals del procés d’inhibició pels àcids grassos de cadena llarga i es compara diferents procediments d’inferència per l’estimació del la incertesa dels paràmetres. D’altra banda, es proposa una anàlisi de criteris múltiples en condicions d’incertesa. El mètode s’aplica a una planta industrial de co-digestió anaeròbica. Com a conclusió, l’eina de la "planta virtual" es va trobar fiable i fàcil d’usar en el modelat dels processos de tractament biològics com fangs activats i digestió anaeròbia. El model d’inhibició per àcids grassos a cadena llarga ha estat capaç de reproduir i interpretar les dades experimentals obtingudes en prèvies investigacions. No obstant això, l’estimació de la incertesa dels paràmetres i la falsificació del model d’inhibició són tasques d’investigació futura. El procediment d’inferència Bayesiana s’ha demostrat útil per enfrontar-se amb èxit al problema de l’estimació de la incertesa dels paràmetres relatius a models de la digestió anaeròbia i dels fangs activats. La anàlisi de criteris múltiples sota incertesa ha permès una considerable millora en l’eficiència i de la fiabilitat d’operació d’una planta industrial de biogàs. No obstant això, com a treball futur es fa necessari millorar el procediment d’obtenció de les entrades a l’anàlisi de criteris múltiples i disminuir la càrrega computacional requerida per aquesta anàlisi.

    In engineering practice, when an explicit model of a system is available, numerical experiments can be performed in order to predict the future behavior of the system, explain or describe its hidden state, guide data collection, etc. Typically, the dynamics of the system are complex and difficult to observe with precision. Any approximation of the observed reality within an explicit model necessary implies uncertainty, which should be characterized and quantified to build confidence over model results. Uncertainty associated with model-parameter and its implications for bio-process optimization are of main concern in this PhD work. As a bio-process case study, the anaerobic digestion is considered for modeling. The production of biogas by controlled anaerobic digestion could be a profitable activity, apart of being a renewable energy source. However, the margins to improve this technology are wide. Anaerobic co-digestion with two or more input materials is a way to make low biogas yield biomass applicable at industrial scale. Among the possible co-substrates, lipids-rich wastes are attractive for their high energetic potential. The main limiting factor for this strategy is the inhibition of anaerobic digestion by long chain fatty acids. Modeling provides a useful approximation of the complex and delicate microbiology activity of this anaerobic digestion system. The underlying goal of the PhD project is to improve biotechnological processes with the aid of modeling and uncertainty analysis. With this goal in mind, a general purpose, user-friendly, simulation environment called “virtual plant” (VP) was build and applied to anaerobic co-digestion and activated sludge modeling. Within the VP tool, new core dynamics of the long chain fatty acids (LCFA) inhibition process were proposed and tested and different inferential procedures for the estimation of parameter-uncertainty were compared. Finally, a proposed multi-criteria analysis under uncertainty and multiplicity was applied to an industrial anaerobic co-digestion biogas plant. In conclusion, the developed VP toolkit was found reliable and user-friendly when modeling activated sludge and anaerobic digestion systems. The proposed LCFA-inhibition model was able to reproduce correctly the experimental data at hand and enabled its interpretation. However, uncertainty estimation of parameters and falsification of the proposed model of LCFA-inhibition are still missing. The Bayesian procedure was proved useful when addressing the estimation of parameter uncertainty of anaerobic digestion and activated sludge models. A considerable improvement in the operation efficiency and reliability of an industrial biogas plant was possible within the proposed multi-criteria analysis. However, future work is needed to improve the procedure of elicitation of the inputs for this multi-criteria analysis and decrease its computational burden.

    En la práctica de la ingeniería, cuando un modelo explícito de un proceso está disponible, se pueden realizar experimentos numéricos para predecir el comportamiento futuro del sistema, explicar o describir su estado oculto, guiar la recopilación de datos,. . . Generalmente, las dinámicas del sistema son complejas y difíciles de observar con precisión. Cualquier aproximación de la realidad observada a través de un modelado implica necesariamente incertidumbre. Para fomentar la confianza en los resultados del modelo, esta incertidumbre debe ser caracterizada y cuantificada de forma explícita. En este proyecto de tesis, particular atención se proporciona a la incertidumbre asociada a los parámetros del modelo y sus implicaciones para la optimización de bio-procesos. Como caso de estudio, se considera para la modelización la digestión anaerobia. La producción controlada de biogás por digestión anaeróbica se ha encontrado una actividad rentable, además de ser una fuente de energía renovable. Sin embargo, los márgenes de mejora para esta tecnología son amplios. La co-digestión anaerobia con dos o más materiales de entrada es una manera de hacer que la biomasa de baja producción de biogás sea aplicable a escala industrial. Entre los posibles co-sustratos, los residuos orgánicos ricos en lípidos resultan atractivos por su alto potencial energético. El principal factor limitante para esta estrategia es la inhibición de la digestión anaeróbica por los ácidos grasos de cadena larga. La modelización matemática ofrece una aproximación útil de la compleja y delicada actividad microbiológica de este sistema de digestión anaeróbica. El objetivo subyacente del proyecto de tesis es mejorar los procesos biotecnológicos con la ayuda de la modelización y el análisis de incertidumbre. De acuerdo con este objetivo, se desarrolla un entorno de simulación llamado “planta virtual” (VP) con el fin de aplicarlo al modelado de la co-digestión anaerobia y fangos activados. En el entorno de la VP, se propone y testea nuevas dinámicas fundamentales del proceso de inhibición por ácidos grasos de cadena larga y se compara diferentes procedimientos de inferencia para la estimación del la incertidumbre de los parámetros. Por otra parte, se propone un análisis de criterios múltiples en condiciones de incertidumbre y multiplicidad de equilibrios. El método se aplica a una planta industrial de co-digestión anaeróbica. Como conclusión, la herramienta de la “planta virtual” se encontró fiable y fácil de usar en el modelado de los procesos de tratamiento biológicos como lodos activados y digestión anaerobia. El modelo de inhibición por ácidos grasos a cadena larga ha sido capaz de reproducir y ha permitido de interpretar los datos experimentales obtenidos en previas investigaciones. Sin embargo, la estimación de la incertidumbre de los parámetros y la falsificación del modelo de inhibición son tareas de investigación futura. El procedimiento de inferencia Bayesiana se ha demostrado útil para enfrentarse con éxito al problema de la estimación de la incertidumbre de los parámetros relativos a modelos de la digestión anaerobia y de los lodos activados. La propuesta análisis de criterios múltiples ha permitido una considerable mejora en la eficiencia y de la fiabilidad de operación de una planta industrial de biogás. Sin embargo, como trabajo futuro se rende necesario mejorar el procedimiento de obtención de las entradas al análisis de criterios múltiples y disminuir la carga computacional requerida por tal análisis.

  • Modelització matemàtica de la transferència de massa i energia en el procés de compostatge  Open access

     Illa Alibés, Josep
    Defense's date: 2012-11-23
    Institute for Research on Science and Technology for Sustainability, Universitat Politècnica de Catalunya
    Theses

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    El procés de compostatge és complex degut a que hi intervenen simultàniamentfenòmens de naturalesa molt diversa que interactuen entre ells. La modelitzaciómatemàtica és una eina que facilita l’anàlisi d’aquests sistemes complexos, però elnivell de desenvolupament i aplicació ha estat força limitat fins a l’actualitat. En elpresent treball es desenvolupa un model matemàtic determinista del procés decompostatge basat en les lleis bàsiques dels fenòmens físics i biològics que permetexplicar i quantificar els principals fenòmens observats durant el procés.El model desenvolupat estableix una metodologia de presentació dels fenòmensbiològics que permet acoblar al model físic proposat models desenvolupats per altresautors. Aquest considera el substrat com una matriu porosa constituïda per les tres fases,sòlida, líquida i gasosa, entre les que s’estableixen fluxos de massa i energia governatsper les lleis bàsiques de transferència. La fase gasosa, una mescla d’oxigen, CO2,amoníac, vapor d’aigua i nitrogen, és considerada com de mescla completa en el modelbase. La seva extensió a l’espai 1D incorpora el moviment de la fase gasosa degut agradients de pressió, el transport conductiu d’escalfor al sí de la matriu porosa,l’arrossegament convectiu d’energia, tant en forma de calor sensible com latent, i eltransport dels components de la fase gasosa.S’han dissenyat i construït tres reactors verticals estàtics d’aireig forçat a escala delaboratori i s’han operat amb diferents mescles de residus, a fi d’obtenir informació percontrastar la bondat del model desenvolupat. Durant els experiments s’ha mesurat ienregistrat l’evolució de diferents variables del procés: temperatura a diferents puntsdels reactors, concentracions d’oxigen i CO2 als gasos de sortida, massa total en elsreactors, cabal d’aire insuflat, pressió de l’aire a l’entrada dels reactors, així coml’assentament a diferents nivells del material en compostatge. A principi i final deprocés s’ha mesurat el contingut d’humitat a diferents nivells del material.Les simulacions numèriques, realitzades amb un únic conjunt de paràmetres físics,estequiomètrics i cinètics per als diferents experiments amb substrats diferents,reprodueixen satisfactòriament les tendències observades en les dades experimentals, toti que aquestes mostren que la hipòtesi de simetria radial en els reactors no sempre esverifica. L’anàlisi de sensibilitat realitzada ha permès identificar els paràmetres físicsque més influeixen en l’evolució del procés. Es proposa una equació de 3 paràmetresper quantificar el camp d’assentaments dins el material en compostatge en funció deltemps. A més, s’ha establert una equació que relaciona l’assentament del material ambel consum acumulat d’oxigen.En síntesi, el model desenvolupat simula satisfactòriament les tendències en l’evolucióde les variables de procés observades, integra els diferents fenòmens presents en elprocés de compostatge i permet quantificar la seva importància relativa. L’estructuraoberta del model facilita la incorporació de nous fenòmens.

    El proceso de compostaje es complejo debido a que en él intervienen simultáneamentefenómenos de naturaleza muy distinta interaccionando entre ellos. La modelizaciónmatemática es una herramienta que facilita el análisis de estos sistemas complejos, peroel nivel de desarrollo y aplicación al proceso de compostaje ha sido bastante limitadohasta la actualidad. En el presente trabajo se desarrolla un modelo matemáticodeterminista del proceso de compostaje basado en les leyes básicas de los fenómenosfísicos y biológicos que permite explicar y cuantificar los principales fenómenosobservados durante el proceso.El modelo desarrollado establece una metodología de presentación de los fenómenosbiológicos que permite acoplar al modelo físico propuesto modelos desarrollados porotros autores. Este considera el sustrato como una matriz porosa constituida por las tresfases, sólida, líquida i gaseosa, entre las que se establecen flujos de masa y energíagobernados por las leyes básicas de transferencia. La fase gaseosa, una mezcla deoxígeno, CO2, amoníaco, vapor de agua y nitrógeno, es considerada como de mezclacompleta en el modelo base. Su extensión al espacio 1D incorpora el movimiento de lafase gaseosa debido a gradientes de presión, el transporte conductivo de calor dentro dela matriz porosa, el arrastre convectivo de energía, tanto en forma de calor sensiblecomo latente, y el transporte de los componentes de la fase gaseosa.Se han diseñado y construido tres reactores verticales estáticos de aireación forzada aescala de laboratorio y se han operado con distintas mezclas de residuos, a fin deobtener información para contrastar la bondad del modelo desarrollado. Durante losexperimentos se ha medido y registrado la evolución de diferentes variables del proceso:temperatura a distintos puntos de los reactores, concentraciones de oxígeno y CO2 enlos gases de salida, masa total en los reactores, caudal de aire insuflado, presión del airea la entrada de los reactores, así como el asentamiento a diferentes niveles del materialen compostaje. A principio y final de proceso se ha medido el contenido de humedad adiferentes niveles del material.Las simulaciones numéricas, realizadas con un único conjunto de parámetros físicos,estequiométricos y cinéticos para los diferentes experimentos con sustratos distintos,reproducen satisfactoriamente las tendencias observadas en los datos experimentales, apesar de que éstos muestran que la hipótesis de simetría radial en los reactores nosiempre se verifica. El análisis de sensibilidad realizado ha permitido identificaraquellos parámetros físicos con más influencia en la evolución del proceso. Se proponeuna ecuación de 3 parámetros para cuantificar el campo de asentamiento en el materialen compostaje en función del tiempo. Además, se ha establecido una ecuación querelaciona el asentamiento del material con el consumo acumulado de oxígeno.En síntesis, el modelo desarrollado simula satisfactoriamente las tendencias en laevolución de las variables de proceso observadas, integra los distintos fenómenospresentes en el proceso de compostaje y permite cuantificar su importancia relativa. Laestructura abierta del modelo facilita la incorporación de nuevos fenómenos

    The interaction of phenomena of different nature in the composting process makes it complex. Mathematical modelling is ahelpful tool to analyse such complex systems, but its development and application to the composting process has beenrather scarce up to date. The present study presents a deterministic mathematical model of the composting process whichallows the explanation and quantification of the main phenomena observed during the process and is based on the basiclaws of physical and biological elementary processes.The developed model sets up a methodology for the presentation of the biological phenomena involved, making possible tocouple models developed by different authors to the proposed physical model. This one considers the substrate as a porousmedia in which the three phases, solid, liquid and gaseous, are present. Mass and energy flows between them are governedby basic transfer laws. The gaseous phase is considered, in the base model, as a completely stirred mixture of oxygen, CO2,ammonia, water vapour and nitrogen, both considered as ideal gases. Its extension to the 1D space incorporates themovement of the gaseous phase due to pressure gradient, the conductive heat transfer in the solid matrix, the convectiveenergy transport, both as sensible and latent heat, and the convective mass transport of gaseous components.Three vertical static reactors at lab scale with forced aeration have been designed, built up and operated with different solidwaste mixtures in order to pick up data for checking the model predictions. Several process variables have been measuredand registered during the experiments: temperature at different points inside the reactors, oxygen and CO2 concentration inthe exhaust gases, total mass in the reactors, airflow rate, air pressure at the reactors inlet, and the settlement at differentlevels of the composting mass. The moisture content at different positions of the material has also been measured at thestart and at the end of the process.The simulations, run with a unique set of physical, stoichiometric and kinetic parameters for the experiments with differentsubstrates, reproduced satisfactorily the main trends observed by the experimental data, although these show that thehypothesis of radial symmetry in the reactors does not always holds on. A sensitivity analysis allowed the identification of thephysical parameters with greater influence on the process. A three parameter equation is proposed to describe thesettlement field inside the composting mass as a function of time. An equation linking settlement with the cumulative oxygenconsumption has also been proposed.In summary, the developed model simulates satisfactorily the main trends observed during the evolution of the observedprocess variables, integrates the different phenomena present in the composting process, and allows the quantification of itsrelative importance. The open structure of the model simplifies the incorporation of new phenomena.

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    Inventory of manure processing activities in Europe.  Open access

     Foged, Henning; Flotats Ripoll, Xavier; Bonmatí Blasi, August; Palatsi Civit, Jordi; Magrí Aloy, Albert; Schelde, Karl Martin
    Date: 2012-03-29
    Report

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    Technical Report No. I concerning “Manure Processing Activities in Europe” to the European Commission, Directorate-General Environment. Project reference: ENV.B.1/ETU/2010/0007. Publicat el 29.03.2012 a: http://ec.europa.eu/environment/water/water-nitrates/studies.html

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    End and by-products from livestock manure processing - general types, chemical composition, fertilising quality and feasibility for marketing  Open access

     Foged, Henning; Flotats Ripoll, Xavier; Bonmatí Blasi, August; Palatsi Civit, Jordi
    Date: 2012-03-29
    Report

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    Technical Report No. III concerning “Manure Processing Activities in Europe” to the European Commission, Directorate-General Environment. Project reference: ENV.B.1/ETU/2010/0007. Publicat el 20.03.2012 a: http://ec.europa.eu/environment/water/water-nitrates/studies.html

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    Manure processing technologies  Open access

     Flotats Ripoll, Xavier; Foged, Henning; Bonmatí Blasi, August; Palatsi Civit, Jordi; Magrí Aloy, Albert; Schelde, Karl Martin
    Date: 2012-03-29
    Report

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    Technical Report No. II concerning “Manure Processing Activities in Europe” to the European Commission, Directorate-General Environment. Project reference: ENV.B.1/ETU/2010/0007. Publicat el 29.03.2012 a: http://ec.europa.eu/environment/water/water-nitrates/studies.html

  • Apoyo científico-técnico Proyecto ORION

     Flotats Ripoll, Xavier
    Participation in a competitive project

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    Assessment of economic feasibility and environmental performance of manure processing technologies  Open access

     Foged, Henning; Flotats Ripoll, Xavier; Bonmatí Blasi, August; Palatsi Civit, Jordi; Magrí Aloy, Albert
    Date: 2012-03-29
    Report

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    Technical Report No. IV concerning “Manure Processing Activities in Europe” to the European Commission, Directorate-General Environment. Project reference: ENV.B.1/ETU/2010/0007. Publicat el 29.03.2012 a: ; http://ec.europa.eu/environment/water/water-nitrates/studies.html

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    Future trends on manure processing activities in Europe  Open access

     Foged, Henning; Flotats Ripoll, Xavier; Bonmatí Blasi, August
    Date: 2012-03-29
    Report

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    Technical Report No. V concerning “Manure Processing Activities in Europe” to the European Commission, Directorate-General Environment. Project reference: ENV.B.1/ETU/2010/0007. Publicat el 29.03.2012 a: http://ec.europa.eu/environment/water/water-nitrates/studies.html

  • Influence of adsorption and anaerobic granular sludge characteristics on long chain fatty acids inhibition process

     Palatsi Civit, Jordi; Affes, Rim; Fernández García, Belén; Pereira, Alcina; Alves, Madalena; Flotats Ripoll, Xavier
    Water research (Oxford)
    Date of publication: 2012-10-15
    Journal article

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  • Empirical characterisation and mathematical modelling of settlement in composting batch reactors

     Illa Alibés, Josep; Prenafeta Boldú, Francesc Xavier; Bonmatí Blasi, August; Flotats Ripoll, Xavier
    Bioresource technology
    Date of publication: 2012-01
    Journal article

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    Manure treatment strategies: an overview  Open access

     Flotats Ripoll, Xavier; Magrí Aloy, Albert
    International Symposium on Agricultural and Agroindustrial Waste Management
    Presentation's date: 2011-03-15
    Presentation of work at congresses

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    Model parameter uncertainty estimation based on Bayesian inference for activated sludge model under aerobic conditions: a comparison with a linear theory method  Open access

     Juznic Zonta, Zivko; Flotats Ripoll, Xavier; Magrí Aloy, Albert
    IWA Symposium on Systems Analysis and Integrated Assessment
    Presentation's date: 2011-06-22
    Presentation of work at congresses

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    The purpose of the study is to apply Bayesian inference in order to estimate the uncertainty in model parameters and predictions for environmental models. The analysis was based on a global optimization routine that finds good initial values for an adaptive Markov chains Monte Carlo (MCMC) algorithm that finally computes the posterior parameter distribution. A revised activated sludge model was used in order to perform a comparison between Bayesian and linear theory methods. It was observed that the linear theory method systematically underestimates the confidence intervals of the estimated model parameters because the multivariate normality assumption is violated and practical unidentifiability for some parameters occurs.

  • La implicación ciudadana como factor clave para el éxito de los procesos de digestión anaerobia

     Flotats Ripoll, Xavier; Burgos, Esther; Tey, Laura; Fresno, Joan
    Infoenviro : actualidad y tecnología de la industria medioambiental
    Date of publication: 2011-03
    Journal article

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  • Codigestion of cow and guinea pig manure in low-cost tubular digesters at high altitude

     Garfi, Marianna; Ferrer Marti, Laia; Pérez Bort, Irene; Flotats Ripoll, Xavier; Ferrer Martí, Ivet
    Ecological engineering
    Date of publication: 2011-12
    Journal article

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  • Avaluació energètica de residus industrials biodegradables a Catalunya

     Vilamajó, Clara; Flotats Ripoll, Xavier
    TECA: Tecnologia i ciència dels aliments
    Date of publication: 2011-12
    Journal article

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  • Effects of thermal pre-treatments on solid slaughterhouse waste methane potential

     Rodríguez-Abalde, Ángela; Silvestre, Gracia; Flotats Ripoll, Xavier; Fernández García, Belén
    Waste management
    Date of publication: 2011-03
    Journal article

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    The effects of thermal pre-treatments on the biogas production potential of two solid slaughterhouse waste types (poultry and piggery slaughterhouse by-products) were assessed by means of batch experiments. Both animal by-products were characterized in terms of fat, protein and carbohydrate concentrations. The selected thermal pre-treatments, pasteurization (70 ºC for 60 min) and sterilization (133 ºC and 3 bars for 20 min), are included in the current European regulations for the disposal or use of animal byproducts. The pre-treatments produced notable improvements in organic matter solubilization, but had different effects on the anaerobic bioavailability of the treated substrates. The methane yield of the initial volatile solids did not increase significantly after pre-treatment when carbohydrate concentration was high, reaching a maximum of 0:48 m3 CH4 kg1 VS for the pasteurized poultry waste. However, this yield increased by up to 52.7% after pasteurization and 66.1% after sterilization for the lower carbohydrate concentration sample (piggery waste), reaching maxima of 0.88 and 0:96 m3 CH4 kg 1 VS , respectively. The maximum methane production rates, measured as the maximum slope of the accumulated methane production curve, per unit of initial biomass content, were also different. While this rate increased by 52.6% and 211.6% for piggery waste after pasteurization and sterilization, respectively, it decreased by 43.8% for poultry waste after pasteurization with respect to untreated waste. Compounds with low biodegradability that are produced by Maillard reactions during thermal pre-treatment could explain the low bioavailability observed for waste with a high carbohydrate concentration.

  • Biogàs amb subproductes ramaders i agroalimentaris

     Flotats Ripoll, Xavier
    Cultura Energètica
    Date of publication: 2011-11
    Journal article

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  • Determinación de la mineralización del nitrógeno del purín de cerdo secado térmicamente mediante hidrólisis, incubaciones y ensayos de campo

     Ramírez Gerardo, Marithza Guadalupe
    Defense's date: 2011-07-26
    Department of Agri-Food Engineering and Biotechnology, Universitat Politècnica de Catalunya
    Theses

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    Situación y potencial de generación de biogás  Open access

     Pascual, Andrés; Ruiz, Begoña; Gómez, Paz; Flotats Ripoll, Xavier; Fernández García, Belén
    Date: 2011-07-01
    Report

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    Estudi tècnic de base per l'elaboració del PER espanyol (Plan de energías renovables) 2011-2020, relatiu al potencial de producció de biogàs a Espanya. Editat per IDAE. Estudi conjunt realitzat per AINIA (Valencia) i GIRO Centre Tecnològic (Centre UPC-IRTA).

  • Organic waste: a resource to be managed

     Flotats Ripoll, Xavier
    Public service review: European science & technology
    Date of publication: 2011-05
    Journal article

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    Simulación del proceso de digestión anaerobia y producción de biogás. Identificación de parámetros  Open access

     Flotats Ripoll, Xavier; Rodríguez-Abalde, Ángela; Palatsi Civit, Jordi; Fernández García, Belén
    Automática e instrumentación
    Date of publication: 2011-04
    Journal article

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  • Anaerobic digestion of slaughterhouse waste: Main process limitations and microbial community interactions

     Palatsi Civit, Jordi; Viñas Canals, Marc; Guivernau, Miriam; Fernández García, Belén; Flotats Ripoll, Xavier
    Bioresource technology
    Date of publication: 2011-02-01
    Journal article

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    Fresh pig/cattle slaughterhouse waste mixtures, with different lipid-protein ratios, were characterized and their anaerobic biodegradability assessed in batch tests. The resultant methane potentials were high (270–300 LCH4 kg 1 COD) making them interesting substrates for the anaerobic digestion process. However, when increasing substrate concentrations in consecutive batch tests, up to 15 gCOD kg 1, a clear inhibitory process was monitored. Despite the reported severe inhibition, related to lipid content, the system was able to recover activity and successfully degrade the substrate. Furthermore, 16S rRNA gene-based DGGE results showed an enrichment of specialized microbial populations, such as b-oxidizing/proteolitic bacteria (Syntrophomonas sp., Coprothermobacter sp. and Anaerobaculum sp.), and syntrophic methanogens (Methanosarcina sp.). Consequently, the lipid concentration of substrate and the structure of the microbial community are the main limiting factors for a successful anaerobic treatment of fresh slaughterhouse waste.

  • Biomass adaptation over anaerobic co-digestion of sewage sludge and trapped grease waste

     Silvestre Turmo, Gracia; Rodríguez-Abalde, Ángela; Flotats Ripoll, Xavier; Bonmatí Blasi, August; Fernández García, Belén
    Bioresource technology
    Date of publication: 2011-07
    Journal article

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  • Gestión y tratamiento de deyecciones ganaderas (II)

     Flotats Ripoll, Xavier
    Cría y salud
    Date of publication: 2011-06
    Journal article

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  • Gestión y tratamiento de deyecciones ganaderas (III)

     Flotats Ripoll, Xavier
    Cría y salud
    Date of publication: 2011-08
    Journal article

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  • Gestión y tratamiento de deyecciones ganaderas (I)

     Flotats Ripoll, Xavier
    Cría y salud
    Date of publication: 2011-04
    Journal article

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    Digestión anaerobia de subproductos de la industria cárnica  Open access

     Rodríguez-Abalde, Ángela; Flotats Ripoll, Xavier; Palatsi Civit, Jordi; Fernández García, Belén
    Residuos: revista técnica
    Date of publication: 2011-09
    Journal article

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  • Digestión anaerobia de subproductos de la indústria cárnica

     Palatsi Civit, Jordi; Rodríguez-Abalde, Ángela; Fernández García, Belén; Flotats Ripoll, Xavier
    Jornadas de la Red Española de Compostaje
    Presentation's date: 2010-06-01
    Presentation of work at congresses

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  • Presentación del Congreso

     Flotats Ripoll, Xavier
    International Workshop on Anaerobic Digestion of Slaughterhouse Waste
    Presentation's date: 2010-06-09
    Presentation of work at congresses

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  • Caracterización de la digestión anaerobia de proteínas de origen animal

     Flotats Ripoll, Xavier; Fernández García, Belén; Palatsi Civit, Jordi
    Jornadas de la Red Española de Compostaje
    Presentation's date: 2010-06-03
    Presentation of work at congresses

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  • Presentation of the Workshop

     Flotats Ripoll, Xavier
    International Workshop on Anaerobic Digestion of Slaughterhouse Waste
    Presentation's date: 2010-06-11
    Presentation of work at congresses

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