Mathematical Modeling of the Biogas Production in MSW Landfills. Impact of the Implementation of Organic Matter and Food Waste Selective Collection Systems

[EN] Municipal solid waste (MSW) landfills are one of the main sources of greenhouse gas emissions. Biogas is formed under anaerobic conditions by decomposition of the organic matter present in waste. The estimation of biogas production, which depends fundamentally on the type of waste deposited in the landfill, is essential when designing the gas capture system and the possible generation of energy. BIOLEACH, a mathematical model for the real-time management of MSW landfills, enables the estimation of biogas generation based on the waste mix characteristics and the local meteorological conditions. This work studies the impact of installing selective organic matter collection systems on landfill biogas production. These systems reduce the content of food waste that will eventually be deposited in the landfill. Results obtained using BIOLEACH on a set of scenarios under real climate conditions in a real landfill located in the Region of Murcia (Spain) are shown. Results demonstrate that actual CH4 and CO2 production depends fundamentally on the monthly amount of waste stored in the landfill, its chemical composition and the availability and distribution of water inside the landfill mass.Rodrigo-Ilarri, J.; Rodrigo-Clavero, M. (2020). Mathematical Modeling of the Biogas Production in MSW Landfills. Impact of the Implementation of Organic Matter and Food Waste Selective Collection Systems. Atmosphere. 11(12):1-18. https://doi.org/10.3390/atmos11121306S1181112Calculation of CH4 and CO2 Emission Rate in Kahrizak Landfill Site THROUGH LandGEM Mathematical Model. In Proceedings of the 4th World Sustainability Forumhttps://sciforum.net/conference/wsf-4Krause, M. J., W. Chickering, G., Townsend, T. G., & Reinhart, D. R. (2016). Critical review of the methane generation potential of municipal solid waste. Critical Reviews in Environmental Science and Technology, 46(13), 1117-1182. doi:10.1080/10643389.2016.1204812Allen, M. R., Braithwaite, A., & Hills, C. C. (1997). Trace Organic Compounds in Landfill Gas at Seven U.K. Waste Disposal Sites. Environmental Science & Technology, 31(4), 1054-1061. doi:10.1021/es9605634Eklund, B., Anderson, E. P., Walker, B. L., & Burrows, D. B. (1998). Characterization of Landfill Gas Composition at the Fresh Kills Municipal Solid-Waste Landfill. Environmental Science & Technology, 32(15), 2233-2237. doi:10.1021/es980004sRey, M. D., Font, R., & Aracil, I. (2013). Biogas from MSW landfill: Composition and determination of chlorine content with the AOX (adsorbable organically bound halogens) technique. Energy, 63, 161-167. doi:10.1016/j.energy.2013.09.017Harborth, P., Fuß, R., Münnich, K., Flessa, H., & Fricke, K. (2013). Spatial variability of nitrous oxide and methane emissions from an MBT landfill in operation: Strong N2O hotspots at the working face. Waste Management, 33(10), 2099-2107. doi:10.1016/j.wasman.2013.01.028Brown, K. A., & Maunder, D. H. (1994). Exploitation of landfill gas: a UK perspective. Water Science and Technology, 30(12), 143-151. doi:10.2166/wst.1994.0599Abbasi, T., Tauseef, S. M., & Abbasi, S. A. (2012). Biogas Energy. doi:10.1007/978-1-4614-1040-9El-Fadel, M., Findikakis, A. N., & Leckie, J. O. (1997). Environmental Impacts of Solid Waste Landfilling. Journal of Environmental Management, 50(1), 1-25. doi:10.1006/jema.1995.0131Levis, J. W., & Barlaz, M. A. (2011). Is Biodegradability a Desirable Attribute for Discarded Solid Waste? Perspectives from a National Landfill Greenhouse Gas Inventory Model. Environmental Science & Technology, 45(13), 5470-5476. doi:10.1021/es200721sFarquhar, G. J., & Rovers, F. A. (1973). Gas production during refuse decomposition. Water, Air, & Soil Pollution, 2(4), 483-495. doi:10.1007/bf00585092Rees, J. F. (2007). Optimisation of methane production and refuse decomposition in landfills by temperature control. 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Environmental Modelling & Software, 22(1), 59-72. doi:10.1016/j.envsoft.2005.11.003White, J. K., & Beaven, R. P. (2013). Developments to a landfill processes model following its application to two landfill modelling challenges. Waste Management, 33(10), 1969-1981. doi:10.1016/j.wasman.2012.12.006McDougall, J. (2007). A hydro-bio-mechanical model for settlement and other behaviour in landfilled waste. Computers and Geotechnics, 34(4), 229-246. doi:10.1016/j.compgeo.2007.02.004Bareither, C. A., Benson, C. H., & Edil, T. B. (2013). Compression of Municipal Solid Waste in Bioreactor Landfills: Mechanical Creep and Biocompression. Journal of Geotechnical and Geoenvironmental Engineering, 139(7), 1007-1021. doi:10.1061/(asce)gt.1943-5606.0000835Lu, S.-F., Xiong, J.-H., Feng, S.-J., Chen, H.-X., Bai, Z.-B., Fu, W.-D., & Lü, F. (2019). A finite-volume numerical model for bio-hydro-mechanical behaviors of municipal solid waste in landfills. Computers and Geotechnics, 109, 204-219. doi:10.1016/j.compgeo.2019.01.012Liu, X., Shi, J., Qian, X., Hu, Y., & Peng, G. (2011). One-dimensional model for municipal solid waste (MSW) settlement considering coupled mechanical-hydraulic-gaseous effect and concise calculation. Waste Management, 31(12), 2473-2483. doi:10.1016/j.wasman.2011.07.013Hettiarachchi, H., Meegoda, J., & Hettiaratchi, P. (2009). Effects of gas and moisture on modeling of bioreactor landfill settlement. Waste Management, 29(3), 1018-1025. doi:10.1016/j.wasman.2008.08.018Chen, Y., Xu, X., & Zhan, L. (2011). Analysis of solid-liquid-gas interactions in landfilled municipal solid waste by a bio-hydro-mechanical coupled model. Science China Technological Sciences, 55(1), 81-89. doi:10.1007/s11431-011-4667-7Staub, M. J., Gourc, J.-P., Drut, N., Stoltz, G., & Mansour, A. A. (2013). Large-Scale Bioreactor Pilots for Monitoring the Long-Term Hydromechanics of MSW. Journal of Hazardous, Toxic, and Radioactive Waste, 17(4), 285-294. doi:10.1061/(asce)hz.2153-5515.0000160Machado, S. L., Vilar, O. M., & Carvalho, M. F. (2008). Constitutive model for long term municipal solid waste mechanical behavior. Computers and Geotechnics, 35(5), 775-790. doi:10.1016/j.compgeo.2007.11.008Hettiarachchi, C. H., Meegoda, J. N., Tavantzis, J., & Hettiaratchi, P. (2007). Numerical model to predict settlements coupled with landfill gas pressure in bioreactor landfills. Journal of Hazardous Materials, 139(3), 514-522. doi:10.1016/j.jhazmat.2006.02.067Sivakumar Babu, G. L., Reddy, K. R., Chouskey, S. K., & Kulkarni, H. S. (2010). Prediction of Long-Term Municipal Solid Waste Landfill Settlement Using Constitutive Model. Practice Periodical of Hazardous, Toxic, and Radioactive Waste Management, 14(2), 139-150. doi:10.1061/(asce)hz.1944-8376.0000024Hanson, J. L., Yeşiller, N., Onnen, M. T., Liu, W.-L., Oettle, N. K., & Marinos, J. A. (2013). Development of numerical model for predicting heat generation and temperatures in MSW landfills. Waste Management, 33(10), 1993-2000. doi:10.1016/j.wasman.2013.04.003Gawande, N. A., Reinhart, D. R., & Yeh, G.-T. (2010). Modeling microbiological and chemical processes in municipal solid waste bioreactor, part I: Development of a three-phase numerical model BIOKEMOD-3P. Waste Management, 30(2), 202-210. doi:10.1016/j.wasman.2009.09.009GHOLAMIFARD, S., EYMARD, R., & DUQUENNOI, C. (2008). Modeling anaerobic bioreactor landfills in methanogenic phase: Long term and short term behaviors. Water Research, 42(20), 5061-5071. doi:10.1016/j.watres.2008.09.040Garg, A., & Achari, G. (2010). A Comprehensive Numerical Model Simulating Gas, Heat, and Moisture Transport in Sanitary Landfills and Methane Oxidation in Final Covers. Environmental Modeling & Assessment, 15(5), 397-410. doi:10.1007/s10666-009-9217-3Feng, S.-J., Lu, S.-F., Chen, H. X., Fu, W.-D., & Lü, F. (2017). Three-dimensional modelling of coupled leachate and gas flow in bioreactor landfills. Computers and Geotechnics, 84, 138-151. doi:10.1016/j.compgeo.2016.11.024Grugnaletti, M., Pantini, S., Verginelli, I., & Lombardi, F. (2016). An easy-to-use tool for the evaluation of leachate production at landfill sites. Waste Management, 55, 204-219. doi:10.1016/j.wasman.2016.03.030Lei, L., Bing, L., Qiang, X., Ying, Z., & Chun, Y. (2011). The modelling of biochemical-thermal coupling effect on gas generation and transport in MSW landfill. International Journal of Environment and Pollution, 46(3/4), 216. doi:10.1504/ijep.2011.045480Zacharof, A. I., & Butler, A. P. (2004). Stochastic modelling of landfill leachate and biogas production incorporating waste heterogeneity. Model formulation and uncertainty analysis. Waste Management, 24(5), 453-462. doi:10.1016/j.wasman.2003.09.010Pommier, S., Chenu, D., Quintard, M., & Lefebvre, X. (2007). A logistic model for the prediction of the influence of water on the solid waste methanization in landfills. Biotechnology and Bioengineering, 97(3), 473-482. doi:10.1002/bit.21241Abdallah, M., Fernandes, L., Warith, M., & Rendra, S. (2009). A fuzzy logic model for biogas generation in bioreactor landfillsA paper submitted to the Journal of Environmental Engineering and Science. Canadian Journal of Civil Engineering, 36(4), 701-708. doi:10.1139/l09-015Rodrigo-Ilarri, J., Rodrigo-Clavero, M.-E., & Cassiraga, E. (2020). BIOLEACH: A New Decision Support Model for the Real-Time Management of Municipal Solid Waste Bioreactor Landfills. International Journal of Environmental Research and Public Health, 17(5), 1675. doi:10.3390/ijerph1705167

BIOLEACH: A New Decision Support Model for the Real-Time Management of Municipal Solid Waste Bioreactor Landfills

[EN] This paper introduces BIOLEACH, a new decision support model for the real-time management of municipal solid waste bioreactor landfills that allows estimating the leachate and biogas production. Leachate production is estimated using an adaptation of the water balance equation which considers every hydrological component and the water consumed by anaerobic organic matter degradation to create biogas and the leachate recirculation flows pumped from the landfill pond under a bioreactor management scheme. Landfill gas production is estimated considering the leachate formation process as a coupled effect through the production or consumption of water. BIOLEACH uses waste production and climate data at monthly scale and computes leachate production accounting for the actual conditions inside the waste mass. Biogas production is computed simultaneously, considering the available water to adjust the chemical organic matter biodegradation. BIOLEACH is a valuable bioreactor managing tool as it allows calculating the recirculation volume of leachate that ensures optimal moisture conditions inside the waste mass and therefore maximizing biogas production. As an illustrative example of a BIOLEACH application, the model has been applied to a real landfill located in Murcia Region (Spain) showing the economic and environmental benefits derived from leachate superficial recirculation.Rodrigo-Ilarri, J.; Rodrigo-Clavero, M.; Cassiraga, EF. (2020). BIOLEACH: A New Decision Support Model for the Real-Time Management of Municipal Solid Waste Bioreactor Landfills. International Journal of Environmental research and Public Health. 17(5):1-24. https://doi.org/10.3390/ijerph17051675S124175Abd El-Salam, M. M., & I. Abu-Zuid, G. (2015). Impact of landfill leachate on the groundwater quality: A case study in Egypt. Journal of Advanced Research, 6(4), 579-586. doi:10.1016/j.jare.2014.02.003Scaglia, B., Confalonieri, R., D’Imporzano, G., & Adani, F. (2010). Estimating biogas production of biologically treated municipal solid waste. Bioresource Technology, 101(3), 945-952. doi:10.1016/j.biortech.2009.08.085GARCIADECORTAZAR, A., & MONZON, I. (2007). MODUELO 2: A new version of an integrated simulation model for municipal solid waste landfills. Environmental Modelling & Software, 22(1), 59-72. doi:10.1016/j.envsoft.2005.11.003Manna, L., Zanetti, M. C., & Genon, G. (1999). Modeling biogas production at landfill site. Resources, Conservation and Recycling, 26(1), 1-14. doi:10.1016/s0921-3449(98)00049-4Kjeldsen, P., Barlaz, M. A., Rooker, A. P., Baun, A., Ledin, A., & Christensen, T. H. (2002). Present and Long-Term Composition of MSW Landfill Leachate: A Review. Critical Reviews in Environmental Science and Technology, 32(4), 297-336. doi:10.1080/10643380290813462Omar, H., & Rohani, S. (2015). Treatment of landfill waste, leachate and landfill gas: A review. Frontiers of Chemical Science and Engineering, 9(1), 15-32. doi:10.1007/s11705-015-1501-yMambeli Barros, R., Tiago Filho, G. L., & da Silva, T. R. (2014). The electric energy potential of landfill biogas in Brazil. Energy Policy, 65, 150-164. doi:10.1016/j.enpol.2013.10.028Broun, R., & Sattler, M. (2016). A comparison of greenhouse gas emissions and potential electricity recovery from conventional and bioreactor landfills. Journal of Cleaner Production, 112, 2664-2673. doi:10.1016/j.jclepro.2015.10.010Warith, M. (2002). Bioreactor landfills: experimental and field results. Waste Management, 22(1), 7-17. doi:10.1016/s0956-053x(01)00014-9Reinhart, D. R., McCreanor, P. T., & Townsend, T. (2002). The bioreactor landfill: Its status and future. Waste Management & Research: The Journal for a Sustainable Circular Economy, 20(2), 172-186. doi:10.1177/0734242x0202000209Aguilar-Virgen, Q., Taboada-González, P., Ojeda-Benítez, S., & Cruz-Sotelo, S. (2014). Power generation with biogas from municipal solid waste: Prediction of gas generation with in situ parameters. Renewable and Sustainable Energy Reviews, 30, 412-419. doi:10.1016/j.rser.2013.10.014Ménard, J.-F., Lesage, P., Deschênes, L., & Samson, R. (2004). Comparative life cycle assessment of two landfill technologies for the treatment of municipal solid waste. The International Journal of Life Cycle Assessment, 9(6), 371-378. doi:10.1007/bf02979080Niskanen, A., Värri, H., Havukainen, J., Uusitalo, V., & Horttanainen, M. (2013). Enhancing landfill gas recovery. Journal of Cleaner Production, 55, 67-71. doi:10.1016/j.jclepro.2012.05.042Khire, M. V., & Mukherjee, M. (2007). Leachate injection using vertical wells in bioreactor landfills. Waste Management, 27(9), 1233-1247. doi:10.1016/j.wasman.2006.07.010Jain, P., Townsend, T. G., & Tolaymat, T. M. (2010). Steady-state design of vertical wells for liquids addition at bioreactor landfills. Waste Management, 30(11), 2022-2029. doi:10.1016/j.wasman.2010.02.020Feng, S.-J., Cao, B.-Y., & Xie, H.-J. (2017). Modeling of Leachate Recirculation Using Spraying–Vertical Well Systems in Bioreactor Landfills. International Journal of Geomechanics, 17(7), 04017012. doi:10.1061/(asce)gm.1943-5622.0000887Haydar, M. M., & Khire, M. V. (2005). Leachate Recirculation Using Horizontal Trenches in Bioreactor Landfills. Journal of Geotechnical and Geoenvironmental Engineering, 131(7), 837-847. doi:10.1061/(asce)1090-0241(2005)131:7(837)Reddy, K. R., Giri, R. K., & Kulkarni, H. S. (2015). Design of horizontal trenches for leachate recirculation in bioreactor landfills using two-phase modelling. 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F., & Barlaz, M. A. (2012). A review of approaches for the long-term management of municipal solid waste landfills. Waste Management, 32(3), 498-512. doi:10.1016/j.wasman.2011.11.010Kumar, S., Chiemchaisri, C., & Mudhoo, A. (2010). Bioreactor landfill technology in municipal solid waste treatment: An overview. Critical Reviews in Biotechnology, 31(1), 77-97. doi:10.3109/07388551.2010.49220

Desenvolvimento de modelos constitutivos para descrição do comportamento reológico de resíduos sólidos urbanos

Orientador: Prof. Dr. Eduardo Dell'AvanziDissertação (mestrado) - Universidade Federal do Paraná, Setor de Tecnologia, Programa de Pós-Graduaçao em Engenharia Civil. Defesa: Curitiba, 12/04/2013Bibliografia: f. 137-142Área de concentraçao: GeotecniaResumo: O estudo das propriedades dos resíduos sólidos urbanos (RSU) é essencial para garantir o melhor funcionamento de um aterro sanitário. A previsão do comportamento mecânico desses resíduos permite evitar deslizamentos de maciços de lixo e calcular os recalques das células do aterro, resultando em uma maior segurança durante a operação do aterro e um melhor aproveitamento do espaço disponível para a destinação dos resíduos. Neste trabalho propõe-se um novo modelo de previsão do comportamento mecânico dos RSU baseado no comportamento das curvas tensão x deformação resultantes de ensaios edométricos. Para calibração das equações constitutivas do modelo foram realizados ensaios edométricos com corpos de prova compostos por uma mistura de solo e coloide, visto que essa mistura simula o comportamento mecânico dos RSU e possibilita obter menores custos e amostras mais homogêneas quando comparada com amostras de resíduos. O modelo foi validado com dados encontrados na literatura para ensaios edométricos com RSU, mostrando-se condizente com a realidade e adequado para previsão do comportamento mecânico desses resíduos. As equações constitutivas propostas mostraram-se satisfatórias, sendo capazes de descrever o comportamento dos parâmetros do modelo para diversos tipos de resíduos ensaiados.Abstract: The study of municipal solid waste (MSW) characteristics, such as mechanical behavior and degradation rate, is essential to ensure a proper operation of a landfill. The prediction of the mechanical behavior of MSW contributes to avoid landfill failures, allowing the evaluation of the settlements, leachate and gas generation within the landfill's cells. As a result, more safe practice procedures can be adopted during landfill operation, including maximize the space for waste disposition. The present work proposes a new model to predict the MSW mechanical behavior based on stress-strain results of oedometer tests. To calibrate the model's constitutive equations oedometer tests were carried out with samples constituted by a mixture of soil and colloid, once this mixture simulates MSW's mechanical behavior and allows obtaining smaller costs and more homogeneous specimens when compared with MSW specimens. The model was validated with literature data for oedometer tests realized with MSW, and was proved to be consistent with validating data and appropriate to predict MSW's mechanical behavior. The proposed constitutive equations were proved to be satisfying, being capable of describing the behavior of the model's parameters for different kinds of MSW

Modelación de la producción de lixiviados que se generan en los componentes putrescibles de los residuos sólidos urbanos de Guayaquil-Ecuador

Plantea desarrollar la modelación de la producción de lixiviados generada por los componentes orgánicos putrescibles (MOP), sin adición de agua en los RSU en condiciones semejantes a las de Guayaquil. El proceso de esta investigación es cuantitativo, el método utilizado es experimental, para lo cual se utilizaron técnicas de revisión documental, y experimentación en laboratorio, lisímetros y celdas tipo. Se identificaron 18 componentes de la MOP, siendo los restos de plátano verde los de mayor proporción; en laboratorio, usando un método desarrollado por el autor en condiciones aerobias y anaerobias, se hicieron ensayos y con los resultados se generaron modelaciones de las tendencias de producción de lixiviados. También se generaron modelaciones de producción de lixiviados usando varios lisímetros con diferentes composiciones de MOP, encontrándose que con composiciones bajas de MOP, no se producen lixiviados. Para contrastar los resultados de producción se desarrollaron investigaciones en celdas experimentales de 400 toneladas con RSU que ingresan al relleno sanitario de Guayaquil (con 60% MOP), sin adición de aguas lluvias. Finalmente, se compararon los resultados de producción de lixiviados obtenidos en laboratorio (aerobios y anaerobios) con 4 lisímetros y 3 celdas experimentales.Tesi

Enhanced biodegradation of model lignocellulosic wastes in laboratory-scale bioreactors and landfills

In municipal solid waste (MSW) landfills, lignocellulosic wastes degrade slowly and cause the slow and prolonged release of biogas into the atmosphere. This release is adding to anthropogenic climate change, which is arguably the biggest challenge humankind faces today and requires immediate attention. As a solution to this problem, the overall aim of this study was to enhance biodelignification in landfills. This aim was supported by two research questions - To what extent can enzymatic & bacterial biodelignification systems breakdown lignocellulose in realistic lignin wastes, with the prospect of enhanced biogas recovery? What is the impact of flow & heterogeneity on bacterial biodelignification systems in model lignocellulose-containing bioreactor landfills? Two representative lignocellulosic wastes found largely undegraded in old landfills, i.e. newspaper and softwood, were used. Lignin peroxidase enzyme and a recently isolated lignin-degrading bacterial strain (Agrobacterium sp.) were used in tests conducted in stirred bioreactors with methanogens from sewage sludge. Lignin peroxidase resulted in ~20% enhancement in cumulative methane produced in newspaper reactors. It had a negative effect on wood (~10% decrease in total methane generated compared to controls, possibly due to simultaneous depolymerisation and repolymerisation of lignin on the surface of the wood preventing further depolymerisation). Agrobacterium sp. strain enhanced biodegradation of both wood (~20% higher release of soluble organic carbon and enhanced breakdown) and newspaper (~2-fold biogas yield). Furthermore, homogeneous and heterogeneous pore-structure configurations containing newspaper and sand were prepared to mimic old landfills. In the homogeneous case, 2-fold enhancement of biogas yield occurs, which is consistent with soluble organic carbon (sOC)/pH profiles. In the heterogeneous case, there is no significant enhancement. This is likely due to the much lower hydraulic conductivity of the newspaper/sand mixture compared to the outer sand zone, resulting in preferential flow paths through the sand. This paired with very low pH and very high sOC in the column impacts the microbial communities and their activity adversely. Overall, this thesis has surveyed the literature and identified the problem of slowly degrading newspaper and woody wastes in landfills. It has formulated research questions addressing this problem by studying accelerated degradation of these wastes, and the application of this technology to conditions close to reallife field-scale conditions (flow, heterogeneity). Enzymatic and bacterial biodelignification systems show promise under stirred-bioreactor conditions, as well as homogeneous lab-scale landfills. However, under heterogeneous conditions, the biodegradation process is more complicated

Evaluación conjunta de la producción de lixiviados y biogás en vertederos de residuos sólidos urbanos

[ES] En esta tesis doctoral se presenta BIOLEACH, un nuevo modelo de soporte a la decisión para la gestión a tiempo real de vertederos de residuos sólidos urbanos que permite la simulación conjunta de la producción de lixiviados y biogás como procesos acoplados. La estimación de la producción de lixiviados se realiza utilizando una adaptación de la ecuación de balance hídrico que considera, además de todas las componentes hidrológicas, las cantidades de agua consumidas por la degradación en fase anaerobia de la materia orgánica presente en los residuos durante el proceso de generación del biogás. El modelo considera también los volúmenes de lixiviado recirculados desde la balsa de almacenamiento hacia la superficie o el interior del vertedero, en el caso de realizar una gestión del mismo como biorreactor. La producción de biogás se estima considerando que este proceso es un proceso acoplado con el de la producción de lixiviados. BIOLEACH ha sido programado para calcular la producción de lixiviados a escala mensual, utilizando datos reales de los parámetros meteorológicos y de la producción y características de los residuos realmente depositados en el vertedero. La producción de biogás se obtiene simultáneamente, considerando el contenido en humedad realmente disponible para ajustar las reacciones estequiométricas de biodegradación de la materia orgánica. BIOLEACH es una valiosa herramienta de gestión de vertederos biorreactor y permite calcular los volúmenes de lixiviado a recircular que garantizan condiciones de humedad en el interior de la masa de residuos que maximizan la producción de biogás. Como ejemplo ilustrativo de aplicación, BIOLEACH se ha utilizado para simular el comportamiento de un vertedero real bajo diferentes escenarios de gestión. Los resultados muestran los beneficios económicos y medioambientales derivados de la recirculación de lixiviados bajo estrategias de gestión como vertedero biorreactor.[CA] En aquesta tesi doctoral es presenta BIOLEACH, un nou model de suport a la decisió per a la gestió a temps real d'abocadors de residus sòlids urbans que permet la simulació conjunta de la producció de lixiviats i biogàs com a processos aco-blats. L'estimació de la producció de lixiviats es realitza utilitzant una adaptació de l'equació de balanç hídric que considera, a més de totes les components hidrològiques, les quantitats d'aigua consumides per la degradació en fase anaeròbia de la matèria orgànica present en els residus durant el procés de generació del biogàs. El model considera també els volums de lixiviat recirculats des de la bassa cap a la superfície o l'interior de l'abocador, en el cas de realitzar una gestió del mateix com bioreactor. La producció de biogàs s'estima considerant que aquest procés és un procés acoblat amb el procés de producció de lixiviats. BIOLEACH ha estat programat per calcular la producció de lixiviats a escala mensual, utilitzant dades reals dels paràmetres meteorològics i de la producció i característiques dels residus realment dipositats a l'abocador. La producció de biogàs s'obté simultàniament, considerant el contingut en humitat realment dis-ponible per ajustar les reaccions estequiométriques de biodegradació de la matèria orgànica. BIOLEACH és una valuosa eina de gestió d'abocadors bioreactor i permet calcular els volums de lixiviat a recircular que garanteixen condicions d'humitat a l'interior de la massa de residus que maximitzen la producció de biogàs. Com a exemple il·lustratiu d'aplicació, BIOLEACH s'ha utilitzat per simular el comportament d'un abocador real sota diferents escenaris de gestió. Els resultats mostren els beneficis econòmics i mediambientals derivats de la recirculació de lixiviats sota estratègies de gestió com a bioreactor.[EN] This doctoral thesis introduces BIOLEACH, a new decision support model for the real-time management of municipal solid waste bioreactor land¿lls that allows estimating the leachate and biogas production. Leachate production is estimated using an adaptation of the water balance equation which considers every hydrological component and the water consumed by anaerobic organic matter degradation to create biogas and the leachate recirculation ¿ows pumped from the land¿ll pond under a bioreactor management scheme. Land¿ll gas production is estimated considering the leachate formation process as a coupled e¿ect through the production or consumption of water. BIOLEACH uses waste production and climate data at monthly scale and com-putes leachate production accounting for the actual conditions inside the waste mass. Biogas production is computed simultaneously, considering the available water to adjust the chemical organic matter biodegradation. BIOLEACH is a valuable bioreactor managing tool as it allows calculating the recirculation volume of leachate that ensures optimal moisture conditions inside the waste mass and therefore maximizing biogas production. As an illustrative example of a BIOLEACH application, the model has been applied to simulate the performance of a real land¿ll under different management scenarios. Results show the economic and environmental bene¿ts derived from leachate recirculation under bioreactor management schemes.Rodrigo Clavero, ME. (2020). Evaluación conjunta de la producción de lixiviados y biogás en vertederos de residuos sólidos urbanos [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/148716TESI

Análisis de la difusión de lixiviados de residuos urbanos en arcillas compactas

Tesis doctoral inédita. Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Geología y Geoquímica. Fecha de lectura: 01-07-201

Interaktion von Abbauprozessen, Verformung und Transportprozessen in Siedlungsabfalldeponien

In this thesis a model for the complex interactions between deformation, degradation and transport processe in municipal solid waste landfills is presented. Key aspects of the model are a joint continuum mechanical framework and a monolithic solution of the governing equations within the Theory of Porous Media. Interactions are considered by coupling the governing physical fields over the domain of a representative elementary volume via selected state variables. A simplified two-stage degradation model describes anaerobic biological processes. Heat generation from exothermic reactions is considered. Transport of the leachate and the landfill gas are described by means of a generalised Darcy law and the influence of deformation on the hydraulic properties is considered. In cooperation with Edinburgh Napier University experiments on the moisture retention properties of waste are performed. The model for stress-deformation behaviour includes a novel creep model which combines stress-dependency of creep rate with density-dependency. Via the solid dry bulk density, the creep rate is coupled to degradation which enables description of degradation-induced settlements. The concept of effective stress is included in the mechanical equilibrium and thus a separate description of separate settlement phenomena is enabled. A combination of the Finite-Element method and the Box method in an ALE formulation is applied for spatial discretisation of the governing physical fields. The model is verified and validated against a benchmark for multiphase flow and a waste lysimeter experiment. Analyses of a landfill structure show the capabilities of the model in the estimation of long-term settlements, in the description of a gas extraction system and in modelling of an infiltration layer.In dieser Arbeit wird ein Modell für die simultane Kopplung des Spannungsverformungsverhaltens, der Abbauprozesse und der Transportprozesse in Deponien vorgestellt. Das Modell ist im Rahmen der Theorie Poröser Medien entwickelt. Die Interaktionen sind mit der Kopplung der physikalischen Felder über ein repräsentatives Elementarvolumen berücksichtigt. Ein zweistufiges Abbaumodell beschreibt den anaeroben Abbau der Organik und die Wärmeentwicklung infolge exothermer Reaktionen. Mehrphasentransport und physikalische Austauschprozesse sind beschrieben. In Kooperation mit der Edinburgh Napier University werden Versuche zum Wasserrückhaltevermögen von Abfall durchgeführt. Ein Kompaktionsmodell wird vorgestellt, bei dem die Kompaktionsrate nicht nur von der Spannung, sondern auch von der Dichte der festen Substanz abhängt. Dies ermöglicht die direkte Kopplung an das Reaktionsmodell und damit die Beschreibung abbauinduzierter Setzungen. Der Einfluss der Verformung auf die Porosität und die Permeabilität sind berücksichtigt. Das Konzept der effektiven Spannungen erlaubt zusammen mit dem Kompaktionsmodell die getrennnte Beschreibung von Setzungsmechanismen. Für die räumliche Diskretisierung der Bilanzgleichungen wird eine Kombination der Finite-Elemente Methode und des Box-Verfahrens verwendet. Das Modell wird anhand von Laborversuchen validiert. Anwendungen auf Deponiestrukturen beinhalten die Langzeit-Prognose von Setzungen, die Untersuchung eines Gasfassungsystems und die Modellierung der aktiven Bewässerung auf Deponien zur Beschleunigung der Abbauprozesse

Aterro de resíduos urbanos e a sua sustentabilidade ambiental: Estratégias para reduzir emissões a longo prazo

Numa ótica da sustentabilidade ambiental de aterros de resíduos urbanos, é fundamental controlar as suas emissões a longo prazo, pois a produção de lixiviados e biogás gerados podem prolongar-se por várias décadas. O tempo de vida das barreiras e sistemas artificiais de proteção poderão revelar-se mais curtos, pelo que, após o período previsto de monitorização pós-encerramento, existe uma forte probabilidade de ocorrer contaminação ambiental do ar, do solo e, das águas subterrâneas e superficiais. Deste modo, os encargos ambientais e económicos de remediação ambiental afetarão e terão de ser custeados pelas gerações seguintes. Para controlar e reduzir as emissões a longo prazo, importa acelerar a biodegradação dos resíduos e, assim, diminuir o tempo de estabilização do aterro de resíduos urbanos. Várias soluções têm sido investigadas e implementadas a nível internacional que incluem quer a introdução controlada de líquidos quer a introdução de ar no aterro. Para avaliar o comportamento daqueles aterros, em Portugal, utilizou-se um conjunto de dados históricos para analisar os efeitos de parâmetros associados à idade, ao clima, à dimensão e à recirculação de concentrado de osmose inversa, através de análise estatística e modelos de aprendizagem automática. Identificaram-se as variáveis ambientais e económicas que conduzem às melhores soluções operacionais e desenvolveu-se um potencial modelo conceptual (MaterS), que permite simular de forma probabilística as opções de intervenção no aterro de RU, durante o seu ciclo de vida. Os resultados desta investigação são um importante contributo para os gestores e decisores (nacionais e internacionais) na análise prévia das medidas operacionais e ambientais mais sustentáveis de longo prazo a tomar e, numa perspetiva mais ampla, no contexto da avaliação da legislação de aterro de resíduos urbanos.From the point of view of the environmental sustainability of urban waste landfills, it is essential to control their emissions over the long term, as the production of leachate and biogas can last for several decades. The lifespan of barriers and artificial protection barriers may be shorter, so that after the aftercare period, there is a high probability of environmental contamination of air, soil, groundwater, and surface water. Thus, the environmental and economic burden of environmental remediation will affect and must be borne by subsequent generations. To control and reduce emissions in the long term, it is important to accelerate the biodegradation of waste and thus reduce the stabilisation time of the urban waste landfill. Various solutions have been investigated and implemented internationally that include both the controlled introduction of liquids and the introduction of air into the landfill. To assess the behaviour of these landfills in Portugal, a set of historical data from was used to analyse the effects of parameters associated with age, climate, size, and the recirculation of reverse osmosis concentrate, using statistical analysis and machine-learning models. The environmental and economic variables that lead to the best operational solutions have been identified, and a potential conceptual model (MaterS) has been developed, to probabilistically simulate the intervention options for the urban waste landfill during its life cycle. The results of this research are an important contribution to managers and decision-makers (national and international) in analysing the most sustainable long-term operational and environmental options to be taken and, from a broader perspective, in the context of evaluating landfill legislation