Risk of Leaching in Soils Amended by Compost and digestate from Municipal Solid Waste

New European directives have proposed the direct application of compost and digestate produced from municipal solid wastes as organic matter sources in agricultural soils. Therefore information about phosphorus leaching from these residues when they are applied to the soil is increasingly mportant. Leaching experiments were conducted to determine the P mobility in compost and digestate mixtures, supplying equivalent amounts to 100 kg P ha?1 to three different types of soils. The tests were performed in accordance with CEN/TS 14405:2004 analyzing the maximum dissolved reactive P and the kinetic rate in the leachate. P biowaste fractionation indicated that digestate has a higher level of available P than compost has. In contrast, P losses in leaching experiments with soil-compost mixtureswere higher than in soil-digestate mixtures. For bothwastes, therewas no correlation between disolved reactive P lost and the water soluble P.The interaction between soil and waste, the long experimentation time, and the volume of leachate obtained caused the waste?s wettability to become an influential parameter in P leaching behavior. The overall conclusion is that kinetic data analysis provides valuable information concerning the sorption mechanism that can be used for predicting the large-scale behavior of soil systems.

Impact of a value chain approach on the sustainability of solid waste management in Mukuru Kwa njenga informal settlements Nairobi, Kenya

En un mundo altamente urbanizado, la gestión de residuos sólidos es un problema primordial en toda ciudad. Las ciudades de paises en desarrollo deben además afrontar retos que no afectan a las ciudades de paises desarrollados. En los paises en desarrollo muchas municipalidades sufren un crecimiento descontrolado de los asentamientos informales sin planificación urbana que hace muy complicada una adecuada gestión de los residuos sólidos urbanos, situación que se agrava al no contar estas con suficientes recursos económicos para llevar a cabo su responsabilidad en cuanto a provisión del sevicio básico de recogida de residuos. La provisión de servicio de recogida de residuos por parte de SHGs (grupos de ayuda comunitarios) en estos asentamientos informales puede ayudar a resolver algunos de estos problemas. Para que esta oportunidad sea completamente explotada, los ingresos de estos grupos deben ser garantizados, teniendo en cuenta que la sostenibilidad de estos grupos depende enteramente de ello. Este estudio pretende averiguar cómo un enfoque de cadena de valor puede mejorar la sostenibilidad de la gestión de residuos sólidos, permitiendo asegurar los ingresos de los recolectores informales de residuos. El estudio propondrá después de analizado el actual sistema, mejoras que permitan desarrollar un medio ambiente saludable en los asentamientos informales donde se desarrolla el estudio. Para alcanzar este objetivo, se ha desarrollado una investigación específica en Nairobi (Kenia) en el asentamiento precario de Mukuru Kwa Njenga, analizando los distintos aspectos relevantes que tienen influencia en una gestión integrada de residuos sólidos y las relaciones entre los distintos actores que tienen influencia en la misma.

Yield, nutrient utilization and soil properties in a melon crop amended with wine-distillery waste

In Spain, large quantities of wine are produced every year (3,339,700 tonnes in 2011) (FAO, 2011) with the consequent waste generation. During the winemaking process, solid residues like grape stalks are generated, as well as grape marc and wine lees as by-products. According to the Council Regulation (EC) 1493/1999 on the common organization of the wine market, by-products coming from the winery industry must be sent to alcohol-distilleries to generate exhausted grape marc and vinasses. With an adequate composting treatment, these wastes can be applied to soils as a source of nutrients and organic matter. A three-year field experiment (2011, 2012 and 2013) was carried out in Ciudad Real (central Spain) to study the effects of wine-distillery waste compost application in a melon crop (Cucumis melo L.). Melon crop has been traditionally cultivated in this area with high inputs of water and fertilizers, but no antecedents of application of winery wastes are known. In a randomized complete block design, four treatments were compared: three compost doses consisted of 6.7 (D1), 13.3 (D2) and 20 t compost ha-1 (D3), and a control treatment without compost addition (D0). The soil was a shallow sandy-loam (Petrocalcic Palexeralfs) with a depth of 0.60 m and a discontinuous petrocalcic horizon between 0.60 and 0.70 m, slightly basic (pH 8.4), poor in organic matter (0.24%), rich in potassium (410 ppm) and with a medium level of phosphorus (22.1 ppm). During each growing period four harvests were carried out and total and marketable yield (fruits weighting <1 kg or visually rotten were not considered), fruit average weight and fruit number per plant were determined. At the end of the crop cycle, four plants per treatment were sampled and the nutrient content (N, P and K) was determined. Soil samplings (0-30 cm depth) were carried before the application of compost and at the end of each growing season and available N and P, as well as exchangeable K content were analyzed. With this information, an integrated analysis was carried out with the aim to evaluate the suitability of this compost as organic amendment.

Effects of biochar prepared from organic waste on soil properties

Biochar is a carbon-rich solid obtained by the thermal decomposition of organic matter under a limited supply of oxygen and at relatively low temperatures. Biochar can be prepared from the pyrolysis of different organic feed- stocks, such as wood and biomass crops, agricultural by-products, different types of waste or paper industry waste materials . The pyrolysis procedure of waste, i.e. sewage sludge, has mainly two advantages, firstly, it removes pathogens from waste and, secondly, biochar can reduce the leaching of heavy metals present in raw sewage sludge. This trend of the use of waste material as feedstocks to the preparation of biochar is increasing in the last years due to industrial development and economic growth imply an increase in waste generation. The application of biochar may have positive effects on soil physical properties as water holding capacity and structure or on soil biological activity and soil quality. Also, biochar can be used to remove water pollutants and can be used in multiple ways in soil remediation due to its adsorption of pesticides or metals. Also, biochar contribute to carbon sequestration due to carbon stability of biochar materials. The objective of this presentation is to review the positive effects of the biochar prepared from organic waste on soil properties.

Legal Aspects which Implement Good Practice Measures in the Management of Construction and Demolition Waste

The construction industry, one of the most important ones in the development of a country, generates unavoidable impacts on the environment. The social demand towards greater respect for the environment is a high and general outcry. Therefore, the construction industry needs to reduce the impact it produces. Proper waste management is not enough; we must take a further step in environmental management, where new measures need to be introduced for the prevention at source, such as good practices to promote recycling. Following the amendment of the legal frame applicable to Construction and Demolition Waste (C&D waste), important developments have been incorporated in European and International laws, aiming to promote the culture of reusing and recycling. This change of mindset, that is progressively taking place in society, is allowing for the consideration of C&D waste no longer as an unusable waste, but as a reusable material. The main objective of the work presented in this paper is to enhance C&D waste management systems through the development of preventive measures during the construction process. These measures concern all the agents intervening in the construction process as only the personal implication of all of them can ensure an efficient management of the C&D waste generated. Finally, a model based on preventive measures achieves organizational cohesion between the different stages of the construction process, as well as promoting the conservation of raw materials through the use and waste minimization. All of these in order to achieve a C&D waste management system, whose primary goal is zero waste generation

Use of alternative fuels obtained from renewable sources in brayton cycles

Analysis and simulation of the behaviour of gas turbines for power generation using different nonconventional fuels obtained from different renewable sources are presented. Three biomass-tobiofuel processes are considered: anaerobic digestion of biomass (biogas), biomass gasification (synthesis gas) and alcoholic fermentation of biomass and dehydration (bioethanol), each of them with two different biomass substrates (energy crops and municipal solid waste) as input. The gas turbine behaviour in a Brayton cycle is simulated both in an isolated operation and in combined cycle. The differences in gas turbine performance when fired with the considered biofuels compared to natural gas are studied from different points of view related with the current complex energetic context: energetic and exergetic efficiency of the simple/combined cycle and CO2 emissions. Two different tools have been used for the simulations, each one with a different approach: while PATITUG (own software) analyses the behaviour of a generic gas turbine allowing a total variability of parameters, GT-PRO (commercial software) is more rigid, albeit more precise in the prediction of real gas turbine behaviour. Different potentially interesting configurations and its thermodynamic parameters have been simulated in order to obtain the optimal range for all of them and its variation for each fuel.

Use of alternative fuels obtained from renowable sources in Brayton cycles

Analysis and simulation of the behaviour of gas turbines for power generation using different nonconventional fuels obtained from different renewable sources are presented. Three biomass-tobiofuel processes are considered: anaerobic digestion of biomass (biogas), biomass gasification (synthesis gas) and alcoholic fermentation of biomass and dehydration (bioethanol), each of them with two different biomass substrates (energy crops and municipal solid waste) as input. The gas turbine behaviour in a Brayton cycle is simulated both in an isolated operation and in combined cycle. The differences in gas turbine performance when fired with the considered biofuels compared to natural gas are studied from different points of view related with the current complex energetic context: energetic and exergetic efficiency of the simple/combined cycle and CO2 emissions. Two different tools have been used for the simulations, each one with a different approach: while PATITUG (own software) analyses the behaviour of a generic gas turbine allowing a total variability of parameters, GT-PRO (commercial software) is more rigid, albeit more precise in the prediction of real gas turbine behaviour. Different potentially interesting configurations and its thermodynamic parameters have been simulated in order to obtain the optimal range for all of them and its variation for each fuel.

Plaster reinforcement with fibers by mineral wool obtained from the recycle of construction and demolition waste

The use of mineral wool is becoming more widespread due to increased acoustic and thermal demands of Spanish Technical Building Code. This increase affects both in rehabilitation and new construction projects. Therefore, waste generation of this type of insulating material is having more importance. The main objective of this research is to study the possibility of recycling fiber obtained from mineral wool of the C&DW as an alternative material to chopped glass fibers that are currently used as reinforcing elements in the prefabricated plaster. To achieve this objective, series are made of plaster E-35 additived with rock wool residue and glass wool residue at different rates of addition. These series are repeated by changing the additive by E fiberglass (length of 25mm) to make a comparative analysis with respect to the series additived with mineral wool waste. All the series are subjected to the test to determine Shore C surface hardness and mechanical testing to determine the compressive and flexural strength. From the results it can be concluded that: with rock wool residue, increases Shore C hardness up to 15% with respect to the glass fiber and 9% with respect to the glass wool, with a percentage of addition 2%. With rock wool residue, weight is decreased by 5% with respect to the glass fiber and 4% with respect to the glass wool waste, with an addition percentage of 4%. For an addition rate of 4%, results in the flexural strength test with fiberglass are 85% higher than those obtained with glass wool residue. However, for a percentage of 1% addition, the results obtained with glass wool residue are 35% higher than those obtained with fiberglass. For an addition rate of 3% results in the compressive strength test with fiberglass are 54% lower than those obtained with rock wool waste and 70% lower than those obtained with glass wool waste. Comparing the two mineral wools, it can be concluded that up to 3% of the addition, the glass wool series results obtained are 10% higher than those additived with rock wool. However, higher percentages of addition show that the results obtained with rock wool are 35% higher than those obtained with glass wool. The general conclusion is that the series additived with mineral wool from C&DW show better results in tests than the ones used nowadays as plaster reinforcement.

Factors impacting the market share of Construction and Demolition (C&D) Waste recycling solutions

Current EU Directives force the Member States to assure by 2020 that 70% of the Construction and Demolition (C&D) waste is recovered instead of landfilled. While some countries have largely achieved this target, others still have a long way to go. For better understanding the differences arising from local disparities, six factors related to technical, economic, legislative and environmental aspects have been identified as crucial influences in the market share of C&D waste recycling solutions. These factors are able to identify the causes that limit the recycling rate of a certain region. Moreover, progress towards an efficient waste management can vary through the improvement of a single factor. This study provides the background for further fine-tuning the factors and their combination into a mathematical model for assessing the market share of C&D recycling solutions.

Approach to the use of indicators for the assessment of the environmental level of construction products

The European construction industry is supposed to consume the 40% of the natural European resources and to generate the 40% of the European solid waste. Conscious of the great damage being suffered by the environment because of construction activity, this work tries to provide the building actors with a new tool to improve the current situation. The tool proposed is a model for the comprehensive evaluation of construction products by determining their environmental level. In this research, the environmental level of a construction product has been defined as its quality of accomplishing the construction requirements needed by causing the minimum ecological impact in its surrounding environment. This information allows building actors to choose suitable materials for building needs and also for the environment, mainly in the project stage or on the building site, contributing to improve the relationship between buildings and environment. For the assessment of the environmental level of construction products, five indicators have been identified regarding their global environmental impact through the product life cycle: CO2 emissions provoked during their production, volume and toxicity of waste generated on the building site, durability and recycling capacity after their useful life. Therefore, the less environmental impact one construction product produces, the higher environmental level performs. The model has been tested in 30 construction products that include environmental criteria in their description. The results obtained will be discussed in this article. Furthermore, this model can lay down guidelines for the selection of ecoefficient construction products and the design of new eco-competitive and eco-committed ones

Propuesta metodológica de aplicación sectorial de Análisis de Ciclo de Vida (ACV) para la evaluación ambiental de la edificación en España

La aplicación de criterios de sostenibilidad ha de entenderse como el procedimiento esencial para la necesaria reconversión del sector de la construcción, que movilizando el 10% de la economía mundial, representa más de la tercera parte del consumo mundial de recursos, en torno al 30-40% del consumo energético y emisiones de gases de efecto invernadero, 30-40% de la generación de residuos y el 12% de todo el gasto en agua dulce del planeta. La presente investigación se enmarca en una estrategia general de promover la evaluación de la sostenibilidad en la edificación en el contexto español, dando un primer paso centrado en la evaluación del comportamiento ambiental. El hilo conductor de la investigación parte de la necesidad de establecer un marco teórico de sostenibilidad, que permita clarificar conceptos y definir criterios de valoración adecuados. Como siguiente paso, la investigación se dirige a la revisión del panorama internacional de normativa e instrumentos voluntarios, con el objetivo de clarificar el difuso panorama que caracteriza a la sostenibilidad en el sector de la edificación en la actualidad y enmarcar la investigación en un contexto de políticas y programaciones ya existentes. El objetivo principal reside en el planteamiento de una metodología de evaluación de los aspectos o impactos ambientales asociados al ciclo de vida de la edificación, aplicable al contexto español, como una de las tres dimensiones que constituyen los pilares básicos de la sostenibilidad. Los ámbitos de evaluación de los aspectos sociales y económicos, para los que no existe actualmente un grado de definición metodológico suficientemente congruente, son adicionalmente examinados, de cara a ofrecer una visión holística de la evaluación. Previo al desarrollo de la propuesta, se aborda, en primer lugar, la descripción de las características básicas y limitaciones de la metodología de Análisis de Ciclo de Vida (ACV), para posteriormente proceder a profundizar en el estado del arte de aplicación de ACV a la edificación, realizando una revisión crítica de los trabajos de investigación que han sido desarrollados en los últimos años. Esta revisión permite extraer conclusiones sobre su grado de coherencia con el futuro entorno normativo e identificar dos necesidades prioritarias de actuación: -La necesidad de armonización, dadas las fuertes inconsistencias metodológicas detectadas, que imposibilitan la comparación de los resultados obtenidos en los trabajos de evaluación. -La necesidad de simplificación, dada la complejidad inherente a la evaluación, de modo que, manteniendo el máximo rigor, sea viable su aplicación práctica en el contexto español. A raíz de la participación en los trabajos de desarrollo normativo a nivel europeo, se ha adquirido una visión crítica sobre las implicaciones metodológicas de la normativa en definición, que permite identificar la hoja de ruta que marcará el escenario europeo en los próximos años. La definición de la propuesta metodológica integra los principios generales de aplicación de ACV con el protocolo metodológico establecido en la norma europea, considerando adicionalmente las referencias normativas de las prácticas constructivas en el contexto español. En el planteamiento de la propuesta se han analizado las posibles simplificaciones aplicables, con el objetivo de hacer viable su implementación, centrando los esfuerzos en la sistematización del concepto de equivalente funcional, el establecimiento de recomendaciones sobre el tipo de datos en función de su disponibilidad y la revisión crítica de los modelos de cálculo de los impactos ambientales. Las implicaciones metodológicas de la propuesta se describen a través de una serie de casos de estudio, que ilustran su viabilidad y las características básicas de aplicación. Finalmente, se realiza un recorrido por los aspectos que han sido identificados como prioritarios en la conformación del escenario de perspectivas futuras, líneas de investigación y líneas de acción. Abstract Sustainability criteria application must be understood as the essential procedure for the necessary restructuring of the construction sector, which mobilizes 10% of the world economy, accounting for more than one third of the consumption of the world's resources, around 30 - 40% of energy consumption and emissions of greenhouse gases, 30-40% of waste generation and 12% of all the fresh water use in the world. This research is in line with an overall strategy to promote the sustainability assessment of building in the Spanish context, taking a first step focused on the environmental performance assessment. The thread of the present research sets out from the need to establish a theoretical framework of sustainability which clarifies concepts and defines appropriate endpoints. As a next step, the research focuses on the review of the international panorama regulations and voluntary instruments, with the aim of clarifying the fuzzy picture that characterizes sustainability in the building sector at present while framing the research in the context of existing policies and programming. The main objective lies in the approach of a methodology for the assessment of the environmental impacts associated with the life cycle of building, applicable to the Spanish context, as one of the three dimensions that constitute the pillars of sustainability. The areas of assessment of social and economic issues, for which there is currently a degree of methodological definition consistent enough, are further examined, in order to provide a holistic view of the assessment. The description of the basic features and limitations of the methodology of Life Cycle Assessment (LCA) are previously addressed, later proceeding to deepen the state of the art of LCA applied to the building sector, conducting a critical review of the research works that have been developed in recent years. This review allows to establish conclusions about the degree of consistency with the future regulatory environment and to identify two priority needs for action: - The need for harmonization, given the strong methodological inconsistencies detected that prevent the comparison of results obtained in assessment works. - The need for simplification, given the inherent complexity of the assessment, so that, while maintaining the utmost rigor, make the practical application feasible in the Spanish context. The participation in the work of policy development at European level has helped to achieve a critical view of the methodological implications of the rules under debate, identifying the roadmap that will mark the European scene in the coming years. The definition of the proposed methodology integrates the general principles of LCA methodology with the protocol established in the European standard, also considering the regulatory standards to construction practices in the Spanish context. In the proposed approach, possible simplifications applicable have been analyzed, in order to make its implementation possible, focusing efforts in systematizing the functional equivalent concept, establishing recommendations on the type of data based on their availability and critical review of the calculation models of environmental impacts. The methodological implications of the proposal are described through a series of case studies, which illustrate the feasibility and the basic characteristics of its application. Finally, the main aspects related to future prospects, research lines and lines of action that have been identified as priorities are outlined.

Sistema de gestión de residuos de construcción y demolición en obras de edificación residencial. Buenas prácticas en la ejecución de obra

En el sector de la edificación, las grandes constructoras comienzan a considerar aspectos medioambientales, no limitándose a lo establecido por la legislación vigente, y buscando la implementación de buenas prácticas. Si bien este hecho es una realidad para las grandes empresas constructoras, todavía falta que la gran mayoría de las empresas del sector (pequeñas y medianas) adopten ésta tendencia. En este sentido, las publicaciones y estadísticas consultadas revelan que el sector de la construcción sigue siendo el sector con menor número de Sistemas de Gestión Ambiental (SGA) certificados en comparación con otros sectores industriales, debido principalmente a las peculiaridades de su actividad. Por otra parte, el sector de la construcción genera grandes cantidades de residuos de construcción y demolición (RCD). Aunque, en los últimos años la actividad de la construcción ha disminuido, debido a la crisis económica del país, no hay que olvidar todos los problemas causados por este tipo de residuos, o mejor dicho, por su gestión. La gestión de los RCD actual está lejos de alcanzar la meta propuesta en la Directiva Marco de Residuos (DMR), la cual exige un objetivo global para el año 2020 en el que el 70% de todos los RCD generados deberán ser reciclados en los países de la UE. Pero, la realidad es que sólo el 50% de la RCD generados en la Unión Europea se recicla. Por este motivo, en los últimos años se ha producido una completa modificación del régimen jurídico aplicable a los RCD, incorporando importantes novedades a nuestro ordenamiento interno como son: la redacción de un Estudio de gestión de RCD (en fase de diseño) y un Plan de gestión de RCD (en fase de ejecución). Entre estas medidas destaca el poder conocer, con la antelación suficiente, la cantidad y el momento en que los RCD son generados, para así poder planificar la gestión más adecuada para cada categoría de RCD. Es por ello que el desarrollo de cualquier instrumento que determine la estimación de RCD así como iniciativas para su control debe ser considerado como una herramienta para dar respuestas reales en el campo de la sostenibilidad en la edificación. Por todo lo anterior, el principal objetivo de la Tesis Doctoral es mejorar la gestión actual de los RCD, a través de la elaboración e implementación en obra de un Sistema de gestión de RCD en fase de ejecución que podrá ser incluido en el Sistema de Gestión Ambiental de las empresas constructoras. Para ello, se ha identificado la actividad que más residuo genera, así como las diferentes categorías de RCD generadas durante su ejecución, a través del análisis de nueve obras de edificación de nueva planta. Posteriormente, se han determinado y evaluado, en función de su eficacia y viabilidad, veinte buenas prácticas encaminadas a reducir la generación de RCD. También, se han identificado y evaluado, en función de su coste económico, cinco alternativas de gestión para cada categoría de RCD generada. Por último, se ha desarrollado e implementado un Sistema de Gestión de RCD en una empresa de construcción real. En definitiva, el Sistema de Gestión de RCD propuesto contiene una herramienta de estimación de RCD y también proporciona una relación de buenas prácticas, según su viabilidad y eficacia, sobre los aspectos más significativos en cuanto a la gestión de RCD se refiere. El uso de este Sistema de gestión de RCD ayudará a los técnicos de la construcción en el desarrollo de los documentos "Estudio de gestión de RCD " y "Plan de gestión de RCD " - requeridos por ley -. Además, el Sistema promueve la gestión ambiental de la empresa, favoreciendo la cohesión del proceso constructivo, estableciendo responsabilidades en el ámbito de RCD y proporcionando un mayor control sobre el proceso. En conclusión, la implementación de un sistema de gestión de RCD en obra ayuda a conseguir una actividad de edificación, cuyo principal objetivo sea la generación de residuos cero. ABSTRACT Currently, in the building sector, the main construction companies are considering environmental issues, not being limited to the current legislation, and seeking the implementation of good practices. While this fact is a reality for large construction companies, still the vast majority of construction companies (small and medium enterprises) need to accept this trend. In this sense, official publications and statistics reveal that the construction sector remains with the lowest number of certified Environmental Management Systems (EMS) compared to other industrial sectors, mainly due to the peculiarities of its activity. Moreover, the construction industry in Spain generates large volumes of construction and demolition waste (CDW) achieving a low recycling rate compared to other European Union countries and to the target set for 2020. Despite the complete change in the legal regime for CDW in Spain, there are still several difficulties for their application at the construction works. Among these difficulties the following can be highlighted: onsite segregation, estimating CDW generation and managing different CDW categories. Despite these difficulties, the proper CDW management must be one of the main aspects considered by construction companies in the EMS. However, at present the EMS used in construction companies consider very superficially CDW management issues. Therefore, current EMS should go a step further and include not only procedures for managing CDW globally, but also specific procedures for each CDW category, taking into account best practices for prevention, minimization and proper CDW management in order to achieve building construction works with zero waste generation. The few scientific studies analysing EMS implementation in construction enterprises focus on studying the benefits and barriers of their implementation. Despite the drawbacks found, implementing an EMS would bring benefits such as improving the corporate image in relation to the environment, ensuring compliance with the law or reducing environmental risks. Also, the international scientific community has shown great interest in defining models to estimate in advance the CDW that will be generated during the building construction or rehabilitation works. These studies analyse the overall waste generation and its different CDW categories. However, despite the many studies found on CDW quantification, analysing its evolution throughout the construction activities is a factor that must be further studied and discussed in greater depth, as results would be of great significance when planning the CDW management. According to the scientific studies analysing the implementation of good environmental practices in construction sites, it seems that, in general, the CDW collection system is done in a decentralized manner by each subcontracted company. In addition, the corporate image generated when poor practices are done may adversely affect the company's reputation and can result in loss of contracts. Finally, although there are numerous guides and manuals of good practices for CDW management, no references have been found implementing these measures in the Environmental Management System of the construction companies. From all the above, this thesis aims to provide answers to reduce the environmental impact caused by CDW generation in building construction works, in order to get a building process with zero waste generation. In this sense, is essential to generate new knowledge in order to implement a system which can carry out comprehensive management of CDW generated onsite, at the design stage until the end of its life cycle, taking into account both technical and economic criteria. Therefore, the main objective of this thesis is to define and implement a CDW management system for residential building construction works, helping construction agents not only to manage the CDW in accordance with current legislation, but also minimizing their generation on site by applying best practices, resulting in achieving the goal of zero waste in building works.

Carbon dioxide emissions from semi-arid soils amended with biochar alone or combined with mineral and organic fertilizers

Semi-arid soils cover a significant area of Earth s land surface and typically contain large amounts of inorganic C. Determining the effects of biochar additions on CO2 emissions fromsemi-arid soils is therefore essential for evaluating the potential of biochar as a climate change mitigation strategy. Here, we measured the CO2 that evolved from semi-arid calcareous soils amended with biochar at rates of 0 and 20 t ha?1 in a full factorial combination with three different fertilizers (mineral fertilizer, municipal solid waste compost, and sewage sludge) applied at four rates (equivalent to 0, 75, 150, and 225 kg potentially available N ha?1) during 182 days of aerobic incubation. A double exponential model, which describes cumulative CO2 emissions from two active soil C compartments with different turnover rates (one relatively stable and the other more labile), was found to fit verywell all the experimental datasets. In general, the organic fertilizers increased the size and decomposition rate of the stable and labile soil C pools. In contrast, biochar addition had no effects on any of the double exponential model parameters and did not interact with the effects ascribed to the type and rate of fertilizer. After 182 days of incubation, soil organic and microbial biomass C contents tended to increase with increasing the application rates of organic fertilizer, especially of compost, whereas increasing the rate of mineral fertilizer tended to suppress microbial biomass. Biochar was found to increase both organic and inorganic C contents in soil and not to interactwith the effects of type and rate of fertilizer on C fractions. As a whole, our results suggest that the use of biochar as enhancer of semi-arid soils, either alone or combined with mineral and organic fertilizers, is unlikely to increase abiotic and biotic soil CO2 emissions.

Desarrollo de conglomerados con la incorporación de cenizas volantes procedentes de la incineración de residuos sólidos urbanos

Esta tesis presenta los resultados de la investigación realizada sobre la inertización de cenizas volantes procedentes de residuos sólidos urbanos y su posterior encapsulación en distintas matrices de mortero. Durante el proceso de inertización, se ha logrado la inertización de éste residuo tóxico y peligroso (RTP) y también su valorización como subproducto. De esta forma se dispone de nueva “materia prima” a bajo coste y la eliminación de un residuo tóxico y peligroso con la consiguiente conservación de recursos naturales alternativos. La caracterización química de las cenizas analizadas refleja que éstas presentan altas concentraciones de cloruros, Zn y Pb. Durante la investigación se ha desarrollado un proceso de inertización de las cenizas volantes con bicarbonato sódico (NaHCO3) que reduce en un 99% el contenido en cloruros y mantiene el pH en valores óptimos para que la concentración de los metales pesados en el lixiviado sea mínima debido a su estabilización en forma de carbonatos insolubles. Se han elaborado morteros con cuatro tipos distintos de cementos (CEM-I, CEM-II, CAC y CSA) incorporando cenizas volantes inertizadas en una proporción igual a un 10% en peso del árido utilizado. Los morteros ensayados abarcan distintas dosificaciones tanto en la utilización de áridos con distintos diámetros (0/2 y 0/4), como en la relación cemento/árido (1/1 y 1/3). Se han obtenido las propiedades físicas y mecánicas de estos morteros mediante ensayos de Trabajabilidad, Estabilidad Dimensional, Carbonatación, Porosidad y Resistencias Mecánicas. De igual forma, se presentan resultados de ensayos de lixiviación de Zn, Pb, Cu y Cd, sobre probetas monolíticas de los morteros con los mejores comportamientos físico/mecánicos, donde se ha analizado el contenido en iones de dichos metales pesados lixiviados mediante determinación voltamperométrica de redisolución anódica Se concluye que todos los morteros ensayados son técnicamente aceptables, siendo los más favorables los elaborados con Cemento de Sulfoaluminato de Calcio (CSA) y con Cemento de Aluminato de Calcio (CAC). En este último caso, se mejoran las resistencias a compresión de los morteros de referencia en más de un 48%, y las resistencias a flexión en más de un 67%. De igual forma, los ensayos de lixiviado revelan la completa encapsulación de los iones de Zn y la mitigación en el lixiviado de los iones de Pb. Ambos morteros podrían ser perfectamente validos en actuaciones en las que se necesitase un producto de fraguado rápido, altas resistencias iniciales y compensación de las retracciones con una elevada estabilidad dimensional. En base a esto, el material podría ser utilizado como mortero de reparación en viales y pavimentos que requiriesen altas prestaciones, tales como: soleras industriales, pistas de aterrizaje, aparcamientos, etc. O bien, para la confección de elementos prefabricados sin armaduras estructurales, dada su elevada resistencia a flexión. ABSTRACT This dissertation presents the results of a research on inerting fly ash from urban solid waste and its subsequent encapsulation in mortar matrixes. The inerting of this hazardous toxic waste, as well as its valorization as a by-product has been achieved. In this way, a new "raw material" is available through a simple process and the toxic and hazardous waste is eliminated, and consequently, conservation of alternative natural resources is strengthened. Chemical analysis of the ashes analyzed shows high concentrations of soluble chlorides, Zn and Pb. An inerting process of fly ash with sodium bicarbonate (NaHCO3) has been developed which reduces 99% the content of chlorides and maintains pH at optimal values, so that the concentration of heavy metals in the leachate is minimum, due to its stabilization in the form of insoluble carbonates. Mortars with four different types of cements (CEM-I, CEM-II, CAC and CSA) have been developed by the addition of inertized fly ash in the form of carbonates, in the proportion of 10% in weight of the aggregates used. The samples tested include different proportions in the use of aggregates with different sizes (0/2 and 0/4), and in the cement/aggregate ratio (1/1 and 1/3). Physical/mechanical properties of these mortars have been studied through workability, dimensional stability, carbonation, porosity and mechanic strength tests. Leaching tests of Zn, Pb, Cu and Cd ions are also being performed on monolithic samples of the best behavioral mortars. The content in leachated heavy metal ions is being analyzed through stripping voltammetry determination. Conclusions drawn are that the tested CAC and CSA cement mortars present much better behavior than those of CEM-I and CEM-II cement. The results are especially remarkable for the CAC cement mortars, improving reference mortars compression strengths in more than 48%, and also bending strengths in more than 67%. Leaching tests confirm that the encapsulation of Zn and Pb is achieved and leachate of both ions is mitigated within the mortar matrixes. For the above stated reasons, it might be concluded that mortars made with calcium aluminate cements or calcium sulfoaluminate with the incorporation of treated fly ash, may be perfectly valid for uses in which a fast-curing product, with high initial strength and drying shrinkage compensation with a high dimensional stability is required. Based on this, the material could be used as repair mortar for structures, roads and industrial pavements requiring high performance, such as: industrial floorings, landing tracks, parking lots, etc. Alternatively, it could also be used in the manufacture of prefabricated elements without structural reinforcement, given its high bending strength.

Implantación de un sistema de depósito, devolución y retorno en el mercado retail español

“Quien contamina, paga“, con esta premisa surgió la idea de este Trabajo Fin de Máster, en adelante TFM, cuyo objetivo era identificar medidas alternativas reales para una optimización del proceso actual de gestión de residuos sólidos urbanos ante una sociedad cada vez más superpoblada y con mayores ratios de consumo. Cada español genera anualmente un volumen de 485 Kg de residuos, de los cuales únicamente el 33 % son reciclados y pueden volver a un flujo normal de uso, especialmente preocupante durante los últimos años es el auge de los productos envasados, tanto de bebidas como de alimentos , cuya utilización se ha duplicado en la última década. La motivación de este trabajo Fin de Máster ha sido la de poner de manifiesto que la sostenibilidad con el medioambiente puede ir de la mano de la rentabilidad y del progreso. Durante este TFM se ha estudiado y analizado la viabilidad económica de implantación de un nuevo modelo de depósito, devolución y retorno en el mercado retail español y como con la adopción de este nuevo sistema se pueden lograr beneficios tanto para el propio minorista, como para el medio ambiente con ratios de reciclado superiores al 98%. La preocupación por el medio ambiente empieza a ser una constante entre los consumidores españoles y dicha preocupación comienza a ser influenciadora en las decisiones de compra (productos eco, sostenibilidad…). Nuestra propuesta consiste en dotar a los principales distribuidores del sector retail español de un sistema de depósito, devolución y retorno para envases de bebidas capaz de generar diferenciación, innovación y rentabilidad frente a la competencia. Dicho sistema consiste en pagar un depósito por cada envase de bebida que se adquiera y su correspondiente devolución en la siguiente compra, una vez que se devuelva vacío al establecimiento. Para ello se ha analizado el sector de la distribución en España, especialmente la distribución de bebidas. Se trata de un sector muy competitivo, que presenta varios formatos en función del tamaño del establecimiento (Hipermercados, Supermercados, tiendas tradicionales). Las principales empresas distribuidoras (Carrefour, Mercadona, Alcampo, Eroski, DIA) se encuentran en procesos de cambios estratégicos para lograr atraer a más consumidores hacia sus tiendas, por lo que nuestra propuesta podrá añadir valor a la hora de influenciar en la decisión del lugar de compra. En nuestro caso, nos dirigiremos principalmente a las grandes empresas distribuidoras, Hipermercados de más de 2.500 m2 ,que cuentan con más de 500 puntos de venta y distribución donde existe la posibilidad real de implantar un SDDR. Además se ha realizado un estudio de mercado sobre la influencia de dicho sistema en el consumidor final, donde se ha detectado dos segmentos principales cuya decisión de compra se vería muy influenciada por la implantación de un SDDR, un segmento Sénior, entre 45-54 años, preocupados por el medio ambiente y con poder adquisitivo suficiente como para que el pago del depósito no sea bloqueante, y un segmento Junior, entre 18-24 años, también muy concienciado el medio ambiente, de capacidad económica menor pero qué influye en la decisión de compra de sus progenitores. Para llevar a cabo este plan de negocio será necesario una inversión inicial de 57.000 €, con unas expectativas de recuperación de dicha inversión en el primer año y una TIR del 56%, presentando un VAN de 127.961 € para los 7 años de vida del proyecto. Para dar a conocer a los clientes del Hipermercado los beneficios de utilizar un sistema SDDR, se realizarán campañas de marketing a través de diferentes canales, promociones de apertura, acciones de marketing exteriores y planes de fidelización. La organización e implantación en el Hipermercado será muy sencilla con roles claramente diferenciados, únicamente involucraría a unos 9 recursos definidos y en aproximadamente 3 meses desde el inicio del proyecto ya se podría ofertar dicho servicio a los clientes del Hipermercado. Además se han analizado los principales riesgos a los que se enfrentaría el negocio, ponderándose en una matriz impacto-probabilidad. Se han establecido medidas correctoras en el caso que dicho riesgo aflore. Habrá que tener especialmente precaución con la pérdida de ventas durante el arranque del negocio en el caso que esto ocurra, por lo que se deberá controlar el gasto, fomentar la captación de clientes y mantener un fondo de maniobra lo suficientemente elevado como para absorber dicho riesgo.---ABSTRACT---“Polluters pay”, with this premise this TFM aimed at identifying real alternative measures for optimization of the current process of solid waste management in a crowded society and with greater consumption ratios. Spaniards generates an annual volume of 485 kg of waste; only 33 % are recycled and can return to a normal flow. Specially concern is the increased of packaged product in recent years, mainly drink and food, their use has been duplicated in the last decade. The motivation for this Thesis was to highlight that sustainability, profitability and progress can go together. During this TFM has been studied and analyzed the economic feasibility of implementing a new model of deposit , refund and return in the Spanish retail market and as with the adoption of this new system can achieve benefits for the retailer itself therefore to the environment with ratios above 98% recycled. Concern for the environment is becoming a constant among Spanish consumers , and this concern is becoming influencer in purchasing decisions ( eco, sustainability ... ) . Our proposal is to provide the main distributors of the Spanish retail sector a system of deposit, refund and return for beverage containers capable of generating differentiation, innovation and profitability over the competition. This system is to pay a deposit for each beverage container they purchase and their corresponding return in the next purchase, once they return empty to the establishment. For this we have analyzed the distribution sector in Spain, especially the distribution of beverages. This is a highly competitive industry, which features various formats depending on the size of establishments (hypermarkets, supermarkets, traditional shops). The main distribution companies (Carrefour, Mercadona, Alcampo, Eroski, DIA) are in the process of strategic changes in order to attract more consumers to their stores, so that our approach can add value in influencing the decision of place shopping. In our case, we will go mainly to large distributors, Hypermarkets of over 2,500 m2, which have more than 500 outlets and distribution where there is a real possibility of implementing a SDDR. It has also conducted a market study on the influence of that system on the final consumer, which has detected two main segments whose purchasing decisions would be greatly influenced by the introduction of a SDDR, a Senior segment, 45-54 years concerned about the environment and purchasing power enough that the deposit is not blocking, and a Junior Segment, aged 18-24, also concern with environment, lower economic capacity but what influences the decision purchase of their parents). To carry out this business plan will require an initial investment of 57,000 €, with expectations of recovery of such investment in the first year and an IRR of 56%, with an NPV of € 127,961 for the 7 years of the project . To publicize hypermarket customers the benefits of using a SDDR system, marketing campaigns conducted through different channels, opening promotions, marketing activities and external loyalty schemes. The organization and implementation in the Hypermarket is easy with distinct roles, involve only about 9 resourced and in about 3 months from the start of the project and could offer this service to customers in the hypermarket. We have also analyzed the main risks and established corrective measures to surface that risk . We should take caution with lost sales during startup of the business, such as control spending, customer retention and maintaining enough working capital.