Production of biogas through anaerobic digestion (AD) from the organic fraction of minucipal solid waste (OFMSW) was compared to incineration of the waste. At the moment, almost all of the OFMSW in Singapore is incinerated. Three different scales of biogas plants were compared to incineration: one large-scale biogas plant that can treat half of all OFMSW in Singapore; one medium- scale biogas plant about 15 times smaller than the large one; and one small-scale biogas plant that can treat waste from e.g. a shopping centre or food centre. Two alternatives for utilization of the biogas were also compared, generation of electricity and the use of the biogas in heavy vehicles. The combination of the different scales and the different utilization gives the six different scenarios. By using life cycle assessment (LCA) the different scenarios were compared in terms of global warming potential (GWP), acidification, eutrophication, energy use and land use. The results show that biogas production creates less environmental impact than incineration. The use of the gas as a vehicle fuel creates a bigger decrease of GWP, acidification and eutrophication than when using the gas for electricity generation. The prevention of leakage of biogas during production and upgrading is crucial for the environmental impact on GWP. A leakage of only a few percent of the produced gas will lead to a loss of all the gain in saved GHG-emissions.

No description available.

No description available.

No description available.

The energy carrier hydrogen is expected to solve some energy challenges. Since its oxidation does not emit greenhouse gases (GHGs), its use does not contribute to climate change, provided that it is derived from clean energy sources. Thermochemical water splitting using a Cu-Cl cycle, linked with a nuclear super-critical water cooled reactor (SCWR), which is being considered as a Generation IV nuclear reactor, is a promising option for hydrogen production. In this thesis, a comparative environmental study is reported of the three-, four- and five-step Cu-Cl thermochemical water splitting cycles with various other hydrogen production methods. The investigation uses life cycle assessment (LCA), which is an analytical tool to identify and quantify environmentally critical phases during the life cycle of a system or a product and/or to evaluate and decrease the overall environmental impact of the system or product. The LCA results for the hydrogen production processes indicate that the four-step Cu-Cl cycle has lower environmental impacts than the three- and five-step Cu-Cl cycles due to its lower thermal energy requirement. Parametric studies show that acidification potentials (APs) and global warming potentials (GWPs) for the four-step Cu-Cl cycle can be reduced from 0.0031 to 0.0028 kg SO2-eq and from 0.63 to 0.55 kg CO2-eq, respectively, if the lifetime of the system increases from 10 to 100 years. Moreover, the comparative study shows that the nuclear-based S-I and the four-step Cu-Cl cycles are the most environmentally benign hydrogen production methods in terms of AP and GWP. GWPs of the S-I and the four-step Cu-Cl cycles are 0.412 and 0.559 kg CO2-eq for reference case which has a lifetime of 60 years. Also, the corresponding APs of these cycles are 0.00241 and 0.00284 kg SO2-eq. It is also found that an increase in hydrogen plant efficiency from 0.36 to 0.65 decreases the GWP from 0.902 to 0.412 kg CO2-eq and the AP from 0.00459 to 0.00209 kg SO2-eq for the four-step Cu-Cl cycle. / UOIT

Environmental Diagnosis of Process Plants by Life Cycle TechniquesHaydée A. Yrigoyen GonzálezEl objetivo de la investigación es desarrollar una herramienta que relacione aspectos desimulación, evaluación ambiental y análisis de sensibilidad. Para lo cual se estableció unametodología que consta de cinco niveles: Simulación de proceso, Inventario, evaluación deimpactos ambientales, análisis económico y análisis de sensibilidad.La metodología describe las variables relacionadas con el proceso, así como losimpactos asociados a cada una de sus etapas y la viabilidad económica del proceso, eidentifica las etapas de proceso con el mayor impacto ambiental (mediante el análisis desensibilidad).Para la simulación de procesos se empleó el simulador ASPEN Hysys®. El inventario,la evaluación de impactos y el análisis económico se lleva a cabo en hojas de cálculo de formaautomática.La obtención del inventario de efectos ambientales y la evaluación de loscorrespondientes impactos se realizan siguiendo la metodología de ciclo de vida, por lo que seconsideran las cargas ambientales asociadas a las materias primas, la generación deelectricidad y utilidades. Para obtener el inventario se construyó una base de datos quecontiene la información ambiental asociada a varios procesos industriales que se relacionanindirectamente al proceso bajo estudio. Similarmente, se incluyó una base de datos con losfactores de caracterización de las categorías de impacto más importantes.La validación de la metodología y de la herramienta desarrollada se ha llevado a cabomediante tres procesos industriales: polietileno de baja densidad (LDPE), óxido de etileno (EO)y biodiesel. Para cada proceso se han evaluado diferentes configuraciones para poderdeterminar cual de ellas es la mejor opción desde el punto de vista ambiental y económico.En el caso del LDPE, el cambio de configuración se ha enfocado en el origen de laelectricidad, la cual puede ser proveniente de la Red Nacional Española o de una unidad decogeneración. Los resultados indican que la mejor configuración corresponde al proceso queemplea electricidad proveniente de la unidad de cogeneración, puesto que se obtiene vaporcomo sub-producto y se evitan las emisiones asociadas a la generación de electricidad, lo quese refleja en una importante reducción de los impactos ambientales asociados.En el segundo proceso analizado, referente a la producción de oxido de etileno, se hanevaluado cuatro configuraciones, empleando aire u oxígeno como materia prima y electricidadde la Red Española o produciéndola mediante cogeneración. En relación al origen de laelectricidad, al emplear la cogeneración, el comportamiento ambiental del proceso mejoraconsiderablemente. En cuanto a la importancia de la materia prima empleada, al utilizaroxígeno se obtiene un mejor rendimiento en la etapa de reacción, con lo cual se compensa loscostes asociados a la materia prima con la productividad del proceso.Finalmente, se ha llevado a cabo la evaluación del proceso de producción de biodiesel,se comparó el comportamiento ambiental del proceso empleando un catalizador ácido y uncatalizador básico. En el proceso ácido se generan menores impactos ambientales. De formasimilar, ésta configuración tiene un mejor perfil económico ya que los costes asociados a laproducción son menores y no se requiere ninguna unidad de pretratamiento (necesaria en elproceso alcalino).Mediante la herramienta desarrollada, la información inicial puede modificarse encualquier momento con el fin de obtener los valores correspondientes a nuevas condiciones.Uno de los aspectos más importantes es el que la herramienta se adapta fácilmente con elmínimo de variaciones. Las bases de datos que se incluyen en las hojas de cálculo pueden seractualizadas por el usuario o ajustarse a las necesidades específicas de cada proceso. Todo elanálisis se lleva a cabo de forma automática, una vez introducida la información inicial delproceso e información económica.Environmental Diagnosis of Process Plants by Life Cycle TechniquesHaydée A. Yrigoyen GonzálezThe objective of this work is to develop a tool that integrates simulation, environmentalassessment and sensitivity analysis aspects. To support this tool, a methodology consisting offive levels was established. These are: process simulation, Inventory, environmental impactsassessment, economic analysis and sensitivity analysis.The developed methodology describes the variables related to the process, as well asthe impacts associated to each stages, the economic viability of the process, and the processstages with the highest environmental impact (by means of the sensitivity analysis).ASPEN Hysys® is the chosen software for the simulation of processes. The inventory,impact assessment and the economic analysis are automatically obtained in spreadsheets, bymeans of macros execution.The inventory and the impacts assessment are performed following the Life Cyclemethodology. Therefore, the environmental loads of the raw materials, electricity generation andutilities are considered. In order to generate the inventory, a data base was constructed; itcontains the environmental information associated to industrial processes that are indirectlyrelated to the process under study. Similarly, a data base with the characterization factors of themost important impact categories was included in the tool.The validation of the methodology and the developed tool has been accomplished bytheir application to three industrial processes: low density polyethylene (LDPE), ethylene oxide(EO) and biodiesel production. Different configurations have been evaluated for each process todetermine the best option from the environmental and economic point of view.For the LDPE process, the configuration change has focused in the origin of theelectricity, which can be supplied by the Spanish National Network or a cogeneration unit.Based on our results, the best configuration corresponds to the process employing electricity bycogeneration, since steam is obtained as by-product and the emissions associated to theelectricity generation are eliminated. These facts are reflected in an important reduction of theoverall impacts associated to this process.In the second analyzed process, referring to the production of ethylene oxide, fourconfigurations have been evaluated: using air or oxygen as raw material and electricity from theSpanish Network or produced by cogeneration. Related to the origin of the electricity, usingcogeneration, a better environmental profile is obtained. On the other hand, the oxygen as rawmaterial is better than air due to the best yield of ethylene oxide in the reaction stage. Due tothe better selectivity of the oxygen in the reaction, the costs of O2 as raw material arecompensated by high production.Finally, the process evaluation of the biodiesel production has been carried out. In thiscase, an acid and a basic catalyst were compared. The best configuration corresponds to theprocess using an acid catalyst. In the acid process lower environmental impacts are generated.Furthermore, this configuration has a better economical profile since the costs associated to theproduction are smaller and a pre-treatment unit is not required, as in the alkaline process.The initial information can be modified at any time to obtain the profile associated to thenew conditions by means of the developed tool. Also, the tool can be adapted to any process inan easy way. The included database can be updated or adjusted by the user at any time topersonalize them to the specific necessities of each process. Once the initial information isintroduced, the analysis is executed automatically.The developed tool is able to make the simulation, its environmental diagnosis,economic evaluation and the sensitivity analysis of any industrial process, introducing the initialoperation conditions.

More than ever, the residential building sector is concerned with improving the social, economicand environmental indicators of sustainability. In order to overcome the increasing concern of today'sresource depletion, environmental considerations and to address sustainability indicators, a practicallife cycle method has been proposed to decision making integrating environmental and socioeconomicalaspects to analyse the impact of sustainability within the residential building sector usingtwo practical life cycle methods. One method is the Material and Energy Analysis (MEA) which issuggested as an appropriate tool to provide a systematic picture of the direct and physical flows of theuse of natural resources and the other is the environmental management tool of Life CycleAssessment (LCA) as a complement to evaluate environmental impacts throughout the life cycle of thesystem.Furthermore, the method provides sustainability information that facility an adequate decisionmaking towards sustainable development at macro and micro levels. Sustainability assessment atmacro level is determined by exogenous variables that can influence the development of a country.Meanwhile sustainable at the micro level is made within the limits of the whole building life cycle,starting from the construction, use (operation and maintenance) and finishing with the end-of-lifephase. To illustrate it, a case study has been carried out based on the application to two buildings, onelocated in Barcelona, Spain and one situated in Pamplona, Colombia. Then, the main objective of thisthesis is to propose a practical life cycle method including environmental and socio-economicalaspects to evaluate indicators that explicitly measure the residential building sector's impacts. Thisthesis has also provided initiatives for residential dwellings to reduce environmental impacts and assiststakeholders in improving customer patterns during the dwelling life cycle.The findings of this thesis state that the appropriate combination of building materials,improvement in behaviours and patterns of cultural consumption, and the application of governmentcodes would enhance decision-making in the residential building sector towards sustainability. Thedifference in consumption in Colombia and Spanish dwellings is not only due to the variation in resultsfor bio-climatic differences but also because of the consumption habits in each country. Theimportance of consumption habits of citizens and the need to decouple socio-economic developmentfrom energy consumption are sought for achieving sustainability from a life cycle perspective. There isa crucial necessity to provide satisfaction to basic needs and comfort requirements of population withreasonable and sustainable energy consumption.Therefore, there is no doubt that applying environmental managements tools as Life CycleAssessment (LCA) and Material and Energy Analysis (MEA) to the full building life cycle can be veryimportant for reducing environmental loads and thereby improving sustainability indicators. Then, anyimprovement in building sustainability is oriented generally to building materials, energy use and wastemanagement in all phases of the building life cycle, having always in mind that building has to bexxviiiaccessible from an economical and social part of view. The type of standard dwelling variessubstantially depending on the geographic location where it is built. Climate, technological, cultural,socio-economical differences clearly define the standard of a building in any context and in any region.This leads to important differences in the LCA results and it means that any extrapolation of existingEuropean LCA data to the case of a developing country would imply important errors. However, thefunction is always the same, to provide protection and housing for its habitants. / Hoy en día, el sector residencial busca mejorar los indicadores de sostenibilidad en los aspectossociales, económicos y ambientales. Con el fin de considerar la creciente preocupación delagotamiento de los recursos naturales y buscar reducir las emisiones adversa al medio ambiente, unmétodo practico basado en el ciclo de vida se ha propuesto para la evaluación socio-económica yevaluación del impacto ambiental en sector residencial utilizando dos métodos. El primero es elAnálisis de Materiales y de Energía (AME) que proporciona una visión sistemática de los flujosdirectos e indirectos de la utilización de los recursos naturales y el segundo método es el Análisis delCiclo de Vida (ACV) como complemento para evaluar los impactos ambientales en todo el ciclo devida del sistema.Adicionalmente, el método proporciona información de sostenibilidad permitiendo la adecuadatoma de decisiones hacia el desarrollo sostenible en los niveles macro y micro. Evaluación de laSostenibilidad en el nivel macro está determinado por variables exógenas que influyen en eldesarrollo de un país. Mientras tanto, sostenibilidad en el nivel micro hace referencia dentro de loslímites de todo el ciclo de vida de una vivienda, comenzando por la fase de construcción, uso(operación y mantenimiento) y terminando con la fase final. Para ilustrarlo, un caso de estudio ha sidollevado a cabo en la aplicación de dos edificios, uno situado en Barcelona, España y otro situado enPamplona, Colombia. Por consiguiente, el objetivo principal de esta tesis es proponer un método quetenga en cuenta los aspectos medio-ambientales y socio-económicos que tiendan a mejorar lasostenibilidad y que explícitamente midan los impactos del sector de residencial. Esta tesis también propone iniciativas de mejora en las viviendas residenciales que conlleven a reducir los impactos ambientales y asistir a los agentes involucrados del sector.Las conclusiones de esta tesis soportan que la combinación adecuada de materiales deconstrucción, el buen comportamiento en los patrones de consumo, y la aplicación de códigos y leyes mejoraran los aspectos sostenibles en el sector de la construcción. La diferencia en el consumo en las viviendas de Colombia y en las Españolas no sólo se debe a la variación de las diferencias bioclimáticas,sino también por los hábitos de consumo en cada país. Se puede observar la importancia de los hábitos de consumo de los ciudadanos y la necesidad de disociar el desarrollo socioeconómico del consumo de energía. Existe una necesidad fundamental de dar satisfacción a las necesidades básicas y requerimientos de confort de la población con un consumo energético razonable y sostenible.Por lo tanto, no hay duda de que la aplicación de herramientas medioambientales como el análisis del ciclo de vida (ACV) y análisis de materiales y energía (AME) es muy importante para minimizar el impacto ambiental y buscar mejorar los indicadores de sostenibilidad. Queda implícito entonces que cualquier mejora en la sostenibilidad está orientado generalmente a la selección apropiada de materiales de construcción, el uso eficiente de energía y la correcta gestión de residuos en todas las fases del ciclo de vida del edificio, teniendo siempre en cuenta que el edificio tiene que ser accesible desde una parte económica y social. El tipo de vivienda estándar varía sustancialmente dependiendo de la ubicación geográfica donde se construya. Aspectos como el clima, la tecnología, la cultura y las diferencias socio-económicas definen claramente el nivel de un edificio en cualquier contexto y en cualquier región. Esto da lugar a importantes diferencias en los resultados del ACV y significa que cualquier extrapolación de datos europeos existentes del ACV para el caso de un paísen desarrollo implicaría errores importantes. Sin embargo, la función es siempre la misma,proporcionar protección y vivienda para sus habitantes

Iron chemistry plays an important role in our world. At the nanoscale, iron oxide nanoparticles (nanomagnetite) have many inherent physical or chemical characteristics that drive potential solutions to real-world problems; appropriation of nanomagnetite’s properties as a “scaffold” for chemistry would further enhance its effectiveness in applications. In an effort to make use of nanomagnetite’s physical properties, a new “Sulfide Green Rust” (sGR) has been synthesized from magnetic iron nanoparticles. The material is crystalline, reactive due to high iron(II) content, and dissolves in the aqueous phase. Nanomagnetite’s magnetic properties were also observed to persist after sGR synthesis. X-ray absorption spectroscopy (XAS) confirmed the synthesis of this new FeS2-like material. The crystallinity, composition, and various physical characteristics were examined using a host of techniques including X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), Mössbauer spectroscopy, CRYO-TEM, Raman spectroscopy, and ultraviolet-to-visible (UV-Vis) spectroscopy. To demonstrate its use, the material was then subjected to a test of its reactive potential, namely water remediation of an orange dye contaminant. Iron serves a function at the macroscale as well regarding water treatment, since iron coagulation-filtration is the industry standard for arsenic treatment. Determining a technology’s merit as a solution goes beyond technical concern, however, as environmental and economic aspects also play important roles. Life Cycle Analysis, or LCA, methodology works to holistically compare each of these facets from cradle to grave. To address the current arsenic drinking water requirements at a case setting in Hungary, the LCA technique was applied on two example arsenic removal technologies, both coagulation-filtration and adsorption. 9 out of 10 considered impact categories tended to favour coagulation-filtration in this small municipality study, however realistic variations in water chemistry and product characteristics led to some overlap of their environmental impact. Electricity did not have a large direct impact, regeneration of the adsorption technology was very costly, and adsorption’s hazardous waste was not reduced compared to coagulation-filtration. Coagulation-filtration is also the cheaper of the two technologies; its highest cost is that of waste disposal, while the highest single expense modeled is that of adsorption media cost.

<p>Waste management is something that affects most people. Thewaste amounts are still increasing, but the waste treatment ischanging towards recycling and integrated solutions. In Swedenproducers’responsibility for different products, a taxand bans on deposition of waste at landfills implicates areorganisation of the municipal solid waste management. Plansare made for new incineration plants, which leads to that wastecombustion comes to play a role in the reorganisation of theSwedish energy system as well. The energy system is supposed toadapt to governmental decisions on decommission of nuclearplants and decreased use of fossil fuels.</p><p>Waste from private households consists of hazardous waste,scrap waste, waste electronics and wastes that to a largeextent are generated in the kitchen. The latter type has beenstudied in this thesis, except for newsprint, glass- and metalpackages that by source separation haven’t ended up in thewaste bin. Besides the remaining amount of the above mentionedfractions, the waste consists of food waste, paper, cardboard-and plastic packages and inert material. About 80-90 % of thismixed household waste is combustible, and the major part ofthat is also possible to recycle.</p><p>Several systems analyses of municipalsolid waste managementhave been performed. Deposition at landfill has been comparedto energy recovery, recycling of material (plastic andcardboard) and recycling of nutrients (in food waste).Environmental impact, fuel consumption and costs are calculatedfor the entire lifecycle from the households, until the wasteis treated and the by-products have been taken care of.</p><p>To stop deposition at landfills is the most importantmeasure to take as to decrease the environmental impact fromlandfills, and instead use the waste as a resource, therebysubstituting production from virgin resources (avoidingresource extraction and emissions). The best alternative tolandfilling is incineration, but also material recycling andbiological treatment are possible.</p><p>Recycling of plastic has slightly less environmental impactand energy consumption than incineration. The difference issmall due to that plastic is such a small part of the totalwaste amount, and that just a small part of the collectedamount is recycled. Cardboard recycling is comparable toincineration; there are both advantages and disadvantages.Source separation of food waste may lead to higher transportemissions due to intensified collection, but severalenvironmental advantages are observed if the waste is digestedand the produced biogas substitutes diesel in busses.Composting has no environmental advantages compared toincineration, mainly due to lack of energy recovery. Therecycling options are more expensive than incineration. Theincreased cost must be seen in relation to the environmentalbenefits and decreased energy use. If the work with sourceseparation made by the households is included in the analysis,the welfare costs for source separation and recycling becomesnon-profitable. It is however doubted how much time is consumedand how it should be valuated in monetary terms.</p><p>In systems analyses, several impacts are not measured.Environmental impact has been studied, but not allenvironmental impact. As the parts of the system are underconstant change, the results are not true forever. Recyclingmay not be unambiguously advantageous today, but it can be inthe future.</p><p>Despite the fact that systems analysis has been developedduring 10 years in Sweden, there are still many decisions takenregarding waste management without support from systemsanalysis and use of computer models. The minority of users ispleased with the results achieved, but the systems analysis isfar from easy to use. The adaptation of tools and models to thedemands from the potential users should consider thatorganisations of different sizes have shifting demands andneeds.</p><p>The application areas for systems analysis and models arestrategic planning, decisions about larger investments andeducation in universities and within organisations. Systemsanalysis and models may be used in pre-planning procedures. Apotential is a more general application (Technology Assessment)in predominantly waste- and biofuel based energy processes, butalso for assessment of new technical components in a systemsperspective. The methodology and systems approach developedwithin the systems analysis has here been transformed to anassessment of environmental, economic and technical prestandaof technical systems in a broad sense.</p>

Att ställa miljökrav inom leverantörskedjorna har blivit allt vanligare i takt med ökat miljöarbete. Det är dock bristfälligt dokumenterat hur väl eventuella miljökrav uppfylls kedjan igenom. För att organisera miljöarbetet har strategier uppkommit vilka tar hänsyn till kedjans miljöpåverkan, såsom Green Supply Chain Management (GSCM). Genom en fallstudie kartlades vilka miljökrav som ställdes, om kraven var konsekventa längs leverantörskedjan och hur kraven kunde relateras till företagens övriga miljöarbete. Fallstudien hade sin utgångspunkt i Liljeholmens Stearinfabriks AB med fokus på värmeljuskoppens leverantörskedja. Genom en semistrukturerad intervju har företagen inom kedjan svarat på frågor kring bl.a. miljökrav. Dessutom har en LCA gjorts på värmeljuskoppen för att se huruvida miljökraven var adekvata med tanke på produktens miljöpåverkan. Resultatet visade att företagen ställde miljörelaterade krav. Dessa krav berörde främst leverantörens allmänna miljöarbete snarare än själva produkten. Typen av ställda krav var ej konsekvent med företagens miljöarbete. LCAn visade på att produktens största miljöpåverkan härrör från aluminiumet. Miljökraven borde således inriktas på större andel återvunnet material.