Ghana, a West Africa country, is deeply burdened by poverty, and relies on the production of gold for economic sustainability. The gold mining companies in the country have international origins and receive most of their requirements from international sources. The extraction of gold from the crushed ore requires sodium cyanide as a lixiviant, which is imported into Ghana from other countries in wooden intermediate bulk containers (IBC) for further distribution to the mines. A life cycle assessment was completed to determine the burden that this packaging, which includes the wooden container and polyethylene and polypropylene liners, places on the environment in Ghana when disposed of. It was found that the life cycle of the incinerated IBC impacted on the Ghanaian environment the most, due to the incineration and the transportation of the IBC. The International Organization for Standardization 14040 management standard was used as a methodological framework for the assessment. / Environmental Science / M.Sc. (Environmental Science)

Die vorliegende Ausgabe beschäftigt sich mit den Herausforderungen der ökologischen Leistungsmessung durch das Instrument der Ökobilanz. Der Fokus wird insbesondere auf Unsicherheiten gelegt. In einer einführenden Betrachtung werden Problemfelder von Ökobilanzstudien erläutert, die in den verschiedenen Phasen der Ökobilanz auftreten. Die weiteren Ausführungen konzentrieren sich auf den Bereich der Unsicherheiten. Nach einer Definition werden die Auswirkungen der Probleme systematisiert und anschließend praktische Möglichkeiten zum Umgang mit diesen erarbeitet. Eine besondere Rolle spielen dabei Datenunsicherheiten, da Ökobilanzstudien als sehr datenintensive Verfahren der Lebenszyklusanalyse bekannt sind. Insgesamt 17 Forschungsfragen, die sich aus den theoretischen Betrachtungen ableiten, wurden anhand einer Literaturstichprobe überprüft. Diese Literaturstichprobe wurde mit dem Verfahren der computergestützten Inhaltsanalyse auf die Forschungsfragen hin untersucht, bei der insgesamt 2.000 Textstellen kodiert worden sind. Bei dieser Analyse werden zunächst allgemeine, definitorische Grundcharakteristika wie die Definition der funktionellen Einheit oder die Angabe des Allokationsverfahrens überprüft. Die tiefergreifende Untersuchung der Studien betrachtet vor allem das generelle Erkennen von Unsicherheiten im Verlauf einer Ökobilanzstudie und den Einsatz von Verfahren, um den Einfluss der Unsicherheiten auf das Ökobilanzergebnis zu verdeutlichen. Dabei stellt sich heraus, dass in weniger als 50 Prozent der Studien eine Aussage kodierbar war, die auf das Erkennen der Unsicherheiten schließen lässt. Dennoch wurden in 37 Prozent der analysierten Studien Verfahren eingesetzt, die in der Lage sind, den Einfluss von Unsicherheiten auf die Ökobilanzergebnisse zu verdeutlichen und somit den Entscheider vor Fehlentscheidungen zu bewahren.

Thesis (MScEng)--Stellenbosch University, 2012 / ENGLISH ABSTRACT: Through many years of research, a number of production schemes have been developed for converting lignocellulosic biomass into transport fuels. These technologies have been assessed through a number of techno-economic studies for application in a particular context in terms of the technical and economic feasibility. However, previous studies using these methods have tended to lack vigour in various aspects. Either the energy efficiency of the processes were not maximised through adequate heat integration, or a competing technology which existed was not considered. From an economic perspective, the financial models would often lack the vigour to account for the risk and uncertainty that is inherent in the market prices of the commodities. This phenomenon is especially relevant for the biofuel industry that faces the full fledge of uncertainties experienced by the agricultural sector and the energy sector. Furthermore, from an environmental perspective, the techno-economic studies had often ignored the environmental impacts that are associated with biofuel production. Thus, a comparative study could have favoured an option due to its economic feasibility, while it could have had serious environmental consequences. The aim of this study was to address these issues in a South African context, where biofuels could be produced from sugarcane bagasse. The first step would be to modify an existing simulation model for a bioethanol scenario that operates with a Separate Hydrolysis and Fermentation (SHF process) configuration into a second processing scenario that operates with a Simultaneous Saccharification and Fermentation (SSF process) configuration using reliable experimental data. The second step was to ensure that the maximum energy efficiency of each scenario was realised by carrying out pinch point analysis as a heat integration step. In contrast to these biological models is the thermochemical model that converts bagasse to gasoline and diesel via gasification, Fischer-Tropsch synthesis and refining (GFT process). While there were no significant advances in technology concerning this type of process, the energy efficiency was to be maximised with pinch point analysis. The GFT process obtained the highest energy efficiency of 50.6%. Without the affects of pinch point technology, the efficiency dropped to 46%, which thus emphasises the importance of heat integration. The SSF had an efficiency of 42.8%, which was superior to that of the SHF at 39.3%. This resulted from a higher conversion of biomass to ethanol in the SSF scenario. Comparing the SHF model to an identical model found in literature that did not have pinch point retrofits, this study showed lower efficiency. This arose because the previous study did not account for the energy demands of the cold utility systems such as the cooling tower operation, which has been shown in this study to account for 40% of the electrical energy needs. The economic viability of all three processes was assessed with Monte Carlo Simulations to account for the risks that the fluctuations in commodity prices and financial indices pose. This was accomplished by projecting the fluctuations of these parameters from samples of a historical database that has been transformed into a probability distribution function. The consequences were measured in terms of the Net Present Value (NPV) and Internal Rate of Return (IRR) for a large number of simulations. The results of these variables were aggregated and were then assessed by testing the probability that the NPV<0, and that the IRR recedes below the interest rate of 12.64%. The investment was thus deemed unfeasible if these probabilities were greater than 20%. Both biological models were deemed profitable in terms of this standard. The probabilities were 13% for the SSF and 14% for the SHF. The GFT process however was deemed completely unfeasible because the probability that the NPV<0 was 78%. Given that the GFT process had the highest energy efficiency, this result arises mainly because the capital investment of 140,000USD/MWHHV of biomass energy input is to enormous for any payback to be expected. The environmental footprint of each process was measured using Life Cycle Assessments (LCAs). LCAs are a scientifically intricate way of quantifying and qualifying the effects of a product or process within a specified boundary. The impacts are assessed on a range of environmental issues, such as Global Warming, Acidification, Eutrophication and Human toxicity. Furthermore, if the project under concern has multiple output products, then the impacts are distributed between the output products in proportion to the revenue that each generates. The impacts were either relative to the flow of feedstock, which was 600MW of bagasse, or to the functional unit, which was the amount of fuel required to power a standard vehicle for a distance of 1 kilometre. In either case, the GFT scenario was the least burdening on the environmental. This was expected because the GFT process had the highest energy efficiency and the process itself lacked the use of processing chemicals. Relative to the feedstock flow, the SSF was the most environmentally burdening scenario due to the intensive use of processing chemicals. Relative to the functional unit, the SHF was the most severe due to its low energy efficiency. Thus, the following conclusions were drawn from the study:  The GFT is the most energy and environmentally efficient process, but it showed no sign of economic feasibility. iv  There is no significant difference in the economic and environmental evaluation of the SSF and SHF process, even though the SSF is considered to be a newer and more efficient process. The major cause of this is because the setup of the SSF model was not optimised. / AFRIKAANSE OPSOMMING: Deur baie jare van navorsing is ‘n aantal produksie-skemas vir die omskakeling van lignosellulose biomassa na vloeibarebrandstof ontwikkel. Hierdie tegnologië is geassesseer ten opsigte van die tegniese en ekonomiese haalbaarheid deur middel van tegno-ekonomiese studies in bepaalde tekste. Tog het hierdie vorige studies besliste beperkings gehad. Of die energie-doeltreffendheid van die proses is nie gemaksimeer deur voldoende hitte-integrasie nie, of 'n mededingende tegnologie wat bestaan is nie oorweeg nie. Vanuit 'n ekonomiese perspektief, was die finansiële modelle dikwels nie die omvattend genoeg om rekening te hou met die risiko en onsekerheid wat inherent is in die markpryse van die kommoditeite nie. Hierdie verskynsel is veral relevant vir die biobrandstof bedryf wat die volle omvang van onsekerhede ervaar waaraan die landbousektor en die energiesektoronderhewig is. Verder het die tegno-ekonomiese studies dikwels die omgewingsimpakte wat verband hou met biobrandstofproduksie geïgnoreer. Dus kon ‘n opsie deur die ekonomiese haalbaarheid bevoordeel word, ten spyte van die ernstige omgewingsimpakte wat dit kon inhou. Die doel van hierdie studie was om hierdie kwessies aan te spreek in 'n Suid-Afrikaanse konteks, waar biobrandstof uit suikerriet bagasse geproduseer kan word. Die eerste stap was om 'n bestaande simulasiemodel vir 'n bio-scenario wat met Afsonderlike Hidroliese en Fermentasie (SHF proses) stappe werk, te modifiseer vir 'n tweede verwerking scenario wat met 'n gelyktydige Versuikering en Fermentasie (SSF proses) konfigurasie werk. Die verandering is gedoen deur die gebruik van betroubare eksperimentele data. Die tweede stap was om te verseker dat elke scenario die maksimum energie-doeltreffendheid het, deur 'n hitte-integrasie stap, wat gebruik maak van “pinch-point” analise. In teenstelling met hierdie biologiese modelle, is daar die thermochemiese roete waar petrol en diesel van bagasse vervaardig word via vergassing, Fischer-Tropsch-sintese en rafinering (GFT proses). Daar was geen betekenisvolle vooruitgang in tegnologie vir hierdie proses nie, maar die energie-doeltreffendheid is gemaksimeer word deur energie-integrasie. Die GFT proses toon die hoogste energie-doeltreffendheid van 50,6%. Sonder die invloed van energie-integrasie het die doeltreffendheid gedaal tot 46%, wat dus die belangrikheid van hitte-integrasie beklemtoon. Die SSF het 'n effektiwiteit van 42,8% gehad, wat beter was as dié 39,3% van die SHF opsie. Hierdie hoër effektiwiteit wasas gevolg van die hoër omskakeling van biomassa na etanol in die SSF scenario. Die energie doeltreffendheid vir die SHF-model was laer as met 'n identiese model (sonder energie-integrasie) wat in die literatuur gevind wat is. Dit het ontstaan omdat die vorige studie nie 'n volledig voorsiening gemaak het met die energie-eise van die verkillingstelselsnie, wat tot 40% van die elektriese energie behoeftes kan uitmaak. Die ekonomiese lewensvatbaarheid van al drie prosesse is bepaal met Monte Carlo simulasies om die risiko's wat die fluktuasies in kommoditeitspryse en finansiële indekse inhou, in berekening te bring. Hierdie is bereik deur die projeksie van die fluktuasies van hierdie parameters aan die hand van 'n historiese databasis wat omskep is in 'n waarskynlikheid verspreiding funksie. Die gevolge is gemeet in terme van die netto huidige waarde (NHW) en Interne Opbrengskoers (IOK) vir 'n groot aantal simulasies. Die resultate van hierdie veranderlikes is saamgevoeg en daarna, deur die toets van die waarskynlikheid dat die NPV <0, en dat die IRR laer as die rentekoers van 12,64% daal, beoordeel. Die belegging is dus nie realiseerbaar geag as die waarskynlikhede meer as 20% was nie. Beide biologieseprosesse kan as winsgewend beskou word in terme van bostaande norme. Die waarskynlikhede was 13% vir die SSF en 14% vir die SHF. Aangesien die NHW van die GFT-proses onder 0 met ‘n waarskynlikheid van 78% is, is die opsie as nie-winsgewend beskou. Gegewe dat die GFT-proses die hoogste energie-doeltreffendheid het, is die resultaat hoofsaaklik omdat die kapitale belegging van 140,000 USD / MWHHV-biomassa energie-inset te groot is, om enige terugbetaling te verwag. Die omgewingsvoetspoor van elke proses is bepaal deur die gebruik van Lewens Siklus Analises (“Life Cycle Assessments”) (LCAS). LCAS is 'n wetenskaplike metodeom die effek van ‘n produk of proses binne bepaalde grense beide kwalitatief en kwantitatief te bepaal. Die impakte word beoordeel vir 'n verskeidenheid van omgewingskwessies, soos aardverwarming, versuring, eutrofikasie en menslike toksisiteit. Voorts, indien die projek onder die saak verskeie afvoer produkte het, word die impakte tussen die afvoer produkte verdeel, in verhouding tot die inkomste wat elkeen genereer. Die impak was met of relatief tot die vloei van roumateriaal (600MW van bagasse), of tot die funksionele eenheid, wat die hoeveelheid van brandstof is om 'n standaard voertuig aan te dryf oor 'n afstand van 1 kilometer. In al die gevalle het die GFT scenario die laagste belading op die omgewing geplaas. Hierdie is te verwagte omdat die GFT proses die hoogste energie-doeltreffendheid het en die proses self nie enige addisionele chemikalieë vereis nie. Relatief tot die roumateriaal vloei, het die SSF die grootse belading op die omgewing geplaas as gevolg van die intensiewe gebruik van verwerkte chemikalieë. Relatief tot die funksionele eenheid, was die SHF die swakste as gevolg van sy lae energie-doeltreffendheid.

Thesis (PhD(Agric))--Stellenbosch University, 2012. / ENGLISH ABSTRACT: The energy paradigm shift from fossil fuels to renewable energy sources is driven, among others, by a growing sustainability awareness, necessitating more sophisticated measurements in terms of a wider range of criteria. Technical efficiency, financial profitability, environmental friendliness and social acceptance are some of the factors determining the sustainability of renewable energy systems. The resulting complexity and conflicting decision criteria, however, constitute major barriers to processing the information and decision-making based on the information. Seeking to implement local bioenergy systems, policymakers of the Cape Winelands District Municipality (CWDM), South Africa, are confronted with such a problem. Following a case study approach, this study illustrates how life-cycle assessment (LCA), multi-period budgeting (MPB) and geographic information systems (GIS) can aid the decision-making process by providing financial-economic, socio-economic and environmental friendliness performance data in a structured and transparent manner, allowing for a comparison of the magnitude of each considered criterion along the life-cycle. However, as the environmental impacts cannot readily be expressed in monetary terms on a cardinal scale, these considerations are given less attention or are omitted completely in a market economy. By measuring the various considerations on an ordinal scale and by attaching weights to them using the multi-criteria decision analysis (MCDA) approach, this study, illustrates how to internalise externalities as typical market failures, aiding policymakers of the CWDM to choose the most sustainable bioenergy system. Following the LCA approach, 37 lignocellulosic bioenergy systems, encompassing different combinations of type of harvesting and primary transport, type of pretreatment (comminution, drying, and fast pyrolysis) and location thereof (roadside or landing of the central conversion plant), type of secondary transport from the roadside to the central conversion plant, and type of biomass upgrading and conversion into electricity, were assessed against five financial-economic viability criteria, three socio-economic potential criteria and five environmental impact criteria. The quantitative performance data were then, as part of the MCDA process, translated into a standardised ‘common language’ of relative performance. An expert group attached weights to the considered criteria using the analytical hierarchy process (AHP). The ‘financial-economic viability’ main criterion received a weight of almost 60%, ‘socio-economic potential’, nearly 25% and ‘lowest environmental impact’, the remainder of around 16%. Taking the prerequisite of financial-economic viability into consideration, the preferred option across all areas of the CWDM (despite various levels of productivity) comprises a feller-buncher for harvesting, a forwarder for primary transportation, mobile comminution at the roadside, secondary transport in truck-container-trailer combinations and an integrated gasification system for the conversion into electricity. / AFRIKAANSE OPSOMMING: Die energie paradigma verandering van fossielbrandstowwe na hernubare energiebronne word gedryf deur ‘n groeiende klem op volhoubaarheid, wat ook meer gesofistikeerde meting in terme van ‘n wyer verskeidenheid maatstawwe vereis. Tegniese doeltreffendheid, finansiële winsgewendheid, omgewingsvriendelikheid en sosiale aanvaarbaarheid is sommige van die faktore wat die volhoubaarheid van hernubare energie stelsels bepaal. Die verskeidenheid oorwegings bring egter kompleksiteit en konflik mee by die verwerking van inligting en die besluitneming wat daarop berus. Beleidmakers van die Kaapse Wynland Distriksmunisipaliteit wat ten doel het om plaaslik bio-energie stelsels te implementeer, word met hierdie probleem gekonfronteer. Hierdie ondersoek illustreer aan die hand van ‘n gevallestudie benadering hoe lewensiklus analise, multiperiode begroting en geografiese inligtingstelsels besluitneming kan ondersteun deur die voorsiening van finansieel-ekonomiese, sosio-ekonomiese (indiensneming) en omgewingsvriendelikheid prestasie data op ‘n gestruktureerde en deursigtige wyse. Dit maak die vergelyking van die waardes van al die kriteria by elke fase van die lewensiklus moontlik. Aangesien die omgewingseffekte nie geredelik in monetêre terme op ‘n kardinale skaal gemeet kan word nie, kry hulle binne die markekonomie minder aandag of word selfs buite rekening gelaat. Deur hierdie verskeidenheid kriteria op ‘n ordinale skaal te meet en gewigte met behulp van multikriteria besluitneming aan hulle toe te ken, toon hierdie ondersoek hoe om eksternaliteite as tipiese markmislukkings te internaliseer om beleidmakers van die Kaapse Wynland Distriksmunisipaliteit in staat te stel om die mees volhoubare bio-energie stelsel te kies. Met behulp van lewensiklus analise is 37 lignosellulose bio-energie stelsels geïdentifiseer as verskillende kombinasies van oes van die bome, primêre vervoer van houtstompe, vooraf verwerking (verspaandering, droging, vinnige pirolise), die ligging van hierdie aktiwiteite (langs ‘n plantasie of by ‘n sentrale omsettingsaanleg), tipe sekondêre vervoer van houtspaanders vanaf die plantasie na die sentrale omsettingsaanleg en tipe biomassa opgradering en omsetting van die houtspaanders na elektrisiteit. Die verskillende stelsels is gemeet aan die hand van vyf finansieel-ekonomiese kriteria, drie indiensneming potensiaal kriteria en vyf omgewingsimpak kriteria. Die kwantitatiewe metings is deur middel van multikriteria besluitneming omgeskakel na ’n gestandaardiseerde “gemeenskaplike taal” van relatiewe prestasie. Lede van ‘n ekspertgroep het gewigte is aan die onderskeie kriteria met behulp van die analitiese hierargie proses toegeken. Aan die finansieel-ekonomiese lewensvatbaarheid hoof kriterium is ‘n gewig van by die 60% toegeken, aan die indiensnemingspotensiaal bykans 25% en aan omgewingsvriendelikheid sowat 16%. Die voorkeur kombinasie vir al die areas van die Kaapse Wynland Distriksmunisipaliteit sluit in ‘n saag-bondelaar vir die oesproses, ‘n plantasie-vragmotor vir primêre vervoer, mobiele verspaandering langs die plantasie, ‘n vragmotor-skeepshouer-treiler kombinasies vir die sekondêre vervoer van houtspaanders en ‘n geïntegreerde vergassingstelsel vir die omsetting van houtspaanders na elektrisiteit.

<p>Прeдмeт истрaживaњa je кoришћeњe oтпaдa у Рeгиoну Сeвeрo- Истoчнe БиХ зa пoтрeбe грaђeвинaрствa. Циљ истраживања је био рaзвoj мoдeлa зa eфeктивнo упрaвљaњe oтпaдoм сa eкoнoмскoг и eкoлoшкoг aспeктa.<br />Прикaзaни рeзултaти тeoриjских и aпликaтивних истрaживaњa укaзуjу дa се и у услoвимa ограничења eкoнoмскe, тeхнoлoшкe, тржишнe и инфрaструктурнe прирoдe, oствaруjе пoзитивни утицaj система менаџмента отпадом нa нивo oдрживости и нивo рaзвoja пoсмaтрaнoг рeгиoнa.</p> / <p>Predmet istraživanja je korišćenje otpada u Regionu Severo- Istočne BiH za potrebe građevinarstva. Cilj istraživanja je bio razvoj modela za efektivno upravljanje otpadom sa ekonomskog i ekološkog aspekta.<br />Prikazani rezultati teorijskih i aplikativnih istraživanja ukazuju da se i u uslovima ograničenja ekonomske, tehnološke, tržišne i infrastrukturne prirode, ostvaruje pozitivni uticaj sistema menadžmenta otpadom na nivo održivosti i nivo razvoja posmatranog regiona.</p> / <p><strong>The research subject is related to using of waste in region of northeast<br />Bosnia and Hercegovina for purpose of construction. Research<br />and goal was development of model for effective waste management<br />from economic and ecological aspect.<br />Presented theoretical and empirical research results pointed that even<br />condition of constraints of economic, technological, market, and<br />infrastructure nature, using proposed new model are possible to<br />achieve positive impacts of waste management system on level of<br />sustainability and level of development of analyses region.</strong></p>

Cette thèse porte sur l’étude des impacts environnementaux de systèmes de production de bovins. Le premier objectif était d’analyser et de comparer les impacts environnementaux de systèmes de production de viande et de lait par analyse de cycle de vie (ACV) attributionnelle. Les effets de pratiques d’atténuation de ces impacts ont été évalués pour les systèmes de production de viande. Le second objectif était un développement méthodologique afin d’explorer les conséquences possibles d’une préférence accrue pour un lait produit à base d’herbe, par ACV conséquentielle. Dans un système de production de viande par le troupeau allaitant, le méthane entérique a été le principal contributeur à l’impact changement climatique, et la production de l’herbe a été la principale contributrice aux autres impacts (demande énergétique cumulée, eutrophisation, acidification, occupation du sol). L’atelier naisseur (vaches allaitantes et leurs veaux, génisses) a contribué de manière majeure aux impacts du système allaitant dans son ensemble. La pratique d’atténuation la plus efficace pour le système a été la diminution de l’âge au vêlage de 3 à 2 ans. L’utilisation de lipides riches en acides gras oméga-3 dans le régime a très peu affecté les impacts du système. L’application simultanée de plusieurs pratiques d’atténuation compatibles entre elles réduit sensiblement les impacts. L’application de pratiques telles que la réduction du gaspillage d’herbe, l’engraissement des génisses non utilisées pour le renouvellement et la diminution de l’âge au vêlage réduisent l’occupation du sol. Un usage alternatif des terres libérées tel que la plantation de forêt pour séquestrer du carbone dans la biomasse semble prometteur. L’étude de systèmes de production de lait a été centrée sur les comparaisons de systèmes à base d’herbe ou d’ensilage de maïs, d’une race spécialisée (Holstein) ou mixte (Normande) et sur l’effet du niveau de production laitière par ACV attributionnelle. Quelle que soit la méthode d’attribution des impacts aux co-produits, les impacts par kg de lait ont été plus faibles pour les systèmes à base d’ensilage de maïs et pour les Holstein, sauf pour l’eutrophisation. L’accroissement de la production de lait par vache grâce à une consommation d’énergie accrue et au vêlage à 2 ans a permis de réduire les impacts du lait et de son co-produit viande. Les conséquences de la conversion d’une exploitation laitière utilisant beaucoup de maïs ensilage vers une exploitation utilisant de l’herbe comme unique source de fourrage pour répondre à une demande de lait produit à base d’herbe en France ont été évaluées par ACV conséquentielle. Cette conversion entraîne des changements notables de l’utilisation des sols en dehors de l’exploitation, et donc un fort accroissement des impacts du système dans son ensemble et du lait produit. / This thesis addresses the environmental impacts of cattle production systems. The first objective of this thesis was to analyse and compare the environmental impacts of suckler-beef and dairy production systems using attributional life cycle assessment (ALCA). Subsequently, the effects of mitigation practices for suckler-beef production systems were assessed. The second objective addressed methodology development by exploring possible consequences due to an increase in preference for grass-based milk using consequential LCA (CLCA).For a suckler-beef production system, enteric methane fermentation was the main contributor to the climate change impact, and grassland production contributed most to other impacts (cumulative energy demand, eutrophication, acidification and land occupation). The suckler cow-calf herd substantially contributed to the impacts of the suckler-beef system. The most effective mitigation practice for the suckler-beef production system was decreasing calving age from 3 to 2 years. The use of lipids rich in omega-3 fatty acids in ruminant diets did not substantially affect the impacts of the suckler-beef production system. Simultaneous application of several compatible practices can substantially mitigate the impacts of the suckler-beef production system. The application of certain practices (e.g. reducing ungrazed grass losses, fattening heifers not used for replacement and reducing calving age) reduced land occupation. Alternative uses for the “released land”, e.g. the introduction of forest to sequester C into biomass, seems promising. For dairy production systems, the assessment focused on a grass-based vs. maize-silage-based system, dual-purpose breed (Normande) vs. specialised breed (Holstein) and the effect of increasing milk yield per cow, using the ALCA approach. Independent of co-product handling methods, the impacts per kg of milk were lower with the maize-silage-based system and with Holstein cows (except for eutrophication). Increasing milk yield per cow by increasing feed energy intake and applying more intensive management (first calving at 2 years) decreased the impacts of milk and its beef co-product. The consequences of converting a maize-silage-based to a grass-based dairy farm in France to meet the increased domestic preference for grass-based milk were assessed using the CLCA approach. This farm conversion caused land-use change outside the dairy farm and thus substantially increased the impacts of the whole production system and the milk it produced.

Au cours de cette thèse, les prévisions de la méthodologie d’Analyse de Cycle de Vie (ACV) sont améliorées, via l’exergie, pour l’analyse et l’éco-conception des procédés. Nous mettons l’accent sur le potentiel de l’analyse exergétique et de la Consommation d’Exergie Cumulée (CExC) dans l’évaluation du critère d’épuisement, de productivité et de recyclabilité des ressources naturelles. Dans ce cadre, les transferts de pollutions et les impacts environnementaux d’un système de traitement des eaux résiduaires (STEP) ont été analysés en relation avec l’exergie consommée (CExC) et de l’exergie détruite (étude a priori). L’étude montre que la décision est différente lorsque l’indicateur d’épuisement des ressources naturelles est basé sur la méthode CExC de celle basée sur la méthode CML. L’amélioration de l’éco-efficacité d’une STEP implique un recyclage des boues en agriculture. La stabilisation des boues par digestion anaérobie réduit le volume des boues et ainsi l’impact du transport en comparaison avec la stabilisation à la chaux. Toutefois, elle réduit le potentiel fertilisant des boues, d’une part, et augmente la consommation d’énergie et l’impact du réchauffement climatique à cause du traitement des retours en tête d’autre part. Bien que la valorisation du biogaz en cogénération réduise la dépendance énergétique de la STEP et améliore son éco-efficacité globale en comparaison avec le chaulage, elle n’offre pas la possibilité à un séchage des boues. Le séchage des boues constitue l’une des recommandations des agriculteurs, bien qu’il n’améliore pas le l’éco-efficacité globale de la STEP, en augmentant l’épuisement et l’exergie détruite des ressources brutes et du biogaz / The focus of the work has been to improve the predictions of Life Cycle Assessment (LCA) via exergy for processes analysis and eco-design. The potential of the exergetic analysis and Cumulative Exergy Consumption (CExC) in estimating the criterion of depletion, productivity and recyclability of natural resources has been investigated. In this context, the transfer of pollutants and the environmental impacts of a wastewater treatment system (WWTP) have been analyzed in relation with the consumed exergy (CExC) and the destroyed exergy. The study shows that decision is different if the indicator of depletion of natural resources is based on the method of CExC or on the CML method. The improvement of the overall eco-efficiency of a WWTP involves a recycling of sludge in agriculture. Stabilization of sludge by anaerobic digestion reduces the volume of sludge and consequently the impact of transport in comparison with the stabilization with lime. However, on one hand, it reduces the fertilizer potential of sludge. On the other hand it increases energy consumption and the impact of the global warming because of the treatment of digested sludge supernatant recycled to the WWTP. Although the recovery of biogas by cogeneration reduces the energy dependency of the WWTP and improves its overall eco-efficiency in comparison with the liming scenario, it does not provide the possibility for sludge drying. Drying the sludge is one of the recommendations of farmers, although it does not improve the overall eco-effectiveness of the WWTP, and increases the depletion and the destroyed exergy of raw resources and biogas

This thesis answers how a circular economy-based offering can be designed for increased value creation and decreased environmental impact, compared to a current offering. The study concerns a case company and their current offering of a fire safety solution, namely a 6 kg powder fire extinguisher. The concept Product-Service Systems is used as a base for the research and a foundation of the result.Throughout the study, the method Life Cycle Assessment (LCA) is used as a tool to evaluate and compare the current and the suggested solution in the sense of environmental sustainability amongst different impact categories. It provides a holistic perspective within the study which has been proven by theory to be an important factor when providing a circular economy-based offering. Another important factor is customising the offering to the specific case. This is attended to through an investigation of the company characteristics, the current offering and provider and customer values to find opportunities for the suggested solution. Opportunities found was e.g. a demand for an environmentally sustainable solution and existing infrastructure which can create valuein the future.The process includes, apart from the LCAs, interviews, a workshop at the case company and a survey addressed to end users. The use of visualisation tools such as actors map and Product-Service Blueprint benefits the understanding of both current and suggested solution and provides insights, evaluation and possible improvements. A cost calculation is made to evaluate if the solution is financially making business sense to the provider. Through this thesis, a circular economy-based solution which designs out waste is found. It is proven through the study and LCAs that this solution decreases the investigated environmental impact categories compared to the current existing solution. The suggested solution is based on a refilling process for circulating material which is established through the thesis to be theoretically feasible, hence needs consideration in order to be implementable in reality and make business sense to the provider. / Den här studien svarar på hur ett erbjudande baserat på cirkulär ekonomi kan designas för att öka värdeskapande och sänka miljöpåverkan i förhållande till ett existerande erbjudande. Studien baseras på ett företagsfall och deras nuvarande brandsäkerhetslösning, nämligen en 6 kg pulversläckare. I studien involveras teori om Product-Service Systems som en bas för forskningen och en grund för resultatet. Genom studien har metoden Livscykelanalys (LCA) använts som ett verktyg för att utvärdera och jämföra den nuvarande lösningen med den föreslagna i ett miljömässigt sammanhang och med flera olika påverkanskategorier. Detta skapar ett holistiskt perspektiv, vilket teorin visar är en viktig faktor under utvecklingen av ett erbjudande baserat på cirkulär ekonomi. En annan viktig faktor är att anpassa designen av erbjudandet till ett specifikt fall. Detta uppmärksammas genom en undersökning av företagets egenskaper, det nuvarande erbjudandet och leverantörs- och kundvärde för att finna möjligheter till en föreslagen lösning. Sådana möjligheter var till exempel en efterfrågan på miljömässigt hållbara lösningar och en existerande infrastruktur som kan gagna företagets värdeskapande i framtiden. Processen inkluderar, förutom LCA, intervjuer, en workshop, och en kundundersökning adresserad till slutanvändare. Användandet av visualiseringsverktyg, sådana som aktörskarta och Product-Service Blueprint, gynnar förståelsen för både den nuvarande och den föreslagna lösningen och skapar insikter kring utvärdering och möjliga förbättringar. En kostnadskalkyl görs för att utvärdera om lösningen är finansiellt bra för företaget. Genom denna avhandling upptäcks en cirkulär ekonomi-baserad lösning. Studien visar att denna lösning minskar miljöpåverkan för de valda påverkanskategorierna jämfört med den nuvarande lösningen. Den föreslagna lösningen är baserad på att återfylla brandsläckare och därigenom cirkulera material vilket är teoretiskt genomförbart. Dock behövs ytterligare övervägande för att lösningen ska vara implementerbar och för förföretaget realiserbart.

The cradle to cradle (C2C) is a sustainable business strategy that mimics the natural recycling cycle and waste is reused, the question of when and how to apply the C2C concept successfully in business is still controversial. This thesis takes Huawei, the leading enterprise in the mobile communication industry, as an example, and to investigate the challenges for Chinese mobile communication companies in implementing an effective C2C strategy to achieve a sustainable development. This study used the semi-structured interviews in the qualitative data collection method to interview both Huawei and China Telecommunications’ managers. Data analysis shows that for the electronics industry with low recycling rate and high pollution, Huawei still faces many challenges in adopting the C2C strategy，which includes alloy recycling, recycling of electronic products in consumers' hands, disassembly problems, and recycling of electronic products by value, Another challenge is the mismatch between C2C evaluation mechanism and China's mobile communications industry. Only fully considered cradle to cradle, cradle to Grave, and Life cycle, the sustainable mode of the mobile communications industry would be reached.

A Análise de Ciclo de Vida (ACV) tem se mostrado uma importante ferramenta de avaliação ambiental, devido à seu enfoque “sobre função", que permite considerar o desempenho ambiental de produtos, procedimento cada vez mais requerido por diversos atores sociais. Para que a ACV possa ser utilizada de modo amplo e confiável, faz-se necessário que se desenvolvam bases de dados regionalizadas, contendo Inventários de Ciclo de Vida (ICV) dos principais insumos usados pela sociedade- energia, matérias- primas,etc. O presente trabalho faz parte de uma projeto conduzido pelo GP2- Grupo de Prevenção da Poluição, da Escola Politécnica/ USP, de disponibilização de bases brasileiras para ACV, sendo dedicado especificamente à geração de eletricidade. Para permitir sua realização no âmbito de uma dissertação de mestrado, adotou-se como simplificação a geração de eletricidade na usina hidrelétrica de Itaipu, responsável em 2000 por 22,4% da eletricidade consumida no país. Para construir o ICV realizou-se uma revisão bibliográfica sobre o uso da ACV em hidrelétricas, estabelecendo recomendações gerais. A seguir, estudou-se Itaipu quanto à sua obra civil e consumo de insumos na construção e operação por 100 anos, obtendo ao final um ICV com os aspectos ambientais mais significativos em termos da energia gerada (MWh). Neste contexto as fronteiras estabelecidas incluem: escavações e obras de terra; instalação e operação do canteiro de obras; transporte dos operários e de cimento, cinzas, aço estrutural e diesel para a obra; ciclo de vida do aço, cobre, cimento, diesel, óleos lubrificante e de transformador usados na barragem e equipamentos permanentes (considerando inclusive manutenção e substituição); e enchimento do reservatório. Com a discussão dos resultados pode-se demonstrar, além da importância do uso de dados homogêneos, que o ICV é extremamente sensível ao horizonte de análise (na verdade à energia gerada), o que confirma que a construção é a principal origem dos aspectos ambientais significativos. Outra conclusão é que cada hidrelétrica constitui um caso particular, não sendo possível atribuir valores típicos. No entanto, há indícios de que Itaipu, por seu alto fator de capacidade e potência instalada, possua um desempenho ambiental acima da média das hidrelétricas, principalmente no que se refere ao tempo de retorno da energia investida. As estimativas indicam que os processos que mais contribuem aos aspectos ambientais de hidrelétricas sejam: enchimento do reservatório; ciclo de vida do cimento e aço, e operação das máquinas de construção. As etapas de transporte parecem não ser de relevância, ao contrário do consumo de aço nos equipamentos permanentes. Em comparação com a geração termelétrica, as emissões atmosféricas e consumo de água do ciclo de vida de Itaipu se mostraram significativamente menores. No entanto há que se considerar que esta comparação se restringiu a estes aspectos. Ao final, conclui-se que resultados mais precisos sobre aspectos e processos de maior prioridade dependem da condução da etapa de Avaliação de Impactos da ACV, e portanto não se deve utilizar os resultados desta análise de inventário como único critério para tomada de decisões em planejamento energético. / The Life Cycle Assessment (LCA) has been proven to be an important environmental assessment tool, mainly due to its “focus on function", which allows the consideration of the environmental performance of products, itself a proceeding that has been more and more requested by different social actors. However, for LCA to be widely and trustfully used, the development of local data bases containing Life Cycle Inventories (LCI) of the most used inputs (energy, raw materials, etc.) is necessary. The present thesis is part of a project conducted by GP2- Group of Pollution Prevention - Escola Politécnica/ USP, which aims to develop and make available a Brazilian LCA data base. Specifically, it focuses electricity generation. In order to allow this project to be concluded in a masters degree context, it was adopted as a simplification the electricity generation in Itaipu Hydropower Plant, responsible for 22,4% of Brazilian consumption in 2000. As a first step towards the elaboration of the LCI, a review on LCA use on hydropower plants was conducted, establishing general recommendations. On the following, Itaipu project was studied concerning its initial civil works and the materials consumption on construction and operation within a 100 year period, obtaining as a result a LCI with the most significant environmental burdens in terms of generated energy (MWh). The system boundaries on this context includes: excavations and other earthen works; building site installation and operation; transportation of: workers, cement, ashes, structural steel and diesel; life cycle of steel, copper, cement, diesel, lubricant oil and transformer oil used on the dam and permanent equipment; (including maintenance and substitution); and reservoir filling. The results demonstrate, besides the importance of data homogeneity, that the LCI is extremely sensitive to the considered lifetime, which confirms that the construction phase is the main source of environmental burdens. Another important conclusion is that each hydropower plant is a particular case, and it is not possible to establish typical values for the environmental burdens. However there is an indication that Itaipu has a better environmental performance than other plants, mainly on respect to the energy pay back period, due to its high capacity factor and installed power. According to the estimates, the process which most contributes to the environmental burdens of hydropower plants life cycle are: reservoir filling; steel and cement life cycle; and operation of construction machines. Transport activities are of no relevance, however the steel consumption on permanent equipment is. Compared to thermal power, hydropower life cycle air emissions and water consumption are shown to be significantly lower. This comparison indeed is restricted only to this burdens. Finally, recommendations are presented, in the spirit of refining boundaries in the following studies, and the objectives attained are commented. It should be highlighted that all hypothesis and calculations are located in the Annex volume, being just referenced on the main text.