The growing industry of Information and Communication Technology requires higher computing capacity of data centers/technical sites. The air conditioning in data centers is the key to assure a sustainable computing environment. However, the traditional cooling systems cost are responsible for large environmental footprints especially on energy consumption and greenhouse gas emissions. As a result, a green innovation of data center cooling solutions is taking place. The telecommunication company Teliasonera is developing a high density data center cooling system - the “Green Room” and has been studying the environmental performance of this system using a Life Cycle approach. As an extension of the previous study, more aspects of the project i.e. the location, life span, alternative cooling solutions, energy recovery possibilities and uncertainty analysis is explored by using Life Cycle Assessment (LCA) methodology. The comparison of the locations of the Green Room indicates that the local temperature and electricity production sources are essential factors for the environmental performance of the Green Room. The analysis of the Green Room’s life span reveals that the utilization phase may not always cause the most significant impact during the whole life cycle of the Green Room. If the life span changes, the manufacture phase may predominate the life cycle of the Green Room. The comparative result of alternative cooling technologies addresses that utilizing “natural coolant” (e.g. geo cooling) is a key for sustainable cooling innovation as it would significantly reduce the environmental footprint of the cooling system. Besides, heating a single building (partly) by the waste heat generated from the Green Room could save 30% of cumulative energy input and could reduce more than half of the total environmental impact. Additionally, results uncertainties caused by the choice of different LCIA methods are discussed in the end of the study. / The Teliasonera Green Room Concept for high and mid density of ICT equipment

Over the past decades, cost-effectiveness principle or cost-benefit analysis has been employed oftentimes as a typical assessment tool for the expansion of drinking water utility. With changing public awareness of the inherent linkages between climate change, population growth and economic development, the addition of global change impact in the assessment regime has altered the landscape of traditional evaluation matrix. Nowadays, urban drinking water infrastructure requires careful long-term expansion planning to reduce the risk from global change impact with respect to greenhouse gas (GHG) emissions, economic boom and recession, as well as water demand variation associated with population growth and migration. Meanwhile, accurate prediction of municipal water demand is critically important to water utility in a fast growing urban region for the purpose of drinking water system planning, design and water utility asset management. A system analysis under global change impact due to the population dynamics, water resources conservation, and environmental management policies should be carried out to search for sustainable solutions temporally and spatially with different scales under uncertainties. This study is aimed to develop an innovative, interdisciplinary, and insightful modeling framework to deal with global change issues as a whole based on a real-world drinking water infrastructure system expansion program in Manatee County, Florida. Four intertwined components within the drinking water infrastructure system planning were investigated and integrated, which consists of water demand analysis, GHG emission potential, system optimization for infrastructure expansion, and nested minimax-regret (NMMR) decision analysis under uncertainties. In the water demand analysis, a new system dynamics model was developed to reflect the intrinsic relationship between water demand and changing socioeconomic iv environment. This system dynamics model is based on a coupled modeling structure that takes the interactions among economic and social dimensions into account offering a satisfactory platform. In the evaluation of GHG emission potential, a life cycle assessment (LCA) is conducted to estimate the carbon footprint for all expansion alternatives for water supply. The result of this LCA study provides an extra dimension for decision makers to extract more effective adaptation strategies. Both water demand forecasting and GHG emission potential were deemed as the input information for system optimization when all alternatives are taken into account simultaneously. In the system optimization for infrastructure expansion, a multiobjective optimization model was formulated for providing the multitemporal optimal facility expansion strategies. With the aid of a multi-stage planning methodology over the partitioned time horizon, such a systems analysis has resulted in a full-scale screening and sequencing with respect to multiple competing objectives across a suite of management strategies. In the decision analysis under uncertainty, such a system optimization model was further developed as a unique NMMR programming model due to the uncertainties imposed by the real-world problem. The proposed NMMR algorithm was successfully applied for solving the real-world problem with a limited scale for the purpose of demonstration.

Global food production has been recognized as the single largest driver of environmental degradation and transgression of planetary boundaries. Providing healthy food sustainably to a growing, mostly urban population will require radical changes to the food system. Indoor urban agriculture has been proposed as a promising alternative that reduces the distance between farm and fork, provides fresh quality food shortly after harvest, efficiently uses space by vertical expansion, and enables year-round cultivation protected by weather variations and climate deregulation. The development of indoor urban agriculture has traditionally manifested as verti- cal hydroponic systems cultivating leafy greens, but the interest in urban mushroom farming has lately been rising, both in Sweden and internationally. However, a knowledge gap on the environmental impacts of these systems hampers the possi- bility to develop them sustainably. This study aims to fill this gap by conducting an attributional cradle-to-market life cycle assessment of a theoretical urban under- ground oyster mushroom farm in Stockholm. Per kg packaged and delivered grey oyster mushrooms (Pleurotus ostreatus), the potential environmental impacts were estimated as the following - climate change: 2.45 kg CO2-eq, freshwater eutrophication: 6.76E-04 kg P-eq, fossils: 80 MJ, dissipated water: 3.29 m3 water-eq, and land use: 149 points. For the investigated impact categories the findings suggest that the three main environmental hotspots, in descending order, in general, are the farm’s electricity requirement, especially for fossils and dissipated water, the substrate materials, which is largely contributing to the land use impact, and the PET packaging of the final product, particularly for climate change and freshwater eutrophication. The results indicate that the cooling load for fruiting represents the majority of the farm’s electricity consumption. The spawn and wheat straw are the main contributors to the substrate mixture’s impact, and regarding climate iii change, the transportation by truck of the spawn and wheat straw pellets are im- portant factors. The life cycle of the PET packaging boxes and the PE growing bags have an especially important climate change contribution due to their production, transportation, and waste incineration.  By indicating which processes, energy, and material flows most contribute to urban underground oyster mushroom farming’s environmental impact, this study gives insights on improvement priorities and help steer the sector towards ecologically sustainable development. To guide ecodesign, future studies should explore and assess the environmental implications of different options, such as substrate materials, substrate preparation methods, packaging materials, and the reuse of different urban residues. / Global livsmedelsproduktion har erkänts som den enskilt största drivkraften bakommiljöförstöring och  överskridandet av planetens gränser. Att hållbart tillgodosehälsosam mat till en växande, mestadels urban befolkning kommer att kräva radikalaförändringar av livsmedelsystemet. Urban inomhusodling föreslås som ett lovande alternativ som året om, skyddat mot vädervariationer och klimatförändringar förser färska livsmedel kort efter skörd, minskar avståndet mellan produktion och konsumption och effektivt utnyttjar yta genom vertikal expansion. Utvecklingen av urban inomhusodling har traditionellt manifesterats som vertikala hydroponiskaodlingssystem av bladgrönsaker och örter, men på senare tid har intresset för stadsodling av svamp ökat, både i Sverige och internationellt. En kunskapslucka om dessa systems miljöpåverkan hämmar dock möjligheten att utveckla dessa på ett hållbart vis. Den här studien syftar till att fylla denna lucka genom att genomföra en bokföringsbaserad livscykelanalys från vagga-till-marknad av en teoretisk underjordisk stadsodling av ostronskivling i Stockholm. Per kg förpackad och leverera dostronskivling (Pleurotus ostreatus ), uppskattas den potentiella miljöpåverkan som följande klimatavtryck: 2,45 kg CO2-eq, sötvattensövergödning: 6,76E-04 kg P-eq, fossila resurser: 80 MJ, vattenanvändning: 3,29 m3 vatten-eq, och markanvändning: 149 poäng. För de fem undersökta miljökategorierna tyder resultatet på att de tre största bidragsfaktorerna, generellt och i fallande ordning är stadsodlingens elbehov, i synnerhet för fossila resurser och vattenanvändning, substratmixen,framförallt rörande markanvändning, och PET-förpackningen för slutprodukten, speciellt gällandes klimatpåverkan och sötvattensövergödning. Resultatet indikerar att kylbehovet under fruktifikationen står för huvuddelen av odlingsystemets elförbrukning. Myceliet och vetehalmen är de främsta bidragarna till substratmixens miljöpåverkan, och gällande klimatavtryck är transporten via lastbil av mycelieti och vetehalmpelletsen viktiga faktorer. Livscykeln för PET-förpackningen och PE-odlingspåsarna har ett särskilt viktigt bidrag till produktens klimatpåverkan på grund av deras produktion, transport och avfallsförbränning. Sammanfattningsvis kan denna studie, genom att indikera vilka processer, energi-och materialflöden som mest bidrar till miljöpåverkan av underjordisk stadsodling av ostronskivling, belysa prioriteringsomr ̊aden och därmed styra sektorn mot enekologiskt hållbar utveckling. F ̈or att vägleda ekodesign bör framtida studier belysa miljökonsekvenserna av olika alternativ så som substratmaterial, substratberedningsme-toder och förpackningsmaterial samt återanvändning av olika urbana avfallsflöden.

The United Nations projects that by the year 2050, there will be as many as 9.7 billion people on earth (UN, 2019). Along with the world population growth, the demand for food production will be increased. On the other side, agriculture plays a crucial role in global warming, increasing food production challenges. Thus, more sustainable methods should be chosen to respond to population demand and decrease the impact of agricultural activities on climate change. One of these alternative methods is Urban farming, specifically hydroponic vertical farming, in which the food is produced indoors under exceptional conditions as using artificial lighting and less water. Hydroponic vertical farming has several benefits, higher production per area, a controlled environment, less land usage, less water consumption, etc.  Vertical farms use LEDs as lightning sources to help photosynthesis; LEDs produce a massive amount of excess heat, which will be released to the environment and impact global warming. Therefore, a solution should be found to use the excess heat for other purposes instead of releasing it into the environment. In this study, the environmental performance of SweGreen’s hydroponic vertical farm will be assessed using a Life cycle assessment. The SweGreen hydroponic farm is located in a basement of a host building in Stockholm, Sweden. There is a symbiotic network between the farm and the host building where the farm provides the building with excess heat produced from the LEDs and, in return, gains carbon dioxide from the building. The result of this study shows that symbiotic network can decrease the impact of agriculture and excess produced heat, where the required heat for the building will be replaced from district heating by the produced excess heat. The symbiotic development between the host building and the farm will benefit the farm in various aspects and highlights the importance of urban symbiosis to reduce the impacts. / Enligt prognoser av Förenta Nationerna ska leva 9.7 billion människor på jorden till och med 2050 (FN, 2019). Världens befolkningstillväxt orsakar ökade efterfrågningar på livsmedelsproduktion. Tillsammans med de här ökade efterfrågningarna behov av jordbruk och dess produktioner ska ökas. De ökningarna skaffar seriösa utmaningar och oror Global uppvärmning. Därför behöver världen nya hållbara metoder att kunna hitta bra lösningar som minskas sådana påverkningar på klimatförändringarna. En av de nya hållbara metoderna är Urban Farming och speciellt hydroponiskt vertikalt jordbruk. Med denna metod livsmedel produceras inomhus med hjälpen av konstgjord belysning. Under de kontrollerade situationer ska mötas högre produktion per område och mindre vattenkonsumtion.   Lysdioder (LEDs) bidrar behov av belysning för fotosyntesprocess i Vertikal Farms. Dock släpper LEDs ut en enorm mängd överskottsvärme i miljön som har en direkt påverkan på globala uppvärmningen. En bra lösning för detta problem är att hittas ett sätt att använda överskottsvärmen för andra ändamål. I den här studien ska granskas miljöprestandan för SweGreen’s hydroponic vertikal farm med hjälp av en livscykelanalys. Gården ligger i Stockholm, Sverige. Det finns ett symbiotiskt nätverk mellan gården och vårdbyggnaden där levereras LEDs överskottsvärmen för byggnaden och fås koldioxid från den.   Resultatet av denna studie provar att symbiotiska nätverken kan minska påverkan av producerad överskottsvärmen på klimatförändringarna och Global uppvärmning.Symbiotiska utvecklingen mellan vårdbyggnaden och gården är intressant från olika aspekter och är viktig att minska påverkningarna på miljön.

With the rapid increase of renewable energy in the electricity grids, the need for energy storage continues to grow. One of the technologies that are gaining interest for utility-scale energy storage is lithium-ion battery energy storage systems. However, their environmental impact is inevitably put into question against lead-acid battery storage systems. Therefore, this study aims to conduct a comparative life cycle assessment (LCA) to contrast the environmental impact of utilizing lithium-ion batteries and lead-acid batteries for stationary applications, specifically grid storage. The main tools in this study include Microsoft Excel for the life cycle inventory and OpenLCA for life cycle modelling and sensitivity analysis. In this research, a cradle-to-grave LCA for three lithium-ion battery chemistries (i.e. lithium iron phosphate, nickel cobalt manganese, and nickel cobalt aluminium) is conducted. The impact categories are aligned with the Environmental Footprint impact assessment methodology described by the European Commission. The standby grid operation scenario is considered for estimating the environmental impacts, where the batteries would deliver 4,800 kWh of electric energy throughout 20 years. Consequently, the functional unit will be in per kWh energy delivered. The lead-acid battery system has the following environmental impact values (in per kWh energy delivered): 2 kg CO2-eq. for climate change, 33 MJ for fossil resource use, 0.02 mol H+-eq. for acidification, 10-7 disease incidence for particulate emission, and 8x10-4 kg Sb-eq. for minerals resource use. Going back to the lithium-ion batteries systems, for the climate change and fossil resource use impact categories, the best performer is found to be the nickel cobalt aluminium (NCA) lithium-ion battery, with 46% and 45% less impact than lead-acid for the respective categories. On the other hand, the nickel manganese cobalt (NMC) was the best for the acidification and particulate emission impact categories with respective 65% and 51% better performance compared to lead-acid batteries. Finally, for the minerals and metals resource use category, the lithium iron phosphate battery (LFP) is estimated to be the best performer, which is 94% less than lead-acid. To conclude, the life cycle stage determined to have the largest contribution for most of the impact categories was the use stage, which then becomes the subject to a sensitivity analysis. The sensitivity analysis was done by varying the renewable contribution of the electricity grids in the use phase. Overall, the lithium-ion batteries systems have less environmental impact than lead-acid batteries systems, for the observed impact categories. The findings of this thesis can be used as a reference to decide whether to replace lead-acid batteries with lithium-ion batteries for grid energy storage from an environmental impact perspective. / Med den snabba ökningen av förnybar energi i elnäten, fortsätter behovet av energilagring att växa. En av de tekniker som växer intresse för energilagring på nyttan är litiumjon batteriets energilagringssystem. Emellertid, deras miljöpåverkan ifrågasätts oundvikligen mot blysyrabatteri lagringssystem. Därför syftar denna studie till att göra en komparativ livscykelanalys (LCA) för att komparera miljöpåverkan av att använda litiumjonbatterier och blybatterier för stationära applikationer, särskilt för nätlagring. I denna forskning genomfördes en vagga-till-grav-LCA (eller cradle-to-grave i engelska) för tre litiumjonbatterikemi (litium järn fosfat, nickel kobolt mangan, och nickel cobalt aluminium). Effektkategorier anpassades till miljökonsekvensbedömning metoden som beskrivs av Europeiska kommissionen. Det användningsfall scenariot för batterierna var standby läget, där batterierna leverera 4800 kWh elektrisk energi för 20 år. Följaktligen den funktionella unit är i ‘per kWh levererad energi’. Blysyrabatteriet hade följande ungefärliga miljöpåverkansvärden (i per kWh levererad energi): 2 kg CO2-eq. för climate change, 33 MJ för fossil resource use, 0.02 mol H+-eq. för acidification, 10-7 disease incidence för particulate emission, and 8x10-4 kg Sb-eq. för minerals resource use. Tillbaka till litiumjonbatterierna, för climate change och fossil resource use resursanvändnings kategorier, den bäst presterande var litiumjonbatteriet nickel kobolt aluminium (NCA). Det hade 46% och 45% mindre påverkan än blysyrabatteriet för respektive kategori. Å andra sidan, var nickel mangan kobolt (NMC) bäst för acidifcation och particulate emission kategorier. De är 65% och 51% bättre än blysyra för kategorierna. Slutligen, litium järn fosfat batteriet (LFP) är det bäst presterande för resource use of minerals and metals kategoriet, vilket det är 94% mindre än blysyra. Avslutningsvis, det livscykelstadier som var bestämt att ha det största bidraget för de flesta av påverkningskategorierna är användningsstadiet, som sedan blir föremål för en känslighetsanalys. I slutändan, litiumjonbatterierna ha mindre miljöpåverkan än blybatterier i detta projekt, för de observerade slagkategorierna. Resultaten av denna avhandling kan sedan användas som referens för att avgöra om bly-syrabatterier ska ersättas med litiumjonbatterier för energilagring ur ett miljöeffektperspektiv.

This study compared the Global Warming Potential (GWP) impact of two single-family dwellings situated in Halmstad and Norrköping. The aim of this thesis work is to investigate how building materials types, material quantities, and geographical boundaries affect the Life Cycle Assessment (LCA) results. This study focuses on climate declaration (A1-A5) LCA stages and was conducted in collaboration with Fiskarhedenvillan. The study uses a comparative LCA of various building components and materials. One Click LCA student license was used to calculate the CO2e emissions from the GWP impact category. The study found that the building in Halmstad generated 6,3% lower CO2e emissions compared to the building in Norrköping. The reason mainly was affected by the use of roofing materials. The building in Halmstad used reinforced bitumen while the building in Norrköping used concrete tile roofing. The study investigates that reinforced bitumen generates lower emissions in A1-A4 stages compared to concrete. The geographical boundaries affect the A4 stage. The building in Halmstad generated higher CO2e emissions compared to the building in Norrköping as it has long distances to the building materials suppliers. The research verifies that the A1-A3 stages considerably generate most of the emissions (70-80%) compared to A4 and A5. The A5 stage results remain the same per meter square of both dwellings considering the use of generic data from One Click LCA.

Humans spend around 80 percent of their lifetime indoors. The humidity level plays an essential part in indoor climate, both in non-industrial applications, such as thermal comfort, and industrial ones. Dehumidification is a technology in the field of thermal comfort and indoor climate to control humidity levels. The need for the technology is essential for maintaining indoor humidity levels and lowering dew points. Based on the lack of studies that focus on the complete life cycle of the given dehumidification technology as well as the recently introduced EU Taxonomy there is an urgent need to evaluate the environmental impacts of the dehumidification systems. In this thesis, a comparative Life Cycle Assessment (LCA) is performed for two desiccant wheel dehumidifiers with industrial application driven fully by electric energy The intent of the LCA is to quantify the environmental performance of the two dehumidifier systems throughout their lifetime. The scope of this study is cradle-to-grave and includes four main life stages: cradle-to-gate, usage, maintenance and end-of-life. The objective is to identify the main drivers of selected environmental impact categories in each life phase and suggest areas of improvement. Seven categories are chosen based on the ReCiPe 2016 impact assessment method and that are related to the planetary boundaries. The two commonly available dehumidifiers will be analysed separately and in comparison. The functional unit used is 1 kg of water removed from the air which is independent of the performance of the system and focuses only on the wanted effect of humidity control. A base case is defined and scenarios are developed to cover different operational modes.  It is found that the usage stage which mainly consists of electricity demand contributes the most, varying between 65% and 99% of the overall impact in all categories. The cradle-to-gate stage, which shows the second biggest impact, has its most significant share in fine particulate matter formation, caused by the equipment for pre-treatment of air. Maintenance has the biggest variation depending on the scenario and application of the dehumidifiers where the number of maintenance occasions can vary significantly. This stage is however less crucial in the selected base case based on its small impact in most categories. End-of-life is insignificant for the results of this study having an average impact of less than 1%. The scenario analysis shows that a significant variation of the impact during usage is expected for different locations. This is mainly caused by the changing composition of the grid electricity which is identified overall main driver. The key parameters that influence the outcomes of this study are the operational hours of the systems, the target supply humidity as well as the climatic data. Potential for improvement is seen for an increased recycled content during the cradle-to-gate stage, the integration of sustainable energy technology as well as the connection of the systems to energy-efficient equipment during usage. Finally, it is concluded that an increase in material consumption may be tolerated by the systems if the energy performance is improved due to the dominating burden during the usage stage. The presented study may serve as example on how the EU Taxonomy can be applied within the field of dehumidification regarding environmental sustainability. It can also be used as a reference for further studies including the complete life cycle of dehumidifiers. Additional work may include other configurations of desiccant wheel dehumidifiers and extension to different assessment methods. / Människor spenderar cirka 80 procent av livet inomhus. Fuktighetsnivån är en viktig del av inomhusklimatet, både inom icke-industriella applikationer, såsom termisk komfort och industriella användningsområden. Avfuktning är en teknologi inom klimatkontroll inomhus och avlägsnar vattnet ur en luftström för att tillföra torr luft i rum. Den är väl ägnad om låga daggpunkter krävs. Möjliga användningsområden inom industrin är lagerutrymmen och förpackningsanläggningar, batteriproduktion, datacenter och farmaceutiska laboratorier. Denna studie har utförts eftersom det endast hittats ett fåtal studier som inkluderar hela livscykeln av sorptionsavfuktare. Utöver det så har EU taxonomin nyligen införts och den kan vara relevant för denna teknologi. Det finns därför ett behov att evaluera miljöpåverkan av dessa avfuktningssystem. I detta arbete utförs en jämförande livscykelanalys (LCA) av två rotorsorptionsavfuktare som används inom industrin och drivs av elektrisk energi. Meningen med denna LCA är att kvantifiera miljöpåverkan av de två systemen under hela livscykeln. Omfattningen av denna studie är ”från vaggan till graven” (eng. cradle-to-grave) och inkluderar fyra faser: tillverkning (eng. cradle-to-gate), användning, underhåll och demontering (eng. end-of-life). Syftet med arbetet är att kartlägga de centrala processer som driver miljöpåverkan, baserat på utvalda indikatorer och undersöka förbättringspotentialen. Sju kategorier från ReCiPe 2016 (som är en metod för miljökonsekvensbedömning) har valts ut för det baserat på de planetariska gränserna (eng. planetary boundaries). De två luftavfuktare analyseras enskilt och i jämförelse med varandra. Den funktionella enheten definieras som 1 kg vatten som tagits bort ur luften. Denna är oberoende av prestandan av systemet och beskriver endast avsedd effekt som är fuktighetskontroll. Utöver ett grundscenario har även olika scenarier utvecklats som beskriver varierande användning av avfuktaren.  Resultaten visar att användningen som mestadels består av elförbrukningen bidrar som mest till miljöpåverkan i alla kategorier med en andel mellan 65% och 99%. Tillverkningsfasen har näst störst påverkan av alla livsfaser och är mest relevant för fina partiklar. Detta orsakas av utrustningen för förbehandling av luften. Underhållet visar störst variation beroende på scenariot och användningen av avfuktaren eftersom antal underhållningstillfällen kan avvika mycket. Denna livsfas är däremot mindre relevant i grundscenariot eftersom den utgör endast en liten andel av den totala påverkan. Demontering är irrelevant för resultaten och utgör i genomsnitt mindre än 1%. Scenarioanalysen visar att en stor variation väntas för olika användningsställen eftersom produktionen av elen påverkar resultaten betydligt. De avgörande parametrar i denna studie är drifttimmar, målvärdet för fukthalten och klimatet. Förbättringspotential anses finnas i andelen återvunnet material i produktionsfasen, såsom integrering av hållbar energiteknik och energieffektiva lösningar under användningen. Det konstateras att en ökad konsumtion av material kan vara gynnsamt om detta reducerar påverkan under användningen. Detta är baserat på den tydliga skillnaden i påverkan under drift jämfört med de resterande livsfaser. Studien kan ses som exempel hur EU taxonomin för miljömässig hållbarhet skulle kunna appliceras inom avfuktning. Den kan också användas som referens för ytterligare studier inom området av livscykelanalys. Fortsatt arbete kan utökas till flera konfigurationer av rotorsorptionsavfuktare, såväl som inkluderandet av andra metoder för miljökonsekvensbedömning.

Many environmental compartments are acknowledged transmission routes for infectious diseases, antibiotic resistance, and anthropogenic pollution. The need for environmental sensing has consistently been stressed as a means to minimize public health threats caused by such contaminants. Many analytical detection techniques have been developed and applied for environmental sensing. However, these techniques are often reliant upon centralized facilities and require intensive resources. For these reasons their use can be challenging under resource-constrained conditions characterized by poor water, sanitation, and hygiene (WASH) services. In this dissertation, we developed biotechnology- and/or nanotechnology-advanced analytical tools for environmental sensing that have potential for future application in regions with poor WASH services. First, loop-mediated isothermal amplification (LAMP) and nanopore sequencing were applied to develop assays for the detection of SARS-CoV-2, the causative agent of COVID-19, in wastewater samples. Second, surface-enhanced Raman spectroscopy (SERS) was applied for environmental detection of a range of analytes. Gold nanoparticle (AuNP)-based SERS substrates were fabricated by droplet evaporation-induced aggregation on a hydrophobic substrate. These SERS substrates were then applied for the detection of antibiotic resistance genes (ARGs) and other environmental contaminants (e.g., dye or hydrophobic organic contaminants). In a separate study, Au nanostructured SERS substrates were fabricated and applied for pH sensing in a range of environmental media. Finally, the environmental impact of an AuNP-based colorimetric detection assay was assessed via life cycle assessment. / Doctor of Philosophy / Environmental sensing is an important means to intervene against public health threats of infectious diseases and environmental contaminants. However, currently available analytical tools for environmental samples often require intensive resources that are not available in low- and middle-income countries. In this dissertation, we developed biotechnology and/or nanotechnology advanced analytical tools for environmental sensing that have potential future application applied under resource-constrained conditions. First, we applied loop-mediated isothermal amplification (LAMP) and nanopore sequencing to develop detection assays for SARS-CoV-2, the causative agent of COVID-19, in wastewater samples. Second, we applied surface-enhanced Raman spectroscopy (SERS) to develop assays for environmental analytes. We fabricated SERS substrates by evaporation-induced aggregation of gold nanoparticles (AuNPs) on a hydrophobic substrate and applied these for the detection of antibiotic resistance genes (ARGs) and other environmental contaminants. In addition, Au nanostructured SERS substrates were fabricated and applied for pH sensing in a range of environmental media. Finally, we used life cycle assessment to quantitatively evaluate the environmental impacts of an AuNP-based sensing applications.

In-service pavements require maintenance and rehabilitation (MandR) interventions to keep them in compliance with structural and functional standards. With the increased focus on the sustainability of our roadway systems, it has become important to document the cost and environmental impacts of different MandR strategies over the life cycle of the pavement to facilitate project selection decisions in the future. Asphalt pavement recycling, while cost-effective and environmentally friendly compared to other traditional MandR treatments, still faces some widespread implementation push-back, leading to policy enactments by the FHWA aimed at encouraging the use of recycling in road projects. Many agencies and contractors have cited the lack of project selection criteria, and uncertainty about long-term performance of these recycling alternatives as reasons impeding rapid implementation of these treatments in road projects. One of the gray areas of the FHWA's 2015 Recycled Material Policy in project selection was, until recently, the lack of guidelines or tools for the assessment of the environmental suitability of candidate MandR treatments. Today, it is almost impossible to evaluate the environmental suitability of various recycling-based end-of-service-life treatments because available databases do not have relevant information on the details of unit processes, construction equipment and activities, and use-stage roughness data. Development of future MandR plans throughout the service life of pavements rehabilitated with recycling-based treatments is somewhat limited as deterioration is not fully understood. Also, available modeling tools no not address all LCA phases, or in cases where they do, key life cycle phases including the MandR, and use phases are not well covered due to the lack of quantification highlighted earlier. To address the highlighted concerns, this dissertation developed a user-friendly comprehensive LCA tool that was further validated with a case study to quantify the service life (when the pavement has reached a critical threshold performance value) and potential environmental benefits of pavement recycling projects executed by the Virginia Department of Transportation over the past decade. The tool, pySuPave, includes an excel spreadsheet user-inputs interface, and database of economic flows for unit processes used in the production of pavement materials and subsequent construction of the pavement system, considering transportation of materials and construction machinery to plants and construction site. A python-based program was used to perform matrix-based computations to generate the environmental burdens from the available public LCA Ecoinvent database. A substantive part of the dissertation was dedicated to evaluating the performance of in-service pavements rehabilitated with cold recycling and full-depth reclamation treatments, focusing on developing pavement performance prediction models (PPPM) that goes on to improve modelling of the MandR and use stages in the pavement LCA and ultimately bridges the knowledge gap on how these treatments perform in the long term. This part of the dissertation was presented in two chapters; trends in pavement recycling and performance data collection, and development of PPPMs for recycled asphalt pavements. The first provides an update and examines the current state of pavement recycling techniques, highlighting trends in the various recycling methods, examining what is and is not working from the agency perspective, and assessing the progress made in the last decade through a web-based survey. The survey results did not indicate significant changes in the adoption of the asphalt pavement recycling concept in the last decade. However, recycling techniques, such as hot in-place recycling, are being used less and more agencies seem to be adopting lower temperature techniques such as cold in-place recycling, cold central plant recycling and full depth reclamation. Improvements in mix design methods were noticeable, as more agencies have adopted contemporary methods, such as the Superpave design. Among states, very few agencies collected performance data for completed asphalt pavement recycling projects. The second chapter on performance focused on developing individual and family-type PPPMs from the data collected from the states of Virginia and Colorado, respectively. While regression modeling forms the backbone of the approach used, the chapter also presents an approach to developing family-type models using functional data analysis to find groups of projects with similar deterioration trends. In the case of Colorado, cold in-place recycling (CIR) projects completed with an initial IRI between 71 and 91 in/mi are most likely to deteriorate at an average group rate of 1.37 in/mi/year. Similarly, full depth reclamation (FDR) projects will most likely deteriorate following an average group rate of 1.40 in/mi/yr, with an initial IRI between 52 and 70 in/mi. These projects will stay in service well over 30 years if a threshold IRI of 140 in/mi were used a failure criterion. For the individual roughness models developed for VDOT, the initial IRI values and the rate of change for the treatments analyzed were found to range between 48 and 85 in/mi and between 0.70 and 5.20 in/mi/year, respectively, depending on the recycling method and type of stabilization treatment. Finally, a context-based life cycle assessment case study was conducted to benchmark and compare the environmental impacts associated with rehabilitating a low-volume road with various recycled-based and equivalent conventional methods. Several impact indicators were assessed but only the global warming (GW) score and the single score index that combines all the environmental impact indicators into a single number using normalization and weighting factors were reported in this study for the sake of brevity. Four restorative maintenance projects including two CIR (4-in. HMA over a 5-in. CIR with foamed asphalt and emulsion stabilization), one cold central plant recycling (CCPR): 4-in. HMA over a 5-in. foamed asphalt CCPR (CCPR FA), and one non-recycling structural overlay (8-in. HMA over an existing pavement) were evaluated. In addition, the following reconstruction projects were assessed; two FDR (4-in. HMA over a 12-in. FDR with foamed asphalt with 1% cement additive, and a 4-in. HMA over 10.5-in. cement stabilized FDR), and a non-recycling reconstruction project (a new reconstruction project with 8-in. HMA over a 16-in. aggregate base and subbase). The functional unit was a two lane-mile length, 12 feet wide project with a traffic volume of 1000 vehicles (3% trucks) and the analysis was conducted for 50 years. The GW score and a few other impact indicators showed an increase in the observed results where cement is used as a main stabilizer or as an additive. Between the asphalt stabilized projects, the difference in impact scores is only seen when cement is used as an additive as highlighted in the case of foamed asphalt applications. Even for the low-volume road under study, the use stage contributes the largest share to global warming and is—among several factors—attributed to the initial surface roughness of completed projects. Thus, for state DOTs looking to reduce the environmental footprints for road infrastructure projects and achieve federal legislative goals, building smoother roads and taking steps to keep the annual deterioration rate low would be an important measure, in addition to pavement recycling. Comparing the projects based on the overall single score derived from weighting factors from the National Institute of Standards and Technology (NIST) ranks the projects as follows (listed in order decreasing impacts per rehabilitation category); restorative maintenance projects: T. OVERLAY (non-recycling structural overlay—8 in. HMA over an existing pavement) - 1.06 pts, CCPR FA (4 in. HMA over a 5 in. cold central plant recycling with foamed asphalt) - 1.02 pts, CIR FA (4 in. HMA over a 5 in. cold in-place recycling with foamed asphalt) - 1.00 pts, CIR AE (4 in. HMA over a 5 in. cold in-place recycling with emulsion)- 0.86 pts; reconstruction projects: RECONS (a new reconstruction project—8 in. HMA over a 16 in. aggregate base and subbase) -1.42 pts, FDR FA+C (4 in. HMA over a 12 in. FDR with foamed asphalt with 1% cement additive) - 1.15 pts, FDR C (4 in. HMA over 10.5 in. cement stabilized FDR) - 1.02 pts. / Doctor of Philosophy / Due to harsh environmental conditions and continual damage from moving traffic, highway pavements or roadways deteriorate and grow weak over time. Throughout their life in service, different maintenance and rehabilitation (MandR) activities are performed with the intention of slowing down the deterioration to always keep the highway at a certain level of service to road users. For a long time, these MandR activities have included the use of virgin materials in techniques ranging from minor treatment applications such as fog seals, chip seals, thin overlays through more heavy treatments such as mill and fills, thicker overlays all the way to total reconstruction. Other MandR alternatives include pavement recycling which reuses materials from the existing distressed roadways either in-place or at a nearby mobile plant have gained popularity among several state highway agencies over the last decade. The advantages of using the recycling alternatives compared to non-recycling options are many and have been known to include cost savings, less construction time, and low environmental footprint. Many highway agencies, however, have expressed the lack of information on project selection criteria and the uncertainty about long-term performance of these recycling alternatives as reasons impeding rapid and widespread implementation in road projects. Agencies need selection criteria to help them identify the right treatments to apply to the right road at the right time. In a bid to encourage the use of pavement recycling treatments, the Federal Highway Administration (FHWA) enacted the Recycled Materials Policy in 2006 (revised 2015) but the policy did not fully address certain aspects of project selection. Directives on assessing the environmental suitability of recycling projects, for instance, was not given. There are no tools with modern databases incorporating the various unit processes for pavement recycling to aid agencies carry out this environmental assessment. To address the highlighted concerns, we developed a user-friendly comprehensive environmental assessment tool called pySuPave as part of this dissertation. We later validated the tool with a case study to quantify the potential environmental benefits of pavement recycling projects executed by the Virginia Department of Transportation over the past decade. Next, we conducted a survey of the departments of transportation (DOT) around the United States and Canada to collect performance data from agencies with active in-place recycling programs. Approximately 18% of the DOTs surveyed were able to provide performance data. Data received from Colorado and Virginia were subsequently used to developed models to predict deterioration in recycled pavements. In the case of Colorado, CIR projects completed with an initial roughness (IRI) between 71 and 91 in/mi are most likely to deteriorate at a rate of 1.37 in/mi/year. Similarly, FDR projects will most likely deteriorate following an average group rate of 1.40 in/mi/yr, with an initial IRI between 52 and 70 in/mi. These projects will stay in service well over 30 years if a threshold IRI of 140 in/mi were used a failure criterion. For the individual roughness models developed for VDOT, the initial IRI values and the rate of change for the treatments analyzed were found to range between 48 and 85 in/mi and between 0.70 and 5.20 in/mi/year, respectively, depending on the recycling method and type of stabilization treatment Finally, we conducted an environmental assessment case study to benchmark and compare the environmental burdens i.e., global warming (GW) and other impacts associated with rehabilitating a low-volume road with various recycled-based and equivalent non-recycling methods. Four restorative maintenance projects including two CIR (4-in. HMA over a 5-in. CIR with foamed asphalt and emulsion stabilization), one CCPR (4-in. HMA over a 5-in. foamed asphalt CCPR [CCPR FA]), and one non-recycling structural overlay (8-in. HMA over an existing pavement) were evaluate. In addition, the following reconstruction projects were assessed; two FDR (4-in. HMA over a 12-in. FDR with foamed asphalt with 1% cement additive, and a 4-in. HMA over 10.5-in. cement stabilized FDR), and a non-recycling reconstruction project (a new reconstruction project with 8-in. HMA over a 16-in. aggregate base and subbase). The functional unit was a two lane-mile length, 12 feet wide project with a traffic volume of 1000 vehicles (3% trucks) and the analysis was conducted for 50 years. The study results showed that the recycling-based projects had lower overall environmental burdens compared to their equivalent non-recycling alternatives. The GW score and a few other environmental impact indicators were higher when cement is used as a main stabilizer or as an additive in the recycling projects. Between the asphalt stabilized recycling projects, the difference in impact scores is only seen when cement is used as an additive as emphasized in the case of foamed asphalt applications. Even for the low-volume roads under study, the use stage (when the project is open to road-users) in the pavement life cycle contributes the largest share to global warming and is—among several factors—attributed to the initial surface roughness of completed projects. Thus, for state DOTs looking to reduce the environmental footprints for road infrastructure projects and achieve federal legislative goals, building smoother roads and taking steps to keep the annual deterioration rate low would be an important measure, in addition to pavement recycling. The results from this research support the hypothesis that pavement recycling can reduce global warming and other environmental burdens compared to non-recycling methods. Therefore, agencies should encourage more pavement recycling programs.

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.