The question of how to design a congestion pricing scheme is difficult to answer and involves a number of complex decisions. This thesis is devoted to the quantitative parts of designing a congestion pricing scheme with link tolls in an urban car traffic network. The problem involves finding the number of tolled links, the link toll locations and their corresponding toll level. The road users are modeled in a static framework, with elastic travel demand. Assuming the toll locations to be fixed, we recognize a level setting problem as to find toll levels which maximize the social surplus. A heuristic procedure based on sensitivity analysis is developed to solve this optimization problem. In the numerical examples the heuristic is shown to converge towards the optimum for cases when all links are tollable, and when only some links are tollable. We formulate a combined toll location and level setting problem as to find both toll locations and toll levels which maximize the net social surplus, which is the social surplus minus the cost of collecting the tolls. The collection cost is assumed to be given for each possible toll location, and to be independent of toll level and traffic flow. We develop a new heuristic method which is based on repeated solutions of an approximation to the combined toll location and level setting problem. Also, a known heuristic method for locating a fixed number of toll facilities is extended, to find the optimal number of facilities to locate. Both heuristics are evaluated on two small networks, where our approximation procedure shows the best results. Our approximation procedure is also employed on the Sioux Falls network. The result is compared with different judgmental closed cordon structures, and the solution suggested by our method clearly improves the net social surplus more than any of the judgmental cordons.

Potential contamination from hazardous and solid waste landfills stemming from population increase, rapid industrialization, and the proliferation of assembly plants known as the maquiladoras, are of major concern in the U.S.-Mexican border area. Additionally, historical, current, and future stresses on the Hueco Bolson alluvial aquifer in the El Paso/Ciudad Juarez area due to excessive groundwater withdrawal can affect contaminant migration in the area. In the current study, an updated and improved threedimensional numerical groundwater flow and transport model is developed using a current Hueco Bolson groundwater availability model as its basis. The model with contaminant transport is required to access and characterize the extent of vulnerability of the aquifer to potential contamination from landfills in the El Paso/Ciudad Juarez border area. The model developed in this study is very capable of serving as the basis of future studies for water availability, water quality, and contamination assessments in the Hueco Bolson. The implementation of fate and transport modeling and the incorporation of the Visual MODFLOW® pre and post processor, requiring MODFLOW 2000 data conversion, enabled significant enhancements to the numerical modeling and computing capabilities for the Hueco Bolson. The model in the current research was also developed by employing MT3DMS©, ZONEBUDGET, and Visual PEST® for automated calibrations. Simulation results found that the Hueco Bolson released more water from storage than the aquifer was being recharged in response to increased pumping to supply the growing border area population. Hence, significant head drops and high levels of drawdown were observed in the El Paso/Ciudad Juarez area. Predictive simulations were completed representing scenarios of potential contamination from the border area sites. Fate and transport results were most sensitive to hydraulic conductivities, flow velocities, and directions at the sites. Sites that were located within the vicinity of the El Paso Valley and the Rio Grande River, where head differences and permeabilities were significant, exhibited the highest potentials for contaminant migration.

<p>The question of how to design a congestion pricing scheme is difficult to answer and involves a number of complex decisions. This thesis is devoted to the quantitative parts of designing a congestion pricing scheme with link tolls in an urban car traffic network. The problem involves finding the number of tolled links, the link toll locations and their corresponding toll level. The road users are modeled in a static framework, with elastic travel demand.</p><p>Assuming the toll locations to be fixed, we recognize a level setting problem as to find toll levels which maximize the social surplus. A heuristic procedure based on sensitivity analysis is developed to solve this optimization problem. In the numerical examples the heuristic is shown to converge towards the optimum for cases when all links are tollable, and when only some links are tollable.</p><p>We formulate a combined toll location and level setting problem as to find both toll locations and toll levels which maximize the net social surplus, which is the social surplus minus the cost of collecting the tolls. The collection cost is assumed to be given for each possible toll location, and to be independent of toll level and traffic flow. We develop a new heuristic method which is based on repeated solutions of an approximation to the combined toll location and level setting problem. Also, a known heuristic method for locating a fixed number of toll facilities is extended, to find the optimal number of facilities to locate. Both heuristics are evaluated on two small networks, where our approximation procedure shows the best results.</p><p>Our approximation procedure is also employed on the Sioux Falls network. The result is compared with different judgmental closed cordon structures, and the solution suggested by our method clearly improves the net social surplus more than any of the judgmental cordons.</p>

Reactive transport modeling is an important approach to understand water dynamics, mass transport and biogeochemical processes from the hillslope to the catchment scale. It has a wide range of applications in the fields of e.g. water resource management, contaminanted site remediation and geotechnical engineering. To simulate reactive transport processes at a hillslope or larger scales is a challenging task, which involves interactions of complex physical and biogeochemical processes, huge computational expenses as well as difficulties in numerical precision and stability. The primary goal of the work is to develop a practical, accurate and efficient tool to facilitate the simulation techniques for reactive transport problems towards hillslope or larger scales. The first part of the work deals with the simulation of water flow in saturated and unsaturated porous media. The capability and accuracy of different numerical approaches were analyzed and compared by using benchmark tests. The second part of the work introduces the coupling of the scientific software packages OpenGeoSys and IPhreeqc by using a character-string-based interface. The accuracy and computational efficiency of the coupled tool were discussed based on three benchmarks. It shows that OGS#IPhreeqc provides sufficient numerical accuracy to simulate reactive transport problems for both equilibrium and kinetic reactions in variably saturated porous media. The third part of the work describes the algorithm of a parallelization scheme using MPI (Message Passing Interface) grouping concept, which enables a flexible allocation of computational resources for calculating geochemical reaction and the physical processes such as groundwater flow and transport. The parallel performance of the approach was tested by three examples. It shows that the new approach has more advantages than the conventional ones for the calculation of geochemically-dominated problems, especially when only limited benefit can be obtained through parallelization for solving flow or solute transport. The comparison between the character-string-based and the file-based coupling shows, that the former approach produces less computational overhead in a distributed-memory system such as a computing cluster. The last part of the work shows the application of OGS#IPhreeqc for the simulation of the water dynamic and denitrification process in the groundwater aquifer of a study site in Northern Germany. It demonstrates that OGS#IPhreeqc is able to simulate heterogeneous reactive transport problems at a hillslope scale within an acceptable time span. The model results shows the importance of functional zones for natural attenuation process. / Modellierung des reaktiven Stofftranports ist ein wichtiger Ansatz um die Wasserströmung, den Stofftransport und die biogeochemischen Prozesse von der Hang- bis zur Einzugsgebietsskala zu verstehen. Es gibt umfangreiche Anwendungsgebiete, z.B. in der Wasserwirtschaft, Umweltsanierung und Geotechnik. Die Simulation der reaktiven Stofftransportprozesse auf der Hangskala oder auf größeren Maßstäbe ist eine anspruchsvolle Aufgabe, da es sich um die Wechselwirkungen komplexer physikalischer und biogeochemischen Prozesse handelt, die riesigen Berechnungsaufwand sowie numerischen Schwierigkeiten bezogen auf die Genauigkeit und die Stabilität nach sich ziehen. Das Hauptziel dieser Arbeit besteht darin, ein praktisches, genaues und effizientes Werkzeug zu entwickeln, um die Simulationstechnik für reaktiven Stofftransport auf der Hangskala und auf größeren Skalen zu verbessern. Der erste Teil der Arbeit behandelt die Simulation der Wasserströmung in gesättigten und ungesättigten porösen Medien. Das Anwendungspotential und die Genauigkeit verschiedener numerischer Ansätze wurden mittels einiger Benchmarks analysiert und miteinander verglichen. Der zweite Teil der Arbeit stellt die Kopplung der wissenschaftlichen Softwarepakete OpenGeoSys und IPhreeqc mit einer stringbasierten Schnittstelle dar. Die Genauigkeit und die Recheneffizienz des gekoppelten Tools OGS#IPhreeqc wurden basierend auf drei Benchmark-Tests diskutiert. Das Ergebnis zeigt, dass OGS#IPhreeqc die ausreichende numerische Genauigkeit für die Simulation reaktiven Stofftransports liefert, welcher sich sowohl auf die Gleichgewichtsreaktion als auch auf die kinetische Reaktion in variabel gesättigten porösen Medien beziehen. Der dritte Teil der Arbeit beschreibt zuerst den Algorithmus der Parallelisierung des OGS#IPhreeqc basierend auf dem MPI (Message Passing Interface) Gruppierungskonzept, welcher eine flexible Verteilung der Rechenressourcen für die Berechnung der geochemischen Reaktion und der physikalischen Prozesse wie z.B. Wasserströmung oder Stofftransport ermöglicht. Danach wurde die Leistungsfähigkeit des Algorithmus anhand von drei Beispielen getestet. Es zeigt sich, dass der neue Ansatz Vorteile gegenüber die konventionellen Ansätzen für die Berechnung von geochemisch dominierten Problemen bringt. Dies ist vor allem dann der Fall, wenn nur eingeschränkter Nutzen aus der Parallelisierung für die Berechnung der Wasserströmung oder des Stofftransportes gezogen werden kann. Der Vergleich zwischen der string- und der dateibasierten Kopplung zeigt, dass die erstere weniger Rechenoverhead in einem verteilten Rechnersystem, wie z.B. Cluster erzeugt. Der letzte Teil der Arbeit zeigt die Anwendung von OGS#IPhreeqc für die Simulation der Wasserdynamik und der Denitrifikation im Grundwasserleiter eines Untersuchungsgebietes in NordDeutschland. Es beweist, dass OGS#IPhreeqc in der Lage ist, reaktiven Stofftransport auf der Hangskala innerhalb akzeptabler Zeitspanne zu simulieren. Die Simulationsergebnisse zeigen die Bedeutung der funktionalen Zonen für die natürlichen Selbstreinigungsprozesse.

Although climate change is a global problem, specific mitigation measures are frequently applied on regional or national scales only. This is the case in particular for measures to reduce the emissions of land-based transport, which is largely characterized by regional or national systems with independent infrastructure, organization, and regulation. The climate perturbations caused by regional transport emissions are small compared to those resulting from global emissions. Consequently, they can be smaller than the detection limits in global three-dimensional chemistry-climate model simulations, hampering the evaluation of the climate benefit of mitigation strategies. Hence, we developed a new approach to solve this problem. The approach is based on a combination of a detailed three-dimensional global chemistry-climate model system, aerosol-climate response functions, and a zero-dimensional climate response model. For demonstration purposes, the approach was applied to results from a transport and emission modeling suite, which was designed to quantify the present-day and possible future transport activities in Germany and the resulting emissions. The results show that, in a baseline scenario, German transport emissions result in an increase in global mean surface temperature of the order of 0.01 K during the 21st century. This effect is dominated by the CO2 emissions, in contrast to the impact of global transport emissions, where non-CO2 species make a larger relative contribution to transport-induced climate change than in the case of German emissions. Our new approach is ready for operational use to evaluate the climate benefit of mitigation strategies to reduce the impact of transport emissions.

The efficiency to improve the water quality of industrial and municipal wastewater in a constructed wetland/filter basin treatment system was investigated. The wetland system was constructed in a closed phosphate mine used for clay settling and sand tailings in Polk County, Florida. During 18-months of monitoring the chemical/microbiological composition of treated wetland water remained relatively constant, despite significant seasonal variations in temperature, rainfall and humidity. The following changes in water quality between input and output were observed: substantial decrease of water temperature (up to 10°C), reduction of As, SO4, F, Cl, NO3, NO2, Br, Na, K, Ca, and Mg, change in pH from 9 to 6.5-7, increase of H2S (up to 1060 micrograms/L), and a change from positive to negative ORP. There were no exceedances of the primary drinking water standards, volatile organic compounds, synthetic organic compounds, and radionuclides, but a number of exceedances for the secondary drinking water standards (Al, F, Fe, Mn, color, odor, total dissolved solids, and foaming agents). The concentration of fecal and total coliform bacteria in the wetland water was high, but subsequently reduced during filtration in the filter basin from 30 - 730 and 1000 - 7000 count/100 mL to < 2 and < 100 count/ 100 mL, respectively. To resolve the complex hydrogeological conditions a combined isotope/chemical mass-balance approach was applied. The results were the following: (1) the composition of water in the wetland varied throughout the period of the study; (2) a change in isotopic composition along the wetland flow path; (3) the wetland contained mainly wastewater (88 - 100 %) during normal pumping operations; however, hurricanes and inconsistent pumping added low conductivity water directly and triggered enhanced groundwater inflow into the wetland of up to 78 %; (4) the composition of water in monitor wells was mostly groundwater dominated; however periodically seepage from a water body to the north was detected; and (5) seepage from adjacent water bodies into the wetland was not identified during operation, which would indicate a potential water loss from the wetland. To test if the wetland system could be a prospective pre-treatment option for water used in aquifer storage and recovery (ASR) scenarios, a set of bench-scale leaching experiments was carried out using rocks from the Avon Park Formation, the Suwannee Limestone and the Ocala Limestone. Since As in the Floridan Aquifer was mainly present as an impurity in the mineral pyrite the elevated iron and sulfide concentrations in the wetland water were thought to prevent pyrite dissolution. The experiments which covered a range of redox conditions showed that the amount of As released from the aquifer matrix was not perfectly correlated with the bulk rock As concentration, nor the redox state of the water. The following important results were obtained: (1) the highest concentration of As was leached from the Avon Park Formation and the lowest - from the Suwannee Limestone, although the Ocala Limestone had the lowest bulk rock As; (2) minor to no As was released using native Floridan groundwater; (3) Tampa tap water, which chemically and physically resembled the ASR injection water, caused the As leaching of up to 27 micrograms/L, which was higher than the As drinking water standard; (4) the wetland and filter basin waters caused the highest release of As (up to 68 micrograms/L), which was unexpected because those water types were less oxygenated than Tampa tap water and thus should be less aggressive; (5) the in-situ filtration of the wetland water through a 0.2 micrometer membrane resulted in a reduction of As from 30 microgram/L to 16 microgram/L; and (5) the UV treatment significantly reduced both fecal and total coliform bacteria, but facilitated the increase of DO in initial waters, a change from negative to positive ORP, and the increase of As concentration in leachates. The experiments confirmed that perturbations of native aquifer conditions caused the release of As from the Floridan aquifer matrix, although the reaction may not be as simple as the dissolution of pyrite by oxygen, but additionally governed by a complex set of factors including the ORP of the system, SO4²?/S², Fe³?/Fe²?, dissolved organic carbon and microbial activity. In addition, the trend of As leaching could be governed by a set of factors, such as the porosity and permeability of the aquifer matrix influencing the rate and degree of free water saturation, amount of pyrite to be exposed to the preferential water flow paths, limited surface reactivity of pyrite with favored reactions on fractured mineral surfaces, the concentration and the selective leaching of As from individual pyrite crystals. To characterize and verify the geochemical processes in the column experiments, the Geochemist's Workbench reactive transport models (React and X1t) were developed. Results from the models correlated well to those from the column experiments and confirmed the following: (1) the water-rock reaction between the aquifer matrix and native groundwater was favorable for pyrite stability preventing the release of As into solution; (2) the injection of oxidizing surface water into reducing native groundwater caused a change in redox potential of the system thus promoting the dissolution of pyrite, and (3) 1D reactive transport model of water-rock reaction between the aquifer matrix and surface water indicated a diverse behavior of As along the column, such as the oxidative dissolution of pyrite, mobilization and simultaneous sorption of As onto neo-formed HFO, followed by the reductive dissolution of HFO and secondary release of adsorbed As, and the potential non-oxidative dissolution of pyrite contributing the additional source of As to the solution.

A large-scale introduction of driverless trucks could start taking place during the next decade. While this could bring several economic benefits for freight transport actors and society, it may also change the freight transport system and exacerbate the negative effects of road transport. This thesis aims to increase the understanding of how an introduction of driverless trucks could materialize and impact the freight transport system in Sweden. Two overarching issues are addressed. The first is how freight transport patterns will change due to the impacts of driverless trucks on road transport supply. This is addressed in Paper 1 and Paper 2. The second issue, which is studied in Paper 3, is what factors are shaping the ongoing development towards an introduction of driverless trucks in Sweden. In Paper 1, the impact of driverless trucks on the costs for long-distance road freight transport is studied through a total cost of ownership analysis which shows that driverless trucks could enable cost reductions of around 30%-40% per ton-kilometer. A key determinant of the cost reduction is to what extent reduced driver costs will be offset by other forms of human labor that may be required for driverless truck operations. Other factors, including changes to the truck acquisition cost, have marginal importance. The cost-saving potential provides a strong motivation for freight transport actors to develop and adopt driverless trucks. In Paper 2, the impacts of driverless trucks on road transport demand, utilization of different truck types, modal split, and total logistics costs are studied by using the Swedish national freight transport model Samgods. Two scenario types are studied, one in which driverless trucks substitute manually driven trucks and one where driverless trucks capable of operating between logistics hubs are introduced as a complement to manually driven trucks. The analysis shows that in both scenarios, driverless trucks could reduce total costs for Swedish freight transport in the range of billions of SEK per year. Road transport demand and truck traffic volumes may increase significantly through modal shifts from rail and sea. This could lead to increased societal costs through, for instance, increased CO2 emissions and congestion which are, however, not quantified in the study. In Paper 3, an analysis of the innovation system of driverless trucks based on an interview study with actors involved in the development and introduction of driverless trucks in Sweden is presented. The findings suggest that there are several favorable factors for a successful introduction of driverless trucks, but also that the innovation system is characterized by a high degree of uncertainty related to what infrastructure will be required and available, what business models will be emerging, and which actors will be able to capitalize on the development and which actors that become marginalized in a future with driverless trucks. The findings from this thesis can be of interest for policymakers since it highlights potential benefits and challenges associated with driverless trucks from a transport-system perspective and the provided indicative quantitative estimates on system-level impacts offer a glimpse into a future freight transport system with driverless trucks. Also, the thesis highlights critical challenges for the innovation system of driverless trucks which could guide efforts to improve its performance. / Ett storskaligt införande av förarlösa lastbilar kan komma att inledas under det kommande årtiondet. Detta skulle kunna medföra flera nyttor för transportköpare, transportbolag och samhället i stort men kan också leda till betydande förändringar av godstransportsystemet och ökade negativa effekter från vägtransporter. Syftet med denna avhandling är att öka förståelsen för hur ett införande av förarlösa lastbilar kan ske samt påverka godstransportsystemet i Sverige. Två övergripande frågeställningar studeras. Den första är hur förarlösa lastbilar påverkar utbudet för lastbilstransporter och därigenom förändrar godstransportsystemet. Detta studeras i Artikel 1 och Artikel 2. Den andra frågeställningen är vilka faktorer som påverkar den pågående utvecklingen mot ett införande av förarlösa lastbilar, vilket studeras i Artikel 3. I Artikel 1 görs en analys av hur förarlösa lastbilar kan påverka kostnaden för långväga lastbilstransporter. Denna visar att förarlösa lastbilar kan minska den totala ägandekostnaden med runt 30-40% per tonkilometer jämfört med konventionella lastbilar. Avgörande för hur stor kostnadsbesparingen blir är i vilken utsträckning minskningar i förarkostnader vägs upp av andra lönekostnader som uppstår vid användning av förarlösa lastbilar. Andra faktorer, inklusive förändringar av inköpspriset på lastbilar, har endast marginell påverkan. Den potentiella kostnadsbesparingen utgör ett tydligt motiv för godstransportaktörer att införa förarlösa lastbilar. I Artikel 2 studeras effekterna av förarlösa lastbilar på efterfrågan på lastbilstransporter, användningen av olika lastbilstyper, fördelningen mellan transportslag, och totala transportkostnader. Analysen görs med den svenska nationella godstransportmodellen Samgods och studerar två scenariotyper. I det första scenariot ersätter förarlösa lastbilar hela flottan av konventionella lastbilar. I det andra scenariot införs förarlösa lastbilar som enbart kan köra mellan logistikterminaler som ett komplement till konventionella lastbilar. Analysen visar att förarlösa lastbilar leder till en betydande ökning av efterfrågan på lastbilstransporter till följd av överflyttningfrån sjöfart och järnväg i båda scenarierna. På nationell systemnivå kan förarlösa lastbilar minska de totala kostnaderna för svenska godstransporter i storleksordningen miljarder kronor per år. Åandra sidan kan den betydande ökningen av lastbilstrafik också medföra ökade samhällsekonomiska kostnader, till exempel genom ökade koldioxidutsläpp och trängsel, vilka dock inte kvantifieras i studien. I Artikel 3 presenteras en analys av innovationssystemet för förarlösa lastbilar som bygger på en intervjustudie med aktörer involverade i utvecklingen och införandet av förarlösa lastbilar i Sverige. Resultaten indikerar att det finns flertalet gynnsamma faktorer för ett framgångsrikt införande, samtidigt som innovationssystemet i flera avseenden karakteriseras av en låg mognadsgrad och stora osäkerheter kopplade till infrastrukturfrågor, vilka affärsmodeller som kommer uppstå samt vilka aktörer som kommer gynnas eller missgynnas av utvecklingen. Resultaten från denna avhandling kan vara av intresse för beslutsfattare då de belyser potentiella nyttor och utmaningar med förarlösa lastbilar från ett transportsystemperspektiv och de indikativa systemeffekter som kvantifieras ger en fingervisning om hur ett framtida godstransportsystem med förarlösa lastbilar kan se ut. Avhandlingen belyser också viktiga utmaningar för innovationssystemet för förarlösa lastbilar vilket kan vägleda eventuella ansträngningar för att förbättra det.

Bioretention is increasingly being employed as a stormwater management tool in urban areas, with the intent of using infiltration to address both water quantity and quality concerns. However, bioretention soil media (BSM) has limited removal capacity for dissolved contaminants; hence, amendments may be justified to improve performance. In this study, the potential of five low-cost sorbents as BSM amendments – waste tire crumb rubber (WTCR), coconut coir fiber (CCF), blast furnace slag (BFS), biochar (BC) and iron coated biochar (FeBC) – were investigated for removing several classes of contaminants from simulated stormwater (SSW). The contaminated SSW contained a mixture of metals (Cr, Cd, Cu, Pb, Ni and Zn), nutrients (ammonium, nitrate, and phosphate) and PAHs (pyrene (PYR), phenanthrene (PHE), acenaphthylene (ACY) and naphthalene (NAP)). First, batch studies were used to investigate the sorption capacities, kinetics, and the effects of different water quality parameters on sorbents performance. Then, a long-term vegetated column study was conducted to investigate the performance of three amendments (CCF, WTCR, and BFS) under intermittent runoff condition considering different runoff intensities and antecedent dry periods (ADP). The long-term effects of amendments on plant health and infiltration rate of all media were also investigated. Finally, HYDRUS-1D and a cost model were used to investigate longevity and cost-effectiveness of all BSM. Batch test results revealed that among all sorbents, BC and FeBC were only effective for removing PAHs; CFF had high sorption capacity for both metals and PAHs; BFS was very effective for metals; and WTCR was effective for some of metals and PAHs. Metal removal by BFS occurred primarily via precipitation was due to the BFS mineral structure and high/alkaline pH. The effectiveness of CCF for removing both metals and PAHs was due to its lignocellulose structure and diverse functional groups. CCF could remove metals through several mechanisms including cation exchange, complexation, and electrostatic attraction, and remove PAHs through hydrophobic interaction. Biochar in this study had a highly aromatic structure with less O-containing functional groups, and PAHs were sorbed through hydrophobic pi-pi interactions. The selectivity orders of sorbents for the removal of different metals and PAHs were Cr~Cu~Pb > Ni > Cd > Zn and PYR > PHE > ACY > NAP. This selectivity was mainly caused by differences in properties of metal ions (e.g., ionic radius, hydrogen energy, etc.) and PAHs (e.g., hydrophobicity). Phosphate was removed by BFS due to its Al, Fe and Ca contents, but the other sorbents were ineffective for nutrient removal. Metals sorption capacity of sorbents was greater at higher pH, lower salinity and lower DOC; however, PAHs sorption capacity of sorbents was generally not sensitive to water quality parameters. Column experiments showed that almost all amended and non-amended BSM were able to remove > 99% of influent metals over the 7-month experiment period (except Zn in WTCR media). Cu and Cr effluent concentrations in all media (except BFS media) increased to ~ 10% of influent concentrations during heavy rainfall which was probably due to decomposition of Cu/Cr-organic matter complexes. All bioretention columns removed > 99% of PHE and PYR (higher molecular weight PAHs) regardless of rain intensity and ADP, while the performance of different media for removing the lower molecular weight PAHs (NAP and ACY) varied with the rain intensity, and removal decreased when larger storms were experimentally simulated. For nutrients, among all media, BFS-amended media had high phosphate removal capacity (> 90%). Nitrate removal in all columns was notably affected by changes in stormwater intensity and ADP, likely due to difference in degree of saturation and the potential that anoxic conditions were created, which are favorable for denitrification. All media were ineffective in ammonium removal, and ammonium production occurred throughout experiment which might be due to the lack of nitrifiers in the media. Hydraulic properties of all media were appropriate over the entire experiment. BFS-amended media had the greatest negative effect on plant health, while CCF-amended media was supportive for plants. The transport model results showed that the predicted metal breakthrough times (according to EPA criteria) for different media were 6 years for non-amended media, 7 years for WTCR media, 25 years for CCF media, and 70 years for BFS media. Modeling PAHs, nutrients and some metals (Cr and Cu) under intermittent flow conditions are complicated and other processes and models need to be investigated as future study. Finally, cost analysis results showed that among all bioretention media, CCF- and BFS-amended media with the lowest capital and maintenance costs were the most cost-effective BSM. This research will improve our understanding of BSM amendments that will improve water quality while simultaneously support bioretention system hydrologic function as well as estimating costs of bioretention systems for a long-term application. / Civil Engineering

This Master Thesis develops the challenges of travel modeling during the Olympic and Paralympic Games, more specially for the Paris Olympics in 2024. This problem as been set by IDFM (Île-de-France Mobilités), the transport organisation authority of Paris and its region, that has therefore to deal with public travel during the Olympics. A very simplified model was already in use, but is no longer sufficient. The exceptional nature of this event, considered as a mega-event, requires a precise understanding of the subject as well as a different and adaptive modeling process. Thus, this work presents a detailed methodology for public transport travel modeling in Paris and its surroundings during the Olympics. This model will become more and more refined until the end of this mega-event, in order to present results or advert the multiple stakeholders around the topic of the Olympic Games transportation (event organizers, transport operators). The two significant parts of the model are distinguished and described: the Olympic Games related trips and the background demand, which require two very different approaches. The OG demand needs several assumptions which are often in constant evolution: the versatility of the parameters is a very important point to take into account. On the other side, the background demand prediction is a significant challenge because it differs from what is usually done. Both of these parts are adapted from the principle of the four-step transportation model and reuse parts of the IDFM model, ANTONIN 3, specifically calibrated for the Île-de-France region. It is also necessary to conceive with the will to adapt as much as possible the available transport data and the tools already in operation, such as the model already in use. Suggestions for further improvements are also mentioned to refine the results until the final day which will be possible thanks to enhancements of the input assumptions over time, such as ticketing data for instance.

No description available.