The most common technique for carbon dioxide removal from gaseous streams is amine scrubbing, a proven technology in the oil and gas industries. The use of this route in coal fired power plants is not fully understood and the likelihood of solvent degradation is high. Decreased absorption efficiency, undesirable byproducts, the environmental impact of their disposal and increased process costs are the main consequences. In this study, two experimental rigs were designed and commissioned to explore the effects of gas composition and temperature on monoethanolamine degradation. Analytical procedures to detect and quantify its major thermal and oxidative degradation products were also developed. It became apparent early on that solvent degradation, under actual plant conditions, is a slow phenomenon, thus, it was decided to focus on thermal degradation. The present study uniquely enabled the absorption/desorption behaviour of thermally degraded solvents to be evaluated. The major thermal degradation products were quantified. After 14 full absorption/stripping cycles at the presence of 16% oxygen and 15% carbon dioxide, significant concentrations of nitrites and nitrates were detected in the samples. Thermal degradation at 160 oC for 8 weeks reduced monoethanolamine concentration by almost 95%, as evidenced by the chemical analysis, but the remaining solvent retained 22% of its capacity to remove carbon dioxide. Therefore, although not fully quantified, the requirement for monoethanolamine make-up may not be quite as serious as initially believed. There is some evidence to support that the rate of thermal degradation was enhanced as carbon dioxide loading increased and a 20% higher MEA loss was determined in the samples with the rich initial molar loading. A range of degradation products were quantified that correspond to those cited in the literature. 1-(2-hydroxyethyl)-2-imidazolidinone was indicated as the most stable MEA degradation product in the degraded samples at concentrations of up to 17% v/v.

This thesis examined a range of methods for sampling soil pore water to investigate the chemistry of trace elements. In particular, the study assessed whether Rhizon samplers, centrifugation, high pressure squeezing and soil suspensions in simulated pore water can be viable approaches for obtaining representative samples of equilibrated soil pore water. Results for metal solubility and speciation were interpreted in terms of both soil morphological effects on trace metal dynamics and artefacts introduced at various stages during sample preparation and handling. The main soil used in the study was an organic-rich sandy silt from a site which has served as a sewage re-processing facility for almost a century. This soil was chosen because of its importance as a long-term repository for metal-enriched sludge applied to arable land, providing a suitable medium on which to study trace metal behaviour. Pore waters were extracted and analysed for major and trace cations and anions, pH, Dissolved Inorganic Carbon (DIC) and Dissolved Organic Carbon (DOC) at two different temperatures (5 degrees Celsius and 15 degrees Celsius), in order to evaluate the extent of bacterial activity, organic decomposition and their consequences on solute composition, during pore water extractions. Speciation was estimated from analysis of pore water chemistry using two software packages (PHREEQCi and WHAM-VI). Pore waters showed different ranges of concentration between the various methods. Different mechanisms and/or chemical reactions were involved during the different extractions; a range of processes was identified, mainly dominated by metal complexation by humus acids and redox reactions. Results revealed that the soil studied was able to partially buffer the free ion activities of the metal ions in pore water with increasing dilutions, but demonstrated virtually no ability to buffer DOC. Identification of the source (i.e. location of pore space) of water extracted was also investigated using water with different isotopic composition (18O/16O). Evidence showed that centrifugation was not able to differentiate between more and less mobile water at FC conditions, rather enhancing the mixing between the two pools of water (native and labelled) by and apparent process of 'infusion'. By contrast, Rhizon samplers appeared to sample water preferentially from the more accessible pool (extra-aggregate), which proved to have a composition showing incomplete mixing with the native water. The results also suggested that mixing of the two pools was rather fast and that was almost completely attained prior to pore water extraction. The study established that the most important factors affecting pore water chemistry during extraction are the conditions to which the samples are exposed during the extraction process. For these reasons Rhizon samplers should be used as a disposable device, and are only applicable for use in high soil moisture soil contents. In contrast, they present no 'side-effects' (providing enough equilibration time) if M2+ (free ion activity) were needed as opposed to Msol (total metal concentration in pore water), as often required in environmental studies. Centrifugation is optimal for bulk solution studies, or when homogenisation represents a key experimental point; targeted studies are also possible. Soil squeezing is subject to severe limitations in the case of prolonged extractions of biologically active soils, due to the effects of anaerobism. Squeezing should only be used for 'fast' extractions of soils. Finally, batch extractions are well suited to studies on M2+ equilibria, but more studies are needed to clarify the effect of soil: solution ratio on metal and DOC solubility.

The United Kingdom utility services are facing the challenge of "mapping the underworld" over four million kilometres of buried pipes and cables (a combination of water, sewage, gas, electricity and drainage). Having accurately mapped pipes and cables increases the efficiency of street works projects, but many existing pipes and cables were only mapped relative to other topographic map features and to varying levels of accuracy. The aim of this thesis is to research various means of improving the positional accuracy of underground utilities in built-up areas through the use of Global Navigation Satellite System (GNSS), integrated with other positioning systems such as Inertial Navigation Systems (INS) and total stations. The reliability and accuracy of the integrated system is an underpinning issue and this thesis looks at testing both current and future GNSS constellations in a controlled environment at the University of Nottingham campus. GNSS integrated with an INS in the first instance, and integrated with a total-station in the second instance, are tested using a network of established points in urban canyon environments on the campus. Several, new technologies were developed by the author including: Urban Canyon GNSS Simulation (UCGS) - a GIS tool; Multiple Step Integration Technique (MSIT) - a methodology for GNSS/INS data collection and processing; and Continuous Updating Technique (CUPT) - a software for GNSS/total-station integration. The results of different simulations provide evidence that using more than one GNSS constellation will significantly increase the availability of GNSS positions in urban canyon environments. However, position availability using the criteria of 5 or more satellites with a Position Dilution Of Precision (PDOP) value of 6 or less for centimetre level is not guaranteed 100% of the time when using GNSS alone. Considering the results of the integrated GNSS/INS system, the position availability was guaranteed 100% of the time in all environments, but the accuracy is not enough to meet utility service requirements. The best results used GNSS integrated with a total-station and showed that, in this case, position availability to a centimetre level of accuracy can be guaranteed 100% of the time in all environments.

Substantial savings in operations can be achieved by reducing the amount of wastewater that must be pumped and treated. Utilities have long dealt with the infiltration and inflow (I and I) issues in their system by televising their pipes and identifying leak points, but this primarily addresses only the infiltration part of “I and I.” Inflow, which creates hydraulic issues during rain events, leads to sanitary sewer overflows and can subject the utility to fines from regulatory agencies. As a result, dealing with the inflow portion of I and I is needed. The goal of this thesis is to differentiate inflow and infiltration from baseflow and to determine the effectiveness of different methods used to reduce inflow and infiltration in sanitary sewer lines. An analysis was conducted on the benefits and cost effectiveness of different inflow/infiltration approaches (slip-lining sewer lines, stormwater manhole inserts, replacing sewer lines, smoke testing, etc.) and cost savings municipalities can expect to receive from each. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2015. / FAU Electronic Theses and Dissertations Collection

Choi Chi Yuen. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2000. / Includes bibliographical references (leaves 146-159). / Abstracts in English and Chinese. / Abstract / Acknowledgement / Contents / List of Figures / List of Tables / List of Plates / List of Appendices / Chapter Chapter 1 --- Introduction / Chapter 1.1 --- Landfilling --- p.1 / Chapter 1.1.1 --- Definition --- p.1 / Chapter 1.1.2 --- Waste decomposition process --- p.2 / Chapter 1.1.3 --- Major principles of landfill design --- p.7 / Chapter 1.1.4 --- General practices after the completion of landfill --- p.10 / Chapter 1.1.4.1 --- Surface capping --- p.10 / Chapter 1.1.4.2 --- Revegetation --- p.10 / Chapter 1.1.4.3 --- Post-closure management --- p.14 / Chapter 1.1.4.4 --- End use --- p.15 / Chapter 1.2 --- Post-closure landfill problems --- p.15 / Chapter 1.2.1 --- Subsidence and soil compaction --- p.15 / Chapter 1.2.2 --- Vegetation establishment --- p.16 / Chapter 1.2.3 --- Soil quality and thickness --- p.17 / Chapter 1.2.4 --- Adverse landfill factors --- p.22 / Chapter 1.3 --- Landfill ecology --- p.23 / Chapter 1.3.1 --- Soil-plant ecosystem on completed landfills --- p.23 / Chapter 1.3.2 --- Landfill soil fauna --- p.24 / Chapter 1.3.3 --- Landfill soil microbes --- p.25 / Chapter 1.3.4 --- Ecosystem integral development --- p.26 / Chapter 1.4 --- Succession management --- p.28 / Chapter 1.5 --- Objectives of the study --- p.32 / Chapter Chapter 2 --- Comparative Study of Landfills in Hong Kong / Chapter 2.1 --- Introduction --- p.34 / Chapter 2.2 --- Materials and Methods --- p.36 / Chapter 2.2.1 --- Site selection --- p.36 / Chapter 2.2.2 --- Soil characteristics --- p.39 / Chapter 2.2.2.1 --- Field measurement --- p.39 / Chapter 2.2.2.2 --- Soil sampling and laboratory analysis --- p.40 / Chapter 2.2.3 --- Vegetation characteristics --- p.42 / Chapter 2.2.3.1 --- Coverage of trees and understorey vegetation --- p.42 / Chapter 2.2.3.2 --- Coverage of individual plant species --- p.42 / Chapter 2.2.4 --- Calculation of representative plant score --- p.42 / Chapter 2.2.5 --- Statistical analyses --- p.44 / Chapter 2.3 --- Results and Discussion --- p.44 / Chapter 2.3.1 --- General properties of the cover soil on completed landfills --- p.44 / Chapter 2.3.2 --- Landfill categorization based on edaphic properties --- p.48 / Chapter 2.3.3 --- Vegetation coverage on completed landfills --- p.55 / Chapter 2.3.4 --- Vegetation characteristics on completed landfills --- p.59 / Chapter 2.4 --- Conclusions --- p.65 / Chapter Chapter 3 --- Vegetation Performance on Selected Landfills / Chapter 3.1 --- Introduction --- p.68 / Chapter 3.2 --- Materials and Methods --- p.70 / Chapter 3.2.1 --- Vegetation analysis --- p.70 / Chapter 3.2.2 --- Vegetation descriptions --- p.71 / Chapter 3.3 --- Results and Discussion --- p.73 / Chapter 3.3.1 --- General description of the vegetation --- p.73 / Chapter 3.3.2 --- Vegetation structure and diversity --- p.73 / Chapter 3.3.3 --- The most successful and important plant species --- p.86 / Chapter 3.3.4 --- Revegetation success --- p.91 / Chapter 3.4 --- Conclusions --- p.95 / Chapter Chapter 4 --- Diversity and Population of Soil Invertebrates on Selected Landfills / Chapter 4.1 --- Introduction --- p.99 / Chapter 4.2 --- Materials and Methods --- p.100 / Chapter 4.2.1 --- Diversities of soil and litter invertebrates --- p.100 / Chapter 4.2.1.1 --- Soil and litter sampling --- p.100 / Chapter 4.2.1.2 --- Soil animal extraction --- p.101 / Chapter 4.2.2 --- Statistical analysis --- p.101 / Chapter 4.3 --- Results and Discussion --- p.103 / Chapter 4.3.1 --- General description of the soil invertebrates --- p.103 / Chapter 4.3.2 --- Dominant soil invertebrates --- p.107 / Chapter 4.3.3 --- Soil macroarthropods --- p.109 / Chapter 4.3.4 --- Other soil invertebrates --- p.112 / Chapter 4.3.5 --- General description of litter invertebrates and its implication --- p.113 / Chapter 4.3.6 --- Diversity of the soil and litter fauna and the ecosystem development --- p.117 / Chapter 4.4 --- Conclusions --- p.119 / Chapter Chapter 5 --- Microbial Performance on Selected Landfills / Chapter 5.1 --- Introduction --- p.121 / Chapter 5.2 --- Materials and Methods --- p.123 / Chapter 5.2.1 --- Soil sampling --- p.123 / Chapter 5.2.2 --- Microbial analyses --- p.123 / Chapter 5.2.2.1 --- Plate-count methods for microbial abundance --- p.123 / Chapter 5.2.2.2 --- ATP bioluminescence assay for microbial biomass --- p.124 / Chapter 5.2.2.3 --- Dehydrogenase activity measurement for microbial activity --- p.125 / Chapter 5.2.3 --- Soil analyses --- p.125 / Chapter 5.2.4 --- Statistical analyses --- p.126 / Chapter 5.3 --- Results and Discussion --- p.126 / Chapter 5.3.1 --- The effect of soil quality on microbial population --- p.126 / Chapter 5.3.2 --- Relationship between the faunal and microbial populations --- p.128 / Chapter 5.3.3 --- Microbial diversity of cover soil of the completed landfills --- p.131 / Chapter 5.3.4 --- Microbial biomass of cover soil of the completed landfills --- p.132 / Chapter 5.3.5 --- General microbial activity of cover soil of the completed landfills --- p.137 / Chapter 5.4 --- Conclusions --- p.137 / Chapter Chapter 6 --- General Conclusions --- p.141 / References --- p.146 / Appendices

As the currently available methods for recycling of valuable metals from batteries and old electronics (commonly called eWaste) are in need of improvement, this project focuses on the development of a novel valuable metals recovery method by electrolysis in molten salts. The process proposed consists of three steps: metal oxides dissolution in borate salts, liquid-liquid interface ion transfer between the borate and chloride layer, and electrodeposition from the chloride phase. Inherent borate salts stability and its affinity to metals, coupled with the chloride salts large electrochemical window enables a stable and efficient (semi)-continuous process concept to be explored. Two electrolytic cell concepts akin to an industrial set-up were designed. The first composed of three interconnected chambers each for one of the three steps of the process, or a simpler, single-vessel solution relying on the immiscibility of the molten phases. For the needs of a laboratory scale testing the smaller, one vessel solution has been assembled. The proposed recycling method is a novel solution for the recovery of valuable metals considered and evaluated in this work; Co, Cu, Ni, and Mn, present in most Li-ion and Ni-MH batteries, but also other metals suitable for electrodeposition present in the eWaste or other metal-rich waste streams. The process proposed was designed, evaluated and resulted in a successful recovery of all of the metals considered. Novel and promising experimental data on the metal oxides dissolution in molten borate salts is reported. Boron oxide salts were assessed, with the sodium borate achieving significant metals concentrations ranging from 4-20 wt%. Metals distribution between the oxide and halide layers was evaluated, and was found to be biased towards the borate layer due to its structure resulting in high metal affinity, with the metal ions concentration in the chloride layer around 1 wt% for the evaluated salts combination. This enables the sodium borate phase to work as a buffer, feeding the dissolved metal required for the electrodeposition into the chloride layer sustaining the process. Liquid-liquid interface transfer and diffusion phenomena in the melt as well as the metal electrodeposition parameters were studied using a range of (electro)-analytical methods, validating the main steps of the proposed metal recovery process. The system was evaluated in a three-electrode set-up (WE: tungsten, CE; graphite, QRE: tungsten) and the formal redox reaction potentials were reported for the following feedstock: Co2O3 [-0.733/-1.848 V], CuO [-1.297/-2.375 V], Mn2O3 [-1.552 V] and NiO [-1.734 V] versus chlorine evolution. The recovered metals were analysed and found to form high purity (~99 %) dendritic deposits (SA/V of 950 cm-1), which also supports the assumption of a diffusion controlled process. This marks the successful outcome of this proof-of-concept process, providing a feasible, alternative valuable metals recovery method design.

The results of the degradation of glycerol in supercritical water show that conversion of pure glycerol (58 % at 550 \(^0\)C) without a catalyst can be achieved, but complete conversion of pure glycerol over Fe\(_2\)O\(_3\)+Cr\(_2\)O\(_3\) or Fe\(_3\)O\(_4\) catalysts (at 550\(^0\)C, 250 barg, <15 wt% feed concentration, 10.1 g and 4 mm catalyst particles) can be reached. Crude glycerol conversion decreases from 100 to 67 mole% and 100 to 74 mole% over the same catalysts and conditions. Hydrogen yield was as high as 61 mole% and 49 mole % when crude glycerol was gasified over Fe\(_3\)O\(_4\) and Fe\(_2\)O\(_3\)+Cr\(_2\)O\(_3\), respectively. 64 mole% of syngas was obtained with minimum 4:1 mole ratio of H\(_2\):CO. Hydrocarbon yields (69 mole% for ethylene and 22 mole% for methane) were obtained and this decreased with temperature as resulted of thermal cracking. Small amounts of char (<3.1 wt%) and carbon deposition on the catalyst surface and inside the reactor wall was observed. Prolonged exposure of Fe\(_2\)O\(_3\)+Cr\(_2\)O\(_3\) to 172 h on-stream under supercritical conditions resulted in fragmentation of the surface from metal sintering, which reduced activity for H\(_2\) production. 42 mole% of hydrogen was obtained from 2 wt% digestate gasification at the same conditions.

Current food production and consumption practices are depleting natural resources and polluting ecosystems at a rate that is unsustainable and are one of the main causes of anthropogenic climate change. If this trend does not change, externalities of food production will be exacerbated in future decades due to population growth and increasing living standards. A shift towards low impact diets has been proposed as part of the solution. The public food sector offers tremendous potential for influencing such a shift; however currently in the UK this potential is only partially exploited as national guidelines for public food procurement avoid promoting the adoption of low impact menus. This doctoral research aims at addressing this shortfall by creating a procedure for the design of low impact primary school menus. This is informed by a life-cycle based tool (the Environmental Assessment Tool of School meals, EATS) that enables catering companies and local authorities to self-assess the environmental impact of a meal in terms of its carbon and water footprint, with the purpose of identifying hotspot meals and comparing alternatives in the design of new menus. The data underlying EATS includes the results of a meta-analysis of the existing literature on the carbon footprint of 110 food products commonly used in the preparation of primary school meals in the UK. To validate EATS, a statistical analysis of the underlying data was performed, feedback from its potential users was collected, three case study analyses were developed, and the results provided were compared with existing studies.

This study examined the load-settlement characteristics and mechanism of failure of a footing-type foundation resting on untreated soil, soil treated with an ordinary stone column (OSC), and soil treated with an encased stone column (ESC) into artificial loess deposits subjected to inundation. The investigation was carried out by means of conventional geotechnical laboratory work and the electrical resistivity tomography method. In addition, an analytical solution using a MATLAB script was presented to determine the load carrying capacity of the reinforced foundation and to validate the experimental results. Outcomes of the physical model demonstrated the efficiency of using an encased stone column over the ordinary stone column and the untreated collapsible soil. Results of the resistivity tomography system offered a valuable window into the soil-column interface. The soil conductivity was very sensitive to load and moisture variations during collapse. The analytical model illustrated that the enhancement in the ultimate bearing capacity of the reinforced column is influenced in proportion to variations in both the degree of saturation and matric suction. It increases with increasing the tensile strength of the geotextile and the angle of internal shear resistance of the fill material. However, it decreases when the diameter of the column expands.

Indoor microenvironments can have a relevant contribution towards the total exposure to pollutants. The biomarkers of exposure and effect were analysed in general population, to evaluate the impact of VOCs, PAHs and tobacco smoke exposure in everyday life. We designed a model for toxicological studies, as proof of concept for future studies. We analysed airborne personal exposure to air pollutants, the urinary and oxidative stress biomarkers of three exposure level groups in a non-smoking population from Birmingham, UK, a subset with high exposures to tobacco smoke, and a subset of schoolchildren in Saudi Arabia, living in high pollution areas. A significant correlation was observed between low concentration urinary cotinine and urinary VOCs. Urinary VOCs were found suitable for exposure assessment of general population, although the correlations with oxidative stress biomarkers were weak. No significant correlation between urinary PAHs and oxidative stress was observed in schoolchildren from Saudi Arabia, although certain areas showed a significant increase in urinary PAHs and oxidative stress biomarker. The cell exposure system was designed and tested so it could be applied in future toxicological studies. The observed ROS generation and DNA damage in the cells after exposure, proved the validity of the model for benzene exposure.