School of Water, Energy and Environment (SWEE)
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Item Open Access Adapting water management in India to climate change: institutions, networks and barriers.(2017-05) Azhoni, Adani; Holman, Ian P.; Jude, SimonClimate change is experienced most through the medium of water. The ability of water institutions and the factors that enable or hinder them to purposefully adapt to the new and additional challenges brought by climate change require better understanding. Factors that influence their perception of climate change impacts and initiatives being taken for adaptation are shaped by various enabling factors and barriers through the interaction with both governmental and non-governmental institutions across administrative scales. Better understanding of these adaptation enablers and barriers is essential for devising adaptation strategies. This research aims to identify and expound the characteristics that enable or hinder institutions to adapt for water management, and hence, it evaluates the involvement of key governmental and non-governmental institutions in India and the inter-institutional networks between them. It surveyed webpages and online documents of sixty Union Government institutions and interviewed representatives from twenty-six governmental, non-governmental, research and academic institutions operating at the national level and another twenty-six institutions operating within the State of Himachal Pradesh in India to assess the characteristics that enable or hinder adaptation. While the online projection of institutional involvement and interaction among key Union Government institutions on climate change and water indicate a more centralized network pointing to Planning Commission and Ministry of Environment and Forest, the interview responses indicated a more distributed network with both Ministries of Water Resources and Environment and Forest recognized as key institutions thereby indicating a potential variation in perception of who is in-charge. Moreover, online documents show institutions that are involved in water have less mention of climate change compared to Union Government ministries involved in less climate-sensitive sectors indicating that impacts of climate change on water are potentially ignored. While it is evident that research and consulting institutions engaging with both national and state level institutions play a key role in enabling adaptation, various barriers pertaining to data and information accessibility, inadequacy of resources and implementation gaps exist particularly due to inter-institutional network fragmentations. Although barriers identified in this study bear resemblance to barriers identified by other researchers in other contexts, this research shows similar barriers can emerge from different underlying causes and are highly interconnected; thereby indicating the need for addressing adaptation barriers collectively as a wider governance issue. Since many of the adaptation barriers emerge from wider governance challenges and are related to larger developmental issues, the findings have important policy implications. Among the various issues that the government needs to address is improving the inter-institutional networks between water institutions so that information dissemination, sharing of learning experiences and data accessibility is improved and prescriptive legislations are seen to be inadequate in this regard. Restructuring the way officials in government water institutions are recruited and deployed is suggested as a potential solution for improving the inter-institutional networks. The research elucidates that inter-institutional networks and transboundary institutions are two pillars that supports adaptation and also bridges the gap between adaptive capacity and adaptation manifestation that enable water institutions to cross the chasm of adaptation barriers. Thus the thesis presents an important analysis of key characteristics that enable or hinder water management institutions to adapt to climate change which have been so far under acknowledged by other studies through the analysis of the state of climate change adaptation in India. Therefore, this study provides valuable insights for developing countries, particularly, facing similar challenges of adapting water management for climate change.Item Open Access Advanced control of a multi-sourced multi-level source inverter system for high performance electric vehicles.(2016-06) Bendyk, Maciej Szymon; Luk, Patrick Chi-KwongAt present, electric vehicles are getting very popular and there is a high demand for related technologies. Therefore, car manufacturers are looking for cost- effective solutions to improve the efficiency and performance of drive trains. One of the biggest challenges is to create an efficient, reliable and robust system architecture integrated with energy management systems to maximize its performance. Thus, in the last decade technologies started evolving towards use of higher voltage levels with multiple energy sources, which involve complex control and power electronics capable of performing sophisticated functions. In the quest for a new electric drive-train technology, a system architecture together with power and energy management has been identified as a key area of research. This work investigates problems related to the complexity of energy management for power-limited energy sources to improve performance in the whole operation envelope. The widely accepted solution of using multiple energy storage systems is discussed and found to relate to more complicated and expensive power electronic hardware. Furthermore, to achieve high power with reasonable efficiency it is necessary to use high voltage, which is difficult to attain. This work proposes an electrical system with integrated motor control and energy flow management between multiple electric sources with the aim to increase the power capability of an electric drive train. To reach good performance and high efficiency the multilevel, cascaded Voltage Source Inverter with multiple sources is introduced to provide instantaneous proportional power split and to boost voltage for the electric motor at the same time. Whilst there are existing examples of multilevel inverters with electric motor drives, none of them has successfully found their way to mainstream vehicles due to the intricacy and many unresolved technical challenges. This thesis contributes to the field of power electronics in the following areas. Firstly a detailed mathematical analysis of hybrid cascade multilevel inverter with variable voltage ratio between sources has been performed to find its the sources. Secondly, based on the derived equations a new multilevel inverter control and modulation strategy to increase the transient power capability by distributing power between the battery and ultracapacitors has been developed. The method has been validated first through a simulated model in Matlab/Simulink and subsequently by experimental work on a specifically designed and built hardware platform. The results showed that the proposed architecture with modest increase in complexity can markedly improve the system’s transient power capability, and contribute to higher maximum output voltage availability and at the same time minimize Total Harmonic Distortions and switching losses.Item Open Access Advanced structural health monitoring strategies for condition-based maintenance planning of offshore wind turbine support structures(2019-04) Martinez Luengo, Maria; Shafiee, Mahmood; Kolios, Athanasios; Engineering and Physical Sciences (EPSRC)Condition-based maintenance strategies need to be adopted as distance-to-shore and water depth increase in the offshore wind industry. The aim of the research presented herein is to develop advance structural health monitoring strategies that enhance the condition-based maintenance of offshore wind turbine support structures. The focus is on the selection of technologies, the implementation process, the analysis of the asset’s structural response under complex loading, the economic justification for structural health monitoring implementation and the effective structural health monitoring data analysis. Research activities consist of the provision of a comprehensive study for structural health monitoring technologies’ utilisation in the offshore wind industry. This is followed by parametric structural modelling, simulation and validation of an operational offshore wind turbine tower, support structure and soil-structure interaction, using commercial software. The evaluation of the asset’s response under complex loading subject to design changes and failure mechanisms is also undertaken. A combination of existing and newly developed methodologies is deployed for the effective data management of structural health monitoring systems and validated with industrial data for the case of strain monitoring. These include unsupervised learning algorithms (neural networks), deterministic and probabilistic methods for noise cleansing and missing data imputation. Guidelines for the structural health monitoring implementation from design stage of a wind farm are proposed and applied to a baseline scenario. This is utilised to assess the economic impact that structural health monitoring has in the lifecycle of the assets. The achieved results show that the implementation of structural health monitoring in offshore wind turbine following the Statistical Pattern Recognition paradigm and the proposed guidelines has the potential to reduce the Operational Expenditure. This reduction is much greater than the cost associated with the implementation of these systems. Monitoring from the commissioning of the assets is crucial for the system’s calibration and establishing thresholds. The developed noise cleansing and missing data imputation methodologies can successfully be employed together to produce more complete low-disturbed datasets.Item Open Access Aeroterrestrial and freshwater microalgae biofilms: deposition and growth in aqueous and non-aqueous systems.(2016-12) Ledwoch, Katarzyna; Villa, Raffaella; Jefferson, BruceNon-suspended microalgal cultivation methods have gained an interest over the last decade. In contrast to traditional cultivation systems, where microalgae are grown in highly diluted suspensions, microalgae grow concentrated in biofilms over a particular substrate. Growth in biofilms gives higher biomass concentrations of end products and decreases overall water and energy consumption. However, there are research gaps in the field of biofilm formation and growth. The studies on material and strain properties and their effects on microbial attachment are very limited. So far, a small number of strains and materials have been tested, leading to many contradictory conclusions. In this thesis the primary colonisation of 36 material-strain pairings was tested and related to topographical and physicochemical properties of substrates. Experimental data was also confronted against properties of microalgal strains. Further microalgal biofilm development in aerial conditions, and its relation to substrate properties, was analysed for the first time. To address some of the sustainability issues associated with microalgal cultivation, a novel Humid Biofilm-Based Reactor (HBBR) was also proposed. This novel method focused on growing microalgae in a humid atmosphere enriched with nutrients. The natural phenomenon of biofilm development in aerial humid conditions was a working principle of the system, resulting in higher biomass concentrations than in other non-suspended reactors proposed so far. Using mist instead of a liquid medium significantly minimised the water consumption. No presence of a liquid medium in the reactor enabled easier maintenance of the system and improved light distribution. Growth trial in this novel reactor and its comparison to reference systems showed that HBBR was a promising way of culturing microalgae with higher growth rates, lower water and nutrient consumption, more effective light distribution and easier maintenance of the system.Item Open Access Agronomy and economics of two novel energy crops: Sida Hermaphrodita (L.) Rusby and Silphium Perfoilatum L.(2021-05) Cumplido-Marin, Laura; Graves, Anil R.; Burgess, Paul J.The PhD project of title “Agronomy and Economics of two novel energy crops: Sida hermaphrodita (L.) Rusby and Silphium perfoliatum L.” was first conceptualised within the international project SidaTim. The main aim of the PhD was to reduce the uncertainty associated with the adoption of Sida hermaphrodita (L.) Rusby and Silphium perfoliatum L., through data gathering and evaluating their agronomic, economic and environmental performance. The main objectives of the PhD were: to review all available information and publications regarding the cultivation and energy production of the two species; to assess their agronomic performance in the UK; to examine the impact of their establishment on soil carbon; to determine their profitability against other potential crops across a European gradient; and to evaluate the greenhouse gas emissions associated with their cultivation. The novelty of the research lies on the establishment and assessment of two novel bioenergy crops in the UK compared across a range of climatic conditions, addressing the knowledge gaps regarding reliability and availability of information and assessment of their agronomic, economic and environmental performance. The first year of the project was dedicated to background research, collecting and processing the first set of soil analyses, producing all Silphium perfoliatum (L.) seedlings from seed, importing Sida hermaphrodita (L.) Rusby seeds from Germany, and in 2017 establishing an experimental site in Silsoe, Bedfordshire, UK. During the first three years,the mean maximum height of Sida hermaphrodita (L.) Rusby originated from seedlings was 198 cm and the maximum stem diameters were 14-18 mm. The mean maximum height of Silphium perfoliatum (L.) was 158 cm over three years and the maximum stem diameters were 14-16 mm. As opposed to the expected increase in maximum heights and diameters with time until plantation maturity, an overall reduction in maximum heights and diameters was recorded with time for Sida hermaphrodita (L.) Rusby, whilst only maximum diameters of Silphium perfoliatum (L.) decreased with time. Each year from February 2018, a winter harvest to measure the solid biomass production of Sida hermaphrodita (L.) Rusby and a summer harvest to measure the green biomass production of both Sida hermaphrodita (L.) Rusby and Silphium perfoliatum L. were carried out until September 2020. Mean dry biomass yields of Sida hermaphrodita (L.) Rusby plants grown from transplants for solid fuel for combustion were 1.7, 5.4, and 3.7 t DM ha⁻¹ in 2018, 2019, and 2020 respectively. Green biomass yields of Sida hermaphrodita (L.) Rusby for anaerobic digestion were on average 10.8, 8.1, 6.0 t DM ha⁻¹ in 2018, 2019, and 2020 respectively. The recorded declines in harvested biomass from Sida hermaphrodita (L.) Rusby are attributed to the combined effect of plant mortality, management and fertilisation practices. The corresponding mean green biomass yields of Silphium perfoliatum L. for anaerobic digestion were 4.6, 6.7, 8.9 t DM ha⁻¹ in 2018, 2019, and 2020. The second and third year focussed on objectives three and four, as well as collecting and processing the second set of soil analyses, data analysis, and writing up. The bulk density of the soil across 0-5 cm and 10-15 cm changed from 1.4-1.7 g cm³ prior to cultivation in 2017, to a uniform 1.4 g cm³ in 2020. The concentration of soil organic carbon at 0-5 cm decreased from 2.58% in 2017 to 1.85% in 2020, whereas at 10-15 cm, it increased from 1.86% to 2.12% over the three years. Overall, the mean soil organic carbon stocks (0-15 cm) declined from 65.0-67.6 t C ha⁻¹ in 2017 in 55.2-58.3 t C ha⁻¹ in 2020. The profitability of Sida hermaphrodita (L.) Rusby and Silphium perfoliatum (L.) was predicted over a rotation of 16 years and compared to that of an arable rotation and two other energy crops for the particular case of the UK and three other European countries. The calculated net present value (NPV) of Sida hermaphrodita (L.) Rusby was -1,591 £ ha⁻¹ without subsidies and 1,075 £ ha⁻¹ with subsidies; the corresponding net present values for Silphium perfoliatum (L.) were 3,031 £ ha⁻¹ and 5,607 £ ha⁻¹ . The study also calculated how much prices and costs would need to change for the NPV of the two crops to match the NPV of the most profitable energy crop or the arable rotation. Using an Excel model developed based on the IPCC guidelines, the greenhouse gas emissions for Sida hermaphrodita (L.) Rusby and Silphium perfoliatum (L.) production were calculated for a 16-year period. On a per annum basis, overall greenhouse gas emissions were estimated respectively at 4.2, 0.3, 2.2, -4.0 and -0.6 t CO2 eq ha⁻¹ for the arable rotation, short rotation coppice, Miscanthus, Sida hermaphrodita (L.) Rusby and Silphium perfoliatum (L.) systems. The environmental assessment demonstrated that cultivating Sida hermaphrodita (L.) Rusby and Silphium perfoliatum (L.) could potentially contribute to reducing greenhouse gas emissions.Item Open Access Ammonium and phosphorus removal and recovery from wastewater through the ion exchange process.(2020-07) Guida, Samuela; Soares, Ana; Jefferson, BruceChallenges to implement circular economy principles in the wastewater cycle are connected to the need of reducing nutrients (ammonium as NH₄⁺-N, and phosphorus as PO₄-P) in treated effluent whilst enabling their recovery in an environmentally sustainable way. Conventional biology-based technologies fail to address these challenges by having high greenhouse gases footprint and offering limited possibilities for nutrient recovery. The aim of this work was to underline the mechanisms of removal and recovery of NH₄⁺-N and PO₄-P from wastewater through the ion exchange (IEX) process in order to optimise the removal efficiency and maximise the recovery from IEX regenerant brines (sodium hydroxide and potassium chloride), when working at demonstration scale over an extended period of time. The IEX process was tested in a 10 m³/day demonstration plant for 2.5 years using Zeolite-N and a hybrid anion exchanger (HAIX) for the removal of NH₄⁺-N and PO₄-P at empty bed contact times of 10 and 5 min, respectively. The operation at demonstration scale confirmed the resilience and consistency of the IEX process and the possibility to maintain high effluent quality (<0.3 mg PO₄-P/L and <1 mg NH₄⁺-N/L) despite changes in influent concentration (i.e. <0.006-26 mg NH₄⁺-N/L) and extended operational period (up to 63 consecutive adsorption/regeneration cycles with HAIX). Additionally, the regenerant brines were reused multiple times and nutrients could be recovered as high purity ammonium sulphate and hydroxyapatite using a hollow fibre membrane contactor for ammonium recovery and simple precipitation with calcium hydroxide and filtration for phosphorus recovery. The results obtained from this work additionally highlighted the need of an automated system to start the regeneration when the desired effluent quality is reached, the need of a nearly solids-free influent and high mechanical strength media to avoid media packing and losses. This work significantly moved the IEX process higher in the technology readiness level (from level 5 to level 7) for mainstream wastewater treatment with the advantages of simple operation, consistency, resilience and lower environmental impact (-25% cumulative energy demand, - 66% global warming potential, -62% marine eutrophication potential) compared to traditional biological processes.Item Open Access Anaerobic membrane bioreactors in upflow anaerobic sludge blanket configuration for energy neutral sewage treatment.(2018-03) Wang, Kanming; McAdam, Ewan; Soares, AnaAnaerobic membrane bioreactors (AnMBRs) are emerging as a promising technology to offer the prospect to achieve energy neutral sewage treatment. The key challenges limiting full-scale application of AnMBR for municipal wastewater treatment are high operational cost of energy demand for fouling control and high capital cost of membrane investments. This thesis explores a novel pseudo dead-end gas sparging regime for membrane fouling control, enabling a high sustainable flux (15 L m ¯² h¯¹) with low energy demand (0.14 kWh m⁻³ ) in upflow anaerobic sludge blanket (UASB) configured AnMBR, sufficient to achieve energy neutral sewage treatment. However, this strategy is only possible within low solids environment, emphasising the importance of solids management in the UASB reactor. Solids accumulated in the sludge blanket enhances UASB treatment efficiency during the steady-state operation, indicating to control the sludge blanket at a threshold between the sludge blanket development and steady-state period. The granular inoculum has good stability which exerts a positive influence on reactor stability and sustained permeability, whilst the flocculent inoculum enables to deliver similar sustained membrane operation provided the sludge blanket is controlled. Low temperatures (average temperature of 10 °C) cause the instability of UASB reactor especially for the one with flocculent inoculum biomass. It is therefore proposed to keep relatively high upflow velocity (Vup) of 0.8-0.9 m h⁻¹ in the UASB reactor for granular AnMBR to promote the stratification of particular and granular material, whilst reducing Vup to 0.4 m h⁻¹ for flocculent AnMBR to minimise solids washout and sustain membrane operation at low temperatures. The potential for permeability recovery following peak flow (diurnal peaks and storm water flows) has been investigated and evidenced, suggesting that membrane surface area for AnMBR can be specified based on average flow, providing a considerable (67 %) capital cost reduction compared with the design based on peak flows (three times of average flow). Importantly, this thesis promotes UASB configured AnMBR as a highly reliable and more economically viable technology, facilitating to achieve the energy neutral sewage treatment at ambient temperature.Item Open Access Application of organic amendments to restore soil health and productivity of a degraded soil.(2017-04) Unagwu, Benedict Onyebuchi; Simmons, Robert W.; Rickson, R. Jane;Organic amendments (OAs) have the capacity to enhance physical, chemical, biological soil quality indicators (SQIs) and to improve soil productivity. This study investigated the effects of different OAs (Mushroom Compost, MC; PAS-100 compost, PAS; Anaerobic Digestate Solid Waste, AD_SW; and Poultry Manure, PM), applied at 10 t ha⁻¹ and 30 t ha⁻¹ with or without inorganic fertilizer (applied at 50% of the RB209 recommended rates for maize) on key SQIs, soil health and plant performance on a degraded sandy loam soil. The treatments were laid out in a greenhouse using a completely randomized design and replicated four times. The soil and OAs were thoroughly mixed and incubated for two weeks. Thereafter, composite 3-point soil samples were taken from each treatment replicate for post-incubation (POI) soil analysis. Maize (Zea mays, Severus variety), was used to assess the impact of the OAs on plant performance. Plant height, number of plant leaves and stem diameter were measured weekly. Post-harvest (POH) composite 3-point soil samples were again taken for soil analysis. The data generated from POI and POH laboratory analyses and plant measurements were subjected to analysis of variance (ANOVA) followed by post-hoc Fisher LSD analysis at 5% probability level. At POI, the OAs had 22-44.5% higher water holding capacity [WHC], increased porosity and reduced bulk density [BD] as compared with the un-amended control treatment (CNF). The results indicate that 1% increase in soil organic matter (SOM) increased the Available Water Content (AWC) by 5.31 g g⁻¹ while reducing the BD by 1 g cm⁻¹ and increasing the soil Water Content at Field Capacity (WCFC) by 36.5 g g⁻¹ . The Olsen-P, Available-K, Available-Mg, Total-N, and microbial biomass C [MBC] associated with the OA treatments were significantly higher as compared with CNF treatment. At POH, across application rates, OA treatments with or without inorganic fertilizer addition had >15% higher (p <0.05) WHC [WCFC], 40% higher porosity and 55% lower BD as compared with CNF treatment. For both POI and POH, higher rates (30 t ha⁻¹ ) of OAs with or without inorganic fertilizer addition had higher (p <0.05) effects on the water release characteristics [WCFC, EAW, AWC] than lower (10 t ha⁻¹ ) rates of OAs. At POH, across application rates, the OA treatments increased the Olsen-P, SOM, Total-C, and TOC by over 37, 23, 75 and 81%, respectively, relative to CNF. Across application rates with or without inorganic fertilizer addition, the OA treatments did not significantly affect the CEC as compared with CNF. The OAs increased the P, K and Mg indices relative to the CNF which increased with increase in OA application rates. Further, the OA treatments increased the MBC by 72-95% (p <0.05) and reduced microbial stress by over 30% relative to CNF. Without inorganic fertilizer addition, the OA treatments increased the above ground and below ground plant biomass (AGDB and BGDB) by 24-65% and 38-88% respectively, compared with the CNF treatment except for the PAS treatments. The OAs had 100% increases in cob yield as compared with CNF, except for PAS1NF/2NF and AD_SW1NF treatments. Inorganic fertilizer addition had marked effects on plant performance, particularly when combined with the PAS OA. The study concludes that application of OAs has the potential to improve soil health and productivity of a degraded sandy loam soil. Long term effects of these OAs merit further detailed exploration.Item Open Access Aspirational toilet user experiences: translating latent user needs into aspirational user experiences.(2018-01) Larsson, Jake; Williams, Leon; Rose, TimWhat makes a product user experience aspirational? What do people truly want from their products? The aim of this research is to assess the implementation of latent needs to design an innovative aspirational product user experience. The thesis details reflective action-based research on the study of the design of an aspirational toilet user experience; a taboo subject that has little to no aspiration attributed to it. Toilets have not changed in the past 200 years and arguably the user experience is not considered aspirational. The reflections on an admittedly extreme case could in turn have implications for the other practitioners. Latent needs were elicited from 77 households in Kumasi Ghana to understand the motivations for acquiring a toilet while latent needs of the user experience were gathered from hackers online. The results suggest that the negative ‘shut away’ nature of a toilet means people do not attribute value to them while there is a universal fear of the invisibility of disease. The study resulted in the construction of a wellbeing monitoring toilet prototype that would change the meaning people attribute to toilets while beginning to satisfy the fear of disease. A final test was arranged where the improved user experience is shown to be more valuable and aspirational to users by questionnaire because the new concept affords new meaning beyond the utility that toilets currently provide. The reflections on the case study suggest that when implementing latent needs in the design of an aspirational product user experience, it is worth considering that what users say is not what they do and meaning is a dimension of innovation that is as important as technology.Item Open Access Assesment of crack arrest behaviour in modern structural steels(2021-03) Taylor, Jessica; Mehmanparast, Ali; Farrahi, Gholam HosseinIt is vital to prevent brittle cracks in large structures. This is particularly important for a number of industry sectors including offshore wind, Oil & Gas, and shipbuilding where structural failure risks loss of human life and loss of expensive assets. Wide-plate test methods allow for direct measurement of the crack arrest toughness but this kind of testing is incredibly expensive. Therefore, there is a need for cheaper and simpler test methods which are able to measure a material’s brittle crack arrest toughness. Some modern steels exhibit high Charpy energy – i.e. high initiation fracture toughness, but poor resistance to crack propagation – i.e. low crack arrest toughness. The correlation between initiation and arrest toughness measured through small-scale testing is investigated in five different steels, which include S355 structural steel (with two different thicknesses), X65 pipeline steel, two high strength reactor pressure vessel steels and EH47 shipbuilding steel. In this work, Compact Crack Arrest (CCA) testing, which is standardised in ASTM E1221, has been successfully used to measure the crack arrest toughness of thick sections of EH47 shipbuilding steel. A wide range of supplementary tests were carried out, including instrumented Charpy, drop weight Pellini, fracture toughness, tensile testing, and microscopy. Small scale mechanical tests were used to characterise the materials’ properties and the results were compared to the materials’ microstructures. The results presented in this study have been discussed in terms of the effectiveness of the CCA test method and small-scale test methods for measurement of brittle crack arrest toughness and integrity assessment of large-scale structures.Item Open Access Assessing the value of fertilisers derived from container-based sanitation systems(2018-02) Moya Diaz-Aguado, Berta; Parker, Alison; Sakrabani, RubenIt is estimated that 61% of the world population lacks access to safely managed sanitation and that in low-income countries (LICs) only 6.7% of the population is connected to a sewerage network. Container-based sanitation (CBS) systems have shown great potential for increasing access to sanitation in densely populated urban slums given that they do not require permanent infrastructures. Resource recovery is usually an essential part of CBS systems to provide sustainable faecal sludge management. Transforming human excreta into fertilisers creates value from faecal sludge while producing an organic soil amendment, addressing both sanitation and soil fertility challenges. Soil amendments made from organic residues are however known to be difficult to market profitably. This thesis therefore investigated the properties of human excreta derived fertilisers (HEDF) and the opportunities and challenges to their commercialisation in LIC. Nutrient characterisation of composts, anaerobic digestate and vermicompost from two CBS ventures showed significant differences in nutrient content between these three HEDF types. Pathogen and heavy metal analyses demonstrated that there is no pollution threat from HEDF when produced according toWHO guidelines. Field and glasshouse crop trials demonstrated the positive effect HEDF can have on crops and soil health. These benefits however do not currently translate into their commercial value. A case study approach was used to identify barriers and enabling conditions faced by two CBS organisations that successfully produce and sell HEDF. The low market value of compost prevented both organisations from recovering treatment costs from HEDF sales. One major barrier to wider adoption of HEDF use was the lack of regulations or certifications specific to this type of fertiliser. Perception challenges exist because of the potentially harmful components human excreta contain such as pathogens and heavy metals. It is therefore essential to create a way of proving or guaranteeing the quality and safety of HEDF products. The value of qualityassuring schemes for HEDF became evident when applying the Biosolids Assurance Scheme from the UK to HEDF, which helped identify a contamination issue in one of the treatment sites considered.Item Open Access Biological treatment of coke making wastewater.(2017-04) Raper, Eleanor; Soares, Ana; Stephenson, TomProduction of coke for steel manufacturing produces a wastewater containing total nitrogen (TN) (up to 600 mg/L) alongside toxic compounds phenol (60 - 400 mg/L), thiocyanate (SCN-) (100 - 400 mg/L), polycyclic aromatic hydrocarbons (PAHs) (Ʃ6PAHs:179±35 µg/L) and trace metals. Emission limits introduced by the Industrial Emissions Directive (IED) in 2016 require treated coke effluent to contain <50 mg/L TN, <4 mg/L SCN-, <0.5 mg/L phenol and <50 µg/L Ʃ6PAHs which cannot be consistently met by the conventional activated sludge process (ASP). Treatment process modifications were investigated to ensure compliance. Activated carbon addition to the ASP (400 mg/L) increased Ʃ6PAHs removal by 20% enabling emission compliance whilst increasing nickel, chromium and cadmium removal. The addition of 0.5 g/L of a commercial bioaugmentation product increased dissolved Ʃ6PAHs removal by 51%. Biostimulation (addition of micronutrients/alkalinity) enabled SCN-and phenol emission compliance. Survival of supplemented exogenous bacteria in a simulated river water discharge was investigated for the first time showing limited survivability. Thiocyanate degradation mechanisms were poorly understood but were important to ascertain, especially as SCN-degradation produces ammonia increasing TN loading. Control of influent ammonia and phenol concentration was important enabling SCN-degradation under anoxic and aerobic conditions. Deoxyribonucleic acid sequencing of the mixed culture identified a new species of Thiobacillus which had metabolic similarities to T. thioparus and T. denitrificans. Nitrification was limited (41%) confirming the importance of intrinsic alkalinity availability in the wastewater, however, sodium carbonate addition (300 mg/L as CaCO₃) increased efficiencies to 96%. An anoxic-aerobic ASP was investigated for TN removal enabling an effluent TN <50 mg/L when the soluble chemical oxygen demand (sCOD):TN ratio was maintained above 5.7. Acetic acid was identified as a suitable source of carbon addition to maintain this ratio. An anoxic-aerobic ASP combined with AC and bioaugmentation can ensure compliance with the IED.Item Unknown Blending and spray atomization modelling for gasoline-ethanol fuels.(2017-04) Etebu, Ongoebi Maureen Orubide; Sher, IlaiTo achieve the ever stringent ls of low emission and to further improve the fuel economy, a much greater control of atomization and spray processes is required in the atomizer design of spray systems. In order to achieve this l, modeling of atomization characteristics of gasoline-ethanol fuel blends, fuel breakup models and correlations between flow patterns and droplet characteristics were adopted using OpenFOAM Computational Fluid Dynamics (CFD) model for direct gasoline injector using a simple mesh structure at constant volume. The Rosin Rammler distribution model was used to generate the number of spray particles injected into the cylinder. The spray modeling and atomization involved blob sheet model and KH-RT model while the numerical technique for simulating atomization process by CFD included the use of governing equations such as Eulerian for gas phase, lagrangian for disperse phase and turbulence modeling. The evaluation of the effect of fuel blends, injection pressure, and ambient gas pressure and spray cone angle on the axial spray tip penetration, spray width, and overall Sauter Mean Diameter (SMD) were carried out. The SMD was discovered to be affected by varying the degree of injection cone angle. The spray tip penetration lengths were larger for higher injection cone angles while higher penetration lengths were obtained at higher injection pressures. One salient conclusion drawn from the modeling is that as the number of particle increased, the density of clusters became smaller.Item Unknown The Capability of Design in Government(2020-03) Geraghty, Rhonda Nadine; Longhurst, Philip; Encinas-Oropesa, AdrianaThis research increases understanding of the scope and potential of design as resource in the context of government. Currently, there is limited knowledge and use of tangible and intangible dimensions of design in government and its potential remains unrealized. This despite designs established history of use, evidence to support its economic, social, environmental, and political value and encouragement from national and international bodies. What design is and its capacity to contribute in government is explored in this research. Accomplished through seven phases of investigations, the design-in- government context is first established and then explored followed by an examination of what design is and does within this context. A mixed methods approach was employed involving a critical assessment of both theoretical and empirical insights, including a scoping review, a focused review of literature, interviews with practitioners and primary and secondary observations of the design-in-government phenomena in practice. Interactions with stakeholders, academia and industry at international engagements informed the research process and evaluated study results incrementally over a 6-year period from 2013-2019. Results reveal a dimensional and holistic perspective of design as capability in operation within a dynamic design-in-government system. Here the potential exists for all facets of design to impact all areas of government simultaneously. The establishment of the design-in-government conceptual framework and definition of design for this context are also significant outcomes from this study. Together they constitute constructs that contribute to the furtherance of the novel field of research and practice with implications for design education and the evolving design profession. Finally, the distinctive scoping review process from this research contributes to the theoretical advancement of the methodology.Item Open Access Carbon dioxide storage in the UK southern north sea: experimental and numerical analysis(2018-10) Aminu, Mohammed Dahiru; Manovic, Vasilije; Kolios, AthanasiosThis thesis contributes to the significant portfolio of research on carbon capture and storage (CCS) in general, and the potential for CO₂ storage with impurities within the UK Southern North Sea (UKSNS) to meet the global greenhouse gas emission reduction targets. First, this thesis extensively reviews the current developments in carbon dioxide storage, highlighting major options for CO₂ sequestration, storage site evaluation criteria, behaviour of CO₂ in the reservoir, methodologies for estimating storage capacity, appraisal of the major storage projects, and a projection of the future outlook for CO₂ storage. The review draws attention to the fact that although a high-quality knowledge base has been developed through CCS research, the main hinderance to CO₂ storage deployment is associated with public acceptability of the technology. Second, this thesis involves laboratory experimental investigation of the effect of impure CO₂ on reservoir grain size distributions and permeability using rock samples from the Bunter saline aquifer. The thesis shows that the presence of impurities in the CO₂ stream can affect the grain size distribution and fluid transmissivity. Third, this thesis uses numerical modelling to evaluate the effect of impure CO₂ on reservoir performance with a case study from the Bunter saline aquifer. The results show that depending on the impurities present in the CO₂ stream, the limits of stability during storage operations in saline aquifer varies, however, the variation does not affect reservoir performance negatively during long-term injection and storage.Item Open Access CFD study of a bidirectional synthetic jet as an aerodynamic flow control device.(2018-03) Fisher Fernandez, Jaime Rodrigo; Nishino, TakafumiControl of the separation and reattachment of the boundary layer has been the focus of research for a wide range of engineering applications, and it is known that a synthetic jet can be used as an active flow control device for such issues. This work presents a numerical analysis of the potential benefits of changing the inflow and outflow directions of a synthetic jet separately. The basic concept of this new flow control approach, named Bi-Directional synthetic jet (BDSJ), is to induce the Coanda effect due to the jet outflow directed downstream, and change accordingly the inflow direction for an efficient and directed suction of the boundary layer. A widely-used reference case (so-called NASA 2-D Hump) is used to validate the numerical model and to compare results. Three well known Reynolds-averaged Navier-Stokes (RANS) turbulence models are employed and they all show similar trends. Eleven different angles are tested for the inflow and outflow directions of the synthetic jet; the most effective configuration is then compared with the classical synthetic jet and Directed synthetic jet. It is shown that the best BDSJ configuration results in a shorter separation bubble length over the hump, suggesting the potential of BDSJ as a future active flow control device. This work also attempts to answer the question; "How a Bi-directional synthetic jet, influences the aerodynamic coefficients on a aerofoil". Simulations are carried out on an NACA 23012 at a Reynolds number of Re =2.19 • 10⁶, where a two-dimensional structured mesh is used to evaluate the impact of the amplitude and frequency of the Bidirectional synthetic jet on the aerofoil performance over a wide range of angles of attack. Three different jet oscillating frequencies are considered as well as three blowing ratios. The phase difference between the inflow and outflow jets, the position and the configuration of the jet exits are also evaluated. The results suggest that the amplitude of the jet is a key parameter to increase the lift coefficient and a gap between the inflow and outflow jet exits could positively influence the lift coefficient if the central location of the jets coincides with the separation point. On the other hand, the jet frequencies and the phase at which the jets operate do not seem to influence the aerofoil performance significantly. Finally, some guidelines and recommendations are provided to develop further the actual Bi-directional synthetic jet which may lead to its optimal design and manufacture.Item Open Access Characterising urban catchments for explaining storm runoff and application in UK flood estimation(2019-02) Miller, James; Brewer, Timothy R.; Hess, Tim M.The impacts of urbanisation on catchment hydrology have been the focus of investigation over the last few decades, but quantifying and predicting the impacts remains an ongoing area of active research. One such area has been improving characterisation of urban land cover to predict urbanisation impacts whereby lumped catchment characterisation of urban land cover limits the ability of attribution and modelling methods to consider the spatial role of land cover in runoff response. This thesis evaluates the potential for spatially explicit characterisations of urban land cover based on landscape metrics, commonly employed in landscape ecology, to explain storm runoff in urban catchments and their application in UK flood estimation methods. Rainfall and channel flow monitoring across two towns containing 18 variably urbanised sub-catchments were used to provide high-resolution time-series of rainfall and runoff and to identify storm events which were quantified using a range of hydrological metrics. Analysing storm runoff along a rural-urban gradient showed a lumped measure of urban extent can generally explain differences in the hydrological response between rural and urban catchments but not between more urbanised catchments in which soil moisture does not play a contributing role. Using high resolution geospatial data can improve the representation of the urban environment and landscape metrics can better represent the form and function of urban land cover, improving estimates of the index flood QMED over lumped catchment descriptors. Regression analysis of hydrological metrics showed the potential of landscape metrics for explaining inter-catchment differences in rainfall-runoff and point to the importance of considering the location and connectivity of urban surfaces. Landscape metrics provide a workable means of overcoming the limitations inherent in using lumped characterisation of complex urban land cover and their ability to express connectivity, size and location of urban land cover promises potential applications in hydrological applications such as UK design flood estimation methods.Item Open Access Characterization of gas-liquid flows in annuli.(2019-07) Eyo, Edem Nsefik; Lao, Liyun; Falcone, GioiaGas–liquid two–phase flow in annulus is encountered during certain operations in the nuclear, chemical and petroleum industries. In the Oil and Gas industry, the knowledge of gas liquid two-phase flow in annuli is important during underbalanced drilling of wells and hole clean operations. This technique offers several advantages over the conventional drilling method including reducing formation damage, preventing fluid losses and enhancing the safety and efficiency of operation. Proper design of underbalanced drilling operations hinges on the accurate prediction and monitoring of gas-liquid two-phase flow parameters such as flow regimes, liquid holdup and pressure drop; however the complexities associated with two-phase flows coupled with complex geometry makes this difficult. Limited studies exist in literature for gas-liquid flow hydraulics in horizontal annuli and no studies have been undertaken on the effects of annulus eccentricity on two-phase flow parameters including flow regimes, liquid holdup and pressure drop. In order to provide an improved fundamental understanding of gas-liquid two-phase flow in horizontal annulus and give insight necessary for accurate model development, detailed systematic experimental studies are conducted at atmospheric conditions in horizontal concentric and fully eccentric annulus formed using a 3 inch outer and 2 inch inner pipes. Flow parameters including flow regimes, liquid holdup and pressure drop are investigated using high speed camera, conductance probes and pressure transducers, with air and water as testing fluids. Results show that annulus eccentricity affects the flow regimes, liquid holdup and pressure drop. Predictive models are compared with experimental data and new models are proposed for flow regime identification and liquid holdup prediction, while a new real-time objective flow regime identification tool is developed using Support Vector Machine (SVM). The data generated from this study can be used for developing models which would be incorporated into commercial software for study of flow through annulus.Item Open Access Climate change impacts on urban wash services in Ghana.(2017) Boakye, Richard Opoku; Parker, Alison; Hutchings, Paul; Weatherhead, E. KeithThe global water and sanitation sector is faced with numerous problems. Evident from Sub-Sahara Africa is the lack of access to potable water and improved sanitation which has made water coverage and sanitation a worry for most governments in low and middle-income countries. Climate change will exacerbate these problems especially in the urban poor communities. There is therefore the need to investigate how to make urban WASH services climate proof. In line with achieving this aim, part of this work assessed the existing WASH vulnerabilities, assessed the potential impacts of developed hydrological scenarios on the existing vulnerabilities and developed recommendations for various stakeholders using the Rapid Climate Adaptation Assessment (RCAA) methodology. The other part of this work assessed the adaptive capacity of the urban WASH sector by applying the Adaptive capacity wheel (ACW) methodology. In the application of these two methodologies, qualitative empirical data were collected from semi-structured interviews, direct observations and focus group discussions. The empirical data collected helped to understand the stakeholders‟ climate change awareness, the linkages in the local vulnerabilities, and ways to enhance the adaptive capacity of the WASH sector. This research argues that the vulnerabilities of the WASH services are similar within and across the ecological zones in Ghana. These vulnerabilities resulted from intermittent water supply, poorly managed solid waste and lack of spatial planning which are problems in urban poor WASH management. Though these vulnerabilities were arrived by simple hydrological scenario, they show the need for adaptation measures to be incorporated into urban poor WASH planning. To integrate adaptation measures to achieve resilience, this work further argues that the adaptive capacity of the sector can be enhanced by improving the learning capacity and motivation of stakeholders as well as empowering larger-scale institutions to provide structures and guidance at the lower- and individual level.Item Open Access Coastal management and adaptation: an integrated data-driven approach(2019-03) Rumson, Alexander G.; Hallett, Stephen; Brewer, Timothy R.Coastal regions are some of the most exposed to environmental hazards, yet the coast is the preferred settlement site for a high percentage of the global population, and most major global cities are located on or near the coast. This research adopts a predominantly anthropocentric approach to the analysis of coastal risk and resilience. This centres on the pervasive hazards of coastal flooding and erosion. Coastal management decision-making practices are shown to be reliant on access to current and accurate information. However, constraints have been imposed on information flows between scientists, policy makers and practitioners, due to a lack of awareness and utilisation of available data sources. This research seeks to tackle this issue in evaluating how innovations in the use of data and analytics can be applied to further the application of science within decision-making processes related to coastal risk adaptation. In achieving this aim a range of research methodologies have been employed and the progression of topics covered mark a shift from themes of risk to resilience. The work focuses on a case study region of East Anglia, UK, benefiting from the input of a partner organisation, responsible for the region’s coasts: Coastal Partnership East. An initial review revealed how data can be utilised effectively within coastal decision-making practices, highlighting scope for application of advanced Big Data techniques to the analysis of coastal datasets. The process of risk evaluation has been examined in detail, and the range of possibilities afforded by open source coastal datasets were revealed. Subsequently, open source coastal terrain and bathymetric, point cloud datasets were identified for 14 sites within the case study area. These were then utilised within a practical application of a geomorphological change detection (GCD) method. This revealed how analysis of high spatial and temporal resolution point cloud data can accurately reveal and quantify physical coastal impacts. Additionally, the research reveals how data innovations can facilitate adaptation through insurance; more specifically how the use of empirical evidence in pricing of coastal flood insurance can result in both communication and distribution of risk. The various strands of knowledge generated throughout this study reveal how an extensive range of data types, sources, and advanced forms of analysis, can together allow coastal resilience assessments to be founded on empirical evidence. This research serves to demonstrate how the application of advanced data-driven analytical processes can reduce levels of uncertainty and subjectivity inherent within current coastal environmental management practices. Adoption of methods presented within this research could further the possibilities for sustainable and resilient management of the incredibly valuable environmental resource which is the coast.