Accelerated carbonation involves exposing a material to a concentrated atmosphere of carbon dioxide, and can be used to treat hazardous wastes and soils and create new construction materials. The present work examines the use of accelerated carbonation to reduce the hazardous properties of wastes as a means of reducing the costs of disposal to landfill, and then develops the process to manufacture aggregate from the waste removing it from landfill disposal completely . A range of thermal wastes, including those from cement, metallurgical and paper processes, were found to be reactive with carbon dioxide. Many of these wastes are hazardous on account of their alkaline pH, which carbonation partially neutralizes, effectively allowing reclassification of the materials as stable non-reactive hazardous wastes under the Landfill Regulations. Cement and paper wastes were highly reactive with carbon dioxide, and were considered for use as cement substitutes to reconstitute non-reactive wastes into aggregate. Previous work had suggested that carbonation and pelletising were not compatible due to differing optimum conditions. This issue was investigated by considering the effects of the mix formulations and machinery parameters. The pelletising and carbonation processes require widely different moisture contents. The disparity is due to the need for total saturation of the material to form bonds between grains during pelletising, and an open pore network for carbon dioxide to penetrate. To achieve the two simultaneously, several methods were investigated. Chemical catalysts including sodium hypochlorite and sodium sulfite increased carbonation in a saturated material. However, curing the formed aggregates in carbon dioxide was found to be the most economic solution. A pilot scale process was developed based upon the laboratory results. A bespoke rotary carbonation reactor was developed to produce aggregate in bulk for commercial testing. Aggregate which was subjected to accelerated carbonation, has enhanced strength and durability compared to aggregate exposed to natural carbonation. The aggregate was successfully used to produce lightweight concrete with comparable strength to concrete made from commercial lightweight aggregate. Aggregate was also supplied for a research project to investigate the use of recycled materials as a horticultural growing medium.

The modelling of infiltration and moisture movement within a porous medium requires information on the moisture retention and hydraulic conductivity properties. In this study, the unsaturated hydraulic behaviour of a compacted waste sample based on the composition of Lyndhurst Landfill site in Melbourne, Australia was investigated in laboratory. Two fundamental aim of the study were to establish the moisture retention characteristics of Municipal Solid Waste (MSW) sample and measure its unsaturated hydraulic conductivity. In landfilled waste, the particle and pore size distribution, heterogeneity of waste composition and leachate chemistry complicate the determination of moisture retention and hydraulic conductivity. In this study the modification and use of a standard pressure plate apparatus was described which can be used establish moisture retention properties of samples of 230 mm in diameter. The experiments showed that the moisture retention characteristics of compacted waste sample were comparable to soils. It has been shown that water retention in waste is a function of its position relative to the phreatic surface, in other words, its hydraulic boundary conditions which will vary with elevation. Some difficulties and limitations of using this method were discussed. As with conventional inert soils, laboratory determination of unsaturated hydraulic conductivity is difficult and recourse is often made to analytical methods as those presented by van Genuchten (1980). One aim of this study was to compare the unsaturated hydraulic conductivity of MSW obtained using Passioura' s (1976) onestep outflow test method with predictions using van Genuchten's model. Good agreement is observed between the predictive model and experimental method for unsaturated hydraulic conductivities at low moisture contents but there is poor agreement at high degrees of saturation. This latter discrepancy is attributed to the difficulty of measuring retention properties of large pores at low suctions and the applicability of the van Genuchten model to such a material. Results also suggest that dual porosity exists within waste.

The ICSSWH (Integrated Collector Storage Solar Water Heater), apart from being the oldest is also the most economical means of solar water heating. The effect of modifications in the collector geometry has frequently appeared in the literature, and over the time, has resulted in different designs. These designs differ mainly on the site of installation as well as the target application. A novel design created by Professor T Muneer at Napier University, utilizes fins inside the storage tank to improve the heat transfer. The reported field tests of the fin type ICSSWH have indicated a 10 % improvement in the solar fraction compared to unfinned. As ICSSWH is the lowest cost, it presented a possible solution for the Scottish market where Energy Saving Trust estimates that 50% of hot water demand of a household can be met through solar water heating. In the present research program, two prototype collectors (one with- and one without fins) were fabricated at Napier University by the author. The collectors were then tested in the laboratory on identical experimental schemes to determine their respective performance. Simulations based on analytical modelling were then undertaken, using numerous experimental data for validation that were obtained during the course of the present work. A high degree of conformance was noted between the two. Furthermore, for a deeper insight, Computational Fluid Dynamics (CFD) analysis was performed. This research focuses on the qualitative and quantitative assessment of the heat transfer due to the fins. The difference in the performance with respect to the change in tilt angle was also studied. This study can therefore be utilised for developing solar water heating systems for any given location. Note that there is an intrinsic link between the latitude and inclination angle of the collector plate. The nocturnal loss from the collector is the principal factor that has inhibited the wide spread use of the ICSSWH. The remedies to abate this problem have therefore been attempted. In addition to that, the collectors have to be integrated with the domestic hot water supply system and plumbing considerations have to be incorporated within the overall design. The supply circuits were worked out and the measures for freeze and boil protection were devised. The optimization of any system is an intrinsic task particularly when several variables are involved. On the basis of the obtained results from simulations and experiments, the influential design variables were identified. The values for these variables which lead to the optimal design in terms of thermal performance were assessed while keeping the overall manufacturing cost of the collector as low as possible. Recommendations for future work have also been presented.

This thesis deals with the following aspects of renewable energy technology; solar energy modelling within the urban environment, performance of building integrated renewables including solar photovoltaics and micro wind technology. The development of hydrogen technology and electric zero emission transport is also reviewed. Incident solar irradiation models have been developed to accurately incorporate the effects of shading, in order to enable the detailed simulation and estimation of solar energy systems within the urban environment. Both the Integrated Slope Radiation Model (ISRM) and the Sky Radiance Distribution Model (SRDM) have been developed to use readily available horizontal sub-hourly or hourly solar global and diffuse irradiation data. Shading parameters caused by the surroundings, such as building and trees, can be incorporated into the models. A software package based on these models has been developed to allow the design and simulation of solar energy systems. Horizontal solar global irradiation data is readily available around the world. However, diffuse irradiation data is available to a lesser extent. To resolve this problem and enable the above mentioned incident solar irradiation models to be used throughout the world a simple regression set was developed between the diffuse ratio, k, and clearness index, kt, to enable the estimation of horizontal diffuse irradiation from its horizontal global counterpart. A review of building integrated renewable technology has been carried out. This includes the review of the performance of Edinburgh Napier University photovoltaic facade which has been in operation for over three years. Building mounted micro turbine technology is also reviewed. Performance analysis of three micro wind turbines installed on the rooftop of Edinburgh Napier University was undertaken, along with an analysis of the available wind regime observed at roof level. A software package was developed to aid the monitoring and analysis of both micro wind turbines and their observed wind regime. Hydrogen technology is reviewed as part of the development of Napier Hydrogen Research Facility, enabling the demonstration of hydrogen generation, storage and use from renewables. Finally, an analysis and comparison of a zero emission electric scooter with a conventional petrol car for use as urban transport was carried out. A driving cycle analysis was also undertaken to determine the environmental impact of both vehicles.

This research is mainly focussed on solar radiation in the UK. It can be divided into four main areas; evaluation of models, analysis of the relations between temperature and solar radiation, critical analysis of the projected future data for the UK and the improvement to the UKCP09 Weather Generator (WG). From the evaluations of models carried out, the Liu-Jordan model performs well for estimating the average hourly global and diffuse radiation. At the individual hourly level however, a number of problems were observed. Regarding clear- sky radiation models, for semi-arid climatic conditions Page model was found to be suitable and for humid climates Yang model is recommended. As for all-sky radiation models, the MRM and Yang model were selected. For the UK, the MRM was found to perform better than the Yang model. Furthermore, a study was carried out to analyse the relationship between temperature and solar radiation. The development of temperature-based mathematical models to obtain mean-daily irradiation was established. A procedure to decompose daily to hourly temperatures was evaluated with respect to world-wide locations and its performance found to be satisfactory. As part of the UKCP09/COPSE project, detailed analysis on the future projected data was carried out to critically evaluate sol-air temperature and the likely change that may occur in the key climatic variables, i.e. temperature, sunshine duration and solar irradiation. Drastic increase of sol-air temperatures and shifting trend of daylight illuminance were found. Furthermore, a sensitivity test was also carried out to analyse the effects of each input variables on sol-air temperature. As a result of the present investigations and communications with the UKCP personnel a new version of WG was released with appropriate modifications. A comparison of the now old- and new WG data sets has been made. Improvements in ratio of diffuse to global radiation and sunshine datasets were found.

No description available.

Wastewater activated sludge treatment plants are among the most common forms of biotechnological application. These plants breakdown influents of organic and non-organic matter using a complex bacterial consortia in an aerobic aqueous suspension. One of the most persistent and widespread problems associated with these plants is the formation of thick viscous chocolate coloured scums or foams on the surface of the aeration tanks of the plants. These foams can reach depths of 1.0-1.5 metres and can transfer to the secondary clarifiers and into open water sources. They not only reduce operational efficiency of the plants but they have also been associated with the transfer of pathogens such as Mycobacteria, nocardioform actinomycetes and the opportunistic pathogen Nocardia jarcinica. This investigation had two main aims: 1. To analyse two WWTP with very different characteristics to identify the causative organisms and factors of foaming in them both. 2. To design a sampling strategy for further investigations into foaming In this study the molecular techniques to permeabilise the actinomycetes (the probable foam causing organisms) and hybridise them with specific oligonucleotide probes for use in Fluorescent in situ hybridisations (FISH) were evaluated. In addition four novel 16S rRNA oligonucleotides were designed to detect Nocardia species in environmental samples. FISH using a nested set of probes covering Rhodococcus spp, Gordonia spp, Nocardia spp and the mycolata was evaluated for use in the detection and enumeration of target orgamsms in situ allowing the spatial make up of environmental filamentous flocs to be examined. The operational data from a large pharmaceutical waste water treatment plant was obtained which provided a comprehensive study of the day-to-day workings of the aeration basin over a three-month period, during which a foaming incidence occurred. This data was analysed statistically to find possible indicators of the causes of foaming. Several conclusions were made about the causes of foaming in this plant. An alternative PCR-ELISA methodology was devised to produce semIquantitative enumeration of actinomycetes within environmental samples. A sampling regime was devised for the further study of foaming in activated sludge systems. This regime incorporates the use of FISH; PCR-ELISA to identify and characterise the bacterial consortia within the mixed liquor suspended solids of activated sludge plants, and analysis of the physical characteristics of the plants. A combination of these techniques will eventually allow not only control of foaming but also prevention.

No description available.

If the UK is to address its energy reduction targets, it is vital to understand energy use behaviours and to devise technology that positively encourages domestic occupants to use less energy. This study is cross-over research that spans energy research, social science and socio-technology. The work presented in this dissertation reveals the domestic energy saving potential of the use of In-hone Displays (IHDs) by quantifying changes in actual energy consumption and then evaluating these changes using social science research techniques to document the psychological nature of the human interaction with a digital user interface (UI). Many studies have investigated how IHDs for domestic electricity use change behaviour; the findings of this unique 37 month pre-normative study, the first of its kind in the UK, show that the coloured dual-fuel IHD had a positive effect on consumption behaviour and energy reduction. However, the exact difference in energy consumption between experimental groups is dependent on the type of normalisation condition applied to the recorded energy consumption. After the first six months of monitoring, those with a coloured IHD reduced their gas consumption by an average of 20% compared to a control group; this was tested to be statistically significant (p < .05). This difference in consumption was similar for those living in flats and those living in houses. The quantitative figures are reinforced by the findings from questionnaire and the semi-structured interviews, which show that those with an IHD were significantly more likely to reduce their gas consumption and reported increased use of the controls and settings like thermostats for heat-related appliances. Thirty-one months later, this change in gas use behaviour persisted. Over the total 37 month monitoring period, the majority of participants continued to engage with the IHD on a daily basis and consumed 27% less gas than the control group. This difference reached statistical significance (p=.05). The questionnaires conducted 31 months after the initial findings found that those in the intervention group had statistically higher gas reducing behaviour change scores (p < .05). The first six months of energy data show that the sample group with the IHD used 7% less electricity than the control group. The difference in group means was found to not be statistically significant (p > .05). The difference in electricity consumption was considerably higher in the sample living in houses than in the sample living in flats. Qualitative feedback from the participants suggests that the use of the IHD had a slight positive effect on users' consciousness of reducing electricity consumption. However, a larger portion of the occupants with no IHD were similarly confident in ingrained methods of regulating and reducing their electricity consumption. Thirty-one months later, the difference in electricity consumption was substantially higher than was measured for the first six months. Over the total 37 month monitoring period, the intervention group consumed 21% less electricity than the control group. This was not statistically significant (p > .05), the interviews found that those with an IHD did not directly attribute their reduced use of electricity to the IHD. Rather, they maintained low levels of electricity use because it was an ingrained habit long before they used the IHD and for fire and safety reasons. Between the 6 month report and 31 month report, both experimental groups reduced the amount of electricity and gas they consumed. This was attributed to changes in weather patterns and occupants growing more accustomed to their new home. The properties with highest gas consumption reduced their consumption closer to that predicted by the Standard Assessment Procedure (SAP). The research found contrasting differences in how the two utilities where perceived and used. This was evident when the energy data was divided into groups based on occupancy. Larger savings in gas consumption was seen in the intervention group with lower occupancy: the intervention group consumed considerable more electricity than the control group in the lower occupancy dwellings, and consumed considerably less in the larger occupancy dwellings. Electricity was described as a luxury, used to maintain a certain quality of life. Those with younger dependents felt it necessary to provide them with as much electronic luxury as they could. Electricity was relatively freely accessed and used by all residents with little resistance if a justified reason was given for its use. However, space heating was perceived as a sacrificial commodity. Heat was described as being relatively easy to regulate with the use of blankets and extra clothing. Heating controls were perceived to be out of reach for many but one or two in the household. This tended to be in control of the person responsible for the majority of household tasks. The users of Ewgeco IHD commented more on the device's ability to promote new gas saving behaviour in order to reduce gas consumption. In contrast, the visual representation of real-time electricity consumption was used more as a safety feature, and appears to fail to produce significant electricity reduction. The participants used the electricity consumption information to reinforce their existing levels of electricity use awareness and it highlighted electrical appliances that had been left on to them. This was reported to be specifically useful at times when the occupants were retiring from the living spaces in the home. These findings demonstrate that a simple ‘push-information' style IHD may need to evolve further with greater smart home control functionality, internet capability and user interaction for this technology to be part of the low-carbon solution. However, it has also been demonstrated that, for particular household groups, IHDs can lead to longer term changes in energy consumption behaviour, specifically for heat.

In the wood fuel supply chain, the water contained in the product determines one aspect of the quality of the wood. It is necessary to reduce the moisture content (MC) of the wood in order to reduce transport and storing costs and also to increase the heating value of the wood. In this thesis a solar thermal application has been developed to dry woodchips using exclusively solar energy. The novel solar woodchip dryer comprises a small woodchip dryer and a solar air thermal system (SATS) to increase the temperature of the drying air. The particularity of this woodchip dryer is that the input air flow is governed by a photovoltaic driven fan. Based on the experimental results obtained, the woodchip dryer and the SATS thermal performance were modelled and a simulation tool for predicting the dried woodchip production during a period of time has been developed. Two small capacity dryers, a thin and a thick layer dryer, have been designed and built to dry woodchip based on the flow capacity of the SATS. The drying performances are studied for both configurations comparing the drying times, drying rates and efficiencies at different test conditions. The drying curves obtained from each test are modelled as a function of key parameters, temperature and velocity employing the Page model equation. Based on the experimental results, a drying model has been successfully developed to predict the MC when the woodchip dryer operates within a range of drying conditions. A quantitative and qualitative analysis of the SATS thermal performance has been conducted employing various solar air collector configurations under Scottish weather conditions. The pneumatic characteristics of the solar dryer including the dryer are determining for the analysis of the system performance. Because of the PV driven fan electrical characteristics, the SATS presents a unique operation regime in which air flow depends exclusively on solar radiation. Thus the SATS thermal performance has been successfully modelled as a function of irradiance. The study necessarily includes the effect of environmental factors such as wind and cloudiness in the transient regime. The potential of using a solar woodchip dryer has been assessed based on the results obtained from modelling the dryer and the SATS together. The feasibility and employability of using the solar dryer for drying woodchips is discussed considering the productivity, the energy savings, costs and integration.