Traditional measures used in the composting industry for ammonia and odor emissions control are those involving collection and treatment such as thermal oxidation, adsorption, wet scrubbing and biofiltration. However, these methods do not address the source of the odor generation problem. The primary objective of this thesis research was to develop preventive means to minimize ammonia and odor emissions, and maximize nitrogen conservation to increase the agronomic value of compost. Laboratory-scale experiments were performed to examine the effectiveness of various technologies to minimize these emissions during the active phase of composting. These techniques included precipitating ammonium into struvite in composting matrix before it release to outside environment; the use of chemical and biological additives in the form of yeast, zeolite and alum; and the manipulation of key operational parameters during the composting process. The fact that struvite crystals were formed in manure composting media, as verified by both XRD and SEM-EDS analyses, represents novel findings from this study. This technique was able to reduce ammonia emission by 40-84%, while nitrogen content in the finished compost was increased by 37-105%. The application of yeast and zeolite with dosages of 5-10% enhanced the thermal performance of composting and the degree of degradation, and ammonia emission was reduced by up to 50%. Alum was found to be the most effective additive for both ammonia and odor emission control; ammonia emission decreased by 45-90% depending on the dosage, and odor emission assessed via an dynamic dilution olfactometer was reduced by 44% with dosages above 2.5%. This study reaffirmed that aeration is the most influential factor to odor emission. An optimal airflow rate for odor control would be 0.6 L/min.kg dry matter with an intermittent aeration system. Quantitative relationships between odor emission and key operational parameters were determined, which would enable “best management practices” to be devised and implemented for composting. An empirical odor predictive model was developed to provide a simple and direct means for simulation of composting odor emissions. The effects of operating conditions were incorporated into the model with multiplicative algorithm and linearization approximation approach. The model was validated with experimental observations. / Applied Science, Faculty of / Chemical and Biological Engineering, Department of / Graduate

Mine tailings pose a health risk for populations and ecosystems in the Southwest; this is why effective, and low-cost solutions for the long term are needed. This work is groundbreaking since little information is available with regards to applying greenhouse studies of phytostabilization to the field for mine tailing remediation. Mine tailings from Iron King Mine and Humboldt Smelter Superfund (IKMHSS) site can be considered one of the worst scenarios due to the extreme conditions which prevent the growth of a vegetation cap. The high concentration of metals, such as arsenic and lead, highly acidic, lack of the nutrients carbon and nitrogen in the soil structure, and low microbial communities are factors that negatively affect plant growth. This project provides practical field-scale applications for the use of phytostabilization, which uses plants to create a vegetation cap that stabilizes metals in the root zone while preventing wind and water erosion in mine tailings. The project is divided into three main studies: (1) the assessment of the translation of successful greenhouse results to the field of phytostabilization using compost-assisted direct planting. This includes the use of different rates of compost as an amendment and different desert native plant species in addition to some potential parameters that could be used as indicators of a successful modification of biochemical and physical environment from a disturbed soil towards a more healthy soil when compost assisted direct planting phytostabilization is used; (2) the second study aims to evaluate the effect of the phytostabilization strategy on reducing windborne transport of particle and metal(loids) following the establishment of the vegetation cap. The results indicate that the vegetation resulted from direct planting decreases dust emissions from IKMHSS mine tailings; and (3) the third study focuses on one of the most important requirements for phytostabilization application in the field, the performance of the different plant species selected from the greenhouse studies. This performance was evaluated as the metal accumulation in aerial plant tissue based on metal concentration guidelines from the National Research Council as well as changes in the composition of plant species and canopy cover with time. The results derived from the translation of compost–assisted direct plating based on successful greenhouse results are showing the capacity of this technology on a field scale by maintaining a canopy cover over time that decreases mobilization by not hyper-accumulating metals in the aerial tissue and by preventing windborne particle dispersion with the potential of disrupting contamination pathways.

ABSTRACT Human transportation patterns have continued to shift and increase in rate as technology has made travel between spatially disparate locations more feasible. These movements are responsible for approximately one third of global carbon emissions, and account for one half of Vermont’s greenhouse gas output. Modeling transportation behaviors is difficult due to changing travel patterns and issues of surveying human participants. Long distance travel patterns are especially difficult and have not received the attention that urban mobility has within the literature. In this Masters thesis, I describe current methods of transportation data collection and propose new methods, as well as attempt to quantify the impact on Vermont’s roadways of the transportation-based tourism sector. In the first chapter of this thesis, I describe a GPS-based travel survey conducted over the course of one year, coupled with interview data of long distance trips undertaken by 10 participants. Long distance travel has historically been underrepresented in travel surveying due to its infrequency, resulting in decreased likelihood of capturing a long distance trip in a short travel study. By extracting points at intervals from the GPS dataset, it becomes possible to determine accuracy of trip matching between the two datasets with adjusted data collection methods. The second chapter examines transportation related to tourism in Vermont. As one of Vermont’s largest industry sectors, economic impact has been of particular interest to state planners. However, limited analyses of the transportation impacts of this sector are currently available. My research models route choice of drive through tourists, whom constitute 40% of visitors, attempting to begin quantifying tourist mileage and CO2 emissions within the state. Together, these studies expand knowledge on long distance transport data collection and the role of tourism in Vermont’s transportation mileage.

Abstract Non-linear methods have been utilised in modelling the processes on a flue-gas oxygen-content control system of a power plant. The ultimate objective is to reduce NOx and CO emissions by enhancing the control system. By investigating the flue-gas emission control strategy, the major factors affecting the flue-gas emissions have been determined. A simulator has been constructed, and it emulates a real process automation system and its physical processes. The process models of the simulator are: a flue-gas oxygen-content model, a secondary air flow model, a primary air flow model and a fuel feeding screw model (a fuel flow). The effort has been focused on two plant models: the flue-gas oxygen-content model and the secondary air flow model. Combustion is a non-linear, timevariant, multi-variable process with a variable delay. The secondary air model is a non-linear, timeinvariant (in principle), multi-variable system. Both phenomenological modelling (mass and energy calculations) and black-box modelling (neural networks) have been utilised in the Wiener/Hammerstein structures. It is possible to use a priori knowledge in model modifying, and therefore the model of flue-gas oxygen-content can be tuned on site. The simulator with precalculated parameters was tested in a full-scale power plant and a pilot-scale circulating fluidised bed boiler. The results in the power plant were remarkable since NOx emissions decreased significantly without increasing CO emissions.

Land-cover change is the second most important source of anthropogenic greenhouse gases (GHG) emissions, generating around 7-14% of the total carbon dioxide (CO2) emissions around the world. More than one million km2 of tropical forests were lost during the period 2000-2012 around the world, from which forests-to-pasture conversion was the most common land-use change in key regions such as the Amazon. Strategies to mitigate climate change by reducing deforestation and forest degradation (e.g. REDD+) require country- or region-specific information on carbon (C) stocks in forests and their dynamics with land-cover change, in order to develop accurate Forest Reference Emission Levels (FRELs) to be submitted to the UNFCCC as benchmarks for assessing the performance of countries participating in REDD+ activities. Nevertheless, FREL development is incipient and their elaboration is mostly based on highly uncertain Tier 1 information from IPCC. In this research I present the first region-specific Tier 3 information and emission factors on soil, dead wood and below-ground biomass C pools and their dynamics during 20 years of forest-to-pasture conversion under different management practices in the Colombian Amazon. Based on these region-specific Tier 3 emission factors on C stocks in forests and their change after pasture establishment, I report for the first time the net CO2 emissions from forest-to-pasture conversion in the Colombian Amazon. The results also demonstrate that Tier 3 region-specific information is 70% higher and is substantially more accurate than estimates based on using IPCC Tier 1 information, which emphasizes the urgency for countries implementing REDD+ to develop improved data and methodologies. The information reported here will contribute to strengthening the REDD+ National Strategy of Colombia, by supplying accurate data and models that can be included within the next Colombian FREL.

The quality of electricity infrastructure and supply to a nation is seen as vital for the development of the local and regional economy. In recent times, electricity generation industries worldwide have undergone significant changes pertaining to the kind of technologies used. These changes were made in order to address concerns related to energy security and sustainability. South Africa has been identified as a carbon-intensive economy, with the electricity sector being at the high end of the carbon intensity spectrum. The need to analyse the socio-environmental impacts of existing electricity generation techniques becomes vital when taking into account the transitions in the South Africa electricity industry. Socio-environmental impacts are categorised into public, environmental and occupational impacts, based on the point of impact. The methodology used to quantify these impacts is based on the Impact Pathway Approach used in the Externalities of Energy study. The Externalities of Energy study was devised in Europe and has gained prominence particularly in developing countries because of its ability to adapt to local conditions. Since South Africa is a developing country, the methodology is suitable for the quantification of externalities when analysing scenarios that have a dearth of local data. iii South Africa historically focused on non-renewable electricity generation mechanisms. This was done primarily because of the abundant supplies of coal and secondly because of the need to provide electricity at affordable prices to the masses. The focus of the analysis is set on impacts caused by coal and nuclear electricity in South Africa, since these two technologies together contribute to more the 95% of the electricity generated. The impacts in each category are identified, prioritised, analysed and quantified. Once impacts are quantified, monetary costs are attributed to the impacts. The aggregation of the costs caused by the impacts results in determining the damages associated with the quantified impacts. Monetary damages individually are not of much use, and therefore the significance of such damages are underlined once calculated. Determined monetary damages are interpreted in average and total terms relative to the total electricity generated with the intention of highlighting the significance of the costs. The average damage costs are compared to existing electricity prices, which enables policy- and decision-makers to segregate the damages relative to electricity prices. The results of this analysis should enable policy-makers to prudently make decisions about the significance of the social and environmental impacts associated with the dominant non-renewable electricity generation technologies in the country while prioritising the sustainability of the society and environment. / Thesis (PhD)--University of Pretoria, 2013. / cp2013 / Graduate School of Technology Management / PhD / Unrestricted

Master of Science / Department of Mechanical and Nuclear Engineering / Kirby S. Chapman / The United States Environmental Protection Agency (EPA) continues to tighten pollutant emission regulations throughout the United States. As a result, the need to reduce air pollutants such as nitrogen oxides (NO[subscript]x) and carbon monoxide (CO) remains a challenge for pipeline operators. NO[subscript]x formation is primarily a function of in-cylinder combustion temperatures. A challenge for engine researchers is to identify methods to lower combustion temperatures while maintaining complete combustion. Blending hydrogen into an engine's fuel can lower in-cylinder combustion temperatures and reduce pollutant emissions. Hydrogen has a wider flammability range in comparison to natural gas, which allows for leaner engine operation and lower combustion temperatures. Specifically, the very high molecular diffusivity of hydrogen creates a more uniform mixture of fuel and air. Hydrogen also has very low ignition energy, which translates into easier combustion. This paper presents test results of using hydrogen as a fuel additive for a large bore, two stroke cycle, single cylinder, natural gas fueled Ajax engine in a test laboratory. The engine was first operated at the test point on pure natural gas and allowed to stabilize. Then a mixture of hydrogen and natural gas at various molar percentages was introduced. The engine was operated entirely on the blended fuel without a pre-combustion chamber first. Next, a pre-combustion chamber was installed and the blended fuel was supplied to it while the main combustion chamber operated on pure natural gas. Engine and emissions data were recorded and physical observations were also noted, such as engine misfires. Results showed that the addition of hydrogen into the fuel gas without the use of a pre-combustion chamber reduced emissions. The addition of the pre-combustion chamber reduced NO[subscript]x emissions without the use of hydrogen. For both configurations, the engine ran smoother with no noticeable increase in misfires or detonation. The pollutant emission reduction and engine combustion stability suggest that hydrogen as a fuel additive would be a good method to meet emissions requirements.

[pt] O impacto ambiental causado pela queima de combustíveis por veículos automotivos, atualmente, atua como restrição na especificação de parâmetros de projetos de motores em vários Países. O uso de etanol hidratado no Brasil criou a necessidade de determinar o comportamento das emissões de poluentes sob condições típicas de projeto, auxiliando o estabelecimento de uma política de controle de poluição. Nesta pesquisa, as emissões de um motor monocilíndrico foram medidas, basicamente óxido nítrico, monóxido de carbono e aldeídos. Usou-se gasolina comercial e etanol hidratado como combustíveis. A influencia da taxa de compressão, da relação combustível-ar e da quantidade de água no etanol, na performance do motor e no comportamento das emissões de acetaldeído foi desenvolvido para cálculos em computador digital, concordando bem com os resultados experimentais. Usando este modelo, valores de emissões de poluentes por motores de combustão interna, usando etanol hidratado foram calculados, mostrando uma tendência bem definida que pode ser útil para políticas de controle de poluição. / [en] The impact on the environment caused by the burning of fuels from automotive vehicles, nowadays, acts as a restriction on the specification of the engine designe parameters in several countries. The use of ethyl acohol-ewater blends in Brazil has created the necessity of determining the pollutant emission pattern under typical design operating conditions aiming the stablishment of a pollution control policy. In this research, emissions from a monocylinder engine were measured, bassicaly ntric oxide, carbon monoxide and aldehydes. The engine was fueled with commercial gasoline and ethyl alcohol-water blends. The influence of the compression ratio, air-fuel ratio and water content of blens, on the perfomance of the engine and pollutant pattern was studied. A Kinetic model, taking into account CO and NO formations mechanisms, as well as acetaldehyde emissions was developed for digital computer calculations, matching the experimental results to the calculated ones. The, using this model, values of the pollutant emissions from internal combustion engines, fueled with ethyl alcohol-water blends were calculated showing a very well defined trend, which can be useful for pollution control policies.

Climate change stabilization requires an unprecedented effort to change our current approach to energy production and consumption. While rising energy prices are drawing increased attention to reducing energy demand, heightened concern about the environmental consequences of fuel choice requires that this demand be met at lower emission levels. In Canada, the realization of commitments to our GHG emission goals entails reducing residential energy use - a sector responsible for close to 20 percent of end-use energy consumption. This study focuses on the energy demand and emission levels of space and water heating, since these two components comprise 76 percent of residential energy demand. Ground source heat pumps (GSHPs) are a technology that provides heating at 25 to 30 percent of the energy consumed by even the most efficient conventional alternatives. GSHPs have been identified as the most energy-efficient, environmentally clean, and cost-effective space conditioning systems available. However, their drawbacks have been high capital costs, and uncertainty about whether the electric power used by heat pumps has higher system-wide emissions. This thesis delineates how adoption of GSHPs in the residential sector can help align Canada’s technology choices with commitments made to the Kyoto Protocol. The manuscripts delineate conditions under which GSHP systems achieve the largest net emission reductions relative natural gas, heating oil, and electric heat counterparts. Electricity generation methods and emissions embodied in inter-provincial and international electricity trade are shown to significantly affect the emission savings achievable through GSHP. The thesis quantifies how relative fuel prices influence annual operating savings that determine how rapidly the technology can achieve payback. This analysis reveals GSHPs to hold significant potential for substantial GHG reductions at a cost savings relative to conventional alternatives; the time horizons for payback are as short as nine years for average-sized homes, and significantly shorter for larger homes. / Science, Faculty of / Resources, Environment and Sustainability (IRES), Institute for / Graduate

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