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Student Number : 0418764K - MSc (Eng) dissertation - School of Civil and Environmental Engineering - Faculty of Engineering and the Built Environment / Increasing quantities of finer wastes often contain reactive sulphide minerals and high water contents that pose stability and environmental concerns. This study investigates how electrokinetic process can be improved, to make it more viable towards dewatering finer coal slurries. In the electrokinetic process, a direct current induces the movement of water out of a porous material. A wooden test box was filled up to two-thirds with fine coal slurries. Electrokinetic Geotextiles (EKGs) and brass were used as electrodes. The conducting wires were attached to each electrode and connected to a DC source to form an electro-osmosis cell. Current was passed through the cell and water moved to the cathode where it was withdrawn. The dewatering efficiencies ranged from 13.13 to 109.84 ml/Ah. The energy consumptions ranged from 5.23 to 14.03 kWh/m3 and are in line with those recorded by Johns (2005). Conductivity and pH measurements were taken. EKGs performed better than brass electrodes.

The primary goal of this study was to evaluate a new device and system, designed to optimize the performance of standard low pressure air diffusers in two types of aerated systems (activated sludge and aerobic sludge digestion) and to decrease overall energy consumption. Aerated treatment systems are very important in the treatment of wastewaters and management of sludges. The activated sludge process is widely used to treat wastewater from both industrial and municipal sources. However, they are costly to operate because oxygen is marginally soluble in water and standard low pressure (8 psig) diffusers provide marginal mixing and minimum retention. The newly patented device is referred to as TotalMix and is a type of pneumatic mixing system. TotalMix introduces air under high pressure at regular fixed intervals. During the tests the frequency of air delivered, the pressure, and the period of pressured air delivery was varied manually or through feedback control to optimize oxygen transfer and the interaction with a regular aeration system. Various chemical parameters, most importantly dissolved oxygen, were measured and compared to the new approach, using the TotalMix in combination with standard diffuser systems. The new System was tested in different sized tanks (17,000 L and 380,000 L), different concentrations of total solids (TS), using different airflow rates and different diffusers (membrane fine bubble diffusers, ceramic fine bubble diffuser, and course bubble diffuser). The statistical evaluation of the experiments indicates an increase in oxygen transfer rate with a concomitant decrease in energy consumption at low airflow rates. / Master of Science

Texas is the leading producer of renewable energy in the U.S, and Dallas-Fort Worth (DFW) is the largest metropolitan area in the state. Texas has a deregulated energy market, with three types of providers: privatized, public-owned, and co-operatives. Privatized providers compete in the deregulated market, and consumers choose between hundreds of electricity retailers. Public-owned providers are owned by the municipality, and electricity consumers that live within the city limits must use the municipal provider. Electric co-operatives operate similarly where customers within the region must use the co-operative, but instead of being owned by the city, co-ops are owned by the members (customers). To date, the availability, cost, accessibility, and outreach of renewable electricity among these provider types remains unclear. For this reason, my research examines the renewable energy market in DFW by asking: (1) Who has access to renewable energy and how do they understand it? (2) How do electricity retailers distribute and make renewable energy available? and (3) If consumers can choose their provider, why do they select certain electricity plans over others? My findings suggest that while many consumers want or are open to using renewable energy, uncertainties surrounding how to find or choose a provider, price, and lack of information about renewables are obstacles for consumers to access renewable energy. Additionally, while renewable energy is widely distributed in the region, there are disparities in renewable energy options.

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An investigation into economical energy usage in freeze tunnels was conducted. Freeze tunnels are commonly used in the food processing industry to freeze products, and in some cases may use large amounts of electricity. An actual freeze tunnel was observed and modeled on a computer. A parameter study was conducted. The results of the parameter study indicated the efficiency and energy costs in freeze tunnels may vary widely. Important parameters included the Nusselt number, air temperature, and the ratio of fan work divided by the useful refrigeration effect. Although no single set of optimum conditions were found, methods for improving the effectiveness of freeze tunnels, both in existing and future designs, were discussed. It was also concluded that the ratio of fan work to the freeze tunnel's useful refrigeration effect was a dominant factor in the energy cost of operating a freeze tunnel.

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A study was performed to gain an understanding of the feasibility of an Earth Coolant Tube for use in cooling and heating air for residences and industry. It was concluded that previous studies did not include the effect of coolant tube depth or coolant tube operation over long periods of time. A numerical methods approach using finite difference form of the general energy conduction equation was used to evaluate these effects. It was concluded that a coolant tube 1 foot in diameter and 100 feet long could provide as much as 1/6 ton of refrigeration for a 4 month time period. It was also concluded that for coolant tube performance. This study also presents estimates on expected rates of energy transfer for coolant tubes, and recommends a simplified approach for designing coolant tubes.

Energy consumption and correlated greenhouse gas emissions are a big global problem. It affects all parts of society, and each industrial sector must work toward reducing itscarbon footprint. This thesis details the research of different methods to model the energyconsumption of video streaming, and works towards creating a final model. The videostreaming process is broken down into a core process consisting of head-end, distribution,transmission, and terminals. The process that contributes the most to energy consumptionat the head-end is found to be video encoding. This thesis explores the energy consumption of video encoding in depth and how it is affected by parameters such as hardware,codec choice, codec preset selection, and video details such as resolution, framerate, andduration, but these parameters are found to be insufficient to accurately model the energyconsumption of video encoding. In distribution and transmission, the highest contributor is found to be content delivery networks. The energy consumption of content deliverynetworks is investigated however no appropriate model is found. For terminals, the mostimportant factor is the kind of terminal used. The energy consumption of televisions, desktop computers, laptops, and mobile terminals is investigated, and models are presented foreach. The thesis also discusses the different models, their advantages, and their shortcomings. Additionally, an application to visualize features of the model is presented.