<p> The photocatalytic reaction has been integrated as a developing technology for various applications such as air and water remediation, and self-cleaning surfaces. The photocatalysis is an emerging pathway of heterogeneous photocatalysis and physical chemistry. In heterogeneous photocatalysis, semiconductor compounds, mainly TiO₂, ZnO, CdS, and WO₃, have been utilized especially for water treatment and contaminant degradation. Various pollutants, such as aromatic compounds, dyes and surface active agents, can be degraded with photocatalytic techniques. Ultraviolet light and visible light are the most important sources of radiation to conduct photocatalytic reactions. </p><p> In this study, we have developed a combined method using microfluidics and photocatalysis for wastewater treatment. This technique represents a promising solution for contaminant degradation that has advantages such as continuous operation, large surface area to volume ratio, rapid response, and fine flow control. The experiment was conducted by exposing samples to UV light with methylene blue as the model pollutant and titanium dioxide (TiO₂) as the catalyst. The degradation of methylene blue was monitored with spectrophotometry. The effects of variables, such as residence time, chip thickness and intensity have been investigated. The photocatalytic degradation has been determined to be a pseudo-first-order reaction with a rate constant (0.18 <i>C</i><i>_C</i>^0.334) related to catalyst concentration. Once optimized, this system could be scaled out to process wastewater at a larger scale.</p>

<p> The main aim of the study was to introduce new filtering techniques to better the prediction of subsurface water contaminant transport. Hybrid nudging-ensemble Kalman filter (HNEnKF) and ensemble adjustment Kalman filter were proposed in this study. EnKF with traditional nudging were gradually applied promptly in the case of the HNEnKF. Other techniques whose performance were evaluated along with HNEnKF are a numerical method, ensemble Kalman filter, and ensemble adjustment Kalman filter. In this study, the HNEnKF and the EAKF are expected to improve in robustness and convergence due to the nudging properties and the assimilation of observations with a nonlinear relation to model state variables respectively. To appraise the HNEnKF and EAKF techniques, the numerical (finite difference) method and EnKF assimilation method were used. These simulations were executed with a three-dimension subsurface contaminant transport model with a first-order decay rate parameter.</p><p> A summary of this research are outlined below: </p><p> &bull; To investigate the performance of HNEnKF and EAKF data assimilation technique in subsurface water contaminant transport modeling compared to the numerical solution and ensemble Kalman filter technique.</p><p> &bull; To apply HNEnKF and EAKF data assimilation scheme in subsurface water contaminant transport.</p>

<p> The objective of this research is to develop a simple and innovative technology that effectively lowers chemical concentrations to meet Environment Protection Agency (EPA) drinking water regulations. This study focuses on fabric inclined settling screen development for application to small community drinking water treatment systems to help them with compliance, particularly with disinfection by-products (DBPs) through enhanced solids contact. The technology developed combines fabric filters with the traditional inclined plate concept. Fabric material performance and serviceability was first checked by exposure to a drinking water treatment environment and then measuring turbidity, total dissolved organic carbon, and UV254. The study suggests a product like Pureflo (a polyester) is the more appropriate material in acidic and neutral conditions and one like Surefil (rayon/polyester blend) is the more appropriate material in basic conditions. The Pureflo product was used in bench scale systems to determine performance of the designed fabric inclined settling screen. Experiments with different coagulants, different angle, and different layers of fabric screens was conducted. A pilot scale system was set up in Vandalia, MO to test the feasibility of the fabric screen of turbidity, TOC, UV254, and TTHM removal. Results indicated that screens made from pureflo with angles from 30&deg; through 70&deg; under acidic condition have positive effects on sedimentation enhancement.</p>

<p> Minimizing coastal wetland loss is a high priority in coastal areas throughout the world. Commonly used protection methods are costly, and may have negative impacts on the surrounding areas. The Wave Suppression and Sediment Collection (WSSC) system is an alternative shoreline protection structure. Primary goals of this study are to evaluate the sediment collection performance of three WSSC units under different sand conditions, to determine the performance characteristics of the units in terms of energy coefficients, and to validate a Computational Fluid Dynamic (CFD) model to determine the parameters governing wave attenuation. Sand collection results showed the units collected a minimum of 25% more fine sand than coarse, and that collection was affected by pipe size and row location. A mass transfer model was developed to predict the collection rate of sands based on wave and sand characteristics. The model fit experimental data well, with R2 values over 0.84 for three units and two different sands. A mass transfer coefficient alpha (a) was used within the model to compare the actual sand collection to the predicted amount. Resulting alpha values showed that sediment collection efficiency is governed by open area and pipe location within the devices. Performance characterization showed the WSSC units have wave reflections of 0.45 to 0.80, wave transmissions ranging from 0.10 to 0.40, and wave energy dissipation between 0.50 and 0.90, depending upon the unit and wave conditions. The WSSC units reflect more wave energy and transmit less energy compared to other breakwaters. The CFD model was validated using experimental velocity measurements. Statistical tests showed model velocities were not significantly different from experimental data. Units were modeled parametrically using CFD. Results indicated that wave reduction could be increased by decreasing pipe diameter, reducing the face slope, or increasing the number of rows.</p>

<p> Ordered Mesoporous Carbons (OMCs) with well-controlled pore structure and narrow pore size distribution demonstrated great potential as highly functional adsorbents. The pore size and surface chemistry of OMCs were considered two of the most important factors that affect the adsorption capacity of organic compounds. The objective of this study is to optimize the structure of OMCs for resorcinol adsorption by changing the pore size and oxygen content using computational approach. New rhombic OMC models with varied pore size and oxygen content were constructed using Materials Visualizer module. The specific surface area, total pore volume, small angle X-ray diffraction patterns, and resorcinol adsorption capacity results were calculated by Forcite and sorption module in Materials Studio package. The simulation results were validated by the experimental data. Experimentally, the OMCs were synthesized using sucrose as carbon precursor by hard-template method. The tunable pore size (4nm to 15nm) and oxygen content of the OMCs are obtained by adjusting the amount of boric acid as a pore-expanding reagent. The experimental results, such as BET surface area, X-ray power diffraction patterns, and adsorption capacity of resorcinol, were compared with the simulation results. The optimal pore size of OMC for resorcinol removal was found to be 6 nm. The simulation results confirmed that oxygen containing functional group was an important factor for adsorption on OMCs. The improvement of adsorption capacity was not so significant comparing with the influence of specific surface area, since the adsorption process was a more of a physical process rather than a process with chemical interaction.</p>

<p> With the pollution of freshwater sources and the continual increase in freshwater demand due to rapid industrialization and population explosion, the globe is facing an eminent danger of scarcity of freshwater. One way to increase the water supply beyond the hydrological cycle is to reuse and recycle the waste water by developing an onsite recycling/reclamation technology. Such a bench-scale treatment technology was developed to treat the cooling tower blowdown water (CTBW) from the cooling towers of California State University, Long Beach (CSULB). The CTBW was treated by using electrodialysis. </p><p> The main objective of this project was to bring down the level of total dissolved solids (TDS) of the CTBW to lower than 230 mg/L which is equivalent to the TDS level of tap water provided by the Long Beach Water Department. The secondary objective was to regenerate the hydrochloric acid using the waste ions. Two differently configured electrodialysis cells (onechambered and two-chambered cell) were used and their treatment efficiencies were compared. The one-chambered cell successfully reduced the TDS level by upto 48% for three samples tested in the setup. The two-chambered cell achieved the TDS reduction up to 93.4% for the four samples tested in the setup. The study was successful in regenerating 1.42 mol/L concentration of hydrochloric acid. An economic and water savings analysis was also performed. Calculations showed that by implementing this technology, it is possible to save 10,362,564.76 L/year which translates to $10,813.13 in economic savings. The total annual savings were estimated to be $12,984.01. The payback period for the investment in this study was 50 months, thus a profit of $15,949.48 is expected by the end of the equipment life of the setup.</p><p>

<p> Smart materials, within the realm of structural engineering, are mainly used as either sensoric mechanisms or as structural damping mechanisms. For the most part, structural enhancement utilizing smart materials is not seen in main stream structural engineering practices. </p><p> Piezoelectric ceramics and shape memory alloys are two smart materials that are explored. In comparison shape memory alloys have far greater actuation strain (2% - 7%) than piezoelectric (0.08% - 0.11%) ceramics. </p><p> Piezoelectric actuators are employed as surface actuators. Shape memory alloys are also explored in this manner, but the analysis is taken a step further where shape memory alloys are explored as beam and column retrofit elements. </p><p> Because of the low mechanical range of the piezoelectric material, the potential for stress reduction is bound to lower stress applications. The general conclusion for shape memory alloys is that it would be suitable for high stress applications which include main stream steel applications. </p>

<p> Marcellus Shale is one of the world's largest unconventional gas resources. Recent developments in horizontal drilling and hydraulic fracturing enabled efficient and economical extraction of natural gas from unconventional (shale) resources and have led to rapid expansion of natural gas production in the United States. Hydrofracturing generates large volume of flowback and produced water that contains high concentrations of total dissolved solids (TDS), heavy metals, and naturally occurring radioactive materials (NORMs) resulting in significant environmental and public concerns and challenging waste management issues. Ra-226 is the dominant form of NORM and is one of the key challenges for sustainable management of Marcellus Shale wastewater.</p><p> This study is focused on the life cycle of NORMs during natural gas extraction from Marcellus Shale. A rapid method for Ra-226 analysis by inductively coupled plasma mass spectrometry (ICP-MS) was developed to overcome some of the shortcomings of current analytical techniques (e.g., long detection time). The fate of Ra-226 under different scenarios associated with the shale gas extraction, including origin of Ra-226, partitioning in flowback water storage and treatment facilities, and associated solid waste disposal issues were evaluated in this study. This study showed that radium mainly originates from relative rapid shale leaching. High concentration of radium in the Marcellus Shale wastewater can be managed by proper treatment (e.g., sulfate precipitation). However, solid waste generated from treatment facilities or impoundments containing elevated radium concentrations far exceed the limits for disposal in the Resource Conservation and Recovery Act Subtitle D (RCRA-D) landfills. Current practice in landfill management allows the disposal of this solid waste by controlling the Allowed Source Term Loading (ALST) on annual basis. However, if the landfill capacity to accept all the NORM generated from Marcellus Shale gas extraction becomes insufficient, other disposal or beneficial use options for solid waste should be developed. Reuse of radium enriched barite as weighting agent in drilling mud might be a sustainable strategy to reduce the mass of NORM that has to be disposed in the landfills.</p><p> Health risks associated with NORMs were evaluated for several typical scenarios associated with Marcellus Shale gas extraction. Total effective dose equivalent (TEDE) at drilling pads, storage impoundments and landfills are well below the Nuclear Regulatory Commission (NRC) limit for the general public of 100 mrem/yr even under the worst-case scenario assumptions. Workers in the centralized waste treatment facilities might receive excessive TEDE and appropriate measures recommended by NRC should be applied. For example, a safe distance of 5 m is recommended to reduce TEDE to acceptable level. Hence, the key environmental and public health risks associated with NORM brought to the surface by natural gas extraction from Marcellus Shale are from the spills that may contaminate surface and groundwater.</p><p> Overall, this study contributes to the understanding of the fate of NORMs associated with Marcellus Shale gas wastewater management and expands the ability to resolve the environmental concerns associate with NORMs. A novel rapid analytical for Ra-226 measurement by ICP-MS offers an alternative for researchers to quickly analyze environmental samples. The fate of Ra-226 in centralized treatment facilities and storage facilities is important for operators to choose proper management strategy for liquid and solid waste disposal/reuse. The health risk associated with NORM that is assessed in this study will help to resolve the public concern stemming from the high NORM extracted from Marcellus Shale play and provides several options to further reduced its risks.</p>

Thesis (PH.D.) -- Syracuse University, 2007. / "Publication number AAT 3266288"

Thesis (Ph. D.)--University of Sydney, 2008. / Includes tables. Includes list of publications: p. 9. Title from title screen (viewed September 19, 2008). Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy to the School of Chemical and Biomolecular Engineering, Faculty of Engineering and Information Technologies. Includes bibliographical references. Also available in print form.