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Thesis--PlanB (M.S.)--University of Wisconsin--Stout, 1998. / Includes bibliographical references.

Thesis (Ph. D.)--Texas State University-San Marcos, 2006. / Vita. Appendices: leaves 112-154. Includes bibliographical references (leaves 155-170).

Thesis (Ph. D.)--Texas State University-San Marcos, 2006. / Vita. Appendices: leaves 112-154. Includes bibliographical references (leaves 155-170).

Chemical synthesis is closely related to waste minimization. There is no chemical process that does not produce waste. The methods used by industry to deal with this waste is a major environmental concern. This thesis describes the laboratory scale waste minimization and waste treatment strategies for the commercial production process of 4-methyl-3-thiosemicarbazide (MTSC). The production process of 4-methyl-3-thiosemicarbazide was investigated with the aim of increasing the isolated yield of MTSC and at the same time decrease the amount and toxicity of effluent obtained. During this study, parameters were investigated such as the use of excess DIPEA and the temperature of the reaction. Preliminary studies clearly showed that both factors have a significant influence on the final yield of the product. The next part of the investigation was to optimize the two parameters influencing the isolated yield of the MTSC. For this investigation, a multi factorial design was used to determine the optimum conditions in the MTSC yield response. From the results obtained, it was clear that the excess of DIPEA and the temperature of the reaction both need to be high to obtain high yields. These theoretical results were confirmed by results obtained practically, where yields of up 82 % were obtained, but it became clear that even higher yields could be obtained since chromatographic results showed yeilds as high as 90 %. The mass balance of the MTSC synthesis showed a loss of approximately 30 grams per reaction. This loss may have an influence on the final yield. The effluent obtained during the synthesis of MTSC was investigated and a waste treatment protocol was established to reduce the high COD value of the MTSC effluent. The protocol consists of two steps used for the clean up of the effluent. The first being a cooling step; the effluent was cooled at 0oC to induce precipitation of a solid, consisting mostly of MTSC. The second step is a high pressure wet oxidation of the effluent with oxygen in a high pressure reactor. The remaining compounds in the effluent were oxidized, resulting in another precipitate, consisting mostly of sulphur. After the oxidation the COD value of the effluent was decreased by 98 % to a value of 0.4 %. The MTSC present in the precipitate obtained after cooling could be isolated and purified, to add to the yield of the synthesis. The sulphur obtained during the oxidation could also be isolated and reused, or sold to prevent it from contaminating the environment.

On August 31, 1992, Quality Printing Circuits, a circuit board manufacturing plant in Phoenix, Arizona, burned to the ground. The fire lasted approximately eight hours, creating a thick, black smoke that blew into the surrounding community. Emergency evacuation was erratic and since no air samples were taken during the fire, community exposure levels were unknown. Immediately afterwards, residents reported health problems but government studies on the community were unable to link reported health problems and the fire. Eight months after the fire, a local advocacy group performed a health study on the community. The 690 people surveyed reported symptoms such as asthma, blurred vision, vomiting, hair loss, rashes, and extremity numbness. The survey was never analyzed and the case was closed. Community members continued to report health problems and five years after the fire, the US Environmental Protection Agency reopened the case. They performed two sampling studies but results found that chemical levels were below allowable exposure levels. This thesis contains three chapters that investigate the political, health, and scientific issues related to the QPC fire. The scientific chapter uses the EPA's ISCST3 dispersion model and a mixed-box model, to approximate community exposure concentrations and compare them to allowable human exposure levels. Results of the ISCST3 model show that four (hydrogen chloride, polycyclic aromatic hydrocarbons, Acrolein, and naphthalene) of the twenty chemicals modeled were above government allowable concentrations. Inhalation exposure to these chemicals causes similar symptoms as those reported by residents. The health-focused chapter characterized health symptoms reported in the 1993 health survey. Results found that symptoms experienced by residents were similar to those documented in other studies of exposure to chemical smoke. The study also found that residents living closest to QPC reported a greater number of symptoms than residents living further away. The political chapter analyzed the debate as to whether QPC officials and government agencies took the steps needed to protect the exposed community during and after the QPC fire. What became evident was that a significant conflict existed between the interests of residents involved in the QPC fire and the government agencies responsible for protecting them. / Graduation date: 2004

Thesis (MA)--University of Montana, 2009. / Contents viewed on April 30, 2010. Title from author supplied metadata. Includes bibliographical references.

Hazardous materials data from business and industrial chemical information and incident databases were analyzed to study the types of chemicals located in Linn, Benton, and Lincoln Counties, Oregon. Federal and Oregon Department of Transportation data were analyzed to study traffic patterns and truck and railroad traffic levels. Results indicate more than 2,000 chemical products are reported by businesses and industries in the three counties, with about 1,000 hazardous ingredients. The primary hazard Classes for these chemicals are flammable fuels, corrosives, and poisonous materials. Diesel, heating fuel, gasoline, and related fuels comprised more than 50% of the materials transported in the study area. A Geographic Information System (GIS) was used to input industrial and business locations of hazardous materials, historic hazardous materials incidents, traffic densities, population centers, and traffic network intersections. These metrics were modeled as risk factors for potential hazardous materials transportation risks. For Benton County, these factors were combined with population density and critical facilities themes to provide the basis for overlay and proximity analysis for the purpose of facilitating emergency planning and to foster public awareness. Located on the Interstate 5 corridor, Linn County uses and transports a greater variety of hazardous materials than Benton or Lincoln Counties. For example, fifty-one of fifty-five extremely hazardous substances found in the three county area were reported in Linn County, with 24 reported in Benton County, and 6 reported in Lincoln County. Data from Oregon Department of Transportation were extracted to assess accident and traffic patterns and integrate these risk factors with hazardous materials information. One federal and one state database reporting hazardous materials incidents were analyzed. Although traffic increased on study area roads more than 25% in the last decade, two hazardous materials incidents databases did not indicate an increasing number of emergency spill responses. The Oregon State Fire Marshall's incident database indicated an average of 34 per year between 1988-1997. Linn County averaged 18 per year during this time period, Benton County averaged 13, and Lincoln County averaged 3. Fuels were the primary chemical type responded to. The federal Hazardous Materials Information Reporting System database reported 40 incidents in the highway category and 11 railway incidents. Both types of incidents were dominated by corrosive materials in this database, which does not include fuels as defined hazardous materials. Traffic data on the roads used for hazardous materials transport show much higher traffic densities near intersections with other major roadways and in urban areas. Incident reports followed this pattern, primarily occurring in the major cities and towns of the three counties. Estimated daily numbers of trucks carrying hazardous materials ranged from 6 per day on the coastal portion of Oregon 34, to almost 700 on the section of I-5/99E between Albany and the Linn-Marion County border. Rail data studied indicate the highest quantities of materials designated hazardous were also transported on the main north-south corridor of Linn County, implicating this central area in the three counties has the highest density of the risk factors studied. / Graduation date: 2000

A variety of hazardous organic compounds are present in leachate from landfill sites that accept medical and industrial chemical waste. Most of these compounds find their way into nearby streams, rivers and dams, posing a threat to the ecosystem. In the present work two hazardous organic compounds, namely, m-xylene and 2-chloroethanol were chosen to react with ozone gas at different experimental conditions. The ozone initiated oxidation of m-xylene and 2-chloroethanol in solvent free conditions were investigated as a function of time. Gas chromatographic analysis of ozonated m-xylene, showed an increase in the conversion of substrate from about 1 % after 3 hours to about 14 % after 24 hours. Some of the ozonation products identified were formic acid, acetic acid, 3-methylbenzylalcohol, 3-methylbenzaldehyde and 3-methylbenzoic acid. The presence of acetic acid, ethyl acetate or acetone during ozonation significantly improved the percent conversion of m-xylene relative to similar products obtained under solvent free conditions. The presence of activated charcoal during ozonation of m-xylene showed marginal improvement in percent conversion compared to solvent free ozonation. The oxidation of 2-chloroethanol was followed by monitoring the consumption of the halogenated organic substrate which showed an increase in conversion from about 2 % after 3 hours to about 46 % after 12 hours. Ozonated products contained a mixture of acetaldehyde and acetic acid. It was also found that the ozonation of 2-chloroethanol yielded quantitative amounts of chloride ions. The percent conversion of 2-chloroethanol in the presence of acetic acid and ethyl acetate were higher than those under solvent free conditions. The use of activated charcoal during ozonolysis of 2-chloroethanol showed a significant increase in percent conversion of the substrate. Since 2-chloroethanol has a higher solubility in water than m-xylene the effects of solution pH, activated charcoal and hydrogen peroxide on ozone initiated reactions were studied. Solutions of 2-chloroethanol maintained at pH level 4 and 7 showed marginal changes in percent conversion compared to ozonation alone, however percent conversion improved significantly when the pH of the solution was increased to 10. The ozonation of 2-chloroethanol in the presence of 5 % hydrogen peroxide in water at pH levels 4 and 7 showed marginal changes in percent conversion compared to ozonation alone, however, percent conversion and product yields improved significantly, when the pH of the solution was increased to 10. Increasing the strength of the hydrogen peroxide in the reaction mixture from 5 % to 10 % had very little effect in the percent conversion of 2-chloroethanol and product formation. Based on the experimental findings the overall reaction mechanism for the reaction of both m-xylene and 2-chloroethanol with ozone is described. / Thesis (M.Sc.)-University of KwaZulu-Natal, Westville, 2010.

Thesis (M.S.)--Tufts University, 2000. / Cover title. "Submitted in partial fulfillment of the requirements for the degree of Master of Science in Civil and Environmental Engineering Tufts University." "May 2000."