Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1993. / Vita. Abstract. Includes bibliographical references (leaves 79-88). Also available via the Internet.

No description available.

No description available.

In this research, the ability of anaerobic and aerobic biological sludges to reduce and stabilize azo dye compounds was studied. Synthetic dye solutions and an industrial textile wastewater were both treated using anaerobic and aerobic biomass, separately and in sequential step-treatment processes. The primary objective was to reduce the wastewater color to an intensity that complies with the Virginia Pollutant Discharge Elimination System (VPDES) permit level. This level is set at 300 American Dye Manufactures Institute (ADMI) units. Further objectives were to achieve reductions in the total kjehdal nitrogen (TKN) and total organic carbon (TOC) in the wastewater. Anaerobic and aerobic treatment systems were both effective in reducing the wastewater color; however, anaerobic treatment generally produced the greatest color removal. Anaerobic/aerobic (ANA/AER) sequential step-treatment provided the best reductions in ADMI color, TKN and TOC. Anaerobic/aerobic/anaerobic/aerobic (ANA/AER/ANA/AER) sequential step-treatment did not yield greater reductions in ADMI color, TKN, or TOC as compared to ANA/AER sequential step-treatment. / Master of Science

A pilot-scale system was constructed at the Martinsville Publicly Owned Treatment Works (POTW) in Martinsville, Virginia, to evaluate an anaerobic/aerobic treatment scheme for removal of color from textile dye waste waters mixed with municipal sewage. Treatments were evaluated with and without addition of a reducing agent (thiourea dioxide) after anaerobic treatment utilizing 6 and 12 hour anaerobic hydraulic retention times (HRT). Polymer treatment of the aerobic effluents and toxicity of the wastewaters to Ceriodaphnia dubia and Pimephales promelas were studied. In addition, the benefits of polymer treatment of anaerobic effluent, prior to aerobic treatment, were evaluated in a lab-scale system utilizing continuous flow biological reactors (CFBRs). Wastewater samples were collected throughout the treatment schemes and analyzed for: color, total organic carbon (TOC), 5-day biochemical oxygen demand (BODs), chemical oxygen demand (COD), total phosphorus, sulfide, sulfate, total Kjeldahl nitrogen (TKN), ammonia, nitrate, chloride and oxidation-reduction potential (ORP). Nearly 50% color removal was observed during anaerobic treatment with a 12 hour HRT, with a total system color removal, including subsequent aerobic treatment, of about 53%. / Master of Science

The current waste management system of Post Consumer Textile Waste (PCTW) in Sweden leads to vast amounts of incinerated or exported textiles. The amount of PCTW reused or repurposed within the country is small in comparison to the amounts of textile products consumed every year. Hence, there is an observed problem in terms of low value creation from textile waste. A system that allows for more textiles to be kept and reused in Sweden could create more economic value in a resource-efficient way. Hence, the purpose of this thesis is to investigate value creation from PCTW for reuse and redesign in Sweden, and to establish a framework for the antecedents of value creation in reverse textile value chains. A pre-study was conducted to map the PCTW industry structure, and served as the basis for sampling cases. Data collection consisted of multiple case studies from 4 charity organisations, 3 clothing brands and 3 redesign brands. The interviews were performed in a semi-structured manner in order to discover the state-of-art in value creation and to identify the key enabling attributes. The findings were analysed to adjust the deductive framework to the textile industry context. Results and findings shows that the state-of-art for value creation among the selected cases varies depending on its mission. Charity organisations are facing a new competition of resources from clothing brands, who have realised a potential of new differentiation by engaging in value creation from PCTW. This has led to a new mind-set among the charity organisations to work more strategically in all their activities. Redesign brands are a relatively new actor and want to work symbolically with redesign to communicate the values in textile materials. Enablers and disablers to value creation from PCTW were found in the interviews and led to the development of an empirical framework. As a whole, this thesis provides rich descriptions of the current preconditions and challenges within the field. Furthermore, it presents a framework for the antecedents of value creation along the recovery processes involved in reuse and redesign value chain. The empirical framework confirms the themes in the theoretical framework, and concludes that there is a set of generic antecedents for value creation in reverse textile value chains. However, there are also category specific antecedents, which need to be considered. The specific experiences of one actor category might as well be valuable knowledge to another, which is why increased collaboration is suggested to enhance value creation from PCTW.

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1992. / Vita. Abstract. Includes bibliographical references (leaves 154-160). Also available via the Internet.

Thesis (Ph. D.)--University of Texas at El Paso, 2009. / Title from title screen. Vita. CD-ROM. Includes bibliographical references. Also available online.

The feasibility of the excess lime process for color removal from textile dye wastes was evaluated. The lime dosages were optimized by using anionic, cationic, and nonionic polyelectrolytes as coagulant aids. The effect of the process on the removal of organic pollutants was determined. The time interval between coagulant additions was analyzed. Color reductions of at least 94 per cent were obtained by the lime and lime-polyelectrolyte processes. The lime dosage of 980 to 1,060 ppm was decreased by at least 30 per cent using 5 ppm polyelectrolyte dosages. The processes reduced the Total Organic Carbon concentration by 73 per cent approximately, the Chemical Oxygen Demand by 50 per cent, and suspended solids by about 85 to 90 per cent. The excess lime process was more efficient in removing organic matter than the lime-polyelectrolyte processes, and also incurred the least chemical coagulant cost. The excess lime process was most effective at 30 minutes flocculation and 30 minutes settling. The lime-polyelectrolyte processes were more effective when the polyelectrolyte was added after about 30 minutes lime flocculation and settled for 5 minutes. The lime-polyelectrolyte processes produced a floe which settled rapidly. The volume of sludge produced was about 8.1 to 12.8 per cent, resulting in a sludge to supernatant ratio range of 1:7 to 1:11. The lime-polyelectrolyte sludge volumes were usually higher than the lime sludge volumes. / Master of Science

The compound p-(2-hydroxyethylsulfone) aniline was isolated from a reduced solution of a fiber-reactive azo dye. The identity and purity of this product was assessed through elemental composition analysis, high performance liquid chromatography (HPLC), gas chromatography/mass spectroscopy (GC/MS), and nuclear magnetic resonance spectroscopy (NMR). The toxicity of this purified compound was measured with Microtox and Daphnia pulex tests. Microtox tests were also performed on compounds with similar structures to p- (2-hydroxyethylsulfone) aniline. Wastewater samples containing textile dye wastes from a Publicly Owned Treatment Works (POTW) that treated textile dye wastes were monitored for the presence of p-(2-hydroxyethylsulfone) aniline using HPLC. Microtox testing was performed on these samples. Analytical tests confirmed the identity and purity of p-(2-hydroxyethylsulfone) aniline as the reduced product. Microtox tests revealed the concentration at which 50% of the light output was reduced (EC₅₀) after 5 minutes of exposure was 12.8 mg/L. Daphnia pulex testing yielded the concentration which was lethal to 50% of the tested organisms (LC₅₀) to be 113 mg/L. The 5-minute Microtox EC₅₀, values of aniline, sulfanilamide, 2-hydroxyethylsulfone, and 4-ethylaniline were 106.7, 8.15, >80, and 2.05 mg/L, respectively. The reduction product, p-(2-hydroxyethylsulfone)aniline, was not detected in textile-containing wastewater from the Martinsville POTW. The Microtox EC₅₀, for this wastewater, ranged from 6.05 to >75 mg/L. / Master of Science