Pretreatment is a common approach for removing color and reducing the organic load of textile dyeing and finishing wastewater. Subsequent aerobic treatment is often employed to complete organic removal as well as remove toxicity and metals. The wastewater from the textile dyeing and finishing industry studied was not treated efficiently and often failed effluent toxicity and metals tests. In this research project, various pretreatment alternatives were studied in an attempt to identify the most efficient and economical method(s). Also, aerobic, biological treatment was performed in bench-scale reactors to determine the biological kinetic coefficients of the wastewater so that the overall efficiency and performance of the biological treatment system might be improved. Effluent toxicity of the wastewater was also evaluated in hopes that improved treatment efficiency would yield subsequent improved effluent toxicity. The performance of a sequencing batch reactor was compared to that of the continuous-flow reactors. In regard to pretreatment with various polymers, coagulation with a blend of inorganic aluminum and a polyamine (AL220, Polymer Systems, Inc.) produced the most economical and efficient results. Subsequent addition of an anionic polymer improved the settling characteristics of the chemical flocs. Color removal ranged from 71-90% and DOC removal averaged 25% with AL220 doses between 400-600 mg/L. Increased sludge ages (θ_c) of the continuous-flow reactors produced improved removal efficiencies. Sludge ages of 8-30 days resulted in an average of 55-68% COD removal. Kinetic analysis produced values of 0.032 d⁻¹ and 0.619 for k_d, and Y, respectively. K_s and k could not be determined accurately. This difficulty was attributed to possible inhibitory effects and a residual, biorefractory COD that was not quantified in this study. The SBR, operated with a cycle time of one day and an average MLSS concentration of 4,266 mg/L, achieved an average 69% COD removal and 59% color removal. Addition of nutrients did not appear to improve these efficiencies. Settling characteristics of the sludge were excellent. Preliminary acute toxicity testing of the SBR effluent and effluent from the 8 day θ_c reactor produced encouraging results. Subsequent chronic toxicity testing of the 15, 20 and 30 day θ_c reactors yielded a maximum No Observed Effect Concentration of 50-75%. / Master of Science

With the advent of polyester fibers, disperse dyes, with complex chemical carriers and surfactants have been introduced. These dispersing agents inhibited chemical treatment and passed through biological facilities untreated. Therefore, it was the purpose of this study to ascertain whether chemical treatment with polyelectrolytes could achieve an economical treatment. The study consisted of the evaluation of flocculation performance (turbidity, chemical oxygen demand, and color reductions) for treatments with alum alone and alum with polyelectrolytes. A univariant search technique was used to optimize the flocculation performance with respect to the three parameters, pH, alum concentration, and polyelectrolyte concentration. The results of the alum treatment revealed that the chemical oxygen demand reduction was inadequate, although turbidity and color reductions were sufficient, to permit disposal of the effluent to the stream. When cationic polyelectrolytes were used with alum the results were greatly improved compared to alum. Reductions of turbidity, chemical oxygen demand, and color greater than 80 per cent were attained with two cationic polyelectrolytes. The flocculation performance with anionic polyelectrolytes was inferior to treatment with alum and alum with cationic polyelectrolytes. The floc was faster settling for all polyelectrolyte treatments. The volume of sludge in alum treatment was two to 2.5 times greater than for treatment with polyelectrolytes. Considering the present value determinations, aerated lagoons were the least expensive investment and would be the obvious means of treatment. However, if restrictions such as color reduction were imposed, chemical treatment with polyelectrolytes may be justified. / Master of Science

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

Dissertation (PhD)--Stellenbosch University, 2003. / ENGLISH ABSTRACT: At the beginning of the 1990s, the South African textile industry faced many challenges, including the dismantling of protective barriers, requiring firms to adapt to increased foreign competition in the local and global markets. Many opted for investment in new technology. This study set out to analyse the behaviour of South African textile firms in the process of introducing new technology in pursuit of competitiveness. The analysis was conducted following the evolutionary approach in economics (discussedin Chapter 2). This approach incorporates time, pays attention to the deliberate actions of firms to shape their environment, as well as persistent diversity amongst firms. This study asked two broad questions. First, what were the major trends in textiles regarding technology, demand-side factors, the trade regime, etc.? (Chapter3). Chapter 3 sets the scene for the rest of the study in that it illustrates how the competitive environment of textile firms has changed and argues that the aggregate picture is often not a true reflection of the dynamics of the industry, thus paving the way for micro-level analysis of firms and institutions. Secondly, what were the subsequent responsesby textile firms and institutions to these changes?This question is investigated for the global textile industry (Chapter 3), the South African, Italian and Mauritian textile industries (Chapters 4 and 5), and for specific firms in the South African textile industry (Chapters 6 and 7). Institutions play an important role in shaping the development of industries, just as firms in an industry may influence institutions. The role of institutions in the South African textile industry is considered in Chapter 5, which serves as background to Chapter 6, where we enquire about the significance of these institutions from the firms' perspective. The central focus of Chapter 6, however, is on the processof acquisition and implementation of new technology in South African textile firms. The implications of this process for other strategies, organisational processes, competencies, and routines are also analysed. Basedon the outcome of the firm-level analysis, three categories of firms are distinguished, namely leading firms, moderate adapters, and laggards. Using the characteristics of the firms in each category, we select three firms to pursue further in case studies. Chapter 7 presents the results of these case studies. Although the main focus of our study is on the implementation of new technology, we want to illustrate in this chapter how the successof this process critically depends on factors such as an appropriate organisational structure, the competencies of management and labour, as well as the institutions in the industry. We further highlight the important role that individuals, such as entrepreneurs, play in shaping the paths of firms, their relationships with institutions, suppliers, and customers, and even the structure of the industry. We conclude that investing in new technology is a necessary but not sufficient strategy for successful rejuvenation of firms in a mature industry. Complementary changes, such as in organisational structure, use of human resources, and supply-chain relations, are of crucial importance, too (Chapter 8). / AFRIKAANSE OPSOMMING: Aan die begin van die 1990s het die Suid-Afrikaanse tekstielbedryf menige uitdagings (soos die aftakeling van beskermingsmaatreëls) in die gesig gestaar, wat hulle gedwing het om meer doeltreffend in die plaaslike en globale markte te word. Hierdie studie ontleed die gedrag van ondernemings in die tekstielbedryf in die proses van verkryging en implementering van nuwe tegnologie ten einde mededingingendheid te bevorder. Die studie volg die evolusionêre benadering, wat tyd inbou en aandag skenk aan doelbewuste aksies deur maatskappye om hulle omgewing te beïnvloed, asook volgehoue diversiteit tussen maatskappye (Hoofstuk 2). Die studie het twee breë vrae gestel. Eerstens, is daar gekyk na die belangrikste tendense t.O.V. tegnologiese veranderinge, vraagkantfaktore, handelsregulasies, ensovoorts, in die tekstielbedryf (Hoofstuk 3). Hoofstuk 3 skets die struktuur vir die res van die studie deur die veranderinge in die omgewing waarbinne tekstielmaatskappye meeding uit te lig, maar ook deur aan te toon dat die globale prentjie nie altyd 'n ware refleksie van die dinamiek van 'n nywerheid is nie, omdat soveel diversiteit daardeur verbloem kan word. Hierdie argument is dus ten gunste van verdere mikrovlak analise van ondernemings en instellings. Tweedens word gevra watter reaksies op hierdie veranderinge daar van ondernemings en instellings se kant af was. Hierdie vraag word ondersoek vir die globale tekstielbedryf (Hoofstuk 3), die Suid-Afrikaanse en Italiaanse tekstielbedrywe, asook die bedryf in Mauritius (Hoofstuk 4 en 5). Verder word die vraag vir spesifieke Suid-Afrikaanse ondernemings in Hoofstukke 6 en 7 bestudeer. Instellings speel 'n belangrike rol in die ontwikkeling van nywerhede, net soos ondernemings in nywerhede ook instellings kan beïnvloed. Die rol van instellings in die Suid-Afrikaanse tekstielbedryf word in Hoofstuk 5 behandel, deels as agtergrond vir Hoofstuk 6 waar die belangrikheid van instellings uit die ondernemings se oogpunt van naderby beskou word. Die hooffokus van Hoofstuk 6 is egter die verkryging en implementering van nuwe tegnologie in Suid-Afrikaanse tekstielmaatskappye. Die implikasies wat hierdie proses vir ander strategieë, organisatoriese prosesse, vaardighede en roetines van die ondernemings inhou, word ook bestudeer. Voortvloeiend uit die ondernemingsvlakanalise, word drie kategorieë van ondernemings onderskei, naamlik leiers, middelmatige aanpassers en sloerders. Op grond van die kenmerke van die ondernemings in elkeen van die kategorieë is drie maatskappye vir verdere ontleding in gevallestudies gekies (Hoofstuk 7). Alhoewel die hooffokus van die studie die implementering van nuwe tegnologie is, illustreer ons ook in Hoofstuk 7 dat die proses sterk beïnvloed word deur faktore soos die organisatoriese struktuur, die vaardighede van die bestuur en werkers, sowel as die instellings in die industrie. Ons beklemtoon verder die belangrike rol wat individue, soos entrepreneurs, speel t.O.V. die ontwikkelingstrajek van ondernemings, sowel as die verwantskappe wat ondernemings met verskaffers, instellings en klante opbou. Aksies deur individue beïnvloed in die finale instansie ook die struktuur van die industrie. Ons gevolgtrekking is dat investering in nuwe tegnologie 'n noodsaaklike maar nie voldoende strategie vir die suksesvolle vernuwing van ondernemings in 'n volwasse nywerheid is nie. Komplementêre veranderinge, byvoorbeeld in die organisatoriese struktuur, die benutting van arbeid, en verhoudings in die verskaffingsnetwerk, is ook van kernbelang.

Yuan Yu-mei Shirley. / Title also in Chinese. / Summary in Chinese. / Thesis (M.B.A.)--Chinese University of Hong Kong, 1980. / Bibliography: leaf 194.

by Cheung Lai-Kuen Hermia, Leung Kwok-Choi Andrew, Mok Wai-Hin Peter. / Thesis (M.B.A.)--Chinese University of Hong Kong, 1987. / Bibliography: leaves 58-59.

Thesis (M. Phil.)--University of Hong Kong, 1999. / Includes bibliographical references.

Thesis (M. Soc. Sc.)--University of Hong Kong, 1996. / Includes bibliographical references (leaf 119-126).

Thesis (Ph. D.)--University of California, Berkeley, 1987. / Abstract. Includes bibliographical references (leaves 142-157).

Thesis (M.Soc.Sc.)--University of Hong Kong, 1996. / Includes bibliographical references (leaves 119-126) Also available in print.