The textile industry in South Africa is a significant contributor to the chemical load that public wastewater treatment plants have to process, and the discharge of toxic substances, especially to the aquatic environment. In order to address this issue at factory level, the processes at a textile plant, JMV Textiles were chosen for investigation into the possibilities of minimization of discharges of harmful substances into the environment. The study followed the principles of cleaner production, and the processes that were investigated and revised were: The conventional peroxide bleaching process employed a peroxide stabilizer that did not biodegrade easily. The bleaching process was changed, so that the prevailing conditions in the fabric and dyebath facilitated bleaching without the addition of peroxide stabilizer, and also reduced the alkali and energy requirements. Polyester‐viscose fabric was pretreated by bleaching with hydrogen peroxide, which seemed to be unnecessarily rigorous, because polyester and viscose, unlike natural fibres, are relatively clean and have good whiteness in comparison with natural fibres. The proposed alternate pretreatment was a scour with detergent and alkali. The pretreatment for all polyester‐cotton fabrics was also a hydrogen peroxide bleach. Due to the ability of medium and dark shades to mask the natural tint of cotton fibres, a simpler alternate pretreatment, consisting of an alkaline scour with sequestering agent, was trialled. An unacceptable proportion of the dyeings on polyester was rejected for dye‐stains and dye‐marks. A possible solution exploited the properties of using the finishing auxiliary chemical to alleviate dye‐stains and dye‐marks during the dyeing stage, instead of using the chemical after dyeing. The highly toxic carrier that was used to facilitate level dyeing of polyester fibres that had unacceptable variation in their dyeing properties, was replaced by a less toxic carrier. The formulation for dyeing polyester was simplified to eliminate the auxiliary chemicals that were not essential to the dyeing process. Pale reactive dyed shades on cellulose and polyester‐cellulose were washed off only with hot water instead of detergent. The revised procedures consequential to the study, offered significant environmental benefits by reducing the concentration and volume of effluent produced, substituting a highly toxic carrier with a less toxic one and saving energy and water. Implementation of the suggested changes also offered financial benefits. The management of the factory, however, accepted and implemented some changes, but wanted further investigations for others and a phased approach to the other suggested changes.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:nmmu/vital:10454 |
| Date | January 2013 |
| Creators | Dayla, Mackraj |
| Publisher | Nelson Mandela Metropolitan University, Faculty of Science |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis, Masters, MSc |
| Format | 116 leaves, pdf |
| Rights | Nelson Mandela Metropolitan University |
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