engleski

Computer Control Of Water Recovery And Reuse In Dyehouse

The reuse of water in dyehouse is now quite a widespread process. However the feasibility of water reuse depends on the used dye, auxiliaries, purifying process. In typical dyeing processes, 50-100% of the dye is fixed on the fibre, and the unfixed dyes discharged in spent dye-baths or in wastewater from subsequent textile-washing operations. Dyeing with reactive dyes, however, provokes serious environmental concerns. The process requires large amounts of salt to assist the dye exhaustion and logically salt have very important place in waste water purifying. This study takes the textile industry and evaluates the possibilities of water recovery and reuse in dyehouse. To realize water recycling process in dyehouse, analysis of whole technological chain has to be completed. Experience with computer control water reuse in the reactive dyeing based on conductivity measuring was presented. It was concluded that purifying process by coagulation / flocculation process, in combination with adsorption using active carbon, made possible water and salt reuse. Two reactive dyestuffs were chosen as model dyes: 1. monofunctional C.I. Reactive Blue 19 - vinilsulphone, anthraquinone chromophore and 2. bifunctional - monochlorthreazine / vinilsulphone, azo chromophore. The optimum coagulant and flocculant concentration was defined regarding measuring concentration of residual dyestuff, pH, conductivity, COD and TOC based on using process flow diagram (PFD). Results obtained indicate satisfactory degree of decolourising and purifying regarding the suggested quality of water that can be let out in to rive, the recycled or reused in new dyeing process.

textile waste water ; reactive dyestuff ; coagulation ; flocculation ; conductivity ; COD ; TOC

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