Partner: HN-FTB, THIES, CHT
Dyeing processes are considered as very water intensive. E.g., for one kilogram of reactively dyed cotton, usually between 60 and 80 Liter of freshwater are needed. Chemicals, machine types and ages play an important role in the consumption of water and the effects on wastewater in the textile industry. Innovations on textile machinery and in dying chemicals make it possible to reduce water consumption and improve wastewater quality. M7 is investigating different approaches to reduce water consumption and effluents by changing the current use of process chemicals and technologies in textile dyeing processes. The goal is to provide practical data on the effectiveness of new dye technologies and chemicals. Processes are identified which achieves best possible results with less water use and less polluted wastewater.
Test (P1 – P4) were carried out at THIES using dyestuff chemicals of CHT (see chart above). The first results of lab dying processes confirm remarkable water savings. Under special conditions, a 50% water use reduction appears possible. As a positive side effect, the process change causes a reduction of > 40% process time. Colorimetric methods were applied to define differences in color (ΔE value, CMC/D65), lightness, saturation, hue and strength compared to the standard trial P0. Most common color fastness test methods like fastness to perspiration, washing, and rubbing had been conducted serving as an industrial quality management and controlling tool. The present outcome does not yet fulfil all requirements given by industry regarding color fastness and color outcome. Improvements are possible and are planned to get demonstrated in upcoming trials. During all studies, process water drains get collected for analysis of the dye fixation rate to show the increased textile pick-up of improved kind of dyes used in some trials.
We hope to show up practical ways how the use of advanced dyestuffs does reduce the water use and the wastewater quantity by fulfilling all industrial requirements – in Pakistani textile manufacturing and textile industry worldwide.