Optimization of a Textile Effluent Treatment System and Evaluation of the Feasibility to Be Reused as Influents in Textile Dyeing Processes

Abstract

Textile effluents derived from azo-reactive dyeing processes represent a severe problem for aquatic ecosystems and human health. The large amounts of water used in this process and the poor quality of the discharges urge the need to develop treatment systems that involve reusing treated water. In this research, we present the optimization of a feasible, simple, and efficient treatment system that improves the quality of the effluents from the cotton fabric dyeing process. Through the characterization of the influents and effluents, we have identified seven parameters that have allowed the optimization of the treatment. Analytical techniques, such as nephelometry, EDTA, gravimetry, and BOD5, among others, and specialized equipment, such as the spectrophotometer, have been used for these purposes. The results showed that using combustion gases in the neutralization stage and new flocculant-coagulant reagents improved parameters, such as pH, total solids, hardness, and conductivity. The quality of the effluents thus obtained allowed their reuse only in the stages before the dyeing bath without affecting the final quality of the cotton fabrics in dark colors. This effort implies savings in water and supplies, and opens the door to future research on the treatment of textile effluents that help improve the environmental conditions of our region.