Influence of Cotton Bleaching Methods on the Parameters of Generated Textile Industrial Wastewater

The environmental impact of industrial wastewater after bleaching requires special attention to prevent the pollution of aquatic ecosystems. The aim of this study was to compare the effluent parameters obtained after using a traditional bleaching method and an alternative enzymatic bleaching method in order to assess their possible environmental impacts. In the classical bleaching method, NaOH and H2O2 were used, and in the alternative method, pectinase enzyme, H2O2, and sodium carbonate were used as the bleaching agents. The bleaching process was designed by determining the optimum amount of pectinase enzyme, the optimum temperature, and the optimum amount of peroxide. The whiteness of the treated cotton yarns was also evaluated. The different bleaching processes were analyzed and evaluated in terms of the wastewater discharged, the pH, chemical oxygen demand (COD), total dissolved solids (TDS), total suspended solids (TSS), and conductivity. These data show that the use of the pectinase enzyme allows us to obtain much lower COD and TSS values compared to those obtained using traditional bleaching. At the same time, the use of the proposed enzymatic bleaching method reduces the environmental impact since lower concentrations of pollutants are obtained in the effluent. Therefore, the pretreatment of wastewater may require the selection of a simpler and more environmentally friendly technology, such as enzymatic bleaching.