Critical analysis of the characteristics of industrial effluents from the textile sector in Brazil

Abstract

High water consumption and the consequent generation of large volumes of effluent are two of the most damaging characteristics of textile industries in the socio-environmental context. Water is used in practically all stages of the beneficiation process, generating effluents of heterogeneous composition, containing complex and recalcitrant compounds. The present work had as objective to make a survey and analysis of the data of textile effluents from Brazil obtained through extensive consultation to the literature. It was noticed that the analyzed characteristics varied significantly between the effluents, highlighting the high concentration of organic matter, through the parameters Chemical and Biochemical Oxygen Demands (COD and BOD, respectively). Effluents from industries generally had a higher concentration of organic matter than those from industrial laundries. There is no linear correlation (R2 < 0.8) between COD and BOD5 data. The existence of such correlation would allow estimating BOD5 through COD, as a way to expedite the characterization of wastewater. Through values above 3.5 for the COD/BOD5 ratio, it was observed that most of these effluents have low biodegradability. Due to this aspect, the physical-chemical process of coagulation-flocculation has typically been the main stage involved in their treatments. However, biological processes have also been used to contribute to the removal of biodegradable organic matter.