Textile Wastewater Treatment Creates High Levels of Toxic Compounds

Textile wastewater treatment processes can produce high levels of toxic byproducts, including chloroform and bromoform. These byproducts pose occupational health hazards and may have unknown environmental effects. Researchers at the University of Massachusetts Amherst published these findings in the Journal of Hazardous Materials.

The textile industry generates up to 20% of the world's wastewater. Previous research indicates that textile wastewater can harm the environment, crop production, and human health. Companies often use electrochemical methods to treat this wastewater. This process involves using electricity to break down dyes. Sodium chloride, or table salt, is added to increase water conductivity. This reduces energy costs and speeds up dye degradation.

Sean McBeath, an assistant professor at the Riccio College of Engineering at UMass Amherst, expressed concern about the byproducts formed. His Water, Wastewater, and Electrochemical Technologies (WWET) Lab typically studies drinking water treatment. Their work has shown that chloride in electrochemical reactions forms reactive chlorine species. These species can create harmful byproducts, also known as disinfection byproducts in drinking water treatment.

The study investigated Azo dyes, which comprise 50% of market dyes. Researchers found chloride-based toxic byproducts at hundreds of parts per billion. They also tested textile dyes containing bromine. This treatment generated bromoform at 526 parts per billion (ppb).

The U.S. Environmental Protection Agency (EPA) regulates these compounds in drinking water. The cumulative limit for trihalomethane species, which include chloroform and bromoform, is 80 ppb. The concentrations found in the study were three times higher than the EPA limit for Azo dyes. When bromine was present, concentrations exceeded ten times the EPA regulatory limit.

The study suggested three mitigation options. One option is to use sodium sulfate instead of sodium chloride. This alternative salt does not generate the same harmful byproducts but slows the treatment process. Another option involves using novel catalysts to speed up reactions. These catalysts are costly and still produce some byproducts. A third option is to implement worker protections, such as proper ventilation, in textile factories. Future research will explore pre-treatment steps and other potential byproducts.