Textile finishing and dye manufacturing industries discharge wastewater which has become a major environmental concern. In many countries, the legal stipulations regarding discharge of contaminated wastewater have been reinforced and the discharge fees continue to escalate. To this end, major international clothes companies are implementing a new standard of requirements that are often higher than the local legislation requirements.
Complexities of Removing Dye from Wastewater
In a typical dyeing process, the dye is dissolved into the process water, which is later released as effluent without removing the dye. This effluent includes high concentration of additives such as surfactants, dyestuff, etc. that are usually made up of organic compounds with a complex structure. These dissolved dye organic compounds are resistant to oxygen, acids, bases, and light as these are the preferred properties of the dyed clothes. Using traditional methods for treating textile wastewater would prove ineffective here because these organic compounds exhibit poor biodegradability.
The dissolved organic dye compounds are the main environmental concern of textile wastewater as some of them are aromatics and believed to be carcinogenic i.e. substances that cause cancer.
Ozone for Removing Dye from Wastewater
Figure 1. Different doses of ozone used to remove dye from the same textile wastewater.
High concentration ozone helps in breaking down the dissolved organic dye compounds and thus reduces the amount of color (Figure 1). This method considerably helps in improving the biodegradability of the wastewater. According to Primozone, a company that provides safe and customized ozone solutions for water treatment, the most efficient way to remove dissolved dye is to use a combination of ozone, biology, and filtration.
A combination of ozone, biology, and filtration can be effective in removing harmful organic compounds from wastewater. The dye manufacturing and textile finishing industries can adopt this technique to reduce their impact on the environment.
This information has been sourced, reviewed and adapted from materials provided by Primozone.
For more information on this source, please visit Primozone.