The clothes industry is a major source of income for many countries. But before textiles can be turned into garments, they need to be dyed. Wastewater from dyeing processes is leading to environmental pollution. The IAEA supports the use of a radiation technology to address this issue.
Cotton is an important cash crop for Brazil. In 2014 the country produced over one and half million tonnes, making it one of the world’s leading cotton producers and exporters.
The country’s flourishing textile and clothing industry benefits from local sources of raw materials, especially cotton. Raw cotton has to go through a series of treatments before it can be used to make fabrics and garments.
One process is dyeing. Over one million tonnes of cotton are dyed each year in Brazil, with blue being the most popular colour.
The wastewater from textile dyeing is contaminated with various chemicals. These can have adverse effects on human health and the environment.
Due to the amount of pollution, primarily from sewage and industries, São Paulo’s Tiete River can no longer be used for any kind of human activity near the metropolitan areas.
Even after treatment at wastewater facilities, chemicals can end up in the effluent that is discharged into rivers and flows into other water bodies.
In Brazil efforts are underway to improve the situation. The National Service for Industrial Training (SENAI) is working closely with wastewater treatment facilities to research new methods for industrial effluent treatment.
One project, which is supported by the IAEA, is in cooperation with the National Nuclear Energy Research Institute (IPEN). IPEN scientists collect samples of textile dye wastewater for treatment at their institute’s electron beam irradiation facility.
Electron beam facilities, like this one at IPEN, are already used around the world to sterilize medical supplies, clear food from microbial contaminants and improve the quality of cables.
At the IPEN laboratories the wastewater is prepared for irradiation. An electron beam accelerator creates electron beams that irradiate the target object to bring about the desired changes. The aim of the research is to reduce colour and the toxic content in industrial effluent.
Irradiation with electron beams breaks down the chemicals into smaller fragments, which makes any subsequent conventional biodegradation treatment more efficient. It also means they pose less of a risk to the environment and human health when found in rivers or other water bodies. Irradiation does not make the water radioactive.
Once the samples have been removed from the accelerator, the scientists need to assess the results of the irradiation treatment.
The first tube shows untreated textile dye wastewater, the second irradiated water and the third irradiated water that has been treated with a higher dose. The results show that irradiation produces a much cleaner and safer effluent.
Toxicity evaluation tests are also conducted to see the impact of treated and untreated wastewater on aquatic life. In this test, the water fleas lived longer in the irradiated wastewater.
IPEN is working closely with industries to encourage them to implement this technology. The next phase of the project is to use a mobile e-beam irradiator, like this one in South Korea, at facilities to demonstrate how the technique works.
The IAEA is working with 13 countries to develop this technology further in an effort to make wastewater safer and reusable.
