Natural Dyes : Better for you, Better for the Planet

Over the last decade, multiple reports have suggested that the fashion industry is the most polluting industry in the world. Various estimates place the carbon and GHG emissions at anywhere between 2% and 10% of the world’s total carbon and GHG emissions. Whichever side of the spectrum the real figures be at, fact remains, the most polluting aspect of the industry is the dyeing process. And we, here, at Sodhani Biotech, are committed to changing that.
The problem with Conventional Dyes
Most synthetic dyes used in the fashion industries are manufactured using petrochemicals, and use heavy metals as mordants. These are not biodegradable, and leech toxic chemicals and heavy metals into our soil and water bodies. The average mill is likely to discharge approximately 1.5 million litres of effluents, every day. Because synthetic dyes are cracked from crude oil, there will always be carbon emissions. But even more terrifying is the disposal process. Each dye bath must be discarded, but there aren’t enough systems in place to regulate the safe disposal of toxic waste-water, which ends up in rivers.
Let’s look at the Noyyal River, for example. The Noyyal, which flows past Tirupur, one of India’s largest textile hubs, is polluted to a point that farmers who live downstream, within a radius of 5 km, have had to abandon farming. The floodgates of the Orathupalayam dam, located downstream on the river, remained closed for many years, due to fear of the pollution the water may cause. And that fear wasn’t ill-founded. When the dam was indeed opened, in 2005, the Cauvery, of which the Noyyal is a tributary, ended up with 0.5 million cubic feet of toxic effluents, over 400 tonnes of dead fish and toxic sludge in the riverbed, many metres thick!
Now, imagine wearing all of that, through your clothes! Chemical dyes have been identified as endocrine disruptors, which is to say they disrupt the flow of hormones in the body. They are also carcinogenic (cancer-causing) and can severely damage the mucous membranes of the organs. All of these conditions have been found amongst textile workers. To make matters worse, every time clothes are washed, a small amount of dye is released into the earth’s waterways. Though, of course, this has less to do with the individual than with the textile and garment manufacturers.
The Solution
Natural dyes are better not just for the environment and the human body, but have even been found to be more economically viable, especially in the case of India, which has a tradition of natural dyeing. The only caveat is, the textile industry needs to turn to natural dyes, over cheaper, synthetic dyes. According to a report by Arizton Advisory and Intelligence, the global natural dye market is anticipated to generate revenues of approximately $5 billion by 2024, growing at a CAGR of around 11% from 2018 to 2024.
Natural dyes lend anti-microbial and higher UV absorption properties to the fabrics they are used on, giving them better protection from the sun’s harmful rays. Natural dyes are also substantive. They may or may not need a mordant to fix to the fabric. In fact, a fantastic number of natural dye sources contain tannins, which are binding agents and don’t need a separate mordant. The most common mordant used in natural dyes is alum, which is also used in food and body products. Think Dirty rated alum a 4/10 in toxicity, putting it in the green or ‘safe’ category for long term skin exposure. Alum is what we use, at Sodhani Biotech, and we only use it for water purifying. Other effective and safe mordants are copper and iron. Not only are these metals generally safe, but they are also required in very small quantities to meet the purpose.
We, at Sodhani Biotech, are manufacturing natural dyes from plant-based sources, nearly all of them waste materials, ensuring circularity and biodegradability. We do not harvest any of our dye sources from fresh natural resources. With zero chemicals and no waste water generated in the manufacturing, our natural dyes are a far better and more responsible choice, especially in comparison to synthetic dyes.
Take these figures, for example. After natural dyeing, the waste water COD (Chemical Oxygen Demand) is approximately 800-1,000 mg/l, and after synthetic dyeing, the waste water COD is approximately 3,500-5,000 mg/l. What that means is, natural dyes reduce the ETP (Effluent Treatment Plant) load as well as the cost of water recycling. Higher COD in water translates to greater level of oxidizable organic matter and, consequently, a lower amount of DO (Dissolved Oxygen) in the water. This DO depletion, due to organic contamination, is fatal to marine life. The waste water TDS (Total Dissolved Solid), after natural dyeing, is anywhere between 400-500 PPM, whereas that after synthetic dyeing is upwards of 2,000 PPM—anywhere between four and five times the environmental impact of natural dyes. All in all, the carbon footprint of natural dyes is 25% lower than disperse dyes and 60% lower than reactive dyes during the manufacturing process.
What the Future holds
With sustainability becoming a major concern worldwide, organisations in industries like textiles are looking for ways to mitigate the impact of their operations on the environment by opting for sustainable and biodegradable dyes. As a result, the demand for naturally sourced dyes and pigments is expected to surge considerably. Many retailers are also exploring the use of colouring techniques in an effort to decrease their ecological impact, wherein a single dye is applicable for all textile fibres.
One of the main researches and innovations in natural dyes is the use of enzymes and ultrasonic dyeing techniques, aimed at avoiding the use of metal mordants and obtaining comparable or better results than synthetic dyes, something we, at Sodhani Biotech, are delving further on, with one of our research projects being incubated at the University of Delhi.
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