In addition to lowering treatment costs in biobased dyes, there is a significant reduction in the consumption of conventional energy required to power the Effluent Treatment Plant (ETP).

Tiruppur looks to sustainable dyeing solutions to revive its rivers

As the environmental and health hazards of synthetic dyes continue to grow, entrepreneurs are working towards transforming the textile industry with biobased dyes, despite challenges like the secrecy of the dyeing process and higher cost

“When dyeing industries in Tiruppur left the effluent water directly into the river streams,” said Priyadarshini Subramaniam, a resident of Tiruppur, “I had several times witnessed the impact of the untreated discharge. If the dyers use green dyes in their industry and let it out untreated, the wells and bores in our farms would also turn green, affecting our food, agriculture, drinking water, cattle, etc.”

“We are a very eco-conscious family and want our children to grow in a healthy environment. We soon understood that it is possible only with a green reformation in each business sector to battle the ongoing climate crisis,” added Priyadarshini, who grew up near the dying Noyyal River and always wanted to bring it back.

With her family’s three decades of experience in the textile industry to back her, Priyadarshini ventured into the realm of biobased dyeing. 

While trying to establish her business, Priyadarshini realised there was no business formula that she could follow because the biodyeing process was shrouded in secrecy. “There are lots of bio-dyeing companies in Tiruppur. But nobody will help you learn the ingredients or processing. They are kept secret. I understand that they have spent several years trying to figure out the dyeing recipe. Unfortunately, the secrecy prevents this from becoming a prevalent business model.”

Handloom weavers who make natural dyed handlooms. Photo: Gowthami Subramaniam

Synthetic dyes provide easy access, advanced technology

Accessibility is one of the prime reasons for the popularity of synthetic dyes.  According to T. Kumar, a natural dyeing expert from Tiruppur, “While synthetic chemicals are easily accessible in the market, biobased dyes have yet to gain traction.” Biobased dyeing also is a longer process. Priyadarshini, who was trained in biodyeing by Kumar, said, “I solely use herbal powders and solutions to pretreat the fabric, which takes longer than using synthetic chemicals to wet the fabric or garments.”

Prabhu, a sustainable textile technologist in Coimbatore, challenged the popular belief that dyeing chemicals are the sole cause of pollution, stating that a fabric undergoes multiple stages of pretreatment with synthetic chemicals to make it dye-ready. “Although soaking fabric in water for days is essential before dyeing, the use of synthetic textile chemicals has significantly reduced the soaking time to a few minutes. 

Furthermore, synthetic chemicals are used to remove vegetable matter and dirt from the fabric, ensuring that the dyes adhere uniformly,” he said.

“To enhance the colour yielding of dyes, water is mixed with chelating agents during treatment to remove heavy metals from water, which reduces the processing cycle. Additionally, synthetic chemicals like peroxide are used to bleach the fabric to ensure uniformity of dye colours,” Prabhu added. 

Shade matching is another challenge with biobased dyes. “The fabric’s colour may vary slightly after dyeing because of the distinctiveness of the natural raw materials that depend on factors such as the season, rainfall, geographical location, etc,” Prabhu said. 

But there is a solution to this problem. S. Periyasamy, chief executive officer of AIC-NIFTTEA Incubation Centre for Textile and Apparel, said, “We have created a special facility in our institute to extract dyes in powder form as the shade problem arises usually in liquor form. But unlike synthetic dyed garments that retain colours for a longer time, biobased dyes will fade out with washing, rubbing, and sunlight exposure.”

Prabhu further explained that to eliminate the harmful chemicals retained in the synthetic dyed fabric, “A neutralising chemical is applied before dyeing, and then finishing chemicals are used to enhance the texture of the fabric.”

The high costs of biobased dyeing has also led to a low demand in the market. “The quantity of dyes required for biobased dyeing is 10 times higher than fossil chemicals, leading to a retail price that is 3 to 4 times higher. This has resulted in low demand in the domestic market, but there is a high demand in the export market. Foreign buyers visit our companies and place orders because there is greater awareness of sustainability among their customers,” Priyadarshini said. 

The undeniable dependence of chemical dyes on fossil fuels 

“The synthetic chemicals used in pretreatment to finishing, are all derived from hydrocarbons of the petrochemical industry, making the chemical textile practices heavily reliant on the fossil fuel industry,” Prabhu said.

Raj Tanna, founder and managing director Schutzen, which develops biobased and biodegradable chemistries for the textile industry, stated, “This industry consumes one-fourth of the world’s chemicals, with around 8,000 chemicals being utilised, mostly from fossil fuels such as coal tar and petroleum, leading to problems such as pollution, non-biodegradability, and climate change. It is important to recognise the freshwater pollution due to fossil chemicals and switch to renewable alternatives.”

How biobased dyes ensure sustainability 

Lesser chemicals in water bodies

“Tiruppur primarily employs synthetic reactive dyes that demand more auxiliaries and supporting agents to get them into the fabric, leading to higher levels of sulphate content and salt in the Effluent Treatment Plant (ETP),” said Dr. Prince Kumar, DGM of Manohar Filaments in Delhi & Board of Directors, FSLCI (Forum for Sustainability through Life Cycle Innovation e.V.).

“Shifting to a biobased dyeing and chemical processing would significantly reduce the levels of COD [chemical oxygen demand] and BOD [biochemical oxygen demand] in the ETP load,” stated Yogesh Gaikwad, director of the Society of Dyers and Colourists. “At present, the ETP load is very high.”

Priyadarshini said, “Unlike the harmful textile sludge from ETP ending up in the landfill that does not biodegrade, the sludge from the biobased chemicals is harmless and can be used as a raw material for agarbatti industries.”

“Regarding biobased textile chemicals, a complex ETP is not necessary. A simple wastewater treatment plant is sufficient,” said Prince. “During my trials with biobased chemicals, I observed a reduction of about 45% in ETP load.”

However, Priyadarshini said, “There is currently no established standard or protocol for the treatment of biobased effluent. Typically, small quantities of effluent are treated using basic water treatment methods. However, we are compelled to treat the effluent at conventional effluent treatment plants out of fear that our factory may be sealed by officials. In the absence of standards, officials expect us to follow existing protocols, even if they are not relevant. It is crucial for the government to develop a dedicated protocol for bio-effluents.”

Reduction in energy consumption

Priyadarshini highlighted that in addition to lowering treatment costs, there is a significant reduction in the consumption of conventional energy required to power the ETP.

According to Tanna, “Wet processing in textile with fossil chemicals alone accounts for 38% of the thermal energy requirement.” Prabhu added, “The smooth finishing of garments heavily relies on steam, which is mostly generated from thermal energy.”

“I have seen a reduction in water consumption and steam requirements with the use of biobased textile chemicals. For 1 kg of fabric manufactured with synthetic dyes, you need 42 litres of water to rinse off the chemical residues and at least 10 kg of steam. This can be reduced to roughly half with biobased textile chemicals,” said Prince.

The senior manager of a Tiruppur-based textile industry, producing 30 tonnes of fabric per day, anonymously revealed, “We use around 40 litres of water for every kilogram of fabric produced, consuming 0.75 units of electricity for every 40 litres. One litre of water produces 25 grams of toxic sludge. The cost of steaming per kilogram of fabric is around ₹1.5-2. ETP alone accounts for roughly 30% of the total electricity consumption.”

Gaikwad stated, “In the case of biobased chemicals, most of the raw materials are produced in India. We could potentially reduce the need for crude oil, giving us a forex advantage. Additionally, the bio textile sludge can also be burnt to produce energy in place of thermal energy.”

The need for mindful selection of raw materials 

“Looking at the chemicals involved is crucial to determine if a garment made of cotton, a natural product, is fit for landfill as it may lose its biodegradability after several treatments with fossil chemicals,” said Periyasamy.

Gaikwad pointed out, “Even if we transition to 100% biobased materials, some chemicals may still be used. It’s crucial to recognise that not all biobased substances are biodegradable. Therefore, understanding the distinction is critical.”

“Choosing raw materials from multiple sources is important to avoid the impact of biodiversity loss,” said Tanna, highlighting the example of deforestation of the Amazon forest to make way for palm trees. “Our technology is based on seeds and biowaste, not crops. For instance, we use tamarind seeds to produce biochemicals by breaking the outer shell and using the sperm through patented reactions to create dyes,” he added.

Tanna stated, “Our technology reduces COD levels to between 150-180mg/g and BOD levels to roughly 78mg/g, whereas fossil chemicals have levels above 2,500mg/g and 500mg/g, respectively. However, our technologies are only available at the pretreatment stage. If companies choose to use fossil dyes, then again the COD and BOD values will increase. The use of biobased technologies at least in one process chain could help companies achieve carbon neutrality.”

Other alternatives

According to Gaikwad, there has been a shift towards pigment-based dyeing technology, which requires very little water compared to reactive dyes that use 100 gms of salt per litre of water, making it difficult to remove during effluent treatment. Tanna, however, argued that pigments are also petrochemical-based and that there are only a few natural dyes and bacterial pigments available in the market, most of which are still in the development stage.

Prabhu highlighted that Tiruppur was a pioneer in adopting the Zero Liquid Discharge concept and local companies formed a cluster to share a common Effluent Treatment Plant (ETP). “There are eight common ETPs in Tirupur, and the companies have already embraced this system, so they are accustomed to doing things faster and quicker,” he added. However, he acknowledged that bio-dyeing requires significant investment in research and development, resulting in a halt to ongoing production with a time commitment to lots of trials and errors. Whereas, the use of fossil chemicals is readily available in the market.”

Gaikwad, however, argued that most biobased solutions do not require changes in machinery, procedures, etc. “At least some of the procedures need to be changed. There is very little argument for people not to go into biobased,” he said.

According to Tanna, “The current textile dyeing industry heavily depends on toxic fossil and mineral oil from the petrochemical sector. In contrast, our technology is plant-based and emits non-toxic biocarbon that are absorbed by living organisms.”

Prince tested Tanna’s technology and found it promising, but faced challenges in adopting it, stating, “Although the technology shows great promise and cost-effectiveness, we require a complete range of chemicals for bioprocessing and dyeing, some of which are not yet supplied by Schutzen.”

Prince commented on the traditional way of doing business in India, stating that “people only check direct costing and not indirect costing. The textile business owners have to be more concerned about the quality than quantity. We are not very aware of the Environmental Impact Assessment, and that’s exactly what we are losing.”

The senior manager at one of the largest textile industries in Tiruppur further added, “We tried natural dyes, but it was difficult to achieve colour consistency and fastness. So we only use natural dyes for customers who specifically ask for it. Biodyeing is currently a more expensive technology, even though it can reduce carbon footprint and waste disposal. Therefore, customer awareness is key to such a business.”

While working as an R&D consultant at Natural Dye House in Tiruppur, Prabhu emphasised the importance of the natural feel of garments to customers. He stated, “It’s also essential to note that biobased dyes are sensitive to detergents, which are also derived from petrochemicals. So, our entire lifestyle needs to change to achieve successful sustainable technology.”

Dr Madhuri Nigam, head of the department of Fabric & Apparel Science at Lady Irwin College (University of Delhi), stated, “Many of our solutions fail at the ground level and policy level. The government needs to make sincere and honest efforts, providing real-time intervention to teach industries the right ways to do things. It requires a collective effort from customers, workers, industries, and governments to achieve our 2030 UNSDG and 2070 net-zero target goals.”

Ambiguity in certification standards a challenge for manufacturers

Tanna’s product is certified 100% biobased by USDA, indicating that the chemicals contain no fossil carbon. However, Priyadarshini noted, “Even if a product is GOTS certified(widely known organic certification), there may still be permissible levels of harmless chemicals. Biodyeing, as a completely natural process, requires a unique label. The current certifications for dyeing are not adequate. We conduct tests as per buyer’s requests and urge governments and organisations to take steps to address this issue.”

The way forward

Prince explained that the Philippines has implemented certain arrangements such as zero liquid discharge requirement and no toxic chemicals in the textile industry. Regarding India, he said, “69% of the people are just earning below ₹500 per day. We cannot expect them to afford this. As a business, we need to segregate the market at this moment. We should focus on selling biobased textiles to high-end consumers and export markets like Europe where people are aware and can afford it.”

Periyasamy suggested focusing on European markets first. He pointed out that in France, a climate tag has been introduced, which carries details of the resources used, much like a price tag. He further recommended, “Biobased garments could also be applied to kids’ garments where the buyers frequently change and do not expect colour fastness.”

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