Advance Denim’s aggressive investment in sustainable production is paying off. In 2021, the denim manufacturer released its most eco-friendly dyeing process yet after three years of constant experimentation and innovation.
BioBlue Indigo is designed to reduce the harmful chemicals that pollute wastewater after the denim dyeing process.
But how does it work? BioBlue’s indigo dyeing process changes the indigo dyes from powder to liquid form without using sodium hydrosulfite, an unstable, flammable chemical that can be difficult to transport. Sodium hydrosulfite forms a high concentration of salts in the denim manufacturing process, and they are hard to remove from wastewater and damaging to the environment. Using this chemical, sulfates can build up in the wastewater, and at high enough levels, release harmful gases that could cause further environmental damage.
BioBlue Indigo is the latest of Advance Denim’s sustainability success stories. Since 2018, the denim manufacturer has reduced energy consumption per yard of fabric by 42 percent and cut water consumption 58 percent. The company also increased its Higg carbon footprint verification score from 49 to 81 in just a two-year span.
While these are major accomplishments, Advance Denim prides itself the most on launching Big Box dyeing in 2020. Big Box dyeing saves up to 98 percent of water during indigo dyeing, without sacrificing the consistency of traditional rope-dyed indigo denim. In an industry that needs sustainability, Big Box dyeing lets denim maintain its traditional wash and color consistency, while saving significant amounts of water. And less water means less effluent.
But Amy Wang, the general manager of Advance Denim, wanted to go a step further. She sought to use less water, energy and chemicals during dyeing, and also clean up the chemicals that were currently used to dye indigo.
Additionally, since Advance Denim was investing in eco-friendly materials such as recycled fibers, Tencel and organic cotton, the company realized it didn’t make sense to bathe those fibers in toxic chemicals during the indigo dye process. BioBlue Denim is a cleaner way to reduce indigo and prevent sustainable fibers from being dyed with hazardous chemicals.
BioBlue: Less salt, fewer chemicals
To validate its in-house findings on BioBlue Indigo, Advance Denim turned to Amanda Cattermole of chemical management consultancy Cattermole Consulting Inc. to research the process. Cattermole, an expert in both sustainability and textile chemical management with more than 30 years of experience in denim innovation and textiles, confirmed that BioBlue was a more environmentally friendly way of reducing indigo without using sodium hydrosulfite.
“It is no secret that sodium hydrosulfite is environmentally unfavorable because it produces hazardous effluent that must be treated prior to discharge,” Cattermole said. “Some of the compounds, including salts, coupled with the high PH required in dyeing, contaminate the environment if the effluent is not treated.”
Upon reviewing the data, she concluded that the effluent produced from the BioBlue process contains less salt and results in a considerably lower chemical oxygen demand (COD) and biochemical oxygen demand (BOD) than the incumbent process that used sodium hydrosulfite. COD measures the total of chemicals in wastewater, while BOD calculates the oxygen levels needed for bacteria to break down organic chemicals in the water.
The BioBlue process reduced COD levels 71 percent in the dye bath and 34 percent in the first wash bath compared to the incumbent process. BOD levels were cut 60 percent in the dye bath and 46 percent in the first wash, respectively. The lower the totals, the more efficient the process is at removing potentially harmful chemicals.
As with Advance Denim’s prior innovations, the company said it was crucial that the resulting denim had the same deep, dark indigo shades that have gained traction among brands. However, the yarns also retain bright, white cores that can make BioBlue Indigo easier to laser, demonstrating that it is compatible with current sustainable wash methods.
BioBlue Indigo will be available from the Advance Denim mills in both Shunde, China and Nah Trang, Vietnam. With BioBlue Indigo, Advance Denim hopes to continue innovating with the goal of “creating the world’s most beautiful denim in the most sustainable way possible.”
Learn more about Advance Denim Limited here.