Circular pigment innovation turns wastewater sludge into textile printing ink

A new collaboration in the United States is attempting to turn one of the world’s largest urban waste streams into a sustainable input for textile printing. Technology company Bioforcetech, textile developer RDD, and sustainable ink manufacturer Virus Inks are collaborating to commercialize a carbon-negative screen-printing ink derived from treated sewage sludge.

The initiative focuses on converting biosolids from wastewater treatment into a carbon-rich pigment. It can replace conventional fossil-based carbon black used in textile inks.

The waste problem creates a material opportunity

Sewage sludge remains a major global waste challenge. According to the United Nations Environment Programme, millions of tons of biosolids are generated annually by wastewater treatment plants worldwide. Much of this waste is either landfilled or used as agricultural fertilizer, both of which carry environmental risks.

In the United States alone, wastewater treatment facilities generate about 7 million dry tons of biosolids each year, according to the United States Environmental Protection Agency.

Handling this material is costly and environmentally sensitive. When disposed of in landfills, biosolids can produce methane, a greenhouse gas far more potent than carbon dioxide. The collaboration between Bioforcetech and its partners aims to convert this waste stream into a valuable industrial input.

From biosolids to carbon pigment

Bioforcetech developed a proprietary process that converts sewage sludge into a stable carbon material called OurCarbon.The process starts with microbial drying. Thermophilic bacteria generate heat naturally and reduce the moisture content of the biosolids. The dried material then undergoes pyrolysis, a high-temperature process in the absence of oxygen.

This process converts organic matter into a carbon-rich biochar. The resulting pigment can be used in inks, coatings, plastics, and textile printing.

According to Bioforcetech, converting biosolids through this process can reduce greenhouse gas emissions by up to 10 tons of CO₂-equivalent per ton of material processed, as the carbon becomes permanently locked in a stable form.

A carbon-heavy industry input

The innovation targets a major industrial material. Carbon black is one of the most widely used pigments in the world. It is used in textiles, plastics, tires, coatings, and printing inks.According to the International Carbon Black Association, the global carbon black market exceeds 14 million tons annually.

However, the conventional production process is highly carbon-intensive because it relies on heavy petroleum oils. According to the International Energy Agency, producing carbon black can generate around 2.5 to 3 tons of CO₂ emissions per ton of product, depending on the production technology.

Replacing even a small portion of this pigment with circular carbon materials could therefore reduce emissions across multiple industries.

Textile printing under sustainability pressure

Textile printing remains an important but often overlooked part of the apparel supply chain. According to the Smithers Market Research, the global textile printing market is expected to exceed $10 billion by 2027 as fashion brands increase product customization and graphic printing. Many of these prints still rely on fossil-based pigments and plastisol inks. As brands adopt climate targets and stricter environmental standards, chemical inputs used in printing are coming under scrutiny.

The new ink formulation developed by Virus Inks uses the OurCarbon pigment in a water-based system. The formulation is about 80 percent bio-based while maintaining the color depth and durability required for garment printing.

Implications for the apparel supply chain

The collaboration highlights how circular materials could expand beyond fibers and fabrics into the chemical inputs used across textile production.

Wastewater treatment plants could become future suppliers of feedstock for textile pigments. This would create a new circular value chain connecting urban waste management with garment manufacturing.

In the apparel sector, under increasing pressure to cut carbon emissions, such innovations could help reduce the environmental footprint of textile printing.

Industry experts note that scaling the technology will depend on infrastructure, cost competitiveness, and regulatory approval. However, the concept demonstrates that waste streams once considered environmental liabilities may become valuable resources for the future textile economy. If commercialized successfully, sewage sludge-derived pigments could represent a new frontier in circular textile chemistry.