Cotton Textile Waste composted in groundbreaking Goondiwindi trial

A 12-month trial on a cotton farm just outside the rural town of Goondiwindi, Queensland in Australia has shown it’s possible to divert large amounts of cotton textile waste at end-of-life from landfill with no harm done to soil health or cotton yields.

Project collaborators are confident that with a solid business plan and more research, returning shredded cotton products to cotton fields could soon offer soil health benefits and a scalable solution to the massive global problem of textile waste.

“At the very least, the trial showed that no harm was done to soil health, with microbial activity slightly increased and at least 2,070kg of Carbon Dioxide equivalents (CO2 e) mitigated through the breakdown of these garments in soil rather than landfill,” said Dr Oliver Knox, a cotton industry-supported soil scientist.

“The trial diverted around two tonnes of textile waste from landfill with no negative impact on cotton planting, emergence, growth or harvest.  Soil carbon levels remained stable and the soil’s bugs responded well to the added cotton material,” continued Dr Knox.

“There also appeared to be no adverse effect from dyes and finishes although more testing is needed on a wider range of chemicals to be absolutely sure of that,” Dr Knox said.

According to farmer Sam Coulton the cotton fields easily “swallowed up” the shredded cotton material, giving him confidence that this composting method has practical long term potential.

“We spread the cotton textile waste a few months before cotton planting in June 2021 and by January and the middle of the season the cotton waste had all but disappeared, even at the rate of 50 tonnes to the hectare,” Sam said.

“I wouldn’t expect to see improvements in soil health or yield for at least five years as the benefits need time to accumulate, but I was very encouraged that there was no detrimental impact on our soils.

“In the past we’ve spread cotton gin trash on other parts of the farm and have seen dramatic improvements in the moisture holding capacity on these fields so would expect the same using shredded cotton waste,” he said.

The project, under the guidance of circular economy specialists Coreo, was a partnership between the Queensland Government, Goondiwindi Cotton, Sheridan, Cotton Australia, Worn Up and Cotton Research and Development Corporation, supported soil scientist Dr Oliver Knox of UNE.

Around two tonnes of end-of-life cotton textiles from Sheridan and State Emergency Service coveralls were processed at Worn Up in Sydney, transported to “Alcheringa” farm, and spread onto a cotton field by local farmer, Sam Coulton.

Coulton commented, “We’re encouraged by the initial findings and results of the project and look forward to expanding the trial over the next 12 months.  In this day and age, we should be part of the solution for taking cotton right back through the system. We grow it here, and we should be able to bury it here with positive environmental and economic impact on the local community.” 

According to Cotton Australia’s Brooke Summers there is keen interest in further collaboration from industry groups, government, farmers, brands and potential investors, saying “These results show us that it’s possible to find a scalable solution to cotton textile waste right here in Australia by returning these products to our farmlands.  We know there’s more research to be done and there are a lot of challenges still to overcome but the fact that it’s possible is what’s so exciting.”

“There’s certainly a huge amount of interest in this idea and the trial results, and while we don’t want to get ahead of ourselves, we are hopeful that over time this will evolve to deliver a scalable solution for cotton textile waste here in Australia,” Summers said.

“We’re excited to announce the trial will be replicated in the 2022-23 cotton season, with cotton farmer Scott Morgan’s Gunnedah property in NSW added as a second site.  This will give us further confidence the results we’ve already seen can be replicated across time and geographies,” Concluded Summers.

The project team will now set its sights on how best to collaborate on the way forward, options include further investigating the effect of dyes and finishes, finding ways to “pelletise” the waste so it can be spread on the fields using machinery, and a repeat trial with farmer Sam Coulton, who is also exploring ways to provide employment in the regional cotton community through this initiative.