Laundered cotton microfibres break down faster than cellulosic microfibres from toilet tissue in wastewater treatment, fresh water, and saltwater environments, new research has found.
- Moreover, microfibres from synthetic materials do not readily biodegrade and are persistent after the testing periods in all environments tested.
- The researchers from North Carolina State University and Cotton Incorporated showed that cellulosic microfibres from flushable wipes, tissue paper, and cotton fibres generated from bleached cotton jersey knit fabric biodegrade extensively across all tested conditions.
- The study also found that the presence of polypropylene in blended nonwoven wipes did not hinder the biodegradation of the cellulose component. This suggests that even when combined in a single product, the cellulosic component can still degrade independently, while the polypropylene remains undegraded.
THE PROBLEM: Since toilet tissue microfibres enter the wastewater treatment system at a rate of 45 pounds per year per person in the United States, they are one of the most significant contributors to cellulosic microfibres.
- The annual microfibre emissions from toilet paper use in the United States equals the microfibre shedding from washing 1.4 million T-shirts.
- The calculation is based on these assumptions: (1) Tissue paper is composed entirely of microfibres. (2) The average weight of a cotton t-shirt is 215 grams. (3) The average toilet paper consumption in the US is 20,500 g/person/year. 4. On average, each t-shirt wash releases 0.014 g of microfibres per t-shirt.
THE METHODOLOGY: This research studied the biodegradation of cotton microfibres, commercially available flushable wipes, polypropylene-based nonwoven wipes with a cellulose component, and toilet tissue. The biodegradation was tested in wastewater treatment plant solids, seawater, and lake water using standard methods in an ECHO respirometer.
- The experiments continued until carbon dioxide (CO2) emissions plateaued, and the final extent of biodegradation was calculated based on the theoretical CO2 production derived from elemental analysis.
WHAT THEY SAID:
Our research confirms cotton microfibres biodegrade equal to or faster than toilet tissue microfibres in wastewater treatment, fresh water and saltwater environments, demonstrating society’s and nature’s ability to manage them.
— Jesse Daystar
Vice-President and Chief Sustainability Officer
Cotton Incorporated
These results reaffirm that fibres found in these cellulosic and cotton-based products can biodegrade easily in various environments. Our research highlights the importance of choosing natural fibres over synthetic alternatives to reduce the accumulation of non-biodegradable waste in our environment in order to promote a more sustainable future.
—Mary Ankeny
Vice-President (Product Development and Implementation Operations)
Cotton Incorporated
