Scientists turn facemasks into water and vinegar

Associate Professor Saeid Baroutian, University of Auckland. Image: Elise Manahan

Turning non-recyclable personal protective equipment (PPE) like facemasks into water and vinegar is a potential game changing solution to the growing problem of PPE polluting oceans and rivers.

The increasing use of PPE during the global pandemic poses many environmental risks to our rivers and seas, including through microplastic and chemical pollution as well the potential threat of entanglement or ingestion for marine life. For example, the amount of face masks that entered the ocean in 2020 was estimated at 1.56 billion according to Hong Kong based marine conservation organisation OceansAsia.

Now an amazing new process has been developed at the University of Auckland’s faculty of engineering to tackle this issue.

Shredded masks, gowns, gloves and plastic safety glasses go into a machine then hot, pressurised water and compressed air are applied. After an hour, all that is left is water and acetic acid (vinegar), plus oxygen and small amounts of carbon dioxide.

The PPE-to-liquid process is carried out at a temperature of 300°C and takes about an hour in a small prototype machine in the University's laboratory.

"We are closing the loop on this ever-growing serious waste issue and providing a circular solution that truly is clean and green."

Professor Saeid Baroutian, University of Auckland

"This is a clean, chemical-free solution which will be a game changer internationally," said Dr Saied Baroutian, an associate professor in the faculty's department of chemical and materials engineering.

"The technology destroys the waste completely. The liquid produced in the process is safe, inert and can be reused—the vinegar or acetic acid can be used for disinfecting and the water can be reused for the processing cycle therefore minimising water consumption and helping with sustainability."

The research teams are now taking steps to develop the solutions into a larger scale pilot system and, learning from that, will develop a full-scale proof-of-concept.

The process has been developed at the university in collaboration with the Faculty of Medical and Health Sciences and the Universities of Otago and Waterloo, Canada.

In terms of cost, the researchers have already completed an analysis which shows a large-scale version of their system could process PPE waste at a cost comparable to the current practice of sterilisation and landfilling. "And in terms of the environment," added Saeid, "the savings on offer are huge."