Disinfecting PPE for reuse and recycling

In response to a global shortage of PPE early in the COVID-19 pandemic, Dr Yvonne Anderson from The University of Auckland started researching a method for disinfecting PPE for potential reuse or safe recycling.

Together with Dr José Derraik, Dr Anderson pulled together a team from the Universities of Auckland, Otago, Canterbury and Waterloo, as well as New Zealand’s AgResearch, to collaborate on the research. The project also received $1.3 million in funding from New Zealand’s Ministry of Business, Innovation and Employment (MBIE) through the COVID-19 Innovation Acceleration Fund, plus a $46,000 grant from the Medical Assurance Society Foundation.

“Safety of healthcare workers during the current pandemic is critical to reducing community transmission of COVID-19, and this requires readily available PPE,” Dr Anderson said.

“The primary focus of our project was protecting healthcare workers and other frontline staff against the SARS-CoV-2 virus (the causative agent of COVID-19). However, it’s paramount that we also find ways to mitigate the ever-growing amount of medical waste that goes to landfills — or worse, that ends up polluting our lands, rivers, and seas — magnifying the global problem of plastic pollution.”

In a high-security laboratory, University of Otago researchers led by Professor Miguel Quiñones-Mateu performed tests on the efficacy of heat and UV methods for disinfecting clinical PPE against SARS-CoV-2. Their results, published in the journal Pathogens, showed that UV disinfection was not reliable on the irregular surfaces of PPE, but dry heat was effective. The researchers also found replication-competent virus remained on face masks for up to five weeks at room temperature.

The most recent stage of the project has been to build and test a prototype mobile disinfection unit in a shipping container at Port Taranaki. Port Taranaki Head of Commercial Ross Dingle noted, “As a border-facing operation, Port Taranaki has been at the front line during COVID-19, which has involved many of our people wearing PPE each day.

“It’s fantastic that this work has the potential to reduce the impact of PPE on the environment and ensure an ongoing safe supply of PPE, even in the event of supply shortages.”

Associate Professor Mark Staiger and his team at the University of Canterbury are now testing the effects of the heat treatment on PPE materials, to assess if disinfection compromises the required levels of protection in any way. Meanwhile, the next step for the prototype disinfection unit is to demobilise and transfer it to the University of Auckland Faculty of Engineering.

“That will then be with the team that are going to work on waste valorisation, so that we can actually make sure that we’re reducing our environmental footprint in health,” Dr Anderson said.

The aim is for unusable PPE waste to be broken down into water and largely harmless chemicals using hydrothermal processes. This work is being conducted by Associate Professor Saeid Baroutian at the University of Auckland’s Faculty of Engineering, with input from Professor Bill Anderson (University of Waterloo) and Dr Trudy Sullivan (University of Otago).

“We aim to close the loop on single-use PPE by completely deconstructing and converting unusable PPE waste into safe, inert and potentially valuable products,” Associate Professor Baroutian said. “The combination of disinfection and hydrothermal valorisation is a circular solution.”

Image credit: ©stock.adobe.com/au/Kat Ka

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