Greener recycling for PPE waste

Cornell University engineers have come up with a solution to sustainably recycle used surgical masks, plastic face shields, and medical gloves and gowns.

Healthcare facilities around the world are creating about 7.5 pounds (3.4 kg) per person of personal protective equipment (PPE) waste daily through COVID-19-associated services, according to the United Nations Environment Programme. This means one hospital with 300 medical personnel could generate more than a ton of medical garb waste daily. That translates to more than 400 tons of annual medical PPE waste in a single COVID-handling facility, said Fengqi You, professor in energy systems engineering at Cornell University.

You and his doctoral student Xiang Zhao have developed a solution that could help reduce the plasticised medical-protection garb back into its original form — such as chemicals and petroleum — and then recycle it, perhaps into fuels. The method — a medium-temperature reaction called pyrolysis — is said to involve no incineration or landfill use.

The engineers propose collecting PPE waste from hospitals and medical centres, then sending it to pre-processing and decontamination facilities. There, it would be shredded, sterilised and dehydrated to transform it into small particles, then brought to an integrated pyrolysis plant.

In the engineers’ model, the medium-temperature pyrolysis (about 1200° F) can deconstruct the plasticised gowns and gloves, which are derived from petroleum, into chemicals such as ethylene, butane, gasoline, bauxite, propene, propane, diesel, light naphtha and sulfur.

In the paper’s energy analysis and environmental lifecycle assessment, the proposed optimal PPE processing system avoids 41.52% of total landfilling and 47.64% of the incineration processes. This method shows an environmental advantage by reducing total greenhouse gas emissions by 35.42% emissions from conventional incineration and energy saving by 43.5% from landfilling, the researchers said.

“This is a viable strategy for disposing of and processing waste PPE,” You said. “It is a treatment method with low greenhouse gas emissions, it alleviates fossil fuel emission depletion and it saves a lot of polluting material from landfills.”

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