Climbing the PPE plastic mountain

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ven when you’re alone and outdoors, evidence of the Covid-19 pandemic can be found in hedgerows, beside gutters and spilling out of public waste bins. Abandoned single-use plastic masks and gloves are an eyesore, as well as a sinister reminder of how our lives have changed beyond recognition in the last year.

But items dropped by careless members of the public are a drop in the ocean compared to the mountain of personal protective equipment (PPE) used to protect healthcare professionals risking their lives on the frontline.

Medical-grade masks are made from a dense thermoplastic called polypropylene, which doesn’t biodegrade and can’t be recycled. Researchers estimate that it takes around 500 years for solid polypropylene to be fully broken down by the environment.

Respirators, face shields, goggles, gloves and gowns are all made of similarly hardy plastics. All these items are usually designed for just one use before being tossed in the incinerator. The UK’s National Health Service (NHS) already spent £700m a year disposing of medical waste in this way before the pandemic.

PPE use has understandably soared since SARS-CoV-2 arrived to wreak havoc on the world. UK Government figures show 8.4 billion PPE items were distributed to health and social care services in England between February 2020 and February 2021.

Although PPE is vital, particularly in pandemic situations, the extra plastic required for Covid-19 is a concern for the NHS, which only recently launched a national drive towards sustainability to cut carbon emissions.

As part of its Plastics Pledge, all providers, retailers and suppliers to the NHS had to commit to no longer purchasing single-use plastic items such as stirrers and straws by April 2020.

Some hospitals, including the Royal Cornwall Hospital Trust (RCHT), are getting creative to solve the plastic PPE problem. RCHT is recycling its disposable masks into a material that can be used to make bottles, bins and toolboxes after partnering with recycling machinery manufacturer Thermal Compaction Group (TCG).

The Cardiff-based firm’s technology, called Sterimelt, heats polypropylene to up to 350^oC. It is then compressed into rectangular blocks that can be sold on and converted into new plastic products.

It also means that the volume of waste that needs to be transported off-site is reduced. TCG claims that for every 10,000 kg of waste produced through its Sterimelt technology, hospital trusts will prevent 7,500 kg of carbon dioxide emissions.

“We hope this will be a real game-changer in the way we tackle single-use PPE, not only for us here in Cornwall but across the UK and beyond,” said RCHT general manager Roz Davies in a press release.

“The use of masks has grown extraordinarily this year but now we have the option to recycle them, as well as other items such as theatre wraps and gowns that would previously have been transported out of Cornwall for specialist incineration.”

At Swansea University, researchers have also been exploring how to turn Covid-related plastic into something useful. Chemist Moritz Kuehnel has a long-standing interest in renewable energy with a particular focus on hydrogen fuel. During the pandemic, he couldn’t help but notice the discarded plastic PPE.

“You walk down the street and see face masks and gloves,” he says. “All this disposable plastic waste is everywhere, and it’s just been skyrocketing throughout the pandemic.”

Kuehnel’s team is developing a process called photoreforming, which uses sunlight to not only convert the non-recyclable waste into hydrogen fuel but kill off viruses at the same time.

The process involves a photocatalyst (a material that absorbs light and can convert it into energy) to break down the plastic waste and turn it into hydrogen. This chemical reaction also generates reactive oxygen species to kill bacteria and viruses.

“The beauty of the process is it’s very simple. You don’t need a fancy reactor or high-cost apparatus,” says Kuehnel. “You take your medical waste, put it into the water, add the catalyst and then you shine a light on it.”

This action produces hydrogen from the water and breaks down the plastic. “Applying our technology to reprocess just 1% of medical waste would save millions and mitigate pollution at the same time,” he adds.

Kuehnel says the project is still in its early stages. But it’s already garnered attention from the Welsh Government, which has awarded £47,000 towards the research. The team is now actively looking for industry partners to commercialise the technology.

In addition to finding a better way to break down medical waste, other researchers are investigating whether more items of PPE can be safely re-used. Researchers at the University of Nebraska Medical Center are investigating whether ultraviolet light can decontaminate masks and respirators, so they pose no risk if they’re donned for a second time.

In Columbus, Ohio, manufacturer Battelle claims, its Critical Care Decontamination System - housed in a shipping container - can decontaminate up to 80,000 items of PPE at a time.

While the main priority right now is getting the public health crisis under control, governments and healthcare systems must not underestimate the environmental consequences of the pandemic. Hospitals need more options for tackling PPE waste to ensure, Covid-19 doesn’t threaten our planet in the same way that it has threatened our lives.