Australian hospitals incinerate thousands of tonnes of potentially infectious medical waste every year — and COVID-19 has supercharged the problem. A new partnership is looking for a better solution.
Every week, the average patient at home on peritoneal dialysis receives seven large boxes of dialysis pouches, each containing four dual-layered filter bags.
By the end of the week, all 28 bags will be in the bin.
It’s so much waste, said systems engineer Ryan Pike, that one Canberra dialysis centre was recently contacted by a patient’s neighbour who was sick of dialysis rubbish overflowing into their bin.
“It’s an astonishing amount that just gets thrown out,” he said. “The patients … they feel like it’s within their sphere of responsibility to not just throw this stuff away.”
Pike, the Chief Technology Officer for 180 Waste Group, is working with Newster Systems, Baxter Healthcare and a team of Australian National University (ANU) engineering students on a project to recycle this waste.
They’re processing the bags using an Italian technology known as frictional heat treatment.
Pike said it’s the first time the technology has been used to process clinical waste in Australia.
It’s also the first time it’s been applied to waste from peritoneal dialysis, a technique that uses a patient’s abdomen as a membrane.
Pike said 5000 t of peritoneal dialysis waste is produced each year in Australia.
“Essentially our solution is, instead of the waste going into the yellow and red bin, it would go through our machine,” he said.
“It would be processed [and] reduced down into this granulated format.”
Each filter bag contains two types of plastic — an inner pouch made from polyvinyl chloride (PVC) with a plasticiser and an outer pouch made from high-density polyethylene (HDPE).
After the waste has been treated, a float tank is used to separate the denser HDPE residue.
“That in itself is a commodity … it’s a very high-quality plastic,” Pike said. “When you can source separate it like that, you can do several things with it.”
The team has successfully used both PVC and HDPE residues to replace sand aggregate in concrete cylinders. They have also made plastic sheets from the residues with a heat press, and are looking at liquid injection moulding to turn the granules into products like plastic chairs and tables.
Waste on the rise
Medical waste is notoriously difficult to quantify, with many clinics not reporting the amount of waste they produce.
Conservative estimates from 180 Waste Group put the amount of clinical waste produced by Australian public and private hospitals at more than 42,000 t a year. That excludes waste from clinics such as dialysis and veterinary centres.
Pike said one private company he looked at collected more than 500,000 kg of medical waste a year from Australian pathology clinics alone.