Dialysis patients could inadvertently improve sustainability in the construction industry, thanks to an innovative Deakin University recycling project that’s turning hospital waste into longer-lasting concrete.
A team from Deakin’s School of Engineering is behind the new project, which could ultimately save from the scrap heap the thousands of tonnes of plastic waste created in Australia each year through dialysis treatment.
Project leader Dr. Riyadh Al-Ameri, a senior lecturer in structural engineering from the university, leads the project team from Deakin’s School of Engineering, which is working in collaboration with a number of other stakeholders. These include nephrologists Dr. Katherine Barraclough from the Royal Melbourne Hospital and Professor John Agar from Barwon Health’s University Hospital Geelong.
The idea for the initiative came about when the medical specialists approached Deakin to find a practical solution to their waste issue. Not only does the project have the potential to save thousands of tonnes of plastic waste created in Australia each year through dialysis treatment going to scrap, it may also help solve the issue of steel bar corrosion in concrete construction. “Concrete can crack and damage the internal bond, which can then lead to water penetration and corrosion of the steel bars, critical for providing the strength and integrity of concrete structures,” Dr. Al-Ameri says. The project team hoped to use the shredded plastic waste to help better protect structural concrete from corrosion.
“If we are able to facilitate production of new types of concrete that will offer better protection, give structures longer life and better performance, as well as help recycle plastic waste, that will be a great achievement.”
Dr. Barraclough says each dialysis treatment creates between one and three kilograms of plastic waste. With more than 12,000 Australians on dialysis, this adds up to about 5100 tonnes of plastic waste per year.
“Haemodialysis (the most common type of dialysis) involves making a circuit where blood is pumped from a patient’s bloodstream through a machine then back to the patient. This removes toxins and excess water and is life sustaining for patients with kidney failure,” she says.
“For safety reasons, both the tubes that carry the blood and the dialyser (the part of the machine that cleans the blood) are made of plastic designed for single use only. The result is large amounts of plastic waste generated from each dialysis treatment.
“Because the waste is potentially infectious, it must be either burnt or sterilised before being thrown away.”
Dr. Barraclough says this not only costs a lot of money, but also causes significant harm to the environment. “With increasing numbers of people requiring dialysis in Australia and worldwide, we need to work out ways to reduce the costs of care delivery, as well as play our part in ensuring a healthy environment for future generations.”
During initial testing, Dr. Al-Ameri’s team added the shredded plastic waste to a concrete mix at concentrations of 0.5 per cent and one per cent by weight of concrete, with results showing this made a product that was more durable and significantly more waterproof. “The 30 per cent decrease in water absorption we found is significant and would be expected to improve resistance of concrete to corrosion,” he adds.
Due to funding from its industry partner Fresenius Medical Care – a global provider of dialysis products and services – Dr. Al-Ameri and his team hope to conduct more rigorous testing to see if this new concrete mix can stand up to harsh conditions. “We will use our accelerated weather corrosion tanks in the concrete lab to simulate a marine environment,” he says. “One month in the lab is equivalent to approximately one year outside, so we can observe the behaviour of the material quickly and efficiently.
Dr. Al-Ameri explains that wet and dry cycles can have a big impact on the durability of the concrete, as well as chloride in sea water, which is harmful to concrete and steel reinforcement. “So we’re looking for innovations that will help concrete construction of offshore rigs for oil and gas, observation towers, concrete buildings in coastal areas that are exposed to humidity, and marine structures such as retaining walls that are in contact with water.”
*Photos courtesy of Deakin University (Donna Squire)