NUS students come up with recycling method for medicine strips

Ms Su Yee Shien (left) and Ms Sophia Ding Ning Ke holding medical blister packaging and recovered aluminium and plastic polymer pieces. ST PHOTO: LIM YAOHUI

SINGAPORE - Once the last pill is taken, a patient or nurse will - without giving it a second thought - discard the medicine strip, which is made of polluting plastic and sought-after aluminium.

Medicine strips - formally known as pharmaceutical blister packaging - cannot be recycled because they are made of plastic and aluminium heat-sealed together with a type of glue.

It is difficult to separate the materials in this multi-layer packaging so the strips are usually discarded as general waste.

To avoid having to throw them in the incinerators, a group of engineering students from the National University of Singapore (NUS) came up with a chemical recycling method to separate plastic from aluminium and salvage both components.

Both materials can then be sent to recycling companies.

This student initiative, called the Green Doctors Programme, was born last August when a pharmacist from the National University Hospital (NUH) approached the NUS department of Civil and Environmental Engineering to find a way to reduce medical waste.

Every month, commonly prescribed medicines at NUH account for about 200,000 medicine strips being used up.

Overall, about five million strips are thrown away every month in Singapore, said Ms Sophia Ding, founder of the Green Doctors Programme, and final-year civil and environmental engineering student at NUS.

Chemical recycling involves adding chemicals to the waste materials to break down their original structures.

Ms Ding declined to elaborate on her team's process to salvage the plastic and aluminium in the medicine strips as it is still in the early research phase.

After three months of research, the Green Doctors Programme concocted a recipe to dissolve the adhesive layer between the plastic and aluminium earlier this year, so that the materials can be separated.

The team, which includes about 10 chemical, environmental and mechanical engineering students, has been testing and working to optimise their solution using medicine strips provided by NUH.

"There were only two research papers on recycling medical blister packaging. So it was very difficult for us to come up with the methodology ourselves because we had to infer and go into the roots of the materials," said Ms Ding, 22.

"And we had to think about the technology that goes behind heat-sealing, and how to separate the layers without doing much harm to the original materials."

It is difficult to separate the materials in this multi-layer packaging so the strips are usually discarded as general waste. ST PHOTO: LIM YAOHUI

If all medicine strips in Singapore were to be recycled, 16 tonnes of plastic and 2 tonnes of aluminium could be saved each month, she added.

According to the World Health Organisation, about 85 per cent of all waste from healthcare activities is non-hazardous, general waste.

The remaining 15 per cent is biohazardous waste that is infectious, toxic or radioactive, and must be collected and disposed of safely and carefully to prevent cross-contamination and other public health risks.

In a written answer to a parliamentary question about medical waste in May 2021, former Health Minister Gan Kim Yong said the amount of biohazardous waste generated in Singapore increased from 4,400 tonnes in 2016 to 5,700 tonnes in 2020.

The Covid-19 pandemic exacerbated the issue in 2020, due to additional infection control and biosafety measures.

Mr Gan said hospitals and clinics have been mindful to reduce and recycle non-biohazardous waste, including packaging for sterile equipment, fluids, and glove wrappings.

Professor Seeram Ramakrishna, chair of the NUS Circular Economy Taskforce, said much suitable medical or pharmaceutical waste is not recycled due to the challenges in segregating and pre-cleaning before recycling, in case it is biohazardous.

But he noted that recycling industries are keen on trying to recycle plastics and other disposables, which have been treated and certified as non-biohazardous.

Recently, hospitals and healthcare players here have been taking gradual steps to reduce their medical disposables and recycle them.

Since 2020, the Singapore General Hospital has been sending stainless steel disposables - such as surgical instruments and laryngoscope blades - to vendors for recycling.

The soiled instruments are thoroughly washed and decontaminated in the hospital, and between 450kg and 600kg of instruments are recycled each month.

By 2030, Alexandra Hospital plans to reduce its waste by 60 per cent and raise its recycling rate by the same amount.

The hospital is looking to see if their alcohol-based hand rub bottles can be cleaned so that they can be given to recyclers.

The hospital also has specific bins for staff to drop off plastic packaging, and older operating theatre gowns are turned into recycling bags, said its chief operating officer Jeffrey Chun.

From this year, most companies with an annual turnover of $10 million have to report the amount of packaging they use, and this includes pharmaceutical and medtech companies.

Some companies have developed reusable inhaler devices - where the medicine canister for asthmatic patients can be replaced several times - to move away from disposable inhaler devices, said the Pharmaceutical Society of Singapore.

The Green Doctors Programme also plans to look into how other types of hard-to-recycle medical waste such as IV bags can be recycled.

The pandemic has also made medical waste more visible, with used surgical masks disposed in public places.

Prof Seeram said: "People can opt for reusable masks and face shields, and refillable sanitiser bottles. Provisions to take back unused antigen rapid test kits by pharmacies and retailers can be explored.

"Such simple measures will lower the medical waste footprint."

Join ST's Telegram channel and get the latest breaking news delivered to you.