The incineration of single-use plastic consumables and devices in laboratories after just one use leads to the waste of high-quality plastic materials, and hence to the waste of valuable resources. It was an observation that led the Clinical Microbiology laboratory at Odense University Hospital (OUH) in the Region of Southern Denmark, to attempt to find an alternative means of disposal for these products.
To that end, a feasibility study was conceived and conducted with a focus on the extent to which PET material from blood collection tubes used in healthcare settings could be recovered and recycled without compromising hygiene, safety or quality of the material. It was decided to focus on blood collection tubes as these constitute a homogenous source of high-quality PET material. In the Region of Southern Denmark alone, seven million tubes are used and incinerated every year. This adds up to an annual total of some 21 tonnes of PET plastic. In fact, by transitioning from incineration to recycling, it was calculated that 33 tonnes of high-quality plastic would be diverted from incineration in the region each year.
OUH collaborated on the study with partners from across the value chain. These included the Health Innovation Centre of Southern Denmark (SDSI) and BD, a global supplier of numerous single-use plastic devices, who joined the consortium through its Sustainable Medical Technology Institute (SMTI) to address environmental concerns and meet customers' sustainability needs. As Amit Limaye, director of the BD Sustainable Medical Technology Institute, explained: "Single-use plastic revolutionized health care, but we know there are environmental considerations that come with this critical innovation.”
Another participant was the Danish Technological Institute, that contributed expertise in materials recovery and microbiological testing. Lastly, GMAF Circular Medico/EcoFITT, which has a proven track record in producing and recycling medical devices, also became a partner.
Used blood collection tubes are considered biohazardous and regulated medical waste, and in Denmark, are currently incinerated after use. Made from PET, they cannot be cleaned and reused like some other medical devices made of glass or metal, even though PET plastic in itself is not only highly suitable for recycling but is one of the most recycled plastic materials today.
Asked why that was, I was told that, while, due to similar container requirements, both PET bottles and blood test tubes are made from bottle-grade PET, blood test tubes are not used for food contact. Most PET recyclers focus only on food contact packaging such as bottles or trays. Used plastic blood collection tubes contain remnants of blood, which in some cases can also contain carriers of infection and blood collection tubes also often have an internal anticoagulant coating, which is removed during cleaning and decontamination. In an appeal to the recycling community, the study participants hope to be able to find recyclers ‘who might find the PET fraction valuable anyhow,’ said Peter Sommer-Larsen, business manager at the Danish Technological Institute.
Contamination challenges
The researchers conducting the pilot study tested different methods for cleaning, shredding, washing, drying, and recycling the blood test tube PET waste.
The initial cleaning test carried out demonstrated that with the methods used, the microbial load could be lowered, but that microbial levels still remained too high. Heat treatment reduced the microbial load to below the detection limit, although the environmental impact of the process made this an undesirable choice. More research is needed to identify the most effective cleaning methods that can improve the quality of the material, meet hygiene regulations and standards, and reduce the environmental and climate footprint.
Blood collection tubes are typically also extensively labelled – another contamination source. The researchers found that the established industry washing and drying process for removing labels also worked on blood collection tubes – but only on shredded tubes, as when the tubes were left whole, label debris clumped together inside the tubes.
Could dissolvable labels offer a solution? “Dissolvable labels were not specifically considered. However, in a larger study we plan to test different types and adhesions of labels. The partner developing the cleaning and disinfection technology is aware of dissolvable labels but only for products with a different label-to-product weight ratio. Blood collection tubes typically have a standard paper label with an additional local label added on top, making the labels' weight about 20% of the total weight,” said Sommer-Larsen.
On the plus side, he did say that the caps used on the tubes were not an issue, even though made from a different material, as the automated analysis procedures in clinical biochemistry labs make removing and collecting the caps early in the process possible.
“Both caps and sealant are valuable and easy to recycle. However, colour sorting is essential as caps come in various colours indicating their use,” he said.