Sustainable management of plastic waste from hospitals
Hospitals use large amounts of plastics which continue to rise. Most of the plastics are used as disposable items such as plastic syringes, single-use gowns, sterile packaging, etc. due to patient safety, lower cost and convenience. Medical wastes historically have been disposed of in landfills or incinerated. However, politicians and health organizations are beginning to call for a new approach at hospitals that minimizes waste from manufacturing to the disposal. In this context, significantly increased recycling is highlighted as important part of a broader effect to improve hospital sustainability and reduce waste. Products for the healthcare sector are often of high quality and made from high grade plastics, which makes them even more valuable for recycling. However, despite the fact that there is considerable demand for such high-quality plastic waste, the perception that waste generated in hospitals is “dirty” and constitutes a health risk makes people reluctant to use it.
The project goal was to increase recycling rates of hospital plastics waste without increasing workload of the staff and without increasing risks for people or the environment. To achieve this goal, suitable pre-treatment methods were used capable to remove infection risks from the plastic waste fraction viz. a hydrothermal method supplied by RedBag Solutions (RBS) and an ozonation process supplied by Ozonator. The main challenge was to find out how quality of plastics from combustible plastic waste fraction is affected by the different pre-treatment methods but without compromising the total removal of the potential infection risks. Three materials for the experimental study were carefully chosen in consensus with hospitals and product manufacturers: polyethylene (PE) used in aprons, polypropylene (PP) used in medicine cups and syringes and polyvinyl chloride (PVC) used in gloves. After pre-treatments, the materials were evaluated with respect to colour change, degree of stabilization and alteration of chemical structure. The main conclusion from the pre-treatment studies was that the pre-treatment processes do not cause any measurable changes in the materials studied except some indications of a minor plasticizer loss in the PVC samples.
Capability of pre-treated plastics to perform well in industrial processes was evaluated in two large-scale recycling trials. The PP material was used at Bergo Flooring for production of floor tiles made of 100 % recycled PP while the PVC material was used at Tarkett for production of flooring containing 20 w% of recycled PVC. Before manufacturing, the materials were pre-treated in commercial large-scale RBS equipment in USA. The main experience from the trials was that the materials are useful and perform well in the manufacturing process although there is room for improvements that would increase the usability of the recycled materials. One important objective would be to identify and hinder the potential contamination of the pre-treated materials. Another objective would be to ensure a sufficient degree of stabilization of the materials in order to minimize degradation during usage, pre-treatments and recycling processes.
Finally, the pre-treatment technologies and subsequent recycling were evaluated with respect to environmental, economic and social factors. The results show that pre-treatment and recycling is beneficial from a climate perspective, even with assumed material losses and assumed quality reduction of the recycled materials. The environmental credit for recycled plastic materials was given only half of the virgin materials. In the industrial recycling trials a significant part of the virgin materials was replaced by the recycled materials without quality reduction thus the environmental credit should be significantly higher than 0,5. This means that the environmental benefit due to recycling is even higher than calculated by the LCA.