As the severity of an extended pandemic is on the rise, the world determines an increasing and never-ending waste stream of used plastic face shields, surgical masks, gowns and medical gloves. Currently, engineers from Cornell University provide a solution to sustainably reroute the thrown-away material.
Image Credit: Shutterstock.com/ Fevziie
As per the study, a medium-temperature reaction known as pyrolysis has the ability to reduce the plasticized medical-protection garb back into its original forms — like petroleum and chemicals — and further recycle it, potentially into fuels.
This technique involves no landfill use or incineration.
The scale of disposing used medical personal protective equipment (PPE) is enormous. Fast pyrolysis is proven to effectively convert waste PPE into value-added products. The pyrolysis method can replace PPE incineration or sending it to landfills, which is what happens now.
Xiang Zhao, Study Author and Doctoral Student, Cornell University
Zhao, who collaborates with his advisor Fengqi You, the Roxanne E. and Michael J. Zak Professor in Energy Systems Engineering, in the Smith School of Chemical and Biomolecular Engineering, reported the suggested technology framework, in January in the journal Renewable and Sustainable Energy Reviews.
The framework — initially concentrating on New York state — suggests gathering waste PPE from hospitals and medical centers, and further sending it to pre-processing and decontamination facilities in New York or Suffolk counties. There, the waste would be shredded, sterilized and then dehydrated to small particles, and further brought to a combined pyrolysis plant, like the one proposed for Rockland County, north of New York City.
Using You and Zhao’s model, the medium-temperature pyrolysis (nearly 1200 °F) could dismantle the plasticized gloves and gowns, derived from petroleum, into chemicals like butane, ethylene, gasoline, propane, bauxite, diesel, propane, light sulfur and naphtha.
For an analogy, pyrolysis is similar to baking in an oven. If you set the oven temperature very high, your meat becomes a chunk and charcoal. But if you use a lower oven temperature, the meat is going to be juicy. In pyrolysis, the temperature is the trick.
Fengqi You, Senior Faculty Fellow, Atkinson Center for Sustainability, Cornell University
All over the world, health care facilities are making nearly 7.5 pounds per person of PPE waste daily via COVID-19-associated services, as per the United Nations Environment Program.
To gain better insights into the enormity of the disposal dilemma, one hospital with 300 medical personnel could produce over a ton of medical garb waste every day. This helps translate to over 400 tons of annual medical PPE waste in a single COVID-handling facility, stated You.
In the study’s energy analysis and environmental lifecycle assessment, the suggested optimal PPE processing system prevents 41.52% of complete landfilling and 47.64% of the incineration processes. This technique illustrates an environmental benefit by decreasing greenhouse gas emissions by 35.42%, emissions from traditional incineration and energy saving by 43.5% from landfilling, stated the scientists.
This is a viable strategy for disposing and processing waste PPE. It is a treatment method with low greenhouse gas emissions, it alleviates fossil fuel emission depletion and it saves a lot of polluting material from landfills.
Fengqi You, Senior Faculty Fellow, Atkinson Center for Sustainability, Cornell University
This study was financially supported by Cornell’s David M. Einhorn Center for Community Engagement and Cornell Atkinson.
Journal Reference:
Zhao, X., et al. (2022) Energy and environmental sustainability of waste personal protective equipment (PPE) treatment under COVID-19. Renewable and Sustainable Energy Reviews. doi.org/10.1016/j.rser.2021.111786.