While the focus is understandably on providing frontline personnel with PPE to safeguard their health, we also urgently need to scale up our capacity for safely processing used PPE, which is made from non-biodegradable, single-use plastics. Dr Mrigank Warrier takes a deep-dive into the scale of the PPE waste problem, and what can be done to mitigate it.
We are sitting on a ticking time-bomb, and it’s not just the pandemic that might explode. Until the latter began, single-use plastics (SUPs) were frowned upon; we didn’t want to use them, we were trying to find ways to get rid of them safely, and we had begun to find substitutes that could have eventually phased them out forever. Then the virus struck, and every healthcare facility in the world — from the smallest rural clinic to the most mammoth corporate hospital began a desperate search for SUPs — in the form of PPE.
Since the Covid-19 outbreak, the increase in the production of plastic-based PPE equipment has been rapid. For example, between 2016 and 2020, the compound annual rate of increase in the global market for PPE was 6.5%, from approximately $40 billion to $58 billion. In 2020 alone, the World Health Organization has projected that PPE supplies must increase by 40% monthly to deal effectively with the pandemic. Even after a vaccine is approved and cases begin to decline, the demand for PPE is not expected to decline substantially; it is predicted to rise at an estimated compound annual growth rate of 20% in facial and surgical masks supply from 2020 to 2025.
At the peak of the pandemic in its origin — Wuhan (China) — the city produced approximately 240 tonnes of medical waste daily — six times higher than before the disease outbreak. The local waste management agencies had to deploy mobile incinerators in the city to dispose of the unprecedented quantities of discarded face masks, gloves, and other contaminated single-use protective gear.
Hong Kong is well-known for controlling its caseload because its residents are rigorous in wearing face masks; more than seven million masks are used and thrown away after a single-use every day. There are published reports of discarded masks in the ocean and on Hong Kong’s beaches and nature trails.
Apart from the increased use and disposal of PPE and plastic bags, other SUPs are being used extensively by some business sectors while restarting their activities in a post-pandemic scenario, such as microfiber wipes for cleaning, disposable feet protection, head caps and cuffs to enter/work in healthcare clinics and beauty salons, and protective plastic films/protectors in chairs, payment machines, balcony/desk, to avoid potential contamination by air droplets, which is replaced after business hours.
According to most estimates, between March and October, India has generated 18,000 tonnes of PPE waste. As lockdown restrictions are eased, more businesses reopen and more PPE is required (perhaps also in anticipation of a second wave), this amount is set to increase exponentially.
What happens to PPE waste?
The potential to recover polymers from mixed healthcare waste, including PPE, is challenging. Recycling without risking infection of individuals working as recyclers in middle- and low-income countries is limited by the low proportion (15-25%) of healthcare waste that is not contaminated. Due to the persistence and high contagiousness of coronavirus, many countries are classifying all hospital waste as infectious.
Improper disposal or handling of contaminated waste can transmit viral pathogens to healthcare and recycling workers. For example, it has been estimated that up to 30% of hepatitis B, 1-3% of hepatitis C, and 0.3% of HIV cases have been communicated from patients to healthcare workers due to improper disposal of medical waste. While we do not yet have numbers for the same when it comes to Covid19, we should not wait to find out.
At present, plastic-based PPE discarded from households is mixed with other domestic plastic wastes. Polypropylene is a common constituent of PPEs such as N-95 masks, protective suits, gloves, and medical face shields. Masks are made of nonwoven materials (e.g., spun bond and melt blown spun bond), often incorporating polypropylene and polyethylene and will likely degrade into smaller microplastic pieces.
Most PPE are lightweight and if discarded in open dumps, can be easily carried by wind and surface currents, quickly spreading to natural environments nearby, threatening land and sea environments. According to a recent report, over 10 million masks can be introduced into the environment monthly, considering an incorrect disposal of only 1%. Assuming that each mask weighs approximately 3-4g, it would result in 30-40,000kg of masks in natural environments.
Ideally, medical waste must be incinerated at 700°C scrubbing and filtering particulate matter, followed by landfilling of residual ash. Urban India was already struggling to safely process biomedical waste before the pandemic; no one knows where the increased volumes being generated now are going. There is no denying that PPE and disposable masks is the need of the hour; however, when it comes to discussing its fate after use, we are like ostriches in the sand, hoping for an out of sight, out of mind situation.
The reality is that much used PPE is being indiscriminately dumped on fallow land, and burnt willy-nilly. Uncontrolled incineration of PPE contributes to the release of GHG, as well as other potentially dangerous compounds, such heavy metals, dioxins, PCBs and furan.
Such polymers are derived from fossil fuel (non-renewable) resources used to manufacture plastic PPE, and degrade very slowly in open environments. Besides, they are among the most commonly found polymers found in terrestrial and marine debris and are known to harm several aquatic species.
Can PPE be reused?
Ideally no. However, some countries have begun to acknowledge their growing mounds of PPE waste, and understand that using single-use PPE is not a sustainable practice. New research since the beginning of the pandemic indicates that PPE disinfection and reuse is possible on a large scale through methods such as infusion of hydrogen peroxide vapor, ultraviolet or gamma-irradiation, moist heat, ethylene oxide gasification, application of spray-on disinfectants, and infusion of base materials with antimicrobial nanoparticles
The CDC’s National Institute for Occupational Safety and Health has stated that before using any decontamination method, it should be evaluated for its ability to retain filtration performance, fit characteristics achieved prior to decontamination, and safety for the wearer (by inactivating SARS-CoV-2).
For high volumes of infectious medical waste (>10 tonnes/day), incineration continues to be the best option as it completely kills pathogens due to the high-temperature applied. If the amount of medical waste is not too high (<10 tonnes/day), chemical disinfection (i.e., use of chemical disinfectants) or physical disinfection (microwave or high temperature steam) might be an option.
That we need to manufacture and use PPE that can be used more than just once is a given. The first company which invests in research to produce this and gets its product validated, will be the first off, the block into a market that is hungry for such options.
Bio-plastics: an alternative
Bio-based plastics are emerging as a sustainable solution, but their market share is very less, mostly due to the low cost of fossil-based plastics and the undeveloped recycling/disposal routes. The use of biorefinery as a biotechnological tool to obtain raw materials from biomass by-products and waste flows (both organic and gaseous) overcomes the need of land and has the potential to increase production patterns, thus decreasing the price of such solutions.
The development of bio-based plastics with identical physical properties to fuel-based plastics would be of interest for the production of face shields, respirators, ventilators, syringes, and boots during pandemic scenarios, as it would allow their reuse or their processing (and thus increasing energy recovery) in the existing infrastructure after proper decontamination. On the other hand, the development of bio-based and biodegradable solutions for masks, gloves and other disposable plastics would decrease their environmental impact when considering landfill or waste-to-energy options.
