Bioplastics: A Solution to the Plastic Waste Problem?
Plastics are part of every aspect of our lives. They are in our cars, hospitals, homes, electronics, and they are an integral part of our food supply chain.
Plastics can be shaped into anything and mimic materials that we need (e.g., leather and rubber). They are widely available and affordable. Although plastics remain an important part of our day-to-day, the amount of waste produced from our reliance on plastics and their persistence in natural environments have severely complicated their management and disposal.
Bio-based plastics, which are plastics produced from plants and other renewable sources, show promise in reducing plastic pollution and our reliance on fossils fuels. However, we must consider the trade-offs and benefits of bio-based plastics, how they will fit into our waste management systems and their holistic impacts on human and planetary health.[1,2]
Petroleum-based vs. Bio-based Plastic
Petroleum-based plastics are made from petrochemicals. Bio-based plastics, more commonly known as bioplastics, are derived from biological sources such as starch, cellulose, shrimp shells, and vegetable or animal proteins. Bioplastics are being designed to have the same quality and durability as petroleum-based plastics. However, bioplastics still constitute a small fraction of the market. In 2019, the total production volume of bio-based polymers was only 1% of the production volume of petroleum-based polymers.
Unlike petroleum-based plastics that may take decades or even hundreds of years to degrade, many bioplastics are biodegradable. It is important to note, however, that the origin of a plastic (petroleum-based or bio-based) does not determine whether it is biodegradable or not. For example, petroleum-based plastics can be modified to become biodegradable. While on the other hand, a bioplastic’s structure can be manipulated to closely mimic the physical and chemical makeup of a petroleum-based plastic so that they serve the same function, but this can render them non-biodegradable and not suitable for composting facilities.
What’s Up With Bioplastics?
Bioplastics are being referred to by some as an environmentally friendly plastic because in some cases they can replace their petroleum-based counterparts due to their similar properties (e.g., strength and stability). However, bioplastics are not perfect, as they can create additional pressure on land use, face limitations in biodegrading within composting facilities’ timeframes, and potentially contaminate composting facilities with non-biodegradable additives that are found in some bioplastics. A full understanding of the advantages and challenges associated with the potential transition from petroleum-based to bioplastics should be examined further.
Biodegradation can happen in soil, water, and composting environments. Bioplastics that are classified as compostable – not all are – are designed to breakdown in composting facilities if the conditions align with the required time and environment needed for the plastic to break down. The leftover biomass can be used as compost, creating a circular waste system.
Compostable bioplastics may help address plastic waste challenges, especially for single-use items and mixed-material packaging that cannot be recycled.
In order to fully realize this potential, it is necessary to identify ideal processing conditions to optimize bioplastics’ degradation and the feasibility of creating these conditions, such as adapting existing composting facilities.
Production guidelines, managing protocols, and testing methods have been issued to standardize procedures to verify bioplastics’ compatibility with disposal treatments and the use of their leftover biomass. Governments are becoming more strict with their regulations concerning bioplastics to avoid abuse, ‘greenwashing’ and avert potential contamination of soils and food supply downstream.
Current End of Life
A limited percentage of plastics, petroleum-based and bio-based, are directed to recycling or incinerators with and without energy recovery, resulting in the majority of plastics in Canada ending in a landfill (approx. 86%).
For compostable bioplastics, there are limited facilities that are designed for composting these materials. Most composting facilities are designed for food scraps and have a turnaround time of 45 to 90 days (in some cases even less) which is currently not enough time for many bioplastics to break down. One main barrier to making bio-based, biodegradable plastics decompose faster is the necessity of plastics to withstand environmental factors and remain intact for the length of their intended use. Bioplastics are still at an infancy stage of widespread use. And while there are standards for bioplastic’s biodegradability and compostability (requiring bioplastic packaging to break down within specific timeframe and conditions) waste management facilities do not always follow these requirements.
Potential End of Life Solutions
There is an urgent need for adequate facilities and streams for plastic disposal (both recycling and composting) in countries, such as Canada and the USA, that have astonishingly low plastic recycling rates (~9%). Many plastics, petroleum-based or bio-based, are recyclable. It is important to address the current issue of inadequate waste management in Canada and the USA, especially considering the significant limitations in recycling petroleum-based plastics in these countries.
The inclusion of a new material, such as bioplastics, could amplify the waste problem if the system doesn’t handle those materials.
Germany, South Korea, Austria, and Wales who recycle at least 50% of their municipal waste are exemplar countries that should be looked to for waste management policy, infrastructure, and behavioral change as the targeted global standard.
A major portion of single-use plastics and contaminated food packaging ends up in landfills. This is where compostable bioplastic can play a significant role. To dispose of food waste (e.g., scraps), many municipalities and cities are adopting composting facilities that minimize odor, reduce conversion time, and reduce methane and nitrous oxide emissions. The turnaround time of these facilities is normally too short for effectively composting most bioplastics. Currently, some businesses and organizations have found ways to deal with this problem. For example, the National Arts Centre in Ottawa is directly connected with a composting facility to accommodate the timeframe it will take to process their compostable bioplastic cutlery, cups, and plates. This is a potential model for organizations and companies that generate a significant amount of waste at their facility to shorten their waste chain and ensure the proper disposal of compostable bioplastics.
Other potential solutions include accelerating the biodegrading timeframe for bioplastics so that they can degrade with food scraps. This could be either reducing the lifespan of bioplastics or applying a treatment (e.g., spraying a chemical solution) at composting facilities to speed up biodegradation after-use. High pH (basic) or salt solutions have been tested for this purpose. Such solutions, in addition to high humidity, could enhance degradation speeds in composting facilities.
Potential Policy Options
With 86% of Canada’s plastics going to landfills, it is evident that there is much work to be done to improve the country’s ability to timely and effectively diminish the plastic pollution problem. There is a need for clarity from the municipal governments on what is accepted and what is not accepted at recycling, composting and energy recovery facilities in each jurisdiction. This information can help consumers make better decisions when selecting a product and sorting their waste. Globally, there is a mounting consumer demand for an action plan to reduce plastic pollution.
Bioplastics are a promising solution, but many argue that all countries should be first taking steps to improve existing recycling systems and transition away from single-use plastics.
Some countries and regional jurisdictions have started to implement stricter policies to address the confusion around bioplastics, and particularly to mitigate misinformation from manufactures to consumers using bio-based and biodegradable synonymously. For example, Washington and California have banned the terms “biodegradable” and “compostable” on products that do not have a compostable certification suitable for their facilities, which led to fining Amazon $1.5 million for falsely claiming plastic products as biodegradable. There is no silver bullet to address the plastic pollution problem. A coherent mix of policies and initiatives, from regulations to support for innovation can work together to address this massive problem in Canada. Improved management of plastics should also include bioplastics. Bioplastics are currently a small fraction of the plastics in the system, but they can provide an opportunity to improve the management of plastic waste.
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