Bioplastics vs. Traditional Plastics
As the world becomes more aware of the harms that plastic pollution is causing, alternatives like bioplastics have emerged to replace petroleum-based single-use products. By now, you’ve probably come across some of these bioplastic products and you may not have even known it. Bioplastics typically look and feel just like regular plastics, but differ in how they’re made and how they break down at the end of their life.
How They’re Made
Conventional plastics are made from non-renewable fossil fuels, such as crude oil, coal, and natural gas. These fossil fuels are refined into petroleum products which are then further broken down into polymers, the building blocks of plastic. This is an energy-intensive process that generates a large amount of greenhouse gas emissions. Conventional plastics are responsible for roughly 3.4% of global greenhouse gas emissions.
Bioplastics are made from renewable plant sources, such as corn and sugarcane. Starch, cellulose, and lactic acid are common components extracted from plant biomass that are used to form the building blocks of bioplastics. Bioplastics tend to release less carbon emissions throughout their lifecycle compared to traditional plastics and, in some cases, they can be produced with no net carbon emissions.
How Plastics and Bioplastics Act in the Environment
Although traditional plastics and bioplastics are made from different materials, they act similarly in the natural environment.
Traditional plastics can take hundreds to thousands of years to break down. Instead of plastics breaking down into natural compounds like carbon dioxide and water, they tend to break up into smaller and smaller pieces called microplastics. These microplastics have been found in the ocean, soil, and even our drinking water. One way to think about this is, all of the plastic that has ever been produced still exists today. Whether plastic ends up in the landfill, ocean, or recycling plant, it has not been broken down into its original components.
The term “bioplastic” implies that a product will degrade in the natural environment within days, weeks, or months, similar to an orange peel or flower petal. Unfortunately, this is not how most commercial bioplastics behave if they become litter. Depending on how the bioplastic is made, it can take several days to several years for them to decompose. If commercially compostable plastics are sent to the landfill or littered, they can take a long time to break down, just like traditional plastics.
Why We Need Commercial Composting Facilities
Compostable plastics, a type of bioplastic, are designed to break down in commercial composting facilities. These composting facilities are able to reach high temperatures and maintain the right moisture levels that are necessary to process compostable plastics into compost. These conditions cannot be maintained in the natural environment so these plastics will not properly decompose without a commercial composting facility. Likewise, compostable plastics cannot easily be broken down in backyard composting piles because they normally do not reach high enough temperatures.
Commercial composting facilities are also able to handle a much larger amount of organic waste than individual or community composting piles. As compostable plastics become a popular replacement for traditional plastics, large-scale composting facilities will be necessary to process the growing amount of organic waste.
It is important to note that not all bioplastics are compostable. Don’t be fooled by greenwashing tactics, if the product is not labeled as ASTM D6400, BPI-certified compostable, or PLA #7, the item cannot be composted in commercial composting facilities. Beware of some products being labeled as “biodegradable”, “bio-based” or “plant-based” because they may be made with a combination of fossil fuel and plant polymers.
How to Tell the Difference
It can be difficult to tell the difference between bioplastics and traditional plastics. Bioplastics have been manufactured to almost blend in with regular plastics so they can be used as a replacement. Typically, these bioplastic alternatives are marked with a green stripe and/or labeled with the material they’re made from. For example, a compostable drink cup will usually be marked on the bottom with the number “7” inside a chasing arrows symbol with “PLA” underneath. Most traditional plastic cups will be marked with only the chasing arrows symbol and the numbers 1, 2, or 5. If an item is not marked with “PLA #7” or a compostable certification, it cannot be composted, even if it labeled as a bio-based material. If you don’t see a clear label are unsure whether it is compostable or not, do not put it in your compost bin because it may contaminate the compostable waste stream. Instead, reach out to us at info@compostnashville.org and we can help determine if it is compostable or not.
Conventional plastics have become one of the top polluters of our environment. Bioplastics and compostable plastics can be a helpful way to prevent more plastic from ending up in our waterways and reduce carbon emissions, so long as we have a way to collect and process them.
If you’re looking for ways to cut down your plastic waste and reduce your carbon emissions, Compost Nashville is here for you! Compost Nashville will accept your food scraps, compostable plastics, and other compostable material and send them to a commercial composting facility where they will be turned into nutrient-rich compost! To learn more, head to our sign up page here.
Sources
https://www.thomasnet.com/articles/plastics-rubber/how-is-plastic-made/
https://www.azom.com/article.aspx?ArticleID=22110
https://news.climate.columbia.edu/2017/12/13/the-truth-about-bioplastics/