Sometimes deciding what or how to recycle an item can be difficult. In this post we’ll look bioplastics, biodegradables, and compostables. Tomorrow, we’ll look at plastics, electronic waste and paper.
Oftentimes, the terms bioplastics, biodegradables, and compostables are used interchangeably. They do not really all mean the same thing however.
Let’s start with biodegradables. What exactly constitutes a biodegradable product? Biodegradable products, such as plates and cutlery, can now be found on most store shelves. Biodegradation is the process of biological conversion of materials into CO2, H2O and minerals. According to tests based on international standards (OECD), to be called readily biodegradable an ingredient must biodegrade 60% or more within a 28-day period.
Conventional plastics such as polyethylene and polystyrene are derived from fossil fuels. Biodegradeable plastics (which are not bioplastics), can break down under certain circumstances, and are derived from either agricultural or petrochemical sources. While a material can be labeled biodegradable (referring to the process whereby microorganisms cause decomposition and assimilation), it may not necessarily be compostable, the process by which material biodegrades to produce carbon dioxide, water and humus within a specified period of time. According to World Centric, “Biodegradable plastic is plastic which will degrade from naturally occurring microorganisms, such as bacteria, fungi etc. over a period of time. Note, that there is no requirement for leaving ‘no toxic residue,’ and as well as no requirement for the time it needs to take to biodegrade.”
In addition to ‘biodegradable’ and ‘compostable,’ there are new greener products coming into the marketplace with labels such as oxo-biodegradeable, hydro-biodegradable, photo-biodegradable or water soluble, which speaks to the chemical process by which these materials break down. The bottom line is, not all biodegradable plastics are created equal and there are a lot of misleading claims out there. To figure out which ones will really break down, look for the “Compostable Logo,” designed by the New York City-based Biodegradable Products Institute (BPI) and the U.S. Composting Council. It identifies products that meet industry standards to break down quickly and completely in a municipal compost facility. 
Compostable plastic is plastic which is “capable of undergoing biological decomposition in a compost site as part of an available program, such that the plastic is not visually distinguishable and breaks down to carbon dioxide, water, inorganic compounds, and biomass, at a rate consistent with known compostable materials (e.g. cellulose) and leaves no toxic residue.” American Society for Testing & Materials (ASTM).
According to World Centric, “In order for a plastic to be called compostable, three (3) criteria must be met:
1. Biodegrade – break down into carbon dioxide, water and biomass at the same rate as cellulose (paper).
2. Disintegrate – the material is indistinguishable in the compost, that it is not visible and needs to be screened out.
3. No Eco-toxicity – the biodegradation does not produce any toxic material and the compost can support plant growth.”
Bioplastics, such as polylactic acid (PLA), are made from renewable resources such as starch from corn or sugar cane. Bioplastic products are usually made from agricultural waste materials. PLA products are made from corn starch, from No. 2 yellow dent field corn, the most abundant and cheapest source of fermentable sugar in the US. Bagasse products are made from residual sugar cane fiber (a waste product of sugar production). According to World Centric, “Bagasse products, which are made from sugar cane fiber leftover from juice extraction, are very sustainable products. It uses a waste product that would otherwise be landfilled or incinerated.”
Any item which is intended to decompose must be disposed of properly in order to be of benefit to the environment. This means these items cannot be thrown into your trash. Many people believe that by purchasing “biodegradable” products, they are helping the environment. If those products end up in a landfill, they just add to the mounting garbage. Nothing biodegrades in a landfill because they aren’t supposed to. Landfills are not compost piles! According to the U.S. Environmental Protection Agency, “Modern landfills are well-engineered facilities that are located, designed, operated, and monitored to ensure compliance with federal regulations. Solid waste landfills must be designed to protect the environment from contaminants which may be present in the solid waste stream. The landfill siting plan—which prevents the siting of landfills in environmentally-sensitive areas—as well as on-site environmental monitoring systems—which monitor for any sign of groundwater contamination and for landfill gas—provide additional safeguards.”
According to the findings of Dr. William Rathje in his 1991 book Rubbish!: The Archeology of Garbage, the dry and oxygen-poor conditions found in modern landfills cause organic matter to mummify rather than decompose. This is preferred since uncontrolled biodegradation in a landfill could cause ground water pollution, methane gas emissions, and unstable sub-soil conditions. As a result, modern landfills are kept dry and air-tight to prevent biodegradation. According to the Biodegradable Products Institute, “the phrase biodegradable, like recyclable, merely describes the composition of a product. Its potential, not its inherent value. If a product is sent to a landfill, and not disposed of properly in a municipal composting or recycling facility, it is still part of the problem no matter what it’s made from.”
Biodegradable products belong in the green bin, not the trash, and certainly not the blue box (biodegradable plastic and recycled plastic don’t mix). Biodegradables are best disposed of in a commercial composting system, as commercial compost piles contain large amounts of moisture, are kept at a high heat and are aerated frequently. In commercial composting systems bioplastics are expected to degrade within 180 days. Within a home composting system, where high levels of heat are not able to be reached and where aeration depends on how often the owner is willing to turn their pile, bioplastics can take more than 180 days to degrade. Another factor is product thickness. The thicker a product is the longer it will take to degrade. Many commercial facilities grind or cut products such as biodegradable cutlery in smaller pieces to decrease degradation time. Contact your local waste management facility to inquire about their policy on green waste and composting.
If you do not have access to a commercial composting system (apparently, there still aren’t that many of them around and many do not want bioplastic products), the question then becomes how your purchase of bioplastics helps the environment. In my opinion, knowing that your items will not be composted, the best solution would be to go back to the first R–reduce–and not purchase these products at all. Instead, do as our grandparents and great-grandparents did–use reusable utensils and plates. If, however, there are times when bioplastics are necessary, then the question becomes whether or not it’s worth the extra cost to purchase the bioplastics. One reason to go ahead and purchase them is that you are buying products which have not been made from petroleum, a nonrenewable resource that is in short supply! This though does become a personal decision, knowing that your item will end up in a landfill, mummified along with all the other garbage.
