Compostable vs. Biodegradable Packaging: What’s the Difference
The importance of why a packaging material should meet the standard of being compostable versus being simply biodegradable, and how industrial composting can help slow global warming.
Why Biodegradable Doesn’t Always Mean Eco-Friendly
It is important for eco-conscious communities to have a true understanding of what meeting the standard of “composability in packaging” really means. Too often, companies claim that their packaging is “biodegradable,” and the consumer may take that claim to mean the material is eco-friendly, when in actuality it is not. This blog will help shed light on what it means when packaging is truly compostable, and how utilizing industrial composting—rather than disposing of items in a landfill—helps to decrease waste and reduce greenhouse gas emissions.
What Makes Packaging Truly Compostable?
First, almost all items will biodegrade over time. Some items, like traditional plastics, can take over 200 years to biodegrade—but they eventually will. Many types of packaging made today are not compostable yet may still be able to be disposed of in other ways, albeit not always eco-friendly. According to the European Bioplastics Industry, composability is a characteristic of a material that enables biodegradation under specific conditions (temperature, time, oxygenation). At the end of this process, only natural products remain (water, carbon, biomass). Not all packaging that biodegrades will do so without leaving remnants such as microplastics and environmentally harmful byproducts.
Composting Standards: ASTM D6400 and EN 13432
A distinction needs to be made between industrial and home composting. The specific criteria defining conditions of industrial composability of packaging materials—including the composting environment, temperature, and time—have been defined by the standards ASTM D6400 (US) and EN 13432 (Europe). When a packaging product meets these standards, the consumer is assured that the material at hand will physically disintegrate into the soil, leaving no traces behind within 180 days. In addition, the final product must pass through a 2 mm screen. These remnants will not contain any heavy metals, and the finished compost will support plant life. Packaging materials complying with this standard can be certified and subsequently labeled with the Seedling label. Historically, ASTM D6400 has been developed for the plastics industry. The standard can also be applied to other solid packaging materials such as paper products, textiles, and other sustainable packaging formats. Further, ASTM D6868 is used for biodegradable laminated plastic film or extruded bioplastics.
Industrial vs. Home Composting for Packaging
Composting is the controlled aerobic (oxygen-requiring) decomposition of organic materials by microorganisms in controlled conditions. It reduces the volume and mass of raw materials while transforming them into a valuable soil conditioner, called compost. Mentions of composting and bioplastics usually refer to industrial composting in a managed composting facility, with the end goal of meeting the ASTM D6400 standards. The main difference between industrial and home/garden composting is that temperatures in industrial composting facilities are much higher and kept stable, whereas the temperature of a home compost is usually lower, less constant, and subject to influence by other factors such as weather conditions. Home composting is a much slower process than industrial composting and involves a comparatively smaller volume of packaging waste.
How Compostable Packaging Decomposes
Biodegradation via industrial composting and landfills naturally produces gases as a byproduct of the bacteria breaking down the materials at hand. However, industrial composting incorporates oxygen (aerobic conditions) through mixing and aerating the waste.
Packaging Waste in Landfills vs. Composting Facilities
Landfills do not mix their waste, and the landfill material is broken down by microorganisms under oxygen-deprived, or anaerobic, conditions. When exposed to oxygen, a distinct variety of microorganisms digest the debris, and as a result, a greater amount of CO2 is produced than when the debris is not oxygenated, thus producing proportionally more methane. Both forms of biodegradation produce greenhouse gases (including CO2, methane, and nitrous oxide), but although it is shorter-lived, methane is about 80 times more harmful to the atmosphere than CO2, because it traps more heat per molecule than CO2 does.
Why Oxygen Matters in Composting Packaging Waste
All greenhouse gases can trap heat in the atmosphere and contribute to global warming. Earth has carbon cycles which help to remove and recycle CO2 and other gases, but when these gases are produced in greater amounts than the environment can remove, we throw off our planet’s natural balance. If current emission rates continue, global warming will surpass 2 degrees Celsius (3.6 degrees Fahrenheit) between 2040 and 2070, which the Intergovernmental Panel on Climate Change deems dangerous.
The Role of Compostable Packaging in Reducing Emissions
Please refer to the upcoming blog discussing the carbon cycle, hierarchy of waste reduction, and how we as manufacturers and consumers can lessen our impact on global packaging waste and greenhouse gas emissions.
