Biodegradable vs. Compostable Products: Do you know your options?
A lot had been said and written about packaging. There is a strong push to switch to compostable and biodegradable packaging, but there is very little understanding of how effective switching to these is. I started doing research and I found it to be a large and complex topic. The following is a highlighted summary of my findings to help clarify and aid in making an informed decision.
What makes a material compostable? (1)
When the products are designed to be composted, they should meet ASTM Standards D6400 (for Compostable Plastics) or ASTM D6868 (for Compostable Packaging). Products that meet the requirements in these two specifications will:
- Disintegrate Rapidly during the composting process (so that no large plastic fragments will wind up on the composters screens when the process is finished).
- Biodegrade quickly under the composting conditions.
- Not reduce the value or utility of the finished compost. The humus manufactured during the composting process will support plant life.
- Not contain high amounts of regulated metals.
What makes a material biodegradable? (2)
Under the right conditions, the microbes in the environment can break down the material and use it as a food source. Biodegradation is a process that can take place in many environments including soils, compost sites, water treatment facilities, in marine environments and even in the human body.
This is the process that converts carbon into energy and maintains life. Not all materials are “biodegradable” under all conditions. Some are susceptible to the microbes found in a wastewater treatment plant, while others need the conditions and microbes found in a compost pile or in the soils.
Most biodegradable products sold need “the right conditions” present in commercial composting facilities where heat, moisture or other chemical process is used to breakdown the plastic first, before the biodegradation can take place. No, you cannot put these plastics in a yard composter and expect the same results.
Biodegradable does not mean compostable
There are not equivalent. Any plastic will over time breakdown (or biodegrade) into smaller pieces, but remain just that – small pieces of plastic (just like micorbeads). The critical distinction here is that the end result of composting Must Support Plant Life – ie. it must be soil.
The only way to be sure that the plastic/packaging you are choosing is truly compostable is ASTM (or other verification institute) certification where product is tested in conditions composting facilities would provide. Foodservice Packaging Institute has released Strategic Sourcing Guide(3) with a list of questions for potential packaging supplier. Knowing how to choose biodegradable/compostable materials is just one side of the equations.
The next question is “Does your local composting facility have right conditions to process biodegradable materials?”
Before we even delve into this topic, we must be reminded that landfills do no allow presence of air in piles of waste. This mean that even food will lay buried and untouched by decomposition for decades. Should any of the compostable plastic find its way to landfill, it will be acting no different from petroleum-based plastics – laying in the piles for decades without decomposing. The best of consumers intentions (and money) would be wasted should the products find their way into landfill.
Unlike compostable plastics, there is a lack of standardization for biodegradable materials. This causes confusion among consumers and composters alike. To make matters worse, starch-based, plant based, and made from “renewable” materials are added to the mix. They may all be biodegradable / compostable but the process may take different lengths of time. This makes it difficult to process some of the materials and they would not be accepted in the local composting facility.
In many ways, compostable plastics demand and production are developing faster than the public regulatory agencies that support this industry, creating a disconnect between plastics manufacturers, consumers, regulators and commercial composers.(4)
Be sure to check with your waste collector what materials are currently accepted by composting facility in your area before making your decision on what products to purchase.
Remember !!! – The most sustainable waste is the one you never made.
Should you still have some “not needed resources” aka waste, then try to find a useful place for these in the following order:
1) Re-use (beer bottles, jars, plastic bins and containers, boxes etc)
2) Re-purpose (upcycling – giving a new function to used products – refurbishing electronics, using for art etc)
3) Re-cycle (downcycling – converting materials and products into new materials of lesser quality 4)
1BPI – Confused by the terms Biodegradable & Biobased
2 Foodservice Packaging Institute: Strategic Sourcing Guide
3 The California Organics Recycling Council : Compostable Plastics 101
4 Wikipedia definition of Downcycling and Upcycling