Bioplastics, Part 3: Commercial Composting

We breathe that sigh of relief when we find that next plastic alternative. These days, compostable products are growing in popularity. We get excited when imagining a plastic-free world.

You can learn about the different types in Part 1 of our Bioplastics series, Breaking Down PLA, PHA, and PHB.

Then you can check out the The Full Environmental Picture in Part 2 to learn how eco-friendly bioplastics really are.

And if you’re ready to dive into the composting...read on!

Understanding Bioplastics

Many “plastic” products today are made from vegetable fats and oils, corn starch, straw, sugarcane, and wood-based waste. Together, they are commonly referred to as bioplastics.

On packages and labels, we see things like:

BPI certified compostable
ASTM D6400 certified
Derived from corn
100% compostable
Made from plants
0 carbon footprint
Renewable and BPA-free
No petroleum-based products
USDA certified biobased product

However, it’s a bit of a trap to assume that just because something is made of plant matter that it’s backyard compostable.

Also on labels (usually with asterisks) are lines such as:

Commercially compostable where available
Please compost in a commercial composting system
Appropriate commercial composting may not exist in your area
Please check with local officials

Okay...so now what?

The reality is, there is more than meets the eye when it comes to “compostable” on product labels.

It’s not necessarily misleading, just nuanced.

How Backyard Composting Works

Technically speaking, to be compostable means that microorganisms will break down a substance into ONLY carbon dioxide, water, inorganic compounds (i.e. natural minerals), and biomass, which is organic waste matter safe for the environment. No toxic residue remains.

In our backyard or garden, we can add yard waste and kitchen food scraps to a large pile. Natural microorganisms in the surrounding soil will break it down through aerobic respiration. We need air (namely oxygen) and moisture (from water) for healthy composting.

This is why most compost piles require regular, active turning with a pitchfork or shovel to support a healthy air and water flow.

The result is a fiber-rich, carbon-filled humus (pronounced HYOO-mus), which also contains inorganic nutrients like nitrogen, phosphorus and potassium.

Some carbon dioxide is released into the atmosphere during this process, and temperatures can rise to nearly 150 degrees in the average backyard pile.

How Large-Scale Composting Works

Industrial or commercial composting facilities usually use one of three techniques:

1. Windrow
This open-air process creates long, five-foot-high piles of compostable materials called “windrows.” These are regularly turned so that all material has a change to break down from natural bacteria in the warmer pile centers. This is best suited for yard waste.

2. In-Vessel
This more compact method utilizes large drums, like silos, to control temperature, moisture levels, and aeration. Compostable materials are turned so that bacterial activity reaches all components over time.

3. Aerated Stack Piles
Large compost piles, separated by wood chips, shredded newspaper, or a network of pipes help facilitate airflow. These piles decompose much like windrows, but without the need to manually turn over the materials.

You can check out how American Organics, Athens Services' compost facility in Victorville, CA, utilizes aerated stack piles:

Suffices to say, the compost site for bioplastics is not your backyard garden...

Biodegradability of bioplastics remains an exciting advantage, but most need high temperature industrial composting facilities to break down. These do not exist in every city, and in fact, the nearest one may not even lie within county lines.

Finding My Composting Site

Your first and best option is to research which plastics your local waste management company accepts.

(HINT: For reference, flip to the back label or bottom of the plastic container to find the number, usually 1-7, in recyclable arrows.)

With that handy, try searching:

“what numbers can be recycled near me”

If your local waste management company handles plastics 1-7, you are in great shape. These companies will ship (or sell) your bioplastics to a commercial composting facility, where they will live on to create new bioplastics.

Be sure to rinse your plastics before recycling to avoid contamination. Otherwise, you risk your recyclables being sent straight to a landfill.

If your local waste management company proves to be a dead end, Biodegradable Products Institute (BPI), created a Find A Composter database.

It’s currently being redeveloped, but you can still search for your nearest industrial or commercial composting facility.

(HINT: Try holding down the CTRL key while scrolling to find more locations than typing in a search.)

If a facility is within a reasonable distance, consider collecting, cleaning, and transporting your own bioplastics to that location, periodically. If that’s not doable, stick to reusable containers or only the plastics your local municipalities have committed to recycling safely.

🌊🌊🌊🌊🌊 

Our hope is to inspire people to perform their own small-scale beach cleanups whenever they visit our beautiful oceans. Every bit helps, so we hope you join the community and share your stories.

Thanks, and we’ll see you on the next wave!

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