Have you ever been given a single-use plastic product that was labeled "compostable" or "biodegradable" with a little symbol on it? They typically look and feel identical to regular plastic products, but market themselves as an eco-friendly alternative. People often ask if these can go in your curbside green bin here in SLO County, and the answer is NO!

So why don’t we want these in the green bin, even if they tell us they’re compostable?

First, we need to define some commonly used terms surrounding these products. Some call themselves biodegradable. That just means that, under unspecified conditions and timeframes, they can be broken down by microorganisms. Another term commonly used is compostable. Compostable, in reference to plastic products, means that it can biodegrade by human processing under a specific condition.  Compostability claims are usually coupled with a certification from a third-party organization, the most common one being BPI.

Bioplastic or plant-based are also frequently used on plastics labels. This typically means that the plastic comes from plants, rather than petroleum like conventional plastics. This can refer to a wide range of chemical compositions, and can be made from materials like corn or sugars. Most of these types of plastics are chemically identical to regular plastics, and may behave the same when they degrade.

Does this all sound a little confusing? We think so too. These so-called "eco-friendly" plastics are still new, and their end of life in landfills, compost operations and natural environments hasn't been fully studied.

So why can't our local facilities accept them? There are a few reasons why we ask for you to keep these out of the green organics bin and blue recycling bin.

1. They take a long time to biodegrade.

The leading certifiers, like BPI, test products in a laboratory setting to determine compostability. The most common standards can allow for disintegration within 12 weeks, meanwhile our organic material gets turned into compost/energy in 2 weeks. In that 2 week window, "compostable" plastics would be still intact pieces of plastic floating in the compost. And even if they do degrade, they can dissolve into microplastics that then enter our waterways when applied as compost.

2. Our facilities would lose their organic certification.

The facilities in SLO County that process our organic waste produce organic, OMRI certified compost. OMRI certified compost can be used to grow organic certified produce on our local farms, and helps to keep our farms healthy and productive. If they were to accept "compostable" plastics, they would lose their OMRI certification.

3. It's hard to distinguish between look-alikes.

There are so many plastic products out there that are labeled with a wide range of claims, from "compostable" to "biodegradable" to "eco-friendly". Even if certain types of these products were able to be processed by the facilities, they look identical to ones that aren't able to be processed. The facility operators have no way of knowing what a plastic bag is made of when it goes through the sorting process, so they pull out anything that looks like a contaminant.

4. They can't be recycled with regular plastics in the blue bin.

Any sort of plant-based plastic are not accepted in our blue bin recycling stream as well. Recyclers are equipped to process hard plastic to-go cups, takeout containers and more, when they are made of conventional, petroleum based plastics. Plant-based plastics behave differently in the plastic recycling process, and can prevent regular plastics from being recycled effectively.

So please, put "compostable" plastics in the trash.

It's great to look for sustainable alternatives to the single-use items that we use on a daily basis, but single-use "compostable" plastic is still single-use! Compostable plastics, right now, are not the magic solution to our waste problem.

Instead, look to reusables, like using metal utensils instead of single use ones, using reusable produce bags instead of those "compostable" ones at the grocery store, or bringing your own cup to the café instead of getting one to-go. In terms of single-use items, look for truly recyclable/compostable alternatives, like using wooden chopsticks which can truly be composted locally, or paper bags to collect your food scraps instead of a green plastic "biobag".