Biodegradable v Compostable

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Let’s start with compostable materials…

There are currently two primary types of compostable materials in New Zealand: certified commercially compostable and home compostable. certified commercially compostable material is the most commonly used in large volumes. These products are usually made of plant based materials and hold a Code 7 (in the little recycle triangle) as their rating.  

#7/PLA — indicates a plant-based resin that will degrade under certain conditions. Unfortunately, a landfill isn’t one of them, though that’s where most of them end up. They’re not very “biodegradable” in the wild, either. In truth, few communities recycle any Code 7 plastics, but at Eventfinda Stadium our #& products are commercially composted which takes advantage of the #7 characteristic.

Biodegradable?

All products are biodegradable, its just that some take 6,000 years to biodegrade. We do not allow biodegradable products to be sold at Eventfinda Stadium.

What about Compostable?

Compostable has no set standard to it. This means products that may claim to be compostable actually cannot be composted in the facilities we use. Common mistakes include the assumption that inks which are printed on packaging or glues are compostable. These are not compostable therefore the product cannot be composted at our facility.

So, what does this mean?

Commercially certified products break down much faster than conventional materials, but only in specific conditions and environments. An industrial composting facility exposes them to heat and different bacteria and also aerates the materials for sufficient oxidization.

This sounds great, why isn’t everyone doing this?

There are limited facilities in Auckland and only certain facilities can access them. There is also very limited infrastructure for green waste and if products find themselves in there, the facility must send the whole lot to landfill as they are unable to separate the products from the rest of the green waste. In landfill, the products and green waste break down and create methane gas and carbon dioxide into the environment (greenhouse gases – which a commercial composting facility would capture).

What is the solution?

At Eventfinda Stadium we have a relationship with Green Gorilla who own the largest commercial composting facility in Auckland. Where a #7 product finds itself at this facility it is shredded, heated, airated and blended before being onsold (approximately 16 weeks later) as fertiliser and mulch to market gardens.


More information

 

The international coding system currently used for plastic products identification is less than ideal.  It was originally designed for the plastics industry, not consumers. Codes are often hard to find and barely legible, and when it comes to compostable plastics — confusing.

As most folks know, plastics carry various recycling symbols to indicate resin type. For compostable plastics, look for the No. 7 symbol inside a triangle of chasing arrows.

Unfortunately, this is a catch-all category for plastics not otherwise classified, which lumps compostables in with non-compostables like plastic lumber and safety glasses.  So in addition to the No. 7, compostable plastic also carries the letters “PLA” below the No. 7.

If the plastic is marked No. 7 and “O” or “Other,” do not throw it in the compost bin.

Another label to look for is the “compostable” certification label of the U.S. Composting Council and Biodegradable Products Institute. There are multiple variations of this label in circulation. Each indicates that the plastics used meet ASTM specifications D6400 or D6868 for compostable products as tested and certified by ASTM International, a standards organization.

In Europe, where there are multiple certification agencies, the standard to look for is EN 13432/EN 14995, indicated by the “seedling” symbol.

Be aware that “green” is a ticket to higher sales in the marketplace. In the absence of regulations, products sometimes claim to be compostable (or otherwise degradable) without having been tested and certified. To be sure you are purchasing a compostable plastic, look for certification from a legitimate testing agency.

But also know that some manufacturers have certified their products, but choose to design and use their own “compostable” symbols.  Irish cup manufacturer Down2Earth Materials is one example.

When in doubt, check the manufacturer’s website or read fine print on packaging to see if any certifications are mentioned.

‘Compostable’ may not be right for home systems

For the home composter, few compostable plastics are appropriate for the backyard compost pile. In truth, the composting methods used by most municipal and commercial facilities can’t handle “compostable” plastics, either. Of the nearly 5,000 composting facilities in the U.S., only a handful utilize the robust, high-rate technologies required.

Generally, an industrial composting facility is needed to successfully compost these industrial resins.

The U.S. Composting Council has model legislation for states to use in developing regulations governing labeling and certification for compostable plastics. This document may be viewed/downloaded from the Council’s Compostable Plastics Task Force page.  It includes a special label to indicate suitability for home composting.

The “OK Home” label and certification is already in use in Europe.  It indicates products that can compost at the lower temperatures common to backyard composting environments. The certification entity, Vinçotte, has been verifying compostables since 1995.

Biodegradable vs. compostable

A rock may “degrade,” but it’s not compostable. A plastic may be “compostable,” but it won’t biodegrade in water or soil. When it comes to the semantics of the plastics business, the use of specific words or terms printed on labels may not be generic or interchangeable.

Terms don’t always conform to industry standards. Product claims may not result from testing and certification. To ensure you’re paying for the right product, look for a legitimate “compostable” label and certification.

      • If you are uncertain as to the compostability of the plastic —
      • If your locale is not serviced by a facility that can process compostables —
      • If the plastic is not certified for your home compost bin —

then a more traditional plastic that can be recycled in your community might be the better choice.  It’s better to recycle a traditional plastic than landfill a compostable plastic.

BTW — never toss a compostable or other bio-plastic in with recyclable plastics. Even small amounts of these resins can foul an entire processing batch for your local recycler. When in doubt about which products to buy or how to recycle them, contact your local recycling coordinator.

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