Degradable, Biodegradable, Compostable?
It is very likely a fair proportion of the waste at your event will be made up of material that could be composted and turned into life giving fertiliser.
One festival I worked on, 13 tonne of compostable waste was collected representing 80% of the total waste generated in the arena. It was mainly food packaging but unfortunately, also, lots of food.
The challenge is, being aware of the differences in compostable and biodegradable, degradable, and bioplastics.
You will see materials that use the these terms and it is important to know what each means. The composition of materials have a significant impact on resource recovery processes you align with, as does your chosen onsite segregation process. For example, being biodegradable does not necessarily mean that it is compostable.
Generally (natural) resources which breakdown under natural processes, but are harmful to the environment, come under this category.
So which is it?
There is often a lot of confusion and mis-information around ‘compostable’ materials, particularly food and beverage service-ware for events.
- Oxo- or photo-degradable
Have a listen to Lucinda from Going Green Solutions talk us through compostable, biodegradable and degradable. If you’re in Australia, you can purchase compostable products from Going Green Solutions.
Degradable means the material will disintegrate into small pieces of the same material in the presence of sunlight/oxygen. This is NOT something you want to aim for. Plastic that is ‘degradable’ such as you may have seen for shopping bags, has been treated with more chemicals which make it disintegrate quicker. This accelerated disintegration just makes it into micro or nano plastics faster – not something want, clearly!
Biodegradable means the material will be consumed by micro-organisms, under natural conditions, over the course of time. Think of a tree falling naturally in a forest, and nature eventually consuming it. For some items that are definitely going to be lost as litter, this is at least a way to go.
Compostable means the material will biodegrade in one industrial compost cycle. Sugar cane fibre, areca palm plates, paper/cardboard plates and cups not coated with plastic are good examples.
How to distinguish what is what?
Claims of ‘compostable’ and ‘biodegradable’ are regulated by standards such as the US Standard ASTM D6400, European Standard EN13432 and Australian Standard AS4736-2006.
For more information on biodegradable products, visit the Biodegradable Products Institute website (bpiworld.org) and their terrific site findacomposter.com for the US and Canada.
Quick tip: Don’t take the label or the manufacturer’s claims as true. If you are purchasing items you intend to send for composting, ensure they meet the standards for compostable material in your country. If there is no such standard, check the intended composting facility or process you plan to use can actually successfully compost the materials..
Keep it out of landfill!
Waste suitable for decomposing under biological conditions should be kept out of landfill. This waste will be anything made from plant or animal material. For events this includes food waste, certain disposable food and beverage packaging, paper, and possibly cardboard. Some fabrics are also suitable for composting if they are not dyed or bleached (e.g. maybe hemp, cotton, hessian, jute).
These materials, deep down in a landfill, will potentially decompose in the absence of oxygen the landfill, and create methane. Methane is a greenhouse gas and it’s many more times as potent a greenhouse gas than carbon dioxide. Processing options for this waste stream are com- posting or anaerobic digestion (AD). If you have a lot of green waste it could also be mulched, which will eventually naturally break down when used on garden beds. Methane harvesting from landfill sites is also an option.
The main consideration in planning for this waste stream from your event is whether decide if it will end up in a landfill site to create greenhouse gas emissions, be converted into biogas for electricity generation, or be turned into life-giving compost.
Cornstarch material which is clear and looks like plastic (PLA) may fit into this category, though for various reasons, we don’t recommend this product in many event scenarios.
Bioplastics are products that perform as plastics (e.g. bottles, cups, packaging) but are made from renewable plant-based resources, rather than the fossil fuels that conventional plastic is made from. Not all bioplastics are biodegradable. Bioplastics are either starch based or cellulose based. Often bioplastics are called nature-based plastics.
Using bioplastics is beneficial as compared with oil-based plastics it is not using this non-renewable resource. Depending on production processes, Bioplastics may have smaller carbon footprints than their plastic counterparts.
Polylactic Acid (PLA)
This cornstarch-based material is used to make products that resemble oil-based plastics. In the event industry this will appear most often as beverage cups or clear salad containers with lids. PLA cutlery and coffee cup lids are also available.
Genetically modified corn is often used in the manufacture of PLA. This is a moral challenge for some and could be a reason not to use it.
Some PLA suppliers promoted their products as being compostable; however, this is only possible in some commercial composting facilities. PLA will not degrade readily in landfill.
At this point most bioplastics, PLA included, will need to be sent to landfill or for incineration.
The following questions will help you confirm if including Compost Waste is a viable Zero Waste strategy for your event:
- Identify whether food waste collection for separate treatment (eg composting or anaerobic digestion) is possible. Is there a service locally?
- Identify whether onsite at-event segregation of food waste can occur from a practical perspective. Will attendees participate?
- Can food service or waste operations adjust to collect the food waste separately?
- Put ‘binfrastructure’ and systems in place to collect food waste both in kitchens, back of house and attendee side (front of house)
- Ensure systems are effective – consider placement of bins, appropriate signage etc
- If disposable food serviceware must be used, use compostable
- Collect food waste and compostable food serviceware for composting
- Ensure bin signage accurately communicates what food and serviceware can be composted