Which of our bin liners wins for sustainability?
So, you have your recycling bins set up, and you're ready to get your recycling initiative up and running. Now it's time to pick your bin liner.
Biodegradable, degradable, compostable, blue or black - what's the difference?
Be wary of buzzwords
It can be marketing chaos out there with companies throwing buzzwords left, right and centre to sell you their products. In many cases, biodegradable has become the new “99% fat free,” a phrase designed to capture your attention while conveniently downplaying the other not-so-good ingredients.
In 2013 an NZ based disposable bag company received a hefty $60,000 fine for misleading customers about the eco-friendliness of their plastic products. Turns out their slogan “here today, gone tomorrow” should have been “here today, here tomorrow, here for hundreds of years to come.”
Cases like this illustrate that if you are wanting to go down the eco-liner route, you should do your homework. Lucky for you, Method is here to help you make sense of the jargon. We have put together a handy guide to to use bin liners effectively, affordably and sustainably.
The sustainability of different liners
Classic Plastic liners:
The classic plastic liner is the most commonly used bin liner, both durable and cost effective. Plastic liners are made from petroleum or natural gas, both non-renewable resources, but can take anywhere from fifteen to a thousand years to degrade.
Companies selling degradable liners seem to have ‘forgotten’ to add the bio at the front of the word, in an attempt to sell their products as environmentally friendly without falsely advertising their product.
But don’t be fooled, there is no specified timeframe that a liner sold as “degradable” must degrade. In fact, all plastics could technically be defined as degradable – they all break down eventually. Some plastics have additives that will make the liner break down faster in certain conditions, but this process only transforms large parts of plastic in tiny sized pieces.
Professor Tony Underwood from the University of Sydney described degradable plastic bags as "not a solution to anything much, unless we are quite happy to shift it all into particle-sized plastics rather than plastic bag-sized plastic."
Micro-plastics are hard to contain in landfill and have recently been under scrutiny for their harsh impact on marine life. They are ingested by microorganisms and make their way up the food chain, ending up in animals and even humans.
Plant Based plastics:
Some people opt for plant based plastic liners as an environmentally friendly alternative to the classic plastic. As the name suggests, these liners replace non-renewable petroleum with biomass like sugarcane and corn, in a bid to reduce harm to the environment.
Plant based plastics can be broken down further into two categories – non-biodegradable and biodegradable.
Non-biodegradable plant-based plastics are produced in the same fashion as, and are intended to replicate, normal plastics. Plants are manipulated to give the plastic long shelf life and final product cannot be easily digested by living organisms. This makes them fit for the recycle bin but not for the compost.
Biodegradable plant-based plastics (the most common variety of biodegradable liners) are called so because they can be attacked and digested by living organisms in the early stages of the degradation process. This means that they complete the natural cycle – they are produced and assimilate smoothly back into nature.
Certification standards have been created to ensure that what we are buying is going to fully biodegrade within a specific timeframe. When looking to buy biodegradable liners it is very important that the product refers to a reliable standard such as AS 4736 or EN 13432.
Biodegradable liners can be broken down even further into two categories - commercially compostable and home compostable.
Commercially compostable liners
Many biodegradable liners require a very specific environment to decompose – oxygen, 60 degree temperatures and a perfect heat/moisture ratio found at a commercial composting site to be exact. These are called commercially compostable liners and should only be used if your waste is going to a commercial composting site. If you’re putting commercially compostable liners into landfill, then either a petroleum or a biodegradable liner would realistically be just as suitable and sustainable.
Home compostable liners
Home compostable liners can be broken down in with all the wormy goodness in your backyard compost bin. These are your most environmentally friendly option. You’ll need to check the liners refer to a certification standard okay for home compost though, such as AS 5810-2010.
So then we should use these liners for all waste streams, right? Well, not exactly. Landfills are very dark, non-oxygenated places, meaning that even compostable liners do not have the conditions needed to biodegrade properly. Over time, compostables in landfill produce methane which can be much more harmful to the environment than CO2 itself.
So what does this all mean?
The most sustainable way to use bin liners would be to use the home compostable variety, BUT to then remove the contents into the bin before waste collection and put your liner in with your home compost. But this isn’t always possible.
Start a conversation with your waste collection providers about what their bin liner policy is
If you wish to keep your waste continuously contained, or it’s not viable for you to go liner-less because of your waste collection provider, WeCompost - an Auckland eco waste removal company dedicated to treating compost as a valuable resource - recommends using black liners for landfill, clear liners for recycling streams and home-compostable liners for organics.
This makes it easy for office cleaners and collectors to sort and ensures that compostable liners are not going into landfill, where they’ll most likely struggle to degrade in the conditions or just be ripped open.
You can also consider options for plant based, non-biodegradable liners - while they are still plastic, at least they are made from a renewable resource and are much less toxic in their production.
WeCompost actually prefers that recyclables are left loose within the wheelie bin for pick-up so that items can be mechanically sorted. They’re happy to collect rubbish and organics without the liners, meaning you can use plastic, or home-compostable liners in your indoor waste streams, empty them into the wheelie bins for collection and then re-use or compost them.
Finding the right bin liner doesn’t need to be complicated
If you do your research, make sure bin liner buzzwords are backed up by reliable certification standards, and discuss options with your waste removal contractors and cleaners, you’ll be well on track towards your sustainability goals.