Types of Plastics
The world of plastics can be confusing with a multitude of different symbols, names and methods of disposal. It could be easy to think that bioplastics, biodegradable and compostable are all interchangeable! However, there are some key differences which determine how best to dispose of them and whether you should use them over conventional plastic at all. For more information see WRAP.
First and foremost, it is best to avoid and refuse all plastics where possible, but we look at the facts of the different types below.
Bioplastic is made from marine or plant-based materials (such as corn and sugarcane) instead of petroleum and, therefore, is considered more environmentally-friendly than regular plastic.
This is because their production requires less usage of fossil fuels and generates less greenhouse gases than that of petroleum-based plastics. Some bioplastics are also made from waste agriculture by-products, such as potato peelings, which promotes material recycling.
While more sustainable than conventional plastic, the environmental impacts to consider include:
- Potential chemicals released when it breaks down
- Growing crops to make bioplastics = intensive agriculture, including greenhouse emissions from the petrol needed to fuel farm machinery.
- Water pollution caused by runoff from land where fertilizers are used in industrial quantities.
- Pollution and fuel used from worldwide transport.
In some cases, these indirect impacts from bioplastics are worse than making normal plastics in the first place, but they come from a more sustainable source.
If it’s put into food waste collections it gets removed at the beginning of the Anaerobic Digestion process and sent to Energy From Waste as there’s no way of knowing whether it’s bioplastic or normal plastic.
As the name suggests, biodegradable plastics contain additives that cause them to decay more rapidly in the presence of light and oxygen (moisture and heat help too)
Plastics that are labelled “biodegradable” typically can’t be composted, but can be broken down by microorganisms – though the exact method and timescale for this process varies.
A recent study found that biodegradable carrier bags could still hold shopping after having been buried in soil or left in the sea for three years.
Unlike bioplastics, as biodegradable plastics are made from normal plastic petrochemicals, they don’t always break down into harmless substances: sometimes they leave behind a toxic residue and plastic fragments that are harmful to the environment. So reusing a normal shopping bag multiple times and then disposing of it correctly may be better for the environment than using a biodegradable bag once.
Double check that any items you buy/use that are lined or made with compostable PLA (polylactic acid) meet European EU directive 13432 and has the official compostable symbol. This means the packaging has to break down within 12 weeks to water, CO2 and biomass, leaving no more than 10% of the original material in pieces bigger than 2 mm.
Compostable materials such as takeaway cutlery in Devon can only be composted in your home/allotment. It won’t break down in landfill and if put in recycling can contaminate large batches. It can’t be processed in the food waste collection (as we can’t tell what’s normal plastic and what’s compostable) and it also will not be accepted in garden waste collection – it breaks down at a different rate to regular garden waste and therefore would contaminate batches. See here for more info. If you’re buying things like compostable cups and plates for your business or event, it is your responsibility to ensure they are disposed of correctly so do the research (see WRAP guidelines) and advise your customers – likewise if you receive a compostable cup at an event don’t automatically assume it can go in your compost bin! Please try to dispose of the plastic correctly, but even if it’s sent to landfill, it can still be better than normal plastic as it uses less non-renewable materials.
Only if the compostable plastic carrys the “OK Compost” symbol on the right does it mean that it’s certifiable able to compost at home. This is granted by an independent organisation which conducts controlled tests on packaging. Compostable plastic producers may have run their own tests so may also state that you can compost them at home.
If they are discarded in the environment, research has shown that compostable bags can survive for two years in soil. In seawater they could disappear in as little as three months, although exactly what products they release into the marine environment is not yet clear. A good option if you have your own successful compost bin at home, but please don’t put them in food or garden waste collection.
Food Waste Caddies
Please see your local district website for their official stance on what to use. Devon County Council recommends that councils allow residents to line their food waste caddies with, in order of what’s best,
- newspaper/waste paper,
- any leftover plastic bags (such as bread bags, shopping bags, produce bags, large multipack bags etc)
This is due to the fact that any material which is not food waste gets removed from the system and sent to the Energy From Waste plant. There is no way to tell whether the material the bin is lined with is biodegradable or normal plastic, and even if it is biodegradable, it doesn’t break down within the anaerobic digestion process. On top of this, bio/compostable plastic alternatives become very stringy and clog up the digester and system, causing extra expense for it to be cleaned out more regularly.
Stretchy plastic packaging i.e. Bread bags
You may be able to take plastics not accepted in your collection, such as plastic bags, clingfilm and yogurt pots, to your local Household Waste Recycling Centre. Instead of sandwich bags, use beeswax wraps instead – try our easy recipe!
The majority of conventional black plastic packaging is coloured using carbon black pigments which cannot be sorted using Near Infra-Red (NIR) technology, which is widely used in plastic recycling. Therefore black plastic packaging commonly ends up as residue and sent to Energy From Waste. It can be taken to Household Waste Recycling Centres too. We need packaging manufacturers to stop using black plastic and for consumers to try not to buy it.
Bamboo Cups and Cutlery
You may be fooled into thinking that anything with bamboo in it is better for the environment – especially when it’s got labels like eco-friendly on it. However, some bamboo based products may still contain almost the same amount of plastic as their counterparts! The plastic is mixed with bamboo fibres to create a hybrid material which can also contain some toxic chemicals, harmful to both you and the planet. Please check that the brand you are buying is definitely sustainably sourced and toxin free, or choose an alternative material like metal.
Other Packaging Materials
Recycling symbols appear on lots of everyday items and help us to identify how different types of packaging can be recycled.