When it comes to the environment, plastic gets a raw deal – often being blamed for using up our petrochemical oil stores, filling up our landfills and poisoning our soils.

In fact, I asked 25 people in our office what they thought the number one item of concern in landfill was, and the majority said plastic. Not a scientific study I know, but it seems it is viewed as a huge problem. So, I thought it was time to look at the facts and figures of plastic production and its impact on our planet.

How much of the world’s petrochemical oil is used to make plastic?
Estimates generally state that about 4% of the world’s annual oil production is used as the raw materials for plastic, and another 4% provides the energy for production, so not all the oil we use is locked up in the plastic itself.

How much oil does it take to make one kilo of plastic?
If you look at HDPE (high density polyethylene), which is an easily recyclable plastic we use in our product packaging, it takes around one and three-quarter litres of oil (including both the raw materials and the energy) to make one kilo of plastic.

What methods are used to dispose of plastic?
Again, let’s look at HDPE. If you bury it in landfill, it’s not going anywhere soon. Current estimates for any plastic decomposition rates vary from 20 years up to 600 years (source: ctenvironment.org), but the simple truth is that plastic hasn’t been around long enough for us to know for certain.

If we incinerate one kilo of HDPE to generate energy, only water and carbon dioxide are produced, but the heating value is equivalent to only three-quarters of a kilo of oil, so in effect, we have lost one kilo forever (remember it took one and three quarter litres of oil to make!) By recycling fossil fuel plastics, we can save roughly four and a half litres of oil for every one and a half kilos recycled, which is a significant saving.

What about plastics that don’t use petrochemical based oil?
Plastics produced from corn may appear to be the perfect solution – they look, feel and behave in a very similar way to ‘traditional’ plastics – but there are questions about the benefits they may have on the environment.

Firstly, there are concerns about genetically modified ingredients (GM), as corn grown for plastic production is likely to be genetically modified, and if you read July’s Letter from Liz you can appreciate the issues this may raise. Growing corn is also an energy intensive task, both in the actual growing (pesticides and fertilisers consume a massive amount of fossil fuels in their production) and the harvesting, processing and transportation, which will almost certainly be powered by fossil fuel oil. As I said earlier, only 50% of the oil used when making plastic is in the raw materials, so the issue of sustainability isn’t completely solved. Growing food crops as monocultures on vast areas of land to produce plastics also throws up some interesting ethical questions. For example, could we be feeding people on this land? And what effect does this have on biodiversity?

What about biodegradable plastic?
Again, this seems like the perfect solution to the waste problem – a plastic container that dissolves harmlessly into the ground – but looking at it in more detail throws up more issues: the disposal of biodegradable plastics causes potential problems with recycling, as it is indistinguishable from traditional plastics, and when mixed in with them can render the whole lot unsuitable for the recycling process. Fundamentally, biodegradable plastic is not recyclable.

Could it also be the case that producing ‘degradable’ plastics sends the wrong message about waste? If the world believes that anything we throw away will disappear without any environmental penalties at all, where is the incentive to improve or reduce what we throw away? A biodegradable plastic bottle is produced using energy and all this investment in energy is lost when it is simply thrown away.

So what is the answer?
Re-using plastic bottles would ensure all the energy used in its production was recovered, but in reality, the re-use of plastic bottles for food or cosmetics would raise issues with hygiene and contamination. You can’t sterilize a plastic bottle very well as it can’t take the heat.

Recycling plastic bottles to produce more bottles (recycling) or recycling bottles to produce items such as drain pipes or car bumpers (downcycling) ensures that at least we retain the value of the raw materials plus a larger proportion of the initial energy investment than if it was thrown away.

Finding the best solution is complex and full of questions, but I believe one answer lies in improving and refining our recycling systems to collect and recycle more plastics. There is certainly a market for it, and bearing in mind the UK alone uses around 275 thousand tonnes of plastic each year (source: recycling-guide.org), there’s an awful lot of energy worth saving.

Finally, with regards to ‘Reduce, Re-use, Recycle’, we should always be looking at reducing the plastics we use. Ian Curtis, our Technical Packaging Manager here at Liz Earle, constantly balances product protection and safety with the need to find ways of reducing the amount of plastic in our packaging.


What is compost, and why is it a good thing?

Compost is plant matter broken down by the action of bacteria, fungi and minibeasts like worms and millipedes. Around 30% of the average household bin’s content is compostable waste. If this waste is properly composted it will break down into a crumbly, nutrient rich material which can be used on any garden. Compostable waste that ends up on landfill tends to rot, often without oxygen, and so produces methane (a potent greenhouse gas). It also means that 30% of our valuable landfill space could be put to better use.

Many local authorities provide collection facilities for food waste, and separation for garden waste at landfill sites which is then composted on a grand scale producing a commercial compost.

If you don’t have this facility – or, like me, you think that your compostable waste is too valuable to throw away, home composting is an easy alternative.

So what do you need to make compost?

Carbon – from woody plants, stems and corrugated cardboard
Nitrogen – from soft fleshy plants, grass cuttings, hair from your pets (or human hair from home hair cuts!), vegetable peelings and fruit cores.
Oxygen – compost needs stirring once a week to add air to the pile.
Water – to keep the bacteria functioning. Some creatures, such as millipedes, only thrive in moist environments so a compost heap needs to be damp but not waterlogged.

You can compost without any special equipment at all – that’s the classic compost ‘heap’. This will work fine but your compost heap will need turning regularly and covering to prevent rainwater washing the nutrients out and also to keep the heat generated by the microbes in.

If your compost is slimy and smelly it needs oxygen and carbon, and is probably too wet, so give it a stir with a garden fork and add some brown stuff like cardboard or shredded twigs.

If your compost is dry, and nothing seems to be happening, you need to add nitrogen and moisture. Usually, adding soft green material like grass cuttings will reset the balance. You can give the pile a very light watering as well – just make sure you don’t overdo it! And stir well…

Here at The Green House we compost all our food waste; tea bags, coffee grounds and orange peels all go in. We use a special hot composter  which will break down waste, cooked food and scraps from staff lunches that would not normally be safe for composting.  It all goes towards reducing the waste we send to landfill.

I  have two 300 litre bins at home – a little excessive perhaps, but I am a compost fanatic – and it enables me to keep one bin filled up while I use the compost from the other bin. I put virtually all the cardboard I receive as packaging in there, as it mixes really well with grass cuttings. Last year, with very little effort, I produced 300 litres of compost to plant my seedlings in – and all for free!

We would love to know about your composting tips and ideas, please add your comments below: