Waste Wednesday

Compostable vs Biodegradable vs Recycled

Compostable vs bio-degradable vs recycled - what is the difference? Is one more environmentally friendly than the other? We are here to help this Waste Wednesday as we navigate the complicated world of disposables.

Let’s start from the beginning – what actually is plastic? Although plastic can originate from a number of different natural and organic materials, the most commonly utilised is crude oil. Once separated into its various fractions (a fraction being a group of hydrocarbon chains of similar lengths) heat is used to combine smaller hydrocarbon chains into larger ones. This can either be through the process of polycondensation or polymerisation, and by varying the process plastics with a number of different properties can be formed.

Why then does plastic get such a bad rep? Producing plastic is particularly carbon intensive, with the average 500 millilitre plastic bottle championing a total carbon footprint of 82.8 grams of carbon! But it is not just the production process which expels carbon; you may be surprised to learn that up to 29% of total carbon emissions result from the transport of raw material to their location of processing, depending on the distance and method travelled. Cleaning, filling, storing, packaging and waste generation all contribute to the carbon total.

So, where does compostable and bio-degradable packaging fit in? Although these two terms are often used interchangeably, in reality there are some significant differences between them. Both are made from plants, rather than from finite natural resources. These plants absorb carbon from the atmosphere during photosynthesis, carbon which is returned to the soil once the packaging is successfully composted. Therefore, the delicate balance of the carbon cycle is maintained. In contrast, the production of plastic releases carbon stored away within the Earth for millions of years, as well as producing more carbon during the processes outlined above, disrupting this balance as a result.

However, compostable and bio-degradable packaging have very different standards that they must meet. In reality, many different materials can be classed as bio-degradable; wood is bio-degradable if left to break down long enough. Compostable packaging, on the other hand, has to comply with the European EN13432 standard which stipulates strict criteria in terms of bio-degradation, disintegration, eco-toxicity and heavy metal contamination.

So, is there an environmental winner? The use of recycled plastic does have some clear benefits over non-recycled varieties; up to 70% of greenhouse gas emissions from plastic can be avoided through the use of recycled plastic, an amount that can be reduced further if, for example, the distance the raw material is transported is reduced.

However, there are also clear flaws in the recycling system. Only 9% of all material sent to be recycled within the UK is recycled domestically, with the other 91% sent overseas, bringing with it its own environmental concerns. There is also no guarantee of end use, both within the UK and abroad. Contamination is a big problem – many people do not realise that plastics must be thoroughly cleaned of any food waste before being placed into recycling bins, and knowledge on what items can and cannot be recycled, and which bin to place each item in, is often lacking. When these mistakes are made a whole batch of recycling can be spoilt by one contaminated or wrongly placed plastic item. Even when plastics do make it to recycling, often they can only be recycled once or twice before becoming too weak for use.

But compostable packaging is not without its flaws, one of which is, similarly to recycling, a confusion over how best to handle these items. Many people wrongly think that compostables should be recycled – however, as they are likely to include food residues, placing this packaging into recycling bins will contaminate the whole load. It is also assumed that compostable packaging can break down in home compost heaps, but compostables only break down effectively when there is the correct balance of microbes, moisture and warmth, a balance almost impossible to achieve at home. Furthermore, anaerobic digesters, such as that used at GENeco, cannot break down compostables due to the absence of both heat and oxygen. Although trials are being carried out in anaerobic digestors, currently compostable packaging is separated out during the screening process and sent to an energy-from-waste plant along with other normal packaging.

The best treatment for compostable packaging is IVC, or in-vessel composting. There are 53 IVCs across the UK which, due to the optimal conditions that they provide, are able to break down compostable packaging in under 12 weeks. How does compostable packaging find its way to these venues? Luckily, the options are fast growing. Vegware have recently launched their own bring-back scheme called Composting Collective, whereby local venues can collect compostable packaging, including that purchased elsewhere, and arrange for an organised collection by Vegware to IVC plants. Vegware have also partnered with the waste sector in many areas of the UK, including Scotland, Bristol, Gloucester and Worcester, to make the collection of compostable packaging more readily available.

However, even compostable packaging that ends up in landfill or energy-from-waste plants has some advantages over traditional plastics, as well as other commonly disposed of products. The incineration of compostable packaging produces more energy than newspaper, wood or food waste, and produces fewer toxic gases than conventional plastics. Furthermore, when it ends up in landfills, compostable packaging is inert, and therefore does not give off any methane, unlike food waste.

Although compostable packaging does have its advantages over traditional, and even recycled plastics, do not forget the commonly used mantra, reduce, reuse and recycle. By far the best way to minimise your environmental impact is to reduce the use of disposable goods, compostable or not.