An Explanation of Plastic Recycling by Dr Peter Cox

An Introduction to Plastics Recycling by Dr Peter Cox

Dr Peter Cox is a chartered mechanical engineer who first started working with plastics in the 1970s. He has been associated with polymers (both plastics and rubbers) ever since and is now a consultant and chairman of the Plastics Consultancy Network. During his time at the Metal Box R&D centre in Wantage he helped develop a multilayer plastic jar which used one sixth of the energy of a glass jar to manufacture and distribute. He was also involved in early European projects on recycling, working on ways to differentiate different plastics.

There are over 50 unitary authority councils in England and nearly all them have a different policy as to what is collected in the green bins – as they are coloured in West Berkshire (other areas have blue, brown and no doubt every colour of the rainbow). As a person involved in plastics for over 40 years who started on recycling over 30 years ago with Metal Box R&D at Wantage, I am often asked as to why should there be so many different policies and why does West Berkshire Council only collect bottle-shaped plastic?

What do Plastics and Recycling Mean?

Let’s start at the beginning and try and define what we mean by “plastics” and “recycling”. To take the true definition of plastics, they surround our every day life from the lining inside your fridge, a good percentage of the car you drive, the clothes you wear, the cellophane that covers the flowers you buy, the bottle you get your milk in and the numerous forms of protective plastics that surround the food you buy.

Recycling has different definitions:

a) recovering the original chemicals that make up the plastic
b) cleaning and reusing the product as it is
c) reusing the plastic in another form such as garden furniture
d) incinerating the plastic to recover the exceedingly high energy stored in the product.


Why is this topic so important? Well, thanks to David Attenborough and his Blue Planet TV programmes, the sight of the oceans covered in floating plastic waste and the harm to creatures which live in the sea, or use it for food, our consciences have been rattled and there is a cry to “Ban Plastics.” However plastic are not all bad. As mentionned above, they weigh a lot less than glass and therefore use a lot less energy to transport (take milk bottles for example). But disposal of plastics is a big issue, because of the extent to which they have contaminated the environment.

The Problem About National/EU Targets

There is a governmental target to be achieved setting the amount of waste that is/should be recycled. I do say government but it is in fact an EU target which has been set at 50% of all household waste to be recycled by 2020 (The figure for the UK in 2017 was 45.7% but it does vary for Scotland, England and Wales). 

What does this mean? It actually relates to the total amount of waste collected that does not go to landfill. So, your green bin full of grass cuttings is counted as being recycled. Because of the much higher density, one bin full of cuttings will be equivalent to over 4 green bins of compacted (in other words totally squashed) plastic waste. 

No wonder Veolia would rather collect the grass. 

The weight effect is highlighted in the graph below taken from a DEFRA report from 14 February 2019 which shows the relative tonnages of waste collected in 2016.


In terms of collection, grass wins easily over plastic in terms of weight so there is no motivation to increase the amount of plastic that is recycled when collecting grass is a much easier way for authorities to meet their targets.

Is Biodegradable/Biobased Plastic the Solution?

This sounds promising but all is not straightforward here as really there are two types of biodegradable plastics:

1. those that will naturally degrade in soil

2. those that need very specific conditions such as an elevated temperature in the absence of air.

And biobased plastics again have two different definitions:

1. where the chemicals required to make the plastic are derived from naturally grown products (one of these is the Brazilian Braskem process that converts sugarcane to ethanol and then to polyethylene which could be used in plastic films). However, these products are confusingly not biodegradable!

2. where chemicals are used which will eventually biodegrade (a useful example here is associated with medicine where temporary use inside the body of such a plastic will end up being dissolved and avoid further surgery).

It is clear that there are almost as many types of plastic as there are types of trees. And even splitting it down to packaging there is still a very wide variety.

West Berkshire Council’s Plastic Recycling Policy

Here I disagree with WBC’s very selective policy of only collecting plastic bottles which are predominantly made from High Density Polyethylene (HDPE) and PET with still a few made from flexible PVC.

They have the distinctive property which is THEY CAN BE SOLD whilst it is not possible for other forms of plastic waste products! I have been reliably informed that this is the reason why WBC only collect bottles.

The reality in West Berkshire, however, is that many residents put many different kinds of plastic in their green bins, not just bottle-shaped plastic as requested by Veolia. And we have evidence that Veolia might actually be sending this non-bottle shaped plastic to their facilities in Hampshire that burn waste to make energy (because there are no landfills in Hampshire):

Questions and Answers Executive Thursday, 20th December, 2018

Question submitted to the Portfolio Holder for Planning, Housing and Waste by Ms Carolyne Culver:
“What happens to the contents of the green recycling bag if it is contaminated with plastics that cannot be recycled – e.g. bottle tops, margarine tubs etc?”

The Portfolio Holder for Planning, Housing and Waste answered:
… Contamination from non-bottle plastics such as most tubs and trays, bottle tops, hard plastics such as plant pots or toys, cling film and polystyrene are removed during the process at Padworth and sent to an energy from waste facility for disposal..

We will be asking Veolia to comment on why they don’t officially admit to processing all plastics collected from West Berkshire residents. It is time for WBC to wake up and put pressure on Veolia (who has a longterm 25 year contract with WBC) to officially collect ALL plastics from West Berkshire to keep them out of landfill.

The Benefits of a National Policy on Recycling

It is clear that recycling policies vary hugely from authority to authority. Our neighbours in Oxfordshire collect all forms of plastic and thanks to their contact with Viridor they have diverted 95% of their residual municipal waste away from landfill to the Adrley ERF (Energy Recovery Facility) site near Bicester which generates power for around 53,000 homes. The energy of course is sold and it is a win-win situation.

Many people believe that a national policy on recycling will be much more efficient and make it easier for manufacturers to label their packaging to help consumers know how to recycle them.

To help acheive this goal, DEFRA are conducting a Consultation on Consistency in Household and Business Recycling Collections in England. Please have your say by 13 May.

DEFRA’s statement behind the consulation:

The Government supports comprehensive and frequent rubbish and recycling collections. We have seen household recycling rates in England increase significantly from 11% in 2001 to 45.2% in 2017.  However, in recent years, progress has been slower and rates have remained at around 44/45%.  While many local authorities continue to make improvements and introduce new services, some have seen a drop in recycling rates and do not collect the full range of materials that can be recycled or do not collect food waste separately. Householders who want to recycle more are increasingly confused about what can be recycled.

Plastic waste is one of the world’s most urgent environmental problems. Public awareness of plastics as an environmental concern has risen in recent years, and there’s a large demand for better waste managment including better recycling.  Apart from Landfill Tax, which has incentivised diversion from landfill disposal and historically helped to increase recycling rates, there are very few current drivers to encourage local authorities to expand recycling services or for businesses to invest in recycling services. This makes it harder to improve the quantity and quality of what we recycle.

China’s ban in 2018 on the import of post-consumer contaminated plastic and paper has also added to the need to improve the quality of what is collected for recycling and to reduce contamination. Contamination arises from people putting items in their recycling bin that are not collected locally for recycling or materials which are not collected as part of dry recycling, such as nappies or food waste. Improving the quality of material collected would help to increase demand for these materials in the UK and help to ensure that they meet higher quality standards for export.

Members of the public, industry and other stakeholders have called for greater consistency in the materials collected for recycling as well as, to some extent, how it is collected. There have also been calls for investment in separate food waste collection to reduce the amount of food waste going to landfill, where it releases harmful greenhouse gases.


2 Responses

  1. A very educative excercise/guidelines you have detailed relating to “recycling” of plastics.This could form a chapter in the curriculum of science students both in schools n colleges,as an exercise in “awareness” relating to the benefits of plastics as group of materials n the concept of disposal /treatment through recycling/incineration, as important options to the society at large. I HAVE ALSO BEEN INVOLVED/associated with plastics applications ,environment/waste managemnt/recycling for the past fifty years.My compliments to the author…O P Ratra 29 Sept
    2020, India

  2. I can see from my own uni learning that the content above is relevant. Would ask? have you published a paper or journal on this matter and can I access it?

    I am just setting up my own website and whilst I admire your site I am not sure I can afford the on costs for now) so I intend to go down the charity route, when relevant.

    Would be good if you could comment on my site)

    having issues still after 14 days with a outage between bt and yahoo. could not have happened at a worse time:/ when creating site. hope by the time you reply it will be sorted. Uni student, 66 years old) young)

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