It's time to choose between recycling and redesigning materials

Written by: Michael Stephen | Published:
Michael Stephen

We all agree that we should recycle materials to reduce consumption of new resources and reduce the burden on landfill sites. But recycling also has to be cost-effective in economic and environmental terms.

Plastic is the best material for protecting food and other goods from contamination and damage, and is much better than paper, cardboard or cloth – especially when wet.

It is obvious that no material can be recycled unless it can be collected, but in the case of plastics, far too much of it gets into the open environment as litter from which it cannot realistically be collected. This plastic degrades quite quickly into fragments, but it does not become biodegradable for very many decades.

Governments can continue to ban or tax plastics but that will not solve the problem in the foreseeable future, even in the Western world, and will have undesirable consequences.

The scientists who developed plastics designed them to be durable, but they realised in the 1970s that this very durability would cause a problem if the plastic gets into the open environment as litter.

They therefore looked for ways to make the molecular structure of the plastic dismantle automatically when it had served its purpose, eventually leading to the creation of oxo-biodegradable (oxo-bio) plastic.

It is important to understand that this does not just create fragments of plastic – instead the plastic converts itself into biodegradable materials. The process, is described by Professor Ignacy Jakubowicz of Sweden, as follows: “The degradation process is not only a fragmentation, but is an entire change of the material from a high molecular weight polymer, to monomeric and oligomeric fragments, and from hydrocarbon molecules to oxygen-containing molecules which can be bioassimilated.”

The only environmental conditions necessary for oxo-biodegradation are oxygen and bacteria, both of which are found everywhere in the open environment. (Bio-degradation in landfill is not necessary, and would generate methane).

Oxo-bio plastic products are not designed to degrade instantly as they need to have a useful life. They should be used in the same way as ordinary plastic, but when they have served their purpose they drastically reduce their dwell-time in the environment.

A life-cycle assessment (LCA) by Intertek in May 2012 found that oxo-biodegradable plastic had the best LCA of all materials used for making carrier bag and bread bags.

The process

Oxo-bio plastic products are made from ordinary polymers, but the manufacturer of the product adds a catalyst to the polymer mix which accelerates a change in the molecular structure. Oxo-bio plastic can therefore be made by existing plastics factories at little or no extra cost, with no need to change their machinery or workforce. The resulting products look, feel and behave like conventional plastic during their useful life, and are just as strong, waterproof, lightweight and flexible.

With regard to resources, polyethylene is made from ethylene, which is a by-product of refining oil for petrol, diesel and aviation fuel, so the oil would be extracted from the ground in a similar amount even if plastic did not exist. It makes sense to use this by-product instead of using scarce land and water resources to make bio-based plastic - which cannot be recycled, and is tested to biodegrade only if taken to a composting facility.

Where plastic products are particularly lightweight and contaminated with other materials, the energy and resources used in collecting, transporting, sorting, cleaning, baling and reprocessing are more than those required for producing new plastics, and such cases recycling is not the most economic or environmentally sound option. Instead of being recycled, these plastics are being dumped in the forests.

Yet the pressure to recycle these materials, whether it makes sense or not, may come into conflict with the need described above for biodegradability to protect the environment from long-term pollution by plastics.

It is said that oxo-bio plastic packaging cannot be detected by current technology at sufficient scale to be sorted out from conventional plastics, but this is easily remedied by requiring the inclusion of a tracer in the oxo-bio plastic at manufacturing level when the equipment can recognise.

However, some research in Austria and South Africa found this was not necessary because oxo-bio plastic can be safely recycled without separation.

In the last four years, enough masterbatch, (which contains the pro-degradant catalyst) has been sold by one OPA member alone to make 600,000 tonnes of oxo-bio plastic products. We know that those products have been successfully recycled for the past 15 years around the world, and in those 15 years we have heard no reports of any difficulty encountered.

The problem is that if we continue to use ordinary plastic, thousands of tonnes of it continue to escape into the environment every year. This will undoubtedly create microplastics and will pollute the environment for many decades into the future. Dealing with this problem is the most important issue of the day - not recovering low-value plastic materials by mechanical recycling.

There are several countries in Asia, Africa and the Middle East where governments have taken a pragmatic approach to the problem of plastic litter and legislated to make oxo-bio plastic mandatory for a wide range of everyday products. The rest of the world has been slow to act.

We are at the point where we have to choose – are we going to continue to use plastic that can lie or float around for decades, or a plastic that can be bioassimilated and recycled back into nature in 2-3 years or less? Of course we don’t want plastic in the open environment at all, but that is not the present reality.

Michael Stephen is chairman of the Oxo-biodegradable Plastics Association

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