Biodegradation & Composting

Compostable Plastic Film Not so Sustainable

Ever wondered why your print copy of Physics World is still delivered wrapped in plastic?

That’s about to change, but as Susan Curtis finds out, abandoning single-use-plastic magazine wrappers is not as straightforward as it sounds

Who can forget the Blue Planet II documentary broadcast by the BBC in 2017?

It showed a turtle tangled in plastic netting, while albatross chicks in South Georgia could be seen ingesting large and potentially deadly pieces of plastic litter.

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Graphic evidence, if any was needed, of the damaging impact of plastics pollution – it was the TV show that underlined why we have to kick our plastics habit.

That year also saw a landmark study by US academics, which revealed that 8.3 billion tonnes of plastic had been produced since the 1950s.

Almost 80% ended up in landfill or the natural environment, where it is set to last for hundreds or thousands of years (Sci. Adv. 3 e1700782).

The UK alone generates around 2.4 million tonnes of plastic packaging each year, barely a quarter of which gets collected for recycling.

What’s worse, up to 27,000 tonnes of plastic waste washes into the UK’s seas and oceans each year (2015 Science 347 768).

So why, when your print copy of Physics World magazine lands on your doormat, is it still wrapped in polythene?

Like me, you probably rip the wrapper off and bin it, adding to the mountain of single-use plastic destined for landfill where it will persist for decades, possibly even releasing methane when it finally degrades.

Surely there’s a better option for the planet, particularly when other magazines arrive in compostable wrappers or good old-fashioned paper?

Come on Physics World, sort it out!

Trouble is, even well-intentioned decisions can have undesirable outcomes.

Millions of people were once persuaded to buy diesel cars on account of their low carbon emissions – only to find out later, as I did, that their supposedly eco-friendly vehicle spews particulates that endanger human health.

In a similar vein, plastic carrier bags have a lower overall environmental impact than paper bags or fully reusable cotton totes, according to a full “life-cycle” analysis carried out by the Danish Environmental Protection Agency in 2018.

“When we make decisions about materials, including what to use for bags, we have to consider all the environmental impacts,” says Sophie Hadden of WRAP UK, a not-for-profit organization that offers guidance on sustainable packaging.

“It is never straightforward and there are always trade-offs.”

Relevant factors include the amount of greenhouse gases emitted in producing the bag, whether the material is derived from renewable sources or fossil fuels, and if it can be recycled and incorporated into new packaging.

With many Physics World readers having written in to ask why it’s still encased in plastic, I’ve been exploring what exactly is the most eco-friendly magazine wrapper.

Given the resources available to me, I couldn’t do a proper life-cycle analysis, so I chose three criteria to investigate.

First, can the wrapper be reused or recycled? Second, what are the material and energy costs of producing and disposing it?

And third, what are the practical pros and cons of the different options when it comes to sending thousands of copies of Physics World to readers all around the world?

Polymer problems

Let’s start with the current plastic wrapper, known in the publishing trade as “polywrap”.

It is made from low-density polyethylene (LDPE) – the same material that’s used for supermarket carrier bags.

Consisting of repeated units of ethylene (C2H2)n, LDPE is so ubiquitous because it is cheap to make, adds little weight to a package, and is strong enough to withstand wind, rain and rough handling.

Polywrap is also transparent, which is vital to enable postal services to scan any barcodes printed inside and to let readers see what’s been delivered.

Best of all, it can be recycled, and the polywrap used for Physics World is made from 100% recycled material, according to our supplier.

These factors might surprise you, given the perception that LDPE is hard to recycle and can only be reprocessed into low-grade products such as refuse sacks.

But some reprocessing facilities can grind waste LDPE into pellets that can then be used for new plastic products.

What’s more, several companies are examining promising new ways to recycle plastic wrappers (see box “New solutions to recycling plastic film”).

WRAP UK sug­gests that recycling a single tonne of plastic film, rather than creating virgin polymer, could prevent 0.83 tonnes of carbon dioxide from being released into the atmosphere.

So far so good. But polywrap’s environmental credentials are far from perfect.

The ethylene units in LDPE are obtained by cracking fossil fuels.

The ethylene produced in this process is then piped into a processing plant where it is polymerized at pressures of about 300 MPa.

According to the trade body Plastics Europe, this consumes about 77 GJ per tonne of plastic product, around two-thirds of which is needed to extract the raw ethylene.

Another problem is that very few local authorities (in the UK at least) collect any type of plastic film for recycling.

Strong but flyaway, it gets easily tangled in the machines that sort and separate curbside collections.

Around 4500 supermarkets across the UK do provide storefront collection points for carrier bags and anything else made from LDPE, but who bothers with that?

And while some supermarkets’ home-delivery services take plastic bags and film back for recycling, coverage is patchy and working out which stores offer the service isn’t simple, even with the help of websites like Recycle Now.

More worrying still is that few people are aware that polywrap can be recycled at all. Some labelling schemes provide clear information to consumers, but fragmented and conflicting waste-management regimes make it hard for householders to know which plastics can be reprocessed in their area.

According to WRAP UK, less than 5% of LDPE products are currently recycled in the UK, despite almost 400,000 tonnes of the stuff having been released into UK consumer markets in 2017.

Starchy option

So if polywrap is bad, what are the alternatives?

In a high-profile move in 2018, the National Trust (a charity that manages places of historic interest or natural beauty in England, Wales and Northern Ireland) switched all 2.4 million copies of its membership magazine to a compostable wrapper containing up to 30% of potato starch, a waste product created when potatoes are made into crisps and other foodstuffs.

Starch is composed of long-chain polysaccharide molecules (C6H10O5)n that come in both linear and branched varieties.

“The imperative for the trust was to eliminate single-use plastic as soon as possible,” says Graham Prichard, the organization’s former print manager who is now an independent publishing consultant.

“We had already started to investigate various alternatives to plastic, but the starch wrap fitted the brief and was readily available from our mailing house.

The executive board made an extraordinarily quick decision to make the switch.”

The wrapper used by the National Trust is called Bioplast 300, which is made by Alfaplas in Hereford, UK.

“Bioplast 300 has been certified to European standards as fully compostable at home or in industrial composting facilities,” says the firm’s sales manager Martin Peacey.

“It is made by mixing the starch with other biopolymers and oil-derived co-polyesters, and the resulting molecular structure ensures that it is fully metabolized by micro-organisms into carbon dioxide, water and organic humus.

No undesirable particles are created that could find their way into the food chain.”

The appeal of using a decomposible wrapper with a more natural end-of-life has prompted other organizations to follow suit, with both the Guardian and the Times now using potato-starch wrappers to distribute their weekend supplements.

At Advanced Direct Mail (ADM) – the mailing company used by the National Trust and other large membership organizations such as English Heritage and the RSPB – business development manager Jo Lucas says that nearly all of the firm’s clients have adopted the bioplastic wrapping.

“We are now using 90 tonnes of the material every month, and as such a large buyer we have been able to negotiate a very competitive rate for our customers,” Lucas says.

One snag is that the material is opaque, which makes it difficult for postal services to read barcodes printed on the magazines for automated sorting – such as those used in Royal Mail’s popular Mailmark system.

But ADM has been working with Alfaplas to make the film slightly more transparent. “We have replaced a single 24 μm layer of Bioplast with three much thinner layers, producing a film with a thickness of just 21 μm,” explains Peacey.

After some successful trials, Lucas says that an entire mailing of National Trust magazines was sent via the Mailmark scheme without any problems.

The potato-starch wrapper is still not an ideal eco-solution, however.

“Not all councils will accept it in their recycling collections, and consumers are confused about the best way to dispose of it,” says Prichard.

This becomes a real problem if starch-based compostable wrappers are taken for recycling with plastic carrier bags: the two materials must be treated differently and the whole batch of recycling can become contaminated.

Another problem is that some bioplastics degrade too slowly for industrial composting facilities that use anaerobic digestion to treat food waste, which means they just float to the top and must be removed.

Worse still, a compostable wrapper is designed to be used only once, which means that the energy used to create it – which Peacey says is comparable to the polymerization process for LDPE – can never be recovered.

Bioplastics also continue to incorporate materials derived from fossil fuels.

Bottom line: biowrappers can reduce plastic pollution, but are not a perfectly sustainable solution.

New solutions to recycling plastic film

Plastic film – such as the low-density polyethylene (LDPE) polywrap used for years to wrap print copies of Physics World magazine – can be recycled, although that often means having to take it to your local supermarket.

One company keen to recycle plastic film from such stores is Polystar Plastics in the UK, which has recently invested £5m on new equipment to convert it into a material called PCWflex.

According to the firm, the material can be made with anything between 30 and 100% recycled plastic, and has the same properties as “virgin” LDPE.

But the lack of a reliable supply chain makes Polystar Plastics’ business model precarious. “These greener options are much more expensive than virgin LDPE, partly because it’s incredibly difficult for us to find material that’s suitable for us to reprocess,” says Polystar Plastics account manager Steven White-Taptiklis. “We have contracts to buy back plastic waste from certain retailers and resupply them with plastic products, but the government needs to help local authorities improve their roadside collections and prevent cross-contamination between different waste streams.”

Some of those problems could be addressed instead by using chemical techniques to break down the polymer chains.

For example, Recycling Technologies, a start-up based in Swindon, UK, uses pyrolysis to transform plastic films and laminates into a hydrocarbon oil called Plaxx, which serves as a feedstock to make new plastics, including food and medical packaging.

High temperatures are needed, but non-condensable gases generated during the process are captured to provide some of the thermal energy, making it up to 85% energy efficient.

Recycling Technologies has already built a pre-production machine for research, training and initial trials, and now plans to build a commercial system that can reprocess 7000 tonnes of plastic waste per year by the end of 2020. Its system is small, modular and cheap, meaning that units can easily be installed within existing recycling facilities.

The firm has also teamed up with TOTAL, Mars and Nestlé to show that plastic waste in France can be turned first into Plaxx and then into virgin plastic.

“This will be a fantastic demonstration of how plastic can be a truly circular economy material,” says Elena Parisi, Recycling Technologies’ sales and marketing director.

Other firms are developing similar chemical recycling approaches too, but a 2019 study by Brussels-based pressure group Zero Waste Europe warns they are unlikely to reach large-scale production before 2025.

It also suggests that the broader environmental impact of chemical recycling has not been properly evaluated.

That could, it says, leave “a risk of putting too much expectation on a solution whose potential is yet to be proven”.

Paper solution

So if there are problems with both polywrap and starchy wrappers, why not ditch polymers altogether?

Paper seems a much more attractive option, since it is routinely recycled and comes from a sustainable source.

Until recently, however, there wasn’t a viable paper-wrapping solution for magazines. Traditional envelopes aren’t practical for large mailings because each magazine would have to be inserted by hand rather than by machine.

What’s more, the envelopes’ mass increases postage costs and overall carbon emissions.

Large publishers have therefore worked with their print suppliers to introduce lightweight paper wrappers that add negligible extra mass.

National Geographic was the first high-profile magazine to switch as part of its “Planet or Plastic?” campaign, and now sends 2.5 million copies wrapped in paper to subscribers in the US, UK and India.

Country Life magazine has also moved to paper for its 20,000 postal copies, while London-based publisher Immediate Media has switched around 50 titles – including 12 BBC-branded products – to paper wrapping for all posted copies.

“We first introduced paper wrapping in March 2019 for BBC Wildlife and Countryfile magazines, and we have been using it for all 520,000 subscriber copies since the beginning of this year,” says Louisa Molter, Immediate Media’s production manager. “We are committed to reducing our impact through the whole distribution chain, and we felt that paper was the easiest material for our readers to recycle.” Molter discovered, however, that the industry wasn’t initially geared up for paper and it wasn’t easy finding a supplier that could offer paper wrapping in large enough quantities.

“But many of the big players have since converted and there is now enough capacity to meet our needs,” she adds.

One of the earliest adopters was Stephens and George, which in March 2019 was the first printer in the UK to install a paper-wrapping machine.

“It was only the second installation for the manufacturer,” says the firm’s estimation manager Gareth Collins.

“It was a real challenge to get the process right, and there were lots of hurdles to overcome that even the machine manufacturer hadn’t anticipated.”

The effort paid off, with around a quarter of the company’s client base now sending their magazines in paper wrap.

Immediate Media has also worked with its distribution partner, Mailing and Marketing Solutions (MAMS), to refine the process and minimize the difference in cost, with MAMS having invested £1m over the last 12 months to install three dedicated paper-wrapping lines.

“We have agreed prices that are sustainable for us and close to cost-neutral compared to polywrap,” says Molter.

“But that took quite a bit of commitment from our suppliers, and in turn we have made a commitment to put a certain volume through them.”

That’s torn it

After weighing up its options, Physics World believes that paper is the right choice for this magazine.

Indeed, it was all set to change this month before the COVID-19 pandemic put those plans on hold.

But the switch to paper will happen – and the good news, according to Immediate Media, is that while some paper wrappers do get torn or damaged, the magazines themselves remain in good condition.

Molter admits though that not everything has gone smoothly for Immediate Media.

“It’s an evolving journey and we have not yet nailed the perfect specification – particularly for overseas mailings handled by multiple distribution and postal services,” she says.

But most of their readers have responded positively to paper wrappers and the organization is sending out ever-fewer replacement copies.

The big advantage of paper is that it is easy to recycle, and previously used paper has become an important feedstock for the paper industry, where it is widely combined with fresh wood to reduce the energy needed to produce new paper with good mechanical properties.

Indeed, according to the Confederation of European Paper Industries (CEPI), the energy used to make a tonne of paper fell from 15.7 GJ in 1991 to 12.9 GJ in 2017.

That’s far less than the 77 GJ needed to make a tonne of LDPE.

Paper producers have also reduced their reliance on fossil fuels.

More than half of their energy requirements are now supplied by renewable biomass – such as burning discarded bark – and most modern paper mills recover waste heat to reduce their use of primary energy.

But paper’s not perfect either. CEPI estimates that Europe’s paper and pulp industry still emits 32 million tonnes of carbon dioxide per year – that’s 1% of all EU emissions.

You also need about 35,000 litres of water to make each tonne of product, since paper is usually produced by cooking wood chips and recycled material in a chemical bath containing sodium hydroxide and sodium sulphide.

The resulting pulp is mixed with chalk, clay and other fillers, along with chemical additives like titanium oxide, before being squeezed through rollers to remove excess water and then dried through steam-heated rollers.

Much of the waste water is teeming with pollutants such as nitrogen, phosphorous, suspended solids, iron, manganese and organic compounds that don’t easily degrade.

And although on-site treatment facilities have led to the chemicals in the waste water from papermills plummeting from 23 kg to 5 kg per tonne of paper over the last 30 years, reducing the impact of paper production on rivers and oceans is a work in progress.

Paper manufacturers are also under pressure to cut emissions of sulphur compounds and nitrous oxides into the air.

A naked future?

So with no perfect wrapper available, why not send Physics World with no wrapper at all? Dubbed “naked mailing”, this solution has been adopted by the Chartered Institution of Wastes Management (CIWM), which in 2019 relaunched its own membership magazine as a bi-monthly title called Circular.

“We looked at all the different options available to us for making the magazine as sustainable as possible,” says Paul Sloggett, the CIWM’s head of member engagement.

“We use 100% recycled paper and now avoid any sort of waste by sending it without a wrapper.”

And for anyone worried that the magazines might have got torn in the post, only two of the first 5500 copies that the CIWM sent members were reported as being damaged; even then the recipients weren’t particularly bothered.

But could naked mailing work for Physics World, which often sends supplements, such as its series of subject-specific Briefings, as well as inserts from advertisers and the Institute of Physics (IOP)?

And would naked mailing work given that lots of Physics World copies are sent overseas?

In the case of Circular, Sloggett says it uses paper wrapping when supplements are delivered with the magazine, and inserts are only included for those issues.

Binding in supplements to the main magazine is another option, although that might not go down well with advertisers.

You might even be wondering why Physics World sends print copies of its magazine at all.

There’s been a digital app-based version of Physics World for many years, plus the website is more popular than ever.

So why not just ditch print entirely? Problem is, lots of readers and advertisers still enjoy reading a physical product.

A monthly print copy of Physics World magazine is also, for many readers, a tangible sign of their membership of the IOP and one they enjoy landing on their doormat.

So rest assured, the print issue of Physics World is still going strong.

And while the disruption caused by the COVID-19 pandemic meant that Physics World was unable to switch to paper wrapping this month as planned, the change should happen soon.


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Physics World Unwrapped

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