The humble bacon roll hit headlines during the 2015 election campaign for turning politicians into gurners, but the breakfast treat is now gaining fame for inspiring scientists to produce the latest groundbreaking recycling technology.

David Boorman, Business Development Director at environmental services company Enval, explains: “Professor Howard Chase at the University of Cambridge had heard a story about a business acquaintance leaving a bacon roll inside a microwave for so long that it turned in a piece of charred carbon and began to generate so much heat it was actually glowing red.

“This got him thinking about the science at work there and how it might be used in commercial applications to apply heat to specific areas. After looking into the process, Professor Chase came up with microwave-induced pyrolysis, and with it a new solution for a problem waste stream – flexible laminated packaging.”

Although around 160,000 tonnes of the packaging – comprising aluminium foil laminated to plastic – is used in the UK every year, processing options are limited. But that’s where Enval, a spin-out of Cambridge’s Department of Chemical Engineering, hopes to help.

In February 2015, the company began a Defra-funded recycling trial, project-managed by Anthesis LRS, to evaluate the viability of separately collecting flexible laminated packaging from householders
for recycling.

For the nine-month trial, Nestlé (maker of Nescafé refill pouches and Purina and Felix pet food pouches) and Coca-Cola Enterprises (distributor of Capri-Sun) are educating consumers on which of their brands, and wider product ranges like toothpaste and cosmetics tubes and food pouches, can be recycled in the trial. Communications have been undertaken with up to 260 households in each of three local authority areas (Bracknell Forest, Hounslow and Calderdale), asking them to separate their flexible laminated packaging for recycling. The Recycling and Recovery UK division of SUEZ then collects the material for onward processing at Enval’s commercial-scale demonstration facility near Huntingdon.

It’s here that the magic happens, Boorman explains: “Plastic aluminium laminate has historically been a difficult material to process because the foil inside is incredibly fragile. But our mechanically-gentle process can not only recover the aluminium foil… without damaging it, it can also recover the plastic content as an oil for energy recovery or as a chemical feedstock for further processes.”

The patented advanced thermal treatment sees material heated to around 500 degrees Celsius, at which point the plastic layers turn to gas, leaving the aluminium foil intact to be sent off for reprocessing. Around 80 per cent of the gas, meanwhile, is extracted and cooled to room temperature to form an oil that is sold on, and the remaining 20 per cent (largely propane) is used in an electricity generator to power the plant’s microwaves and other ancillary equipment.

It’s a remarkably fast process, too, Boorman tells me. “The demonstration plant is currently ramping up to 16 hours a day, five days a week and is capable of processing 2,000 tonnes of waste a year, or just over 300 kilos of dry laminate per hour. Depending on the material input (toothpaste tubes have less aluminium content than pet food pouches, for example), the process can recoup between 200 and 400 tonnes of aluminium and between 1,200 and 1,400 tonnes of oil.

“It’s self-sustaining from an energy perspective – as it uses the energy recouped from the material to actually power the plant”, Boorman continues. “Plus, as it’s self-contained, there are no other external emissions. So, we think it’s an incredibly attractive piece of technology for waste handlers as it produces a valuable material for recycling, while at the same time recovering the plastics as a fuel, without polluting the environment. It is also small enough that it could potentially be retrofitted to existing waste facilities.”

Indeed, Enval hopes that, if residents prove open to collecting this material separately, more waste management companies will look to install the technology at their own facilities.

Boorman notes that it’s “too early” to announce the results of the trials, but says Enval is “encouraged by what it’s seeing”. He adds: “It’s early days still, but until we can demonstrate that this material can be appropriately collected cost-effectively, waste handlers won’t be incentivised to start separating out laminated packaging from the waste bin – and we really need this to increase recycling and make packaging more sustainable.” We wish them luck.