In the middle of an industrial estate in Huntingdon sits an unassuming brown corrugated metal structure which gives no clue to the innovative process taking place within it.
This is Enval’s first commercial scale plant that takes plastic-aluminium laminate packaging – used for the likes of drinks, baby food and pet food – separates out the aluminium fraction for onward sale and turns the remaining plastic fraction into gas to power the process and oils. It does this using microwave-induced pyrolysis.
The facility marks an important stage in the company’s evolution. As managing director and chief technology officer Carlos Ludlow-Palafox admits, getting it up and running took “much longer than anticipated”, as is often the way with start-ups.
‘Commercial scale’ for Enval is a facility that can process 2,000 tonnes a year.
“Now, when I say 2,000 tonnes a year, people look at me and say ‘that’s a toy’ – but it is a lightweight material so people need to understand that,” Ludlow- Palafox says. “We developed a process that was intended to tackle a geographically distributed problem in a geographically distributed manner. The last thing you want is to have a process where you have to ship loads of stuff to a centralised facility in order for that facility to be financially viable.
“We needed to come up with a process that could be financially attractive at a much smaller capacity in order for it to be co-located with MRFs. We turned the problem around and said ‘how much would a MRF, in the fullness of time, be able to collect of [this packaging] – or maybe at a MRF and another that is nearby?’
“For that, we had to ask a number of questions such as what is the market distribution of laminate packaging; how much do we have in the UK; how many tonnes would each unit have to treat. Also, we had to consider that usage of laminate packaging is growing like mad. So we ended up with a number of about 2,000 tonnes a year,” he explains.
This tonnage will be the standard capacity of an Enval unit. The vision is that the technology would be linked to either a MRF, which would take in laminate material, or a paper mill taking in used cartons, where Enval’s technology would process the plastic/aluminium residue.
The bigger area of opportunity for the company is in co-locating its technology with MRFs to process laminate waste, but the collection infrastructure for this is not yet set up. Results from a Defra-funded trial into viable collection methods for this waste stream are due out shortly. Paper mills are already processing drinks cartons, but the question there is whether they would want to invest in new technology that has nothing to do with paper.
Enval’s current business model is based around being a turnkey solution provider for these two types of operation, but Ludlow-Palafox recognises that Enval, being small, is able to be a lot more flexible than its potential customers.
“My two-penn’orth contribution is that the waste handling sector is going to suffer serious changes in the next five years as a result of the circular economy package and so on,” he says.
“We don’t know how that is going to change the way the traditional waste handling companies operate. My opinion is that they will become more focused on resources rather than just mechanical separation and the like. If that is the case, then getting technologies to do the reprocessing and not just the separation could be interesting for them.
“Obviously that goes way beyond Enval. But we need to keep our eyes open and minds clear and say ‘how can we be flexible towards the needs of our potential customers?’”
As an example, Ludlow-Palafox asks whether, with many waste companies in debt, they would be more interested in leasing the equipment: “We would definitely be amicable to having those conversations. Why? Because, as I said, the flexible ones have to be us.”
As for the role the big consumer brands can play in helping to deal with this packaging waste stream, he says: “They have an enormous power towards the consumer and they know how to communicate [with them]. We need to use that power in order to be able to reach the consumer so that the consumer also has some push on what happens to their packaging.”
Another obvious way that the big brands can help is to talk to their waste contractors to ensure that production waste is not sent to landfill or energy from waste, but to an Enval facility instead.
As post-consumer laminate collection infrastructure is not yet in place, the company’s Huntingdon plant is processing industrial laminate waste generated by manufacturers. When I visit, there are bales of Capri Sun pouches ready for processing. These have been diverted to the plant from Coca-Cola Enterprises’ plant in Milton Keynes, where Capri Sun is manufactured in the UK, through its waste management company.
“So at least the production scrap from Milton Keynes is not being burned. I don’t have a problem with incineration except when there are better options to deal with the waste – recovering the aluminium is definitely a better way of dealing with this than burning it,” he says.
Ludlow-Palafox himself is also involved in a company called Alucha, which developed technology used at the former Stora Enso paper mill in Barcelona to separate out the aluminium fraction from cartons. He explains that this technology worked well at mill scale (30,000 tonnes) but could not be scaled down to MRF level.
He also knows of a plant in Brazil, invested in by Tetra Pak, which recovered aluminium from de-pulping waste, and a plant in Finland, also formerly owned by Stora Enso, which used gasification rather than pyrolysis to separate out the aluminium. As far as he knows these are the only other thermo-chemical treatment plants previously used to separate out aluminium from laminates, and all were designed for much larger volumes.
He adds that one of the best ways of knowing that Enval is on a unique path is because of the brands which “have eyes and ears everywhere”. “Nestlé, Kraft, Mondalez or Mars are working with us because they haven’t found anywhere else – it means something.”
Contamination is not really an issue. Back in 2011-12, WRAP published reports on the Enval technology, done at its pilot plant, which showed that, even with significant contamination, the aluminium remained much the same in terms of quality.
“If it is food waste, a lot of it is water. What is not water is organic, and the organic bit will pyrolyse and mingle with the oil from the plastic. Whatever is not organic is water and that will always be reducing the calorific value of the oil. So, as long as you do not have 50% water, it doesn’t really matter,” he explains.
The WRAP trial included taking a sample of black bag waste from the AmeyCespa mechanical- biological treatment plant in Cambridgeshire, separating out the laminates by hand into packaging type, weighing them, opening and washing them to get rid of the contamination, and then drying and weighing them again to find out what percentage of waste was left within the packaging.
It found that the Capri Sun-type of juice pouches had the least contamination because children made sure they sucked out all the juice. Pet food pouches, which are expensive, also had all the meat squeezed out of them, so were fairly clean.
“What does have the most contamination are toothpaste tubes, because even if you squeeze the heck out of the tube, you still leave an out- standing 10% of paste inside it. So when you bin your toothpaste, you bin around 7g of tube and 14g of paste,” Ludlow-Palafox explains.
“That same WRAP report did a lot of testing about separation techniques, and the good thing about laminates is that they have enough aluminium in them to jump in eddy current separators. So that is machinery that is perfectly well-known in the waste handling sector.
“The other type of technology that can separate them are the combined near infra-red induction sensors that TiTech has. They detect metal from the bottom of the belt and detect plastic from the top. And if the computer detects that, at a certain point it sees plastic but it feels metal, it can only be one thing,” he says.
In terms of the aluminium output, Ludlow- Palafox explains that the most important thing in terms of recycling is the metal yield – the percentage which will become molten aluminium – which is what payment is based on. The aluminium yield from the Enval system is currently around 65% but, with further optimisation, it expects this to be 70%.
Aside from the aluminium, around 30% of the plastic content turns into gas that is used on-site, making the plant self-sufficient, while the other 70% or so of the plastic content turns into an oil that can be sold. Currently this is used for heating applications, particularly EfW.
Ludlow-Palafox explains that EfW plants need to start running on liquid rather than solid fuels and a lot of them use diesel, which is expensive: “This fuel burns in exactly the same way. It would be cheap compared with a virgin substitute for heating applications.”
At the moment, the company’s fuel does not have an end-of-waste certificate, so its use in a waste incineration plant is ideal. And if a waste company was to invest in the technology, it could then divert the fuel created at its Enval plant to its EfW plant.
With the business model based on attaching itself to MRFs and post-consumer laminate waste, is there not a fear that, with council budgets under pressure and this being such a lightweight waste stream, it will be a material that is not prioritised? Ludlow-Palafox says this “does and doesn’t” affect it.
“We created a process that is financially attractive to the operator regardless of things like landfill tax. This is because we are recovering a high-value material, aluminium. The Enval technology differs from other pyrolytic technologies for plastic only because we are not tackling the fuel. That is not our idea or mission.
“Our mission is the laminates because there is a high-value material embedded in them that we know we can recycle.”
Laminate Pouches and Drinks Cartons
Composition and Markets
While the inside layers of drinks cartons and laminate pouches are essentially the same, cartons are around 75% paper and only 25% plastic/aluminium laminate.
According to Ludlow-Palafox, few people realise that, when you take the combined amount of laminate packaging available such as tubes, pouches and sachets, it amounts to about 10 times more than the amount of cartons available. So the area of opportunity for using Enval technology is much greater in the laminate pouch sector.
In 2013, industry body the Alliance for Beverage Cartons and the Environment UK, along with paper/packaging producer Sonoco Alcore, opened a carton recycling facility near Halifax, which takes out the pulp and leaves a plastic/aluminium laminate fraction. This fraction is ideal for the Enval process.
Ludlow-Palafox says: “Of around 100 paper mills in the world that carry out the de-pulping of drinks cartons, around 80 fit well with the tonnage needed by an Enval plant. These businesses do from 4,000 to 7,000 tonnes of drinks cartons a year and, at that scale, they will end up with around 2,000 tonnes of laminate, which is what we want.
“So the average tonnage fits really well both with the geographical distribution of pouches at MRF level and those 80 opportunities that are from the paper mills de-pulping the drinks cartons.”