The fork in the road for unrecyclable plastics

Europe has to slash its waste to landfill volumes to just 25 per cent of all municipal waste by 2025 - and with the Chinese ban on importing waste from other countries, this presents an enormous challenge for the region.

Forks

Plastics are central to this issue. Plastic waste, in particular plastic packaging and disposable plastics, have become the malignant icons of humanity's carelessness in disposing of consumables, to the detriment of the natural world.

When it comes to plastics and any other materials that have reached the end of their usable life, there are three likely routes for them to take: they can be recycled, incinerated or landfilled. Of these three, recycling is the most environmentally attractive and is held as the ideal outcome to close the plastics circular economy loop. Landfilling is - to many - the most undesirable and must be greatly reduced as a last resort for waste. Then in the middle, we have incineration or waste-to-energy - an environmentally ambiguous endgame for plastic waste.

'The least preferable option'

In Europe, nearly a quarter of all municipal waste (90 million tonnes) ends up being directed to waste-to-energy facilities. There are some 450 serving European countries altogether and according to current CEWEP (Confederation of European Waste-to-Energy Plants) data, the highest concentration of these plants is in France (126 facilities), Italy (40 facilities) and the UK (37 units), with clusters in Scandinavia and the Benelux region. There are far fewer in Eastern Europe where landfill is still the most-utilised form of waste management and recycling systems are still being developed.

Landfilling has been widely declared an unsuitable waste management route, with the European Commission describing landfill as "the least preferable" option.

Puente Hills

Sky view of Puente Hills landfill in Los Angeles.

Via Wikimedia Commons

There are numerous public and environmental health reasons why landfilling is undesirable and unsustainable. Just as coal is being scraped from the mines of the world like the last ice cream in the tub, the rubbish bins of the world are overflowing, pushing the earth up to as much as 150 metres high across sites spanning hundreds of acres, such as the Puente Hills landfill in Los Angeles, US.

In these vast rubbish sites, toxic chemicals are leaching into the soil, poisoning groundwater, while the decomposing waste within releases landfill gas comprising 50 per cent methane and 50 per cent carbon dioxide.

'Zero waste to landfill' is an admirable target for any country or organisation to set out, but if that is the case then unless a product can be reused or repurposed, the product reaches a fork in the road: recycling or waste-to-energy.

There are many reasons why the recycling path may be blocked for that product. Perhaps the product is made of mixed materials that cannot be separated chemically or mechanically and therefore it cannot be recycled effectively, or the infrastructure for recycling and processing the materials simply does not exist. If it cannot go to landfill, then the item is bound for waste-to-energy.

Waste for heat and electricity

We are taught early on that burning plastics is unacceptable because plastic releases toxins into the atmosphere when incinerated. But waste-to-energy converts the heat generated in the incineration process into energy.

According to CEWEP, 90 million tonnes of waste that cannot be recycled in Europe is taken to waste-to-energy plants, where it is incinerated to produce 39 billion kWk of electricity supplying 18 million homes, and 90 billion kWh in heat for 15.2 million homes.

Burning plastic may be environmentally reprehensible in principal, but the fact that waste-to-energy plants prevent between 10 million and 49 million tonnes of fossil fuels from being consumed annually is a sustainability counterweight to this.

Rinterzelt

The Rinterzelt waste incineration facility, built in Austria in 1980.

Modern waste-to-energy plants, CEWEP states, filter the emissions generated in incineration and between 1990 and 2000, dioxin emissions generated by Germany's waste-to-energy plants dropped to less than 0.5 grams per year from 400 grams. The amount of thermally treated waste more than doubled over this timeframe. Older facilities are also being retrofitted with these filters in order to meet clean air targets.

Incineration provides an alternative to landfill for difficult-to-recycle plastics such as multi-material pouches, wrappers, contaminated plastics and polystyrene packaging. These materials are extremely slow to break down in the environment and cannot be repurposed as a recycled plastic material. Where landfill space is limited, incineration is preferable, while plastic makes a better fuel than most other materials as it generates a lot of energy.

Unregulated landfill

There are concerns that allowing incineration a place at the table will inhibit recycling, leading to more chemistry being lost.

Indeed, there are fears the Chinese waste import ban denies Europe the luxury of time to fully develop its recycling technology and infrastructure, particularly as 51 per cent of the world's exported waste used to end up in China.

However, rather than being overrun with surplus waste bound for the Chinese market, Managing Director at CEWEP Ella Stengler told EPPM that there is hardly any more waste arriving at European incineration facilities, prompting fears the waste is being sold on to other countries in Asia and Africa where it is likely to be landfilled at poorly-regulated sites.

Far better, she said, that the waste is sorted and what can be recycled is recycled and what has to be incinerated goes to waste-to-energy.

"Waste-to-energy fulfils a hygienic task for our society," said Stengler. "This means substances of concern embedded in the waste should not re-enter the cycle and waste-to-energy takes care of them.

"For some [plastics], recycling is already today the way to go. For others, recycling might not always be the sustainable way and in these cases energy recovery can be the more sustainable solution, and it is definitely the better option that landfilling plastic waste, which should not happen at all."

Balancing incineration with recycling

Stengler is not in favour of incineration over recycling, rather finding the right balance where carbon efficiency is concerned, and using all the technologies available.

The European Commission's January 2018 interface between Chemicals, Products and Waste Legislation states that the two main objective of the circular economy are recycling, and to reduce the presence of substances of concern. Only quality recyclates, Stengler stated, are accepted by the market.

"We cannot emphasise enough the importance of quality for recycling," she said, nevertheless, Stengler does not believe waste-to-energy threatens the incentive to recycle plastics.

"Capping waste-to-energy would not incentivise recycling because it deals with the rejects of recycling and waste that is not good enough for recycling, either because it is too polluted or for instance after several recycling cycles it is not possible to create another quality product. Recycling and waste-to-energy go hand-in-hand. Quality recycling is only possible if waste-to-energy takes care of the components in the waste that are not suitable for recycling."

Rethinking landfill

Materials that are not good enough for recycling for whatever reason may have a different fate altogether, however.

Keith Freegard, Director at Axion Polymers, believes that if we take a fresh look at how we approach landfill, there is no need to ever lose valuable chemistry from burning polymer products instead of reprocessing them - even if we cannot reprocess them using today's technology.

Freegard is by no means staunch anti-incineration but believes burning long-life carbon such as plastic products is inefficient, as the molecules will end up in the atmosphere. Unlike landfill, where the materials can be mined and recovered at a later date, 'skyfill' - as Freegard calls it - loses that chemistry into the atmosphere with devastating environmental consequences.

There is a subset of waste, he believes, that should be directed towards incineration, predominantly short-life, renewable carbon such as paper, cotton wool, nappies, paper food packaging with food waste contamination and sanitary products.

"Right now, it might only make sense to separate out PET bottles and HDPE bottles and turn that into a recycled material, but all the stuff I'm left with I should accept some sort of stewardship for. And right now the economics and the legislative structures say we should just burn it for energy - but what else do you do with it?

"It might be better separating the plastics and storing them in a controlled cell in a landfill site. If we separate the crisp packets and trays out of the waste stream putting them in a cell in a landfill site is a bit like creating your own oil well that you can got to in the future to drill the oil out when the economics and technology suits down the line."

By separating the short-life carbon, the food waste and the organic waste for incineration, directing the plastics to landfill will not have as many hazardous side effects, Freegard explained.

Bales of plastic

Zero plastics to incineration

"I sometimes think landfill gets are really hard time," he said. "Uncontrolled landfill, rotting away, producing gas is bad, but if we had zero organic waste to landfill, the segregation of food waste and if we sort the long life carbon from the renewables and only combust the renewables, locking the long term carbon molecules into landfill cells, you're creating your oil field of the future. If it's 90 per cent plastic in a landfill cell, it wouldn't be a methane risk. But it's only going to happen if somebody changes the metrics."

By 2020, the European Commission dictates that member states must prepare 50 per cent of its waste for re-use and recycling, with landfill tax incentivising recycling schemes. However, established waste-to-energy contracts with local authorities runs the risk of pushing materials into waste-to-energy that could be mined for their chemical properties later on.

Nevertheless, Europe has to meet waste management targets of cutting waste to landfill to just 25 per cent by 2025. CEWEP states that this will not be possible looking at all the data available to us today without waste-to-energy.

"When I look at Eurostat figures, none of the Member States who landfilled less than 25 per cent of their municipal waste achieve this without waste-to-energy," Stengler explained. "Waste-to-energy is a prerequisite for both landfill diversion and quality recycling."

Until such a time that only renewables go to landfill, preserving the quarries and salt mines of the earth for storing plastics and other long-life materials to be recycled in the future, it seems incineration and recycling will be the preferred options for plastic waste.