Cartons have seven lives

They protect milk, apple juice or tomato sauce. Almost everyone uses beverage cartons, and then throws them in the Yellow Bin. But what happens after that? The colorful packages are transformed into fine brown paper. We accompany a carton on its journey through the recycling plants.

Walls made of paper: a fork-lift truck brings presorted bales with beverage cartons and light-colored waste paper to the shredder.

An air jet pushes beverage cartons off the conveyor while permitting other packages, like yoghurt tubs, to zoom ahead to the next station – our waste first has to be sorted. On the conveyor belts of the sorting system, this is nowadays largely performed automatically. With the aid of light, camera and computer, the system detects the material the products from the Yellow Bin are made from. A beverage carton consists principally of cardboard, plus some polyethylene film and aluminum. For paper manufacturers, the long, tear-resistant cellulose fibers are particularly valuable. But how can they best be extracted from the composite mixture?

The material is shredded, before the paper contents are softened in the drum pulper.

This is not done in the sorting plant, but at the Niederauer Mühle paper factory in Kreuzau (North Rhine-Westphalia), for example. It’s to here that a majority of the cartons collected throughout the state are delivered: in compressed bales several meters high and weighing over 600 kilograms. Sauce packs huddle up to milk cartons and orange juice containers. A few flies are crawling busily all over them. It’s hot today. Fork-lift truck drivers are unloading the arriving lorries, and piling several layers on top of each other. Next to them are towering piles of other waste paper.

All this has to be properly organized and correctly routed. “Beverage carton in, new paper out – this process takes us just two and a half hours,” reveals proprietor and Managing Director Holger Autenrieb. He takes us into Europe’s biggest plant of its kind.

All the processes are monitored by Jacek Melcher in the control room.


Film and aluminum flakes are left over. This “candy-floss of our civilization” is checked by Department Manager Roland Rameil, before it is bundled and re-used.

Candy-floss made of film and aluminum
A labyrinth of gray pipes, conveyor belts and metal stairs. A red fork-lift truck rolls quietly round the corner, heaves one of the bales onto the conveyor belt. The cartons disappear in a steel box, where they are shredded into hand-sized pieces and then passed to a rotating drum of imposing dimensions: ten meters long, with a diameter of three and a half meters. It hums like a washing machine, and functions more or less like one as well, but without using any chemicals. Mixed with warm water, the material is lifted by scoops. When it is dropped again, the impact detaches the softened paper contents.

These flow into another drum, where the pulp is washed away through small holes. The entire washing operation takes about half an hour. The solid cardboard has been transformed into a watery brown pulpy mass. It is then carefully cleaned: right next to it are the glittering remains from the rinsing process – between the grains of sand you can see paper clips and glass fragments.

In the end, the machine spits out what didn’t fit through the small holes: especially the coating made of plastic and aluminum, thousands of plastic closures, but also everything that had been incorrectly sorted. White-gray piles tower up. The candy-floss of our civilization feels fluffy. It’s not edible, but can definitely be re-used (see information box).

Paper fibers are no longer discernible at this point; they are at this moment being sorted, ground and pumped to the paper machine, rigorously monitored by Department Manager Roland Rameil. He’s been in this job for 27 years. “Meanwhile, all the processes here are acquired digitally,” says Roland, and points to several monitors in the control room. “Over the years, we’ve significantly refined the recycling of beverage cartons.”

Pioneering work
It was a bold move when the Niederauer Mühle decided to specialize in processing beverage cartons as well as waste paper. Supported by the carton manufacturers, the plant went into operation in 1999. “I’ve never regretted this venture, even though the processes involved have become more complex,” reminisces paper engineer Holger Autenrieb. It’s a nuisance, he adds, when you find too many foreign substances in the bales. The sorting technology will be still further improved, so as to recover as many raw materials as possible.

The family firm, employing 175 people, produces the base material for new packages like shoe cartons or pizza boxes. White-covered corrugated board base papers is the technical term employed. They are made 100 percent from waste paper, 300,000 tons of it a year. The cellulose fibers of the beverage cartons take on new life in the brown bottom layer, while the white top layer is made from light-colored waste paper– collected in department stores and printshops.

A paper machine looks like a long concatenation of rollers, turning wheels and steel stairs.
The heat is like a sauna, since the tender fibers are dried at a temperature of over 100 degrees Celsius.

The next hall houses the paper machine, a long concatenation of thick rollers, turning wheels and steel stairs. It’s getting noisy now – a piercing whistle assaults our ears. The higher you climb on the grid stairs, the warmer it gets. From above, you can see how the fibrous suspension is being distributed over a gigantic flat sieve. At first, the fiber content is a mere five percent; after initial “dehydration”, it’s already 20 percent. After that, the brown layer is aligned and compacted with the white surface layer. The heat is like a sauna: white vapor rises when the paper web races sinuously over metal cylinders heated to as much as 100 degrees Celsius.

The fresh paper reel weighs 40 tons before it is cut to the desired width.

Paper machines are big: it’s a long way to the end of the hall, where a fresh paper reel weighing 40 tons rests on gigantic hooks. The paper is now cut to the width desired by the customer, and within a few hours is loaded onto the waiting trucks. The plant in Kreuzau supplies packaging manufacturers all over the world. Between the towering paper reels it’s almost never quiet; work goes on round the clock here, in four shifts.

Better than its reputation
When you look at the cartons’ eco-balance, they possess unequivocal advantages relative to other non-returnable beverage packages. Moreover, the ifeu Institute has calculated that compared to refuse incineration of beverage cartons, their recycling produces 20 percent less greenhouse gases, which every year means approximately 55,000 tons less of CO2 in the planet’s atmosphere.

Beverage cartons are popular: on the German market alone, 175,000 tons of them are sold each year, corresponding to about eight billion units. Around 70 percent of these end up in a plant like that in Kreuzau. Their recovery capacities are being well utilized, but are not yet at their limits, which is a good thing: with the new German Packaging Act as from 2019, the recycling target for beverage cartons will rise as well. It’s important that consumers dispose of them correctly. Once they’re empty, they belong in the Yellow Bin.

Two and a half hours have gone by, there’s nothing more to be seen of our carton. It’s impressive to watch how quickly used packages are transformed into pure paper. An elaborate process, but it’s worth all the effort. Paper fibers are a bit like cats – they have seven lives, which means they can be re-used up to seven times.

The paper doesn’t stay in the warehouse for long – it’s promptly loaded onto trucks at Niederauer Mühle.