The smart machines that sort through recycled paper
A single sheet might be, as they say, 'paper thin', but the paper business is colossal. Global paper demand reached 400 million tonnes in 2011, up by almost half since 1980. Paper's environmental impact is equally huge, affecting forests, energy, water and other resources. Thanks mainly to recycling, its environmental footprint is getting smaller, but a European Union research project is helping make it smaller still.
The project, named SORT-IT, has developed new machinery and concepts to improve the difficult task of sorting recycled paper. The innovation is set to make the paper industry both greener and more efficient by using new sensor technologies to separate the plastic from the paper, and sort cardboard from paper.
The three-and-a-half year SORT-IT project, which ran until May 2011, was backed by €2.87 million in EU funding. "Our aim was to improve the quality and yield of the fractions sorted from recovered paper," says SORT-IT's project manager, Jean Yves Escabasse.
Some two thirds of paper products are recycled in Europe. Recycled paper is more environmentally friendly and cheaper to make than new paper made from virgin wood pulp. But manual sorting of the different grades of recovered paper is dirty, arduous and time consuming. Paper and board are sorted in different ways at recycling plants, either for packaging or for newsprint. And recovered paper contains different kinds of trash, like wire, staples, paper clips, and plastic, which must be removed during pulping, cleaning, and screening.
"We wanted to develop automatic identification and sorting machinery, to integrate them into a sorting plant and to demonstrate that they could work efficiently and sustainably for paper industry," says Escabasse. He says the SORT-IT will be especially welcome for Europe's €80 billion paper and board sector, which employs 225,000 people and produces 100 million tonnes a year on 1,400 paper machines.
SORT-IT's optical sensors combined image analysis, colour measurement and near-infrared sensor units to identify the different paper grades. As newsprint, flyers, cardboard boxes, magazines fly by, they can distinguish de-inkable paper (which is reusable for printing material); paper to be used in packaging; and non-paper like plastic bags or sheets, which is usually incinerated.
But the breakthrough, Escabasse says, was to join the infrared spectrometry with sorting technology. "Anyone can tell the difference in a coloured paper mix. But to separate, you need arms," he says. "So we coupled these cameras with sorting machines, which were computer-controlled robot arms and pneumatic blower ejectors using compressed air that can carry it out. All this has to run on sorting machines fast enough to sort tonnes and tonnes per hour. So far, robots cannot match the speed but they will soon catch up."
SORT-IT gathered 13 European partners. Coordinated by the Munich-based Papiertechnische Stiftung (PTS), the research arm of Germany's paper industry, it was implemented at full scale on the site of the Austrian small company Rauch Recycling in Linz. The machines, on the market since mid-2010, can sort 2,000 tonnes per month, or 10-12 tonnes per hour. They can achieve a paper recovery yield of 95% for all recyclable paper and board grades and a purity of 98% in wanted materials.
Escabasse says an essential part of the project was to demonstrate its sustainability with a full-scale life-cycle analysis. "If you have better quality recycled paper, it means less waste and fewer raw materials – all with the corresponding reduction of emissions for transport, less energy with the machines, and fewer paper additives," he says. "So this is economically, environmentally and socially sustainable."
Project acronym: SORT-IT
FP7 Project N° 211888
Participants: Germany (Coordinator), France, Sweden, Norway, Spain, Denmark, Romania, The Netherlands, Austria,
Total costs: €4 156 810
EU contribution: €2 868 966
Duration: May 2008 - October 2011
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