A new life begins for the Barcelonians' cartons after they drop them in the recycling bin. The cartonwaste is picked up and brought to a municipal sorting plant. After sorting, the used beverage cartons are sold and transported to Stora Enso's Barcelona Mill. The waste does not have to travel far as the mill is conveniently located only 20 kilometres from the city centre.
Our Barcelona Mill receives about two billion used beverage cartons every year. With the help of specialised technology, all parts of the carton can be reused at the plant. The cartons are made of fibre, plastic and aluminium. About 75% is fibre, 20% plastic and 5% aluminium. With no waste, the cartons are given a new life as energy or raw material.
Everything starts from pulper. "Here the fibres in the beverage cartons are washed away from the plastic and aluminium. The fibres are cleaned, and then we make new board out of them. The board will be used for example in food packaging, like cereal boxes. It isn't used for packages with direct contact to groceries though, such as juice or milk cartons," says Mill manager Juan Vila.
The recycling of beverage carton layers sounds perfectly simple and effortless. Behind it, there is, however, innovative use of a technology called pyrolysis. This technology was awarded by the European Union in 2010 for bringing great environmental benefits. Barcelona Mill is the first mill in the world to use the pyrolysis technology on a large scale.
"Pyrolysis works by heating up the plastic and aluminium to a temperature of 500°C, but without oxygen. This way, the plastics do not burn. Instead they transform into gas and oil, which are used to generate energy for the mill," Vila explains.
"And this is what becomes of the aluminium in your beverage carton after being treated in the heat of pyrolysis," he says and picks up a perfectly-shaped aluminium brick. "These bricks will now be sold to aluminium companies. They will make new aluminium products, such as car bumpers, out of them."