explains Jonathan Atkinson British Environment Agency

The arrière-cuisines the least ragoûtantes human development contain these gold mines It is the fantasy that mobilizes several sites in the world to find materials of value in former landfills. At the Chamber of Commerce and Industry, London, a few days ago, dozens of the world's experts made the point, two years after the first Conference of this type, on what the British call "landfill mining" and French "post-valorisation of waste". All are a first observation: the nuggets spark not yet, but the vein will eventually pay.

"Before the 1960s, landfills contain mainly ash, the only waste household valued not." Since then, the garbage mix of kitchen waste, plastics, metals, papers... ", explains Jonathan Atkinson, British Environment Agency. Two years ago, the explosion of the prices of energy and raw materials - such as metals and plastics-, as well as the perspective of their higher prices in the long term, gave an idea to some large consumers and specialists of the waste. Why not retrieve materials contained in the old landfills, once the biological degradation of garbage completed, generally more than twenty years.

Growing interest

Peter Jones, consultant for landfill operators, said the keys to this trend: more than 3 billion tonnes of material recyclable have been buried since 1975 there than in Britain. By aggregating the course of each material, he suggests a potential income of 60 billion pounds, or EUR 71 billion... without integrating the valorisation potential discoveries of gold and precious metals. Potential customers of these deposits, first include cement, who already use of plastic waste, tire or from biomass of streams of recycling to feed their factories very gourmandes. Lafarge currently cooperates with a discharge in Malaysia for testing. "We are concerned especially in emerging countries, because their landfills are little compacted and more rapid biodegradation: fuels are dry", says Dominique Bernard in Lafarge.

Jonathan Atkinson, skeptical yet a year ago, is confident of the potential of mining waste, but warns that the legal framework must be adapted. The French remain cautious, but Sita believes in this way and reflects on a driver. "The difficulty is to motivate trainees on this type of study," smiles a head of the operator. At Ademe, Isabelle Hébé confirms: "We feel a growing interest in the subject," ensures. Several studies are underway to move dumps risky - a threat including from collapsing on the Atlantic coast.

These operations are now well mastered, even if they remain risks. "We are in France 3 or 4 trips of this type per year about." "It's often leave room for a highway construction site or retrieve storage volume", reflects Marc Debos, Veolia waste treatment management.

Real estate restructuring

Reinhard Goeschl leads IUT, one of the few companies specializing in the rehabilitation of the massifs of waste. A Sharjah (United Arab Emirates), his company just remove a discharge of 17 million m3 in just seven months to make room for buildings. Priced at many stages: he must first carefully study the composition of the waste, its harmfulness, and ventilate the underground injection of air massif. Bulldozers then excavent material, which is sorted on site or nearby in mobile centres of separation. The land, principal balance, are reused in earthworks on the site or being cleared. A Sharjah, the Bill did not exceed 10 euros per cubic meter, but this cost exceeds the 20 euros for the discharges of small sizes. "These charges are possible that a real estate project or for environmental reasons in public clients", said Reinhard Goeschl. Confident that its market will grow, he warns that the recovery of waste is still marginal: "we get 3 of our revenues from the resale of the materials, and I doubt that it exceeds 20 term."

Others are more skeptical. Dirk Lechtemberg, who has tested several sites in recent years, throws the sponge: "To the Lebanon or in Turkey, we have found bombs, grenades, guns and one of our machines even exploded." In other countries, as in Turkey, it falls on medical waste. It is risky. And then the plastic or glass that recovered are often too degraded for recycling.