Europe is quite literally littered with landfill sites, some still operational, many long since closed. In a bid to recover both land and materials from these sites, Recycling equipment manufacturer STADLER has taken part in the EU-funded NEW-MINE project.
Europe, there are between 150,000 and 500,000 landfill sites, of which an estimated 90% are “non sanitary” landfills predating the EU Landfill Directive of 1999. Enhanced Landfill Mining (ELFM) has the potential of providing a solution that could dramatically reduce future remediation costs and reclaim valuable land while unlocking precious resources.
The four-year NEW-MINE research project, led by KU Leuven Institute for Sustainable Metals and Minerals SIM2, was launched in 2016 to look into different aspects of Enhanced Landfill Mining. Its aim is to develop and integrate cutting-edge, eco-friendly ELFM technologies to valorise Europe’s landfills, recovering resources such as materials, energy and land, while mitigating future environmental and health risks and avoiding significant remediation costs.
“We consider Enhanced Landfill Mining the missing link to a Circular Economy,” explained Dr. Lieven Machiels, Science & Technology Coordinator of the project at the KU Leuven Institute for Sustainable Metals and Minerals. “The Circular Economy Action Plan of the European Green deal focuses on a ‘sustainable products’ policy that prioritizes reducing and reusing materials before actually recycling them, moving up the Waste Hierarchy.”
“Nevertheless, what is not yet addressed is the question of what Europe and other countries in the world will do with the vast amounts of industrial and consumer waste that have been disposed of in waste dumps and landfills over the past 100 years. In this context, ELFM has been proposed as an out-of-the-box approach to address how we can deal with the waste of the past, irrespective of the urgent need to avoid new waste creation and disposal in the future,” continued Machiels.
The project has received funding from the European Union's EU Framework Programme for Research and Innovation Horizon 2020 and involves eight European universities as well as STADLER and other companies from the private sector.
Machiels explained that in classic Landfill Mining, the focus is on reducing the volume of waste, for example through incineration and the recovery of land, while the production of recyclates is in general limited. NEW-MINE however aims to thermally convert the light fraction to produce a synthetic gas and a vitrified residue.
RWTH Aachen University, one of the project’s partners, invited STADLER to participate, contributing its expertise and equipment. The company played an important role in the first work package, dedicated to mechanical processing.
The main goal was to identify ways of improving the quality of the fractions in order to produce RDF, which has a variety of applications. Another important goal was to research uses for fine fraction, which accounts for more than 50% of the waste in landfill mining, and currently has no utilization.
The project showed that further mechanical separation of fine fraction can produce sand for use as an aggregate in the construction sector. The light fraction can also be used in a thermo-valorization process.
STADLER also contributed to the Training Programme associated to the project with a course on “Automated sorting technology for complex waste”, which was held during the second NEW-MINE Network Event for the fifteen participating PhD researchers.
The theoretical research on mechanical processing was tested in real conditions in the Mont-Saint-Guibert landfill in Belgium. The landfill waste was excavated and processed.
Ulrich Sigmund, Head of Research and Development at STADLER, described the process: “An STT6000 Ballistic Separator was used in the first step of the mechanical treatment for the recovery of RDF and other recoverables, such as metals and inert materials. The machine separated the output in three fractions – fines, rolling fraction and flat fraction – which were then treated separately in order to investigate further recycling possibilities.”
One significant challenge in the project was the fact that the excavated waste had to be processed on site, so the Ballistic Separator had to be installed on a temporary concrete foundation in the landfill.
The STADLER Ballistic Separator has overcome all the challenges, showing that it can perform in these difficult conditions and confirming the feasibility of the project: “The high moisture value of the material was very challenging because the input was composed of pieces of rock and lumps of earth of up to 100 kg,” said Sigmund.
Mr. Christian Nordmann, Deputy Head of Research and Development at STADLER, who worked actively on the tests in Belgium, added: “The machine is very robust due to the two drives and central lubrication during operation. Also, the bearings are very well sealed, so the machine can operate outdoors. This enables the STT6000 to deal with the challenges found in the excavated landfill material, such as high moisture, dust and impact. In the tests we were able to model the material separation, including mass distributions and material parameters of the derived fractions.”
“The tests showed that a new approach of starting a recycling process with a separation in three fractions is possible. This saves wear and energy compared to standard processes with a shredder/screen combination,” concluded Sigmund.
For a more in-depth look at the project don’t miss the September/October print issue of Waste Management World – subscribe HERE
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