Finding treasure in waste

Engineer in front of the earth

The UN Rio+20 Summit will focus on the green economy as one of the three fundamental pillars of sustainable economic order worldwide. The goal of the green economy is to combat climate change, to distribute prosperity more justly around the globe and to use natural resources more efficiently. Research on the sustainable use of raw materials plays a crucial part in achieving this goal.

The global population will rise from its current seven billion to nine billion by 2050. The greatest surges will continue to be observed in urban areas: in fact, the world's urban populations already outnumber those in rural areas. That figure was a mere 10 to 15 per cent at the beginning of the twentieth century. Because cities consume about three-quarters of the world's energy and there is a higher demand for resources than in rural areas, the rise in population and the generation of wealth will accelerate climate change and further deplete the earth's raw materials reserves. Cities therefore play a key role in the transformation to a sustainable economy. 

Cities become mines for raw materials

 There are 40.3 million people living in Germany's urban areas, and they consume significant volumes of raw materials. The majority of these materials are disposed of as waste products. The average service life of a mobile phone, to name an example, is a mere 2.4 years. Only about three per cent of consumers recycle their telephones, yet discarded mobile phones, fluorescent lamps or plasma TVs hold a wealth of precious parts, including so-called rare earth elements, which are already becoming scarce in industry because of trade policy constraints and increased global demand. As a result, one of the Federal Ministry of Education and Research's funding priorities is for projects that focus on greater resource efficiency. Research for sustainable development addresses a range of issues. It seeks to transform waste management into resource management in which the urban area serves as an additional raw materials mine whose valuables must be extracted, recovered and recycled. Experts call this "urban mining" and it has scientists in metropolitan areas out on a treasure hunt. Prof. Vera Susanne Rotter in the Department of Solid Waste Management at the Technical University Berlin has worked to have the resources that lie dormant in waste channelled back into the economy. She writes of her research: "The production, utilization and disposal of waste are concentrated in urban areas. It will be our task in the near future to coordinate these supply and disposal processes and to boost the quality of life in inner cities." 

Recouping raw materials for production

Other research institutions such as the Institute for Machine Tools and Factory Management (IWF) at the Technical University Berlin, in collaboration with experts in other research disciplines in the ‘Resource efficiency through decentralized cooperation in recycling networks’ (RESUME) project, are also working to secure the resources contained in the urban environment. The goal of this BMBF-funded project is to more systematically recycle raw materials for use in production. But just how can the nearly 6,000 small and medium-sized enterprises that operate within regional and supraregional networks to varying extents be coordinated? How can very small enterprises with a staff of fifteen that dismantles waste products by hand be brought together with large enterprises that require large amounts of usable metals for their blast furnaces? These are but two questions that RESUME seeks to answer. 

The potential of these research projects is enormous. The annual volume of scrap contained in waste electrical and electronic equipment in Germany is about 200,000 tonnes, and only 40 per cent of that is utilized domestically. Most of it is exported to Asia and Africa where it is often recycled under dubious conditions, inefficiently and at high cost to humans and the environment. This could be avoided with the help of new and efficient recycling methods example of gold: at present, only ten per cent of the gold in mobile phones is actually recovered. Experts estimate that the resulting economic loss amounts to up to 7.5 million euros. The recycling rate for other metals such as tantalum and indium is even poorer. There are a number of explanations for this, which include improper separation of waste by consumers, sorting technology that concentrates only on 'mass materials' such as plastic, steel and aluminium, and a lack of metallurgical processes capable of separating the complex mix of resources in electrical and electronic devices.

 A network of scientists at the Institute for Metallurgy and Electrometallurgy (IME) of RWTH Aachen University and the Aurubis copper company are looking to change this. The goal of the research project is to develop an energy- and material-efficient method of metal recovery which does not itself produce any new waste. Until efficient solutions have been found, however, waste products must be separated and not simply disposed of with household waste. 

 

Overview Science Year 2012 "Project Earth"

 

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