Urban mining: the hidden wealth in cities

17 de April de 2018, por em Good practices, Sustainability
Urban mining: the hidden wealth in cities

Ceramics, sinks, toilets and a myriad of discarded household items in Germany are reused or returned to the production line.

Published by the German News Agency DW

Urban centers house tons of materials that can be reused – from buildings to cars to junk mail. Gradually, the so-called circular economy gains importance and helps protect natural resources.

With the reduction of the available natural resources and the continuous increase of the demand, the use of recycled materials is gaining importance, as well as the riches that the cities harbor.

Concrete, bricks or ceramics, for example, can be found in large quantities in many buildings. Common metals such as steel, copper and aluminum and materials such as plastics, plaster, asphalt and wood are also plentiful. In addition, household waste is an interesting source of valuable materials.

The so-called urban mining has many advantages over ordinary mining: the materials are stored in the cities themselves where they are likely to be used again and therefore there is no need for long transport routes. The impact on the environment is obviously less than that of the mining of natural resources.

“As the use of fossil fuels becomes more complex and expensive, the recycling of secondary raw materials will gain in competitiveness,” says Jasmin Mangold of the German garbage management company Bonn Orange in Bonn.

Cada cidadão alemão produz quase 500 quilos de lixo por ano
Every German citizen produces almost 500 kg of garbage per year

Virtually everything is reusable

Each German citizen produces almost 500 kg of waste a year, and Bonn Orange employees work to separate all types of waste: computers, televisions, refrigerators, washing machines, batteries, fluorescent lamps, rubble, oils, paints.

Inks are used to make chalk, oils are used in cosmetics, and electronic devices contain important recyclable materials such as plastic, metals and glass.

As well as abandoned railroad tracks, vacant lots or that forgotten cell phone in a drawer, are also part of the waste produced by mankind buildings, furniture and appliances.

These so-called secondary raw materials can be reused for commercial and industrial production, limiting imports and protecting natural resources and the environment.

A car, for example, represents a large stock of raw materials – even an old rusty car has value. On the internet, there are several retailers looking for gears, doors and other parts. They use or sell the vehicle’s iron, plastic, glass and metal to produce new products. Tires can be turned into road surfaces or insulation materials.

Valuable waste

“We are surrounded by an artificial warehouse of over 50 billion tons of materials,” said Maria Krautzberger, president of the German Environment Agency (UBA).

If in Germany all industrial infrastructure, all buildings and waste were considered as valuable materials, they would represent per capita: 317 tons of minerals, more than four tons of wood, three tons of plastics and 14 tons of metals.

Each year, this urban stock grows by more than ten tons per inhabitant in Germany, according to UBA data. The value of the metals scattered throughout the cities of Germany is estimated at 650 billion euros. Slowly, these materials are beginning to be seen no longer as a burden, but as a fortune.

Circular Economy

“Recycling is a key industry on the road to a resource-efficient circular economy,” said Felix Müller, UBA’s industrial chemist.

The production of a one-ton car, for example, requires 15 tons of primary raw materials, including ores and fossil fuels.

“Secondary raw materials have a high degree of reuse because they do not need to be refined but only melted,” explained Müller. “To produce one ton of electrical steel from scrap, only 0.8 tons of primary raw materials and only a third of the energy are needed,” he says.

At least in Germany, this seems to have been recognized as the way forward. For example, 30% of semi-finished copper products are already made from domestic copper scrap in the country, according to the UBA.

Among the population, recycling is also quite popular. Often people prefer to recycle that bring natural resources from outside or send large quantities of garbage to Nigeria or China. In the European Union as a whole, the circular economy has also been identified as an important objective.

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