construction

Finding concrete solutions

Construction and demolition waste is a mysterious area. Obtaining decent statistical information on household waste can be a struggle, but the problems are hugely multiplied in the C&D sector, where coherent definitions and record-keeping appear all but non-existent.

One thing does appear certain; construction projects generate a lot of waste material which is bulky and difficult to dispose of. In rapidly-developing economies such as China, the problem seems especially acute. A recent newspaper article highlighted the example of Shenzhen, a city built from near-scratch over the past three decades. If you have an old world atlas printed in the 1990s or earlier, take a look. Chances are, Shenzhen won’t even be marked (it’s next to Hong Kong). It now has a population over 12 million. That’s a lot of construction in a short time, and a lot of resultant waste. Simply sending it to landfill is a poor use of that resource, and there are growing environmental pressures for less– or even better, more intelligent – use of concrete and other building materials.

In China and many other developing economies, waste from construction seems, at best, to go into landfill or at worst is just dumped wherever it is least likely to be noticed. India is notable as an exception; a developing economy where attention is being paid to the C&D issue.

In developed economies, there is far more investment into recycling of C&D waste. This typically involves crushing and sorting materials into sand and aggregate for reuse in the building industry. There is also increasing effort into maximising the amount of material that can be reclaimed (see below). More can be done, however. As data gets better regarding the amount of C&D waste generated, the opportunities will become more apparent. Once again, here is a specialised and ‘difficult’ type of waste which can be seen as a commodity with value, rather than just a problem to be dealt with.

The AcuComm database currently lists 67 projects since 2013 dealing specifically with the recycling of C&D waste. These have a total estimated value of US$329 million, or around US$19 million each. The total estimated annual throughout is 12.9 million tonnes, equal to around 600 tonnes per day per facility on average.

These projects are in 17 different countries. The USA heads the list with 19 projects, followed by the UK with 13 and India with 11. Five other countries have more than one project listed since 2013: Australia, Canada, China, New Zealand and Spain.

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One new facility in the field went into operation in January 2019 near Stockton On Tees, UK. This takes construction and excavation waste and converts it into high quality sand and aggregate for use in the building and construction industry.

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The plant, operated by Scott Bros, is capable of processing between 50 and 70 tonnes of waste per hour to produce both coarse and fine sand, together with three grades of aggregate. Currently, some 20% of the wash plant’s output, a clay-based substance produced during the filtration process, cannot be recycled. One possible use being explored is that the material could be incorporated into the brick manufacturing process.

Written by Andy Crofts, AcuComm Chief Data Analyst.

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