BUILT ENVIRONMENT
Brownfield development
COMPOS
CUTS COSTS
From humble origins as a soil improver in gardens, to its commercial
application in large-scale brownfield regeneration projects, compost
has always been recognised as a unique and versatile material, writes
Paul Mathers. And, he says, it can help the construction sector save
costs and boost its environmental credentials
U
sing compost made from recycled gar- metal pollutants; oil refineries leave hydrocar-
den material, such as grass cuttings, bon contamination, and tanneries can leave
prunings and leaves, has always been an soil highly contaminated with chromium.
effective means of improving soil water avail- Traditionally, when working on contaminated
ability and adding nutrients to the soil. The land, developers have preferred to strip the site
many benefits of quality compost are now of contaminated soil and import new material
being realised by the construction and regen- for landscaping. However, the costs associated
eration sector and the product is increasingly with the procurement of material and the
being used in a variety of large-scale commer- disposal of waste are rising, and developers
cial applications. need a more economic and environmentally
For house builders, as an example, improv- viable way to treat lightly contaminated soils.
ing the quality of soil on development sites Again, trials have shown that, while animal
can directly influence the presentation of the manures have been proven to work in this
gardens, parkland and other open spaces being sort of bioremediation scheme, quality
created. Property presentation, both inside compost can also help create optimal
and out, is very important to home buyers. conditions for bioremediation in nutrient-
And, when newly turfed gardens start to look deprived soils. When produced to BSI PAS
dull and aged after just a short period of time, 100 specifications (the quality assurance
this can be detrimental. scheme introduced in 2002) it compares
Fortunately, trials have now proven that favourably with other organic substrates used The costs associated with the procurement of
compost-enriched soil enables rapid turf for this application and is also safe, consistent,
material and the disposal of waste are rising,
and developers need a more economic and
establishment, needing only minimal watering reliable to use, as well as being relatively easy
environmentally viable way to treat lightly
but still offering thick, lush growth to attract to source and procure.
contaminated soils
buyers and subtly complement the rest of the In fact, compost availability in the UK is
built environment. increasing thanks to higher levels of compost
Similarly, compost has an important role to production. In the recent WRAP-funded
play in the regeneration of brownfield sites – Association for Organics Recycling report
both through its capacity to minimise waste into the sector, it was found that in 2006/07
material going to landfill and the way it can be 3.6M tonnes of organic waste was composted,
mixed with onsite resources to create new top- an increase of 5% on the previous year – and
soil. Contaminated brownfield sites can be a huge jump from the 900,000 tonnes
found throughout the UK. And, although in 1999/00. Yet, when looking at the opportu-
there are no definite figures, the Environment nities for using quality compost in brownfield
Agency (EA) suggests that there could be as regeneration, its use goes beyond the role it
much as 300,000 hectares of UK land that can play in decontamination – it can also be
requires decontamination. mixed with existing mineral wastes and
The level and nature of contamination can resources to manufacture new topsoils.
vary from site to site. For example, old mining This was a process used by BAE Systems
operations are likely to leave behind heavy working on a new housing, commercial and
28 June 2009 ❘ Sustainable Business
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