Urban soils have the potential to remove carbon dioxide from the atmosphere, according to new research published in this month’s edition of Science of the total environment.
The work by New castle and Oxford universities, backed by the Engineering and Physical Sciences Research Council and the Natural Environment Research Council, suggests that 38,000t of carbon dioxide has been captured by the 10ha Science Central redevelopment in Newcastle and the site could remove a further 27,000t.
Newcastle University lead researcher on the project David Manning said: “Urban soils tend to be rich in waste materials such as concrete or metal slag that contain calcium and magnesium. These minerals capture and store atmospheric carbon through the processes of weathering to form carbonates which are chemically stable and a permanent store of soil carbon.”
The site was previously used as a colliery, as well as being home Scottish and Newcastle Breweries, and 30,000t of near-surface coal deposits will be removed from the site before the area is backfilled with demolition material from buildings on the site. Researchers at the universities have said that the carbon released as a result of the coal extraction will be cancelled out by the carbon absorbed by the soil at the site.
Manning explained that the site is covered by approximately 1M.t of demolition material spread in a 0.2m to 6m thick. The material on site originally had an overall carbon capture potential of 65,000t and geochemical analysis suggests that within three years of demolition approximately 60% of this potential has been exploited
Manning said that data from this research provides further evidence of the importance of secondary carbonate mineral formation, and added: “It suggests that engineered soils could be used for carbon capture and storage with the addition and management of suitable Ca/Mg-rich materials.”