Delivering London 2012: Contaminated soil treatment at the Olympic Park

The creation of the Olympic Park, commenced with the formation of the development platform, on which the venues and infrastructure was built. This was part of the enabling works, and included 2 million m³ of excavation, and the remediation of contamination. To enable the contaminated soils to be reused, a number of soil treatment techniques were adopted: soil washing, bioremediation, chemical stabilisation and material sorting. Soil washing was the main technique, treating around 700 000 m³ of soil by mixing it with water. This removed the fine grained fractions on which the contaminants were predominantly based, creating a filter cake, typically around 20% of the total volume of soil washed. Bioremediation and chemical stabilisation together treated less than 100 000 m³ of soil. A regime of chemical testing was established to test the materials at the excavation stage, manage the treatment and finally validate the final material. With the exception of the final validation, testing was carried out off site in MCERTS accredited laboratories, the bulk of the testing was undertaken in the site laboratory, which also handled geotechnical testing.