In-situ clean-up of contaminated land

People first started to worry about the problems of contaminated land in the late 1970s. The issue that highlighted the problems and became very well known was that of the Love Canal, USA. Love Canal was a canal excavation site used during the 1940s for a dumpsite for industrial wastes that included pesticide residues, process slurries and waste solvents. The site was sold in the 1950s and houses were eventually built on top of the site. In the mid 1970s, a number of the area residents began developing a variety of illnesses and it was considered that the soil and ground water became contaminated with resulting dire consequences to the local population. The US government declared a state of emergency and started the clean-up.

Following this highly publicised case, there was considerable effort in the States and Europe to identify other contaminated sites including military sites. Attempts have been made to clean the contaminated groundwater, initially using a treatment known as 'pump and treat' which involved flushing the area through with water and treating the pumped water. However it is now realised that this process is not effective to remove all contaminants in the ground.

Much of the work of the Geotechnical group at Cambridge is involved with investigating clean up of contaminated land in the ground (called 'In-situ remediation') without excavating the contaminated soil and cleaning up the excavated soil. My research is involved with removing a particular kind of contaminant, known as non-aqueous phase liquids, which are substances such as oil, petroleum and chemical solvents. These substances are volatile, and the assumption has generally been that they would vaporise on disposal and thus get dispersed into the atmosphere. However, it has now been discovered that such liquids actually sink into the aquifer and gradually dissolve into the groundwater.

It became obvious in the early 1990s that more innovative methods need to be developed to clean up the contaminated soil, and that is the focus of our research. Much of the research that has been done in this area has been carried out using small scale laboratory experiments which now need to be up-scaled to see how applicable they are in the field. We have devised intermediate scale tank tests for testing various cleaning up technologies and are aiming to make them more efficient, as well as testing them to see how well they will work in the field.

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Other environmentally related projects:

Assessment of engineering solutions for contaminated land