Pure water

Nearly half our water supplies come from underground reservoirs, but these are increasingly contaminated with industrial waste that sinks through soil and rock.

A particularly sticky problem is how to extract cleaning fluids used in dry-cleaning processes, for instance, or washing grease off engines. Called 'chlorinated solvents', they literally cling to soil particles in the water.

Now Prof Steve Leharne of the University of Greenwich at Medway has discovered a technique to prise the solvents loose and then pump them out.

He asked the question, “Can we add some sort of particles to the water to make the solvents mobile?” After experimentation he discovered that tiny fragments of iron, known in the industry as functionalised iron nano-particles, both loosened the solvents and degraded them.

The Engineering & Physical Sciences Research Council (EPSRC) is giving £250,000 to Professor Leharne and his team to take the research further. This is their fifth EPSRC project looking at the problem of underground water pollution and how to solve it.