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Spraying steam into soil contaminated by organic pollutants such as PCBs can
dramatically cut the time and cost of decontamination. Instead of waiting for
pollutants to percolate slowly into groundwater, researchers from Lawrence
Livermore National Laboratory in California use steam’s heat to dislodge
contaminants from the soil. Injecting air then triggers an oxidation reaction
that renders most organic pollutants harmless. In a pilot project, the process
got rid of 250 tonnes of waste in 9 months—standard treatment would have
extracted only 125 kilograms in the time. Steam also costs about two-thirds
less.