29. Aerobic biological treatment

Aerobic biological treatment involves aeration of the polluted areas (which are often low in oxygen) to promote aerobic degradation of pollutants by micro-organisms (figure 29 ). This technique is currently used on a large number of sites contaminated by hydrocarbons.

• Principle

  Biological treatment, whether of excavated soil or of soil still in place, involves using micro-organisms to transform toxic chemical substances into less toxic ones. The micro-organisms used are often bacteria, although fungi play a predominant role in some ex situ treatments. For general information on the degradation mechanism of micro-organisms, see §6 Biostimulation.