17. In-situ washing

Another keyword: flushing

In-situ scrubbing involves percolating a solution onto the soil to extract the pollutant. Water or a solution of mobilizing agents can be used as the washing solution. The fluid is injected into the soil and then recovered by pumping (figure 17 ). This technique generates large volumes of effluent to be treated, but it has already been tried and tested on a number of sites for the treatment of soluble molecules.

• Principle

  The process consists of injecting a washing solution (water or mobilizing agents in solution) upstream and pumping it downstream of the polluted zone, generating fluid movement through the contaminated zone and loading the fluid with pollutant. A pollutant-laden...