| 摘要 |
<p>A permeable wall (4) is located in the material of an aquifer (2), in the path of an approaching plume (3) of a contaminant (eg a chlorinated solvent). The wall comprises a body (7) of permeable filler material, eg sand and gravel, which is placed in a trench (5) that has been cut down into the aquifer material. Biologically-aided breakdown of the contaminant is aided by the presence of nutrients in the groundwater, and injection ports (18) are provided in the wall, through which the nutrients are injected periodically. The permeability of the wall helps the injected nutrients to spread laterally through the plume. The injected substances are contained in a volume of water; this water may be water which has been extracted from the trench, draw-off wells (9) being provided in the trench for that purpose. A second permeable wall (29) may be provided downstream for injection of eg air.</p> |
