Phytoremediation of Soil and Organic Compounds

Phytoremediation can be a low cost, effective alternative to the conventional methods of soil remediation. Phytoremediation is the use of vegetation to take up contaminants from the ground or water. Phytoremediation can remove metals from water. However, it is also very effective in remediating soil and organic compounds.

How Does Phytoremediation Work?

Plant roots take contaminants from the ground into the "body" of the plant. The plant root zone is referred to as the rhizosphere, this is where the action occurs. This soil supports large populations of diverse microorganisms. This is due to chemicals exuded by plant roots which provide carbon and energy for microbial growth. This combination of plants and microorganisms appears to increase the biodegradation of compounds.

Phytoremediation Designs

The following graphic shows a typical process diagram of phytoremediation.


Notice how simple the diagram is. Phytoremediation is a very basic process. The setup of a typical one acre phytoremediation site might look like the following diagram.



Contaminants and Contamination Levels

Phytoremediation is effective in the remediation of all types of soil contaminants, however it is more effective on lower concentrations of contaminants. The previous page listed the metals. Some of the organic compounds are:
  • Anthracene
  • Atrazine
  • TCE
  • Pyrene
  • Toluene
  • Phenol
  • Other contaminants from TNT, pesticides, chlorinated solvents, and fuel/oil

    Types of Vegetation Used

    Some of the plants used in phytoremediation are:
  • Alfalfa
  • Hybrid Poplar Trees
  • Blue-green Algae
  • Duck Weed
  • Arrowroot
  • Sudan Grass
  • Rye Grass
  • Bermuda Grass
  • Alpine Bluegrass
  • Yellow or White Water Lillies

    Pros and Cons of Phytoremediation

    Advantages:
    Phytoremediation is cost effective
    It is suited to remediation of large areas of soil
    It is environmentally friendly
    Phytoremediation sites are more aesthetically pleasing
    Phytoremediation sites are low maintenance
    It involves no noisy and expensive equipment

    Disadvantages
    Not as effective for sites with high contaminant concentrations
    Phytoremediation is slower than conventional methods
    It does not work through the winter (Seasonally effective)

    As more research is conducted we can be sure that we will be hearing more about phytoremediation, the low cost alternative.

    Written by:
    Nathan Florio
    and Hayes Rembijas
    Fall 97 Env. Syst. Eng.