Rhizofiltration

Rhizofiltration refers to the use of plant roots to absorb, concentrate, and precipitate toxic metals from contaminated groundwater. Initially, suitable plants with stable root systems are supplied with contaminated water to acclimate the plants. These plants are then transferred to the contaminated site to collect the contaminants, and once the roots are saturated, they are harvested. Rhizofiltration allows in-situ treatment, minimizing disturbance to the environment (Salt et al., 1995).
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The figure below shows the process of Rhizofiltration. []

__Advantages__ - Rhizofiltration is a treatment method that may be conducted in situ, with plants being grown directly in the contaminated water body. - It is a relatively inexpensive procedure with low capital costs -Operation costs are also low but depend on the type of contaminant. -This treatment method is also aesthetically pleasing and results in a decrease of water infiltration and leaching of contaminants. -After harvesting, the crop may be converted to biofuel briquette, a substitute for fossil fuel

__Disadvantages__ -Rhizofiltration is particularly effective in applications where low concentrations and large volumes of water are involved. Plants that are efficient at translocating metals to the shoots should not be used for rhizofiltration because more contaminated plant residue is produced. -Any contaminant that is below the rooting depth will not be extracted. -The plants used may not be able to grow in highly contaminated areas. -It can take years to reach regulatory levels. This results in long-term maintenance. -Most contaminated sites are polluted with many different kinds of contaminants. There can be a combination of metals and organics, in which treatment through rhizofiltration will not suffice. -Plants grown on polluted water and soils become a potential threat to human and animal health, and therefore, careful attention must be paid to the harvesting process and only non-fodder crop should be chosen for the rhizofiltration remediation method.

Rebecca D'Arcy