TABLE 7.
Comparison of conventional remediation technologies of heavy metal contaminated soils.
| Remediation technology | Advantages | Disadvantages |
|---|---|---|
| Excavation and soil capping (Physical) | -Effective | -High costs |
| -Short treatment time | -Loss of highly fertile surface soil | |
| -Heavy metals were removed permanently from the site | -Generation of dust and vapor during the excavation, which may cause air pollution | |
| -Groundwater controls may be needed | ||
| Soil washing sand flushing (Physical and chemical)< | -Effective | -Less effective when the soil contains high contents of silt, clay, and organic matter |
| -Can be done onsite by using portable equipment | -Wastewater generated needs to be treated and residue disposed of | |
| -The treated soils can be returned again to place | ||
| -Ability of metal recovery | ||
| -Highly applicable in coarse soils | ||
| Phytoremediation (Biological) | -Does not require expensive equipment and low costs | -Long time period required |
| -The plants can be easily monitored | -Remediation extends only to the depth of the root zone | |
| -The possibility of the recovery and re-use of valuable metals | -Not effective for highly contaminated soils | |
| -Climatic conditions are limiting factors | ||
| -Slow growth and low biomass require a long-term commitment | ||
| Stabilization/solidification (Chemical) | -Low costs | -Depth of contaminants may limit some types of application processes |
| -Time to complete the remediation is relatively short | -The solidified material may affect future uses of soil | |
| -Treatment needs to be renewed periodically |
Data obtained from Behm et al. (1997); Mulligan et al. (2001); Khalid et al. (2017).