Mode of Bioremediation | Examples | Advantages/Effectiveness | Disadvantages | Ref. |
In situ | Biosparging Bioventing Bioaugmentation | Most Cost effective; Natural attenuation process; Relatively passive; Treats soil and water; | Extended treatment time; Monitoring difficulties; Environmental constraints; | [21] [24] |
Ex situ | Land farming Composting Biopiling | Low cost; Can be done on site; | Space requirement; Extended treatment time; Bioavailability limitation; | [24] [29] |
Phytoremediation | Phytoextraction Phytotransformation Phytodegradation Phytostabilisation Rhizoremediation | Cost of the phytoremediation lower than that of traditional processes both in-situ and ex-situ; Can be easily monitored; Uses naturally occurring organisms and preserves the natural state of the environment; | The toxicity and bioavailability of biodegradation products are not permanently known; Too high concentration of contaminants can result in plants death; | [50] [70] [71] |
Rhizoremediation | Exclusion Extrusion Accommodation Biotransformation Methylation Demethylation Desorption/adsorption of heavy metals | Uptake of metals in plant roots; Roots absorb Zn, Pb, Cd, As; Groundwater adsorb pollutants, mainly metals, from water and aqueous waste streams; | May require a longer period than other remedial approaches; Phytoremediation is limited to the depth that the plant roots can reach and to sites with low contaminants concentrations because concentrations that are too high can be toxic to plants; | [21] [72] [73] |
| Plant Growth promoting Rhizobacteria | resource acquisition including assimilation of N from atmosphere, protection of host plant from pathogenic microorganisms and heavy metals | [74] [75] |