Mode of Bioremediation





In situ

Biosparging Bioventing


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]


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]


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]