vegetation had a good evolution, and the H. rhamnoides seedlings had a massive
drainage, already providing a good cover for the waste dumps (Liu et al. 2018a, b).
4.6
The Role of Plants in Bioremediation
4.6.1 The Importance of Phytoremediation of Soils Contaminated
with Heavy Metals
Phytoremediation includes the use of plants to extract, seize, and detoxify pollutants.
This is an efficient, noninvasive, economically efficient, aesthetically pleasing, and
socially acceptable method for remedying polluted areas (Sarma et al. 2021).
The major benefits reported for phytoremediation compared to traditional remediation technologies include the following: a possibility to generate less secondary
residues, a minimal degradation of the environment, an opportunity to leave the soil
in place and under conditions of use after treatment, have low design costs for the
candidate land for remediation, and a method requiring very little technique because
implementation requires little more than basic agricultural techniques.
Disadvantages include the following:
A long period of time required (several growing seasons).
A limited depth that can be applied (1.2 m for soil and 3 m for groundwater) because
the roots can effectively clean only a limited depth.
An opportunity for pollutants to enter the food chain through plant animal
consumption.
Operating characteristics and costs for a large-scale implementation have not yet
been fully evaluated.
Plant residue may require deposition as hazardous waste or requires additional
treatment.
Degradation by-products may be mobilized to groundwater or bioaccumulated in
animals.
If the concentration of the contaminants is too high, the plants may die.
Plant growth may be seasonal depending on location.
Climatic and hydrological conditions (e.g., floods, droughts) can restrict the growth
rate of the type of plant that can be used.
An area of the site may be modified to prevent floods or erosion; soil amendments,
including chelating agents, may be necessary to ease the uptake of pollutants by
plants by breaking the links between contaminants and soil particles.
The phytoextraction technique has a number of advantages that can make it more
attractive than other rehabilitation techniques: it reduces the volumes to be deposited
in the landfill (at the end of the process, the plants are burned, and so the amount of
ash is much smaller than the mass of contaminated soil ), saves energy (the process
of cleaning is based on solar energy), operates very simply, does not disturb visually
and is acceptable to public opinion, and is relatively easy to apply on extended
102
M. Butu et al.
drainage, already providing a good cover for the waste dumps (Liu et al. 2018a, b).
4.6
The Role of Plants in Bioremediation
4.6.1 The Importance of Phytoremediation of Soils Contaminated
with Heavy Metals
Phytoremediation includes the use of plants to extract, seize, and detoxify pollutants.
This is an efficient, noninvasive, economically efficient, aesthetically pleasing, and
socially acceptable method for remedying polluted areas (Sarma et al. 2021).
The major benefits reported for phytoremediation compared to traditional remediation technologies include the following: a possibility to generate less secondary
residues, a minimal degradation of the environment, an opportunity to leave the soil
in place and under conditions of use after treatment, have low design costs for the
candidate land for remediation, and a method requiring very little technique because
implementation requires little more than basic agricultural techniques.
Disadvantages include the following:
A long period of time required (several growing seasons).
A limited depth that can be applied (1.2 m for soil and 3 m for groundwater) because
the roots can effectively clean only a limited depth.
An opportunity for pollutants to enter the food chain through plant animal
consumption.
Operating characteristics and costs for a large-scale implementation have not yet
been fully evaluated.
Plant residue may require deposition as hazardous waste or requires additional
treatment.
Degradation by-products may be mobilized to groundwater or bioaccumulated in
animals.
If the concentration of the contaminants is too high, the plants may die.
Plant growth may be seasonal depending on location.
Climatic and hydrological conditions (e.g., floods, droughts) can restrict the growth
rate of the type of plant that can be used.
An area of the site may be modified to prevent floods or erosion; soil amendments,
including chelating agents, may be necessary to ease the uptake of pollutants by
plants by breaking the links between contaminants and soil particles.
The phytoextraction technique has a number of advantages that can make it more
attractive than other rehabilitation techniques: it reduces the volumes to be deposited
in the landfill (at the end of the process, the plants are burned, and so the amount of
ash is much smaller than the mass of contaminated soil ), saves energy (the process
of cleaning is based on solar energy), operates very simply, does not disturb visually
and is acceptable to public opinion, and is relatively easy to apply on extended
102
M. Butu et al.