(F) Biopiles
A technique consisting property of both composting and land farming where cells
are constructed to aerate the composted pile. Here, physical loss such as volatilization and leaching of contaminant is reduced.
(G) Bioreactors
In this ex situ technology of removal of pollutants, water and contaminated soil
are treated in aqueous reactors or slurry reactors. Here, polluted materials are more
manageable than in situ methods. The main disadvantage of this process is that it
requires pretreatment like washing of soil.
3.2.1.1 Advantage of Bioremediation
It is the most natural and publically accepted process to treat pollutants. The residue
produced after the practices is harmless which may include bacterial cells, water, and
carbon dioxide.
It is less expensive and possesses almost complete degradation of pollutants.
3.2.1.2 Disadvantage of Bioremediation
The main disadvantage of this technology is the limitation of treatment of only
biodegradable materials. Sometimes the bacterial metabolic process involved in the
process is highly specific; hence a controlled environment is required for the
successful degradation of contaminants. The longer time consumption and
pretreatment of target media like soil contribute to the disadvantages of the process.
3.2.2 Phytoremediation
Plants are natural filter and metabolize naturally generated substances, and therefore, the use of plants for the removal of contaminants in water and soil is the
emerging technology known as phytoremediation (EPA 1999, 2000; Raskin and
Ensley 2000; Chandra et al. 2015; Saxena et al. 2019). This technology is further
categorized in six different types of techniques (Table 17.2) which are classified on
the basis of types of contaminants: phytovolatilization, phytotransformation,
phytostabilization, rhizofiltration, rhizodegradation, and phytoextraction.
3.2.2.1 Phytoextraction or Phytoaccumulation
In this process, accumulation of contaminants in plant takes place in the root system
and shoot or leaves present above the ground which ultimately saves economy
424
A. Mishra et al.
A technique consisting property of both composting and land farming where cells
are constructed to aerate the composted pile. Here, physical loss such as volatilization and leaching of contaminant is reduced.
(G) Bioreactors
In this ex situ technology of removal of pollutants, water and contaminated soil
are treated in aqueous reactors or slurry reactors. Here, polluted materials are more
manageable than in situ methods. The main disadvantage of this process is that it
requires pretreatment like washing of soil.
3.2.1.1 Advantage of Bioremediation
It is the most natural and publically accepted process to treat pollutants. The residue
produced after the practices is harmless which may include bacterial cells, water, and
carbon dioxide.
It is less expensive and possesses almost complete degradation of pollutants.
3.2.1.2 Disadvantage of Bioremediation
The main disadvantage of this technology is the limitation of treatment of only
biodegradable materials. Sometimes the bacterial metabolic process involved in the
process is highly specific; hence a controlled environment is required for the
successful degradation of contaminants. The longer time consumption and
pretreatment of target media like soil contribute to the disadvantages of the process.
3.2.2 Phytoremediation
Plants are natural filter and metabolize naturally generated substances, and therefore, the use of plants for the removal of contaminants in water and soil is the
emerging technology known as phytoremediation (EPA 1999, 2000; Raskin and
Ensley 2000; Chandra et al. 2015; Saxena et al. 2019). This technology is further
categorized in six different types of techniques (Table 17.2) which are classified on
the basis of types of contaminants: phytovolatilization, phytotransformation,
phytostabilization, rhizofiltration, rhizodegradation, and phytoextraction.
3.2.2.1 Phytoextraction or Phytoaccumulation
In this process, accumulation of contaminants in plant takes place in the root system
and shoot or leaves present above the ground which ultimately saves economy
424
A. Mishra et al.