bioremediation so it has also been combined with nanotechnology for the removal of
contaminants from the soil (Mehndiratta et al. 2013; Prasad and Aranda 2018).
15.3 Bioremediation as a Sustainable Method for Remediation
of Contaminants
Sustainable remediation approach has been described as a “treatment or a combination of treatments, which overall benefited humans and the surrounding living
organisms (Jonsson and Haller 2014). The use of bioremediation seems to be the
best alternative that involves microorganisms for resolving and eliminating
contaminants by various treatment strategies (Agwu and Kalu 2012; Abatenh et al.
2017). Bioremediation is the sustainable, profitable and environmentally friendly
approach for managing the polluted soils, sediments and groundwater (Banat et al.
2000; Kandelbauer and Guebitz 2005; Magan et al. 2010; Karigar and Rao 2011;
Kumar et al. 2011; Nawaz et al. 2011; Niti et al. 2013; Fernando et al. 2018).
Bioremediation utilizes the biological processes involving microbial metabolism and
several enzymes to remediate the toxic effluents produced from sewage, domestic
and industry into less toxic form (Kulkarni and Chaudhari 2007; Agwu and Kalu
2012; Gillespie and Philp 2013; Niti et al. 2013; Jonsson and Haller 2014; Alkorta
et al. 2017; Shah 2017; Prasad and Aranda 2018). Bioremediation approaches focus
on utilizing the metabolic capacity to attenuate the harmful effects of the
contaminants through the following methods (Pandey et al. 2009):
(i) detoxification of toxic compounds into less toxic form, (ii) complete degradation
of contaminants and (iii) Immobilization of the contaminant.
Bioremediation can be operated both in situ and ex situ depending on the nature
of contaminants and site conditions (Pandey et al. 2009; Agwu and Kalu 2012;
Thakare et al. 2021):
15.3.1 In Situ Bioremediation
“In situ bioremediation” involves the remediation of contaminants under natural
conditions of the environment by the use of the metabolic potential of microbes,
without excavating or physical removal of contaminated soils or water from its
original location (Sasikumar and Papinazath 2003; Kulkarni and Chaudhari 2007).
Its cost-effectiveness and least disturbances due to no need of transport of pollutants
from one site to another make it the most attractive alternative. Soil depth is the
major restriction, thus rendering its use in a few cases (Niti et al. 2013; Shah 2017).
Chemotaxis is a significant process in in situ bioremediation approaches, as
microbes with their metabolic chemotactic abilities may shift into areas affected
with pollutants. With the enhancement of chemotactic capabilities of microbial cells,
in situ bioremediation will be a secure method in future to biodegrade the hazardous
waste (Sasikumar and Papinazath 2003; Niti et al. 2013). In situ bioremediation has
several advantages in comparison with conventional approaches; for instance, it is
426
G. Kaur et al.
contaminants from the soil (Mehndiratta et al. 2013; Prasad and Aranda 2018).
15.3 Bioremediation as a Sustainable Method for Remediation
of Contaminants
Sustainable remediation approach has been described as a “treatment or a combination of treatments, which overall benefited humans and the surrounding living
organisms (Jonsson and Haller 2014). The use of bioremediation seems to be the
best alternative that involves microorganisms for resolving and eliminating
contaminants by various treatment strategies (Agwu and Kalu 2012; Abatenh et al.
2017). Bioremediation is the sustainable, profitable and environmentally friendly
approach for managing the polluted soils, sediments and groundwater (Banat et al.
2000; Kandelbauer and Guebitz 2005; Magan et al. 2010; Karigar and Rao 2011;
Kumar et al. 2011; Nawaz et al. 2011; Niti et al. 2013; Fernando et al. 2018).
Bioremediation utilizes the biological processes involving microbial metabolism and
several enzymes to remediate the toxic effluents produced from sewage, domestic
and industry into less toxic form (Kulkarni and Chaudhari 2007; Agwu and Kalu
2012; Gillespie and Philp 2013; Niti et al. 2013; Jonsson and Haller 2014; Alkorta
et al. 2017; Shah 2017; Prasad and Aranda 2018). Bioremediation approaches focus
on utilizing the metabolic capacity to attenuate the harmful effects of the
contaminants through the following methods (Pandey et al. 2009):
(i) detoxification of toxic compounds into less toxic form, (ii) complete degradation
of contaminants and (iii) Immobilization of the contaminant.
Bioremediation can be operated both in situ and ex situ depending on the nature
of contaminants and site conditions (Pandey et al. 2009; Agwu and Kalu 2012;
Thakare et al. 2021):
15.3.1 In Situ Bioremediation
“In situ bioremediation” involves the remediation of contaminants under natural
conditions of the environment by the use of the metabolic potential of microbes,
without excavating or physical removal of contaminated soils or water from its
original location (Sasikumar and Papinazath 2003; Kulkarni and Chaudhari 2007).
Its cost-effectiveness and least disturbances due to no need of transport of pollutants
from one site to another make it the most attractive alternative. Soil depth is the
major restriction, thus rendering its use in a few cases (Niti et al. 2013; Shah 2017).
Chemotaxis is a significant process in in situ bioremediation approaches, as
microbes with their metabolic chemotactic abilities may shift into areas affected
with pollutants. With the enhancement of chemotactic capabilities of microbial cells,
in situ bioremediation will be a secure method in future to biodegrade the hazardous
waste (Sasikumar and Papinazath 2003; Niti et al. 2013). In situ bioremediation has
several advantages in comparison with conventional approaches; for instance, it is
426
G. Kaur et al.