5.1.5 Biostimulation
Biostimulation involves the alteration in the environmental condition to stimulate the
native bacterial population capable to perform bioremediation. The process can be
done by adding various forms of rate-limiting nutrients and electron acceptors, such
as phosphorus, nitrogen, oxygen, or carbon.
5.1.6 Natural Attenuation
Natural attenuation comprises the processes that leads to reduction of the mass,
toxicity, mobility, or volume of pollutants without human intervention.
5.2 Ex Situ Techniques
The ex situ techniques involve excavating contaminated samples from selected
locations and transporting them to another location for processing (Ahmad et al.
2018). The factors that control off-site techniques include treatment costs, geographic location, type and depth of pollutants, and pollution levels (Azubuike
et al. 2016). Due to other parameters, i.e., soil excavation, the processing cost of
the ex situ technique may be much higher than the in situ technique.
5.2.1 Composting
Composting is the technique, in which nonhazardous organic materials such as
manure are added to contaminated soil. These organic materials support in developing the microbial population growth, thereby improving the temperature for
composting. The prepared compost bed has a variety of possibilities for bioremediation of pollutants using organic chelating agents, changing pH, redox potential, and
surfactant production.
5.2.2 Land Farming
Land farming technology is used to decontaminate the contaminated site by excavating the contaminate soil and spread on prepared beds, and farming is carried out
regularly until the pollutants are degraded. The main purpose of this technology is to
motivate the naturally degraded microbial diversity and promote the aerobic degradation of pollutants.
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R. K. Ravi and R. Y. Hiranmai
Biostimulation involves the alteration in the environmental condition to stimulate the
native bacterial population capable to perform bioremediation. The process can be
done by adding various forms of rate-limiting nutrients and electron acceptors, such
as phosphorus, nitrogen, oxygen, or carbon.
5.1.6 Natural Attenuation
Natural attenuation comprises the processes that leads to reduction of the mass,
toxicity, mobility, or volume of pollutants without human intervention.
5.2 Ex Situ Techniques
The ex situ techniques involve excavating contaminated samples from selected
locations and transporting them to another location for processing (Ahmad et al.
2018). The factors that control off-site techniques include treatment costs, geographic location, type and depth of pollutants, and pollution levels (Azubuike
et al. 2016). Due to other parameters, i.e., soil excavation, the processing cost of
the ex situ technique may be much higher than the in situ technique.
5.2.1 Composting
Composting is the technique, in which nonhazardous organic materials such as
manure are added to contaminated soil. These organic materials support in developing the microbial population growth, thereby improving the temperature for
composting. The prepared compost bed has a variety of possibilities for bioremediation of pollutants using organic chelating agents, changing pH, redox potential, and
surfactant production.
5.2.2 Land Farming
Land farming technology is used to decontaminate the contaminated site by excavating the contaminate soil and spread on prepared beds, and farming is carried out
regularly until the pollutants are degraded. The main purpose of this technology is to
motivate the naturally degraded microbial diversity and promote the aerobic degradation of pollutants.
160
R. K. Ravi and R. Y. Hiranmai