(Vidali 2001). Now, scientists from all over the world have started to put their energy
to select or search new organism with more biodegradation ability for a number of
pollutants from different environmental locations (Kumar et al. 2011). On the basis
of applicability, bioremediation also can be categorized ex situ and in situ depending
upon the experimental process involved.
In situ Biodegradation It is a type of bioremediation in which nutrients and oxygen
are supplied into the contaminated site in the form of aqueous solution and degradation of organic contaminants is stimulated by native bacteria. This process is best
applicable in case of polluted groundwater and soil.
(A) Biosparging
In this process, concentration of groundwater oxygen is increased by injecting
pressurized air in the water, and contaminants are degraded biologically by native
microorganisms. The injected air increases the contact between groundwater and soil
so that saturated zone gets mixed. The requirement of less capital input in construction of the air injection system makes this process more flexible.
(B) Bioventing
It is the most commonly used in situ method which involves air supply with less
flow rate than biosparging. Here, the nutrients and necessary oxygen are provided to
indigenous bacteria through wells to stimulate biodegradation and minimize the
chance of release of volatile contaminants into the environment. This process is best
used for treatment of contaminants deep below the surface
(C) Bioaugmentation
It is the addition of potential microorganisms to the contaminated site with better
degradation ability. The organism may be indigenous or exogenous.
Ex situ Bioremediation This technique involves the physical removal or excavation
of polluted soil from a location. It involves:
(D) Land Farming
It is a very simple process which involves excavation of contaminated soil and
spreading over a bed followed by periodical turning for complete degradation of
contaminants by indigenous microorganisms through aerobic degradation. Advantage with this process is its reduced monitoring and maintenance cost, whereas
limitation to treat superficial 10–35 cm of soil is the main drawback of this process.
(E) Composting
A rich microbial population for biodegradation of pollutants with a characteristic
temperature of compost can be achieved by the mixing of contaminated soil with
nonhazardous organic contents like agricultural wastes or manure. These organic
contents support the growth or survivability of microorganisms which degrade the
pollutants.
17 Plant-Microbe Interactions for Bioremediation and Phytoremediation of. . .
423
to select or search new organism with more biodegradation ability for a number of
pollutants from different environmental locations (Kumar et al. 2011). On the basis
of applicability, bioremediation also can be categorized ex situ and in situ depending
upon the experimental process involved.
In situ Biodegradation It is a type of bioremediation in which nutrients and oxygen
are supplied into the contaminated site in the form of aqueous solution and degradation of organic contaminants is stimulated by native bacteria. This process is best
applicable in case of polluted groundwater and soil.
(A) Biosparging
In this process, concentration of groundwater oxygen is increased by injecting
pressurized air in the water, and contaminants are degraded biologically by native
microorganisms. The injected air increases the contact between groundwater and soil
so that saturated zone gets mixed. The requirement of less capital input in construction of the air injection system makes this process more flexible.
(B) Bioventing
It is the most commonly used in situ method which involves air supply with less
flow rate than biosparging. Here, the nutrients and necessary oxygen are provided to
indigenous bacteria through wells to stimulate biodegradation and minimize the
chance of release of volatile contaminants into the environment. This process is best
used for treatment of contaminants deep below the surface
(C) Bioaugmentation
It is the addition of potential microorganisms to the contaminated site with better
degradation ability. The organism may be indigenous or exogenous.
Ex situ Bioremediation This technique involves the physical removal or excavation
of polluted soil from a location. It involves:
(D) Land Farming
It is a very simple process which involves excavation of contaminated soil and
spreading over a bed followed by periodical turning for complete degradation of
contaminants by indigenous microorganisms through aerobic degradation. Advantage with this process is its reduced monitoring and maintenance cost, whereas
limitation to treat superficial 10–35 cm of soil is the main drawback of this process.
(E) Composting
A rich microbial population for biodegradation of pollutants with a characteristic
temperature of compost can be achieved by the mixing of contaminated soil with
nonhazardous organic contents like agricultural wastes or manure. These organic
contents support the growth or survivability of microorganisms which degrade the
pollutants.
17 Plant-Microbe Interactions for Bioremediation and Phytoremediation of. . .
423