Bioremediation Technology: A Greener and Sustainable Approach for Restoration of Environmental Pollution - Applied Environmental Biotechnology: Present Scenario and Future Trends - page 7

Fig. 1.2 Ex-situ bioreme-
diation technique

Fig. 1.3 Bioremedia-
tion treatment strategies
in bioreactor. (Source:
Biotechnology in Medicine
and Agriculture Principles
and Practices)

1.6.2 In situ Bioremediation

ent. Bioventing supplies air to an unsaturated
soil zone through the installation of a well(s)
connected to associated pumps and blowers that
draw a vacuum on the soil. Air sparging involves
the injection of air into the saturated zone of a
contaminated soil.
It has long been recognized that microorgan-
isms have distinct and unique roles in the de-
toxification of polluted soil environments and,
in recent years, this process has been termed as
bioremediation or bioreclamation. The role of
microorganisms and their limitations for biore-
mediation must be better understood so that they
can be more efficiently utilized. Application of
the principles of microbial ecology will improve

With in situ techniques, the soil and associated
ground water is treated in place without excava-
tion, while it is excavated prior to treatment with
ex situ applications. Pump-and-treat systems,
which are applied to saturated-zone remediation,
involve the removal, treatment, and return of as-
sociated water from a contaminated soil zone.
The returned water is supplemented with nutri-
ents and saturated with oxygen. Percolation con-
sists of applying water, containing nutrients and
possibly a microbial inoculum, to the surface of
a contaminated area and allowing it to filter into
the soil and mix with the groundwater, if pres-