Bioslurping
Bioslurping combines soil vapor extraction, bioventing, and vacuum-enhanced
pumping to treat groundwater and soil via indirect preparing of O 2 and stimulation
of biodegradation. The method is not appropriate to treat low permeable soil;
however, it is cost-effective because of lesser content of groundwater after operation,
so the costs of storage, treatment, and disposal are minimized (Gidarakos and
Aivalioti 2007). The major challenges of this in situ technique (Philp and Atlas,
2005) are the fluctuating water table and the need to establish a vacuum on a deep
and high-permeable site.
Ex situ bioremediation includes land farming, windrows, bioreactors, and
biopiles.
Land Farming
One of the simplest bioremediation techniques with less equipment and low cost
requirement is land farming. This can be an ex situ or in situ technique depending on
the site of treatment. Pollutant depth plays a major role in whether the method carried
out is ex situ or in situ. In this method, the contaminated soil is commonly excavated
and/or tilled; however, the kind of bioremediation is obviously specified by the site
of remediation. Whenever the excavated contaminated soil is remediated on-site, it is
classified as in situ and in other cases it is ex situ. It has been showed that
bioremediation can proceed without excavation if a contaminant lies <1 m below
the ground surface, while contaminant lying >1.7 m must be carried to ground
surface to enhance efficiency of biotreatment (Nikolopoulou et al. 2013). Land
farming system can be used in any climate and location. The method is very easy
to implement and design, can treat a large volume of contaminated soils with the
minimum of environmental impact and required energy as well as low capital input
(Maila and Colete 2004). Some limitations of the technique are big operating space,
decrease in the activities of microbes because of undesirable environmental situations, further cost because of excavation, as well as decreased efficacy in inorganic
contaminant removal (Maila and Colete 2004). Land farming technique is not
appropriate to treat soil contaminated with toxic volatiles because of its mechanism
of contaminant removal (volatilization) and design and especially in hightemperature (tropical) climate regions. The limitations are that the farming-based
biotreatment can be time-consuming with less success in comparison with other ex
situ bioremediation methods.
Windrows
It is based on turning of piled contaminated soil periodically, in order to enhance
biotreatment by improving the degradation activities of native microorganisms and
transient hydrocarbonoclastic bacteria. The periodic turning and addition of water
12 Remediation of Pollution by Oil Spills
475
Bioslurping combines soil vapor extraction, bioventing, and vacuum-enhanced
pumping to treat groundwater and soil via indirect preparing of O 2 and stimulation
of biodegradation. The method is not appropriate to treat low permeable soil;
however, it is cost-effective because of lesser content of groundwater after operation,
so the costs of storage, treatment, and disposal are minimized (Gidarakos and
Aivalioti 2007). The major challenges of this in situ technique (Philp and Atlas,
2005) are the fluctuating water table and the need to establish a vacuum on a deep
and high-permeable site.
Ex situ bioremediation includes land farming, windrows, bioreactors, and
biopiles.
Land Farming
One of the simplest bioremediation techniques with less equipment and low cost
requirement is land farming. This can be an ex situ or in situ technique depending on
the site of treatment. Pollutant depth plays a major role in whether the method carried
out is ex situ or in situ. In this method, the contaminated soil is commonly excavated
and/or tilled; however, the kind of bioremediation is obviously specified by the site
of remediation. Whenever the excavated contaminated soil is remediated on-site, it is
classified as in situ and in other cases it is ex situ. It has been showed that
bioremediation can proceed without excavation if a contaminant lies <1 m below
the ground surface, while contaminant lying >1.7 m must be carried to ground
surface to enhance efficiency of biotreatment (Nikolopoulou et al. 2013). Land
farming system can be used in any climate and location. The method is very easy
to implement and design, can treat a large volume of contaminated soils with the
minimum of environmental impact and required energy as well as low capital input
(Maila and Colete 2004). Some limitations of the technique are big operating space,
decrease in the activities of microbes because of undesirable environmental situations, further cost because of excavation, as well as decreased efficacy in inorganic
contaminant removal (Maila and Colete 2004). Land farming technique is not
appropriate to treat soil contaminated with toxic volatiles because of its mechanism
of contaminant removal (volatilization) and design and especially in hightemperature (tropical) climate regions. The limitations are that the farming-based
biotreatment can be time-consuming with less success in comparison with other ex
situ bioremediation methods.
Windrows
It is based on turning of piled contaminated soil periodically, in order to enhance
biotreatment by improving the degradation activities of native microorganisms and
transient hydrocarbonoclastic bacteria. The periodic turning and addition of water
12 Remediation of Pollution by Oil Spills
475