8 Reappraisal of Permeable Reactive Barrier as a Sustainable …
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8.3 Groundwater remediation technologies
Groundwater remediation has always proved to be a costly affair. The remediation
technologies are mainly divided into three main categories namely (Hashim et al.
2011)
Chemical—Reduction, chemical flushing, in situ chemical fixation
Biological—Biological activity, bio-sorption, enhanced bio-restoration
Physical–chemical processes—PRBs, electro-kinetics, adsorptions.
The major processes involved in the remediation of groundwater involved from
the last few decades are (Vallero 2011)
Pump and Treat: It employs more than one pumping wells, and the contaminants
are cleaned up using physical or biological mechanisms. Not use in the case of
low permeable aquifers (Zhang).
Air Stripping: It transfers all the volatile compounds from water to air.
Air Sparging: Here, the air is pumped into the water below to aerate it.
Bioremediation: It uses lively microorganisms to degrade or render the toxic
materials harmless.
Filter through GAC: These granular activated carbons (GACs) help in the
containment of the contaminants.
Natural Attenuation: It is the secondary form of bioremediation. The contaminants
degrade over time with the help of microbes present instead of employing some
pieces of machinery.
Bio-filtration: It is generally used to treat vapor-phase pollutants. It has a medium
which is porous and contains microbes inside of it.
Adsorptions: It is most applicable for organic compounds but has also shown
promising results for inorganic ones. Both the type of adsorptions, i.e., physical and chemical arises due to the electrostatic interactions (Muralikrishna and
Manickam 2017).
The chemical treatment mainly involves detoxifying the contaminant by redox
reactions or some time the only lone process of reduction or oxidation occurs (Evanko
and Dzombak 1997). The chemical in situ application of permeable reactive barrier
(PRB) has gained a lot of interest due to the low operational cost, media longevity and
its hydraulic performance. PRB uses the hydraulic gradient (natural or induced) for
remediating the contaminated groundwater, and the upgradient contaminated water
gets decontaminated after reaching down gradient (Starr and Cherry 1994).
8.4 Permeable Reactive Barriers (PRBs)
Permeable reactive barrier has been defined as a trench filled with a certain amount of
reactive material to remediate the contaminated groundwater contained in the aquifers
187
8.3 Groundwater remediation technologies
Groundwater remediation has always proved to be a costly affair. The remediation
technologies are mainly divided into three main categories namely (Hashim et al.
2011)
Chemical—Reduction, chemical flushing, in situ chemical fixation
Biological—Biological activity, bio-sorption, enhanced bio-restoration
Physical–chemical processes—PRBs, electro-kinetics, adsorptions.
The major processes involved in the remediation of groundwater involved from
the last few decades are (Vallero 2011)
Pump and Treat: It employs more than one pumping wells, and the contaminants
are cleaned up using physical or biological mechanisms. Not use in the case of
low permeable aquifers (Zhang).
Air Stripping: It transfers all the volatile compounds from water to air.
Air Sparging: Here, the air is pumped into the water below to aerate it.
Bioremediation: It uses lively microorganisms to degrade or render the toxic
materials harmless.
Filter through GAC: These granular activated carbons (GACs) help in the
containment of the contaminants.
Natural Attenuation: It is the secondary form of bioremediation. The contaminants
degrade over time with the help of microbes present instead of employing some
pieces of machinery.
Bio-filtration: It is generally used to treat vapor-phase pollutants. It has a medium
which is porous and contains microbes inside of it.
Adsorptions: It is most applicable for organic compounds but has also shown
promising results for inorganic ones. Both the type of adsorptions, i.e., physical and chemical arises due to the electrostatic interactions (Muralikrishna and
Manickam 2017).
The chemical treatment mainly involves detoxifying the contaminant by redox
reactions or some time the only lone process of reduction or oxidation occurs (Evanko
and Dzombak 1997). The chemical in situ application of permeable reactive barrier
(PRB) has gained a lot of interest due to the low operational cost, media longevity and
its hydraulic performance. PRB uses the hydraulic gradient (natural or induced) for
remediating the contaminated groundwater, and the upgradient contaminated water
gets decontaminated after reaching down gradient (Starr and Cherry 1994).
8.4 Permeable Reactive Barriers (PRBs)
Permeable reactive barrier has been defined as a trench filled with a certain amount of
reactive material to remediate the contaminated groundwater contained in the aquifers