190
A. K. Thakur and M. Kumar
any equipment can use at the particular site. The later factor includes the presence of
undersurface lithology that may cause the hindrances later, e.g., rocks and sediments.
8.5 The Software Involved in the Design of PRBs
As the numerical simulations play a most important role in determining the fate and
transport of the contaminants, software like MODFLOW, FE FLOW are important
so that the places of installation of injection and extraction wells can be selected. The
PRB once placed in between the groundwater flows, goes through several issues like
formation of metal hydroxides and carbonates precipitates, which ends up filling
the pore and in turn decreases the hydraulic conductivity. To remove this kind of
problems, we need more numerical software-based approaches which can help us
with the modeling of reactions occurring inside PRB and determinable mass balance
equations (Courcelles et al. 2011). Software programs like PHREEQC (Parkhurst
and Appelo 1999), ORCHESTRA (Meeussen 2003), MINTEQ (KTH, Dept. of Land
and Water Resources Engineering 2010), TOUGHREACT (Xu et al. 2004), CHESS
(L’Assistant Informatique per Chimistes et Ingénieurs 2010), PHT3D (Prommer et al.
2003) help one in replicating the complex chemical reactions.
All these simulation-based softwares in Table (8.3) are user-friendly and are
used according to the data management and outputs are needed, i.e., numerically
or graphically.
8.6 Design of PRBs
The foremost design when PRB is ever talked about comes out to be continuous
and funnel and gate system. (Pérez et al. 2018) analyzed the performance of two
differently designed permeable barriers for zinc and sulfate remediation. It uses
the two stainless sheets of steel reactors with a volume of 2.1 L volume, one for
homogeneous substrate and other for diffusive exchange. The first one contains a
mixture of all the materials, and the later one contains two layers namely reactive
and conductive (sand). Reactive materials used were (i) pine compost (439.8 g) (ii)
anaerobic sludge (54.98 g) (iii) nZVI (54.98 g) (iv) sand (0.5–5 mm, 2316.19 g) (v)
gypsum (23.37 g). The change in concentration of Zn was 65.5–0.01 ppm in 60 days.
Permeable reactive barrier wells are the new innovative design of PRBs which we
can implement for the remediation of VOCs in the low permeability aquifers (Bekel
et al. 2019).
A series of total 12 wells, each in the category of extraction wells (1.5 m) and
re-injection wells (1.2 m), were installed along the gradient of the plume. The depth
of these wells was 15–16 m. The wells were constructed using rig fitted with 1.2
and 1.5 m augers. The PRB materials were filled after a UPVC raiser was placed
A. K. Thakur and M. Kumar
any equipment can use at the particular site. The later factor includes the presence of
undersurface lithology that may cause the hindrances later, e.g., rocks and sediments.
8.5 The Software Involved in the Design of PRBs
As the numerical simulations play a most important role in determining the fate and
transport of the contaminants, software like MODFLOW, FE FLOW are important
so that the places of installation of injection and extraction wells can be selected. The
PRB once placed in between the groundwater flows, goes through several issues like
formation of metal hydroxides and carbonates precipitates, which ends up filling
the pore and in turn decreases the hydraulic conductivity. To remove this kind of
problems, we need more numerical software-based approaches which can help us
with the modeling of reactions occurring inside PRB and determinable mass balance
equations (Courcelles et al. 2011). Software programs like PHREEQC (Parkhurst
and Appelo 1999), ORCHESTRA (Meeussen 2003), MINTEQ (KTH, Dept. of Land
and Water Resources Engineering 2010), TOUGHREACT (Xu et al. 2004), CHESS
(L’Assistant Informatique per Chimistes et Ingénieurs 2010), PHT3D (Prommer et al.
2003) help one in replicating the complex chemical reactions.
All these simulation-based softwares in Table (8.3) are user-friendly and are
used according to the data management and outputs are needed, i.e., numerically
or graphically.
8.6 Design of PRBs
The foremost design when PRB is ever talked about comes out to be continuous
and funnel and gate system. (Pérez et al. 2018) analyzed the performance of two
differently designed permeable barriers for zinc and sulfate remediation. It uses
the two stainless sheets of steel reactors with a volume of 2.1 L volume, one for
homogeneous substrate and other for diffusive exchange. The first one contains a
mixture of all the materials, and the later one contains two layers namely reactive
and conductive (sand). Reactive materials used were (i) pine compost (439.8 g) (ii)
anaerobic sludge (54.98 g) (iii) nZVI (54.98 g) (iv) sand (0.5–5 mm, 2316.19 g) (v)
gypsum (23.37 g). The change in concentration of Zn was 65.5–0.01 ppm in 60 days.
Permeable reactive barrier wells are the new innovative design of PRBs which we
can implement for the remediation of VOCs in the low permeability aquifers (Bekel
et al. 2019).
A series of total 12 wells, each in the category of extraction wells (1.5 m) and
re-injection wells (1.2 m), were installed along the gradient of the plume. The depth
of these wells was 15–16 m. The wells were constructed using rig fitted with 1.2
and 1.5 m augers. The PRB materials were filled after a UPVC raiser was placed