Column experiments allowed to:
• Evaluate the applicability of the selected operating conditions similar to those
being encountered on the aquifers or soils
• Improve the understanding of reactant efficacy, and also their transformation and
persistence
• Model these flow-through systems (1D or 2D column setup) by numerical
modeling softwares (PHREEQC
®
and MARTHE
®
reactive transport
simulations)
Results also recommended the combination of geophysical measurements with
electroanalytical measurements to monitor RCDC process which is regarded as an
advantageous method for monitoring in situ remediation processes.
6.5.2 In Situ Implementation
6.5.2.1 The Large Area
Figure 6.8a shows the geographic location of the polluted site. It is a large area of
more than 1 km² composed of a network of 12 piezometers. The zone is constantly
fed (open system) and the pollution conveyed by the water table of Cuisian sand. A
conceptual scheme of the polluted site as a large area is given in Fig. 6.8b.
Before RCDC implementation, the physical and chemical parameters of the
groundwater of the polluted site (i.e., the Natural Attenuation Monitoring) were
investigated through two times scales and two-dimension scales:
• During 15 years (1999–2013) from several tens of piezometers (PZs) distributed
in a large area of more than 1 km². This preliminary work enabled to choose the
suitable location to deploy the RCDC pilot.
• During 6 months (July–December, 2014) locally, from 12 piezometers, sampled
at two depths (À10 and À20 m), in a smaller area (50 m  50 m) where the pilot
was installed.
The objective of this preliminary study was to (1) improve understanding on the
mechanisms and kinetics of natural attenuation process that have occurred in the
groundwater of this old polluted site, (2) evaluate if natural attenuation can or not be
perceived as an attractive option, and (3) compare the two processes, the natural
attenuation and the forthcoming RCDC.
For both large and small areas, the analytical methodology was composed of:
• Field measurements or analyses of the nonconservative parameters/species: pH,
ORP, temperature, conductivity, dissolved oxygen, and some species such as
chloride, bicarbonate, dissolved iron, sulfide (present in deeper sediments), sulfate, and phosphate ions
6 In Situ Chemical Reduction of Chlorinated Organic Compounds
343
• Evaluate the applicability of the selected operating conditions similar to those
being encountered on the aquifers or soils
• Improve the understanding of reactant efficacy, and also their transformation and
persistence
• Model these flow-through systems (1D or 2D column setup) by numerical
modeling softwares (PHREEQC
®
and MARTHE
®
reactive transport
simulations)
Results also recommended the combination of geophysical measurements with
electroanalytical measurements to monitor RCDC process which is regarded as an
advantageous method for monitoring in situ remediation processes.
6.5.2 In Situ Implementation
6.5.2.1 The Large Area
Figure 6.8a shows the geographic location of the polluted site. It is a large area of
more than 1 km² composed of a network of 12 piezometers. The zone is constantly
fed (open system) and the pollution conveyed by the water table of Cuisian sand. A
conceptual scheme of the polluted site as a large area is given in Fig. 6.8b.
Before RCDC implementation, the physical and chemical parameters of the
groundwater of the polluted site (i.e., the Natural Attenuation Monitoring) were
investigated through two times scales and two-dimension scales:
• During 15 years (1999–2013) from several tens of piezometers (PZs) distributed
in a large area of more than 1 km². This preliminary work enabled to choose the
suitable location to deploy the RCDC pilot.
• During 6 months (July–December, 2014) locally, from 12 piezometers, sampled
at two depths (À10 and À20 m), in a smaller area (50 m  50 m) where the pilot
was installed.
The objective of this preliminary study was to (1) improve understanding on the
mechanisms and kinetics of natural attenuation process that have occurred in the
groundwater of this old polluted site, (2) evaluate if natural attenuation can or not be
perceived as an attractive option, and (3) compare the two processes, the natural
attenuation and the forthcoming RCDC.
For both large and small areas, the analytical methodology was composed of:
• Field measurements or analyses of the nonconservative parameters/species: pH,
ORP, temperature, conductivity, dissolved oxygen, and some species such as
chloride, bicarbonate, dissolved iron, sulfide (present in deeper sediments), sulfate, and phosphate ions
6 In Situ Chemical Reduction of Chlorinated Organic Compounds
343