identified: (1) define, at laboratory scale, the operating conditions for the process
field application, (2) determine performances, (3) draw up the list of the equipment
and the technical conditions of in situ implementation, and (4) perform a complete
assessment of processes application.
A multiscale approach was thus used during development of the technology,
ranging from bench-scale laboratory tests using batches and columns as well as
model molecules to full-scale on-site treatability tests. Each successive scale experiment allowed the identification of the effects related to each scale; it also enabled
better design of the next larger scale experiment.
RCDC demonstration was performed in Néry-Saintines, 60, Oise, France, a large
polluted area of more than 1 km². It is an old quarry, used as illegal waste deposit
before 1978. The contaminated site was carefully selected because it presented a
well-documented pollution in a sandy aquifer of Cuisian period with a majority of
COCs and their metabolites provided by analyses since 1980. The use of state-ofthe-art database led us to design and implement the pilot (50 m width  50 m length
 22-23 m depth). Data provided by new physical and chemical monitoring in situ
allowed to better understand the three-dimensional dynamics of the chlorinated
solvent plume in the selected zone as well as to shed light on natural attenuation.
This approach allowed to evaluate the efficiency of the three defined emerging in situ
RCDC process.
6.5.1 Laboratory Experiments
For laboratory experiments, performed by using bench-scale laboratory tests—
mainly batches and columns—PCE was chosen as the target compound as it is one
of the most widespread chlorinated pollutants in groundwater.
First, batch experiments were carried out in tightly closed cells to study the
feasibility of RDC for PCE. Tests were carried out using sodium dithionite (Silex
International, Engis, Belgium) and nZVI particles, NANOFER 25 and NANOFER
25S (aqueous suspension of nZVI particles from NANO IRON s.r.o., Rajhrad,
Czech Republic), while varying operating parameters: nature and contents of
reagents, temperature (from 12 to 25
C), concentrations in pollutants, reagent/
pollutant molar ratios, treatment duration, physical and chemical parameters.
Columns experiments were then conducted in designed Kynar
® columns
(Fig. 6.6, height of 50 cm; diameter of 15 cm) fully equipped with sophisticated
systems for nondestructive monitoring of time changing physical parameters and
chemical compositions (Fig. 6.7). The entire system—filled with reference sand
from Fontainebleau, France, and with Cuisian sand from the selected polluted site—
was placed in air-conditioned cupboard under different operating conditions. Temperature, pH, ORP, conductivity, and dissolved oxygen in the column were monitored. Gas chromatography (GC) was used to monitor PCE and its degradation
products migration and dispersion over the entire columns. Ion chromatography
(IC) was used for the quantitation of Cl
À in the column effluent to correlate RCDC.
6 In Situ Chemical Reduction of Chlorinated Organic Compounds
341
field application, (2) determine performances, (3) draw up the list of the equipment
and the technical conditions of in situ implementation, and (4) perform a complete
assessment of processes application.
A multiscale approach was thus used during development of the technology,
ranging from bench-scale laboratory tests using batches and columns as well as
model molecules to full-scale on-site treatability tests. Each successive scale experiment allowed the identification of the effects related to each scale; it also enabled
better design of the next larger scale experiment.
RCDC demonstration was performed in Néry-Saintines, 60, Oise, France, a large
polluted area of more than 1 km². It is an old quarry, used as illegal waste deposit
before 1978. The contaminated site was carefully selected because it presented a
well-documented pollution in a sandy aquifer of Cuisian period with a majority of
COCs and their metabolites provided by analyses since 1980. The use of state-ofthe-art database led us to design and implement the pilot (50 m width  50 m length
 22-23 m depth). Data provided by new physical and chemical monitoring in situ
allowed to better understand the three-dimensional dynamics of the chlorinated
solvent plume in the selected zone as well as to shed light on natural attenuation.
This approach allowed to evaluate the efficiency of the three defined emerging in situ
RCDC process.
6.5.1 Laboratory Experiments
For laboratory experiments, performed by using bench-scale laboratory tests—
mainly batches and columns—PCE was chosen as the target compound as it is one
of the most widespread chlorinated pollutants in groundwater.
First, batch experiments were carried out in tightly closed cells to study the
feasibility of RDC for PCE. Tests were carried out using sodium dithionite (Silex
International, Engis, Belgium) and nZVI particles, NANOFER 25 and NANOFER
25S (aqueous suspension of nZVI particles from NANO IRON s.r.o., Rajhrad,
Czech Republic), while varying operating parameters: nature and contents of
reagents, temperature (from 12 to 25
C), concentrations in pollutants, reagent/
pollutant molar ratios, treatment duration, physical and chemical parameters.
Columns experiments were then conducted in designed Kynar
® columns
(Fig. 6.6, height of 50 cm; diameter of 15 cm) fully equipped with sophisticated
systems for nondestructive monitoring of time changing physical parameters and
chemical compositions (Fig. 6.7). The entire system—filled with reference sand
from Fontainebleau, France, and with Cuisian sand from the selected polluted site—
was placed in air-conditioned cupboard under different operating conditions. Temperature, pH, ORP, conductivity, and dissolved oxygen in the column were monitored. Gas chromatography (GC) was used to monitor PCE and its degradation
products migration and dispersion over the entire columns. Ion chromatography
(IC) was used for the quantitation of Cl
À in the column effluent to correlate RCDC.
6 In Situ Chemical Reduction of Chlorinated Organic Compounds
341