6.4 nZVI Application and System Installation
Pilot injection of nZVI was performed in November 2017. The packer injection was
put into wells B149, B150, B151, B152, and B157. Apart from these wells, nZVI
was visually observed also in well B148 during the injection, this confirmed a good
distribution of nanoparticles in the subsurface (and confirmed existence of preferential migration zones). 250 kg of NANOFER DC in total (NANO IRON, s.r.o., Czech
Republic) was injected into the subsurface in concentration of 10 g/L with a total
injected volume of 25 m
3 . Into each injection point, 5000 L of nZVI suspension was
injected. A reactive barrier (RB) of electrokinetically enhanced nanoscale zerovalent iron particles was created.
There were three separate polygons for DC application. Each polygon had its own
power supply.
• The first polygon consisted of one anode (B149) and one cathode (B148);
• The second consisted of two anodes (B150, B158) and one cathode (B152);
• And the third polygon consisted also of two anodes (B151, B157) and one
cathode (B156).
All electrodes were permanently installed in the above-mentioned wells,
connected by copper wiring to the DC units. The wire-connected wells with the
DC units on the ground were protected by plastic cover. The DC units had their own
kWh counters with automatized logging and saved the data throughout the DC
application.
6.5 Results
6.5.1 Physicochemical Parameters of Groundwater
As there were another two nZVI injections performed in the past, the groundwater of
the Aargau site was in reductive conditions even before the current in situ injection.
However, the nZVI application intensified the reductive conditions in the groundwater—the redox potential decreased in cased wells from À200 mV (average in
October 2017) to À400 mV (average in October 2018). Dissolved oxygen decreased
significantly in all monitoring points until May or July 2018 (Fig. 6.7).
6.5.2 Contamination
The courses of contamination concentrations in the inflow area of RB are
documented in Fig. 6.8. This zone is the place where contaminated water enters
the pilot test area. The increases in the concentration of particular contaminants are
6 Field Study II: Pilot Application of nZVI/DC-Combined Methods at Aargau Site
111
Pilot injection of nZVI was performed in November 2017. The packer injection was
put into wells B149, B150, B151, B152, and B157. Apart from these wells, nZVI
was visually observed also in well B148 during the injection, this confirmed a good
distribution of nanoparticles in the subsurface (and confirmed existence of preferential migration zones). 250 kg of NANOFER DC in total (NANO IRON, s.r.o., Czech
Republic) was injected into the subsurface in concentration of 10 g/L with a total
injected volume of 25 m
3 . Into each injection point, 5000 L of nZVI suspension was
injected. A reactive barrier (RB) of electrokinetically enhanced nanoscale zerovalent iron particles was created.
There were three separate polygons for DC application. Each polygon had its own
power supply.
• The first polygon consisted of one anode (B149) and one cathode (B148);
• The second consisted of two anodes (B150, B158) and one cathode (B152);
• And the third polygon consisted also of two anodes (B151, B157) and one
cathode (B156).
All electrodes were permanently installed in the above-mentioned wells,
connected by copper wiring to the DC units. The wire-connected wells with the
DC units on the ground were protected by plastic cover. The DC units had their own
kWh counters with automatized logging and saved the data throughout the DC
application.
6.5 Results
6.5.1 Physicochemical Parameters of Groundwater
As there were another two nZVI injections performed in the past, the groundwater of
the Aargau site was in reductive conditions even before the current in situ injection.
However, the nZVI application intensified the reductive conditions in the groundwater—the redox potential decreased in cased wells from À200 mV (average in
October 2017) to À400 mV (average in October 2018). Dissolved oxygen decreased
significantly in all monitoring points until May or July 2018 (Fig. 6.7).
6.5.2 Contamination
The courses of contamination concentrations in the inflow area of RB are
documented in Fig. 6.8. This zone is the place where contaminated water enters
the pilot test area. The increases in the concentration of particular contaminants are
6 Field Study II: Pilot Application of nZVI/DC-Combined Methods at Aargau Site
111