of this knowledge, the number of successful full-scale applications has been increasing for the past 15 years and the degradation effectivity of nZVI has also been
confirmed by in situ applications (Mueller et al. 2012). Recent studies from the
contaminated sites where nZVI was applied also reported its stimulation effect on
selected microbial species and its potential for the combination of nanoremediation
and bioremediation (Němeček et al. 2014, 2015, 2016). This chapter is summarizing
two pilot-scale experiments done in the Czech Republic during which nZVI and
whey as a microbial substrate were successfully applied for geofixation of Cr
(VI) and dechlorination of chlorinated ethenes.
20.2 Locality 1
20.2.1 Sampling and Site Monitoring
The first test site is situated at the Kortan site in the north of the Czech Republic
where a leather processing plant was set up in the past. Up to the 1990s, the factory
used potassium dichromate for leather tanning whence the contamination with Cr
(VI) comes. The current levels of Cr(VI) in groundwater are close to 3 mg/L. The
aquifer is surrounded by a mixture of Quaternary sands and gravels with clayey
admixture. The saturated zone of the aquifer is approximately 5 m thick; the
groundwater table fluctuates at 4.5–5.5 m below the surface of the ground and the
flow velocity staggers from 0.2 to 2 m/day. Finally, the groundwater discharges to a
nearby river located approximately 500 m from the site. The physicochemical
parameters of the groundwater reach values of pH 5.4, total organic carbon
˂1.5 mg/L, the total dissolved solids ˂0.3 g/L, and a high oxidation-reduction
potential (450 to 550 mV).
The site monitoring was carried out by 19 sampling rounds during both phases,
whereas groundwater samples of each round were collected from seven different
wells. Before the pilot test, nine wells were drilled: three nZVI injection wells
(PV-209, PV-213, and PV-215), three downgradient (PV-214, PV-216, PV-217)
and one upgradient monitoring well (PV-212), which served as a reference. Besides
the seven main wells, another two downgradient monitoring wells (PV-201 and
PV-210) were sampled for additional analysis. The positions of the monitoring and
the injection wells are displayed in Fig. 20.1.
20.2.2 Pilot Application of nZVI and Subsequential Whey
Injection
The pilot test at the Kortan site consisted of two phases—abiotic and biotic. In
summer 2012, during the first (abiotic) phase of the pilot test, 120 kg of nZVI
426
J. Semerád et al.
confirmed by in situ applications (Mueller et al. 2012). Recent studies from the
contaminated sites where nZVI was applied also reported its stimulation effect on
selected microbial species and its potential for the combination of nanoremediation
and bioremediation (Němeček et al. 2014, 2015, 2016). This chapter is summarizing
two pilot-scale experiments done in the Czech Republic during which nZVI and
whey as a microbial substrate were successfully applied for geofixation of Cr
(VI) and dechlorination of chlorinated ethenes.
20.2 Locality 1
20.2.1 Sampling and Site Monitoring
The first test site is situated at the Kortan site in the north of the Czech Republic
where a leather processing plant was set up in the past. Up to the 1990s, the factory
used potassium dichromate for leather tanning whence the contamination with Cr
(VI) comes. The current levels of Cr(VI) in groundwater are close to 3 mg/L. The
aquifer is surrounded by a mixture of Quaternary sands and gravels with clayey
admixture. The saturated zone of the aquifer is approximately 5 m thick; the
groundwater table fluctuates at 4.5–5.5 m below the surface of the ground and the
flow velocity staggers from 0.2 to 2 m/day. Finally, the groundwater discharges to a
nearby river located approximately 500 m from the site. The physicochemical
parameters of the groundwater reach values of pH 5.4, total organic carbon
˂1.5 mg/L, the total dissolved solids ˂0.3 g/L, and a high oxidation-reduction
potential (450 to 550 mV).
The site monitoring was carried out by 19 sampling rounds during both phases,
whereas groundwater samples of each round were collected from seven different
wells. Before the pilot test, nine wells were drilled: three nZVI injection wells
(PV-209, PV-213, and PV-215), three downgradient (PV-214, PV-216, PV-217)
and one upgradient monitoring well (PV-212), which served as a reference. Besides
the seven main wells, another two downgradient monitoring wells (PV-201 and
PV-210) were sampled for additional analysis. The positions of the monitoring and
the injection wells are displayed in Fig. 20.1.
20.2.2 Pilot Application of nZVI and Subsequential Whey
Injection
The pilot test at the Kortan site consisted of two phases—abiotic and biotic. In
summer 2012, during the first (abiotic) phase of the pilot test, 120 kg of nZVI
426
J. Semerád et al.