19.2.7 Analytical Methods
VOCs were analyzed in a commercial laboratory using standard methods. PLFA were
analyzed by the Institute of Microbiology of the Czech Academy of Sciences. Detailed
description of the utilized analytical methods can be found in Lhotský et al. (2017a, b).
19.3 Results and Discussion
19.3.1 Calcium Peroxide
The initial concentrations of the contaminants in the respective monitoring well just
few hours before the start of injections were as follows—B 32.4 μg/L; T 87.8 μg/L;
MCB 1386 μg/L. The development of the monitored parameters during the field
study is shown in Fig. 19.3.
19.3.1.1 Physicochemical Parameters During the Remediation Pilot Test
As described above, calcium peroxide was injected into two injection points in total
amount of 200 kg in 1000 L of water from the bioreactor. After the injections it was
found out that calcium peroxide penetrated in to the respective monitoring well
causing a significant increase in the pH up to pH 11 one day after the injection. Ten
days after the injection the pH dropped to the neutral range and it remained more or
less stagnant throughout the rest of the test. The E h rose for one day after the injection
up to +225 mV and from that moment on it was gradually decreasing to +75 mV
147 days after the injection. Oxygen concentrations also rose significantly but the
maxima were reached 10 days after the injection reaching up to 7.73 mg/L. Later on, it
decreased again and reached values similar to those prior to the test 56 days after the
injection. CaO 2 injection also caused a gradual increase in the groundwater temperature (21 days after the injection, data not shown) up to +1.1
C compared with the
situation before the injection. Later on, the temperature decreased gradually. One day
after the injection a significant increase in conductivity (data not shown) was also
observed; however, it decreased again to values similar to those prior to the injections.
19.3.1.2 Contaminant Concentrations Throughout the Test
The concentrations of the contaminants are shown in C/C 0 scale so that it can be
easily compared with the data obtained with other oxygen sources. The concentrations of T and MCB significantly rose for 21 days after the injection because of the
pressure pulse caused by the injection while the concentration of B decreased. This
was probably caused by the fact that both T and MCB were partly bound to the soil
416
O. Lhotský
VOCs were analyzed in a commercial laboratory using standard methods. PLFA were
analyzed by the Institute of Microbiology of the Czech Academy of Sciences. Detailed
description of the utilized analytical methods can be found in Lhotský et al. (2017a, b).
19.3 Results and Discussion
19.3.1 Calcium Peroxide
The initial concentrations of the contaminants in the respective monitoring well just
few hours before the start of injections were as follows—B 32.4 μg/L; T 87.8 μg/L;
MCB 1386 μg/L. The development of the monitored parameters during the field
study is shown in Fig. 19.3.
19.3.1.1 Physicochemical Parameters During the Remediation Pilot Test
As described above, calcium peroxide was injected into two injection points in total
amount of 200 kg in 1000 L of water from the bioreactor. After the injections it was
found out that calcium peroxide penetrated in to the respective monitoring well
causing a significant increase in the pH up to pH 11 one day after the injection. Ten
days after the injection the pH dropped to the neutral range and it remained more or
less stagnant throughout the rest of the test. The E h rose for one day after the injection
up to +225 mV and from that moment on it was gradually decreasing to +75 mV
147 days after the injection. Oxygen concentrations also rose significantly but the
maxima were reached 10 days after the injection reaching up to 7.73 mg/L. Later on, it
decreased again and reached values similar to those prior to the test 56 days after the
injection. CaO 2 injection also caused a gradual increase in the groundwater temperature (21 days after the injection, data not shown) up to +1.1
C compared with the
situation before the injection. Later on, the temperature decreased gradually. One day
after the injection a significant increase in conductivity (data not shown) was also
observed; however, it decreased again to values similar to those prior to the injections.
19.3.1.2 Contaminant Concentrations Throughout the Test
The concentrations of the contaminants are shown in C/C 0 scale so that it can be
easily compared with the data obtained with other oxygen sources. The concentrations of T and MCB significantly rose for 21 days after the injection because of the
pressure pulse caused by the injection while the concentration of B decreased. This
was probably caused by the fact that both T and MCB were partly bound to the soil
416
O. Lhotský