the results of the tests, it can be assumed that the increase in concentrations was
caused mainly by the influx of the contaminated water from the surrounding
untreated areas rather than by a rebound effect.
19.3.1.3 Microbial Biomass
The concentration of the respective PLFA is shown as C/C 0 so that it can be easily
compared with the data obtained with other oxygen sources. It can be seen that the
water samples provide different results compared with those from the in situ
microcosms. In the case of the water samples, variation of the results was significant
while in the case of soil, it was clear that the initial high pH caused by the presence of
CaO 2 in the monitoring well had negative impact on the bacteria present in the well
even 21 days after the injection. In the following days the bacterial biomass in the
microcosms grew substantially to reach the maximum 56 days after the injection;
later on, it gradually decreased although even 147 days after the injection it was still
elevated in comparison with the initial values.
19.3.2 Modified Calcium Peroxide
The initial concentrations of contaminants in the respective monitoring well just few
hours before the start of the injections were as follows—B 57.2 μg/L; T 3245 μg/L;
MCB 2840 μg/L. The development of the monitored parameters during the field
study is shown in Fig. 19.4.
19.3.2.1 Physicochemical Parameters During the Remediation Pilot Test
Modified CaO 2 application results are shown in Fig. 19.4. This material did not
penetrate into the monitoring well and its impact on the pH values was rather low
and gradual as the pH reached 7.14, 87 days after the injection. The effects on the E h
were also less pronounced and more gradual compared with common CaO 2 , the
maximum of +134 mV was achieved 21 days after the injection and it remained
elevated even 87 days after the injection. In the case of the O 2 concentration, the
effects were similar and a gradual increase to values around 0.4 mg/L was observed.
Afterwards, the O 2 concentration remained stagnant until 87 days after the injection.
147 days after the injection the O 2 concentration dropped to values comparable with
the ones measured prior to the injection. In the case of groundwater temperature, a
slight gradual increase (data not shown) up to +2.4
C was observed 10 days after the
injection. Later on, the temperature decreased gradually. No significant effect of the
injection on conductivity (data not shown) was observed.
418
O. Lhotský
caused mainly by the influx of the contaminated water from the surrounding
untreated areas rather than by a rebound effect.
19.3.1.3 Microbial Biomass
The concentration of the respective PLFA is shown as C/C 0 so that it can be easily
compared with the data obtained with other oxygen sources. It can be seen that the
water samples provide different results compared with those from the in situ
microcosms. In the case of the water samples, variation of the results was significant
while in the case of soil, it was clear that the initial high pH caused by the presence of
CaO 2 in the monitoring well had negative impact on the bacteria present in the well
even 21 days after the injection. In the following days the bacterial biomass in the
microcosms grew substantially to reach the maximum 56 days after the injection;
later on, it gradually decreased although even 147 days after the injection it was still
elevated in comparison with the initial values.
19.3.2 Modified Calcium Peroxide
The initial concentrations of contaminants in the respective monitoring well just few
hours before the start of the injections were as follows—B 57.2 μg/L; T 3245 μg/L;
MCB 2840 μg/L. The development of the monitored parameters during the field
study is shown in Fig. 19.4.
19.3.2.1 Physicochemical Parameters During the Remediation Pilot Test
Modified CaO 2 application results are shown in Fig. 19.4. This material did not
penetrate into the monitoring well and its impact on the pH values was rather low
and gradual as the pH reached 7.14, 87 days after the injection. The effects on the E h
were also less pronounced and more gradual compared with common CaO 2 , the
maximum of +134 mV was achieved 21 days after the injection and it remained
elevated even 87 days after the injection. In the case of the O 2 concentration, the
effects were similar and a gradual increase to values around 0.4 mg/L was observed.
Afterwards, the O 2 concentration remained stagnant until 87 days after the injection.
147 days after the injection the O 2 concentration dropped to values comparable with
the ones measured prior to the injection. In the case of groundwater temperature, a
slight gradual increase (data not shown) up to +2.4
C was observed 10 days after the
injection. Later on, the temperature decreased gradually. No significant effect of the
injection on conductivity (data not shown) was observed.
418
O. Lhotský