Monitoring and Reporting
Performance monitoring
During the injector
installation, soil and groundwater samples are obtained and
analyzed to establish baseline contaminant concentrations.
Following the completion of the primary or pilot injection,
GCI requests groundwater samples be obtained from the same
locations sampled as post-treatment.
The requirement of post treatment soil sampling is dependent
on the goals of the treatment program. Once the analytical
results are received, GCI will perform the polish injection
into areas on site where additional percent reductions are
needed.
Daily GW Monitoring
Each day groundwater samples are obtained from area injectors and monitoring wells within the active treatment region
and sampled for pH, alkalinity, iron, chloride, peroxide
concentration, PID headspace, and temperature. These parameters
enable GCI to modify the injectate to establish optimal conditions
and proportion the reagent to areas where additional treatment
is needed.
| Hydraulic
Conditions During Injection |
|
Typical observations during a Fenton’s reagent injection
include a reduction in pH and alkalinity, indicating scavenging
carbonates have been eliminated. An initial increase of PID
headspace occurs due to desorption and dissolution of contaminants
sorbed to soil into groundwater. PID headspace will then
begin to decrease proportionately to the increase in peroxide
concentrations. If the site contains chlorinated hydrocarbon contamination,
chloride concentrations will increase as PID headspace decreases
indicating destruction.
Daily Offgas Monitoring
Periodically throughout the injection, GCI monitors the offgas
from the injectors and monitoring wells within the active treatment
region. The offgas is analyzed for PID headspace and oxygen
and carbon dioxide percentages. Offgas PID measurements are
taken to ensure that breathing zone conditions are not compromised.
Oxygen is created by the decomposition of hydrogen peroxide
and carbon dioxide is formed by the destruction of organics.
During a typical application, one would expect to see the CO2 production to follow a bell shaped curve. At the beginning
of the injection, the CO2 levels will begin to rise as the
carbon of the contaminant is destroyed. As the injection progresses,
the carbon dioxide levels begin to stabilize. Since carbon
dioxide is an end product of the reaction between the hydroxyl
free radical and the contaminant, this indicates that there
is no longer significant contaminant present within this region. Once the
contaminant has been destroyed, the oxygen concentration will
increase as the carbon from the contaminant is consumed and
the peroxide finally decomposes to water and oxygen.
| Field
Observations During
Injection |
|
Reporting
Throughout the duration of the injection, GCI provides weekly
updates to our clients containing injection quantities and
field observations. Following the completion of the injection,
GCI provides a progress report complete with the data
collected during the injection. Once post-treatment analytical
results are received, GCI issues an effectiveness evaluation
report, which details the installation of the injectors, complete
with boring and construction logs, an anaylsis of the baseline
contaminant mass, a summary of the field activities and observations,
and an analysis of the effectiveness of chemical oxidation
on the contaminant mass. |
