Description
BENCH STUDY SET-UP
Flow-through column systems (Figure 1) were set up
alongside a control. Each system consisted of an 800-mL column filled with
a soil/EHC mixture, followed by a 2-L jar containing soil only. The
soil-only jar simulates further contaminant reduction downstream of an EHC
zone, since EHC will release dissolved organic carbon and low redox
conditions downstream. Two systems were set up; one with EHC and one with
EHC-A. An application rate of 2% of EHC to soil mass was used.
For each column system, groundwater impacted with CT was pumped from a
TedlarR bag through the column in an up-flow manner at approximately 150
mL/day. This results in a contact time of 2.7 days within the columns and
5.0 days within the downgradient jar (assumes 50% porosity).
RESULTS
After some acclimatization time, both the EHC and EHC-A systems
performed very well with CT and all daughter products below the detection
limit in the effluent water. The effluent water was sampled both after the
column and the following soil jar. Figure 2 shows the
concentration of CT in the influent and effluent water for the two
systems. In addition the soil control system is presented. As shown, the
CT started to break through in the effluent water for the EHC-A system
following 355 days of continuous operation at room temperature. This would
indicate that the EHC-A was consumed and had to be rejuvenated.
Figures 3 and 4 shows the effect on CT and daughter
products over time for the EHC-A system after the column and soil jar
respectively. As shown, the EHC-A removed the CT without generation of
daughter products. Breakthrough occurred for CF after approximately 230
days in the column and after approximately 270 days following the soil
jar.
Companies On This Project
ADVENTUS GROUP
