Remediation and High Resolution Site Characterization Services

Value Added Strategies to
Maximize Remediation
Scott Wisher, PG, Michael Mazzarese, Eliot Cooper, Mike Jahn
Vironex Technical Services, LLC
In a Perfect World, Remediation
Would Look Like This
Release
Closure
Investigation
Remediation
It can be a vicious cycle of
dollars, time, and effort.
Our industry continues to
evaluate methods to go
from release to closure
without this cycle.
Today’s Challenges For Remediation
• The remaining sites are complex
• Heterogeneities complicate remediation
• Understanding COC and NAPL mass distribution
versus geology and hydrogeology (e.g. K, seepage
velocity) is key to remedial success
• Funding
Traditional investigation methods alone, while
valuable, do not meet the needs of today’s
challenging sites.
Integration of High Resolution Site
Characterization (HRSC)
• Conceptual Site
Model (CSM)
Refinement
• Pre-Design
Investigation
– Monitoring wells
provide averaged
contaminant and
hydraulic data
– More accurate
lab data (e.g.
SOD) and design
from discrete
soil/GW samples
Well Screen Zones
Site #1: Field Application (ASP)
and Approach
Release
Closure
Investigation
Remediation
Site #1: Remediation Planning
• Following design based on MW
data, suggest applying HRSC data
• 2 Day HRSC (MIP) and 2 Day pilot
testing performed in same
mobilization.
– Collected SOD (0.5 g/kg) and soil
buffering samples.
– Injection tooling selected and
distribution verified (using EC)
• Two modified full scale injections of
caustic ASP completed following
HRSC data review
– 10-15% ASP, 75% mobile pore
volume
HRSC Data
MW-18
MW-5
MW-8
PID > 1e+07
Former USTs
Approximate
Well Screen
(10-20 ft)
Electrical Conductivity (mS/m)
Reagent Distribution Assessment
500
450
400
350
300
250
200
150
100
50
0
Injection Zone
0
1
2
3
4
5
6
7
8
9
10 11 12 13 14 15 16 17 18 19 20
Depth below grade (ft)
Baseline
2 ft, IP-8S
4 ft, IP-8S
Post HRSC Injection Plan
Results
Results (cont.)
BTEX + MTBE vs. Time
MW-5
70,000
BTEX + MTBE, ppb
60,000
50,000
40,000
30,000
20,000
10,000
0
MW-8
MW-18
Inj Event #1
Inj Event #2
Rebound Assessment
Benzene Soil Mass Major Design Component
6-months
post injection,
Rd 1
BTEX + MTBE
concentrations
rebounded 67-88%
lower at 6 months,
Rd 2 versus Rd 1
6-months post
injection, Rd 2
Project Summary
Site #2 - Pilot Test Optimization
• Active manufacturing site with PCE contamination
– SVE system operated for several years
• 2 – 30 ft x 30 ft pilot test areas selected based on
traditional data
– Course glacial till shallow, increasing fines with depth
• MIP survey performed in each area before KMnO4 pilot
testing (1 day per area)
– Reagent distribution assessment performed using EC
– NOD samples collected from impacted zones (shallow and deep)
– 6 month sampling plan to assess back diffusion
• Due to low seepage velocity, injection volume based on
100% mobile pore volume of 3% KMnO4
Pilot Test Area #1
Pilot Test Area #2
Design injection zone
Vadose mass
remaining
Modified
injection zone
Design injection zone
?????
Summary
In summary, use of high resolution site characterization
techniques, when utilized correctly, can be effective to
better understand subsurface conditions with respect to
contaminant mass, contaminant distribution, and
injection parameters.
Mike Jahn, PG
Rocky Mountain Region Operations Manager