Post on 29-Aug-2020
TRB Summer Workshop – Presented by Jeff Gernand and Shawn Schmelzer July 20, 2017
Thermal Remediation of TCE at a Former Asphalt Lab
Presentation Purpose
Describe site conditions.
Describe thermal treatment technology and why it was used.
Present results and lessons learned.
Site Location
Maryland DOT SHA’s former Eastern Regional Lab, 7857 Ocean Gateway, Easton, MD
US 50
SITE
Site History
1963 – 1988 – SHA operates the lab; TCE was used to extract aggregate from asphalt core samples
Mid 1980’s – SHA and MDE begin site assessment
1994-2003 – SHA operates groundwater pump and treat
2008 – SHA and MDE sign a Consent Order
2008-2011 – SHA completes the RI/FS process and develops the Thermal Remediation Work Plan
Project History
2011, SHA awarded a performance based contract : Contractor to design, install, and operate Reduce TCE in soil by an average of 95% Meet MDE Non-Residential Cleanup Standard for TCE in Soil
Remediation to be completed within 210 calendar days
SHA awards to the lowest bidder; must meet Contractor Equipment and Experience Statement
Contract successfully completed in September 2012, post-remediation groundwater monitoring underway
RI - Geologic Cross-Section
MIP
MIP – Conceptual Site Model
RI – MIP Results in Section
RI – MIP Results in Plan
Remedial Investigation Findings
TCE Contamination • Soil – Ranges up to 360,000 ppb • Groundwater – Ranges up to 230,000 ppb • Evidence of DNAPL • Source in Clay to 43 ft bgs; 2,324 Ft2
Remediation Requirements: • Cleanup Standard for Soil = 7,200 ppb • MDE required TCE mass removal
RI – TCE Source Area
Thermal Treatment – Application at ERL
Install 16 electrodes (41-51 feet deep) Apply electrical current to heat the soil to an
average of 87 degrees C Apply vacuum to collect the generated steam
and vapor for treatment Sample vapor to determine that flux peaked Use soil samples to document 95% TCE
reduction in the source area
Thermal Treatment Concept
Electrode Construction
Electrode Field
Thermal Treatment – Treatment Train
Thermal Treatment – Offgas Monitoring
Thermal Treatment – Field Monitoring Criteria
Thermal Treatment – Confirmatory Soil Sampling
Thermal Treatment – Results Energy applied: 923,070 kWh Subsurface temperatures: 87⁰ – 100+⁰ C VOC removal up to 3.3 lbs./ hour 38 soil samples; Days 66, 125, and 140 Operated for 141 days (vs. 50-70 estimated) 1,500 lbs. of TCE recovered
Post-Remediation Monitoring Network
Monitoring Results - Source
0
50,000
100,000
150,000
200,000
250,000
7/1/2007 7/1/2008 7/1/2009 7/1/2010 7/1/2011 7/1/2012 7/1/2013 7/1/2014 7/1/2015 7/1/2016
ppb
Treatment Zone Results (composite maxima) Trichloroethene (TCE) cis-1,2-Dichloroethene Vinyl Chloride
Thermal Treatment
0
50,000
100,000
150,000
200,000
250,000
7/1/2007 7/1/2008 7/1/2009 7/1/2010 7/1/2011 7/1/2012 7/1/2013 7/1/2014 7/1/2015 7/1/2016
ppb
Treatment Zone Results (composite maxima)
Trichloroethene (TCE) cis-1,2-Dichloroethene Vinyl Chloride
Thermal Treatment
Monitoring Results – MW-10
Thermal Treatment
0
50000
100000
150000
200000
250000
300000
3/19/2009 3/19/2010 3/19/2011 3/19/2012 3/19/2013 3/19/2014 3/19/2015 3/19/2016 3/19/2017
MW-10 Results - at Source Area Scale
Trichloroethene (TCE) cis-1,2-Dichloroethene Vinyl Chloride
Thermal Treatment
Monitoring Results - MW-10
Thermal Treatment Thermal Treatment
Monitoring Results - MW-12s
Thermal Treatment Thermal Treatment
0
20
40
60
80
100
120
3/1/
2009
6/1/
2009
9/1/
2009
12/1
/200
9
3/1/
2010
6/1/
2010
9/1/
2010
12/1
/201
0
3/1/
2011
6/1/
2011
9/1/
2011
12/1
/201
1
3/1/
2012
6/1/
2012
9/1/
2012
12/1
/201
2
3/1/
2013
6/1/
2013
9/1/
2013
12/1
/201
3
3/1/
2014
6/1/
2014
9/1/
2014
12/1
/201
4
3/1/
2015
6/1/
2015
9/1/
2015
12/1
/201
5
3/1/
2016
6/1/
2016
9/1/
2016
12/1
/201
6
3/1/
2017
ppb
MW-13 Results (260 feet downgradient)
Trichloroethene (TCE) cis-1,2-Dichloroethene Vinyl Chloride
Thermal Treatment
Monitoring Results - MW-13
Thermal Treatment – Lessons Learned Work with your regulator, define and document
measureable goals Mixtures of TCE and asphalt influence the remedy Be cautious using old data to specify the remedy Be cautious drawing the source area boundary at
the property line Performance-based contracts address risk and
reduce design effort If performance is based only on parent material
concentrations (e.g. TCE), consider that daughter product concentrations may increase
Comments/Questions?
KCI Contact: Mr. Jeff Gernand
410-891-1810 jeffrey.gernand@kci.com
SHA Contacts:
Mr. Greg Keenan 410-582-5585
gkeenan@sha.state.md.us
Mr. Shawn Schmelzer (410) 582-5589
sschmelzer@sha.state.md.us