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Bruce R. Thompson, de maximis, inc. andMichael J. Gefell, P.G., C.P.G., Anchor QEA, LLC
Estimating the Costs of and Performing the Remedy at the Solvents Recovery Service of New England
(SRSNE) Superfund Site
1965
1980
N100 feet
30.5 meters
Inset photos look N
• SRSNE re-distilled millions of gallons of solvents 1955 to 1991. NAPLs (chlorinated alkenes and alkanes, aromatics/TPH, ketones, alcohols, tetrahydrofuran, 1,4-dioxane and PCBs) in overburden and bedrock.
• >2,000 former customers formed Group in 1992. Group completed two de minimis settlements, two groundwater NTCRAs, RI/TI Evaluation, FS and RD/RA. 2005 ROD selected:
In-situ Thermal Remediation (ISTR) for overburden NAPL, followed by RCRA C cap over that area,
hot spot soil/sediment excavation and Institutional Controls, and
hydraulic containment and MNA for groundwater and bedrock NAPL.
• ROD - $29.23 MM. ROD remedy duration>225 years (not TI).
Background
Gordon Cooper: You boys know what makes this bird go up?
FUNDINGmakes this bird go up.
Gus Grissom: He's right.
No bucks, no Buck Rogers.
Updating ROD Costs for RD/RA Settlement
•Groundwater and sediment NRD, EPA past and future oversight, admin (legal, investment advisor, and trustee), and interim P&T O&M.
• Costs for ROD elements not in FS ‐ IQAT, dioxin delineation & remediation, RCRA C cap (instead of B), VI study, NAPL and GW delineation, future risk assessments.
•Updated FS costs ‐ increased O&M duration to 100 years, changed discount rate for PW O&M estimate from 7% to 3%.
• 2008 estimate / settlement basis: $61.2 million
Effect of Discount Rate on Present Worth O&M Cost
100‐Year O&M Cost
Discount RateNo Discount
0.0%2018*0.6%
2016*1.5%
2007*3%
FS 2005**7%
$39,893,000 $32,907,000 $25,545,000 $18,062,000 $9,634,000
**EPA uses 7% discount rate for FS analysis, based on the NCP (55 FR 8722) and “Revisions to OMB Circular A‐94 on Guidelines and Discount Rates for Benefit‐Cost Analysis” (OSWER Directive 9355.3‐20, EPA 1993)
*OMB Circular A‐94 ‐ Discount Rates for Cost‐Effectiveness, Lease Purchase, and Related Analyses
0
2
4
6
8
10
1979 1984 1989 1994 1999 2004 2009 2014
OMB Discount Rate (%)
Significant Changes While Implementing the Remedy
• Bedrock NAPL and Groundwater Delineation• Dioxin Delineation and Remediation• In‐situ Thermal Remediation (ISTR)• Discount Rate for Present Worth O&M
• EPA Oversight• Groundwater Monitoring
Cost increases
Cost Decreases
>10% OF EFFECTIVE SOLUBILITY
ALCOHOLS DETECTED
NAPL OBSERVED
AVERAGE BEDROCK FRACTURE ORIENTATION
22 EN17E
LEGEND
14 GALLONS DNAPL
170‐177 ft bgsMW‐907DR
ITRC FracRx‐1 Case Study 11.2
Bedrock DNAPL Zone Delineation
• ROD required remediation to 1 ppb TEQ, background, or other level TBD during RD. ~96 samples collected for TEQ & homologue analysis.
• Calculated 34 ppt TEQ recreation‐based clean up level. • Remediated to 30 ppt TEQ local background.
Dioxin – Delineate, Establish Clean Up Level, and Remediate
“Incinerator”
ISTR – May 2014 – March 2015
Implementing ISTR• 496,400 pounds VOCs removed, soil cleanup levels met –99.7% soil TVOC reduction, >95% groundwater TVOC reduction
Total Cost = $17.3 MM (FS/ROD estimate $17.7 MM) But FS/ROD estimate included 40% contingency, used on:
– Infrastructure (bought 1/2 ac., moved fiber‐optic line, installed gas & sewer lines, extended sheet‐pile wall, temporary power line (23 kV, 145 A, 6 MW)
– Phased treatment & vapor treatment approach– 20% volume increase (lateral and vertical expansion) and resultant changes during installation
100
1,000
10,000
100,000
1,000,000
3/7/13 3/7/14 3/7/15 3/7/16 3/7/17
Concen
tration (µ
g/L)
Total VOCs 8260B Chloride‐ 325.3BTEX DCE+VC+CE
NTCRA 1 Influent VOCs and Chloride
ISTR Ends
Unit Remedial Costs
• Basis for estimates include:
– 25 year track record of groundwater monitoring data,
– 23 year track record of Pump & Treat (P&T) operation, and
– 2015 Site Conceptual Model Update prepared for 2nd Five-Year Review
• For the SRSNE Site, the total VOCs removed and unit costs are:Degradation 300,000 kg (25 years) $ 7 / kgISTR 225,000 kg (1 year) $ 77 / kgP&T 6,700 kg (23 years) $2,600 / kg
Completed Remedy – September 2017
Groundwater Monitoring Network
& Most Recent TVOC Results
Current TVOCs (µg/L)
NAPL collected
1
10
100
1,000
10,000
100,000
Dec‐96 Dec‐06 Dec‐16
ug/L
P-101B
100,000
1,000,000
10,000,000
Jun‐97 Jun‐07 Jun‐17
ug/L
MW-705DR
0.1
1
10
100
Dec‐96 Dec‐06 Dec‐16
ug/L
MW-707DR
Optimization• Groundwater Monitoring
– No‐purge sampling in plume core (low‐flow at plume margins)– Further reduced frequency & analytes (25‐years of trend data)
• Groundwater Treatment (planned Summer 2018)– Shut down inner extraction (NTCRA 1) with full‐scale PlumeStop®/ZVI pilot to address PFOA/PFOS and reduce VOCs
– Change from on‐site treatment to POTW discharge for long‐term hydraulic containment (NTCRA 2)
• Continue evaluating 1,4‐dioxane MNA (anticipating 2019 ESD to set cleanup level)
• Retained financial advisor for long‐term investments
Conclusions• ROD requirements that are open‐ended / uncertain scope require larger contingencies.
• Discount rate for present worth O&M cost estimate needs to correlate to investment rate of return.
• Consider potential for emerging contaminants, declining detection limits, and reductions in risk‐based clean up levels when establishing contingencies.
• Optimize, optimize, optimize.
Questions?Bruce Thompsonde maximis, inc.860 298 0541
http://www.srsnesite.com/
www.epa.gov/superfund/srs
