PATHWAY TO CLOSURE AT LNAPL SITES

PATHWAY TO CLOSUREAT LNAPL SITESA Case Study

Railroad Environmental ConferenceOctober 2015

Daniel Dyer, CSX Transportation, Inc. Steven Aufdenkampe, Norfolk Southern Corporation Neil Ferrone, Consolidated Rail Corporation Jon Smith, Lauren Alkidas, and Colleen Barton, Arcadis

© Arcadis 2015

Risk-Based LNAPLManagement

© Arcadis 2015

LNAPL may be left in place if lack of risk demonstrated

LNAPL recovery to the maximum extent practicable

LNAPL recovery to a prescriptive well thickness, e.g. less than 0.01 feet

Residual LNAPL is unacceptable

MI, TX, WI, IN, CA, MN, MA, VA, IA, PA, KS, MS

IL, OH, WV, OR IL, NV, NM, MT NJ

The Regulatory Spectrum

© Arcadis 2015

Changes in Regulatory Policy• LNAPL Presence ≠ Risk• Emphasis on LCSM

– LNAPL extent (vertical/horizontal),– Composition concerns, – Saturation concerns

• LNAPL in well ≠ Recoverable– Replaced prescriptive LNAPL

thickness with LNAPL transmissivity criterion

© Arcadis 2015

Site Background

SCALE IN FEET

0 150 300

N

CSX

NS

Conrail

YARD OFFICE

FORMER AST

FORMER ROUNDHOUSE

FORMER OIL HOUSE

FORMER FUELING

PLATFORM

UTILITY CORRIDOR

Historical LNAPL Detections

© Arcadis 2015

LNAPL Delineation - LIF

Residual LNAPLSCALE IN FEET

0 150 300

N

© Arcadis 2015

Petrophysical Data• Fluids

(LNAPL/Groundwater)– Density – Viscosity – Interfacial tensions

• Undisturbed Soil Cores– Locations/depths based on LIF

results– Core photography– Basic soil properties– Field/residual pore fluid

saturations– Capillary properties

© Arcadis 2015

LNAPL Transmissivity• Ideal Metric for Evaluating Recovery Potential

– ITRC (2009): 0.1 – 0.8 ft2/d– Michigan Department of Environmental Quality: 0.5 ft2/d

• ASTM Guidance (E2856) Provides Industry Best Practices

dzkgkTm

nw

z

zrn

n

nn ∫⋅

=

µρ

k = permeabilitykrn = relative permeabilityρn = LNAPL densityg = gravityµn = LNAPL viscosityz = elevation

Well

LNAPL

WaterResidual LNAPL

© Arcadis 2015

LNAPL Transmissivity Results • Field Testing at MW-

35:– May 2014 Baildown

Test: 0.14 ft2/d– January 2015 Skimming

Test: 0.04 ft2/d

• Estimates from LabData– 0.02 to 0.05 ft2/d 0

0.1

0.2

0.3

0.4

0.5

0.6

0

0.03

0.06

0.09

0.12

0.15

0.18

0 400 800 1,200 1,600 2,000

LNAP

L Tr

ansm

issi

vity

(ft2 /

d)

LNAP

L Re

char

ge R

ate

(ft3 /

d)

Elapsed Time (minutes)

January 2015 Manual Skimming Test

LNAPL Recharge RateLNAPL Transmissivity

All Results Below 0.5 ft2/d Threshold

© Arcadis 2015

LNAPL Assessment SummaryN

MW-35 Tn Results (ft2/d)

May 2014 0.14

January 2015 0.04

vn (cm/s) 3.8 x 10-6

LIF-032

Depth (ft) 5.4

Tn (ft2/d) 0.027

vn (cm/s) 3.1 x 10-7

LIF-034

Depth (ft) 9.1

Tn (ft2/d) 0.036

vn (cm/s) 6.6 x 10-7

LIF-024

Depth (ft) 3.5

Tn (ft2/d) 0.008

vn (cm/s) 2.1 x 10-6LIF-011

Depth (ft) 8.4

Tn (ft2/d) 0.005

vn (cm/s) 5.4 x 10-8

LIF-008

Depth (ft) 5.1

Tn (ft2/d) 0.002

vn (cm/s) 2.0 x 10-7

LIF-005

Depth (ft) 2.6

Tn (ft2/d) 0.050

vn (cm/s) 6.6 x 10-6

© Arcadis 2015

Utility Corridor Evaluation

UTILITY CORRIDOR

SEWER MANHOLE/CATCH BASIN

MONITORING WELL

FENCE

HISTORICAL MONITORING WELL

GROUNDWATER ELEVATION

HISTORICAL RECOVERY WELL

APPARENT GROUNDWATER FLOW DIRECTION

GROUNDWATER ELEVATION CONTOURINFERRED GROUNDWATER ELVATION CONTOUR

LEGEND

© Arcadis 2015

Vapor Intrusion Assessment• Direct Evaluation

– Soil Gas Probes– Temporary/Existing Wells

• Groundwater Sampling– May 2014

• Soil Gas Sampling – May 2014, – January 2015, & – September 2015

• No VI Exceedances

© Arcadis 2015

Investigation Conclusions

Next Step: Submit Certificate of Completion Request

Key Takeaways:• Regulatory Policy Changes Catching up with LNAPL Science• Investment in LCSM Reduces Need for Remediation• Regular/Open Communication with Regulatory Agency

• LNAPL Delineation Complete• All LNAPL Impacts On Site

• LNAPL is Not Migrating• LNAPL Recovery is Not Practical• No Offsite Groundwater Issues• No VI Concerns

© Arcadis 2015

Questions/Discussion

1425 September 2015