Former Defense Supply Center 

Philadelphia (DSCP) Site

1

Public Involvement

Teleconference Date: December 15, 2021 Time: 6:30-8:30 PM
Purpose of this Teleconference

• Engage the public

• Assist the public with review of the Remedial Investigation Report 

and Cleanup Plan (RIR/CP)

• 90-day public comment period 

• Present a summary of clean-up activities completed to date 

• Provide a forum for the public to ask questions

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How to Ask Questions

Q&A session will be held at the end of our presentations.

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• This teleconference is being hosted on Microsoft Teams. 

• To ask a question, open the meeting chat window by clicking the 

“Show conversation” button

• Enter question in the chat window that pops up where it says “type 

new message”, then click the arrow on the right to submit your 

question

• We will conduct our presentations first, but feel free to submit 

questions as we go. We will answer them at the end of the 

presentations.
Audio Only Guide 

Q&A session will be held at the end of our presentations.

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• If you are unable to provide an email or join via 

MS Teams, you can call in for audio only:

Audio only

+1 267-807-0624,,823996214#

United States, Philadelphia 

Phone Conference ID: 823 996 214#

• Audio Only will not allow you to see our 

presentation.

• To ask a question, Press *5 on your phone. 

This will raise your hand. The moderator will 

indicate when your microphone has been 

enabled.

• When you microphone is enabled, to speak 

your question, Press *6 
Project Team Introduction 

5

Project team members in Attendance:

Defense Logistics Agency (DLA)

• Bradley Clawson

• Stephen Porch

United States Army Corps of Engineers (USACE)

• Sterling Johnson

• Steve Langseder

• Vincent Grassi

Seres Arcadis Joint Venture (JV)

• Matt Lesley

• Meredith Braverman

• Carlo Di Tullio

• Jessica Travis

Montrose (PARS) Environmental Group

• Eric White
Agenda

Q&A session will be held at the end of our presentations. 6

• Presentation (approximately 1 hour)

• Introduction 

• Location, Objectives, History of Public Involvement, Act 2 

Process 

• Background, regulatory history, selection of standards, site 

characterization 

• Conceptual Site Model: Hydrogeology & Environmental 

Impacts

• Cleanup Plan, Site Remedial Actions, Engineering Controls

• Summary of Presentation

• Q&A Session (Approximately 45 minutes)
Location and Background

• Historic military supply depot on the 

National Register of Historic Places

• Philadelphia Quartermaster Depot was 

constructed during World War I to expand 

the Schuylkill Arsenal

• Expanded to current footprint during World 

War II

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Location and Background

• Textile manufacturing for the military, such as 

uniforms, shoes, coats, blankets, sleeping bags, etc.

• Expanded during World War II

– Employed 15,000 people between1941 

through 1945 at its peak

– Maintained a work force of around 5,000 

people after the end of WWII until closure in 

1993

• Closed under Base Realignment and Closure 

(BRAC) in 1993 at which point environmental 

Investigation commenced

8
Objectives for Public Involvement

• Public Involvement Plan – March 2021

• Re-engage with our community stakeholders, which includes:

• Residents and neighbors 

• Interested or involved agencies, property owners

• Local businesses and environmental organizations

• Your representatives in the City of Philadelphia 

• Enable a two-way communication between stakeholders and the Defense 

Logistics Agency (DLA)

• Provide an update to stakeholders about past, ongoing and planned site 

environmental clean-up efforts

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Where to find the report

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The full Remedial Investigation Report and Cleanup Plan is available for 

review at the following website:

https://www.dla.mil/HQ/InstallationManagement/DoingBusinessWithInstallation

Management/EnvironmentalDocuments/
History of Public Involvement

Quarterly Progress Reports available at the PADEP Office

• Restoration and Advisory Board (RAB) –

1996 – 2011

• 2004 Public Involvement Plan (PIP) 

created

• Regular meetings stopped when clean-up 

was implemented

• Community Involvement Evolution: Post 

RAB, interested stakeholders and property 

owners impacted by clean-up efforts 

received quarterly progress reports

• 2021 Updated PIP 

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Act 2 Process

Remedial Investigation 

Report / Cleanup Plan Final Report Notice of Intent to 

Remediate 

Selects Act 2 Standard

Site-specific standard pathway 

elimination approach selected

Public Notice & 

Comments Period

Site Characterization

Includes Human Health Risk 

Assessment

Includes Cleanup Plan

Summary of clean-up activities

Description of engineering & 

institutional controls

Public Notice & 

Comments Period

Summarize All Act 2 

Activities and Post 

Remedial Care

Institutional Controls 

Public Notice & 

Comments Period

Demonstration of 

Attainment

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Former DSCP RIR/CP Components

RIR is the comprehensive report and problem statement for clean-up 13

• Remedial Investigation Report

• Executive Summary

• List of Contacts

• Site Maps

• Site Description/Environmental Setting

• Selection of Standards

• Site Characterization and Conceptual Site Model

• Contaminant Fate and Transport

• Site-Specific Human Health Risk Assessment
Regulatory History

• 1996 Administrative Order (AO) 

• Remedial actions commenced for petroleum hydrocarbon Light NonAqueous Phase Liquid (LNAPL)

• Interim Remedial Actions (IRA)

• 1999 AO

• Remove LNAPL to maximum extent practicable

• Act 2 - Remedial standards and path-to-closure

• Notice of Intent to Remediate – April 14, 2017

• Site specific standard / pathway elimination 

• Strategy to stabilize residual LNAPL

• Remedial Investigation Report/Cleanup Plan (RIR/CP) Planned submittal 

date May 2022, after 90-day public comment period ends

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What are we remediating at DSCP?

This project is about clean-up of Site LNAPL and eliminating 

risk.

• Historic petroleum hydrocarbon contamination 

• LNAPL = Light Non-Aqueous Phase Liquid

– Less dense than water

– Doesn’t mix with water; remains a separate 

phase liquid, but adheres to soil

• LNAPL is a middle petroleum distillate 

– Density between gasoline and diesel 

• 1,076,810 gallons recovered to date

15

Image courtesy of Interstate 

Technology and Regulatory 

Counsel

Image of LNAPL sample

from DSCP
Constituent compounds from LNAPL in 

Site media:

• Dissolve into groundwater

– Risk of exposure to impacted ground 

water

• Adhere to soil

– Risk of absorption through the skin by 

direct contact for utility workers

• Volatilize into vapor

– Potential for vapor intrusion into buildings 

posing an inhalation risk

16

Potential exposure risks from the 

LNAPL at DSCP

Limits of 

Smear 

Zone

Currently no known or anticipated impacts in project site.
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Media Description

Currently no known or anticipated impacts in project site.

Hawaii State Department of Health
Site Characterization/Conceptual Site Model (CSM)

CSM purpose is to define the impacted media, identify exposure routes, 

guide risk assessment, and inform mitigation approach(es)

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• What is a Conceptual Site Model (CSM)?

• PADEP defines a CSM as “a written and [/or] graphical 

representation of the site environmental system and the 

processes that control the transport and movement of 

regulated substances through the environmental media and 

how they interact.”

• Developed using:

– Site historical information (maps, documents, infrastructure plans, 

etc.) 

– Site investigation-derived data (drilling and well construction logs, 

survey data, groundwater measurements, sampling data, O&M data, 

etc.

• “Living Model”- constantly updated with new information
Regional Geology and Hydrogeology

North

A

A’ 19
from USGS, 1991

Regional Geology and Hydrogeology

• Sediment Wedge is like a giant cake

• Cake separated by frosting (sands separated by clays)

• Groundwater occurs in multiple separate layers

• Frosting (clay) is not present everywhere 20

A A’

Site
Site Geology and Hydrogeology

21

North
Extent of Affected Media

22

North
Distribution of Petroleum HydrocarbonRelated Impacts

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• LNAPL 

• Initial source of resultant impacted media (soil, groundwater vapor), and resulting Act 2 Site are 

controlled by hydrogeology

• Groundwater

• Primarily in shallow aquifer

• Deep aquifer impacts due to local absence of separating clay layers, extends beyond LNAPL 

footprint to the southwest

• Soil

• Coincident with historical LNAPL footprint 

• Thickness due to fluctuations in GW with time (smear zone)

• Vapor

• Limited to areas above historical extent LNAPL

• Primarily coincident with disturbance/historical and recent construction (utility trenches, 

excavations > 10 feet)

• Clean-up and risk mitigation goals focused on stabilizing residual LNAPL and managing impacted 

media
Former DSCP Site Goals

• Goal #1 – Remediate to maximum extent practical by stabilizing 

residual LNAPL 

• Goal #2 – Eliminate potential groundwater exposure pathways 

using institutional controls

• Goal #3 - Eliminate potential soil exposure pathway using 

institutional controls

• Goal #4 - Eliminate potential soil vapor exposure pathways

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Engineering and Institutional Controls

• An Engineering Control is a physical modification to a 

structure or property that prevents risk of exposure to 

contamination

• Example: vapor mitigation system

• Institutional controls are administrative and legal 

controls that help minimize the potential risk of exposure 

to contamination 

• Example: deed restriction

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Engineering and Institution Controls remove risk and keep people 

safe
Goal #1 – Remediate LNAPL to Maximum 

Extent Practical

• Stabilize LNAPL through recovery and in situ 

degradation 

• LNAPL stability criteria proposed:

1. Change in composition of LNAPL (reduce 

volatility / solubility)

2. Decrease LNAPL transmissivity to below 

Interstate Technology and Regulatory Council 

(ITRC) guidance of 0.8 ft/day

3. Decreasing trend of dissolved constituents of 

concern (COC, such as benzene) in site 

groundwater 

ITRC Source https://lnapl-3.itrcweb.org/

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Image courtesy of the American Petroleum Institute
Goal #2 - Eliminate Potential Groundwater 

Exposure Pathway

• No current public usage of groundwater for consumption

• Public water is provided from the Philadelphia Water Department 

• Prohibit future groundwater usage by institutional control

• Prevent groundwater exposure

• Institutional controls prevent future use of groundwater 

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Eliminates risk of using groundwater with 

residual LNAPL contamination

City water for 

potable use Well

Groundwater 

elevation
Goal #3 - Eliminate Potential Soil Exposure 

Pathway

• Soil contamination is below 11ft

• Institutional controls to protect workers

• Controls such as a soil management plan keep utility workers safe from exposure 

for excavations below 11ft

• Restricting use of soil below 11ft to prevent potential direct contact exposure to 

residual soil contamination 

Sewer trench construction 28

Image courtesy of Tetra Tech
Goal #4 - Eliminate Potential Soil Vapor 

Exposure Pathway

• Vapor intrusion assessment to determine 

engineering and institutional control needs 

in commercial and residential structures

• Document existing engineering controls 

present in many Site buildings such as in 

Quartermaster Plaza and Siena Place

• Assess risk in structures within the 

proximity boundary of the historic extent 

of Site LNAPL

• Engineering controls such as vapor 

mitigation systems will be implemented 

where required

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Industrial building with active vapor mitigation system

Example of a passive vapor barrier 
Act 2 Site 

Boundaries

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North
Act 2 Site 

Boundaries

31

North
Act 2 Site 

Boundaries

32

North
Act 2 Site 

Boundaries

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North
Former DSCP RIR/CP Components

Adjudicated public comments will be included in final report to PADEP.

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• Cleanup Plan

• Clean-up Summary and Remedial Alternatives

• Remedial Design and Construction

• Remedial Operations

• Clean-up and Engineering and Institutional Controls

• Post Remedial Care Plan

• Cooperation of Third Party

• Public Comments
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LNAPL Clean-up Timeline

1996 Active clean-up commenced IRAs

Vacuum truck extraction and skimming

1999 Fixed skimming systems installed

DSCP, Former Passyunk Homes, and modular systems 

2001 Vacuum Enhanced Skimming Pilot Study

Internal combustion engine vapor treatment

2005 Vacuum enhanced skimming commenced

Enhanced LNAPL recovery using low applied vacuum

2011 Optimization of Vacuum Enhanced Skimming

Focused Higher Vacuum Extraction and Bioventing

2019 Biovent-Biosparge pilot system installed

Accelerated in-situ biodegradation of LNAPL

Vacuum truck at DSCP

ICE pilot system at DSCP, image courtesy of Tetra Tech
Expanded Skimming Systems

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• Installed in 1999

• 49 recovery wells

• Skimmer pumps with floating intakes 

• Periodic use of Solar-powered modular 

skimmers

Image courtesy of Federal 

Remediation Roundtable, FTR.org Skimmer pumps and solar 

powered modular skimmer 

at DSCP
Skimming Operations

• Majority of recoverable 

LNAPL was recovered 

from 1999 to 2005

• Decreasing LNAPL 

recovery led to the cleanup alternative evaluation

Skimming yields diminishing results 37
Clean-up Alternatives

• Vacuum enhanced 

skimming

• Biovent / Biosparge

• Expansion of skimming 

network

• Bioslurping or multi-phase 

extraction

• Groundwater pump and 

treat

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VES System 

Compound at 

DSCP
The Vacuum Enhanced Skimming 

(VES) System

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• Network of 54 recovery wells 

• Vacuum from 40Hp blowers draw vapor from wells to a common manifold. 

• Increases LNAPL recovery; volatilizes LNAPL, recovered as vapor 

• Promotes bioremediation by soil venting 

• Vapor treated by thermal oxidizer

LNAPL Smear Zone

LNAPL 

Surface Water Surface

Vapor Flow

Figure modified from EPA
0

20,000

40,000

60,000

80,000

100,000

120,000

0

2,000

4,000

6,000

8,000

10,000

12,000

14,000

16,000

Clean-up: Vacuum Enhanced 

Skimming (VES)

LNAPL Vapor Recovery

104,861 

gallons

System enhancements generate greater results.

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Biovent/Biosparge System

The Biovent/Biosparge injects air above and below the 

water table to add oxygen and promote bioremediation.

US EPA 510-B-17-003 October 2017

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42

Biovent/Biosparge System

• Pilot BV/BS System operating since 2019

• Performance monitoring show bioremediation 

accelerating in the pilot area

BV/BS 

Pilot 

Area
43

Biovent/Biosparge System

• Pilot BV/BS System operating since 2019

• Performance monitoring show bioremediation 

accelerating in the pilot area

BV/BS 

Pilot 

Area

Proposed 

BV/BS 

Expansion 

Areas
Engineering and Institutional Controls

• Vapor mitigation systems

• Passive vapor barriers

• Quartermaster Plaza buildings and Siena Place Homes

• Active Sub-Slab Depressurization Systems (SSDS) 

• Similar to radon mitigation systems

• Planned for large commercial buildings

• Pollack Packer Avenue Sewer Venting System

• Deed restrictions for properties over historic LNAPL plume:

• Restrict use of groundwater and soil below 11ft

• Maintain vapor mitigation systems where needed

44
Clean-up Goals per Media Impacted

Site Specific Standard - Media & Pathway Elimination Approach 

For the LNAPL affected media:

• LNAPL – Demonstrate stability

• Shallow Groundwater – Prohibit use 

• Deep Groundwater – Prohibit use

• Soil – Soil Management Plan

• Soil Vapor

• Risk Assessment – Pathway elimination

• Engineering Controls

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Major points of the Former DSCP presentation

Remedial Investigation Report

• Project contacts and project information

• History

• Conceptual site model 

Cleanup Plan

• Goals and clean up progress

• Activities to enable clean up and site closure

46

Summary Slide

No known or suspected public health impacts
Question and Answer Session

• Questions or comments for the project team? 

• Can type questions or comments in the chat 

window now, or email them to: 

DLAEnvPC@dla.mil.

• We will respond to questions as time allows 

now, or by email

• Comments will be compiled and provided to 

Pennsylvania DEP case manager along with 

the RIR/CP.

• Public review period is 90 days, ending 

March 16, 2022. 

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AUDIO ONLY:

To ask a question, Press *5 

on your phone. This will raise 

your hand. The moderator 

will indicate when your 

microphone has been 

enabled.
Thank You for Your Participation

• We appreciate you taking the time to participate 

in this public forum

• A copy of the minutes and presentation will be 

made available on the administrative record 

website:

– https://www.dla.mil/HQ/InstallationManagement/DoingB

usinessWithInstallationManagement/EnvironmentalDocu

ments/

• Updates to the clean-up efforts at DSCP and 

the Act 2 process will be posted at this website 

48