W912DR18R0055_-_Attachment__F_-_20171117_DSCR_FINAL_WorkPlanOU7_Remedial_Optimization.pdf

DEPARTMENT OF THE ARMY

BALTIMORE DISTRICT, CORPS OF ENGINEERS

10 S. HOWARD STREET

BALTIMORE, MD 21201

17-NOV-2017

CENAB-ENG-G

SUBJECT: FINAL OU-7 Remedial Design/Remedial Action Work Plan Addendum Defense Supply Center – Richmond Richmond, Virginia

EXECUTIVE SUMMARY AND BACKGROUND

The United States Army Corps of Engineers (USACE) Baltimore District (NAB) has prepared this Work

Plan Addendum to detail the proposed implementation of remedial optimization strategies. The proposed strategy is designed to enhance performance of the remedy in place by addressing dissolved phase chlorinated volatile organic compounds (cVOCs) detected in groundwater at Operational Unit‐7

(OU‐7), located within the above referenced facility. The proposed activities include:

Installation of additional injection wells;

Pre‐injection groundwater monitoring of select monitoring wells;

Targeted injection of electron donor in select wells; and

Post‐injection groundwater monitoring and sampling

OU‐7 is located near the southern boundary of the facility (Figure 1) and is focused solely upon groundwater. Within OU‐7, historic subsurface investigation activities have delineated three dissolved phase cVOC plumes which appear to originate near to the former locations of Fire Training Area (FTA)

Pits referenced, from east to west, as Pits 1, 2, and 3 (Figure 2). Groundwater flow within OU‐7 is predominately towards the south, south/southeast, and south/southwest. The apparent lateral extent of the dissolved phase plumes, based upon groundwater monitoring and analytical data from OU‐7 monitoring wells, is consistent with the groundwater flow direction.

Several remedial technologies have been implemented historically in OU‐7 including pilot testing of a soil vapor extraction (SVE) and dual phase extraction (DPE) remediation system (1995), pilot testing of density driven convection (DDC) (1999), removal of approximately 987 cubic yards of soil from apparent cVOC source areas (2004), pilot testing of enhanced in‐situ biodegradation through installation of a permeable reactive barrier (PRB) bio‐wall using organic mulch and sand (2007), and pilot testing of in‐ situ bioremediation utilizing injection of emulsified vegetable oil (EVO) (2009).

Based upon the results of the pilot testing, enhanced in‐situ bioremediation combined with institutional controls, was selected as the final remedy for OU‐7, per the record of decision (ROD) signed in 2012. In

2013 full‐scale injections of EVO were completed to address dissolved phase cVOCs with follow‐up injections completed in 2015. Post‐injection remedial monitoring indicates that some dissolved phase attenuation has occurred; however, the reductive dechlorination pathway for dissolved phase cVOCs at

CENAB‐ENG‐G 17‐NOV‐2017

OU‐7 appears to be incomplete, with decreasing to stable concentration trends in dissolved phase tetrachloroethene (PCE) and trichloroethene (TCE) and increasing to stable concentration trends in dissolved phase cis‐1,2‐dichloroethene (cis‐1,2‐DCE) and vinyl chloride (VC).

Based upon the dissolved phase cVOC trends it is likely that anaerobic biodegradation of dissolved phase cVOCs is occurring; however, the available carbon from the injections completed in 2013 has been utilized resulting in limited continued dechlorination of PCE and TCE, which forms daughter products including cis‐1‐2DCE and VC. The current rate of daughter product formation exceeds the rate of biodegradation which is why increasing to stable trends are apparent in dissolved phase concentrations of cis‐1‐2DCE and VC.

Based upon the nature and distribution of dissolved phase cVOCs the injection of additional carbon substrate is likely to further enhance in‐situ biodegradation processes and allow for complete reductive dechlorination to occur. The following sections detail the proposed plan to optimize the OU‐7 remedial strategy through the targeted enhancement of in‐situ biodegradation through expansion of the injection well network and injection of additional carbon substrate to act as an electron donor.

Relating to the existing organic mulch and sand PRB Bio‐walls installed in 2007, a qualitative post‐ implementation evaluation of effectiveness will be completed to facilitate additional discussion and allow for strategic planning of future activities relating to the bio‐walls.

PRE‐INJECTION GROUNDWATER MONITORING

Prior to commencement of the injection activities a preliminary natural parameter groundwater monitoring event will be completed utilizing monitoring wells adjacent to each area planned for injection. The wells selected for monitoring will be adjacent to each planned injection zone with at least one well downgradient, one well upgradient, and two cross gradient wells (One in each direction) in each zone. The monitoring event will consist of groundwater elevation monitoring as well as in‐well monitoring of natural groundwater water quality parameters including DO, pH, conductivity, ORP, turbidity, and conductivity. These values will be compared against the post‐monitoring data collected at the conclusion of the injection event.

WELL INSTALLATION

Based upon the current lateral and vertical distribution of the dissolved phase plumes the installation of additional wells is necessary to expand the current injection well network to allow for adequate substrate distribution during injection. The USACE NAB Field Exploration Unit (FEU) will mobilize to the facility during the week of October 30, 2017 to install 12 additional injection wells within OU‐7. The approximate well locations are depicted on Figure 2.

Advancement of the wells will be completed utilizing either hollow stem auger or mud‐rotary drilling methods, dependent upon observed field conditions. The boreholes will be at least eight inches in diameter to facilitate installation of four inch diameter monitoring wells. During advancement, soils and drilling fluids will be containerized for later characterization and disposal.

Following advancement, each well will be constructed from the bottom‐up; with approximately 10 to 20 feet of four inch diameter 0.020‐inch slot stainless steel wire wrapped screen, followed by four inch diameter PVC casing to the ground surface. After initial installation, a FilPro #1 sand gravel pack will be emplaced in the annular space between the screen and borehole wall from the bottom of the borehole to approximately two feet above the top of the screen interval. Approximately two to four feet of bentonite chips will then be placed above the sand gravel pack and hydrated to form a seal. Once hydrated, the remaining annular space will be grouted via tremie pipe using a bentonite slurry to within two feet of the ground surface. Surface completions for the wells will consist of a lockable gripper plug fitted to the top of the casing and bolt‐down flush mount manholes, constructed within two‐square‐foot concrete pads.

REMEDIAL INJECTIONS

Given the nature, extent, and concentration trends associated with the OU‐7 dissolved phase cVOC plume it is apparent that long‐term availability of donor is a limiting factor for prolonged enhanced in‐ situ bioremediation at this site. In order to ensure rapid restart of reductive dechlorination processes along with provision of a long‐lasting donor a proprietary food‐grade micro emulsion was selected for injection. The micro emulsion selected is LactOil®, produced by JRW Bioremediation, LLC (JRW). The emulsion consists of 43% highly bio‐available Ethyl Lactate combined with 43% long‐lasting EVO combined with an emulsifier and water. The following section is excerpted from a technical white‐paper provided by JRW, which describes the unique formulation and properties of LactOil®:

“LactOil® soy microemulsion is a patented emulsified vegetable oil substrate that is comprised of an isotropic thermodynamically stable liquid system designed to achieve superior subsurface distribution while promoting highly efficient microbial metabolism for the biodegradation of chlorinated organics and other anaerobically degradable contaminants. The thermodynamic stability of LactOil® allows the submicron emulsion particles, or micelles, to move throughout the soil pores for periods of time far exceeding those of standard emulsions. Laboratory tests performed at the University of Illinois suggest that the submicron micelles formed from LactOil® may remain present in the subsurface for time periods exceeding 6 months. This stability results in more complete distribution of the vegetable oil component throughout the soil and groundwater matrix through diffusion and advection for more uniform and effective treatment of the contaminated zone.

LactOil® also incorporates lactate as part of the micelles within the emulsion matrix. Sodium lactate is routinely used as a primary substrate to quickly promote microbial metabolism and is usually added in the field to standard emulsions to establish an initial chemically reduced environment. With standard emulsions, this leads to very rapid initial microbial growth that is not sustained after the sodium lactate has been consumed. In contrast, the lactate incorporated into LactOil® is released as the emulsion particles break enabling the system to maintain highly efficient microbial metabolism over long periods of time when compared to standard emulsified vegetable oil substrates.

This use of microemulsion chemistry to produce a substrate that combines better distribution and sustained highly efficient metabolism for anaerobic bioremediation has led to the issuance of patent

7,785,468 by the United States Patent Office.”

The LactOil solution will be prepared for injection by mixing batches above grade with water prior to injection. Connections and piping associated with the mixing will be periodically inspected to ensure integrity. A pump will then be used to inject the micro emulsion LactOil solution, under limited pressure

(less than 30 psi), through a manifold system; injecting into multiple wells within an area during each batch. During injection, periodic monitoring will be completed of groundwater levels in adjacent monitoring wells, along with visual inspection of any nearby storm water lines, slopes with potential for seepage, and wetlands. If injected product is observed at grade then injection operations will be temporarily suspended while subsurface pressure dissipates. Once dissipated, injection will resume under a lower pressure to ensure that surficial breakthrough does not occur.

Additionally, to address issues with mobility and distribution of the more viscous long‐term donors, for areas of relatively low dissolved phase cVOCs, the use of Sodium Lactate is proposed. Sodium lactate is readily bioavailable and can result in rapid dechlorination; however, typically, due to its high bioavailability, its persistence in the subsurface is significantly reduced. Therefore, for areas where

Sodium Lactate injection is proposed, the injectate will be gravity fed into the screen interval of each selected well, allowing for persistent in‐situ concentrations to be maintained.

A series of calculations have been completed based upon residual saturation and volume necessary to achieve effective distribution of injectates. Below, in Table 1, is a summary of the target injection products and volumes determined as part of this calculation for each area and well within OU‐7. Target wells for injection include existing injection wells, which were redeveloped in August 2017, as well as injection through the new proposed injection wells detailed above.

Table 1 – Proposed Locations, Injectates, and Volumes for Injection

Pit ID Plume Area

Number of

Wells in

Area

Proposed

Injectate

Pore

Volume

(Gallons)

Total

Injected

Fluids

(Gallons)

Injected

Water

(Gallons)

Injectate

(Gallons) Well ID

New

Well

Total

Injected

Fluids

(Gallons)

Injected

Water

(Gallons)

Injectate

(Gallons)

INJ‐200 Y 4881 4518 363

INJ‐201 Y 4881 4518 363

Downgradient

Area 1 LactOil 20196 5049 4767 282 INJ‐202 Y 5049 4767 282

INJ‐203 Y 5386 5085 301

INJ‐204 Y 5386 5085 301

INJ‐205 Y 5386 5085 301

INJ‐132 N 2020 1907 113

INJ‐133 N 2020 1907 113

INJ‐157 N 5049 4861 188

INJ‐158 N 5049 4861 188

INJ‐159 N 5049 4861 188

Lower Source 1 LactOil 20196 5049 4767 282 INJ‐206 Y 5049 4767 282

INJ‐207 Y 260 0 260

INJ‐163 N 260 0 260

INJ‐164 N 260 0 260

INJ‐165 N 260 0 260

INJ‐208 Y 5330 5032 297

INJ‐209 Y 5330 5032 297

INJ‐210 Y 5330 5032 297

INJ‐134 N 2284 2157 127

INJ‐135 N 2284 2157 127

INJ‐136 N 2284 2157 127

INJ‐137 N 2284 2157 127

INJ‐151 N 2284 2157 127

INJ‐152 N 2284 2157 127

INJ‐153 N 2284 2157 127

INJ‐154 N 260 0 260

INJ‐155 N 260 0 260

INJ‐156 N 260 0 260

INJ‐211 Y 260 0 260

Source Area 10 LactOil 127908 30192 1785

Downgradient

Area

Sodium

Lactate

NA 1040 0 1040

31977

NA

9035 726

Area Target Quantities Target Quantities by WellArea Data

20196 19069 1127

MidPlume 3 LactOil 60588 15147 14583

780 0 780

Source Area 2 LactOil 39046

Upper Source 5 LactOil 80784

Downgradient

Area

Sodium

Lactate

Figures 3 and 4 include a depiction of the approximate well locations and areas for injection. Below, Figure 5 depicts, in cross‐section, a generalized conceptual model of OU‐7 geology and a brief synopsis of the general approach for the injection optimization testing.

POST INJECTION MONITORING

Approximately one month following completion of the injections a groundwater monitoring and sampling event will be completed of select wells. The select wells will match those monitored as part of the pre‐injection monitoring event. Samples will be collected following the United States Environmental

Protection Agency (USEPA) – Low Stress Purging and Sampling Procedures for the Collection of

Groundwater Samples from Monitoring Wells. Per the sampling procedure, groundwater water quality parameters will be monitored during purging of groundwater and samples will be collected once parameter stabilization occurs. The natural parameters will be collected utilizing a flow through cell;

parameters will include DO, pH, conductivity, ORP, turbidity, and conductivity. These values will be compared against the pre‐monitoring data collected in advance of the injection event to evaluate preliminary extent of the injection effect on aquifer geochemistry.

SCHEDULE

A schedule is presented below which includes the work proposed in this plan. USACE NAB G&I and FEU are mobilizing to the facility during the week of November 27, 2017 to begin remedial injections and during the week of December 6 to begin installation of the additional injection wells.

Figure 5

ENCLOSURES:

FIGURES

Figure 1 – DSCR Operable Units

Figure 2 – OU‐7 Remedial Technologies and Pilot Tests (ARCADIS)

Figure 3 – New and Existing Wells to be Utilized in Optimization Test

Figure 4 – OU‐7 Well Network

Defense Supply Center Richmond ‐ OU7 Remedial Optimization

Task Description Start Date End Date Duration

(Weeks)

‐O ct

6‐ N ov

‐N ov

‐N ov

‐N ov

4‐ D ec

‐D ec

‐D ec

‐D ec

1‐ Ja n

8‐ Ja n

‐J an

‐J an

‐J an

5‐ Fe b

‐F eb

‐F eb

‐F eb

5‐ M ar

‐M ar ‐M ar ‐M ar 2‐ A pr

9‐ A p

‐A pr

Injection Well Redevelopment and Installation 28‐Aug‐17 22‐Dec‐17 16

Well Redevelopment 28‐Aug‐17 24‐Sep‐17 4

Well Install 6‐Dec‐17 22‐Dec‐17 3

Baseline Groundwater Monitoring for Select Wells 27‐Nov‐17 3‐Dec‐17 1

Preliminary Groundwater Monitoring Event 27‐Nov‐17 3‐Dec‐17 1

Remedial Implementation 30‐Oct‐17 14‐Jan‐18 10

Preparation for Injection Event, onsite manifold construction, e 30‐Oct‐17 5‐Nov‐17 1

Subsurface Injection of EVO/Lactate 27‐Nov‐17 14‐Jan‐18 7

Post‐Remedial Groundwater Monitoring for Select Wells 5‐Feb‐18 11‐Feb‐18 1

Post‐Remedial Groundwater Monitoring and Sampling Event 5‐Feb‐18 11‐Feb‐18 1

Remedial Effectiveness Evaluation 22‐Jan‐18 18‐Feb‐18 4

Preliminary Evaluation 19‐Feb‐18 4‐Mar‐18 2

Interim Memorandum on Preliminary Remedial Evaluation 26‐Feb‐18 4‐Mar‐18 1

Detailed Evaluation 5‐Mar‐18 18‐Mar‐18 2

Reporting 12‐Mar‐18 22‐Apr‐18 6

Drafting of Remedial Optimization Test Report 12‐Mar‐18 1‐Apr‐18 3

Draft Report Review and Comment 2‐Apr‐18 15‐Apr‐18 2

Final Report Submittal 16‐Apr‐18 22‐Apr‐18 1

Summary Task

Task To Be Completed

Holidays, No Task Scheduled

Defense Supply Center Richmond Operable Units

Figure

INSET

Virginia h

Defense Supply Center Richmond

NO NAME CREEK

KINGSLAND CREEK

0 1,200600 Feet

DEFENSE SUPPLY

CENTER RICHMOND

RICHMOND, VIRGINIA

DATE

CHKD

DRAWN

PROJ. NO.

Crystal Hardin

60225754

Manish Joshi

JAM

ES R

IVE

R

OU7 GROUNDWATER

OU6 GROUNDWATEROU1

OU10

OU11

OU12

OU13

OU2

OU3

OU4

OU5

OU8 GROUNDWATER

OU9

PX GAS

Legend Saprolite WBU Groundwater Contamination Lower WBU Groundwater Contamination Upper WBU Groundwater Contamination

K

1/21/2014

E:\DSCR\Figures\OU7_Janaury_2014\Figure_1-1_DSCR_Operable_Units.mxd

! A! A

! A

! A! A

! A

! A! A! A! A

! A! A! A

! A

! A

! A

! A

! A

! A

! A

! A ! A

! A

! A

! A

! A

! A

! A

! A

! A

! A

! A

! A

! A

! A

! A

! A

! A

! A ! A

! A

@A

@A

@A

@A

@A@A@A@A

@A@A@A@A@A

@A@A@A@A@A

@A@A@A@A@A

@A@A

@A@A@A@A

@A

@A

@A

@A @A

@A

@A

@A

@A

@A

@A

@A

@A @A

@A

@A

@A

@A

@A

@A @A @A @A

@A

@A @A

@A

@A

@A

@A

@A

@A

@A @A

@A

@A

@A

@A

@A

@A

@A

@A @A

@A

@A @A

@A

@A

@A

@A

@A

@A

@A

@A

@A

@A

@A

@A

@A

@A

@A

@A

@A

@A

@A

@A @A@A

@A @A@A

@A @A

@A

@A

@A

@A @A@A

@A

@A

@A

@A

@A @A

@A

@A@A

@A@A

@A@A

@A@A

@A@A @A

@A

@A

@A @A

@A @A @A

@A @A

@A @A

@A

@A

@A

@A

@A

@A

@A @A

@A

@A

@A

@A

! A! A

! A

! A! A

! A

! A! A! A! A

! A! A! A

! A ! A

! A

! A

! A

! A

! A

! A

! A

! A ! A

! A

! A

! A

! A

! A

! A

! A

! A

! A

! A

! A

! A

! A

! A

! A

! A

! A ! A

! A

@A

@A

@A

@A

@A@A@A@A

@A@A@A@A@A

@A@A@A@A@A

@A@A@A@A@A

@A@A

@A@A@A@A

@A

@A

@A

@A @A

@A

@A

@A

@A

@A

@A

@A

@A @A

@A

@A

@A

@A

@A

@A @A @A @A

@A

@A @A

@A

@A

@A

@A

@A

@A

@A @A

@A

@A

@A

@A

@A

@A

@A

@A @A

@A

@A

@A @A

@A

@A

@A

@A

@A

@A

@A

@A

@A

@A

@A

@A

@A

@A

@A

@A

@A

@A

@A

@A @A@A

@A @A@A

@A @A

@A

@A

@A

@A @A@A

@A

@A

@A

@A

@A @A

@A

@A@A

@A@A

@A@A

@A@A

@A@A @A

@A

@A

@A @A

@A @A @A

@A @A

@A @A

@A

@A

@A

@A

@A

@A

@A @A

@A

@A

@A

@A

D M

W -3

3B

P

IT

P

IT

P

IT

F

O R

M E

R A

B O

V E

G R

O U

N D

F U

E L

S T

O R

A G

E T

A N

K

S E

C O

N D

A R

Y C

O N

T A

IN

M

E N

T B

E R

M

C M

T

C M

T

C M

T

C M

T

C M

T

C M

T

C M

T

D M

W

E

M W

F

TA

M W

F

TA

M W

F

TA

M W

F

TA

B

M W

F

TA

B

M W

F

TA

2A

M W

F

TA

B

M W

F

TA

B

M W

C M

T

C M

T

C M

T

C M

T

D M

W

B

M W

F

TA

M W

F

TA

M W

F

TA

M W

F

TA

M W

F

TA

M W

F

TA

M W

F

TA

M W

F

TA

M W

M W

M W

M W

P W

F

TA

A E

H A

D G

A E

H A

D G

A E

H A

D G

A E

H A

D G

C M

T

C M

T

C M

T

C M

T

C M

T

C M

T

D M

W

A

D M

W

A

D M

W

A

D M

W

A

D M

W

A

D M

W

A

D M

W

A

D M

W

A

D M

W

A

D M

W

A

D M

W

A

E B

F

S

M W

F O

S

M W

F O

S

M W

F O

S

M W

F

TA

M W

F

TA

M W

F

TA

M W

F

TA

M W

F

TA

M W

F

TA

M W

F

TA

M W

F

TA

M W

F

TA

M W

F

TA

M W

F

TA

A

M W

F

TA

M W

F

TA

M W

F

TA

M W

F

TA

M W

F

TA

M W

P A

H

M W

M W

M W

M W

M W

M W

M W

M W

M W

M W

M W

M W

M W

M W

M W

M W

M W

M W

M W

M W

M W

M W

M W

6 M

W

M W

M W

M W

M W

M W

M W

M W

M W

M W

M W

M W

M W

M W

50 M W

M

W

M W

53 M W

M W

M W

M W

M W

M

W

M W

M W

M W

M W

M W

M

W

M W

M

W

M W

M

W

M W

M W

M W

M

W

M W

M W

81 M W

M W

M

W

M W

M W

M W

M W

M W

M W

M W

M W

M

W

M W

M

W

M W

M W

M W

P 1B

W A

P 1B

W A

P 1B

W A

P 1B

W B

P 1B

W B

P 1B

W B

P 2B

W A

P 2B

W B

P Z

P Z

P Z

P Z

P Z

P Z

P Z

P Z

P Z

P W

F

TA

C M

T

IN

J1

28 IN

J1

IN

J1

IN

J1

IN

J1

IN

J1

IN

J1

IN

J1

IN

J1

36IN

J1

IN

J1

IN

J1

IN

J1

IN

J1

IN

J1

IN

J1

IN

J1

IN

J1

IN

J1

55IN

J1

IN

J1

IN

J1

IN

J1

IN

J1

IN

J1

IN

J1

IN

J1

IN

J1

64IN

J1

IN

J1

IN

J1

IN

J1

IN

J1

IN

J1

IN

J1

IN

J-

IN

J-

IN

J-

IN

J-

IN

J-

IN

J-

IN

J-

IN

J-

IN

J-

IN

J-

IN

J-

IN

J-

IN

J-

IN

J-

B ld g . 1

B ld g

W a re h o u se

B ld g

O S

-2

O S

-1

B ld g

B ld g

B ld g

A re a

A re a

A re a

A re a

A re a

G Rd

Q R d

P R d

O R d

D e fe n se G e n e ra l

M R d

KINGSLAND CREEK

3674000

3674000

3674500

3674500

3675000

3675000

D at a S o ur ce s:

A E

C O

M

G

IS

D at a;

E S

R I, A rc

G

IS

O n lin e

A ria l I m ag er y

C oo rd in a te

S ys te m

V

A S ta te

P la n e, S ou th D at u m

N A

D

U ni ts

F ee t

F e e t

L eg e n d

U .S

G o ve rn m e n t P ro p e rt y

O U

-7

B io w a ll L o ca tio n

F ir e T ra in in g

A re a P it Lo ca tio n

S

V E

/D P

E P ilo t T e st

W e ll (1

D D

C P ilo t T e st

A re a

D

D C

W e ll (1

9)

E V

O I n je ct io n A re a

Ja n u a ry

In -s itu B io re m e d ia tio n

A re a

M o n it o ri n g

W el ls

Lo w e r W

B U

I n je ct io n

W e ll

U p p e r

W B

U I n je ct io n W e ll

! A B ed ro ck M o n ito rin g W e ll

! A S ap ro lit e

M o n ito rin g

W e ll

@ A Lo w e r W

B U

M o ni to ri ng

W e ll

M o n ito ri n g W e ll, W B

U U n kn o w n

Lo w e r W

B U

P ie zo m e te r

P ie zo m e te r, W B

U U nk n o w n

T C

E P lu m e s

LW

B U

(S p ri n g μ g /L μ g /L μ g

/L μ g /L B e dr oc k W e ll

ID

S a pr ol ite W e ll

ID

Lo w er W

B U

W e ll/ P

Z

ID

U nk n ow n W

B U

W el l/P Z

I D

U pp er W

B U

W e ll

ID

G ro un dw at e r E le va tio n

M W

M W

M W

C M

T

D e fe n s e

S u p p ly C en te r R ic h m o n d

R ic h m o n d

V A

³ F ig u re

O U

R em ed ia l

T ec h n o lo g ie s an d P il o t T es ts

.0

O U

-7 S

V E

/D P

E P il o t T e s t (1

T h e t e st w a s co n d u ct e d in A u g u st a n d S e p te m b e r

B a se d o n t h e r e su lts th e

D P

E t e ch n o lo g y w a s re co m m e n d e d fo r co n si d e ra tio n a s p a rt o f a n o ve ra ll re m e d ia tio n p la n

D e n s it y

D ri v e n C o n v e c ti o n

D

D C

P il o t Te s t

(1

A p ilo t sy st e m c o n si st in g o f o n e D

D C w e ll, n in e n e st e d p ie zo m e te rs a n d a n a b o ve g ro u n d p re ss u ri ze d a ir s u p p ly s ys te m w e re u se d t o t e st t h e e ffe ct iv e n e ss o f

D D

C in r e d u ci n g c o n ce n tr a tio n s o f C

O C s in g ro u n d w a te r a n d t o e va lu a te t h e f e a si b ili ty o f u si n g D

D C a s a f u ll sc a le r e m e d ia l t e ch n o lo g y.

T h e s ys te m w a s o p e ra te d f ro m

D e ce m b e r t o

J a n u a ry

In t h is t e ch n o lo g y, a ir in je ct e d a t th e b o tt o m o f th e

D D

C w e ll, r is e s in a s e ri e s o f sl u g s cr e a tin g t h e f lo w o f w a te r th ro u g h t h e

D D

C w e ll, a n d u lti m a te ly le a d in g t o a c ir cu la tio n o f w a te r w ith in t h e a q u ife r su rr o u n d in g t h e w ll.

D is so lv e d v o la til e c o m p o u n d s w o u ld b e s tr ip p e d o ff t h e g ro u n d w a te r a s th e w a te r flo w s th ro u g h t h e w e ll a n d t h e o xy g e n a te d g ro u n d w a te r ci rc u la te d t h ro u g h th e a q u ife r w o u ld s tim u la te b io re m e d ia tio n w ith in t h e c o n ta m in a te d a q u ife r.

R e su lts o f th e t e st s u g g e st e d t h a t D

D C w o u ld b e a f e a si b le r e m e d ia l o p tio n f o r th e s ite

I t sh o w e d t h a t

D D

C c a n r e d u ce d is so lv e d V

O C c o n ce n tr a tio n s a t le a st f e e t a w a y in d a ys o f o p e ra tio n

O U

-4 T im e

C ri ti c a l

R e m o v a l A c ti o n (2 c u b ic y a rd s o f so il w e re e xc a va te d in o rd e r to r e m o ve c o n ta m in a n t m a ss f ro m t h e v a d o se z o n e a t

O U

O U

-7 E n h a n c e d I n -s it u

B io d e g ra d a ti o n T re a ta b il it y T e s ts (2

T h e y w e re im p le m e n te d in t h e

P its a n d a re a s o f O

U

L o w e r W

B U

T h e se t e st s co n si st e d o f p la ce m e n t o f tw o

P R

B s o r tr e a tm e n t w a lls b io w a lls co n ta in in g o rg a n ic m u lc h a n d s a n d d o w n g ra d ie n t o f F

T A

P it a n d

F

TA

P it s o u rc e a re a s.

A s e p a ra te in

-s itu b io re m e d ia tio n t re a ta b ili ty t e st w a s co n d u ct e d in t h e F

TA

P it a re a in

A p ri l 2

A p p ro xi m a te ly

,1 g a llo n s o f p e rc e n t

(v o lu m e /v o lu m e

E

V O w a s in je ct e d in a n a re a o f e le va te d c h lo ri n a te d s o lv e n t co n ce n tr a tio n in t h e

O U

L o w e r

W B

U

O U

-7 M

N A

LT

M (2 p re se n

t) R

O D f o r O

U w a s si g n e d in

T h e f in a l r e m e d y fo r

O U c o n si st e d o f in -s itu b io re m e d ia tio n c o n si st in g o f E

V O in je ct io n s in s o u rc e a re a s a n d d o w n g ra d ie n t h ig h c o n ce n tr a tio n a re a s, M

N A a n d L o n g T e rm

M o n ito ri n g a n d

I n st itu tio n a l C o n tr o ls

O U

I n -S it u

B io re m e d ia ti o n a n d I

C s

(2 p re se n t)

A s p a rt o f th e f in a l r e m e d y, in -s itu b io re m e d ia tio n t h a t in cl u d e d in je ct io n s o f

E V

O w a s in iti a te d in t o t re a t

C V

O C s in t h e lo w e r W

B U a t th e s o u rc e a re a a n d d o w n g ra d ie n t p lu m e s.

I n st itu tio n a l c o n tr o ls w e re a ls o e st a b lis h e d t o p re ve n t e xp o su re t o O

U -7 g ro u n d w a te r.

IN

J in ch fe et

P ro p o s e d W e lls

P ro po se d

In je ct io n W el l -

N et w or k

E xp an si on by A

C E

P ro po se d

In je ct io n W el l -

R em ed y

O p tim iz at io n

A

A

A

A

A

A

A

A

A

A

A A

A A

A A

A A

A

A A

A

A A

A

A A

A

A

A

A

A

A

A A

A

A

A A A

A

A

A

AA

A A

A

A

A

A A

A

A

A A

A

A

A

A

AA

A

A

A

A A

A A

A A

A

A

A

A

A

A

A

A

AA

A

A

A

AA

A

A

AA

A

A

A

AA

A

AA

AA

A

AA

A

A

A

A

A

AA

AA

AA

A

AA

A

A

AA

A

A

A

A

A

A

AA

A

AA

A

A A

A

A

AA

A A

A

AA

A

A

A

A

A

A

A

A

A

A

A

A

A

A

PZ-2

PZ-9

MW40

PZ-7

PZ-8

PZ-4

PZ-3

PZ-1

PZ-5

PZ-6

MW-89

MW-90MW-91

MW-93MW-92

MW-98

MW-40

MW-85MW-55

MW-50

MW-53

MW-54

MW-74MW-75

MW-76MW-77

MW-79MW-78

MW-81

MW-80

MW-83

MW-82MW-84 MW-88

MW-87MW-86

MW-65MW-42

MW-64

MW-71

MW-72MW-69

MW-60MW-61

MW-59

MW-68

MW-38

MW-57

MW-56

MWFTA9

MWFTA1

MWPAH1

MW-143MW-128

MW-142

MW-127

MW-118

MW-117

MW-116

MW-141

MW-188

DMW27A

MW-140

MW-139

MWF0S3

MWF0S4

MW-125

MWF0S2

MW-119

MW-145

CMT-18

MW-144

MW-120

DMW26A MW-122

MW-121

DMW25A

CMT-25

MW-148

MW-147

MWFTA3

MW-149

MWFTA5

MWFTA6

PWFTA1

CMT-20 MW-150

DMW13AMW-123

CMT-22

MWFTA10

MWFTA11

MWFTA27

MWFTA26

MWFTA12

DMW-22ADMW-21A

DMW-20A

P1BWB70

DMW-19A

AEHADG9

P1BWA66

DMW-35A

DMW-13A

INJ-211

INJ-210

INJ-209

INJ-208

INJ-206

INJ-205

INJ-204

INJ-203

INJ-202

INJ-201INJ-200

INJ-163

INJ-159

INJ-157

INJ-156

INJ-153

INJ-137

OU7 WELL NETWORK

DSCR, VA

D oc um en t P at h:

O

:\P R

O

JE

C

TS

\D S

C R ic hm on d\

O U

-7 \G

IS

\D

S C

R _O

U 7_

O pt im iz at io n1 .m xd D at e:

0/

/2

0 150 300 450 60075 Feet®

Legend Monitoring Well Network

A

A Existing Injection Wells

A Injection Wells To Install

LWBU Spring 2017 Plumes

PCE, 5

PCE, 50

PCE, 500

PCE, 5000

TCE, 5

TCE, 50

TCE, 500

TCE, 5000

SWBU Spring 2017 Plumes

PCE, 5

PCE, 50

TCE, 5

TCE, 50

FIGURE 4