1

GROUNDWATER REMEDIATION OF A HIGHLY CONTAMINATED

BEDROCK SITE

- The Oxygen Infusion Phase -

J. MorrowD. Side

By:

2

Gas station/auto repair 1940s-1999

Heavy residential/commercial area in SE Pennsylvania

Eight USTs removed between 1994-1999

Catastrophic petroleum hydrocarbon release, 1995

Surrounding properties include:

• Commercial & Industrial sites with water supply wells

• Residential properties with water supply wells

• PA Turnpike

3

Location

1273 DeKalb Pike

USGS

4

Bedrock

•Begins 7-10’ below ground surface

•Sandstone w/interbedded shale

Three saturated zones

•15’ to 50’

•60 to 75’

•80’ to 93’?

Groundwater flow, north w/components west and south

5

Hydraulic conductivity - 600’/day, avg.

Water table elevation changes 8 feet

Gradient - 0.09 (average)

Velocity - 0.2 to 2 ft/day

Direction - mixed, complex

Likely multiple source areas of contamination

6

1995-’98 - Site characterization

1995-’02 - LNPL removal

Late ’98 - Install pump/treat remediation w/bioreactor

Early ’02 - Install second bioreactor using on-site WSW

October ’02 - Installed 2 iSOCs in on-site monitoring wells. A third iSOCs added Feb. ‘03

October ’03 - installed 6 infusion wells w/iSOCs upgradient of plume

• Total of 9 iSOCs

7

iSOC pilot phase was encouraging.

12 months after initiating the pilot phase, 6 new infusion wells were added employing a total of 9 iSOC O2 infusion points.

Source area contaminant reductions have been excellent both for BTEX and MTBE.

As cleanup has progressed, selective iSOC infusion points have been relocated to optimize contaminant reductions.

8

Initial pump/treat system used extraction wells within the source area. Results were only modestly successful due to low hydraulic conductivity.

Installation of second pump/treat bioreactor used a water supply well (WSW) as the extraction well; pumping rates between 5 and 10 gpm were achieved. Good hydraulic control was obtained and excellent treatment of off-site contamination. Source area contamination was only marginally affected.

Supplemental remediation for onsite contamination was indicated. iSOC was selected initially for a pilot study.

9

Air as source 7-10 mg/l

Pure O2 (when diffused) 18-20 mg/l

O2 via iSOC

42 mg/l @ 5’ head

111 mg/l @ 50’ head

10

What it looks like

Hydrophobic, micro porous O2 delivery system

Extraordinary surface area, 7000 m2/m3

Rugged materials and construction

11

12

PA Bedrock SiteO2 Control Systems For 9 iSOCS

13

PA Bedrock Site O2

Storage

14

Field Tests

• pH, DO, ORP, NO31-, PO4

3-

Laboratory

• BOD5, TOC, COD

• Heterotrophic Plate Counts

• enzymes

• COCs

15

COCs and field tests - monthly for 18 months

Biochemical parameters

• BOD, TOC, COD, HPC - quarterly, selective wells

Enzymes - two rounds, selective wells

16

Final installation of iSOC coincided with peak drought in SE Pennsylvania

Subsequently it started raining, groundwater elevations increased 6’ to 10’

Some MWs displayed dramatic increases in COCs

17

B U R TS AU TOR EP AIR

S H ED

CARWAS H

1265 DEK AL B P IK E

1257 DEK ALB P IK E

P ROP E RT Y L IM IT

S H ED

WAS T EOIL

FO RM ER D IESE L D ISPENS ER

FO RM ER D IESE L U STFORM ERKIOSK

FO R M ER PU M P ISLAN DS

DEK ALB P IK E (ROU TE 202)

M W -1

M W -2

M W -3

M W -4

M W -5

M W -6

M W -7

M W -8

M W -9

M W -10

W SW -A

W SW -B

W SW -C

M W -11

M W -12

M W -13

M W -14

STREAMP

A T

UR

NP

IKE

G W FLO W

DRINKINGH2O W ELLS

G W FLO W

1.0 ACRE SITE

PA Bedrock Site with Surrounding Features

18

260.23277.14

263.60

274.69

267.23

266.17

279.83 274.27

267.42

256.65

255.99 257.11

218.26

266.65

251.01

270.42

257.61

M W -1M W -2

M W -3

M W -4

M W -5

M W -6

M W -7 M W -8

M W -9

M W -10

M W -11 M W -12

M W -13

M W -14

W SW -A

W SW -B

W S W -C

259.86276.86

260.49

271.60

266.83

265.50

275.84 261.75

264.10

256.80

257.03 257.66

258.73

266.91

250.72

265.69

257.52

M W -1M W -2

M W -3

M W -4

M W -5

M W -6

M W -7 M W -8

M W -9

M W -10

M W -11 M W -12

M W -13

M W -14

W S W -A

W SW -B

W SW -C

B U R T'S A U TOR E PA IR

CA R W AS H

1265 DE

KA

LB P

IKE

MA

SO

NA

RY

BU

ILDIN

G

1257 D EK ALB P IK E

DE

KA

LB

PIK

E - R

OU

TE

202

PR

OP

ER

TY

LIMIT

SH

ED

B UR T'S A U TOR EP AIR

CA R W AS H

1265 DE

KA

LB P

IKE

MA

SO

NA

RY

BU

ILDIN

G

1257 DE KA LB P IKE

DE

KA

LB P

IKE

- RO

UT

E 2

02

PR

OP

ER

TY

LIMIT

SH

ED

P A B E D R O C K S I T E

S tatic C on dtion s( A pr il 2 0 0 2 )

P u m p/T r eat C on d it ion s( S eptem ber 2 0 0 3 )

G r ou n dw ater F low

G ro u n d w a ter flow

19

Isoconcentration maps

DO plume progression

Selective BTEX, MTBE trends

Selective hydrograph

20

MW-1

MW-2

MW-3

MW-4

MW-5

MW-6

MW-7

MW-8

MW-9

MW-10

WSW-A

WSW-B

WSW-C

MW-11

MW-12

MW-13

MW-14

IW-1

IW-2

IW-3

IW-4

IW-5IW-6

613.6

4.35

0

0

0

0

0

0

2489

0

390.2

0

0

0

0

0.4

0

13866

0

0

0

4.440

MW-1

MW-2

MW-3

MW-4

MW-5

MW-6

MW-7

MW-8

MW-9

MW-10

WSW-A

WSW-B

WSW-C

MW-11

MW-12

MW-13

MW-14

IW-1

IW-2

IW-3

IW-4

IW-5IW-6

3588

ND

ND

14

1

14

3420

539

19364

ND

633

ND

4.4

ND

ND

10005

ND

56

44

83

ND

161442

MW-1

MW-2

MW-3

MW-4

MW-5

MW-6

MW-7

MW-8

MW-9

MW-10

WSW-A

WSW-B

WSW-C

MW-11

MW-12

MW-13

MW-14

495

5733

0

208

0

0

10581

8374

24100

0

649

0

0

0

0

8188

50

BURTS AUTOREPAIR

SHED

CARWASH

1265 DEKALB PIKE

1257 DEKALB PIKE

PROPERTY LIMIT

SHED

WASTEOIL

BURTS AUTOREPAIR

SHED

CARWASH

1265 DEKALB PIKE

1257 DEKALB PIKE

PROPERTY LIMIT

SHED

WASTEOIL

BURTS AUTOREPAIR

SHED

CARWASH

1265 DEKALB PIKE

1257 DEKALB PIKE

PROPERTY LIMIT

SHED

WASTEOIL

BTEX MapsO2 Infusion Phase

9 months, 3 iSOCs +

BaselineZero iSOCs

20 months, 3 iSOCs +14 months, 6 iSOCs

800 ppb

5,000 ppb

10,000 ppb

20,000 ppb

August 2003

August 2002

July 2004

3 months, 6 iSOCs

21

M W -1

M W -2

M W -3

M W -4

M W -5

M W -6

M W -7

M W -8

M W -9

M W -10

W SW -A

W SW -B

W SW -C

M W -11

M W -12

M W -13

M W -14

IW -1

IW -2

IW -3

IW -4

IW -5IW -6

2000

368

12000

33

109

19.4

12800

235

5780

8

456

N D

18.5

N D

N D

2910

N D

48.4

451

1780

27

14103.2

M W -1

M W -2

M W -3

M W -4

M W -5

M W -6

M W -7

M W -8

M W -9

M W -10

W SW -A

W SW -B

W SW -C

M W -11

M W -12

M W -13

M W -14

1,030

3,770

14,300

646

156

4

6,290

12,500

17,100

N A

8,292

N D

1.38

N D

N D

6,570

3,000

71

1060

10200

0

0

0

9570

7

1880

0

261

0

0

0

0

0

0

8350

1980

17

0

150

M W -1

M W -2

M W -3

M W -4

M W -5

M W -6

M W -7

M W -8

M W -9

M W -10

W SW -A

W SW -B

W SW -C

M W -11

M W -12

M W -13

M W -14

IW -1

IW -2

IW -3

IW -4

IW -5IW -6

B U RT S AU TOREP AIR

S H ED

C ARWAS H

1265 DEK AL B P IK E

1257 DEK AL B P IK E

P ROP ERT Y L IM IT

S H ED

WAS T EOIL

B U RT S AU TOREP AIR

S H ED

CARWAS H

1265 DEK AL B P IK E

1257 DEK AL B P IK E

P ROP ERT Y L IM IT

S H ED

WAS T EOIL

B U R TS AU TOREP AIR

S H ED

CARWAS H

1265 DEK AL B P IK E

1257 DEK ALB P IK E

P R OP ER T Y L IM IT

S H ED

WAS TEOIL

FO R M ER D IES EL D ISP EN SER

FO R M E R D IE SE L U STF O R M ERKIO SK

F O R M ER P U M P IS LA N D S

500 ppb

2,000 ppb

8,000 ppb

12,000 ppb

M TBE M apsO 2 Infusion Phase

B aselineZero iSO C s

9 m onths, 3 iSO C s +3 m onths, 6 iSO C s

20 m onths, 3 iSO C s +14 m onths, 6 iSO C s

August 2003

July 2004

August 2002

22

MW-1

MW-2

MW-3

MW-4

MW-5

MW-6

MW-7

MW-8

MW-9

MW-10

WSW-A

WSW-B

WSW-C

MW-11

MW-12

MW-13

MW-14

IW-1

IW-2

IW-3

IW-4

IW-5IW-6

0.7

46.3

7.4

0.2

7.2

5.5

42.8

0.6

1.9

0.5

0.8

1.8

6.8

0.30.5

MW-1

MW-2

MW-3

MW-4

MW-5

MW-6

MW-7

MW-8

MW-9

MW-10

WSW-A

WSW-B

WSW-C

MW-11

MW-12

MW-13

MW-14

IW-1

IW-2

IW-3

IW-4

IW-5IW-6

1.9

50.5

48.9

3.7

8.0

6.4

36.9

2.8

38.4

34.3

44.9

40.2

8.7

33.040.3

MW-1

MW-2

MW-3

MW-4

MW-5

MW-6

MW-7

MW-8

MW-9

MW-10

WSW-A

WSW-B

WSW-C

MW-11

MW-12

MW-13

MW-14

IW-1

IW-2

IW-3

IW-4

IW-5IW-6

1.4

42.0

42.7

44.3

1.3

40.1

1.4

1.2

0.8

7.4

41.7

44.2

42.9

6.0

1.57.5

Dissolved OxygenDO Plume Progression

BURTS AUTOREPAIR

SHED

CARWASH

1265 DEKALB PIKE

1257 DEKALB PIKE

PROPERTY LIMIT

SHED

WASTEOIL

FORMER DIESEL DISPENSER

FORMER DIESEL USTFORMERKIOSK

FORMER PUMP ISLANDS

BURTS AUTOREPAIR

SHED

CARWASH

1265 DEKALB PIKE

1257 DEKALB PIKE

PROPERTY LIMIT

SHED

WASTEOIL

FORMER DIESEL DISPENSER

FORMER DIESEL USTFORMERKIOSK

FORMER PUMP ISLANDS

BURTS AUTOREPAIR

SHED

CARWASH

1265 DEKALB PIKE

1257 DEKALB PIKE

PROPERTY LIMIT

SHED

WASTEOIL

FORMER DIESEL DISPENSER

FORMER DIESEL USTFORMERKIOSK

FORMER PUMP ISLANDS

10 ppm

20 ppm

30 ppm

40 ppm

50 ppm

1 monthw/3 iSOCs

16 months, 3 iSOCs +

9 months, 9 iSOCs

23 months, 3 iSOCs +16 months, 6 iSOCs

March 2003

December 2003 July 2004

23

PA BEDROCK SITE - MW3

OXYGEN INFUSION PHASE

MTBE & BTEX TRENDS, AVERAGE FOR QUARTER

0

5,000

10,000

15,000

20,000

25,000

30,000

Q2-02 Q3-02 Q4-02 Q1-03 Q2-03 Q3-03 Q4-03 Q1-04 Q2-04 Q3-04Sampling Period0

50

100

150

200

250

B T E X

M T B E

Baseline

Install 2 iSOCS

Install 3rd iSOC

Install 4-9 iSOCs

Pilot Phase Full Scale Phase

24

PA BEDROCK SITE - MW9

OXYGEN INFUSION PHASE

MTBE & BTEX TRENDS, AVERAGE FOR QUARTER

0

5,000

10,000

15,000

20,000

25,000

30,000

Q2-02 Q3-02 Q4-02 Q1-03 Q2-03 Q3-03 Q4-03 Q1-04 Q2-04 Q3-04

Sampling Period

MT

BE, p

pb

0

5,000

10,000

15,000

20,000

25,000

30,000

BTEX

, ppb

BTEX

MTBE

BaselineInstall 2 iSOCS Install

3rd iSOC

Install 4-9 iSOCs

Pilot Phase Full Scale Phase

25

0

2,000

4,000

6,000

8,000

10,000

12,000

14,000

16,000

Q2-02 Q3-02 Q4-02 Q1-03 Q2-03 Q3-03 Q4-03 Q1-04 Q2-04 Q3-04

Sampling Period

MTB

E, pp

b

0

2,000

4,000

6,000

8,000

10,000

12,000

BTEX

, ppb

BTEX

MTBE

BaselineInstall 2 iSOCS

Install 3rd

iSOC Install 4-9 iSOCs

Pilot Phase Full Scale Phase

PA BEDROCK SITE - MW7

OXYGEN INFUSION PHASE

MTBE & BTEX TRENDS, AVERAGE FOR QUARTER

26

0

2,000

4,000

6,000

8,000

10,000

12,000

14,000

16,000

18,000

Q1-03 Q2-03 Q3-03 Q4-03 Q1-04 Q2-04 Q3-04

Sampling Period

0

2,000

4,000

6,000

8,000

10,000

12,000

14,000

16,000

18,000

20,000

BTEX

MTBE

PA BEDROCK SITE - IW1

OXYGEN INFUSION PHASE

MTBE & BTEX TRENDS, AVERAGE FOR QUARTER

27

0

1,000

2,000

3,000

4,000

5,000

6,000

7,000

8,000

9,000

10,000

Q1-03 Q2-03 Q3-03 Q4-03 Q1-04 Q2-04 Q3-04

Sampling Period

0

2,000

4,000

6,000

8,000

10,000

12,000

14,000

16,000

18,000

20,000

BTEX

MTBE

PA BEDROCK SITE - IW2

OXYGEN INFUSION PHASE

MTBE & BTEX TRENDS, AVERAGE FOR QUARTER

28

0

500

1,000

1,500

2,000

2,500

3,000

Q1-03 Q2-03 Q3-03 Q4-03 Q1-04 Q2-04 Q3-04

Sampling Period

0

500

1,000

1,500

2,000

2,500

3,000

BTEX

MTBE

PA BEDROCK SITE - IW5

OXYGEN INFUSION PHASE

MTBE & BTEX TRENDS, AVERAGE FOR QUARTER

29

PA BEDROCK SITE - IW6

OXYGEN INFUSION PHASE

MTBE & BTEX TRENDS, AVERAGE FOR QUARTER

0

50

100

150

200

250

300

Q1-03 Q2-03 Q3-03 Q4-03 Q1-04 Q2-04 Q3-04

Sampling Period

0

50

100

150

200

250

300

350

BTEX

MTBE

30

Pump and treat system was highly successful in establishing hydraulic control and in treating off site contamination where hydraulic conductivity is high.

On site contamination where hydraulic conductivity is low and initial groundwater contamination was highest have been markedly reduced by iSOC installation. Prior to effective use of oxygen infusion, groundwater contamination on site remained high despite 3 years of pump and treat.

On site oxygen infusion substantially reduced contamination by increasing DO levels and by creating multiple pathways for oxygen diffusion.

31

Free phase petroleum was discovered April 2003 in two of six newly installed infusion wells. Some source contamination evidently is entrapped within fractures of bedrock intersected by the wells.

Recalcitrant areas of on site groundwater contamination appear to result in areas where there is a good hydraulic connection to source areas.