Assessment and Remediation of ChlorideImpacted Groundwater: A Case Study

Gordon MacMillan, Matrix Solutions Inc.

Robert Pockar, Matrix Solutions Inc.

Brent Bowerman, Canadian Natural Resources Ltd.

High Level

Edmonton

Calgary

Fort McMurray

Grande Prairie

GOLD CREEK

GAS PLANT

B

B

88-3

88-8

88-1

86-5-1 86-5-286-6-2

00-1800-19

86-6-1

P97-1A

00-17

88-9

88-2B88-2A

88-7

FORMERAMINE POND

FORMEREVAPORATION

PONDFORMER

BURNPIT

SCALE

0 50 m

WETLAND

ACC ESS

ROAD

LEGEND

GROUNDWATER CONTOUR

GROUNDWATER ELEVATION

MONITORING WELL LOCATION

GROUNDWATER FLOW MAP

BUSH

BUSH

BUSHBUSH

BUSH

88-3

88-8

88-1

86-5-1 86-5-286-6-2

00-18

00-19

86-6-1

P97-1A00-17

88-9

88-2B88-2A

100

0

3000

1 0000

3000

0

88-7

FORMERAMINE POND

FORMEREVAPORATION

PONDFORMER

BURNPIT

SCALE

0 50 m

WETLAND

ACCESS ROAD

ACC ESS

ROAD

LEGEND

MONITORING WELL LOCATION

CHLORIDE CONCENTRATION (mg/L)

A'

A

4,140

6,120

34,100

19,400

1,110

64.4

9,650

11,500

722

6,590

1,760

12,400

30,300

486

5,210

4,140

AREAL CHLORIDE DISTRIBUTION

B

88-7

B

88-3

88-8

88-1

86-5-1 86-5-286-6-2

00-1800-19

WETLAND

86-6-1

P97-1A

00-17

88-9

88-2B88-2A

SCALE

0 50 m

FORMERAMINE POND

FORMEREVAPORATION

PONDFORMER

BURNPIT

LEGEND

MONITORING WELL LOCATION

APPARENT CONDUCTIVITY (mS/m)

50 80 110 140 170 200

ACCESS

ROAD

VERTICAL CONDUCTIVITY

VC23VC24

VC25 VC26

VC22

VC21

VC20

VC1VC2 VC3

VC4

VC5

VC6VC7

VC8

VC19 VC18 VC17 VC16 VC15 VC14 VC13 VC12 VC11VC10

VC9

EM31 APPARENT CONDUCTIVITY DATA VERTICAL DIPOLE

200

200400

400600

600

800

800

1000

600

200

200

200

4,120

30,300

12,400

6,590

97-7A

86-5-2

FORMER PIT AND POND AREA

88-2B

88-897-1A

00-18WETLAND

SOUTHA

NORTHA'

SILTY CLAY FILL

TOPSOIL

SAND

SAND

CLAY TILL

SI LTY SA ND

SAND / SANDY SILT?

?

?

98

97

96

95

94

93

92

91

90

89

88

DEP

TH (m

)

HORIZONTAL SCALE

0 100 m

6,590

WATER LEVEL ELEVATION

SCREEN INTERVAL

TOTAL DEPTH DRILLED

CONDUCTIVITY CONTOUR

CHLORIDE CONCENTRATION (mg/L)

1000

34,400

VC25

VC4

VC14

VERTICAL CHLORIDE DISTRIBUTION MAP

Remediation Objective

Protect wetland from further impact by:

1) Capturing chloride impacted groundwater andprevent elevated chloride from discharging to the wetland.

2) Removing dissolved chloride from the subsurface

BUSH

BUSH

BUSHBUSH

BUSH

88-3

88-8

88-1

86-5-1 86-5-286-6-2

00-18

00-19

86-6-1

P97-1A00-17

88-9

88-2B88-2A

100

0

3000

1 0000

3000

0

88-7

FORMERAMINE POND

FORMEREVAPORATION

PONDFORMER

BURNPIT

SCALE

0 50 m

WETLAND

ACCESS ROAD

ACC ESS

ROAD

LEGEND

MONITORING WELL LOCATION

CHLORIDE CONCENTRATION (mg/L)

4,140

6,120

34,100

19,400

1,110

64.4

9,650

11,500

722

6,590

1,760

12,400

30,300

486

5,210

4,140

GROUNDWATER REMEDIATION SYSTEM

B

B

88-3

88-8

88-1

86-5-1 86-5-286-6-2

00-1800-19

86-6-1

P97-1A

00-17

88-9

88-2B88-2A

92

93

94

95

88-7

FORMERAMINE POND

FORMEREVAPORATION

PONDFORMER

BURNPIT

SCALE

0 50 m

WETLAND

ACC ESS

ROAD

LEGEND

MONITORING WELL LOCATION

SIMULATED HYDRAULICHEAD CONTOUR (m)

CAPTURE ZONE

CAPTURE ZONE

PREDICTED HYDRAULIC HEAD DISTRIBUTION AFTER SIX MONTHS

0 4 8 12 16 20 240

2

4

6

8

10

12

Duration of Pumping (Months)

it

(

GROUNDWATER INTERCEPTION TRENCHPredicted Groundwater Production Rate

PREDICTED GROUNDWATER RECOVERY RATE

Pre

dict

ed G

roun

dwat

er R

ecov

ery

Rat

e (m

3 /da

y)

NTS V

ALV

E TRE

E

RW2 V

ALV

E TRE

E

RW4 V

ALV

E TRE

E

RW1 V

ALV

E TRE

E

V-170

M

RW1 RW2 RW4RW3

RW3 V

ALV

E TRE

E

P-150

VALVE TREE SCHEMATIC

R-160

LEGEND

V-140

F-130

P-1

00

P-1

00

P-1

00

P-1

00

P-1

00

2"-PVC-80°

1"- P

VC- 8

0°

1"- P

VC- 8

0°

1"- P

V C- 8

0°

1"- P

VC- 8

0°

1"- P

VC- 8

0°

1"- P

E-160

PSI

1"- P

E-160

PSI

1"- P

E-160

PSI

1"- P

E-160

PSI

1"- P

E-160

PSI

2"-PE-100 PSI

2" - CAR

BON ST

EEL

1/2" -SS

1 /2" - S

S

1/2" -SS

1"- P

VC- 8

0°

LOCATED WITHING THEMETERING BUILDING

M M M M

M

PI

PI

PI

CR

FQI

PI

PI

INSULATED AND HEAT TRACED

BALL VALVE

CHECK VALVE

BUTTERFLY VALVE

PRESSURE INDICATOR

UNION

INSTRUMENT ELECTRICAL LINE

HIGH HIGH LEVEL SWITCH

GATE VALVE

REDUCER

TEE

1/2"-NPT THREAD

NEEDLE VALVE

THREE WAY VALVE

FILTER

5

5

GROUNDWATER RECOVERY SYSTEM PROCESS AND INSTRUMENTATION DESIGN

Remediation System Performance

Cumulative Chloride Recovery

0

500

1,000

1,500

2,000

2,500

20-Jul3-A

ug17-A

ug31-A

ug

Date

Rec

over

ed C

l Mas

s (K

g)� System has been in operation

since July 2002.

� Initial groundwater recoveryrate of approximately 5m3/day.

� Recovered groundwater hasan average concentration of9,000 mg/L.

� Average chloride recoveryrate of 50 Kg/day.

� Future work includesestablishing site specificremediation criteria.

Assessment and Remediation Review

� Clearly identify the purpose of the project:� Fresh groundwater

� Aspen stand

� Detailed assessment proved invaluable throughout eachstage of the project:

� Explore possibility of natural attenuation

� Trench and well depth and locations

� Recovery rates

� Simple numerical simulation is a valuable tool for:� Evaluation of the remediation system

� Estimate of capture zones

� Estimation of recovery rates for pump and line sizing