Session 9 Linking the CSM to Remedial -...

November 7, 2013

Beyond Data Session 7 Remedial

Approaches 1

1

Session 9

Linking the CSM to Remedial

Approaches and Applications

2

Recognize that a wide variety of

remedial options exists

Know the four main types of

remedial options

Understand the link between a CSM

and remediation

Learning Objectives

3

Remediation of

Contaminated Sites

Yesterday's innovations – where are

they now?

What is innovative today? Where are we

going?

Example case studies – tried and true

vs. new approaches

November 7, 2013


Approaches 2

4

Some Lessons Learned

Source Removal can be achieved by

Excavation

Soil Vapour Extraction (SVE), BUT

Have a good conceptual site model (CSM) that is robust and

science-based !

e.g., clays can be fractured; fractures can carry NAPL

SVE does not work below the water table

Groundwater chemistry is a critical component of the CSM

Improved parameters for petroleum hydrocarbons

Major ion chemistry and indicator parameters

5

Key Elements of a Conceptual Site Model

Site History and Setting Historic and current operations and

practices

Potential Areas of Environmental

Concern

Potential Contaminants of Concern

Geology and Stratigraphy Regional and local

Overburden – sedimentary;

glaciology, depositional processes

Bedrock – lithologies, facies, fracture

networks, representative elementary

volume

Hydrogeology Aquifers and aquitards

Groundwater levels and elevations

Hydraulic gradients and velocities

Hydrogeologic boundaries

Contaminant Extent,

Plumes and Pathways Soil, Groundwater and Soil Vapour

Transport and Attenuation

Processes

Heterogeneity, Anisotropy and Scale

Receptors and Risk Terrestrial, aquatic, human

Routes of exposure

Toxicity and Dose

6

Brainstorming exercise

Consider the Strawberry Hill site

Focus just on the dry cleaner (DNAPL) issue

Brainstorm possible remedial approaches for two

future use options

(see next slide)

Large Group Exercise

Large group discussion.

November 7, 2013


Approaches 3

7

Option A

Redevelopment of entire Strawberry

Hill mall

Condos and two levels of

underground parking over the

property footprint

Option B

Continue with the present site uses

Strawberry Hill Redevelopment

Options

Large group discussion.

8

Large Group Discussion

Remember!

When

brainstorming, allideas are good

ideas!

9

Any other ideas?

Large Group Debriefing

Debrief large group Discussion.

November 7, 2013


Approaches 4

10

Question:

What did you realize as we brainstormed

remedial options?

Answer:

Having a robust Conceptual Site

Model is critical!

Without this, you do not know

what remedial designs might work

Large Group Debriefing

Debrief large group discussion.

11

Contaminant Zones

Reference: EPA, 1992

12

Typical Remediation

Options

Manage Risks Monitor

Environmental and/or Human Health Risk Assessment

Source Removal Excavation or Dredging (off-site or on-site disposal; on-site treatment)

In situ treatment (e.g., Soil Vapour Extraction; Biodegradation; Chemical Oxidation, Thermal, etc.)

Source and/or Plume Control Hydraulic Methods (e.g., pump-and-treat)

Physical Control (e.g., sheet pile cut-off walls)

Biological Control

Permeable Treatment Walls

Combinations

November 7, 2013


Approaches 5

13

350 Ellis Street, Mountain

View California

Circa 1987

14

MEW Superfund Site

15

1000 ug/L

100 ug/L

10 ug/L

TCE Soil Vapour Survey - 350 Ellis Street

November 7, 2013


Approaches 6

16

Stratigraphic Cross Section

17

The Solution –

Risk Management

• 100-ft deep soil

bentonite cut-off wall

• Pump-and-treat

• SVE

18

Source Control – Hydraulic Containment

Examples of

hydraulic

containment

in plan and

cross section

Pumping well

Drain

Well within a barrier wall system

November 7, 2013


Approaches 7

19

19Törökszentmiklós

Groundwater Treatment Plant

TOR-1

20

Water Treatment System

October 2006: P&T system reinstalled, SVE systems

extended, in-well stripping pilot test

Source: Ecosurvey, 2007

21

350 Ellis Street Site Today

November 7, 2013


Approaches 8

22

And what was happening in

Vancouver??

The need for comprehensive contaminated sites legislation was

recognized soon after “EXPO ‘86” in Vancouver, once the Province

assumed responsibility and liability for the investigation and cleanup of

the Site...

Ca. 1990 Oct 2012

23

Pacific Place Site A Risk Managed Solution:

Soil Excavation

Hydraulic Controls – pump& treat

Barrier Wall

24

Thunder Bay, Ontario

Wood Preserving Site

xxxxxxxxxxxxxxxx

Area ≈136,400 m2

(34 acres)

November 7, 2013


Approaches 9

25

Installing Waterloo Barrier

Waterloo Barrier Wall installation through sand fill adjacent to rock fill containment berm.

26

Waterloo Barrier – Thunder

Bay ON

27

November 7, 2013


Approaches 10

2828

Workshop Takenaka: CSM Test in May 2004

29

Cutter Soil Mixing Test - Japan

Top of CSM

wall

In-situ clay

30

North America’s First CSM Project

Vancouver Island

Convention Centre

November 7, 2013


Approaches 11

3131

North America’s First CSM Project

32

Vancouver Island

Convention Centre

33

Source Control Permeable Treatment Walls

Source: Department of Earth Sciences, University of Waterloo

http://www.science.uwaterloo.ca/research/ggr/PRBPlumeDiagram.gif

http://www.science.uwaterloo.ca/research/ggr/PRBPlumeDiagram.gif

November 7, 2013


Approaches 12

34

34

35

Sulphate Reduction Wall,

Sudbury, Ontario

Treating Inorganics in Groundwater

• Small-scale studies have demonstrated

treatment of Cd, Cr, Cu, Fe, Ni, Pb, NO3, PO4, SO4

36

PEC Site, Vancouver

November 7, 2013


Approaches 13

37

Zero-Valent Iron Filings Wall,

Denver CO.

38

Groundwater flow

Borehole location

SCHEMATIC FUNNEL AND GATE

Collector

Pit

Distributor

Pit

Slurry

Wall

Vent

Monitoring

Points

Groundwater

Flow

Fe

Filings

Reactor

Vessel

Impermeable

Slurry Walls

Reactive

“Gate”

Pit

Distributor

Pit

FUNNEL AND GATE CONSTRUCTION)

39

Permeable Reactive Iron Gate

Monkstown,

Northern Ireland

November 7, 2013


Approaches 14

40

41

Total PAH Concentrations in Sediment (0m to greater than 8m Below River Bed)

42

Caisson Dredging

November 7, 2013


Approaches 15

43

Meadow Avenue Remedial Works

Old Wharf

New Wharf

Engineered Cover

REF: APEGBC

Innovation Magazine

44

Source Removal: LNAPL Recovery

LNAPL

extraction

well

45

Source Removal

Why Excavation?

Excavation remains a common remedial strategy

Often preferred where:

Relatively small volumes

Non-hazardous material

Accessible without impractical level of effort

November 7, 2013


Approaches 16

46

Why Excavation?

But also selected because:

Landfill disposal costs remain relatively low

The technology requires a relatively short time frame

There is certainty in the outcome

Uncertainties in the investigation are revealed

47

Hydrostatic case –LNAPL is like an iceberg

LNAPL Can Exist Below Water Table

This leaking diesel tank site was excavated

three times!!

48

November 7, 2013


Approaches 17

49

Operator’s Perspective

50

Soil Treatment Options

Landfills (on-site, off-site)

Confined Disposal Facility, ``CDF`` (e.g. ,

Hamilton Harbour)

Biological Treatment (e.g., biopiles)

Stabilization

Others

51

Sydney Tar Ponds – After

Remediation

November 7, 2013


Approaches 18

52

Source Removal - In situ Treatment

Treats source zone in place (in situ)

No soil removal

Reduces mobility, toxicity or concentration of

contaminants

Often considered where simple excavation is

costly

e.g., demolition otherwise required to remove soil under

buildings or other large structures

53

Biodegradation of Hydrocarbon

Plume

54

In-situ Bio-Treatment

Typically uses native bacteria to biodegrade susceptible organics

Additives (nutrients, oxygen, bacteria) may be injected to enhance

the process

New developments with enzyme additives

November 7, 2013


Approaches 19

55

In-situ Treatment

Soil Vapour Extraction (SVE)

Withdrawal of soil vapours by vacuum pumps

Use drilled wells or trenches

Only useful for volatile compounds chlorinated solvents,

petroleum products

55

56

IN SITU AIR SPARGING (IAS)

Typical IAS/SVE

compressor blower

57

Skagway, Alaska USA

Full-Scale IAS/SVE System

Blower

Sparge wells

SVE Well

November 7, 2013


Approaches 20

58

Vacuum Enhanced Recovery (VER)

Also Known As: High-Vac Extraction

Bio-Slurping

Withdrawal of soil vapours, LNAPL product, and groundwater by vacuum pumps

Useful for volatile and semi-volatile compounds solvents, petrol, diesel, jet fuels

59

VER System – rail yard

500, 000 L diesel fuel

plume

20 m below grade

Selected Remedial

Technology conventional pumping system

and VER system

Currently in operation

60

In Situ Physical/Chemical Treatment

Injection of chemical

oxidants, surfactants, or

alcohols into source

zone Using drilled wells or

trenches

Usually works quickly, but

rarely removes 100% of

problem

Requires full contact

between injected chemicals

and contaminants

http://www.rustsolver.com/products/pp_1lb.jpg

http://www.rustsolver.com/products/pp_1lb.jpg

November 7, 2013


Approaches 21

61

Hydrogen Peroxide – Fentons’ Reaction

62

63

Potassium Permanganate

November 7, 2013


Approaches 22

64

65

In Situ Injection Micro-

Scale Iron

~50 nm

e-

C2HCl3 C2H6 + 3Cl-

Fe2+

5[H]

Pd0

Fe0

Bimetallic Nano-scale Particles

66

ZVI

66

• Injection requires stabilizers to

prevent agglomeration (e.g. soya milk)

November 7, 2013


Approaches 23

67

PRB with Zero Valent Iron – Alabama, 2010

68

In Situ Soil Mixing with ZVI

- 2012

PCE dry cleaning site

northern Alberta

69

Where are we going?

Michael Borda’s Top Five

1. Electro kinetic enhanced bioremediation (EK-Bio) - this is being

done by several groups in the US.

2. In Situ Thermal - not new, but can be applied to systems where matrix

diffusion is the issue, and therefore will be important in the future.

3. mZVI plus Bioremediation - work like we are doing using ZVI as an

enhanced bioremediation strategy.

4. Surfactant-Enhanced iSCO - There is a place for this type of

approach – but lots of hype (VeruSOL® by VeruTEK).

5. Bioremediation Using Enzymes - great potential for site-specific bio

solutions with custom enzymes (e.g., really cool stuff for PCBs)

November 7, 2013


Approaches 24

70

71

http://www.hollandenvironment.com

/project-services.html

72

In Situ Thermal Treatment

In situ heating of soil using buried electrodes or steam injection

Vapors are extracted and treated

Contaminants are removed from sands, silts and clays

Examples:

Six-phase electrical heating

In situ destruction (e.g., Terra-Therm)

Heating elements

http://www.hollandenvironment.com/

November 7, 2013


Approaches 25

73

In Situ Thermal - Soil Heating

x-Distance (m)

Ele

v.(m

)

0 5 10 15 200

2

4

6

8Section B-B'

degC

y-Distance (m)

Ele

v.(m

)

0 5 10 15 200

2

4

6

8

Section A-A'

X (m)

Y(m

)

0 5 10 15 200

5

10

15

20

185

160

135

110

85

60

35

10

Temperature (degC)

130 days

B B'

A

A'

CompFlow Simulation,Extraction à Chaleur, 130 jours

Extraction with heating, 130 days

x-Distance (m)

Ele

v.(m

)

0 5 10 15 200

2

4

6

8Section B-B'

degC

y-Distance (m)

Ele

v.(m

)

0 5 10 15 200

2

4

6

8

Section A-A'

X (m)

Y(m

)

0 5 10 15 200

5

10

15

20

185

160

135

110

85

60

35

10

Temperature (degC)

130 days

B B'

A

A'

CompFlow Simulation,Extraction à Chaleur, 130 jours

Extraction with heating, 130 days

Six-Phase

Electrical Heating

CompFlow Simulation

130 days

75

A New Term – “Transition Sites”

"The complete removal of contaminants from groundwater at possibly thousands

of complex sites is unlikely, and no technology innovations appear in the near

time horizon that could overcome the challenges of restoring volatile organic

compounds to drinking water standards.

"At many of these complex sites, a point of diminishing returns will often occur

as contaminants in groundwater remain stalled at levels above drinking water

standards despite continued active remedial efforts.

We are recommending a formal evaluation be made at the appropriate time in

the life cycle of a site to decide whether to transition the sites to active or

passive long-term management.“

REF: National Academy of Sciences (2012, November 8). Clean-up of some U.S. contaminated

groundwater sites unlikely for MLA decades. ScienceDaily. Retrieved January 12, 2013, from

http://www.sciencedaily.com /releases/2012/11/121108131818.htm

76

Technical Challenges

Consultants simplify to understand reality and seek

solutions A Conceptual Site Model is a good tool but is a simplification of reality

Nature is not always simple Heterogeneity is the rule – not the exception

Innovative approaches may manage rather than

remove the problem Many contaminated sites will require monitoring for many, many years

November 7, 2013


Approaches 26

77

End of Session 9

Linking the CSM to Remedial

Approaches and Applications

78

Your major insights from the course?

Did the course meet your expectations?

What will you put into practice?

How will you share what you have

learned with others?

Course evaluations

Course Wrap-Up

Session 9 Linking the CSM to Remedial -...

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