1

Hydraulic dredge

Pipeline to geotubes

Photo from: Little Lake Cleanup Team

2

Sediment processing facility

Water treatment plant

Geotubes (separates dredge water from mud)

Truck disposal route

From: Little Lake Cleanup Team

3

• Water drains by gravity

• Less labor/equipment

• “Decouples” dredging & dewatering

• Less potential air release

Separating dredge water using “geotubes”

Extra slide

4

Dewatering - geotextile tubes

GravelWater collection pipe

Liners

TubesBerm

From: Little Lake Cleanup Team

Extra slide

5From: Little Lake Cleanup Team

Filling geotubes

Extra slide

6

Solids captured & water drains out

Extra slide

7

Stacked geotubes

Geotubes need a lot of space

8From: WDNR webpage

Water treatment

• Air flotation• Sand/gravel filters• Carbon filters

9

Landfill disposal*

Loading

* Engineered for contaminant containment

10

1. Commitment to goals

2. Flexibility

3. Cooperation

4. Coordination & communication

Good effort

11

Why are we doing all this anyway?(time to fish recovery)

51

29

<1 <1 <1 <1

0

10

20

30

40

50

60

Cleanup LevelsNo Action 5 ppm 1 ppm 0.5 ppm 0.25 ppm 0.125 ppm

<

Yea

rs

12

Project Objectives

• Clean water

• Edible fish

• Ecological improvements

13

Lake Winnebago

From: DEA, 2003

Capping: possible dredging supplement

1. Post-capping water depth 3-feet+

2. Not in navigation channel

3. Avoid pipelines, utilities, etc.

4. PCBs less than 50 ppm

Possible capping

Sand cap

Sediment

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1. Stirring up (resuspension)

2. Leftover contamination (“residuals”)

3. Habitat effects

4. Disposal

DredgingIssues

15

16

Dredging critics*Resuspension

Extra slide*Not U.S. EPA view

*

17

Contaminant losses during dredgingHudson River White Paper Resuspension of PCBs During Dredging

• 5 Projects

• 388 observations

Average loss: mechanical dredge 0.3%

Average loss: hydraulic dredge 0.1%

18

DredgingSurface water monitoring

Wat

er c

lari

ty(t

urb

idity

)

Background levels

dredging

dredging

dredging

dredging

dredging

10/24

/05

10/23

/05

10/25

/05

10/26

/05

10/27

/05

10/28

/05

dredging

DaysFrom: OU 1 Environmental Data Memorandum, November 2, 2004

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Contamination left behind(dredging “failures”)

Critics view: “…no contaminant concentration reduction.”

Reasons:

1. Shallow bedrock

2. Debris (e.g., rock and wood)

20

Shallow bedrock: “leftovers” are hard to remove

River

Residual sediment

Bedrock

21

Wood debrisManistique River, MI

22

Rock debrisGrasse River, NY

23

Concentrations after dredging

94AVERAGE99PCBsLake Jarnsjon, Sweden92CadmiumMarathon Battery, NY97PCBsNew Bedford, MA97PCBsCumberland Bay, NY99PCBsGM Massena, NY79PCBsGrasse River, NY

Average % ReductionContaminantProject

From: Hudson River Responsiveness Summary White Paper (312663),Post-Dredging PCB Residuals

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05

101520253035404550

Fox River dredging projectConcentration reduction

Average PCB concentrations (ppm)

Pre-dredging Post-dredging

96% reduction*

50

2

*For all sediments

25

March 1999 (after excavation)

Habitat disruption - Bryant Mill Pond

26

August 1999 (4-months after excavation)

Habitat recoveryBryant Mill Pond

U.S. EPA and WDNR, 2002, Record of Decision, Operable Unit 1 and Operable Unit 2, Lower Fox River and Green Bay, White Paper 8 – Habitat and Ecological Considerations as a Remedy Component for the Lower Fox River

27Groundwater

Liner system

Capping system

Native clay soil

Disposal: engineered landfill

Waste

28

Treatment - sediment melting (vitrification)

29

Melting versus landfill disposal(Fox River upstream)

$21 million$48 millionCosts (upstream project)

Proven effective

Successful small scale test

Technology development

No (landfill space used)

Yes (beneficial re-use)

Treatment

Landfill disposal

Melting(i.e., vitrification)

Preferred

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Capping

Sand cap

Contaminated sediment

31

Dredging versus Capping

Remains in river

Landfill

Permanent change

Altered/disrupted (eventual recovery)

Habitat

Contained*Mostly removedContaminant disposition

No releasesSmall releaseShort-term releases

CappingDredging

Preferred *Assumes long-term stability

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Dredging versus Capping

ModerateHighCost

Less noise, traffic, odors, etc.

Some noise, traffic, odors, etc.

More monitoring & institutional

controls

Limited followupmonitoring

DecreasedIncreasedWater depth

Monitoring & maintenance

Smaller “footprint”Larger “footprint”Construction impacts

CappingDredging

Preferred

33

Capping• Best in quiet waters

• Typically for low toxicity contamination

Photo courtesy of Bean Environmental, LLC.

34

Cleanup options summary

• “One size does not fit all”

• Unique site conditions should be considered

35

Economic benefits of cleanup

• Increase in property values (e.g., Waukegan Harbor: $53,000 increase per house following cleanup*)

• Cleanup-related jobs & business

• Health benefits

* Braden, J.B., et al, 2004, Contaminant Cleanup in the Waukegan Harbor Area of Concern: Homeowner Attitudes and Economic Benefits, Journal of Great Lakes Research.

36

Economic benefits of cleanup(continued)

• Recreation improvements & tourism (e.g., removal of fish advisories)

• Lower navigation dredging costs and/or increased commercial use

37

Economic benefits to communities from cleanups

$ 1 million

$ 4.2 million

$ 14 million

$ 4.6 million

$ 7 million

$ 2 million

$ 13.2 million

$ 142 million

$ 70 million

Annual income

$ 32.5 million

$ 22 million

$ 6 million

Annual income

No.No.

8001200RaymarkInd., CT ($80 million)

4300700Industri-Plex, MA ($60 million)

2500235Ft. Devens, MA

AnnualState taxes

Propertyvalue

increase

Permanent jobs

Short-term jobsSuperfund

project & cleanup costs

From: EPA, Superfund: The Road to Recovery Extra slide

38

Economic benefits to communities from cleanups

Park fees

$ 0.6 million

$ 0.1 million

$ 67 million

$ 0.03 million

$ 0.4 million

---

$ 1.9 million

$ 0.5 million

Annual income

$ 2.1 million

$ 3.7 million

$1.2 million

Annual income

No.No.

---90ChismanCreek, VA

113145Denver Radium, CO ($130 million)

2042Old Works, MT

Annual State taxes

Propertyvalue

increase

Permanent jobs

Short-term jobsSuperfund

project & cleanup costs

Extra slideFrom: EPA, Superfund: The Road to Recovery

39

Big river sites cleanups

2.7 million$ 460 millionHudson, NY

?$ 600 million (?)Housatonic, MA

1.0 million?Kalamazoo, MI

Fox River, WI 7.2 million$ 400 million

Contaminated sediment

(cubic yards) Cleanup costsSite

40Photo from Ann Schell

More information:http://www.epa.gov/region5/sites/foxriverhttp://www.dnr.state.wi.us/org/water/wm/foxriver/index.htmlhttp://www.littlelakecleanup.com/pages/1/index.htm

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