Mixing Below Mudline

Sediment Remediation/Risk Management by In Situ Stabilization/Treatment (ISS/T) with Deep Soil Mixing (DSM)

© Canada Geo-Solutions 2017

Pete Craig, M.Sc., PChem (BC)Regional ManagerCanada Geo-Solutionsrpcraig@geo-solutions.com250.885.7940

• Introduction• Sediment Contamination & Remediation• Sediment Amendment (“In Situ Treatment”) • Drops and Rakes and Chisel Plows• Underwater Soil Mixing, ISS & IST• Case Study – Sediment Stabilization for Wharf

Construction• Case Study – Connecticut River• Case Study – Marine Turning Basin• Conclusions• Contacts• References/Further Reading

• Canada Geo-Solutions, Inc. (Vancouver, 2008)• Parent company: Geo-Solutions Inc. (founded 1996)

• Oldest soil mixing contractor in North America• Largest installer of ISS/T• Acquired largest competitor 2012 (Geo-Con/Environmental Barriers, founded 1979)

• $50 to $70 M/year worldwide• Bonding to $75M+ (aggregate)

> 1500 total projects> 800 slurry trenches> 5M m2 cut-off wall> 1M m3 soil mixing

1st use of soil mixing for environmental

remediation

1st use of soil mixing for environmental

remediation

1st containment slurry wall

1st containment slurry wall

1st containment slurry wall

1st containment slurry wall

1st reactive barrier and 1st zero valent iron treatment site

1st reactive barrier and 1st zero valent iron treatment site

1st deep containment wall using soil bentonite slurry wall method for

oil sands tailings containment

1st deep containment wall using soil bentonite slurry wall method for

oil sands tailings containment

1st to complete several projects using slurry wall, soil mixing and

biopolymer technology

1st to complete several projects using slurry wall, soil mixing and

biopolymer technology

International Firsts

Low permeability barriers to great depths (29 m w/ excavator, >29 m w/ clamshell) 

Mixing of reagents in situ to remediate contaminated soil/sediment or stabilize/improve subgrade

High‐pressure grout jetting, physically mixing underground columns, often within tight quarters and around obstructions

Deep drains and interceptor trenches

Passive underground reactive filters to treat contaminated groundwater

Barrier WallsBarrier Walls Soil MixingSoil Mixing Jet GroutingJet Grouting Vertical DrainsVertical Drains Permeable Reactive Barriers

Permeable Reactive Barriers

Adapted from Washington Department of Ecology, 2016 (Lower Duamish Waterway Source Control Strategy)

Air DepositionWaterway

Operations & Spills

Resuspension & Redeposition

Erosion & Leaching

StormwaterRunoff & Nonpoint Sources

Overwater Operations

Storm Drains, Combined Sewers and

Cross-Connects

Upland Contaminant

PlumesSediment from

Upstream

Pre-2000

Removal

Cap

Monitored NaturalRecovery/Attenuation

Hybrid Remedy

Post-2000

n = 47 n = 39

4

34

72

1

2015

3

Source: Anchor QEA [Mohan, R., Doody, J.P., Patmont, C., Gardner, R., Shellenberger, A. (2016).

8

EPA• 2005 USEPA ‐ Contaminated Sediment Remediation Guidance

NRC• 2007 National Research Council – Sediment Dredging – Assessing the Effectiveness

USACE• 2008 (February) US Army Corps – The “Four R’s”• 2008 (September) US Army Corps – Technical Guidelines for Environmental Dredging

EPA• 2013 USEPA ‐ Use of Amendments for In Situ Remediation at Superfund Sediment Sites, 

(OSWER Directive 9200.2‐128FS)

ITRC• 2014  ITRC ‐ Remedy Selection for Contaminated Sediments

USEPA: OSWER Directive 9200.2-128FS (2013)

10

Golder Associates (2009): “Limnofix In Situ Treatment Technology”

USEPA: OSWER Directive 9200.2-128FS (2013)

Ghosh, U., Luthy, R.G., Cornelissen, G., Werner, D. and Menzie, C.A., 2011. In-situ sorbent amendments: a new direction in contaminated sediment management. Environmental Science and Technology (45) 1163-1168.

>10x reduction in

uptake

United States Europe

Graphic: Anchor QEA [Mohan, R., Doody, J.P., Patmont, C., Gardner, R., Shellenberger, A. (2016)]

“These projects have demonstrated the efficacy of full‐scale in situ sedimentimmobilization treatment technologies to reduce the bioavailability and mobility of a range of organic and metal contaminants, including PCBs, PAHs, dimethyl dioxane, dioxins/furans, chlorinated benzenes, tributyltin (TBT), and mercury” 

‐ ITRC (2014)

Photos: Luthy (2009)

Solidification – bind target in a solid block of low permeability material Stabilisation – transform contaminants and reduce leachability.

“Wisconsin Department of Natural Resources (WDNR) determined that the in situ solidification process did little to treat the sediments. Therefore, no 

further treatments were conducted.”Renhold (1998)

• Reagents are injected and mixed with the soil

• Processes vary:• Dry vs. wet• Auger vs. bucket vs. rotary tool

• Single auger vs. multi auger• Single stage vs. multi stage

• Related/Similar: Jet Grouting

clu‐in.org (above); geo‐solutions (below)

Soil Mixing

o Potentially cost-effective alternative to tradition sediment remedieso Selected in Gowanus Canal ROD*o Same mixing equipment routinely used in uplands for ISS & IST

o Advantages◦ Performed in situ – no removal, drying (bulking) or disposal of sediment. ◦ No open cut, no sideslope failures. ◦ Deeper (below mudline) applications than traditional technologies ◦ Dependent on allowable volumetric expansion, can be single step process◦ May or may not require capping dependent on requirements of waterway

(can be used to support caps)◦ Reduces scour and erosion of sediment, banks and channels

*U.S. Environmental Protection Agency (2013). Record of Decision: Gowanus Canal Superfund Site Brooklyn, Kings County, New York. USEPA Region II. New York, New York. USEPA Document 692106.

Kitazume & Terashi (2013)

“The strength gained during the solidification process, as shown in this study, would minimize any potential for erosion or migration of the sediments subjected to rapid river flow or estuarine dynamics during storm events. Therefore, it is possible that this technique could be used as an effective interim remedial measure to stabilize highly contaminated sediments while managers determine the appropriate course of action (removal or capping). This approach provides unprecedented flexibilityby reducing risk of loss while still allowing for the full range of possible final remedies up to and including removal, decontamination and beneficial use.” 

- Maher , W. S., et al. (2007). Cement Deep Soil Mixing (CDSM) for Solidification of Soft Estuarine Sediments. Marine Georesources & Geotechnology. 25:3-4, 221-235, DOI: 10.1080/10641190701699319 re: FHWA-NJ-2005-028

Former Boat Slip New Bedford, Massachusetts

Stabilization of coal tar impacted harbor sediments.Prior to stabilization, the sediments were dredged from a nearby harbor and placed in a sheet pile enclosure.GSI performed auger mixing from a work platform constructed of cement mixed soil spoils and crane mats to work its way into and across the weak sediments.Performed a design mix ahead of field construction.

Owner: New England UtilityConstruction Dates: August – September 2011Scope: ISS of MGP impacted dredge sediments

~5,400 m3 (7,000 CY) stabilized using large diameter soil mixing up to 9 m (30’) BGS

Goals: UCS > 345 kPa (> 50 psi), Permeability < 1x10-6 cm/s, Leachability reductionSpecial Notes:

– All work completed using an excavator mounted drill rig fitted with an 2.4 m (8’) auger from atop timber crane mats to avoid sinking in the unconsolidated, high moisture content, dredge sediments

– Stabilization mix consisted of Portland cement added to the soils by wet weight at 17%.

MGP Contaminated Sediment 4.9 to 5.5 m (16’ to 18’) water depth from top of barge to river bottomSolidification Depths from 0 to 5.2 m (0’ to 17’) below sediment surfaceRiver flows of 170 to 425 m3/sec (6,000 to 15,000 CFS)Alluvial Deposits of narrowly graded sands and silt with trace sub angular gravel deposits80’ x 120’ Flexi Float Barge system with 30’ x 30’ working pool

◦ Mobilize  and set up ISS equipment on Flexi‐Float Barge system including: Batch Plant (cement silo, pumps, high shear mixer)80 tonne (180,000 lb) Hydraulic Drill Rig

◦ Relocate barge to drilling site 8 km (5 miles) down river◦ Install 12 to 15 ISS Columns to varying depths Vary operational parameters including RPM, penetration, grout flows and mixing passes

◦ Vary mix designs and reagent additives

1.4 m (4.5’) Diameter AugerTest Column Layout included typical column spacing to achieve 100% coverage13 Columns in total were completed to various depths between 2.4 to 5.2 m (8’ to 17’) below sediment surface

Measured pH and Turbidity, at the Monitoring PointsVisual inspections for sheen and turbidity within working pool, inner and outer silt curtains Swell MeasurementsISS rig monitoring - Grout Flow, Depth, Rotations Per Minute (RPM), Strokes, Rotary Head Pressure

Parameters at the Monitoring Point did not exceed background conditions measured at the Reference Point.

Sheen observed was confined within the established limits of the dual turbidity curtains/absorbent booms.

Swell was recorded at approximately 0.15 to 0.3 m (0.5’ to 1.0’) based on preliminary soundings.

Penetration and withdrawal speeds were slowed to further limit turbidity and disruption of the top sediment which seemingly lowered the turbidity levels.

In Situ Solidification (ISS) of 1,415 m3 (1,850 CY) sediments in a marine environment w/ vessel trafficDebris sweep with Caterpillar 324 excavator (24 ton)Same modular barge & soil mix unit drill as for riverine project1.5 to 2.4 m (5’ to 8’) thick monolith to support a reactive cap systemProcess control and local barge-mounted turbidity curtains were sufficient to control sheens, NAPL, and turbidityBulkhead stability was monitoring continuously utilizing multiple inclinometer stations, and GPS targets. No issues.

226 ISS columns over 18 days of soil mixingSediment Surface was 5.5 to 6.7 m (18’ to 22’) below waterlineNine (9) different mixes tested. Both 1.8 m (6’ ) and 2.4 m (8’) diameter augers used successfully

Sources: ITRC (2011)[6]; Gardner, F.G., et. al., (1998)[8]; Irene M.C., (1996)[9]; USEPA (2009)[10]; U.S Department of Defense (2000)[11]; U.KEnvironmental Agency (2004)[12]; Raj, D.S.S; Rekha, C.A.P, Bindhu, V.H; Anjaneyulu, Y., (2005)[13]; Conner, (1990) [14].

Performance standards met or exceededCompleted safely Demonstrated “proof of concept”Preliminary monitoring and observations indicate minimal impact to the environment and local communityViable option for full scale application in appropriate conditions

Electric Power Research Institute (EPRI). (2014) In-Situ Solidification of Contaminated Sediments: A Technology Demonstration Project. EPRI, Palo Alto, CA: 2014. 3002005216 http://www.epri.com/abstracts/Pages/ProductAbstract.aspx?ProductId=000000003002005216

http://www.geo-solutions.com/technical-papers

Technical Papers, Case Studies, Specifications:

Contact Us:

Darin R. Payne, B.Sc.Technical Director, Sediment Solutions & U.S. Regional Manager –Geo-Solutions Inc.dpayne@geo-solutions.com 727.385.9552

Pete Craig, M.Sc., PChemWestern Canada Regional Managerrpcraig@geo-solutions.com250.885.7940

Andromalos, K.B., et al. (2012). “In Situ Remediation and Stabilization of Contaminated Soils and Groundwater Using Soil Mixing Techniques with Various Reagents,” SEFE7: 7th Seminar on Special Foundations Engineering and Geotechnics. San Paulo, Brazil, June 17 to 20. http://www.geo-solutions.com/pdf/3_Soil_Mixing_with_Various_Reagents.pdf

Electric Power Research Institute (EPRI). (2014) In-Situ Solidification of Contaminated Sediments: A Technology Demonstration Project. EPRI, Palo Alto, CA: 2014. 3002005216 http://www.epri.com/abstracts/Pages/ProductAbstract.aspx?ProductId=000000003002005216

Ghosh, U., Luthy, R.G., Cornelissen, G., Werner, D. and Menzie, C.A., 2011. In-situ sorbent amendments: a new direction in contaminated sediment management. Environmental Science and Technology (45) 1163-1168.

Hills, C. and Bates, E. (2015). Stabilization and Solidification of Contaminated Soil and Waste: A Manual of Practice. Hygge Media. ISBN-13: 978-0993272943. https://clu-in.org/download/techfocus/stabilization/S-S-Manual-of-Practice.pdf

ITRC (Interstate Technology & Regulatory Council). 2014. Contaminated Sediments Remediation: Remedy Selection for Contaminated Sediments (CS-2). Washington, D.C.: Interstate Technology & Regulatory Council, Contaminated Sediments Team. http://www.itrcweb.org/ contseds_remedy-selection

James, O. and Darlington, J. (2010). “Innovative Systems for Dredging, Dewatering or for In Situ Capping of Contaminated Sediments,” Proceedings of the Annual International Conference on Soils, Sediments, Water and Energy. Vol. 11, no. 1. pp. 300–309. http://scholarworks.umass.edu/cgi/viewcontent.cgi?article=1072&context=soilsproceedings

Kitazume, M. and Terashi, M. (2013). The Deep Mixing Method. CRC Press. ISBN 9781138000056 - CAT# K16830

Lofrano, G., Libralato, G., Minetto, D. et al. (2017). In Situ Remediation of Contaminated Marine Sediment: an Overview. Environ Sci Pollut Res. 24: 5189. doi:10.1007/s11356-016-8281-x

Luthy, R. G., Cho, Y., Ghosh, U., Bridges, T.S., Kennedy, A.J. (2009). Field Testing of Activated Carbon Mixing and In situ Stabilization of PCBs. Final Report. Environmental Security Technology Certification Program (ESTCP). ER-0510. 266 pp.

Maher , W. S., et al. (2007). Cement Deep Soil Mixing (CDSM) for Solidification of Soft Estuarine Sediments. Marine Georesources & Geotechnology. 25:3-4, 221-235, DOI: 10.1080/10641190701699319

Mohan, R., Doody, J.P., Patmont, C., Gardner, R., Shellenberger, A. (2016). Review of Environmental Dredging in North America: Current Practice and Lessons Learned. Journal of Dredging (Official Journal of the Western Dredging Association). Vol. 15, No. 2: 29 -50.

Olsta, J.T. and Darlington, J.W. (2006) "Innovative Systems For Dredging, Dewatering or for In-Situ Capping Of Contaminated Sediments," Proceedings of the Annual International Conference on Soils, Sediments, Water and Energy: Vol. 11, Article 20.

Pariaa, S. and Yuet, P.K. (2006). Solidification/Stabilization of Organic and Inorganic Contaminants using Portland Cement: A Literature Review. Environmental Reviews. Vol. 14, pp 217 to 255. http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.540.8696&rep=rep1&type=pdf

Patmont, C. R., Ghosh, U., LaRosa, P., Menzie, C. A., Luthy, R. G., Greenberg, M. S., Cornelissen, G., Eek, E., Collins, J., Hull, J., Hjartland, T., Glaza, E., Bleiler, J. and Quadrini, J. (2015), In situ sediment treatment using activated carbon: A demonstrated sediment cleanup technology. Integr Environ Assess Manag, 11: 195–207. doi:10.1002/ieam.1589

Plante, T., et al. (2008). “Equipment and Scale-Up Considerations for In Situ Solidification of MGP Sites,” Gasworks Europe - Redevelopment, Site Management and Contaminant Issues of former MGP’s and other Tar Oil Polluted Sites. Proceedings of MGP 2008 Conference in Dresden, Germany, March 4-6, 2008. http://www.cetco.com/DesktopModules/Bring2mind/DMX/Download.aspx?Command=Core_Download&PortalId=0&EntryId=509

Raj, D.S.S, et al. (2005). Stabilisation and Solidification technologies for the remediation of contaminated soils and sediments: an overview. Land Contamination & Reclamation 13(1):23-48. DOI: 10.2462/09670513.645

Renholds, J. (1998). In Situ Treatment of Contaminated Sediments. Technology Status Report prepared for the U.S. EPA Technology Innovation Office. https://clu-in.org/download/studentpapers/renhold.pdf

U.K. Environment Agency (2004). Review of scientific literature on the use of stabilisation/solidification for the treatment of contaminated soil, solid waste and sludges. Science Report SC980003/SR2. United Kingdom. http://epa.tas.gov.au/documents/southern%20waste%20solutions,%20copping%20-%20scientific%20reviews%20of%20soil%20treatment.pdf

U.S. Environmental Protection Agency (2013). Record of Decision: Gowanus Canal Superfund Site Brooklyn, Kings County, New York. USEPA Region II. New York, New York. USEPA Document 692106.

U.S. Environmental Protection Agency (2013). Use of Amendments for In Situ Remediation at Superfund Sediment Sites. OSWER Directive 9200.2-128FS. April 2013

Werner, D., Higgins, C.P. and Luthy, R.G., 2005. The sequestration of PCBs in Lake Hartwell sediment with activated carbon. Water Research, 39(10), pp.2105-2113.

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