recovery 5.0: a contaminated sediment-water interaction …

US Army Corps of EngineersBUILDING STRONG®

Carlos E. Ruiz and Terry K. GeraldEnvironmental Laboratory

U.S. Army Engineer Research and Development Center

RECOVERY 5.0: A Contaminated Sediment-Water Interaction Model

Tenth International Conference on Remediation and Management of Contaminated Sediments, New Orleans, Louisiana, February 2019

Innovative solutions for a safer, better worldBUILDING STRONG®

Purpose

Evaluate long-term contaminated sediment -water column interactions► Evaluate no action alternative► Evaluate monitored natural recovery► Evaluate capping► Evaluate reactive capping► Evaluate environmental dredging► Evaluate residuals management


Limitations

Steady conditions► Constant residence time/flow rate► Constant suspended solids concentration/TOC► Constant burial rate► Constant bioturbation► Constant decay rates

Uses long-term averages No catastrophic events

► Storm-induced erosion► Flood-induced deposition


Description PC based, user friendly Fully mixed water body

and layered bottom sediments

Time-variable Organic contaminants

database Computes sediment and

water contaminant concentrations and fluxes vs. time


Schematic of RECOVERY 5.0 Processes


Verification/Validation

Compared with analytical solutions Compared with laboratory data Compared with contaminant

transport data from a flooded quarry pit (5 years)

Compared with long-term cap performance data for contaminant isolation (11 years)


Model Improvements

Model formulations► Biodiffusion/bioturbation► User-defined partitioning

• Reversible adsorbed metals • Site specific• DOC facilitated

► Mass transfer across discontinuous sediment layers/interfaces

► Thin layers (reactive amendments and geotextiles)

► Groundwater/advective flow (up to 5cm/day)


RECOVERY 5.0 GUI


RECOVERY 5.0


RECOVERY Testing

Parameter ValueMixed layer thickness (cm) 5Cap thickness (cm) 30Porosity of cap 0.5Specific gravity of cap 2.65Sediment thickness (m) 1Porosity of sediment 0.67Specific gravity of sediment 2.65Settling velocity (m/yr) 126Burial velocity (m/yr) 0.001Molecular diffusivity (cm2/sec) 5x10‐6Biodiffusion coefficient (cm2/sec) 2x10‐5Biodiffusion depth (cm) 0

Three scenarios:• no cap• sand cap• sand cap with groundwater flow (10, 100 cm/yr)


Testing Results0

20406080

1001201400.00E+00 5.00E+02 1.00E+03

Depth (cm)

Pore water concentration (ug/l)

Anthracene

0 Years

50 Years

100 Years

200 Years

0

20

40

60

80

100

120

1400.00E+00 5.00E+02 1.00E+03

Depth (cm)

Pore water concentration (ug/l)

Anthracene

0 Years

50 Years

100 Years

200 Years

100 cm/yr

10 cm/yr


St Louis River Great Lakes Area of Concern (AOC)

Development along the St Louis River (SLR) has contributed to contaminated sediments

► Paper mills► Coal gasification plants► Steel processing

Active in shipping► Iron ore► Coal► Limestone► Grain

Three impairments to the St. Louis River AOC: fish consumption advisory, degradation of the benthos environment and restrictions on dredging.

RECOVERY Application


RECOVERY ApplicationCompound

Maximum Concentration

Detected

Level 1 SQT

Midpoint SQT (Cleanup Level)

Level 2 SQT

UnitsMaximum Hazard Quotient

Total PAHs 131,860 1600 12,300 23,000 ug/kg 10.7Acenaphthene 2,600 6.7 47.85 89 ug/kg 54.34

PCBs 1000 60 370 680 ug/kg 3.08Cadmium 5.4 0.99 2.995 5 mg/kg 1.80Chromium 51.7 43 76.5 110 mg/kg 0.68Copper 250 32 91 150 mg/kg 2.74Lead 544 36 83 130 mg/kg 6.5Mercury 3.3 0.18 0.64 1.1 mg/kg 5

Evaluate the Cap performance using a long‐term contaminant transport model

Model evaluation to compare the surficial contaminant concentration of Slips (represented by the mixed layer or bioactive zone) throughout the 100‐year design life with the SQT Level 1 criteria.


Slip C CapParameter Value

Mixed layer thickness (cm) 10Mixed layer porosity 0.75Cap thickness (cm) ‐‐ Upper and Lower Cap 15 and 30Porosity of cap ‐‐ Upper and Lower

Cap0.55 and 0.50

Specific gravity of cap ‐‐ Upper and Lower Cap

2.48 and 2.51

Sediment thickness (m) 4.02 and

3.99

Porosity of sediment 0.55 and 0.65

Specific gravity of sediment 2.42 ‐2.59

Settling velocity (m/yr) 136Burial velocity (m/yr) 0.001Molecular diffusivity (cm2/sec) 5 x 10‐6

Biodiffusion coefficient (cm2/sec) 2 x 10‐5

Biodiffusion depth (cm) 0


Slip C Results

w/groundwater upwelling of 0.5 cm/day.w/groundwater upwelling of 0.5 cm/day.

w/groundwater upwelling of 0.5 cm/day.


Questions?

CAP IT CAP IT

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