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In-Situ Remediation of Hexavalent Chromium, Antimony and Nickel with Sub-Micron (Nano)-Scale Ferrous Sulfide Slurry
Jim V. Rouse, Richard H. Christensen, PhD LPG,
& Steven R. Irvin (AcuityES, Fishers, IN)
© AcuityES 2013
Company’s Primary Focus: • Environmental Liability Consulting (how to manage liabilities) • Site Investigation – Soil, Groundwater, Air • Remediation of contaminated Sites • Expert Witness Testimony
Company’s Secondary Focus: • Environmental Permitting – Air, Water, Waste • Environmental Compliance
Acuity Environmental Solutions
© AcuityES 2013
Presented At: • International Seminar on Remediation and Redevelopment of
Contaminated Sites, Sao Paulo, Brazil • AEHS West Coast Conference, San Diego, CA • USEPA’s Sustainable Remediation International Conference, Amherst, MA • AWPA National Conference, Ft. Lauderdale, FL & Nashville, TN • Midwest States Environmental Consulting Assoc., Indianapolis, IN • Battelle Conference, Monterey, California
In-Situ Remediation of Hexavalent Chromium, Antimony and Nickel with Nano-Scale Ferrous
Sulfide Slurry
© AcuityES 2013
Case Study In… In Situ Geochemical Reduction
Stabilization (i.e., immobilizing) of metal constituents by chemically reducing the metals of concern to less soluble forms through the manipulation of geochemical factors such as:
• pH • Oxidation potential (Eh or ORP) • Complexation • Sorption • Ion exchange
Resulting in the elimination of metallic contaminants by: • Precipitation • Dissolution • Oxidation • Complexation
© AcuityES 2013
Key Project Considerations Competitor’s Proposals for Project included: • Off-site disposal of hazardous soils • 15 - 20 year pump and treat remedy for groundwater • >$8 Million
Note: original estimates based on >50% smaller source area Our Solution: • In Situ remediation of impacted soils and groundwater • Goal: 2 year total remedy - 1/8th the time - • Cost: $4.5 Million - Nearly 50% below competitor’s bids -
© AcuityES 2013
Chrome Plating
Gone Wild!
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First things first…
Interior Building Decontamination
Segregation of Waste for Disposal
Building Demolition
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Soil Boring & Well Installation
Groundwater Sampling
Soil Sampling
First things first…
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Site Location -- Muncie, IN
Source Areas
GW Impacts
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Site Plan for X-Section Line
Site Conditions First investigation – 2005 AcuityES - 2009
A’
A
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Geologic X-Section
FORMER BASEMENT
SOURCE AREA
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Hydrogeology
Unconfined Aquifer Clay to 15 feet (w/stringers) Sands & fine gravels Static Water at 15’ bgl Saturated thickness 5’ in SE to > 25’ in NW
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Soil Impacts
• Two Adjacent Source Areas • 5,400 cubic yards of impact • Perched water sand stringers
7,900 mg/Kg maximum Cr+6
3,600 mg/Kg Cr+6 at 12’ bgl
State Cleanup Goal - 38 mg/Kg
© AcuityES 2013
Groundwater Impacts
Groundwater COCs Cr+6, Sb, As, and Ni
On-Site Cr+6
800,000 µg/L
9,700,000 µg/L
66,000 sq ft (320 ft long) Plume Offsite Cr+6 at 58,800 µg/L
State Cleanup Goal- 100 µg/L Cr+6
© AcuityES 2013
In Situ Chemical Reduction
•Ferrous Sulfate : FeSO4·7H2O
•Ferrous Sulfide : FeS
•Calcium Polysulfide (CPS) : CaSx
•Sodium Thiosulfate : Na2S2O3
•Sodium Metabisulfite : Na2S2O5
•Sodium Sulfite : Na2SO3
•Zero Valent Iron
BENCH TESTED CHEMICALS REDUCTANTS
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Selected Ferrous Sulfide (FeS)
FeS, Hybrid Form (aka precipitated pyrite)
Liquid suspension of 7% FeS FeS, hybrid - With additional 2% free Sulfide to simulate CaSx Nanoscale: 98% crystals <5 microns Cationic (Iron) 4 H2O + Cr04
2- + 3 Fe2- + 4 OH- 3 Fe(OH)3+ Cr(OH)3 (Solid) Anionic (sulfide) 17 H2O + 8 Cr04
2- + 3 HS- 3 S + 8 Cr(OH)3 (Solid) + 12 OH-
© AcuityES 2013
In Situ Soil Blending
Dual Axis Blender – 15’ Plunge Total Area – 130’ x 110’
GPS Grid Network – 10’ x 10’ (100’ x 70’ to 15’) & Shallow to 5’
Computerized Dosing
© AcuityES 2013
In Situ Soil Blending
Dual Axis Blender
FeS injection/mixing
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In Situ Soil Blending
Thorough Mixing to 15’ BGL
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In Situ Soil Blending Completed in 2 weeks Total FeS = 78,300 gallons Subsequent stabilization with aglime required
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Confirmation Sampling
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Groundwater Injections – FeS
THE NUMBERS
155 Inject Pts
15 ft ROI
6 wks complete
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Groundwater Injections
Difficult Injections
Boulder Fields
6’ caliche
(calcified silt)
Lodgement till
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Groundwater Injections
FeS Injection Totes 35,385 gallons injected
Rotosonic Drilling Top Down Injection – 5ft intervals
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Groundwater Injections
Sensitivity to the Community
Required
Residential Hours
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Preferential Flow Paths 15 – 20’ bgl Sand Unit
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Preferential Flow Paths 20 - 25’ bgl Sand Unit
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Pre-Treatment Cr+6
State Cleanup Goal of
100 µg/L
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FeS Reductant Injection
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1st Q Post-Treatment Cr+6
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2nd Q Post-Treatment Cr+6
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3rd Q Post-Treatment Cr+6
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1st Supplemental Injection
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4th Q Post-Treatment Cr+6
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5th Q Post-Treatment Cr+6
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6th Q Post-Treatment Cr+6
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7th Q Post-Treatment Cr+6
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2nd Supplemental Injection
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8th – 10th Q Post-Treatment Cr+6
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Antimony Treatment Antimony Concentrations: Detected in 25 monitoring wells on-Site up to 30,000 µg/L off-Site up to 4,700 µg/L State Industrial Cleanup level - 41 µg/L State Residential Cleanup Level - 6 µg/L Goal for Antimony: Fixate onto Goethite (FeO(OH)) or Precipitate as stibnite (Sb2S3)
© AcuityES 2013
Pre-Treatment Antimony
State Cleanup Goal of 6 µg/L
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FeS Reductant Injection
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1st Q Post-Treatment Antimony
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2nd Q Post-Treatment Antimony
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3rd Q Post-Treatment Antimony
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1st Supplemental Injection
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4th - 10th Q Post-Treatment Antimony
All results less than method
detection level of
6 µg/L
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Nickel Treatment Nickel Concentrations Detected in 10 wells exceeding cleanup levels off-Site up to 4,100 µg/L on-Site up to 50,000 µg/L State Industrial Cleanup level – 2,000 µg/L State Residential Cleanup Level - 730 µg/L Goal for Nickel: Fixate as: westerveldite ([FeNiCo]As) or pentlandite (FeNiS)
© AcuityES 2013
Pre-Treatment Nickel
State Cleanup Goal of
730 µg/L
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FeS Reductant Injection
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1st Q Post-Treatment Nickel
All results less than method
detection level of
50 µg/L
No subsequent detections
© AcuityES 2013
Arsenic Arsenic – Pre-treatment As detected in 13 wells @ concentrations of 11 µg/L to 360 µg/L 10th Quarter Sampling results: only 2 wells @ 11 & 12 µg/L Goal for Arsenic Fixate as: orpiment (As2S3) or arsenopyrite (FeAsS)
© AcuityES 2013
The Site Today
© AcuityES 2013
ISCR Benefits 1. In situ soil blending eliminated need for off-Site
hazardous waste disposal. (> 10,000 Tons)
2. In situ groundwater geochemical reduction eliminated need for prolonged pump and treat.
3. In situ geochemical reduction reduced time period of remediation from > 15 years to about 2 years.
© AcuityES 2013
CONTACT Richard H. Christensen, PhD, LPG – [email protected]
Steven R. Irvin – [email protected] Jim V. Rouse – [email protected]
317-570-4919
Past Teaming Partners
CDM Mundell & Associates Burns & McDonnell CALIBRE Professional Engineers MWH Global Malcom Pirnie V3 Consultants
www.acuityes.com © AcuityES 2013
