2013 acuity es_casestudy

µg/L

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!

© AcuityES 2013

First things

first…

Interior Building Decontamination

Segregation of Waste for Disposal

Building Demolition

© AcuityES 2013

Soil Boring & Well Installation

Groundwater Sampling

Soil Sampling

First things

first…

© AcuityES 2013

Site Location -- Muncie, IN

Source

Areas

GW

Impacts

© AcuityES 2013

Site Plan for X-Section Line

Site Conditions

First investigation – 2005

AcuityES - 2009

A’

A

© AcuityES 2013

Geologic X-Section

FORMER

BASEMENT

SOURCE AREA

© AcuityES 2013

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

© AcuityES 2013

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

© AcuityES 2013

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

© AcuityES 2013

In Situ Soil Blending

Thorough Mixing to 15’ BGL

© AcuityES 2013

In Situ Soil Blending Completed in 2 weeks

Total FeS = 78,300 gallons

Subsequent stabilization with aglime required

© AcuityES 2013

Confirmation Sampling

© AcuityES 2013

Groundwater Injections – FeS

THE NUMBERS

155 Inject Pts

15 ft ROI

6 wks complete

© AcuityES 2013

Groundwater Injections

Difficult

Injections

Boulder Fields

6’ caliche

(calcified silt)

Lodgement till

© AcuityES 2013

Groundwater

Injections

FeS Injection Totes

35,385 gallons injected Rotosonic Drilling

Top Down Injection – 5ft intervals

© AcuityES 2013

Groundwater Injections

Sensitivity to

the Community

Required

Residential

Hours

© AcuityES 2013

Preferential Flow Paths

15 – 20’ bgl

Sand Unit

© AcuityES 2013

Preferential Flow Paths

20 - 25’ bgl

Sand Unit

© AcuityES 2013

Pre-Treatment Cr+6

State Cleanup

Goal of

100 µg/L

© AcuityES 2013

FeS Reductant Injection

© AcuityES 2013

1st Q Post-Treatment Cr+6

© AcuityES 2013

2nd Q Post-Treatment Cr+6

© AcuityES 2013

3rd Q Post-Treatment Cr+6

© AcuityES 2013

1st Supplemental Injection

© AcuityES 2013

4th Q Post-Treatment Cr+6

© AcuityES 2013

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

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

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

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 Smith Mundell & Associates

Burns & McDonnell CALIBRE

Professional Engineers MWH Global

Malcom Pirnie Carndo MMA

www.acuityes.com

© AcuityES 2013

mailto:[email protected]



2013 acuity es_casestudy

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