Successful Remediation of Residual DNAPL in Tight Materials S. - PowerPoint PPT Presentation

Successful Remediation of Residual DNAPL in Tight Materials S. Markesic, J.Rossabi, J.S. Haselow (Redox Tech, LLC) REDOX TECH, LLC

Overview  Residual DNAPL and difficulties with remediation  Summary of Remediation Techniques Available  Case Studies REDOX TECH, LLC

Residual DNAPL UNSATURATED ZONE SATURATED ZONE (NAPL as the intermediate (NAPL as the non-wetting fluid) wetting fluid) Air NAPL Soil Particles Referring to concentrations where there is no accumulation of free product, but when DNAPL occurs as disconnected singlet and multi-pore globules within the pore spaces. REDOX TECH, LLC

Problems With Treating residual DNAPL in Low Permeable Soils  Often not well delineated  Concentrations can vary considerably in short distances  Distribution/Extraction  Contact  Chemistry (Clays typically have higher Oxidant Demands) REDOX TECH, LLC

Can we Remediate Residual DNAPL in Clay Soils? Yes but….. How long do you have?  What are the cleanup objectives?  What access do I have?  REDOX TECH, LLC

Remediation Approaches Three Types of approaches:  1) Removal  2) Immobilization  3) Destruction REDOX TECH, LLC

Removal Approach  Includes:  Dissolution (increase solubility of product) Requires an extraction  Surfactants, cosolvents, increase process (e.g. dual phase temperature and some way to enhance  Displacement (reduce capillary forces) permeability  Surfactants, cosolvents, increase (e.g. fracturing) temperature  Volatilization (transfer contaminant to vapor phase) Excavation (physically remove) REDOX TECH, LLC

Immobilization Approach  Isolate Source from Surroundings  Barrier Walls  In place encapsulation (cement, bentonite)  Pump and Treat (prevent movement)  Vitrification (solidify) REDOX TECH, LLC

Destruction Approach Chemically Reduce the contaminant  Chemical Oxidation (potassium  permanganate, sodium persulfate, hydrogen peroxide, etc.) Or a Chemical Reduction (e.g. ZVI) combination  Biodegradation  Electron Donor/Acceptor and/or  bacteria culture REDOX TECH, LLC

Problems in Tight Soils “The problem with a destruction approach is that it involves delivering an amendment into a matrix that does not readily allow for dispersion, advection, and diffusion in an acceptable time period” REDOX TECH, LLC

Techniques for Solving Distribution Issues 1) Fracturing Pneumatic or Hydraulic Fracturing GROUT HEAD - ATTACHES TO GEOPROBE RODS " NYLOBRADE FLEXIBLE PVC HOSE PUMP GEOPROBE RIG GEOPROBE RODS GROUND SURFACE SEAL AROUND GEOPROBE RODS WITH BENTONITE AS RODS UNFRACTURED SOIL ARE PUSHED. SEE DETAIL "A" FRACTURED ZONES BEFORE FRACTURE AFTER FRACTURE (Diffusion Controlled) (Connection & Diffusion Controlled) DETAIL "A" VAPOR MOVEMENT IN SOIL MICROSTRUCTURE REDOX TECH, LLC

Techniques for Solving Distribution Issues 2) Tweak Design  Decrease injection spacing (i.e. increase number of points)  Inject at discrete vertical increments to maximize vertical distribution REDOX TECH, LLC

Techniques for Solving Distribution Issues 3) Soil Mixing REDOX TECH, LLC

Techniques for Solving Distribution Issues 4) Electrokinetics (maybe….) • Electokinetic Migration of Permanganate, Lactates, or hydrogen generation via electrolysis REDOX TECH, LLC

Case Study #1  Industrial Site in Ohio  Site soil consisted of silt and clay  TCE in Soil as high as 63,000 ppm  Years of active SVE was ineffective  ISCO with In Situ Soil Blending selected as best approach REDOX TECH, LLC

Case Study #1  3,450 cubic yards from ground surface to 20 ft bgs over 10 day period  78,662 lbs of potassium permanganate (based on stoichiometric demand and background soil oxidant demand)  During soil blending the SVE system was removed  Project completed for $286,700 (~$91 per cubic yard) REDOX TECH, LLC

Case Study #1  41 post blending soil samples were collected Pre Treatment (mg/kg) Post Treatment (mg/kg) Remedial Goal (mg/kg) Maximum Average Maximum Average Area A 4,200 226 390 265 Area B 583 155 380 121 1,948 Area C 63,000 902 1,300 302 REDOX TECH, LLC

Case Study #2  Industrial Site in Illinois  Vadose Zone application in clays and silts from 4 to 8 feet bgs (500 square ft).  TCE in Soil as high as 10,000 ppm  Prior mixing using a conventional backhoe with a peroxygen ineffective at achieving remedial target (1,300 mg/kg = soil saturation limit).  Soil concentrations remained at 7,000 ppm REDOX TECH, LLC

Case Study #2  In Situ Soil Blending with Potassium Permanganate selected  Applied 2,670 lbs of Potassium Permanganate  Work completed in one day for $17,500 (~$233 cubic yard) REDOX TECH, LLC

Case Study #2 Trichloroethene (TCE) Oxidation Results 12000 CS-6 (6 to 7 ft bgs) 10000 Concentration (mg/kg) CS-7 (6 to 7 ft bgs) 8000 GP-2-CS (4 o 8 ft bgs) 6000 In Situ Soil Blending 4000 2000 0 9/9/2008 10/29/2008 12/18/2008 2/6/2009 3/28/2009 5/17/2009 7/6/2009 Sample Date REDOX TECH, LLC

Case Study #3  Active Drycleaner in Illinois  Very tight clays at depths from 4 to 20 ft bgs  PCE concentrations in soil as high as 7,000ppm  Majority of impact under the building  Due to existing reducing conditions, active facility, and depth, flexible timetable, selected ERD via injection approach REDOX TECH, LLC

Case Study #3 Limited scale pilot test conducted in 2009 Repeat Application Full scale conducted in 2010. In 2012 Injected 2,900lbs of ABC+. 1,860 gallons injecting at 1 ft Source intervals from 4 to 20 feet bgs. Area (2 gallons per interval). In 2012 conducted follow up Injections within the source area and back alleyway with 700 lbs of ABC+ All 3 events conducted for ~$41k. REDOX TECH, LLC

Case Study #3 Soil PCE Concentrations from areas of Highest Impact (mg/Kg) PCE (mg/kg) • Achieved up to 99 percent POST – 15 Months POST – 8 Months POST-4 Months reduction in multiple areas Reduction • Cleanup Objectives were based Location Depth on Tier 2 modeling showing no PRE migration off site 1 4 6987.2 175 0.687 NA 99.99 7 5649.5 63.1 1.48 NA 99.97 • Site closed in conjunction with 2 4 3219.9 NA NA 0.87 99.97 a groundwater use restriction 7 4209.2 NA NA 6.8 99.84 3 4 150 <0.128 42.5 NA 71.67 REDOX TECH, LLC

Case Study #3 Groundwater Concentrations (mg/L) MW-11 MW-11 PCE PCE TCE TCE Cis- Cis- VC VC DCE DCE Pre Pre 31.74 31.74 0.437 0.437 3.659 3.659 0.014 0.014 Post (4-months) Post (4-months) 1.6 1.6 0.298 0.298 4.48 4.48 <0.05 <0.05 MW-13 MW-13 PCE PCE TCE TCE Cis- Cis- VC VC DCE DCE Pre Pre 41.6 41.6 0.261 0.261 0.799 0.799 0.01 0.01 Post (4-months) Post (4-months) 5.7 5.7 9.33 9.33 105 105 0.202 0.202 MW-12 PCE TCE Cis- VC DCE Pre 24.5 0.261 0.799 <0.002 Post (4-months) <0.01 <0.01 0.472 1.21 REDOX TECH, LLC

Summary Remediation of residual DNAPL in low permeable sediments is possible, however the cleanup objectives, time to complete, and accessibility will ultimately define success MCLs difficult if unlikely, but reduction of mass to levels where Tier 2 criteria can be applied is manageable Single application success is rare. Multiple applications should be expected. REDOX TECH, LLC

Thank You Questions? Steve Markesic (630) 705-0390 markesic@redox-tech.com REDOX TECH, LLC