1 Section 4- Characterization  Characterization is 95% of the Success of ISCO  Develop a complete and comprehensive Conceptual Site Model  ISCO is a Mass Destruction Technology  Successful Treatment must Identify both target and non target analytes and contain all phases of Mass  Know Flow paths within soil Structure

2 Conceptual Site Model Development  Characterization of nature and mass of contaminants present Sorbed Dissolved Free product phases  Subsurface geology, site topography, aquifer geochemistry  Identification of major migration pathways for contaminants of concern (COC) Surface and subsurface structures Underground utilities  Direction / gradient / velocity of groundwater flow  Surface water features / uses, and potential receptors in the area First and most important step in remediation project includes

3 Contaminant Mass PSH, Sorbed, Dissolved Appl. Well Existing MW Number of Wells Total VOCs (average for all Areas)ppm850 Area x7510 TICppm0 Area x130 (includes Area 1)35 TPH/Cosolvents ppm 0Area x Multiply the number of wells times the reagent requirement Total Contaminant Loadppm850

4  Contamination mass exists in four phases in the contaminated zone Soil gas Sorbed Dissolved Non-aqueous phase liquid (NAPL) or phase-separated  Geochemistry, partitioning coefficient (K ow ) determines the relationship between phases in the saturated zone  Majority of mass (normally >80%) is sorbed and phase-separated Total Mass Evaluation Nature of Contamination Graphic source: Suthersan, 1996

5 Total Mass Evaluation Importance of Mass Calculations  Evaluate pre- and post- total contaminant mass  Sorbed and non-aqueous phase mass converts to dissolved during treatment and until site reaches post treatment final equilibrium  Possible “rebound” causes Dissolution of sorbed or non-aqueous phase Inadequate site characterization Change in groundwater flow direction  Decrease in total mass may not be reflected in short-term dissolved concentrations Electroconductivity Diagram

6 Treatment Volume Estimate CleanOX Appl. Well Existing MW Radius of Influenceft20 Area of Influencesft1258 Screen Depth, topft5 Screen Depth, bot.ft30 Total Treatment Volumecft31450 Total Groundwater Volumegal70583 Total Groundwater Weightlb588744

7 Value of Data Quantity vs. Certified Analytical Data  ISCO requires contaminant delineation, precise concentration data quality not as critical as for closure confirmation  References – available at under “Guidance Documents” ITRC Technical and Regulatory Guidance for the Triad Approach: A New Paradigm for Environmental Project Management (SCM-1, December 2003) ITRC Strategies for Monitoring the Performance of DNAPL Source Zone Remedies (DNAPLs-5, August 2004)

8 Site Geochemistry/Geology UnitsValue Range LimitsNotes Porosity%0.3 Permeabilitymd ,000 pHs.u.6.5<8.5 Specific conductanceuS/cm Groundwater temperature 0F0F Groundwater velocityft/day

9 Oxidant Demand Nomenclature  Natural oxidant demand (NOD)  Soil oxidant demand (SOD)  Total oxidant demand (TOD)  Natural organic matter (NOM)  Standard laboratory measurements of oxidizable matter in groundwater include Chemical oxygen demand (COD) Total organic carbon (TOC) Total inorganic carbon (TIC)

10 Site Geochemistry/Geology UnitsValue Range LimitsNotes Redox potential (ORP)mV070 - (-70) Grain sizemm % pt. Dissolved oxygen (DO)ppm TDSppm TOC in groundwaterppm4<40 Hydroxyl scavengerppm100<400 Well diameterinch11/2 new SS

11 Conditions that Require Special Consideration  Low permeable soils  Deep aquifers  LNAPL/DNAPL  Confined formations  Swamps or high organic soils  Old landfills and dumps  River embankments  Under buildings

12 Surface Water Body Pipeline I-55 Limited Access Highway Private Property Access Only No Utilities Flood Prone Area with Dirt Roads Special Site Model Considerations

13 Lithology and Flow Path  Borings need to be properly installed by experienced personnel, which is contrary to reimbursement program pricing  Fine Sand lenses and variations in permeability are difficult to determine with Geoprobe programs  Wells need to be properly screened and developed (not three well volumes as in PST programs)  Confining layers are critical

14 Conceptual Site Model Target Interval Identification Target Interval Contaminant Mass Soil Conductivity