Surfactant-Enhanced In Situ Chemical Oxidation (SISCO TM ) for Remediation of Manufactured Gas Plant Residuals

Transcription

1 Surfactant-Enhanced In Situ Chemical Oxidation (SISCO TM ) for Remediation of Manufactured Gas Plant Residuals George Hoag 1 John Collins 1 Kenneth Huang 1 Amine Dahmani 2 Lawrence Liebs 3 Theodore Leissing 3 1 VeruTEK Technologies, 628 Hebron Avenue, Building 2, Suite 505, Glastonbury, CT Spectrum Analytical, Agawam, Massachusetts 3 KeySpan Energy, Brooklyn, New York Problem Statement Multiphase NAPL Multiple surface types Low solubility contaminants Chemistry and physics challenges 1

2 Lessons Learned from Old Conceptual Model Practical: MGP Soils are extremely complex there must be a site-specific strategy considering the chemistry and physics of the remedy: COC, phase, stratigraphy, etc. Theoretical: Surface desorption/oxidation must be considered as two discrete phenomena: (1) surface cosolvent/surfactant solubilization (2) aqueous oxidation Objectives of Treatability Study and Pilot Test Must show sufficient reduction of multiphase source material that results in significant decreases in groundwater COC flux; Show control of surfactant solubilization reaction - treatability test and field; Show control of oxidation reaction - treatability test and field; Show control of surfactant/oxidant transport in the field. 2

3 Conceptual Model for SISCO of MGP-type NAPLs Increase PAH Solubility with Either Cosolvent/Surfactant Mixtures Apply In Situ Chemical Oxidation (ISCO) to Destroy Dissolved COCs If Rate of Solubilization Increases then Rate of ISCO Increases Decrease Time Needed For ISCO to Work in Leaching COCs from NAPL Phase Decrease Cost by Decreasing Time Required and Use Less Chemical Note: SISCO - Surfactant Enhanced In Situ Chemical Oxidation Controlling Solubilization Chun-Huh Relationship: interfacial tension (IFT) is inversely proportional to the square of the solubilization potential; Trade-off between high IFT and preventing mobilization Treatability work began with dilute surfactant concentrations just above CMC; additional work investigated higher surfactant concentrations 3

4 Cosolvent/Surfactant Screening Critical Micelle Concentration Critical Micelle Concentration 4

5 Cosolvent/Surfactant Selection Batch Naphthalene Yield Treatment Type Surfactant Only Groundwater Alfoterra 53 Alfoterra - 53 Alfoterra - 53 Alfoterra - 53 Alfoterra 55 Alfoterra 4PO Type - Cosolvent/Surfactant Citrus Burst 1 Citrus Burst 1 Citrus Burst 1 Citrus Burst 1 E-Z-Mulse Citrus Burst 2 Treatment Concentration (mg/l) Naphthalene Extracted (ug/l) ,486 11,575 13, ,053 14,087 14,524 17,363 52,416 41,987 13,595 44,881 Batch Equilibrium Soil Slurry Results 5

6 Effect of Persulfate on IFT Effect of Surfactant on Surface Tension Batch Tests Task VII Surface Tension (dynes/cm) g/l SP mg/L CB2 50 g/l SP mg/L CB3 50 g/l SP mg/L A lf53 50 g/l SP mg/L CB mg/l Fe(II)EDTA 50 g/l SP mg/L CB mg/l Fe(II)EDTA 50 g/l SP mg/L A lf mg/l Fe(II)EDTA day COCs in Soil, Persulfate Soil Slurry Test 2.00E E E E-03 SVOCs ring SVOCs 2-3 ring SVOCs 4-5 ring SVOCs E-03 mol/kg 1.00E E E E E E+00 Day 0 (SO) Day Day 30 Reaction Data (SO) 6

7 COCs in Soil, Persulfate+Fe(II)EDTA, CB1 Soil Slurry 2.00E E E-03 SVOCs ring SVOCs 2-3 ring SVOCs 4-5 ring SVOCs E E-03 mol/kg 1.00E E E E E E+00 Day 0 (SO) Day Day 30 Reaction Data (SO) Conclusions of Batch Tests Alfoterra and CB solubilize VOCs CB solubilizes VOCs and SVOCs Persulfate is effective in destroying VOCs and SVOCs. Increasing Persulfate concentrations increase IFT except CB3 7

8 Column Study Results Persulfate Breakthrough in Soil Columns R=PVpersulfate/PVConductivity where PV is concentration R= (values obtained from plots below) Col 1: Na2S2O8 (50 g/l) Col 2: Na2S2O8 (50 g/l)-fe(ii)-edta (250 mg/l-1129 mg/l) Col 3: Na2S2O8 (50 g/l)+fe(ii)-edta (250 mg/l-1129 mg/l)+alf 53 (500 mg/l) 8

9 9 Column Effluent COC Concentrations Column Effluent COC Concentrations (Alfoterra-53/Persulfate/EDTA) (Alfoterra-53/Persulfate/EDTA) Fluorene Fluorene Dibenzofuran Dibenzofuran Bis(2- Bis(2- ethylhexyl)phthalate ethylhexyl)phthalate Benzo Benzo (a) (a) anthracene anthracene Naphthalene Naphthalene Methylene Methylene chloride chloride Chloroform Chloroform Butanone 2-Butanone Acetone Acetone COC/Day COC/Day Column Effluent Concentrations Column Effluent Concentrations CB3-Persulfate-EDTA CB3-Persulfate-EDTA Lead Lead Nickel Nickel Copper Copper Chromium Chromium Column Column Effluent Effluent Concentration Concentration (mg/l) (mg/l) Ambient Ambient Water Quality Water Quality Criteria Criteria (mg/l) (mg/l) Metals Metals

10 Removal of COCs in the Soil Columns COC removal, Persulfate Column Test 7.E-03 6.E-03 VOCs SVOCs TICs Molar concentration (mol/kg soil) 5.E-03 4.E-03 3.E-03 2.E-03 1.E-03 0.E+00 Day 0 Day 30 Day 10

11 Molar concentration (mol/kg soil) 7.E-03 6.E-03 5.E-03 4.E-03 3.E-03 2.E-03 1.E-03 COC Removal, Persulfate+Fe(II)EDTA, Alf53 Column VOCs SVOCs TICs 0.E+00 Day 0 Day 30 Day 65% less persulfate used with Alf53 than with Persulfate+Fe(II)-EDTA Note: ~ 77.5 mol Persulfate Consumed mol COC Removed with Alf 53 ~ 218 mol Persulfate Consumed mol COC Removed without Surfactant 11

12 Controlling Contact Using Density-Driven Flow 12

13 Density Modeling Conclusions Density Plays a Major Role on Injected Fluid Transport Controlling Density Can Control Lithology Influenced For This Site, 25 g/l and 50 g/l Persulfate Concentrations Recommended Shallow Zone Source Zone Reduction Specific Conductance (TDS) Behaves Like A Tracer Persulfate Will Be Slightly Retarded 13

14 Conclusions of the SISCO Treatability Work Cosolvent/surfactant mixtures were controlled did not mobilize NAPL and effectively solubilized NAPL. Persulfate-EDTA mixtures persisted in solution and effectively destroyed solubilized COCs. No negative interactions were observed between cosolvent/surfactants and oxidants in coelution. SISCO technology effectively solubilized and oxidized different NAPL fractions. Dissolved Metal concentrations in effluent were very low. SISCO lowers cost of persulfate application. Proposed Treatment for OU-1 Pilot/OU-4 IRM is Citrus Burst 3/Persulfate/Fe 2+ -EDTA. Kinetic limitations of ISCO were overcome with SISCO. SISCO can be used for MGP contaminant source control. 14