Overburden and Bedrock Remediation Using Activated Carbon Based Injectates Mike Mazzarese AST Environmental, Inc. SMART Remediation Toronto, ON SMART is Powered by: www.vertexenvironmental.ca
Overburden and Bedrock Remediation Using Activated Carbon Based Injectates Mike Mazzarese Senior Engineer AST Environmental, Inc. Remediation Products Inc. (RPI) AST Environmental THE RPI Group International Installer Network 2 1
Activated Carbon Based Injectate Technology Overview Trap and treat concept Contaminants sorb to activated carbon trap Decreases groundwater mass immediately Disrupts groundwater/soil mass equilibrium to help drive desorption Concentrated mass accelerates degradation rates Various degradation mechanisms are used to treat Bioremediation (aerobic/anaerobic) Chemical reduction/oxidation 3 BOS Technologies BOS 1 Specially manufactured activated carbon impregnated with metallic iron Primarily used to treat chlorinated solvents (ethenes, ethanes, methanes) BOS 2 Primarily used to treat petroleum hydrocarbons Product consists of: Activated Carbon Terminal electron acceptors Micro and macro nutrients Consortium of facultative bacteria 4 2
Proof of Concept or Treat Terminal electron acceptor depletion (e.g. NO 3 => NO 2 ) Dissolved Gases (e.g. ethane, ethylene, acetylene) Volatile fatty acid generation (e.g. acetate) Total mass reduction (groundwater + soil) 5 Terminal Electron Acceptor Depletion 8, 1,6 7, 1,4 6, 1,2 Benzene, ppb 5, 4, 3, 2, 1, 8 6 4 TEA, ppm Benzene Nitrate Nitrite Sulfate 1, 2 6 3
Dissolved Gas Generation 7 A Few Comments Before We Continue.. Remediation chemistries work in a beaker/column so why so many failures? Loading/Dosing Contaminant mass distribution is complex and scales with the heterogeneity of the lithology Soil mass contribution is typically underestimated Contact We all know contact is critical to success Assess distribution to confirm design spacing/injection volumes 8 4
Remedial Design Characterization (RDC) A (North) A' (South) Depth below grade (ft) TW-14 TW-13 TW-11 TW-1 TW-6 TW-5 51 87 63 414 1 69 2,862 2 16 85 58 841 3 4 5 6 7 159 1,57 2,43 7,195 841 183 612 3,68 1,247 887 3,71 3,277 8 1,789 2,22 16 1,56 1,18 9 5,433 1,973 1 18 4,191 6 29 11 245 5 37 12 Refusal Refusal 16 3,16 191 8 13 Refusal 14 42 2,515 15 455 116 16 Refusal Refusal 245 17 Refusal Notes: Values are summation of PCE, TCE, cis-1,2 DCE and VC in ug/kg Data generated by RPI Laboratory (Golden, CO) 9 Slurry Application Best Practices Proper equipment and field staff Develop high resolution (surgical) injection plan Assess distribution during pilot test or full scale startup Use implants or nested temp wells and soil coring Be prepared to alter spacing, injection volumes, injection tip geometry, etc. Top down critical to success 18-24 typically Injectate 1 5
Bedrock Applications Portfolio of bedrock applications growing Characterization (geophysics) critical to success Proper packer and pumping system selection will help minimize # of injection wells 11 Monitoring Well Impacts Monitoring wells may be intersected by carbon injectates Methodologies in place to minimize injection effects and rehab wells Some wells may need to be replaced 12 6
Replacement Wells Benzene MW Pairs Baseline (ppb) Last Sampling Event (ppb) % Reduction MW 3 ND 1% 4,26 MW 3R 96 98% MW 6 ND 1% 441 MW 6R 41 91% 13 9 Post Injection Data No Carbon Observed During Injection 14 8 7 6 Nitrate (ppm) 12 1 Sulfate (ppm) 5 8 4 3 6 2 4 1 Nitrite (ppm) 2 1/12/212 1/1/213 1/2/213 1/3/213 1/4/213 1/12/212 1/1/213 1/2/213 1/3/213 1/4/213 14 7
Project Summary #1 Former Retail Gas Station Impacted groundwater within fractured bedrock (schist) and overburden soil Shallow bedrock ~ 3 m bgs The initial objective was to evaluate the performance of BOS 2 injections in bedrock Overburden injections followed in 2nd mobilization Groundwater concentration targets: B = 51 ug/l T = 11 ug/l E = 97 ug/l X = 6,7 ug/l Overburden Injection Area Bedrock Injection Well 15 Remedial Design Characterization Bedrock Open rock borehole (IW 2) installed for characterization and injection Down hole video logging used to identify fractures (6) Clean water pump tests performed at all fractures Determine ability of features to accept fluid and design volumes Samples collected from transmissive zones (4) Transducers placed in nearby wells to assess connectivity Influence observed at all wells within test area (farthest 8 m) with minimal influence in overburden B @ 4.1 m = 81 ppb B @ 4.9 m = 829 ppb B @ 6.5 m = 577ppb B @ 6.7 m = 545 ppb 16 8
Remedial Design Characterization Overburden 4 overburden soil sampling locations selected (sampling every.6 m vertically, 1.6 3.5 ft bgs) Locations converted to temporary piezometers Max Benzene in groundwater = 9.89 ppm (PZ 1) 17 Implementation Bedrock: 1,2 kg BOS 2 (4,32 L) Flow rate = 115 192 lpm Overburden: 87 kg BOS 2 injected into 44 pts on 1.6 m spacing (5,9 L) Site divided into two treatment areas based on RDC soil/gw data Injection Zone = 1.6 3.5 m bgs Flow rate = 115 134 lpm 18 9
Bedrock/Transition Well Data Groundwater Concentration (µg/l) 15, 14, 13, 12, 11, 1, 9, 8, 7, 6, 5, 4, 3, 2, 1, BR Inj OB Inj IW 2 MW 3 MW 27 MW 28 BTEX + MTBE Data 19 Overburden Well Data 3, 27,5 Groundwater Concentration (µg/l) 25, 22,5 2, 17,5 15, 12,5 1, 7,5 5, 2,5 BR Inj OB Inj IW 1 PZ 1 PZ 2 PZ 3 PZ 4 BTEX + MTBE Data 2 1
Benzene Only Data 2,5 Groundwater Concentration (µg/l) 2, 1,5 1, 5 BR Inj OB Inj MW 3 MW 27 MW 28 IW 1 PZ 2 PZ 3 PZ 4 41373.,. 21 Project Summary #2 Former bulk storage facility Extensive excavation (performed by others) BOS 2 pilot test performed 28 Remedial Design Characterization and Full Scale performed 211/early 212 NFA granted after 8 quarters Post injection soil sampling completed to compare against RDC data 22 11
Pilot Test + Full Scale Data 18. Pilot + Full Scale MW 6R Benzene Results 16. 14. 12. [Benzene], mg/l 1. 8. 6. 4. 2.. 28/4/27 9/9/28 22/1/21 6/6/211 18/1/212 2/3/214 Benzene (mg/l) Pilot Test Replacement Well Installed Full Scale 23 Pre and Post Injection Soil Sample Data 24. 22. 2. 18. 16. Full Scale MW 27 Benzene & TVPH Results 18 16 14 12 [Benzene], mg/l 14. 12. 1. [B] soil = 1.9 mg/kg [TVPH] soil = 3,4 mg/kg 1 8 [TVPH], mg/l 8. 6. 4. 2. [B] soil = <.1 mg/kg [TVPH] soil = 3 mg/kg 6 4 2. 22/1/21 1/8/21 26/2/211 14/9/211 1/4/212 18/1/212 6/5/213 22/11/213 Benzene (mg/l) Full Scale TVPH (mg/l) 24 12
Technology Adoption Consultants AECOM/URS Kleinfelder AMEC FW Stantec Antea CH2M Parsons Weston Arcadis ERM +Others Responsible Parties Exxon Mobil BP Shell Chevron 7 11 Conoco Phillips CSX GE Noble Energy DOD/DOE +Others 25 Thank you for your time. Questions? 26 13