PILOT TESTING AND FULL-SCALE ISCO REMEDY DESIGN FOR DEEP BEDROCK AQUIFER

Transcription

1 PILOT TESTING AND FULL-SCALE ISCO REMEDY DESIGN FOR DEEP BEDROCK AQUIFER Second Annual RE3 Conference January 27-29, 2014, Philadelphia, PA Presented By: Omer Uppal, Brian Blum, C.P.G., LSRP, Stewart Abrams, P.E., Erica Sterzinar, Annie Lee, and Matthew Ambrusch

2 PRESENTATION OUTLINE Site Background Remedial Approach Phase I Pilot Test Injection Implementation Testing Results Phase II Pilot Test Hydraulic Fracturing Injection Implementation Testing Results Synopsis Conclusions Proposed Full-Scale ISCO Remedy Design

3 SITE BACKGROUND 98 Acre Former Industrial R&D Facility Trichloroethene (TCE) impacts in soil and groundwater Groundwater concentrations of TCE up to 59,000 ppb (PIW-1B, Nov 2011) Bulk of TCE impacts in the intermediate bedrock zone 155 tons of source area soil removed in 2006 Groundwater Flow Direction Extent of TCE Plume (1 ppb)

4 SITE GEOLOGY Unstratified Glacial Deposits Bedrock (Diorite) Diorite fragments from well drilling Photographer: Siim Sepp, 2005, Source: Wikipedia

5 REMEDIAL APPROACH Why Potassium Permanganate? Bedrock expected to have low SOD ( g/kg), enabling chemical oxidation to be more cost effective Known to be effective for removal of chlorinated ethenes 2KMnO 4 + C 2 HCl 3 2CO 2 + 2MnO 2 + 3Cl - + H + + 2K + Relatively short remedial timeframe MnO 4 - Relatively long subsurface half-life (months to years) Permanganate MnO H + + 3e - MnO 2(s) + 2H 2 O E = 1.70 V

6 PHASE I ISCO PILOT TEST 3 Injection Wells: Shallow bedrock Intermediate bedrock deep bedrock

7 FIELD IMPLEMENTATION Automated Portable Bulk Feed System (Vironex)

8 INJECTION VOLUMES * 97% of solution injected into the deep bedrock zone

9 INJECTION SUMMARY 6,081 gallons of 2.5% potassium permanganate 1,260 lbs of oxidant Three day operation

10 INJECTION OBSERVATIONS Shallow and Intermediate Bedrock: No measureable flow at injection pressures up to 100 psi Deep Bedrock: Able to inject at flow rates ranging from 5 to 22 gpm at a pressure up to 60 psi

11 RADIUS OF INFLUENCE Color (Permanganate = Purple) Observed pink water at MW-12C Groundwater Mounding Observed groundwater mounding at MW-12C, MW- 16B, MW-17B and MW-12D. *Radius of influence for the deep zone is at least 25 feet

12 PHASE I TESTING RESULTS Analytical Results: 99% reduction in TCE at PIW-1C, where the majority of the solution was injected 62% reduction in TCE at MW-12C, the directly downgradient deep monitoring well

13 PHASE I TESTING RESULTS Geochemical Parameters: ORP ph

14 PHASE I TESTING RESULTS ISCO is a feasible remedial technology for the site. Concentrations did not decrease significantly due to the inability to inject in the intermediate bedrock zone. Hydraulic fracturing needed to achieve reasonable injection rates in the intermediate bedrock zone (Phase II)

15 Objectives: PHASE II ISCO PILOT TEST Obtain injection flow-pressure relationships for fullscale remedial design Evaluate strategies to increase chemical distribution Evaluate effectiveness of hydraulic fracturing to facilitate injection in the intermediate bedrock zone

16 FIELD IMPLEMENTATION Methodology and Operation: Installed an additional intermediate injection well (PIW- 2B) Hydro-fractured PIW-2B Injected 2,000 gallons of 2.5% KMnO 4 (452 lbs) in PIW-2B

17 HYDRAULIC FRACTURING OVERBURDEN WEATHERED BEDROCK OVERBURDEN WEATHERED BEDROCK DIORITE DIORITE Fracturing of rock by a pressurized liquid Increases connectivity of aquifer and well yield Performed at PIW-2B at bgs, where highest TCE concentrations observed, by Northeast Water Production, Inc. Direct hydraulic connection was observed, as a function of water level fluctuations, between PIW-2B and PIW-1C following hydro-fracturing.

18 INJECTION OBSERVATIONS Hydraulic fracturing can achieve flow rates of up to 15 gpm at pressures less than 50 psi. Hydraulic influence was observed at distances up to 125 feet during injection. Groundwater daylighting was observed at PIW-1C. Visual evidence of permanganate solution in PIW-1A

19 PHASE II TESTING RESULTS Oxidant distribution at distances up to 125 feet downgradient Oxidant was present at several wells during the post injection sampling round No indication of rebound at PIW-1B Notes: -- = Sample not collected Sampled via passive diffusion bag (PDB) samplers NJDEP GWQS for TCE = 1 ppb

20 PHASE II TESTING RESULTS ISCO is feasible for the intermediate bedrock zone. Hydro-fracturing can significantly enhance oxidant injection rates and distribution in the subsurface. A larger scale injection well network will be more effective in distributing oxidant and reducing TCE concentrations.

21 FULL-SCALE ISCO REMEDY DESIGN Remedial Strategy: Installation of six additional intermediate bedrock zone injection wells, one extraction well Hydraulic fracturing of select injection wells ISCO with NaMnO 4 Groundwater extraction at select monitoring wells along the downgradient site boundary while injecting oxidant Push-Pull ISCO Approach

22 PUMP/WELL YIELD TESTING Performed in April 2013 at seven monitoring wells to verify achievable extraction rates that can be sustained during ISCO injection. Tests Performed: 1. Specific capacity (step-drawdown) aquifer pumping tests Flow rates at individual wells ranged from 0.15 to 1.5 gpm 2. Constant-rate aquifer pumping test Conducted at seven wells simultaneously at 5 gpm (combined pumping flow rate)

23 PUMP/WELL YIELD TESTING RESULTS

24 FULL-SCALE ISCO DESIGN Total mass of 40% NaMnO 4 = 61,100 lbs Target NaMnO 4 injection solution concentration = 7.5% to 10% Total injection volume = 27,400 to 37,200 gallons Design injection rate = 10 gpm (over 6 hours/day) Design extraction rate = 3 gpm (over 8 hours/day) Implementation Planned for Summer 2014

25 FULL-SCALE ISCO DESIGN

26 ISCO EQUIPMENT AND MANIFOLD LAYOUT

27 QUESTIONS? Source: Google Maps