PILOT TESTING AND FULL-SCALE ISCO REMEDY DESIGN FOR DEEP BEDROCK - - PowerPoint PPT Presentation

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

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

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

Extent of TCE Plume (1 ppb)

Groundwater Flow Direction

• Unstratified Glacial Deposits
• Bedrock (Diorite)

SITE GEOLOGY

Photographer: Siim Sepp, 2005, Source: Wikipedia Diorite fragments from well drilling

REMEDIAL APPROACH

Why Potassium Permanganate?

• Bedrock expected to have low SOD

(0.1-0.65 g/kg), enabling chemical

• xidation to be more cost effective
• Known to be effective for removal of

chlorinated ethenes

• Relatively short remedial timeframe
• MnO4
• Relatively long subsurface

half-life (months to years)

2KMnO4 + C2HCl3  2CO2 + 2MnO2 + 3Cl- + H+ + 2K+

Permanganate MnO4

• + 4H+ + 3e- → MnO2(s) + 2H2O

E° = 1.70 V

PHASE I ISCO PILOT TEST

3 Injection Wells:

• Shallow bedrock
• Intermediate bedrock
• deep bedrock

FIELD IMPLEMENTATION

Automated Portable Bulk Feed System (Vironex)

INJECTION VOLUMES

* 97% of solution injected into the deep bedrock zone

INJECTION SUMMARY

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

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

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

PHASE I TESTING RESULTS

Analytical Results:

• 99% reduction in TCE at PIW-1C, where the majority
• f the solution was injected
• 62% reduction in TCE at MW-12C, the directly

downgradient deep monitoring well

PHASE I TESTING RESULTS

Geochemical Parameters:

ORP pH

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)

PHASE II ISCO PILOT TEST

Objectives:

• Obtain injection flow-pressure relationships for full-

scale remedial design

• Evaluate strategies to increase chemical distribution
• Evaluate effectiveness of hydraulic fracturing to

facilitate injection in the intermediate bedrock zone

FIELD IMPLEMENTATION

Methodology and Operation:

• Installed an additional

intermediate injection well (PIW- 2B)

• Hydro-fractured PIW-2B
• Injected 2,000 gallons of 2.5%

KMnO4 (452 lbs) in PIW-2B

HYDRAULIC FRACTURING

• Fracturing of rock by a pressurized liquid
• Increases connectivity of aquifer and well yield
• Performed at PIW-2B at 100-150 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.

OVERBURDEN OVERBURDEN WEATHERED BEDROCK WEATHERED BEDROCK DIORITE DIORITE

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

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

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

• xidant and reducing TCE

concentrations.

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 NaMnO4
• Groundwater extraction at select monitoring wells along

the downgradient site boundary while injecting oxidant “Push-Pull ISCO Approach”

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)

PUMP/WELL YIELD TESTING RESULTS

• Total mass of 40%

NaMnO4 = 61,100 lbs

• Target NaMnO4 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

FULL-SCALE ISCO DESIGN

FULL-SCALE ISCO DESIGN

ISCO EQUIPMENT AND MANIFOLD LAYOUT

Source: Google Maps

QUESTIONS?