Surfactant Flushing

2009 Pilot Study2009 Pilot StudyFueling Point – Military SiteFueling Point – Military Site

Northeastern USANortheastern USA

Jeffrey H. HarwellAsahi Glass Chair of Chemical EngineeringThe University of OklahomaPrincipalSurbec Environmental, LLC

Background

Jet fuel spill discovered in 2006Jet fuel spill discovered in 2006 Probably happened in 2001Probably happened in 2001 Depth to water 44 ftDepth to water 44 ft Sandy aquifer - 20% siltSandy aquifer - 20% silt Drinking water wells within ¼ mile but in Drinking water wells within ¼ mile but in

deeper aquiferdeeper aquifer Estimated 350,000 to 700,000 gal spillEstimated 350,000 to 700,000 gal spill

Pilot Study ObjectivesSurfactant Enhanced Aquifer Remediation (SEAR)

• Evaluate effectiveness and efficiency• Demonstrate chemical/hydraulic control• Generate design for full-scale implementation

• Within the LNAPL plume • generally up-gradient• minimize recontamination

• No impact to existing soil vapor extraction system

Pilot Study Location

Treatability Study

• Surfactant system designSurfactant system design• Provide proof of concept Provide proof of concept

• Geochemistry considerationsGeochemistry considerations• Heterogeneity issuesHeterogeneity issues

• Optimization of injection strategyOptimization of injection strategy

Step 1: Formulate Microemulsion

MonomerMonomer

OrganicContaminant

Micelle

Increasing Salinity

I III II

VialsSurf. A(wt%)

Surf. B(wt%)

Salt A(wt%)

Salt B(wt%)

Middle

Phase

Aqueous

Phase

NAPLPhase

Winsor

TypeBA-1 0.75 0.19 1.5 0.06 No Hazy Yellow IBA-2 0.75 0.19 1.5 0.10 Yes Clear Yellow IIIBA-3 0.75 0.19 1.2 0.10 Yes Clear Yellow IIIBA-4 0.75 0.19 1.3 0.10 Yes Clear Yellow IIIBA-5 0.75 0.19 1.4 0.10 Yes Clear Yellow IIIBA-6 0.75 0.19 1.6 0.10 Yes Clear Yellow IIIBA-7 0.75 0.19 1.7 0.10 Yes Clear Yellow IIIBA-8 0.75 0.19 1.8 0.10 Yes Clear Yellow IIIBA-9 0.75 0.19 1.9 0.10 Yes Clear Yellow III

BA-10 0.75 0.19 2.0 0.10 Yes Clear Yellow IIIBA-11 0.75 0.19 2.1 0.10 Yes Clear Yellow III

BA-12 0.75 0.19 2.2 0.10 Yes ClearHazy

YellowIII

BA-13 0.75 0.19 0.8 0.10 No Hazy Yellow IBA-14 0.75 0.19 1.5 0.10 Yes Clear Yellow IIIBA-15 0.75 0.19 1.6 0.10 Yes Clear Yellow IIIBA-16 0.75 0.19 1.7 0.10 Yes Clear Yellow IIIBA-17 0.75 0.19 2.5 0.10 Yes Clear Yellow III

Table 1 Microemulsion Phase Behavior

Step 1: Formulate Microemulsion

Mixture of food grade anionic surfactants

Table 2 Sorption Studies

Summary of Sorption Test Ft. Drum

Soil: Ft. Drum sediment - dryed & sieved with #10 (d < 2.0 mm)Water: DI wateri = initialf = finalQ = (mass sorbed/mass media) = (Ci - Ceq)V / MCi = Initial Concentration of surfactantCeq = Final Concentration of surfactantV = volume of solutionM = mass of media

Batch M V [Surf A],i [Surf B],i [Total Surf],i [Surf A],f [Surf B],f [Total Surf],f Q, Surf A Q, Surf B Q, Total Surf %, loss of # of surf PV to be applied Name g ml mg/L mg/L mg/L mg/L mg/L mg/L mg/g mg/g mg/g total surf to compensate for the loss

AD022409-1 0 15 6652.8 2038.4 8691.2 6652.8 2038.4 8691.2 - - - 0.0 1.00AD022409-2 5.0015 15 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 - -AD022409-3 5.0025 15 6652.8 2038.4 8691.2 6384.0 1980.1 8364.1 0.8 0.2 1.0 3.8 1.04AD022409-4 5.0011 15 3326.4 1019.2 4345.6 3270.4 984.7 4255.1 0.2 0.1 0.3 2.1 1.02AD022409-5 5.0032 15 665.3 203.8 869.1 406.6 199.3 605.8 0.8 0.0 0.8 30.3 1.30Note: The analytical results of surfactant A are in the range of ±10%.

Step 2: Verify Adsorption Losses are Reasonable

Very sandy soil; very low adsorption

Sample[Surf.

A][Surf.

B][Salt A] [Salt B]

[Calcium Chloride]

Presence of Precipitate

Presence of

SeparationID wt% wt% wt% wt% ppm Yes/No Yes/No

P-0 0.75 0.19 1.6 0.1 0 No Yes*P-100 0.75 0.19 1.6 0.1 100 No Yes*P-300 0.75 0.19 1.6 0.1 300 No YesP-500 0.75 0.19 1.6 0.1 500 No YesP-800 0.75 0.19 1.6 0.1 800 No Yes

Table 3 Precipitation and Phase Separation Tests

Note: * No phase separation within the first day of observation

Step 3: Examine Sensitivity to Phase Separation

SolutionPolyme

r μ(Average)

(ppm) (cp)NAPL - 1.4181

Surfactant/Polymer (S/P) Solution

0 1.4046100 1.6949300 1.9367500 2.7654800 3.3162

1,500 3.7507

Surfactant/Polymer/Alkaline (S/P/A) Solution

0 1.4046300 2.0927500 2.6748500 2.6748800 3.9592

1,500 4.2944

Table 4 Viscosity of Different Solutions

Note: (average) is the average viscosity shown in the

unit of centipoise (cp)

Step 4: Mobility Ratio

Table 5 Summary of 1-D Column Tests*S: surfactant, P: polymer, A: alkaline; PV = pore volume**yellow highlighted: the optimal surfactant candidate based on the performance of NAPL recovery and the recovery mechanism (mainly mobilization)

Step 5: Optimize Injection Sequence

Pilot Study Overview

• Footprint was < 1/8 acre; well spacing of 25 ft.• 2 pore volumes of surfactant at 0.94 wt %• 2 nine-spot patterns• Submersible pumps recover NAPL/water/surfactant• Process equipment

• oil/water separator• injection mixing tanks/pumps • injection/extraction manifolds• influent/effluent pumps• carbon vessels

Mixing & Holding Tanks, O/W Separator, GAC Canisters

Site Site MapMap

Timeline

• Pre-Flush – 1 pore volume– 31 Aug 09 – 6 Sep 09– Set BioTraps on 3 Sep 09– Tracer (NaBr) injected 4 – 5 Sep 09

• Surfactant Flush – 2 pore volumes– 6 – 21 Sep 09 – Groundwater sampled on 10 and 17 Sep 09– Surfactant first observed

– EX-02 and OWS on 20 Sep 09– EX-01 on 23 Sep 09

Timeline

• Post Flush - 5 pore volumes– 21 Sep 09 – 1 Nov 09– Applied vacuum on extraction wells on 25 Sep 09– Reconfigured injection/extraction on 20 Oct 09– Groundwater sampled on 1 Oct 09 and 2 Nov 09 – BioTraps 7 Oct 09– Injected remaining treated water 3 – 6 Nov 09 to empty tanks

Size: 18,000 Gallons

Transfer Pump

Mixing Tanks

Mixing TanksMixing Tanks

Size: 18,000 GallonsMixer with propeller

Injection Manifold

Flow Meter

Flow Control Unit

Flow Meters and Flow Controllers

Remediation and Monitoring Wells

Oil/Water Separator 45 min. Residence Time

Surfactant Concentrate 330 Gallon Totes

Added Manually to Mixing Tank

Phase Behavior Phase Behavior TestTest

2.5 min

3 min

NaCl: 0.3-1.7% with 0.1% increment

Quality Control Check

Phase Behavior TestPhase Behavior Test

1 hour

NaCl: 0.3-1.7% with 0.1% increment

Data Assessment

• Pre-Pilot Conditions– API Model estimated 2,300 gal LNAPL

• Results– Total LNAPL Recovery was 2,740 gal– API Model estimated140 gal remained

LNAPL Thickness/Distribution

API Model

Soil Sampling Results - Upper

Soil Sampling Results - Middle

Soil Sampling Results - Lower

LNAPL Recovery

0

500

1,000

1,500

2,000

2,500

3,000

0

20

40

60

80

100

120

140

160

180

2008/

31 9/2

9/4

9/6

9/8

9/10

9/12

9/14

9/16

9/18

9/20

9/22

9/24

9/26

9/28

9/30

10/2

10/4

10/6

10/8

10/1

0

10/1

2

10/1

4

10/1

6

10/1

8

10/2

0

10/2

2

10/2

4

10/2

6

10/2

8

10/3

0

11/1

11/3

Cum

ulati

ve R

ecov

ery (

gal)

Daily

Rec

over

y (ga

ls/d

ay)

Oasis SEAR Pilot Study LNAPL RecoveryDaily_tanks (estimated)

Daily_OWS

Cum_OWS

Cum_totalTr

acer

inje

ction

Surf

acta

nt-fl

ush

star

ted

Pre-

flush

star

ted

Post

-flus

h st

arte

d

2-hr

Pow

er o

utag

e

Vacu

umap

plie

d

Sys d

own

to re

adju

st EX

-01

13-h

r pow

erou

tage

Note:Vacuum truck events done on9, 14, 20, 21, 27 Oct, and 9 Nov 09

New

confi

gura

tion

Sysd

own

from

5 am

1

Nov

tp 4

pm

2 N

ov

for G

W sa

mpl

ing

End

of P

ost-

flush

(PV5

)

Extraction Well - Partial Plugging

Key Findings

• Motivation for full-scale implementation– Significant LNAPL removal - 2,740 gal – Significant reduction in LNAPL thickness– Significant reduction in soil TPH-DRO – Hydraulic control achieved and maintained– No increase in dissolved-phase concentrations– Optimized surfactant formulation

Key Findings

• Lessons learned as a result of the pilot study– Heterogeneous NAPL thickness along perimeter– Heterogeneous stratigraphy – Mobilization of fine sand– Emulsification within process equipment

• Fixes– Better placement of well screens– Improved well locations– Improved surfactant formulation– Longer residence times in oil/water separator

Full Scale Implementation

Final review with State Regulatory Agency, Military Base Final review with State Regulatory Agency, Military Base Groups on November 12Groups on November 12thth

Decision for full scale (3.6 acres) made - RFP issuedDecision for full scale (3.6 acres) made - RFP issued Implementing in 3 parcels of 1.2 acres eachImplementing in 3 parcels of 1.2 acres each System installation in May 2010System installation in May 2010 Surfactant injection in June 2010Surfactant injection in June 2010 Post surfactant flush to be finished November 2010Post surfactant flush to be finished November 2010