SOURC
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CE REPORT B:
FINAL
F
REPOR
R
RT FOR PULSE
ED OXY
YGEN
BIOSPA
B
ARGING
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BS) PILO
OT TES
ST
Is
ssued: Octob
ber 2015
Prepared by:
The LA LNAPL Workgroup
p
FINAL
F
REPOR
R
RT FOR PULSE
ED OXY
YGEN
BIOSPA
B
ARGING
G (POB
BS) PILO
OT TES
ST
ssued: Octob
ber 2015
Is
Prepared
P
by:
The
T LA LNAP
PL Workgrou
up
AE
ECOM
999
9 Town and Cou
untry Rd., Orang
ge, CA 92868
tel. 714.567.2430
GS
SI Environmental Inc
c.
2211 Norfolk, Suite
e 1000, Houston, Texas 77098-4
4054
tel. 713.522.6300
October 2015
COMMENTS ABOUT THIS DOCUMENT?
Submit any comments or suggestions directly to:
Mr. Mike Wang
Western States Petroleum Association
970 W. 190th Street, Suite 770
Torrance, CA 90502
(310) 324-8565
TO CITE THIS DOCUMENT:
Los Angeles LNAPL Working Group, 2015. Final Report for Pulsed Oxygen Biosparging (POBS)
Pilot Test. Western States Petroleum Association, Torrance, California.
AUTHORS
Charles Newell, Michal Rysz, Poonam Kulkarni, Rebecca Buthe, Brian Strasters, Kate Hamel, GSI
Environmental Inc.
Matt Himmelstein and Roy Patterson, AECOM
LA LNAPL Workgroup
Pulsed Oxygen Biosparge Pilot Test
October 2015
FINAL REPORT FOR PULSED OXYGEN BIOSPARGING (POBS)
PILOT TEST
Table of Contents
1.0
EXECUTIVE SUMMARY
1
1.1
1.2
1.3
1.5
PILOT TEST OBJECTIVES (SECTION 2.0)
PILOT TEST DESIGN (SECTION 3.0)
PILOT TEST OPERATION (SECTION 4.0)
PILOT TEST PERFORMANCE SUMMARY (SECTION 6.0)
1
1
2
5
2.0
PILOT TEST OBJECTIVES
1
2.1
2.2
2.3
TECHNOLOGY OVERVIEW
APPROACH: PUSH THE TECHNOLOGY
OBJECTIVES AND PERFORMANCE METRICS
1
1
2
3.0
PILOT TEST DESIGN
4
3.1
3.2
3.3
3.3.1
3.3.2
3.3.3
3.3.4
3.3.5
3.3.6
POBS OVERVIEW
PRE-TEST DESIGN ACTIVITIES
POBS TEST DESIGN
GEOLOGY, HYDROGEOLOGY AND LNAPL DISTRIBUTION
BIOSPARGING WELL LAYOUT
WELL DESIGN
KEY DESIGN PARAMETERS
OXYGEN DELIVERY SYSTEM
PLANNING LEVEL MASS BALANCE ANALYSIS
4
5
6
7
7
7
8
9
10
4.0
PILOT TEST OPERATION
11
4.1
4.2
4.3
4.4
4.5
4.6
4.7
STARTUP PHASE
INCREASED GAS INJECTIONS
FIRST OXYGEN “DAYLIGHTING” EVENT
FURTHER INCREASE IN GAS INJECTIONS
ADDITIONAL DAYLIGHTING, SHORT CIRCUITING EVENTS
VOLUME OXYGEN INJECTED
MECHANICAL EQUIPMENT AND WELLS
11
11
11
12
12
12
12
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Pulsed Oxygen Biosparging Pilot Test
October 2015
5.0
PILOT TEST RESULTS
14
5.1
5.1.1
5.1.2
5.1.3
5.1.4
5.2
5.2.1
5.2.2
5.2.3
5.3
5.3.1
5.3.2
5.3.3
5.3.4
5.3.5
5.3.6
5.4
5.5
5.6
GROUNDWATER MONITORING DATA: DISSOLVED OXYGEN AND ORP
DURING STARTUP
AFTER TWO MONTHS
SEPTEMBER INJECTION TESTS
DISSOLVED OXYGEN DATA TO FEBRUARY 2013
GROUNDWATER MONITORING DATA: DISSOLVED CONSTITUENTS
CONCENTRATION VS. TIME GRAPHS
CONCENTRATION VS. TIME BAR CHARTS
SUMMARY STATISTICS: BEFORE VS. AFTER CONCENTRATIONS FOR GROUNDWATER
SOIL DATA FROM BEFORE- AND AFTER-TEST BORINGS
VISUALIZATION OF SOIL DATA
BEFORE AND AFTER AVERAGE CONCENTRATION
STATISTICALLY SIGNIFICANT DECREASES AND INCREASES
BEFORE-TEST CPT AND UVOST
BEFORE VS. AFTER UVOST, CORE PHOTOGRAPHY, AND SOIL ANALYSIS
BEFORE VS. AFTER CORE PHOTOGRAPHY AND PORE FLUIDS ANALYSIS
MASS BALANCE ANALYSIS WITH INCREASING TPH CONCENTRATIONS
STOICHIOMETRIC ANALYSIS OF OXYGEN INJECTION
KEY QUESTIONS ABOUT THE MASS BALANCE ANALYSIS
14
14
14
14
15
16
16
16
17
20
20
20
22
23
23
24
26
29
30
6.0
PILOT TEST PERFORMANCE SUMMARY
32
6.1
6.2
6.3
6.4
6.5
6.6
6.7
CHANGE IN LNAPL MASS IN TREATMENT ZONES
CHANGE IN APPARENT LNAPL THICKNESS AT WELLS IN TREATMENT ZONES
CHANGE IN CONCENTRATION AND MASS DISCHARGE (MASS FLUX) IN TREATMENT ZONES
CHANGE IN LNAPL MOBILITY
CHANGE IN LNAPL COMPOSITION IN THE TREATMENT ZONES
CONCENTRATIONS OF DO IN THE TREATMENT ZONES
COST OF TREATMENT WHEN APPLIED TO FULL SCALE
32
33
33
33
34
34
34
7.0
REFERENCES
36
LA LNAPL Workgroup
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Pulsed Oxygen Biosparging Pilot Test
October 2015
LIST OF FIGURES
Figure E.1.
Pilot Test Layout
Figure 3.1.
Site Location and Layout
Figure 3.2.
Site NAPL Distribution
Figure 3.3.
Pulsed Oxygen Biosparging (POBS) System Pilot Test Focus Area
Figure 3.4.
Original Design for Biosparge Well Construction and CPT/ROST Characterization
Data
Figure 3.5.
Pilot Test Layout with Biosparge and Monitoring Locations
Figure 3.6
Conceptual POBS System Components
Figure 4.1.
Final Locations of POBS Injection and Monitoring Wells.
Figure 4.2.
Daily Injection Well Volumes for Injection Wells IW-1P (top), IW-2P (middle), and IW3P and IW-3R (bottom) in Units of SCF per day.
Figure 5.1.
Output from Downhole Sensor Over Four Days, Showing Injection Signal in Pressure
and Conductivity, But Problem with DO and ORP sensors.
Figure 5.2.
Dissolved Oxygen and ORP After Two Months of Operation. Only IW-3P Showed
Any Response to the Pulsing.
Figure 5.3.
Dissolved Oxygen Utilization Twelve Hours After Oxygen Pulse In One Injection Well
Figure 5.4.
Dissolved Oxygen in Groundwater: All Injection (Tan color), Monitoring (Green), and
Background (Grey) Wells, June 2012 to February 2013.
Figure 5.5.
Benzene Concentrations in Groundwater vs. Time in All Wells (in µg/L)
Figure 5.6.
BTEX Concentrations in Groundwater vs. Time in All Wells (in µg/L)
Figure 5.7.
TPH Concentrations in Groundwater vs. Time in All Wells (in µg/L)
Figure 5.8.
Benzene in Groundwater: All Injection (Tan color), Monitoring (Green), and
Background (Grey) Wells, June 2012 to August 2013
Figure 5.9.
BTEX in Groundwater: All Injection (Tan color), Monitoring (Green), and Background
(Grey) Wells, June 2012 to August 2013.
Figure 5.10.
TPH (All Fractions) in Groundwater: All Injection (Tan color), Monitoring (Green), and
Background (Grey) Wells, June 2012 to August 2013.
Figure 5.11.
Summary Statistics for Benzene, BTEX, and TPH-All Fractions in Groundwater: All
Injection (Blue color), Monitoring (Green), and Background (Yellow) Wells, June 2012
to August 2013.
Figure 5.12.
Soil Analysis Results for Benzene, BTEX, and TPH (all samples).
Figure 5.13.
Soil Data Posted on Triangle Chart, With Before-Test Concentrations on X-Axis and
After-Test Concentration on Y-Axis.
Figure 5.14.
Cone Penetrometer (CPT) and UV Optical Screening Tool (UVOST) Logs.
Figure 5.15.
Cone Penetrometer (CPT), Before and After UV Optical Screening Tool (UVOST),
and Core Photography for Borings MW-1 and MW-2.
Figure 5.16.
Cone Penetrometer (CPT), Before and After UV Optical Screening Tool (UVOST),
and Core Photography for Borings MW-3 and MW-4.
Figure 5.17.
Before and After Test UV Optical Screening Tool (UVOST), and TPH-All Fractions
Data for Borings MW-1 and MW-2.
LA LNAPL Workgroup
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Pulsed Oxygen Biosparging Pilot Test
October 2015
Figure 5.18.
Before and After Test UV Optical Screening Tool (UVOST), and TPH-All Fractions
Data for Borings MW-3 and MW-4.
Figure 5.19.
Core Photography and TPH Data
Figure 5.20.
Core Photography and Two Before- and After-Test LNAPL Saturation Results
LIST OF TABLES
Table E.1.A
Geometric Means of Before and After Constituent Groundwater
Concentrations for Injection Wells
Table E.1.B
Geometric Means of Before and After Constituent Groundwater
Concentrations for Monitoring Wells Inside Treatment Area
Table E.2.
Arithmetic Average Concentration Before and After Pilot Test
Table 3.1.
LNAPL Saturation and LNAPL Mobility Results from Core Analysis and Summary of
Observed LNAPL Accumulation in Three Shallow and
Two Deep Monitoring Wells.
Table 3.2.
Key Initial Design Parameters for the POBS System Pilot Test
Table 3.3
Example Injection Pressure Parameters for the POBS Pilot Test System
Table 4.1
Actual Injection Pressures with Fracture and Initial Design Pressure
Table 5.1.A
Geometric Means of Before, After, and Rebound Constituent
Groundwater Concentrations for Injection Wells
Table 5.1.B
Geometric Means of Before, After, and Rebound Constituent
Groundwater Concentrations for Monitoring Wells Inside Treatment
Area
Table 5.1.C
Geometric Means of Before, After, and Rebound Constituent
Groundwater Concentrations for Monitoring Wells Outside Treatment
Area
Table 5.2.
Arithmetic and Geometric Averages of Before- and After-Test Soil Data.
Table 5.3.
Before and After Pore Fluids Analysis Data for Shallow Zone
Table 5.4.
LNAPL Mobility Test Results Using the Centrifuge Method
Table 5.5.
Arithmetic Average Concentration Before and After Pilot Test
Table 5.6.
Calculated Changes in Mass of Benzene, BTEX, and TPH Fractions
Table 5.7.
Revised Mass Removal Estimate for Benzene and BTEX
Based on Change in Mass Fraction (assuming increase in TPH was due to sampling
variability)
Table 5.8.
Volatilization Parameters for the BTEX Compounds vs. Percentage Removal
LA LNAPL Workgroup
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Pulsed Oxygen Biosparging Pilot Test
October 2015
1.0
EXECUTIVE SUMMARY
1.1
Pilot Test Objectives (Section 2.0)
This Final Report details the results of a pulsed oxygen biosparging (POBS) pilot test for
remediation of light non-aqueous phase liquid (LNAPL) that was conducted at the Shell
Carson Terminal (Site) in Carson, California from June 2012 to June 2013. The pilot tests
performed as part of the Los Angeles (LA) LNAPL Project tested post-conventional
treatment technologies, which are defined as remedial technologies incorporated into site
remediation after the initial LNAPL removal effort has been completed or the LNAPL has
been determined to have low hydraulic recoverability (i.e., low LNAPL transmissivity). Key
points regarding this Pilot Test are:

The POBS technology sparges high concentration (~90%) oxygen into the treatment
zone, which promotes biodegradation of most soluble organic contaminants, like
benzene and BTEX (benzene, toluene, ethylbenzene, and xylenes), without the need for
a soil vapor extraction system.

This Pilot Test had the overall goal to “push” the technology (see Section 2.2) and test
its ability to overcome difficult and/or novel applications in terms of:

1.2
-
Applying POBS in a difficult hydrogeologic setting of a relatively thin (~5-footthick), potentially discontinuous, lower permeability sand/silty sand unit.
-
Treating submerged LNAPL as opposed to the more common application of
POBS to treat dissolved plumes or even LNAPL plumes encountered at the
water-table surface.
-
Designing the test in a way that an actual large-scale deployment of the POBS
technology would be implemented, with large spacing (30 feet) between injection
wells.
-
Pushing the technology and measuring performance between injection points
(approximately 15 feet away) and not adjacent or close to the injection wells.
The Pilot Test was designed to evaluate changes in mass, composition of LNAPL,
concentrations in groundwater, and mass discharge of the dissolved plume; operational
factors (such as how easy was the technology to implement); and cost (see Section 2.3).
Pilot Test Design (Section 3.0)
A Matrix Environmental Technologies Inc. onsite system was used for oxygen generation,
storage, and delivery. Three injection wells were drilled in the triangular pattern shown in
Figure E.1. Originally, two different transmissive units were targeted for treatment, but the
planned treatment of the deeper unit had to be abandoned due to accumulation of several
feet of LNAPL in the injection wells that would have been challenging to sparge safely with
oxygen. Therefore, the scope of work for drilling the “P2” series of wells in Figure E.1 was
not completed and no sparging or monitoring took place in the P2 zone (see Section 3.0).
LA LNAPL Workgroup
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Pulsed Oxygen Biosparging Pilot Test
October 2015
Figure E.1. Pilot Test Layout. Injection Wells (IW) were spaced 30 feet apart and
Monitoring Wells (MW) were located at four locations within the test zone and two
background locations. The Deeper unit wells (P2) were either not drilled or not used during
the Pilot Test due to the accumulation of LNAPL in the wells.
Note: Injection and monitoring wells are referenced by abbreviated names in this report, such as “IW1P” for well PB-IW-1-P and “MW-1” for well PB-MW-1-P.
1.3
Pilot Test Operation (Section 4.0)
The POBS injection system experienced several operational difficulties during the 12-month
testing period, as follows:

High injection pressures were required to inject the oxygen in the treatment zone,
demonstrating the difficulty of injecting into this type of formation.

The lack of any dissolved oxygen (DO) change in the monitoring wells early in the test
resulted in a decision to inject more oxygen than in the initial design parameters.

The high injection pressures and/or large injection volumes, in turn, resulted in two
daylighting events that required two injection wells to be abandoned. A short circuiting
LA LNAPL Workgroup
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Pulsed Oxygen Biosparging Pilot Test
October 2015
event required one of these abandoned wells, well IW-3P, to be overdrilled and
removed.

In the end, three injection well related drilling events were performed during the test: (1)
drilling of the three original injection wells; (2) drilling of injection well IW-3R to replace
injection well IW-3P, and (3) overdrilling/removal of injection well IW-3P. Additionally,
injection well IW-2P was taken out of service after seven months of biosparging and was
not redrilled.

An approximate total of 38,600 standard cubic feet (SCF) of oxygen were injected during
the test. The longest running injection well with no operational problems (IW-1P) was
able to support an average injection rate of 41 SCF per day during the year-long test.
In general, the mechanical equipment functioned as designed during the test, requiring little
maintenance; however, the relatively thin, heterogeneous formation made it difficult to inject
oxygen in the subsurface.

High DO concentrations were most apparent in the injection wells, and in one monitoring
well where a short-circuiting event through the monitoring well screen was likely
occurring. After about four months, small but statistically significant increases in DO (0.5
to 3 mg/L) were observed in the three working monitoring wells and (unexpectedly) in
both background wells. The pattern of these increases suggests that after a year, the
biosparging system was delivering low volumes of oxygen to the relatively large area
represented by these wells.

Over 90% of the dissolved phase benzene and BTEX compounds were removed from
the high-oxygen zone around the injection wells (Table 5.1.A), with lower removals for
TPH (~30%) which is consistent with the aerobic biodegradation process. Lower oxygen
levels at the monitoring wells located away from the injection wells likely caused lower
removals of benzene (40%) and toluene (45%) and some removal of xylenes (19%) and
ethylbenzene (9%) (Table 5.1.B; overall reduction).

The groundwater data were found to be log-normally distributed rendering the geometric
mean concentration values meaningful for comparison.
Rebound testing was conducted sixteen months after system shutdown and
concentrations were compared to “After” concentrations at the wells. Some rebound
occurred in the injection wells. Rebound did not affect the overall reduction in
concentrations at these locations, and the overall reduction percentages were similar
compared to the “Before” vs. “After” difference.

LA LNAPL Workgroup
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Pulsed Oxygen Biosparging Pilot Test
October 2015
Table E.1.A Geometric Means of Before and After Constituent
Groundwater Concentrations for Injection Wells
Before
Concentration
(µg/L)
Benzene
BTEX
TPH – All Fractions
795
2,737
46,659
After
Concentration
(µg/L)
16
154
32,061
Percent
Reduction
98%
94%
31%
Table E.1.B Geometric Means of Before and After Constituent Groundwater Concentrations for
Monitoring Wells Inside Treatment Area
Before
After
Concentration
Concentration
Percent
(µg/L)
(µg/L)
Reduction
Benzene
BTEX
TPH - All Fractions
883
2,625
54,919
638
2,124
34,269
28%
19%
38%

Benzene concentrations in soil decreased slightly after the test (11% reduction using an
arithmetic average). BTEX was unchanged (Table E.2).

The mass fraction of both benzene and BTEX decreased by about 51% and 45%
respectively during the test, which is statistically significant at the p=0.05 level.
However, the majority of the reduction was due to toluene and benzene with no change
in concentration of xylene or ethylbenzene This confirms that a significant composition
change (removal of benzene and BTEX) did occur during the year-long test.
The average concentration of the TPH-All Fractions increased by 82% before and after
the test. This increase in TPH has two likely potential explanations: 1) an LNAPL inflow
during the test, potentially due to the surging action of the oxygen pulses; and/or 2)
random sampling variability. The Ultraviolet Optical Screening Tool (UVOST) and core
photography data do not indicate LNAPL inflow (Figures 5.17 to 5.19).

LA LNAPL Workgroup
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Pulsed Oxygen Biosparging Pilot Test
October 2015
Table E.2. Arithmetic Average Concentration Before and After Pilot Test
Benzene
(mg/kg)
BTEX
(mg/kg)
TPH - ALL
(mg/kg)
GRO
(mg/kg)
DRO
(mg/kg)
Pre-Test
Post-Test
% Reduction
9.1
8.1
11%
86
86
0%
5,151
9,361
-82%
2,600
4,722
-82%
2,481
4,536
-83%
Statistically
Significant?
Yes
No
No
No
No
Notes: Negative % Reduction indicates an increase in average concentrations.
GRO = Gasoline Range Organics, DRO = Diesel Range Organics

Only two pairs of before and after LNAPL saturation data were available for analysis.
These two pairs of LNAPL saturation data for MW-1 and MW-2 (Figure 5.20) either
decreased or stayed the same (12.3% to 5.5% and 7.7% to 7.6%). The before and after
soil samples generally showed an increase in TPH concentration (Figure 5.17 and 5.19);
the reason for this trend is unknown. Insufficient LNAPL data collection and the
heterogeneity of the soil analysis prevent any statistically significant conclusions.


Benzene removed: between 3.6 – 6.5 kilograms (51% removal)
BTEX removed: between 30 - 55 kilograms (45% removal), equivalent to 170 to 310
gallons of pure BTEX per year from a five-foot saturated interval. The Natural Source
Zeon Depletion Test (NSZD) at the Shell facility measured 1700 gallons of LNAPL
degraded per acre per year, but was measuring the degradation of many LNAPL
components in the entire soil column.

A mass balance estimate suggests that 1.9% to 10.6% of the oxygen delivered to the
treatment zone was consumed for biodegradation of BTEX.

Our analysis detailed in Section 5.6 suggests that there is no evidence of LNAPL inflow,
losses attributable to volatilization were not significant, and the soil sampling data
accurately show a reduction in the mass fraction of benzene and BTEX during the test.
1.5
Pilot Test Performance Summary (Section 6.0)
Overall the key Pilot Test results are:

It was difficult to inject into the thin, heterogeneous unit, and several daylighting
events (oxygen channels emerging at the surface) made operation of the biosparge
system difficult during the year-long test. Units where LNAPL is present and can
accumulate in the injection wells may be difficult or impossible to biosparge like the
deep wells in the Pilot Test. Submerged NAPL makes the applicability of this
technology difficult to assess prior to drilling.
LA LNAPL Workgroup
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Pulsed Oxygen Biosparging Pilot Test
October 2015

The mass fractions of benzene and BTEX in soil were reduced by 51% and 45%
respectively during the year-long test, a statistically significant change. This confirms
that the expected composition change* (preferential removal of BTEX compounds as
opposed to removal of LNAPL mass) was established by the oxygen biosparge
system during the test. It would likely take several more years of biosparging to
reduce the benzene and BTEX mass fractions by 90%.
* The ITRC LNAPL Framework document (ITRC, 2009) also uses the term “LNAPL Phase Change”
as well as composition change. LNAPL Phase Change is defined as “Reliance on or application of
a technology that indirectly remediates the LNAPL body via recovery and/or in situ
destruction/degradation of vapor or dissolved-phase LNAPL constituents.”
LA LNAPL Workgroup
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Pulsed Oxygen Biosparging Pilot Test
October 2015
2.0
PILOT TEST OBJECTIVES
2.1
Technology Overview
This Final Report details the results of a POBS pilot test for remediation of LNAPL that was
conducted at the Shell Carson Terminal (Site) in Carson, California from June 2012 to June
2013. All the pilot tests performed as part of the Los Angeles (LA) LNAPL Project tested
post-conventional treatment technologies, which are defined as remedial technologies
incorporated into site remediation after the initial LNAPL removal effort has been completed
or the LNAPL has been determined to have low hydraulic recoverability (i.e., low LNAPL
transmissivity).
The oxygen biosparging remediation method can refer to a variety of different oxygen
delivery approaches, such as:




Low flow rate, continuous addition of air;
Low flow rate, continuous addition of high concentration (~90%) oxygen;
High flow rate, but limited duration (pulsed) sparging of air; and
High flow rate, but limited duration (pulsed) sparging of high concentration oxygen.
The technology identified for pilot testing at the Site was the last delivery approach: high
flow rate pulsed sparging of high concentration (~90%) oxygen. By using a high flow
rate, the zone of airflow (or zone of influence [ZOI]) for biosparging can approach the zone
of airflow that is experienced during conventional air sparging, while minimizing the phase
transfer (volatilization) of volatile organic compounds (VOCs) that occurs with constant air
injection. Biosparging in this manner is intended to promote the degradation of
hydrocarbons by increasing the activity of naturally occurring microorganisms.
This technology has several different names, including Oxygen Pulse Injection System
(OPIS) (Shell Global Solutions, 2007).
2.2
Approach: Push the Technology
This Pilot Test had the overall goal to “push” an existing remediation technology, POBS, and
test its ability to overcome difficult and/or novel applications in terms of the hydrogeological
setting, source location, injection well spacing, and performance monitoring of the system,
as described below:

Apply POBS in a difficult hydrogeologic setting of a relatively thin (~5-foot-thick),
potentially discontinuous, lower permeability sand/silty sand unit. In the LA LNAPL
Literature Review document (LA LNAPL Workgroup, 2011) this type of hydrogeologic
setting was defined as a “Type III – Granular Media with Moderate to High
Heterogeneity.” This type of setting is different than the typical larger, thicker sand
units in which many sparging systems are installed.

Determine the ability of the POBS technology to treat submerged LNAPL as
opposed to the more common application of POBS to treat dissolved plumes or even
LA LNAPL Workgroup
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Pulsed Oxygen Biosparging Pilot Test
October 2015
water-table LNAPL. Submerged LNAPL is defined as “LNAPL that is found well
below the water table due to a historical release, followed by a rising water table.
Most submerged LNAPL is in the residual form, and conventional floating LNAPL
conceptual models do not apply. Submerged LNAPL is found in the LA Basin at
sites with older, historical releases of LNAPL due to rising water table since the
1950s” (LA LNAPL Workgroup, 2007). At this site, the submerged LNAPL in the
treatment zone was located approximately 24 feet below ground surface and 17 feet
below the water table. A successful project that employed “deep air sparging”
(Klinchuch et al., 2007) provided some support for applying POBS to deeper units.

Design the test in a way that an actual large-scale deployment of the POBS
technology could be evaluated with large spacing (30 feet) between injection wells.
For example, guidance developed by Shell suggested wells on 5-foot centers for
barrier designs and wells on 10-foot centers for areal treatments (Shell Global
Solutions, 2007). This spacing would not be practical for large treatment areas (tens
or even hundreds of acres) of treatment zone containing submerged LNAPL. For
this test, 30-foot spacing between injection wells was used. Again, the deep air
sparging project by Klinchuch et al., (2007) indicated that larger spacings could be
successful, but in a different hydrogeologic setting.

Push the technology and measure performance between injection points
(approximately 15 feet away) and not adjacent or close to the injection wells. The
goal was to determine the ability of the POBS system to distribute the oxygen, and
therefore the zone of biodegradation, throughout the treatment zone.
If the POBS system was successful at meeting these four challenges, then the POBS
technology could provide a potential method to treat relatively large areas of submerged
LNAPL in Type III heterogeneous formations, after issues such as safety, access, cost, and
performance are evaluated.
2.3
Objectives and Performance Metrics
The objective of the Pilot Test was to evaluate whether oxygen biosparging is a viable
option for remediation of residual LNAPL, and to estimate optimal operating parameters and
system requirements identified during a prior engineering evaluation performed to identify
potentially feasible technologies for remediation of LNAPL. The success of the technology
was evaluated in terms of technical feasibility and cost effectiveness. Performance metrics
that were considered for technology assessment include:




Change in LNAPL mass in treatment zones;
Change in apparent LNAPL thickness at wells in treatment zones;
Change in mass discharge (mass flux) from treatment zones;
Change in LNAPL mobility;
LA LNAPL Workgroup
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Pulsed Oxygen Biosparging Pilot Test
October 2015





Change in LNAPL composition in treatment zones;
Change in benzene concentrations in treatment zones;
Concentrations of dissolved oxygen (DO) and carbon dioxide (CO2) and oxidationreduction potential (ORP) in treatment zones;
Cost of treatment when applied to full scale operation; and
Selected sustainability metrics (energy use, carbon footprint).
RESULTS: Pilot Test Objectives



The POBS technology sparges high concentration (~90%) oxygen into the treatment
zone, which promotes biodegradation of most soluble organic contaminants, like
benzene and BTEX, without the need for a soil vapor extraction system.
The Pilot Test had the overall goal to “push” the technology and test its ability to
overcome difficult and/or novel applications in terms of the hydrogeological setting,
source location, injection well spacing, and performance monitoring of the system
The Pilot Test was designed to evaluate changes in mass, composition of LNAPL,
concentrations in groundwater, and mass discharge of the dissolved plume; operational
factors (such as how easy was the technology to implement); and cost.
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3.0
PILOT TEST DESIGN
The Site is located in Carson, California (Figure 3.1). The conditions at the Site have been
thoroughly delineated and documented during previous assessments and remediation
activities. Recent reports that document Site conditions include the Light Non-Aqueous
Phase Liquid (LNAPL) Recovery Pilot Test and Recovery Modeling Report (Geosyntec,
2008a), Supplemental Light Non-Aqueous Phase Liquid (LNAPL) Recovery Pilot Test and
Recovery Modeling Report (Geosyntec, 2008b), Light Non-Aqueous Phase Liquid (LNAPL)
Investigation (Geosyntec and URS, 2007), and the Site Assessment Report, Former
Process Area (Brown and Caldwell, 2007). Details of the conditions pertinent to this work
plan are provided below.
The Site-wide LNAPL distribution, as characterized in 2007 and 2008, is shown on Figure
3.2. In figure 3.2, “Heavy, Drowned HC” represents a submerged heavier petroleum
hydrocarbon LNAPL. Cone penetrometer test/rapid optical screening tool (CPT/ROST)
characterization data from location PA11 (Figure 3.3) have indicated that the bulk of the
LNAPL within the Pilot Test focus area is encountered in two intervals located between
approximately 23 and 25 feet below ground surface (ft bgs) and 43 and 47 ft bgs. LNAPL
pore fluid saturations, estimated from nearby Area 6 characterization data, ranged from nondetect (<0.1%) to 12.9%. The potentially biodegradable fraction of the LNAPL (11%) was
estimated based on soil concentrations of volatile and semi-volatile constituents in samples
collected in the vicinity of location PA11. These laboratory results were obtained from
previous site characterization reports (Geosyntec and URS, 2007; Geosyntec, 2008a).
The POBS technology is a “composition change technology” (see note on page E-5
about “phase change” vs. “composition change” terminology) that allows treatment of
aerobically biodegradable LNAPL fractions within the treatment zone. Treatment was
targeted at constituents dissolved in groundwater and present within the LNAPL. Because
the soluble/biodegradable fraction was characterized as relatively small, POBS was not
expected to reduce overall LNAPL mass significantly.
3.1
POBS Overview
The initial design variables for the Pilot Test were an injection volume necessary to occupy
10% pore volume per week (based on Leeson et al., 2002); pulsed sparge events at flow
rates of approximately 15 to 20 standard cubic feet per minute (SCFM) (based on Leeson et
al., 2002); and oxygen injection rates greater than 15 SCFM (Shell Global Solutions, 2007).
These design variables were changed following system start-up based on the response of
the subsurface to oxygen injection.
The Pilot Test design consisted of three oxygen biosparging injection wells installed in a
triangular pattern at 30-foot spacing in the vicinity of CPT/ROST location PA11 (Figure 3.3).
Initially, two different zones were planned to be tested: a shallower, thin, less permeable
zone found approximately 8 feet below the general potentiometric surface shown in nearby
monitoring wells (approximately 23 ft bgs) and a thicker, relatively more permeable zone
found approximately 32 ft below the general potentiometric surface (approximately 47 ft bgs)
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(Figure 3.4). However, the significant accumulation of recoverable LNAPL in the first wells
drilled in the deeper zone led to the decision to test only the upper zone.
The injection well spacing for the Pilot Test is 30 feet and was chosen based on the
following rationale:

Bass et al. (2000) evaluated the performance of air sparging at 49 sites, and
reported that the “successful systems” were spaced an average of 28.6 ft apart. The
30-foot spacing chosen for the Pilot Test is close to the average spacing of
successful air sparging projects in the Bass et al. (2000) study.

The presence of confining units in the heterogeneous hydrogeologic setting at the
Site, like other facilities in the LA Basin, is believed to promote lateral movement of
the oxygen (Leeson et al., 2002).

A common default value of 10-foot spacing for oxygen biosparge projects (Shell
Global Solutions, 2007) and 15-foot spacing for air sparging projects (Leeson et al,
2002) would not likely be cost effective for large-scale, wide-spread areal treatment
of residual LNAPL, as somewhere between 200 and 450 wells per acre would be
required. For 30-foot spacing, only 50 wells per acre would be required. Note that
Leeson et al. (2002) allow for pilot tests to establish the “smallest well spacing that is
not cost-prohibitive” and Shell Global Solutions (2007) allows for evaluation of other
well spacings. Because the Western States Petroleum Association – Los Angeles
(WSPA LA) LA LNAPL Project is focused on both cost and performance, the
scalable spacing option (30 ft between wells) was selected for this Pilot Test.

The estimated ZOI from a previous air sparging test conducted at the Site was
reported at 22 feet (URS, 2007). (In theory, injection wells can be spaced at two
times the ZOI; however, in practice the ZOIs of adjacent wells typically overlap to
some degree.)
Oxygen was generated onsite from ambient air with a Matrix Environmental Technologies
Inc. pressure swing adsorption (PSA) oxygen generation system on loan from Shell, which
has been successfully implemented at other sites for the remediation of BTEX and
oxygenate-impacted groundwater. The generated oxygen was stored in a reservoir tank until
delivered to the injection wells. The system is capable of generating approximately 50
standard cubic feet per hour (SCFH) of oxygen.
3.2
Pre-Test Design Activities
In August 2012, two shallow injection wells, two shallow monitoring wells, two deep injection
wells and two deep monitoring wells were drilled. Soon after completion, 21 to 27 feet of
LNAPL accumulation was observed in all four deep wells. After reviewing safety and
operational issues, it was decided to abandon the deeper unit and just perform the Pilot Test
in the shallow unit.
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Curiously, soil samples tested for NAPL fluids information (saturation, mobility) did not
indicate any significant differences between the shallow zone (where there was no LNAPL
accumulation) and the deeper zone (where there was over 20 feet of LNAPL accumulation)
(Table 3.1).
Table 3.1. LNAPL Saturation and LNAPL Mobility Results from Core Analysis and Summary of
Observed LNAPL Accumulation in Three Shallow and
Two Deep Monitoring Wells.
NAPL Pore Fluid Saturations
Location*
Shallow Unit
IW-1P
MW-2P
MW-1P
Deep Unit
MW-2P2
MW-1P2
Well Data
LNAPL
Accumulation
in Unit (feet)
Depth
(ft bgs)
NAPL Saturation (%PV)
Average NAPL
Saturation (%PV)
23.25
23.55
23.15
6.4
7.7
12.3
8.80
0 feet in
Three Wells
43.35
5.8
8.15
21.8 to 27.3
feet in Two
Wells
Fluid Sat. After
Centrifuge 1000xG
(%PV)
Change in
Saturation
(%PV)
42.25
10.5
Free Product Mobility
Location
Depth
(ft bgs)
Initial Fluid Sat.
(%PV)
Shallow Unit
MW-1P
23.30
9.5
9.20
Deep Unit
MW-1P2
42.40
10.0
9.60
*Notes: bgs = below ground surface. %PV = percent of pore volume.
-0.3
-0.4
In May 2012, a “pre-test” injection test was performed. Compressed nitrogen from a cylinder
was injected into both wells to evaluate if oxygen could be injected into the formation at
pressures below 45 pounds per square inch gauge (psig). Injection pressures in the shallow
zone were high (16.8 psig required to get 20 SCM nitrogen flowrate) and above the potential
fracture pressure but considered acceptable to continue for reasons discussed in Section
3.3.4.
3.3
POBS Test Design
The area identified for the Pilot Test is located in the central portion of the Former Process
Area of the Site in the vicinity of CPT/ROST location PA11 (Figure 3.3). The location was
chosen after a thorough screening of CPT/ROST characterization data, and evaluation of
specific geologic conditions and LNAPL distribution data. Selection criteria considered
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include the presence of submerged LNAPL (inferred from ROST response and nearby
groundwater depth data), LNAPL occurrence in relatively coarser-grained soils, and a
thickness of affected soils of approximately 4 feet or greater. Of the 368 CPT/ROST records
evaluated, location PA11 was selected from approximately six onsite locations that best
satisfied these criteria.
3.3.1
Geology, Hydrogeology and LNAPL Distribution
The general stratigraphy and subsurface LNAPL distribution, as interpreted from CPT/ROST
data at location PA11, are shown on Figure 3.4. The presence of LNAPL is indicated by the
ROST signature at distinct depths down to approximately 47 ft bgs. Soils in this interval
include sands, silts and clays, with the water table at approximately 16.6 ft bgs.
3.3.2
Biosparging Well Layout
The layout of the Pilot Test and original locations of biosparging and monitoring wells are
shown on Figure 3.5 with final well locations shown on Figure 4.1. The conceptual system
design is shown on Figure 3.6. The biosparge pilot system consisted of one PSA oxygen
generation system supplying oxygen to the three injection wells. Four monitoring locations
within the treatment area, together with one upgradient, one downgradient, and one crossgradient monitoring well pair (Figure 3.5) were installed for the purpose of monthly
groundwater monitoring for VOCs and CO2 and more frequent sampling and DO and ORP
distribution monitoring during the Pilot Test.
3.3.3
Well Design
Biosparge wells were installed at three locations using a hollow-stem auger drill rig. The
original design with both shallow and deep injection wells is shown in Figure 3.4. The
injection wells were spaced 30 ft apart as shown on Figure 3.5. Each biosparge well was
constructed with a 2-inch diameter casing and screen. Consistent with Shell Global
Solutions (2007) Oxygen Pulse Injection System (OPIS) Design and Installation Guidance
Document, each well had:





A 2-foot length of 0.010-slot screen;
A 5-foot length (minimum) sump below the slotted screen;
Sand pack from the bottom of the sump to 1 ft above the screen;
A bentonite seal from the top of sand pack to 1 ft above the water table; and
Bentonite-cement grout from the top of the bentonite seal to the ground surface.
In compliance with Shell’s requirements for subsurface investigations, approximately the top
10 feet of soil was removed using an air knife and then replaced to verify that utilities were
not present at the location. The injections and monitoring wells were screened between 23
and 25 ft bgs in a thin sand within a predominantly fine-grained horizon and targeted the
approximately 5-foot-thick upper treatment zone.
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The current water table level at the site is estimated to be approximately 16.6 feet bgs,
corresponding to injection depths of between 6.4 and 8.4 feet below the water table (upper
well). The oxygen injection points were set at the bottom of the treatment zones.
As shown on Figure 3.5, the study area included a total of seven locations for groundwater
monitoring, including four locations within the treatment area, one upgradient location, one
downgradient location, and one cross-gradient pair. Each of the four monitoring locations
within the treatment area included a well with a 4-inch diameter well screen and casing. This
well diameter allowed monitoring of DO and ORP using a downhole optical DO meter.
3.3.4 Key Design Parameters
Key design parameters for the Pilot Test are summarized in Table 3.2. The values listed for
these parameters represent planning-level estimates that were used during the startup
phase of the Pilot Test.
Table 3.2. Key Initial Design Parameters for the POBS System Pilot Test taken from POBS Work
Plan (LA LNAPL 2010).
Parameter
Sparge well spacing
Design zone of oxygen
influence (ZOI)
Injection depth
Value
30 ft
15 ft
23 to 25 ft bgs (Upper wells)
Initial oxygen volume delivered
to formation per week
Oxygen volume delivered per
well per week
10% of pore volume in
treatment zone
106 SCF (Upper Wells)
Oxygen volume delivered per
well per day
15.1 SCF (Upper Wells)
Injection flow rates
15 to 20 SCFM
Injections per day per well
~1 (Upper wells)
Calculated fracture pressures
(Pfracture)
16.8 psig (Upper wells)
Injection duration
~1 minute per injection
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Basis
See Section 3.2
From well spacing; see
URS/GSI 2010.
Site stratigraphy and ROST
data in vicinity of Pilot Test
location
Derived from oxygen demand
data in Leeson et al. (2002)
Pressure corrected injection
volumes
Daily injections necessary to
deliver oxygen volume
equivalent to 10% weekly
saturation
USACE (2008); NFESC (2001);
Leeson et al. (2002); Shell
Global Solutions (2007)
Starting design parameter from
Shell experience; 60-gallon
oxygen storage tank
GSI and AECOM; based on
injection depths
Injection flow rates and
injection volumes
Pulsed Oxygen Biosparging Pilot Test
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Injection Pressure
In general, guidance documents indicate that the fracture pressure should not be exceeded
during sparging system operation due to formation fracturing in the immediate vicinity of the
injection wells (NFESC 2001; Leeson et al., 2002; USACE 2008). The initial injection
pressures calculated for the startup phase (with a 30% safety factor, SF) are shown in Table
3.3. However field experience from sparging systems indicates that to induce gas flow and
achieve flow rates greater than 10 SCFM it may be necessary to exceed the calculated
fracture pressures (personal communication with T. Peargin, 2010).
Therefore a
contingency plan was made that if flow is not achieved at Pmax,initial or if oxygen distribution is
not adequate at this pressure, the injection pressures would be increased incrementally until
satisfactory oxygen profiles are established.
Table 3.3 Example Injection Pressure Parameters for the POBS System Pilot Test
Sparge Well
Injection Depth(1)
(ft bgs)
Pmin (psig)
Upper
23
2.75
(1) Depth to top of injection screen (feet below ground surface)
Pfracture (psig)
16.8
Pmax-initial (Pfracture
with 30% SF –
psig)
11.8
Flow Rate
Proper gas flow rate is important so that gas distribution is maximized for biodegradation
without causing gas-stripping of constituents. Flow rates during pulsing reported in the
literature for biosparging projects typically range from less than 5 SCFM to approximately 40
SCFM (USACE, 2008). The most relevant biosparging guidance documents recommend a
target flow rate of approximately 20 SCFM for pilot tests (NFESC, 2001; Leeson et al.,
2002). For this test, the design flowrate was established at 15 to 20 SCFM, but with the
understanding that actual flowrates in the field would be controlled by the injection pressure
and the ability of the formation to accept the oxygen.
Sparge Frequency and Duration
The original sparge frequency for the startup phase of the Pilot Test was planned for one
pulse per day for the upper wells. System parameters such as DO, and ORP (measured
daily during Month 1 and monthly afterwards), and groundwater VOC and CO2
concentrations (collected monthly), were used to evaluate system performance. The
Workplan envisioned that the sparging frequency, injection rate, and injection volumes could
be modified based on field measurements.
3.3.5
Oxygen Delivery System
A Matrix Environmental Technologies Inc. onsite system was used for oxygen generation,
storage, and delivery. The system consisted of a trailer housing all essential aboveground
components, including a PSA oxygen generator, a manifold, solenoid valves and pressure
gauges for monitoring each injection line. Additionally, a totalizing flow meter was installed
to monitor the total volume of oxygen injected. To mitigate potential safety risks, a flame
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arrester was installed at each of the injection well heads. The generated oxygen was stored
in a reservoir tank (the tank capacity was increased during the test) and the pulses were
regulated using timer-activated solenoid valves. High-density polyethylene (HDPE) or
Duraplus artery lines were used for oxygen delivery between the oxygen storage tank and
biosparge wells.
3.3.6 Planning Level Mass Balance Analysis
A planning level analysis of the removal of LNAPL VOCs based on the Air Sparging Design
Paradigm (Leeson et al., 2002) and a first order decay rate was conducted to estimate the
expected LNAPL remediation “glide path” envelopes for the treatment. To generate a range
of removal estimates, the first order decay rate (determined from input parameters) was
adjusted by ± 50% during the analysis. Parameters such as LNAPL VOC mass fraction, and
LNAPL density were obtained from previous site investigation reports (Geosyntec, 2007;
Geosyntec 2008). LNAPL saturation was determined during sampling performed by AECOM
(formerly URS) in August 2011. To account for uncertainties inherent to biosparging
systems regarding oxygen distribution, additional oxygen demand and utilization for aerobic
degradation, an oxygen utilization factor of 50% was assumed in the analysis (i.e., one-half
of the total oxygen mass delivered was assumed to be used in biodegradation reactions).
The preliminary estimates of the mass removal during the initial 12 months of the pilot
system operation indicated that for the upper treatment zone:
 Approximately 66% of the initial BTEX mass present in the LNAPL could be
removed, and
 Removal could range between 42% and 80% of the initial BTEX mass.
These estimated removal rates were based on the assumption that about 16,500 SCF of
oxygen would be injected.
RESULTS: Pilot Test Design




Planned treatment of the deeper unit had to be abandoned due to several feet of LNAPL
accumulation in wells that would have been challenging to sparge safely with oxygen.
A field study for gas injection was conducted to evaluate planning estimates against realworld conditions.
A “Glide-Path” was established to evaluate data during the test so that operations
changes could be made if the results were below expectations.
Initial design parameters (Table 3.2) were selected with the understanding that
significant changes might be made during the Pilot Test based on field measurements.
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4.0
PILOT TEST OPERATION
4.1
Startup Phase
During the startup phase, higher injection pressures than the design values of 11.8 psig
were required to introduce oxygen into the treatment zone (Table 4.1):
Table 4.1 Actual Injection Pressures with Fracture and Initial Design Pressure
Injection
Well
IW-1P
IW-2P
IW-3P
Fracture Pressure
(psig)
Design Pressure
(psig)
16.8
11.8
Actual Startup Pressure
(psig)
18-21
28-29
16
Because of the difficulty in delivering gas to the treatment zone, the initial design of one
pulse per day was changed to two ~10 SCF pulses separated by approximately 30 minutes
during the startup phase of the test. This was done to allow the existing PSA oxygen
generator to develop the required volumes and pressure to inject the calculated volumes.
The change provided a theoretical delivery volume of 20 SCF oxygen per well per day
(compared to the initial plan of 15 SCF per well per day).
4.2
Increased Gas Injections
By August 2012, there had been little oxygen measured in the monitoring wells. Therefore,
the Workgroup decided to increase the oxygen delivery to a total of six pulses per day, with
pulse 1 and 2 separated by 30 minutes, then a wait of approximately 8 hours, then pulses 3
and 4 separated by about 30 minutes, then after a wait of approximately 8 hours, pulses 5
and 6 separated by about 30 minutes. Each pulse had a theoretical delivery volume of
about 10 SCF. The arrangement was necessitated by the equipment’s ability to produce
and store pressurized oxygen.
4.3
First Oxygen “Daylighting” Event
In August 2012, approximately 2 months after startup and after gas injections had been
increased, well IW-3P appeared to create “daylighting” of the oxygen pulse. When this well
was operated, technicians observed fluids and dirt escaping from the surface under the chat
cover. Operation of this well was terminated and a replacement well, IW-3R, was drilled and
put into service in December 2012. Because of drilling constraints, and the desire not to
intersect any channels from the treatment zone to the surface that were associated with IW3P daylighting, the IW-3R replacement well was installed approximately 7 feet east of IW-3P
(Figure 4.1, Note: IW-3R = “PB-IW-3PR” in figure). Additionally, the borehole was not
cleared using an air knife, further reducing the potential for near-surface short circuiting. The
area of the site where the POBS was installed has had significant demolition activities over
time and no active structures were expected to be present. Surface geophysics were
conducted to clear the borehole. The Workgroup does not recommend installing wells
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without subsurface clearance at any site where there exists a potential for buried utilities and
other structures.
4.4
Further Increase in Gas Injections
In December 2012, due to perceived poor distribution of oxygen and a design review
meeting by experts from Shell Global Solutions, the Workgroup increased the theoretical
delivery for each of the 6 pulses per day to approximately 30 SCF (180 SCF oxygen per well
per day) after increasing the oxygen reservoir tank size.
In practice, the amount of oxygen going into each well varied considerably over time due to
the dynamics of the injection pressure required to overcome the resistance to gas flow in the
treatment zone. Figure 4.2 shows the estimated daily gas delivery volumes to each of the
injection wells over time.
4.5
Additional Daylighting, Short Circuiting Events
In December 2012, six months after startup, injection well IW-2P daylighted gas and was
taken out of service and not redrilled.
In February 2013, gas from the IW-3R appeared to be short circuiting to the surface around
the abandoned IW-3P. IW-3P was overdrilled in April 2013, allowing two more months of
sparging from well IW-3R.
4.6
Volume Oxygen Injected
Over the course of the test, the three injection wells were able to deliver these volumes of
oxygen:
 15,700 SCF to IW-1P
 9,140 SCF to IW-2P
 13,760 SCF to IW-3P and IW-3R
 38,600 SCF TOTAL from all injection wells
The average daily volume injected (excluding downtime due to daylighting or short
circuiting) were:



4.7
41 SCF/day to IW-1P
44 SCF/day to IW-2P (while in operation)
63 SCF/day to IW-3P and IW-3R
Mechanical Equipment and Wells
In general, the mechanical equipment (controllers, solenoids, oxygen generator, tankage)
worked well during the test, requiring little routine maintenance.
The pulsed operation of the system, coupled with the fine grain size of the formation
resulted in the silting of the injection wells at various times during the test duration. Each
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well was constructed with a 5-foot sump to minimize silt blocking off the well screens, but
this still occurred and silt was removed on several occasions.
RESULTS: Pilot Test Operation







The POBS injection system experienced several operational difficulties during the 12month testing period. In general, the mechanical equipment worked well during the test,
requiring little routine maintenance. But the relatively thin, heterogeneous formation
made it difficult to inject oxygen in the subsurface. The lack of any DO change in the
monitoring wells early in the test resulted in a decision to inject more oxygen than in the
initial design parameters. Injection gas volumes were increased over the initial design
values at the start of the test, and were increased once again in December 2012.
High injection pressures were required to inject the oxygen in the treatment zone,
demonstrating the difficulty of injecting into this type of formation.
The high injection pressures and/or large injection volumes, in turn, resulted in two
daylighting events that required two injection wells to be abandoned. A short circuiting
event required one of these abandoned wells, well IW-3P, to be overdrilled and
removed.
Typical well clearance procedures may result in the creation of short-circuiting pathways.
In the end, three injection well related drilling events were performed during the test: (1)
drilling of the three original injection wells; (2) drilling of injection well IW-3R to replace
injection well IW-3P, and (3) overdrilling/removal of injection well IW-3P. Additionally,
injection well IW-2P was taken out of service after seven months of biosparging and was
not redrilled.
A total of 38,600 SCF of oxygen were injected during the test. The longest running
injection well with no operational problems (IW-1P) was able to support an average
injection rate of 41 SCF per day during the year-long test.
For pulsed sparging in fine grained lenses, silting will likely take place in the injection
wells. Wells should be constructed with an adequate sump and appropriate well screen
and sand pack, and field time should be estimated to check for, and remove silt
accumulation.
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5.0
PILOT TEST RESULTS
5.1
Groundwater Monitoring Data: Dissolved Oxygen and ORP
Considerable resources were devoted to measuring DO and ORP in the injection and
monitoring wells during the first three months after startup. Optical DO probes (In-Situ RDO
Oxygen Sensors) were installed in two wells in an attempt to observe oxygen pulses and the
subsequent decay from biodegradation and other processes.
5.1.1 During Startup
During startup, the pressure, temperature and conductivity measurements from the In-Situ
probes were successful at detecting the oxygen pulses. However, the ORP and DO data
produce suspect results. For example, Figure 5.1 shows the flatline response of the
dissolved oxygen and ORP sensors compared to the sawtooth pattern of pressure and
conductivity during four days in July in one well. After consulting with the manufacturer it
was determined that LNAPL could coat the sensor and disable the DO and ORP signals. It
is possible that DO saturation did not increase in this well, and it is possible that small
volumes of LNAPL coated and degraded the sensitivity of the instrument.
5.1.2 After Two Months
DO readings using conventional surface field instruments were able to show the DO and
ORP distribution in the injection and monitoring wells during groundwater sampling events.
As shown in Figure 5.2, after two months of operation (August 2012), elevated DO was
observed in injection well IW-3P, where DO had increased from 0.1 mg/L prior to start up to
6.9 mg/L. Very low DO was measured at all the other wells, however.
5.1.3 September Injection Tests
In September 2012, Dr. Cristin Bruce, a pulsed oxygen biosparge expert from Shell, worked
with the AECOM field team to evaluate the performance of the pulsing system. An optical
DO sensor was carefully installed in injection well IW-1P and the well was sealed to allow for
injections. The purpose of the test was to evaluate if oxygen was being transferred to the
groundwater, and if it was persistent in the groundwater following the injection.
Analysis of the data indicated that the water column was being forced from the well and
oxygenated in at least the immediate vicinity of the well. A spike in DO concentrations
following the injection, as groundwater reentered the well, showed that DO concentrations
reached the expected level of saturation, 33 mg/L (Figure 5.3). Then, over the next twelve
hours, the oxygen readings from the probe dropped consistently to 3 mg/L. The results from
this test are consistent with oxygen being delivered to the subsurface (although potentially
just around the injection well) and then being consumed by biodegradation processes
(however no other data are available to confirm this conclusion). The results of this test
indicated that oxygen distribution may be limited and that the high oxygen demand from the
submerged LNAPL may be limiting the ability of oxygen to reach the monitoring points.
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5.1.4 Dissolved Oxygen Data to February 2013
DO data were collected using surface DO meters at each well approximately weekly from
the beginning of the test in June 2012 to February 2013, approximately four months before
the test ended (Figure 5.4). These data did show DO increases in the injection wells, then
declines as two of the wells (IW-2P and IW-3P) were taken out of service due to daylighting
and short circuiting, respectively.
Monitoring wells MW-1, MW-2, and MW-3 showed small but statistically significant increases
in DO over the 12-month test. The highest concentrations were less than 3 mg/L, indicating
some oxygen was being delivered to these wells but that it was likely being removed rapidly
by biodegradation. No dissolved phase monitoring of well MW-4 was performed due the
presence of LNAPL in the well.
Interestingly, DO concentrations in the two background wells increased in the same pattern
as the three monitoring wells: < 0.5 mg/L before the test, then slowly rising over the year
test to the 1 to 3 mg/L level. This indicates that trace amounts of DO from the sparging
system was reaching these wells which were originally envisioned as background wells.
Monitoring well MW-2 showed a rapid increase in concentration in month 7, then a decrease
back to low levels (between 1 and 2 mg/L). During this period injection well IW-3R began to
short circuit to the original IW-3P, which had been taken out of service due to daylighting.
Monitoring well MW-2 is located near IW-3R and IW-3P (Figure 4.1), which may explain the
high DO concentrations observed in MW-2 during the short-circuiting event.
One issue with the periodic DO readings is that these readings were not collected at the
same time each day, relative to the injection period. Therefore, some readings were
indicative of DO concentrations immediately after a pulse, while some were indicative of
conditions after any spike of DO would have been consumed. These readings, on average,
indicate trends in DO readings, but the use of downhole DO monitors (absent interference
from LNAPL) are capable of providing a more sophisticated snapshot of the DO trends.
RESULTS: Dissolved Oxygen, ORP, and Other Field Parameters


High DO concentrations were most apparent in the injection wells, and in one monitoring
well where a short-circuiting event through the monitoring well screen was likely
occurring. After about four months, small but statistically significant increases in DO (0.5
to 3 mg/L) were observed in the three working monitoring wells and in both background
wells. The pattern of these increases suggest that the biosparging system was
delivering oxygen to the areas monitored by these wells.
Optical DO sensors did not perform well in the startup phase. After conferring with the
manufacturing, the presence of small amounts of LNAPL may have compromised the
results. In a subsequent injection test conducted by a Shell POBS expert and the
AECOM field team, the optical DO probes worked well in one test, but not in a second
test in another well. Caution should be exercised if deploying optical DO sensors in
wells with the potential for LNAPL presence.
LA LNAPL Workgroup
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Pulsed Oxygen Biosparging Pilot Test
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5.2
Groundwater Monitoring Data: Dissolved Constituents
5.2.1 Concentration vs. Time Graphs
During the 12-month testing period, reductions in benzene and BTEX concentrations were
observed in groundwater, and remained low sixteen months after the system shutdown
(Figures 5.5 and 5.6). Smaller reductions were observed for TPH-All Fractions (sum of
Gasoline Range, Diesel Range, and Motor Oil Range) (Figure 5.7). In injection well IW-1P,
which had the least operational problems, benzene concentrations were reduced by over
two orders of magnitude, with the final concentration of 5 µg/L maintained for sixteen
months after shutdown. The monitoring wells (circle symbols in Figures 5.5 through 5.7)
showed much less reduction than the injection wells (triangle symbols).
The TPH-All Fractions data showed a more muted response, with a very slow downward
slope of concentrations on Figure 5.7. This is consistent with the original conceptual model
for the POBS process, which targets composition change of the lighter components, such as
the BTEX compounds, compared to the heavier compounds measured in the TPH analyses.
Rebound testing was conducted 16 months after the post-test sampling event and is shown
in Figures 5.5 – 5.7.
5.2.2 Concentration vs. Time Bar Charts
The detailed temporal concentration vs. time records for every well is shown for Benzene
(Figure 5.8), combined BTEX (Figure 5.9), and TPH-All Fractions (Figure 5.10). The
detailed figures show the impact of operational changes on the individual wells at specific
times. For example, reviewing these figures show:





Injection well IW-1P had the highest reduction of any well for benzene and BTEX.
This well had no operational problems during the test and delivered the most oxygen
(15,700 SCF) and had the lowest initial benzene and BTEX concentrations of the
three injection wells.
Benzene and BTEX concentrations increased in Injection well IW-2P after it had to
be shut down in month 7 (January 2013).
High DO in MW-2 from the short-circuiting event resulted in a temporary
anomalously low concentration of benzene and BTEX in month 8.5;
Relatively little change in the background wells for benzene, BTEX, and TPH;
Less fluctuation and little apparent change in the TPH-All Fractions data.
Figure 5.11 shows the geometric means of the injection wells, monitoring wells, and
background wells over time for benzene, BTEX, and TPH-All Fractions. The geometric
means in this figure are for all the wells available for each specific sampling event, leading
to the use of different number of wells for the different time periods if a well was not sampled
LA LNAPL Workgroup
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Pulsed Oxygen Biosparging Pilot Test
October 2015
(due to the presence of LNAPL, for example) or if a well was abandoned (IW-3P). Therefore
a different analysis using the same before- and after-test wells were used for the
comparison in Table 5.1, as discussed in Section 5.2.3. Note the Post Test bars (far right in
Figure 5.11) were taken two months after shutdown, and the rebound testing was taken
sixteen months after shutdown.
The injection wells show a dramatic reduction in benzene and BTEX concentrations over
time, even sixteen months after the test was halted (i.e., rebound testing). TPH-All Fractions
concentrations in the injection wells decreased somewhat, but fluctuated during the test with
a significant rebound observed during post-test sampling and rebound testing. The
background wells fluctuated over time, with two wells (MW-5 and MW-6) showing what
appears to be rebound after the test (even though these wells were located relatively far
away from the injection wells).
5.2.3 Summary Statistics: Before vs. After Concentrations for Groundwater
Geometric means of Before Test (two months before test), After Test (last sample taken
ranging from month 8.5 – 14), and Rebound Testing (month 30) were calculated and shown
in Table 5.1. Additionally, a Test Percent Reduction was calculated using Before vs. After
data, and an Overall Reduction was calculated using Rebound vs. Before data. For this
analysis MW-7 was not used because After Test data were not available.
Table 5.1.A Geometric Means of Before, After, and Rebound Constituent Groundwater
Concentrations for Injection Wells
Benzene
Toluene
BTEX
Ethylbenzene
Total Xylenes
DIPE
GRO
TPH All Fract.
DRO
TPH Motor
Before
(µg/L)
795
674
2,737
102
809
287
11,899
46,659
26,543
4,076
GEOMEAN CONCENTRATIONS
INJECTION WELLS (µg/L)
Rebound
After
Test %
(µg/L)
(µg/L)
Reduction
16
98%
42
22
97%
14
154
94%
163
9
92%
9
100
88%
92
67
77%
71
3,142
74%
3,409
32,061
31%
45,817
19,952
25%
34,192
5,536
-36%
45,817
Rebound
vs. After
155%
-35%
6%
4%
-8%
6%
8%
43%
71%
43%
Overall
Reduction
95%
98%
94%
91%
89%
75%
71%
2%
-29%
-89%
Notes: i) Before data from IW-1P, IW-2P and IW-3P used; ii) latest recorded values used for "After"
and “Rebound” concentrations if unavailable; iii) Positive rebound percentage indicates increase in
concentration compared to “After” value, while negative value shows decrease.
LA LNAPL Workgroup
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Table 5.1.B Geometric Means of Before, After, and Rebound Constituent Groundwater
Concentrations for Monitoring Wells Inside Treatment Area
GEOMEAN CONCENTRATIONS
MONITORING WELLS INSIDE TREATMENT AREA (µg/L)
Before
After
Test %
Rebound
Rebound
(µg/L)
(µg/L)
(µg/L)
Reduction
vs. After
36,133
17,609
51%
18,293
7%
345
169
51%
153
-10%
7,079
3,471
51%
4,818
39%
47,111
24,310
48%
26,497
9%
471
261
45%
240
-8%
370
223
40%
334
50%
1,388
934
33%
1,054
13%
445
359
19%
391
9%
3,229
3,095
4%
2,659
-14%
89
81
9%
25
-69%
DRO
DIPE
GRO
TPH All Fract.
Toluene
Benzene
BTEX
Total Xylenes
TPH Motor
Ethylbenzene
Overall
Reduction
48%
56%
32%
44%
49%
10%
24%
12%
18%
72%
Notes: i) Before data from MW-1, MW-2, MW-3 and MW-4 used; ii) latest recorded values used for
"After" and “Rebound” concentrations if unavailable; iii) Positive rebound percentage indicates
increase in concentration compared to “After” value, while negative value shows decrease.
Table 5.1.C Geometric Means of Before, After, and Rebound Constituent
Groundwater Concentrations for Monitoring Wells Outside Treatment Area
Total Xylenes
DRO
TPH All Fract.
GRO
TPH Motor
Benzene
Toluene
DIPE
BTEX
Ethylbenzene
GEOMEAN CONCENTRATIONS
MONITORING WELLS OUTSIDE TREATMENT AREA (µg/L)
Rebound
Before
After
Test %
Testing
Rebound
(µg/L)
(µg/L)
(µg/L)
Reduction
Percent
473
343
28%
335
-2%
19,975
14,704
26%
16,125
10%
33,411
25,097
25%
25,155
0%
8,139
6,989
14%
5,821
-17%
2,774
2,700
3%
2,627
-3%
643
655
-2%
574
-12%
266
273
-3%
240
-12%
57
59
-4%
43
-26%
1,542
1,671
-8%
1387
-17%
57
187
-227%
112
-40%
Overall
Reduction
29%
19%
25%
28%
5%
11%
10%
24%
10%
-96%
Notes: i) Before and after data for MW-5 and MW-6 used ii) Positive rebound percentage indicates
increase in concentration compared to “After” value, while negative value shows decrease.
The groundwater data were found to be log-normally distributed rendering the geometric
mean concentration values meaningful for comparison. The injection wells exhibited the
expected percentage reduction versus chemical or chemical class in the before- and aftertest results. Benzene had the highest percent reduction (98%), followed by toluene, BTEX
LA LNAPL Workgroup
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Pulsed Oxygen Biosparging Pilot Test
October 2015
and ethylbenzene in the injection wells. These results are consistent with the conceptual
model as the aromatic compounds are seen to have degraded more readily than TPH.
These data also show the high dissolved oxygen concentrations near the injection wells
stimulated aerobic and intense biodegradation process that removed over 90% of the
dissolved constituents. Rebound testing of the injection wells showed an increase in
concentration of benzene (155%) compared to “After” concentration (from 16 µg/L to 42
µg/L). Rebound also occurred for DRO (71%), and TPH (43%). Average rebound
percentage of all constituents in the injection wells was 29%, indicating some rebound in the
injection wells. However, the overall percent reduction, taking rebound into account,
remained high (71% to 98%) for all constituents except for TPH (All Frac. and motor) and
DRO.
The data for the monitoring wells within the treatment area have a different relationship than
the injection well data, however. The TPH showed a greater reduction than the aromatic
BTEX; the reason for this result is unknown. Among the BTEX compounds, only benzene
and toluene were removed. The much lower dissolved oxygen concentrations at the
monitoring wells were likely responsible for the much lower and more selective removals of
hydrocarbon constituents from the dissolved phase (only 28% to 38% of the benzene,
toluene, and TPH was removed). Rebound testing in the monitoring wells within the
treatment area showed the highest rebound of benzene (35%), followed by GRO (28%).
However, the average rebound percentage of all constituents was -2%, indicating no
rebound and a continued decrease in concentrations. The overall percent reduction in the
monitoring wells inside the treatment area ranged from 2% to 62% for all constituents except
total xylenes, which increased by 10%.
Monitoring wells outside of the treatment area did not exhibit any trends related to the
treatment. Similarly, rebound testing indicated no rebound of concentrations. Overall percent
reductions ranged from 5% to 29% for most constituents, with a 96% increase in
ethylbenzene.
RESULTS: Benzene, BTEX, and TPH in Groundwater
 Over 90% of the dissolved phase benzene and BTEX compounds were removed overall
from the high-oxygen zone around the injection wells (Table 5.1.A), with lower removals
for TPH (2%) which is consistent with the aerobic biodegradation process. Lower
oxygen levels at the monitoring wells located away from the injection wells likely caused
much lower removals of benzene (2%) and toluene (35%) and no removal of
ethylbenzene or xylenes (Table 5.1.B).
 Better removal was associated with the injection well with the fewest operational
problems and lowest initial concentrations (IW-1P, see Figure 5.8).
 In a few specific cases, high DO was correlated to reductions in benzene and BTEX
(Figures 5.4, 5,8, and 5.9).
 Some rebound occurred in the injection wells. Rebound did not affect the overall
reduction in concentrations at these locations, and the overall reduction percentages
were similar compared to the “Before” vs. “After” difference.
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Pulsed Oxygen Biosparging Pilot Test
October 2015
5.3
Soil Data From Before- and After-Test Borings
5.3.1 Visualization of Soil Data
Thirteen paired before- and after-test data provided unexpected results: minimal changes in
benzene and BTEX, and significant increases in soil TPH-All Fractions data. The data
showed considerable variability, with the before- and after-test borings near MW-1, MW-2,
and MW-3 having lower benzene and BTEX concentrations than MW-4, and MW-4 having
the highest TPH-All Fractions sampling results (Figure 5.12). In nine of 13 samples, the
TPH-All Fractions concentrations increased. At all four borings, the highest concentration
present at any depth interval was an after-test sample (Figure 5.12).
Figure 5.13 shows a “triangle plot’, where the concentration of a constituent in the beforetest sample is used for the X-axis, and the after-test concentration is used for the Y-axis.
The resulting plots show changes, either reductions in concentration which fall below the
black 45-degree line, or increases in concentration which fall above the black 45-degree
line. This figure shows slight decreases for most benzene samples, and unexpected
significant increases in TPH for most soil samples.
5.3.2 Before and After Average Concentration
Summary statistics using both arithmetic means and geometric means of all the paired data
show the increase in TPH-ALL Fractions, TPH-GRO, and TPH-DRO (Table 5.2). These
data are log-normally distributed, so:
 the geometric mean provides an indication of the change at any point in the test zone;
 the arithmetic average indicates the change in the cumulative concentration (mass) in
the test zone.
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Pulsed Oxygen Biosparging Pilot Test
October 2015
Table 5.2. Arithmetic
and Geometric
Averages of Beforeand After-Test Soil
Data.
Note: positive
percent reduction
value is a reduction,
negative is an
increase.
The following
constituents and TPH
fractions are not
shown because more
than 50% of the
samples were nondetect







Diisopropyl Ether
(DIPE)
Carbon Chain C6
Carbon Chain
C23-C24
Carbon Chain
C25-C28
Carbon Chain
C29-C32
Carbon Chain
C33-C36
Motor Oil Range
(C28 to C36)
LA LNAPL Workgroup
Arithmetic Average
(for evaluating change in mass)
Toluene
Benzene
BTEX
Ethylbenzene
Xylenes, Total
Naphthalene
Carbon Chain C21-C22
Carbon Chain C9-C10
Carbon Chain C19-C20
Carbon Chain C11-C12
Carbon Chain C17-C18
TPH as Gasoline (C6-C12)
TPH All Fractions (C6-C44)
TPH Diesel Range (C13 to C28)
Carbon Chain C13-C14
Carbon Chain C15-C16
Carbon Chain C7
Carbon Chain C8
Geometric Mean (for
change at any point in tmt. Zone)
Benzene
Toluene
Ethylbenzene
BTEX
Carbon Chain C21-C22
Xylenes, Total
Carbon Chain C17-C18
Carbon Chain C19-C20
Carbon Chain C9-C10
Naphthalene
TPH as Gasoline (C6-C12)
Carbon Chain C11-C12
TPH All Fractions (C6-C44)
TPH Diesel Range (C13 to C28)
Carbon Chain C13-C14
Carbon Chain C15-C16
Carbon Chain C8
Carbon Chain C7
21
Before
(mg/kg)
16
9.1
85.6
10.9
49.6
13.9
126
813
182
1,542
369
2,600
5,151
2,481
1,291
528
139
201
Before
(mg/kg)
1.1
3.8
4.8
24.7
94
13.3
292
143
514
9.4
1,788
1,122
3,604
1,636
843
372
123
98
After
(mg/kg)
13.7
8.1
85.6
11
52.8
19.2
188
1,343
313
2,682
647
4,722
9,361
4,536
2,365
1,037
337
564
After
(mg/kg)
0.83
2.9
4.9
25.7
114
16.1
370
193
699
13.4
2,764
1,746
5,776
2,751
1,463
649
246
214
Percent
Reduction
14%
11%
0%
-2%
-6%
-38%
-50%
-65%
-72%
-74%
-75%
-82%
-82%
-83%
-83%
-96%
-141%
-181%
Percent
Reduction
25%
24%
-2%
-4%
-21%
-21%
-27%
-35%
-36%
-42%
-55%
-56%
-60%
-68%
-74%
-74%
-100%
-119%
Pulsed Oxygen Biosparging Pilot Test
October 2015
Benzene concentrations in soil decreased slightly during test, total BTEX concentrations
stayed about the same, and TPH increased. The result of the increased TPH, however, is
that the mass fraction of benzene and total BTEX dropped significantly during the
biosparge test because the other compounds increased in concentration. When using the
arithmetic averages:

For benzene, the mass fraction dropped from 0.18% to 0.087% (a 51% reduction).

For BTEX, the mass fraction dropped from 1.67% to 0.92% (a 45% reduction).
However, the majority of the reduction was due to toluene and benzene with no
change in concentration of xylene or ethylbenzene. For the remainder of the report,
please note that any discussion of reduction in BTEX soil concentration is driven only
by reduction in benzene and toluene.
The reduction in benzene and BTEX mass fraction indicate that a composition change did
occur due to the oxygen biosparging process.
5.3.3 Statistically Significant Decreases and Increases
The decrease in concentration for the 13 paired samples were statistically analyzed using a
Wilcoxon Signed-Rank Test. This non-parametric test indicated that:

The decrease in benzene, while only 11% for the arithmetic mean, was statistically
significant at the p=0.05 level. This is explained by the distribution of the paired
samples: 11 of the 13 samples showed decreases in benzene, while only two
showed an increase.

Benzene was the only compound that showed a statistically significant decrease in
concentration, but the TPH All Fractions data showed a p-value of 0.08 for a twotailed test, an almost statistically significant increase in concentration compared
to the p=0.05 level.

Both the decrease in benzene and BTEX mass fractions were statistically significant
at the p=0.05 level, with p values of 0.01 and 0.03 respectively.
In summary, the soil data show a statistically significant reduction in the mass fraction of
both benzene and BTEX during the test, confirming a composition change did occur.
While the increase in TPH concentrations in soil before and after the test was not statistically
significant, it was large (55% increase). This may have been due to an actual inflow of
LNAPL during the test (perhaps due to the surging from the oxygen pulses), or may have
been just a low-probability (p = 0.077) result of soil sampling variability. Other before- and
after-test data were analyzed to see if these data supported the hypothesis of significant
LNAPL inflow into the test zone.
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5.3.4 Before-Test CPT and UVOST
The LA LNAPL POBS Pilot Test used a number of LNAPL characterization methods along
with measurements of how groundwater and soil concentrations changed:

The CPT tool provided information on the stratigraphy of the test area (Figure 5.14)
and was the primary method to evaluate the thickness and composition of the aquifer
media in the test zone.

The UVOST test provided a semi-quantitative indication of the presence of LNAPL,
via measurement of the fluorescence response of the polycyclic aromatic
hydrocarbon (PAH) constituents in the LNAPL.
The test area was selected in part based on the ROST (a precursor test to the more recent
UVOST test) and CPT results from PA-11 (Figure 5.14), which showed a thick, permeable
sand unit near the bottom of the boring (~ 50 feet bgs) and much poorer permeability in the
shallow zone and a stronger ROST response in the deeper unit. However, when six
CPT/UVOST borings were advanced in 2012, the opposite seemed to be the prevalent
condition: more sand (yellow color in Figure 5.14) and higher UVOST response in the
shallow unit compared to the deeper unit. This potentially shows some of the pitfalls in
comparing ROST vs. UVOST and illustrates the variability of this very heterogeneous
formation.
In the end, there was significant accumulation of LNAPL in wells screened in the deeper
zone (~45 to 50 feet bgs), but none or limited LNAPL in shallower wells (23-25 feet bgs).
While the 2012 CPT results suggest this shallow unit was a contiguous sand unit in all six
CPT logs, this unit was very difficult to sparge, with the Pilot Test experiencing several
daylighting events due to pore permeability in the injection zone.
5.3.5 Before vs. After UVOST, Core Photography, and Soil Analysis
Because the UVOST responds to PAHs, the UVOST is more useful for measuring the
relative amount and distribution of a uniform LNAPL, but potentially less informative about
compositional change processes that do not preferentially remove PAHs. In other words,
reduction of benzene and BTEX from LNAPL may not materially change the UVOST
response.
Core photography has some of the same limitations, where a UV light is shined on a core
section creating a white image on the core photograph wherever LNAPL is present.
All four core locations had before- and after-test UVOST results which are shown along with
the corresponding CPT logs and small insets of the core photography (Figures 5.15 to 5.18).
In Figures 5.15 and 5.16, the blue image in the UVOST section (the right panel of each log)
is the before-test UVOST response, and the colored, banded response is the after-test
response. In general, the after-test UVOST response was lower than the before-test
LA LNAPL Workgroup
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Pulsed Oxygen Biosparging Pilot Test
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response, suggesting some removal of PAHs from the test area. Interestingly, the most
noticeable response was in MW-3 in the 12-15 foot bgs interval, which is in a clay unit and
significantly higher than the injection zone from 23 to 25 feet bgs. A few intervals seemed to
show a higher after-test response (e.g., MW-3 at 27 feet bgs, but this was atypical).
The key treatment zone between 10 and 30 feet was expanded in Figures 5.17 through 5.19
to show the before- and after-test core photography and soil analysis. In figures, blue
numbers on the left are the before-test TPH-All Fraction data, and the green values on the
right are the corresponding after-test data. The after-test core photographs for MW-3 and
MW-4 are shown in Figure 5.19; however, there are no corresponding before-test photos for
these borings. Additionally, no core was recovered from boring MW-2 between 22 and 24
feet bgs. For the purpose of the analysis, samples immediately above and below the
missing interval were paired with two before-test soil samples collected in the 22 to 24 foot
bgs interval.
The before- and after- soil values show increases in TPH-All Fractions in four of the seven
samples with core photography, but no obvious increase in the white images in the core
photography (Figure 5.19). However, the key 22 to 24 foot bgs interval is missing in the
MW-2 core, leaving the MW-1 core as the key comparison. In the MW-1 core, there
appears to be a much whiter image near the 24 to 25 foot interval, but the rest of the aftertest image has similar or even less white image than the before-test image. Therefore the
hypothesis of inflow of LNAPL is not confirmed by the core photography. While MW-3
shows a very intense after image, the lack of a before-test image makes it difficult to
interpret this observation.
5.3.6 Before vs. After Core Photography and Pore Fluids Analysis
Methods such as the Dean-Stark test are used to measure LNAPL saturation, which is the
percentage of the pore space filled with LNAPL. Two before- and after-test saturation
measurements were taken and are shown in Figure 5.20.
At the first pore saturation location (MW-1), the data showed that LNAPL saturation
decreased from 12.3% of the pore space to 5.5% of the pore space at the 23 feet bgs depth
(Table 5.3). The soil samples (Figures 5.17 and 5.19) taken from near this depth showed an
increase in TPH-All Fractions from 5,500 mg/kg to 17,000 mg/kg at 23 feet bgs.
At the second pore saturation location (MW-2), the two saturation samples were separated
by about 0.5 feet, and showed little difference: 7.7% before vs. 7.6% after-test. The two
nearest soil samples show a decrease from 13,000 mg/kg to 7,800 mg/kg and an increase
from 10,000 mg/kg to 22,000 mg/kg, but these before-and-after sample intervals are
separated by over a foot.
The before and after soil samples generally showed an increase in TPH concentration, the
reason for this trend is unknown. Insufficient LNAPL data collection and the heterogeneity of
the soil analysis prevent any statistically significant conclusions.
LA LNAPL Workgroup
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Table 5.3. Before and After Pore Fluids Analysis Data for Shallow Zone
Before Test
Change
After Test
Depth (ft)
Porosity
(%)
Before
NAPL
Saturation
(%pv)
MW-1
23.2
46.8
12.3
23.5
44.1
5.5
6.8
MW-2
23.6
46.3
7.7
24.1
46.7
7.6
0.1
MW-2
No sample
20.6
50.6
7.1
-
MW-2
No sample
22.3
53.3
7.1
-
Location
Depth (ft)
Porosity
(%)
After NAPL
Saturation
(%pv)
Change
(Before After)
Shallow Zone
LNAPL mobility using a centrifuge test was analyzed at one location before- and after-test
(Table 5.4). A section of the soil core is measured for LNAPL saturation initially, then the
remaining core is centrifuged at 1000 g to remove any mobile LNAPL. After centrifuging,
the LNAPL saturation is measured once again.
The mobility analysis was not supportive of the LNAPL inflow hypothesis. There was some,
but not much mobile LNAPL before the test (mobile fraction of 0.3% of pore space) and zero
afterward. This analysis suggested residual LNAPL was present at the MW-1 location after
the test.
Table 5.4. LNAPL Mobility Test Results Using the Centrifuge Method
Before Test
Location
MW-1
Depth
(ft)
Dry Bulk
Density
(g/cc)
Total
Porosity
(%)
Initial NAPL
Saturation (%pv)
NAPL Sat. After
Centrifuge 1000xG
(%PV)
Mobile LNAPL
Fraction (%)
20-24.5
1.47
45.9
9.5
9.2
0.3
After Test
Location
MW-1
Depth
(ft)
Dry Bulk
Density
(g/cc)
Total
Porosity
(%)
Initial NAPL
Saturation (%pv)
NAPL Sat. After
Centrifuge 1000xG
(%PV)
Mobile LNAPL
Fraction (%)
19-23.9
1.46
46.0
7.9
7.9
0.0
In summary, the LNAPL Pore Fluids analysis did not show an influx of LNAPL, but the
analysis was limited to a single comparison in two separate cores. The soil TPH data, in
LA LNAPL Workgroup
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Pulsed Oxygen Biosparging Pilot Test
October 2015
general, showed a concentration increase suggesting a potential LNAPL inflow during the
test. The LNAPL mobility analysis at core location MW-1 showed LNAPL mobility fell from
0.3% of pore space prior to the Pilot Test to zero mobile fraction after the Pilot Test.
RESULTS: Soil Data




Average benzene concentrations in soil decreased slightly before and after the test (11%
reduction using an arithmetic average). This decrease is statistically significant at the
p=0.05 level. Total BTEX was unchanged (Table 5.1).
The average concentration of the TPH-All Fractions increased by 82% before and after
the test (from 5150 mg/kg to 9360 mg/kg). Both GRO and DRO had similar increases
(Table 5.2). These results were nearly as statistically significant as the benzene results
above.
The mass fraction of both benzene and BTEX decreased by 51% and 45% respectively
during the test (Section 5.3.2). However, the majority of the reduction was due to toluene
and benzene with no change in concentration of xylene or ethylbenzene. These
decreases were statistically significant at the p=0.05 level. This confirms that a
significant composition change (removal of benzene and BTEX) did occur during the
year-long test.
This increase in TPH has two potential explanations: 1) an LNAPL inflow during the test,
potentially due to the surging action of the oxygen pulses; 2) natural variability during the
soil sampling. The UVOST and core photography data do not indicate LNAPL inflow
(Figures 5.17 to 5.19), and the subsequent data analysis (Section 6.4) was performed
assuming this increase was just natural variability.

Only two pairs of before and after LNAPL saturation data were available for analysis.
These two pairs of LNAPL saturation data for MW-1 and MW-2 (Figure 5.20) either
decreased or stayed the same (12.3% – 5.5% and 7.7% – 7.6%). The before and after
soil samples generally showed an increase in TPH concentration (Figure 5.17 and 5.19),
the reason for this trend is unknown. Insufficient LNAPL data collection and the
heterogeneity of the soil analysis prevent any statistically significant conclusions.

Key Figures: 5.12 to 5.20
5.4
Mass Balance Analysis with Increasing TPH Concentrations
A mass balance analysis was performed using the arithmetic averages of the soil data
(Table 5.5).
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Pulsed Oxygen Biosparging Pilot Test
October 2015
Table 5.5. Arithmetic Average Concentration Before and After Pilot Test
Benzene
(mg/kg)
BTEX
(mg/kg)
TPH- ALL
(mg/kg)
GRO
(mg/kg)
DRO
(mg/kg)
Pre-Test
Post-Test
% Reduction
9.1
8.1
11%
86
86
0%
5,151
9,361
-82%
2,600
4,722
-82%
2,481
4,536
-83%
Statistically Significant?
Yes
No
No
No
No
Notes: Negative % Reduction indicates an increase in average concentrations.
GRO = Gasoline Range Organics, DRO = Diesel Range Organics
First, a treatment volume was estimated by calculating the area of the green zone in Figure
3.5 of 2,885 square feet (0.066 acres), and treatment zone thickness of five feet, and a
saturated soil bulk density of 1.9 grams/cm3. This resulted in a treatment volume of 534
cubic yards. The resulting before and after estimated contaminant masses are shown in
Table 5.6.
Table 5.6. Calculated Changes in Mass of Benzene, BTEX, and TPH Fractions
Benzene
(kg)
BTEX
(kg)
TPH-All
(kg)
GRO
(kg)
DRO
(kg)
Before
7.1
66.4
3,995
2,020
1,924
After
6.3
66.5
7,260
3,660
3,518
Change
-0.8
0.1
3,265
1,640
1,594
Note: BTEX, TPH-All, GRO, and DRO showed increases after test.
A more detailed assessment of the mass balance was performed assuming a range of
possible values for the mass of TPH during the test (Table 5.7) using the following
approach:
1) The changes in the mass fraction are representative of the before and after
conditions at the site.
2) The TPH didn’t change during the test, but there is a lower range estimate of the
TPH mass (3,995 kilograms from the before data) and a higher range estimate
(7,260 kilograms from the after data), consistent with Table 5.6.
3) All the calculated BTEX removal was caused by aerobic biodegradation via the
oxygen biosparging.
As shown in Table 5.7, the following mass removal ranges for benzene and BTEX were:
 Benzene: between 3.6 - 6.5 kilograms was removed (51% removal)
 BTEX: between 30 - 55 kilograms was removed (45% removal)
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Pulsed Oxygen Biosparging Pilot Test
October 2015
Note if the increase in TPH was due to LNAPL inflow, then the removal of BTEX would be
close to the high range removals in Table 5.7 (6.5 kg of benzene, 55 kg of BTEX).
Table 5.7. Revised Mass Removal Estimate for Benzene and BTEX
Based on Change in Mass Fraction (assuming increase in TPH was due to sampling variability)
LOW RANGE MASS REMOVAL ESTIMATE
Before
After
Change
TPH Mass
Benzene Mass Fraction
(kg)
(%)
3995
0.18%
3995
0.087%
0
0.09%
BTEX Mass Fraction
Benzene Mass
(%)
(kg)
1.67%
7.1
0.92%
3.5
0.75%
BTEX Mass
(kg)
67
37
30
Before
After
Before-After
7260
0.18%
1.67%
12.8
121
7260
0.087%
0.92%
6.3
67
0
0.09%
0.75%
6.5
55
3.6
HIGH RANGE MASS REMOVAL ESTIMATE
TPH Mass
Benzene Mass Fraction
BTEX Mass Fraction
Benzene Mass
BTEX Mass
(kg)
(%)
(%)
(kg)
(kg)
The removal can be converted to an equivalent value in units of gallons of LNAPL removed
per acre per year, assuming the test area was about 0.066 acres and the test lasted about a
year: between 138 and 253 gallons (of only BTEX) per acre per year from a five-foot
saturated interval. In comparison, the Natural Source Zone Depletion pilot test indicated a
NSZD depletion rate on the order of 1700 gallons per acre per year at the Shell facility.
However, this may not be an appropriate comparison, as the Biosparge removals were
focused on BTEX compounds in the saturated zone, vs. removal of potentially more
compounds for the NSZD process, in both the saturated and unsaturated zone. It is likely
that the calculated volume of removed BTEX is in addition to, or a minor component of,
mass degraded through NSZD.
In addition, one member of the LA LNAPL project team hypothesized that the presence of
wells in the test area may present a pathway for recharge of LNAPL at the top of the water
column, as the vast majority of LNAPL in this area is trapped in submerged lenses. This
could explain the increase in TPH concentrations in soil during the year-long biosparge test,
an increase which was accompanied by statistically significant reductions in benzene and
BTEX mass fraction in soil.
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Pulsed Oxygen Biosparging Pilot Test
October 2015
RESULTS: Mass Balance





The treatment zone size was estimated to be 0.066 acres and 534 cubic yards.
Lower range and higher range estimates of mass removal were calculated using the
lower and higher mass estimates for TPH before and after the test.
Benzene removed: between 3.6 – 6.5 kilograms (51% removal)
BTEX removed: between 30 - 55 kilograms (45% removal), equivalent to 170 to 310
gallons of only BTEX per acre per year from a five-foot saturated interval. The Natural
Source Zeon Depletion Test (NSZD) at the Shell facility measured 1700 gallons of
LNAPL degraded per acre per year, but was measuring the degradation of many LNAPL
components in the entire soil column.
Key Table: 5.7
5.5
Stoichiometric Analysis of Oxygen Injection
A planning level stoichiometric analysis of the amount of oxygen delivered to the test zone
with a range for biodegradation capacity between 1 to 3 kilograms of oxygen required to
degrade one kilogram of BTEX (see Wiedemeier et al., 1999) (the 3:1 ratio assumes no cell
growth; 1:1 ratio assumes cell growth occurred during the test) is shown below:





38,600 SCF of oxygen added to treatment zone, equivalent to:
48,800 moles of oxygen, equivalent to:
1,560 kilograms of oxygen, equivalent to:
The capacity to degrade 1,560 to 520 kilograms of aromatic hydrocarbons
(BTEX) (assuming a 1:1 and 3:1 oxygen: BTEX stoichiometry).
Then assuming the removal of BTEX (between 30 - 55 kg) was all due to
biodegradation (no volatilization), and the range of BTEX mass removed in Table
5.7, then between 1.9% to 10.6% of the oxygen was consumed for BTEX
biodegradation.
RESULTS: Stoichiometric Analysis

If the mass balance estimate based on LNAPL inflow is correct, then potentially 1.9% to
10.6% of the oxygen delivered to the treatment zone was consumed for biodegradation
of BTEX.
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Pulsed Oxygen Biosparging Pilot Test
October 2015
5.6
Key Questions About the Mass Balance Analysis
The mass balance analysis is discussed in a question/answer format below.
If an LNAPL inflow did cause the before- and after-test increase in soil concentrations, why
wasn’t this observed in the ROST, core photography, or LNAPL saturation/mobility data?
Response: The simplest answer is there was no actual increase in TPH concentrations, but
that the 55% increase was the result of sampling variability.
The UVOST data is sensitive to polyaromatic hydrocarbons such as naphthalene, but
naphthalene concentrations increased by 42% during the test (Table 5.2). So the observed
reduction in UVOST signal does not correlate to the soils data for naphthalene. Similarly,
the core photography is conducted using a UV light, which is measuring the same general
constituents as the UVOST.
The limited LNAPL saturation data was inconclusive and did not contribute to answering this
question.
The only complete comparison of core photography to TPH data is at MW-1 (Figure 5.19).
This soil data overall shows about a 60% increase in TPH (average of 6,700 mg/kg before
and 10,700 mg/kg after) for the bottom three samples with corresponding before- and aftercore photos. The bottom sample at 24.3 feet shows a noticeable increase in brightness.
The other two appear to show higher response in the before photo, but this is fairly
subjective. The core photography does not support the inflow theory.
The LNAPL mobility test at MW-1 showed higher before LNAPL saturations with a very
small mobile fraction (0.3%) before the test, and lower saturations with no mobility after the
test (Table 5.5). These limited data do not support LNAPL inflow during the test.
Overall, it is more likely that the increase in TPH was due to sampling variability, even
though the increase in TPH concentrations was almost statistically significant.
Are there any other data that suggest that LNAPL inflow occurred during the test?
Response: Not really. First, LNAPL accumulation in all seven wells was tested throughout
the test. In the beginning one monitoring well (MW-4) and one background well (MW-7) had
LNAPL accumulations during startup and during each of the subsequent monitoring events.
Then LNAPL appeared in monitoring well MW-3 in August 2013, two months after the test
was completed, indicating mobile LNAPL had reached this well located in the very center of
the test area. In December 2013 LNAPL was observed in IW-2P. The appearance of
mobile LNAPL in these wells suggests that LNAPL inflow is possible in this area. But there
was no observed LNAPL accumulation in the monitoring wells during the test, arguing
against LNAPL inflow.
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Pulsed Oxygen Biosparging Pilot Test
October 2015
Second, the groundwater data (Table 5.1) show an increase for only one contaminant class:
TPH Motor oil. This fraction is the least aerobically degradable, and increased by 12%
during the test.
Is the TPH data controlled by the one after-test sample collected at MW-4 at 22.5 feet bgs,
where the TPH-All Fraction data increased from 3,000 mg/kg to 29,000 mg/kg?
Response: This sample has a significant effect but not controlling effect on the mass
balance. If this sample pair is removed, the TPH-All Fraction data still increases by 45%
(5,330 mg/kg to 7,724 mg/kg), compared to the 82% increase in the complete database
(5,131 mg/kg to 9,361 mg/kg).
Is it possible that most of the removal of benzene and BTEX was from volatilization and not
from aerobic biodegradation? In other words, this was more of an air sparging process than
biosparging?
Response: A typical three-well air sparging system would have delivered approximately
75,000 SCF of air to the subsurface in one week (Newell, 2012), assuming a 5 SCFM
injection rate for each well and pulsing with 50% on-time. The POBS system for this Pilot
Test only averaged about 700 SCF of gas injection per week. Therefore the amount of
volatilization that would have occurred from this test would be much less (potentially 99%
less) than an air sparging system.
If volatilization is the primary method of removal, then there should be a trend of higher
removal for compounds with higher Henry’s Law coefficient (which depends on how easy it
is to remove chemicals from the dissolved phase) or the vapor pressure (which shows how
easy it is to remove chemicals from the NAPL phase).
However, there did not appear to be a correlation between the two volatilization parameters
(Table 5.8) and removal (Table 5.2) for the BTEX compounds. As shown in Table 5.8, the
highest values are in green with largest fonts, the lowest in red in small fonts, and don’t
appear to show any correlation.
Table 5.8. Volatilization Parameters for the BTEX Compounds vs. Percentage Removal
Toluene
Benzene
Ethylbenzene
Total Xylenes
Henry's
Law Coeff.
(-)
Vapor
Pressure
(mm Hg)
Percent
Removal in Soil
(%)
0.26
0.22
0.32
0.29
3
95
10
7
14%
11%
-2%
-6%
Finally, a mass balance was performed where the initial groundwater concentrations for the
BTEX compounds were assumed to be in contact with the oxygen gas during the entire test,
LA LNAPL Workgroup
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Pulsed Oxygen Biosparging Pilot Test
October 2015
and it was assumed that the oxygen volatilized these compounds out of the groundwater in
proportion to their Henry’s Law coefficient. For example, 38,600 SCF is equivalent to about
1 million liters of gas. Assuming a concentration of 335 µg/L for benzene (using the
geomean of both pre- and post-test injection and monitoring well data) and a unitless
Henry’s Law coefficient of 0.22, the vapor phase concentration assuming complete
equilibrium between the gas and water phases would be 1523 µg benzene per liter of gas.
When multiplied together, the 1.09 million liters of gas could only strip about 1.7 kg.
This calculation was repeated for the before-test BTEX compounds, and when combined,
indicates that the 38,600 SCF of oxygen could have stripped only 5.43 kilograms of BTEX
from the groundwater, less than the low range estimate of 30 - 55 kilograms in Table 5.7.
Through similar calculations, the vapor phase concentration of benzene partitioning from
LNAPL using vapor pressure of benzene indicated only 1.0 kg of benzene would have been
removed if all the injected gas was in equilibrium with LNAPL
While there certainly was some volatilization that occurred, any stripped volatiles would have
been either trapped as residual oxygen bubbles in the groundwater, which would then have
been biodegraded, or carried to the water table by the oxygen channels. The presence of
oxygen and volatile aromatic compounds here would likely mean biodegradation of volatiles
in the vadose zone. In summary, it is very unlikely that any removal of volatile, aerobically
degradable compounds would not have resulted in biodegradation except in the unusual
circumstances of “daylighting” or short circuiting.
RESULTS: Key Questions

A number of questions regarding key elements of the data analysis and conceptual
model are asked and discussed in this section.
6.0
PILOT TEST PERFORMANCE SUMMARY
The POBS post-test analysis was designed to evaluate the effectiveness and cost efficiency
of applying POBS full scale for LNAPL remediation. The test results were analyzed to
present the following performance metrics:
6.1
Change in LNAPL Mass in Treatment Zones
The before- and after-test soil data were used to determine the following changes in LNAPL
mass, assuming that the increase in TPH concentrations were due to sampling variability
(see Section 5.8):



LNAPL Mass Change During Test: assumed no change (as TPH-All Fractions)
Benzene removed: between 3.6 - 6.5 kilograms (51% removal)
BTEX removed: between 30 - 55 kilograms (45% removal)
LA LNAPL Workgroup
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Pulsed Oxygen Biosparging Pilot Test
October 2015
6.2
Change in Apparent LNAPL Thickness at Wells in Treatment Zones
There was very little change in apparent thickness in the monitoring wells. Wells MW-4 and
MW-7 had apparent LNAPL thickness after the first pre-test sampling event, and were not
sampled during the test. No other major occurrences of LNAPL accumulations were
observed in the monitoring wells.
6.3
Change in Concentration and Mass Discharge (Mass Flux) in Treatment Zones
To calculate mass discharge, the change in the geomean for both the injection wells and the
monitoring wells was performed, because the downgradient vertical control plane over which
mass discharge is evaluated would intersect groundwater that flows by both the injection
and monitoring wells. Before and after geometric mean concentrations for injection wells
and monitoring wells within the treatment area showed that benzene concentrations
dropped from 844 µg/L to 133 µg/L (84% reduction), and BTEX concentrations from 2,672
µg/L to 690 µg/L (74% reduction).
The change in mass discharge is directly related to the change in dissolved phase
concentrations. For this test, groundwater sampling was conducted two months before and
two months after the year-long Pilot Test. Mass discharge is a function of the vertical area
of flowing groundwater, groundwater Darcy velocity, and the dissolved phase concentration.






Groundwater Seepage Velocity = average of 2.3 feet/year (URS/GSI, 2010)
Saturated thickness = 5 feet
Arbitrary width = 500 feet
Porosity = 0.2
Geometric mean benzene concentration of injection wells and monitoring wells inside
treatment area before the test = 844 µg/L
Geometric mean benzene concentration of injection wells and monitoring wells inside
treatment area after the test = 133 µg/L
Using the above values, the mass discharge before the test would be 0.08 grams benzene
per day, and the mass discharge after would be 0.012 grams benzene per day, an 84%
reduction in mass discharge.
6.4
Change in LNAPL Mobility
As a phase-change technology, the POBS technology is not expected to have a large effect
on LNAPL mobility.
The before-test LNAPL mobility testing using the centrifuge method indicated that 0.3% of
the LNAPL was removable by centrifuging. The after-test data showed no mobility (i.e., 0%
of LNAPL removed by the centrifuge). This is not likely due to any response of the LNAPL
to the oxygen biosparging, however.
LA LNAPL Workgroup
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Pulsed Oxygen Biosparging Pilot Test
October 2015
LNAPL in two monitoring wells were discovered right during startup (monitoring well MW-4
and background well MW-7). These wells were located to the northeast edge of the
treatment zone and beyond. In August 2013, two months after project shutdown, LNAPL
was observed in MW-3, indicating mobile LNAPL had entered the treatment zone. In
December 2013, LNAPL was observed in injection well IW-2P for the first time. Overall the
test data does not indicate that LNAPL mobility was changed by the POBS process.
6.5
Change in LNAPL Composition in the Treatment Zones
As expected with a composition change technology, the soil data showed a substantial
reduction in the mass fraction of benzene and BTEX in LNAPL during the test.

For benzene, the mass fraction dropped from 0.18% to 0.087% (a 51% reduction).

For BTEX, the mass fraction dropped from 1.67% to 0.92% (a 45% reduction).
6.6
Concentrations of DO in the Treatment Zones
DO data (Figure 5.4) started low, then increased in the injection wells (up to > 14 mg/L in
some wells), and finally showed small increases (< 3 mg/L) in the monitoring wells during
the test. These results suggest that the biosparge test was being pushed to treat a zone
with considerable organic load in the form of LNAPL, and that even a year of biosparging
(with a significant increase in sparge volume over initial plans) did not allow high
concentrations of DO to persist throughout the treatment zone
6.7
Cost of Treatment when Applied to Full Scale
Planning level, ± 50% costs for construction of the POBS system are provided below,
adjusted for only the treatment system. Matrix Oxygen Injection Systems provides these
costs:




Skid mounted systems from 12 to 64 injection points; capital cost from $48K to
$105K.
Injection point installation costs generally range from $350 for shallow overburden
points and up to $1,000 for deep overburden or bedrock points.
$0.15 to $0.24 per point per day for electricity
30% of wells need to be replaced each year
These costs were used to construct a low-end cost estimate for a refinery-terminal setting.
Each injection point was assumed to cost $1K with another $1K in associated
trenching/piping and site work. A $105K skid for 62 points was assumed (the midpoint of
the reported skid-mounted unit). Because of the high oxygen delivery rate used for this test,
an O&M cost of $0.12 per point per day was assumed, double the high-end electricity cost
to account for the high oxygen delivery rates used for this pilot test. To treat a 20-acre zone
would require 1,233 injection points and 20 skids. To account for design/approvals costs,
the capital cost subtotal was increased by 25%.
LA LNAPL Workgroup
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Pulsed Oxygen Biosparging Pilot Test
October 2015
Based on the operational problems of this biosparging project, it was assumed that 30% of
the wells would require replacement or extensive rework every year. The O&M on the skids
and overall system would require 15% of skid capital cost every year (6.7 year replacement
period).
Normalizing to area, a planning-level low-range cost was estimated for a large scale
deployment of the technology. The high end doubled to account for the potential difficulty in
drilling/operating in a refinery environment and the difficulties with biosparging associated
with this pilot test, and to acknowledge the very general, planning level nature of these cost
estimates.


Capital cost:
Annual O&M Cost:
$300K to $600K per acre
$60K to $120K per acre
Note these capital costs are on the low end of capital costs plus O&M costs for in-situ
treatment of $1 million to $5 million per acre (e.g., Sale et al., 2008). However, this cost
estimates assumes only one vertical transmissive interval (no more than 20 feet thick) being
treated. Multiple vertical injection points designed to treat multiple transmissive layers would
increase the per-acre costs.
RESULTS: Performance Metrics

Seven performance metrics outlined in the Pilot Test work plan are evaluated in this
section:
Change in LNAPL Mass; LNAPL Apparent Thickness; Groundwater
Concentration/Mass Flux; LNAPL Mobility; LNAPL Composition; and DO. The seventh
metric was a planning level capital and O&M cost to perform a large scale
implementation of the technology in dollars per acre.
LA LNAPL Workgroup
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Pulsed Oxygen Biosparging Pilot Test
October 2015
7.0
REFERENCES
Brown and Caldwell. (2007). Site Assessment Report, Former Process Area, Shell Carson
Terminal, Carson, California. Prepared for Regional Water Quality Control Board, Los
Angeles Region, May 2007.
Bass, D. H., Brown, R.A., and Hastings, N.A. (2000). Performance of air sparging systems:
a review of case studies. Journal of Hazardous Materials 72: 101-119.
Geosyntec Consultants and URS Corporation. (2007). Light Non-Aqueous Phase Liquid
(LNAPL) Investigation. Shell Oil Products Carson Terminal, Carson, California. Prepared
for Equilon Enterprises LLC. December 2007.
Geosyntec Consultants. (2008a). Light Non-Aqueous Phase Liquid (LNAPL) Recovery Pilot
Test and Recovery Modeling Report. Shell Oil Products Carson Terminal, Carson,
California. Prepared for Shell Oil Products US. May 2008.
Geosyntec Consultants. (2008b). Supplemental Light Non-Aqueous Phase Liquid (LNAPL)
Recovery Pilot Test and Recovery Modeling Report. Shell Oil Products Carson Terminal,
Carson, California. Prepared for Shell Oil Products US. August 2008.
Klinchuch, L.A., Goulding, N., James, S.R., and J.J. Gies. (2007). Deep Air Sparging – 15 to
46m beneath the Water Table. Ground Water Monitoring & Remediation. 27(3): 118-126.
Leeson, A., Johnson, P.C., Johnson, R.L., Vogel, C.M., Hinchee, R.E., Marley, M., Peargin,
T., Bruce, C.L., Amerson, I.L., Coonfare C.T., Gillespie, R.D., and D.B. McWhorter.
(2002). Air Sparging Design Paradigm, Batelle, Columbus, Ohio.
Los Angeles LNAPL Working Group, 2011. Light Non-Aqueous Phase Liquids (LNAPL)
Literature Review Version 1.0,
Western States Petroleum Association, Torrance, California.
Newell, C.J., 2012. Air Sparging. vs. Oxygen Biosparging, Memo to LA LNAPL Workgroup,
Oct. 29, 2012.
NFESC, (2001). Air Sparging Guidance Document, Technical Report TR-2193-ENV, Naval
Facilities Engineering Service Center, Port Hueneme, California.
Peargin, T. 2010. Personal Communication.
Sale, T., C. Newell, H. Stroo, R. Hinchee, and P. Johnson, (2008), Frequently Asked
Questions Regarding Management of Chlorinated Solvent in Soils and Groundwater,
Developed for the Environmental Security Testing and Certification Program (ER-0530).
http://www.gsi-net.com/Publications/papers2.asp
Shell Global Solutions (US) Inc. (2007). Oxygen Pulse Injection System (OPIS), Design and
Installation Guidance Document. November 2007 Update.
URS Corporation. (2007) Soil Vapor Extraction and Air Sparge Pilot Test Report, Shell
Carson Terminal. October 2007.
LA LNAPL Workgroup
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Pulsed Oxygen Biosparging Pilot Test
October 2015
URS/GSI, 2010. Work Plan for Pulsed Oxygen Biosparging (POBS) Pilot Test, LA LNAPL
Workgroup.
USACE. (2008). In-Situ Air Sparging Engineering and Design Manual, EM1110-1-4005, US
Army Corps of Engineers, Washington, D.C. 31 January 2008.
Wiedemeier, T.H., Rifai, H.S., Newell, C.J., and Wilson, J.W., 1999. Natural Attenuation of
Fuels and Chlorinated Solvents. John Wiley & Sons, New York.
LA LNAPL Workgroup
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Pulsed Oxygen Biosparging Pilot Test
October 2015
FIN
NAL RE
EPORT FOR PU
ULSED
D OXYG
GEN
BIO
OSPAR
RGING (POBS)
(
) PILOT
T TEST
FIG
GURES
LA LN
NAPL Workgrou
up
Figures-1
Pulsed Oxygen Biosparging Pilot Te
est
October 2015
Figure 3.1. Site Location and Layout
LA LNAPL Workgroup
Figures-2
Pulsed Oxygen Biosparging Pilot Test
October 2015
Figure 3.2. Site NAPL Distribution
LA LNAPL Workgroup
Figures-3
Pulsed Oxygen Biosparging Pilot Test
October 2015
LA LNAPL Workgroup
Figures-4
Pulsed Oxygen Biosparging Pilot Test
October 2015
Figure 3.3. Pulsed Oxygen Biosparging (POBS) System Pilot Test Focus Area
LA LNAPL Workgroup
Figures-5
Pulsed Oxygen Biosparging Pilot Test
October 2015
Figure 3.4
4. Original De
esign for Bio
osparge Welll Constructio
on and CPT
T/ROST
Charac
cterization D
Data
(A) Double-nested biospa
arging well installation in separatte boreholes, and (B)
atigraphy and ROST delineation res
sults in the vvicinity of the
e proposed POBS pilot
stra
testt, and appro
oximate well installation depths with
hin the treattment zoness at location
PA11 (5 ft well sumps not shown).
s
Du
ue to LNAPL
L accumulatio
on in deepe
er unit wells,
bios
sparging of the
t deeper unit
u was not conducted.
LA LN
NAPL Workgrou
up
Figures-6
Pulsed Oxygen Biosparging Pilot Te
est
October 2015
Figure 3.5. Pilot Test Layout with Biosparge and Monitoring Locations
Note: Monitoring well and biosparge well locations will be used for pre and post test
characterization. Nested biosparge wells (PB-IW) and monitoring wells (PB-MW) will
be installed in the treatment zones within the Perched Zone (P) and lower Perched
Zone (P2) at the site.
LA LNAPL Workgroup
Figures-7
Pulsed Oxygen Biosparging Pilot Test
October 2015
Figure 3.6. Conceptual POBS System Components
LA LNAPL Workgroup
Figures-8
Pulsed Oxygen Biosparging Pilot Test
October 2015
Figure 4.1. Final Locations of POBS Injection and Monitoring Wells.
LA LNAPL Workgroup
Figures-9
Pulsed Oxygen Biosparging Pilot Test
October 2015
InjectionVolumePerDay
(SCF)
Figure 4.2. Daily Injection Well Volumes for Injection Wells IW-1P (top), IW-2P (middle),
and IW-3P and IW-3R (bottom) in Units of SCF per day.
Injection Well IW-1P
140
120
100
80
60
40
20
Injection Well IW-2P
140
Increase in
injection volumes
all three wells
InjectionVolumePerDay(SCF)
0
120
100
80
60
Daylighting
40
20
InjectionVolumePerDay
(SCF)
0
140
Injection Well IW-3P
120
Short
Circuiting
100
80
60
Injection Well IW-3R
Daylighting
40
20
0
LA LNAPL Workgroup
Figures-10
Pulsed Oxygen Biosparging Pilot Test
October 2015
Figure 5.1. Output from Downhole Sensor Over Four Days, Showing Injection Signal in
Pressure and Conductivity, But Problem with DO and ORP sensors.
LA LNAPL Workgroup
Figures-11
Pulsed Oxygen Biosparging Pilot Test
October 2015
Figure 5.2. Dissolved Oxygen and ORP After Two Months of Operation. Only IW-3P Showed Any Response to the Pulsing.
LA LNAPL Workgroup
Figures-12
Pulsed Oxygen Biosparging Pilot Test
October 2015
Figure 5.3. Dissolved Oxygen Utilization Twelve Hours After Oxygen Pulse In One
Injection Well
PB-IW-1P
ORP
35
DO
Pressure
Conductivity
5800
ORP (V)/DO (mg/L)/P (ft H2O)
30
Dissolved
Oxygen
Conductivity (mS/cm)
25
5750
20
15
10
5
0
10:30
-5
5700
13:30
16:30
19:30
22:30
-10
LA LNAPL Workgroup
1:30
4:30
7:30
10:30
5650
Figures-13
Pulsed Oxygen Biosparging Pilot Test
October 2015
Figure 5.4. Dissolved Oxygen in Groundwater:
All Injection (Tan color), Monitoring (Green), and Background (Grey) Wells, June 2012 to February 2013.
(Note different Y-Axis scales for Injection vs. Monitoring/Background Wells)
LA LNAPL Workgroup
Figures-14
Pulsed Oxygen Biosparging Pilot Test
October 2015
Figure 5.5. Benzene Concentrations in Groundwater vs. Time in All Wells (in ug/L)
Benzene Groundwater Concentration Trends
(All Wells)
End of Pilot Test
100,000
Benzene Concentration (ug/L)
PB‐IW‐1‐P
PB‐IW‐2‐P
PB‐IW‐3‐P
PB‐MW‐1‐P
PB‐MW‐2‐P
PB‐MW‐3‐P
PB‐MW‐4‐P
PB‐MW‐5‐P
PB‐MW‐6‐P
PB‐MW‐7‐P
10,000
1,000
100
10
1
‐2
0
2
4
6
8
10
12
14
16
18
20
22
24
26
28
30
Months Since Start of System Operation
LA LNAPL Workgroup
Figures-15
Pulsed Oxygen Biosparging Pilot Test
October 2015
Figure 5.6. BTEX Concentrations in Groundwater vs. Time in All Wells (in ug/L)
PB‐IW‐1‐P
PB‐IW‐2‐P
PB‐IW‐3‐P
PB‐MW‐1‐P
PB‐MW‐2‐P
PB‐MW‐3‐P
PB‐MW‐4‐P
PB‐MW‐5‐P
PB‐MW‐6‐P
PB‐MW‐7‐P
BTEX Groundwater Concentration Trends
(All Wells)
BTEX Concentration (ug/L)
100,000
End of Pilot Test
10,000
1,000
100
10
1
‐2
0
2
4
6
8
10
12
14
16
18
20
22
24
26
28
30
Months Since Start of System Operation
LA LNAPL Workgroup
Figures-16
Pulsed Oxygen Biosparging Pilot Test
October 2015
Figure 5.7. TPH Concentrations in Groundwater vs. Time in All Wells (in ug/L)
TPH (All Fractions) Groundwater Concentration Trends
(All Wells)
TPH Concentration (mg/L)
100,000
10,000
PB‐IW‐1‐P
PB‐IW‐2‐P
PB‐IW‐3‐P
PB‐MW‐1‐P
PB‐MW‐2‐P
PB‐MW‐3‐P
PB‐MW‐4‐P
PB‐MW‐5‐P
PB‐MW‐6‐P
PB‐MW‐7‐P
1,000
End of Pilot Test
100
10
1
‐2
0
2
4
6
8
10
12
14
16
18
20
22
24
26
28
30
Months Since Start of System Operation
LA LNAPL Workgroup
Figures-17
Pulsed Oxygen Biosparging Pilot Test
October 2015
Figure 5.8. Benzene in Groundwater:
All Injection (Tan color), Monitoring (Green), and Background (Grey) Wells, June 2012 to August 2013.
LA LNAPL Workgroup
Figures-18
Pulsed Oxygen Biosparging Pilot Test
October 2015
Figure 5.9. BTEX in Groundwater:
All Injection (Tan color), Monitoring (Green), and Background (Grey) Wells, June 2012 to August 2013.
LA LNAPL Workgroup
Figures-19
Pulsed Oxygen Biosparging Pilot Test
October 2015
Figure 5.10. TPH (All Fractions) in Groundwater:All Injection (Tan color), Monitoring (Green), and Background (Grey) Wells, June
2012 to August 2013.
LA LNAPL Workgroup
Figures-20
Pulsed Oxygen Biosparging Pilot Test
Geomean
TPH-All Fract.
Concentrations (ug/L)
Geomean BTEX
Concentrations (ug/L)
Figure 5.11. Summary Statis
stics for
B
Benzene, BTEX
X, and TPH-All Fractions
F
in Groundwater: All Injecttion
(Blue color), Monitoring
M
(Gree
en), and
Background (Ye
ellow) Wells, Ju
une 2012
to August
A
2013.
Geomean Benzene
Concentrations (ug/L)
October 2
2015
L
LA LNAPL Workgro
oup
Figure
es-21
Pulsed Oxyge
en Biosparging Pilo
ot Test
October 2015
Figure 5.12. Soil Analysis Results for Benzene, BTEX, and TPH (all samples). NOTE: Each bar (either before or after) is shown at
the actual depth the sample was collected. In most cases there are paired samples very near to one another, but the actual depth of
each sample was used to plot on the y-axis of the graph.
Soil Benzene Profile (MW‐1‐P)
Screen
Depth ( bgs)
0.8
23.0
1.50
24.0
1.80
0.82
0
39.6
23.0
23.5
35
44.7
20
30
40
50
60
70
80
90
100
32
100
200
0.470
0.230
400
5,000
10,000
15,000
20,000
39.1
3,900
21.0
10.4
2,500
21.5
23.5
22.0
22,000
41
Depth ( bgs)
1.0
23.0
22.5
39
23.0
23.5
24.0
22.0
10,000
22.5
13,000
23.0
23.5
24.0
0
24.0
1.5
63.5
24.5
7,800
24.5
10
20
30
40
50
60
70
80
90
100
24.5
0
50
100
150
Soil Concentra on (mg/kg)
200
250
300
350
400
450
500
550
0
5,000
10,000
Soil Concentra on (mg/kg)
16.0
20,000
25,000
30,000
20,000
25,000
30,000
Soil TPH Profile (MW‐3‐P)
16.0
6
4,700
5.0
18.0
18.0
15,000
Soil Concentra on (mg/kg)
Soil BTEX Profile (MW‐3‐P)
Soil Benzene Profile (MW‐3‐P)
0.2
0.220
30,000
Soil TPH Profile (MW‐2‐P)
63.8
1.0
25,000
Soil Concentra on (mg/kg)
21.5
22.5
17.0
1,800
0
500
20.5
21.0
0.8
16.0
17,000
4,400
Soil BTEX Profile (MW‐2‐P)
Depth ( bgs)
Depth ( bgs)
300
20.5
0
5,500
Soil Concentra on (mg/kg)
Soil Benzene Profile (MW‐2‐P)
22.0
14,000
23.0
24.5
0
20.5
21.5
11,000
22.5
24.0
Soil Concentra on (mg/kg)
21.0
22.0
23.5
20
24.5
10
Screen
590
21.5
48
22.5
24.0
24.5
3.3
22.0
23.5 1.2
Post‐Test (mg/kg)
160
21.5
1.50
Pre‐Test (mg/kg)
21.0
1.6
Depth ( bgs)
0.12
22.0
22.5
Soil TPH Profile (MW‐1‐P)
20.5
21.0
0.10
21.5
Depth ( bgs)
20.5
Post‐Test (mg/kg)
21.0
Pre‐Test (mg/kg)
Post‐Test (mg/kg)
Screen
Soil BTEX Profile (MW‐1‐P)
Pre‐Test (mg/kg)
20.5
6,900
18.0
19.0
20.0
22.0
23.0
24.0
25.0
8.6
22.0
24.0
0.7
26.0
27.0
28.0
10.0
20.0
30.0
40.0
50.0
60.0
70.0
80.0
90.0
5,000
28.0
0
50
100
150
200
250
300
350
400
450
500
550
0
5,000
Soil Concentra on (mg/kg)
Soil Benzene Profile (MW‐4‐P)
10,000
15,000
Soil Concentra on (mg/kg)
Soil BTEX Profile (MW‐4‐P)
Soil TPH Profile (MW‐4‐P)
16.0
16.0
1.13
0.225
18.0
0.043
20.0
18.0
1.33
20.0
64.0
22.0
60
24.0
312
22.0
461
24.0
46.0
26.0
522
26.0
39.0
28.0
355.0
28.0
10
20
30
40
50
60
Soil Concentra on (mg/kg)
LA LNAPL Workgroup
70
80
90
100
1,8001,800
20.0
Depth ( bgs)
Depth ( bgs)
Depth ( bgs)
24.0
3,100
28.0
100.0
16.0
0
8,500
26.0
36.5
Soil Concentra on (mg/kg)
18.0
3,000
22.0
29
26.0 0.7
0.0
20.0
9
Depth ( bgs)
0.2
21.0 0.2
Depth ( bgs)
Depth ( bgs)
20.0
3,000
22.0
29,000
24.0
3,400
26.0
4,800.0
28.0
0
50
100
150
200
250
300
350
Soil Concentra on (mg/kg)
Figures-22
400
450
500
550
0
5,000
10,000
15,000
20,000
25,000
30,000
Soil Concentra on (mg/kg)
Pulsed Oxygen Biosparging Pilot Test
October 2
2015
Figure 5.13. Soil Data
D
Posted on Triangle
e Chart, With
h Before-Tesst Concentra
ations on X-A
Axis
and After-Test
A
Co
oncentration on Y-Axis. Results sho
ow slight deccreases for m
most benzen
ne
samples, and
a large inc
creases for m
most TPH sa
amples.
Benzene In
n Soil Before an
nd After Pilot T
Test
AFTER TEST Concentration (ug/kg)
AFTER TEST Concentration (ug/kg)
BTEX In Soil Before an
nd After Pilot TTest
100,0000
100,000
10,000
1,000
100
10
10
100
1,000 10,0
000 100,0001,000
0,000
BEFO
ORE‐TEST Concentration (ug//kg)
1,000,0
000
1,000,0000
GRO In Soil Before and A
After Pilot Test
AFTER TEST Concentration (ug/kg)
1,000,000
10,0000
1,0000
1100
10
10
100,0
000
1000
1,000 10,0
000 100,0001,000
0,000
BEFO
ORE ‐TEST Con
ncentration (ug/kg)
1,000,0000
AFTER TEST Concentration (ug/kg)
DRO In SSoil Before and
d After Pilot Teest
100,0000
10,0
000
1,0
000
100
1
10
10
100
0
1,000 10,0
000 100,0001,000
0,000
BEFO
ORE ‐TEST Conccentration (mgg/kg)
10,0000
1,0000
1100
10
10
1000
1,000 10,0
000 100,0001,000
0,000
BEFO
ORE ‐TEST Con
ncentration (ugg/kg)
TPH In So
oil Before and After Pilot Tesst
1,000,0
000
AFTER TEST Concentration (ug/kg)
100,0
000
10,0
000
1,0
000
100
1
10
10
100
0
1,000 10,0
000 100,0001,000
0,000
BEFO
ORE ‐TEST Conccentration (ug//kg)
LA LNAPL Workgroup
Figures-23
Pulsed Oxygen Biosparging Pilot Te
est
October 2
2015
Figure 5.14. Cone Pen
netrometer (CPT) and UV Optic
cal Screening Tool
T
(UVOST) L
Logs. (See Figu
ure 5 for Locatio
ons)
MW-5
CPT
PA-11 (2
2007)
ROST/C
CPT
IW-1
UVO
OST/CPT
MW-3
UVOST/CPT
U
IW-2
UVOST/CPT
MW-4
UVOST/CP
PT
MW-7
CPT
T
Sc
creened
Inttervals
Key Points:
nificant differenc
ce between 200
07 ROST and CPT
C
Log (PA11) vs. 2012 UVOS
ST, CPT Data (a
all others)
 Sign
 No LNAPL accumu
ulation noted in wells
w
screened in upper unit (see screen intervval symbols on each log)
 Gre
eater than 20 fee
et LNAPL accum
mulation in wells
s screened in de
eeper unit.
L
LA LNAPL Workgro
oup
Figure
es-24
Pulsed Oxyge
en Biosparging Pilo
ot Test
October 2
2015
Figure 5.15. Cone
C
Penetrome
eter (CPT) , Beffore and After UV
U Optical Scree
ening Tool (UVO
OST), and Core
e Photography ffor Borings
MW
W-1 and MW-2. (See Figure 5 for
f Locations)
L
LA LNAPL Workgro
oup
Figure
es-25
Pulsed Oxyge
en Biosparging Pilo
ot Test
October 2
2015
Figure 5.16. Cone
C
Penetrome
eter (CPT) , Beffore and After UV
U Optical Scree
ening Tool (UVO
OST), and Core
e Photography ffor Borings
MW
W-3 and MW-4. (See Figure 5 for
f Locations)
L
LA LNAPL Workgro
oup
Figure
es-26
Pulsed Oxyge
en Biosparging Pilo
ot Test
October 2
2015
Figure 5.17. Before
B
and After Test UV Optica
al Screening Tool (UVOST), an
nd TPH-All Fractions Data
for Boring
gs MW-1 and MW-2..
M
(See Fig
gure 5 for Locattions)
L
LA LNAPL Workgro
oup
Figure
es-27
Pulsed Oxyge
en Biosparging Pilo
ot Test
October 2
2015
Figure 5.18. Before
B
and After Test UV Optica
al Screening Tool (UVOST), an
nd TPH-All Fractions Data
for Boring
gs MW-3 and MW-4.
M
(See Figure 5 for Locatio
ons)
L
LA LNAPL Workgro
oup
Figure
es-28
Pulsed Oxyge
en Biosparging Pilo
ot Test
October 2
2015
Fig
gure 5.19. Core
e Photography and TPH Data
L
LA LNAPL Workgro
oup
Figure
es-29
Pulsed Oxyge
en Biosparging Pilo
ot Test
October 2
2015
Figure 5.2
20. Core Photo
ography and Tw
wo Before-and A
After-Test LNAP L Saturation Re
esults
L
LA LNAPL Workgro
oup
Figure
es-30
Pulsed Oxyge
en Biosparging Pilo
ot Test
APPEN
NDIX 1: PILOT TEST D
DATA
ssued: Octob
ber 2015
Is
Prepared
P
by:
The
T LA LNAP
PL Workgrou
up
AE
ECOM
999
9 Town and Coun
ntry Rd., Orange
e, CA 92868
tel. 714.567.2430
GS
SI Environmental Inc
c.
2211 Norfolk, Suite
e 1000, Houston, Texas 77098-4
4054
tel. 713.522.6300
Table of Contents
1.0
APPENDIX 1: PILOT TEST DATA
1
1.1
FLUID LEVEL MEASUREMENTS AND APPROXIMATE VOLUME OF FREE PRODUCT IN WELL CASING
PRIOR TO WELL DEVELOPMENT
DEPTH TO WATER AND LNAPL DATA
GROUNDWATER MONITORING RESULTS
GROUNDWATER MONITORING RESULTS (DISSOLVED OXYGEN)
BEFORE AND AFTER SOIL RESULTS
1
2
3
7
8
1.2
1.3
1.4
1.5
LA LNAPL Workgroup
Pulsed Oxygen Biosparging Pilot Test
GSI Job No. G-3195-102
Issued: 8 August 2014
Page 1 of 1
FLUID LEVEL MEASUREMENTS AND APPROXIMATE VOLUME OF FREE PRODUCT IN WELL CASING PRIOR TO WELL DEVELOPMENT
Biosparge Pilot Test Area, Carson Terminal
WELL ID
PB-MW-1P
PB-MW-2P
PB-IW-1P
PB-IW-3P
PB-MW-1P2
PB-MW-2P2
PB-IW-1P2
PB-IW-3P2
Screen
Interval (ft
BGS)
21-24
21-24
22-24
22-24
40-43
41-44
42-44
42-44
Depth to Product Depth to Water
Depth to
Depth to Water
(ft BTOC)
(ft BTOC)
Product (ft BGS)
(ft BGS)
17.19
14.2
17.45
14.5
15.25
14.8
15.07
14.6
18.5
40.28
15.5
37.3
18.54
45.61
15.5
42.6
16.08
43.4
15.6
42.9
15.9
42.65
15.4
42.1
BTOC = Below Top of Casing
BGS=Below Ground Surface (approximate)
Approximate
Well
Internal
Approximate Volume
Thickness of Diameter Volume of
of Product in Well
Product (ft) (inches) casing (gal/ft)
Casing (gal)
4
0.653
4
0.653
2
0.163
2
0.163
21.8
4
0.653
14.2
27.1
4
0.653
17.7
27.3
2
0.163
4.5
26.7
2
0.163
4.4
GSI Job No. G-­‐3195
Issued: 8 August 2014
Page 1 of 1
Depth to Water and LNAPL Data
LA LNAPL Pulsed Biopsarge Pilot Test
WELL ID
PB-­‐IW-­‐1P
PB-­‐IW-­‐1P2
PB-­‐IW-­‐3P
PB-­‐IW-­‐3P2
PB-­‐MW-­‐1P
PB-­‐MW-­‐1P2
PB-­‐MW-­‐2P
PB-­‐MW-­‐2P2
DTP (BTOC)
ND
16.08
ND
15.9
ND
18.5
ND
18.54
DTW (BTOC)
15.25
43.4
15.07
42.65
17.19
40.28
17.45
45.61
Pre Development
DTP (BGS)
DTW (BGS)
ND
14.8
15.6
42.9
ND
14.6
15.4
42.1
ND
14.2
15.5
37.3
ND
14.5
15.5
42.6
LNAPL Tkns
NA
27.3
NA
26.8
NA
21.8
NA
27.1
SCREEN INTERVAL (BGS)
22-­‐24
42-­‐44
22-­‐24
42-­‐44
21-­‐24
40-­‐43
21-­‐24
41-­‐44
WELL ID
PB-­‐IW-­‐1P
PB-­‐IW-­‐1P2
PB-­‐IW-­‐3P
PB-­‐IW-­‐3P2
PB-­‐MW-­‐1P
PB-­‐MW-­‐1P2
PB-­‐MW-­‐2P
PB-­‐MW-­‐2P2
DTP (BTOC)
ND
16.43
ND
16.42
ND
18.26
ND
18.78
9/12/2011 (Post Development)
DTW (BTOC)
DTP (BGS)
DTW (BGS)
15.34
ND
14.8
43.78
15.9
43.3
15.13
ND
14.6
37.5
15.9
37
17.22
ND
14.22
46.36
15.26
43.4
17.58
ND
14.6
32.58
15.8
29.6
LNAPL Tkns
NA
27.4
NA
21.1
NA
28.1
NA
13.8
SCREEN INTERVAL (BGS)
22-­‐24
42-­‐44
22-­‐24
42-­‐44
21-­‐24
40-­‐43
21-­‐24
41-­‐44
10/6/11
DTP (BGS)
DTW (BGS)
ND
14.9
15.9
45.9
ND
14.6
15.9
40.2
ND
14.3
15.3
43.4
ND
14 .6
15.8
32.4
LNAPL Tkns
NA
30.0
NA
24.3
NA
28.1
NA
16.6
SCREEN INTERVAL (BGS)
22-­‐24
42-­‐44
22-­‐24
42-­‐44
21-­‐24
40-­‐43
21-­‐24
41-­‐44
WELL ID
DTP (BTOC) DTW (BTOC)
PB-­‐IW-­‐1P
ND
15.35
PB-­‐IW-­‐1P2
16.43
46.41
PB-­‐IW-­‐3P
ND
15.13
PB-­‐IW-­‐3P2
16.44
40.74
PB-­‐MW-­‐1P
ND
17.25
PB-­‐MW-­‐1P2
18.28
46.41
PB-­‐MW-­‐2P
ND
17.56
PB-­‐MW-­‐2P2
18.78
35.41
DTP= Depth to product
DTW=Depth to water
ND=Not Detected
BGS=Below Ground Surface (approximate)
NA=Not Applicable
All measurements/thicknesses in feet
LNAPL Tkns Incr 9/12/11 to 10/6/11
2.6
3.2
0.0
2.8
GSI Job: G-3195-102
Issued: October 2015
Page 1 of 4
GROUNDWATER MONITORING RESULTS
Pulsed Biosparge System
LA LNAPL - Shell Carson Terminal
Non DATA ‐ Assume:
0.1 ug:
Injection wells
Monitoring wells inside treatment area
Monitoring wells outside treatment area
GW Benzene Concentration (μg/L)
Well
Operation Time (months)
PB‐IW‐1‐P
PB‐IW‐2‐P
PB‐IW‐3‐P
PB‐MW‐1‐P
PB‐MW‐2‐P
PB‐MW‐3‐P
PB‐MW‐4‐P
PB‐MW‐5‐P
PB‐MW‐6‐P
PB‐MW‐7‐P
‐2
1
2
4
6
8.5
11
14
30
170
220
200
20
61
6
2
2
5
6,300
1,100
2,600
2,400
330
110
260
505
150
470
150
150
110
280
4
580
310
450
705
340
250
320
260
220
460
320
430
330
180
16
110
250
650
190
140
190
240
290
220
170
12,000
510
520
530
600
490
380
380
510
440
810
830
780
970
530
590
560
840
750
14,000
91
15,000
260
GW Toluene Concentration (μg/L)
Well
Operation Time (months)
PB‐IW‐1‐P
PB‐IW‐2‐P
PB‐IW‐3‐P
PB‐MW‐1‐P
PB‐MW‐2‐P
PB‐MW‐3‐P
PB‐MW‐4‐P
PB‐MW‐5‐P
PB‐MW‐6‐P
PB‐MW‐7‐P
‐2
1
2
4
6
8.5
11
14
30
190
160
190
20
87
4
2
3
3
1,700
410
745
390
84
29
47
250
29
950
530
280
160
600
150
310
690
250
150
290
180
82
620
460
600
450
200
50
130
340
580
280
210
310
420
440
370
290
3,100
91
53
97
110
160
45
55
79
74
775
790
830
1,100
460
620
580
940
780
2,000
14
40
4,300
290
GW Xylenes Concentration (μg/L)
Well
Operation Time (months)
PB‐IW‐1‐P
PB‐IW‐2‐P
PB‐IW‐3‐P
PB‐MW‐1‐P
PB‐MW‐2‐P
PB‐MW‐3‐P
PB‐MW‐4‐P
PB‐MW‐5‐P
PB‐MW‐6‐P
PB‐MW‐7‐P
‐2
1
2
4
6
8.5
11
14
30
340
230
260
130
150
34
30
13
14
1,300
880
705
510
170
52
98
970
200
1,200
600
420
440
550
80
530
340
390
670
280
280
340
350
260
520
390
450
400
200
120
210
400
590
320
240
270
330
320
340
330
2,300
270
140
180
170
230
80
110
140
160
830
670
780
940
410
520
570
840
700
1,600
‐
280
4,900
390
GSI Job: G-3195-102
Issued: October 2015
Page 2 of 4
GROUNDWATER MONITORING RESULTS
Pulsed Biosparge System
LA LNAPL - Shell Carson Terminal
Non DATA ‐ Assume:
0.1 ug:
Injection wells
Monitoring wells inside treatment area
Monitoring wells outside treatment area
GW Total Diesel Range Organics (DRO) Concentration (μg/L)
Well
Operation Time (months)
PB‐IW‐1‐P
PB‐IW‐2‐P
PB‐IW‐3‐P
PB‐MW‐1‐P
PB‐MW‐2‐P
PB‐MW‐3‐P
PB‐MW‐4‐P
PB‐MW‐5‐P
PB‐MW‐6‐P
PB‐MW‐7‐P
‐2
1
2
4
6
8.5
11
14
30
20,000
15,000
13,000
12,000
14,000
16,000
12,000
11,000
13,000
17,000
34,000
18,500
19,000
52,000
22,000
20,000
38,000
41,000
55,000
41,000
28,000
24,000
27,000
19,000
75,000
89,000
34,000
63,500
41,000
27,000
54,000
21,000
11,000
37,000
22,000
21,000
15,000
15,000
8,100
11,000
13,000
28,000
17,000
15,000
13,000
15,000
15,000
20,000
20,000
27,000
38,000
33,000
23,000
24,000
28,000
26,000
24,000
23,000
20,000
10,500
9,700
8,700
8,800
11,000
10,000
12,000
9,400
13,000
33,000
PB‐MW‐5‐P
47,100
43,500
31,300
31,400
37,600
33,600
31,900
32,300
26,700
PB‐MW‐6‐P
23,700
26,400
20,800
20,000
21,900
23,700
23,200
19,500
23,700
PB‐MW‐7‐P
94,000
Operation Time (months)
‐2
1
2
4
6
8.5
11
14
30
PB‐IW‐1‐P
28,400
21,900
19,000
15,020
20,400
22,440
16,500
15,480
17,190
PB‐IW‐2‐P
47,500
58,500
35,000
29,800
69,500
32,800
28,000
85,500
53,800
75,000
PB‐IW‐3‐P
75,300
51,900
35,400
29,300
35,700
24,900
104,000
4,000
22,000
GW Total Petroleum Hydrocarbons (TPH ALL) Concentration (μg/L)
Well
PB‐MW‐1‐P
PB‐MW‐2‐P
PB‐MW‐3‐P
PB‐MW‐4‐P
88,000
49,100
24,200
87,000
100,200
32,400
21,800
43,100
29,700
19,300
75,750
21,500
21,800
50,500
22,000
23,100
34,100
12,150
29,300
62,700
16,000
27,600
28,600
18,200
96,000
16,200
37,900
30,300
GSI Job: G-3195-102
Issued: October 2015
Page 3 of 4
GROUNDWATER MONITORING RESULTS
Pulsed Biosparge System
LA LNAPL - Shell Carson Terminal
Non DATA ‐ Assume:
0.1 ug:
Injection wells
Monitoring wells inside treatment area
Monitoring wells outside treatment area
GW BTEX Concentration (μg/L)
Well
Operation Time (months)
PB‐IW‐1‐P
PB‐IW‐2‐P
PB‐IW‐3‐P
PB‐MW‐1‐P
PB‐MW‐2‐P
PB‐MW‐3‐P
PB‐MW‐4‐P
PB‐MW‐5‐P
PB‐MW‐6‐P
PB‐MW‐7‐P
‐2
1
2
4
6
8.5
11
14
30
768
657
699
172
319
49
35
20
26
9,368
2,406
4,083
3,314
592
195
424
1,802
386
2,850
1,352
872
736
889
104
1,880
839
1,260
2,315
963
764
1,046
890
641
1,730
1,226
1,580
1,255
611
191
477
1,063
1,940
822
622
829
1,075
1,149
1,010
862
17,760
971
923
1,037
1,190
1,080
695
755
1,019
834
2,448
2,373
2,489
3,170
1,470
1,818
1,763
2,740
2,308
17,639
439
24,970
942
GW Ethylbenzene Concentration (μg/L)
Well
Operation Time (months)
PB‐IW‐1‐P
PB‐IW‐2‐P
PB‐IW‐3‐P
PB‐MW‐1‐P
PB‐MW‐2‐P
PB‐MW‐3‐P
PB‐MW‐4‐P
PB‐MW‐5‐P
PB‐MW‐6‐P
PB‐MW‐7‐P
‐2
1
2
4
6
8.5
11
14
30
68
47
49
2
21
4
1
2
4
68
16
33
14
8
4
19
77
7
230
72
22
26
59
6
170
39
110
250
93
84
96
100
79
130
56
100
75
31
5
27
73
120
32
32
59
85
99
80
72
‐
2
360
100
210
230
310
200
190
210
290
160
33
83
99
160
70
88
53
120
78
39
28
770
GW Total Petroleum Hydrocarbons (TPH MOTOR) Concentration (μg/L)
Well
Operation Time (months)
PB‐IW‐1‐P
PB‐IW‐2‐P
PB‐IW‐3‐P
PB‐MW‐1‐P
PB‐MW‐2‐P
PB‐MW‐3‐P
PB‐MW‐4‐P
PB‐MW‐5‐P
PB‐MW‐6‐P
PB‐MW‐7‐P
‐2
1
2
4
6
8.5
11
14
30
4,500
3,300
2,900
2,300
4,400
5,700
3,700
3,800
3,500
3,500
9,500
5,000
4,000
14,000
9,100
5,300
9,500
8,700
4,300
4,000
3,400
2,100
3,100
4,700
3,400
4,400
2,800
3,550
3,800
3,800
3,100
2,600
1,800
3,300
2,800
2,500
2,100
3,800
2,000
2,000
3,000
2,900
3,000
2,600
2,900
2,600
3,400
5,400
3,800
10,000
2,700
2,800
2,500
2,700
3,600
3,300
2,600
2,700
2,300
2,850
2,700
2,900
2,400
3,800
3,700
3,300
2,700
3,000
12,000
15,000
11,000
3,600
GSI Job: G-3195-102
Issued: October 2015
Page 4 of 4
GROUNDWATER MONITORING RESULTS
Pulsed Biosparge System
LA LNAPL - Shell Carson Terminal
Non DATA ‐ Assume:
0.1 ug:
Injection wells
Monitoring wells inside treatment area
Monitoring wells outside treatment area
GW Total Gasoline Range Organics (GRO) Concentration (μg/L)
Well
Operation Time (months)
PB‐IW‐1‐P
PB‐IW‐2‐P
PB‐IW‐3‐P
PB‐MW‐1‐P
PB‐MW‐2‐P
PB‐MW‐3‐P
PB‐MW‐4‐P
PB‐MW‐5‐P
PB‐MW‐6‐P
PB‐MW‐7‐P
‐2
1
2
4
6
8.5
11
14
30
3,900
3,600
3,100
720
2,000
740
800
680
690
27,000
15,000
11,500
6,800
3,500
1,700
2,700
38,000
4,100
16,000
6,900
4,000
3,200
5,600
1,200
9,600
6,800
6,300
8,700
5,700
3,300
5,600
5,000
3,400
8,800
7,600
6,200
4,400
3,200
2,050
3,000
2,200
7,000
4,200
4,200
3,400
4,200
4,700
3,900
3,800
50,000
6,400
7,700
5,800
4,700
6,000
4,300
5,300
6,600
4,400
10,350
14,000
9,200
8,800
7,100
10,000
7,900
7,400
7,700
49,000
PB‐MW‐5‐P
610
560
480
590
480
490
370
470
210
PB‐MW‐6‐P
5.3
6.7
5.7
7.5
21.0
6.9
4.0
7.4
9.0
PB‐MW‐7‐P
8,100
Operation Time (months)
‐2
1
2
4
6
8.5
11
14
30
PB‐IW‐1‐P
120
170
140
96
110
96
70
61
30
PB‐IW‐2‐P
600
530
725
670
210
43
130
190
110
14,000
PB‐IW‐3‐P
330
330
210
220
100
26
110
PB‐MW‐1‐P
1,100
600
660
1,200
550
320
560
320
110
81,000
4,700
GW DIPE Concentration (μg/L)
Well
PB‐MW‐2‐P
PB‐MW‐3‐P
310
120
360
110
350
95
320
110
210
130
145
98
120
72
210
270
120
PB‐MW‐4‐P
7,500
10,000
GSI Job: G-­‐3195-­‐102
Issued: 8 August 2014
Page 1 of 1
GROUNDWATER MONITORING RESULTS (DISSOLVED OXYGEN)
Pulsed Biosparge System
LA LNAPL - Shell Carson Terminal
INJECTION WELLS
Date
6-­‐Apr-­‐12
3-­‐Jul-­‐12
2-­‐Aug-­‐12
3-­‐Oct-­‐12
7-­‐Dec-­‐12
22-­‐Feb-­‐13
6-­‐May-­‐13
2-­‐Mar-­‐13
2-­‐Jun-­‐13
PB-­‐IW-­‐1-­‐P (DO)
Months of System Operation
-­‐2
1
2
4
6
9
11
14
17
DO
(mg/L)
0.06
0.45
0.17
1.1
9.98
12.6
15
Date
6-­‐Apr-­‐12
3-­‐Jul-­‐12
2-­‐Aug-­‐12
3-­‐Oct-­‐12
7-­‐Dec-­‐12
22-­‐Feb-­‐13
6-­‐May-­‐13
2-­‐Mar-­‐13
2-­‐Jun-­‐13
PB-­‐IW-­‐2-­‐P (DO)
Months of System Operation
-­‐2
1
2
4
6
9
11
14
17
DO
(mg/L)
0.20
0.70
0.52
3.59
11.92
0.63
0
Date
6-­‐Apr-­‐12
3-­‐Jul-­‐12
2-­‐Aug-­‐12
3-­‐Oct-­‐12
7-­‐Dec-­‐12
22-­‐Feb-­‐13
6-­‐May-­‐13
2-­‐Mar-­‐13
2-­‐Jun-­‐13
PB-­‐IW-­‐3-­‐P (DO)
Months of System Operation
-­‐2
1
2
4
6
9
11
14
17
DO
(mg/L)
0.10
0.99
6.86
0.75
0.82
1.57
Injection wells
Monitoring wells inside treatment area
Monitoring wells outside treatment area
MONITORING WELLS
Date
6-­‐Apr-­‐12
3-­‐Jul-­‐12
2-­‐Aug-­‐12
3-­‐Oct-­‐12
7-­‐Dec-­‐12
22-­‐Feb-­‐13
6-­‐May-­‐13
2-­‐Mar-­‐13
2-­‐Jun-­‐13
Date
6-­‐Apr-­‐12
3-­‐Jul-­‐12
2-­‐Aug-­‐12
3-­‐Oct-­‐12
7-­‐Dec-­‐12
22-­‐Feb-­‐13
6-­‐May-­‐13
2-­‐Mar-­‐13
2-­‐Jun-­‐13
PB-­‐MW-­‐1-­‐P (DO)
Months of System Operation
-­‐2
1
2
4
6
9
11
14
17
PB-­‐MW-­‐4-­‐P (DO)
Months of System Operation
-­‐2
1
2
4
6
9
11
14
17
DO
(mg/L)
Date
6-­‐Apr-­‐12
3-­‐Jul-­‐12
2-­‐Aug-­‐12
3-­‐Oct-­‐12
7-­‐Dec-­‐12
22-­‐Feb-­‐13
6-­‐May-­‐13
2-­‐Mar-­‐13
2-­‐Jun-­‐13
DO
(mg/L)
0.23
Date
6-­‐Apr-­‐12
3-­‐Jul-­‐12
2-­‐Aug-­‐12
3-­‐Oct-­‐12
7-­‐Dec-­‐12
22-­‐Feb-­‐13
6-­‐May-­‐13
2-­‐Mar-­‐13
2-­‐Jun-­‐13
PB-­‐MW-­‐2-­‐P (DO)
Months of System Operation
-­‐2
1
2
4
6
9
11
14
17
PB-­‐MW-­‐5-­‐P (DO)
Months of System Operation
-­‐2
1
2
4
6
9
11
14
17
DO
(mg/L)
Date
6-­‐Apr-­‐12
3-­‐Jul-­‐12
2-­‐Aug-­‐12
3-­‐Oct-­‐12
7-­‐Dec-­‐12
22-­‐Feb-­‐13
6-­‐May-­‐13
2-­‐Mar-­‐13
2-­‐Jun-­‐13
DO
(mg/L)
Date
6-­‐Apr-­‐12
3-­‐Jul-­‐12
2-­‐Aug-­‐12
3-­‐Oct-­‐12
7-­‐Dec-­‐12
22-­‐Feb-­‐13
6-­‐May-­‐13
2-­‐Mar-­‐13
2-­‐Jun-­‐13
PB-­‐MW-­‐3-­‐P (DO)
Months of System Operation
-­‐2
1
2
4
6
9
11
14
17
PB-­‐MW-­‐6-­‐P (DO)
Months of System Operation
-­‐2
1
2
4
6
9
11
14
17
DO
(mg/L)
DO
(mg/L)
Date
6-­‐Apr-­‐12
3-­‐Jul-­‐12
2-­‐Aug-­‐12
3-­‐Oct-­‐12
7-­‐Dec-­‐12
22-­‐Feb-­‐13
6-­‐May-­‐13
2-­‐Mar-­‐13
2-­‐Jun-­‐13
PB-­‐MW-­‐7-­‐P (DO)
Months of System Operation
-­‐2
1
2
4
6
9
11
14
17
DO
(mg/L)
0.39
GSI Job No. G-­‐3195
Issued: 8 August 2014
Page 1 of 1
PRELIMINARY
BEFORE AND AFTER SOIL RESULTS
Pulsed Biosparge System
LA LNAPL -­‐ Shell Carson Terminal
Summary Statistics
Pre-­‐Test
Post-­‐Test
% Reduction
Pre-­‐Test
Post-­‐Test
% Reduction
Pre-­‐Test
Post-­‐Test
% Reduction
Pre-­‐Test
Post-­‐Test
% Reduction
Average Soil Concentrations (mg/kg): PB-­‐MW-­‐1
Ben
BTEX
TPH
GRO
DRO
1.2
29
5,265
2,501
2,711
8,348
3,461
4,737
0.7
34.8
47%
-­‐20%
-­‐59%
-­‐38%
-­‐75%
Geomean Soil Concentrations (mg/kg): PB-­‐MW-­‐1
Ben
BTEX
TPH
GRO
DRO
0.79
17
2,555
1,139
1,319
0.56
18.6
3,987
1,560
2,334
29%
-­‐10%
-­‐56%
-­‐37%
-­‐77%
Average Soil Concentrations (mg/kg): PB-­‐MW-­‐3P
Ben
BTEX
TPH
GRO
DRO
0.4
14
3,600
1,619
1,930
0.4
17
6,800
3,105
3,630
5%
-­‐19%
-­‐89%
-­‐92%
-­‐88%
Geomean Soil Concentrations (mg/kg): PB-­‐MW-­‐3P
Ben
BTEX
TPH
GRO
DRO
0.3
11
3,523
1,608
1,767
0.3
12.4
6,644
3,060
3,514
1%
-­‐13%
-­‐89%
-­‐90%
-­‐99%
DIPE
0.39
0.00
100%
DIPE
0.028
0.001
96%
DIPE
0.001
0.001
0%
DIPE
0.00
0.00
0%
Pre-­‐Test
Post-­‐Test
% Reduction
Pre-­‐Test
Post-­‐Test
% Reduction
Pre-­‐Test
Post-­‐Test
% Reduction
Pre-­‐Test
Post-­‐Test
% Reduction
Average Soil Concentrations (mg/kg): PB-­‐MW-­‐2
Ben
BTEX
TPH
GRO
DRO
0.8
40
3,600
1,619
1,930
10,767
5,164
3,630
0.8
46
-­‐2%
-­‐16%
-­‐199%
-­‐219%
-­‐88%
Geomean Soil Concentrations (mg/kg): PB-­‐MW-­‐2
Ben
BTEX
TPH
GRO
DRO
0.3
11
3,523
1,608
1,767
0.7
34.8
7,542
3,464
3,974
-­‐102%
-­‐218%
-­‐114%
-­‐115%
-­‐125%
Average Soil Concentrations (mg/kg): PB-­‐MW-­‐4
Ben
BTEX
TPH
GRO
DRO
36.7
278
2,733
1,763
853
33.0
272
11,867
7,580
4,124
10%
2%
-­‐334%
-­‐330%
-­‐384%
Geomean Soil Concentrations (mg/kg): PB-­‐M@-­‐4
Ben
BTEX
TPH
GRO
DRO
8.7
57
2,638
1,620
838
4.7
60.2
6,304
4,274
1,857
47%
-­‐6%
-­‐139%
-­‐164%
-­‐122%
DIPE
0.00
0.00
0%
DIPE
0.00
0.00
0%
DIPE
7.667
7.267
5%
DIPE
0.51
0.49
5%
BEFORE AND AFTER SOIL RESULTS
Pulsed Biosparge System
LA LNAPL -­‐ Shell Carson Terminal
GSI Job No. G-­‐3195
Issued: 8 August 2014
Page 1 of 1
PRELIMINARY
Original Data
LOCATION NAME
SAMPLE DATE
SAMPLE DEPTH
Benzene
Diisopropyl Ether (DIPE)
Ethylbenzene
Naphthalene
Toluene
Xylenes,Total
Carbon Chain C6
Carbon Chain C7
Carbon Chain C8
Carbon Chain C9-C10
Carbon Chain C11-C12
Carbon Chain C13-C14
Carbon Chain C15-C16
Carbon Chain C17-C18
Carbon Chain C19-C20
Carbon Chain C21-C22
Carbon Chain C23-C24
Carbon Chain C25-C28
Carbon Chain C29-C32
Carbon Chain C33-C36
Total Petroleum Hydroc.s (C6-C44)
TPH as Gasoline (C6-C12)
Diesel Range Organics (C13 to C28)
TPH as Motor Oil (C29 to 3)
LOCATION NAME
SAMPLE DATE
SAMPLE DEPTH
Benzene
Diisopropyl Ether (DIPE)
Ethylbenzene
Naphthalene
Toluene
Xylenes,Total
Carbon Chain C6
Carbon Chain C7
Carbon Chain C8
Carbon Chain C9-C10
Carbon Chain C11-C12
Carbon Chain C13-C14
Carbon Chain C15-C16
Carbon Chain C17-C18
Carbon Chain C19-C20
Carbon Chain C21-C22
Carbon Chain C23-C24
Carbon Chain C25-C28
Carbon Chain C29-C32
Carbon Chain C33-C36
Total Petroleum Hydroc.s (C6-C44)
TPH as Gasoline (C6-C12)
Diesel Range Organics (C13 to C28)
TPH as Motor Oil (C29 to 3)
Units
ug/kg
ug/kg
ug/kg
ug/kg
ug/kg
ug/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
Units
ug/kg
ug/kg
ug/kg
ug/kg
ug/kg
ug/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
PB-MW-1
10/26/11
21.3
97
< 51
790
760
< 51
650
< 15
< 15
< 15
23
47
51
24
< 15
< 15
< 15
< 15
< 15
< 15
< 15
160
NA
NA
NA
PB-MW-1
10/26/11
22.4
1,500
< 200
12,000
19,000
4,600
30,000
< 75
320
510
2,000
3,000
2,900
1,000
650
290
200
99
< 75
< 75
< 75
11,000
NA
NA
NA
PB-MW-1
10/26/11
23.2
1,500
620
7,500
14,000
5,700
20,000
< 25
66
110
680
1,500
1,200
740
410
290
220
140
87
66
27
5,500
NA
NA
NA
PB-MW-1
10/26/11
24.2
1,800
930
8,500
6,300
6,700
15,000
< 25
29
80
440
1,200
1,000
610
340
240
180
100
71
59
28
4,400
NA
NA
NA
PB-MW-2
10/26/11
21
< 940
< 940
8,700
19,000
9,900
20,000
< 25
31
72
570
1,200
1,200
430
270
77
67
< 25
< 25
< 25
< 25
3,900
NA
NA
NA
PB-MW-2
10/26/11
22.1
1,000
< 430
8,000
20,000
8,900
23,000
< 100
170
330
1,700
3,100
2,800
990
650
280
190
< 100
< 100
< 100
< 100
10,000
NA
NA
NA
PB-MW-2
10/26/11
22.9
1,000
< 410
7,000
19,000
8,900
22,000
< 120
260
410
2,200
3,600
3,500
1,200
810
370
230
< 120
< 120
< 120
< 120
13,000
NA
NA
NA
PB-MW-2
10/26/11
23.6
NA
NA
NA
NA
NA
NA
< 100
170
300
1,600
2,800
2,600
920
620
310
210
100
< 100
< 100
< 100
9,600
NA
NA
NA
PB-MW-3P
7/11/12
16.7
< 440
< 440
640
12,000
700
3,400
< 25
< 25
< 25
280
1,200
1,500
620
550
140
130
92
92
29
< 25
4,700
NA
NA
NA
PB-MW-3P
7/11/12
20.4
< 420
< 420
2,000
< 4200
1,700
5,300
< 25
< 25
44
350
1,100
620
300
220
140
74
43
39
43
< 25
3,000
NA
NA
NA
PB-MW-3P
7/11/12
25.3
730
< 430
5,800
13,000
6,100
16,000
< 25
< 25
82
500
1,300
630
270
170
88
41
30
< 25
< 25
< 25
3,100
NA
NA
NA
PB-MW-4P
7/11/12
17.9
< 450
< 450
< 450
< 4500
< 450
< 900
< 25
< 25
10
220
700
560
200
77
31
18
< 25
< 25
< 25
< 25
1,800
NA
NA
NA
PB-MW-4P
7/11/12
22.5
64,000
12,000
29,000
30,000
59,000
160,000
< 25
< 25
150
500
1,100
510
340
170
< 25
< 25
< 25
< 25
< 25
< 25
3,000
NA
NA
NA
PB-MW-1
10/10/13
21.3
120
< 39
1,100
1,800
120
2,000
< 5.0
< 5.0
9
45
180
190
81
42
22
11
7
< 5.0
< 5.0
< 5.0
590
NA
NA
NA
PB-MW-1
10/10/13
22.5
840
< 410
9,500
22,000
4,300
25,000
< 100
190
310
1,600
4,000
3,600
1,600
1,000
480
330
160
100
< 100
< 100
14,000
NA
NA
NA
PB-MW-1
10/10/13
23.2
1,200
< 480
8,900
20,000
7,600
27,000
< 100
210
500
2,000
4,200
4,500
2,200
1,600
830
550
290
220
150
< 100
17,000
NA
NA
NA
PB-MW-1
10/10/13
24.2
820
< 400
4,700
12,000
2,900
12,000
< 50
< 50
< 50
140
460
490
270
200
110
67
< 50
< 50
< 50
< 50
1,800
NA
NA
NA
PB-MW-2
10/10/13
21
< 460
< 460
1,100
4,700
1,100
8,000
< 50
< 50
< 50
260
810
760
330
190
65
< 50
< 50
< 50
< 50
< 50
2,500
NA
NA
NA
PB-MW-2
10/10/13
21.9
800
< 420
13,000
35,000
10,000
40,000
< 250
270
970
2,700
6,900
6,000
2,600
1,600
730
350
< 250
< 250
< 250
< 250
22,000
NA
NA
NA
PB-MW-2
10/10/13
24.2
1,500
< 520
11,000
26,000
12,000
39,000
< 50
83
200
900
2,400
2,200
940
570
230
140
57
< 50
< 50
< 50
7,800
NA
NA
NA
PB-MW-3
10/10/13
18.2
< 430
< 430
1,800
11,000
< 430
3,800
< 50
< 50
110
630
2,300
2,100
860
500
160
97
< 50
< 50
< 50
< 50
6,900
NA
NA
NA
PB-MW-3
10/10/13
20.4
< 470
< 470
1,800
6,000
900
5,700
< 50
< 50
110
870
2,800
2,600
1,100
610
220
96
53
< 50
< 50
< 50
8,500
NA
NA
NA
PB-MW-3
10/10/13
25.3
650
< 250
7,100
19,000
5,700
23,000
< 50
54
140
700
1,600
1,400
580
330
130
54
< 50
< 50
< 50
< 50
5,000
NA
NA
NA
PB-MW-4
10/10/13
17.9
< 86
< 86
370
5,000
130
790
< 50
< 50
< 50
220
920
390
170
71
< 50
< 50
< 50
< 50
< 50
< 50
1,800
NA
NA
NA
PB-MW-4
10/10/13
22.5
60,000
13,000
48,000
55,000
73,000
280,000
840
1,200
2,600
5,900
7,200
6,000
2,500
1,600
700
< 500
< 500
< 500
< 500
< 500
29,000
NA
NA
NA
PB-MW-4
10/10/13
25.7
39,000
8,800
35,000
32,000
61,000
220,000
220
350
690
1,500
1,100
520
250
92
78
< 50
< 50
< 50
< 50
< 50
4,800
NA
NA
NA
PB-MW-4P
7/11/12
25.7
46,000
11,000
51,000
< 46000
95,000
330,000
< 25
100
410
1,100
1,000
310
140
110
60
32
< 25
< 25
< 25
< 25
3,400
NA
NA
NA