remediation evaluation at site st 14 jba

Michael H. Flinn, Ph.D., PMP

Remediation Evaluation of Site ST-14Joint Base Andrews:

A Detective Story (Part 1)

IntroductionRestoration Branch of Air Force Center for Engineering and the

Environment Technical Division (AFCEE/TDV) performed an

Environmental Restoration Program – Optimization (ERP-O) visit at

Joint Base Andrews Naval Air Facility Washington (JBA)

ERP-O Team recommended that the Site ST-14 remedy be reviewed

– Evaluate for effectiveness

– Recommend a path forward

Conducting the evaluation was like reading a detective story. The

available documentation had several red herrings and false leads.

Multiple lines of evidence (clues) had to be pieced together to reach a

full understanding of the site situation.

Introduction (Concluded)

I have no data yet. It is a capital mistake to

theorise [sic] before one has data. Insensibly one

begins to twist facts to suit theories, instead of

theories to suit facts.

Sherlock Holmes in “A Scandal in Bohemia” by Sir

Arthur Conan Doyle

The Scene - Joint Base Andrews

Formerly known as

Andrews Air Force

Base

Located southeast

of Washington, D.C.

JBA

The Scene - Site ST-14 (Continued)

Location of the former East

Side Service Station

Two 10,000 gallon USTs

removed in 1983

Approximately 20,000 gallons

of gasoline recovered

Other contaminant sources

include aircraft and vehicle

washracksDraft ST-14 Second Long-Term Monitoring Report, Andrews Air Force Base. June 2010

The Scene – Hydrogeology (Continued)Unconfined aquifer comprised of three stratigraphic lithologies of the

Brandywine Formation Upland Deposits

– Shallow: clayey, gravelly silt (range 0 – 28’ bgs, avg. 14’ bgs)

– Intermediate: sand and gravel (range 10 – 38’ bgs, avg. 26’ bgs)

– Deep: silty fine sand (range 15 – 40’ bgs, avg. 33’ bgs)

Average depth to water is 17’ bgs

Estimates of Intermediate K range from 0.24 – 3.5’ per day

Hydraulic gradient = 0.007 – 0.02

Underlain by Calvert Formation (range 38 – 40’ bgs, outcrops at northeast)

– Described as a regional aquitard (Final ST-14 Feasibility Study Report, January 2007)

The Scene - Hydrogeology (Concluded)

Derived from Draft ST-14 Second Long-Term Monitoring Report, Andrews Air Force Base. June 2010

The Suspects – TCE, BTEX, CCl4 (2006)

62 Acre TCE Plume

5.5 Acre CCl4 Plume 6.4 Acre BTEX Plume


The Tools: TCE and CCl4 Remediation –Reductive Dechlorination

Sodium lactate (6% solution) injected to promote reductive dechlorination

– Ten injection events between October 2007 and November 2009

– Ten injection “barriers”

– 210 injection points (max. 45’ bgs)

– Total of 239,250 gallons of sodium lactate solution injected

Emulsified vegetable oil (EOS®)

– One injection event between May and June 2010

– 250 gallons of 4-6% EOS injected per injection point

– Total of 25,000 gallons of EOS added

The Tools: BTEX Remediation -Aerobic Respiration

PermeOx® Plus injections

120 pounds of PermeOx® Plus in 120 gallons of water per point

One foot increments from 32’ to 19’ bgs

First: October 2007 (40 points, 4,800 lbs PermeOx® Plus)

Second: July 2009 (10 points, 1,200 lbs PermeOx® Plus)

Third: May 2010 (8 points, 960 lbs PermeOx® Plus)

Total = 6,960 lbs

Injection Event 1 Locations (OCT 2007)

4,800 pounds of

PermeOx® Plus

49,500 gallons of

Sodium Lactate

1

2

3

4

5

67


Injection Event 2 Locations (DEC 2007 – JAN 2008)

47,000 gallons of

Sodium Lactate

1

2

3

45

6

7


Injection Event 3 Locations (FEB 2008 – MAR 2008)

45,500 gallons of

Sodium Lactate

1

2

3

5

6

4

7


6

Injection Event 4 Locations(APR 2008 – MAY 2008)

33,000 gallons of

Sodium Lactate

1

2

3

45

67


Injection Event 5 Locations (JUL 2008)

30,750 gallons of

Sodium Lactate

1 2

3

45

6

7


Injection Event 6 Locations (NOV 2008)

19,000 gallons of

Sodium Lactate

1

2

3

45

6

7


Injection Event 7 Locations (JUN 2009)

3,000 gallons of

Sodium Lactate

1

2

3

4

5

6

7


Injection Event 8 Locations (JUL 2009)

3,500 gallons of

Sodium Lactate

1,200 pounds of

PermeOx® Plus

1

2

3

4

5

67

89

10


Injection Event 9 Locations (SEP 2009)

5,000 gallons of

Sodium Lactate

1

2

3

4

5

6 7

8

9

10


Injection Event 10 Locations (NOV 2009)

3,000 gallons of

Sodium Lactate

1

2

3

45

67

8

9

10


Injection Event 11 Locations (MAY - JUN 2010)

960 pounds of

PermeOx® Plus

25,000 gallons

of EOS®

1

2

3

4

5

6

7

10


9

8

Contractor’s Conclusion

The groundwater analytical data and geochemical

parameters at Site ST-14 suggest that the remedial actions

performed at the site, including the PermeOx® Plus and

sodium lactate injections, generated favorable conditions in

the treatment area conducive to the biodegradation of the

primary [contaminants of concern].

And,

The data collected during the second long term monitoring

event showed that the remedial actions implemented at ST-

14 have had positive results in most of the targeted areas.

Evidence of Success?

The contractor cited the following lines of

evidence to demonstrate the success of the

injections:

–Mann-Kendall analysis

–Trend analysis

–Reductions in contaminant concentrations

–Phospholipid Fatty Acid (PLFA) analysis for percent biomass

–Reductions in plume size

Clues from Mann Kendall and Trend Analyses

Mann Kendall analysis were conducted using the

Monitoring and Remediation Optimization System

(MAROS) software to identify general trends

(increasing, decreasing, stable, no trend)

Regression analyses were conducted on

selected wells to predict when contaminants

would meet maximum contaminant limits (MCLs)

TCE Regression Analysis (Red Herrings)

Clues from Injection Barrier Monitoring Well Data

Injection Barrier Wells

– Injection Barrier 1: Monitor Well (MW) 17

– Injection Barrier 3: MW 11

– Injection Barrier 5: MW 12 and MW 19 (well pair)

– Injection Barrier 6: MW 23 and MW 24 (well pair)

Downgradient Monitoring Wells

– MW 16

– MW 37

– MW 07

Injection Barrier 1 - MW 17 Data (Evidence of Incomplete Degradation)


Injection Barrier 3 - MW 11 Data(Evidence of Incomplete Degradation)


Injection Barrier 5 - MWs 12 (Deep?) and 19 (Shallow) Data (Evidence of Incomplete Degradation)


Injection Barrier 6 - MWs 23 (Deep) and 24 (Shallow?) Data (Evidence of Incomplete Degradation)


Downgradient Wells - MWs 16 and 37 Data(Evidence of Displacement)


Similar Response

Pattern

Downgradient Wells – MW 07 Data (Smoking Gun for Displacement)


4,8

00 lb

s

1,2

00 lb

s

PermeOx

Mounding

Sample DO Concentrations

Calvert Formation a Regional Aquitard? (False Lead)



Boring logs

indicate that

Calvert

Formation in

area of Site

ST-14

consists of

sandy clay


The Calvert is a silty clay with local sand beds. It is reported to be

a poor aquifer and considered to be a confining bed in southern

Maryland (Chapelle and Drummond, 1983). Locally, it may yield

small amounts of water to farm or domestic wells. Recharge to the

Calvert is probably transmitted from overlying units and discharge

is likely directed either to local surface waters or to water-bearing

units at greater depth. Water in the Calvert may exist under water

table or artesian (confined) conditions [emphasis added].

“Installation Restoration Program Phase I Records Search” (June

1985)

Clues from Changes in Plume Size (MAR 2006)

Draft ST-14 Second Long-Term Monitoring Report, Andrews Air Force Base. June 2010

Clues from Changes in Plume Size (APR 2008)


Clues from Changes in Plume Size (JUL 2008)


Clues from Changes in Plume Size (OCT 2008)


Clues from Changes in Plume Size (JAN 2009)



Letter to Maryland Department of Environmental Quality, 2011

Michael H. Flinn, Ph.D., PMP

Remediation Evaluation of Site ST-14Joint Base Andrews:

A Detective Story (Part 2)

Clues from CCl4 Regression Analysis

Clues From CCl4 Well Data – MWs 23, 24, and 01

Evidence of Displacement

0

2

4

6

8

10

12

14

16

18

20Ja

n-0

8

Feb

-08

Mar

-08

Ap

r-0

8

May

-08

Jun

-08

Jul-

08

Au

g-0

8

Sep

-08

Oct

-08

No

v-0

8

Dec

-08

Jan

-09

Feb

-09

Mar

-09

Ap

r-0

9

May

-09

Jun

-09

Jul-

09

Au

g-0

9

Sep

-09

Oct

-09

No

v-0

9

Dec

-09

Jan

-10

Feb

-10

Mar

-10

Ap

r-1

0

Co

nce

ntr

atio

n

Sample Date

MW 24 DO and CT Concentrations

DO (mg/L)

CT (ug/L)

6,0

00

ga

l (5

,6)

12

,50

0 g

al (5

,6,7

)

2,0

00

ga

l (5

,6)

6,0

00

ga

l (5

,6)

6,5

00

ga

l (5

,7)

4,5

00

ga

l (6

,7)

Sodium Lactate

The Tools: BTEX Remediation -Aerobic Respiration

PermeOx® Plus injections

120 pounds of PermeOx® Plus in 120 gallons of water per point

One foot increments from 32’ to 19’ bgs

First: October 2007 (40 points, 4,800 lbs PermeOx® Plus)

Second: July 2009 (10 points, 1,200 lbs PermeOx® Plus)

Third: May 2010 (8 points, 960 lbs PermeOx® Plus)

Total = 6,960 lbs

Clues from Benzene Regression Analysis

Clues from Ethylbenzene, Toluene, and Total Xylene Regression Analysis

Clues From BTEX Well Data – MWs 10 and 04

Substrate Competition

0

10

20

30

40

50

60

70

Co

nce

ntr

atio

n in

mg

/L

Sample Date

MW 10 Total BTEX and DO Concentrations

DO

Total BTEX

20.000 gal (3,4)

20,000 gal (3,4)12,000 gal (3)

7,500 gal (3)

7,500 gal (3)

7,500 gal (3)

4,800 lbs

2,500 gal (8,9)

4,000 gal (3,8,9)

2,500 gal (8,9)

1,200 lbs

980 lbs

Sodium Lactate

PermeOx

Conclusion - What can we deduce from the available evidence?

The preponderance of the evidence suggests that:

– Remediation of contaminants at Site ST-14 was only marginally effective

• Limited in extent and duration

• Contaminant reductions primarily the result of displacement and dilution

– Reductive dechlorination appears to be limited by recharge of oxygenated water through the Calvert Formation and the method of substrate addition

• Difficulty in establishing and maintaining low DO concentrations

• Inconsistent production of microbial biomass

• Reductive dechlorination of TCE generally stalls at DCE

Lessons Learned (Site Characterization)

Fit the theory to the facts, not the facts to the

theory

–Calvert Formation was considered a regional aquitard in spite of available data that suggested otherwise

–Demonstrates the need for a complete and accurate conceptual site model

Lessons Learned (Substrate Injections)

When designing a remedial approach involving

substrate injections:

–Ensure groundwater flow gradient is sufficient to overcome injection-related mounding effects

–Consider limiting perpendicular injections to laterally limited hydrogeologic systems (e.g. paleochannels)

Lessons Learned (Remediation)

Do not try to promote aerobic respiration of

certain contaminants (BTEX) while simultaneously

trying to promote reductive dechlorination of other

compounds (TCE) in close proximity

Lessons Learned (Data Analyses)

Statistics and trend analyses do not always tell

the whole story and can be misleading

When evaluating the performance of reductive

dechlorination, consider changes in concentration

of the daughter products in addition to the primary

contaminant of concern

Site conditions are dynamic and change with time,

groundwater movement, and remedial activity

Lessons Learned (Plume Depictions)

Contaminant plume depictions are generated

based on kriging algorithms found in the individual

software systems

–Results influenced by contaminant concentrations, and data quality and density

–Use professional judgment when drawing conclusion for software generated plume maps

Lessons Learned (Third Party Review)

An independent third party review can be useful by

providing an objective assessment of the available

data to provide an alternative perspective.

Closing Argument

It is an old maxim of mine that when you have

excluded the impossible, whatever remains,

however improbable, must be the truth.

Sherlock Holmes in “The Adventure of the Beryl

Coronet” by Sir Arthur Conan Doyle

remediation evaluation at site st 14 jba

Documents

gallons of eos

gallons of water

longterm monitoring

vehicle washracks draft

scene hydrogeology

gravel range

lbs permeox plustotal

lbs permeox plussecond