biodegradation study of diesel and surrogate compounds of
DESCRIPTION
A laboratory study of biodegradatiTRANSCRIPT
Biodegradation Study of Biodegradation Study of Diesel and Surrogate Diesel and Surrogate Compounds of DieselCompounds of Diesel
Todd R. CrawfordTodd R. Crawford
Crawford Independent Crawford Independent AnalystsAnalysts
BiodegradationBiodegradation
……the biologically catalyzed reduction the biologically catalyzed reduction in complexity of chemicals… in complexity of chemicals… (Alexander 1994)(Alexander 1994)
Organic compounds are frequently Organic compounds are frequently biodegraded to inorganic chemicals – biodegraded to inorganic chemicals – mineralizationmineralization
A desirable approach to site A desirable approach to site remediationremediation
Incomplete BiodegradationIncomplete Biodegradation
A threshold concentration is reachedA threshold concentration is reached Remaining material cannot be Remaining material cannot be
biodegraded by:biodegraded by:• Aeration, orAeration, or• Addition of nutrientsAddition of nutrients
This phenomenon is seen for most This phenomenon is seen for most organic chemicals biodegrading in organic chemicals biodegrading in soilsoil
Causes of Incomplete Causes of Incomplete BiodegradationBiodegradation
Contaminant may be adsorbed into Contaminant may be adsorbed into microporesmicropores
Contaminant may be adsorbed into soil Contaminant may be adsorbed into soil organic carbonorganic carbon
Microorganisms may be inhibited by some Microorganisms may be inhibited by some biodegradation byproductbiodegradation byproduct
Amount of contaminant may not be Amount of contaminant may not be sufficient to support biological activitysufficient to support biological activity
Remaining contaminant may not be Remaining contaminant may not be composed of biodegradable materialcomposed of biodegradable material
Diesel FuelDiesel Fuel
Several thousand chemicalsSeveral thousand chemicals Mostly carbon and hydrogen Mostly carbon and hydrogen
(hydrocarbons)(hydrocarbons) AliphaticsAliphatics
• Straight chain alkaneStraight chain alkane• Branched chain alkaneBranched chain alkane
AromaticsAromatics• Polycyclic Aromatic Hydrocarbons Polycyclic Aromatic Hydrocarbons
(PAHs)(PAHs)
GC-FID trace of diesel fuelGC-FID trace of diesel fuel
min5 10 15 20 25 30 35
pA
0
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60
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120
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160
180
FID1 A, (07-31-06\004F0401.D)
SiteSite
Rhode IslandRhode Island Former petroleum distribution Former petroleum distribution
terminal terminal Approximately 100 acresApproximately 100 acres Approximately 150,000 cy diesel Approximately 150,000 cy diesel
contaminated soilcontaminated soil Remediation goal 500 ppm TPHRemediation goal 500 ppm TPH Ex situ biodegradationEx situ biodegradation
Incomplete BiodegradationIncomplete Biodegradation
Biodegradation ceased around 1000 Biodegradation ceased around 1000 ppm TPHppm TPH
Weekly tilling (aeration) did not Weekly tilling (aeration) did not stimulate biodegradationstimulate biodegradation
Soil amendments did not stimulate Soil amendments did not stimulate biodegradationbiodegradation
Holding up the project!Holding up the project!
SoilsSoils
U2A – treatment soilU2A – treatment soil• Silty sand from shore areaSilty sand from shore area• Initial TPH concentration ~3000 ppmInitial TPH concentration ~3000 ppm• Final TPH concentration ~1000 ppmFinal TPH concentration ~1000 ppm• Air-dried for 24 hoursAir-dried for 24 hours• Sieved Sieved • Air-dried for 24 hoursAir-dried for 24 hours• Stored in 1-Liter glass jars in refrigerator Stored in 1-Liter glass jars in refrigerator
until useduntil used
Biodegradation StudyBiodegradation Study
Is the petroleum sequestered in the Is the petroleum sequestered in the soil – not available to soil – not available to biodegradation?biodegradation?
Is the remaining petroleum not Is the remaining petroleum not biodegradable?biodegradable?
TPH Redistribution ExperimentTPH Redistribution Experiment
If petroleum is sequestered in soil, If petroleum is sequestered in soil, then let’s redistribute it…then let’s redistribute it…
1.1. Out of soil pores onto soil surface Out of soil pores onto soil surface where it is bioavailable…where it is bioavailable…
2.2. Out of soil onto another soil where Out of soil onto another soil where it may be more bioavailable…it may be more bioavailable…
Redistribution setupRedistribution setup
U2A soilU2A soil U2A soil shaken with methylene U2A soil shaken with methylene
chloride and evaporated at room chloride and evaporated at room temperaturetemperature
U2A soil extract (methylene chloride) U2A soil extract (methylene chloride) transferred to sandy soil and transferred to sandy soil and evaporated at room temperatureevaporated at room temperature
Diesel fuel in sandDiesel fuel in sand
Redistribution Experiments
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2/14/1999 2/19/1999 2/24/1999 3/1/1999 3/6/1999 3/11/1999 3/16/1999 3/21/1999 3/26/1999 3/31/1999
Sample Date
TP
H c
on
c. (
pp
m)
U2A soil U2A redistr. Sand with U2A extract Sand with diesel
IndicationsIndications
Little or no significant biodegradation Little or no significant biodegradation of the remaining diesel in:of the remaining diesel in:• U2A soil without redistributionU2A soil without redistribution• U2A soil with redistributionU2A soil with redistribution• Sand with U2A soil extractSand with U2A soil extract
Biodegradation did occur for diesel in Biodegradation did occur for diesel in sand – the setup should biodegrade sand – the setup should biodegrade the contaminantthe contaminant
Surrogate Biodegradation Surrogate Biodegradation ExperimentExperiment
Is the remaining petroleum non-Is the remaining petroleum non-biodegradable – not bioavailable?biodegradable – not bioavailable?
1.1. Add surrogates of diesel to soilAdd surrogates of diesel to soil
2.2. Add surrogates of diesel to soil Add surrogates of diesel to soil extract in another soilextract in another soil
Selected Diesel SurrogatesSelected Diesel Surrogates
Hexadecane – straight C-16 alkaneHexadecane – straight C-16 alkane Octacosane – straight C-28 alkaneOctacosane – straight C-28 alkane Pristane – branched C-19 alkanePristane – branched C-19 alkane Squalane – branched C-30 alkaneSqualane – branched C-30 alkane Phenanthrene – C-14 PAHPhenanthrene – C-14 PAH
100 ppm of each surrogate added to 100 ppm of each surrogate added to soilssoils
Biodegradation of Surrogates in U2A SoilWithout Redistribution
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2/14/1999 2/19/1999 2/24/1999 3/1/1999 3/6/1999 3/11/1999 3/16/1999 3/21/1999 3/26/1999 3/31/1999
Date
Su
rro
gat
e co
nc.
(p
pm
)
B hexadecane B pristane B phenanthrene B squalane B octacosane
Biodegradation of Surrogates in U2A Soilwith Redistribution
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2/14/1999 2/19/1999 2/24/1999 3/1/1999 3/6/1999 3/11/1999 3/16/1999 3/21/1999 3/26/1999 3/31/1999
Date
Su
rro
gat
e co
nc.
(p
pm
)
A hexadecane A pristane A phenanthrene A squalane A octacosane
Biodegradation of Surrogates with U2A extract in Sand
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2/14/1999 2/19/1999 2/24/1999 3/1/1999 3/6/1999 3/11/1999 3/16/1999 3/21/1999 3/26/1999 3/31/1999
Date
Su
rro
gat
e co
nc.
(p
pm
)
E hexadecane E pristane E phenanthrene E squalane E octacosane
ObservationsObservations
Branched alkanes are biodegrading Branched alkanes are biodegrading slowlyslowly
Longer alkanes are biodegrading Longer alkanes are biodegrading slower than shorter alkanesslower than shorter alkanes
Phenanthrene is biodegrading faster Phenanthrene is biodegrading faster than other surrogates!?than other surrogates!?
ConclusionsConclusions
Biodegradation is inhibited in the site Biodegradation is inhibited in the site soils by a chemical that is transferred soils by a chemical that is transferred with the methylene chloride extractwith the methylene chloride extract
And/OrAnd/Or Most of the remaining material is Most of the remaining material is
branched alkanesbranched alkanes
AcknowledgementsAcknowledgements
Jim Smith and Les Eng, Trillium Inc.Jim Smith and Les Eng, Trillium Inc. John E. Ross, CTEH LLCJohn E. Ross, CTEH LLC José A. Amador, URIJosé A. Amador, URI