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

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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

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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

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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

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A hexadecane A pristane A phenanthrene A squalane A octacosane

Biodegradation of Surrogates with U2A extract in Sand

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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