contaminated land: dealing with hydrocarbon contamination petroleum hydrocarbons – occurrence,...

23
Contaminated land: Contaminated land: dealing with hydrocarbon dealing with hydrocarbon contamination contamination Petroleum hydrocarbons – Petroleum hydrocarbons – occurrence, composition and occurrence, composition and significance significance

Upload: mohammed-haidle

Post on 16-Dec-2015

241 views

Category:

Documents


2 download

TRANSCRIPT

Contaminated land: dealing Contaminated land: dealing with hydrocarbon with hydrocarbon

contaminationcontamination

Petroleum hydrocarbons – Petroleum hydrocarbons – occurrence, composition and occurrence, composition and

significance significance

Environmental Simulations International

Contents of Contents of presentation presentation

Sources of hydrocarbon Sources of hydrocarbon contaminationcontamination

Composition of oilsComposition of oils Non-hydrocarbon components of oilNon-hydrocarbon components of oil Hydrocarbon behaviour in the Hydrocarbon behaviour in the

subsurfacesubsurface The most important components?The most important components?

Environmental Simulations International

Potential hydrocarbon-Potential hydrocarbon-contaminated sites – 1contaminated sites – 1

Stating the obviousStating the obvious– Filling stations, distribution depotsFilling stations, distribution depots– Oil production, refineries and Oil production, refineries and

associatedassociated– Garages/automotive industryGarages/automotive industry– Haulage yardsHaulage yards– Scrap metal industryScrap metal industry– Airports, aerospace industryAirports, aerospace industry– Waste processing & disposalWaste processing & disposal

Environmental Simulations International

Potential hydrocarbon-Potential hydrocarbon-contaminated sites – 2contaminated sites – 2

And also…And also…– GasworksGasworks– Metalworking industryMetalworking industry– Paints/inks/coatings industryPaints/inks/coatings industry– Anybody who uses solvents!Anybody who uses solvents!– Agricultural facilitiesAgricultural facilities– Anywhere with a boilerhouse/ Anywhere with a boilerhouse/

furnacefurnace Including domestic oil storageIncluding domestic oil storage

Environmental Simulations International

Composition of oilsComposition of oils

Crude oil and petroleum products Crude oil and petroleum products are complex mixturesare complex mixtures

They are characterised by differing They are characterised by differing boiling point ranges and boiling point ranges and componentscomponents– Carbon numbers/simulated distillationCarbon numbers/simulated distillation

Environmental Simulations International

Oil refiningOil refining

CrudeOil

Gasoline C4-C10 (80oC - 150oC)

Kerosene/Jet Fuel C11-C13 (150oC - 250oC)

Diesel Fuel C14-C18 (250oC - 325oC)

Heavy Gas Oil C19-C25 (325oC - 450oC)

Lubricating Oil C26-C40 (450oC - 500oC)

Residuum >C40 (> 500oC)

Environmental Simulations International

Main component Main component groupsgroups

Aliphatic hydrocarbonsAliphatic hydrocarbons Aromatic hydrocarbonsAromatic hydrocarbons NSO componentsNSO components

– Nitrogen, sulphur and oxygen-Nitrogen, sulphur and oxygen-containing compoundscontaining compounds

– ““Polar components”Polar components”– ““Asphaltenes”Asphaltenes”

Environmental Simulations International

Aliphatic hydrocarbonsAliphatic hydrocarbons

Alkanes Saturated hydrocarbons - no double or triple bonds.(Paraffins)

Hexane

Alkenes/ Unsaturated hydrocarbons - double/triple bonds.Alkynes(Olefins)

Hexene

Cycloalkanes Saturated hydrocarbons with a ring structure.(Naphthenes)

Cyclohexane

C C C C C C

C C C C C C

Environmental Simulations International

Aromatic hydrocarbons Aromatic hydrocarbons - BTEX- BTEX

Benzene o-Xylene C6H6 C8H11

Toluene m-Xylene C7H8 C8H11

Ethylbenzene p-Xylene C8H10 C8H11

CH3 CH3

CH3

CH3

CH3

CH3

CH3

CH2CH3

Environmental Simulations International

Aromatic hydrocarbons Aromatic hydrocarbons – PAH’s– PAH’s

Polycyclic aromatic hydrocarbons (PAH)[polynuclear aromatic hydrocarbons (PNA)]

Naphthalene Benzo(a)PyreneC10H8 C20H12

PhenanthreneDibenzo(a,h)AnthraceneC14H10 C22H14

Pyrene FluorantheneC16H10 C16H10

Environmental Simulations International

Relative distribution of Relative distribution of components – an components – an exampleexample

C2-

C4

C4-

C6

C6-

C8

C8-

C10

C10

-C12

C12

-C14

C14

-C16

C16

-C18

C18

-C20

C20

-C22

C22

-C24

C24

-C26

C26

-C28

C28

-C30

C30

-C32

C32

-C34

C34

-C36

>C36

05

1015

2025

30

35

40

Wei

gh

t P

erce

nt

Carbon Number

Crude

Diesel

Gasoline

Environmental Simulations International

Hydrocarbon Hydrocarbon behaviour in the behaviour in the subsurfacesubsurface

Oil is a light non-aqueous phase liquid Oil is a light non-aqueous phase liquid (LNAPL)(LNAPL)– Residual oil will be held in pore spaces in soilResidual oil will be held in pore spaces in soil– Free oil “floats” on groundwaterFree oil “floats” on groundwater

The more soluble components can dissolve The more soluble components can dissolve in groundwaterin groundwater– MTBE & TAME are highly solubleMTBE & TAME are highly soluble

The more volatile components can partition The more volatile components can partition into soil gasinto soil gas

Sorption of components into/onto soil can be Sorption of components into/onto soil can be an important processan important process

Environmental Simulations International

Before Oil Flow Through Soil

During Oil Flow Through Soil

After Oil Flow Through Soilcapillary fringe

water table

soil surface

vadosezone

saturated zone

PetrolSpill

groundwater flow

Residual Hydrocarbons in Soil Pores

(soil contamination)

(~1% HC by weight)

Mobile & ResidualHydrocarbons(free-product)

(~9% by weight)

Volatilised Constituents

(vapour plume)

(~50mg HC/kg soil)

(~130 mg HC/L water)

Dissolved Constituents (plume)

How oil components How oil components might be distributedmight be distributed

Environmental Simulations International

NAPL – how?NAPL – how?

Oil in closed-end pore Residual oil trapped by water

Soil Matrix

Trapped NAPL

NAPL

Soil Matrix

Wetting Fluid (water)

NAPL

Environmental Simulations International

Why is NAPL Why is NAPL important?important?

Direct effects of oil at receptorDirect effects of oil at receptor– Also potential effect on buried materialsAlso potential effect on buried materials

Residual NAPL can also be a source of Residual NAPL can also be a source of contamination for long periods of contamination for long periods of timetime– Water soluble components can cause Water soluble components can cause

long-term groundwater plumes long-term groundwater plumes – Volatile components are a potential Volatile components are a potential

source of vapourssource of vapours

Environmental Simulations International

Petroleum Petroleum contamination – what contamination – what to look forto look for

Liquid phase (free-product NAPL) Liquid phase (free-product NAPL) Dissolved phase (groundwater Dissolved phase (groundwater

plume) plume) Solid phase (hydrocarbon attached Solid phase (hydrocarbon attached

to soil)to soil) Vapour phaseVapour phase Combination of several phasesCombination of several phases

Environmental Simulations International

How oil components How oil components might be distributed – might be distributed – exampleexample

0% 20% 40% 60% 80% 100%

ACENAPHTHENE

ACENAPHTHYLENE

2-METHYLNAPHTHALENE

NAPHYTHALENE

o-XYLENE

ETHYLBENZENE

p-XYLENE

m-XYLENE

TOLUENE

BENZENE

Vapour

Water

Sorbed

Environmental Simulations International

Non-hydrocarbon Non-hydrocarbon componentscomponents

Organic additivesOrganic additives– Petrol (gasoline): MTBE, TAMEPetrol (gasoline): MTBE, TAME– Fuels: proprietary performance additivesFuels: proprietary performance additives– Luboils: proprietary performance additivesLuboils: proprietary performance additives

MetalsMetals– Naturally occurring components of crudeNaturally occurring components of crude

e.g., vanadium, nickele.g., vanadium, nickel

– Significant contaminants in waste luboilsSignificant contaminants in waste luboils– Leaded petrol (TEL)Leaded petrol (TEL)

Max. 0.013 g/l in 1980’s leaded petrol but earlier or Max. 0.013 g/l in 1980’s leaded petrol but earlier or special use petrol could be higherspecial use petrol could be higher

– Proprietary performance additivesProprietary performance additives

Environmental Simulations International

MTBE Methyl tertiary butyl ether

CH3

CCH3O

CH3

CH3

Additives in unleaded Additives in unleaded petrolpetrol

TAMETertiary methyl amyl ether

C2H5

CCH3O

CH3

CH3

ETBE Ethyl tertiary butyl ether

CH3

CCH2CH3O

CH3

CH3

• MTBE most common in UK• Typically 1-5% in petrol• Highly soluble (26000 mg/l)• Very low taste/odour threshold

Environmental Simulations International

WeatheringWeathering

Preferential reduction in the concentration Preferential reduction in the concentration of some components relative to othersof some components relative to others– Biodegradation tends to favour removal of n-Biodegradation tends to favour removal of n-

alkanes (straight carbon chain alkanes), low alkanes (straight carbon chain alkanes), low molecular weight cycloalkanes and light molecular weight cycloalkanes and light aromaticsaromatics

– Volatilisation and dissolution tends to remove Volatilisation and dissolution tends to remove low molecular weight aromatics (especially low molecular weight aromatics (especially BTEX) and aliphaticsBTEX) and aliphatics

– Dissolution is very important for MTBE and Dissolution is very important for MTBE and TAMETAME

Weathering of organic lead additivesWeathering of organic lead additives

Environmental Simulations International

Weathering – aliphatic Weathering – aliphatic componentscomponents

So, weathered So, weathered hydrocarbon mixtures hydrocarbon mixtures are typically are typically significantly less significantly less mobile and less toxic mobile and less toxic than “fresh” mixtures than “fresh” mixtures

C15

C20C25

C30

10

20

30

0

Wt%

n- iso- cyclo-

10

20

30

0

Wt%

n- iso- cyclo-

10

20

30

0

Wt%

2 6-rings4

Environmental Simulations International

SummarySummary

Hydrocarbon contamination may arise Hydrocarbon contamination may arise at a wide variety of sitesat a wide variety of sites

Crude oils and petroleum products are Crude oils and petroleum products are complex mixtures of componentscomplex mixtures of components– We will discuss the implications further in We will discuss the implications further in

more detailmore detail Multiphase behaviour must be Multiphase behaviour must be

consideredconsidered Weathering may be importantWeathering may be important

Environmental Simulations International

The most important The most important components?components?

Certain groups of components often Certain groups of components often merit particular (but not sole) merit particular (but not sole) consideration, e.g.consideration, e.g.– BTEXBTEX

Toxicity, vapoursToxicity, vapours

– PAH’sPAH’s Potential carcinogenicity, relatively persistentPotential carcinogenicity, relatively persistent

BUT this depends on the source-pathway-BUT this depends on the source-pathway-receptor relationships that you are receptor relationships that you are consideringconsidering– Is the conceptual model sound?Is the conceptual model sound?