Bioremediation of petroleum hydrocarbons in contaminated soil

1. Halime Almasi

2. Bioremediation of petroleum hydrocarbons
in contaminated soil

3. Total petroleum hydrocarbons (TPH)
Crude oil is used to make petroleum products which
can contaminate the environment. Because there are
so many different chemicals in crude oil and in other
petroleum products, it is not practical to measure each
one separately. Chemicals that occur in TPH include
hexane, benzene, toluene, xylenes, naphthalene, and
fluorine, other constituents of gasoline, of jet fuels,
and of other petroleum products.

4. Crude Oil
Hydrocarbon
• Oil and gas are made of a mixture of
different hydrocarbons.
• As the name suggests these are large
molecules made up of hydrogen atoms
attached to a backbone of carbon.

5. TPH is the sum of VPH and EPH. VPH refers to volatile
petroleum hydrocarbons (VPH) also known as petrol
range organics (PRO) and includes hydrocarbons from
C2-C5. Diesel range organics (DRO) includes
hydrocarbons from C10-C28. Various methods to
analyse the components of TPH are introduced in a
Nordic report.

7. Using microorganisms to
transform hazardous
contaminants into relatively
harmless byproducts.
Bioremediation

8. There are the two main
approaches to oil spill
bioremediation:
Bio augmentation – adding
biodegrading organisms to the
contaminated site (not
genetically manipulated)
Bio stimulation – adding
nutrients like nitrogen or
phosphorus in order to
stimulate microbial activity

9. Bacteria
Plants(Phytoremediation)
Fungi

10. Advantages of Bioremediation

11. • Fundamentally bioremediation uses
microorganisms (e.g. bacteria, yeast and fungi) to
break down harmful contaminants
• This can be facilitated by using native indigenous
microbes or by adding foreign exogenous ones to
populate the soil
• Different types of microorganisms function well
in different conditions:
– Oligotrophs function well in low carbon
environments
– Eutrophs function well in high carbon
environments
Theory

13. Bioremediation by plants

15. Types of bioremediation
Ex situIn situ
•Biosparging
•Bioaugmentation
•Biopiles
•Bioventing
On the basis of removal and transport of contaminants
•Composting
•Land farming
•Bioreactors

16. In situ bioremediation
• Treatment of contaminated soil or ground
water in the location where it was found.
• Usually microorganism are pumped into the
soil or ground water so that the contaminated
soil and water can be broken down.

17. Low cost
Causes minimal site disruption
Simultaneous treatment of contaminated water and soil
Requires minimal exposure of public and site personal.
 It is a cost-effective method as no transportation cost applies.

18.  In-Situ bioremediation without human intervention.
 microorganisms that are naturally present in contaminated matrix
 The rate of contaminant migration should be less than the rate of
contaminant degradation.
 The success of intrinsic bioremediation depends on;
 The bioavailability of contaminants
 The adequate level of nutrients
 The presence of minerals to buffer the pH of the matrix

19. Ex situ bioremediation
The contaminated water and soil are pumped out and treated with
microorganisms and when the materials are degraded the soil and
water are placed in a bed with oxygen and rich nutrients for further
degradation.
i.Solid Phase System (includes land treatment)
ii.Slurry Phase System (including solid–liquid suspensions in
bioreactors

20. 
Biosparging
Biosparging involves the injection of air under
pressure below the water table to increase
groundwater oxygen concentrations and enhance
the rate of biological degradation of contaminants
by naturally occurring bacteria.
Types of In-situ
bioremediation

21. Bio augmentation
introduction of genetically engineered strains of microbes to a contaminated
site. can be introduced to successfully degrade specific waste compounds.
Biodegradation refers to the degradation of organic contaminants in soil by
indigenous or transplanted microorganisms, primarily bacteria and fungi.
Limitations
Certain characteristics in the soil matrix preferential.
flow paths
ofinjected
fluids
poor contact
between microbes
and contaminants.
may result
in

22. Bioventing
Applicability
Bioventing is applicable to any chemical that can be aerobically
biodegraded. Techniques have been successfully used to remediate
soils contaminated by petroleum hydrocarbons, non-chlorinated
solvents, some pesticides, wood preservatives
Limitations
Factors that may limit the applicability and effectiveness of the
process include:
(1)low permeability soils (reducebioventing performance);
(2)monitoring of off-gases at the soil surface may be required;
(3)low soil moisture content, which may be caused by
bioventing, limits biodegradation .

23. Bioventing

24. 
Types of In-situ
bioremediation
Soil biopiles
•Biopiles are a hybrid of land farming and composting.
•use for treatment of surface
contamination with petroleum hydrocarbons
•They are a refined version of land farming that tend cont
rol physical losses of the contaminants by leaching and v
olatilization.
•Biopiles provide a favorable environment for indigenou s
aerobic and anaerobic microorganisms.

33. 
Types of Ex-situ bioremediation
1.Composting
•contaminated soil is combined with nonhazardous
organic components such as manure or agricultural
wastes.
•The presence of organic materials supports the
development of a rich microbial population and
elevated temperature characteristic of composting.
2.Land farming
•Contaminated soil is excavated
•Spread over a prepared bed
•Periodically tilled until pollutants are degraded.

34. 
•Containment vessel used to create solid,
liquid and gas phases.
•Mixing condition to increase the bioreme
-diation rate of soil bound and water- soluble
pollutants.
3. Bioreactors

37. 