Remediation of crude oil impacted onshore sites- case studies from Nigeria

1. Dr. Chinwe Mogo
B.sc(Botany),PGD(Environmental Science &
Technology),Msc.(Ecotoxicology), Ph.D
(Ecology/Ecotoxicology)
Federal Ministry of Environment, Nigeria
Dr.(Mrs.) Felicia Chinwe Mogo
Contact me: felichimogo@yahoo.com
LinkedIn: Felicia Chinwe Mogo

2.  THE 1ST INTERNATIONAL CONFERENCE
ON THE IMPROVED PRODUCTION OF OIL
AND IN THE GULF OF GUINEA.
 ORGANISED BY UNIVERSITY OF CALGARY,
CANADA AND CELLS ENVIRONMENTAL
SYSTEMS CANADA
 AT NICON LUXURY HOTEL ABUJA
 DATE: 1ST TO 3RD OF APRIL,2009

3. The exploration and exploitation of crude oil
resources in spite of its overwhelming economic
importance in Nigeria, has evidently been
associated with environmental degradation.
Frequent incidents of crude oil spills have resulted
in contamination of farmlands, portable water
supply and ecosystem imbalance. Recent reports
have indicated increased cases of danger of these
spills to the local communities in the oil producing
region.

4. The fact that proceeds from oil and gas exploration in
Nigeria has formed the bedrock of the Nation’s
economy cannot be over-emphasized.
However, judging from the history of oil and gas
activities in Nigeria, it is evident that remediation
of the crude oil impacted sites started receiving
serious attention in the recent time.
A lot of technologies have been employed in an
attempt to achieve remarkable restoration of the
impacted sites.
Hence, my talk today will dwell on the above subject
matter.

6.  The Nigerian Coastal Zone experiences a tropical climate consisting
of a rainy season (April to October) and a dry season (November to
March).
 Diurnal temperature is high reaching 340C to 350C.
 Relative humidity is high throughout the year and rarely go below
60%.
 High rainfall of between 3000mm and 4000mm is experienced
during the months of May to September with a short dry break in
August.
 Dry season lasts between October to March

7.  1908- Nigerian Bitumen Co and British colonial petroleum commenced operations around
Okitipupa
 1938-Shell D’Arcy granted Exploration licence to prospect for oil throughout Nigeria
 1955-Mobil Oil corporation started operations in Nigeria
 1956- First successful well drilled at Oloibiri by Shell D’Arcy.
 1956-changed name to Shell-Bp petroleum Development company of Nigeria Limited
 1958-First shipment of oil from Nigeria
 1961-Shell’s Bonny terminal was commissioned Texaco overseas started operations
 1962-Elf started OPERATIONS IN Nigeria (As Safrap) Nigeria Oil company started operation
in Nigeria
 1963-Elf discovered Obaji field and Obata gas field Gulfs first production
 1965-Agip found its first oil at Ebocha, Philips Oil started operations in The Bendel state.

 1966-Elf started production in Rivers state with 12,000b/d.
 1967-Philips drilled its first well (Dry) at Osari ).Philip 1st oil discovery at Gilli-Gilli
 1968-Mobil producing Nigeria limited was formed, Gulfs terminal at Escravos was
commissioned
 1970- Mobil started production from 4 wells at Idaho field.Agip

8.  Equipment failure
 Maintenance or operational error
 Vandalism (oil facility third party interference)
 Corrosion of pipelines
 Oil production and exploitation activities
 Oil theft

11.  Tier response approach to oil spill:
 Tier 1: localised spills < 2000bbls: house.
 Tier 2: 2000 – 10,000bbls: facility +
assistance from CNA
 Tier 3: > 10,000bbls: activation of
National oil spill contingency plan,
external bodies and oversea agencies.

12. • Containment
• Joint Inspection Team & Recovery
• Assessment & Clean-up
• Remediation/site Restoration
• Certification.

13. Past major oil spill incidents in Nigeria include :
-Funiwa-5 well blowout in 1980 -400,000 bbls
crude oil
-Oyakama oil spill in 1980 -30,000 bbls crude oil
-Oshika oil spill in 1983 – 10,000 bbls crude oil
-ldoho oil spill in 1998 – 40,000 bbls(approx 6,000
tonnes) crude oil

14.  Most of the natural attenuation processes
such as evaporation, dispersion, dissolution
and sedimentation, lead to the disappearance
of oil from the soil surface. Viscosity however
promote its persistence.
 Climatic conditions, availability of
degrading micro-organism and nutrient such
as nitrogen and phosphorous are important
factors of the process.

15.  Alteration of Biodiversity
 Destruction of Farmlands
 Human Insecurity/communal
clashes
 Accumulation of toxicants in the
foodchain
 Pollution of underground water
table
 Loss of revenue

18. WHAT IS REMEDIATION?
Remediation in this case is the
restoration of the land area affected
by the uncontrolled discharge of oil
(still in a state of nature) consisting
of a complex mixture of
hydrocarbons of various molecular
weights, plus other organic
compounds.

19.  In response to governmental regulation:
Polluter pays principle of the government
which considers the points below:
 Assessments of risk to human health
 Ecological risk
 aesthetics reasons
 Economic reasons

20.  Remediation framework should :
 Offer optimal protection of human health and
the environment
 Should be kind to the Environment
 Practical and resource- efficient approach
 Be better appreciated if it could allow
corrective actions and redevelopment to
proceed simultaneously.

21.  Physical- chemical technique: This is not based on none
biological processes. It requires large amount of energy to be
supplied to the system in order to remove the
pollutants(hydrocarbon )from the soil. This technique not
only being very expensive, also generates secondary
waste streams in form of carbon ash, carbon fumes
and carbonized sand residue.
 Bioremediation: based on the possibility of pollutants (
hydrocarbons) to undergo a more or less complete
degradation due to the activity of specific micro- organisms.
 According to the way of conducting the activities, the
techniques are subdivided into: In situ, on site and off site
techniques.

22. THERMAL REMEDIATION USING
THERMAL DESORPTION UNIT(TDU) TDU
 Thermal remediation involves
introducing hydrocarbon
contaminated soils into a heated
vessel and retaining those soils
until they reach a uniform
temperature. The operating
temperatures are limited to less
than 800F, due to the potential for
releasing dioxins into the
atmosphere.
 Though the method applies
satisfactorily to hydrocarbon
polluted soils but it requires high
amount of energy for the heating
and treated soil becomes sterile.
This makes the method less
attractive for site final restoration.

23.  Encapsulation: It involves the mixing of the
contaminated soils with other products such as
lime, concrete, or asphalt. The contaminated
soil becomes part of the product mix and the
contamination is thereby prevented from
migrating to surrounding strata.

24.  Incineration: This thermal treatment
technology involves the combination of the
pollutant. The waste materials are converted
into incinerator bottom ash,flues gases,
particulates, and heat. The flue gases are
cleaned of pollutants before they are dispersed
in the atmosphere

25. AIR SPARGING
MECHANISM
 It involves the
biodegradation of the
pollutants in the subsoil and
the aquifer by providing the
bacteria with the oxygen
required for the oxidation of
the Hydro-carbons by
pumping air into the
saturated parts of the aquifer
by means of injection of
wells. This forces the organic
vapours to the surface where
they are then treated by
carbon filtering or other
means.

26. BIOVENTING MECHANISM
1. Bioventing: This method is used on
hydrocarbon spills where it is not
possible to disturb the contamination
site. This method combines biotreatment
with air injection, or soil vapor
extraction. It involves pumping small
amounts of oxygen into the contaminated
soil strata(subsoil1 to 2 m of depth
thereby stimulating microorganism
growth, which then break down the
hydrocarbons into carbon dioxide and
water. Cost of the process ranges from
$10-$50/TON of contaminated soil. The
disadvantage is that this method takes
five times as long as air sparging

27.  Phyto-remediation:An emerging technology
based on in-situ bioremediation through the use of
plants.
It Involves the degradation of organic and
inorganic contaminants through internal and external
processes driven by the plant
Some of these processes occurs within the plants and
Some contaminants can
be absorbed by plants and are then broken down by
plants enzymes which may be used by plants
themselves
as they grow.

28.  Research has proven thatTectona grandis and Gmelina arborea
are good forest species for the phyto- remediation of crude oil
contaminated in Nigeria. Plants like effective in phtytoremediation
Abelmoschus esculentus (vegetable), Telfaria occidentalis (vegetable)
and vigina unquiculata (legume) and Zea mays (corn) and
Pennisetum purpureum (elephant grass). have been very effective
remediation of imparted farmlands.
Phytoremediation is usually said to be clean, efficient,
inexpensive and non-environmentally disruptive, as
opposed to processes that require excavation of soil.

29.  Enhance Natural Attenuation(RENA):This
form of bioremediation is a technology
involving intensive and systematic land-
farming and windrowing approach to
maximize the factors that promote
biodegradation of hydrocarbons by indigenous
soil bacteria (e.g. access to oxygen, water, heat,
light, nutrients), and physico-chemical
processes acting together to reduce
hydrocarbon concentration.

30.  The Tropical climate of the Niger Delta,
characterized by abundant sunshine, frequent
rainfall and high-biotic habitats, supports RENA
method.
 The results of a study that evaluated the
effectiveness of RENA by a group in Nigeria
shows that a significant reduction of the
hydrocarbon compounds in crude oil spill
contaminated soil can be achieved within 40 days
of application of RENA remediation technique in
humid tropical climatic conditions as in Niger
Delta Nigeria


33. POST-REMEDIATION OF OBIGBO- W-29 BORROW –PIT RENA
BIOCELL
PRE-REMEDIATION OF OBIGBO- W-29 BORROW –PIT RENA
BIOCELL
OBIBGO W-29 BORROW PIT - PRE-REMEDIATION
- APRIL 2002.
OBIBGO W-29 BORROW PIT - POST-REMEDIATION –
JUNE 2004.

34. November 2000 JUNE 2002
BEFORE REMEDIATION
2002 AFTER REMEDIATION
AGBADA W-52 TEMPRORARY RETENTION PIT [TRP]

35. AGBADA WELL 56 TEMPORARY RETENTION PIT
INBefore Remediation After Remediation
NOVEMBER 1999 JUNE 2002

36. Agbada Well-35/54 Temporary Retention Pit
May 2001 January 2002
Before Remediation After Remediation

37.  Bioremediation by Land farming /RENA mostly applied in
Nigeria: Said to be effective, cost saving and environmentally
friendly
 Phytoremediation : Environmentally friendly. Its use is more
common with heavy metals though a lot of researches are
ongoing with its effectiveness for crude oil
 Incineration: Encapsulation: Used mostly when it involves
drill cuttings and mud.
 Thermal Decomposition: In use in some instances. It is not
only very expensive, but also generates secondary waste
streams in form of carbon ash, carbon fumes and carbonized
sand residue.

38.  Is RENA the best option?
 What would happen to the associated heavy
metals?
 No threat to biodiversity?
 Can allien species be introduced?
 How “clean is clean”

39.  Spill prevention and minimization is the best! i.e. through Assets Integrity,
Periodic facility integrity checks, replacement of obsolete pipelines and
equipment, Assets Preservation, Maintenance of pipeline right-of-way (ROW),
prohibition of activities on/within ROW, Enlightenment Campaigns, sensitization
workshops on the dangers of pipeline vandalism, environmental awareness
programmes.
 Sustainable management of the oil spill Incident to avoid more damage to
the environment
 Oil spill clean up techniques that are efficient and effective i.e. that cause
little or no impact to man and his environment but can effectively remove
the spilled oil should be applied always
 Combination of technologies should be used when necessary.
 Need to embark on post-remediation studies to ensure sustainable
restoration of impacted areas.
 There should be cooperation amongst Regulatory Authorities with cross-
cutting mandates in regulation of pollution control in Oil and gas
industries.