Remediation of Crude Oil Sites

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

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Remediation of Crude Oil Sites

  1. 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. 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. 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. 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.
  5. 5.  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
  6. 6.  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
  7. 7.  Equipment failure  Maintenance or operational error  Vandalism (oil facility third party interference)  Corrosion of pipelines  Oil production and exploitation activities  Oil theft
  8. 8.  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.
  9. 9. • Containment • Joint Inspection Team & Recovery • Assessment & Clean-up • Remediation/site Restoration • Certification.
  10. 10. 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
  11. 11.  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.
  12. 12.  Alteration of Biodiversity  Destruction of Farmlands  Human Insecurity/communal clashes  Accumulation of toxicants in the foodchain  Pollution of underground water table  Loss of revenue
  13. 13. 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.
  14. 14.  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
  15. 15.  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.
  16. 16.  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.
  17. 17. 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.
  18. 18.  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.
  19. 19.  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
  20. 20. 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.
  21. 21. 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
  22. 22.  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.
  23. 23.  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.
  24. 24.  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.
  25. 25.  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 
  26. 26. 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.
  27. 27. November 2000 JUNE 2002 BEFORE REMEDIATION 2002 AFTER REMEDIATION AGBADA W-52 TEMPRORARY RETENTION PIT [TRP]
  28. 28. AGBADA WELL 56 TEMPORARY RETENTION PIT INBefore Remediation After Remediation NOVEMBER 1999 JUNE 2002
  29. 29. Agbada Well-35/54 Temporary Retention Pit May 2001 January 2002 Before Remediation After Remediation
  30. 30.  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.
  31. 31.  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”
  32. 32.  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.

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