Oil pollution & FM&A guest lecture (Week 12) Flashcards
What is crude oil
A complex mixture of hydrocarbons, organic compounds and a small amount of metals
Where does oil come from
Tiny flora & fauna organisms die on sea bed covered by layers of sand & silt.
Over millions of years remains buried deeper and deeper, enormous heat & pressure turn them into oil & gas.
Today drill through earth to reach rock formation that contains oil and gas deposits.
Sources of oil pollution in tankers
Tanker operations: >1.8 billion tonnes of oil transported by sea annually.
Dry docking
Tanker accidents
General shipping industry
Sources of oil pollution in the ocean
Offshore oil production: Oil drilling produces oil containing wastes that are dumped at sea.
Coastal oil refineries: Plants where crude oil is processed to make petrol, diesel etc. produce a waste water that is released at sea.
Licensed dumping at sea: Spoils from dredging ports & shipping channels.
Sources of oil pollution before it gets to the sea
Urban runoff: Waste oil from cars, trucks, garages etc. end up in rivers & sea in runoff.
Atmospheric inputs: Engine fumes, oil platforms and evaporation from the cargoes of oil tankers.
What was the largest accidental oil spill in history
The Deep Water Horizon Oil Spill that occurred on April 20th 2010 on an offshore oil drilling rig operated by BP.
Estimated 4.9 billion barrels/780 million litres released into ocean
What is an oil slick
When liquid oil is spilled at sea and spreads over the surface of the water.
How does spilled oil disperse in the ocean
Low molecular weight constituents evaporation
Water soluble components dissolve in water column
Wave action causes emulsion also determines oil movement
Where can oil disperse to after a spill
Some components sink to seabed and incorporate into sediments
Naturally occurring microorganisms can biodegrade on some constituents of oil
Some constituents oxidise when interact with air
- higher molecular weight fractions form tar balls (1mm - 20cm)
The rate at which oil spreads, is biologically degraded and the extent of the environmental damage that it causes depends on what factors:
Nature of spill: composition, duration, quantity
Environmental conditions: Air?water temp, weather, time of year.
Species composition of the area
Shoreline properties (rocky, sandy, mudflat, mangroves)
Amount of oil-degrading micro-organisms in the area
Supply of oxygen in the water
What measures were taken to suppress the effect of the Deepwater Horizon Oil Spill
Some oil captured by efforts to contain the spill
Some burned or skimmed from surface
Some dissolved or evaporated
Some naturally and chemically dispersed
Some still at sea
What measures were taken to suppress the effect of the Deepwater Horizon Oil Spill
Some oil captured by efforts to contain the spill
Some burned or skimmed from surface
Some dissolved or evaporated
Some naturally and chemically dispersed
Some still at sea
What happened in May 2010 after the Deepwater Horizon Oil Spill
In May 2010 large plumes of oil found underwater. 10 miles ling and 3 miles wide
What happened in June 2010 after the Deepwater Horizon Oil Spill
Oil hit the coast of Florida.
Slick and tar balls hit Mississippi, Louisiana, Alabama, Texas & Florida.
What happened in August 2010 after the Deepwater Horizon Oil Spill
oil deposits that matched the Deepwater Horizon spill found on the seabed.
Why mitigate oil damage at sea
Its easier to deal with at sea before it hits the coast
Oil skimmers collect slicked oil that an be deflected away from sensitive sites.
Contained oil is burned and residue collected and disposed of
What can be used to break up oil slick
Chemical dispersants to speed up emulsification process.
Dispersants may harm naturally occurring mocrobes that help breakdown oil.
What is bioremediation
The removal of pollutants by micro-organisms
What is Biostimulation
Addition of nutrients to speed up the process of biodegradation on oil
How do oil eating microbes work
The microbes break apart the hydrocarbons and combine them with oxygen to create water and carbon dioxide.
What does adding fertilizers to oil eating microbes do
Can increase the size and number of of microbes to eat more oil. Too much can cause algae blooms which will starve the ecosystem of light and oxygen
What does adding fertilizers to oil eating microbes do
Can increase the size and number of of microbes to eat more oil. Too much can cause algae blooms which will starve the ecosystem of light and oxygen
How much toxic chemical dispersants were used in response efforts to the Deep Water Horizon spill
1.8 million gallons.
BP were criticized for not using the least toxic dispersant available
What did people use in the gulf of Mexico to clean up marshland habitats from oil spill
Booms, Vacuums and ‘Slick lickers’
