oil pollution Flashcards
list the sources of oil pollution
1) waste lubricating oil
2) ship tank washing
3) tanker accidents
4) oil refinery spills
5) pipeline leaks
6) leakage during drilling
give some examples of waste lubricating oil
- vehicle engine oil which leaks or is disgraded into the environment
- industrial machine oil washed into drain or mixed with other effluents
outline how oil exploration is a cause of oil pollution
drilling= pipes need to be lubricated to reduce friction as they bore through rock- usually done with fine clay suspended in water, sometimes oil-based clays are used such as where rock would absorb water
what are the effects of oil pollution
1) asphyxiation - species that live on the seashore or surface ie mollusks can be asphyxiated, algae would be unable to photosynthesis
2) loss of insulation- oil causes bird feathers to stick together so they lose insulating properties which may cause hypothermia and death
3) less time to feed young- birds may be able to clean feathers if they only have a small bit of oil but it reduces the time available to feed young or themselves
4) food chain effects- causes the death hor prey species may impact predator populations or vice versa
5) deoxygenation= forms a thin layer on surface which prevents dissolved oxygen causing death of aerobic organisms
how can oil pollution be controlled
1) preventation techniques
2) improved oil tanker operation
3) improved tanker design
4) oil interceptors
5) bund walls
outline a oil pollution prevention technique
1) recycling of waste lubrication oil
- used lubricating oil from engines or machinery should not be treated as waste material
- contaminates can be removed and chemical reforming and distillation can produce commercially valuable lubricant again
- waste oil that cant be recycled can be burnt which reduces demand from other sources
outline some examples of improed oil tanker operation
1) better shipping routes- greater distance away from shore when possible providing time to deal with mechanical issues before it is carried ashore by currents
2) better navigation systems- new tech such as GPS enables more accurate navigation, AIS allows for positions of most ships to be monitored reducing collisions
3) tank washing procedures- oil tanks must be washed to prevent build-up of tar, usually dirty water is discharged into the sea, this is prevented by recirculating oil in tanks during unloading so sludge is removed with cargo
4) inert gas systems- in the past, the unloading of oil left space to fill up with air which produced an explosive mix of air and oil, cooled exhaust gases from engines replace the oil so no oxygen entry is possible
outline some improved tanker deigns
1) double-hull- tankers used to have a single layer of steel between oil and sea so any damage allowed the release of oil- tankers now have twin hulls with up to 2m between so damage doesn’t mean release
2) twin engines- any mechanical failures that affect steering or movement can cause ships to be carried by currents onto rocks causing spills- having pairs of essential equipment can save the ship if one breaks down
3) separate oil and ballast tanks- when the tankers are empty the tanks would be filled with ballast water to with down boat and ensure the hull is weighed down. this water would be discharged will oil into the water- now tanks are separate so when water returned to sea it is clean
what are oil interceptors
separate oil from watery waste such as drainage water from major roads or car parks where there may be floating oil
water flows into the main drainage system from the base of the tanks, but oil is retained as it floats so it can be removed for later treatment
what is a bund wall
oil storage tanks are built on impermeable bases surrounded by a bund wall which would contain oil if the tank were to split so oil wouldn’t leach into water bodies
list some treatments for oil spills
1) booms
2) skimmers = rotating discs that pick up oil that can be scraped off and stored later for disposal
3) absorbant materials= high surface area material such as mops can help absorb oils which can then be removed and disposed of
4) detergents = break up oil spills to produce emulsion droplets increasing mobility and may be broken down by bacteria
5) polymerising agents -chemicals developed that cause oil molecules to join together producing soil collectible materials
6) steam washing - doesn’t destroy oil but removes form sensitive areas
7) bioremediation
what are booms
an oil treatment method where inflatable tubes restrict the movement of floating oil
they do not work in open water where currents or waves are strong so they are used in sheltered areas to reduce dispersal into sensitive areas
what is bioremediation
1) some bacteria break down hydrocarbons to remove residual pollution
2) rate of bacterial action depends on environmental conditions
3) most rapid where temp and oxygen levels are high
4) bioremediation of soils can be increased by ploughing or irrigation
