Water Pollution W9

Oil pollution

sources of oil to oceans

• transportation

• fixed installations

• produced water

• other sources

• natural inputs

transportation as a source

• tanker operations

  load on top

  segregated ballast system

  crude oil washing

• tanker accidents

  bilge + fuel oils

  dry docking

  non-tanker accidents

• tanker operations + shipping

fixed installations (source)

• coastal refineries

  offshore productions

  drilling

• marine terminals

produced water (source)

• when oil + gas produced - water within hydrocarbon reservoir brought to surface

• can make up >95% of produced liquids in some fields

• separated from hydrocarbons before either being reinfected into reservoir, or treated + discharged into sea

• permit required

other sources

• municipal wastes

• industrial wastes

• urban run-off

• river run-off

• atmospheric fall-out

• ocean dumping

Abiological weathering

 evaporation, dissolution, dispersion, photochemical oxidation, water-in-oil emulsification, adsorption onto suspended particulate material, sinking, + sedimentation

biological weathering

ingestion by organisms + microbial degradation

spread (oil slick)

• Thin film on surface of water

• 1 tonne of Iranian crude oil spreads to slick 48m diameter 0.1mm thick in 10 minutes

• Drifting occurs at 60% of water currents, 2-4% of wind speed

 

emulsification

• 'chocolate mousse'

• Can be 70-80% water

• 'thick pancakes' water

• 'sticky masses' land

• Small surface area of volume - degrades very slowly

• Oil in water emulsions - use of dispersants

dispersants

 have hydrophyllic end attaches to water + hydrophobic end attaches to oil, then get pulled apart

biodegradation

>90 strains of bacteria + fungi can biodegrade some components of pretoleum

mechanical reduction

tar balls- heavy residue of crude oil

cleaning up oil at sea

• dispersants

• booms

  towed booms at sea

  moored booms in shallow/inshore waters

• oil removal e.g., diggers

• slicklickers

  absorb surface oil from lakes, rivers, oceans + for absorbing oil in sumps, drains, bilges + under machinery

  made from sheep wool

bioremediation

• nutrient enrichment (bio stimulation)

  • addition of nutrients that limit degradation rates to spill sites

• seeding with naturally occurring microorganisms (bioaugmentation)

• seeding with genetically engineered microorganisms (bioaugmentation with GEMs)

little testing in field

difficult to draw valid conclusions due to time constraints in planning experiments with appropriate controls after a spill