c10 - using resources

• potable water is safe to drink, it is NOT pure
• potable water can be obtained from waste water, seawater or fresh water
• treating rain water :

  • filtration - solids are filtered out by passing through a mesh wire
  • sterilisation - microbes are killed with chlorine or uv light
• treating sea water :

  • distillation - boiling seawater creates steam which condenses to from pure water . OR...
  • reverse osmosis - selective membrane only allows water molecules to pass through. large molecules are separated from the water
• renewable resources are regenerated faster then they are used
• non-renewable resources are used up faster than they are regenerated
• waste water treatment:

  • screening - sewage is examined, grit and large items are removed
  • sedimentation - sewage is separated into heavier sludge and lighter effluent
• a low grade ore doesn't contain much metal
• phytomining:

  • plants growing o contaminated land absorb copper ions as they grow. the plants are harvested and burned to produce ash with copper compounds
• bleaching :

  • bacteria are added in low-grade ores. they break down the ores to create a copper-rich solution which we can extract copper from
• life cycle assessments asses all four stages of a products life cycle to try to calculate its total environmental costs
• life cycle : collecting raw maters ->making and packaging -> product use -> disposal
• paper bags are worse than plastic because they require more energy to make and they don't last long
• we ca reduce environmental damage by : reducing resource use, recycling materials or encouraging people to use them less
• corrosion describe the gradual destruction due to chemical reactions between metals and oxygen