Part 1

• What are natural resources used for


  Food, timber, clothing, fuels
• Examples of natural resources: Cotton, wool, timber
• Examples of synthetic recourses: Plastic, polyester, acrylic
• What is sustainable development

  Meets the needs of current gen

  Doesn't compromise future gen
• Finite recourses def + example

  Recourses that will eventually run out

  Fossil fuels
• Renewable recourses def + example

  Recourses that wont run out

  Wood
• What is in pure water

  Water
• What is in potable water

  Water

  Low levels of salts

  Safe levels of harmful microbes
• What is in salty water

  Water

  High levels of salt

  (Can have) high levels of harmful microbes
• What is in fresh water

  Water

  Low levels of salt

  (Often) high levels of dangerous microbes
• To produce potable water


  1. Choose source of fresh water
  2. Filter it
  3. Sterilize it
• Desalination = Process to turn saltwater into potable water
• Methods of desalination

  Distillation

  Reverse osmosis
• Reverse osmosis

  Using membranes to separate the salts dissolved in water
• Reverse osmosis is expensive because: membranes, energy needed, and salty water corrodes the pumps
• Distillation process

  1. Heat sea water
  2. Sea water evaporates
  3. Sea water condenses into a new container
  4. Salt is left behind
• Sewage and agricultural waste contain organic matter and harmful microbes
• Industrial waste contains organic matter and harmful chemicals
• Treating sewage water: screening and grit removal

  Sewage passes through metal grit and filters out large objects
• Treating sewage water: sedimentation

  Sewage is left, solid sediments sink to bottom

  Sediment is called sludge

  Remaining liquid is called effluent
• Sludge contains:

  Organic matter

  Water

  Dissolved compounds

  Small solid particles
• Treating sludge: anaerobic treatment

  Bacteria added, breaks down organic matter anaerobically
• Treating sludge: how is biogas produced + what is itmade up of

  Anaerobic treatment produces biogas

  Biogas is a mixture of methane, carbon dioxide, and hydrogen sulfide
• Treatment of sludge: remaining sludge

  The remaining sludge can be dried out and used as a fuel
• Effluent contains?

  No visible solid matter but still some

  Contains harmful microbes
• Treating effluent: aerobic treatment

  Bacteria are added, they feed on organic matter and harmful microorganisms, break down matter by anaerobic respiration
• Treating effluent: bacteria removed

  Bacteria allowed to settle out of water
• Treating effluent: discharged

  Water is discharged into environment