waste water treatment

    Cards (7)

    • Wastewater treatment
      1. Screening through mesh to remove solids and grit
      2. Sedimentation in tanks to produce liquid effluent and sludge
      3. Anaerobic digestion of sludge to produce biogas
      4. Aeration of liquid effluent to allow aerobic bacteria to digest organic matter and microorganisms
      5. Discharge of treated liquid effluent to environment
    • Wastewater contains large amounts of organic molecules and harmful microorganisms that need to be reduced before being released back into the environment
    • Treated sewage can be used directly to produce potable water, but this is not carried out in the UK
    • Sources of potable water
      • Groundwater from aquifers
      • Saltwater
      • Wastewater
    • Groundwater from aquifers
      • Usually safe to drink once treated with chlorine
      • Can be polluted e.g. with fertilizers
    • Saltwater
      • Needs to be desalinated to produce potable water
      • Desalination requires a lot of energy and is expensive
    • Wastewater
      • Requires many purification steps to produce potable water
      • Only done in places where water is scarce