waste water treatment

• What is potable water?

  Water that is safe to drink
• What are some uses of water besides drinking?

  Personal hygiene, flushing toilets, washing clothes
• What does wastewater contain?

  Organic molecules and harmful microorganisms
• What is the first stage of wastewater treatment?

  Sewage is screened through a mesh
• What is produced after sewage settles in sedimentation tanks?

  Liquid effluent and semi-solid sludge
• What happens to the sludge?

  It is digested by anaerobic bacteria
• What needs to be reduced in liquid effluent before discharge?

  Organic molecules and harmful microorganisms
• How are aerobic bacteria used in wastewater treatment?

  They digest organic molecules in the presence of oxygen
• Where can treated liquid effluent be safely discharged?

  Into nearby rivers or the sea
• What is a common industrial use of water?

  Making paper and chemicals
• What must be removed from industrial wastewater?

  Harmful chemicals
• What is done after harmful chemicals are removed from industrial wastewater?

  It enters general sewage treatment
• Is treated sewage used to produce potable water in the UK?

  No, it is not carried out
• What must be done to groundwater from aquifers before drinking?

  It needs to be treated with chlorine