Waste Water Treatment

• Sewage treatment includes:

  1. screening and grit removal
  2. sedimentation to produce sewage sludge and effluent
  3. anaerobic digestion of sewage sludge
  4. aerobic biological treatment of effluent (liquid waste)
• Sewage and agricultural waste water require removal of organic matter and harmful microbes. Industrial waste water may require removal of organic matter and harmful chemicals
• 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 discharge
• Treated sewage is not directly used to produce potable water in the UK
• There are plenty of questions on wastewater treatment in the revision workbook