Water Treatment Unit Processes

Unit processes

Water treatment unit processes are the distinct process steps in a water treatment plant.  For example filtration is one unit process, commonly used with chlorination which is a second unit process.

Water treatment unit processes list

A list of water treatment unit processes, ordered where possible from source to tap:

  1. Raw Water Storage
  2. Screening
    1. Bar screens
    2. Band screens
    3. Drum screens
    4. Microstrainers
  3. Flow control
  4. pH control & chemical dosing
  5. Flocculation & coagulation
    1. Mixing
    2. Coagulation
    3. Polyelectrolyte & coagulant aid use
  6. Clarification
    1. Sedimentation
      1. Grit channels
      2. Sedimentation basins
      3. Sludge blanket clarifiers
      4. Tube settlers / inclined plate / lamella clarifiers
    2. Floatation
      1. Dissolved Air Floatation
  7. Softening
  8. Stripping
  9. Oxidation
    1. Chlorine
    2. Ozone
    3. Chlorine dioxide
    4. Aeration/Oxygenation
    5. Advanced Oxidation Processes (AOPs)
      1. Fentons reagent (hydrogen peroxide/iron)
        1. Photo-Fenton
        2. Electro-Fenton
      2. Titanium dioxide/UV
      3. Hydrogen peroxide/UV
      4. Ozone/UV
      5. Titanium dioxide/Ozone
  10. Filtration
    1. Media filtration
      1. Depth filtration
        1. Rapid Gravity Filtration (RGF)
        2. Multi-media filtration
      2. Biological filtration
        1. Slow sand filtration
        2. Biological activated carbon
    2. Membrane filtration
      1. Micro-filtration (MF)
      2. Ultrafiltration (UF)
      3. Nano-filtration (NF)
      4. Reverse Osmosis (RO)
  11. Desalination
  12. Adsorption
    1. Activated Carbon
      1. Granular Activated Carbon (GAC)
      2. Powdered Activated Carbon (PAC)
    2. Zeolites
  13. Ion Exchange
  14. Disinfection
  15. Sludge treatment
    1. Thickening
    2. Dewatering
      1. Belt press
      2. Plate press
      3. Centrifuge
      4. Thermal drying
    3. Anaerobic digestion
    4. Disposal / beneficial use

These are water treatment unit processes used in the production of potable (drinking), process & ultrapure water for municipal and industrial uses.

We intend to keep the above list up to date, and hope to eventually produce articles on all processes in the list.  We are prioritising the writing of these articles by need, so please contact us if there is a unit process that you would particularly like to read about, or if there is a unit process missing from the above list.