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ENVS348 Review

  1. What is LS and how does it work?
    • Lime Softening
    • Removes hardness by precipitating it out of solution
  2. Lime
    Ca(OH)2
  3. Quicklime
    CaO
  4. Three reactions used in lime softening
    • 1. Ca(HCO3)2+Ca(OH)2-->2CaCO3(s)+2H2O
    • 2. Mg(HCO3)2+2Ca(OH)2-->2CaCO3(s)+Mg(OH)2(s)2H2O
    • 3. MgSO4+Ca(OH)2+Na2CO3-->Mg(OH)2(s)+CaCO3(s)+Na2SO4
  5. What process is used to remove permanent hardness?
    Lime-Soda Softening
  6. CLS
    Cold Lime Softening
  7. WLS
    Warm Lime Softening
  8. HLS
    Hot Lime Softening
  9. How do you remove silica from water?
    MagOx process. Add MgO to LS unit, silica will become trapped in heavy sludge blanket
  10. IX
    Ion Exchange
  11. How does IX work?
    Water passes through a packed cartridge that replaces hard ions with soft ions
  12. Types of ion exchange resins
    • -Anionic
    • -Cationic
    • -Neutral
  13. Classes of ion exchange resins
    • -SAC (Strong acid cation)
    • -WAC (Weak acid cation)
    • -SBA (Strong base anion)
    • WBA (Weak base anion)
  14. RO
    Reverse osmosis
  15. How does RO work?
    Pressure is applied to the concentrated water, which is then forced through a membrane. Contaminents are left behind.
  16. Permeate
    Treated water
  17. RO Parameters
    • Pore size - determines which TDS can be removed by RO
    • Flow rates - lower flow rates more efficient
    • Pressure - variable depending on application/membrane
    • Surface area - bigger SA is more efficient
  18. NF
    Nanofiltration
  19. UF
    Ultrafiltration
  20. In what order are these units placed in a water treatment plant?
    WLS-->IX-->NF/UF-->RO
Author
saitclt
ID
189028
Card Set
ENVS348 Review
Description
Unit Operations
Updated

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