water treatment 1

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  1. Particles of the greatest public health significance are___________ in size.
    Colloidal
  2. Conventional filters are NOT effective at removing particles of what size.
    Colloidal
  3. Suspended Particles are easily and effectively removed by ___________________
    Sedimentation and Filtration
  4. What war the three particle size categories
    Suspended, colloidal and Dissolved
  5. What characteristic causes colloidal particles to remain stable in water?
    Negative Surface charge
  6. 3 Primary Coagulants used
    • Aluminum Sulfate:     Al+++
    • Ferric Chloride:         Fe+++
    • Ferric Sulfate:          Fe+++
    • only last for about one second in the water
  7. Conventional Treatment 4 steps
    • Coagulation
    • Flocculation
    • Sedimentation
    • Filtration
  8. Charge Neutralization
    Apply positive charges to neutralize negative charges
  9. When a primary coagulant dissolves in water, it forms
    trivalent cations
  10. Sweep Coagulation
    • Uses the same Primary Coagulants as charge neutralization.
    • Forms sticky inorganic polymers that will physically adhere to colloids
  11. Sweep Coagulation 
    reaction
    React with alkalinity to form inorganic polymers - a chemical equivalent to biological mucus
  12. Sweep Coagulation requires and produces
    • Ten times more coagulant
    • Ten times more sludge
  13. What is the purpose of the coagulation process?
    Destabilization of Colloids
  14. What are the 2 mechanisms of coagulation?
    Charge Neutralization and Sweep Coagulation
  15. What is the most common chemical used for coagulation?
    aluminum Sulfate (Alum)
  16. Alkalinity
    Ability to resist decrease in pH
  17. Total Alkalinity =
    Hydroxide + Carbonate +  Bicarbonate
  18. buffering capacity
    Ability to resist change in ph
  19. Alkalinity neutralizes
    Hydrogen ions
  20. pH Scale
    0-14 7 is neutral
  21. Primary coagulants produce
    Hydrogen ions thus decreasing the ph of the water
  22. Primary coagulants combine with
    hydroxides, forming into inorganic polymers (floc)
  23. ph change is moderated by
    alkalinity which neutralizes hydrogen ions
  24. Do primary coagulants act as acids bases, or neutral substances?
    Acids
  25. what is the final chemical product in sweep coagulation with alum?
    Aluminum Hydroxide
  26. What are the three ions that make up total alkalinity in water?
    • Carbonate 
    • bicarbonate 
    • hydroxide
  27. common preoxidant
    • Chlorine
    • Ozone
    • Potassium Permanganate
    • Chlorine dioxide
  28. Preoxidation can yeild
    Microflocculation
  29. Polymers
    Long organic molecules that can link many colloidal particles together
  30. Most common Coagulant [polymer] Aid?
    Cationic polymer
  31. The mechanism by which polymers work is called?
    Polymer Bridging
  32. what is the most commonly applied chemical prior to coagulation?
    Chlorine
  33. Coagulation process components
    • Reaction chamber
    • Mixing system Chemical feeders
  34. charge neutralization must be completed
    • very quickly about one second
    • in-pipe section
  35. Sweep Coagulation time frame
    about one minute in a small mixing chamber
  36. chemical feeders are
    • positive displacement pumps
    • very accurate and controllable
    • Needed to match positive charges with negative colloids
  37. most effective way to add coagulation chemicals
    Pumped injection
  38. the most common chemical feeder for primary coagulation chemicals
    Positive Displacement pumps
  39. what is the term for the laboratory measurement of colloidal surface charge?
    zeta potential
  40. Laboratory procedure used to determine the optimum coagulant
    jar test
  41. Once colloids are destabilized what is the next treatment step?
    Increasing particle size with Clocculation

Card Set Information

Author:
 Hazard
ID:
 282856
Filename:
 water treatment 1
Updated:
2014-09-12 23:49:09
Tags:
water treatment
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Description:
water treatment terms and information
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