class d

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  1. Name three toxic gases
    Hydrogen sulfide, Phosgene(mustard gas), Chlorine
  2. � What factors affect the alkalinity of a digester?
    • � 1.digester loading
    • � 2.toxicity
    • � 3.digester heating
    • � 4.digester mixing
    • � 5.gas system
  3. � What is a rotameter?
    Rotameter is used to indicate the rate of gas flow.
  4. � What part does the chlorine injector play in application?
    The injector operating water supply serves to produce the vacuum under which vacuum chlorinators function and to dissolve the chlorine and discharge it as a solution at the point of application.
  5. � Why is the volatile acid/ alkalinity relationship very useful in digester control?
    The volatile acid/alkalinity relationship is useful in digester control because it is the first indicator that the digestion process is starting to get out of balance and that corrective action is necessary.
  6. � What is the appearance of good activated sludge?
    brown, musty odor.
  7. � What is a critical period for dissolved oxygen?
    Low Flow and Hot Weather
  8. � What are Load Cells?
    Load cells are used to determine the bio-mass of a rotating biological contactor.
  9. � What is chlorine used for?
    Chlorine is used for disinfection, the killing of pathogenic bacteria.
  10. � What is the purpose of a universal joint?
    A universal joint is used on coupling units in case of misalignment.
  11. � What is the primary tank detention time?
    1-1/2 hours - 3 hours.
  12. � Why is phosphorus removal necessary
    phosphorus causes excessive growth of algae and weed, thus using up the available oxygen and depriving aquatic life.
  13. � What is the Kraus Process?
    It is a modification of conventional activated sludge process by the addition of nitrogenous material.
  14. � What is the purpose of a water seal on a pump?
    The water seal provides lubrication and keeps gritty material from entering the packing box.
  15. � What is a grab sample and when is it used?
    • � 1. a grab sample is a single sample of wastewater taken at neither a set time nor flow.
    • � 2. a grab sample is used for DO, coliforms, chlorine residual, temperature and pH.
  16. � What is the purpose of a baffle in a sedimentation tank?
    The baffle provides for even distribution of the wastewater
  17. � What does a decrease in SDI indicate?
    It indicates a less settleable sludge.
  18. � Explain contact stabilization?
    two aeration tanks are used, one for separate reaeration of the return sludge for at least four hours and the second one collects the aerated sludge and mixes it with primary effluent that needs treatment.
  19. � How can you control the concentration of suspended solids in the secondary system?
    You can adjust the recirculation rate or the flow pattern to the clarifier.
  20. � What does brown foam indicate on the surface of your Mixed Liquor?
    Old Sludge - brown with heavy scum indicates old sludge where as white with a soap suds appearance indicate young sludge.
  21. � What is the second stage of an anaerobic digester used for?
    It is used for solids settling.
  22. � What is the optimum operating temperature for an anaerobic digester?
    85 degrees to 100 degrees.
  23. � On a V-belt what does the letter indicate?
    the shape of cross sectional area.
  24. � If you had a CL2 leak in a cylinder how would you reduce the effect of the leak?
    rotate the cylinder so that the leak is located in the most upright position--so the gas will be at top and liquid on the bottom.
  25. � What test would you use to measure grit content?
    Total Volatile Solids
  26. � What effects do Copper and Chlorine (Cu or Cl2) have on BOD?
    They lower your BOD value.
  27. � What is the normal speed of a rotating Biological Contactor (RBC)?
    1-2 rev/min
  28. � If you have white foam on the surface of an aeration tank how to correct?
    lower you sludge return rate, white foam indicates young sludge lowering return rate will increase sludge age.
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class d

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