December 2006, Vol. 18, No.12

Certification Quiz

Test Your Knowledge of Membrane Systems

    True or False Questions:
  1. Flux is defined as the volume of water that passes through a membrane per unit of time and per unit of surface area of the membrane.
  2. A membrane bioreactor is a combination of an activated sludge treatment system and membrane filtration equipment, which performs the solid–liquid separation traditionally accomplished using secondary clarifiers.
  3. There is only one kind of membrane system that can be used in an MBR.
  4. Microfiltration and ultrafiltration membranes used for post-secondary filtration typically reject all suspended solids, provide 3 to 6 log removals of bacteria, reduce BOD by at least 95%, and greatly reduce turbidity.

  5. Multiple Choice Questions:
  6. Which of the following choices best defines permeability? 

  7. A. The ability of a membrane barrier to allow the passage or diffusion of a substance.
    B. The percentage of feed that is converted to permeate in direct filtration applications.
    C. The potential energy difference between two solutions separated by a semipermeable membrane.
    D. The difference between the average feed–concentrate pressure and the permeate pressure.

  8. What is the name of the condition when contaminants accumulate inside the pores of a membrane to the point where flux is reduced? 

  9. A. Macrofouling.
    B. Molecular weight cutoff.
    C. Microfouling.
    D. Size exclusion.

  10.  Which classification of membrane system removes dissolved salts and metal ions?

  11. A. Macrofouling.
    B. Molecular weight cutoff.
    C. Microfouling.
    D. Size exclusion.

  12.  Using the following data, calculate the percent recovery for the membrane filter described.

    Feed flowPermeate flowMembrane surface areaTemperature
    250 L/min228.3 L/min10.0 m222°C

  13. A. 99.3%
    B. 91.3%
    C. 92.7%
    D. 89.5%

Questions were developed by Steve Spicer and reviewed by the Association of Boards of Certification (Ames, Iowa) Validation and Examination Committee.

Answer Key:
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Water Environment Federation (2006). Membrane Systems for Wastewater Treatment. New York: WEF Press McGraw-Hill.