November 2009, Vol. 21, No.11
Test Your Knowledge of Membranes
True or False Questions:
- Flux is the volume of water that passes through a membrane per unit of time and per unit of surface area of the membrane.
- Microfiltration and ultrafiltration remove impurities via diffusion and electrostatic exclusion.
- Cellulose acetate membranes are well suited to high-pH wastewaters.
- Membrane filtration systems typically function as the limiting hydraulic flow restriction in a wastewater treatment plant.
Multiple Choice Questions:
Which of the following choices is an advantage of a membrane bioreactor system?
A. Reduced downstream disinfection demand.
B. Availability of extensive long-term data.
C. Decreased potential for system foaming.
D. Ability to treat flows well above design specifications.
Where are turbidmeters often installed in a system to monitor membrane integrity?
A. In the biological process tank.
B. On the influent side of the membrane.
C. On the effluent side of the membrane.
D. In the effluent discharge flow.
What is the standard range of operating pressures for an ultrafiltration system?
A. 1–30 lb/in.2.
B. 3–80 lb/in.2.
C. 70–220 lb/in.2.
D. 800–1200 lb/in.2.
Which of the following choices is not a type of membrane element commonly used on wastewater treatment?
A. Flat sheet.
B. Hollow fiber.
C. Spiral-wound cylinder.
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Questions developed by Steve Spicer and reviewed by the Association of Boards of Certification (Ames, Iowa) Validation and Examination Committee.
Water Environment Federation (2006). Membrane Systems for Wastewater Treatment, New York: WEF Press/McGraw–Hill.