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Water Environment & Technology (WE&T) is the premier magazine for the water quality field. WE&T provides information on what professionals demand:
cutting-edge technologies, innovative solutions, operations and maintenance, regulatory and legislative impacts, and professional development. |
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February 2008, Vol. 20, No. 2 |
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Certification Quiz
Test Your Knowledge of Pumps
True or False
1. T F When pumping wastewater, high points in the piping system should be vented to prevent accumulation of gasses that may reduce pump system capacity.
2. T F Impellers in induced vortex pumps are placed in such a way as to maximize impeller contact.
3. T F Open impellers, without a front or back shroud, are used mainly to pump wastewater that contains large solids.
4. T F The total energy required to lift wastewater from one level to another is called the velocity head.
5. T F Progressing cavity pumps can run dry without damage.
Multiple Choice
6. What type of pump is used for most wastewater pumping applications and some solids applications as well?
a. Rotary.
b. Centrifugal.
c. Electromagnetic.
d. Reciprocating.
7. What does the difference between the wire horsepower input to a pump and the brake horsepower delivered represent?
a. Pump friction.
b. Impeller resistance.
c. Water horsepower.
d. Energy loss in the motor.
8. Which pumps are typically used for thicker sludges with more than 4% solids?
a. Air lift pumps.
b. Centrifugal pumps.
c. Positive displacement pumps.
d. Metering pumps.
9. If a rotary lobe pump moving thickened secondary sludge that is 12% to 13% solids overheats, what is the proper corrective action?
a. Reduce sludge thickness to less than 9%.
b. Replace rotors.
c. Tighten belts.
d. Replace timing gears.
Questions were developed by Steve Spicer and reviewed by the Association of Boards of Certification (Ames, Iowa) Validation and Examination Committee.
Answer Key (Highlight box to reveal answers)
1. True.
2. False. Induced vortex pumps have impellers recessed in the volute chamber. These impellers induce a vortex to pull the liquid through the pump with minimal impeller contact.
3. True.
4. False. The total energy required to lift wastewater from one level to another is called the total dynamic head, which is the sum of the static head, velocity head, and friction losses in both the suction and discharge lines.
5. False. If a progressing cavity pump runs dry, the pump will be damaged in a matter of minutes. The suction piping must be arranged to keep the pump intake wet, or protective devices should be used.
6. b.
7. d.
8. c.
9. a. For rotary lobe pumps, sludge should not exceed 9% solids. |
Reference
Water Environment Federation (1996). Operation of Municipal Wastewater Treatment Plants; Manual of Practice No. 11, Fifth Ed. Alexandria, Va.: Water Environment Federation.
© 2008 Water Environment Federation. All rights reserved. |
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