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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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September 2007, Vol. 19, No. 9 |
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Certification Quiz
Test Your Knowledge of Laboratry Practices
True or False
1. T F When using the DPD-chlorine method, a colorless or light yellow sample always means there is no chlorine present.
2. T F In general, biological activity reaction rates approximately double with every 10°C increase in temperature until higher temperatures begin to inhibit biological activity.
3. T F Turbidity measurements give the same results as suspended solids measurements.
4. T F To preserve a fecal coliform sample in a glass jar for analysis, cool the sample to 10°C.
Multiple Choice
5. In a wastewater setting, the results of a biochemical oxygen demand test indicate which of the following factors?
a. A measure of the ability of the wastewater to neutralize acid.
b. A relative measure of the amount of food material available to the biological system, degree of stabilization of the wastewater, and prospective effect of the effluent on the receiving water.
c. A measure of how much oxygen a sample will consume.
d. A measure of the ability of an aqueous solution to carry an electrical current.
6. Which of the following factors must be added together to find total solids?
a. Settleable and dissolved solids.
b. Settleable and nonsettleable solids.
c. Dissolved solids and nonsettleable solids.
d. Settleable, nonsettleable, and dissolved solids.
7. Which of the following actions is NOT needed to prevent biological fouling or alteration of a sample when using an autosampler?
a. Clean the sampling equipment and containers before the sampling event.
b. Analyze blanks on automatic sampling equipment to determine whether or not the equipment is causing contamination.
c. Reset the sampling equipment power supply before beginning sampling.
d. Ensure that sample collection bottles have been acid-washed (when appropriate) and rinsed with distilled water and dried before sampling.
8. After calculating what volume of sample will be needed to perform the required tests, what volume of sample water should be collected?
a. A volume equal to the amount needed for the tests.
b. A volume equal to the amount needed for the tests, plus an additional 50%.
c. A volume equal to the amount needed for the tests, plus an additional 100%.
d. A volume equal to the amount needed for the tests, plus an additional 150%.
9. What is the maximum holding time for a properly preserved COD sample?
a. 5 days.
b. 13 days.
c. 23 days.
d. 28 days.
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. False. At a near neutral pH, chlorine reacts with the DPD amine to form a stable, magenta-colored chemical, which gives the red color. But at higher oxidant levels, the formation of an unstable colorless imine is favored, resulting in the apparent “fading” of the colored solution.
2. True.
3. False. Turbidity does not directly correlate with suspended solids concentrations, because color can interfere with the turbidity measurement. However, it is easy to determine a relationship between turbidity and suspended solids for any given system. For instructions, see Chapter 17 in MOP 11 (full reference follows).
4. True.
5. b.
6. d.
7. c.
8. b.
9. d. |
References
Water Environment Federation (2006). Automation of Wastewater Treatment Facilities, Third edition; Manual of Practice No. 21. Alexandria, Va.: Water Environment Federation.
Water Environment Federation (1996). Operation of Municipal Wastewater Treatment Plants; Manual of Practice No. 11, Fifth Ed. Alexandria, Va.: Water Environment Federation.
©2007 Water Environment Federation. All rights reserved. |
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