Test Your Knowledge of Fats, Oil, and Grease

True or False
1. T  F  FOG can enter a plant as floating particles, emulsified material, or as a solution.

2. T  F  Nonpolar FOG, which is less readily degradable than polar FOG, typically comes from animal sources.

3. T  F  The same tests are used to detect FOG in wastewater as in sludge.

4. T  F  Very high FOG concentrations can lead to lower aeration needs.

Multiple Choices
5. If excessive levels of low-density FOG in a secondary system merge with the biomass, which of the following conditions can result?
a. Increased metals content.
b. Poor settleabilty.
c. Lower total suspended solids concentration in effluent.
d. Decreased mixing efficiency.

6. Which of the following are the keys to obtaining a representative sample for FOG testing?
a. Use a wide mouth glass jar and collect the sample from below the wastewater surface by grab-sampling techniques.
b. Use a wide mouth glass jar and collect the sample from the wastewater surface by grab-sampling techniques.
c. Jar material is irrelevant. The sample should be collected immediately downstream of a weir.
d. Use a wide mouth plastic jar and collect the sample from the wastewater surface using grab-sampling techniques.

7. If a WWTP’s only large industrial discharger is a large milk processor, what type of FOG should the plant be prepared to handle?
a. Vegetable.
b. Petroleum.
c. Animal.
d. None of the above.
 
8. How do high levels of free-floating animal or vegetable FOG prevent monitoring equipment from operating correctly?
a. By changing the conductivity of the water.
b. By capturing heat next to the probes.
c. By corroding the equipments electrical components.
d. By clogging or covering probe and sensor surfaces.

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

Answer Key (Highlight black box to reveal answers)

1. True. 2. False. Nonpolar FOG comes primarily from petroleum sources. 3. False. 4. False. Excessive amounts of FOG may interfere with aerobic and anaerobic biological processes and lead to decreased wastewater treatment efficiency. 5. b. 6. a. 7. c. 8. d.

References
Water Environment Federation (1996). Operation of Municipal Wastewater Treatment Plants; Manual of Practice No. 11, Fifth Ed. Alexandria, Va.: Water Environment Federation.

Water Environment Federation (1994). Pretreatment of Industrial Wastes; Manual of Practice No. FD-3. Alexandria, Va.: Water Environment Federation.

©2006 by the Water Environment Federation. All rights reserved.