October 2011, Vol. 23, No.10
Test your knowledge of fats, oils, and grease
True or False Questions:
- Fats, oils, and grease (FOG) can be classified as polar or nonpolar.
- Nonpolar FOG, which typically biodegrades easily, comes from animal sources; polar FOG, which is much less readily biodegraded, comes from petroleum products.
- When excess quantities of FOG enter the secondary treatment process and merge with biomass, settleability improves.
- Metalworking wastewater is typically de-emulsified at the metalworking facility before being discharged to the publicly owned treatment works.
Multiple Choice Questions:
Which of the following definitions best describes the term free oil?
A. OIl dispersed in water in a stable form as 5- to 20-µm droplets
B. Oil that is solubilized in liquid
C. Oil that adheres to the surface of solids
D. Oil present in water having little or no water associated with it
What’s the common name of U.S. Environmental Protection Agency Method 1664 A, which is used to measure FOG?
A. The n-Hexane Extractable Method
B. The Isopropyl Alcohol Immersion Method
C. The Cyclopentanone Refresh Method
D. The Cyclododecanol Addition Method
What’s the average concentration of FOG in domestic wastewater?
A. 1 to 10 mg/L
B. 10 to 25 mg/L
C. 30 to 50 mg/L
D. 75 to 80 mg/L
To prevent free FOG, which can be removed simply by skimming, from becoming emulsified FOG, which is difficult to remove, what should be avoided?
A. Pumping the oily water with a centrifugal pump
B. Letting the FOG-laden water stand for long periods of time
C. Adding deodorizing chemicals to the FOG-laden water
D. Adding flocculation chemicals
What device is most often used to separate a chemically concentrated FOG from water?
B. Dissolved air flotation unit
C. Belt filter press
Click here to show or hide the answer key
Questions were developed by Steve Spicer and reviewed by the Operations forum Editorial Advisory Board and the Association of Boards of Certification (Ankeny, Iowa) Wastewater Treatment Validation and Examination Committee.
Water Environment Federation (2008). Operation of Municipal Wastewater Treatment Plants; Manual of Practice No. 11, Fifth Edition. Alexandria, Va.: Water Environment Federation.
Water Environment Federation (2008). Industrial Wastewater Management, Treatment, and Disposal; Manual of Practice No. FD-3, Third Edition. Alexandria, Va.: Water Environment Federation.
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