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34 Cards in this Set
- Front
- Back
- 3rd side (hint)
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The normal velocity for wastewater flow through a velocity control grit chamber is? |
FPS - Feet Per Second |
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What is the color of fresh, raw, domestic wastewater? |
Gray |
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What is the hydraulic population equivalent conversion factor? |
100 gallons/ person/day |
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What is used to remove large, suspended solids from wastewater? |
Bar screen |
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What is the removal efficiency for a treatment process? If the influent BOD is 200 mg/L and the effluent BOD is 104 mg/L? |
48% (200-104) /200 = .48 * 100 |
(In + Out) / Out * 100 |
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A 10 inch diameter sewer pipe that is 215 feet long, will hold ( when completely full ) how many gallons of wastewater? |
891 3.14*.416*.416*215*7.48= |
3.14*R*R*L*7.48 |
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What is the velocity of wastewater that travels 300 feet in 50 seconds? |
6 fps 300/50 |
Distance/Time |
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What is the main cause of abrasion to pump impellers and operational problems in clarifiers? |
Grit |
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What is the best method of disposal for screenings removed from a wastewater plants bar screen? |
Landfilling |
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What is the primary disease caused by waterborne bacteria? |
Cholera |
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What is the primary disease caused by waterborne viruses? |
Hepatitis A |
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What is the maximum flow velocity in a gravity wastewater collection system? |
2 fps |
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What is the best description of raw, domestic wastewater? |
99.9% water and 0.1% solids |
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What is the incubation time for a BOD (biochemical oxygen demand) sample? |
5 days |
BOD5 Test |
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What is the organic population equivalent conversion in pounds of BOD per person per day? |
0.2 pounds |
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Of all the gases that may be found in a sewer manhole, what one is the most toxic to a human when inhaled? |
Hydrogen Sulfide |
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What would best describe grit in domestic wastewater. |
Inorganic Solids |
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What is the objective of primary treatment? |
Remove suspended solids. |
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What is the primary process in the secondary treatment process? |
Biological |
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What is the primary process in primary treatment? |
Physical |
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What is the minimum distance of the head on a V-notch weir? |
2.5 times the head of the weir. |
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What percentage range for efficient removal of BOD in primary treatment? |
25% to 35% |
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What is the primary problem that exists in an confined space with a high level of carbon dioxide? |
An improper oxygen concentration. |
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When hydrogen sulfide is present in a measurable quantity of a sewer manhole, where is it most likely to be found? |
Low in the manhole. |
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What are bacteria that cause disease in humans? |
Pathogenic |
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What gas is most likely to cause corrosion on metal and concrete surfaces in an aerobic wastewater treatment facility? |
Carbon dioxide |
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What is the detention time of an aeration basin that contains 2,400 cubic feet of water and has a daily flow of 0.175 MGD? |
2.46 hours 2400*7.48 / 175000/24 17,952/7,292 = 2.46 hours |
Cubic feet * 7.48 = Gallons of water. MGD * 1000000 / 24 hours in a day = GPD Gallons / GPD = Detention Time |
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What component of an atom orbits around the nucleus? |
Electron |
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What plant life form is necessary for a proper functioning waste stabilization pond? |
Green Algae |
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When will green algae add oxygen to the water? |
Only in the presence of sunlight. |
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What best describes what pH is a determination of? |
The hydrogen ion concentration. |
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If settled sewage has a pH of 6.5 , that means the sewage is? |
The sewage is acid. |
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What is the effect of adding calcium hydroxide to water? |
Increase the pH. |
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What is the most important factor that influences the amount of DO in a sample? |
The temperature of the sample. |
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