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30 Cards in this Set
- Front
- Back
The greatest activity and the highest BOD(biochemical oxygen demand) removal in a facultative lagoon will occur when there is: |
Good sunlight Warm temperatures Moderate breeze |
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What two actions take place on a drying bed? |
Evaporation & Filtration |
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When organic wastes are discharged to receiving waters, oxygen is depleted by: |
Bacteria |
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Artificial respiration must be started on a non-breathing casualty within: |
4 minutes |
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Dangerous gases most likely encountered in the wastewater industry are: |
Carbon monoxide, methane, hydrogen sulfide |
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What pH reading indicates an acidic wastewater? |
3. 0-6:Acidic 7: Neutral. 8-14: Basic alkaline |
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Which of the following is not a method of biological treatment? |
Primary settling |
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Before free chlorine can exist as a residual: |
Micro organism kill must be complete |
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The correct reason for upstream chlorination of a sewer is: |
Oxidizes H2S, Reduces odors, Reduces bacteria |
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At what time of the day is the DO(dissolved oxygen) content highest in a facultative lagoon? |
3 PM |
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Weir overflow rate in settling tanks is expressed in what units? |
gpd/ lineal ft |
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What is the main purpose for adding oxygen to an aeration tank? |
Keeps bacteria alive |
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Domestic wastewater consist of: |
Industrial & Domestic |
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What is reduced in the digester? |
Total & Volatile solids |
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An example of aerobic treatment is: |
A trickling filter |
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Chlorine residual is: |
Dosage minus demand |
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Centrifugal pump parts include: |
An impeller |
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________ indicates a good quality domestic activated sludge? |
Brown color & musty odor |
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What is the difference between the chlorine demand and the chlorine used? |
Residual |
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What happens when sludge bulking occurs? |
More suspended solids will flow over the weir |
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Sludge volume index indicates: |
ml occupied by 1 gm of sludge |
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The highest concentration of algae growth in a facultative lagoon is usually: |
Near the top |
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What test measures the strength of wastewater? |
BOD(biochemical oxygen demand) |
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In a centrifugal pump, internal leakage is prevented by: |
Wear rings |
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The normal BOD(biochemical oxygen demand) removal efficiency of an activated sludge plant is: |
90% to 98% |
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A water seal on a pump serves a dual purpose. It acts as a lubricant and: |
Acts as a coolant to keep the pump bearing from overheating |
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What is the purpose of a bubbler control system? |
To indicate the level in the tank |
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What is happening if you have a good collection system and your plant has an increase in the amount of grit removed? |
Broken sewer pipes in the collection system |
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_____ is the form of plant life that is necessary for the proper functioning of a stabilization or oxidation pond? |
Algae |
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Adding chemicals and slowly mixing over a long period of time to distribute the chemicals is: |
Flocculation |