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35 Cards in this Set
- Front
- Back
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The length of time required for waste to reach your plant can affect treatment plant efficiency. T or F |
True |
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Ponds are frequently constructed in rural areas where there is sufficient available land. T or F |
True |
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The purpose of flow measuring devices is to treat wastes. T or F |
False |
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All primary clarifier, no matter what their shape, must have a means for collecting the settled solids and the floating solids. T or F |
True |
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Both the trickling filter and the activated sludge treatment processes are anaerobic biological treatment processes. T or F |
False |
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The activated sludge process is a biological process and it serves the same function as a trickling filter or rotating biological contactor. T or F |
True |
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Incineration or burial of skinnings from the clarifiers will prevent treatment plant operational problems. T or F |
True |
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Algae in ponds produce oxygen for the other organisms to use. T or F |
True |
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Both inductry and agriculture are discovering that treated effluent may be the most economical source of additional water. T or F |
True |
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Both aerobic and anaerobic sludge digestion processes produce stabilized or digested solids that ultimately must be disposed of in the enviroment. T or F |
True |
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What is a sanitary sewer? 1. A pipe or conduit(sewer) intended to carry wastewater or waterborne wastes from homes, businesses, and industries to the treatment works. 2. A separate pipe, conduit or open channel (sewer) that carries runoff from storms, surface drainage, and street wash, but does not include domestic and industrial wastes 3. A sewer designed to carry both sanitary wastewaters and stormwater or surface water runoff 4. The seepage of groundwater into a sewer system including service connections |
A pipe or conduit (sewer) intended to carry wastewater or waterborne wastes from homes, businesses, and industries to the treatment works |
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When are pump stations normally installed? 1. When low areas of land must be sewered or where pipe depth under the ground surface becomes excessive 2. When sewers need a break to allow for maintenance activities 3. When the handowners want a structure to blend in with the landscape 4. When wastewater must be treated before it reaches the treatment plant |
When low areas of land must be sewered or where pipe depth under the ground surface becomes excessive |
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How can fluctuating flows from a large pump station be reduced? 1. By controlling flows or discharges to the sewers at the source 2. By controlling the power input to the pump station 3. By installing valves in the influent sewers to the plant 4. By using variable speed pumps or short pumping cycles |
By using variable speed pumps or short pumping cycles |
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What is the purpose of flow measuring devices? 1. To freshen the wastewater and to help remove oils and greases 2. To measure and record pathogenic organisms entering the plant 3. To measure and record solids bypassing the solids removal processes 4. To measure and record the flow rates and volumes of wastewater treated by the plant |
To measure and record the flow rates and volumes of wastewater treated by the plant |
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What is the purpose of pre-aeration? 1. To freshen the wastewater and to help remove oils and greases 2. To measure and record flows 3. To remove settleable and floatable materials 4. To remove suspended and dissolved solids |
To freshen the wastewater and to help remove oils and greases |
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Why is treated wastewater disinfected before it is discharged to receiving waters? 1. To clean up the effuent before discharge 2. To freshen the watewater 3. To prevent the spread of disease 4. To remove settleable and floatable materials |
To remove settleable and floatable materials |
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Why are debris and trash usually removed from wastewater by a bar screen? 1. To bar wasterwater from causing odors while being treated 2. To collect debris and trash for recycling 3. To protect equipment and reduce any interferance with in-plant flow 4. To reduce maintenance on bar screens |
to reduce maintenance on bar screens |
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Why are most sewer pipes laid at a slope steep enough to maintain a wastewater flow of two feet per second (fps)(0.6m/sec)? 1. To ensure straight flow through manholes 2. To prevent grit from settling in the pipes 3. To prevent the release of odors and toxic gases 4. To provide sufficient cover to avoid breaking the pipe |
To prevent grit from settling in the pipes |
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Why should grit be removed early in the plant treatment process? 1. Because grit accumulates on the surface of clarifiers 2. Because grit is abrasive and will rapidly wear out pumps and other equipment 3. Because provides food for organisms in biological treatment processes 4. Because grit sticks to grease and forms grease balls |
Because grit is abrasive and will rapidly wear out pumps and other equipment |
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The exact amount of BOD removal in a clarifier depends on which factor? 1. The amount of BOD contained in the settled material 2. The amount of floatable grease removed from the clarifier 3. The procedures used to measure the BOD 4. The rate at which organism decompose organic matter |
The amount of BOD contained in the settled material |
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What happens when the clear surface water of the primary tank flows over the effluent weir at a high velocity? 1. Insufficient food (BOD) flows into the aeration tank 2. Particles settling to the bottom or those already on the bottom may be picked up carried from the tank 3. Re-aeration occurs and reduces the BOD 4. The tank empties too quickly |
Particles settling to the bottom or those already on the bottom may be picked up and carried from the tank |
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How is oxygen provided for the organisms living in the biological slime that grows o the RBC media? 1. The atmosphere surrounding the media 2. The blowers for the system 3. The diffusers in the bottom of the tank 4. The return or recirculated flows |
The atmosphere surrounding the media |
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What are the two major types of bacteria present in a digester? 1. Acid formers and gas formers 2. Aerobic and anaerobic 3. Fecal and E.coli 4. Methane and sulfide |
Acid formers and gas formers |
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Why must the effluent from plants in some areas be dechlorinated or detoxified before discharge to receiving waters? 1. To allow the application of precise chlorine doses for prechlorination 2. To avoid the release of chlorine odors 3. To protect aquatic life 4. To reduce chlorine tastes in the water |
To protect aquatic life |
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What is disinfection? 1. A process designed to kill or inactivate pathogenic organisms 2. The killing of all organisms 3. The preparation of water for drinking 4. The preparation of water for use in the laboratory |
A process designed to kill or inactivate pathogenic organisms |
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If hydrogen sulfide from the collection system reaches your plant, what impact could this have on the plant? 1. Additional gas could be available for heating 2. Concrete in the plant could be damaged 3. Industrial wastes could be masked 4. Odor problems could occur 5. The wastes could be more difficult to treat |
2, 4, 5 |
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When wastewater enters a treatment plant, it usually flows through a series of pretreatment or preliminary treatment processes including which processes? 1. Disinfection 2. Flow measurement 3. Grit removal 4. Screening 5. Shredding |
3, 4, 5 |
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Why must operators know the quantity of wastewater flow into a treatment plant? 1. To adjust aeration rates 2. To adjust chlorination rates 3. To adjust pumping rates 4. To calculate loadings on treatment processes 5. To calculate treatment efficiency |
all choices are correct |
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What are the disadvantages of using a weir to measure wastewater flows entering a plant? 1. A relatively dead water space occurs just upstream of the weir 2. As solids accumulate upstream of the weir, the flow reading may become incorrect 3. Odors and unsightliness can result from an upstream dead space 4. Organic solids may settle out upstream of the weir. 5. There is very little head loss during flow through the weir |
1, 2, 3, 4 |
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Which flow measuring devices are used to measure waste-water flows in pipelines? 1. Magnetic flowmeters 2. Orifices 3. Rotameters 4. Venturi meters 5. V-notch weirs |
Magnetic flowmeters and Venturi meters |
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Why are digestion tanks mixed continuously? 1. To allow the formation of supernatant 2. To avoid the formation of thick scum blankets 3. To bring the food to the organisms 4. To provide a uniform temperature 5. To return supernatant to the headworks |
2, 3, 4 |
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Scum blankets in a digester above the supernatant consist of which items? 1. Grease 2. Hair 3. Plastics 4. Rubber goods 5. Soap |
all of the above |
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Advanced methods of waste treatment are used to reduce which items from wastewater? 1. Last traces of organic materials 2. Nutrient content 3. Roots, rags, cans, and large debris 4. Sand and gravel 5. Settleable and floatable materials |
Last traces of organic materials and Nutrient content |
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Why do regulatory agencies require the disinfection of plant effluent prior to discharge? 1. To kill or inactivate pathogenic organism 2. To protect the receiving water that is used for a drinking water supply 3. To protect the receiving water that is used for hydroelectric power generation 4. To protect the receiving water that is used for navigation 5. To protect the receiving water that is used for swimming or wading |
1, 2, 5 |
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How can solids removed from wastewater by pretreatment processes be disposed of? 1. By centifuging and dewatering 2. By dewatering and then direct burial in a approved sanitary landfill 3. By digestion and then returning to the supernatant 4. By incineration with the remaining ash disposed of in a landfill 5. By mixing heating |
2, 4 |
