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37 Cards in this Set
- Front
- Back
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What most likely causes a gasoline engine to overheat? |
Restricted air circulation |
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What does it mean if the sludge settles to 50mL out of 1 liter in five minutes for the settleability test on the mixed liquor of the aeration tank? |
More sludge should be wasted |
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Which one of the following is a major characteristic of waste from a bakery? |
Grease |
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What should an operator do first when he/she is starting a dissolved air floatation unit? |
Close all the drain lines from all the tanks, compartments, and the dump valves within the system |
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What will most likely be the result if the supervisor is not clear when assigning responsibilities to operators? |
Friction, misunderstanding, and inefficient work will result |
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Given the following data, how often should the bearings be greased? Data: A plant is equipped with a pump driven by a 100 HP, 1750 RPM electric motor. The pump operates about 20 hours per day. The motor has ball bearings which require periodic grease lurbrication. The bearing housing has a removable plug at the bottom and a grease fitting on the top. The motor operates in a relatively clean atmosphere. |
Every 4-6 months all the old grease should be expelled |
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What happens to the pH of a sludge sample taken from an anaerobic digester if it is left standing for an hour before running the pH test? |
The pH decreases |
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What does "NM 10-3" imprinted on an electrical wire mean? |
Nonmetallic sheathed, number 10 wire size, 3 conductor cable |
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What does pin floc in the final effluent from an aerated lagoon indicate? |
Excessive aeration |
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Which one of the following best describes a composite sampler? |
The sampler collects samples based upon flow and/or time |
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A gravity thickener is 20 feet in diameter. 200 GPM of primary sludge with 5% solids has been fed to the thickener and 120 GPM of 8% sludge has been removed. The thickener is septic. What should an operator do to correct the problem? |
Increase the withdrawal rate from the thickener |
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Given the following data, what is the mixed liquor volatile suspended solids? Data: Two aeration tanks, each 16 ft x 32 ft x 12 ft BOD: 163 mg/L Flow: 300,000 Gal/Day F/M ratio: 0.3 lbs of BOD/Lbs of MLSS |
1800 mg/L |
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What most likely causes filamentous "bulking" in the activated sludge process? |
Not enough nutrients and trace minerals within the influent |
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Who is repsonsible for building a public relations program within the plant? |
Top Management |
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Given the following data, what is the mean cell residence time (MCRT)? Data: Influent Flow: 3.5 MGD MLSS: 2850 mg/L Waste Sludge Flow: 0.08 MGD Total Secondary System Volume: 2.0 MG Waste Activated sludge SS: 6000 mg/L Final Effluent SS: 25 mg/L |
10 days |
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Which of the following most likely causes water hammer? |
Closing a valve too fast |
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A rapid sand filter has gone dry because the effluent valve was not closed tightly. After closing the effluent vavle, which valve should be opened slowly to refill the filter before restoring it to service? |
The wash water valve |
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What is the most important factor in preventing accidents at the wastewater treatment plant? |
The employment of a safety officer |
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What is the function of the F/M process control strategy for activated sludge? |
To maintain a balance between the amount of food entering the aeration tank and the mass of mircroorganisms in the aeration tank |
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Why should an operator check the groundwater level when he/she is draining the tanks for inspection? |
To make sure the groundwater is down far enough so the tanks will not float |
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Why is the media periodically flooded in trickling filters? |
To control trickling filter flies |
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Why must the horizontal pipes holding the air diffuser all be at the same elevation? |
To release air into the aerator evenly |
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Given the following data, what is the percent of volatile solids? Data: Sample: 100 mL Crucible Weight: 19.9850 g Crucible plus dry solids: 20.0503 g Crucible plus ash: 20.0068 g |
67% |
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Which of the following is an advantage of a gravity settling unit compared to a pressure floatation unit? |
Power Requirements are lower |
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Given the following data, what is the average sludge blanket concentration? (Concentrations are determined by the centrifuge method.) Data: Clarifier Volume: 700,000 Gals Aeration Tank Concentration: 3% solids Return Sludge Concentration: 12% solids Depth of sludge blanket: 8 ft Average Clarifier Depth:10 ft |
7.5 |
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Which one of the following is a major characteristic of wastes produced by a brewery? |
Dissolved, organic matter |
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What is nitrification? |
The conversion of ammonia to nitrates |
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What does an organizational chart show? |
The formal organization or the overall structure |
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What causes hydraulic overloading in a trickling filter? |
Too much recirculation |
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What should an operator do with a six-inch tear in the high density plastic used for rotating biological contractors (RBCs)? |
Repair it with heat fusion |
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How should the packing gland be tightened on a centrifugal pump? |
Tight enough to allow a steady drip of water to flow from the pump |
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What should an operator do if the sludge collecter mechanism is jerking, jumping, or stalling when the sludge blanket in the clarifier is not excessive? |
Dewater and inspect the clarifier |
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Given the following data, what is the volume of sludge produced by a final clarifier? Data:' Total Suspended Solids in the influent: 50 mg/L Total Suspended soids in the effluent: 5 mg/L The remaining sludge in the clarifier: 2% solids Sludge specific gravity: 1.025 |
293 CF/Million Gals |
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What is the purpose of a vacuum relief valve? |
To add air to the system |
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The average chlorine dose is 5 mg/L for an average daily flow of 0.4 million gallons. If chlorine costs 14 cents per pound, what will be the monthly cost? (Assume 30 days per month.) |
$70 |
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If an operator performs a residual chlorine test on the final effluent and gets a much deeper color than expected, what can he/she add to the sample to check the accuracy of the residual chlorine test if he/she suspects a false color? |
EDTA |
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What is the best type of flow measuring device for raw wastewater? |
Parshall Flume |
