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76 Cards in this Set
- Front
- Back
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What is pressure head caused by:
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Water elevation
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What color should the piping be that contains reclaimed water?
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purple
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What is the term for the height to which a column of water will rise in a well?
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piezometric surface
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What is the maximum practical lift of pumps?
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15 - 25ft
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Which one of the following valves is best to use in throttling flow situations?
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globe
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Which one of the following devices is used to measure water depths in storage facilities?
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transducer
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the velocity in sanitary sewers is approximately:
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2ft/s
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The distance between manholes ranges from:
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300 - 500ft
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What should the flow velocity be through a grit channel?
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1.0ft/s
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Grit washers are used to:
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remove some of the organic matter
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The most common flow measuring device for wastewater is a:
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Parshall Flume
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The detention time for primary clarifiers usually has a range of:
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1.5 - 2hrs
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The effluent from which process is called mixed liquor?
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activated sludge
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Aerobic ponds usually range in depth from:
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3 to 6ft
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Anaerobic ponds usually range in depth from:
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8 to 12 ft
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Another name for a waste stabilization pond is:
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raw wastewater lagoon
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What average percent of total solids in domestic wastewater, both dissolved and suspended, are organics?
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50%
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What average percent of total solids in domestic wastewater, both dissolved and suspended are inorganics?
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50%
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Approximately what percent of the dissolved solids in wastewater organics?
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87%
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Which type of oranisms would most probably be associated with moderate sludge age and effluent water quality?
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12%
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Which type of organisms would most probably be associated with moderate sludge age and effluent water quality?
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free swimming ciliates
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Which type of organisms would most probably be associated with high suspended solids and biochemical oxygen demand (BOD)?
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amoebas
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High suspended solids and BOD are most probably assoiciated with which type of oransims?
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flagellates
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Which type of organism would most likely enhance the penetration of oxygen into the activated sludge?
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rotifers
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Chlorine gas has a specific gravity of:
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2.5 sp gr
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Proper flow velocity through a grit channel is indicated when the grit being removed contains:
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a little organic material
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Surface loading and detention time in a clarifier are directly related to:
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flow through the clarifier
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What is the expected range for the removal of settleable solids from a primary clarifier?
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95 - 99%
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What condition will occur if sludge is not pumped out of primary clarifiers at regular intervals?
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clarifier will become septic
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Secondary clarifiers are usually located after:
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a biological process
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filter sloughings are a product of:
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biological action
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When one liquid is dissolved in another liquid it is called:
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an emulsion
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What is the optimum temp for digester substances?
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90F
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Which one of the following types of wastewater pounds listed below is not classified like the other three?
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aerobic pond
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What type of pond would recieve wastewater from a secondary treatment system?
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polishing pond
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The color of the biofilm on rotating biological contactor undergoing nitrification would appear:
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reddish brown to golden
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The color of the biofilm on a rotating biological contactor that has high sulfer concentrations would appear:
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chalky white
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Rotating biological contactors have all the following advantages except:
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high sludge production
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A wastewater plant has a train of three rotating biological contactor (RBC) units. The color of the first RBC is ___; the color of the second RBC is ___; and the color of the third RBC is ___.
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1 gray
2 reddish brown 3 reddish brown |
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Which one of the following activated sludge process modifications is very sensitive to bulking?
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conventional modification
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Which modified activated sludge process does not require primary treatment?
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contact stabilization
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Primary treatment is not required in which modified activated sludge process?
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extended aeration activation sludge
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Mixed liquor is a combination of the following mixture:
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activated sludge in an aeration tank mixed with primary effluent and return sludge or raw wastewater
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In a small package wastewater treatment plant, the operator should try to keep the dissolved oxygen in the aeration tank at approximately:
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2.0mg/L
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How much of the solids should be wasted each week in the summer from a package wastewater treatment plant for the best water quality?
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5%
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At what concentration level should dissolved oxygen be maintained during the initial startup of an oxidation ditch?
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2.0mg/L
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What should be the color of an oxidation ditch that is working properly?
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medium brown to dark brown
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Which one of the following is the least important in the successful operation of an activated sludge plant?
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BOD
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What is the critical factor in any method to control the aeration tank?
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F:M ratio
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What is the most accurate measure of the organisms present in an aerator for treating incoming wastes?
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MLVSS (mixed liquor volitile suspended solids)
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Most algae are in the:
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protista kingdom
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Bacteria are in the:
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monera kingdom
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Grease should be cleaned from walkways with a stiff brush and:
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trisodium phosphate
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Which one of the following types of substance is not soluble in water and has the potential of creating explosive conditions?
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flammable oils
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Which one of the following types of substances can cause obstructions in the sewer system and may cause anaerobic decomposition where the substances accumulate?
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settleable solids
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Which one of the following types of substances is corrosive and may interfere with biological treatment?
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acids and alkalies
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Which one of the following types of substances can be toxic to wastewater plants using biological systems and may adversely affect potable water supplies downstream?
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heavy metals
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Where would toxicants least likely cause a problem for a wastewater treatment plant?
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clarifier
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If an activated sludge plant is hit with a high organic load, what will most likely occur in the aeration tank?
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there will be a significant decrease in DO
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In the following list, which is the least important nutrient in wastewater treatment for microorganisms to reproduce?
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potassium
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Adequate BOD/nitrogen/phosphorus ratio for microorganisms to grow is usually:
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100:5:1
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Humus sludge is biomass from:
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trickling filters
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Excessive slime growths on a trickling filter may cause a conditionon the filter called:
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ponding
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Another name for slime growth is:
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zoological film
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It is not recommended to start up trickling filters in the ___ because bacteria are most often dormant at this time.
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winter
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When the influent load to a wastewater treatment plant changes rapidly, the best test for control purposes is:
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COD
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A problem with odors from trickling filters may be solved by:
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using masking agents
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What can be done to the trickling filter to solve high effluent suspended solids?
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decrease recirculation
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Approximately how much surface area of a rotating biological contactor is immersed in the wastewater?
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40%
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How many stages are usually present in the rotating biological contactor process?
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four stages
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Rotating biological contactors are adversely affected by temperatures below:
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55%
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How often should the oil be changed in the speed reducer of a rotating biological contactor?
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every 6 mths
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How often should the motor bearings be greased in a rotating biological contactor unit?
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every 12 mths
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How often should the mainshaft bearings be greased in a rotating biological contactor unit?
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every week
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How often should the drive bearings be greased in a rotating biological contactor unit?
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every week
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How often should the oil in the chan casing be changed?
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every 3mths
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