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211 Cards in this Set
- Front
- Back
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What is the most common reason for a waste water to contain intermittent large amounts of sand, gravel, and grit? a. Groundwater infiltration b. Storm events c. Cement company discharges d. Refinery discharges |
b. Storm events |
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Combined waste water is defined as. a. Domestic wastewater and industrial wastewater b. Sanitary wastewater c. Domestic wastewater and stormwater runoff d. Sanitary wastewater and stormwater runoff |
d. sanitary waste water and storm water runoff |
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In general, the solids content in waste water is about? a. 0.1% b. 0.6% c. 1% d. 2.5% |
a. 0.1% |
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In general, what is the percentage of suspended solids in the total amount of solids? a. 30% b. 35% c. 45% d. 55% |
a. 30% |
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Generally, the percentage of dissolved solids in the amount of total solids is about? a. 45% b. 55% c. 65% d. 70% |
d. 70% |
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Which type of organisms would most probably be associated with poor treatment or young biomass? a. Amoebas b. Free swimming ciliates c. Rotifers d. Stalked ciliates |
a. Amoebas |
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Which type of organisms would most probably be associated with very clear plant effluent, low biochemical oxygen demand (BOD), and low amounts of suspended solids? a. Free swimming ciliates b. Stalked ciliates c. Amoebas d. Rotifers |
b. Stalked Ciliates |
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Aerobic bacteria will reproduce and live in an environment that contains only a. Hydrogen sulfide b. Oxygen c. Water d. Methane |
b. Oxygen |
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Anaerobic bacteria will reproduce and live only in an environment that completely lacks a. Free or dissolved nitrates b. Dissolved methane c. Dissolved hydrogen sulfide d. Free or dissolved oxygen (DO) |
d. Free or dissolved oxygen (DO) |
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The biochemical oxygen demand (BOD) test usually has a specific time of a. 2 days b. 3 days c. 5 days d. 10 days |
c. 5 days |
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An Imhoff cone measures a. Volume of settleable solids b. How fast sludge water will filter through a membrane c. Depth of transparency in a digester d. sludge carry over from a digester |
a. Volume of settleable solids |
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Septic conditions are caused by a. Fungi b. Molds c. Anaerobic bacteria d. Hydrogen sulfide accumulation |
c. Anaerobic bacteria |
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Scum is usually removed in the _______ treatment stage. a. Primary b. Secondary c. biological d. Chemical |
a. Primary |
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When domestic waste water enters natural waters, what species deplete most of the oxygen? a. Anaerobic bacteria b. Aerobic bacteria c. Protozoans d. Rotifers |
b. Aerobic bacteria |
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Once the oxygen is depleted in a natural body of water, which organisms take over? a. Flagellates b. Sporozoans c. Anaerobic bacteria d. Coliform bacteria |
c. Anaerobic bacteria |
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The major gas produced by anaerobic decomposition is a. Methane b. Carbon dioxide c. Nitrogen d. hydrogen sulfide |
a. Methane |
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Another name for primary treatments is a. Chemical treatment b. Sedimentation c. Grit removal d. Biological treatment |
b. Sedimentation |
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Digester gas is __________ when mixed with air in the proper proportions. a. Extremely toxic and moderately explosive b. Extremely explosive c. Slightly toxic and explosive d. Slightly explosive when there is an ignition source |
b. extremely explosive |
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A pond that is used to treat raw waste water is called a. An oxidation pond b. A facultative pond c. A waste stabilization pond d. A decomposition pond |
c. A waste stabilization pond |
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What is the angle of the bars on a manually cleaned bar screen? a. 25 degrees b. 30 degrees c. 33 degrees d. 45 degrees |
b. 30 Degrees |
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What is the angle of the bars on a mechanically cleaned bar screen? a. 30 to 45 degrees b. 40 to 45 degrees c. 45 to 60 degrees d. 50 to 60 degrees |
c. 45 to 60 degrees |
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What is the ideal waste water velocity in feet per second (ft/s) through a screen channel? a. 0.5 ft/s b. 1.0 ft/s c. 1.5 ft/s d. 2.0 ft/s |
c. 1.5 ft/s |
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what is the ideal waste water velocity in feet per second (ft/s) for grit removal in a grit chamber? a. 0.7 ft/s b. 1.0 ft/s c. 1.2 ft/s d. 1.4 ft/s |
b. 1.0 ft/s |
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A pond that has an aerobic top layer and an anaerobic bottom layer is called a. an oxidation pond b. a facultative pond c. a waste stabilization pond d. a decomposition pond |
b. A facultative pond |
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In general, what is the water content of screened material? a. 50% b. 65% c. 80% d. 89% |
c. 80% |
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What is the waste water velocity range in feet per second (ft/s) for grit removal in a grit chamber? a. 0.5 to 1.0 ft/s b. 0.7 to 1.4 ft/s c. 0.8 to 1.5 ft/s d. 1.0 to 1.5 ft/s |
b. 0.7 to 1.4 ft/s |
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Which one of the following chemicals gives water its greatest capacity to neutralize acids? a. Hydroxide b. Silicate c. Borate d. Phosphate |
a. Hydroxide |
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The bar rack is used a. When the bar screen is out of service b. Before the bar screen c. After the bar screen d. Either before or after the bar screen |
a. When the bar screen is out of service |
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Typically, what is the average detention time for waste water in a primary clarifier? a. 2 hr b. 3 hr c. 3.5 hr d. 4.5 |
a. 2 hr |
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Which one of the following gases is irritating to the eyes? a. Carbon monoxide b. Chlorine c. Methane d. hydrogen sulfide |
b. Chlorine |
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Activated sludge clarifiers accept material to be settled from a. An aeration tank b. A primary clarifier c. A Trickling filter d. A primary digester tank |
a. An aeration tank |
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According to the Clean Water Act, secondary treatment is defined as a waste water plant producing an effluent that has no more than ______ total suspended solids and no more than _____BOD5. a. 20 mg/L, 40 mg/L b. 30 mg/L, 30 mg/L c. 40 mg/L, 40 mg/L d. 40 mg/L, 20 mg/L |
b. 30 mg/L, 30 mg/L |
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The color of the biofilm on a rotating biological contactor would appear ______ under normal operating conditions. a. Dark green b. Greenish gray c. Gray d. Brown |
c. Gray |
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A primary efflent and returned activated sludge mixture is called a. Mixed liquor b. Mixed liquor suspended solids c. Activated sludge liquor d. Waste activated sludge |
d. Waste activated sludge |
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The mixture of organisms and solids in water that is removed from the settling tank is called a. Mixed liquor b. Mixed liquor suspended solids c. Activated sludge liquor d. Waste activated sludge |
a. Mixed liquor |
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Under normal operating conditions, what color is the activated sludge? a. Dark chocolate brown b. Light to medium brown c. Greenish brown d. Dark green |
a. Dark chocolate brown |
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What test(s) could an operator use to make a process changes immediately if a problem develops? a. BOD test b. Chemical oxygen demand (COD) test c. Sludge volume index (SVI) test d. Food to microorganism (F/M) ratio and percent volatile matter |
b. Chemical oxygen demand (COD) test |
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The main "workers" in the activated sludge process are a. Bacteria b. Protozoans c. Ciliates d. rotifers |
a. Bacteria |
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A yellow gas flame from a digester's waste gas burner may indicate a poor quality gas with a a. High CO2 content b. High H2S content c. High H2S and CO2 content d. High H2S and skatole content |
a. high CO2 content |
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Ponds used in a series after primary waste water treatment are sometimes called a. Secondary treatment ponds b. Tertiary treatment ponds c. Oxidation ponds d. Polishing ponds |
c. Oxidation ponds |
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The most common type of pond is a. An anaerobic pond b. An aerobic pond c. A facultative pond d. An oxidation pond |
c. A facultative pond |
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Which one of the following nuisance organisms is controlled simply by the water surface being disturbed by wind or currents? a. Mosquitoes b. Shrimp-like animals c. Dragonfly larvae d. Chironomid midges |
a. Mosquitoes |
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When is the dissolved oxygen in a waste pond the lowest? a. Sunrise b. Sunset c. Around noon d. Around 4:00 pm |
a. Sunrise |
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What would be the most likely solution, if the influent to a waste water treatment plant had a H2S odor? a. Airstream treatment b. Add treatment chemicals c. Remove sludge faster d. Improve housekeeping |
b. Add treatment chemicals |
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What is the main reason why waste water treatment plants remove phosphorus from their effluent before discharging to a lake or river? a. Because it seriously depletes oxygen b. Because it forms phosphoric acid that is detrimental to fish c. To reduce bacteria that can kill aquatic wilflife d. To reduce the growth of algae |
d. To reduce the growth of algae |
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What is the color of liquid chlorine? a. Yellow b. Yellowish green c. Green d. Amber |
d. Amber |
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How many times heavier than air is chlorine gas? a. 1.95 times b. 2.0 times c. 2.5 times d. 2.7 times |
c. 2.5 times |
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Free available chlorine consists of a. Hypochlorous acid and hypochlorite ion b. Hypochlorous acid, dissolved chlorine gas, and dichloramine c. Dissolved chlorine gas and hypochlorite acid d. dissolved chlorine gas, hypochlorous acid, and hypochlorite ion |
d. Dissolved chlorine gas, hypochlorous acid, and hypochlorite ion |
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The fusible plug on a chlorine cylinder will start to melt at approximately a. 145 F b. 150 F c. 155 F d. 160 F |
d. 160 F |
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This solids treatment method usually has 20 days of retention time: a. Lime stabilization b. Aerobic digestion c. Gravity thickening d. Thermal treatment |
b. Aerobic digestion |
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This solids treatment method processes solids in a sealed unit: a. Gravity thickening b. Solids concentrators c. Lime stabilization d. Anaerobic digestion |
d. Anaerobic digestion |
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This solids treatment method produces methane gas that can be used in other plant processes: a. Aerobic digestion b. Anaerobic digestion c. Chlorine oxidation d. Thermal treatment |
b. Anaerobic digestion |
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This solids treatment method cures the final product and then it may be applied to farmlands: a. Solids concentrators b. Composting c. Anaerobic digestion d. Flotation thickening |
b. Composting |
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This solids treatment method uses evaporation but also requires a great deal of labor: a. Sand drying beds b. Thermal treatment c. Gravity thickening d. Incineration |
a. Sand drying beds |
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This solids treatment method uses a partially submerged rotating drum: a. Centrifuge b. Vacuum filter c. Solids concentrators d. Aerobic digestion |
b. Vacuum filter |
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These solid treatment methods use a coagulant polymer and pressure: a. Solids concentrators b. Centrifuges c. Vacuum filters d. Belt filter and plate |
d. Belt filter and plate |
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Tests such as a pH, temperature, and dissolved oxygen should always be performed within_____ after collection. a. 15 min b. 30 min c. 1 hr d. 2 hr |
a. 15 min |
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When calibrating a pH meter, the buffers used should bracket the expected pH and a. Be no more than 2 pH units apart b. Be at least 2 pH units apart c. Be at least 3 pH units apart such as 4, 7, and 10 d. Be no more than 3 pH units apart |
b. Be at least 2 pH units apart |
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A test method for determining dissolved oxygen is the a. Iodometric direct titration b. Azide modification of the Winkler titration method c. amperometric direct titration d. Odzakovic titration method |
b. Azide modification of the Winkler titration method |
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How long can a dissolved oxygen sample wait for analysis using the modified Winkler method, if it is preserved with sulfuric acid? a. 2 hr b. 4 hr c. 6 hr d. 8 hr |
d. 8 hr |
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BOD5 samples can be preserved by a. Freezing b. Storing them in a refrigerator above freezing and up to 4C c. Adding 3 mL of 0.2N HNO3 d. Adding 2 mL of 0.2N H2S04 |
b. Storing them in a refrigerator above freezing and up to 4C |
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The maximum holding time for preserved BOD5 samples is a. 2 days b. 3 days c. 4 days d. 5 days |
a. 2 days |
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Which one of the following tests is least likely to effectively help an operator control a waste plant's process? a. DO b. pH c. Temperature d. BOD5 |
d. BOD5 |
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The maximum holding time for a preserved total suspended solids sample is a. 2 days b. 3 days c. 5 days d. 7 days |
d. 7 days |
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Generally, the state regulatory body must be notified of all unusual or extraordinary discharges by telephone within a. 1 hr b. 2 hr c. 24 hr d. 48 hr |
c. 24 hr |
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Generally, the state regulatory body must be notified for any noncompliance that could adversely affect that state's waters or that could endanger public health within a. 1 hr b. 2 hr c. 8 hr d. 24 hr |
d. 24 hrs |
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Electromotive force (emf) is also known as a. Voltage b. Ohms c. Watts d. Amps |
a. Voltage |
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Electron flow is measured in a. Watts b. Ohms c. Amps d. Voltage |
c. Amps |
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What type of fuses would most likely be used to protect a meter? a. Current limiting fuses b. Dual element fuses c. Phase fuses d. Voltage sensitive fuses |
b. Dual-element fuses |
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What class of fire involves electrical equipment? a. Class A b. Class B c. Class C d. Class D |
c. Class C |
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When a permit is required to enter a confined space, who may sign the permit? a. Attending person b. Entrant c. Entry supervisor d. Occupational Safety and Health Administration (OSHA) representative |
c. Entry supervisor |
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Which one of the following is a measure of a material's opposition to the flow of electric current? a. Volts b. Ohms c. Amperes d. Watts |
b. Ohms |
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What class of fire involves oil and grease? a. Class A b. Class B c. Class C d. Class D |
b. Class B |
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Why is it essential to ventilate a valve vault before entry? a. Equalize temperature and pressure b. Eliminate foul odors c. Remove excessive moisture d. Remove dangerous gases |
d. remove dangerous gases |
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The primary purpose of check valves is to prevent a. Loss of prime b. Excessive pump pressure c. Water from flowing in two directions d. Water hammer |
c. Water from flowing in two directions |
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Which one of the following infectious diseases is not transmitted by waste water? a. Tetanus b. Tuberculosis c. The acquired immune deficiency syndrome (AIDS) virus d. Polio |
c. The acquired immune deficiency syndrome (AIDS) virus |
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Which one of the following gases is least likely to collect in a below ground vault? a. hydrogen sulfide b. Gasoline Vapors c. Carbon dioxide d. Carbon monoxide |
d. Carbon monoxide |
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When working in a manhole, your vehicle, whenever possible, should be placed a. On the right side of the manhole b. On the left side of the manhole c. Ahead of the manhole and oncoming traffic d. Between the manhole and oncoming traffic |
d. Between the manhole and oncoming traffic |
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OSHA requires that adequate protection, such as shoring, be placed in any trench that is a. 3.5 ft or greater in depth b. 4 ft or greater in depth c. 4.5 ft or greater in depth d. 5 ft or greater in depth |
d. 5 ft or greater in depth |
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How far back from the opening of a trench should soil excavated from that trench be placed? a. 1 ft at least b. 2 ft at least c. 3 ft at least d. 4 ft at least |
b. 2 ft at least |
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In a trench, ladders are required every a. 10 ft b. 20 ft c. 25 ft d. 30 ft |
c. 25 ft |
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How many ladders are required to be in a 5 ft deep trench when six people are working down in the trench? a. one ladder b. two ladder c. three ladders d. six ladders |
d. six ladders |
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Which is not an essential ingredient for all ordinary fires? a. Ignition source b. Fuel c. Heat d. Oxygen |
a. Ignition source |
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If some clothes are on fire, what class of fire is it? a. Class A b. Class B c. Class C d. Class D |
a. Class A |
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If some magnesium is on fire, what class of fire is it? a. Class A b. Class B c. Class C d. Class D |
d. Class D |
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What is the minimum number of people that should be on site working at a confined space site, where one of them is entering a manhole? a. Two b. Three c. Four d. Five |
b. Three |
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What type of fire extinguishers should be in pump stations? a. Foam b. Carbon dioxide c. A-B-C Chemical type d. Water and carbon dioxide |
c. A-B-C chemical type |
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What piece of laboratory glassware is primarily used to mix chemicals and measure approximate volumes? a. Pipette b. Beaker c. Burette d. Graduated cylinder |
b. Beakers |
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The electric potential between two points is measured in a. Amperes b. Volts c. Ohms d. Watts |
b. Volts |
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What is the most common use today for a positive-displacement pump? a. Lift or booster pump b. Chemical feed pump c. Filter feed pump d. Wastewater water intake pump |
b. Chemical feed pump |
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Which laboratory glassware will give the most accurate measurements of liquids? a. Graduated cylinders b. Beakers c. flasks d. Burettes |
d. Burettes |
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Which laboratory glassware is used for measuring volumes? a. Flasks b. Beakers c. Graduated cylinders d. Burettes |
c. Graduated cylinders |
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People working in and around waste water must be immunized for a. Tetanus b. Cholera c. Amebiasis d. Dysentery |
a. Tetanus |
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Which on of the following laboratory tests has a zero holding time? a. Nitrate b. Chlorine residual c. Turbidity d. BOD5 |
b. Chlorine residual |
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Which one of the following statements concerning colloids is false? a. Solutes have a greater effect on freezing and boiling points of liquids than do colloids b. Only very small colloids will pass through a semipermeable membrane c. The average wavelength of white light is smaller than the dimensions of colloidal particles d. Dialysis is the separation of colloids from solutes through a semipermeable membrane |
d. Dialysis is the separation of colloids from solutes through a semipermeable membrane |
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Which one of the following statements concerning colloids is true? a. An ion opposite in charge to a colloidal particle will force its way into the colloidal particle b. Electrolytes will stabilize colloids c. Van der Waal's forces help stabilize colloidal particles d. Electrophoresis is a term used to describe the settling of a colloid in an electrical field |
a. An ion opposite in charge to a colloidal particle will force its way into the colloidal particle. |
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Water is used as a standard because it has unique properties and is readily available in its pure state. Which standard is not correct? a. Celsius scale b. The calorie c. The Kilogram d. Specific gravity |
c. The kilogram |
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What acids are formed when water reacts with a nonmetal oxides? a. Acid hydroxides b. Acid anhydrides c. Acid oxides d. Acid hydrates |
b. Acid anhydrides |
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Which one of the following is not a hydrate? a. Alum b. Blue stone c. Sodium nitrate d. Ferrous sulfate |
c. Sodium nitrate |
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An organism that does not require the presence of dissolved oxygen is called a. pathogenic b. aerobic c. anaerobic d. activated |
c. Anaerobic |
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A typical detention time for a septic tank would be about a. 3 days b. 1.5 days c. 12 hours d. 8 hours |
c. 12 hours |
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A treatment unit that allows sedimentation and digestion to take place in the same unit is a. An Imhoff tank b. A primary clarifier c. A grit chamber d. Sedimentation basin |
a. An Imhoff tank |
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What would be a typical detention time for a properly designed clarifier? a. 36 hours b. 24 hours c. 12 hours d. 2 hours |
d. 2 hours |
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What collects the sludge in a rectangular clarifier? a. Blades b. Plows c. squeegees d. Flights |
d. Flights |
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The ___________ provide for a uniformed removal of effluent from the clarifier surface a. Baffles b. Weirs c. Blades d. none of the above |
b. Weirs |
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Coagulants used in chemical treatment include a. Ferric chloride and lime b. Alum and chlorine c. polymers and hypochlorite d. all of the above |
a. Ferric chloride and lime |
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In chemical treatment, the flocculation process normally takes a. one hour b. two hours c. 15 to 45 mins d. 10 to 25 mins |
c. 15 to 45 mins |
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Clarifier efficiency is measured in a. mg/L b. % c. BOD d. D.T. |
b. % |
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Trickling filters, RBC's and activated are all ________ treatment processes. a. biological b. secondary c. temperature-dependent d. all of these |
d. all of these |
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Microorganisms are attached to a surface in the _______ treatment process. a. RBC b. Trickling filter c. Extended Aeration d. a and b |
d. a and b |
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How much clearance should be between the bottom of the distributor arm and the top of the bed of a trickling filter? a. 1 to 3 in. b. 6 to 9 in. c. 12 to 18 in. d. 24 in. |
c. 12 to 18 in. |
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Sludge in the bottom of a final clarifier at a trickling filter plant consists mostly of a. Floc b. Pathogens c. Humus d. Rock |
c. Humus |
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Odors and filter flies can often be prevented by a. Polymer b. Recirculation c. Effluent disinfection d. Heavy vegetation |
b. Recirculation |
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Aerators at an activated sludge plant provide a. Suspension of solids b. oxygen transfer c. Mixing d. All of these |
d. All of these |
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Rising sludge in an activated sludge plant final clarifier is commonly caused by a. Contact stabilization b. Kraus process c. Bulking d. Denitrification |
d. Denitrification |
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Filamentous bacteria in the mixed liquor may cause a. Bulking b. Nitrification c. Anaerobic conditions d. Denitrification |
a. Bulking |
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For a conventional activated sludge plant, the return sludge flow should be about a. 20% to 40% of influent flow b. 50% to 70% of influent flow c. half of the effluent flow d. none of the above |
b. 50% to 70% of influent flow |
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MLSS is measured in a. 1 lbs. of BOD b. PPM c. mg/L d. b and c |
d. b and c |
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Sludge blanket depth is controlled by a. influent flow b. RAS rates c. WAS rates d. All of the above |
d. All of the above |
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In a properly operating digester what is the major gas produced? a. Chlorine b. Sulfur dioxide c. Carbon dioxide d. Methane |
d. Methane |
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What is the % removal of solids in a primary clarifier? a. 25% b. 60% c. 80% d. 95% |
b. 60% |
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The pressure in forced mains is expressed as a. BTU b. GPM c. PSI d. RPM |
c. PSI |
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The ability of water to absorb dissolved oxygen is based on a. Temperature b. pH c. Turbidity d. None of the above |
a. Temperature |
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Finely divided solids that will not settle but may be used by chemical means are called a. Stragglers b. Colloidal c. Inorganic d. None of the above |
b. Colloidal |
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A valve used to permit flow in one direction only is a a. Ball valve b. Butterfly valve c. Gate valve d. Check valve |
d. Check valve |
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Sewage from households can be classified as a. Storm b. Industrial c. Domestic d. All of the above |
c. Domestic |
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The monitoring requirements for your plant are defined in a. Standard methods b. NPDES permit c. Public law 72-000 d. All of the above |
b. NPDES permit |
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What sampling method is used for determonation of MLSS? a. Grab b. Composite |
a. Grab |
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Groups of biomass that come together to form clusters in the activated sludge process are? a. Floc b. Mixed liquor c. Protozoa d. Aerobes |
a. Floc |
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What is organic matter? a. Leaves, sand, stone b. Fish, animal fats, plants c. Rags, flies, sugar d. None of the above |
b. Fish, animal fats, plants |
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A bulkhead with a notch in the end of a tank is called a. Parshall Flume b. Magmeter c. Weir d. Venturi tube |
c. Weir |
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Determine the volume in cubic feet of a tank 25 feet long, 17 feet wide, and 8 feet deep. |
(25ft)(17ft)(8ft)= 3,400 ft3 |
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Loading on a weir is expressed in a. PSI b. GPM c. GPD/Ft d. LBS/day |
c. GPD/Ft |
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The purpose of aerating activated sludge is to a. Provide oxygen to sustain living organisms b. Break larger particles into smaller ones c. To keep the food/mass ratio in balance d. None of the above |
a. Provide oxygen to sustain living organisms |
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What is the primary reason to return sludge from the secondary clarifier to the aeration tank? a. To exercise the return pumps b. To increase the detention time c. To increase the aerobic microbes d. None of the above |
c. To increase the aerobic mirobes |
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What is the best way to run a positive displacement pump to obtain even wear? a. Short stroke-slow speed b. Short stroke-fast speed c. Long stroke-fast speed d. long stroke-slow speed |
d. Long stroke-slow speed |
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What is the major advantage of a diaphragm pump over a centrifugal pump? a. Allows for pumping of heavier sludges b. Never needs to be cleaned out c. Must be operated by direct mechanical means d. None of the above |
a. Allows for pumping of heavier sludges |
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What chemical is fed into a sewer line to prevent H2S buildup? a. Hydrogen peroxide b. Sodium sulfite c. Alum d. None of the above |
a. Hydrogen peroxide |
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What color develops on the top of the media on a trickling filter? a. Brown b. Green c. Black d. Grey |
b. Green |
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The chlorine demand of your final effluent is 5 mg/L. How many ponds of chorine is necessary to treat 6 MGD? |
(5mg/L)(6MGD)(8.34)= 250.2 lb/day |
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You have a leaking chlorine cylinder at your plant. What should you do to the cylinder? a. Throw the cylinder into the clarifier b. You should do nothing. Let the Fire Dept. handle it c. Position the leak so that the gas will escape d. Spray it with a fire extinguisher |
c. Position the leak so that the gas will escape |
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The group of bacteria used to indicate the presence of pathogens in waste water is a. Plankton b. Filamentous c. Coli-boda d. Coli-aerogenes |
d. Coli-aerogenes |
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What is the reason for installing baffles at the influent of a clarifier? a. To prevent short-circuiting b. To reduce the flow c. Reduce skimmings d. None of the above |
a. To prevent short-circuiting |
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What is the detention time in a clarifier 90 ft. long, 30 ft. wide, and 12 feet deep. If the flow is 3.0 MGD? |
(90ft x 30ft x12ft) (7.48 gal/ft3)(24hr)= 5816448gal/hr 5816448gal/hr / 3MGD= 1.94 hrs |
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Grooves cut into pump shafts may be caused by a. Dirty seal and flushing water b. Wrong type of packing c. Glazed packing d. All of the above |
d. all of the above |
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What effect does temperature have on oxygen solubility? a. As temperature increases, dissolved oxygen increases b. Temperature has no effect on dissolved oxygen c. As temperature increases, dissolved oxygen decreases d. None of the above |
c. As temperature increases, dissolved oxygen decreases |
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The velocity over a weir in a grit channel is greater than 1ft/sec. why is this to be corrected? a. grit carry over can cause problems in equipment b. Grit takes up space in other treatment processes c, There is no problem, this condition is normal d. Both a and b |
c. There is no problem, this condition is normal |
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The term BOD is defined as a, Boss of the day b. Biochemical oxygen demand c. Biological oxygen demand d. Blanket of deapth |
b. Biochemical oxygen demand |
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At the first of the month a plant had 3734 lbs of HTH on hand. At the end of the month 49% had been used. How many lbs were used? |
(3734 lbs) (0.49) = 1829.7 lbs |
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You have a tank with a capacity of 2340 gal. It fills in 12 min. What is the flow in gal/min? |
2340 gal/12min = 195 gal/min |
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Alum is added to the treatment process to form? a. Floc b. Sludge c. Water d. Sulfuric acid |
a. Floc |
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A physical means of treatment at the plant is a. Activated sludge b. Alum flocculation c. Bar screens d. None of the above |
c. Bar screens |
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A major problem associated with operating an activated sludge plant is a. Bulking or floating sludge b. Odors c. Filter flies d. None of the above |
a. Bulking or floating sludge |
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In which process would you likely find an air diffuser? a. Trickling filter b. Clarifier c. RBC d. Aeration tank |
d. Aeration tank |
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What is the reason for having a secondary clarifier in a waste water treatment plant? a. To remove stone chips b. To remove large objects c. To remove settleable flocs d. all of the above |
c. To remove settleable flocs |
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What type of sample would you collect if you are going to perform the total suspended solids (TSS) test? a. Grab b. Composite |
b. Compostie |
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A pH reading of 7.0 in the final effluent indicates the sample is a. Acid b. Alkaline c. Neutral d. None of the above |
c. Neutral |
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Hydrogen sulfide gas smells like? a. Dead fish b. Flue gas c. Rotten cabbage d. Rotten eggs |
d. Rotten eggs |
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Why are gasoline and volatile solvents objectionable when present in a sewer? a. They produce an explosion hazard b. They tend to cause the solids to vaporize c. They coagulate floatables and cause stoppages. d. None of the above |
a. They produce an explosion hazard |
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The formula for calculating the volume of a wet well is a. v = L x W x cross section b. v = W x area x perimeter c. v = W x H x diameter d. v = L x W x depth |
d. v = L x W x depth |
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Biological activity in long, sluggish flow, flat grade sewer lines will likely cause a. concrete and metal corrosion b. oxygen deficiency an the air in manholes, sewers or wet wells c. toxic gas production d. all of the above |
d. all of the above |
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List five basic laboratory measurements used to determine clarifier efficiency. |
1. Settleable solids 2. Suspended solids 3. Total solids 4. BOD 5. Coliform group |
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About what percentage of settleable solids should you expect to be removed by your clarifier? |
95% to 99% |
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At what two points should samples be collected for measuring clarifier efficiency? |
Influent and the Effluent |
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What is the suspended solids removal efficiency of a primary clarifier if the influent concentration is 300 mg/L and effluent is 120 mg/L? |
Efficiency, %= (In-Out)/In (100%) =(300 mg/L - 120 mg/L)/300 mg/L (100%) = 60% |
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Tasks performed by a collection system operator include a. Cleaning local treatment plants b. Maintaining collection system equipment c. Making water connections d. None of the above |
b. Maintaining collection system equipment |
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One cubic foot per second flow is equal to ________ gallons per hour. a. 2794 b. 3600 c. 6000 d. 26928 |
d. 26928 |
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On floors where water or chemical are commonly spilled, cover floor with a. Catwalks b. Linoleum c. Tile d. Wood |
a. Catwalks |
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You should never attempt to install, troubleshoot, maintain, repair or replace electrical panels, controls, wiring or circuits unless a. A manhole is overflowing b, A pump is plugged c. You receive odor complaints d. You know what you are doing, are qualified, and are authorized |
d. You know what you are doing, are qualified, and are authorized |
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Employee hazards in collection system operations include a. Noxious or toxic gases or vapors b. Oxygen deficiency c. Physical injuries d. All of the above |
d. All of the above |
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GPM means gallons per a. Mile b. Milliliter c. Minute d. Month |
c. Minute |
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Leakage of seal water around the packing on a centrifugal pump is required because it acts as a(n) a. Adhesive b. Coolant c. Lubricant d. Vapor Barrier |
c. Lubricant |
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What must be checked before entering a manhole? a. Atmosphere in manhole b. Equipment c. Proper barricades or warning devises around manhole d. All of the above |
d. All of the above |
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In sewer maintenance, what is a PIG? a. A ball forced through a sewer line b. a power rod c. Any foul smelling equipment d. The hydraulic rodding truck |
a. A ball forced through a sewer line |
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The purpose of ribs on the outside of a wayne sewer ball is to a. Allow the ball's weight to be closer to the ball's center b. Avoid patent infringement c. Cause Jet action to aid in the hydraulic flushing of the sewer d. Reinforce (strengthen) the ball |
c. Cause Jet action to aid in the hydraulic flushing of the sewer |
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A pump is delivering at less than the expected rate of discharge. What will not cause this to happen? a. Check valve stuck or clogged b. Discharge head to low c. Impeller clogged d. Pump not primed |
b. Discharge head to low |
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Wearing rings are installed in a pump to a. Concentrate wear on an economically replaceable part b. Hold the shaft in position c. Keep the impeller in place d. Wear out rings instead of sleeves |
a. Concentrate wear on an economically replaceable part |
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A Lantern ring is a a. Metal ring used for lowering an explosive gas detector b. Shaft coupling that has been completely worn through in spots c. Spacer ring in a pump packing gland to improve seal water distribution d. Type of coupling for joining pipes |
c. Spacer ring in a pump packing gland to improve seal water distribution |
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Mechanical ventilation of a lift station is required to a. Lower temperatures to reduce production of hydrogen sulfide b. Reduce chlorine demand c. Reduce corrosion d. Increase D.O. in raw wastewater |
c. Reduce corrosion |
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To properly operate a power rodder a. Do not jam rodding tool into an obstruction b. Do not rotate the rod in one position for extended periods c. If a rod should break , make sure that the torque is out of it before handling it d. All of the above |
d. all of the above |
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Check Valves are used in connection with centrifugal pumps in order to a. Equalize the pressure on both sides of the impeller b. Prevent water in the suction line from flowing back into the reservoir c. Prevent water in the discharge line from flowing back d. Regulate the rate of water flow through the discharge pipe |
c. Prevent water in the discharge line from flowing back |
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While working in a manhole or a confined area, and you start feeling sick you should a. Get out of manhole b. Measure the oxygen level c. Measure the level of explosive gases d. Measure level of toxic gases |
a. Get out of the manhole |
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What information must be on a warning tag attached to a switch that has gbeen locked out? a. Directions for removing tag b. Name of nearest physician to call in case of an emergency c. Signature of person who locked out switch and who is the only person authorized to remove tag d. Time to unlock the switch |
c. Signature of person who locked out switch and who is the only person authorized to remove tag |
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Enclosed, open and semi-closed are terms used for designation and selection of a. Impellers b. Lantern rings c. Sleeves d. Stuffing boxes |
a. Impellers |
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What is (are) used to remove grease? a. Bar screens b. Biological treatment c. Chemicals d. All of the above |
c. Chemicals |
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A parshall flume is a type of a. Orifice b. Submerged nozzle c. Venturi d. Weir requiring free-fall discharge |
c. Venturi |
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Which of these chemicals should be used for odor control in sewers a. Chlorine b. Muriatic acid c. Potassium chloride d. Sodium chloride |
a. Chlorine |
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Which of the following are types of shores? a. Bar b. Hydraulic c. Truss d. All of the above |
b. Hydraulic |
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Important traffic safety considerations include a. Routine pedestrians around job site b. Routing traffic around job site c. Wearing of hard hats and safety vests d. All of the above |
d. all of the above |
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Which of the following actions would you perform first if an operator inhales chlorine gas? a. Immediately remove patient from contaminated area b. Immediately shut of all sources of chlorine c. immediately begin appropriate treatment d. Do nothing, as chlorine gas is non-toxic |
a. Immediately remove patient from contaminated area |
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Flatter sewer line grades may cause added sewer maintenance expense and odor nuisance. The problem most likely is caused by a decrease in velocity a. allowing gases to be released from the wastewater b. Allowing organic and inorganic solids to settle out in the lines c. Which increases the treatment time of the inorganic solids |
b. Allowing organic and inorganic solids to settle out in the lines |
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Sources of excessive clear water in a collection system include a. A problem at the wastewater treatment plant b. An interceptor sewer leak c. Exfiltration from a high water table d. Infiltration from a high water table |
d. Infiltration from a high water table |
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What items would you consider when selecting a solution to clear a stoppage in a sewer? a. Adding a solution to the upstream manhole to clear the stoppage b. Cause of stoppage c. Time of day d. Staffing requirements |
b. Cause of stoppage |
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Which of the following is not necessary to be done at the manhole with the completion of a sewer cleaning job? a. Load the debris on the truck b. sweep the debris around the manhole c. Wash down street around work area and machines, making sure the wash water is broomed into the manhole d. Wash down the truck |
d. Wash down the truck |
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Lift station failures include________ failure a. Dip tube b. Electrical circuit c. Inverted siphon d. All of the above |
b. Electrical circuit |
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a pH of 7.0 is a. Acidic b. Alkaline c. Neutral d. None of the above |
c. Neutral |
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The interior of 300 feet of 12 inch pipe is uniformly coated with one inch of grease. how many gallons will this pipe hold when filled with water? a. 1230 gallons b. 1360 gallons c. 1470 gallons d. 1630 gallons |
c. 1470 gallons |
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Infiltration is caused by a. Cracked pipes b. Improper closed circuit television operation c. poor ventilation d. All of the above |
a. Cracked pipes |
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The main reason for chlorinating wastewater in sewers is for ________ control a. BOD b. Odor c. Pathogen d. Suspended solids |
b. Odor |
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The most important reason for washing hands thoroughly after taking a wastewater sample is to a. Avoid being infected by pathogenic bacteria b. Avoid contaminating the BOD bottles c. Avoid smudging the BOD bottles d. Get the slime off your hands so you won't accidentally drop any glassware |
a. Avoid being infected by pathogenic bacteria |
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Roots can enter collection systems through a. Air gaps b. Manhole covers c. Pipe cracks d. All of the above |
c. Pipe cracks |
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Which of the following is a property of chlorine gas? a. Can be compressed into liquid form b. Harmless to humans c. Highly flammable d. Lighter than air |
a. Can be compressed into liquid form |
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Flushing sewer lines removes a. Grease b. Roots c. Heavy debris d. Light floatables |
d. Light floatables |
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The purpose of a lift station sign in log is to a. Budget lift station visits b. Identify who makes changes in station operation c. Track employee movement for disciplinary actions d. All of the above |
b. Identify who makes changes in station operation |
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What tools are used with a power rodder? a. Finger grips b. Pruning shears c. Spring blades d. Video tape camera |
c. Spring blades |
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The diameter of a wet well is 10 feet. If filled to a depth of 10 feet, it will contain approximately a. 2987 gallons b. 5875 gallons c. 6024 gallons d. 10602 gallons |
V= (3.14) r2 x h (7.48) v= (3.14)(5ft x 5ft)(10)(7.48) v= 5871.8 |
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Which one(s) of the following items should be inspected when responding to a lift station alarm at night? a. Amount of screenings and other trash removal b. Motor control center and power panel c. Operation of gas masks d. All of the above |
b. Motor control center and power panel |
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A solution with a pH of 6.0 is a. Acidic b. Alkaline c. Neutral d. None of the above |
a. Acidic |
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Areas subject to higher than normal vandalism are usually a. Along heavily traveled streets b. Secluded, out of the way buildings c. Well lighted, visible areas d. None of the above |
b. Secluded, out of the way buildings |
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Tools used for sewer rodding include all but the a. lag screw b. Porcupine c. Root saw d. Square bar cork screw |
a. Lag screw |
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How does an emergency service crew try to remove stoppage? a. Balling b. Flushing c. Hand rods d. Parachutes |
c. Hand rods |
