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74 Cards in this Set
- Front
- Back
what is the ideal wastewater velocity in ft/s for grit removal in a grit chamber?
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1 ft/sec
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what is the water content of screened material?
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80%
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what is the wastewater velocity range in ft/sec for grit removal in a grit chamber?
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0.7 to 1.4 ft/sec
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which one of the following chemicals gives water its greatest capacity to neutralize acids?
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hydroxide
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the bar rack is used:
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when the bar screen is out of service
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what is the average detention time of wastewater in a primary clarifier?
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2 hours
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which one of the following gases is irritating to the eyes?
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chlorine
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activated sludge clarifiers accept material to be settled from:
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an aeration basin
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according to Clean Water Act, secondary treatmment is defined as a wastewater plant producing an effluent that has no more then __________ total suspended solids and no more that__________ BOD5.
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30 mg/L, 30 mg/L
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the color of the biofilm on rotating biological contactor would appear _____________ under normal operating conditions.
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gray
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a primary effluent and returned activated sludge mixture is called:
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waste activated sludge
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the mixture of organisms and solids in water that is removed from the settling tank is called:
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mixed liquor
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under normal operating conditions, what color is the activated sludge?
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dark chocolate brown
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what test could an operator use to make process changes immdiately if a problem develops?
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chemical oxygen demand (COD) test
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the main workers in the activated sludge process are:
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bacteria
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a yellow gas flame from a digester's waste gas burner may indicate a poor quality gas with a:
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high CO2 content
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ponds used in series after primary wastewater treatment are sometimes called:
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oxidation ponds
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the most common type of pond is:
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foculative 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?
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mosquitoes
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when is the dissolved oxygen in a waste pond the lowest?
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sunrise
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what would be mostlikely solution, if the influent to a wastewater treatment plant had an H2S odor?
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add treatment chemicals
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what is the main reason why wastewater treatment plants remove phosphorus from thier effluent before discharging to a lake or river?
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to reduce the growth of algae
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what is the color of liquid chlorine?
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amber
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how many times heavier than air is chlorine gas?
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2.5 times
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free available chlorine consists of:
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dissolved chlorine gas, hypochlorous asid, and hypochlorite ion
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the fusible plug on a chlorine cylinder will start to melt at approximately;
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160F
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the solids treatment usually has 20 days of retention time:
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aerobic digestion
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the solids treatment method usually has 20 days of retention time:
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aerobic degestion
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the solids treatment method processes solids in a sealed unit:
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anaerobic digestion
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the solids treatment method produces methane gas that can be used in other plant processes:
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anaerobic digestion
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this solids treatment method cures the final product and then it may be applied to farmlands:
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composting
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this soilds treatment method uses evaporation but also requires a great deal of labor:
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sand drying beds
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this solids treatment method uses a partially submerged rotating drum:
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vacuum filter
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these solid treatment methods use a coagulant polymer and pressure:
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belt filter and plate
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test such as ph, temp, and dissolved oxygen should always be performed within______after collection
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15 min
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when calibrating a ph meter, the buffers used should bracket the expected ph and:
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be at least 2 ph units apart
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a test method for determining dissolved oxygen is the:
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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 sulfric acid?
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8 hrs
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BOD5 samples can be preserved by:
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storiing them in fridge above freezing and up to 4c
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the maximum holding time for preserved BOD5 samples is:
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2 days
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which one of the following tests is least likely to effectively help an operator control a waste plant process?
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BOD5
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the maximum holding time for a preserved total suspened solids sample is:
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7 days
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the state regulatory body must be notified of all unusual or extraodinary discharges by telephone within:
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24 hrs
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the state regulatory body must be notified for any noncompliance that could adversely affect the states waters or that could endanger public health within:
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24 hrs
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electomotive force (emf) is also known as:
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voltage
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electron flow is measured in:
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amps
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what type of fuses would most likely be used to protect a meter?
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dual element fuses
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what class of fire involves electrical equipment?
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Class C
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when a permit is required to enter a confined space, who may sign the permit?
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entry supervisor
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which one of the following is a measure of a materials opposition to the flow of electric current?
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ohms
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what class of fire involves oil and grease?
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class B
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why is it essential to ventilate a valve vault before entry?
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remove dangerous gases
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the primary purpose of check valves is to prevent:
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water from flowing in two directions
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which one of the following infectious diseases is not transmitted by wastewater?
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the acquired immune deficiency when syndrone virus (AIDS)
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which one of the following gases is least likely to collect in below ground vault?
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carbon monnoxide
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when working in a manhole, your vehicle, whenever possible, should be placed:
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between the manhole and oncoming traffic
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OSHA requires that adequate protection, such as shoring, be place in any trench that is
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5 ft greater in depth
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in a trench ladders are required every:
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25ft
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how many ladders are required to be in a 5ft deep trench when six people are working down in the trench?
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six ladders
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which is not an essential ingredient for all ordinary fires?
a. ignition sourc b. fuel c. heat d. oxygen |
ignition source
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if some clothes are on fire, what class of fire is it?
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class A
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if some magnesium is on fire, what class fire is it?
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class D
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what is the minimum munber of people that should be on site working at a confined space site, where one is entering a manhole?
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3
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what type of fire extinguisher should be in a pump station?
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A-B-C chemical type
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what piece of laboratory glassware is primarily used to mix chemicals and measure approximate volumes?
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beaker
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the electric potenial between two points is measured in:
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volts
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what is the most common use today for a positive displacement pump?
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chemical feed pump
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which laboratory glassware will give the most accurate measurements of liquids?
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burettes
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which laboratory glassware is used for measureing volumes?
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graduated cylinders
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people working in and around wastewater must be immunized for:
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tetanus
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which one of the following laboratory tests has a zero holding time?
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chlorine residual
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water is used as a standard becuase it has unque properties and is readily available in its pure state. Which standard is used?
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kilogram
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what acids are formed when water reacts with nonmetal oxides?
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acid anhydrides
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which on of the following is nat a hydrate?
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sodium nitrate
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