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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?
1 ft/sec
what is the water content of screened material?
80%
what is the wastewater velocity range in ft/sec for grit removal in a grit chamber?
0.7 to 1.4 ft/sec
which one of the following chemicals gives water its greatest capacity to neutralize acids?
hydroxide
the bar rack is used:
when the bar screen is out of service
what is the average detention time of wastewater in a primary clarifier?
2 hours
which one of the following gases is irritating to the eyes?
chlorine
activated sludge clarifiers accept material to be settled from:
an aeration basin
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.
30 mg/L, 30 mg/L
the color of the biofilm on rotating biological contactor would appear _____________ under normal operating conditions.
gray
a primary effluent and returned activated sludge mixture is called:
waste activated sludge
the mixture of organisms and solids in water that is removed from the settling tank is called:
mixed liquor
under normal operating conditions, what color is the activated sludge?
dark chocolate brown
what test could an operator use to make process changes immdiately if a problem develops?
chemical oxygen demand (COD) test
the main workers in the activated sludge process are:
bacteria
a yellow gas flame from a digester's waste gas burner may indicate a poor quality gas with a:
high CO2 content
ponds used in series after primary wastewater treatment are sometimes called:
oxidation ponds
the most common type of pond is:
foculative pond
which one of the following nuisance organisms is controlled simply by the water surface being disturbed by wind or currents?
mosquitoes
when is the dissolved oxygen in a waste pond the lowest?
sunrise
what would be mostlikely solution, if the influent to a wastewater treatment plant had an H2S odor?
add treatment chemicals
what is the main reason why wastewater treatment plants remove phosphorus from thier effluent before discharging to a lake or river?
to reduce the growth of algae
what is the color of liquid chlorine?
amber
how many times heavier than air is chlorine gas?
2.5 times
free available chlorine consists of:
dissolved chlorine gas, hypochlorous asid, and hypochlorite ion
the fusible plug on a chlorine cylinder will start to melt at approximately;
160F
the solids treatment usually has 20 days of retention time:
aerobic digestion
the solids treatment method usually has 20 days of retention time:
aerobic degestion
the solids treatment method processes solids in a sealed unit:
anaerobic digestion
the solids treatment method produces methane gas that can be used in other plant processes:
anaerobic digestion
this solids treatment method cures the final product and then it may be applied to farmlands:
composting
this soilds treatment method uses evaporation but also requires a great deal of labor:
sand drying beds
this solids treatment method uses a partially submerged rotating drum:
vacuum filter
these solid treatment methods use a coagulant polymer and pressure:
belt filter and plate
test such as ph, temp, and dissolved oxygen should always be performed within______after collection
15 min
when calibrating a ph meter, the buffers used should bracket the expected ph and:
be at least 2 ph units apart
a test method for determining dissolved oxygen is the:
azide modification of the Winkler titration method
how long can a dissolved oxygen sample wait for analysis using the modified Winkler method, if it is preserved with sulfric acid?
8 hrs
BOD5 samples can be preserved by:
storiing them in fridge above freezing and up to 4c
the maximum holding time for preserved BOD5 samples is:
2 days
which one of the following tests is least likely to effectively help an operator control a waste plant process?
BOD5
the maximum holding time for a preserved total suspened solids sample is:
7 days
the state regulatory body must be notified of all unusual or extraodinary discharges by telephone within:
24 hrs
the state regulatory body must be notified for any noncompliance that could adversely affect the states waters or that could endanger public health within:
24 hrs
electomotive force (emf) is also known as:
voltage
electron flow is measured in:
amps
what type of fuses would most likely be used to protect a meter?
dual element fuses
what class of fire involves electrical equipment?
Class C
when a permit is required to enter a confined space, who may sign the permit?
entry supervisor
which one of the following is a measure of a materials opposition to the flow of electric current?
ohms
what class of fire involves oil and grease?
class B
why is it essential to ventilate a valve vault before entry?
remove dangerous gases
the primary purpose of check valves is to prevent:
water from flowing in two directions
which one of the following infectious diseases is not transmitted by wastewater?
the acquired immune deficiency when syndrone virus (AIDS)
which one of the following gases is least likely to collect in below ground vault?
carbon monnoxide
when working in a manhole, your vehicle, whenever possible, should be placed:
between the manhole and oncoming traffic
OSHA requires that adequate protection, such as shoring, be place in any trench that is
5 ft greater in depth
in a trench ladders are required every:
25ft
how many ladders are required to be in a 5ft deep trench when six people are working down in the trench?
six ladders
which is not an essential ingredient for all ordinary fires?

a. ignition sourc
b. fuel
c. heat
d. oxygen
ignition source
if some clothes are on fire, what class of fire is it?
class A
if some magnesium is on fire, what class fire is it?
class D
what is the minimum munber of people that should be on site working at a confined space site, where one is entering a manhole?
3
what type of fire extinguisher should be in a pump station?
A-B-C chemical type
what piece of laboratory glassware is primarily used to mix chemicals and measure approximate volumes?
beaker
the electric potenial between two points is measured in:
volts
what is the most common use today for a positive displacement pump?
chemical feed pump
which laboratory glassware will give the most accurate measurements of liquids?
burettes
which laboratory glassware is used for measureing volumes?
graduated cylinders
people working in and around wastewater must be immunized for:
tetanus
which one of the following laboratory tests has a zero holding time?
chlorine residual
water is used as a standard becuase it has unque properties and is readily available in its pure state. Which standard is used?
kilogram
what acids are formed when water reacts with nonmetal oxides?
acid anhydrides
which on of the following is nat a hydrate?
sodium nitrate