Equipment O & M Flashcards
Which is a principal problem associated with
preliminary treatment screening?
Clogging
Particle counters use the principle of light ________.
Blockage
How much time does it usually take to slake lime in
the detention-time lime slaker?
20 to 30 minutes
At which temperature should the slaking process be
maintained?
1600 F or higher
Fixed screens or bar screens usually have openings
ranging from _______.
1 to 3 inches
Which is the simplest instrument for measuring levels?
Float-type sensor
Electricity is the study of the movement that effects
large numbers of _______.
Electrons
How often should chlorine supply lines
be replaced?
Every year
Which is the most common well
operational problem?
Plugging of the well screen
Bar screen assemblies are installed in a waterway at
a _______ angle from the horizontal.
600 to 800
Auxiliary equipment for Fluoridation includes?
A flow meter for measuring total flow such that
pacing can be provided.
Screen opening in raw water intakes are designed
for flows of ________.
2 ft/sec
If chlorine is added before the water enters the microstrainer,
what will occur?
Free chlorine may corrode the mesh.
Which chlorine gas feeder can also feed liquids?
Induction mixer
The voltage rating on a fuse should be ________ the
voltage of the circuit on which it is applied.
equal to or greater than
The streaming current detector is based on what principle?
Electromotive principle
Which does the streaming current detector actually
measure for determining the effectiveness of the
coagulant chemical?
Electrical resistance
What is the norman rotational speed of a
microstrainer?
5 rpm
Which metal has the highest corrosion potential?
Aluminum
Which flow measuring device is mechanical?
Loss of head meter
Which is the last step in well construction?
Pump test to confirm capacity.
Aspiration is the removal of?
Fluid from a container by suction.
Which is the best material to use for fittings, lighting, and ventilation systems in a room that houses an ammonia
hydroxide tank?
Stainless Steel
Wire size is selected according to which criteria?
Number of amperes to be carried.
Field experience has shown that streaming current detectors
require very intensive maintenance at water plants utilizing
treatment chemicals containing?
Iron salts
Grease that is water resistant is made with _______.
Calcium
Which type of continuous control action when signal is lost?
Floating proportional control
Which method for measuring water levels has a distinct
disadvantage where freezing occurs?
Float-type sensor
Which is the general test period to confirm design capacity
for a public water supply well that is in an unconfined aquifer?
At least 72 hours
Volumetric feeders are less expensive to maintain
than _________.
Gravimetric feeders
Which type of continuous control requires meters,
transmitters, and transducers?
Feedback control
Which type of continuous control has a controller that
constantly tries to change the output if there is deviation
from the set point?
Proportional plus reset control
In fluorid saturator tanks, the chemical should be at
least ________ deep at all times, and if the saturator
treats more than 100 gpm, it should have a chemical
depth of at least ________.
- 6 inches
- 10 inches
What metal can be used as an anode because
it is most active?
Mild steel
A poor conductor of electricity would
be _______.
deionized water
Destruction of pathogenic organisms by chlorine is
directly related to _________.
chlorine concentration
and
contact time.
How often should screen equipment be inspected
for corrosion?
Monthly
What disinfection treatment requires a monitoring
procedure, other than residual monitoring, to
determine its efficiency?
Ultraviolet
A pressure-differential meter is a flow-measuring device
that creates and measures a difference in
pressure ________ to the rate of flow.
proportional
What is the most dificult and the most expensive
physical measurement taken in a water plant?
Water flow
Most Fluoride dry feeders for large plants should have
a vibrator to prevent __________.
bridging
What disinfectant oxidant could have some
THM formation?
Chloramines
What is equipment’s worst enemy?
- Dirt and moisture
- Poor maintenance or none at all.
What is the major disadvantages of the manual solution
feed method using sodium fluoride?
- It is not as accurate as other methods.
- The dust generated when adde to the day tank.
- Chemical needs to be manually weighed and added to
a mixing tank.
Downflow fluoride saturator tanks with a gravel bed should
be cleaned at least ________ depending on how fast
hardness scale builds up.
1 to 3 times per year
What type of energy is produced when water moves
through a pipe?
Kinetic energy
Most pressure-sensing devices used in water treatment
plants rely on _______.
The metal-distortion principle
