OIT Exam
What is the turbidity measurement that is visible to the naked eye? - ✔️✔️5 NTU
What is the purpose of flocculation? - ✔️✔️To achieve optimum size particles which
will readily settle out of the water or can be easily filtered. Addition of too much or too
little coagulant decreases the efficiency of the treatment process.
What are packing glands? - ✔️✔️Seals which prevent the pumped fluid from leaking
from a pump and prevent air from entering
What is backflow siphonage caused by in distribution systems? - ✔️✔️Unprotected
connection to any equipment or device having a pressure higher than that in the water
main. Can be due to a drop in pressure due to a waterman break
What is turbidity measured in? - ✔️✔️Nephelometric Turbidity Units (NTU)
What is an important indicator of treatment efficiency and particularly the efficiency of
filters and disinfection processes? - ✔️✔️Turbidity
Why are particles that cause turbidity harmful? - ✔️✔️They can hide or entrap harmful
organisms so that the disinfectant is unable to reach them. It calls increases CL demand
which can be carcinogenic
What are the 2 types of sampling? - ✔️✔️Grab samples and composite samples
What are grab samples and when is it used? - ✔️✔️A single sample taken at one place
and time. Used when water quality and quantity are not variable
What is a composite sample and when is it used? - ✔️✔️A series of samples taken
over a period of time which are combined to form a single sample. Necessary if water
quality changes greatly over time.
What is voltage? - ✔️✔️Electrical potential or potential difference between two points.
Indicated the strength of the "push" on current
What is current and what are its units? - ✔️✔️Flow off electric charge. Measured in
amperes
,What is the typical rate of change (Hz) or alternating current? - ✔️✔️60 cycles per
second
What happens when wires or appliances carry more than their rated capacity of
current? - ✔️✔️May overheat and cause fires. Circuit breakers stop this
What is the equation for voltage? - ✔️✔️V=IR
What is Power (P), what is is measured in and what is the formula? - ✔️✔️The rate at
which work is done or energy is produced.
Measured in Watts
P=VI
What is the symbol for flow and what is the formula for it? - ✔️✔️Flow (Q)
Q= AV
What can flow provide info on? - ✔️✔️Dentention time in tanks, flow between various
processes or sections, chemical feed rates, etc.
What are the types of flow measurement determined by? - ✔️✔️Whether water is
flowing in a closed pipe of an open channel
What is used to measure flow in an open channel? - ✔️✔️Weirs or flumes. Flow is
determined by the height of water at a particular point
What is a flume? - ✔️✔️A specially shaped constriction in the channel
What is a weir? - ✔️✔️A dam or obstruction in the channel
What are venturi meters, ultrasonic meters, magnetic meters, doppler meters and orifice
meters used for? - ✔️✔️Measuring flow in closed pipes.
What is static pressure? - ✔️✔️The force exerted when water is at rest and not flowing
What is the pressure exerted by flowing water known as? - ✔️✔️Dynamic pressure
What is the force exerted when water is at rest and not flowing? - ✔️✔️Static pressure
What is the rise of water in a tube known as? - ✔️✔️The head
What is the pressure loss due to friction as water flows through a pipe/filter etc? -
✔️✔️Headloss
, What is headloss? - ✔️✔️the pressure loss due to friction as water flows through a
pipe/filter etc
What can decrease head loss? - ✔️✔️Larger diameter and smoother interior surface
How can you make up for head loss? - ✔️✔️Energy inputs (pumping)
When does water hammer occur? - ✔️✔️When a moving fluid suddenly stops, can
destroy piping and appurtenances
How can you avoid water hammer? - ✔️✔️Operate valves slowly and start and stop
valves gradually
What is cavitation and how does it occur? - ✔️✔️The formation and collapse of a
bobble or gas pocket. Can result from very low pressure within pump which causes
water to boil, releasing tiny bubbles. The bubbles then collapse with enough force to
damage the pump impeller
What are indications that cavitation is occurring? - ✔️✔️A vibration noise similar to
hammering of the pump impeller
What are the 2 basic types of pumps? - ✔️✔️Centrifugal and displacement
What is a centrifugal pump? - ✔️✔️Pressurizes water by "throwing it" at high speeds
from the centre of the impeller to the outside.
What is an impeller and what does it do? - ✔️✔️A rotating disk with a set of vanes
coupled to the engine/motor shaft that produces centrifugal force within the pump
casing.
What is a volute? - ✔️✔️A specially designed chamber that widens within the pump
that liquid accelerates out of
What is the name of the chamber of a centrifugal pump? - ✔️✔️Volute
What is the name of the spinner in a centrifugal pump? - ✔️✔️Impeller
How are centrifugal pumps classified? - ✔️✔️By their shapes
What are radial vane, Francis vane, mixed flow and axial flow examples of? -
✔️✔️Centrifugal pumps
How do positive displacement pumps work? - ✔️✔️Push fluid mechanically. Starts with
a suction valve and discharge valve open
What is the turbidity measurement that is visible to the naked eye? - ✔️✔️5 NTU
What is the purpose of flocculation? - ✔️✔️To achieve optimum size particles which
will readily settle out of the water or can be easily filtered. Addition of too much or too
little coagulant decreases the efficiency of the treatment process.
What are packing glands? - ✔️✔️Seals which prevent the pumped fluid from leaking
from a pump and prevent air from entering
What is backflow siphonage caused by in distribution systems? - ✔️✔️Unprotected
connection to any equipment or device having a pressure higher than that in the water
main. Can be due to a drop in pressure due to a waterman break
What is turbidity measured in? - ✔️✔️Nephelometric Turbidity Units (NTU)
What is an important indicator of treatment efficiency and particularly the efficiency of
filters and disinfection processes? - ✔️✔️Turbidity
Why are particles that cause turbidity harmful? - ✔️✔️They can hide or entrap harmful
organisms so that the disinfectant is unable to reach them. It calls increases CL demand
which can be carcinogenic
What are the 2 types of sampling? - ✔️✔️Grab samples and composite samples
What are grab samples and when is it used? - ✔️✔️A single sample taken at one place
and time. Used when water quality and quantity are not variable
What is a composite sample and when is it used? - ✔️✔️A series of samples taken
over a period of time which are combined to form a single sample. Necessary if water
quality changes greatly over time.
What is voltage? - ✔️✔️Electrical potential or potential difference between two points.
Indicated the strength of the "push" on current
What is current and what are its units? - ✔️✔️Flow off electric charge. Measured in
amperes
,What is the typical rate of change (Hz) or alternating current? - ✔️✔️60 cycles per
second
What happens when wires or appliances carry more than their rated capacity of
current? - ✔️✔️May overheat and cause fires. Circuit breakers stop this
What is the equation for voltage? - ✔️✔️V=IR
What is Power (P), what is is measured in and what is the formula? - ✔️✔️The rate at
which work is done or energy is produced.
Measured in Watts
P=VI
What is the symbol for flow and what is the formula for it? - ✔️✔️Flow (Q)
Q= AV
What can flow provide info on? - ✔️✔️Dentention time in tanks, flow between various
processes or sections, chemical feed rates, etc.
What are the types of flow measurement determined by? - ✔️✔️Whether water is
flowing in a closed pipe of an open channel
What is used to measure flow in an open channel? - ✔️✔️Weirs or flumes. Flow is
determined by the height of water at a particular point
What is a flume? - ✔️✔️A specially shaped constriction in the channel
What is a weir? - ✔️✔️A dam or obstruction in the channel
What are venturi meters, ultrasonic meters, magnetic meters, doppler meters and orifice
meters used for? - ✔️✔️Measuring flow in closed pipes.
What is static pressure? - ✔️✔️The force exerted when water is at rest and not flowing
What is the pressure exerted by flowing water known as? - ✔️✔️Dynamic pressure
What is the force exerted when water is at rest and not flowing? - ✔️✔️Static pressure
What is the rise of water in a tube known as? - ✔️✔️The head
What is the pressure loss due to friction as water flows through a pipe/filter etc? -
✔️✔️Headloss
, What is headloss? - ✔️✔️the pressure loss due to friction as water flows through a
pipe/filter etc
What can decrease head loss? - ✔️✔️Larger diameter and smoother interior surface
How can you make up for head loss? - ✔️✔️Energy inputs (pumping)
When does water hammer occur? - ✔️✔️When a moving fluid suddenly stops, can
destroy piping and appurtenances
How can you avoid water hammer? - ✔️✔️Operate valves slowly and start and stop
valves gradually
What is cavitation and how does it occur? - ✔️✔️The formation and collapse of a
bobble or gas pocket. Can result from very low pressure within pump which causes
water to boil, releasing tiny bubbles. The bubbles then collapse with enough force to
damage the pump impeller
What are indications that cavitation is occurring? - ✔️✔️A vibration noise similar to
hammering of the pump impeller
What are the 2 basic types of pumps? - ✔️✔️Centrifugal and displacement
What is a centrifugal pump? - ✔️✔️Pressurizes water by "throwing it" at high speeds
from the centre of the impeller to the outside.
What is an impeller and what does it do? - ✔️✔️A rotating disk with a set of vanes
coupled to the engine/motor shaft that produces centrifugal force within the pump
casing.
What is a volute? - ✔️✔️A specially designed chamber that widens within the pump
that liquid accelerates out of
What is the name of the chamber of a centrifugal pump? - ✔️✔️Volute
What is the name of the spinner in a centrifugal pump? - ✔️✔️Impeller
How are centrifugal pumps classified? - ✔️✔️By their shapes
What are radial vane, Francis vane, mixed flow and axial flow examples of? -
✔️✔️Centrifugal pumps
How do positive displacement pumps work? - ✔️✔️Push fluid mechanically. Starts with
a suction valve and discharge valve open
