OIT: Exam
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 used to measure flow in an open channel? - ✔️✔️Weirs or flumes. Flow is
determined by the height of water at a particular point
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 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
What are the 2 types of sampling? - ✔️✔️Grab samples and composite samples
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 are colloids? - ✔️✔️Very small particles suspended in water which are resistant
to settling.
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 turbidity measurement that is visible to the naked eye? - ✔️✔️5 NTU
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 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 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 are screw, gear, piston, diaphragm, and progressive cavity examples of? -
✔️✔️Positive displacement pumps
What are packing glands? - ✔️✔️Seals which prevent the pumped fluid from leaking
from a pump and prevent air from entering
What is the name of the seals which prevent the pumped fluid from leaking from a pump
and prevent air from entering - ✔️✔️Packing glands
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 used to measure flow in an open channel? - ✔️✔️Weirs or flumes. Flow is
determined by the height of water at a particular point
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 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
What are the 2 types of sampling? - ✔️✔️Grab samples and composite samples
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 are colloids? - ✔️✔️Very small particles suspended in water which are resistant
to settling.
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 turbidity measurement that is visible to the naked eye? - ✔️✔️5 NTU
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 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 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 are screw, gear, piston, diaphragm, and progressive cavity examples of? -
✔️✔️Positive displacement pumps
What are packing glands? - ✔️✔️Seals which prevent the pumped fluid from leaking
from a pump and prevent air from entering
What is the name of the seals which prevent the pumped fluid from leaking from a pump
and prevent air from entering - ✔️✔️Packing glands
