OIT Exam with 100% correct answers
updated 2024
What are colloids? - ANSWER- Very small particles suspended in water which are
resistant to settling.
What is turbidity measured in? - ANSWER- Nephelometric Turbidity Units (NTU)
What is the turbidity measurement that is visible to the naked eye? - ANSWER- 5
NTU
What is an important indicator of treatment efficiency and particularly the
efficiency of filters and disinfection processes? - ANSWER- Turbidity
Why are particles that cause turbidity harmful? - ANSWER- 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? - ANSWER- Grab samples and composite
samples
What are grab samples and when is it used? - ANSWER- 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? - ANSWER- 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? - ANSWER- Electrical potential or potential difference between
two points. Indicated the strength of the "push" on current
What is current and what are its units? - ANSWER- Flow off electric charge.
Measured in amperes
What is the typical rate of change (Hz) or alternating current? - ANSWER- 60
cycles per second
What happens when wires or appliances carry more than their rated capacity of
current? - ANSWER- May overheat and cause fires. Circuit breakers stop this
What is the equation for voltage? - ANSWER- V=IR
What is Power (P), what is is measured in and what is the formula? - ANSWER-
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? - ANSWER- Flow (Q)
Q= AV
What can flow provide info on? - ANSWER- Dentention time in tanks, flow
between various processes or sections, chemical feed rates, etc.
What are the types of flow measurement determined by? - ANSWER- Whether
water is flowing in a closed pipe of an open channel
What is used to measure flow in an open channel? - ANSWER- Weirs or flumes.
Flow is determined by the height of water at a particular point
What is a flume? - ANSWER- A specially shaped constriction in the channel
What is a weir? - ANSWER- A dam or obstruction in the channel
What are venturi meters, ultrasonic meters, magnetic meters, doppler meters and
orifice meters used for? - ANSWER- Measuring flow in closed pipes.
, What is static pressure? - ANSWER- The force exerted when water is at rest and
not flowing
What is the pressure exerted by flowing water known as? - ANSWER- Dynamic
pressure
What is the force exerted when water is at rest and not flowing? - ANSWER- Static
pressure
What is the rise of water in a tube known as? - ANSWER- The head
What is the pressure loss due to friction as water flows through a pipe/filter etc? -
ANSWER- Headloss
What is headloss? - ANSWER- the pressure loss due to friction as water flows
through a pipe/filter etc
What can decrease head loss? - ANSWER- Larger diameter and smoother interior
surface
How can you make up for head loss? - ANSWER- Energy inputs (pumping)
When does water hammer occur? - ANSWER- When a moving fluid suddenly
stops, can destroy piping and appurtenances
How can you avoid water hammer? - ANSWER- Operate valves slowly and start
and stop valves gradually
What is cavitation and how does it occur? - ANSWER- 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? - ANSWER- A vibration noise
similar to hammering of the pump impeller
updated 2024
What are colloids? - ANSWER- Very small particles suspended in water which are
resistant to settling.
What is turbidity measured in? - ANSWER- Nephelometric Turbidity Units (NTU)
What is the turbidity measurement that is visible to the naked eye? - ANSWER- 5
NTU
What is an important indicator of treatment efficiency and particularly the
efficiency of filters and disinfection processes? - ANSWER- Turbidity
Why are particles that cause turbidity harmful? - ANSWER- 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? - ANSWER- Grab samples and composite
samples
What are grab samples and when is it used? - ANSWER- 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? - ANSWER- 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? - ANSWER- Electrical potential or potential difference between
two points. Indicated the strength of the "push" on current
What is current and what are its units? - ANSWER- Flow off electric charge.
Measured in amperes
What is the typical rate of change (Hz) or alternating current? - ANSWER- 60
cycles per second
What happens when wires or appliances carry more than their rated capacity of
current? - ANSWER- May overheat and cause fires. Circuit breakers stop this
What is the equation for voltage? - ANSWER- V=IR
What is Power (P), what is is measured in and what is the formula? - ANSWER-
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? - ANSWER- Flow (Q)
Q= AV
What can flow provide info on? - ANSWER- Dentention time in tanks, flow
between various processes or sections, chemical feed rates, etc.
What are the types of flow measurement determined by? - ANSWER- Whether
water is flowing in a closed pipe of an open channel
What is used to measure flow in an open channel? - ANSWER- Weirs or flumes.
Flow is determined by the height of water at a particular point
What is a flume? - ANSWER- A specially shaped constriction in the channel
What is a weir? - ANSWER- A dam or obstruction in the channel
What are venturi meters, ultrasonic meters, magnetic meters, doppler meters and
orifice meters used for? - ANSWER- Measuring flow in closed pipes.
, What is static pressure? - ANSWER- The force exerted when water is at rest and
not flowing
What is the pressure exerted by flowing water known as? - ANSWER- Dynamic
pressure
What is the force exerted when water is at rest and not flowing? - ANSWER- Static
pressure
What is the rise of water in a tube known as? - ANSWER- The head
What is the pressure loss due to friction as water flows through a pipe/filter etc? -
ANSWER- Headloss
What is headloss? - ANSWER- the pressure loss due to friction as water flows
through a pipe/filter etc
What can decrease head loss? - ANSWER- Larger diameter and smoother interior
surface
How can you make up for head loss? - ANSWER- Energy inputs (pumping)
When does water hammer occur? - ANSWER- When a moving fluid suddenly
stops, can destroy piping and appurtenances
How can you avoid water hammer? - ANSWER- Operate valves slowly and start
and stop valves gradually
What is cavitation and how does it occur? - ANSWER- 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? - ANSWER- A vibration noise
similar to hammering of the pump impeller
