WASTEWATER OPERATOR CLASS C FINAL
STUDY PAPER 2026 COMPLETE QUESTIONS
AND ANSWERS
◉ Slope. Answer: The ratio of the vertical distance over the
horizontal distance. Rise over run
◉ Velocity. Answer: Ratio of distance over time (miles per hour)
Minimum 2 ft/sec prevents solids from dropping out. Maximum 10
ft/sec because more than that causes scouring
◉ Roughness Coefficient. Answer: Related to the roughness of the
interior of a pipe. Manning's formula. Roughness coefficient "n" The
higher the value, the rougher the pipe
◉ Valves. Answer: Devices used to stop or modify the flow of water
in a pipe
◉ Check Valve. Answer: A valve that normally allows water to flow
through it in only one direction
,◉ Inflow. Answer: A direct discharge into the sewer system through
illegal connections or surface water entering through faulty joints or
displaced manhole covers
◉ Infiltration. Answer: The seepage of groundwater into the sewer
system through cracked joints or pipes
◉ Exfiltration. Answer: Sewage that unintentionally leaks out of a
sewer pipe and into the environment. Usually from broken pipes,
joints, cracks
◉ Cross-Connection. Answer: A connection between a potable water
supply and non-potable water
◉ Backflow. Answer: Non-potable water that flows into the potable
water supply due to back pressure
◉ Backsiphonage. Answer: Water flowing into the potable water
supply due to negative pressure
◉ FOG. Answer: Fats, Oil, and Grease. Congeal in system and cause
blockages
,◉ Hydrogen Sulfide. Answer: Sewer gas that smells like rotten eggs
and:
is heavier than air
is explosive when mixed with air
is corrosive
◉ Methane. Answer: Sewer gas that is
Colorless
Odorless
Extremely flammable
Forms explosive mixture with air
Displaces oxygen
◉ Septic Condition. Answer: A condition in sewers resulting from
gases produced by anaerobic bacteria when sewage sits for too long
Characteristics
Foul odor
Black appearance
Little or no D.O.
High oxygen demand
, ◉ Parshall Flume. Answer: An open channel flow meter common in
wastewater plants that has a narrow throat
◉ V-Notch Weirs. Answer: An open channel flow meter used in
wastewater plants to measure small flows that is a "V" shape cut out
of a weir
◉ Perimeter. Answer: The distance around an object, expressed in
linear inches, feet, yards, etc.
◉ Area. Answer: The amount of space enclosed by a boundary
usually expressed in square inches, square feet, etc.
◉ Volume. Answer: The amount of space enclosed by a three-
dimensional object expressed in cubic inches, cubic feet, cubic yards,
etc
◉ Flow. Answer: Volume per unit of time
◉ Velocity (definition). Answer: the distance traveled per unit of
time
◉ Preliminary Treatment. Answer: Prepares wastewater for
downstream plant processes. The main preliminary process are:
STUDY PAPER 2026 COMPLETE QUESTIONS
AND ANSWERS
◉ Slope. Answer: The ratio of the vertical distance over the
horizontal distance. Rise over run
◉ Velocity. Answer: Ratio of distance over time (miles per hour)
Minimum 2 ft/sec prevents solids from dropping out. Maximum 10
ft/sec because more than that causes scouring
◉ Roughness Coefficient. Answer: Related to the roughness of the
interior of a pipe. Manning's formula. Roughness coefficient "n" The
higher the value, the rougher the pipe
◉ Valves. Answer: Devices used to stop or modify the flow of water
in a pipe
◉ Check Valve. Answer: A valve that normally allows water to flow
through it in only one direction
,◉ Inflow. Answer: A direct discharge into the sewer system through
illegal connections or surface water entering through faulty joints or
displaced manhole covers
◉ Infiltration. Answer: The seepage of groundwater into the sewer
system through cracked joints or pipes
◉ Exfiltration. Answer: Sewage that unintentionally leaks out of a
sewer pipe and into the environment. Usually from broken pipes,
joints, cracks
◉ Cross-Connection. Answer: A connection between a potable water
supply and non-potable water
◉ Backflow. Answer: Non-potable water that flows into the potable
water supply due to back pressure
◉ Backsiphonage. Answer: Water flowing into the potable water
supply due to negative pressure
◉ FOG. Answer: Fats, Oil, and Grease. Congeal in system and cause
blockages
,◉ Hydrogen Sulfide. Answer: Sewer gas that smells like rotten eggs
and:
is heavier than air
is explosive when mixed with air
is corrosive
◉ Methane. Answer: Sewer gas that is
Colorless
Odorless
Extremely flammable
Forms explosive mixture with air
Displaces oxygen
◉ Septic Condition. Answer: A condition in sewers resulting from
gases produced by anaerobic bacteria when sewage sits for too long
Characteristics
Foul odor
Black appearance
Little or no D.O.
High oxygen demand
, ◉ Parshall Flume. Answer: An open channel flow meter common in
wastewater plants that has a narrow throat
◉ V-Notch Weirs. Answer: An open channel flow meter used in
wastewater plants to measure small flows that is a "V" shape cut out
of a weir
◉ Perimeter. Answer: The distance around an object, expressed in
linear inches, feet, yards, etc.
◉ Area. Answer: The amount of space enclosed by a boundary
usually expressed in square inches, square feet, etc.
◉ Volume. Answer: The amount of space enclosed by a three-
dimensional object expressed in cubic inches, cubic feet, cubic yards,
etc
◉ Flow. Answer: Volume per unit of time
◉ Velocity (definition). Answer: the distance traveled per unit of
time
◉ Preliminary Treatment. Answer: Prepares wastewater for
downstream plant processes. The main preliminary process are:
