Wastewater Operator Class 3 Definitions| 301
questions| with complete solutions
Clean Water Act Correct Answer: 1977 primary legislation concerning water pollution and its
regulation. It establishes the NPDES permit system that prohibits point sources from discharging
pollutants into waters of the United States.
EPA Correct Answer: Environmental Protection Agency is an agency of the federal government
of the United States charged with protecting human health and the environment by writing and
enforcing regulations based on laws passed by Congress
NPDES Correct Answer: National Pollutant Discharge Elimination System is a permit issued by
state or federal government regulating amount of pollutants wastewater treatment plants can
discharge
CFR Correct Answer: Code of Federal Regulations is the codification of the general and
permanent rules and regulations published in the 'Federal Register' by the executive departments
and agencies (like EPA) of the Federal Government of the United States
Wastewater Correct Answer: The spent water of a community from homes, businesses, and
industries
Domestic Wastewater Correct Answer: Wastewater from homes and businesses with little to no
industrial components
Wastewater Physical Characteristics Correct Answer: temperature, color (gray), odor (musty),
turbidity
Sewer Use Ordinance Correct Answer: Local ordinance that addresses what is prohibited from
being discharged and sets limits for particular pollutants
POTW Correct Answer: Publicly Owned Treatment Works. A treatment works, as defined by
Section 212 of the CWA, that is owned by the state or municipality. Includes the treatment plant
and the collection system.
Industrial Pretreatment Program Correct Answer: A program run by a permitting authority
requiring industries to pretreat wastes and establishing discharge limits for the water sent to the
POTW
Sanitary Sewer Correct Answer: Sewer system that transports spent water from homes, business,
and industries to the wastewater treatment plant
SSO Correct Answer: Sanitary Sewer Overflow. Untreated of partiality treated sewage
overflows from a sanitary sewer collection system
,Storm Sewer Correct Answer: Sewer system that transports stormwater runoff to a water body
Combined Sewer System Correct Answer: A sewer system that transports both sanitary sewage
and stormwater typically found in older municipalities
CSO Correct Answer: Combined Sewer Overflow. A discharge of untreated wastewater from a
combined sewer system at a point prior to the headworks of a POTW. CSOs generally occur
during wet weather (rainfall or snowmelt)
Sewer Main Correct Answer: Pipe that collects the wastewater from the system laterals and
branch sewers and conveys it to larger trunk sewers
Trunk Sewers Correct Answer: The main arteries of a collections system that convey water to
treatment plants or interceptors
Manhole Correct Answer: Opening to a sewer line for the purpose of permitting operators or
equipment to enter or leave a sewer
Lift Station Correct Answer: A wastewater pumping station that lifts the wastewater to a higher
elevation; usually the next gravity sewer or the treatment plant
The Collection System Correct Answer: A network of pipes equipment, and appurtenances that
collect, pump, and transport wastewater to the wastewater treatment plant
Slope Correct Answer: The ratio of the vertical distance over the horizontal distance. Rise over
run
Velocity Correct 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 Correct 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 Correct Answer: Devices used to stop or modify the flow of water in a pipe
Check Valve Correct Answer: A valve that normally allows water to flow through it in only one
direction
Inflow Correct Answer: A direct discharge into the sewer system through illegal connections or
surface water entering through faulty joints or displaced manhole covers
Infiltration Correct Answer: The seepage of groundwater into the sewer system through cracked
joints or pipes
Exfiltration Correct Answer: Sewage that unintentionally leaks out of a sewer pipe and into the
environment. Usually from broken pipes, joints, cracks
, Cross-Connection Correct Answer: A connection between a potable water supply and non-
potable water
Backflow Correct Answer: Non-potable water that flows into the potable water supply due to
back pressure
Backsiphonage Correct Answer: Water flowing into the potable water supply due to negative
pressure
FOG Correct Answer: Fats, Oil, and Grease. Congeal in system and cause blockages
Hydrogen Sulfide Correct Answer: Sewer gas that smells like rotten eggs and:
is heavier than air
is explosive when mixed with air
is corrosive
Methane Correct Answer: Sewer gas that is
Colorless
Odorless
Extremely flammable
Forms explosive mixture with air
Displaces oxygen
Septic Condition Correct 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 Correct Answer: An open channel flow meter common in wastewater plants that
has a narrow throat
V-Notch Weirs Correct 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 Correct Answer: The distance around an object, expressed in linear inches, feet, yards,
etc.
Area Correct Answer: The amount of space enclosed by a boundary usually expressed in square
inches, square feet, etc.
Volume Correct Answer: The amount of space enclosed by a three-dimensional object
expressed in cubic inches, cubic feet, cubic yards, etc
questions| with complete solutions
Clean Water Act Correct Answer: 1977 primary legislation concerning water pollution and its
regulation. It establishes the NPDES permit system that prohibits point sources from discharging
pollutants into waters of the United States.
EPA Correct Answer: Environmental Protection Agency is an agency of the federal government
of the United States charged with protecting human health and the environment by writing and
enforcing regulations based on laws passed by Congress
NPDES Correct Answer: National Pollutant Discharge Elimination System is a permit issued by
state or federal government regulating amount of pollutants wastewater treatment plants can
discharge
CFR Correct Answer: Code of Federal Regulations is the codification of the general and
permanent rules and regulations published in the 'Federal Register' by the executive departments
and agencies (like EPA) of the Federal Government of the United States
Wastewater Correct Answer: The spent water of a community from homes, businesses, and
industries
Domestic Wastewater Correct Answer: Wastewater from homes and businesses with little to no
industrial components
Wastewater Physical Characteristics Correct Answer: temperature, color (gray), odor (musty),
turbidity
Sewer Use Ordinance Correct Answer: Local ordinance that addresses what is prohibited from
being discharged and sets limits for particular pollutants
POTW Correct Answer: Publicly Owned Treatment Works. A treatment works, as defined by
Section 212 of the CWA, that is owned by the state or municipality. Includes the treatment plant
and the collection system.
Industrial Pretreatment Program Correct Answer: A program run by a permitting authority
requiring industries to pretreat wastes and establishing discharge limits for the water sent to the
POTW
Sanitary Sewer Correct Answer: Sewer system that transports spent water from homes, business,
and industries to the wastewater treatment plant
SSO Correct Answer: Sanitary Sewer Overflow. Untreated of partiality treated sewage
overflows from a sanitary sewer collection system
,Storm Sewer Correct Answer: Sewer system that transports stormwater runoff to a water body
Combined Sewer System Correct Answer: A sewer system that transports both sanitary sewage
and stormwater typically found in older municipalities
CSO Correct Answer: Combined Sewer Overflow. A discharge of untreated wastewater from a
combined sewer system at a point prior to the headworks of a POTW. CSOs generally occur
during wet weather (rainfall or snowmelt)
Sewer Main Correct Answer: Pipe that collects the wastewater from the system laterals and
branch sewers and conveys it to larger trunk sewers
Trunk Sewers Correct Answer: The main arteries of a collections system that convey water to
treatment plants or interceptors
Manhole Correct Answer: Opening to a sewer line for the purpose of permitting operators or
equipment to enter or leave a sewer
Lift Station Correct Answer: A wastewater pumping station that lifts the wastewater to a higher
elevation; usually the next gravity sewer or the treatment plant
The Collection System Correct Answer: A network of pipes equipment, and appurtenances that
collect, pump, and transport wastewater to the wastewater treatment plant
Slope Correct Answer: The ratio of the vertical distance over the horizontal distance. Rise over
run
Velocity Correct 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 Correct 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 Correct Answer: Devices used to stop or modify the flow of water in a pipe
Check Valve Correct Answer: A valve that normally allows water to flow through it in only one
direction
Inflow Correct Answer: A direct discharge into the sewer system through illegal connections or
surface water entering through faulty joints or displaced manhole covers
Infiltration Correct Answer: The seepage of groundwater into the sewer system through cracked
joints or pipes
Exfiltration Correct Answer: Sewage that unintentionally leaks out of a sewer pipe and into the
environment. Usually from broken pipes, joints, cracks
, Cross-Connection Correct Answer: A connection between a potable water supply and non-
potable water
Backflow Correct Answer: Non-potable water that flows into the potable water supply due to
back pressure
Backsiphonage Correct Answer: Water flowing into the potable water supply due to negative
pressure
FOG Correct Answer: Fats, Oil, and Grease. Congeal in system and cause blockages
Hydrogen Sulfide Correct Answer: Sewer gas that smells like rotten eggs and:
is heavier than air
is explosive when mixed with air
is corrosive
Methane Correct Answer: Sewer gas that is
Colorless
Odorless
Extremely flammable
Forms explosive mixture with air
Displaces oxygen
Septic Condition Correct 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 Correct Answer: An open channel flow meter common in wastewater plants that
has a narrow throat
V-Notch Weirs Correct 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 Correct Answer: The distance around an object, expressed in linear inches, feet, yards,
etc.
Area Correct Answer: The amount of space enclosed by a boundary usually expressed in square
inches, square feet, etc.
Volume Correct Answer: The amount of space enclosed by a three-dimensional object
expressed in cubic inches, cubic feet, cubic yards, etc
