Advanced Water Treatment Chapter 3
Exam Questions and Answers
Why should the operator be familiar with the wastewater collection and transportation
network? - Answer-By knowing the origin of wastes reaching the plant, the time it takes,
and how the wastes are transported, the operator will be able to spot troubles and take
corrective action.
What problems may occur when it takes a long time for wastewater to flow through he
collection sewers to the treatment plant? - Answer-Hydrogen sulfide gas may be
released by anaerobic bacteria feeding on the wastes. This can cause odor problems,
damage concrete in the plant, and make the wastes more difficult to treat.
List three types of sewers. - Answer-sanitary, storm, combined
Why are combined sewers a problem? - Answer-Flows sometimes may become
overloaded during storms due to inadequate capacity. This could allow partially treated
wastes to be discharged into receiving waters as a result of attempting to treat extreme
hydraulic overloads.
Why is grit removed early in the treatment process? - Answer-It is abrasive and will
rapidly wear out pumps and other equipment.
What is usually done with grit that has been removed from the wastewater? - Answer-
Buried to avoid nuisance conditions
Why is a Parshall flume widely used for measuring wastewater flow? - Answer-Their
smooth constriction does not offer any protruding sharp edges or areas where
wastewater particles may catch or collect behind the metering device.
What are the disadvantages of using weirs to measure influent flows at the head end of
the plant? - Answer-Organic solids may settle out in this area. When this occurs, odors
and unsightliness can result. As the solids accumulate, the flow may become incorrect.
What is the purpose of flights or plows in a clarifier? - Answer-Flights in rectangular
tanks move scum along the surface to a scum trough and push sludge along the bottom
to a hopper for removal to the sludge handling facility. Plows scrape sludge along the
bottom of circular tanks to a hopper for removal.
What happens to the sludge and scum collected in a primary clarifier? - Answer-Usually
pumped to sludge handling facilities such as digesters.
Would it be a good idea to use trickling filter media of various sizes so it could pack
together better? - Answer-No
Exam Questions and Answers
Why should the operator be familiar with the wastewater collection and transportation
network? - Answer-By knowing the origin of wastes reaching the plant, the time it takes,
and how the wastes are transported, the operator will be able to spot troubles and take
corrective action.
What problems may occur when it takes a long time for wastewater to flow through he
collection sewers to the treatment plant? - Answer-Hydrogen sulfide gas may be
released by anaerobic bacteria feeding on the wastes. This can cause odor problems,
damage concrete in the plant, and make the wastes more difficult to treat.
List three types of sewers. - Answer-sanitary, storm, combined
Why are combined sewers a problem? - Answer-Flows sometimes may become
overloaded during storms due to inadequate capacity. This could allow partially treated
wastes to be discharged into receiving waters as a result of attempting to treat extreme
hydraulic overloads.
Why is grit removed early in the treatment process? - Answer-It is abrasive and will
rapidly wear out pumps and other equipment.
What is usually done with grit that has been removed from the wastewater? - Answer-
Buried to avoid nuisance conditions
Why is a Parshall flume widely used for measuring wastewater flow? - Answer-Their
smooth constriction does not offer any protruding sharp edges or areas where
wastewater particles may catch or collect behind the metering device.
What are the disadvantages of using weirs to measure influent flows at the head end of
the plant? - Answer-Organic solids may settle out in this area. When this occurs, odors
and unsightliness can result. As the solids accumulate, the flow may become incorrect.
What is the purpose of flights or plows in a clarifier? - Answer-Flights in rectangular
tanks move scum along the surface to a scum trough and push sludge along the bottom
to a hopper for removal to the sludge handling facility. Plows scrape sludge along the
bottom of circular tanks to a hopper for removal.
What happens to the sludge and scum collected in a primary clarifier? - Answer-Usually
pumped to sludge handling facilities such as digesters.
Would it be a good idea to use trickling filter media of various sizes so it could pack
together better? - Answer-No
