Types of Wastewater Collection Systems: Gravity Sewers, Force Mains, and Combined Sewers

Question 1

Which type of wastewater collection system is most commonly used in residential areas?

Accepted Answer

Gravity sewers

Answer

Force mains

Answer

Combined sewers

Question 2

What is a key advantage of utilizing a force main in a wastewater collection system?

Accepted Answer

Force mains enable wastewater transportation over extended distances and uphill.

Answer

Force mains are more economical to install and maintain compared to gravity sewers.

Answer

Force mains offer greater environmental sustainability than gravity sewers.

Question 3

Which wastewater collection system relies solely on gravity to transport wastewater?

Accepted Answer

Gravity sewers

Answer

Force mains

Answer

Combined sewers

Question 4

What is the main advantage of utilizing force mains in wastewater collection systems?

Accepted Answer

They can transport wastewater over challenging terrains and long distances.

Answer

They need less maintenance compared to gravity sewers.

Answer

They are more cost-effective than other wastewater collection systems.

Question 5

Which wastewater collection system combines flows from domestic and industrial sources into a single pipe?

Accepted Answer

Combined sewers

Answer

Gravity sewers

Answer

Force mains

Question 6

What is a potential environmental concern with combined sewers?

Accepted Answer

Discharge of untreated wastewater into waterways.

Answer

Increased risk of flooding during heavy rainfall events.

Answer

Corrosion of infrastructure due to combined flows.

Question 7

What is a significant advantage of utilizing force mains in wastewater collection?

Accepted Answer

Increased flow capacity

Answer

Lower construction costs

Answer

Reduced maintenance requirements

Question 8

What is the primary function of a wet well in a force main system?

Accepted Answer

Temporary storage of wastewater prior to pumping

Answer

Reduction of excessive pressure within the force main

Answer

Provision of access for maintenance purposes

Question 9

Which type of pipe joint is typically used for vitrified clay gravity sewers?

Accepted Answer

Bell and spigot joint

Answer

Threaded joint

Answer

Solvent-welded joint

Question 10

What is the primary purpose of a manhole in a wastewater collection system?

Accepted Answer

Access point for maintenance, inspection, and cleaning

Answer

Flow control and regulation structure

Answer

Temporary storage tank for wastewater overflow

Question 11

In determining the optimal location for a pumping station in a wastewater collection system, which factor is paramount?

Accepted Answer

Elevation of the collection area

Answer

Availability of electricity

Answer

Proximity to treatment facilities

Answer

Presence of natural water bodies

Question 12

In wastewater collection systems, which type utilizes pumps to transport wastewater from lower elevations to higher ones?

Accepted Answer

Force mains

Answer

Gravity sewers

Answer

Combined sewers

Question 13

Which wastewater collection system employs pumps for transportation?

Accepted Answer

Force mains

Answer

Gravity sewers

Answer

Combined sewers

Answer

Septic tanks

Question 14

What is the primary purpose of a check valve in a wastewater collection system?

Accepted Answer

Prevention of wastewater backflow

Answer

Regulation of wastewater flow

Answer

Maintenance access provision

Answer

Removal of solids from wastewater

Question 15

Which type of wastewater collection system utilizes gravity to convey wastewater through pipes?

Accepted Answer

Gravity sewers

Answer

Force mains

Answer

Pumped sewers

Answer

Vacuum sewers

Question 16

What is the main drawback associated with the utilization of force mains in wastewater collection systems?

Accepted Answer

High energy consumption

Answer

Prone to clogging

Answer

Limited flow capacity

Answer

Difficult to maintain

Question 17

Which type of wastewater collection system conveys both sanitary sewage and stormwater runoff in a single pipe?

Accepted Answer

Combined sewers

Answer

Force mains

Answer

Gravity sewers

Question 18

What is the primary purpose of an interceptor in a wastewater collection system?

Accepted Answer

To prevent untreated wastewater from overflowing into natural water bodies during heavy rainfall events

Answer

To disinfect wastewater before discharge

Answer

To reduce the flow rate of wastewater

Answer

To separate sanitary and stormwater flow

Question 19

Which maintenance technique involves using a high-pressure water jet to remove debris and blockages from sewer pipes?

Accepted Answer

Hydro jetting

Answer

Mechanical cleaning

Answer

Pneumatic cleaning

Answer

Chemical cleaning

Question 20

What is the purpose of a manhole in a wastewater collection system?

Accepted Answer

To provide access for inspection, maintenance, and cleaning of sewer pipes

Answer

To regulate the flow of wastewater

Answer

To disinfect wastewater

Answer

To remove solids from wastewater

Question 21

Which type of wastewater collection system is most appropriate for areas with relatively flat terrain and low elevation changes?

Accepted Answer

Gravity sewers

Answer

Vacuum sewers

Answer

Combined sewers

Answer

Force mains

Question 22

What is a potential environmental concern associated with combined sewer overflows (CSOs) during heavy rainfall events?

Accepted Answer

Water pollution due to the discharge of untreated wastewater into natural water bodies

Answer

Air pollution

Answer

Soil contamination

Answer

Noise pollution