Collection Systems
Wastewater Collection Systems
Learning Objectives:
- Understand the purpose and significance of wastewater collection systems in maintaining public health and protecting the environment.
- Recognize the role of civil engineers in the design, construction, and operation of these systems.
- Familiarize yourself with the key components of wastewater collection systems, including sanitary sewers, stormwater sewers, manholes, lift stations, and wastewater treatment plants.
- Differentiate between sanitary sewer systems and stormwater sewer systems, understanding their distinct functions and design considerations.
- Learn about combined sewer systems and their challenges in managing both sewage and stormwater.
Sanitary Sewer Systems:
Purpose: Sanitary sewer systems, also known as wastewater or sewage systems, collect and transport domestic, commercial, and industrial wastewater from buildings and residences to wastewater treatment plants.
Contents: These systems carry sewage, which includes human waste, domestic water from sinks and toilets, and industrial wastewater.
Separation from Stormwater: Sanitary sewers are typically separate from stormwater sewers to prevent contamination of natural water bodies.
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Solved Example: 9082-01
In sewerage system drop manholes are provided when there is a:
A. Sloping ground, with drop more than 0.6 m is required to control the gradient.
B. Change in alignment of sewer line
C. Change in size of sewers
D. Change from gravity system to pressure system
Correct Answer: A
Solved Example: 9082-02
The diameter of a domestic sewer pipe laid at gradient 1 in 100 is recommended:
A. 100 mm
B. 150 mm
C. 200 mm
D. 175 mm
Correct Answer: B
Solved Example: 9082-03
Intercepting traps are often provided at the junction of:
A. Sullage pipe and floors of kitchen and bath
B. House sewer and municipal sewer
C. Ventilating column and lateral sewer
D. Room or roof drain and the other drain coming from bath and kitchen
Correct Answer: B
Solved Example: 9082-04
Which of the following sewers collects the discharge from a collecting system and delivers it to a treatment plant?
A. Outfall sewer
B. Branch sewer
C. House sewer
D. Lateral sewer
Correct Answer: A
Solved Example: 9082-05
Sewer lines having difference of more than 600 mm in the water lines and inverse level of two sewers are connected with a:
A. Siphon
B. Manhole
C. Inspection chamber
D. Drop manhole
Correct Answer: D
Solved Example: 9082-06
Two sewer pipelines A and B (having the same diameter and made of the same material) are laid at a bed slope of 1 in 225 and 1 in 625, respectively. Determine the ratio of their carrying capacities (Q$_A$ to Q$_B$).
A. $\dfrac{5}{3}$
B. 1
C. $\dfrac{3}{5}$
D. $\dfrac{2}{5}$
Correct Answer: A
Stormwater Collection Systems
Learning Objectives:
- Understand the significance of stormwater management in civil engineering and its role in preventing urban flooding, erosion, and water pollution.
- Comprehend the principles of stormwater hydrology, including rainfall patterns, runoff generation, and factors influencing the volume and intensity of stormwater runoff.
- Identify and describe the key components of stormwater collection systems, such as catch basins, storm sewers, culverts, detention basins, and retention ponds.
Stormwater Sewer Systems:
Purpose: Stormwater sewer systems, also known as storm drains or storm sewers, manage rainfall and surface runoff, preventing flooding and erosion in urban areas.
Contents: They transport rainwater, which may carry debris, pollutants, and sediments from streets and paved surfaces.
Separation from Sanitary Sewers: Stormwater sewers are separate from sanitary sewers to reduce the volume of wastewater treated at treatment plants.
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Solved Example: 9264-01
Water harvesting is a method which:
A. Increase ground water level
B. Not practised in modern days
C. Has no relation with ground water
D. Decrease ground water level
Correct Answer: A