Suitable Section of a Sewer in a Combined Sewerage System

In a combined sewerage system, sewage and stormwater are collected in a single pipe network. The design of the sewer system is critical in ensuring efficient and effective removal of wastewater from the community. The most suitable section of the sewer in a combined sewerage system is egg-shaped.

Advantages of Egg-Shaped Sewers

1. Self-Cleaning Capacity: Egg-shaped sewers have a self-cleaning capacity due to the high velocity of flow in the center of the sewer. The velocity of flow decreases towards the sides of the sewer, allowing solids and debris to settle at the bottom and flow out with the wastewater.

2. Efficient Flow: Egg-shaped sewers have a larger hydraulic radius, which means that they can carry more wastewater compared to circular or rectangular sewers of the same cross-sectional area.

3. Reduced Maintenance: Egg-shaped sewers require less maintenance compared to other sewer shapes because of their self-cleaning capacity. This reduces the need for regular cleaning and desilting, which can be time-consuming and expensive.

4. Cost-Effective: Egg-shaped sewers are cost-effective in terms of construction and maintenance. They require less material and are easier to install compared to other sewer shapes.

Conclusion

In conclusion, egg-shaped sewers are the most suitable section of a sewer in a combined sewerage system due to their self-cleaning capacity, efficient flow, reduced maintenance, and cost-effectiveness. The design of the sewer system plays a critical role in ensuring the efficient and effective removal of wastewater from the community.

Circular sewer is effective when the section runs atleast half full when depth goes below half depth, not effective..!
if circular sewer is used for combined it will be effective during maximum rain water flow but during dry weather flow, not effective

that's why circular sewer are assumed egg shape sewer in which smaller portion effective during dry weather and big portion is effective during maximum rain water flow.!!!