appurtenances in sewerage system are as four type

sewage appurtenances

The different devices required for construction, operation and maintenance of the entire sewerage system is known as sewerage appurtenances. These are classified as follows :

1. Manhole section

2. Catch basin section

3. Flushing tank parts

4. Ventilation shaft

1. manhole section : manhole chamber is an opening in a sewer line to provide access for a man for the purpose of inspection and cleaning of sewers. The manholes are generally located at all changes of direction, at all changes of gradients and at all junctions of main and branch sewers. The maximum distance between manhole, for large sewers, should be 300 meters. The essential parts of a manhole are a working chamber, an access shaft, cover and steps of iron. The lower portion of a manhole is called a working chamber. The minimum diameter of a manhole cover should be 50 cm.

manhole chamber

2. Catch basin section : Catch basin is a structure constructed in the form of a chamber and provided along the sewer line to admit clear rain water free from suspended silt and grit, floating rubbish etc. into the combined sewer. The catch basin in sewer are located when the sewers are laid at very small gradient and the velocity of flow of sewage is less than the self cleaning velocity. With the help of the catch basin, the water that enters the sewer helps in cleaning the sewer.

catch basin section in sewer

3. flushing tank parts : a flushing tank are used to hold and throw water into the sewer for the purpose of cleaning. These are usually provided at the beginning of the sewers and may be either hand operated or automatic.

4. ventilation shaft : ventilation shaft design is a shaft provided for the purpose of ventilation of sewers. The ventilation shafts are required to prevent the accumulation of dangerous explosive and corrosive gases.

ventilation shaft in sewer