Sewer appurtenances

Sanitary Engineering

1. Group Members: S harmistha, 151 S hikshita, 152 S hrijan, 153 Shubham, 154 Siddhi, 155 Sital, 156 Tutor: Asst. Prof. Shukra Raj Paudel Department of Civil Engineering IOE, Tribhuvan University 2018 - 7- 30 4.0 SEWER APPURTENANCES

2. 2 Objectives of the Presentation To be familiar with various sewer appurtenances To know about the working of sewer appurtenances

3. 3 Presentation outlines Definition of Sewer Appurtenances Necessity of Sewer Appurtenances Manhole Drop manhole Lamp hole Street inlets Catch basin Flushing device Sand, grease and oil traps Inverted siphon Sewer outlet Ventilating shaft

4. Sewer appurtenances Definition : Sewer appurtenances are the various essential accessories or devices for the proper maintenances & efficient operation of sewerage system. 4

5. 1. Necessity of sewer appurtenances To inspect the sewer. To help in cleaning the sewers. Source: http://www.surrey.ca/city-services/17499.aspx Fig. Inspection of sewer 89 5

6. 1. Manhole Fig. Manhole Source: http://dirtyfluid.blogspot.com/search/label/Sewer%20Appurtenances 89 6

7. 1. Manhole It permits inspection and cleaning as well as repair of sewers, and removal of any obstructions; and, also they allow sampling and flow measurement. Most manholes are circular in shape, with the inside diameter of 4 ft (1.25 m) has been widely adopted. These are provided at every bend, junction, change of gradient or change of diameter of the sewer. The sewer line between the two manholes is laid straight with even gradient. It consists of working chamber, an access shaft & a strong cover on the top. The lower portion of a deep manhole is known as a working chamber and it provides a working space to carry out cleaning and inspection of sewer line. Access shaft provides access to the working chamber. The manhole cover of RCC is provide to cover the opening. 7

8. 2. Drop manhole When it is uneconomical or impracticable to arrange the connection with 60 cm of invert of the sewer and manhole, then vertical shaft is constructed outside the manhole chamber through which the sewage of branch sewer is allowed to enter the manhole. Such a manholes which drop the level of invert of the incoming sewer by providing a vertical shaft are called drop manhole. The main purpose of drop manhole is to avoid the splashing of sewage on the man work. 8

9. 2. Drop manhole Fig. Drop Manhole Source: http://dirtyfluid.blogspot.com/search/label/Sewer%20Appurtenances 9

10. 3. Lamp hole A lamp holes are the opening or holes are constructed in a sewer for the purpose of lowering a lamp inside it. It is a vertical stoneware or concrete pipes which are connected to the sewer line. The pipes are surrounded by concrete to make them stable. At the ground level, the manhole cover with frame is provided to take up the load of traffic. Fig. Lamp hole Source: http://dirtyfluid.blogspot.com/search/label/Sewer%20Appurtenances 10

11. 4. Street Inlets It is an opening through which storm water and surface water flowing along the street are admitted and conveyed to the storm water sewer or combined sewer by means of pipes. These are placed at the road, gutters, generally at street junctions. It should provide in a such way that it will not cause any interference with the traffic. Curb Inlets, Gutter Inlets & Combined Inlets. 11

12. 4. Street Inlets Fig. Curb Inlet Fig. Gutter Inlet Source: http://dirtyfluid.blogspot.com/search/label/Sewer%20Appurtenances 12

13. 5. Catch Basins Catch basins are used to interrupt the flow of sewage before it enters the sewer, causing deposition of suspended grit and sludge and the detention of floating rubbish which could enter and clog the sewer. However, their use is discouraged because of the nuisance due to mosquito breeding apart from posing substantial maintenance problems. At the bottom of the basin space is provided for the accumulation of impurities. Perforated cover is provided at the top of the basin to admit rain water into the basin. 13

14. 5. Catch Basins Fig. Catch Basin Source: http://dirtyfluid.blogspot.com/search/label/Sewer%20Appurtenances 14

15. 6. Flushing Device Arrangement which holds water and then throws it into sewer for flushing it. Sewers need flushing when certain reaches of sewer have unfavorable combination of low slope and low tributary sewage flow i.e. have chances of blockage also placed at dead end point of sewer. Two methods of flushing hand operated flushing operation automatic flushing tanks 15

16. 6. Flushing Device Fig. Automatic Flushing Device Source: http://dirtyfluid.blogspot.com/search/label/Sewer%20Appurtenances 16

17. 7. Sand, grease and oil traps Grease in sewers results in the formation of incrustations that are difficult to remove and cause a substantial loss in the capacity of the sewer. The presence of oil and gasoline has resulted in explosions in the pipes. Grease, oil, and gasoline are removed by traps placed in the plumbing systems. A general feature of grease and oil traps is the provision of a channel which forces the sewage to flow downwards, beneath a free surface, while passing through the trap. Floating grease and oil rise to the surface on the inlet side of the trap, from which they may be cleaned through removable covers on the structures. 17

18. 7. Sand, grease and oil traps Source: https://www.septicmedicaz.com/sand-oil-grit-trap-interceptors.html 17

19. 8. Inverted Siphon A sewer line has sometimes to be laid across a stream, a highway cut, or any other similar obstruction, either below or' above the ground level. When the profile laid below the ground, that portion of the sewer is known as inverted siphon (or, a depressed sewer). This section of sewer lies below the hydraulic grade line, flowing full and under pressure. Source: http://www.engineeringenotes.com/sanitary-engineering/design-of-inverted-siphon-with-diagram-sewer-sanitary-engineering/17143 19

20. 9. Sewer Outlet Storm water and treated water may be discharged into small or large water bodies via sewer outlet. Outlets to small streams are similar to the culverts, consisting of a simple concrete head wall and apron to prevent erosion. Sewers discharging into larger bodies of water are usually extended beyond the banks into fairly deep water where dispersion and diffusion will aid in the mixing sewage with the surrounding water. Source:http ://news.bbc.co.uk/2/hi/ uk_news / england / hampshire /4743629.stm Fig. Sewer Outlet 20

21. 10. Ventilating shaft The ventilating shaft is desirable to prevent the accumulation of dangerous explosive or corrosive gases. The ventilating shaft prevents the creation of pressures (above or below atmospheric) that may break water seal in plumbing traps. In case of stormwater , this can be done by providing ventilating manhole covers. Source: http://www.historywebsite.co.uk/listed/pipecodsall.htm Fig. Ventilating Shaft 21

22. Thank you for the listening!! 22