SEWER APPURTENANCES

SEWER APPURTENANCESINTRODUCTIONIn order to make the process of construction easy and to have efficient working and maintenance.

Sewer system requires various types of appurtenances for their proper functioning and maintenance.

If sewerage system is not properly maintained silt, ashes, grit, oil, fats, etc. will chock the sewer linesSEWER APPURTENANCESManholeCatch basinCleanoutsOil & grease trapInletsLamp holesDrop manholesFlushing tanksInverted siphons

LAMPHOLESAn opening or hole constructed in a sewer for the purpose of lowering a lamp inside.

Purpose-Flushing device.Fresh air inlet.

Location-In narrow lanes change of gradient and slight curves where space is insufficient .If the construction of manhole is difficult.When the sewer length is straight for a considerable distance beyond the usual spacing between manholes.

OIL AND GREASE TRAP

Provided on the sewer line to exclude grease and oil from sewage before it enters the sewer line. Principle. Location. Cleaning. Reasons for removal of oil & grease.

CATCH BASINS

It is a structure in the form of a chamber which is provided along the sewer line to admit or allow the clear rain water free from silt, grit, debris etc. into the combined water. Chambers (75 to 90 cm in dia. And 75 to 90 cm in deep). The outlet pipe of catch basin is fixed about 60 cm above the bottom of catch basin.Purpose-To prevent the entry of silt, grit, debris, etc. contained in the rain water.To prevent the sewer gas.Maintenance It requires a periodical cleaning. It also then forms a breeding place for mosquitoes and causes annoyance to the person passing.Use The catch basins are adopted for the combined sewerage system.

CLEANOUTS

Inclined pipe which is connected to the underground sewer. Working.

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VENTILATORS IN SEWERSVarious gases are produced in the sewers due to decomposition of organic materials of sewage.

cause harm to human health and corrode the sewers reducing their life.

Highly explosive .

ventilation is provided to the sewers lines at every 80-100 mt.

STORM WATER INLETSSTREET INLETS -Opening through which storm water and surface wash flowing along the streets are admitted and conveyed to the storm water sewer by means of pipe.Types-Vertical inlet or curb inlet.Horizontal inlet or gutter inlet.Combine inlet.

Location-The inlets are located or placed by the sides of roads at a distance of about 30 to 60 m. The inlets are connected to nearby manholes by pipe line. The dia. of connecting pipe to street to main street sewer should not be less than 200mm.Openings-least opportunity is given for the storm water to stop. Chances of clogging are brought down to minimum possible extent.The objects that are cause most of the trouble. The cleanliness of footpaths and streets.

INVERTED SIPHONIt is a sewer section which is constructed lower than the adjacent sewer sections and which runs full under gravity with pressure greater than the atmosphere. It will be more appropriate to refer it as a depressed sewer or a sag pipe.Purpose- To carry the sewer line below obstructions such as ground depression, streams, rivers, railway etc.

Wastewater is pushed - siphon by the upstream flow that is at a higher water level than the downstream levelinverted siphon pipes are smaller diameter than the connecting pipes upstream and downstreamVelocity-The self cleaning velocity 1.0 mps for minimum flow to avoid the deposition in the line.

Inlet and outlet chamber- should allow the sufficient room for entry and maintenance of siphon. The outlet chamber is so designed so that to prevent the backflow of sewage into the pipes which are not used at a time of minimum flow.

FLUSHING TANKSIt is a device or an arrangement which is made to hold and then to through water into the sewer for the purpose of flushing it.Approximate quantity require for flushing -Slope200mm250mm300mm0.0502300 lits.2500 lits.3000 lits.0.0751500180023000.01001300150020000.020050080010000.0300400500700

Types-Hand operated flushing tank.Automatic flushing tank.

Purpose-Where it is not possible to obtain self cleaning velocities due to flatness of gradient especially at the top ends of branch sewers which receive very little flow

The flushing can be conveniently accomplished by the use of a fire hydrant or tanker & hose.

Quality of water-It is not required treated water. Untreated can be preferred.

MANHOLES It opening constructed on the alignment of sewer for facilitate a person access to the sewer.

Object

Location

Constructional detail

Rectangular manholes-For the depth of manholes less than 0.90mtr, 900x800mm.For the depth of manholes 0.90 up to 2.5 mtr, 1200x900mm.Arch type manhole

For the depth of 2.5 & above .

Circular manholes- circular manholes are straight down in lower portion and slanting in top portion so as to narrow down the top opening equal to dia. of manhole cover.

For depth above 0.90m and up to 1.65m, 900mm diameter.For depth above 1.65m and up to 2.30m, 1200mm diameter.For depth above 2.30m and up to 9.0m, 1500mm diameter.For depth above 9m and up to 14m, 1800mm diameter.

Inspection chamber-

Water seal of about 100mm and it is provided in the last manhole house drainage system.

Conveys sewage from house to the public sewer.

Trap is to prevent the entry of sewer gases from public sewer line to house drainage.

DROP MANHOLE

When a sewer connects with another sewer, where the difference in level between main line and the invert level of branch line is more than 600mm.

A drop connection shall be provided for which a manhole may be built incorporating a vertical or near vertical drop pipe from the higher sewer to lower sewer. This pipe may be outside the shaft and encased in concrete or supported on brackets inside the shafts. THANK YOU