Building sanitation, sanitory fitting, sewer appurtenances

1. Presentation on
“Domestic Sewage”
By
Prof. Vilas N Nikam
Sandip Polytechnic, nashik
Email: vilas5151@gmail.com

9. 2. flushing cistern.
• Installation of flushing cistern is necessory for
flushing the water closet

18. Traps And Pipes and other components
of house Drainage System
• Following are the main components of House drainage
system.
• Traps: Good Traps should have following Qualities:
• Should provide enough water seal ( around 50 mm)
with large surface area.
• Interiors surface should be smooth so that the flow is
not obstructed which enables self cleansing.
• An assess door should be provided for cleaning the
trap.
• It should be made of non- adsorbent material.

19. Classification of Traps
• Depending upon the shapes the traps are classified
as:
• P-Trap
• Q-Trap
• S-Trap
• Above three types of traps are shown in the
following figures.
• The depth of a Trap Seal would depend upon the
usage of a pipe. The trap seal varies from 25 to 75
mm deep.

20. 20

21. 21
Causes of failure of water seal :-
1. Faulty joints
2. Crack in the bottom of seal
3. Creation of partial vacuum in the sewer fittings
4. Increase in the pressure of sewer gases
5. Non-use for a prolonged period
 Prevention:-
1. Connecting the portion between the soil pipe and trap
by a vent pipe .
2. Use of anti- siphonage pipe in the building

22. Requirement of a good trap :-
1. It should possess a adequate water seal at all times .
2. It should be not absorbent material .
3. The internal and external surface should have smooth
finish so that dirt , etc. Does not stick to it .
4. It should be free from any inside projection , angles ,
contractions, so that flow is not obstructed.
5. It should be self cleansing .
6. It should be simple in construction , cheap and readily
available .
7. It should be provided with suitable access for cleaning.

23. Classification of traps :-
A. Classification according to shape :
1. P – trap :Below wash basin
2. Q – trap: in water closet
3. S – trap : in water closet

24. B. Classification based on use :
1. Floor trap or nahni trap :
A floor trap a commonly known as a nahni trap is used to
collect wash water from floor, kitchen and bathrooms . It forms the starting
point of waste water flow. It is generally made of cast iron .
Location: In the bathroom

25. 2. Gully trap :
These are special type of traps which disconnect sullage drain
from the main drainage system . A well designed gully trap serve two or three
connections from the nahni trap .
Location: at the junction of house drain & public sewer line placed at external
face of wall.

26. 3. Intercepting trap :
The intercepting trap is also known as disconnecting trap or
interceptor . It is provided at the junction of the house drain with the public sewer
or septic tank . It is thus provided in the last man hole of the house drainage
system.
Location: at the junction of house drain & public sewer line.

27. P, Q and S Traps
Q Trap S TrapP Trap

28. P, Q and S Traps

29. Nahni Trap

30. Gully Trap

31. Intercepting Traps

32. Advantage of Intercepting Traps
• Foul Gases of larger municipal sewers are
prevented from entering house drainage
system.
• Harmful pathogens are not entered in house
drains.
• Well designed and contructed interceptors can
quickly remove foul matter of house drain to
muncipal sewers.

33. BUILDING SANITARY DRAINAGE SYSTEMS
• TWO-PIPE SYSTEM - INDPENDENT STACKS FOR SOIL AND
WASTE WATER WITH ASP.
• ONE-PIPE SYSTEM- COMBINED STACK FOR SOIL AND
WASTE WATER WITH ANTI SIPHONAGE PIPE.
• SINGLE STACK SYSTEM- COMBINED STACK FOR SOIL AND
WASTE WATER WITH OUT ANTI SIPHONAGE PIPE.
• SINGLE STACK(PARTIALLY VENTILATED) SYSTEM- VIA
MEDIA BETWEEN ONE PIPE AND SINGLE STACK. ONLY
SOIL TRAPS ARE VENTILATED.

34. Two pipe system

35. TWO PIPE SYSTEM
ADVANTAGES
• ENSURE SEGREGATION OF FOUL SEWAGE FROM WASTE WATER.
• NO DANAGER OF BACKFLOW OF SEWAGE IN WASTE FITTINGS INCASEOF
BLOCKAGE OF SOIL PIPE.
• ENABLES USE OF WASTE WATER DIRECTLY FOR IRRIGATION/GARDENING.
• SEPARATE WASTE WATER STACK PERMITS ARREST OF SOLIDS FROM KITCHEN IN
THE GULLY TRAP THUS PREVENTING THE FROM ENTERING SEWER. GULLY TRAPS
NEEDS TO BE CLEANED PERIODICALLY.
DISADVANTAGES
• DIFFICULT TO INSTALL IN HIGH RISE BUILDINGS WHERE STACKS TERMINATE IN SERVICE
FLOOR OR IN THE CEILING OF THE BASEMENT.
• LONG HORIZONTAL RUNS TO REACH EXTERNAL WALLS /EXTERNAL SEWERS.
• PROVISION OF GULLY TRAP DIFFICULT TO IMPLEMENT IN ABOVE SITUATION.
• REQUIRE MORE SHAFT/DUCT SPACE.
• CONGESTED SHAFT RESULTS IN DIFFICULT TO MAINTAIN SYSTEM.
• USED IN INDIA AS MATTER OF CONVENTION AND CONSERVATIVE APPROACH RATHER
THAN AS A PRAGMATIC APPROACH.

36. ONE PIPE SYSTEM

37. ONE PIPE SYSTEM
ADVANTAGES.
• LARGELY REPLACED TWO PIPE SYSTEM IN MOST DEVELOPED
COUNTRIES.
• FAST BECOMING PREFERRED SYETEM IN OTHER PARTS OF THE
WORLD.
• HIGH QUALITY PIPES,FITTINGS AND INSTALLATION
TECHNIQUES AVAILABLE THESE DAYS.
• CONSTANT FLOW OFWATER ENSURES REDUCTION IN
BLOCKAGE PROBLEM.
• ELIMINATED GULLY TRAPS. THUS PRECLUDES THE NEED TO
CLEAN THEM.
• REQUIRE LESSER SHAFT/DUCT SPACE.
• HIGHLY ECONOMICAL IN TERMS OF COST.
• QUICK TO CONSTRUCT AND COMMISION.
DISADVANTAGES.
• DANGER OF BACK FLOW OF SEWAGE IN WASTE FITTINGS.

38. SINGLE STACK SYSTEM

39. CHOICE OF PLUMBING SYSTEM
AS PER SP:35 (S&T)-1987
• TWO PIPE SYSTEM IS AGE OLD AND SAFE SYSTEM. ADVANTAGEOUS WHERE
WASTE WATER IS RECYCLED FOR USE IN GARDENING ETC. NOT RELEVANT IN THE
CASE OF JAYPEE GREENS.
• REASONING BEHIND THE SEGREGATION OF THE SOIL AND WASTE STACKS HAS
BEEN TO PUT SECOND LINE OF DEFENCE IN THE FORM OF TRAPPED GULLY
AGAINST PASSAGE OF SEWER AIR INTO THE BUILDING VIA WASTE FIXTURES.
• THIS WAS CONSIDERED A SERIOUS DEFECT SINCE THE FOUL AIR FROM WASTE
PIPE INTO A BUILDING MAY BE AS OBJECTIONABLE AS FOUL AIR FROM SOIL
PIPE. IT WAS CONSIDERED THAT THERE IS NO SECOND LINE OF DEFENCE AND
SEPARATE PIPE FOR WASTE WATER IS NOT REQUIRED.
• ONE PIPE SYSTEM IS TO BE PREFERRED WHERE BUILING PROVIDES FOR SUITABLE
GROUPING OF ALL SOIL AND WASTE APPLIANCES AND WHERE ALL TYPES OF
WATERS ARE TAKEN TO A COMMON SEWER TO THE PLACE OF DISPOSAL OR
TREATMENT.
• TRAP SEAL OF 40MM AND 50 MM FOR WASTE AND SOIL WATER RESPECTIVELY
CONSIDERED SUFFICIENT SAFEGUARD.

40. CHOICE OF PLUMBING SYSTEM
AS PER SP:35 (S&T)-1987
CONTD….
 IN ADDITION FOLLOWING SAFEGUARDS ARE TO BE TAKEN:-
 EACH WASTE PIPE CONNECTED ABOVE SOIL BRANCH TO COMMON STACK.
 ALL TRAPS SHALL BE VENTILATED BY LOOP VENTS BY A PIPE NOT LESS THAN 50MM
DIA.
 MODERN TREND IS TO GO IN FOR PARTIALLY VENTILATED ONE PIPE OR SINGLE
STACK SYSTEM.
 IN HIGH RISE BUILDINGS, PARTIALLY VENTILATED ONE PIPE OR SINGLE STACK
SYSTEM IS BEING USED WHERE VENT STACK IS CONNECTED TO THE DRAINAGE
STACK OR THE SOIL APPLIANCES AT EACH OR ALTERNATE FLOOR. FOLLOWING
SAFEGUARDS TO BE TAKEN IS SUCH A SYSTEM:
 VERTICAL DISTANCE BETWEEN WASTE BRANCH AND SOIL BRANCH SHALL NOT BE LESS
THAN 20 CM.
 IF WB/SINK DIRECTLY CONNECTED TO MAIN STACK THEY SHALL HAVE 75MM MIN
WATER SEAL TRAP FOR BRANCH CONNECTION OF LESS THAN 75MM DIA OR 50 MM
FOR BRANCH CONNECTION MORE THAN 75MM DIA.

41. Sewer and its types
• Sewer is a pipe or conduit carrying sewage.
Sewers are usually not flow full (Gravity Flow).
The full flowing sewers are called force main
as the flow is under pressure.

42. Classification based on material used
1. Asbestos Cement (AC) Sewer
2. Brick Sewer
3. Cement Sewer
4. Cast iron (CT) Sewer
5. Steel Sewers
6. Plastic Sewers

43. 1. Asbestos Cement (AC) Sewer
• Types of sewer like Asbestos Cement (AC) Sewers are
manufactured from a mixture of cement and asbestos fiber.
Suitability
• Asbestos Cement (AC) Sewers are suitable for carrying
domestic sanitary sewage.
• Asbestos cement sewer is best as vertical pipe for carrying
sullage from upper floors of multistory buildings (in two
pipe system of plumbing).

44. 2. Brick Sewers
• These types of sewer (Brick Sewers) are made at site and used
for construction large size sewer.
• Nowadays brick sewers are replaced by concrete sewer. Brick
sewers my get deformed and leakage may take place. A lot of
labour work is required.
Suitability
Brick Sewers are very useful for construction of storm sewer or
combined sewer.

45. 3. Cement Concrete
• They may be cast in situ or precast, resistant
to heavy loads, corrosion and high pressure.
These are very heavy and difficult to
transport.
• Suitability
Suitable for small storm drains. Not durable

46. 4. Cast Iron sewers
• These types of sewer are High strength and durability water
tight.
• Cast Iron sewers can withstand high internal pressure and
can bear external load.
Suitability
• When the sewage is conveyed under high pressure
• When the sewer line is subject to heavy external load e.g.
under railway line, foundation wall etc, below highways
• When there is considerable difference in temperature

47. 5. steel sewers
• These types of sewer (steel sewers) are Impervious, light,
resistant to high pressure, flexible.
suitable :
• When;The sewage is carried under pressure
• The sewage has to be carried across a river under water
• The sewer has to cross under a railway track
• They are generally used for outfall and trunk sewers

48. 6.Plastic Sewer
• Nowadays PVC sewers are used for carrying
sewage. Plastic sewers are resistant to
corrosion.
• Such types of sewer are light in weight,
smooth and can be bent easily. But these
types of sewer (Plastic sewers) are having high
co-efficient of thermal expansion and cannot
be used in very hot areas.

49. System of sewarage
• Combined system
• Separate System
• Partially separate system

50. 1.Combined system
Definition : In combined system along with domestic sewage, the run-off resulting
from storms is carried through the same conduit of sewerage system.
Advantages
1.In an area where rainfall is spread throughout a year, there is no need of flushing of
sewers, as self cleansing velocity will be developed due to more quantity because
of addition of storm water.
2. Only one set of pipe will be required for house plumbing.
3.In congested areas it is easy to lay only one pipe rather than two pipes as required in
other systems.
Disadvantages
1.Not suitable for the area with small period of rainfall in a year, because dry weather
,flow will be small due to which self cleansing velocity may not develop in sewers,
resulting in silting.
2.Large flow is required to be treated at sewage treatment plant before disposal,
hence resulting in higher capital and operating cost of the treatment plant.
3. When pumping is required this system is uneconomical.
4. During rains overflowing of sewers will spoil public hygiene.

51. 2.Separate System
Definition : In separate system, separate conduits are used; one carrying sewage and
other carrying storm water run-off.
Advantages
1. As sewage flows in separate pipe, hence the quantity to be treated at sewage
treatment plant is small, resulting in economy of treatment.
2. This system may be less costly as only sanitary sewage is transported in closed
conduit and storm water can be collected and conveyed through open drains.
3. When pumping is required during disposal, this system is economical due to less
flow.
Disadvantages
1. Self cleansing velocity may not developed at certain locations in sewers and hence
flushing of sewers may be required.
2.This system requires laying two sets of pipe, which may be difficult in congested
area.
3.This system will require maintenance of two sets of pipelines and hence
maintenance cost is more.

52. 3. Partially separate system
Definition : In this system part of the storm water especially collected from roofs and
paved courtyards of the buildings is admitted in the same drain along with sewage
from residences and institutions, etc. The storm ater from the other places is
collected separately using separate storm water conduits.
Advantages
1.Economical and reasonable size sewers are required.
2. Work of house plumbing is reduced as rain water from roofs, sullage from
bathrooms and kitchen, etc. are combined with discharge from water closets.
3. Flushing of sewers may not be required as small portion of storm water is allowed
to enter in sanitary sewage.
Disadvantages
1. Increased cost of pumping as compared to separate system at treatment plants and
intermediate pumping station wherever required.
2. In dry weather self-cleansing velocity may not develop in the sewers.

53. Thank you