Week 09 lecture 08 sewage disposal

1. BUILDING SERVICES-II
(PLUMBING)
LECTURE-VIII
SEWAGE
DISPOSAL

2. WASTE DISPOSAL
WASTE
DRY
RUBBISH
ASHES
GARBAGE
SEMI
LIQUID
LIQUID
HUMAN
EXCRETA
/NIGHT SOIL
HOSPITAL &
SLAUGHTER
HOUSE WASTE
SULLAGE
SEWAGE
STORM
WATER

3. SEWAGE DISPOSAL
SEWAGE
It is solid waste consisting of sullage, discharge
from water closets, urinal and hospitals including
night soil
SANITARY
SEWAGE
DOMESTIC
SEWAGE
From residential
areas, offices,
institution etc.
INDUSTRIAL
SEWAGE
From industries
(trade waste)
STORM SEWAGE
It is any surface
water including rain
water

4. SEWAGE DISPOSAL
SEWAGE DISPOSAL
Natural method Artificial Method
Dilution into
water
Land
treatment
Primary
Treatment
Secondary
Treatment

5.  Suitable for the areas situated near large rivers or sea.
 Disposal of sewage by discharging into water courses such as
streams, rivers or water bodies etc.
Disposal by DILUTION
 The sewage to be disposed off, may
be raw or partially treated.
 While discharging sewage in water
body, it should be ascertained that
water is not polluted to such an
extent that it becomes unfit for any
other use.

6.  The sewage, in due course of time, gets purified
automatically by the self purification capacity of water.
 The quantity of pure natural water required for the process
of self purification should be about 6-14 times the volume of
the sewage disposed.
 Diluting water must be rich in oxygen content for Dilution.
 Diluting waters are not become a source of water supply for
at least some distance from the point of disposal.

7.  Raw sewage or partly treated sewage is evenly spread on the
surface of land.
 Water in the sewage percolates in the ground and suspended
solids remains at the surface of the ground.
LAND TREATMENT
ADVANTAGE
 Adds manure to the ground.
 Increases fertility of land.
 Water pollution is reduced.

8. DISADVANTAGES
 Additional land is required.
 If land is made up of heavy, sticky and fine grained soils, its
voids get chocked and may create nuisance.
 Sanitary reasons may not permit growing of crops on sewage
farms.

9. Sewage
treatment
Preliminary
treatment
/screening
Primary
Treatment
Secondary
treatment
 Filtration
 Activated
sludge
process
Grit chambers
Detritus tank
Skimming tank
Plain
sedimentation tank
 Screens are provided
to remove floating
matter of large size
which may, otherwise
choke up the small
pipes or affect the
working of sewage
pumps.

10. PRELIMINARY
TREATMENT /SCREENING
 Screens are provided to
remove floating matter
of large size which may,
otherwise choke up the
small pipes or affect the
working of sewage
pumps.

11. GRIT CHAMBERS are provided to remove the heavier inorganic
matter such as grit, sand, etc. from sewage.
DETRITUS TANK is a grit chamber in which the velocity of flow is
further reduced so that organic matter along with the grit settle down
at the bottom.
SKIMMING TANKS are provided to remove floating substances such as
grease, oil soap etc.
Grit chambers
Detritus tank
Skimming tank
Plain sedimentation
tank

12. FILTRATION in this effluent is
made to pass through the
filtering media. Aerobic
bacteria present in the media
carries out the oxidation of
organic matter caught within
the particles of filtering
materials.
SECONDARY TREATMENT
 Filtration
 Activated sludge process

13. Activated Sludge Process
 Filtration
 Activated sludge process
Primary
Clarifier
Aeration
tank
Secondary
Clarifier
Sludge
digestion tank
Sludge drying
beds
Influent
Extra
Recirculated
Effluent