Sewage Management Flashcards
is waste water from a
community, containing solid and liquid excreta, derived
from houses, street and yard washings, factories and
industries. I
Sewage or black water
The pipes through which sewage flows are known as
and the network of such pipes is known as
sewerage
sewers
The health hazards of improper excreta management are
- Soil pollution
- Water pollution
- Contamination of foods and
- Propagation of flies.
most important way to break fecal-borne disease life cycle
Segregation of faeces (Sanitation
barrier)-through sanitary disposal
of faeces,
Methods of excreta disposal can be
divided into two
. Methods applicable to unsewered
areas
2. Methods applicable to sewered areas
Methods of excreta disposal applicable to unsewered
area
-Service and non service types
.Non-Service Type
a) Open defecation
b) Shallow pit
c) Overhung latrine
d) Sanitary latrines-Bore hole latrine, Dug well or pit latrine (Simple pit latrine,
Ventilated Improved Pit (VIP) latrine), Septic tank and soakaway pit, Water-seal
type of latrine, Aqua privy
e) Latrines suitable for camps and temporary use
a)Chemical closet
b)Shallow trench latrine
c) Deep trench latrine
Service Type (Conservancy System )
Bucket or Pail Latrines
Methods of excreta disposal
applicable to sewered area
- Water carriage system and sewage treatment
- Other methods of sewage disposal
a) Sea outfall
b) River outfall
c) Sewage Farming / Land Treatment
d) Oxidation Ponds
e) Oxidation Ditches
f) Aerated lagoons
The collection and removal of nightsoil from bucket or pail
latrines by human agency is called-, and the latrines are called -
❖ The nightsoil is transported in - to the place of
final disposal, where it is disposed of by - and -
❖ Service latrines are a source of filth and insanitation.
❖ They have all the drawbacks and faults which tend to
perpetuate the cycle of faecal-borne diseases in the
community.
❖ The nightsoil is exposed to flies; there is always -
service type or
conservancy system
[15/11, 9:14 pm] Torikems: “nightsoil carts”
[15/11, 9:14 pm] Torikems: (i) composting or (ii)
burial in shallow trenches.
[15/11, 9:15 pm] Torikems: cycle of faecal-borne diseases
[15/11, 9:15 pm] Torikems: possibility of water and soil pollution.
[15/11, 9:16 pm] Torikems: corrosion and require
frequent replacement
SHALLOW PIT People working on farms may dig a small hole each time they
defecate and then cover the excreta with soil.
❖This is sometimes known as the -
❖Pits about - may be used for several weeks.
❖Excavated soil is heaped beside the pit and some is put over
the excreta after use.
CAT method
300mm deep
Bore hole latrine
➢The latrine consists of a
circular hole - in
diameter dug vertically into
the ground to a depth of -, most commonly 6m.
➢ A concrete squatting
plate with a - is
placed over the hole.
➢A suitable enclosure is
put up to provide privacy
[15/11, 9:29 pm] Torikems: 30cm to 40cm 4m to 8m most commonly 6m
[15/11, 9:30 pm] Torikems: central opening and foot rests
Simple pit latrine
➢ A circular pit about -
is dug into the ground for reception of the nightsoil.
➢ The pit may be lined with-
➢ A concrete squatting plate is placed on top of the pit, and
the latrine is -
75cm in diameter and 3 to 3.5 m deep pottery rings to prevent caving in
of the soil enclosed with a superstructure
Sanitary latrines
❑Ventilated Improved Pit (VIP) latrine (1) The concrete squatting plate must have openings for the
squatting chute and the vent pipe.
Septic tank and soakaway pit
❖Septic tank is - into which
household sewage is stored.
❖A soakaway is a system comprised of a hole dug in the
ground and filled with - and - stones This allows
surface water that would - to soak
back down into the earth
[15/11, 9:41 pm] Torikems: water-tight masonry tank rubble and coarse stones otherwise begin to pool
[15/11, 9:46 pm] Torikems: Latrines suitable for camps and temporary use includes:
[15/11, 9:47 pm] Torikems: -Chemical closet -shallow treanch latrines -deep trench latrines
Shallow trench latrine
Latrines suitable for camps and
temporary use (2)
❖ This is simply a trench dug with ordinary tools.
❖ The trench is -wide and - deep
❖ Its length depends on the number of users: -
❖ Separate trenches should be provided for men and women.
❖ The earth from the trench should be -
❖ People should be instructed to cover faeces with earth each
time they use the latrine
30cm wide and 90-150cm deep 3-3.5m are
necessary for 100 people.
❑Deep trench latrine
Latrines suitable for camps and
temporary use (3)
❖ This type of latrine is intended for -,
from a few weeks to a few months.
❖ The trench is -wide and - deep
❖ Depending upon the local customs, a seat or a squatting
plate is provided.
❖ A superstructure is built for privacy and protection
for camps of longer duration 1.8 to 2.5m deep and 75-90cm wide
METHODS APPLICABLE TO SEWERED
AREAS
❑WATER CARRIAGE SYSTEM
❖Elements of Water Carriage System
METHODS APPLICABLE TO SEWERED
AREAS
❑WATER CARRIAGE SYSTEM
❖Elements of Water Carriage System
list 4
❑SEWAGE TREATMENT
❖Modern Sewage Treatment Plant
❖Aquatic Treatment Systems
❑SEWAGE TREATMENT
list 2
❖Elements of Water Carriage System
1.Household sanitary fittings (plumbing system in
buildings)
2.House sewers
3.Street sewers or Trunk sewers
4.Sewer appurtenances: manholes, traps, etc ❑SEWAGE TREATMENT
❖Modern Sewage Treatment Plant
❖Aquatic Treatment System
Sewer appurtenances ➢Manholes are openings built into sewerage system to -
➢Locations:
✓Whenever there is -
✓Meeting point of two or more sewers
✓Distances of -
permit
inspection, repairs and cleaning.
change in the direction of sewers
f 100metres in long straight runs
Sewer appurtences ❖Traps
➢Traps are designed to
prevent foul gases entering
houses and to remove sand,
grit and grease from sewage.
➢They are placed in 3
situations
. Under the basin of water
closets
2. Where house drain joins
public drain (intercepting
trap)
3. Where surface water
enters the drain
Modern Sewage (Wastewater) Treatment Plant
❑Primary Treatment
-Screening
-Grit chamber
-Primary sedimentation
❑Secondary Treatment
-Biological Treatment-Trickling filter method
-Activated sludge process
-Secondary Sedimentation
❑ Sludge Disposal
-Digestion or
-Sea disposal or
-Land disposal
❑ Effluent Disposal
-Disposal by dilution
-Disposal on land
by the action of anaerobic and aerobic y by screening and partly by sedimentation aerobic oxidation
SECONDARY TREATMENT
❑Trickling filter (1)
❖The trickling filter or percolating filter is a bed of crushed
stones or cinker, -
depending upon the size of the population.
❖The effluent from the primary sedimentation tank is
sprinkled uniformly on the surface of the bed by a revolving
device.
❖The device consists of hollow pipes each of which have a
row of holes.
❖The pipes keep rotating, sprinkling the effluent in a thin
film on the surface of the filter.
1 to 2 m deep and 2 to 30 m in diamete
Activated sludge process (1)
❖Activated sludge process is the modern method of
purifying sewage in place of the trickling filter.
❖The heart of the activated sludge process is the -
❖The effluent from the primary sedimentation tank is
mixed with sludge drawn from the final settling tank ( also
known as activated sludge or return sludge, this sludge is -).
❖The proportion of activated sludge to the incoming
effluent is of the -
aeration
tank. a
rich culture of anaerobic bacteria 20 to 30 per cent.
Activated sludge process (2)
❖The mixture is subjected to aeration in the aeration
chamber for about-
❖The aeration is accomplished either by mechanical
agitation or by forcing compressed air continuously from the
-
❖This latter method, also known as - is
considered a better method of aeration.
❖During the process of aeration the organic matter of the
sewage gets oxidized into carbon dioxide, nitrates and
water with the help of aerobic bacteria in the activated
sludge.
6 to 8 hours. bottom of the aeration tank diffuse aeration”
