about waste definition methods to dispose sewage and its treatment

1. 1

2. SOLID WASTE

3. Some terms we need to know
REFUSE:
Solid or semisolid waste matter produced in the normal course of
human activities. Generated from street sweepings, markets, stable
litter, industrial refuse, commercial refuse, etc.
RUBBISH:
Solid wastes originating in houses, commercial establishments,
industries, excluding garbage and ash.
GARBAGE:
Animal & vegetable wastes resulting from the handling, storage,
sale, preparation, cooking and serving of food.
ASH:
Residue from burning of wood, coal, charcoal and other combustible
materials used for cooking and heating purposes in houses, industries
etc.

4. • Street refuse
• Market refuse
• Stable litter
• Industrial refuse
• Domestic refuse
Sources of solid wastes
In most of the countries the per
capita daily solid waste produced is
between 0.25 to 2.5 Kg

5. • Galvanized steel dust bin with cover (for
households) – 0.05 to 0.1 cubic feet per capita
per day.
– A bin with capacity of 1.5 cubic feet for a family of 5
members if collection is done every 3 days.
• Public bins.
Storage of solid wastes

6. • House-to-house collection
• Mechanical transport
• Dustless refuse collector
Collection of solid wastes

7. Methods of solid waste disposal
INSANITARY METHODS
1. Hog feeding
2. Dumping
SANITARY METHODS

8. 1. Sanitary landfill/ Controlled tipping
2. Composting
3. Incineration
4. Manure pits
5. Burial
6. Biogas plant
SANITARY METHODS
Methods of solid waste disposal

9. INSANITARY METHODS
Dumping
– Refuse dumped in low lying areas
– Bacterial action over time, decreases volume of refuse
which is gradually converted into humus
– Disadvantages
• Smell
• Unsightly appearance
• Free access to flies, rodents, hogs, dogs etc.
• Dispersal by wind
• Pollution of surface and ground water

10. Dumping

11. 1. Sanitary landfill / Controlled
tipping
–Laying of dry and condensed refuse in a
trench or other prepared area with
intervening earth coverings.
–Anaerobic digestion of the refuse takes
place. The process takes 4-6 months to
complete.
SANITARY METHODS

13. 2-3meter
4-12 meter

14. • Trench method
– Level ground
– Trenches 4-12 m wide, 2-3 m deep
– Refuse is compacted and then covered with
excavated earth
• Ramp method
– Sloping terrain
• Area method
– Land depressions, disused quarries, pits
– May need soil from outside sources to cover the
compacted refuse

15. 2. Composting
–Method of combined disposal of refuse
and nightsoil or sludge.
–Organic matter breaks down under
bacterial action, producing “compost” –
used as manure.
SANITARY METHODS

16. BANGALORE
METHOD
MECHANICA
L
COMPOSTIN
G
VERMI-
COMPOSTIN
G
Three methods of composting

17. Bangalore method
Anaerobic composting; also called “Hot
fermentation process”
IISc, Bangalore – Indian Council of Agriculture
Research

18. 800 metre

19. 90
cm
4.5 – 10 m
A Trench excavated for
composting

20. Anaerobic
4-6 months
Humus
NIGHTSOIL
15
cm
5
cm
15
cm
5
cm
25
cm
REFUS
E
REFUS
E
NIGHTSOIL
REFUS
E
Earth
NIGHTSOIL

21. Mechanical composting
Refus
e
Pulverizing
equipment
Pulverized refuse +
Sewage/Sludge/Nightsoil
Incubation
(Temperature, pH, Aeration, Moisture controlled)
Complete
composting
Screening
4-6 weeks

22. Vermicomposting
A method of garbage disposal
Garbage Earthworms
2-3 months
Compost

23. 3. Incineration
–Suitable for areas where land is not
available for sanitary landfill
–Example: Hospitals
–Disadvantages:
•Expensive
•No useful by-product
•Air pollution
SANITARY METHODS

24. 4. Manure pits
–Used in rural households
–Covered with earth after each days
dumping
–Two pits
–Within 5-6 months decomposed refuse
which is used as fertilizer
SANITARY METHODS

25. 5. Burial
–Suitable for small settlements/camps
–Decomposed matter may be ready for
use as manure within 4-6 months
SANITARY METHODS
1.5 m
2m
20-30
cm
40 cm
1 m
200 persons
1 week

26. 6. Biogas plant
• Biogas is produced by the
anaerobic breakdown of
solid waste /excreta.
• Biogas (Methane, CO2,
Hydrogen) can be used as a
fuel for any heating purpose,
such as cooking.
SANITARY METHODS

27. EXCRETA

28. Spread of disease from excreta

29. Sanitation barrier

30. Methods of excreta disposal
INSANITARY METHODS
1. Bucket type
2. Conservancy system/Cartage
SANITARY METHODS
WATER CARRIAGE SYSTEM

31. 1. Bore hole latrine
SANITARY METHODS
Methods of excreta disposal
2.Dug well/pit latrine
3. Water seal type
of latrine
a) P.R.A.I
b) R.C.A
c) Sulabh
sauchalya
4. Septic tank
5. Aqua privy

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3.latrine suitable for
camps
i. Shallow trench
latrines
ii. Deep trench latrine
iii.Pit latrine
iv.Bore hole latrine

33. Water carriage system and
sewage treatment
A) PRIMARY TREATMENT
• screening
• Removal of grit
• Plain sedimentation
B ) SECONDARY TREATMENT
• Trickling filters
• Activated sludge process
c) OTHER METHODS
a) Sea outfall b) river outfall
c) Sewage farming d) oxidation ponds 33

34. INSANITARY METHODS OF
EXCRETA DISPOSAL

35. 1. Open defecation
2. Cartage (Conservancy
system)
•Example: Bucket latrine
•Disadvantages:
Smell
Flies
Health risk to people handling
the excreta
Health risk from food crops
fertilized with raw excreta
Bucket
latrine

36. SANITARY METHODS OF
EXCRETA DISPOSAL

37. 9b. Bore Hole Latrine
• Introduced in India by Rockefeller Foundation in
1930’s as a component of hookworm control
programme.
• Consists of a circular hole dug by an equipment
called “auger”.

38. 20feet
16 feet

39. 1a. Simple pit latrine

40. Locationofapitlatrine

41. Advantages&
Disadvantages
• Advantages:
– Easy and cheap to construct
– Slab and shelter can be reused
– Excreta are isolated
• Disadvantages:
– Unpleasant odors
– Flies

42. • A circular pit about 75cm in diameter
and 3-3.5m deep is dug into ground for
reception of nightsoil.
• The pit lined with pottery rings to
prevent of soil reenter.
• Concrete squatting plate is placed on
top.
• Merits: 1. easy to construct
• 2. longer life
1b. Dug well latrine

43. 0.5 m
Semi
dark
Shelter

44. Water Seal Latrine:
• Hand flushed water seal latrine.
• Water seal
• Types of water seal:
44

45. Waterseallatrine

46. The Water Seal

47. 2a. Direct & Indirect WS
Latrine
Direct Indirect

48. 2c. PRAI & RCA Latrine
• PRAI Latrine was developed by the Planning,
Research & Action Institute, Lucknow
• RCA latrine was developed by the Research
Cum Action project of the Ministry of Health

49. The RCA Latrine
1. Location
2. Squatting plate
3. Pan
4. Trap
5. Connecting pipe
6. The pit
7. Superstructure
8. Maintenance
9. Modifications

50. Location
•Depends on porosity of soil and ground water level
•Usually, at least 15 m away from water source
Squatting plate
•Made of impervious material (cement concrete)
•3’x3’x2”
•Raised footsteps
Pan
•Receives nightsoil, urine and water
Trap
•A bent pipe connected to the pan
•Holds water and serves as a water seal (2 cm depth)

51. Connecting pipe
•Needed when pit is sited away from squatting plate
•Not needed in Direct type RCA Latrine
•3.5” diameter with a bend at the end
The pit
•Covered, rectangular/circular
•75 cm diameter, 3-3.5 m deep
• Underneath squatting plate(Direct) or offset (Indirect)
Superstructure
Maintenance
•Regular cleaning of the squatting plate
•Flushing with 1-2 lts of water after every use

52. Modifications
•Using prefabricated squatting plate/pan made of china
clay
•Using a septic tank instead of the pit

53. Squatting plate
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54. Pan and connecting
pipe 54

55. • The aquaprivy is a water tight tank filled with
water into which excreta fall via a drop pipe,
connected to a seepage pit (soakaway) to
dispose of sullage and effluent.
• Drop pipe must reach below surface of the
water.
• Night soil undergoes purification by anerobic
digestion
Vent open on top
Sludge removed at end.
4. Aqua privy

56. The AQUAPRIVY

57. Advantages&
Disadvantages • Advantages:
– Cannot be blocked with bulky anal cleaning
material
– Nil problem with odor or flies
– Can be connected to a sewerage system at a
later date
• Disadvantages:
– Expensive to build
– Need large volumes of water to work
– Water seal may be hard to maintain
– Tanks must be emptied about every 3 years

58. • Septic tanks are watertight chambers (single,
double or multi chambered) which receive
excreta and wastewater.
• They are connected to a soakaway which
receives liquid overflowing from the tank.
5. Septic Tank

61. WorkingofSepticTank
• Solids (“sludge”) settle down and are
purified by anaerobic digestion.
• The liquids (“effluent”) undergoes
aerobic oxidation in the upper layers of
the soil, outside the septic tank proper.

62. • The sludge is reduced in volume and a portion of
solids is transferred to liquids and gases which
rises to surface forming bubble.
• Liquid passes out called effluent which percolates
into soil by open ended pipes laid in trenches.
• Aerobic bacteria attack organic matter and
convert to end products .
•
• Complete purification of sewage.
62

63. Advantages&
Disadvantages • Advantages:
– Isolation and treatment of excreta
– No odor or fly problems
– May be connected to sewerage system at a
later date
• Disadvantages:
– High cost of construction
– Need for periodic mechanical emptying
– Need for large volumes of flushing water
– Only suitable where flush toilets are used

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65. • A low cost, water seal type of latrine connected
to a 3’x3’x3’ pit. It is a modified handflush latrine
with a specially designed pan and trap – needs
very little water for flushing.
• Sulabh International, an NGO, maintains Sulabh
Community Latrines – ‘pay-and-use system – in
many parts of India.
6. Sulabh Shauchalaya

66. SHALLOW TRENCH
LATRINE
• Simple trench dug with ordinary
tools.
• Trench is 30cm wide 90-150cm
deep.
• Separate for men and women
• Earth piled up a side and people
instructed to cover up earth after
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67. Shallow Trench latrine
Access
path
Handwashing
facility
Dug soil (for back filling)
Trench depth
approx. 150
mm
Poles to attach
screening
Security screening
Superstructure

68. Plan View
1.5m
5 m 4 m
Approx
.
300mm

69. DEEP TRENCH LATRINE:
• Used for camps in longer duration
• Trench is 1.8-2.5m
• 75-90cm wide
• Squatting plate is provided.
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70. DeepTrenchlatrine
Superstructure

72. Modern sewage treatment.
• A) primary treatment
• B) secondary treatment
•
• PRIMARY TREATMENT
• 1.Screening
• 2. Grit Chamber
• 3. Primary Sedimentation.
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74. • Sewage made flow across tank , spends 6-8hrs in
tank
• Purification takes place mainly by sedimentation
• 50-70% settle down under influence of gravity.
Coli form organism formed called ‘sludge’
Biological action takes place were micro-organism
attack sewage
Sewage attack complex organic solids and break them
74

75. • Simpler soluble substance ammonia
• Contain grease and fat that come up
called scum
• Then it is treated with lime ,aluminium
sulpahte and ferrous sulphate.
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76. Secondary treatment:
• Types
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ACTIVATED
SLUDGE
PROCESS

77. Oxygen pond
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