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DISPOSAL OF EXCRETA
Health hazards of improper excreta
disposal
• Soil pollution
• Water pollution
• Contamination of foods
• Propagation of f...
Spread of disease from excreta
Sanitation barrier
Methods of excreta disposal
Unsewered areas
• Service type latrines( conservancy system)
• Non service type( sanitary latr...
Non service type( sanitary latrines)
• Bore hole latrine
• Dug well latrine
• Water seal latrine
PRAI type
RCA type
Sul...
Latrines suitable for camps and
temporary use.
Shallow
trench
latrine
Deep
trench
latrine
Pit
latrine
Bore
hole
latrine
Primary
treatment
• Screening
• Removal of grit
• Plain
sedmentation
Secondary
treatment
• Trickling of
filters
• Activate...
Cartage (Conservancy system)
•Example: Bucket latrine
•Disadvantages:
oSmell
oFlies
oHealth risk to people handling the
ex...
Criteria for a sanitary latrine
• Excreta should not contaminate the ground and
surface water.
• Excreta should not pollut...
Bore hole latrine
• First introduced by Rockfeller Foundation during 1930
in campaigns of hook worm control.
• The latrine...
Bore hole latrine
30-40 cm diameter
4 to 8 m depth
Bore hole latrine
Merits
• No need for the services of a sweeper for daily removal of night soil.
• Unsuitable for fly bre...
Dugwell latrine
• A circular pit about 75 cm in diameter and 3 to
3.5 m deep.
• The pits may be lined with pottery rings t...
Dugwell latrine
• 75 cm diameter
3 to 3.5 m deep
Dugwell latrine
Advantages
• It is easy to construct and no special equipment
is needed to dig the hit.
• The pit has a lo...
Water seal latrine
Two types
• The PRAI type evolved by Planning, Research
and Action Institute, Lucknow
• The RCA type de...
Essential Features of RCA latrine
Location
Squatting
plate
Pan
Trap
Connecting
pipe
Dug well
Superstructure Maintenance
RCA latrine
• Location
15m
Squatting plate
• Made of an impervious material
• It is made of cement concrete
with minimum dimensions of
90 cm square a...
Pan and Trap
42.5cm
Pan and Trap
• The length 42.5cm. The width of the front portion of the
pan has a minimum of 12.5 cm and the width at its ...
• Connecting pipe
Connecting pipe 7.5 cm in diameter and at least 1m in
length with a bend at the end.
Dug well
The dug we...
• Superstructure
• The desired type of superstructure may be
provided for privacy and shelter.
• Maintenance
• People shou...
SEPTIC TANK
Features of a septic tank
Capacity The minimum capacity of a septic tank
should be at least 500 gallons
Length The length ...
Features of a septic tank
Air space A minimum air space of 30cm between the level of
liquid in the tank and the undersurfa...
Septic tanks
Operation and maintenance
• The use of soap water and disinfectants such as phenol
should be avoided.
• Contents of the se...
• It consists of a water
tight chamber filled with
water
• A short length of a drop
pipe from the latrine floor
dips into ...
Advantages&Disadvantages • Advantages:
– Cannot be blocked with bulky anal cleaning material
– Nil problem with odor or fl...
SULAB SHAUCHALAYA
• The invention of a Patna
based firm
• It consists of specially
designed pan and a water
seal trap.
• I...
LATRINES SUITABLE FOR TEMPORARY USE AND
CAMPS
Shallow trench
latrine
• The trench is
30cm wide and
90-150cm deep.
• Its le...
The trench is 1.8 to 2.5 m deep and 75-90cm wide.
WATER CARRIAGE SYSTEM
Types
Combined sewer system
Separate sewer system.
Elements of water carriage system
• Household sanitary fittings
• House sewers
• Street sewers or trunk sewers
• Sewer app...
Household sanitary fittings
Two types
• Indian squatting type
• The western commode
type
SEWAGE
SEWAGE
• Sewage is waste water from a community
containing solid and liquid excreta .
• The average amount of sewage which...
Health aspects
• Creation of nuisance, unsightliness and pleasant
odours.
• Breeding of flies and mosquitoes
• Pollution o...
Composition of sewage
WATER
99.9%
SOLIDS
0.1%
SEWAGE
Aims of sewage purification
• To stabilize the organic matter so that it can be
disposed off safely.
• To convert the sewa...
Strength of sewage
• Biochemical oxygen demand (BOD)
• Chemical oxygen demand(COD)
• Suspended solids
Biochemical oxygen demand (BOD)
• It is defined as the amount of oxygen absorbed by a
sample of sewage during a specified ...
Chemical oxygen demand(COD)
• The COD test measures the oxygen equivalent
of that portion of the organic matter in a
sampl...
Suspended solids
• The amount of suspended solids in domestic
sewage may vary from 100 to 500 ppm.
• If the amount of susp...
Decomposition of organic matter
Aerobic
process
Anaerobic
process
Primary
treatment
• Screening
• Removal of grit
• Plain
sedmentation
Secondary
treatment
• Trickling of
filters
• Activate...
MODERN SEWAGE TREATMENT
Screen Grit
Chamber
Final
Sedimentation
Tank
Biological
Treatment
Primary
Sedimentation
tank
Sludg...
Primarytreatment
• Screening
The screen
consists of
vertical or
inclined steel
bars usually set
5cm apart.
Primarytreatment Grit chamber
• This chamber is
approximately 10 to 20
m in length,
• it is so designed as to
maintain a c...
Primarytreatment Primary sedimentation
• It is a very large tank
holding from ¼ to 1/3 the
dry weather flow.
• Flow very s...
Secondary treatment
Trickling
filter
method
Activated
sludge
process
The trickling filter
• The trickling filter or
percolating filter is a
bed of crushed stones
or cinker, 1 to 2 m deep
and ...
Activated sludge process
• The effluent is mixed with sludge drawn from the final settling
tank.
• The mixture is subjecte...
Activated sludge process
Secondary sedimentation
• Detained fro 2-3 hours.
• The sludge that collects in the secondary
sedimentation tank is called...
Sludge digestion
• Digestion
• Sea disposal
• Land
Digestion
• Incubated under favorable conditions of temperature
and pH
• Undergoes anaerobic auto digestion
• Complex soli...
Disposal of effluent
Disposal by dilution
• Diluted in the body of water and impurities are oxidized by
the dissolved oxyg...
OTHER METHODS
Sea
outfall
River
outfall
Land
treatment
Oxidation
pond
Oxidation
ditches
Sea outfall
River outfall
Land treatment (sewage farming)
Oxidation pond
• Open shallow pool 1 to 1.5m depth with an inlet and
outlet.
• comprise algae, certain type of bacteria wh...
Oxidation ditches
Role of Nurse
• Survey
• Health education
• Construction of disposal units and supervision
• Evaluation
Thank you
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Disposal of excreta

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Excreta disposal methods

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Disposal of excreta

  1. 1. DISPOSAL OF EXCRETA
  2. 2. Health hazards of improper excreta disposal • Soil pollution • Water pollution • Contamination of foods • Propagation of flies
  3. 3. Spread of disease from excreta
  4. 4. Sanitation barrier
  5. 5. Methods of excreta disposal Unsewered areas • Service type latrines( conservancy system) • Non service type( sanitary latrines) • Latrines suitable for camps and temporary use.
  6. 6. Non service type( sanitary latrines) • Bore hole latrine • Dug well latrine • Water seal latrine PRAI type RCA type Sulab shauchalaya • Septic tank • Aqua privy
  7. 7. Latrines suitable for camps and temporary use. Shallow trench latrine Deep trench latrine Pit latrine Bore hole latrine
  8. 8. Primary treatment • Screening • Removal of grit • Plain sedmentation Secondary treatment • Trickling of filters • Activated sludge process Other methods • Sea out fall • River outfall • Sewage farming • Oxidation ponds Sewered areas
  9. 9. Cartage (Conservancy system) •Example: Bucket latrine •Disadvantages: oSmell oFlies oHealth risk to people handling the excreta oHealth risk from food crops fertilized with raw excreta Bucket latrine
  10. 10. Criteria for a sanitary latrine • Excreta should not contaminate the ground and surface water. • Excreta should not pollute the soil. • Excreta should not be accessible to flies, rodents, animals • Excreta should not create a nuisance due to odor or unsightly appearance
  11. 11. Bore hole latrine • First introduced by Rockfeller Foundation during 1930 in campaigns of hook worm control. • The latrine consists of a circular hole 30 to 40cm in diameter, dug vertically into the ground to a depth of 4 to 8 m, most commonly 6m. • A concrete squatting plate with a central opening and foot rests is placed over the hole. • A suitable enclosure is put up to provide privacy
  12. 12. Bore hole latrine 30-40 cm diameter 4 to 8 m depth
  13. 13. Bore hole latrine Merits • No need for the services of a sweeper for daily removal of night soil. • Unsuitable for fly breeding • If located 15 m away from source of water supply, there should be no danger of water pollution. Demerits • Small capacity. • A special, the auger is required for the construction which may not be readily available. • In many places, the subsoil water is high and the soil loose with the result it may be difficult to dig a hole deeper than 3m.
  14. 14. Dugwell latrine • A circular pit about 75 cm in diameter and 3 to 3.5 m deep. • The pits may be lined with pottery rings to prevent caving in of the soil. • A concrete squatting plate is placed on the top of the pit and the latrine is enclosed with a superstructure.
  15. 15. Dugwell latrine • 75 cm diameter 3 to 3.5 m deep
  16. 16. Dugwell latrine Advantages • It is easy to construct and no special equipment is needed to dig the hit. • The pit has a longer life than borehole latrine because of greater capacity.
  17. 17. Water seal latrine Two types • The PRAI type evolved by Planning, Research and Action Institute, Lucknow • The RCA type designed by the Research cum action projects in Environmental sanitation of the Ministry of Health.
  18. 18. Essential Features of RCA latrine Location Squatting plate Pan Trap Connecting pipe Dug well Superstructure Maintenance
  19. 19. RCA latrine • Location 15m
  20. 20. Squatting plate • Made of an impervious material • It is made of cement concrete with minimum dimensions of 90 cm square and 5 cm thickness at the outer edge. • There is a slope half inch towards the pan
  21. 21. Pan and Trap 42.5cm
  22. 22. Pan and Trap • The length 42.5cm. The width of the front portion of the pan has a minimum of 12.5 cm and the width at its widest portion is 20cm. • The trap is bent pipe about 7.5cm in diameter and is connected with the pan. • It holds water and provides the necessary water seal. • The water seal is the distance between the level of water in the trap and the lowest point in the concave upper surface of the trap. • The depth of the water seal in the RCA latrine is 2cm.
  23. 23. • Connecting pipe Connecting pipe 7.5 cm in diameter and at least 1m in length with a bend at the end. Dug well The dug well or pit is usually 75 cm in diameter and 3 to 3.5 m deep and is covered.
  24. 24. • Superstructure • The desired type of superstructure may be provided for privacy and shelter. • Maintenance • People should be educated to flush the pan after use with adequate quantity of water.
  25. 25. SEPTIC TANK
  26. 26. Features of a septic tank Capacity The minimum capacity of a septic tank should be at least 500 gallons Length The length is usually twice the breadth. Depth The depth of aseptic tank is from 1.5 to 2m. Liquid depth The recommended liquid depth is only 1.2m.
  27. 27. Features of a septic tank Air space A minimum air space of 30cm between the level of liquid in the tank and the undersurface of the cover. Bottom The bottom is sloping towards the inlet end. Inlet and outlet There is an inlet and outlet which is submerged. Cover The septic tank is covered by a concrete slab of suitable thickness and provided with a manhole. Retention period Septic tanks are designed to allow a retention period of 24 hours.
  28. 28. Septic tanks
  29. 29. Operation and maintenance • The use of soap water and disinfectants such as phenol should be avoided. • Contents of the septic tank should be removed at least once in a year. This operation is called desludging and it is disposed by trenching. • Newly built septic tanks are first filled with water up to the outlet level and then seeded with ripe sludge drawn from another septic tank
  30. 30. • It consists of a water tight chamber filled with water • A short length of a drop pipe from the latrine floor dips into the water. 4. Aquaprivy
  31. 31. 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
  32. 32. SULAB SHAUCHALAYA • The invention of a Patna based firm • It consists of specially designed pan and a water seal trap. • It is connected to a pit 3 feet square and as deep.
  33. 33. LATRINES SUITABLE FOR TEMPORARY USE AND CAMPS Shallow trench latrine • The trench is 30cm wide and 90-150cm deep. • Its length depend on the number of users;3-3.5 m for 100 people.
  34. 34. The trench is 1.8 to 2.5 m deep and 75-90cm wide.
  35. 35. WATER CARRIAGE SYSTEM Types Combined sewer system Separate sewer system.
  36. 36. Elements of water carriage system • Household sanitary fittings • House sewers • Street sewers or trunk sewers • Sewer appurtenances; manhole, traps etc.
  37. 37. Household sanitary fittings Two types • Indian squatting type • The western commode type
  38. 38. SEWAGE
  39. 39. SEWAGE • Sewage is waste water from a community containing solid and liquid excreta . • The average amount of sewage which flows through the sewerage system in 24 hours is called the dry weather flow.
  40. 40. Health aspects • Creation of nuisance, unsightliness and pleasant odours. • Breeding of flies and mosquitoes • Pollution of soil and water supplies. • Contamination of food • Increased incidence of disease
  41. 41. Composition of sewage WATER 99.9% SOLIDS 0.1% SEWAGE
  42. 42. Aims of sewage purification • To stabilize the organic matter so that it can be disposed off safely. • To convert the sewage water into an effluent of an acceptable standard of purity which can be disposed off into land, rivers or sea.
  43. 43. Strength of sewage • Biochemical oxygen demand (BOD) • Chemical oxygen demand(COD) • Suspended solids
  44. 44. Biochemical oxygen demand (BOD) • It is defined as the amount of oxygen absorbed by a sample of sewage during a specified period, generally 5 days at a specified temperature generally 20 deg C for the aerobic destruction or use of organic matter by living organisms. • BOD value range from about 1mg per litre for natural waters to about 300mg/L for untreated domestic sewage. • If the BOD is 300mg /L and the above , sewage is said to be strong, if it is 100mg/L, it is said to be weak.
  45. 45. Chemical oxygen demand(COD) • The COD test measures the oxygen equivalent of that portion of the organic matter in a sample which is susceptible to oxidation by a strong chemical oxidizer.
  46. 46. Suspended solids • The amount of suspended solids in domestic sewage may vary from 100 to 500 ppm. • If the amount of suspended solids is 100mg/L, the sewage is said to be weak. • If the amount is 500mg/L the sewage is said to be strong.
  47. 47. Decomposition of organic matter Aerobic process Anaerobic process
  48. 48. Primary treatment • Screening • Removal of grit • Plain sedmentation Secondary treatment • Trickling of filters • Activated sludge process Other methods • Sea out fall • River outfall • Sewage farming • Oxidation ponds Sewered areas
  49. 49. MODERN SEWAGE TREATMENT Screen Grit Chamber Final Sedimentation Tank Biological Treatment Primary Sedimentation tank Sludge Digester Methane Gas Sludge drying beds Primary Treatment Secondary treatment Chlorine Effluent Disposal Sewage
  50. 50. Primarytreatment • Screening The screen consists of vertical or inclined steel bars usually set 5cm apart.
  51. 51. Primarytreatment Grit chamber • This chamber is approximately 10 to 20 m in length, • it is so designed as to maintain a constant velocity of about 1 foot per second with a detention period of 30 seconds to 1mt.
  52. 52. Primarytreatment Primary sedimentation • It is a very large tank holding from ¼ to 1/3 the dry weather flow. • Flow very slowly across the tank at a velocity of 1 to 2 feet per minute. • The sewage spends about 6 to 8 hours in the tank.
  53. 53. Secondary treatment Trickling filter method Activated sludge process
  54. 54. The trickling filter • The trickling filter or percolating filter is a bed of crushed stones or cinker, 1 to 2 m deep and 2 to 30 m in diameter depending on the size of the population.
  55. 55. Activated sludge process • The effluent is mixed with sludge drawn from the final settling tank. • The mixture is subjected to aeration chamber for about 6 to 8 hours. • The aeration is accomplished either by mechanical agitation or by forcing compressed air continuously from the bottom of the aeration tank. • Organic matter of the sewage gets oxidized into carbon dioxide, nitrates, and water with the help of aerobic bacteria.
  56. 56. Activated sludge process
  57. 57. Secondary sedimentation • Detained fro 2-3 hours. • The sludge that collects in the secondary sedimentation tank is called aerated sludge. • Part of the activated sludge is pumped back into the aeration tanks in the activated sludge process and the rest pumped into the sludge digestion tanks for treatment and disposal.
  58. 58. Sludge digestion • Digestion • Sea disposal • Land
  59. 59. Digestion • Incubated under favorable conditions of temperature and pH • Undergoes anaerobic auto digestion • Complex solids are broken down into water, carbon dioxide, methane and ammonia • The volume of sludge is also considerably reduced. • Dry readily and form an excellent manure. 3-4 weeks or longer
  60. 60. Disposal of effluent Disposal by dilution • Diluted in the body of water and impurities are oxidized by the dissolved oxygen in the water. • The Royal commission in England (1908) recommended that an effluent from a sewage treatment plant should not have more than 30mg/litre of suspended solids and the 5 day BOD of the effluent including the suspended matter should not exceed 20mg/litre. Disposal on land
  61. 61. OTHER METHODS Sea outfall River outfall Land treatment Oxidation pond Oxidation ditches
  62. 62. Sea outfall
  63. 63. River outfall
  64. 64. Land treatment (sewage farming)
  65. 65. Oxidation pond • Open shallow pool 1 to 1.5m depth with an inlet and outlet. • comprise algae, certain type of bacteria which feed in decaying organic matter and sunlight
  66. 66. Oxidation ditches
  67. 67. Role of Nurse • Survey • Health education • Construction of disposal units and supervision • Evaluation
  68. 68. Thank you

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