solid waste disposal excreta disposal

1. Excreta disposal

2. Public Health Importance
Human excreta is a source of infection
Important cause of environment pollution
Responsibility of society to dispose it safely
Failure to dispose safely leads to severe threat to public health

3. Health hazards
Improper excreta disposal causes
Soil pollution
Water pollution
Contamination of foods
Propagation of flies
Burden to community in terms of sickness, mortality & low
expectation of life
Deterrent to social & economic progress

4. Diseases-improper disposal
Bacterial: typhoid, dysenteries
Viral: hepatitis, diarrhoeas
Helminths: hook worm, ascariasis

5. Extent of problem-India
74% of population is rural and majority of them go to fields for
defecation
Situation in urban area is equally worse
The solution to the problem is only through hygienic disposal of
human excreta which is a corner stone of all public health services

6. HOW THE DISEASE IS CARRIED FROM EXCRETA
FAECES
FINGERS
FLUID/WATER
FLIES
FIELD/SOIL
FOOD NEW HOST

7. Transmission of diseases to the human host is prevented by
segregation of faeces, protection of food, personal hygiene,
control of flies.
Transmission of faecal born diseases

8. FAECES
FINGERS
WATER
FLIES
SOIL
FOOD
PROTECTED HOST
S
A
N
I
T
A
T
I
O
N
B
A
R
R
I
E
R
Sanitation barrier –
Transmission of faecal-borne diseases

9. SANITATION BARRIER
Segregation of excreta by imposing a barrier is called Sanitation
barrier. This is the most effective step so that the disease agent
can not reach the new host directly or indirectly

10. METHODS OF EXCRETA DISPOSAL
Unsewered Areas Sewered Areas

11. Unsewered Areas
I) Service type (conservative)
II) Non service type (sanitary latrine)
1. Bore hole latrine
2. Dug well or pit latrine
3. Water-seal type of latrines
a) PRAI
b) RCA
c) SULABH
4. Septic tank
5. Aqua privy
III) Latrine suitable for camps & temporary use
• Shallow trench/deep trench/pit/bore hole latrines

12. I) SERVICE TYPE
Night soil is collected from pail or bucket type of latrines by
human agency, and later disposed by burying or
composting.

13. DRAWBACKS
Water pollution
Soil pollution
Access to flies
Corrosion of buckets and pans
Recruitment of staff is difficult (UNETHICAL), should be replaced
by sanitary latrine

14. II) Non- Service type/ Sanitary latrines
Criteria-
Excreta should not contaminate the ground or surface water
Excreta should not pollute the soil
Excreta should not be accessible to flies, rodents, animals & other
vehicles of transmission
Excreta should not create a nuisance due to odour or unsightly
appearance

15. 1.Borehole latrine
Forerunner of the non-service type of latrine
First introduced by Rockefeller foundation during 1930’s in campaigns of
hookworm control
It consists of a circular hole of 30 to 40 cm diameter and 4 to 8 m depth
Special equipment Auger is used

17. Contd.
The hole is lined with bamboo matting or earthen ware rings to prevent
caving of soil.
A concrete squatting plate with a central opening and foot rests paced
over the hole and an enclosure for privacy
It serves for a family per year
Night soil under goes anaerobic digestion.

18. Contd.
MERITS
No need for sweeper for daily removal.
DEMERITS
Small capacity
Auger may not be available
If the soil is loose it becomes difficult to dig

19. 2.DUGWELL LATRINE/ PIT LATRINE
Introduced first in Singur in West Bengal in 1949-50
It is an improved Bore hole latrine
It is a circular pit of 75 cm diameter and 3 to 3.5
depth lined by pottery rings.
A squatting plate at the top with a super structure

21. Contd.
MERITS
No need of auger
Greater capacity
Last for 5 years per family

22. 3. WATER SEAL LATRINES
It has water seal which prevent access to flies
and escape of odour.
Modifications of water seal latrines
P.R.A.I
a) evolved by planning research and action institute Lucknow.
b) R.C.A. type by research cum action projects in environmental sanitation
of ministry of health.
Direct type
Indirect
Type

23. of
LOCATION: It should be away from source of water supply to prevent contamination.
SQUATTING PLATE or SLAB: It is made up of an impervious material to keep it clean
and dry. So that it will not facilitate the
growth of hook warm larva.
Dimensions 90 cms square,
5cms thickness, slop ½ inch for drainage
water with footrests.
RCA Latrine (more popular)

24. Pan: Receives the night soil, urine and wash water. The length of pan is
42.5cm. The width of the front portion of the pan has a minimum of 12.5cm
and the width at widest portion is 20cm. There is a uniform slope from front
to back of the pan and the pan is given a smooth finish

25. Trap: the trap is a 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 provides the access by flies and suppresses the nuisance
from smell
2cm

26. Connecting pipe: when the pit is dug, away from the squat plate, the trap is
connected to the pit by a short length of connecting pipe 7.5cm in diameter
and at least 1m in length with a bend at the end
it is used in indirect type and the advantage with this is that when the pit fills
up, a second pit can be put into operation

27. 1
2
3
4
5
Indirect Type

28. Dug well: 75 cm in diameter, 3-3.5m deep
Superstructure: Attractive superstructure
Maintenance: Proper maintenance involves health education of the
people which is very necessary for the success of any sanitation related
programme

29. Comparison of Direct and Indirect type Water Seal Latrines
Direct type Indirect type
• Pit is below the squatting plate
• Best for areas with hard ground
• Cheaper
• Easy construction
• Occupies less space
• Pit is away from the squatting plate
• When the pit is full, direction of
connecting pipe can be changed to
another pit
• Preferred over direct type

30. c) Sulabh Shauchalya
Low cost water-seal type latrine by Patna based firm. 5Rs/use charged

31. It is a water tight masonry tank used for individual dwelling, small
groups of houses and institutions.
DESIGN: Single chambered or double chambered.
CAPACITY: 20 to 30 gallons per person for household with a
minimum of 500 gallons.
4.SEPTIC TANK

32. LENGTH: Twice the breadth.
DEPTH: 1.5 to 2 meters.
LIQUID DEPTH: 1.2 meters.
AIR SPACE: 30cms It is the level between
liquid and undersurface of cover.
BOTTOM: Sloping towards inlet end for
retentions of solids.
INLET AND OUTLET:
COVER: Concrete slab with a manhole.
RETENSION PERIOD: 24hrs if it is too small
inadequate treatment too long undue septicity occurs

33. • WORKING: That is purification of sewage by 2 stages
Anaerobic digestion in septic tank proper
Aerobic oxidation out side the septic tank in the sub soil
Sludge and scum  anaerobic digestion  effluent  aerobic oxidation
Septic tank-contd.

34. MAINTAINANCE: Disinfectants should be avoided as they are
injurious to bacterial flora of tank.
De sludging should be done as excessive accumulation interfere
with proper working
Newly built tanks first fill with water up to the outlet then with sludge
to provide right type of bacteria to carry out decomposition process.
Septic tank-contd.

35. 5.Aqua Privy
• Similar to septic tank
• For a family per 6 years

36. III) Latrines suitable for temporary use/ camps
1. Shallow trench latrine
2. Deep trench latrine
3. Pit latrine
4. Borehole latrine

37. Trench Latrines
Dug up Earth
piled up on
the side for
covering

38. Trench Latrines
Shallow trench latrine Deep trench latrine
• 30 cm wide
• 90-150 cm deep
• Serves for a week
• 75-90cm wide
• 1.8 – 2.5cm deep
• Serves for weeks to months

39. Next class-Sewered areas and sewage t/t