DABTU Wastewater Treatment T E (CIVIL)

1. Online Lecture- 21
Rural Sanitation
Module VI
WasteWater Treatments

2. Contents
• Rural areas, Population habits and environmental conditions,
problems of water supply and sanitation aspects, low cost excreta
disposal systems, Rural sanitation improvement schemes

5. Introduction
• We live in a time of rapid change and progress in science and
technology with changes in housing structures, lifestyle, food habits,
clothing, education, but one of the major challenges that still remains
is tackling the problem of open defecation.
• Open defecation has been practiced since the beginning of time by all
creatures. Individuals use agricultural fields, wastelands, banks of
lakes/rivers, forestlands and open waste places to defecate.
• Defecation sites are usually far from human settlements. Over the
years due the influence of factors like modernisation, changed cultural
behaviour, changes in social life and education, have developed
technologies for sanitation ranging from using dry toilets to flush
toilets and ecological sanitation.

7. • Dry Latrines :- Dry toilets are different from water sealed toilets. In
this type of a toilet, a seat with a hole is directly connected to a pit. In
some communities buckets were used for collecting faeces and were
cleaned by persons belonging to lower castes.
• Flush toilets/ Water sealed latrines:- Legislations such as prohibition
on manual scavenging and construction of dry latrine gave space for
the use of a new technology called flush toilet or water sealed
latrines; where-in a connection from the water sealed toilet pan to
“Under Ground Drainage (UGD)” and septic tanks came into
existence.
• Ecological Sanitation: - Ecological sanitation technology incorporates
the principles of recycling faeces, urine and wastewater which are
collected separately, treated and used as compost and fertilizer for
agricultural crops.

8. Concept of Rural Sanitation:
• The concept of sanitation broadly includes liquid and solid
waste disposal, personal and food related hygiene and
domestic as well as environmental hygiene.
• It would not be wrong to say that it hardly describes the
sanitary conditions as they obtain in the villages of India.

9. • Central Rural Sanitation Programme:
• Rural Sanitation PrCentralogramme (CRSP), a centrally sponsored Rural
Sanitation Programme was launched in 1986. Its objective is to improve
the quality of life of the rural people and provide privacy and dignity to
women.
• It was designated to provide sanitary latrines to the SCs/STs, landless
labourers and people living below poverty line and the resources were
shared by the central and state governments on 50: 50 basis.
• The programme was planned with the objective of providing clean,
healthy and environmentally acceptable disposal of excreta with a view
to create good sanitation and consequent improved health standards.
• The CRSP is implemented in different states and union territories for
improving sanitation facilities through construction of sanitary latrines for
individual households.

10. • Total Sanitation Campaign (TSC):
• Total Sanitation Campaign (TSC) was initiated on 1st April 1999 under
sector reform process. The campaign is community led and people
centred. It was launched after restructuring Central Rural Sanitation
Programme and is operational in 451 districts with an out IAY of Rs.
4,416 crores in which community contribution is Rs. 812 crore.
• Catchment Area Approach (CAA) has been adopted for monitoring
and surveillance by involving various grass roots level educational and
technical institutions by utilizing existing resources and strengthening
them by providing additional financial resources.
• The components of the TSC are:
✓I. Construction of household latrines.
✓II. Construction of sanitary complex for women.
✓III. Toilets for schools.
✓IV. Toilets for Balwadi/Anganwadi etc.

11. • The main features of the TSC are as under:
1. Shift from high subsidy to low subsidy regime.
2. Greater household involvement and PRI participation.
3. Technology options as per choice of beneficiary households.
4. Stress on Information, Education and Communication (lEC) as part of
the campaign.
5. Emphasis on school sanitation, women sanitary complexes.
6. Integrating with various rural development programmes.
7. Involvement of NGOs and local groups.
8. Promoting access to institutional finance and social marketing
concept.

12. “Nirmal Gram Puraskar” (NGP):
• It is an incentive scheme instituted in October 2003 under the TSC in
recognition of the role played by Panchayati Raj Institutions,
organisations and individuals in promotion of rural sanitation.
• As per this scheme, awards are given to Panchayati Raj Institutions
at various levels which attain full sanitation coverage in households,
schools, Anganwadis with general cleanliness and become open
defecation free.

16. DISPOSAL OFEXCRETA

17. Health hazards of improper
excreta disposal
• Soil pollution
• Water pollution
• Contamination of foods
• Propagation of flies

18. Spread of disease from excreta

19. Sanitation barrier

21. Methods of excreta
disposal
Unsewered areas
• Service type latrines( conservancy system)
• Non service type( sanitary latrines)
• Latrines suitable for camps and temporary use.

22. Non service type( sanitary
latrines)
• Bore hole latrine
• Dug well latrine
• Water seal latrine
❖PRAI type
❖RCAtype
❖Sulab shauchalaya
• Septic tank
• Aqua privy

23. Latrines suitable for camps and
temporary use.
Shallow
trench
latrine
Deep
trench
latrine
Pit
latrine
Bore
hole
latrine

24. 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

25. 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

26. 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

27. 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

28. Bore hole latrine
30-40 cm diameter
4 to 8 m depth

29. 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.

30. 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.

31. Dugwell latrine
• 75 cm diameter
3 to 3.5 m deep

32. 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.

33. Ventilated Improved Pit (VIP)Latrine
Figure 6.7. Ventilated improved pit latrine
6

34. Poor flush Latrines
Pour-flush latrines may be constructed directly above a pit or may be offset, whereby the
Figure 6.9. Pour-flush latrines

35. • Pour-flush latrines rely on water to act as a hygienic seal and to help
remove excreta to a wet or dry disposal system.
• The most simple pour-flush latrines use a latrine pan incorporating a
shallow U-bend which retains the water (Figure).
• After defecation, a few liters of water must be poured, or thrown,
into the bowl in order to flush the excreta into the pit or sewerage
system below
6
Figure 6.8. Cross-section of typical water-seal pan

36. 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.

37. Essential Features of RCAlatrine
Location
Squatting
plate
Pan
Trap
Connecting
pipe
Dug well
Superstructure Maintenance

38. RCAlatrine
• Location
15m

39. 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

40. Pan and Trap
42.5cm

41. 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.

42. • 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.

43. • 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.

45. SEPTIC
TANK

46. Septic tanks

47. 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.

48. 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

49. •
• 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

50. Aqua Privy

51. 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

52. 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.

53. LATRINES SUITABLE FOR TEMPORARY USEAND
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.

54. Shallow trench Latrine

55. The trench is 1.8 to 2.5 m deep and 75-90cm wide.

56. ECOSAN TOILET

57. • The toilet is designed in such a way that the Urine is seperated from
the faeces.
• Further the water used for washing of hands as well as the toilet is
separated out and sent to natural filter beds, from where it irrigates a
field nearby.
• The urine is taken by a separate pipe and stored in a vessel to be used
as fertiliser.
• The faecus is kept dry by adding ash and lime, so the time taken to
destroy the pathogens is shorter.
• When the first chamber is full it is sealed up, and the time taken for
the next chambers to get filled up is sufficient for the excreta to
degrade so that it can be handled safely, without odour, and is ready
to use as manure.

58. Benefits of ECOSAN toilets
✓Prevent ground water contamination as the chambers are kept
above ground and full sealed. Ideal for users in waterlogged,
high ground water table areas.
✓The unit does not require any type of flushing mechanism,
eliminating the risk of mechanical failure. Does not require de-
sludging or pumping out black water
✓It has no sewer connections. Saves water as it does not
require any water to carry human waste; no plumbing is
required.
✓Does not require any treatment of urine or faeces.
✓No flies or foul smell. No mosquito breeding as there is no
water stagnation.

61. MCQs
1. In ________ _________ type of a toilet, a seat with a hole is directly connected to a
pit.
2. __________ ___________ technology incorporates the principles of recycling
faeces, urine and wastewater which are collected separately, treated and used as
compost and fertilizer for agricultural crops.
3. The concept of ____________broadly includes liquid and solid waste disposal,
personal and food related hygiene and domestic as well as environmental
hygiene.
4. 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.
5. __________latrine is a circular pit about 75 cm in diameter and 3 to 3.5 m deep.
6. Latrine shall at least ___m away from water source.
7. _____________ type od toilets Does not require any treatment of urine or faeces.