This document discusses sanitation methods for both unsewered and sewered areas. For unsewered areas, it describes latrine options like bore hole, dug well, and septic tanks. It notes the advantages and disadvantages of each method. For sewered areas, it explains the water carriage sewerage system and sewage treatment process, which includes primary treatments like screening and grit removal, as well as secondary treatments like trickling filters and activated sludge. The document provides detailed information on the design and functioning of various sanitation infrastructure components.

1. SANITATION
Dr. J. Aurlene
II year PG
Department of Public Health Dentistry

2.  “Sanitation is an arrangement for preventing human contact with the hazards of wastes and sewage
wastewater. It is a method of preparation for protecting and promoting health.”

3. PUBLIC HEALTH IMPORTANCE
• Sanitation system aim to protect human health by providing a clean environment
that will stop the transmission of disease, especially through the fecal-oral route.
• Human excreta is a source of infection and an important cause of environmental
pollution.
• HEALTH HAZARDS – typhoid, paratyphoid, dysentery, diarrhoea, cholera,
hookworm disease, ascariasis, viral hepatitis.
• ENVIRONMENT – soil pollution, water pollution, contamination of food,
propagation of flies and vectors.

4. Transmission of faecal diseases.
WATER
FINGERS
FAECES FOOD NEW HOST
FLIES
SOIL

5. SANITATION BARRIER
Disease cycle can be broken at various levels, segregation of faeces, protection of foods,
personal hygiene and control of flies. The most effective of which is segregation and proper
disposal of faeces.
WATER
FAECES FINGERS
FLIES
SOIL
FOOD

6. METHODS
UNSEWERED AREAS
SEWERED AREAS

7. UNSEWERED AREAS
1. SERVICE TYPE LATRINES – CONSERVANCY SYSTEM
2. NON-SERVICE TYPE – SANITARY LATRINES
a. Bore hole latrine
b. Dug well or pit latrine
c. Water seal type
d. Septic tank
3. LATRINES SUITABLE FOR CAMPS AND TEMPORARY USE
a. Shallow trench
b. Deep trench
c. Pit Latrine
d. Bore hole latrine

8. SEWERED AREAS
1. WATER-CARRIAGE SYSTEM AND SEWAGE TREATMENT
a. Primary treatment
b. Screening
c. Removal of grit
d. Plain sedimentation
SECONDARY TREATMENT
Trickling filters
Activated sludge process

9. SEWERED AREAS
Other methods,
a. Sea outfall
b. River outfall
c. Sewage farming
d. Oxidation ponds

10. UNSEWERED AREAS
SERVICE TYPE (CONSERVANCY SYSTEM)
The collection and removal of nightsoil from bucket or pail latrines by human agency is called the
service type or conservancy system, and the latrines are called service latrines.
The nightsoil is transported in "nightsoil carts" to the place of final disposal, where it is disposed
off by (i) composting or (ii) burial in shallow trenches.
DISADVANTAGES
They perpetuate the disease cycle of faecal-borne diseases in the community.
Water and soil pollution, exposed to flies.
Requires staff for collection of nightsoil

11. NON-SERVICE (SANITARY LATRINES)
A sanitary latrine is one which fulfils the following criteria :
(1) Excreta should not contaminate the ground or surface water
(2) Excreta should not pollute the soil
(3) Excreta should not be accessible to flies, rodents, animals (pigs, dogs, cattle, etc.) and other
vehicles of transmission.
(4) Excreta should not create a nuisance due to odour or unsightly appearance

12. BORE HOLE LATRINE
The bore hole latrine is the forerunner of the non-service type of latrines.
It was first introduced by the Rockefeller foundation during 1930' s in campaigns of
hookworm control.
The latrine consists of a circular hole 30 to 40 cm (12-16 in.) in diameter, dug vertically
into the ground to a depth of 4 to 8 m (13-26 ft.), most commonly 6 m (20 ft.). A special
equipment known as auger is required to dig a bore hole.
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. For a family of 5 or 6 people, a bore hole of
the above description serves well for over a year.

13. Advantages
a) there is no need for the services of a sweeper for daily removal of
nightsoil.
b) the pit is dark and unsuitable for fly breeding,
c) if located 15 m (50 ft.) away from a source of water supply, there should
be no danger of water pollution.
Disadvantages
a) the bore hole fills up rapidly because of its small capacity,
b) a special equipment, the auger, is required for its construction which may
not be readily available
c) 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 3 m (10 ft.).

14. DUG WELL LATRINE
Dug well latrine or pit latrine was first introduced in Singur, West Bengal in 1949-1950.
A circular pit about 75 cm (30 in.) in diameter and 3 to 3.5 m (10-12 ft.) deep is dug into the ground
for the reception of the nightsoil. In sandy soil, the depth of the pit may be reduced to 1.5 to 2 m (
6-7 ft.).

15.  Advantages
(1) it is easy to construct and no special equipment such as an auger is needed to
dig the pit
(2) the pit has a longer life than the bore hole because of greater cubic capacity.
A pit 75 cm (30 in.) diameter and 3 to 3.5 m (10-12 ft.) deep will last for about 5
years for a family of 4 to 5 persons.

16. WATER SEAL LATRINE
A further improvement in the designing of sanitary latrines for rural families is
the hand-flushed "water seal" type of latrine. Here, the squatting plate is fitted
with a water seal.
The water seal performs two important functions :
(1) it prevents access by flies. That is, the nightsoil is sealed off from flies, by a
small depth of water contained in a bent pipe called the trap
(2) it prevents escape of odours and foul gases and thereby eliminates the
nuisance from smell.

17. (1) the P.R.A.I. type, evolved by the Planning, Research and Action Institute,
Lucknow (Uttar Pradesh)
(2) the RCA type, designed by the Research-cum-Action Projects in
Environmental Sanitation of the Ministry of Health, Government of India.

18.  SHALLOW TRENCH
 This is simply a trench dug with ordinary tools. The trench is 30 cm (1 ft.)
wide and 90-150 cm (3-5 ft.) deep. Its length depends on the number of users
: 3-3.5 m (10-12 ft.) are necessary for 100 people.
 DEEP TRENCH
 This type of latrine is intended for camps of longer duration, from a few
weeks to a few months. The trench is 1.8 to 2.5 m (6-8 ft.) deep and 75-90
cm (30-35 in.) wide.

19. SEPTIC TANK
The septic tank is a water-tight masonry tank into which household sewage is admitted for
treatment.
It is a satisfactory means of disposing excreta and liquid wastes from individual dwellings, small
groups of houses and institutions which have adequate water supplies but do not have access to
a public sewerage system.

21. DESIGN
The main design features of a septic tank are as follows.
(1) Capacity : The capacity of a septic tank will depend upon the number of users. A capacity of
20-30 gallons or 21/ 2-5 c.ft. per person is recommended for household septic tanks. The
minimum capacity of a septic tank should be at least 500 gallons. Septic tanks are not
recommended for large communities.
(2) Length : The length is usually twice the breadth.
(3) Depth : The depth of a septic tank is 2 m (5-7 ft.).

22. (4) Liquid depth : The recommended liquid depth is only 1.2 m (4 ft.)
(5) Air space: There should be a minimum air space of 30 cm (12 in.) between the level of liquid in
the tank and the undersurface of the cover.
( 6) Bottom : In some septic tanks, the bottom is sloping towards the inlet end. This facilitates
retention of solids.
(7) Inlet and outlet : There is an inlet and outlet pipe, which are submerged.
(8) Cover : The septic tank is covered by a concrete slab of suitable thickness and provided with a
manhole.
(9) Retention Period : Septic tanks are designed in this country to allow a retention period of 24
hours.

23. ANAEROBIC DIGESTION - The solids settle down in the tank, to form"sludge", while the lighter solids including
grease and fat rise to the surface to form "scum". The solids are attacked by the anaerobic bacteria and fungi and
are broken down into simpler chemical compounds.
AEROBIC OXIDATION - The liquid which passes out of the outlet pipe from time to time is called the "effluent". It
contains numerous bacteriae, cysts, helminthic ova and organic matter in solution or fine suspension. The effluent
is allowed to percolate into the sub-soil.
Aerobic bacteria in the upper layers of the soil attack the organic matter present in the effluent. As a result, the
organic matter is oxidized into stable end products, i.e., nitrates, carbon dioxide and water.

24. SEWERED AREAS
The water carriage system or sewerage system implies collecting and
transporting of human excreta and waste water from residential, commercial
and industrial areas, by a net-work of underground pipes, called sewers to the
place of ultimate disposal.
It is the method of choice for collecting and transporting sewage from cities
and towns where population density is high.

25. • A water carriage system consists of the following elements.
• 1. Household sanitary fittings (plumbing system of buildings) - The usual
household sanitary fittings are : {i) water closet, wash basin.
• 2. House drain - The house drain is usually 10 cm (4 in.) in diameter and is laid in
the courtyard about 15 cm (6 in.) below the ground level on a bed of cement
concrete with sufficient gradient towards the . main drain.
• 3. Street sewers or trunk sewers - The trunk sewers are not less than 22.5 cm (9
in.) in diameter; bigger ones may be 2 to 3 m (8-10 ft.) in diameter. They are laid
on a bed of cement concrete, about 3 m (10 ft.) below the ground level
• 4. Sewer appurtenances: manholes, traps
MANHOLES are openings built into the sewerage system. These openings permit a
man to enter the sewer for inspection, repairs and cleaning.
TRAPS these are devices designed to prevent foul gases entering the houses and to
remove sand, grit and grease from sewage. Traps are placed in three situations : (a)
under the basin of water closets, (b) where the house drain joins the public drain
(intercepting trap), and (c) where surface waste water enters the drains.

27. MECHANISM
PRIMARY TREATMENT
SCREENING - Sewage arriving at a disposal work is first passed through a metal
screen which intercepts large floating objects such as pieces of wood, rags,
masses of garbage and dead animals. Their removal is necessary to prevent
clogging of the treatment plant.
GRIT CHAMBER - Sewage is then passed through a long narrow chamber
called the grit chamber or detritus chamber. This chamber is approximately 10
to 20 metres in length. The function of the grit chamber is to allow the
settlement of heavier solids such as sand and gravel, while permitting the
organic matter to pass through.

28. PRIMARY SEDIMENTATION - Sewage is now admitted into a huge tank
called the primary sedimentation tank. The sewage spends about 6-8
hours in the tank. Nearly 50-70 per cent of the solids settle down under
the influence of gravity. The organic matter which settles down is called
sludge and is removed by mechanically operated devices, without
disturbing the operation in the tank.

29. SECONDARY TREATMENT
The effluent from the primary sedimentation tank still contains a proportion of
organic matter in solution or colloidal state, and numerous living organisms.
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 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. Over the surface and down through the
filter, a very complex biological growth consisting of algae, fungi, protozoa and
bacteria of many kinds occurs. This is known as the "zoogleal layer". As the
effluent percolates through the filter bed, it gets oxidized by the bacterial flora in
the zoogleal layer.

31. ACTIVATED SLUDGE PROCESS
The effluent from the primary sedimentation tank is mixed with sludge
drawn from the final settling tank.
The proportion of activated sludge to the incoming effluent is of the
order of 20 to 30 per cent. The mixture is subjected to aeration in the
aeration chamber for about 6 to 8 hours.
During the process of aeration, the organic matter of the sewage gets
oxidized into carbon dioxide, nitrates and water with the help of the
aerobic bacteria in the activated sludge. The typhoid and cholera
organisms are definitely destroyed, and the coliforms greatly reduced.

32. SECONDARY SEDIMENTATION
The oxidized sewage from the trickling filter or aeration chamber is led
into the secondary sedimentation tank where it is detained for 2-3
hours.
The sludge that collects in the secondary sedimentation tank is called
'aerated sludge' or activated sludge, because it is fully aerated.
It differs from the sludge in the primary sedimentation tank in that it is
practically inoffensive and is rich in bacteriae, nitrogen and phosphates.
It is a valuable manure, if dehydrated.

33. OTHER METHODS
• SEA OUTFALL
Sea coast towns and cities may dispose of their sewage by discharging it into
the sea. Nearly two-thirds of untreated sewage of Greater Mumbai is
discharged every day into the Arabian Sea. Purification takes place by
dilution in the large body of sea water, and the solids get slowly oxidized. The
drawback of this method is that the offensive solid matter may be washed
back to the shore and create public nuisance.
RIVER OUTFALL
Raw sewage should never be discharged into rivers.
The present day practice is to purify the sewage before
it is discharged into rivers.

34. LAND TREATMENT
If sufficient and suitable land (porous soil) is available, sewage may be
applied to the land after grit removal, screening and a short period of
settlement. This type of treatment is practised in some Indian towns and
cities and is known as Sewage Farming or Broad Irrigation. An acre of land
would be required to treat the sewage of 100-300 persons.
OXIDATION POND
The oxidation pond is an open, shallow pool 1 to 1.5 m (3-5 ft.) deep with an
inlet and outlet
To qualify as an oxidation pond, there must be the presence of (1) algae (2)
certain types of bacteria which feed on decaying organic matter, and (3) sun-
light. The organic matter contained in the sewage is oxidized by bacteria
(hence oxidation pond) to simple chemical compounds such as carbon
dioxide, ammonia and water.

35. SWACHH BHARAT MISSION
• To accelerate the efforts to achieve universal sanitation coverage and
to put focus on sanitation, the Prime Minister of India launched the
Swachh Bharat Mission on 2nd October, 2014. The Mission
Coordinator for SBM is Secretary, Ministry of Drinking Water and
Sanitation (MDWS) with two Sub-Missions, the Swachh Bharat
Mission (Gramin) and the Swachh Bharat Mission (Urban). Together,
they aim to achieve Swachh Bharat by 2019, as a fitting tribute to
Mahatma Gandhi on his 150th Birth Anniversary.
• In Rural India, this would mean improving the levels of cleanliness
through Solid and Liquid Waste Management activities and making
villages Open Defecation Free (ODF), clean and sanitised.

36. Achievements
• 6,21,40,813 household toilets constructed.
• 3,21,321 open defecation free villages.
• 314 open defecation free districts.
• 11 open defecation free states.