Sanitation

A brief presentation on sanitation and methods of sanitation

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 Bore hole latrine Dug well or pit latrine Water seal type Septic tank 3. LATRINES SUITABLE FOR CAMPS AND TEMPORARY USE Shallow trench Deep trench Pit Latrine Bore hole latrine

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

9. SEWERED AREAS Other methods, Sea outfall River outfall Sewage farming 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 : Excreta should not contaminate the ground or surface water Excreta should not pollute the soil Excreta should not be accessible to flies, rodents, animals (pigs, dogs, cattle, etc.) and other vehicles of transmission. 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.

20. 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.).

21. (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.

22. 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.

23. 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.

24. 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.

25. 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.

26. 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.

27. 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.

28. 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.

29. 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.

30. 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.

31. 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.

32. 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.

33. 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.