RURAL SANITATION

WASTE WATER DISPOSAL SYSTEM FOR RURAL AREAS Introduction A large section of Indian population lives in villages and is mainly engaged in agriculture. They belong to weaker section of the society. There is a definite trend of rural population migrating to the urban areas due to lack of employment opportunities, low earnings, insufficient means of transport and insanitary living conditions. The latter is mainly responsible to repel the educated youth from working in rural areas. One source of insanitary condition in rural areas is the drainage of waste water from bathing and cooking areas of dwellings over the kutcha roads and lanes having inadequate slopes. The situation is further aggravated due to the movements of carts and animals which result in the creation of pot holes and ditches that gets filled up with dirty stagnant water. The mosquitoes and flies find good breeding centres in these places and spread diseases.

Some of the village roads are brick paved with drains for waste water disposal. But these have not served the required purpose due to improper slopes, insufficient maintenance and unpredictable flow of water. Rural dwellings having their own source of water supply like hand pumps discharge more water on the streets. Furthermore, the agricultural waste and domestic refuse collect in drains obstructing the flow of water and ultimately, all these things appear on the streets. Some of the village panchayats* have suggested individual pits for collection of waste water and its disposal by intermittent sprinkling on large areas, either in the courtyard or on the streets. The villagers adopt this practice for some time, but their enthusiasm dies with time. A few progressive farmers have access to the technical know-how and capacity to invest finance to make large sized soakage pits filled with brickbats (to dispose off water underground). These are frequently choked with ash and soil used by the villagers to clean their utensils. This requires cleaning of the pit and involves considerable expenditure. The high cost of construction and costly maintenance make it beyond the reach of the poor.

A detailed study of the problem, including the living habits of rural population, was conducted by the Central Building Research Institute, Roorkee. The urban type of underground drainage system was not found suitable because of the settlement of silt and ash in drains; insufficient quantity of water for self-cleaning of the drains; high maintenance and running cost. The lack of interest in the maintenance of community services leads one to conclude that the proposed system should be such that it should make the individuals responsible to run their own waste water disposal system. At the same time, the system should be within the economic reach of a villager who can maintain it without outside help. Keeping in view all these factors, a system has been developed at this Institute to dispose off waste water in rural areas. Salient features of this system are given below:

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A prototype of the proposed soakage system was built in the colony of poor people in a village near Roorkee about thirty years' ago. After its satisfactory performance four such soakage systems were provided in four different houses in another village and now thousands are functioning without any problem. Construction Procedure A pit equal to the outer dimensions (60 x 100 x 66 cm) of the chamber is excavated. A layer of flat bricks in mud mortar is laid at the bottom of the pit to form floor of the chamber. The walls 7.5 cm thick in burnt bricks with 1:6 cement sand mortar are built as per the design (Figure 2). This chamber is divided into two compartments by a wall of 7.5 cm thick. The sizes of the first and the second compartment are made as 45 x 45 x 70 cm and 30 x 45 x 70 cm respectively. A triangular duct 8 x 8 x 46 cm is made diagonally opposite to the inlet of the first compartment. A similar duct is made adjacent to the first duct in the second compartment. A hole is left in partition wall 19.0 cm below the top of the duct portion to provide connection between the two ducts. All the walls of the chamber are made 11.5 cm above ground level. Two precast R.C.C. (1 :2:4) covers of 5 cm thickness and 56 x 60 cm and 41 x 60 cm size respectively are made to cover ash/silt trap chamber. The second compartment is filled with 4 cm size brick ballast. Bore hole 30 cm in dia. is made with the help of an auger at a minimum distance of 30 cm from the chamber. It is taken up to the first layer of sand or up to 3 m. depths whichever is less. The bore hole should be made at least 6 m away from the hand- pump or well. A drain covered with brick is made 51 cm above floor level of chamber to connect bore hole with chamber. Brickwork 11.5 cm thick 30 cm deep is carried out around the circular hole to protect the top from collapsing. The bore hole is also filled with 4 cm size brick ballast. The top of the bore hole is covered by laying flat brick plastered with 1:6 cement-sand mortars or with 5 cm thick R.C.C. cover. Observations Observations were made about the working of this proposed system on the prototype constructed about thirty years ago in the villages near Roorkee. They were found satisfactory for a period of four months and, after that, water started overflowing. On .inspection it was found that the first compartment of ash/silt trap chamber was filled with ash, choking the lower mouth of the connecting duct. It was cleaned by the owner of the house and put back into service. Further observations lead to conclude that, in spite of the introduction of the ash/silt trap chamber, some suspended material and ash may flow into the bore hole before the complete closure of the duct. Therefore, it is recommended that even if the back- flow of water due t" closing of the duct does not take place, the first compartment of ash/silt trap chamber should be cleaned once in four months and the brick aggregate of the second compartment at least once in eight months to avoid chance of such flow and failure of the hole. Conclusions The proposed soakage system is a small compact unit designed for individual dwelling. This simple technique involves the use of locally available materials and labour. The technique is compatible to the average villager's economic level. This whole system is covered and is below the ground level enabling free traffic movement above it. Chances of mosquito breeding are completely eliminated. Pollution of rivers and ponds are avoided in this system. Only an auger for making the bore hole is required and this could be procured by village panchayats or social welfare organizations. The simplicity of construction and low cost, it is hoped, should encourage villagers to adopt this system, thereby improving the environmental conditions of the village as a whole.

The plus point of this system is recharging of ground water. This system can also be constructed using ferro cement technology by maintaining internal dimensions of the system.

Low Cost Sanitation

Introduction Poor health in developing countries is largely due to diseases like cholera, dysentery, gastroenteritis and worm infections carried by contaminated food water and ground. Effective sanitation is an important way of reducing the incidence of such diseases but modern water borne sanitation system is not possible in many parts of the world, due to its high cost and shortage of water. High cost of providing sewers for rural as well as urban areas having low density makes them non-acceptable due to financial constraints. Therefore, it is important to search for appropriate alternatives. In India a large number of people have no latrines or have bucket or dry latrines, especially in rural areas condition is worse in comparison to these national average and majority of people resort to open air defecation. Statistics reveal that 120 million people in the world are without adequate water supply and 1350 million without sanitary facilities in rural areas is 15 percent. Bore- hole latrines with precast slabs had been tried in India but these suffered from the nuisance of odour and fly breeding. The pits get filled up soon necessitating a change of site. The design was improved with addition of concrete pan and water seal trap to cut odour and flies. A number of efforts have been made since 1930, to further improve the design, as a result of which more than a dozen designs of sanitary latrines have been developed varying from the simplest design of bore-hole type to the complex design of Electrolux Vacuum System. Their applicability and acceptance depend on the preferences based on availability of space, local soil conditions and finance. Each of them has potentiality of its adoption under different circumstances. However, a design for wider application should be simple, inexpensive in construction and should provide freedom from odour, unsightly conditions, handling of fresh excreta and its contacts with flies and animals. It should eliminate chances of contamination of surface soil, and ground water that may enter springs or wells. In addition to these basic criteria the following requirements have to be considered while proposing any excreta disposal system for developing countries: • Daily operation should require minimum education and guidance to users of all ages. • Cost of the system should be within the reach of users. • Construction of the system should be based mainly on the use of local materials and its

maintenances should be possible with semi-skilled labour, available in the areas. • Requirement of water for transport and treatment should be minimum.

• The system should include the possibility of improvement in future when economic condition of the users improves.

CBRI’s contribution This institute has studied different types of designs available for construction of low cost rural and urban latrines to suggest economically viable and acceptable solutions for developing countries. Different aspects like size of the super structure, type of latrine pans and water seal, different specifications for construction of leaching pits including their distance from one another and from existing buildings have been examined. Following recommendations are made on the basis of these studies:- 1. Type of Latrine Hand-flushed water seal latrine seat proposed by Planning Research and Action Institute (PRAI), Lucknow and National Environmental Engineering Research Institute (NEERI), Nagpur and as already adoption by Indian standards institution (ISI), New Delhi is recommended for adoption due to its low water requirements for flushing and low cost. The design consists of cement concrete/mosaic pain, known in the market as PRAI type seat, (now available in sanitary were as well as in F.R.P), P-shaped trap having 20mm water seal, foot rest, and two pipes made of cement concrete or any other suitable material (covered channel made of brick can also be used) and connected with two leaching pits. The pipes of bricks channels are connected with seat through a connecting chamber which permits ease in shifting the connection to the second leaching pit when the first gets filled up after the stipulated period of 5years.The first pit can be emptied for successive use after a further lapse of 3 to 5 years and the contents, use as manure. 2. Size of Latrine Size of 75cm x 90cm is the minimum but it needs strict supervision and control of dimensions while fixing the pan and foot rest to maintain proper clearances. Fat and tall people feel it a bit congested. The size of 80cm x 100cm is more appropriate and optimum to satisfy all the persons. Therefore, 80cm x 103cm size is adopted in the enclosed drawings after considering the size of the brick available in the market. 3. Materials and Construction Nine different specifications for the construction of latrine, sixteen for lining the leaching pits and four for pits covers were finalized alter considering the material and skill available in different part of the country. The materials used include brick concrete, ferro-cement, used bitumen drum, bamboo mats and earthen rings. Typical designs using brick (due to their availability in most of areas) with brief specifications are shown in Figure. 1(a), 1(b) and Figure. 2. However, drawings proposing use of other materials can be made available. 4. Infiltrative Capacity of Soil It has been observed that the infiltrative capacity rate of percolation of water decreases after first use of the leaching pit due to deposition of organic matter in between the soil particles. This

can be improved by keeping the pit open to sky for one month after removing the decomposed excreta during dry weather or scrubbing the wall surfaces and digging the bottom of pit to remove part of the soil. Studies have also been carried out on water percolation in leaching pits with honey comb brick wall and with solid brick wall without plaster of pointing; with impervious floor and without floor. Effect of walls with or without honey comb brick work was found to be insignificant but that of floors was very high. It is, therefore recommended that the walls of leaching pit should be solid but without plastering or pointing to make them structurally strong and to avoid caving of soil. The floor should however, be without any lining except in high subsoil water table areas where it has to be impervious to reduce change of pollution. Distance between Leaching Pits A minimum distance of one meter is recommended between two leaching pits to avoid seepage of water from one to the other. However, it has been observed that making two leaching pits together with a common wall is easier to construct. 6. Distance of Leaching Pits from Existing Buildings When the depth of leaching pit goes 100 cm below the foundation of buildings, the minimum distance of a leaching pit from existing structure can be 85 cm for clayey sand and 125 cm for sandy clays. This distance can be adjusted proportionately when the depth of leaching pit below the foundation varies. 7. Volume of Leaching Pits The volume of leaching pit has been based on the average value of 44lit.per person per year and a pit of 1.1cubic meter capacity will therefore; serve five users for about 4year in sandy soil and 6years in clayey soils. 8. Optimization of Leaching Pit Two basic shapes i.e., square and circular were studied for structural stability and ease in construction. It has been found that the size of leaching pit being small, there is no significant difference in the structural properties of the two. However, construction of a circular pit needs skilled labour and proper care while the square one is easy to construct for most of the masons. Other parameters like structural safety of the pit and its cover, handling of the covers by the labour, absorption characteristics of the soil, working space required by labour during construction and removal of decomposed excreta and minimum cost of the leaching pit, when considered together, lead to the conclusion that optimum diameter and depth for circular pit should be 1.07m and 1.22m respectively for five users for five years. Similarly width and depth for square pits should be 0.92m and 1.2m respectively. Pollution Aspect in High Subsoil Water Level Areas Water discharge along with the excreta gets absorbed underground and has potential danger of mixing up with subsoil water and thus carrying contamination for long distances. Safe distance to avoid these chances has been recommended as 2m between the bottom of the pit and

subsoil water table but it is not always possible to maintain this. In many places the subsoil water table is so high as to cause direct mixing of the water discharge with excreta, with it. There is a need to avoid such mixing and therefore the design is not suitable for such locations. It is proposed to make the bottom of the pit impervious by using polythene sheet and filling 45cm thick layer of fine sand around the pit to act as filter to reduce the chances of pollution. This institute has also developed a low cost alternative to solve the problem to excreta disposal for areas with very high subsoil water level. It consists of a decomposition tank and two leaching pits. The night soil is allowed to pass to the leaching pits after it has completely decomposed. The details of the system can be supplied on demand.

Field Experiments The latrines described above have been constructed in Roorkee town and Mewad Kalan, Khanjarpur and other villages for individual owners and by Sulabh international, Patna for making feed back studies. Following observation have been made:- • Owners, masons and labours preferred two square pits built together, with solid partition wall against

two circular pits due to ease in construction, in digging of pits and less space required to accommodate them.

• 11.5cm (4 ½”) thick wall for lining the leaching pit behaves better than 7.5cm(3")thick wall due to ease in laying and better stability against concentrated lateral loads.

• Solid R.C.C pit cover, 7.5 cm thick with sufficient reinforcement should be provided to avoid any accident due to unexpectedly high loads or point load caused by cattle.

• All latrines are working satisfactorily and their demand has increased manifold. Cost The cost of latrine up to plinth level and with superstructure has been estimated as Rs. 4550 and Rs. 7600 respectively at Roorkee market rates in Jan 2004. Details of material and labour requirements are given in Appendices A and B. Conclusion Satisfactory performance of the low-cost sanitary latrines built at various places has paved the way towards a solution of the problem Low initial expenditure and maintenance cost makes them more acceptable even to the weaker section of society.

Figure 2: Twin Leaching Pit for Latrine

Appendix A

Materials & Labours requirement for construction Of low cost latrine up to Plinth Level Only Materials 1. Cement 4-5 bags 2. Sand 0.60 m3 3. 1st class brick 750 nos 4. Stone Aggregate 0,2 m3 12 mm & down gauge 5. Brick Aggregate 40 mm size 0.12 m3 6. M.S. bar 6 mm dia 10.50 kg 7. W.C Seat with trap one set 8. Foot rests one pair 9. Binding Wire 200 gms Labours (man days) Skilled 04 Unskilled 08

Appendix B

Materials & Labours requirement for construction Of low cost latrine: Complete Materials 1. Cement 6-7 bags 2. Sand 1.0 m3 3. 1st class brick 1180 nos 4. Stone Aggregate 0.3 m3 12 mm & down gauge 5. Brick Aggregate 40 mm size 0.12 m3 6. M.S. bar 6 mm dia 13 kg 7. Door shutter complete including 1 no.

painting 8. W.C Seat with trap one set 9. Foot rests one pair 10. Binding Wire 200 gms Labours (man days) Skilled 08 Unskilled 14