Proper disposal of human waste is an important part of environmental sanitation, since the intestinal infections, so common to man, are transmitted by faecal discharge of sick persons through carriers of disease such as flies, drinking water, contaminated food sold on the roadside, etc.
To control the spread of such diseases it is only necessary to provide a barrier between the source of infection (the excreta) and the susceptible host (the human being) by preventing faecal matter from coming into direct contact with men or with their food or with their drinking water.
A sanitary latrine of the pour-flush type and a disposal pit are not expensive but are effective in controlling faecal borne diseases and are easy to build in rural areas. Every rural household should have one such latrine, since the cost of building it is far less than the cost of medial care otherwise necessary; and there will be less loss of man power and human life due to faecal borne disease (NBO, 1989).
Essential Parts
The essential parts of a sanitary latrine as are (Figure 3.3) :
- Pan,
- Trap,
- Lead-off Pipe,
- Plate or Slab with Foot-rest, and
- Pit.
The trap can be 70 to 75 mm in diameter. However, upper opening of the trap which is connected to the pan should be 75 mm. Experience has shown that a trap having 75 mm diameter gives a high velocity flush with large masses of faecal matter. The recommended depth of water seal is 20 mm.
 |
| Rural Sanitary Latrines |
The lead off pipe is to be used when the squatting plate is set off from the pit. It should be 75 mm in diameter.
The pit is of 750 mm diameter or 750 mm square and 2000 mm or 3000 mm depth. This pit will eventually fill up and should be closed with earth and a new pit is to be used (Figure 3.3). If a filled pit is covered with earth and left, the faecal matter matures in a year or so and can be utilised as a fertilizer. While the first filled pit is maturing,,a second pit is dug and the lead off pipe should be switched to drain into the second pit. The minimum distance between the two pits should be 100 cm clear. In loose soil, brick-work lining is essential for the pit.
 |
| Arrangements of Pits |
The slab or squatting plate is of cement concrete with the minimum dimension of 900 mm square, but it can be larger. It is 50 mm thick at the outer edge. There is a 12 mm slope towards the pan so that the slab is 38 mm thick at the pan opening in the centre. The slope is necessary to drain off all water from the plate into the Pan.
The overall length of the footrest is 350 mm and its back edge extends to 75 mm beyond the outer rim of the pan, at its widest diameter. The inner edge of the footrest continues forward along the rim of the pan and then angles off for a distance of 130 mm. The front edge is 145 mm wide and forms a right angle with the outer edge of the footrest. The minimum height of the footrest is 12 mm. The back portion is raised slightly (12 mm) as to give a slope which makes for a more comfortable squatting position.
Superstructure
The specifications of a structure vary according to the means of the family. An ordinary structure can be constructed with bamboo posts at four comers and with bamboo matting as walling, with a bamboo matting door in the front. The floor of the latrine should be such that it can be washed and kept clean. The clear height of the roof should be, at least 2 m. A more permanent brick construction is, however, always preferable.
Construction
The pan, the trap, the squat-plate and the lead-off pipe can be manufactured at a central place from where they may be supplied to a number of villages. A number of State Governments give subsidies to defray the cost of pan, trap and squatting plate.
Latrine Location
There is a minimum safe distance between the latrine and a source of water supply. Many factors such as slope and the level of ground water and soil permeability are to be considered. Recommended safe distance between the drinking water well and the latrine is 15 m. A latrine is more likely to be kept clear if it is located close to the house or other buildings which it serves.
No comments:
Post a Comment