Excreta
There are different ways of getting rid of excreta:1. Pit latrines.
2. Bucket latrines.
3. The water carriage system: septic tank; aqua privy; water-borne sewage with flush toilets.
Pit Latrines
Pit latrines should be dug after consulting the health inspector. The site should be suitably placed away from water supplies and not too near the house. The pit should have a cover and should be cleaned every day to avoid flies. It should be 15 feet deep initially, if possible, and a new one should be constructed before it is nearly full.Bucket Latrines or Closets
Bucket latrines are so constructed that the bucket receives the excreta. They have to be emptied every day by the local authority and the 'night soil' taken to the sewage works. This is not, however, a satisfactory method and costs money to maintain as staff must always be employed.Water Carriage System
Water carriage is used in towns where there is a good deal of sewage from the many homes. The waste water and sewage are collected by different pipes from houses and run into a sewer, which is a big pipe under the road outside the house.This runs into a sewage works (or in the country, a septic tank or cesspool) being joined by other pipes on the way. In the sewage works the excreta flows from the main sewer through a large screen removing rubbish such as paper, etc. It then flows into a grit channel to remove sand and grit and from here it flows into a settling tank where the solids go to the bottom: this is called sludge; the fluids remain on top. The fluid is made pure by exposing it to air and special bacteria, while sprinkling it over rough stones in filters which are coated with this bacteria; the fluid is then drained off into a nearby river or lake. The sludge is taken off separately, digested in tanks, dried, and sold as manure for gardens.
Septic Tank
Septic tank is used where there are no sewage works, but where there is a water carriage system, for example in a house, or a hospital, or a mission or large school.The sewage is carried by pipes into a big tank some distance from the building. Scum (a dirty skin) forms on top of the tank and the special bacteria working in the sewage underneath the scum make it harmless. Every few months or years the solid matter must be emptied–this is sludge. The harmless fluid very slowly flows away into a soak pit and then through the soil. The tank is built into the ground and always kept covered.
It is important that every home should have some system of disposal of human excreta, because this can contain the bacteria of typhoid and dysentery and gastro-enteritis, the viruses of infective hepatitis and poliomyelitis, the amoebae which cause amoebiasis and the ova of worms such as hookworm, ascaris, and tapeworm. In many parts of the world the germs of cholera could be included in this list. The germs of can contaminate food, milk, or water either directly or by contaminated hands or can spread by flies. The ideal system of disposal ensures that:
1. There is no, or minimal, handling of the excreta.
2. It does not contaminate water or surface soil.
3. It is not accessible to flies or animals.
4. It is not offensive to the senses.
5. It is one that is acceptable to the community and suites the people's customs and their pockets.
People often have their own customs.
