Commonly, on-site sanitation is equivalent to ‘household latrine’, but may also include facilities shared by several households living together on the same site. The more commonly known on-site sanitation includes facilities which are self-contained within the site, in contrast to sewerage where Sewage is removed from the site.
Amongst some sector professionals there is a general feeling that on-site sanitation is appropriate for rural areas and it is generally unsuitable in the urban context. In practice, given the continuous growth of urban populations and the high incidence of low-income people in slums and periurban areas, there is no possibility of providing all urban inhabitants with sewerage. Well maintained and constructed on-site/plot systems offer a viable alternative to sewerage system.
Requirements of On-site Sanitation
Requirements for adoption of on-site sanitation are:
Advantages of on-site sanitation are:
Disadvantages of on-site sanitation are:
ON-SITE SANITATION TECHNOLOGIES
The following on-sanitation technologies are being used around the world:
The use of pit latrines is extremely common in rural areas or amongst the poorer segments of society in developing countries. They are principally based on hiding human excreta in deep pits (drop and store), as opposed to flushing away and diluting them in rivers and lakes (flush and discharge). Pit latrines are designed for the onsite disposal of human excreta, with no or very little water use. They consist of a concrete squatting plate or riser, which is placed over an earthen pit. The design life varies from 5 to 10 years depending on the number of users. Often, the pits fill up faster than originally expected. The pit diameter is between 1.0 and 1.5 m. The depth of the pit is at least 2.0 m, but usually more than 3.0 m. The top 0.5 m of the pit requires lining. In loose soil, the entire pit should be lined in order to prevent collapse. The liquid (urine and water) content of faeces is normally designed to be absorbed into the soil. One unit can serve one or several households. Pit latrines are simple and relatively low cost but have many drawbacks as detailed below.
Disadvantages of Pit latrines
Ventilated Improved Pit Latrines
A conventional pit latrine can be upgraded to a ventilated improved pit (VIP) latrine. The VIP latrine is shown in fig has a vent pipe to improve ventilation. These types of latrines are also often designed as a double-vault system, where one vault is left to dry, while the other vault is being filled. Drying of the faeces is also much less effective