of Public Health & Preventive Medicine
CUM ACTION PROJECT
WATER SEAL LATRINE:
Research Cum Action Project at Tamil Nadu, financed by the Ford
Foundation and Ministry of Health, Government of India, has its
genesis in 1956. The major objective of the project was to
improve Educational Methods, Conducting Systematic Research in
various Public Health Programmes and to evolve a Low Cost Sanitary
Latrine suitable for the rural household.
Pour-flush Latrine consists of a squatting pan of a special design,
having a steep gradient at the bottom and a particular depth and a
trap having 20 mm waterseal. This is so designed that the human
excreta of one person can be flushed by pouring nearly 2 litres of
water. The excreta is discharged into the leaching pits.
The squatting pan is connected to the leaching pit through a
pipe. These pits are lined with honey comb brick work or open
joined stones, so as to allow the liquid in the pits to percolate and
gases to be absorbed into the soil; and at the same time preventing
the pit from collapsing. The sludge gets digested and settles
pits are used alternately. When one pit is filled, it is
stopped being used and the excreta is diverted to the second
pit. The filled up pit is left unused; and in about 24 months
the contents become rich organic humus, innocuous, free of pathogen
and smell. When convenient, it is emptied and contents could be
used as fertiliser. It is then ready to put back into use when
the second pit becomes full in its turn.
simple care and cleaning by the household, the pour-flush latrine is
a very satisfactory and hygienic sanitation system. They can be
located inside the house, since water-seal prevents odour or insect nuisance.
size of leach pits depends on factors such as : soil
characteristics, sub-soil water level, interval of cleaning, number
of users and people's food habit. The dimensions of the
leaching pits for 5 number of users for three years is 900 mm
internal diameter and 1100 mm effective depth. The pits should
be located 8m away from the drinking water sources.
of pour-flush latrines is very easy and simple. Day-to-day
maintenance consists only of washing the latrine floor and cleaning
the pan. No other maintenance cost is needed. The cost of
cleaning the pits can be covered by sale of humus obtained from the pits.
squatting pan and trap can be ceramic, fibre glass reinforced
polyester plastic (GRP) or cement.
cost of construction of a pour-flush latrine with single pit without
super structure works out at Rs.2,100/-
more details and guidance, contact:
The Deputy Director,
Institute of Public Health,
Poonamallee, Chennai-600 056.
The Health Educator (Medical),
Public Health Engineer,
Public Health Engineer,