SANITARY LATRINE
A sanitary latrine is one which fulfils the following criteria:
(1) Excreta should not contaminate the ground or surface water
(2) Excreta should not pollute the soil
(3) Excreta should not be accessible to flies, rodents, animals (pigs, dogs, cattle etc.) and other vehicles of transmission.
(4) Excreta should not create a nuisance due to odour or unsightly appearance.
Some of the well known types of sanitary latrines are :-
BORE HOLE LATRINE
The bore hole latrine is the forerunner of the non-service type of latrines .The latrine consists of a circular hole 30 to 40 cm (12-16 in.) in diameter, dug vertically into the ground to a depth of 4 to 8 m (13-26 ft.), most commonly 6 m (20 ft.). A special equipment known as auger is required to dig a bore hole.
A nightsoil undergoes purification by anaerobic digestion and is eventually converted into a harmless mass The amount of sludge that accumulates has been estimated to amount to 2.1 to 7.3 cubic feet per 1.000 users days .The bore hole latrine is therefore, not very much in se today. It has been superseded by better innovations
DUG WELL LATRINE
Dug well latrine or pit latrine is an improvement over the bore hole latrine circular pit about 75 cm (30 in.) in diameter and 3 to 3.5 m (10-12 ft.) deep is dug into the ground for the reception of the nightsoil.
The action of the dug well latrine is the same as in the bore hole latrine, i.e., anaerobic digestion.
WATER SEAL LATRINE
The squatting plate is fitted with a water seal.
The water seal performs two important functions(1) it prevents access by flies(2) it prevents escape of odours and foul gases and thereby eliminates the nuisance from smell .
Once the latrine is flushed, nightsoil is no longer visible. These merits have rendered the water seal type of latrine more acceptable to rural people than the bore hole or pit privy without water seal .Two types have gained recognition for wide use. These are:
(1) the P.R.A.I. type, evolved by the Planning. Research and Action Institute, Lucknow (Uttar Pradesh) and
(2) the RCA type.
