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close this bookA Guide to the Development of on-site Sanitation (WHO; 1992; 246 pages)
View the documentPreface
close this folderPart I. Foundations of sanitary practice
open this folder and view contentsChapter 1. The need for on-site sanitation
open this folder and view contentsChapter 2. Sanitation and disease transmission
open this folder and view contentsChapter 3. Social and cultural considerations
close this folderChapter 4. Technical options
View the documentOpen defecation
View the documentShallow pit
View the documentSimple pit latrine
View the documentBorehole latrine
View the documentVentilated pit latrine
View the documentPour-flush latrine
View the documentSingle or double pit
View the documentComposting latrine
View the documentSeptic tank
View the documentAqua-privy
View the documentRemoval systems for excreta
open this folder and view contentsPart II. Detailed design, construction, operation and maintenance
open this folder and view contentsPart III. Planning and development of on-site sanitation projects
View the documentReferences
View the documentSelected further reading
View the documentGlossary of terms used in this book
View the documentAnnex 1. Reuse of excreta
View the documentAnnex 2. Sullage
View the documentAnnex 3. Reviewers
View the documentSelected WHO publications of related interest
View the documentBack Cover

Removal systems for excreta

Overhung latrine

A latrine built over the sea, a river, or other body of water into which excreta drop directly, is known as an overhung latrine. If there is a strong current in the water the excreta are carried away. Local communities should be warned of the danger to health resulting from contact with or use of water into which excreta have been discharged.



May be the only feasible system for communities living over water

Serious health risks



Bucket latrine

This latrine has a bucket or other container for the retention of faeces (and sometimes urine and anal cleaning material), which is periodically removed for treatment or disposal. Excreta removed in this way are sometimes termed nightsoil.



Low initial cost



Creates fly nuisance


Danger to health of those who collect or use the nightsoil


Collection is environmentally and physically undesirable

Vaults and cesspits

In some areas, watertight tanks called vaults are built under or close to latrines to store excreta until they are removed by hand (using buckets or similar receptacles) or by vacuum tanker. Similarly, household sewage may be stored in larger tanks called cesspits, which are usually emptied by vacuum tankers. Vaults or cesspits may be emptied when they are nearly full or on a regular basis.



Satisfactory for users where there is a reliable and safe collection service

High construction and collection costs


Removal by hand has even greater health risks than bucket latrines


Irregular collection can lead to tanks overflowing


Efficient infrastructure required


Discharge from WCs and other liquid wastes flow along a system of sewers to treatment works or directly into the sea or a river.



User has no concern with what happens after the WC is flushed

High construction costs

No nuisance near the household

Efficient infrastructure required for construction, operation and maintenance

Treated effluent can be used for irrigation

Ample and reliable piped water supply required (a minimum of 70 litres per person per day is recommended)


If discharge is to a water-course, adequate treatment required to avoid pollution

Sewers of smaller diameter than usual (small-bore sewerage), sewers built nearer to the surface than usual, and sewers with flatter gradient than usual have been tried. Many of these systems require a chamber at each house to retain solids, which have to be removed and disposed of from time to time. Some of these systems have been found to be suitable for providing sanitation simultaneously for a large number of high-density dwellings.


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