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fermer ce livreA Guide to the Development of on-site Sanitation (WHO; 1992; 246 pages)
Afficher le documentPreface
fermer ce répertoirePart I. Foundations of sanitary practice
ouvrir ce répertoire et afficher son contenuChapter 1. The need for on-site sanitation
ouvrir ce répertoire et afficher son contenuChapter 2. Sanitation and disease transmission
ouvrir ce répertoire et afficher son contenuChapter 3. Social and cultural considerations
fermer ce répertoireChapter 4. Technical options
Afficher le documentOpen defecation
Afficher le documentShallow pit
Afficher le documentSimple pit latrine
Afficher le documentBorehole latrine
Afficher le documentVentilated pit latrine
Afficher le documentPour-flush latrine
Afficher le documentSingle or double pit
Afficher le documentComposting latrine
Afficher le documentSeptic tank
Afficher le documentAqua-privy
Afficher le documentRemoval systems for excreta
ouvrir ce répertoire et afficher son contenuPart II. Detailed design, construction, operation and maintenance
ouvrir ce répertoire et afficher son contenuPart III. Planning and development of on-site sanitation projects
Afficher le documentReferences
Afficher le documentSelected further reading
Afficher le documentGlossary of terms used in this book
Afficher le documentAnnex 1. Reuse of excreta
Afficher le documentAnnex 2. Sullage
Afficher le documentAnnex 3. Reviewers
Afficher le documentSelected WHO publications of related interest
Afficher le 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.

Advantages

Disadvantages

May be the only feasible system for communities living over water

Serious health risks

Cheap

 

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.

Advantages

Disadvantages

Low initial cost

Malodorous

 

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.

Advantages

Disadvantages

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

Sewerage

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

Advantages

Disadvantages

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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