Nightsoil
- Slovak term: Slovenský termín
- Human excrete, with or without anal cleaning material, which are deposited in a bucket or other receptacle for manual removal (often taking place at night) (WHO 1992).
- Untreated excreta transported without water, e.g. via containers or buckets; often used as a popular term in an unspecific manner to designate faecal matter of any origin; its technical use is therefore not recommended (WHO 2006).
Explanation
Human excrete should be regarded as a natural resource to be conserved and reused under careful control rather than being discarded. Excreta for reuse may be derived from nightsoil, including that collected by municipal systems or private contractors, and the nightsoil of individual households or groups of households and used on their own gardens or farms.
Human excrete are a rich source of nitrogen and other nutrients necessary for plant growth. The most common method of reuse is direct application to the soil as a fertilizer. Nightsoil contains about 0.6% nitrogen, 0.2% phosphorus and 0.3% potassium, all of which are valuable plant nutrients. The humus formed by decomposed faeces also contains trace elements which reduce the susceptibility of plants to parasites and diseases. Humus improves the soil structure, enhancing its water-retaining qualities and encouraging better root structure of plants. Soil containing humus is less subject to erosion by wind and water and is easier to cultivate.
For centuries, untreated nightsoil has been widely used as a fertilizer, although there is an increasing awareness of the public health dangers involved. Pathogens of all kinds can remain viable in the soil and on crops. Death of pathogens on crops is usually caused by desiccation and direct sunlight, so pathogens are generally more persistent in humid cloudy climates than in arid areas (WHO 1992).
Example
“Duckweed is also cultivated in small ponds fertilized directly with nightsoil from a latrine in Bangladesh and is harvested for feeding to fish in nearby ponds. Cartage of nightsoil (manually on foot or bicycle, by boat, or by vacuum truck), and to a lesser extent septage, for use as a fish pond fertilizer is widespread in China and Vietnam.” (WHO 1992)
References
- WHO (1992) A guide to the development of on-site sanitation
- WHO (2006) Guidelines for the safe use of wastewater, excreta and greywater
