2.5 Excreta and faecal sludge

Human excreta is of immediate health concern to communities because:

  • a.Faeces contain pathogens that cause disease. Children under five years of age are particularly vulnerable.
  • b.In many urban areas, faeces are currently not contained, collected and disposed of safely.

The combined effect of the presence of pathogens and inefficiencies in waste management systems leads to an increasing risk of new infection. If these problems can be brought under control the health risks associated with infection as a result of contact with faecal matter can be avoided.

  • Of the two reasons (a) and (b) given above, which do you think might be easier for us to control?

  • It is easier to control (b). Human faeces always contain pathogens and there is nothing we can do about it. However, we can manage how faeces are disposed of and prevent contamination of the environment.

Pit latrines and septic tanks are appropriate sanitation options but they must be properly built and maintained to reduce the risk of groundwater contamination. In particular, latrines should be lined with an impermeable (watertight) material. If they are just lined with stone walls, the contents of the pit will seep out near the surface and pathogens in faeces may eventually be washed out into the surrounding soil. From there they can contaminate groundwater, nearby rivers, springs or water pipes. People will eventually drink the contaminated water. Contamination from animal faeces may also be an issue. For example chicken excrement can contain high levels of pathogenic bacteria, which can cause health issues for humans.

Flying toilets are particularly dangerous because human faeces are discarded close to where people are conducting their daily chores. Flies thrive and breed on faeces and organic wastes. They can easily transfer faeces to the food or water we use, ultimately leading to pathogens being ingested by people living in the nearby communities, resulting in disease.

Open defecation is the practice of excreting faeces in the open rather than in a latrine, and is common practice in highly populated corners of urban areas, as well as in peri-urban settings where adequate latrines are not available. People practise open defecation because there is no suitable alternative. The possibility of pathogens from faeces reinfecting people is very high in this situation.

Where latrines are available, they may become overfull if not emptied regularly. As a result, faecal matter may overflow the pit and become a contamination risk in the same way as open defecation or flying toilets.

Faecal waste that accumulates in the bottom of pits and septic tanks is called faecal sludge, septic sludge or simply sludge. Inefficiencies in sludge management systems can increase the chances of contaminating the environment during collection, transport or disposal of sludge.

Management and appropriate disposal of human excreta is a key environmental issue. It is important to remember the inevitable link between human excreta and disease. That is why building latrines, encouraging their proper use and promoting handwashing stand out as key strategic interventions to reduce the incidence of disease.

2.4 Surface and groundwater

2.6 Air pollution