Summary of Week 1 of Introduction to Household Water Treatment and Safe Storage (Coursera – École Polytechnique Fédérale de Lausanne)
There are many diseases caused by poor water, sanitation and hygiene. In particular, diarrhea is a leading cause of mortality and morbidity.
Diseases related to poor water, sanitation and hygiene can be classified according to its transmission pathways: waterborne, water-washed, water-based and water-related. This is the Bradley classification, and informs the selection of appropriate control mechanisms.
These diseases are caused by pathogens that can be described by its biological type: protozoa, bacteria, viruses and helminths. These are transmitted through pathways illustrated by the F-diagram.
Because it is impractical to measure all pathogens, faecal indicators area used. Escherichia coli (E.coli) is generally considered the most suitable, although it does not necessarily co-relate to contamination risk. A more complete picture can be obtained by also doing a sanitary inspection. Contamination can occur at the point of the water resource, delivery, collection and transport, household storage, and consumption.
Household water treatment offers the opportunity to remove contamination that occurs before consumption. Treatment processes include sedimentation (pre-treatment), filtration, boiling, UV radiation (solar disinfection) and chlorine. Each process has different levels of effectiveness and different applications.