In the aftermath of a disaster, one of the immediate requirements for displaced people is a supply
of water, for both drinking and washing purposes. Since the reconstruction process can take many
years to be completed, this supply must be sustainable. Conditions for displaced populations are
often over-crowded and lacking in sufficient sanitary infrastructure, leading to a breeding ground
for human pathogens; water supplies can easily become contaminated and the spread of disease
through water for drinking and washing can lead to serious health problems for those exposed.
Whilst it is preferable to have a clean supply of water, this is often not possible in a post-disaster
scenario, and it is necessary to treat water to reduce the risk of pathogens spreading to people.
After basic treatment has been supplied during the initial emergency stage, upgrades can be
implemented to ensure efficient and safe supplies to people as they progress through the recovery
process. The provision of infrastructure during the reconstruction process should look to reduce
vulnerability and improve living conditions at every stage.
This report draws on information from Practical Action technical briefs Water Treatment Systems
and Household Water Treatment Systems. It describes the types of contaminants often found in
water supplies in a post-disaster context, some of the treatment types available and how they can
be implemented at the different stages of the reconstruction process. An overview is given of
some water treatment technologies, with links provided to more detailed technical briefs.
The various contaminants that can be found in water supplies are grouped into three general
Biological contaminants can consist of various bacteria from faecal matter and algae for example,
but also common are parasitic organisms such as roundworms and flatworms. The lack of
sufficient sanitation in post-disaster scenarios can often lead to excreta-based contamination of
water supplies. The World Health Organisation has more details on the various biological diseases
that can be spread, available here.
Consist of particles and suspended solids; primarily found in surface water. The suspended solids
in water can provide a breeding ground for bacteria, and must be removed before consumption.
Many water sources can contain high levels of chemicals, either through pollution or natural
processes. Some examples include high concentrations of nitrates causing cyanosis, arsenic
increasing risk of cancer and fluoride causing mottling of teeth. More comprehensive details of
chemical contaminants and their effects are provided in the references at the end of this report.
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