The Safe Water System (SWS) is a series of inexpensive technologies that can be applied as water quality interventions in
developing countries
A developing country is a sovereign state with a less-developed Secondary sector of the economy, industrial base and a lower Human Development Index (HDI) relative to developed countries. However, this definition is not universally agreed upon. ...
. It was developed in conjunction by the US
Centers for Disease Control and Prevention
The Centers for Disease Control and Prevention (CDC) is the National public health institutes, national public health agency of the United States. It is a Federal agencies of the United States, United States federal agency under the United S ...
and the
Pan American Health Organization
The Pan American Health Organization (PAHO) is a specialized agency of the United Nations (UN) in charge of international health cooperation in the Americas. It fosters technical cooperation among member countries to fight communicable and non ...
. As of 2014, SWS had been implemented in thirty-five countries.
Background
As of 2012, 780 million people lack access to an
improved water source
An improved water source (or improved drinking-water source or improved water supply) is a term used to categorize certain types or levels of water supply for monitoring purposes. It is defined as a type of water source that, by nature of its co ...
and 2.5 billion people (half of all people in developing countries) lack access to adequate
sanitation
Sanitation refers to public health conditions related to clean drinking water and treatment and disposal of human excreta and sewage. Preventing human contact with feces is part of sanitation, as is hand washing with soap. Sanitation systems ...
. Inadequate water sanitation is a
public health
Public health is "the science and art of preventing disease, prolonging life and promoting health through the organized efforts and informed choices of society, organizations, public and private, communities and individuals". Analyzing the de ...
hazard, as it is a major source of
diarrheal illnesses such as
cholera
Cholera () is an infection of the small intestine by some Strain (biology), strains of the Bacteria, bacterium ''Vibrio cholerae''. Symptoms may range from none, to mild, to severe. The classic symptom is large amounts of watery diarrhea last ...
. Diarrheal illnesses are a significant source of mortality for children, killing more children than the combined mortality of
measles
Measles (probably from Middle Dutch or Middle High German ''masel(e)'', meaning "blemish, blood blister") is a highly contagious, Vaccine-preventable diseases, vaccine-preventable infectious disease caused by Measles morbillivirus, measles v ...
,
malaria
Malaria is a Mosquito-borne disease, mosquito-borne infectious disease that affects vertebrates and ''Anopheles'' mosquitoes. Human malaria causes Signs and symptoms, symptoms that typically include fever, Fatigue (medical), fatigue, vomitin ...
, and
AIDS
The HIV, human immunodeficiency virus (HIV) is a retrovirus that attacks the immune system. Without treatment, it can lead to a spectrum of conditions including acquired immunodeficiency syndrome (AIDS). It is a Preventive healthcare, pr ...
. For children under five, diarrheal disease is the second-leading cause of death worldwide.
History and methods
In 1992, the US
Centers for Disease Control and Prevention
The Centers for Disease Control and Prevention (CDC) is the National public health institutes, national public health agency of the United States. It is a Federal agencies of the United States, United States federal agency under the United S ...
(CDC) and the
Pan American Health Organization
The Pan American Health Organization (PAHO) is a specialized agency of the United Nations (UN) in charge of international health cooperation in the Americas. It fosters technical cooperation among member countries to fight communicable and non ...
collaborated to reduce
waterborne disease
Waterborne diseases are conditions (meaning adverse effects on human health, such as death, disability, illness or disorders) caused by pathogenic micro-organisms that are transmitted by water. These diseases can be spread while bathing, washing ...
s in developing countries. They called the new methodology the Safe Water System (SWS); it consisted of three components:
* Water treatment at
point of use with a locally made
diluted bleach solution
* Preventing recontamination of water by safely storing treated water in containers with narrow mouths, lids, and spigots
* Education to improve the handling and sanitation of food and water
From 1994 to 1995, the CDC implemented the SWS in Bolivia in a
pilot experiment
A pilot experiment, pilot study, pilot test or pilot project is a small-scale preliminary study conducted to evaluate feasibility, duration, cost, adverse events, and improve upon the study design prior to performance of a full-scale research pr ...
, where it improved water quality and reduced diarrheal illness by 40%. Following the success of the program in Bolivia, the CDC received permission from the
Zambian Ministry of Health to conduct field trials in 1998 in
Kitwe
Kitwe is the third largest city in terms of infrastructure development (after Lusaka and Ndola) and second largest city in terms of size and population (after Lusaka) in Zambia. With a population of 517,543 (''2010 census provisional'') Kitwe is ...
, Zambia. Compared to the
control group
In the design of experiments, hypotheses are applied to experimental units in a treatment group.
In comparative experiments, members of a control group receive a standard treatment, a placebo, or no treatment at all. There may be more than one tr ...
, the households that received the SWS and education on best hygiene practices experienced a 48% reduced risk of diarrheal disease.
In response to marketing efforts by the CDC, the sanitizing solution, sold as Clorin, experienced a steep increase in demand in Zambia. In 1999, about 187,000 bottles of Clorin were sold; in 2004, over 1.8 million bottles were sold. Each bottle sanitizes enough water for one month for a family of six. Clorin is subsidized by the
United States Agency for International Development
The United States Agency for International Development (USAID) is an agency of the United States government that has been responsible for administering civilian foreign aid and development assistance.
Established in 1961 and reorganized in 1998 ...
(USAID); as of 2003, each bottle is sold for US$0.09, with USAID paying $0.33 per bottle (each bottle therefore has a net cost of $0.24 to USAID).
Household water treatment now encompasses other methods, such as use of
flocculants that cause contaminants within water to sink to the bottom of a container or float at the top where they can be more easily removed. Methods like
disinfectant
A disinfectant is a chemical substance or compound used to inactivate or destroy microorganisms on inert surfaces. Disinfection does not necessarily kill all microorganisms, especially resistant bacterial spores; it is less effective than ...
powder,
solar water disinfection
Solar water disinfection, in short SODIS, is a type of portable water purification that uses solar energy to make biologically-contaminated (e.g. bacteria, viruses, protozoa and worms) water safe to drink. Water contaminated with non-biological a ...
,
ceramic filtration, and
slow sand filtration are also incorporated.
Impact
From 1998 to 2014, the CDC implemented the SWS program in thirty-five countries. During this time period, they distributed enough sanitizing agents to clean over 137 billion liters of water. Products that the CDC has distributed as part of the Safe Water Systems includes the three-component system initially piloted in Bolivia, as well as water treatment tablets. SWS has been implemented in the following countries:
* Afghanistan
* Angola
* Benin
* Botswana
* Burkina Faso
* Burma (Myanmar)
* Burundi
* Cambodia
* Cameroon
* Côte d'Ivoire
* Democratic Republic of Congo
* Dominican Republic
* Eswatini
* Ethiopia
* Guinea
* Haiti
* India
* Kenya
* Liberia
* Madagascar
* Malawi
* Mali
* Mozambique
* Namibia
* Nepal
* Nigeria
* Pakistan
* Papua New Guinea
* Republic of Congo (Brazzaville)
* Rwanda
* Senegal
* South Sudan
* Swaziland
* Tanzania
* Uganda
* Uzbekistan
* Vietnam
* Zambia
* Zimbabwe
Because the goal of the SWS interventions is to reduce the incidence of water-borne illness, SWS technologies do not mitigate other hazards in water such as chemical contaminants. Studies of SWS interventions showed a reduction of diarrhea by 24% in Bangladesh, 25% in Guatemala, and 30% among people with HIV in rural Uganda.
References
{{reflist
Drinking water
Water treatment
Sanitation
Waterborne diseases