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 lesser developed industrial base and a lower Human Development Index (HDI) relative to other countries. However, this definition is not universally agreed upon. There is also no clear agreem ...

. 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 agency of the United States. It is a United States federal agency, under the Department of Health and Human Services, and is headquartered in Atlanta, Georgi ...

and the

Pan American Health Organization The Pan American Health Organization (PAHO) is an international public health agency working to improve the health and living standards of the people of the Americas. It is part of the United Nations system, serving as the Regional Office for ...

. 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 det ...

hazard, as it is a major source of diarrheal illnesses such as

cholera Cholera is an infection of the small intestine by some strains of the bacterium ''Vibrio cholerae''. Symptoms may range from none, to mild, to severe. The classic symptom is large amounts of watery diarrhea that lasts a few days. Vomiting and ...

. Diarrheal illnesses are a significant source of mortality for children, killing more children than the combined mortality of

measles Measles is a highly contagious infectious disease caused by measles virus. Symptoms usually develop 10–12 days after exposure to an infected person and last 7–10 days. Initial symptoms typically include fever, often greater than , cough, ...

malaria Malaria is a mosquito-borne infectious disease that affects humans and other animals. Malaria causes symptoms that typically include fever, tiredness, vomiting, and headaches. In severe cases, it can cause jaundice, seizures, coma, or death. S ...

, and

AIDS Human immunodeficiency virus infection and acquired immunodeficiency syndrome (HIV/AIDS) is a spectrum of conditions caused by infection with the human immunodeficiency virus (HIV), a retrovirus. Following initial infection an individual m ...

. For children under five, diarrheal disease is the second-leading cause of death worldwide.

History and methods

In 1992, the US

(CDC) and the

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 in 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 Portable water purification devices are self-contained, easily transported units used to purify water from untreated sources (such as rivers, lakes, and wells) for drinking purposes. Their main function is to eliminate pathogens, and often al ...

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 study, pilot project, pilot test, or pilot experiment 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 pro ...

, 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 independent agency of the U.S. federal government that is primarily responsible for administering civilian foreign aid and development assistance. With a budget of over $27 bi ...

(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 st ...

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 age ...

, 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