The Water Supply Process:
Water supply systems obtain water from a variety of locations, including groundwater (aquifers), surface water (lakes and rivers), and from the sea through desalination.
The water is then, in most cases, purified, disinfected through chlorination and in the EU through the use of Hydrogen Peroxide. The use of Ultraviolet Sterilization is far more common in western Europe, than even the United States.
Treated water flows under pressure, or by gravity to surface or covered reservoirs. Reservoirs can be elevated such as water towers, or atop the ground.
Many countries around the world, but far from most, have established regulatory agencies addressing infrastructure, maintaining water quality, and the protection of consumers. Their additional goal was to improve efficiency. Regulatory agencies were to be entrusted with a variety of responsibilities, including the approval of tariff increases.
These agencies are expected to be more competent, and objective in regulating service providers, than departments of government organizations. Regulatory agencies were to be autonomous from the executive branch of government, but in many countries they have not been able to exercise any effective degree of autonomy.
The United States regulatory agencies for utilities have existed for almost a century at the level of states, and in Canada at the level of provinces.
In both countries they cover several infrastructure sectors. In many US states they are called Public Utility Commissions. For England and Wales, a regulatory agency for water (OFWAT) was created as part of the privatization of the water industry in 1989. In many developing countries, water regulatory agencies were created during the 1990s in parallel with efforts at increasing private sector participation.
Water treatment is the removing of undesirable chemicals, biological contaminants, suspended solids (SS) and gases from contaminated water. The goal is to produce water fit for the desired goal purpose. Most water is purified for human consumption, but water purification may also be designed for a variety of other purposes, including meeting the requirements of medical, pharmacological, chemical and industrial applications. In general the methods used include physical processes such as filtration, solids removal, and distillation. Other processes utilize biological processes such as slow sand filters or biologically active carbon, chemical processes such as flocculation and chlorination and the use of electromagnetic radiation such as ultraviolet light.
The purification process of water may reduce the concentration of particulate matter including suspended particles, parasites, bacteria, algae, viruses, fungi; and a range of dissolved and particulate material derived from the surfaces that water may have made contact with after falling as rain.
The standards for drinking water quality are typically set by governments or by international standards. These standards will typically set minimum and maximum concentrations of contaminants for the use that is to be made of the water.
It is not possible to tell whether water is of an appropriate quality by visual examination. Simple procedures such as boiling or the use of a household activated carbon filter are not sufficient for treating all the possible contaminants that may be present in water from an unknown source. Even natural spring water – considered safe for all practical purposes in the 19th century – must now be tested before determining what kind of treatment, if any, is needed. Chemical and microbiological analysis, while expensive, are the only way to obtain the information necessary for deciding on the appropriate method of purification.
According to a 2008 World Health Organization (WHO) report, 1.1 billion people lack access to an improved drinking water supply, 88 percent of the 4 billion annual cases of diarrheal disease are attributed to unsafe water and inadequate sanitation and hygiene, and 1.8 million people die from diarrheal diseases each year.
The World Health Organization estimates that 94 percent of these diarrheal cases are preventable through modifications to the environment, including access to safe water. Simple techniques for treating water at home, such as chlorination, filters, and solar disinfection, and storing it in safe containers could save a huge number of lives each year. Reducing deaths from waterborne diseases is a major public health goal in developing countries.