Water treatment

A water treatment plant in northern Portugal.

Water treatment describes those processes used to make water more acceptable for a desired end-use. These can include use as drinking water, industrial processes, medical and many other uses. The goal of all water treatment process is to remove existing contaminants in the water, of reduce the concentration of such contaminants so it becomes fit for its desired end-use. One such use is returning water that has been used back into the natural environment without adverse ecological impact.

The processes involved in treating water may be physical such as settling, chemical such as disinfection or coagulation, or biological such as lagooning, slow sand filtration or activated sludge.

Potable water purification

Main article: water purification

Abandoned Water Purification Plant Springfield, Tennessee

Water purification is the removal of contaminants from untreated water to produce drinking water that is pure enough for its intended use, most commonly human consumption. Substances that are removed during the process of drinking water treatment include bacteria, algae, viruses, fungi, minerals such as iron and sulphur, and man-made chemical pollutants.

Sewage treatment

Main article: Sewage treatment

Sewage treatment is the process that removes the majority of the contaminants from wastewater or sewage and produces both a liquid effluent suitable for disposal to the natural environment and a sludge. To be effective, sewage must be conveyed to a treatment plant by appropriate pipes and infrastructure and the process itself must be subject to regulation and controls. Some wastewaters require different and sometimes specialized treatment methods. At the simplest level, treatment of sewage and most wastewaters is carried out through separation of solids from liquids, usually by settlement. By progressively converting dissolved material into solids, usually a biological floc which is then settled out, an effluent stream of increasing purity is produced.

The need for water treatment in developing countries

As of 2006, waterborne diseases are estimated to cause 1.8 million deaths each year. These deaths are attributable to inadequate public sanitation systems and it is clear that proper sewerage (or other options as small-scale water treatment) need to be installed.

Appropriate technology options in water treatment include both community-scale and household-scale point-of-use (POU) designs.

External links

• Nanotechnology-enabled Water Treatment-Project NeWT, Center for Biological and Environmental Nanotechnology (CBEN), Rice University
• National Safety Foundation, rules for equipment that contacts drinking water
• Water Softener Reviews
• Code of Federal Register - CFR Title 21 Part 129 Helpful information and water tank installation instructions
• picture story by German photographer Marc Steinmetz