Water purification is the process of removing undesirable chemicals, biological contaminants, suspended solids, and gases from water. The goal is to produce water that is fit for specific purposes. Most water is purified and disinfected for human consumption, but water purification may also be carried out for a variety of other purposes, including medical, pharmacological, chemical, and industrial applications. The history of water purification includes a wide variety of methods. The methods used include physical processes such as filtration, sedimentation, and distillation; 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.
Microfiltration is a type of physical filtration process where a contaminated fluid is passed through a special pore-sized membrane filter to separate microorganisms and suspended particles from process liquid. It is commonly used in conjunction with various other separation processes such as ultrafiltration and reverse osmosis to provide a product stream which is free of undesired contaminants.
Bottled water is drinking water packaged in plastic or glass water bottles. Bottled water may be carbonated or not. Sizes range from small single serving bottles to large carboys for water coolers.
Water conservation includes all the policies, strategies and activities to sustainably manage the natural resource of fresh water, to protect the hydrosphere, and to meet the current and future human demand. Population, household size and growth and affluence all affect how much water is used. Factors such as climate change have increased pressures on natural water resources especially in manufacturing and agricultural irrigation. Many countries have already implemented policies aimed at water conservation, with much success. The key activities to conserve water are as follows: any beneficial reduction in water loss, use and waste of resources, avoiding any damage to water quality; and improving water management practices that reduce the use or enhance the beneficial use of water. Technology solutions exist for households, commercial and agricultural applications. Water conservation programs involved in social solutions are typically initiated at the local level, by either municipal water utilities or regional governments. Common strategies include public outreach campaigns, tiered water rates, or restrictions on outdoor water use such as lawn watering and car washing.
A water filter removes impurities by lowering contamination of water using a fine physical barrier, a chemical process, or a biological process. Filters cleanse water to different extents, for purposes such as: providing agricultural irrigation, accessible drinking water, public and private aquariums, and the safe use of ponds and swimming pools.
Biofiltration is a pollution control technique using a bioreactor containing living material to capture and biologically degrade pollutants. Common uses include processing waste water, capturing harmful chemicals or silt from surface runoff, and microbiotic oxidation of contaminants in air. Industrial biofiltration can be classified as the process of utilizing biological oxidation to remove volatile organic compounds, odors, and hydrocarbons.
Slow sand filters are used in water purification for treating raw water to produce a potable product. They are typically 1–2 m (3.3–6.6 ft) deep, can be rectangular or cylindrical in cross section and are used primarily to treat surface water. The length and breadth of the tanks are determined by the flow rate desired by the filters, which typically have a loading rate of 200–400 litres (0.20–0.40 m3) per square metre per hour.
The Louisville Water Company is a water company based in Louisville, Kentucky.
American Water Works Association (AWWA) is an international non-profit, scientific and educational association founded to improve water quality and supply. Established in 1881, it is a lobbying organization representing a membership of around 50,000 members worldwide.
A combination of aqueducts, reservoirs, and tunnels supplies fresh water to New York City. With three major water systems stretching up to 125 miles (201 km) away from the city, its water supply system is one of the most extensive municipal water systems in the world.
The rapid sand filter or rapid gravity filter is a type of filter used in water purification and is commonly used in municipal drinking water facilities as part of a multiple-stage treatment system.
Water supply and sanitation in the United States involves a number of issues including water scarcity, pollution, a backlog of investment, concerns about the affordability of water for the poorest, and a rapidly retiring workforce. Increased variability and intensity of rainfall as a result of climate change is expected to produce both more severe droughts and flooding, with potentially serious consequences for water supply and for pollution from combined sewer overflows. Droughts are likely to particularly affect the 66 percent of Americans whose communities depend on surface water. As for drinking water quality, there are concerns about disinfection by-products, lead, perchlorates, PFAS and pharmaceutical substances, but generally drinking water quality in the U.S. is good.
The Philadelphia Water Department is the public water utility for the City of Philadelphia. PWD provides integrated potable water, wastewater, and stormwater services for Philadelphia and some communities in Bucks, Delaware and Montgomery counties. PWD is a municipal agency of the City of Philadelphia, and is seated in rented space at the Jefferson Tower in the Market East area of Center City, Philadelphia.
George Warren Fuller was an American sanitary engineer who was also trained in bacteriology and chemistry. His career extended from 1890 to 1934 and he was responsible for important innovations in water and wastewater treatment. He designed and built the first modern water filtration plant, and he designed and built the first chlorination system that disinfected a U.S. drinking water supply. In addition, he performed groundbreaking engineering work on sewage treatment facilities in the U.S. He was President of both the American Water Works Association and the American Public Health Association, and he was recognized internationally as an expert civil and sanitary engineer.
John Laing Leal was a physician and water treatment expert who, in 1908, was responsible for conceiving and implementing the first disinfection of a U.S. drinking water supply using chlorine. He was one of the principal expert witnesses at two trials which examined the quality of the water supply in Jersey City, New Jersey, and which evaluated the safety and utility of chlorine for production of "pure and wholesome" drinking water. The second trial verdict approved the use of chlorine to disinfect drinking water which led to an explosion of its use in water supplies across the U.S.
Allen Hazen was an expert in hydraulics, flood control, water purification and sewage treatment. His career extended from 1888 to 1930 and he is, perhaps, best known for his contributions to hydraulics with the Hazen-Williams equation. Hazen published some of the seminal works on sedimentation and filtration. He was President of the New England Water Works Association and Vice President of the American Society of Civil Engineers.
George Chandler Whipple was an American civil engineer and an expert in the field of sanitary microbiology. His career extended from 1889 to 1924 and he is best known as a co-founder of the Harvard School of Public Health. Whipple published some of the most important books in the early history of public health and applied microbiology.
John Robert Baylis was an American chemist and sanitary engineer. His career extended from about 1905 to 1963 and he is best known for his work in applied research to improve drinking water purification.
Water chlorination is the process of adding chlorine or chlorine compounds such as sodium hypochlorite to water. This method is used to kill bacteria, viruses and other microbes in water. In particular, chlorination is used to prevent the spread of waterborne diseases such as cholera, dysentery, and typhoid.
A Jewell water filter was a system of sand filters for filtering and treating water for drinking purposes that made use of gravity to allow water to percolate through a column of sand inside cylindrical cisterns that was widely used in the early twentieth century. They are named after Omar Hestrian Jewell established Jewell Pure Water Company in Chicago in 1890 and managed later by two of his sons. Jewell water filters were used in many city water supply systems across the world and modified versions continue to be in use.
