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Slow Sand Filters
Slow sand filters are used in water purification for treating raw water to produce a potable product. They are typically 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 per square metre per hour. Slow sand filters differ from all other filters used to treat drinking water in that they work by using a complex biological film that grows naturally on the surface of the sand. The sand itself does not perform any filtration function but simply acts as a substrate, unlike its counterparts for ultraviolet and pressurized treatments. Although they are often preferred technology in many developing countries because of their low energy requirements and robust performance, they are also used to treat water in some developed countries, such as the UK, where they are used to treat water supplied to London. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Slow Sand Filter Profile
In everyday use and in kinematics, the speed (commonly referred to as ''v'') of an object is the magnitude of the change of its position over time or the magnitude of the change of its position per unit of time; it is thus a scalar quantity. The average speed of an object in an interval of time is the distance travelled by the object divided by the duration of the interval; the instantaneous speed is the limit of the average speed as the duration of the time interval approaches zero. Speed is not the same as velocity. Speed has the dimensions of distance divided by time. The SI unit of speed is the metre per second (m/s), but the most common unit of speed in everyday usage is the kilometre per hour (km/h) or, in the US and the UK, miles per hour (mph). For air and marine travel, the knot is commonly used. The fastest possible speed at which energy or information can travel, according to special relativity, is the speed of light in a vacuum ''c'' = metres per second (approx ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Germ Theory Of Disease
The germ theory of disease is the currently accepted scientific theory for many diseases. It states that microorganisms known as pathogens or "germs" can lead to disease. These small organisms, too small to be seen without magnification, invade humans, other animals, and other living hosts. Their growth and reproduction within their hosts can cause disease. "Germ" refers to not just a bacterium but to any type of microorganism, such as protists or fungi, or even non-living pathogens that can cause disease, such as viruses, prions, or viroids. Diseases caused by pathogens are called infectious diseases. Even when a pathogen is the principal cause of a disease, environmental and hereditary factors often influence the severity of the disease, and whether a potential host individual becomes infected when exposed to the pathogen. Pathogens are disease-carrying agents that can pass from one individual to another, both in humans and animals. Infectious diseases are caused by biological a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Schmutzdecke
Schmutzdecke (German, "dirt cover" or dirty skin, sometimes wrongly spelled schmutzedecke) is a hypogeal biological layer formed on the surface of a slow sand filter. The schmutzdecke is the layer that provides the effective purification in potable water treatment, the underlying sand providing the support medium for this biological treatment layer. The composition of any particular schmutzdecke varies, but will typically consist of a gelatinous biofilm matrix of bacteria, fungi, protozoa, rotifera and a range of aquatic insect larvae. As a schmutzdecke ages, more algae tend to develop, and larger aquatic organisms may be present including some bryozoa, snails and annelid The annelids (Annelida , from Latin ', "little ring"), also known as the segmented worms, are a large phylum, with over 22,000 extant species including ragworms, earthworms, and leeches. The species exist in and have adapted to various ecol ... worms. References * {{cite web, url=http://www.owp.csus.edu/ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypogeal
Hypogeal, hypogean, hypogeic and hypogeous (; ) are biological terms describing an organism's activity below the soil surface. In botany, a seed is described as showing hypogeal germination when the cotyledons of the germinating seed remain non-photosynthetic, inside the seed shell, and below ground.{{cite book, author1=Adrian D. Bell, author2=Alan Bryan, title=Plant Form: An Illustrated Guide to Flowering Plant Morphology, url=https://books.google.com/books?id=SM3khPHXhKEC&pg=PA200, year=2008, publisher=Timber Press, isbn=978-0-88192-850-1, page=200 The converse, where the cotyledons expand, throw off the seed shell and become photosynthetic above the ground, is epigeal germination. In water purification works, the hypogeal (or Schmutzdecke) layer is a biological film just below the surface of slow sand filters. It contains microorganisms that remove bacteria and trap contaminant particles. The terms hypogean and hypogeic are used for fossorial ( burrowing) and troglobitic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biofilm
A biofilm comprises any syntrophic consortium of microorganisms in which cells stick to each other and often also to a surface. These adherent cells become embedded within a slimy extracellular matrix that is composed of extracellular polymeric substances (EPSs). The cells within the biofilm produce the EPS components, which are typically a polymeric conglomeration of extracellular polysaccharides, proteins, lipids and DNA. Because they have three-dimensional structure and represent a community lifestyle for microorganisms, they have been metaphorically described as "cities for microbes". Biofilms may form on living or non-living surfaces and can be prevalent in natural, industrial, and hospital settings. They may constitute a microbiome or be a portion of it. The microbial cells growing in a biofilm are physiologically distinct from planktonic cells of the same organism, which, by contrast, are single cells that may float or swim in a liquid medium. Biofilms can form ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Slow Sand Filter Room
In everyday use and in kinematics, the speed (commonly referred to as ''v'') of an object is the magnitude of the change of its position over time or the magnitude of the change of its position per unit of time; it is thus a scalar quantity. The average speed of an object in an interval of time is the distance travelled by the object divided by the duration of the interval; the instantaneous speed is the limit of the average speed as the duration of the time interval approaches zero. Speed is not the same as velocity. Speed has the dimensions of distance divided by time. The SI unit of speed is the metre per second (m/s), but the most common unit of speed in everyday usage is the kilometre per hour (km/h) or, in the US and the UK, miles per hour (mph). For air and marine travel, the knot is commonly used. The fastest possible speed at which energy or information can travel, according to special relativity, is the speed of light in a vacuum ''c'' = metres per second (approx ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Poughkeepsie, New York
Poughkeepsie ( ), officially the City of Poughkeepsie, separate from the Town of Poughkeepsie around it) is a city in the U.S. state of New York. It is the county seat of Dutchess County, with a 2020 census population of 31,577. Poughkeepsie is in the Hudson River Valley region, midway between the core of the New York metropolitan area and the state capital of Albany. It is a principal city of the Poughkeepsie–Newburgh–Middletown metropolitan area which belongs to the New York combined statistical area. It is served by the nearby Hudson Valley Regional Airport and Stewart International Airport in Orange County, New York. Poughkeepsie has been called "The Queen City of the Hudson". It was settled in the 17th century by the Dutch and became New York State's second capital shortly after the American Revolution. It was chartered as a city in 1854. Major bridges in the city include the Walkway over the Hudson, a former railroad bridge called the Poughkeepsie Bridge which r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Teddington Lock
Teddington Lock is a complex of three lock (water transport), locks and a weir on the River Thames between Ham, London, Ham and Teddington in the London Borough of Richmond upon Thames, England. Historically in Middlesex, it was first built in 1810. The limit of legal powers between the Port of London Authority, the navigation authority downstream to the North Sea and that upstream to small headwaters of the river, the Environment Agency, is marked nearby by an obelisk on the "Surrey" (Thames Path, towpath, right) bank. The weir named Teddington Weir marks the river's usual tidal limit and is the lowest on the Thames. This lock is the lowest full-tide lock and second lowest of all-tide locks on the Thames. The complex of civil engineering or infrastructure in essence consists of a large long weir and three locks: a conventional launch lock in regular use, very large barge lock and a small Thames skiff, skiff lock. The barge lock was made to accommodate long barges, steame ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thames
The River Thames ( ), known alternatively in parts as the River Isis, is a river that flows through southern England including London. At , it is the longest river entirely in England and the second-longest in the United Kingdom, after the River Severn. The river rises at Thames Head in Gloucestershire, and flows into the North Sea near Tilbury, Essex and Gravesend, Kent, via the Thames Estuary. From the west it flows through Oxford (where it is sometimes called the Isis), Reading, Henley-on-Thames and Windsor. The Thames also drains the whole of Greater London. In August 2022, the source of the river moved five miles to beyond Somerford Keynes due to the heatwave in July 2022. The lower reaches of the river are called the Tideway, derived from its long tidal reach up to Teddington Lock. Its tidal section includes most of its London stretch and has a rise and fall of . From Oxford to the Estuary the Thames drops by 55 metres. Running through some of the drier parts of mai ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metropolitan Commission Of Sewers
The Metropolitan Commission of Sewers was one of London's first steps towards bringing its sewer and drainage infrastructure under the control of a single public body. It was absorbed by the Metropolitan Board of Works on 1 January 1856. Formation The commission was formed by the Metropolitan Commission of Sewers Act 1848 (11 & 12 Vict., c. 112), partly in response to public health concerns following serious outbreaks of cholera. The commission's mandate was renewed and amended with supplementary Acts in 1851, 1852, 1853, 1854 and 1855. Commissioners included Sir Edwin Chadwick, Robert Stephenson and Thomas Field Gibson. The new body combined eight local boards of commissioners that had been established by earlier acts of parliament: * Tower Hamlets Commission of Sewers * St Katharine's Commission of Sewers * Poplar and Blackwall Commission of Sewers * Holborn and Finsbury Commission of Sewers * Westminster and Middlesex Commission of Sewers * Surrey and Kent Commission of Se ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Europe
Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia and it is located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. Comprising the westernmost peninsulas of Eurasia, it shares the continental landmass of Afro-Eurasia with both Africa and Asia. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south and Asia to the east. Europe is commonly considered to be Boundaries between the continents of Earth#Asia and Europe, separated from Asia by the drainage divide, watershed of the Ural Mountains, the Ural (river), Ural River, the Caspian Sea, the Greater Caucasus, the Black Sea and the waterways of the Turkish Straits. "Europe" (pp. 68–69); "Asia" (pp. 90–91): "A commonly accepted division between Asia and E ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Water Supply
Water supply is the provision of water by public utilities, commercial organisations, community endeavors or by individuals, usually via a system of pumps and pipes. Public water supply systems are crucial to properly functioning societies. These systems are what supply drinking water to populations around the globe. Aspects of service quality include continuity of supply, water quality and water pressure. The institutional responsibility for water supply is arranged differently in different countries and regions (urban versus rural). It usually includes issues surrounding policy and regulation, service provision and standardization. The cost of supplying water consists, to a very large extent, of fixed costs (capital costs and personnel costs) and only to a small extent of variable costs that depend on the amount of water consumed (mainly energy and chemicals). Almost all service providers in the world charge tariffs to recover part of their costs. Water supply is a separate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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