Pict. 7. The Main Elements of a Water Distribution System
The layout of water mains is greatly dependent on local conditions and topography.
Water mains can be divided into three classes:
1. a trunk main is the main supply line between the treatment plant and service reservoirs or water towers;
2. a secondary main is a supply line distributing water from the service reservoirs to the street service mains. In some cases they provide sup- plies to large industrial consumers;
3. service mains are the pipes along each street to which individual con- sumers are connected.
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Once water is used, wastewater is typically discharged into sewerage and treated in a wastewater treatment plant (also called a sewage treat- ment works) before being discharged into a river, lake or the sea or re- used for landscaping, irrigation or industrial use.
Sewerage (also called a sewerage system, a sewage system, a sewer system, a collecting system, drainage, sanitary piping) is intended for the provision of drainage (sewage disposal) by sewers.
A sewerage network (also called a sewer network or a drainage sys- tem) is a part of the sewerage system; it is a complex of underground pipes (pipelines) and sewers for the collection and disposal of sewage from populated localities and industrial enterprises to the sewage treat- ment works.
Plumbing [a plumbing system] is installed in a building and designed for the supply of water and the elimination of wastes. It is the system of pipes, tanks, fittings, and other apparatuses required for the water supply, heating and sanitation in a building.
The general scheme of water supply may vary depending on specific conditions.
1. What is the general scheme of water supply?
2. What sources do water supply systems get water from?
3. In most cases, water is treated and disinfected, isn’t it?
4. How is water distributed to the water consumers?
5. Is a water main a main line in a water supply system?
6. What are the basic elements of a typical distribution system?
7. What classes can water mains be divided into?
8. Where is wastewater typically discharged into?
9. Is sewerage intended for the provision of drainage or water stor- age?
10. A sewerage system is a complex of underground pipes and sewers, isn’t it? What do they serve for?
11. What is a plumbing system designed for?
12. What apparatuses does plumbing include?
13. What does the general scheme of water supply depend on?
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16. Read the following text and speak on the main components and facilities of water supply systems.
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Text С. The Main Components and Facilities of a Water Supply System
A water supply system typically consists of the following compo- nents:
1. a watershed or geographic area that collects water;
2. a source of supply, or a reservoir of raw (untreated) water (above or below ground) where the water accumulates (e.g. a lake, river, stream, spring, well, groundwater from an underground aquifer);
3. a reservoir for storing the water for use during periods when de- mand is greater than the daily consumption of water;
An underground pipeline or a ground-level conduit (an aqueduct)
for conveying the water from the source of supply to the community;
5. water treatment facilities (also called “water treatment plants [sta- tions / works]” or “water purification plants [stations / works]”) for re- moving impurities from the untreated water to make it suitable for vari- ous uses;
6. a pipe network (a distribution system of pipes, usually under- ground) for delivering the treated water to the consumers (which may be residential apartment buildings and private houses, industrial and com- mercial establishments, educational and medical institutions) and other usage points (such as fire hydrants);
7. wastewater treatment facilities (also called “wastewater treatment plants [stations / works]”, or “sewage treatment plants [stations / works]”);
8. water storage facilities (reservoirs, water tanks, or water towers for larger water systems; cisterns or pressure vessels for smaller water sys- tems). Tall buildings may also need to store water locally in pressure vessels in order for the water to reach the upper floors.
Some systems are simpler and consist only of a source of supply, a main pipeline, and a small number of distribution piping; others are more complicated and include, in addition to elements previously listed, distri- bution reservoirs, additional water pressurizing components (pumping plants / stations), and other accessories.
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All these water supply system components are integrated into water infrastructure - the stock of basic water facilities and capital equipment needed for the functioning of a country or area. |
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For the purposes of acquisition of water from a variety of natural wa- ter sources, its treatment, transmission, storage, and distribution to the consumers a number of water supply facilities are utilized:
· water intake structures [facilities];
· water-pumping facilities [stations / plants] supplying water to the point of its treatment;
· water treatment facilities [structures / stations / plants / works], also called water purification facilities [structures / stations / plants / works];
· collection [collecting / accumulator / pipeline] tanks for puri- fied water;
· water-pumping facilities [stations / plants] supplying the puri- fied water to towns, cities or industrial enterprises;
· water conduits, aqueducts, and water mains [water-supply net- works] serving for water delivery to the consumers;
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· plumbing [plumbing systems] installed in a building and de- signed for the supply of water and the elimination of wastes.
Plumbing is a system of pipes and fixtures installed in a building for the distribution and use of potable (drinkable) water and the removal of waterborne wastes. It is usually distinguished from water and sewage systems that serve a group of buildings or a city.
A complete water supply system is known as a waterworks. Some- times this term is specifically applied to pumping stations, treatment sta- tions, or storage facilities. Storage facilities are provided to reserve extra water for use when demand is high and, when necessary, to help main- tain water pressure. Treatment stations are places in which water may be filtered to remove suspended impurities, aerated to remove dissolved gases, or disinfected with chlorine, ozone, ultraviolet light, or some other agent that kills harmful bacteria and microorganisms. Sometimes hard water is softened through ion exchange. Salts of iodine and fluorine which are considered helpful in preventing goiter and tooth decay are sometimes added to water in which they lack.
Not all water supply systems are used to deliver drinking water. Sys- tems used for purposes such as industry, irrigation and fire fighting oper- ate in much the same way as systems for drinking water, but the water need not meet such high standards of purity. In most municipal systems hydrants are connected to the drinking water system except during peri- ods of extreme water shortage. Because many cities draw water from the same water body into which they discharge sewage, proper sewage treatment has become increasingly essential to the preservation of sup- plies of useful water.
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