Urban water supply systems are a complex engineering structures for collecting, lifting, purifying water, preserving it and delivering it to the consumer. It includes the following structures:
water intake structures and first lift pumping stations that supply water to places of its purification;
wastewater treatment plants;
holding tanks clean water;
pumping stations of the second and subsequent rises, supplying water to the city or to industrial enterprises;
water pipelines and water supply networks.
In urban water supply practice, there are various systems that provide consumers with water centrally. The entire variety of water supply systems can be classified according to the following criteria:
By type of natural sources used, - water pipelines that take water from surface or underground sources, and mixed consumption water supply systems;
by type of consumer– communal (city, village); fire protection; production, which, in turn, are divided by industry (water pipelines of chemical enterprises, thermal power plants, metallurgical plants, etc.);
By territorial coverage of consumers – local (for one object ) and group (or centralized) water supply systems that serve a group of objects;
according to the methods of presenting water - water pipes with by gravity (gravity) and with mechanical supply of water (using pumps);
By frequency of water use – with water circulation, with sequential use in various installations;
by nature of water use– direct-flow, reverse, sequential (with reuse water);
by type of consumer– household and drinking water, industrial, fire-fighting, agricultural;
on the complexity of customer service– integrated, incompletely separate, separate systems.
Unified system provides all three types of consumers, as a rule, with drinking water. Such systems are appropriate in cases where industry consumes potable quality water or a relatively small amount of water. These systems are simpler and have a relatively lower network construction cost, which is typically about 60% of the cost of the entire water supply system.
Incomplete separate system used when industry consumes a significant amount of water, the quality requirements of which are low. In this case, the construction of an integrated system is unprofitable, because unjustified costs of purifying water for industrial needs to drinking quality lead to a significant increase in the cost of construction and operation of the water supply system.
Separate systems provide for the construction of separate systems for drinking, industrial and fire safety needs. Such systems are very rare.
City water supply schemes differ in the set of structures necessary to provide water of the required quality and quantity. General view water supply scheme, which includes a complete set of water supply facilities, is shown in the figure. The source of water supply is natural and artificial reservoirs, rivers, underground artesian and groundwater, seas and oceans.
Water supply systems for industrial enterprises are classified according to methods of water use: direct-flow, circulating and water reuse.
IN once-through systems water, as a rule, is part of the final product (for example, in the production of mineral acids, liquid suspended complex fertilizers, etc.) or significantly changes its composition (for example, water for electrolytes in electrolyzers), and therefore its reuse is impractical . In this case, it is discharged after mixing with other wastewater into the local hydrographic network or transferred to sewage treatment plants.
IN circulating systems Reuse of water supply, when water is used primarily for cooling, it is advisable to cool the heated water (for example, in cooling towers) and supply it for reuse at the same facility. At the same time, only 3-5% of the total amount of water used is supplied from the water source to replenish its losses during circulation. Sometimes recycled water needs to not only be cooled, but also sent for treatment.
IN reuse systems water discharged by one industrial consumer can be used by another (for example, water after capturing fluorine gases in the production of superphosphate is used in the production of ammonium fluoride-hydrofluoride). This makes it possible to reduce the amount of water taken from the water source.
There are 4 water supply schemes:
1 – direct-flow system (water is discharged into reservoirs without purification). Qp.p. – irretrievable losses of water in production, Qsp. – water loss due to evaporation.
Qp.p. – water losses from industrial products,
Qisp – water loss due to evaporation.
2 – system with wastewater clarification at treatment plants.
Qos. – loss of water removed along with sludge from treatment facilities.
3
– water supply system with wastewater treatment before discharge into the reservoir
Qshl. – loss of water removed with sludge from treatment facilities.
The most widely used system.
4 – circulating water supply system. The water consumption in it is small, determined by the consumption necessary to replenish irreversible water consumption in the process of production and consumption, as well as by periodic replacement of water in circulating cycles (blowdown). At a thermal power plant with a capacity of 1 million kW, with direct-flow water supply, 1.5 km3 of water is consumed annually, with a circulating system - only 0.12 km3, i.e. 13 times less.
Entrainment – loss of water through droplet entrainment,
Qreset – water loss when purging the system,
Qadd – water taken from a water body to replenish water losses in the system.
In this water supply system, waste water after purification is not discharged into a reservoir, but is reused in the production system, undergoing regeneration after each production cycle.
5 – drainless water supply system (closed system), the most promising, but most difficult to achieve.
Water efficiency criteria
Water use efficiency can be assessed by the following three indicators combined.
The technical perfection of the water supply system is assessed by the amount of recycled water used (%)
The efficiency of using water withdrawn from a source is assessed by the utilization factor
Irreversible water consumption and losses (%)
,
where Qrev, and Qseq. – the amount of water used in circulation and sequentially;
Qist. and Qcheese. – the amount of water taken from the source and entering the water supply system with raw materials;
Q SW is the amount of wastewater discharged into the reservoir.
For the economic assessment of water supply systems, it is necessary to consider the cost of the water used, the costs of water supply and their share in the cost of production, the environmental damage caused to the environment due to the discharge of contaminated wastewater, as well as the economic effect of using each of the considered schemes.
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Rice. Cost of water (C), capital investments (K), environmental damage (U) and economic effect (E) when using 1-4 water supply systems.
The general water supply scheme may vary depending on specific conditions. For example, if the water does not require purification, then treatment facilities and associated facilities are excluded from the scheme. When the source is located at higher elevations than the user facility, water can be supplied by gravity and there is no need to build pumping stations. Some systems use multiple water supplies, resulting in an increase in the number of major facilities.
Water intakes, pumping stations and water treatment facilities.
Water intake is a hydraulic structure that abstracts water from a supply source (rivers, lakes, reservoirs) for water use needs. In addition, there are water intakes used for hydropower, irrigation, etc. Water intake structures must ensure that water is present in the water pipeline
in a given quantity,
required quality,
in accordance with the water use schedule.
Facilities for collecting water from surface sources are classified according to the type of source (river, reservoir, lake, sea, etc.). Of the river ones, the most common are coastal, channel, floating, and bucket. They can be combined with first lift pumping stations.
Coastal water intake structures, used on relatively steep river banks, are a large-diameter reinforced concrete well with a front wall placed into the river. Water enters it through holes equipped with gratings, and then passes through meshes that provide mechanical purification of the water.
Run-of-river water intake structures, which are used on flat banks, have a head placed in the river bed; water flows by gravity into a coastal well, which is often combined with a first lift pumping station.
Floating water intake structures are a pontoon or barge on which pumps are installed to draw water directly from the river. Water is supplied to the shore through pipes with movable joints laid along a connecting bridge.
In bucket water intake structures, water flows from the river first into a bucket (an artificial dam) located near the shore. The bucket itself is used to sediment sediments, as well as to combat ice phenomena - slush, deep ice.
Groundwater intake is a hydraulic structure for collecting groundwater and supplying it to water supply and other water management systems. The choice of site for groundwater intake equipment is determined by the geological and hydrogeological conditions of the area, the distance from the place of water use, etc. Structurally, such water intakes are divided into wells and shaft wells. Wells are the most versatile, technically more advanced type of water intake and are used for centralized water supply. They have greater productivity and most fully comply with sanitary requirements. The depth of the wells can reach 800m. The flow rate can reach 50 l/s or more. The walls of wells in unstable rocks are reinforced with casing pipes, which fit one into the other and, within the boundaries of the aquifer, end with a filter made of porous concrete, gravel, ceramics, and metal mesh. Submersible pumps are used to lift water. Often, water intake wells are equipped with water towers, which regulate the pressure and water losses in the water supply network. The service life of wells is 10-15, sometimes up to 30 years.
Water intake the structures are designed to collect water from a source and roughly purify it, mainly from floating objects.
Pumping stationsPumping stations I, II and other rises serve to raise water. Lift station 1 usually supplies water to the treatment plant, lift station P supplies water to the water control tank. Their necessity is determined by the terrain and the length of water transportation. They are equipped with pumps, usually electrically driven, and control, warning and control equipment. Many pumping stations are remote controlled and fully automated.
Water treatment plants process natural water to give it qualities that meet user requirements. If the water in the source meets the consumer’s requirements, then there is no need for treatment facilities.
Water from surface sources, as a rule, is not suitable for drinking due to significant turbidity, color and higher bacterial content than is acceptable for drinking water. Therefore, before water is supplied to the water supply system at treatment facilities, it is clarified (suspended and colloidal impurities are removed), color is removed and disinfected (freed from pathogenic bacteria), softened, etc.
Purified water is supplied to the water supply facility via water pipelines and spread throughout its territory with the help water supply network.
Water supply network
The water supply network is a set of water supply lines (pipelines) for supplying water to places of water use and is the main element of the water supply system.
A water supply network laid outside the boundaries of structures is called external. The so-called house branches (pipes) are connected to the water supply network line, through which water is supplied to individual structures.
The houses are equipped internal water supply networks.
For water supply network equipment it is used water pipes. The choice of pipes depends on the required pressure in the water supply network, the nature of the soil, the installation method and economic factors. For underground installation, the most common are cast iron, asbestos-cement and steel pipes; reinforced concrete and plastic are also applicable. The depth of pipe laying depends on the level of soil freezing, water temperature and operating mode (in Ukraine about 1.5-2 m). The maximum depth of pipe laying is determined by the need to preserve pipes from destruction as a result of transport loads.
Water supply networks are equipped shut-off valves– dampers and valves for shutting off individual sections of the network, water dispensing equipment, fire hydrants, and sometimes street standpipes. Hydrants and dampers are usually installed in special prefabricated or brick wells covered with metal hatches.
According to technical conditions, the water pressure in the water supply network of populated areas should not exceed 6 atm. To supply water to multi-storey buildings additionally equip local pumping stations.
The network may be annular(consisting of separate adjacent closed loops-rings that can be turned off in case of an emergency) and branched (dead-end), in which, in the event of an accident in any section, the water supply to all sections of the network located behind the damage is stopped. Therefore, branched networks can only be installed in cases where interruptions in water consumption are acceptable.
The width of the water supply network route must be at least 40 m on both sides of the axis when laying water pipelines in an undeveloped area and 10 m in a built-up area.
In places where there is a forced intersection of water supply and sewer networks in a populated area, the water supply system is designed higher than the sewer line. The vertical distance between them is at least 0.4 m.
When laying water pipes in parallel at the same level as sewer pipes, the distance between the pipelines must be at least 1.5 m if the diameter of the water pipes is no more than 200 mm and at least 3 m if the diameter of the water pipes is more than 200 mm.
When laying water pipes in parallel below sewer pipes, the distance between the walls of pipelines in filter soils must be at least 5 m. Laying sewer pipes above water pipes should not be allowed in places where subsidence and accidents of water supply networks are possible due to high groundwater levels, laying the network along moss roofs , V seismic areas etc.
It is not permitted to locate cesspools and other similar objects at a distance of less than 20 m from water supply networks.
To regulate the pressure and flow of water, create its reserve and align the operating schedule of pumping stations, they build water towers and reservoirs.
Water tower consists of a water tank, usually cylindrical in shape, and a supporting structure (trunk). The regulatory role of the water tower is that during times of reduced water use, excess water supplied by the pumping station accumulates in it and is consumed during times of increased water consumption. The height of the water tower (the distance from the surface of the earth to the bottom of the tank), as a rule, does not exceed 25 m, sometimes 30 m; tank capacity - from several tens of cubic meters to several thousand. Supporting structures are made mainly of steel, reinforced concrete, sometimes brick, tanks are mainly made of reinforced concrete and steel.
Water tank, unlike a water tower, does not have a supporting structure (trunk), but is installed on elevated areas of the terrain. Sometimes water tanks serve to maintain fire and emergency water supplies. Nowadays the most common tanks are made of reinforced concrete.
The capacity of the tanks should ensure uninterrupted water supply during peak hours, as well as a supply of water in case of an emergency. The walls and bottom of underground tanks must be waterproof (reinforced concrete, brick). The bottom of the tank must be above the groundwater level. If necessary, it is lowered using drainage.
Centralized water supply systems in populated areas are divided into three categories based on the degree of reliability of water supply, depending on the population size:
I - more than 50 thousand people,
II -50-0.5 thousand people,
III - less than 0.5 thousand people.
notes on combat training fire department
Classification of water supply systems.
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METHODOLOGICAL PLAN
conducting classes with a group of fire department duty guards on Firefighting equipment.
Topic: Classification of water supply systems. Type of lesson: class-group. Allotted time: 90 minutes.
Purpose of the lesson: consolidation and improvement of personal knowledge on the topic: Classification of water supply systems.
1.Literature used during the lesson:
Textbook: “Fire fighting equipment” V.V. Terebnev. Book No. 1.
Order No. 630.
A water supply system is a complex of engineering structures designed to collect water from a water source, purify it, store it and supply it to places of consumption.
The purpose of fire water supply is to ensure the supply of the required volumes of water under the required pressure during the standard fire extinguishing time, provided that the operation of the entire complex of water supply structures is sufficiently reliable. The main regulatory requirements for water supply are set out in SNiP 2.04.02 - 84 * and SNiP 2.04.01 - 85 *"Water supply. External networks and structures." "Internal water supply and sewerage of buildings."
Water supply systems are classified according to a number of criteria.
1.By reliability of water supply. (they are divided into three categories).
2.By type of serviced object. (water supply systems are divided into urban, settlement, as well as industrial, agricultural, railway, etc.).
3.By type of natural sources used. There are water pipelines that take water from surface sources (rivers, reservoirs, lakes, seas) and underground (artesian, spring). There are also mixed supply water pipes.
4.By water supply method. Water pipelines can be pressurized with mechanical water supply by pumps and gravity-flow when the water source is located at a height that ensures a natural supply of water to consumers.
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5.By purpose Water supply systems are divided into domestic and drinking, industrial, fire-fighting and combined. The latter are usually arranged in populated areas.
If water consumption is high, enterprises can have independent water supply systems to meet their drinking, industrial and fire-fighting needs.
In this case, fire-fighting and industrial water pipelines are usually constructed. The combination of a service water supply with a fire-fighting one and not with a production one is explained by the fact that the industrial water supply network is usually less extensive and does not cover all the volumes of the enterprise.
In addition, for some production processes, water must be supplied at a certain pressure, which will change when extinguishing a fire. And this can lead either to an increase in water consumption, which is not economically feasible, or to a breakdown of production equipment.
A water pipeline or water supply system is a complex that includes various engineering structures: the source of water intake itself, pumping units or stations, pipelines through which water moves to consumers, reservoirs for various purposes, mainly storage type, as well as water treatment plants. That is, this is a huge complex that performs the functions of water delivery. However, it should be noted that not all water supply networks are equipped according to this scheme. Everything will depend on operating conditions, meaning local conditions. Therefore, some elements may be missing. So, what is the classification of water supply systems?
Classification based on service
Categories of plumbing systems
There are several criteria for dividing water supply networks.
- By type of service.
- How is water used?
- And according to the purpose of the system itself.
The first category includes water supply networks that supply water to various settlements or factories. For example, a city water supply system, a village water supply supplying water to a factory or farm, railway station or a car company. That is, this is a fairly wide range of all kinds of names. And depending on the volume of water consumed, such networks can be simply huge or small local.
- For drinking water.
- For technical purposes, they are also called production networks.
- For household needs.
- Fire networks.
General classification
Attention! There are combined water supply systems from which water can be used for different purposes. For example, household and drinking water or for production and then for the fire-fighting system.
Most often, combined complexes are used in various areas of human life. Firstly, it simplifies the plumbing system itself. Secondly, it reduces its cost both during construction and installation, and during maintenance. For example, you cannot apply to a food production factory. process water, it should only be drinkable.
But the types of water supply systems according to their purpose are divided exactly like this. In this case, during construction, it is the criteria for using the water supply system that are taken into account.
- The drinking water system usually serves canteens, laundries, showers, restrooms and similar establishments.
- Industrial water supply is usually built only to provide water to various technical facilities. It is clear that they include any plants and factories; small consumers include car washes, small boiler houses, workshops where building materials are produced, and so on.
- It is clear that fire-fighting water pipes provide water to fire safety systems that are part of engineering networks in factories and factories.
Pumping stations with water treatment
By the way, the latter are divided into internal and external systems. Internal - this is the distribution of pipes through which water is supplied to explosive areas. This is an open system, and the wiring is laid along walls, overpasses, cornices, and so on. External - this is pipework that is laid underground. It can be high or low pressure. The high pressure in them is maintained by special pumps that are installed at the enterprise itself. Low city water supply network or water tower.
Attention! All of the above water supply systems must be provided with a so-called operational reserve. These can be containers of different sizes, installed in different places: underground, on towers, and so on.
And the third category is based on the method of serving consumers. Global water pipelines are being built to serve several facilities located at considerable distances from each other. Such networks are called inter-district or district networks. It is clear that the structure of such water pipelines is quite complex. And if along the pipe laying route there are areas with different heights relief, then care must be taken to raise the water to the required height. It is on the border of such areas that the so-called zone water pipelines are built. Their main task is to raise water, which means that pumps are installed in this place, which create excess pressure in the supply system.
These are the types of water supply found today. But it is necessary to dwell in more detail on the combined schemes.
District water pipes
United water pipelines
It is clear that often a plumbing scheme combines all of the above categories at once. Especially if there is no other source of water besides the city or district water supply. For example, a plant whose water intake is a city water supply. That is, the factory system is simultaneously a drinking water supply system, a technical system, and a fire safety system.
The scheme of the integrated complex consists of an incoming pipe that supplies water to the reservoir. And for drinking and household needs, a separate branch is allocated, which cuts into the supply pipe to the reservoir. By the way, factories rarely use ready-made containers; usually, closed or open pools are allocated for them. This is the operational reserve. That is, if for some reason there is a water supply failure in the city network, it will not flow in the taps. But in the pool for production needs it will be contained in the required quantity. From here, water will be supplied to the fire-fighting system, if necessary.
Often, even in these cases with an extensive water supply network, drinking water is supplied from reservoirs. True, strict requirements will be imposed on the quality of water in them. This is usually monitored by the factory laboratory. As practice shows, such tanks are made of metal; concrete pools are rarely used.
- Straight-through. These are the most common networks. In them, water from the consumer after its use is discharged into the sewer system. True, this option can be called low-cost.
- Consistently repeated.
- Negotiable.
Classification of internal water supply
The last two groups, on the contrary, are very economical. In them, water after use is supplied to treatment facilities, where it is purified and returned back to the process flow. True, such water cannot be used for household needs and drinking.
As you can see, the classification of water supply systems is quite broad. It contains various schemes, which are mainly divided according to the purpose of the water supply system itself. But, as mentioned above, separate networks are rarely found; most often it is a combination of several into one.
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Water supply system is a complex of engineering structures for the intake, purification and supply of water to consumers. It includes water sources, pumping stations, treatment stations, tanks, reservoirs and piping networks.
Depending on local conditions water supply Some of these facilities may be missing. In cases where the enterprise is supplied with water from the city water supply, water intake and treatment facilities are not provided.
Water supply systems They are distinguished by the type of object being serviced, by purpose and by the principle of water consumption.
By type of serviced object water supply systems They are divided into urban, village, industrial, railway, agricultural and others.
Depending on the purpose water supply systems There are the following: household and drinking, industrial (technological), fire-fighting combined.
Household drinking water water supply systems supply water to dining rooms, showers, washbasins, latrines, laundries and other water-consuming household facilities.
Production water supply systems designed to supply water for technological needs. Process water is used for heating or cooling raw materials and semi-finished products, in heat exchangers, for washing containers, premises, etc. Most of the water supplied to the enterprise is used for production purposes.
Fire protection water supply systems provide water to extinguish fires inside enterprises and on its territory.
Fire-prevention water supply is divided into internal and external. Internal water supply is installed in fire and explosive areas (machine and equipment rooms of ammonia compressor stations, crushing and sifting departments of feed flour, etc.). All connections are provided with fire-fighting equipment (hoses with fire nozzles, deluge and sprinkler installations).
External water supply on the territory of the enterprise is laid underground. It can be low or high pressure. Low water pressure is maintained by the city pumping station, water tower, second lift pumping station. High pressure is created by special stationary fire pumps. They are installed in enterprise premises.
Each water supply system provided with an operational water supply. This stock is stored in underground tanks. The amount of operational reserve is determined based on the consumption rates for fire extinguishing. The required pressure in the water supply system is created by a water tower, pneumatic installations or second lift pumps.
Water supply system, serving several large objects located at a considerable distance from each other, is called a district or regional water supply system.
Sometimes the water supply system provides water to objects located in areas of the territory with different heights. In such cases, zone water supply systems are installed. For high areas, pumps support high blood pressure, which is not needed for low-lying (boosting pumping stations).
If there are combined water supply systems water is supplied for various purposes. For example, at meat and dairy (i.e. food) industry enterprises, only drinking water is used for technological needs. This allows you to combine drinking water and industrial water supply systems into one common one. So common water supply system Can also be used for fire protection purposes. In some cases, partially integrated water supply systems are built - industrial and economic, when only drinking water is used for technological purposes, and economic and fire-fighting (in administrative and utility premises). In addition, enterprises arrange hot water systems.
All systems internal water supply They are divided according to the principle of water consumption into direct-flow, sequential-repeat and circulating.
IN direct-flow water supply systems water from points of consumption (different links technological process, washing equipment and premises, showers, toilets, etc.) are flushed into the sewer. The direct-flow system is the most common and least economical. Significant water savings are achieved by sequentially repeated and circulating system water supply
Sale and installation in a country house or cottage.
Water supply system- a complex of interconnected devices and structures that provide consumers with water in the required quantity and specified quality. The water supply system includes devices and structures for collecting water from a water supply source and transporting it; processing, storage, regulation of supply and distribution between consumers.
Water supply scheme- sequential arrangement of these structures from source to consumer, their relative location relative to each other.
Water supply systems must be designed in accordance with the requirements for the design of external networks and water supply structures, as well as other regulatory and technical recommendations and requirements for water by consumers. In this case, it is necessary to take into account local conditions, the diversity of which leads to the fact that the water supply system of any facility is unique and inimitable in its own way.
The whole variety of water supply systems encountered in practice is classified according to the following main characteristics:
- by purpose: household and drinking; fire protection; production; agricultural. The listed types of systems can be either independent or combined. Systems are combined if the requirements for water quality are the same or it is economically beneficial;
- by the nature of the natural sources used: systems receiving water from surface sources (rivers, lakes, reservoirs, seas, oceans); systems that take water from underground sources (artesian, groundwater); mixed power systems (when using various types water sources);
- on a territorial basis(coverage): local (one object) or local; group or district, serving a group of objects; off-site; on-site;
- by water supply methods: gravity (gravity); pressure (with mechanical water supply using pumps); combined;
- according to the frequency of use of consumed water(for enterprises): direct-flow (single use); with consistent use of water (two or three times); circulating (repeated use of water, carried out in a closed, semi-closed circuit or with the discharge of part of the water - blowing); combined;
- by types of objects served: urban; village; industrial; agricultural; railway, etc.;
- according to the method of delivery and distribution of water: centralized; decentralized; combined.
Water supply systems in populated areas are usually centralized. Moreover, depending on local conditions and economic feasibility, they can be separate - with their own sources of water supply for each of the zones (residential or industrial) - or combined - with a common source of water supply for both zones (Fig. 9.1).
Figure 9.1 – Water supply systems: A - centralized separate; b - centralized united; V - combined: 1 - water intake structure; 2 - pumping station NS-1; 3 - treatment facilities; 4 - clean water tanks; 5 - NS-N; 6 - water tower; 7 - water conduits; 8 - distribution water supply network; 9 - populated area; 10 - production zone.
Decentralized (local) water supply systems are built for individual remote local consumers or groups of buildings, as well as settlements planned for resettlement.
Based on reliability or the degree of security of water supply, centralized water supply systems are divided into three categories (Table 9.1).