What types of external water supply networks are there? Water supply system for urban areas
A city's water supply system is a complex of engineering structures designed to collect water from a source, treat it, store it and supply it to the consumer.
Natural sources of water supply are divided into:
1) Surface (rivers, lakes, reservoirs). Have the following characteristics:
Turbidity
Low hardness
2) Underground (groundwater, artesian springs). Their characteristics:
Transparency
High rigidity
That. underground ones are preferable, but there are few of them (small debit).
The water supply source must meet the following requirements:
1.Uninterrupted supply of quality water
2. Sufficient power (ecological balance)
3. Short distance from the object of consumption
Household and drinking needs (including watering)
Production purposes (transport, agriculture, industry)
Firefighting and property needs, plumbing (washing filters, networks, etc.)
The networks and structures of the city's water supply system with a surface source are presented in Fig. 1 A. Water enters the water intake structures 7, from where it is pumped from the first lift pumping station 2 through the first lift water pipelines 3 supplied to wastewater treatment plants 4. After purification from clean water tanks 5 it is taken up by the pumps of the second lift pumping station 6 and through water pipelines of the second rise 7 it is supplied to the external water supply network of the city 8, distributing water to individual areas and quarters of the city. Water tower 9 can be located in front, in the middle, or behind the city network. In the latter case, it is called a countertower. The city network is connected to the water tower by water conduits 10. All water pipelines are designed with at least two lines in case of an accident. The emergency water pipeline must ensure the passage of at least 70% of the city’s daily water consumption. Depending on the method of water supply, water pipelines can be injection or gravity.
The relative location of water supply system structures and their composition may be different. The water supply pumping station of the first lift can be combined with a water intake structure, and the pumping station of the second lift can be located in the same block with a clean water reservoir. The location of the system's structures is significantly influenced by the terrain. When the water supply source is located at a significant height relative to the city, water from the source is supplied without the help of pumps, i.e. by gravity. The water tower is always located on high ground. If there is a significant natural elevation near a populated area, an upland reservoir is designed instead of a water tower.
The water tower in the system performs a pressure-regulating function, i.e. it compensates for the discrepancy between the modes of water supply by pumps and its consumption by the city at certain hours of the day, accumulating excess water supplied at some hours and making up for its shortage at others. In this case, the water consumption for extinguishing one internal and one external fire for 10 minutes is stored in the tower tank constantly. If there is no water tower in the city’s water supply system, then during hours of minimum water consumption, water is supplied to the city by pumps of lower capacity located at the second lift pumping station.
The networks and structures of the city's water supply system with an underground source are shown in Fig. 1 b. The scheme is significantly simplified compared to the city water supply scheme with a surface source, since there is no expensive water purification complex, since groundwater not only has excellent taste, but also does not require deep purification. In some cases, local installations may be used to remove iron or remove excess salts, as well as to disinfect water. They are installed at the pumping station. Therefore, according to the scheme (see Fig. 1 b), water from water wells 11 enters the collection tank 12, and then pumps of the pumping station 6 supplied to the city water supply network 8. In some cases, the water supply to the city can be two-way.
Rice. 1 – Networks and structures of the city water supply system
1 – water intake structures; 2 – first lift pumping station;
3 - water conduits of the first rise; 4 – treatment facilities; 5 – clean water tank; 6 – pumping station of the second lift; 7 – water conduits of the second rise; 8 – external water supply network of the city; 9 – water tower; 10 – water conduits connecting the water tower to the city network; 11 – water intake wells; 12 collection tank.
Comparative characteristics city water supply systems with surface and ground sources summarizes the main advantages and disadvantages of the systems described above.
The city water supply network consists of main and distribution pipelines. The mains serve to supply water in transit to certain areas of the city and to supply water to adjacent areas. Distribution networks supply water directly to consumers and fire hydrants. Distribution networks are laid along all streets along buildings or between them.
In the continuous development of streets and avenues, the internal water supply systems of buildings are connected directly to the street water supply network using house branches. If the buildings are located inside the block, direct connection of house branches to street networks is impossible, so they lay a yard water supply network, from which they arrange inputs into the buildings.
In modern mass construction, the development of cities and populated areas is carried out by creating large neighborhoods and microdistricts, including residential buildings, cultural institutions, sports grounds and green spaces.
A new concept is emerging - a microdistrict (intra-block) water supply network, consisting of main and distribution pipelines.
Rice. 1.3.1. Scheme of the intra-block water supply network: / -street water supply network; 2 - intra-block network with inputs to each building; 3 - partial laying of pipelines through buildings in transit; 4 - wells on the external network; 5 - external watering taps on the internal network; 6 - wells on the intra-block network.
To supply water to microdistricts, a microdistrict network is provided (Fig. 1.3.2.a), consisting of an inlet connecting the external water supply network to the building of a central heating point (CHS), and a quarterly network transporting water from the central heating point to groups of buildings or individual houses. With significant block sizes, the microdistrict network also provides firefighting needs, so fire hydrants are placed on it at a distance of no more than 150 m from each other in places convenient for fire trucks to access.
Neighborhood networks are laid along intra-block passages parallel to buildings at a distance of at least 5-10 m, depending on the material of the pipes. Water supply networks are placed at a distance of at least 1.5 m from the heating network, sewer pipelines with a water supply network diameter of up to 200 mm and at least 3 m with a larger diameter: at a distance of 1 m from low and medium pressure gas pipelines (up to 0.3 MPa) and power cables; 0.5 m - from communication cables. When laying pipelines with a diameter of 300 mm in parallel, the distance between the outer surface of the pipes must be at least 0.7 m, which will ensure the possibility of installing and repairing pipes in the event of an accident on one of them. To reduce construction costs, it is advisable to lay a water supply system in the same trench with heating networks and hot water supply (Fig. 1.3.2 c ), using basements and technical undergrounds of buildings for the transit laying of pipelines.
In large microdistricts with a significant number of communications, it is advisable to use through or semi-through channels. This also allows you to reduce the cost of repair and maintenance of utility lines. When laying pipes in tunnels, the distance from the pipe wall to the internal surfaces of the tunnel and other pipelines is taken to be at least 200 mm.
Currently, non-passage channels and through tunnels are widely used (Fig. 1.3.2 d). Channels are laid from the central heating point to buildings so that the minimum distance between the walls of the channel and the building is at least 5.0 m; to tree trunks - at least 2.0 m.
Rice. 1.3.2. Microdistrict water supply: a - power supply to buildings through a central heating point; b - individual connection of buildings; c - laying pipelines in one trench; d - passage tunnel: 1 - quarterly network; 2 - central heating point; 3 - external distribution network; 4 - well with hydrant; 5 - individual input; b - street water supply network; 7 - sanding; 8 - hot water circulation pipeline; 9 - hot water supply pipeline; 10 - cold water supply pipeline; 11 - heating pipelines; 12 - pipe filter; 13 - communication cables; 14 - power electrical cables; 15 - gas pipeline
The depth of pipes (to the bottom of the pipe) is taken to be 0.5 m greater than the calculated freezing depth, taking into account external loads from transport and the conditions of intersection with other underground utilities. To prevent heating of water in the summer, the laying depth is taken to be at least 0.5 m from the top of the pipes. When crossing with other pipelines, this distance must be at least 0.2 m, when crossing cables - 0.5 m.
External water supply networks laid on the territory of industrial enterprises usually supply water for external fire extinguishing, so hydrants are installed on them every 150 m.
External water supply networks are one of the main components of the water supply system, the sources of which are: 1) open natural and artificial reservoirs - rivers, reservoirs and lakes; 2) groundwater - springs, wells.
The location of water supply lines depends on the following factors taken into account during the design of engineering structures:
Terrain and obstacles: rivers, railway tracks, highways, etc.;
Green spaces;
Layout of a residential area;
Layout of objects to which networks are connected.
Types of external water supply networks
Branched
The complex of the main line and branches, which are dead-end sections, is considered a branched scheme of an external water supply network. Water along dead-end lines moves in only one direction. Being the shortest along the length of pipelines, dead-end sections are considered the least reliable in terms of uninterrupted supply of water to consumers.
The main disadvantage of an extensive water supply scheme: an accident in one of the network sections will deprive all consumers located behind the emergency section of water.
In large populated areas, a branched scheme is not used, since long interruptions in water supply are not allowed. In dacha settlements, an extensive water supply scheme can be designed, provided that consumers have backup tanks installed in case of lack of water.
Ring
A water supply network that does not have dead-end branches is called a ring network. The ring water supply scheme assumes that all sections are connected to each other and are closed to each other.
Combined
The complex of ring and dead-end sections is a combined water supply network. Ring and combined schemes of water supply networks are considered more reliable in operation, since turning off an emergency section does not affect the water supply to other consumers. In addition, in a ring water supply network, water constantly circulates through the pipes without stagnating.
Plumbing equipment for external water supply systems
- Pumping stations.
- Treatment plants.
- Shut-off and control valves.
- Control and measuring devices.
- Manholes and other equipment.
"Types of external water supply networks and equipment for water supply systems", BC "POISK", tell friends: May 21st, 2017
Water supply, in other words, water supply networks are a closed system consisting of many elements and structures designed to provide premises with water. Moreover, the water supply system itself consists of both external and internal networks. What is included in the external water supply networks, as well as the characteristics and operating features of the components will be disclosed in this article.
Consumables for external networks largely coincide with those for internal networks, although they are required in larger volumes. Pipelines are a key component of external networks. The material of modern pipelines is represented by a diverse range, from classic steel to modern polypropylene and polyethylene structures. To increase pressure in external networks, pumping stations are used, since pumping in pipes is carried out under the required pressure from the source to consumers.
Shut-off valves and inspection wells are also placed on the pipeline line. Most modern systems use water treatment stations in external networks. Such stations carry out additional purification of water, increasing its quality and making it suitable for drinking. External networks may include water intake and water intake structures. The former are required for collecting water from a source, the latter for storing water.
The purpose of external networks is different. The most common purpose is the transmission of drinking water, that is, household water. There is also an external one, intended exclusively for extinguishing water. Industrial and technological external networks are designed for pumping non-potable water for technological needs. Irrigation and watering systems are needed for agricultural needs and care for ornamental plants. There are also combined systems that combine several of the above purposes.
What will be required before starting work?
At the design stage, it is necessary to take into account many standards in accordance with the water supply standards - GOST and SNiP standards related to water supply.
There is a standard for separate distances between parts of external water supply networks and landscape elements. For example, the distance from the sewerage system to the water supply system must be at least a meter, and the distance from the water supply/sewerage pipes to the border of the roadway must be at least two meters.
In addition to the permit and the project, it will be necessary to obtain certificates from technical supervision for compliance with the requirements for excavation and hidden work.
In addition, it is important to ensure that the quality of consumables meets existing standards. Only the use of high-quality materials can ensure uninterrupted operation of external water supply networks.
The initial stage of installing external water supply networks
After the task for designing a water supply system has been drawn up and all preliminary operations have been carried out, the construction of water supply networks in the planned area begins. The first step is excavation work, which consists of digging trenches for the pipeline. Next, the bottom of the trenches is filled with quartz sand, which will ensure a safe location of the pipeline pipes. At the third stage, pipeline pipes are installed. The trench is dug from the water source 50 centimeters below the freezing depth
There are several ways in which water supply and sewerage can be laid - above ground and underground. Aboveground is carried out on overpasses and supports, and underground can be trench or trenchless. The trench underground laying system may involve the use of special equipment or be done manually. Trenchless underground installation is installed only using HDD (horizontal directional drilling) units. In cases where it is not possible to install a pipeline using a trench method, in some areas external networks are installed using gas pumping units and the formation puncture method.
Therefore, recently, in addition to the trench method, a trenchless method has also been used, which includes laying cases. The following advantages can be identified in trenchless installation: economically less expensive, more automated, low cost, and more environmentally friendly. This type of installation is carried out by installing cases under the pipeline. In this case, the diameter of the case for the water supply must exceed the diameter of the pipes themselves.
The final stage of installation of external water supply networks
Returning to the stages of installation of external networks, it should be noted that wells, shut-off and control valves, distribution columns, and fire hydrants are then installed. It is important to note that quartz sand is used not only to create a base for placing pipes in trenches, but also to compact pipes in the future. For this purpose, its layer-by-layer backfill is used. Thus, it is established that the external fire water supply system is the same as all other external networks.
After the main external networks and water supply structures have been installed, restoration work takes place at the installation site, which may be accompanied by the introduction of landscaping elements into the landscape area. Next, acts of hidden work are signed. And after connecting the external water supply networks to the plumbing systems of the premises, all documentation of an executive and technical nature is finalized.
Testing of external water supply networks
After installation of external networks, the water supply system is always tested for strength and tightness to ensure the quality of the work performed and the suitability of the water supply system for use. In this case, a preliminary test is carried out before installing shut-off valves and backfilling the dug trenches. However, the final test is carried out only after all work has been completed. So, the strength calculation of a water pipeline is carried out by testing it with internal pressure. The test is considered successfully completed when there is no rupture of the pipes, no damage or leakage at the joints.
Additional Information
Additionally, several points need to be highlighted. There is a frequently asked question “what should be the distance between the water supply and sewerage inputs,” in other words, between the input and output. As a rule, the water supply inlet is located either to the left or to the right of the sewer outlet. The distance between them should be more than one and a half meters with an input diameter of up to 200 mm, and more than three meters with a diameter of more than 200 mm.
Many representatives of the private housing sector regularly faced written notices about unauthorized connections to the water supply.
You should be aware that the fine for an unauthorized connection to a water supply system is over 25 thousand rubles, and the violator is disconnected from the network.
To avoid this, it is recommended to use only legal connection methods. To officially connect to the water supply, it is necessary to agree on a project plan for external networks and obtain permission from the relevant authorities, as described above.
Questions also arise regarding existing water supply schemes. There are several types of wiring. The main ones are the roundabout and the dead-end. The ring is distinguished by an uninterrupted water supply. With such wiring, much more consumables are required than when installing dead-end wiring. The latter supplies small enterprises and is also activated in case of accidents on the roundabout.
In general, this is all you need to know about external water supply networks. In this article, you can familiarize yourself in detail not only with the existing features of installing external networks, but also obtain additional information on current issues. In the field of laying external water supply networks, the most interesting are new methods of trenchless installation. With their speedy implementation and widespread use, it will be possible to install and repair water pipelines without blocking roads and increasing surface clutter.
Water supply and sewerage for construction projects is the most necessary invention of man.
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Man is designed in such a way that he cannot do without water. At all times, people settled in places near rivers and dug wells to gain access to this vital liquid. Subsequently, water supply systems began to be designed, which are necessary for human life, rest and work. These systems must ensure high-quality uninterrupted supply of water in the required quantities and at any time, and comply with the joint venture Water supply external networks and structures.
Simultaneously with water supply systems, sewerage systems for receiving and processing water and human waste also progressed.
Rules for laying communications
In order for people to live comfortably, household amenities must be located in the room where they are located. Therefore, in addition to laying pipes inside the building, the facility must be connected to external communication networks. As in any locality where construction of a facility is taking place, a prerequisite for the provision of water and sewerage is SNiP Water supply external networks and structures:
- permission and design for this type of construction work with the laying of external communications and water supply entry points into the house for connection to the internal plumbing network, as well as the sewerage outlet point connected to the cleaning system;
- compliance with the requirements for excavation work, control over hidden work and execution of technical inspection reports;
- compliance with requirements for network materials and their quality; networks must guarantee trouble-free operation of the water supply and sewerage systems; correcting faults will lead to additional costs for the developer.
Such serious requirements are determined by:
- compliance with high-quality installation of networks and subsequent safe operation;
- financial savings and trouble-free operation of the external water supply and sanitation network;
- protection from damage to other communications laid in the ground where network installation work is being carried out;
- the terms of environmental laws that are aimed at protecting groundwater;
- compliance with sanitary standards that do not allow contamination of the areas where the construction project is located;
- terms of building regulations.
Main stages of work
The general stages of installing external engineering networks for water supply and waste water removal after registration of project documentation and permits include:
- Ground work for laying pipes.
- Construction of a base for laying pipes, filling the bottom with sand.
- Installation of pipelines in trenches.
- Installation of pipes by piercing the soil and horizontal drilling if it is impossible to dig a trench (under the road).
- Installation of reinforced concrete, brick wells, chambers.
- Installation of control and shut-off valves, fire hydrants and water pumps.
- Backfilling the network with safe material, sand with compaction.
- Restoration of the territory in the area of construction work, landscaping.
- Registration of work reports at all stages.
- Preparation and connection to the central communications network or to the internal plumbing in the house for individual water supply and sanitation.
- Preparation of a package of technical documentation and delivery of the construction project.
External water supply networks
Water supply systems can be centralized in the form of an extensive city network, or autonomous if there is no central network for supplying water to houses. They must meet the requirements of SNiP External water supply networks.
Central networks consist of the following elements:
- water intake (reservoir, lake, river, well);
- stationary complex;
- pumping station to provide the required pressure;
- wells, connection points and shut-off valves.
Types of autonomous water supply
If there is no central water supply network nearby and there is no connection to it, then water supply can be provided as follows. Drinking water can be supplied in containers for cooking and drinking. This is a temporary transitional option until a permanent, reliable water supply to the building is established.
You need to know that there is water everywhere in the earth. This does not depend on the location of your place. The only question is the depth of the water layers and its quality. To get water and raise it to the surface, you need to build a well or a deep well.
External systems - water supply and sewerage
There are many types of sewer networks used to remove wastewater from structures and buildings. When developing a project for a construction project, it is necessary to take into account SNiP Water supply and sewerage external networks:
- purpose of the object: economic facility or residential building;
- seasonal, episodic, continuous operation time of the house and sewer networks;
- system load, waste volume, number of plumbing fixtures installed in the house, number of people living;
- the terrain where the building is located;
- system cost;
- system design together with the outlet pipeline;
- wastewater treatment, reception and disposal system;
- ratio of performance, quality and price;
- equipment, components and materials;
- quality of wastewater treatment;
- service and guarantee of reliable operation.
Types of sewerage receiving equipment
For occasional or seasonal use in the house, it is often enough to install a dry closet. But this system is not able to ensure the removal of wastewater from the laundry, shower and kitchen. To do this, install different containers to collect wastewater. The advantages of such receivers include mobility, compactness and low-cost maintenance.
For long-term stays in the building, external sewage systems are installed - a cesspool, a waste tank, a septic tank, and a deep cleaning system.
Cesspool for sewage and waste
The previously used type of external sewerage in the form of a cesspool was a good device where construction of buildings was carried out and there was no central sewerage system. Today it is difficult to obtain permission to connect a new house to the existing sewerage system in a populated area. Therefore, a device such as a cesspool worked for a long time due to its simple design, cheap maintenance and long-term operation.
In the modern period, a cesspool is sometimes built outside the city, near houses where people live for the season. With the emergence of a large number of plumbing fixtures in homes and significant water consumption for various needs, the cesspool can no longer cope and needs frequent cleaning.
An alternative to pits is septic tanks
These are autonomous treatment plants and structures, both industrially manufactured and home-made.
The following types of septic tanks have become the most popular:
- Cleansing look. They make it possible to collect and process wastewater, settling it in chambers with the help of bacteria.
- Cumulative. They are made in the form of ordinary large containers of different volumes, accumulating and storing wastewater until it is removed by special machines.
Homemade septic tanks are a system of several chambers in which solid waste settles. Depending on the number of chambers, they are two or three chamber. The containers are made of concrete rings, bricks or monolithic. A mandatory requirement for septic tanks is tightness to prevent microorganisms from entering the soil and the external environment.
Construction of septic tanks
To install a septic tank yourself, you need to consider the following factors:
- type of soil in the area;
- the shortest distance from the water intake on clay soils and heavy soils is at least 30 meters;
- on sandy loam and sandy soils, the distance from the water intake is at least 60 meters.
The work is carried out in the following order:
- Digging a pit of the required size.
- Sprinkling the bottom with layers of crushed stone and sand.
- Laying reinforcing mesh, pouring concrete.
- Arrangement of receiving chambers, formwork, pouring walls with reinforcement, installation of concrete rings.
- Sealing seams and joints.
- Connecting pipes to the septic tank from an external sewer.
- Arrangement of a locking device for cameras.
Often a septic tank is equipped with a wastewater treatment device; in settling tanks only partial treatment occurs. A filtration system consisting of drainage pipelines at a slope is installed. Water through these pipes from the septic tank is distributed through the filter, and penetrating through the soil, it is purified.
Industrial cleaning
Such systems are manufactured in such a way that they are easy to install, they are reliable in operation and do not pose a danger to the external environment. The industry produces a large number of different designs, depending on the degree of purification, cost and other characteristics. Typically, companies install and configure their products themselves, and also provide a warranty on the equipment.
In areas where groundwater is shallow, it is impossible to install conventional septic tanks. Otherwise, you will have to frequently pump out the drains with a special machine. In such a situation, the best option would be to install a deep cleaning system.
Such stations are highly efficient compared to a septic tank and are used for large buildings. This equipment requires a continuous supply of electrical energy for normal functioning of high-quality cleaning. The stations make it possible to purify wastewater by 98%, use reliable membranes and comply with SNiP Water supply and sewerage.
A good indicator of wastewater treatment equipment is that the system remains without wastewater for a short period of time. With a new supply, the process of biochemical reactions is restored for deep purification of wastewater coming from the general sewer system.
List of pipes and additional elements
Conclusion
In the regulatory documents you can find all the necessary provisions on external and internal communications and pipelines. This document makes it possible to prevent various errors during the construction of important facilities.