Sewer wells: full classification and examples of arrangement
One of the main elements of a modern drainage system is a sewer well. We often meet hatches of these structures, even if we just walk along the streets of the city. But also in the autonomous sewer system, which a private owner equips on his site, wells are also used.
We suggest that you familiarize yourself with the classification of wells presented by us for sewage systems. Their division into types was carried out according to the functional purpose and the material used in the manufacture. The article will help to understand the varieties and choose the appropriate option.
Our detailed information on the types and operational features of wells, which are a mandatory component of the sewage system, is supplemented by diagrams, video and photos for visual perception.
The content of the article:
Why do we need sewer wells?
Sewerage is one of the essential attributes of civilized life. And it doesn’t matter if it is about the life of a large industrial city or an individual family living in a country cottage. Through this communication, waste is discharged, the disposal of which in its absence would be a big problem.
Sewer systems, like any other structures, need maintenance. Their condition must be monitored: maintain operational functions, periodically performing ongoing repairs.
If the system becomes clogged, emergency intervention may be necessary. To ensure all these processes are needed sewer wells.
If it seems to you that the hatches, by which we determine the presence of a well on the street, are randomly located, then this is not so. There is SNiP “Sewerage.External networks and structures ”, which defines the standards regarding the number and location of wells, their types, arrangement technology, as well as the requirements for the maintenance of sewer systems.
Classification of sewage wells
Structures related to sewer wells according to technical terminology are divided into several varieties.
The division is carried out depending on what classification features we will use. For example, you can divide the wells according to the material of manufacture, according to the purpose or by the method of their construction.
There are the following classification signs and the corresponding types of modern sewer wells. The first is made on the environment, the transportation of which is carried out by the sewer system.
Drainage networks, on which sewer wells are installed, are designed to move sewage of various composition and degree of aggressiveness, these are:
- Household. These include waters that have changed composition as a result of mixing with waste and garbage. Depending on the constituent contaminants are divided into household and fecal.
- Industrial. These include waters that have changed the mechanical and chemical composition as a result of contamination with industrial waste.
- Atmospheric.These include waters formed as a result of active melting of winter precipitation, flood and rain water.
In addition to the listed types of wastewater, the sewage system receives flows collected by the drainage system, the task of which is to drain the territory or drain groundwater from underground building structures.
Wells of sewer systems are subdivided according to the material of manufacture into:
- Brick. Once, brick was a frequently used material for the manufacture of wells, but over time, brick structures become less and less.
- Concrete Concrete structures - today it is a traditional version of the material for the sewer well.
- Plastic Obviously, compositions with a polymer base are the material of the future, it is he who will someday replace both brick and concrete.
Plastic or composite prefabricated well structures attract lightness, easy to install. Pleased with resistance to chemical influences during prolonged contact with aggressive environments. They tolerate sharp and smooth temperature fluctuations, do not pass or absorb water at all.
Sewerage systems are divided into alloyed and exported. The former move wastewater to treatment plants, facilities or discharge fields. The second only collects effluents for subsequent pumping and removal. Wells included in both types of systems perform both identical and different functions.
According to their functional responsibilities, they are divided into:
- Cumulative. Used for the accumulation of effluents for subsequent extraction and removal. Naturally, they are being constructed in export sewer networks.
- Collector. Designed to collect wastewater from several sewer branches and to direct them to a storage tank, to a sewage treatment plant or to unloading fields. They are arranged both in alloyed and in export branched networks.
- Filtering. They are used to dispose of the liquid fraction of effluents in a natural way. They play the role of compact wastewater treatment plants, transporting freed from environmental pollution into the soil or into water bodies.Accompanied exclusively by the alloyed type of sewage.
- Lookouts. They are being built on collector sections longer than 50 m, as well as at all turning points and nodal connections of highways. Needed to monitor the operation of the sewer system, for periodic cleaning and repair operations. They are arranged in both types of sewers.
- Overflow. They are satisfied in areas with sharp high-altitude drops. The reasons for the construction include ensuring in-depth release into the water body and the need for braking effluents on sections of the pipeline with a large slope. May be present in both export and flooded sewers.
The classification of manholes is much more complicated. We will talk about this a little lower, and now we will consider different types of wells in more detail.
Storage and filter type
Cumulative is a large sewer well, into which all sewage from a private house flows. The required size of this building is determined by the number of people living in the house and the amount of water that they use.
Typically, a storage well is placed in the lowest part of the site. This provides the desired angle of inclination, allowing the drains to move spontaneously under the action of gravity along sewer pipe.
This structure is often made of plastered reinforced concrete rings. For the same purpose, you can use a factory-made plastic container.
The plastic well is convenient both in installation, and in operation. Of course, while installing it, you also need to have some knowledge and skills, but still its installation is easier than working with a concrete analog.A concrete structure should not have gaps or crevices, otherwise liquid waste may leak through leaky seams, spreading an unpleasant odor.
Another point for the reception and partial disposal of effluents is filter well. Sewage also rushes into it by gravity, but it doesn’t stay in the sealed tank until it is transported, but it moves to the underlying soil, passing through a kind of filtration.
Filtration wells are constructed without a bottom in the usual sense. At its base, a multi-layered, multi-stage natural filter of sand and gravel of various fractions is arranged.
For the manufacture of filtering structures, brickwork or concrete rings are also most often used, but their diameter, as a rule, is smaller. The design of this well is different in that it lacks a bottom. The structure itself is covered with either coarse sand or gravel.
Functions and features of manholes
In order to monitor the condition of the sewer system and timely eliminate the problems that arise in it, it is necessary viewing sewer wells. Therefore, they are placed in places where system failure is most likely.
They should be present in such places:
- where the slope of the pipeline or its diameter changes, which determines the rate of movement of wastewater and the width of the stream;
- where the flow changes direction;
- where side branches are connected to the main pipeline;
- where you need to monitor, despite the fact that special prerequisites for breakdowns are not observed.
Observation structures are usually placed in a straight line, observing a distance between the wells of 15 meters. If we are talking about a private house, then the first viewing well should be at a distance of not less than 3 m, but not further than 12 meters from the house.
The main function of these wells is still not the elimination of the resulting clogging, but its prevention. When the sewage system becomes clogged, a return flow of sewage is possible. To prevent this from happening, experts recommend that a check valve be provided in the first viewing structure, which, in the event of clogging, will close the exhaust pipe.
Viewing wells are also divided into several subspecies.
Changing the direction of flow:
- Nodal They are installed above the unit, that is, in the place where the side branches are connected to the main pipeline. At the same time, there can not be more than one incoming and three outgoing pipes in the construction tray.
- Rotary. Such structures are located above the place where the pipeline turns. There is a rule according to which the angle of rotation should not be less than 90 degrees.
The rotation should be performed with smooth rounding, the radius of which can be from one to five diameters of the incoming pipe.
Direct-flow structures in places where there is no change in the direction of flow and branches:
- Control. These wells are installed in places where sewage is discharged into the sewer. With their help, the quality of the cleaning performed is monitored.
- Flushing. They are placed at the beginning of the network for washing it.
- Linear They are used for periodic preventive inspection of networks and for their cleaning.
Sometimes with the help of one structure, not one, but several tasks can be solved at once. Despite the abundance of functions that are assigned to these structures, all observation wells are arranged approximately the same.
They have manhole cover, inlet neck, well shaft, its working chamber and bottom - outgoing and incoming pipelines are specially connected here to facilitate the diagnostic procedure.
Reinforced concrete is usually the material for manufacturing inspection wells, but recently, plastic containers are in great demand. Installation of such structures is carried out in the ground. They become the connecting parts of the sewer pipeline.
If this viewing structure is done in summer cottages, then some craftsmen adapt sewer pipes with a large diameter for such purposes. Typically, such a design copes with the tasks for the sake of which it was built.
To maintain drainage and storm sewer systems, inspection wells are also installed, the types and features of the installation of which you can read in another popular article our site.
Features of differential species
The main function of the sewer wells of the differential type is to change in height and adjust the speed of the flow. These structures can have a rather diverse design.
Sewer overflow wells are installed there:
- where the depth of the inlet pipeline decreases;
- where there is a risk of a sharp change in the flow velocity;
- where there is a highway intersection of underground structures;
- where this well is the last along the path of the movement of effluents before dumping them into a reservoir; Such a structure may have a flooded outlet.
Given the diverse tasks that are assigned to these structures, the internal structure of these sewer wells can have different design solutions.
According to the type of differences, the designs are divided into:
- tubular, at the base of which a vertical pipe is necessarily present;
- cascade - multi-stage mine-type structures for lowering the flow rate;
- with a practical profile, having a water sink in the downstream;
- equipped with a water-drain wall;
- fast currents are short sections of the pipeline that are installed under a significant slope.
The last of these wells can also be used in autonomous sewage, in the case when the volume of runoff is not large enough to ensure the cleaning of sewer pipes.
There is one more type of overflow wells, which are installed on those sections of the sewer network into which fire hazardous or explosive substances can enter or form.
Such wells are equipped with water locks. The specificity of such structures is that the flow level here changes in the opposite direction: instead of lowering, it rises.
This effect is created using a special camera in which the preliminary accumulation of effluents occurs. In case of emergency, the water valve will prevent the fire from spreading.
What are these wells made of?
Most of our fellow citizens are sure that all sewer wells made of concrete. And they are almost right.
Typically, reinforced concrete rings are used to construct wells that are located on the lines of the central city sewer system. Only occasionally cubes or slabs of the same concrete are used for the same purpose.
Modern commodity producers are actively mastering the production of polymer products, which in all respects are superior to reinforced concrete analogues. Gradually, although not as fast as we would like, they conquer the Russian market. But while polymer structures are limited in application, concrete structures will still retain their leadership positions for some time.
Reinforced Concrete Wells
When the norms and rules were created, which to this day regulate the procedure for creating sewer networks, no one heard of high-strength polymers.
And to date, sewer cleaning can be done manually. One worker descends into the well to push the wire to the side of the clogging that has occurred, while his assistants at the top rotate its second end.
Wells for all types of sewers vary in depth and in size. According to these characteristics, they are divided into serviced and inspection types. The first require immersion in the staff. The health and technical condition of the second can be monitored from the surface.
The standard sizes of the serviced wells were calculated in such a way that a person could not only fit in it, but also work. The size of the structure of 700 mm is minimal. A series of standard sizes continue 1000,1250,1500 and 2000 mm. These standards have been preserved in our time.
Taking into account these normative sizes, round plates are also produced, which are used as a base or upper floor with a hole for the hatch with a diameter of 700 mm. Thus, the components of a standard reinforced concrete well are:
- base or bottom in the form of a circle or rectangle;
- rings making up the shaft;
- upper ceiling with a round hole for the hatch;
- polymer or cast iron manhole cover.
The round shape is explained by the fact that a structure with just such a geometry best exerts resistance to the surrounding soil.
The manufacturer does not know in advance where and how they will be used. reinforced concrete elements, therefore, they are made in a standardized, even form, and are provided only with embedded parts - hinges, which are supposed to be used in the installation process.
In order to get the pipeline into the well, in the lower reinforced concrete ring you need to punch a hole, and on the bottom plate mount the tray of the shape you need. This design forms the basis of manholes and even wells, in which the device can be somewhat modernized taking into account the design features of a particular model.
The height of the well depends on the number of standard and additional rings that are used in the process of its construction. In order for the subsequent ring to be installed as tightly as possible to the previous one, it is necessary to remove the extra mounting loops. All cracks in the structure should be covered with cement.
Since such measures are still not able to provide a normal level of waterproofing, sewage from a reinforced concrete well pollutes the soil, while groundwater, on the contrary, penetrates the well and contributes to its overflow.
Polymeric products for inspection
Wells made of modern polymers have provided sewer designers with a whole new level of freedom.
The technical revolution, due to which mobile complexes arose, arrived in a timely manner. With their help, the maintenance of sewer pipelines can be carried out without the participation of people who are lowered into the wells.
And this means that the size of the wells can not be customized to fit an adult man. You can replace a bulky structure with a compact device up to 300 mm in diameter. Another advantage of polymer products is their low weight. The size of such a well can be precisely tailored to the needs of a particular sewer network.
Modern polymer wells can be classified according to various criteria. Well shafts may differ in the material from which they are made. They can be smooth, corrugated and combined.
In turn, smooth and corrugated shafts can be single-walled and double-walled. Moreover, the design of the well itself can be telescopic, that is, retractable.
Initially, polymer models were made of two parts: the neck and tray.The chute part was supplied with piping wiring corresponding to the purpose of the well. Currently, direct-flow models are also provided for direct-flow structures.
A huge advantage of polymer products is the complete waterproofing of their shafts. This gives such facilities an absolute advantage, which over time will provide them with priority in the market for construction products.
Conclusions and useful video on the topic
This video demonstrates the advantages of models made of modern polymers over products made of reinforced concrete.
Modern plastic wells not only look more attractive than their reinforced concrete counterparts, they weigh less and are better waterproofed. The future, of course, is theirs.
Without a sewer system, it is impossible to imagine the life of a civilized society. And without sewers of various types, not a single sewer system can carry out its work. Now you have an idea of what these structures are like, how they are built and what materials are made.
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