Sewer wells: types, sizes, device

2024 Author: Aaron Duncan | [email protected]. Last modified: 2023-12-16 03:30

Improvement of a private house or settlement is closely related to water supply and, accordingly, sanitation. Therefore, a sewer well is an indispensable part of the life support of a civilized society.

Several decades ago, only reinforced concrete wells were used, and sometimes improvised wells. Now plastic wells are becoming more and more popular.

Below will be considered in more detail what types of wells are and why they are needed. And also what are the advantages and disadvantages of products from different materials.

Classification of sewer wells

Sewage wells can be classified in several ways: by material of manufacture, by installation network and by method of use.

According to the material of manufacture, the wells are divided into:

polymer (plastic) - any durable plastic is suitable;
concrete and reinforced concrete - made from concrete rings;
brick - brickwork is used;
from improvised materials, such as tires.

According to the network on which the wells are being installed, they are divided into:

household -necessary for the reception and removal of sewage and fecal matter from residential buildings;
industrial - used to receive and dispose of waste from production and various chemical masses;
drainage - necessary for the removal of groundwater, which can cause destruction of the foundation or swamp the area;
stormwater - used to drain rain and melt water.

Classification of wells by purpose:

examination (revision);
drop;
filtration;
cumulative.

Let's consider in more detail the types of wells by purpose and by the material of manufacture.

Manholes: purpose, types, device

A viewing sewer well is necessary to monitor the entire sewerage system and eliminate emerging breakdowns in time. It is for this reason that they are mounted where faults are most likely to occur. Also, such a well is needed for cleaning and repairs if necessary.

The sewer well device consists of parts such as:

bottom, where the outlet and inlet pipelines are connected;
work chamber;
directly the well shaft;
inlet neck;
manhole cover (should be easily accessible).

Wells of this type must be installed:

where observation should be, even if a breakdown is unlikely to occur;
where toside pipes are connected to the main pipeline;
where the flow is to be turned;
where changes in the parameters of the pipeline (slope or diameter) take place, which, in turn, can affect the speed and width of the flow.

Inspection typical sewer wells are divided into:

Rotary. They are installed where the sewer pipe turns 90o. Such places can be quite problematic due to blockages.
Linear. They have the simplest design and are mounted on straight sections of communications at a certain distance (35 m or 50 m depending on the diameter of the pipe).
Nodal. Such wells are installed where it is necessary to make branches to the main pipeline.
Control sewer wells are installed where local pipelines are connected to central ones.
Flushing. These wells are installed at the very beginning to flush the network.

Inspection wells are installed in sections longer than 50 m, every 35-300 m, depending on the diameter of the pipe: the smaller the section, the shorter the distance. For private houses, the first manhole is installed 3-12 m from the house.

Drop wells: classification and device

Their main function is to regulate the speed of runoff water. Depending on the task that they must perform, overflow sewer wells also have their own classification. According to their design, they are divided into the following types:

Fast currents -the simplest type of well. The bottom line is a sharp slope, which greatly speeds up the flow.
Tubular. The main element of such a well is a vertical pipe. It is used if the height of the drop is not more than 3 m, and the diameter of the pipe is not more than 60 cm.
Wells with a fender and spillway wall have a fairly simple design. The bottom line is to slow down the wastewater thanks to the wall installed in the middle.
With a practical profile drain and a water well.
With cascading differential (multi-stage). The flow of water slows down due to drops from one stage to the next.

This type of sewer well device is necessary:

when it is necessary to bypass other communications or pipes;
to slow down (in some cases increase) the speed of movement of runoff water;
when the depth of the incoming pipeline becomes smaller;
if the site has a natural slope.

Storage wells

The storage sewer well is the largest of all types. Its main function is to collect all the impurities that come from a private house. The size of such a well primarily depends on the number of people living on the site. Considered the most environmentally friendly type.

Storage type wells are usually mounted at the lowest point of the site. In this way, a natural angle of inclination is achieved, which allows runoff water to move spontaneously under the influence of gravity.

A prerequisite for a well is its tightness. Since the presence of gaps allows sewage to seep into the ground. And this, in turn, causes the appearance of very unpleasant odors. It may also enter groundwater.

In the storage well, wastewater is divided into layers: heavy precipitation falls to the very bottom, and light inclusions remain on top, respectively. Such a well is cleaned with the help of sewage trucks.

Seepage wells

Wells with a filtering function are similar in their task to accumulative ones. The difference lies in the fact that runoff water does not linger, but, on the contrary, moves into the ground, having previously passed the so-called filtration. In this way, the incoming water is collected and purified.

Filtration wells have a design similar in principle to other types, but the main difference is the absence of a bottom. More precisely, it is, but not in the usual sense. The basis of the device is replaced by a natural filter of many layers and steps. The filter layer includes a mixture of coarse sand and crushed stone.

Such wells can only be installed where the earth has a high absorbency. For example, peat bogs, sandstones, sandy loam. But on clay soil, it does not make sense to install such a well due to the high density of the soil. It is forbidden to install on rocks that have cracks due to the possibility of runoff water getting into drinking water. Above groundwater, the structure must be at least 1 m higher.

Mandatory requirements:

the distance between the well with drinking water and the filtration facility is not less than 30 m;
filtration area for sandy loam - 1.5 m², and for sandstone - 3 m² (recommended)^;
water consumption per day no more than 1 m3 (this is usually enough for a family of 5);
if there are plastic water pipes, the distance should be at least 1.5 m.

Reinforced concrete rings of sewer wells

They have been around for a very long time. According to experts, concrete sewer wells are the most durable and most efficient. Any type of wells can be installed from this material, but most often these are inspection and overflow wells.

Typical sewer wells have the following advantages:

Small price even considering labeling and purpose.
You can install on any ground.
Convenience and ease of installation. Although this requires the involvement of large equipment.
Long service life.

Disadvantages of a reinforced concrete sewer well:

Concrete rings are made as standard as possible. Accordingly, the installation site is not taken into account, and this causes some inconvenience - holes for pipes are drilled directly at the installation site.
Since the well is prefabricated, there is an opinion about poor sealing. Water is exchanged through the holes: groundwater enters the well and overflows it, and wastewater enters the soil, whichpoisons her.
Inconvenient cleaning. This can only be done by two people and only by manual labor.

Plastic for wells

Plastic sewer wells are gaining more and more popularity. It is hard to believe that this material only recently began to be used for the sewer system.

Advantages of plastic manholes:

No need for constant maintenance. Previously, it was required to make a volume of at least 70 cm in order for a person to climb through. Now you can make a well with a diameter of 30 cm, saving material and effort for installation.
Easy to lift due to low weight. The corrugated pipe is easy to compress and pull, which is very convenient in various situations. It is also easy to transport and install.
Long service life. As you know, plastic does not wear out for a long time.
Full waterproofing. Only mechanical damage can break it.
Resistant to the harsh environment that inevitably comes from wastewater.
Resistance to temperature extremes - from -50 to +70 Celsius.
Smooth inner surface to avoid build-up.
Ability to use for repairing old concrete wells (just insert inside).
Presence of ready-made holes for pipes.

Disadvantages of plastic:

not suitable for seasonal soil;
not designed for large volumes.

Existing sizes

Sizeplastic sewer wells are mostly standard, regardless of configuration and structure.

Let's consider in more detail the possible parameters of plastic wells:

well inner diameter: 0.6-1m, 1.2m and 1.4m;
well height: from 1 m to 6 m;
well wall thickness: 2.5cm, 3.1cm, 4.4cm, 6.2cm;
neck height: from 50cm to 80cm;
pipe diameters: 11 cm, 16 cm, 20 cm, 25 cm, 31.5 cm, 40 cm and 50 cm;
pipe length is usually 30cm;
the distance from the bottom of the well to the nozzle is usually also 30 cm.

If we talk about concrete rings, then their height is 0.9 m. But the diameters are as follows: 0.7 m, 0.8 m, 0.9 m, 1 m, 1.5 m and 2 m.

Calculating the size of wells

To calculate the required size of the sewer well, you can use a simple formula.

For example, you can take a family of 3-4 people. One person consumes about 150 liters per day, which means that for the whole family - about 700 liters. It is important to remember that this does not take into account data on the consumption of water by household devices. The three-day rate will be about 2.4 m3. You also need to take into account the fact how often there are guests. Since, as a result, the wastewater that enters the well should not be higher than 1 m.

To calculate the required number of reinforced concrete rings, you can use this formula.

As an example, take the daily amount of stockwater - 600 l. Next, multiply this number by 3 and as a result we get 1800 liters (1.8 m³). Concrete rings have a standard height of 90 cm, and the internal section is in the range from 0.7 m to 2 m. Let's take a value of 1 m. And now we calculate the volume: Pi (3, 14)radius squared (0, 50.5)well height (0.9 m). The result is 0.7 m^{3. We look at the previously calculated number of wastewater and get 3 rings (with a margin).}

Conclusion

Sewerage is something that a modern person cannot do without. A well is an integral part of the sewer. They are necessary for collecting sewage, cleaning blockages and repairing pipelines. A variety of shapes and the right choice of material greatly facilitate the solution of many issues related to the sewer system.