Choosing a septic tank for clay soil and installing it is complex tasks, requiring compliance with a number of rules. Incorrect installation of such structures on loam can cause deformation of the septic tank and disruption of its operation.
It is difficult to install a septic tank on clay, because... the characteristics of this soil do not predispose to rapid disposal and treatment of wastewater. Clay does not absorb water well. Wastewater is retained in the tank. Sandy soil can absorb up to 90 liters of water per day, while loam soil can absorb only 25 liters. Pure clay is characterized by lower water absorption rates. In addition, clay soils are characterized by high density and heavy weight. When settling in autonomous sewerage these features must be taken into account.
Most often, when installing septic tanks, large-volume plastic containers are used. They are good option for many types of soils, but they are not entirely suitable for clay. Possessing high density and weight, clay often deforms even thick plastic containers during seasonal temperature fluctuations. In some cases, deformation of even metal containers is possible. In addition, septic tanks in clay soil are often deformed due to soil movement. This happens especially often if groundwater lies too close to the surface.
When planning to install a septic tank in clay soil, you need to take into account the danger of possible deformation of the container. To prevent the occurrence of such a problem, it is advisable to use rigid materials for the construction of the structure, including concrete rings, slabs, etc.
If desired, you can also use plastic containers. But to protect them from soil movements, it is necessary to make a special structure made of concrete or a strong wooden sheathing. This will avoid damage to the integrity of the container due to soil pressure. If the level groundwater low, you can use metal reinforcement or corners to make the sheathing.
When installing a septic tank on clay soil, it should be taken into account that it is almost impossible to create high-quality filtration fields, so classic multi-level systems should be abandoned. There are several options for autonomous sewers that can be used effectively.
The simplest and cheapest option for a septic tank, suitable for installation in clay soil, is a storage system. In clay soil conditions and to save money on pumping water in the future, you can use a complex storage system consisting of several containers connected to each other. Such cleaning systems can be created based on:
Such a septic tank for clay soil is an analogue of a cesspool and requires systematic pumping of accumulated wastewater with a sewer truck.
Septic tanks, consisting of several storage tanks and an artificially created filtration field, can reduce the cost of pumping wastewater. In this case, some part of the already settled wastewater will enter the filtration field and go into the soil. The design in this situation will be simple. Several containers are connected in series so that heavily contaminated wastewater remains in the first one, and the already settled water penetrates into the next container.
There doesn't have to be only 2 containers. Some owners of personal plots connect 3-4 containers together at once. This makes it possible to ensure that almost clean water enters the last cavities of the septic tank. The difficult aspects of arranging such a system are preparing the site and installing a filtration field system.
Due to the presence of clay in the place where the filtration field will be located, it is necessary to dig a pit 1 m deeper than the bottom of the hole intended for installing the system. Gravel or crushed stone, as well as a layer of sand, are poured into the bottom of the pit. Perforated pipes are laid inside such a cushion so that purified water from the last container can be discharged to the filtration field. It must be taken into account that there must be at least 50 cm of crushed stone and sand on top of the pipes.
During the shrinkage process, the filtration field can become heavily clogged with clay and cease to perform its function. To delay such an unfavorable outcome, the finished filtration field should be covered with geotextiles. Clay can be poured on top of this material. This will prevent the clay from swelling and clogging the cavities between the crushed stone.
Closed septic tanks with biological treatment are very popular among owners of sites with clay soils. Such systems are autonomous sewerage stations. They provide a high degree of purification, so in the future the resulting water can be used for technical needs and for irrigation of the site.
Such autonomous sewers are multi-chamber products, where the wastewater is immediately subjected to fractional division and settled. Clarified wastewater is further purified by special bacteria that process all organic compounds present.
The physical properties of clay soils change slightly during periods of freezing and thawing. This often causes the septic tank to gradually push to the surface. Especially this problem often occurs when installing septic tanks that were made of lightweight materials, including plastic and metal.
To prevent the appearance this effect fixation of the structure in the pit is required. For additional fixation, metal reinforcement and concrete mortar. If the surface of the container is equipped with special holes, you can use metal cables to fix it to the bottom of the pit.
In addition, to prevent the container from moving, it is recommended to install a thick base of gravel and sand. It is also possible to manufacture concrete slab, which will serve as a base. When pouring it, you can make “ears”. With their help, you can later more securely attach the septic tank to the base.
When performing excavation work when installing an autonomous sewer system, all safety measures must be observed, since the clay can quickly collapse. It is best to dig a septic tank hole at least 1.5 m wider and longer than required. This will avoid surprises due to clay collapse.
When planning to install a septic tank on clay soils, you must comply with the sanitary requirements for the location of autonomous treatment facilities. The distance to the house and other permanent buildings must be at least 20 m.
In addition, if a septic tank for clay soil has a filtration well and will purify the water not only through the operation of a sewage disposal machine, you need to take into account that the distance to the well or other water source must be at least 50 m. This will prevent wastewater pollution drinking water.
It is best to begin installation when the weather has been dry for a long time. This will ensure a reduction in groundwater. When digging a pit, all precautions should be taken. The height of the pit must be at least 70 cm greater than the height of the selected septic tank. A 10 cm layer of sand is placed at the bottom of the pit. After this, a 30 cm layer of gravel is poured. Laying geotextiles on top of this is recommended.
After this, a connected reinforcing mesh is laid at the bottom of the pit, which is necessary for pouring the concrete substrate. If necessary, a wooden or metal lathing to protect the septic tank from compression. Once the bottom of the pit has been prepared, you can proceed to installing the septic tank structure. Be sure to secure the container with cables or metal rods. After this, you need to install all the communication pipes, fill the cavities around the septic tank and compact the soil.
1.
2.
3.
4.
5.
6.
Choosing a septic tank for installation on clay soil is a serious task, because the design must perform its functions efficiently and be able to clean wastewater from pollution. In addition, some designs allow the use of purified water in a second cycle. The implementation of such a project will be discussed in this article.
The last indicator must be considered in more detail, since the efficiency of the entire structure depends on it. For example, one square meter sandy soil can absorb about 90 liters of liquid per day.
IN sandy loam soils this volume is reduced to 50 liters; loamy soils can process no more than 25 liters. In the case of dense clay soil, the situation is even worse: the soil can absorb less than 5 liters of water per day. That is why a septic tank on clay is performed slightly differently than conventional designs. You also need to know what to do if your septic tank stinks. There are many drugs and remedies to solve this problem.
Choosing suitable solution, it is worth first studying in detail the types of soil located on the site. You can find out from the old residents of the area, neighbors who have recently spent construction works, or order geological exploration. Last option will have maximum accuracy, and there is a point in studying the geology of the site: making a septic tank in clay is much easier and cheaper than purchasing a ready-made station biological treatment, which is only good for the most difficult situations.
Structurally, a septic tank on clay soil can be made in any way: you can install a plastic, brick, reinforced concrete or concrete system. Clay soil does not affect the choice of material at all, so this issue rests entirely on the shoulders of the homeowner, and depends on personal preferences and the amount of finance allocated for construction. Quite often, do-it-yourself installation of concrete rings for sewerage is done, which allows you to reduce costs.
This septic tank design is well suited for summer cottages, but it is not practical to use it in country houses where people permanently live. Another disadvantage is the low degree of purification, as a result of which the treated wastewater has a characteristic sewer smell. To avoid this problem, you will have to use a septic tank with aeration.
Similar treatment plants operate on similar principles:
Conclusion
As can be seen from this article, a septic tank in clay soil is not big problem. The main thing is to correctly understand the characteristics of the site and choose the most suitable design that best suits the specific situation.
Today you can install any septic tank for your dacha with your own hands, for which you have not only the time, but also the funds. Before purchasing, it is better to calculate the approximate volume of wastewater and determine the type of soil on which such a container will be installed. One of the obstacles may be such difficult soil as clay, on which it is difficult to carry out installation. Therefore, you should choose a septic tank carefully. Today, several types of waste storage containers are used. These are aboveground and underground. Above-ground containers are used extremely rarely, which occurs not only because of their unhygienic nature, but also because unpleasant odor, which they spread around. The most optimal is an underground septic tank installed in the soil.
To arrange the bottom of a hole that is dug in the ground, two options are used:
Let's find out what types of septic tanks are for summer cottage you can install it yourself, how realistic it is to do it in clay.
Features of installing a septic tank in clay
For installation sewer septic tank At the dacha, it is necessary to take into account the following points:
The degree of sewage treatment in a septic tank is at least 60%.
Such a pipe can be laid at a depth of 75 cm, taking into account the level of freezing in winter time. For clay soil where the groundwater level can be quite high. You can only install a septic tank with your own hands, the ground filtration of which will take place above the water level. Otherwise, the suction will be poor, that is, the installation of the septic tank will be incorrect.
The pipe is laid shallow; it is simply sprinkled with a small amount of earth on top so that a low hill is formed.
To install a septic tank in clay with your own hands, you will first have to provide excellent drainage so that the container does not go into the soil. To do this, not only a pit is built for the container, but also a drain for dispersion; it is recommended to install a drainage pump.
Installation of a septic tank sanitary standards, allowed at a distance of at least 5 meters from the house.
The pit for the barrel must be made deep, but the level of freezing must be taken into account so that the barrel does not simply get crushed. It is better to secure septic tanks in clay further using steel channels. It is required to install two-stage filter trenches. The right one should have a cushion of sand and gravel 30 cm thick. It is in this trench that the filtering perforated pipe is laid, the depth of which should be from half a meter to one. The pipe should be placed in another trench of the system to a depth greater than in the first - from one and a half meters to two.
Not every septic tank can be used for clay. Let's consider the most preferable options.
Types of septic tanks for country houses
With your own hands you can arrange in your dacha different kinds septic tanks All types of containers for the sewer system can be divided according to different criteria. According to the principle of operation, septic tanks built by yourself can be classified into:
If there is a well with drinking water on the site, then the septic tank should be located at least 30 meters from it.
It is customary to divide sewage tanks according to materials of manufacture:
Based on their shape and installation, septic tanks can be divided into vertical and horizontal. There is a division by type of chamber (surface and underground). According to the principle of operation, septic tanks can be divided into:
Cumulative septic tanks and with soil post-treatment 
Sold specifically for sewerage concrete blocks with bottom. This greatly simplifies the installation of a septic tank.
Storage septic tanks are cesspools and storage tanks, which are pits or special barrels. Such containers are installed in special dug holes; a special drainage or concrete pad is installed for the bottom of such holes. In prepared pits, the wastewater is divided into two parts: light substances and fatty residues float to the top, hard and heavy substances sink to the bottom. Among the advantages, it is necessary to note the simplicity of execution, but such a septic tank is inconvenient for operation, since it must be cleaned frequently, and the smell from which it originates is quite unpleasant;
Septic tanks with soil post-treatment differ in that it is necessary to call a sewage disposal truck for cleaning less often than for a regular one. The volume of such barrels is larger, but their strength is much higher. The device requires more force than a conventional storage device, and when installed in the ground, some protective equipment must be provided.
A concrete pad is used for the bottom, on which the barrel is placed; chains are attached to it to hold the barrel in place, since in winter such a septic tank is simply pushed out. And when digging into the ground, it is necessary to ensure that the walls of the septic tank are not crushed by the soil. For such options, you can use batteries for septic tanks, which can significantly reduce the frequency of waste treatment. The principle of operation of such a septic tank, which you can easily install with your own hands, is quite simple: wastewater through a pipe first flows into one chamber, where it is located, like in a sump. Here they are divided into separate factions. After this, the initially purified water enters another chamber, where it is further purified under the influence of anaerobic bacteria. 60% purification occurs here.
The advantage of such septic tanks is their ability to process wastewater. They are characterized by simple maintenance; sewer equipment is not used for cleaning. The disadvantage is this: this type of septic tank cannot be installed on clay soil; there is no way to provide a hole for the bottom the necessary conditions, and cleaning at the last stage is simply impossible in this case.
Biological deep cleaning
From the house to the septic tank, the pipe should be laid at an angle.
Such septic tanks are considered the most modern and reliable; they allow you to completely purify wastewater, after which the water can even be discharged into fish ponds. The deep cleaning method is used here, that is, it uses combined method. This is not only mechanical settling of wastewater, but also chemical, biological methods purification of water entering septic tanks. The operating principle of a biological septic tank is as follows: the first chamber accumulates wastewater and separates it into heavy and light fractions.
This is followed by cleansing using aerobic and anaerobic bacteria. Before water is discharged, it is cleaned with special chemicals.
Biological septic tanks, which are easy to install with your own hands, are characterized by high,
almost one hundred percent level of purification. Such devices can be installed even on very heavy soils, including clay. Installation is simple, the station is ready for use in about two days. The downside is the high price. If you are going to install a septic tank in a country house where you plan to live only in the summer, then there is simply no point in such an expensive installation.
Other options for septic tanks
Now let's consider the type of storage containers depending on what material is used for this. Plastic and fiberglass septic tanks are produced industrially from very durable materials. The advantages of such barrels are that they are sealed, that is, they do not allow leaks and are resistant to corrosion. Among the disadvantages, it should be noted that plastic barrels have a small mass. When installing such a septic tank, it is necessary to use a special concrete pad for the bottom, to which the barrel will be attached with chains or steel ropes. There is a high probability that the walls of the barrel will simply be crushed under the weight of the soil. For such containers, there is often little concrete bottom; the walls must be protected in the same way.
There are septic tanks that are constructed from ordinary bricks, for which one-brick masonry is used. But such septic tanks are used only for small areas where significant volumes of wastewater are not planned. Although septic tanks are easy to build using only your own hands, it is simply impossible to create a complete seal here. It is necessary to ensure ventilation of the pit and its frequent cleaning. Reinforced concrete septic tanks can be monolithic or prefabricated. In the first case, a hole is made into which formwork is installed and filled with concrete. In the second case, apply for wells. There is an option in which the septic tank is constructed from a metal tank, which must be pre-treated with anti-corrosion compounds.
www.liveexpert.ru
When installing a homemade or purchased septic tank great importance given to the quality parameters of the soil. The nature of the soil, freezing depth (DF), and groundwater level (GWL) play a role. Considering that in middle lane the most common type of soil is clay, many owners suburban area are faced with the problem of arranging an autonomous sewage system. The catch is that clay and loam are different throughput– liquid passes very slowly through layers of such soil. In turn, this entails additional costs when arranging a drainage area - a filtration field.
If installing a settling tank in clay is not particularly difficult, then the drainage of the septic tank should be given increased attention. In situations where the thickness of clay and loam exceeds 3 meters, you should be prepared to carry out full-scale excavation work. In particular, it will be necessary to replace part of the soil with crushed stone and sand - materials that have good throughput. It is also necessary to provide for a slight slope of the pit under the aeration field (2-3 degrees), which would be sufficient to discharge treated wastewater into roadside trenches or onto an unoccupied (unowned) site.
In the situation we are considering, it is worth considering increasing the absorbing area of the filtration field. This means that the network should be branched out as much as possible. drainage pipes(don’t forget about insulating the septic tank), using large area. It is good if the use of treatment plants is seasonal, but in the case of constant use of the installation, the septic tank structure must undergo some changes. In particular, it is necessary to take into account the terrain and rely on the construction of a treatment plant as far as possible from the house. Perfect option, when there is a natural reservoir on the outskirts of the site. In this case, the slope of the drainage area can be made in its direction, and then the reservoir will play the role of a collector without harming the environment.
Considering the heaving nature of clay and loamy soil, it is necessary to correctly approach the installation of a septic tank, i.e. strive to ensure that most of the sedimentation tanks are below the depth of soil freezing. It is not necessary to follow the path of deepening the pit for containers - it is enough to make an artificial embankment above the treatment plant.
oseptike.ru
To make it easier for you to understand what kind of septic tank is needed for clay soils, you need to study the characteristics of this soil. To arrange effective system sewerage, wastewater after treatment in a septic tank is discharged into the ground. The main feature of clay soils is poor absorption capacity. The earth does not absorb liquid well. This results in wastewater remaining in the treatment plant longer.
It is important to know: sandy soil absorbs 90 liters of water per day, the absorption capacity of clay soils is 25 l/day. And pure clay absorbs more less water– 20 l.
That is why, when installing a septic tank made of concrete rings, plastic or metal containers, it is necessary to organize effective drainage. It could be drainage well made of concrete rings without a bottom with a filter layer or a filtration field.
If your dacha or Vacation home are located on an area with clay soil, then to process the wastewater coming from the house through the sewer, you can use the following types treatment facilities:
Important: sewage from a country house on clay soil can be diverted to a septic tank of any design. It is important to properly design and install a treatment plant on such soil. In this case, the choice should be made taking into account the productivity of the structure, the required degree of wastewater treatment and groundwater treatment.
If you decide to equip the sewer system of a private house using storage tank, then you need to make a sealed structure. For these purposes you can use plastic containers, eurocubes, steel barrels or welded cubes, structures made of concrete rings or bricks.
It is quite easy to carry out such a cleaning installation. It is enough to dig a pit, concrete the bottom and install containers or concrete rings. However, if your area has a high groundwater level or there is a well near the storage tank, then using such a design is not recommended.
These simple treatment plants are very similar to storage tanks, but only without a bottom. The structure of the well itself can be made of concrete rings, bricks or bottomless water. A drainage layer is installed at the bottom of the structure.
To make a drainage filter, you need to use geotextiles, sand and crushed stone. The thickness of the filter layer is 30-40 cm. When passing through this filter, the wastewater is cleared of large fractions and enters the soil.
If there is a well nearby on your site, then this design of the treatment plant is also not suitable. When installing this septic tank, you need to know the groundwater level, because the bottom of the filter layer cannot approach the aquifer closer than 1 m.
These are the most reliable and efficient treatment facilities that can be installed regardless of the water supply system on the site. These autonomous biological treatment stations purify wastewater so effectively that the water can then be used to water the garden, drained into open reservoirs, or taken for technical needs.
Usually these are multi-chamber products, where the wastewater directly from the sewer system is divided into heavy and light fractions. Then the clarified water undergoes a process of biological purification using bacteria (anaerobic or aerobic).
Since any septic tank design can be used on clay soil to sewer a country house, the construction scheme will be standard. However main feature Clay soils are that they are mobile soil. Therefore, it is worth considering some design features of the septic tank.
The thing is that when the soil begins to thaw after the winter cold, the characteristics of such soils change somewhat and they can push the septic tank to the surface. This is especially true for soils with high groundwater levels and septic tanks made of light materials. That is why, when installing a septic tank in clay, it is necessary to provide additional fasteners in the soil. If the well of the treatment plant is made of concrete rings, then it is enough to simply fill it in the pit without fixing it.
The choice of method for fixing the septic tank in the pit depends on the design of the housing. If there are no protrusions on the surface of the tank, then steel cables. If there are loops or protrusions on the body, then the outlets of the reinforcement can be tied to them, which will be laid in a concrete pad at the bottom of the pit.
Also, the filtration system for a septic tank on clay soil has some features. When installing a septic tank in clay, it is better to arrange double drainage, that is, two filtration fields. In this case, the drainage should take the form of a two-stage trench, in the upper part of which pipes will be laid, and in the lower part there will be a drainage layer 300 mm high of gravel.
To perform more efficient design For a septic tank, it is recommended to use two chambers and a filtration field. This way you can avoid excessive overfilling of the tank and at the exit from the treatment plant you will receive the most purified water possible. After you have decided on the material of the chambers, you can begin digging a pit and further work, which is carried out in this order:
The filtration field is made depending on the groundwater level in the area:
Important: the size of the filtration field is directly related to the daily volume of wastewater from the house.
One square meter of filtration field is capable of serving 0.5 cubic meters of wastewater. You can purchase ready-made filter wells based on geotextiles or make the field yourself:
vodakanazer.ru
Most often they are used as plastic containers, in particular Eurocubes of various sizes. But barrels and homemade welded cubes can be installed of stainless steel. The storage container can be made of brick or concrete. Such septic tanks are often found in villages and towns. They are easy to set up: just dig a pit the right size, after which its bottom and walls are laid out with bricks. Or they install concrete rings with a diameter of 1 m and concrete the bottom of the pit.
They are the most reliable and modern. These products are autonomous biological wastewater treatment stations capable of producing water that can be used for watering a garden or discharged into a pond with fish. The operating principle of such septic tanks is to separate fractions into heavy and light. This is facilitated by the design of the station.
The main work of wastewater treatment is performed by aerobic or anaerobic bacteria. The life activity of the former is possible only under the condition of constant air pumping. The latter live in silt or soil and do not need additional stimulation. These stations can be installed on heavy soils, including clayey ones.
These are the simplest wastewater storage tanks to set up. They are arranged in a similar way to storage tanks, but without concreting the bottom. That is, you can use all the same materials: brick, concrete, plastic or iron, but you need to install a drainage layer at the bottom. It is made of sand and crushed stone. Here, large fractions are filtered, after which the wastewater penetrates the clay and receives better purification.
Such septic tanks are good because the sewer truck needs to be called less often than in the case of storage tanks. However, in clayey soil the process of filtration and wastewater removal will be hardly noticeable. Therefore, you will have to pump out sewage with the same regularity as if you have a container with a concrete bottom. Such a septic tank can be built quite quickly with your own hands.
In clay conditions, if the groundwater level (GWL) is below 1.5 m, semi-buried filters or filter cassettes are installed. At high groundwater levels, it is rational to arrange surface filtration using gravel-sand pads.
The dimensions of the post-treatment field depend on the daily water consumption in the house. If the volume of wastewater does not exceed 0.5 m³, according to established standards, a filter area of 1 m² will be sufficient. If the daily volume of wastewater is more than 1 m³, a field measuring 1.5-2 m² will be required. There are ready-made designs of filter wells available for sale. The price of these products is low, and installation is simple. The role of the main filter in them is played by geotextiles. But if you buy finished design There is no desire or opportunity; you can do the post-treatment field yourself.
After the soil is removed, a pipe is laid connecting the second container with the filtration field. As a rule, the laying depth is 0.7-1.2 m from the ground surface, but not lower than 1 m from the groundwater level. The bottom of the pit is leveled and a drainage mesh is installed on it. After which sand and crushed stone are poured. The height of the pillow should be such that its top rises above the inlet pipe by at least 5 cm. We should not forget that the pipes are installed taking into account the required slope. It must be at least 1* per 1 m. Pipes must be insulated using a wooden box and polystyrene foam.
Since such soil is not capable of good fluid permeability, a drainage system will be required to remove rain and flood water from the tanks for receiving sewage. To do this, not wall drainage, but ring drainage is performed. To install the pipeline you will need drains. You can use purchased perforated pipes or make your own from sewer pipes. plastic pipes diameter 110 mm. Perforation is carried out with a drill 1.5-2 mm thick at a distance of 2-2.5 cm from each other. The holes should be staggered.
A trench is formed around the septic tank so that its bottom is 20-30 cm below the freezing point of the soil. Next, the bottom is leveled with a slope that should be at least 1 cm per 1 m towards the storage well. After this, they fill it with 5-7 cm of sand and 10-15 cm of gravel. Then geotextiles are laid on the bottom of the trench. A pipeline is installed inside the ditch and the pipes are wrapped with previously laid material. Then they begin backfilling.
Clay is a highly heaving soil. This property is especially evident if it is wet rather than dry. During seasonal freezing and thawing, such soil can easily push a plastic or other container placed in it out of the hole. Therefore, during the installation of containers for sewage drainage, provision should be made for their fastening in the pit.
This can be done using metal rods, which can be angles or small diameter pipes. The purpose of the rods is to fix the location of the container and prevent it from moving during soil heaving. For this purpose, you can also use steel chains, one end of which is firmly fixed in the soil.
For deeper wastewater treatment, two-stage trenches can be made for the filtration field. In the upper part of such a ditch there are pipes through which wastewater is discharged, and in the lower part there is a sand and gravel cushion up to 30 cm thick. Using such trenches, you can build a full-fledged filter system and remove wastewater outside the site.
The depth of the pits should be such that the liquid in the pipes does not freeze in winter, that is, below the freezing point of the soil. Each pipe will need to be perforated by analogy with the drainage pipe, but the holes should be larger, since the liquid will be included small fractions. To prevent clogging of the holes with soil, each pipeline element is wrapped with geotextile.
masterseptika.ru
A septic tank for clay soil should have some design differences from conventional devices. To understand how a septic tank works in clay, you need to remember how conventional treatment plants work: first, the wastewater enters the sump, being divided into light and heavy fractions, and then the purified water enters the soil, where final purification occurs. To organize soil cleaning, filter wells are used, the design of which includes perforated walls and a drainage bottom. But the performance of such a system depends on several factors: laying depth, wall area, soil water level and the type of soil prevailing in the area.
The last indicator must be considered in more detail, since the efficiency of the entire structure depends on it. For example, one square meter of sandy soil can absorb about 90 liters of liquid per day.
In sandy loam soils this volume is reduced to 50 liters; loamy soils can process no more than 25 liters. In the case of dense clay soil, the situation is even worse: the soil can absorb less than 5 liters of water per day. That is why a septic tank on clay is constructed somewhat differently than conventional structures.
Despite the fact that the problem seems insoluble, there are still methods for solving it, and their implementation does not require digging an ordinary cesspool, which will then have to be cleaned regularly. Regardless of the type of prevailing soil on the site, a high-quality local treatment plant can be created if all the factors affecting its performance are properly taken into account. The following will describe possible solutions that allow you to use a septic tank in clay.
As a rule, the layer of clay soil rarely has a thickness of more than 2-3 meters. This can be noticed when constructing a well: under the upper layers of the earth’s surface you will find sandy loam soils, or even clean sand, which has an excellent water absorption rate. In this case, the well will work much better than it could work in homogeneous soil: the water column will create high pressure.
When choosing a suitable solution, you should first study in detail the types of soil located on the site. You can find out from the old residents of the area, neighbors who have recently carried out construction work, or order a geological survey. The latter option will have maximum accuracy, and there is a point in studying the geology of the site: making a septic tank in clay is much easier and cheaper than purchasing a ready-made biological treatment station, which is only good for the most difficult situations.
Structurally, a septic tank on clay soil can be made in any way: you can install a plastic, brick, reinforced concrete or concrete system. Clay soil does not affect the choice of material at all, so this issue rests entirely on the shoulders of the homeowner, and depends on personal preferences and the amount of finance allocated for construction.
If there is good fertile black soil on the site, you can reuse water purified by a septic tank to water the plants. To implement such a project, you will need to make the following design: the filter well must be replaced with a sealed tank to which a drainage pump is connected. This pump will supply purified liquid to the irrigation system.
This septic tank design is well suited for summer cottages, but it is not practical to use it in country houses where people permanently live. Another disadvantage is the low degree of purification, as a result of which the treated wastewater has a characteristic sewer smell. To avoid this problem, you will have to use a septic tank with aeration.
Sometimes even the densest soils demonstrate good absorption qualities. Of course, this does not always manifest itself, but if a soil analysis has shown that it can absorb at least a small amount of water, then you can take advantage of this and increase the absorption area. To implement this idea, filtration fields are used.
The structure is prepared as follows:
This solution is quite convenient: in this case, little depends on the degree of wastewater treatment, because the smell will not be able to escape. In addition, if the depth of the pipes is more than 40 cm, then the sewer can be used even in winter, since the pipeline will not freeze. The disadvantage of the design is the impossibility of its use on soils that are completely impermeable to water.
In the case of soils that do not absorb moisture at all, you can dispose of wastewater directly onto the site or into a special ditch. Naturally, such a system implies maximum wastewater purification (from 95%) and absence of odor. To implement the design, it is best to use energy-dependent septic tanks using aeration.
Similar treatment plants operate on similar principles:
Conclusion
As you can see from this article, a septic tank in clay soil is not a big problem. The main thing is to correctly understand the characteristics of the site and choose the most suitable design that best suits the specific situation.
kanalizaciyadoma.com
When installing septic tanks, the following nuances must be taken into account:
Groundwater level and soil type.
The location of the place to install the septic tank relative to the house, well, fence.
Is there drainage from this area (ditches, drainage).
The depth at which a pipe passes from a building.
The degree of slope of the site.
In absolutely ideal conditions, the installation of a septic tank can be carried out at a depth of at least 75 cm from the surface layer of the earth, in order to protect the container from freezing in winter. So, for example, in some regions of Russia, the depth of ground freezing in winter according to SNiP is 140 cm, but in reality for a septic tank 75 cm will be more than enough.
Let's consider the option of installing a septic tank with clay soil and extremely high level groundwater. In this case, the installation of a septic tank must be done so that the filtration field (drainage) made after the septic tank is slightly higher than the water level, otherwise the runoff will not be absorbed very well in the soil, which means that such a septic tank installation will not be considered correct. The septic tank should be installed shallowly and lightly sprinkled with earth on top to form a slide. It can also be insulated using polystyrene foam, insulation, for example, K-flex-ST or its analogues. When installing a septic tank in water, it is required to anchor it using concrete beams. The septic tank itself will almost always be full of water, and therefore, to prevent it from floating, too much mass is not required to strengthen the septic tank in the soil. If the installation of a septic tank is carried out in very difficult conditions, for example, in a swamp, then the installation of the septic tank must be done using a concrete slab (the septic tank in this case is attached to the slab using metal strips), with further lowering of this structure using a manipulator into the pit.
When installing septic tank in clay very difficult to do required field dispersion, because drainage from crushed stone will begin to collect all the water from the site 
from rain, and therefore the drainage will be in the liquid and it will not drain well. This means that the drain can be made into a ditch, or a special well can be made at the very end of the dispersion field in order to install a drainage pump in it, with further pumping of water into the drainage ditch.
A septic tank consists of one or more separate chambers. Waste liquid passes through them. The configuration of the septic tank and the depth of its placement depend, first of all, on the performance of the structure and its overall dimensions. It is necessary to lay the septic tank on a soil that is not subject to swelling and other deformations during severe freezing or thawing.
If cold winter the soil freezes significantly, then the container is placed in a sufficiently deep pit, and its bottom should be in a non-freezing layer of soil, or on a special foundation in the form of a concrete cushion. The simplest septic tanks, like the “Tank” or “Triton” system, are usually buried so that the thickness of the soil from the soil surface to the septic tank body is no less than half a meter.
For the normal stable operation of any treatment plant of this type, it is extremely important that flood waters do not stagnate in any case, and the height of groundwater is certainly more than one meter. If your site is poorly drained, then the septic tank is laid shallow and covered with soil so that a small hill about 50-70 cm high is formed. All technological openings must be left free access. It is worth considering that the angle at which the liquid flows through the chambers of this septic tank must be at least 50.
In addition, for a septic tank to work well in clay or other dense soil (heavy loam) that does not allow water to pass through well, it is necessary to install two-stage filter trenches. The first trench is equipped with a sand-gravel cushion 30 cm thick. A perforated filter pipe is laid in it at a depth of approximately 0.5-1 m, in the other trench - at a depth of 1.5-2 m.
Popular articles:
Choosing an inexpensive septic tank for your dacha, design and turnkey installationMany owners of country houses are interested in whether it is possible to make a septic tank on clay. the main problem with the construction of a treatment plant on this type of soil is that pre-treated wastewater, after passing through a septic tank, is discharged into the ground, and clay does not allow and filter water well. However, even on clay soil, an autonomous treatment plant can operate effectively and for a long time, provided correct device. In our article we will look at different types septic tanks that can be made on clay soil, as well as the features of their design and selection.
To make it easier for you to understand what kind of septic tank is needed for clay soils, you need to study the characteristics of this soil. To create an effective sewage system, wastewater after treatment in a septic tank is discharged into the ground. The main feature of clay soils is poor absorption capacity. The earth does not absorb liquid well. This results in wastewater remaining in the treatment plant longer.
It is important to know: sandy soil absorbs 90 liters of water per day, the absorption capacity of clay soils is 25 l/day. And pure clay absorbs even less water - 20 liters.
That is why, when installing a septic tank made of concrete rings, plastic or metal containers, it is necessary to organize effective drainage. This can be a drainage well made of concrete rings without a bottom with a filter layer or a filtration field.
If your dacha or country house is located on an area with clay soil, then the following types of treatment facilities can be used to process wastewater coming from the house through the sewer system:
Important: sewage from a country house on clay soil can be diverted to a septic tank of any design. It is important to properly design and install a treatment plant on such soil. In this case, the choice should be made taking into account the productivity of the structure, the required degree of wastewater treatment and groundwater treatment.
If you decide to equip the sewer system of a private house using a storage tank, then you need to make a sealed structure. For these purposes, you can use plastic containers, Eurocubes, steel barrels or welded cubes, structures made of concrete rings or bricks.
It is quite easy to carry out such a cleaning installation. It is enough to dig a pit, concrete the bottom and install containers or concrete rings. However, if your area has a high groundwater level or there is a well near the storage tank, then using such a design is not recommended.
These simple treatment facilities are very similar to storage tanks, but without a bottom. The structure of the well itself can be made of concrete rings, bricks or bottomless water. A drainage layer is installed at the bottom of the structure.
To make a drainage filter, you need to use geotextiles, sand and crushed stone. The thickness of the filter layer is 30-40 cm. When passing through this filter, the wastewater is cleared of large fractions and enters the soil.
If there is a well nearby on your site, then this design of the treatment plant is also not suitable. When installing this septic tank, you need to know the groundwater level, because the bottom of the filter layer cannot approach the aquifer closer than 1 m.
These are the most reliable and efficient treatment facilities that can be installed regardless of the water supply system on the site. These autonomous biological treatment stations purify wastewater so effectively that the water can then be used to water the garden, drained into open reservoirs, or taken for technical needs.
Usually these are multi-chamber products, where the wastewater directly from the sewer system is divided into heavy and light fractions. Then the clarified water undergoes a process of biological purification using bacteria (anaerobic or aerobic).
Since any septic tank design can be used on clay soil to sewer a country house, the construction scheme will be standard. However, the main feature of clay soils is that it is mobile soil. Therefore, it is worth considering some design features of the septic tank.
The thing is that when the soil begins to thaw after the winter cold, the characteristics of such soils change somewhat and they can push the septic tank to the surface. This is especially true for soils with high groundwater levels and septic tanks made of light materials. That is why, when installing a septic tank in clay, it is necessary to provide additional fasteners in the soil. If the well of the treatment plant is made of concrete rings, then it is enough to simply fill it in the pit without fixing it.
The choice of method for fixing the septic tank in the pit depends on the design of the housing. If there are no protrusions on the surface of the tank, then steel cables are more suitable. If there are loops or protrusions on the body, then the outlets of the reinforcement can be tied to them, which will be laid in a concrete pad at the bottom of the pit.
Also, the filtration system for a septic tank on clay soil has some features. When installing a septic tank in clay, it is better to arrange double drainage, that is, two filtration fields. In this case, the drainage should take the form of a two-stage trench, in the upper part of which pipes will be laid, and in the lower part there will be a drainage layer 300 mm high of gravel.
To make a more efficient septic tank design, it is recommended to use two chambers and a filtration field. This way you can avoid excessive overfilling of the tank and at the exit from the treatment plant you will receive the most purified water possible. After you have decided on the material of the chambers, you can begin digging a pit and further work, which is carried out in this order:
The filtration field is made depending on the groundwater level in the area:
Important: the size of the filtration field is directly related to the daily volume of wastewater from the house.
One square meter of filtration field is capable of serving 0.5 cubic meters of wastewater. You can purchase ready-made filter wells based on geotextiles or make the field yourself:
