Septic in clay soils. The technology of the septic tank in clay soil

Many owners of country houses are interested in whether it is possible to make a septic tank on clay. The main problem with the installation of a sewage treatment plant on this type of soil is that the pre-treated waste water after passing the septic tank is discharged into the soil, and clay does not pass and filter the water well. However, even on clay soil, an autonomous treatment plant can operate efficiently and for a long time, provided that it is properly installed. In our article, we will consider the different types of septic tanks that can be made on clay soil, as well as the features of their design and choice.

To make it easier for you to understand which septic tank is needed for clay soils, you need to study the features of this soil. In order to equip an effective sewage system, sewage after treatment in a septic tank is discharged into the ground. The main feature of clay soils is poor absorbency. Earth does not absorb liquid well. This leads to the fact that waste water stays 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, equipping a septic tank of concrete rings, plastic or metal containers, it is necessary to organize effective drainage. It can be a drainage well made of concrete rings without a bottom with a filter layer or a filtration field.

What septic tanks can be used in clay?

If your summer house or country house is located on a site with clay soil, then for the treatment of effluents coming from the house through the sewers, you can use the following types of treatment facilities:

Storage tanks . For these purposes, you can use sealed containers made of plastic or Eurocube. However, metal tanks made of stainless steel are also suitable for clay soils. You can also make a sealed well of concrete rings, if the water level in the area is high. For a small private house, you can make a brick drainage well, provided that the correct technology is used.
Sewage treatment plants . This is a fairly effective, budgetary and simple option for a small country house built on clay soil. The well of such a treatment plant can be made of concrete rings, brick or metal, that is, any material can be used for such soil.
Biological treatment units - This is the most reliable and effective option for clay soils, suitable for a private house of any size. However, such a septic tank on clay will have the most complex design, so it is worth making a choice if you have the money and time to complete it.

Important: the sewer 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 sewage treatment plant on such soil. In this case, the choice should be made taking into account the performance of the structure, the required degree of wastewater treatment and water treatment.

Storage tanks

If you decide to equip the sewerage 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.

Performing such a treatment plant is quite easy. It is enough to dig a pit, concrete the bottom and install tanks or concrete rings. However, if there is a well at your site with a high water supply or near a storage tank, then this design is not recommended.

Soil treatment designs

These simple sewage treatment plants are very reminiscent of storage tanks, but only without a bottom. The design of the well itself can be made of concrete rings, brick or a bottomless daughter. A drainage layer is arranged at the bottom of the structure.

To make a drainage filter, it is necessary to use geotextiles, sand and gravel. The thickness of the filter layer is 30-40 cm. When passing through this filter, the effluents are cleaned of large fractions and enter the soil.

If a well is located near your site, then this design of the treatment plant is also not suitable. When arranging this septic tank, you need to know the UHF, because the bottom of the filter layer cannot approach the aquifer closer than 1 m.

Units with biological treatment

These are the most reliable and effective treatment facilities, which can be installed independently of the water treatment facilities at the site. These autonomous biological treatment plants purify effluents so effectively that water can then be used to irrigate the garden, drained into open water or taken for technical needs.

Usually these are multi-chamber products, where the drains immediately from the sewer are divided into heavy and light fractions. Then the clarified waters go through the process of biological purification using bacteria (anaerobic or aerobic).

Design Features

Since on clay soil for the sewerage of a country house you can use any design of a septic tank, the construction scheme will be standard. However, the main feature of clay soils is that it is a moving soil. Therefore, it is worth considering some design features of the septic tank.

The thing is that when the soil begins to thaw after winter cold, the characteristics of such soils change slightly and they can push the septic tank to the surface. This is especially true for soils with high GW and septic tanks made of light materials. That is why, when installing a septic tank in clay, it is necessary to provide additional fixatives in the ground. If the well of the treatment plant will be made of concrete rings, then it is enough to simply fill it in the foundation pit without fixing it.

The choice of method for fixing the septic tank in the pit depends on the design of the body. If there are no protrusions on the surface of the tank, then steel cables are more suitable. If on the case there are hinges or ledges, then it is possible to bind the outlets of the fittings to them, which will be laid in a concrete cushion at the bottom of the pit.

Also, the filtration system for septic tanks on clay soil has some features. When installing a septic tank in clay, it is better to equip a double drainage, that is, two filtration fields. In this case, the drainage should be in the form of a two-stage trench, in the upper part of which pipes will be laid, and in the lower one a drainage layer 300 mm high of gravel will be made.

Mounting Features

To perform a more efficient septic tank design, it is recommended to use two chambers and a filtration field. So you can avoid overfilling the tank and get the most purified water at the outlet of the treatment plant. After you decide on the material of the cameras, you can start digging the pit and further work that is performed in this order:

When choosing a place for a septic tank, you can observe the minimum recommended gaps from the apartment building and sources of drinking water (7 m), since clay does not pass water well. The size of the pit for the treatment plant should be 20 cm larger than the design of the septic tank itself.
When digging a pit, you need to know at what depth the clay layer ends. If it is more than three meters, then the work will be complicated by the fact that the drainage layer will have to be performed at a considerable depth. It is also worth considering that the septic tank is connected by overflow, so they should be located at a distance of 15-20 cm from each other.
Together with the foundation pit, they dig a trench for laying a sewer pipe from the house to the treatment plant. At the same time, the slope of the bottom of the trench from the house to the septic tank is observed, taking into account that for each meter of length the decrease is 2 cm.
Depending on the containers used, the bottom of the pit can be concreted before or after installation. If you use plastic sealed tanks, the bottom is concreted and reinforced before installation. And after installation, these tanks are attached with hummocks to the valve outlets. When using concrete rings, the bottom can be concreted after they are installed in the pit.
To perform the filter layer at the bottom of the second chamber, sand and gravel are used. First, sand is poured and compacted with a layer of 10-15 cm, then backfill is made of gravel with a height of 25-30 cm. If you use the filtration field, the bottom of the second chamber is also concreted, and drains are diverted to the filtration fields.
Next, an overflow pipe is installed connecting the two tanks. It should exit the first chamber 40-50 cm below the entry point of the sewer pipe. Due to this, heavy components of the sewage will settle at the bottom of the first chamber, and previously purified and clarified waters will fall into the second tank.
Mounted ventilation pipes from the chambers.
After that, plastic containers are insulated with foam. Insulation is not required for concrete rings.
Tanks are covered with covers with hatches for cleaning.
Now backfill the foundation pit manually. Every 15-20 cm the soil must be rammed. The manhole cover must remain above the surface of the earth.

The filtering field is made depending on the groundwater level in the area:

with low GWP, semi-recessed filter cartridges or filters are used;
at high GWF, surface filtration is applied on sand and gravel cushions.

Important: the size of the filtration field is directly related to the daily volume of effluents from the house.

One square meter of filtration field is capable of serving 0.5 cubic meters of effluent. You can purchase ready-made filter wells based on geotextiles or do the field yourself:

After digging the soil from the field, the pipeline is laid from the last septic tank to the filtration field. The laying depth is 70-120 cm from the surface of the earth, but not less than 1 m to the groundwater level.
A drainage grid is laid at the bottom of the field. Then a layer of sand and gravel is performed. The height of the interlayer must be such that it rises above the inlet pipe by no more than 50 mm. All pipes with holes are laid with a slope of 1 cm per meter of length.
The drainage pipe is insulated with foam or a wooden box.

The life of a modern person is filled with various objects that provide comfort and convenience. These include water spent in the house, bath fixtures, and a toilet.

But such comfort systems, if they are not part of the general system, the presence of which is possible in urban apartment buildings, need an individual wastewater and waste treatment system. Previously, people dispensed with the usual sewage pit, from which the drained masses were absorbed into the soil, and when they accumulated excessively, ditches were cleaned using special machines or the foundation pit was simply transferred to another place.

The disadvantage of this method of disposal of sewage was the saturation of the soil and even water wells with pathologically dangerous microorganisms, which, as a result, caused many diseases of humans and animals. As well as contamination of the land and bringing it into a state of unsuitability for agricultural use.

In order to protect the earth and humans from dangerous microorganisms, wastewater treatment systems were invented, our company has been engaged in installing such systems for many years.

The cheapest and easiest installation option for cleaning today is a septic tank, which is a complex single-section or multi-section design that provides partial purification of wastewater and its absorption into the soil or partial drainage. At the same time, a septic tank provides for soil filtration in which the liquid passes through the soil layers, for this, good drainage properties of the soil and a considerable field of drainage action are needed.

Installation of a septic tank on clay soil

For the sake of economy, many people use septic tanks and install them in clay, but such a solution is simply a waste of money and labor. Whatever myths go around septic systems, they are intended for sand or other types of soil capable of rapidly absorbing liquid.

They are not suitable for a clay environment due to poor drainage of this type of soil layer - our experts always explain this to the owners of clay areas, but they do not always listen and drive themselves into unnecessary waste. The recent case of a septic tank in clay has become a vivid example of the irrelevance of such treatment equipment for clay terrain.

People turned to us because of a septic tank malfunction, when opening the foundation pit, our experts found a completely deformed container, completely unsuitable for cleaning anything.

Why are septic tanks set in clay deformed?

By itself, a septic tank is not able to absorb a large amount of water, since it is designed for low-volume runoff, in addition, it requires good drainage, that is, so that part of the purified water goes into the soil.

Absorption of liquid is not characteristic of clay, and this leads to the accumulation of liquid around the septic tank or complicates the work for the drain pipe, which, in turn, simply cannot accommodate the amount of liquid calculated to pass through the soil layer. Thus, pressure is applied to the casing of the cleaning device and it is deformed.

Due to the obstruction of the soil, water simply crushes the septic device. An additional destructive factor is such a feature of clay as frosty bloating, in which in winter the clay soil itself begins to put pressure on the septic tank and either pushes it out or deforms if it is firmly fixed.

Making a surface outflow of water is also not relevant, since a septic tank does not completely clean the liquid masses and draining such water into a ditch or pond threatens the spread of harmful bacteria, which means it promises environmental problems.

What to do if the septic tank is deformed?

Many people who have encountered failure of a septic tank installed in clay blame the manufacturers of the septic installation or the people who carried out the installation. At the same time, the unfortunate owners again order and install a similar treatment system, and after a short time they again get the same result.

The only solution to this problem, as practice shows, is to replace the wastewater treatment system with one that is suitable specifically for clay. The most practical solution for non-absorbable soil is considered a biological treatment station, which is relevant for any type of soil.

It was this decision that our experts made, taking the above-mentioned deformed septic tank out of the ground, and it turned out to be the only correct one.

The thing is that the operation of the septic tank is based on absorbed soil and an extensive filtration field, for which clay cannot act as an action field, since it does not allow water to pass through. The sewage pipe of the equipment is not able to do the work for the soil, that is, to miss such a large amount of water, in which case the septic tank itself is deformed if it is made of fragile materials, such as polypropylene, or the pipe breaks if the casing of the cleaning device is made of concrete mixtures .

Features of biological treatment plant

The main advantage of a biological station is that it is suitable for any type of soil. It differs from a septic tank and a high level of purification, which is about 98%. In fact, any impurities, thanks to special microorganisms, on the influence of which the operation of the device is based, are converted by this installation into two types of useful raw materials: clean industrial water and compost.

Since the water obtained after filtration using a biological station is completely safe, it can be drained into a ditch, used for watering plants or for other technical needs, and no environmental indicators will be violated. The resulting solid raw materials can be safely used to fertilize the soil and plants. Important can be called such features of a biological station:

Compact, since such a cleaning device does not take up much space;
Tightness and strong structure, in which the ingress of sewage into the soil or water bodies is completely eliminated;
Duration of operation, which can reach more than 50 years;
An opportunity to use the raw materials received after cleaning for technical purposes.

Principles of installing a septic tank

Septic tank is the simplest form of sewage treatment plants, while its installation requires compliance with certain rules. Due to the fact that such a cleaning system is not particularly safe, since it is not typical for complete cleaning of liquids, such a device should be located no closer than twenty meters from a residential building.

An additional condition during installation is the location of a well or a well with drinking water, the distance between it and the septic installation should be no more than 50 meters.

For clay soils that have low drainage, but are considered an excellent medium for the spread of bacteria of the intestinal group, this distance can be figuratively increased to 80 meters.

The principle of operation of the septic tank is based on the settling of the waste, so its capacity should be designed for a three-day rate of liquid waste, so that they have time to settle. In clay soil there is no possibility for re-soil filtration, and when sedimented, the liquid leaves poorly due to the strength of the clay, which makes the septic tank relevance a common myth.

Principles of installing a biological treatment plant

The biological treatment plant is less overall because it does not imply a process of prolonged settling. Unlike a septic tank, in which sewage should be idle for three days, this device allows you to clean the raw materials in a time not exceeding several hours.

At the same time, additional soil filtration is simply not necessary, because the processing and purification of effluents is carried out due to the impact of biological organisms (bacteria) on them, for which waste becomes a food product. As a result of such biological processing, the water obtained as a result of processing can be discharged into any reservoir, ditch, ravine or used for watering plants, since it does not contain hazardous substances at all.

The body of the biological station is always tight and made of durable materials, so for the installation you can not move the treatment station to a large distance from the living room, and since the waste after such cleaning is safe, you should not be afraid of the proximity of the installation to a well or water pipes.

Another advantage of this treatment equipment can be called the fact that it does not require insulation, since it works from the network and provides for preheating.

What to choose?

Some owners of clay areas still prefer to use a cheaper septic tank instead of a biological treatment system and are looking for options for its proper installation.

Many not-so-conscientious experts offer additional fixation of the septic tank, in order to prevent its expulsion in cold weather. Often it is recommended to install a septic device near the surface in order to provide at least partial drainage and filtering with the upper soil layer. At the same time, for the possibility of functioning, the device is insulated with the help of additional materials.

All these methods are only theoretically good; in practice, any of them will soon lead to the destruction of the septic tank and malfunctions in the autonomous sewer system.

If the site is endowed with clay soil, the only way of high-quality wastewater treatment is a biological treatment station, without which it is simply impossible to make an autonomous sewer system located on glinchaks.

It so happened that our comfort and additional amenities often become the cause of environmental pollution, especially in places with clay soil. In order not to harm the environment, each owner of a private sewer system is simply obligated to take responsibility for wastewater treatment.

Savings in the form of a septic tank will then be the wrong decision, with unforeseen consequences, based on this, preference should be given, after all, to a biological treatment plant.

The selection of a septic tank for clay soil and its installation are complex tasks that require compliance with a number of rules. Incorrect installation of such structures on loams can cause septic deformation and disruption of its operation.

It is difficult to establish a septic tank on clay, because the characteristics of this soil do not predispose to the rapid disposal and treatment of wastewater. Clay does not absorb water well. Drains are retained in the tank. Sandy soil is capable of absorbing up to 90 liters of water per day, while loams - only 25 liters. Pure clay is characterized by lower water absorption rates. In addition, clay soils are characterized by high density and high weight. When arranging an autonomous sewage system, these features must be taken into account.

Why are septic tanks set in clay deformed, and how to avoid this?

Most often, when equipping septic tanks, large-capacity plastic containers are used. They are a good option for many types of soils, but they are not quite suitable for clay. Having high density and weight, clay with seasonal temperature fluctuations often deforms containers, even from dense plastic. In some cases, deformation of even metal containers is possible. In addition, septic tanks in clay soil are often deformed due to soil movements. This is especially common if groundwater is too close to the surface.

When planning the installation of a septic tank in clay soil, one must take into account the danger of a possible deformation of the tank. In order to prevent the occurrence of such a problem, it is desirable to use rigid materials, including concrete rings, slabs, etc., to equip the structure.

If desired, you can use plastic containers. But to protect them from soil movements, it is necessary to make a special construction made of concrete or a strong wooden crate. This will avoid a violation of the integrity of the tank due to soil pressure. If the groundwater level is low, metal reinforcement or corners can be used to make the battens.

What septic tanks can be used in clay?

When arranging a septic tank on clay soil, it should be borne in mind that it is almost impossible to create high-quality filtration fields, so classic multilevel systems should be abandoned. There are several options for autonomous sewers that can be effectively used.

Storage tanks

The simplest and cheapest option for a septic tank, suitable for arrangement in clay soil, is a storage system. In the conditions of clay soil and to save further funds for pumping water, you can use a complex storage system, consisting of several tanks interconnected. Such cleaning systems can be created based on:

concrete rings;
bricks;
large metal barrels;
plastic containers, etc.

Such a septic tank for clay soil is an analogue of a cesspool and requires the systematic pumping of accumulated effluents with a sewage machine.

With soil treatment

Septic tanks, consisting of several storage tanks and an artificially created filtration field, can reduce the cost of pumping waste water. In this case, some of the already settled sewage will fall into the filtration field and go into the soil. The design in this situation will be simple. Several tanks are connected in series with each other so that heavily contaminated drains remain in the first of them, and already settled water penetrates into the next tank.

It does not have to be only 2 containers. Some owners of personal plots connect 3-4 containers at once. This allows you to ensure that in the last cavity of the septic tank, the water gets almost clean. The difficult moments of arranging such a system are preparing the site and installing the filtration field system.

Due to the presence of clay in the place where the filtration field will be located, it is required to dig a pit 1 m deeper than the bottom of the pit intended for installation of the system. At the bottom of the pit gravel or gravel is poured, as well as a layer of sand. Perforated pipes are laid inside such a pillow so that purified water from the last container can be diverted to the filtration field. It must be borne in mind that on top of the pipes there must be at least 50 cm of rubble and sand.

In the process of shrinkage, the filtration field can become clogged with clay and cease to fulfill its function. To delay such an unfavorable outcome, you should cover the finished filtration field with geotextiles. Clay can be poured over this material. This will avoid bloating the clay and clogging the cavities between the gravel.

For biological treatment

Closed septic tanks with biological treatment are very popular among clay plots owners. Such systems are autonomous sewer stations. They give a high degree of purification, therefore 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 effluents are immediately subjected to fractional division, settling. The clarified effluents are additionally cleaned with special bacteria that process all present organic compounds.

Design features of a septic tank for clay

The physical properties of clay soils change slightly during freezing and thawing. This often causes the septic tank to gradually push to the surface. Especially this problem often arises when installing septic tanks, which were made of light materials, including plastic and metal.

To prevent the appearance of this effect, fixing the structure in the pit is required. For additional fixation, metal reinforcement and concrete mortar are often used. If the surface of the tank is equipped with special holes, metal cables can be used to fix it on the bottom of the pit.

In addition, to prevent the displacement of the tank, it is recommended that a thick substrate of gravel and sand be arranged. It is also allowed to manufacture a concrete slab, which will perform the function of the foundation. When pouring it, you can make "ears". With their help, it is possible in the future to more securely attach the septic tank to the base.

When performing earthwork during the arrangement of autonomous sewage, all safety measures must be observed, since clay can quickly collapse. It is best to dig a septic tank pit no less than 1.5 m wider and longer than required. This will avoid surprises due to the collapse of clay.

Features of installation on clay soil

When planning the installation of a septic tank on clay soils, it is necessary to comply with the sanitary requirements for the location of autonomous treatment facilities. The distance to the house and other capital buildings should be at least 20 m.

In addition, if a septic tank for clay soil has a filtration well and will purify water not only due to the operation of a cesspool machine, it must be taken into account that the distance to the well or other water source must be at least 50 m. This will prevent pollution by drinking water effluents.

It is best to start installation when dry weather sets in for a long time. This will reduce groundwater. When digging a pit, all safety precautions should be observed. The height of the pit should be at least 70 cm greater than the height of the selected septic tank. At the bottom of the pit, 10 cm of sand is laid. After this, a 30 cm layer of gravel is poured. On top of this, laying geotextiles is recommended.

After that, the connected reinforcing mesh, necessary for pouring the concrete substrate, is laid at the bottom of the pit. If necessary, a wooden or metal crate is formed to protect the septic tank from being squeezed. After the bottom of the pit is prepared, you can proceed to the installation of the design of the septic tank. Be sure to fix the container with cables or metal rods. After that, you need to install all the communication pipes, fill up the cavities around the septic tank and compact the soil.

Installation of local treatment systems for sewage (septic tanks) is often complicated by geological conditions (soil composition) and a high level of groundwater.

These reasons create problems with the discharge of treated effluents into the ground. The most difficult thing is to mount a septic tank on clay, which has a minimum coefficient of filtration of liquids.

The main problem at this stage is related to the fact that almost all clays (90%) relate to soils prone to frost heaving. It is because of this reason that it is possible to squeeze the installation to the surface, so it is necessary to resort to additional fastening of the local treatment plant during installation. Most often, a so-called bandage made of steel strips or cables is used, which encircles the septic tank and is attached to the concrete base in the pit.

Given that on clay soils drainage systems (filtration fields) in many cases work only in the upper layers of the soil, it is necessary to resort to a shallow laying of the septic tank.

In this case, it is necessary to provide measures for the insulation of the structure:

Glass septic tank insulation

In the simplest case, they resort to filling an additional layer of soil above the relief (they form a hill above the installation site of the septic tank).
More effective is the insulation of the treatment plant with special insulating materials, the choice of which is quite wide. The most affordable (at a cost) method is to fill the container with expanded clay. The use of expanded polystyrene (preferably extruded) or polyurethane foam is considered more effective. In addition, systems of active protection against the effects of freezing temperatures are increasingly being used. To do this, use a heating electric cable, the thermal power of which will reliably protect the septic tank from freezing, even in severe climatic conditions.

Sewage disposal

The main problem for those who decided to build an autonomous sewage system and mount a septic tank in clay soil is the difficulty of discharging treated effluents. Such soil is characterized by minimal filtering ability, which creates a number of sometimes difficult problems.

There are several basic ways of discharging treated effluent from a septic tank under such conditions.

It is used if the soil does not accept water at all. In this case, the entire volume of treated effluents enters an airtight container or well, from which it is then pumped out using sewage machines or drainage pumps.

The disadvantages of this method include the need for a large capacity device, otherwise pumping will have to be performed very often. But if there is no other way, it is necessary to apply this technology.

Increased drainage area

There are several varieties of this technology, but they all boil down to the need to increase the filtration area, so that even with minimal drainage ability of the soil to ensure the removal of the required volume of treated effluents.

The device of a number of consecutive drainage wells, while it is necessary to use rings of the maximum possible diameter.

In practice, systems of two or three overflow drainage wells are used, which can fully meet the needs of a family of 3-4 people.

To increase the filtering ability of wells, they resort to drilling additional drainage wells. This method allows in some cases to reach the filtering horizons of the soil, which will help to significantly increase the productivity of the structure. Drilled wells must be protected using casing pipes, and a simple mesh filter must be installed at their mouth to prevent siltation of additional drainage.

Set a septic tank in clay with your own hands it is possible with the device of the filtering fields of a significant area. This method is used for high water level (groundwater level).

The most productive is the drainage system using corrugated plastic pipes and geotextiles. Pipes of this type are characterized by increased strength, they are able to provide effective drainage of treated effluents. And geotextiles prevent siltation of the system.

To increase the efficiency of the filtration field, it is often used to lay a two-level drainage. In this case, a number of lines (drains) are laid not far from the surface, and the main part is buried as far as the groundwater level allows.

Laying the filter line is carried out in pre-prepared trenches, which are covered with a geotextile. Drainage pipes with a thickness of at least 20 cm are laid on a granite crushed stone bedding (it is not recommended to use another because of the tendency to erosion). From above, they are also covered by a layer of rubble, which can significantly increase the volume of discharged effluents. The entire system obtained is closed with geotextiles, which will ensure the longevity of the line.

To ensure effluent filtration in clay soil conditions, it is necessary to lay significant filtering fields in area.

Of course, the installation of septic tanks in clay involves a significant increase in the volume of work performed during installation. But to ensure the effective operation of local wastewater treatment plants even in such conditions is quite possible.

In order to organize sewerage in a private house, so that the septic tank serves for a long time and remains strong and tight, in addition to many nuances, it is necessary to take into account the type of soil. Currently, different types of septic tanks are used, which are installed underground and above ground. The above-ground, however, is already used very rarely, since they emit an unpleasant odor that spreads to the site.

Choosing a place to install a septic tank on clay soil

When digging a hole underground, you can use a gravel bed or a concrete pad. The latter option is more preferable, especially if it is planned to lay polymer containers.

Installation Features

When installing a septic tank, the following are taken into account:

soil type;
groundwater level;
location of the house itself;
fence and other buildings;
vegetable garden.

Based on this, the depth is calculated where they will conduct the sewer pipe. It should be at least seventy-five centimeters. The level of clay freezing in the cold season, which, incidentally, is high, is also taken into account. The septic tank must be installed so that the filtration passes above the groundwater level, otherwise the absorption will be insufficient. After laying, the pipe is covered with earth until a small slide is received.

It is desirable to insulate a septic tank with polystyrene foam.

In order for it to be firmly fixed underground, it is necessary to provide good drainage, otherwise the tank may go deep into the soil. After the construction of the pit, a diversion is carried out for dispersal. It will also be useful to install a drainage pump.

soil and septic tank installation

In order for the septic tanks in clay to be perfectly fixed, it is additionally desirable to attach them with steel ropes. The filtering trenches should be two-stage. The right pillow is made of gravel and sand thirty centimeters thick. At a depth of fifty centimeters to a meter, a perforated pipe is laid for filtration. In the second trench, the pipe is already located at a depth of one and a half to two meters.

It is more difficult to install a septic tank on a clay basis due to the characteristics of this type of soil: its average porosity has a poor ability to pass fluid. Therefore, special attention should be paid to drainage or filter floor. This will entail additional material costs. If the clay thickness exceeds three meters, it is necessary to replace part of the soil with crushed stone and sand, since these materials have excellent throughput.

The installation location of the septic tank must be designed in such a way that it is as far away as possible from the point of intake. For clay soil, such a distance can be from twenty meters. The sump itself is laid below the freezing depth of the soil due to the heaving properties of clay.

Thus, despite the difficult nature of this type of soil, it is possible to install a septic tank, but the behavior of clay soil should be taken into account.

Types of septic tanks

For clay soil, not all types of septic tanks are suitable.

Capacities for the sewer system are divided by the nature of the work on:

accumulative, in the form of sedimentation tanks that are cleaned as sewage accumulates;
for deep cleaning, after which water can be used;
for soil filtration, when purified water completely leaves the soil.

In the last two cases, all containers of the septic tank also need to be periodically cleaned, but they do it much less often than in the first case.

Devices can be:

monolithic;
national teams.

According to the manufactured material, they are divided into septic tanks from:

reinforced concrete;
brick;
metal;
plastic.

In their form, septic tanks are:

horizontally installed;
vertically mounted.

They consist of:

one camera;
two cameras;
multiple cameras.

Storage septic tanks for clay soil

This type of sewer septic tank is a pit or special containers that are placed in dug pits. The bottom is treated, drained or a pillow of concrete is laid. In the excavated pits, the effluents are separated into light substances that will float and heavy solid waste settling to the bottom. Such a septic tank is very easy to install, but it is inconvenient to operate it, as an unpleasant smell will come from it.

installation of Biotank septic tank for clay soil

Storage septic tanks come in plastic or fiberglass. They are tight and do not corrode, but require installation that provides strong stability of the device. Sometimes septic tanks are built simply from brick or reinforced concrete rings.

Some owners of suburban areas dig a hole, install the formwork and fill it with concrete. But this will be a good solution only in the case of a small plot and for temporary residence in a private house. In addition, for such a septic tank it will be necessary to call a suction tank for cleaning quite often, and the smell coming from the pit will not add any comfort to being out of town.

This type of septic tank is well suited for clay soil, especially if it is well fixed.

Septic tank with soil treatment

For such a septic tank, in which soil post-treatment is provided, the cleaning machine is called less often than for a simple storage tank. This type of septic tank provides for a larger barrel than in the accumulative form. But it is more difficult to install it in the ground, since additional protection measures should be provided here.

A concrete pillow is laid on the bottom, a septic tank is placed and secured with chains. This is done so that it holds firmly in one place and cannot be pushed out, which can happen in the cold season. Also, it must be protected from the fact that when burying just do not crush the ground. To do this, it is filled with water when instilled. Sometimes special batteries are used, which at times can reduce the frequency of cleaning. A septic tank of this type is not difficult to install on its own. Wastewater in it first falls into one chamber, where it is divided into layers, one of which settles, and the other, on the contrary, floats. Partially clarified water then enters the next chamber, where it decomposes using anaerobic bacteria artificially planted there. In the second chamber, water is thus purified by sixty percent.

installation of storage tank for septic tank on clay soil

Such septic tanks are quite simple to use and are often used. However, for clay soils, alas, they are not suitable. Rather, the implementation of the method is possible when laying an artificial sand filter and an additional structure for water drainage. But to do this is not only too difficult, but also quite costly. Therefore, on such soil, usually, a septic tank with soil post-treatment is not used.

Biological deep cleaning

Biologically treated septic tanks are reliable and durable. With their help, high-quality cleaning occurs, as a result of which water can be used for technical needs. The method used is a combination that provides deep cleaning. Moreover, in addition to mechanical sedimentation, chemical and biological methods are used.

The waste mass in it is cleaned as follows. First, as in previous types of septic tank, they enter the sump, where a layer of more or less purified water is formed. She moves to the next chamber, where anaerobic bacteria, which carry out secondary treatment, are planted. After this, the water does not go outside, but continues to be purified chemically, resulting in the highest level of purification, reached ninety-eight percent.

Of course, not a single septic tank used in private country houses can guarantee a hundred percent cleaning. Therefore, you should never drink such water. But it is quite applicable for technical needs. So, with it you can water the garden, flower beds or just grass near the house, as well as wash cars and more. You can install it either with your own hands or by resorting to the help of specialists. It all depends on the complexity of the design.

soil preparation for septic tank installation

Such sewage on clay soils is possible in the same way as on other soils. However, the disadvantage here is the high price of the septic tank. The purchase of this device will be justified only if people live permanently in the house. Typically, it requires an electrical network. Therefore, for smooth operation, care must be taken to ensure that there are no surges in electricity. Often an autonomous system is used for this.

Installation at high GW

If the groundwater level is high on the site, it is better if professionals install the septic tank. You can do it yourself too, but you need to prepare for a difficult job.

Between the walls of the septic tank and the pit, gaps of ten to fifteen centimeters are left.

A sand pillow is laid below, with a thickness of at least five to ten centimeters, and if the water underground is too close to the surface, then the formwork is used.

Care should be taken to backfill, since if it is not performed correctly, this can cause the tank to move. The left distance between the septic tank and the pit is covered with sand.