Such soil belongs to the category of problematic soil and is considered “heavy”, not only literally, but also figuratively. Excavation work carried out in areas with clay soil is characterized by its specifics. How is it expressed in relation to the installation of a biorefinery station?
Local structures of this category can be installed on any soil. And this is one of the advantages of such septic tanks for autonomous sewerage. However, there is a point that is not taken into account by all land owners who, in an effort to save money, try to carry out the entire cycle of activities on their own. Installation of a biorefinery station is carried out on clay soils only after a series of engineering calculations. Therefore, inviting a specialist (at least for professional consultation) is more than rational decision. Otherwise, during operation of the septic tank deep cleaning Problems may arise that you cannot cope with on your own.
So what are the features of clay soil? The main difficulty is the minimal absorption of liquid due to the increased density of the earth. What does this mean in practice?
- The removal of clarified liquid must be carried out forcibly. On clay soils it is not advisable to organize a natural discharge. Or rather, it’s impossible. Therefore, when choosing a biorefinery station model, you need to take this nuance into account.
- Groundwater is located quite high. Since it is necessary to prepare a pit for the installation of the station, there may be a problem with its constant flooding. Even with forced drainage, it is unlikely to be completely resolved.
- On clay soil any septic tank, including the station, does not fit to a significant depth. This means that you will need additional insulation housings. For most regions of the Russian Federation, this topic is more than relevant, considering how low the thermometer drops in winter. In relation to a biorefinery station, another difficulty lies in the fact that for bacteria to function normally, they need to be provided with maximum favorable conditions. Consequently, on this point, it is necessary to correctly calculate everything - the type of heat insulator, the thickness of the layer, the method of laying it.
The design for clay soil type must be chosen especially carefully, because it must be a high-quality sewer system, which, moreover, will clean the wastewater from sewage and remove it simply clean water. Some models will even allow you to reuse water that has already gone through one cycle, although, of course, not for drinking purposes.
The fact is that sandy soils can absorb up to ninety liters of liquid per day. If it is sandy loam, then this figure is reduced to fifty liters, loam - two times less. And if you have dense clay soil, then it will absorb no more than five liters of water per day. Therefore, the sewer system is built according to different canons.
As a rule, clay in the soil is located only in the upper two to three meters. This is noticeable, for example, if you equip a well: below you can see sandy loam or even clean sand, which perfectly absorbs water. The well works even better this way than if the soil were homogeneous due to the pressure of the water column. Thus, first study in detail the type of soil on your hacienda. Ask old-timers, neighbors, those who recently built something, or simply order geologists who will conduct professional exploration. Then you can save on arrangement septic tank in clay instead of buying a ready-made cleaning station.
The design of the septic tank can be anything - plastic, brick, reinforced concrete or concrete. You can choose the material without regard to clay soil, based on your budget and personal preferences. If on your site good black soil, then you can water the crop with purified water from the septic tank. To do this, you will need to install a sealed tank instead of a filter well, and connect it to drain pump. Then the supply of purified liquid will be provided to the irrigation system.
Septic tank in clay: reviews, installation, where to drain the water. Such a septic tank is suitable for a dacha, but if you constantly live in a house outside the city, then it is not advisable to buy such a septic tank. Another disadvantage is that the percentage of purification is quite low, so there may be bad smell. But it can be neutralized with an aeration system.
However, very often even the densest soil shows good absorbent properties. You can use this and increase the area that absorbs water using filtration fields. To do this, fill the entire area with crushed stone, and lay drains with two-centimeter holes on them. The length depends on the number of residents. There should be a ten-meter pipe for each person. It is also necessary to fill ten centimeters of crushed stone on top, and put black soil on top. You can plant plants on it that need plenty of watering. This is a convenient solution because the degree of cleaning does not affect anything, and there will be no smell either. If you lay the pipes at a depth of forty centimeters or greater, then they will not freeze in winter, and you can continue to use the septic tank. However, in soils that do not allow water to pass through at all, it is impossible to install such a system.
However, in this case, you can drain the liquid directly onto the site or a specially dug ditch. In this case, it is better to choose a non-volatile sewer system with aeration. The principle of operation is approximately the same. The first tank must contain air so that aerobic bacteria can live and work. In the next compartment, the sludge settles and is transferred back to the first tank by a compressor. And in the third chamber, the water is finally purified and pumped into a ditch or onto the ground, from where it evaporates.
Life modern man filled with a variety of items that provide comfort and convenience. These include water supplied to the house, bathroom fixtures, and a toilet.
But such comfort systems, if they are not part of common system, the presence of which is possible in urban apartment buildings, need an individual cleaning system waste water and waste. Previously, people made do with an ordinary sewage pit, from which the flowing masses were absorbed into the soil, and when they accumulated excessively, they cleaned the ditches with the help of special machines, or the pit was simply moved to another place.
The disadvantage of this method of getting rid of sewage was the saturation of the soil and even water wells with pathologically dangerous microorganisms, which, as a result, became the cause of many diseases in humans and animals. As well as contamination of the land and rendering it unsuitable for agricultural use.
In order to protect the earth and people from dangerous microorganisms, wastewater treatment systems were invented; our company has been installing such systems for many years.
The cheapest and easiest to install treatment option today is a septic tank, which is a complex single-section or multi-section structure that provides partial purification of wastewater and its absorption into the soil or partial drainage. At the same time, the septic tank provides for ground filtration, in which the liquid passes through layers of soil; this requires good drainage properties of the soil and a considerable field of drainage action.
Installing a septic tank on clay soil
Many people, in order to save money, use septic tanks and install them in clay, but such a solution is simply a waste of money and labor. Whatever myths circulate around septic systems, they are intended for sand or other types of soil that can quickly absorb liquid.
They are not suitable for clayey environments due to poor drainage of this type of soil layer - our experts always explain this to the owners of clayey areas, but they do not always listen and drive themselves into unnecessary waste. The recent case of a septic tank in clay became a striking example of the irrelevance of such treatment equipment for clayey areas.
People contacted us due to a malfunction of the septic tank; when opening the pit, our specialists discovered a completely deformed container, completely unsuitable for cleaning anything.
Why do septic tanks installed in clay become deformed?
The septic tank itself is not capable of absorbing large amounts of water, since it is designed for low-volume drainage; in addition, it requires good drainage, that is, so that part of the purified water goes into the soil.
It is not typical for clay to absorb liquid, and this leads to the accumulation of liquid around the septic tank or complicates the work for drain pipe, and that, in turn, simply cannot accommodate the amount of liquid designed to pass through the soil layer. This puts pressure on the body of the cleaning device and causes it to deform.
Due to the impassability of the soil, the water simply crushes the septic device. An additional destructive factor is such a feature of clay as frost swelling, in which winter period the clay soil itself begins to put pressure on the septic tank and either pushes it out or deforms it if it is securely fixed.
Making surface drainage of water is also not relevant, since the septic tank does not completely purify liquid masses and discharging such water into a ditch or reservoir threatens the spread of harmful bacteria, and therefore promises environmental problems.
What to do if the septic tank is deformed?
Many people who have experienced the failure of a septic tank installed in clay blame the manufacturers of the septic system or the people who carried out the installation. At the same time, unfortunate owners again order and install a similar treatment system, and after short time again they get the same result.
The only solution to this problem, as practice shows, is to replace the wastewater treatment system with an option that is suitable specifically for clay. The most practical solution for non-absorbent soil, a biological treatment station is considered, which is relevant for any type of soil.
This is exactly the decision our specialists made when they pulled out the above-mentioned deformed septic tank from the ground, and it turned out to be the only correct one.
The thing is that the operation of a septic tank is based on absorbed soil and an extensive filtration field, for which clay cannot act as a field of action because it does not allow water to pass through. The waste pipe of the equipment is not able to do the work for the soil, that is, to let such a large amount of water pass through, in this case, the septic tank itself is deformed if it is made of not durable materials, such as polypropylene, or the pipe ruptures if the body of the cleaning device is made of concrete mixtures.
Features of the biological treatment station
The main advantage of the biological station is that it is suitable for any type of soil. It differs from a septic tank and high level purification, which is about 98%. In fact, any impurity, thanks to special microorganisms on the influence of which the operation of the device is based, is converted by this installation into two types of useful raw materials: clean process 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, without any environmental indicators being violated. The resulting solid raw material can be safely used to fertilize the soil and plants. The following features of a biological station can also be called important:
- Compact, since such a cleaning device does not take up much space;
- Tightness and strong structure, in which the entry of sewage into the soil or water bodies is completely eliminated;
- Duration of operation, which can reach more than 50 years;
- Possibility to use the raw materials obtained after purification for technical purposes.
Principles of installing a septic tank
The septic tank is simplest form treatment facilities, 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 characterized by complete purification of liquids, such a device should be located no closer than twenty meters from a residential building.
An additional condition for installation is the location of the well or well with drinking water, the distance between it and the septic installation should be no more than 50 meters.
For clay soils, which have low drainage rates, but are considered an excellent environment for the spread of coliform bacteria, this distance can be figuratively increased to 80 meters.
The principle of operation of a septic tank is based on settling waste, so its capacity must be designed for a three-day norm of liquid waste so that it has time to settle. In clay soil there is no possibility for repeated ground filtration, and when settling, the liquid does not drain well due to the strength of the clay, which makes the relevance of a septic tank in clay a common myth.
Principles for installing a biological treatment plant
Biological sewage treatment plant is smaller in size because it does not involve a long-term settling process. Unlike a septic tank, in which waste liquids must stand idle for three days, this device allows you to clean the raw materials in a time not exceeding several hours.
At the same time, there is simply no need for additional ground filtration, because wastewater is processed and purified through the action of biological organisms (bacteria), for which the 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 sealed and made of durable materials, so for installation you don’t have to move the treatment station a long distance from the living room, and since the waste after such purification is safe, you don’t have to be afraid of the installation’s proximity to a well or water pipes.
Another advantage of this cleaning equipment is that it does not require insulation, since it operates from the network and provides for preheating.
What should you choose?
Some owners of clay areas still prefer to use more cheap septic tank, instead of biological system cleaning and looking for options for its correct installation.
Many not entirely conscientious experts suggest additional securing of the septic tank in order to prevent it from being pushed out during frost. It is often recommended to install a septic device near the surface to ensure at least partial drainage and filtration by the top layer of soil. At the same time, to enable operation, the device is insulated with the help of additional materials.
All these methods are good only in theory; in practice, any of them will soon lead to the destruction of the septic tank and problems in the autonomous sewer system.
If the site is endowed with clay soil, the only way to provide high-quality wastewater treatment is a biological treatment station, without which it is simply impossible to make an autonomous sewer system located on clay soils safe.
It just so happens that our comfort and additional amenities often become the cause of pollution. environment, this especially applies to places with clay soil. In order not to harm the environment, every owner of private sewer systems simply must take responsibility for wastewater treatment.
Saving in the form of a septic tank would in this case be a wrong decision, threatening unforeseen consequences; therefore, preference should still be given to a biological treatment plant.
Choosing a septic tank for clay soil and installing it are complex tasks that require 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 arranging an autonomous sewer system, these features must be taken into account.
Why do septic tanks installed in clay become deformed, and how to avoid this?
Most often used when installing septic tanks plastic containers large volume. 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, plates, 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.
What septic tanks can be used in clay?
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 classical multi-level systems should be abandoned. There are several options for autonomous sewers that can be used effectively.
Storage containers
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:
- concrete rings;
- wells lined with brick;
- large metal barrels;
- plastic containers, etc.
Such a septic tank for clay soil is an analogue cesspool and requires systematic pumping out of accumulated wastewater using a sewage disposal machine.
With soil purification
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.
For biological treatment
Closed septic tanks with biological treatment are very popular among owners of sites with clay soils. Such systems are autonomous sewerage stations. They give high degree 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.
Design features of a septic tank for clay
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. This problem especially often arises 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 executing earthworks When installing an autonomous sewer system, all safety measures must be observed, since 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.
Features of installation on clay soil
When planning to install a septic tank on clay soils, you must comply sanitary requirements 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 contamination of drinking water by wastewater.
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 tied reinforcement mesh required for pouring the concrete base. If necessary, a wooden or metal sheathing is formed 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.
Installation of local sewage treatment systems (septic tanks) is often complicated by mining and geological conditions (soil composition) and high groundwater levels.
These reasons create problems with the discharge of treated wastewater into the ground. The most difficult thing is to install 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%) belong to soils prone to frost heaving. It is because of this reason that the installation can be squeezed onto 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 for this, which encircles the septic tank and is attached to concrete base in the pit.
Considering that on clay soils drainage systems(filter fields) in many cases only work in upper layers soil, you have to resort to shallow placement of a septic tank.
In this case, it is necessary to provide measures for insulating the structure:
Insulating a septic tank with glass wool
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- In the simplest case, they resort to pouring an additional layer of soil above the topography (forming a mound above the installation site of the septic tank).
- It is more effective to insulate the treatment plant with special heat-insulating materials, the choice of which is quite wide. The most affordable (cost) method is filling the container with expanded clay. The use of polystyrene foam (preferably extruded) or polyurethane foam is considered more effective. In addition, active protection systems against exposure are increasingly being used. negative temperatures. To do this, use a heating electrical cable, the thermal power of which will reliably protect the septic tank from freezing even in harsh climatic conditions.
Discharge of treated wastewater
The main problem for those who decide to install an autonomous sewage system and install a septic tank in clay soil is the difficulty of discharging treated wastewater. Such soil has minimal filtering capacity, which creates a whole series sometimes intractable problems.
There are several main ways to remove treated wastewater from a septic tank in such conditions.
It is used if the soil on the site does not accept water at all. In this case, the entire volume of treated wastewater enters a sealed container or well, from which it is then pumped out using sewage disposal equipment or drainage pumps.
The disadvantages of this method include the need to construct a large-volume container, otherwise pumping will have to be performed very often. But if there is no other way out, this technology has to be used.
Increasing the drainage area
There are several varieties of this technology, but they all boil down to the need to increase the filtration area in order to ensure the removal of the required volume of treated wastewater even with minimal drainage capacity of the soil.
- Construction of a number of sequential drainage wells, in which case it is necessary to use rings of the largest 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 capacity of wells, they resort to drilling additional drainage wells. This method allows, in some cases, to reach filtering soil horizons, which will help to significantly increase the productivity of the structure. Drilled wells must be protected with casing pipes, and the simplest equipment must be installed at their mouth strainer, which will prevent silting of additional drainage.
- Install a septic tank in clay with your own hands It is also possible with the construction of filtration fields of a large area. This method is used at high GWL (groundwater level).
The most productive is a drainage system using corrugated plastic pipes and geotextiles. Pipes of this type are characterized by increased strength; they are able to provide effective removal of treated wastewater. And geotextiles prevent siltation of the system.
To increase the efficiency of the filtration field, laying two-level drainage is often used. In this case, a number of lines (drains) are laid close to the surface, and the main part is buried as deep as the groundwater level allows.
The filter line is laid in pre-prepared trenches, which are covered with geotextile fabric. Lay the drainage pipes. They are also covered with a layer of crushed stone on top, which can significantly increase the volume of discharged wastewater. The entire resulting system is covered with geotextiles, which will ensure the durability of the line.
To ensure filtration of wastewater in clay soil conditions, it is necessary to lay out filtration fields of significant area.
Of course, installing septic tanks in clay involves a significant increase in the volume of work performed during installation. But to provide effective work installations of local wastewater treatment even in such conditions is quite possible.
