How septic tanks work: device and types of treatment systems. What is a septic tank and how to choose it correctly? What are septic tanks for sewerage

In the memory of the majority, there was still an idea of a dacha as a miniature building on the same site, and there was not even a question of any amenities. But life does not stand still, progress has touched all areas, and, accordingly, the dacha is now radically different from the one that was 10 years ago.

In the modern view, the dacha is quite comfortable housing, sometimes even city apartments lose in terms of amenities and comfort.

Often in cottage and holiday villages centralized water supply and sewerage systems are not provided, but their presence is mandatory for comfortable living. Therefore, in order to provide themselves with all the normal conditions of stay, the owners are building an autonomous water supply and sewerage system.

A treatment plant in a private house is a septic tank, which, unlike the city sewer, is autonomous, that is, it has its own for each house.

From a practical point of view, the most suitable option for a sewer system for a private house is a septic tank.

Helpful information ! Now local sewage treatment systems have such a different look and design that the most modern and expensive ones are completely autonomous stations allowing to achieve almost complete wastewater treatment.

It is this diversity that gives rise to a lot of thoughts about choosing a particular model of a septic tank, and some even think about making it with their own hands.

What is a septic tank?

A septic tank is one of the components of an autonomous sewage system, which is a local installation.

It is designed to collect, settle and further treat all domestic household wastewater. A septic tank is usually installed where there is no possibility of connecting to a centralized sewerage system, that is, summer cottages located far from the city.

It is important to remember that a septic tank is just a type of local sewer system that has several options:

The most primitive type of septic tank is the usual storage tank. This type of sewage is an analogue of a cesspool, but somewhat improved. Due to the fact that the container is sealed, its contents do not pose a threat to the condition environment, and this is a definite advantage. From significant shortcomings it can be noted that constant monitoring of the filling of the container is mandatory, and regular pumping out of the contents too.
For private country house The most suitable option, both practical and effective at the same time, is a septic tank that allows both the collection and treatment of wastewater. The septic tank is not able to completely clean the drains, therefore, filtration fields are used for post-treatment.
The maximum degree of purification is possible in the presence of VOCs - local treatment plants that use biological methods of wastewater treatment. All VOCs have a forced aeration system and operate from the electrical network, therefore they are installed only in the area where the power supply is stable and uninterrupted.

Choosing a septic tank for a summer residence is by no means an easy task, because for each individual house you need to choose exactly the model that will most effectively cope with the disposal of wastewater.

What is the principle of operation of a septic tank

In order for the septic tank chosen for a country house or dacha to work properly and subsequently there would be no problems with its operation, it is necessary to have an idea of what scheme it works. Knowing this, you can select a number of parameters, based on which you need to choose the appropriate type of septic tank.

Regardless of the type of septic tank, the first thing you need to know is that any of its varieties is a sealed container with several chambers, the number of which depends on the specific model. The principle of operation of different modifications is practically the same and is the following scheme:

Passing through the sewer pipes, all effluents enter the first chamber, where primary settling takes place. In this phase, all heavy inclusions settle to the bottom of the tank, and light fractions (including fats) rise to the surface of the entire thickness. All the gases formed during the decomposition of wastewater exit through the ventilation.
In the second chamber, the settling of waters clarified in the first chamber continues. They get here by overflow. With the help of special bacteria, in the second chamber, the masses are cleansed of the organic origin of inclusions.
The process of settling in the last chamber is completed, then the purified water is discharged to the filtration fields, where the purification from the impurities remaining in the water occurs when the water passes through the soil. If the septic tank has a deep cleaning filter (biofilter), then there is no need to build filtration fields.

The device of a septic tank in a private house, selection by characteristics

When choosing a septic tank for a summer residence, based on its technical characteristics, you need to consider the following points:

The resulting average daily volume of effluents. This parameter depends on the number of people permanently residing in the house, as well as the presence various installations and technology, sanitary purposes. It is important to remember that more wastewater is generated in such houses where a water-consuming system is installed. Appliances(dishwasher and washing machine), car washer, garden irrigation system, and bathtub. If the house has only a sink and a shower, it is spent in order less water, and, accordingly, less waste is also formed;
The level of groundwater, as well as the nature of the soil, determines the need for arrangement of filtration fields, as well as their impact on the state of the environment;
Time or frequency of people living in the house (permanent place of residence or use of the house only for occasional rest);
The material costs included in the estimate for the acquisition of VOCs.

Homemade or factory made?

Analyzing specifications different types of septic tanks, including home-made ones, can take a very long time to choose, especially if the characteristics are similar.

But, if we take into account the low cost of a home-made septic tank and the fact that, according to popular opinion, it is not inferior to a purchased one in terms of efficiency, before proceeding with the construction, it is necessary to familiarize yourself with all its pluses and minuses.

For self-manufacturing septic tank can be used the following materials:

Concrete (rings or monolith);
plastic barrels;
Old car tires.

Each of these types has certain features that you should definitely take into account.

A septic tank made of concrete, whether monolithic or from rings, needs a mandatory internal and outdoor waterproofing. Otherwise, during long-term operation, the concrete will corrode, and the entire soil adjacent to the tank will “be saturated” with a rather unpleasant odor.

Another important nuance : construction concrete septic tank rigid, and therefore, with seasonal freezing and thawing of the adjacent soil, the integrity of the structure may be violated. The cost of this type of septic tank is quite high, and you will have to work hard.

Septic tank from car tires can be spontaneously depressurized at any time, and this is completely independent of the type and quality of the sealant used.

Equipping a septic tank from eurocubes or plastic barrels, it should be remembered that its volume is too small, and this type is suitable only for cottages and houses with a minimum amount of wastewater generated.

So, if the main criterion for choosing a septic tank is its low cost, then a septic tank made of tires or plastic barrels is the best option, but with some drawbacks.

Ready septic tanks

Comparing self-made septic tanks and purchased ones, we can say with confidence that ready-made ones have a lot of advantages:

Ease of transportation, which is due to low weight;
For loading, unloading and installation, you do not need to additionally involve special equipment;
The material from which the septic tank is made does not lend itself to the aggressive effects of any environment;
High-quality factory assembly, virtually eliminating the possibility of container leakage;
The possibility of flooding with groundwater or rainwater is completely excluded.

In addition to the advantages, ready-made septic tanks also have some disadvantages, and the same parameter can appear in both lists. Here, for example, the low weight of the structure, when the level of groundwater wastewater is raised, the containers can be shifted closer to the soil surface. This will entail a violation of the integrity of the entire structure of the sewer system.

Local treatment plants

Local treatment facilities are the most advanced, not only from the technical side, and have a lot of advantages, the main of which are:

Almost complete wastewater treatment (up to 95%), after which water can be drained to the ground surface;
Reliability.

Such systems do not need pumping, they are called so - a septic tank without pumping. The only drawback, in addition to the high cost of such an installation, can be called volatility.

Aerotank is a kind of modification of local treatment systems, providing a high degree of wastewater treatment with the help of aerobic bacteria. With the help of a compressor, oxygen is supplied to the installation, which is necessary for bacteria to effective work.

What is better?

And yet, which version of the septic tank should be preferred, ready-made or do-it-yourself? The answer just depends on personal preference. There are a lot of factors influencing the process of making this or that decision, but if we summarize them, the recommendations will look like this:

With limited material possibilities you can choose the factory version of the septic tank with a mechanical wastewater treatment system. If this is not affordable, then the only right option would be to build it with your own hands.
If financial costs are not the main selection criterion, and work efficiency and the degree of purification come to the fore, then best option in this case, a local treatment plant with a biological treatment function.

If the cottage or Vacation home does not have a connection to the central sewer, the question arises of what a septic tank is and how to make and mount it on personal plot. Many homeowners would like to arrange it themselves. After all, waste disposal using a conventional cesspool is not effective enough and has a number of disadvantages.

You need to understand what a septic tank is and how it works. A septic tank is a small sewerage system consisting of filters, a storage tank and a pipeline. A septic tank is a device for treating wastewater and then filtering it. After that, the water becomes suitable for removal into the soil or into a nearby reservoir.

Depending on the design of the septic tank for the sewerage of a private house, they differ in the method of cleaning incoming effluents, productivity, durability, etc. An important indicator is such an indicator as the frequency of cleaning the structure itself with the help of sewage equipment.

The accumulative septic tank is arranged quite simply. In this design, wastewater flows from separate sewer pipes into a collector, and from there into a special container. Here, biological suspensions settle, which subsequently decompose under the influence of special microorganisms. The main volume of waste liquid in such a system seeps into the soil, which is a natural additional filter for water purification.

The most effective is a 3-chamber sewer septic tank with natural wastewater treatment. Purification tanks in such a treatment system can be equipped in different ways. The material for the manufacture of storage tanks can be:

plastic;
stainless steel;

How does a septic tank work

How a septic tank works modern model, consisting of a pipeline and a treatment system, allows you to almost completely clean the wastewater and bring it into the ground without harming the environment.

From the sewer pipes located in the house, the used water enters the 1st septic tank. Insoluble waste particles contained in the water sink to the bottom of the tank. Additionally, under the action of the fermentation reaction, organic substances dissolved in water are bound and, thus, wastewater undergoes primary treatment.

Then water containing small impurities is poured by gravity into the 2nd tank. The purification process here takes place in the same way as in the 1st tank, taking into account the fact that the amount of impurities in the water is less, and therefore the biological purification process takes longer.

After repeated purification and clarification, the effluents are poured into the 3rd tank. If it is a sealed container, the water, after settling through the drainage pipes, moves to the filtration area of the earth. Being distributed evenly over it, the effluents pass through a specially equipped cushion of crushed stone, sand or other bulk material. Then the purified water is absorbed into the soil. If the 3rd tank is made drainage well, a pillow made of bulk material is settled in the bottom of the well, the walls of which can be lined with bricks.

After clarification and settling, the water flows into the aeration field. Here it is filtered as it percolates through the soil. Additional cleaning while providing bacteria and other microorganisms that live in upper layers soil.

preliminary calculations

The defining moment in arranging a septic tank with your own hands is the correct calculation of the required dimensions of this device and compliance technological requirements during its construction.

A key factor in determining the required size of a septic tank is the amount of wastewater generated during the use of plumbing devices within 3 days.

According to average statistics, when using plumbing, 1 person produces approximately 600 liters of waste water within 3 days. Multiplying this number by the number of households, and adding a little for insurance, you can get the value needed to calculate the volume of the septic tank. It turns out that the required volume of a septic tank for a family of 3 is about 2 m³. If for some reason it is difficult to install a treatment system of sufficient volume, the cleaning efficiency can be increased with the help of special aerators - systems that saturate wastewater with oxygen.

Aeration septic tank

Aeration septic tank, what is it? At its core, this is a conventional 2- or 3-chamber sewage sump, the efficiency of which is increased by the use of aerators. In an aerobic septic tank, water passes through 2 or 3 tanks, in which hard particles gradually settle. In the last chamber, the effluents are cleaned with the participation of oxygen. Water enters the soil almost clean and suitable for irrigation. It is possible to discharge such water into a nearby reservoir with running water.

The disadvantages of such a septic tank include the need to purchase an aeration system, as well as the installation of aerator power supply circuits. The electric power consumed by the aerator is small, but like any electrical device, the aerator requires periodic inspection and maintenance.

Production of a sewer system

A concrete tank for a septic tank can be made from concrete rings or in the form of a well or pit, lined with concrete from the inside. This well or pit is usually divided by partitions into 2 or 3 compartments. In addition, it is necessary to equip an aeration site for secondary filtration of incoming effluents.

A septic tank made of concrete rings is equipped to a depth of no more than 4 m. The diameter of a concrete ring is from 70 to 200 cm. The ring weighs about 0.6 tons. A truck is needed to deliver concrete rings to the local area. On the site of the ring, you can roll to the construction site of the septic tank.

If it is impossible to use heavy construction equipment, the installation of a drain well can be carried out by gradually immersing the concrete ring into the ground. Having installed the ring in the selected area, you need to gradually remove the soil inside the ring, while the ring will descend into the well. Gradually, the upper edge of the concrete ring will be level with the upper edge of the soil. Now you need to install the next ring on top of it. Align it and fix it with special spacers or fittings welded from the inside.

Upon reaching the required depth of the well inside the rings, it is necessary to equip concrete bottom. The joints between the rings must also be sealed with concrete mortar. After that, dividing partitions are made and installed inside the drain well. You can also dig a pit required size, build a formwork inside it and pour concrete. The formwork is then removed.

Necessary components for a septic tank

To equip an effective local sewage system - a septic tank, you will need:

tanks made of plastic or stainless steel;
sewer pipes through which sewage will pass;
hatches through which free access to each chamber will be provided;
pipes for arranging ventilation risers that serve to remove gases arising from the fermentation of wastewater;
a pump of a special device for removing purified water from the last chamber.

When arranging a septic tank without using ready-made tanks, the following materials will be needed:

concrete mortar or concrete rings;
concrete plates;
boards for formwork assembly;
geotextiles for sealing;
crushed stone or other bulk materials for arranging the filter layer;
cable or steel tape.

To build a septic tank with your own hands, you need to prepare the following tools and devices:

tank for mixing concrete;
construction mixer or electric drill with a whisk attachment;
measuring container for measuring the components of the concrete solution;
construction roulette;
shovels - shovel and bayonet;
construction scissors and / or a sharp knife;
plumb and level;
welding machine for welding pipes;
saw;
work clothes;
rag.

Arrangement of a septic tank from a finished tank

Under a septic tank from a eurocube or other ready-made tank, it is also required to dig a pit. Settling chambers are pre-connected with overflows for free passage of water. Then the whole structure is placed in the finished pit. Additionally, it is necessary to equip the passage of water from the last tank to the aeration section.

It is advisable to purchase chambers for a septic tank with corrugated walls. In this case, the required wall thickness should be about 0.7 cm.

To install the tank, you need to dig a pit. Its value is determined by the size of the purchased capacity. On each side, you need to add another 20-25 cm.

When the pit is ready, a concrete slab must be placed at the bottom. Then the tank must be filled with water and placed on the bottom of the pit. The septic tank is attached to a concrete slab with a special cable or steel tape. This will prevent the reservoir from extruding to the soil surface. You can pour a cement-sand mixture into the pit (ratio 1 x 10) or pour a solution prepared according to the usual recipe.

Septic tank from eurocubes

Eurocube is a special cube-shaped container designed for storage and / or transportation of liquid and bulk materials. Since for the manufacture of such containers is used enough reliable material, they can be successfully used in the arrangement of septic tanks.

Under a septic tank from eurocubes, it is necessary to prepare a foundation pit in a similar way. A concrete layer with a thickness of at least 20 cm is poured to the bottom. Then a eurocube is installed in the pit. Branch pipes are mounted to it - inlet and outlet. Then water is poured. The lid closes hermetically. After that, the free space in the pit is filled with a concrete solution.

Septic tank

A septic tank in the form of a well is dug in the same way as a cesspool. Then it is connected to the filter tank or filter field.

The filter tank is equipped with reinforced concrete rings. A pillow of bulk material is poured at the bottom to filter wastewater.

In the walls of the filter tank, it is necessary to equip the outlet openings. The total area of these holes should be 10% of the area of the walls of the filter container. The average diameter of each hole is from 4 to 6 cm. A filter layer of bulk materials must be poured around the walls of the container.

Filtration area

To equip the filtration area, it is necessary to lay a distribution pipeline from the septic tank. Pipes with a diameter of 10 cm are laid with a slight slope.

An irrigation system of pipes with a diameter of 10 cm is connected to the distribution pipeline. Inspection wells are equipped at the junctions of distribution and irrigation pipes, or pipes are brought out to a height of up to 40 cm above the soil level.

Irrigation pipes are laid at least 1 m above the location of groundwater. In this case, the pipes should pass 80-120 cm below the freezing level of the soil. In irrigation pipes, it is necessary to drill small holes (diameter - 5 mm), directed into the depth of the soil at an angle of 60 °. They are staggered every 5 cm.

Before installing the pipes, it is necessary to fill and level the bulk materials for the filter. The required layer thickness is 2 cm, width is 2.5 cm. The pipes must be immersed in bulk material by 0.5 diameters.

The ends of the irrigation pipes are equipped with risers, which must be brought out 2 m above the soil level. The required diameter of the riser is 10 cm. Air will pass through the risers, providing aerobic wastewater treatment.

Rules for installing a septic tank

Sewerage septic tank requires compliance with technical standards during installation. A sealed storage septic tank without an aeration site can be installed at a distance of at least 5 m from the house and other buildings. When creating a septic tank from 2 or 3 chambers, remember that each next tank must be located below the previous tank. The filtration field is located below everything, during the construction of which the septic tank must be removed from the house or an open reservoir by at least 30 m. In this case, the septic tank must be located at a distance of at least 50 m from the source of drinking or technical water supply.

For the arrangement of each settling tank, 1.5-3 m² of area is required. The average size filter field for a family of 4 - 30 m².

Geotextiles for sealing a septic tank can only be used of a thermally bonded type. Needle-punched geotextiles will quickly become overgrown with silt and become unusable.

There should not be any buildings or vegetation on top of the filtration field. Only the arrangement of a flower bed or a lawn is allowed, on which it is desirable to plant only lawn grass and small flower crops.

Improvement of a country house or cottage in the absence of nearby centralized sewerage networks is carried out using autonomous systems, one of the main elements of which is a septic tank. It is in this container, consisting of one or more chambers, that wastewater is collected and subsequently treated. The more complex the device of the septic tank, the more effective the purification of the sewage that enters it. When choosing a finished design treatment plant the daily volume of waste is taken into account. This value is affected by the number of residents permanently residing in the house, as well as the presence and intensity of operation of plumbing equipment. Any type of septic tank must provide a sufficient degree of wastewater treatment for their further removal into the ground without the risk of contamination. If desired, the owner of the house can pump out the septic tank by calling a sewage truck for this purpose.

In the video, as an example, the principle of operation of the Topol septic tank is clearly shown:

How is septic tank treated?

Wastewater, entering through the drain sewer pipe into the first chamber of the treatment plant, breaks up into separate fractions. Large solid particles fall to the bottom, and smaller suspensions, along with water, enter the second chamber, where they are “attacked” by special anaerobic bacteria. In both chambers, fermentation processes are actively going on, as a result of which methane gas is released.

The entrances to the individual compartments of the septic tank are closed with a gate formed by the flow of water, which prevents the spread of unpleasant odors around the treatment plant. A special removable filter is installed in the third chamber, which catches leaked dirt from the first two compartments. Here, aerobic bacteria enter the struggle for clarification of wastewater, the vital activity of which is possible in the presence of oxygen. This is how it is possible to describe the principle of operation of septic tanks manufactured by both Russian and foreign manufacturers.

Finished models of septic tanks manufactured by Russian and foreign manufacturers are lowered into a prepared pit. Effluent treated as a result of a three-stage treatment enters the filtration field and goes into the ground

Important! As a result of multi-stage treatment of sewage waste, they are effectively cleaned. The treatment plant itself is able to function longer without maintenance and pumping out by special equipment. The sanitary condition of the site depends on how the septic tank works. With high-quality cleaning near the structure, they never appear unpleasant odors having a specific aroma of the existing sewerage.

Benefits of using septic tanks

Why use this particular treatment facility? And here's why:

the possibility of the maximum possible purification from harmful substances sewer water;
operation of structures in any climatic conditions, including low temperatures in winter;
no need for frequent pumping;
long service life of the treatment plant;
independence of some models of septic tanks from power supply.

The principles of creating a homemade septic tank

Septic tanks are presented on Russian market in a large assortment. Ready-made tanks, oriented in a horizontal or vertical position, are easily installed in a pre-dug pit. These containers can be made from durable materials capable of withstanding aggressive environments. Typically, manufacturers produce products made of plastic and fiberglass, but there are also models made of metal and reinforced concrete structures.

The cost of finished septic tanks is quite high, so many owners of private houses, cottages, summer cottages are engaged in the installation of single-chamber or two-chamber septic tanks with their own hands. At the same time, a trench is dug manually or with the help of a tractor, into which concrete rings are lowered and connected by an overflow pipe. As a rule, such installation of a treatment plant requires the application of physical effort, but not finance. This is how an approximate diagram of a home-made septic tank, built from three to six concrete rings, looks like.

In the first well (sump), a concrete bottom is necessarily poured, which does not allow dangerous bacteria to penetrate into the soil. In the second well, the bottom base is covered with layers of sand and gravel, necessary for filtering the effluent that enters in a purified form from the sump.

Schematic arrangement of a three-chamber septic tank made of concrete rings in the form of three wells. In the first and second wells, liquid waste is purified, and in the third, they are discharged into the ground

Important! To ensure waterproofing of the construction of a homemade septic tank, the seams between the rings are coated cement mortar and additionally treated with special water-repellent mixtures.

Knowing how a typical septic tank is arranged, and on what principle its functioning is organized, you can always build such a structure with your own hands from available materials.

septic tank (sump) - element of the local treatment plant; applied at the design and construction stage complex systems local treatment of household and household wastewater. A septic tank, as such, is not a complete treatment plant and is used in accordance with current regulations and rules. During the operation of the treatment plant, it is necessary to use methods of soil post-treatment.

The septic tank is designed to collect and treat household wastewater from individual residential buildings, low-rise buildings, cottages in the absence of a central sewerage system. The operation of the septic tank is based on the principle of gravitational settling and biological post-treatment using bioenzymatic preparations, as well as soil natural and forced post-treatment methods. These can be biofilters or bioloading.

In Russia, the guidance for the design, construction and operation of septic tanks is the Code of Rules 32.13330.2012 “Updated edition of SNiP 2.04.03-85“ Sewerage. External networks and facilities“.

Encyclopedic YouTube

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Subtitles

In this video, we will talk about the features of wastewater treatment systems, the advantages and disadvantages of various types of septic tanks, and also try to answer the question: how can you still choose the most optimal local sewage system for yourself? But before continuing, I would like to introduce the sponsor of this issue - the Praktika company. The Praktika company is the market leader in inspection hatches in Russia. The company manufactures and sells inspection hatches under the trade name Praktika hatches. Inspection hatches are access devices to engineering and plumbing communications. They are installed on the floor, in walls and ceilings and are designed for cladding with various finishing materials, including any kind of ceramic tiles and mosaics, as well as for painting. Very often, inspection hatches are also called sanitary hatches, since they are installed in bathrooms and toilet rooms, for easy access to plumbing fittings, water meters, boilers and other utilities. And the most important thing! After finishing, such hatches are absolutely invisible! I recommend, the link will be at the bottom in the description of the video. So, there are two ways to treat wastewater: The first is an anaerobic method. With this method, wastewater treatment occurs due to anaerobic bacteria that do not require air access. With the anaerobic method, the degree of purification can reach about 70% and therefore the water at the outlet of sewer plant additional cleaning is required. And for this, filtering fields are used. The second is the aerobic way. In this case, wastewater treatment occurs due to aerobic, i.e. air-requiring bacteria. With this method, due to forced air injection, a faster process of polluted water splitting occurs, which makes it possible to achieve a purification rate of over 95%. The first method is used in various types of septic tanks - from simple overflow septic tanks made of concrete rings to local treatment facilities. The second method of purification is used in autonomous sewage systems - for example, deep biological treatment plants. Consider a septic tank made of concrete rings. This type of local treatment plant, operating on an anaerobic principle, despite its simplicity and low cost, nevertheless, requires a thoughtful approach. Although a similar type of treatment plant is often built independently on the site, a number of features of this type of septic tank should be taken into account: Purification in this type of septic tank occurs by overflowing wastewater from chamber to chamber. And therefore, as a rule, 3-chamber septic tanks are installed from concrete rings. It is necessary to pay attention to the diameter of the rings. The volume of the septic tank depends on this. The larger the number of people living, the more the volume of the septic tank and the number of cameras are needed. If the site has a high groundwater level, then in order to avoid seepage of contaminated water into the soil, better sealing of the septic tank is required. For better purification of wastewater, special bacteria can be used, and for post-treatment of wastewater, it is recommended to arrange a filtration field. The disadvantages of this type of septic tank include: The complexity of installation and large volume earthworks; Also, unlike plastic septic tanks, complete tightness of the joints of the rings is not ensured here; And although this septic tank can be dumped toilet paper, personal hygiene products and to drain from the washing machine, then the discharge from the dishwasher is no longer desirable, because. fatty deposits form on the walls of the main pipe. It should also be noted that it is impossible to use water for irrigation, and the need to periodically call a sewage machine to pump out a septic tank. Let's move on to local treatment facilities. If we talk about the principle of operation of septic tanks, we can say the following. Wastewater from household appliances is directed by gravity through pipelines to the first chamber of the septic tank, where it is naturally separated into light ones - these are fats, oily substances and organic waste and heavy components. Heavy fractions sink to the bottom and eventually turn into silt, while light fractions, along with water, enter the second chamber for oxygen-free processing by anaerobic bacteria, and then, if any, into the third chamber. And the final treatment of wastewater is already carried out in the filtration fields, selected based on the absorbent characteristics of the soil at the site and the depth of groundwater during installation. Organic sludge accumulated in the septic tank intake chamber as a result of the processing of heavy fractions from wastewater is periodically disposed of by pumping through the sleeve of a sewage machine. It should be noted that for this type of septic tank, a mandatory filtration field is required, since the water after the septic tank is cleaned by about 60-70% and it requires additional treatment for discharge into the ground. After the process of additional purification, the water is purified to almost 99%. However, it is not recommended to use these drains for irrigation or other needs. For seasonal living, pumping is required once every 1-3 years, depending on the number of people living and the intensity of use. This can be assessed by visually opening the manhole cover in the septic tank before the winter period. And with permanent residence, using the filling of special bacteria for intensive decomposition of the sediment, approximately once a month, pumping is required much less frequently, only once every 5-8 years. At the same time, the septic tank can be used for any soil types, including non-filtering and high groundwater levels. The main advantages of this type of treatment facilities include: Long service life - more than 50 years; Ease of operation and energy independence; A plus is also the possibility of processing in moderation organic substances that enter the septic tank along with drains, for example, detergents , paper or cigarette butts; And finally, the durable ribbed surface of the septic tank, and its manufacture from especially durable plastic, increases resistance to aggressive chemicals and seasonal temperature changes. Now what is a deep biological treatment plant? The principle of operation of the station is based on the method of continuous cultivation, that is, the cultivation of microorganisms, which occurs under the influence of oxygen, or as it is also called the aeration method. And the purification of wastewater occurs due to activated sludge, which is obtained from bacteria and microscopic animals. Activated sludge is an active biomass suspended in water that carries out the process of wastewater treatment in a tank. A large number of microorganisms formed during biological treatment intensively oxidize organic substances. Thanks to the organic substances in the wastewater and the excess oxygen entering the plant, these bacteria begin to develop rapidly and then stick together into flakes, after which they secrete enzymes that mineralize organic pollution. When it enters the outlet sump, sludge with flakes quickly settles, separating from the treated water. The degree of wastewater treatment allows the use of purified water for irrigation, and the activated sludge formed in the aeration tank is very similar in structure to river sludge and is a valuable fertilizer. So you don't have to call a sewage truck. Unlike cesspools, in a biological treatment plant, sewage is not accumulated, but biochemically decomposed into simple, safe compounds - technical water and stabilized activated sludge, therefore, there is no bad smell. Therefore, the station can be installed near the house, at a distance of 2 meters, and the purified water can be immediately diverted to the terrain without the use of soil purification systems. Despite the reliability of the system, there are a number of rules that must be followed for the efficient operation of the installation, namely: it is forbidden to dump construction waste, chemicals, polymeric materials, oil products and other non-biodegradable compounds into the sewer. And in the event of a power outage, it is necessary to reduce water consumption, as it is possible to overflow the receiving chamber of the station and ingress of untreated waste into the environment. It is also necessary to produce timely pumping of activated sludge. Summing up, it can be noted that the main advantages of such a system are: High degree of purification, which in modern aeration installations exceeds 95%, and purified water can be sent to water bodies without additional filtration fields; The station is easy to transport. Also, when installing the station, it is not required to carry out large-scale earthworks or install the station on a concrete base and anchor it; The mechanical properties of the body made of foamed polypropylene allow you to install the station in any, the most "heavy" soil, even at a very high level of groundwater; The advantages also include the durability of the station, its absolute tightness, environmental safety, resistance to corrosion and the effects of aggressive acids and alkalis. The deep biological treatment system can be operated for at least 50 years. In order to choose a local treatment plant, first of all, you need to answer a few simple questions: How many people will live in the house permanently; What type of residence will be in your house - seasonal or permanent; How many plumbing fixtures form drains; Land area; And the features of the soil in which the treatment plant will be installed. Knowing that the city water consumption rate is 200 liters per person per day, everyone can choose the required volume of a local treatment plant for their home. An important influence is exerted by: the location of the septic tank on the site, the soil characteristics and the factor where the treated effluents will be discharged. Depending on this, the installation scheme of the septic tank and the corresponding additional equipment are selected. So for a classic installation scheme with a low groundwater level, infiltrators, drainage pipes or a well will be required, in accordance with how your filtration fields are organized. Gardeners need to remember that planting trees closer than 3 meters from the location of the septic tank is not allowed, especially those trees that have a very powerful root system. And if there are already wells or wells with water on the site, then the installation of a septic tank filter pad should be carried out at a distance of more than 15 meters from them. I hope this information will help you in choosing a septic tank and, as always, thank you for your attention. Subscribe to the channel. And all the best to you.

Device and principle of operation

The sump is a container consisting of a single hermetic body (concrete or plastic), divided, as a rule, into two or three sections (A, B, C), a pipe for supplying the initial sewage wastewater (E), and a treated water outlet (F) , blockers between sections.

SNiP 2.04.03-85, depending on the flow of wastewater, distinguishes:

single-chamber septic tanks - with a wastewater flow rate of up to 1 m³ / day;
two-chamber - up to 10 m³ / day;
three-chamber - over 10 m³ / day.

The first section (zone A) of the septic tank is directly connected to the inlet sewer line on one side, and on the other, through a blocker system (water seal) with the second section (zone B). Then through the blocker with the third section (zone C). Zone A serves as the primary septic tank for coarse sludge. In this chamber, the primary, rough cleaning of household wastewater entering the septic tank from suspended small and large particles is naturally carried out. Sand, small potato peelings, etc. settle at the bottom of the chamber (everything that can pass through the sink in the kitchen or in the bathroom). The second section of the treatment plant (zone B), the methane tank, acts as an anaerobic reactor. Here, the decomposition of chemical compounds formed as a result of the use of various detergents, personal care products and the decomposition of organic compounds of natural origin takes place. The third part of the treatment plant (zone C) serves as the final clarifier for domestic sewage. Through the final settling of suspended particles, clarified effluents reach a degree of purification up to 65% of the initial pollution level.

After passing through the septic part of the treatment plant, wastewater is sent to the soil aftertreatment. In cases where soil post-treatment cannot be performed: the groundwater level is too high (less than 0.4 m from the ground level) or an increased quality of wastewater treatment is required, a drip biofilter (bioseptic) is used.

at a wastewater flow rate of up to 5 m³ / day - at least 3 times the daily inflow;
at a flow rate of more than 5 m³ / day - at least 2.5 times.

Cleaning sequence

Household household wastewater from a residential building (structure) flows by gravity through a sewer pipeline into the receiving chamber of the septic tank - zone A of coarse sediment, where floating films, fats, surfactants and non-precipitating particles are retained. Non-settling substances floating on the surface of the water form a film over time. Larger or solid substances that enter with domestic sewage and can settle are screened out and accumulate at the bottom of the septic tank in the form of sludge. From the receiving chamber, the so-called. septic zone, domestic household wastewater through the blocker system enters the anaerobic fermentation chamber - zone B (methane tank).

For proper operation of the cleaning system in the septic tank, the bollard vias must be located below the level of the floating film, but above the level of the incoming sediment. The design of the structure must have a sufficiently tight housing. The presence of water seals and blockers at the inlet and outlet of the methane tank allows you to maintain a deficit of free oxygen in the septic tank, thereby ensuring an anaerobic process for cleaning household wastewater.

In the methanetank, in the reaction zone, facultative microorganisms work first, then methanogenic bacteria. The anaerobic process itself takes place in two stages:

acid fermentation stage: carbohydrates, proteins and fats break down into a series of lower fatty acids: acetic, butyric, formic and propinoic acids; carbon dioxide, hydrogen sulfide, ammonium, various alcohols and other organic compounds.
methane fermentation stage: fatty acids, alcohols, various organic compounds formed at the acid fermentation stage decompose to hydrogen, carbon dioxide and methane.

After cleaning in a methane tank, domestic wastewater enters the third section of the septic tank through a bypass - into zone C, where organic compounds, as a result of anaerobic processes (processes of processing organic and inorganic waste by bacteria into sludge), pass from a dissolved state to a suspended one, after which they precipitate. Then, from zone C, domestic wastewater enters the filter layers of the soil for subsequent, final post-treatment.

The most important factors influencing the activity of microorganisms are: the presence of organic matter in domestic wastewater; domestic wastewater temperature (optimally 10-35 ° C); access to the oxygen plant; runoff acidity; absence of toxic substances. The septic tank cleans domestic wastewater both with the use of bioenzymes and without the use of these preparations. The use of bioenzymes allows to sufficiently accelerate the decay processes organic matter and improve the quality of wastewater treatment.

Soil post-treatment

Mandatory when using a septic tank as an element of a treatment plant. The design of the soil treatment facility is determined by the detailed design and depends on the type of soil, the conditions for the discharge of domestic wastewater (the required quality of treatment), the level of groundwater, climate zone, terrain, site plan. The location of the treatment plant is determined at the design stage with an individual binding in terms of plan and height to the building site, subject to the availability of the following information and characteristics of the site: hydrogeological situation at the proposed location of the treatment plant, filtering capacity of the soil, the presence of karst rocks, the protection of the underground aquifer, standing height of groundwater.

In areas where the discharge of clarified wastewater without post-treatment is prohibited by sanitary standards, setting the filter field is required. The filtration field is a pipeline made of drainage pipes laid over a layer of crushed stone in the thickness of a sandy base. Water is filtered through the sand and enters the layers of filtering gravel, and then soaks into the soil. There is also the use of such post-treatment systems as: a filter well, a filter trench, a filter using activated materials, as well as ultraviolet disinfection lamps.

For soil post-treatment, it is possible to use the following facilities:

filtering well (FC);
absorbent trench (platform) (VT);
sand and gravel filter or filter trench (FT);
underground filtration field (PPF).

Arranged on filtering soils - sandy loam, sandy soils(FK, PPF) and non-filtering (FT) soils with a groundwater level of more than 1 m lower than the base of the well (FC), irrigation pipe tray (PPF) or drainage pipe tray (FT). The facility is supplied ventilation pipe D = 100 mm, which is brought above the soil surface above the expected level of snow cover (usually 0.7 m). Ventilation is placed on each irrigation (at the end of the line) and drainage (at the beginning) pipe.

The dimensions of the well and the length of the sprinklers are determined by the allowable hydraulic load - water consumption per 1 m² of the filtered surface (bottom and walls of the FC) or per 1 m of the length of the irrigation pipe (PPF, FT).

The drainage device, depending on the characteristics of the soil on the site, is divided into two main types of performance: filtering soil (sandy loam, sand, peat) or non-filtering soil (clay).

Filter well

A filter well is organized on the filtering soil, the filtration area for sandy loam is 3 m², for sand - 1.5 m² (calculated per person living in the house). The larger the filtration area, the longer the life of the well will be. For the system to work correctly, groundwater must lie below the level of crushed stone laying by 500 mm, while it is necessary that the base of the well be higher than the groundwater level by more than 1 m.

The filtering well is installed in sands and sandy loams from monolithic reinforced concrete, or prefabricated reinforced concrete structures or bricks. The bottom of the walls is filled with crushed stone, from the inside the well is filled with a layer of crushed stone up to 1 m high. The efficiency of domestic wastewater treatment in terms of suspended solids can reach 100%.

Absorbent trench (platform)

Where the discharge of domestic clarified wastewater after passing through a septic tank without a post-treatment system is not allowed according to construction and sanitary standards, an additional installation of an absorbent trench or platform is possible. The absorbent platform is a pipeline made of perforated material. Water passing through it enters the soil, then, passing through a layer of porous filtering soil, it contributes to the ideal development of natural bacteria.

The absorbent trench is used in sands and sandy loams and is a system of perforated irrigation pipes made at a depth of up to 0.9 m and more than 1 m above the groundwater level. The irrigation system is a perforated pipeline system laid with a slope of 0.001-0.003. To ensure rigidity at the base of the pipes, it is necessary to lay crushed stone under them, broken brick, gravel or slag fine fraction(20-40 mm). At the end of the irrigation system, it is necessary to make a ventilation riser (air) overall length not less than 0.7 m. The effect of possible cleaning in terms of suspended solids in the filtration fields is up to 98%.

filter trench

The filtering trench is carried out in soils with low filtering characteristics (loams and clays), making out artificially formed soil layers, in the layers of which drainage and irrigation networks are made. These trenches are recommended to be placed near trenches, inclined recesses, where treated domestic wastewater flows by gravity, or to arrange the pumping of incoming clarified wastewater through a water intake well. The space between the drainage and irrigation network is filled with rubble and sand. The difference between a sand and gravel filter and a filter trench is that the drainage and irrigation pipes placed in the pit are made in parallel lines.

Underground filtration field The filtration trench is placed along the slope of the terrain. The length of one line of the irrigation and drainage network is recommended to be no more than 12 m; slope in the direction of water movement 0.01. The configuration in plan (radial, linear, parallel) depends on the general layout and topography of the site, its size, existing and planned landscaping and landscaping. If the number of lines of the irrigation network is more than one, a distribution well is arranged, which ensures uniform distribution of wastewater along the lines. Parallel trenches are made separate (usually PPF in sandy loamy soil) or combine two or three lines of irrigation pipes in one wide trench, observing the distance between the axes. Under irrigation pipes, in a wide trench, one or two drainage pipes. After that, the filtered water flows into the drainage pipes and falls into a ditch or ravine.

Post-treatment filter

With special requirements for the quality of clarified domestic wastewater, additional biological treatment is used in the biofilter tank. Filtration materials: crushed granite, gravel, sand, anthracite, granulated blast-furnace slag, polymers, etc. The use of polymer filters, which have a good three-dimensional distribution and a large free volume - up to 90% (crushed stone is only 25%), allows you to treat wastewater more qualitatively.

Required specifications

A septic tank is a sealed container. A variety of materials can be used: composite fiberglass, polyethylene, polypropylene, reinforced concrete, however, you need to choose a material considering all its technical characteristics: tightness (reinforced concrete septic tanks have insufficient tightness, so that this drawback does not cause inconvenience, they use waterproofing from the inside and outer side), susceptibility to corrosion (metal and reinforced concrete containers have this disadvantage), mechanical resistance to soil pressure, or strength (polypropylene containers have a lack of strength, despite the stiffening ribs on the body). It should also be noted the advantage of sectional septic tanks over conventional (hollow) ones: to create a full-fledged treatment plant, conventional tanks will require large quantity. The most common are septic tanks with reinforced concrete structure, as they are considered durable and reliable.

What is a septic tank and how it works septic tank are two main issues that arise during the construction of a country house. After all, not a single arrangement of the sewer system in the country can do without it. The functional efficiency of the entire sewer system will depend on which type of septic tank you choose. Therefore, next we will talk about what is the working principle and imagine visual diagrams arrangement of sewerage different types designs.

purpose given element system consists in the temporary accumulation of wastewater and their subsequent treatment.

Septic - what is it?

A septic tank is a structure that is designed for the temporary accumulation of wastewater from residential buildings that cannot be connected to a centralized sewerage system, and their further treatment. By itself, it is not a complete treatment facility. A septic tank is necessary to collect a full-fledged autonomous local treatment plant.

According to the rules, after the effluents pass through this structure, they still need additional soil treatment.

Exist different designs septic tanks that differ principle of operation and device. Once in the septic tank, the effluents undergo mechanical and biological treatment using special bioenzymatic agents, which are described in the article The best means for septic tanks and cesspools: description, application. However, the cleaning process does not end there. Further, the effluents are subjected to forced and natural soil post-treatment. Some septic tanks are additionally equipped with biofilters or bioloading.

Components of a septic tank

All cleaning structures consist of:

Tank for settling drains. Such containers are most often made of plastic, metal. If a septic tank is equipped do it yourself, then such a tank is built underground from concrete or brick.

Advice! It is better to choose products made of fiberglass and polypropylene, as these materials are resistant to abrasion.

Pipeline: incoming and outgoing. Pipes for overflowing wastewater are installed at a slope so that the liquid flows smoothly between the tanks.
Service elements: wells and manholes. There must be at least 1 well on the outer route of the sewerage pipeline. If the length of the structure exceeds 25 meters, there should be 2 wells.
Ventilation system. It is necessary for air exchange, which ensures the maintenance of the desired temperature, the removal of methane and the normal vital activity of microorganisms. The most simple ventilation it is constructed from 2 risers: 1 is installed at the beginning of the sewer system, 2 - at the extreme section of the septic tank.

Important! If filtration fields are being equipped, a ventilation riser must be installed on all drainage pipes.

Types of septic tanks and their device

There are several types of septic tanks, which differ in the principle of operation:

Principle of operation

The principle of operation of the treatment plant consists of several stages. Let's consider it on the basis of a classic deep cleaning treatment plant of three chambers:

From the house to the sump (the first chamber of the treatment plant) there is a sewer pipe, through which drains flow.
Filter meshes are installed in the sump, thanks to which solid contaminants are separated from the liquid and fall to the bottom. The more impurities settle to the bottom, the higher the liquid rises. As soon as it reaches the level of the overflow pipe, which is located at 1/3 of the height of the tank, the effluents begin to flow into the second tank. This arrangement of the pipe eliminates the risk of returning wastewater to the sewer system.
In the second tank, wastewater is cleaned due to chemical neutralization. For this, special reagents are used that cause a fermentation reaction in which methane is released.
Methane is removed from the septic tank through the ventilation pipe.
Microorganisms remain in the treated wastewater. Small particles of waste are filtered and settle to the bottom.
Water flows into the third tank, purified from suspensions and impurities. It is necessary to neutralize the bacteria from the second chamber. This is done using ultraviolet radiation, fine filters or aerobic microorganisms.
After this treatment, the effluent enters the filtration fields and is discharged into the soil. However, activated sludge from the last tank must be periodically removed, otherwise the septic tank will not work effectively. The tank has a sensor. It will work when the sludge accumulates to a certain level.
The advantage of such septic tanks is that you can discharge drains with any composition. The septic tank can process toilet paper and inorganic matter in small quantities.

Important! Thanks to the multi-stage filtration of wastewater, effective treatment is carried out.

All structures are easy to install and maintain.

Watch the video! Septic tank made of concrete rings

Three-stage septic tanks with soil filtration

Three-stage septic tanks with soil filtration are installed in places with low groundwater. In some facilities, a soil filtration well is used instead of a third biological treatment tank. This method allows you to clean wastewater by 85-90%. It is based on the fact that in the upper layers of the soil there are bacteria that perform the functions of post-treatment of wastewater treated in a septic tank. With this filtering, you can:

get rid of non-drinkable water,
disinfect activated sludge, which becomes an ideal fertilizer.

Important! The thickness of the useful soil layer is 2 m, so for cleaning a large number drains use filtering fields. This allows for the mineralization of wastewater occurs in a layer of soil 50 cm thick.

The interval between draining effluents into the ground for filtration should be at least 5 days. This method is environmentally friendly. However, harmful compounds and chemically active substances should not be present in the drains, so as not to kill beneficial bacteria.

Important! For the vital activity of soil bacteria, oxygen is needed, so you should make sure that it enters the place of filtration. In this case, the degree of purification will reach 99%.

At the bottom of the filtration well, drainage is made from a layer of gravel, crushed stone or expanded clay. Irrigation pipes are laid above the filter, leaving at least 1 m to groundwater.

Septic tank with biological treatment

Bioseptic - a design with deep cleaning with the help of microorganisms. A septic tank with biological treatment consists of a sealed block, reinforced with stiffeners, which is divided into several tanks. Effluent flows into the septic tank through the sewer pipe and into the septic tank, where it undergoes various treatment methods. At the outlet, the water is 90-98% purified, so it can be used for irrigation or drained into a reservoir. It does not require additional filtration.

Bioseptics are suitable for installation in any geological conditions with any occurrence of groundwater. A septic tank must be installed and connected to the sewer. No other additional components need to be installed.

Principle of operation:

In the first tank, the effluent is settled. Heavy sewage settles to the bottom, and the liquid remains on top. They are processed by anaerobes (bacteria), oxygen is not needed here.
In the second chamber, organic and inorganic substances decomposed by aerobic microorganisms. They need oxygen for processing and their own life.
In the third compartment, pre-cleaned effluents are disinfected chemical elements or aerobic bacteria.

Oxygen is supplied to the chambers using an aerator, so most bioseptics are powered by electricity.

Watch the video! Country Bioseptic Compact