Single-chamber septic tank of large volume or multi-chamber. How to choose a septic tank: tips on which one is better to choose a septic tank for a private house

Just like the townspeople, they want to have a comfortable home. And to do this without the proper arrangement of the sewerage system is almost unthinkable. Such communications include not only plumbing units and pipes, but also a structure for the disposal of wastewater. Previously, this role was performed by a simple cesspool, from which it was necessary to constantly pump out the accumulated sewage. But today you can use modern tools and technologies that allow you not to use the services of sewers. This article will talk about what a three-chamber septic tank is, how a septic tank functions and how you can do it yourself.

Basic principles

Cesspools, which were used earlier, are gradually becoming a thing of the past today. Modern technologies make it possible to improve the efficiency of such devices, and to make sure that drains do not harm the environment. At the same time, there would be no need to pump out the accumulated sewage.

The main feature of the operation of such a device is to clean the drains and dispose of them in the ground. For this, a whole complex is being created, which will consist of:

• several containers (usually two or three);
• pipes for connecting the sewerage system with a septic tank and for connecting containers to each other;
• ventilation shafts for each tank;
• sealed lids for containers.

All drains from the sewerage system enter the first tank, which is completely sealed. In it, sewage is settled and further processed by colonies of microorganisms. The latter are brought into the container artificially (special biological products), through the sewerage system.

After filling the first container to a certain level, the water flows through the pipes into the second. If the system consists of three tanks, then the second one will also be sealed. Here, undecomposed waste will settle to the bottom, and purified water will flow into the third container.

The last tank is made leaky. Through it, passing through a pillow of gravel and sand, treated effluents fall into the ground.

Since modern biological products (or rather, the colonies of microorganisms present in them) are able to process almost all organic residues, such a septic tank can work without pumping from 50 to 100 years. The main thing is that inorganic pollutants and substances harmful to bacteria do not get into the drains.

Stages of work

Now let's talk about how to make a three-chamber septic tank. First of all, it is necessary to choose the right material for construction. There are several options:

• pouring reinforced concrete;
• use of ready-made concrete rings;
• application of brickwork.

All these materials are able to withstand the detrimental effects of both sewage runoff and the aggressive soil environment. In addition, concrete and brick can last more than 50 years. And that's exactly what this system should work for.

The difference in the material will be only in your capabilities and the required volume of the treatment plant. The installation of reinforced concrete rings does not require special skills of the builder, but the use of such structures can limit the volume of the tank. The pouring of reinforced concrete and the use of brickwork, on the contrary, does not limit the size of the resulting containers. But it requires some building skills.

If you figured out the choice of material, then you should think about the location of the septic tank. It is important to comply with sanitary and building regulations. Tanks should not be close to a water source (from 10 to 30 meters minimum) and from residential buildings (from 10 to 15 meters).

It is also not worth placing a septic tank too far from the sewer outlet. This will incur extra costs. Also, a long sewer route is an additional operational problem and the possibility of blockages and freezing of sewer pipes in the winter.

After determining a suitable place, we proceed directly to the construction. It is carried out in several stages:

1. The first stage is earthworks. At the selected location, one or more pits of the desired size are dug.
2. The second stage - we bring the sewer pipes. For this, a trench is dug from the house to the location of the first container up to half a meter deep. At the bottom, a pillow is made of sand and gravel. Do not forget about the need for a slope towards the septic tank and about the insulation of pipes.
3. The third stage is building containers. First, a pillow of crushed stone and sand is made at the bottom. Then the bottom under the first container must be concreted to make it airtight. After that, walls are erected (from brickwork or by pouring concrete). In this case, it is necessary to install connecting pipes, through which drains will flow from one container to another. During the construction of the last tank, the bottom remains leaky. It is also possible to mount several pipes coming out of the bottom of the tank, with drilled holes. They are laid on a pillow of crushed stone or gravel and covered with the same composition. Through these pipes, purified water will also seep into the ground.
4. The fourth stage is the installation of hatches and ventilation shafts. When using ready-made concrete rings, problems with the hatch should not arise (you can purchase ready-made products). If the containers are made of brickwork or concrete, then they can be covered with iron sheets on top or a concrete screed can be made. Inspection hatches and ventilation shafts can be mounted in such a "roof". You can learn more about such works by watching the video.

After all these works, you can fill up the pit and ennoble the territory. As soon as the drains begin to fill the first container, you can add a biological product with a colony of microorganisms to it. In a few days they will begin to multiply and process sewage.

In order for the septic tank to effectively perform its functions, it is worth following some rules. Firstly, sewage should not be allowed to flow for a long time. If this happens, then the colony of microorganisms may die. Secondly, it is impossible to drain some substances harmful to bacteria into the sewer. The instructions for biological products contain a list of all prohibited drugs. Also, do not allow inorganic substances to enter the drains, they can quickly fill the containers. If all this is observed, then you can use such a septic tank for more than 50 years. In this case, the services of sewers will not be required.

Video

Today, even in the private sector, people simply do not want to live without comfortable conditions. Washing machine, dishwasher, plumbing - how can you do without sewage? And if the family is large, then the accumulation of wastewater occurs rapidly and in this case a simple pit cannot be dispensed with.

Yes, and why "multiply" bacteria in your area, if today a universal engineering structure has been invented, where wastewater is "hidden", and sometimes undergoes additional treatment and at the exit, even "watered" the garden.

Which septic tank to choose

The demand for such a structure was the impetus for the appearance of a septic tank in various versions, with a well-thought-out complex building structure, using a multi-stage cleaning system. Over time, the structure evolved from a simple cesspool, first into a single-chamber septic tank made of concrete rings, and then into a complex treatment plant.

Engineering thought does not stand still and today the single-chamber system has been replaced by a complex multi-chamber system with filters, the latest methods of wastewater treatment.

Choosing a system is not easy, because not only the budget, sometimes limited, plays a role, but the dimensions of the structure must also be acceptable, and the appropriate place for the septic tank must be found.

For example, if the flow of water per day is 5 cubic meters, then the tank will have to accept at least 3 cubic meters of water. An average family of 5-6 people can produce up to 2 m3 of wastewater per day, especially if the living conditions are comfortable: washing machine, toilet bowl, shower, etc.

And here you also want the sewerage system to work smoothly and for a long time. Therefore, the competent construction of a sewer well is not complete without determining the number of chambers in the structure; the quality of the water used depends on their number.

Even regulatory documents are trying to regulate the intake of wastewater, for a specific type of system (photo):

• Single chamber version - up to 1 m³
• Two-chamber - up to 10 m³
• Three-chamber - more than 10 m³

The first chamber in any variant of the well should be the largest. Only in a septic tank made of concrete rings everything is different, the chambers are all the same size. Additional chambers are needed in order for the water runoff to pass through all periods of decomposition in 2-3 days.

How a multi-camera system works

Engineering design consists of:

• Capacity for sedimentation of drains.
• pollution.

• Tank or well for infiltration.

The presence of additional chambers will depend on the level of discharge of the amount of water, the larger the volume of waste, the more difficult it is to recycle.

The more people live in the house, the more water flow will be.

The principle of operation of a multi-chamber system

The main advantage of the multi-chamber option can be explained by the waste treatment principle:

1. Sewage wastes fall from the sewer pipe into the first chamber.
2. Liquid is filtered in it, heavy waste precipitates to the bottom. Dirty water "settles".
3. As soon as the liquid is recruited to a certain level, overflow occurs.
4. The liquid cleared of large waste is poured into the second chamber, the process is repeated.
5. In the third chamber, we have almost pure water, which is similar in composition to the so-called "technical water".

You can use such a drain to irrigate the site, if there is nothing to water, then just let your purified water go into the ground.

What are the requirements for a septic tank?

• Ventilation. Bacteria, processing waste, form gas.
• Smart choice of cameras. The three-chamber option is considered the most successful, especially if your plans do not include regular pumping of the septic tank.
• Construction volume. It is considered ideal if it can accept a three-day family flow rate.
• thermal insulation. It's good to have hot water in your home, but don't forget that bacteria ideally thrive in a warm environment.
• Waterproofing. It is necessary to equip any septic tank hermetically, so you will protect your structure from freezing, from melt water and precipitation.

Advice!
You can install any septic tank yourself.
This is a simple structure, especially since the construction process can be slightly accelerated by hiring, for example, special equipment for digging a pit, or for installing rings.

Construction of a multi-chamber structure

You will surely find the step-by-step instructions useful.

In order to competently approach the construction of any septic tank, it is better to adhere to a certain plan:

1. Carry out all the calculations, sketch out an approximate plan-scheme.

1. Sealing rings, all joints.

1. Fill the entire structure with soil, lay the covers.

Proper construction of a septic tank implies a competent sequential arrangement of rings. This is especially important when building a two-chamber septic tank with your own hands.

Advice!
All rings are installed according to a certain scheme, tightly connecting with each other.
Chambers with concrete rings are connected by pipes.
A do-it-yourself single-chamber septic tank does not contain an additional chamber.
But it can be connected to a drain or drainage.

Installation of several cameras, especially when a two-chamber septic tank of concrete rings is planned, can be done in stages:

1. In the prepared pit, we install rings for the first chamber using special equipment.
2. We do the same work with the second and, if planned, the third camera.
3. We install overflows by punching holes in the rings.
4. We close up the joints.
5. We start the inlet pipe into the first chamber into the last pipe to the outlet.
6. We cover all the chambers with hatches, and fill the structure with soil.

Conclusion

If you plan to use the septic tank for a long time, then the structure must be built in accordance with all the rules, which means that you cannot do without high costs in this matter. The construction of a septic tank is an expensive occupation, especially a multi-chamber one.

The cost of construction will consist of hiring equipment (this is already 7-8 thousand), a work team, and the cost of rings.

Only the correct placement of the sewer system, competent installation will relieve you of the smell of sewage, and make your family's stay in the house comfortable. The video in this article will help you get more information.

Let's start with the theory.

septic tank- (from the Greek septikos - putrid) - a facility for treating small amounts (up to 25 m3 / day) of domestic wastewater. It is a horizontal type underground sump, consisting of 1 or more chambers through which waste liquid flows (Big Encyclopedic Dictionary).

Earlier, I already wrote that it is not used independently, but only in combination with post-treatment, which is carried out in the soil. SNiP 2.04.03-85 "Sewerage. External networks and structures" places emphasis in a slightly different way:

"6.78. Septic tanks should be used for mechanical treatment of wastewater entering underground filtration fields, sand and gravel filters, filter trenches and filter wells."

Based on the logic of SNiP, the main treatment facility in this pair is precisely the soil filtration facilities, and the septic tank is used only for preliminary mechanical cleaning. And this is very correct, if we talk about cleaning the "water" component of the drain. That's right - the septic tank carries out preliminary treatment of wastewater from mechanical impurities (sludge). I will add - and it ferments the sediment, mineralizes it to a state suitable for agricultural use as a fertilizer.

Now you understand that all the talk that the septic tank provides insufficient cleaning, to put it mildly, is speculative. It also should not give "sufficient". The main purification takes place in the soil. This is how it is formulated in the territorial building codes TSN EK - 97 MO "Technical rules and norms for the construction, operation and control of the operation of structures for drainage systems of low-rise buildings"​​:

"​Septic tanks are designed for pre-treatment of wastewater and rotting of the precipitated sludge and are used in individual and local drainage systems."

Let's see what quality the effluent enters the septic tank, and what quality it must leave it for everything to work fine. Let's take one single, but very important indicator for preliminary cleaning - suspended solids.

Let's turn to the regulations. "Methodological recommendations for calculating the quantity and quality of wastewater and pollutants received into the sewerage systems of settlements", approved by the order of the Gosstroy of Russia dated April 6, 2001 N 75, give us averaged characteristics of the quality of domestic wastewater discharged by subscribers of the housing stock of settlements. For suspended solids, this characteristic is 110 mg/l. At the same time, according to TSN EK - 97:

"Reliable operation of soil treatment systems is possible if preliminary treatment facilities ensure the proper quality of treated water. The concentration of suspended solids in wastewater after septic tanks should not exceed 100 mg / l. When filtering facilities operate in the post-treatment mode - 20 - 30 mg / l."

As you can see, a lot is not required from a septic tank. If it removes 40-60 percent of suspended solids, then at the exit from it we will get from 40 to 70 mg/l of suspended solids. That is, it is already closer to the post-treatment mode, rather than cleaning. The actual treatment of the runoff will take place in the soil.

How big should a septic tank be? This question is exhaustively answered by SNiP 2.04.03-85 "Sewerage. External networks and structures":

"The full estimated volume of the septic tank should be taken: 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.
Depending on the flow of wastewater, one should take: single-chamber septic tanks - with a wastewater flow rate of up to 1 m3 / day, two-chamber - up to 10 and three-chamber - over 10 m3 / day.
The volume of the first chamber should be taken: in two-chamber septic tanks - 0.75, in three-chamber - 0.5 of the calculated volume. In this case, the volume of the second and third chambers should be taken at 0.25 of the calculated volume.
"In septic tanks made of concrete rings, all chambers should be taken of equal volume."

As you can see, it is not so important what size of the chamber, more important considerations are the convenience of construction. Well, why do we still need these several cameras? Water does not care how many chambers it flows through, the residence time is important, and it is determined by the total volume of the septic tank. What is one section, what is three - everything is one. If only the total volume was appropriate.

But the sediment is not all the same. If there is only one section, the sediment will not fall out evenly in it. At the beginning of the septic tank, it will fall out more than at the end. That's why they make several sections. To concentrate the bulk of the sediment in the first section and avoid re-contamination of the water with sediment decomposition products. Yes, and cleaning one small section is more convenient than the entire septic tank. Some technical publications even recommend different cleaning intervals for septic tank sections.

Well, why is it necessary to deal with secondary pollution of the drain? After all, cleaning is still going on in the soil and the load on it is permissible.

The thing is that this secondary pollution is important when released from the septic tank directly into the reservoir. Then, avoiding secondary pollution, we will get cleaner water at the outlet.

But according to Russian laws, after a septic tank, it is impossible to dump water into a reservoir and onto a relief! Therefore, the degree of secondary pollution should not interest us as much as, say, the Europeans. Compare - according to EU standards, BOD (biochemical oxygen demand - an indicator that describes the amount of organic matter in wastewater through the need for oxygen for its oxidation) in wastewater discharged into a reservoir can be 25.0 mg / l. And according to Russian standards - 2.0 mg / l. An order of magnitude difference!

So they use the sectioning of the septic tank to eliminate secondary pollution and additional chambers (increasing the total volume of the septic tank) in order to "reach" the quality of cleaning up to the coveted 25 mg / l.

Complete fermentation (cleaning) of the mixture of waste water and sludge takes one to two months. In practice, they are limited to shorter periods, in which, of course, only partial decomposition occurs. The minimum residence time for wastewater in a septic tank is two days. In this case, only partial decomposition of sewage impurities occurs, so that small-volume septic tanks mainly serve to remove suspended solids. To obtain a higher degree of purification, keeping the contents for 10 days is required. In this case, the wastewater can be considered purified, since due to the presence of putrefactive bacteria, biological decomposition has partially occurred in it. Septic tanks designed for a two-day holding of wastewater have, as a rule, a small volume, in contrast to multi-chamber decomposers designed for a 10-day stay of water. Wastewater from septic tanks designed for a short residence time should not be discharged directly into the reservoir, as it has not been sufficiently treated.

Do you understand, dear reader? A septic tank designed for 10 days will give 25 mg / l of BOD and effluent from it can be discharged into a reservoir. But only in Europe. And to achieve our two m / y this is not enough. Therefore, we do not use such large septic tanks. Therefore, sectioning a "three-day" septic tank will do little, except for the relative convenience of removing sediment from it.

And you already know how to respond to talk that this improves cleaning. What's the point of hand-picking the crumbs off the carpet if you vacuum everything afterward? After the septic tank, you will still have soil treatment, which will clean the drain to the standard.

Now about the additional sections of the septic tank (or about increasing its volume against the standard three-day one). Since additional sections of a septic tank provide additional quality of cleaning, they can be used to extend the life of underground filtration facilities. It is obvious that the cleaner the drain is fed to them, the more sparingly they will work. And the longer. You ask, why take longer, you can clean it?

The fact is that the filter well is really relatively easy to clean when it is silted up. But underground filtration fields and filter trenches used at high flow rates will have to be made new, it is impossible to clean them, you can only deal with their siltation by washing with chlorine water, however, not effectively enough.

What is the period of operation of filtering facilities before the need arises for their cleaning and (or) replacement? TSN EK - 97 MO gives the following figures:

"During normal operation in the post-cleaning mode of filter trenches and sand and gravel filters, their service life until the complete replacement of the filter load and drains is 15-18 years, filter wells and underground filtration fields - 8-10 years."

Here is the clue to the appearance of additional cameras in septic tanks. If you want to extend the life of soil filtration facilities, build additional sections.

I will make a special reservation - do not section the "three-day" septic tank, but increase its volume with additional sections. However, I consider 8-10 years to be quite an acceptable period, and I do not advise building additional sections. But this, as they say, is a matter of taste and desire of a particular user.

Now that we have finally figured out what kind of septic tank is needed, it's time to start talking about how to make it. In fact, there are only two ways - buy and install ready-made and make it yourself. They will work the same if you buy or build a normal structure, but the cost will differ by an order of magnitude.

Andrey Ratnikov. Technical Director of LLC SPO "BioStroy"

Living in your own home will be comfortable if the owners provide for this all the necessary conditions. Few people are already attracted to options with the delivery of buckets of water from a well, with a board toilet on the site. All this is acceptable for dacha conditions with periodic arrivals on weekends, but it looks like a complete anachronism if the family lives in the house permanently. And this means that normal housing should be equipped with water supply and sewerage. Well, if in the village there is the possibility of connecting to the central highways and collectors. But such cases are quite rare, and more often it is necessary to create completely autonomous systems.

How to choose a septic tank - detailed instructions

Water supply is a separate multifaceted topic, and in this case we are interested in the creation of an independent sewerage system. Discharge of untreated wastewater into the environment is strictly prohibited. This means that it is necessary to install special structures or devices for collecting, settling, cleaning, clarifying wastewater. In the practice of private housing construction, the best solution to this issue is the use of special containers - septic tanks. Such an element can be built on its own or purchased ready-made. This publication will discuss how to choose a factory-made septic tank, that is, what criteria for evaluating a product should pay special attention to.

What is a septic tank. The principle of its action

A septic tank is the most important element of an autonomous sewage system or treatment plant. And, although it is not a complete wastewater treatment scheme in itself, its role is extremely important.

The main purpose of any septic tank is the collection of all sewage from a house (a group of houses), their settling and preliminary biological treatment of varying degrees of depth. The effluents that have passed such a cycle are discharged into ground filtration devices or structures, or are subject to regular pumping using special equipment. In any case, it excludes the ingress of polluted effluents into the environment, representing a chemical and bacteriological hazard to it.

There are many options for how to provide drainage and treatment of wastewater on a private site. The device of the septic tank Tank, Topas, Astra and others is a design that can simultaneously perform these functions.

The easiest and cheapest option. The device of a septic tank made of concrete rings is very similar to a classic cesspool, but with additional wall sealing. It consists of concrete molds, which can have different diameters and widths, bottoms, covers and pipes that supply water. In most cases, this design does not involve the further use of waste liquid - when overflowing, water is simply pumped out of the tank. But sometimes the owners equip such a well with a drainage pump that pumps out the technical fluid.

When water enters the well, through the influence of gravitational forces, solid particles from the drains immediately settle to the bottom. Within a few days, fermentation occurs, due to which some more litter falls into the sediment. Further, if it is equipped with a pump, the water passes through the filters with the help of a compressor and is discharged into another storage tank. From it, it can be used to irrigate the field, fertilize plants, etc.

Related video:

The arrangement of such a storage single-chamber septic tank is not difficult:

1. A hole is dug, which is compacted with rubble and sand, the bottom is installed;
2. Concrete rings and other seals are installed in it. They pre-provision a hole for the inlet and outlet of the sewer pipe;
3. After that, the cover is mounted.

The design of a septic tank made of reinforced concrete rings has both advantages and disadvantages. Pros: simplicity and affordability, cesspool rings can be easily made with your own hands. Cons: for such a well, regular cleaning is mandatory. This option is convenient for a toilet or shower in a country house where there is not a large amount of drains, but it is recommended to use autonomous treatment stations to equip a private building. By the way, a septic tank made of plastic containers, in particular, barrels or eurocubes, has similar properties.

Topas (Topaz)

Topas (Topaz) is a septic tank, the device of which is an example of a classic biological purifier. It works due to the presence of anaerobic bacteria in the filters. These microorganisms are able to stay without air for a long time, from which their vital activity does not suffer. The septic tank consists of several chambers, each has a specific purpose:

1. Primary cleaning compartment. This is where sewerage comes from. In this department, water is purified from solid waste;
2. Aerotank. The most important part of the system is the bacterial tank. It is here that special anaerobic filters are located, which clean the effluents from liquid contaminants, chemical compounds and grease. There are two filters here: one at the inlet to the tank, the other at its outlet;
3. Sump. With the help of an overflow hose and a pump, water from the aeration tank enters the settling chamber. The technology of biological septic tanks involves the treatment of wastewater for several days; it spends at least 3 (sometimes 10) in the sump. Here the remaining solid particles settle to the bottom, and the purified liquid flows further;
4. Cleaning chamber. The last section that separates the septic tank from the sewer. With the help of a filtering surface, water is purified from traces of bacteria, grease residues, etc.

This septic tank can be used for a bath, toilet, shower, private house and even several buildings. To protect the case from earth pressure, you will need to use a home-made or purchased metal frame.

Tank

A tank is a septic tank in a private house, the device of which implies the presence of several treatment chambers and sedimentation tanks. It is a complete self-contained treatment system that simultaneously settles and cleans the drain. There are models of aerobic and anaerobic principles of work. Accordingly, the action of this antiseptic is produced both with the help of oxygen-sensitive bacteria and with the use of insensitive microorganisms.

The device of an autonomous two-chamber septic tank Tank:

1. Large capacity, which is divided into two separate tanks: additional treatment, biological aeration tank. The first runoff comes from the sewer and settles for several days for further treatment. In the aerotank, water passes through several filters, after which it is led through the pipe to the infiltrator;
2. The installation of this type of septic tank involves the installation of an infiltrator - a separate part of the structure in which wastewater is cleaned by means of soil or other absorbent substances. From here, part of the effluent enters the ground, the rest (if necessary) is carried further for technical use.

This is ideal for a large city cottage or private home. It should be noted that after the Tank, the wastewater meets the requirements of the technical water standard: it is 90% purified. Its analogue is Unilos Astra, but it is designed for other amounts of work. Also, their design complies with SNiP 2.04.04-84.

Tver

The scheme of the three-chamber septic tank Tver is volatile, its principle of operation involves the use of electrical energy for cleaning wastewater. That is why it is rarely used for drainage in the country or in a country house. It consists of a large PVC container with three compartments. Each performs a certain cleaning of drains. One of the main advantages of this model is that after it the water does not need to be cleaned with an infiltrator.

The device of the septic tank Tver:

1. The pipe from the sewer is brought to the inlet pipe of the installation. In the tank, gravitational cleaning and running of water through large filters takes place;
2. In the next compartment, biological cleaning is carried out. Anaerobic bacteria “work” here;
3. The last tank is characterized as an aftertreatment tank. Water is distilled several times through special filters - this helps to get rid of odor and grease residues.

Among the advantages is that a drainage and drainage system can also be connected to the septic tank, but it also has certain disadvantages. In particular, with a high level of groundwater, it will be quite difficult to install a septic tank of such a device with your own hands. In viscous soil (clay, loam), flooding of the system may occur. To avoid this, you will need to additionally equip the pits with an iron mesh or make a body of concrete, stone, brick.

Price overview

The cost for the purchase of septic tanks, maintenance of systems, their installation and cleaning may vary depending on the city of residence and the brand of the facility.

The estimate may also include additional costs for site preparation and sewer connection.