How to calculate the volume of a septic tank. How to calculate the volume of a septic tank for a house or cottage. Example calculation for a family of four

To connect plumbing fixtures to the water supply network, a flexible water supply is used. It is in demand when connecting faucets, showers, toilets and other water intake points, and significantly simplifies the installation process. Flexible connections are also used when installing gas equipment. It differs from similar water devices in its manufacturing technology and special safety requirements.

Characteristics and types

The flexible hose for connecting plumbing is a hose of different lengths made of non-toxic synthetic rubber. Thanks to the elasticity and softness of the material, it easily takes the desired position and allows installation in hard to reach places. To protect the flexible hose, there is an upper reinforcing layer in the form of a braid, which is made from the following materials:

• Aluminum. Such models can withstand no more than +80 °C and retain functionality for 3 years. At high humidity Aluminum braiding is prone to rust.
• Stainless steel. Thanks to this reinforcing layer, the service life of the flexible water line is at least 10 years, and the maximum temperature of the transported medium is +95 °C.
• Nylon. This braid is used for the manufacture of reinforced models that can withstand temperatures up to +110 °C and are designed for intensive use for 15 years.

The fasteners used are nut-nut and nut-fitting pairs, which are made of brass or stainless steel. Devices with different permissible temperatures differ in the color of the braid. Blue ones are used for connecting to a pipeline with cold water, and red ones - with hot ones.

When choosing a water line, you need to pay attention to its elasticity, reliability of fasteners and purpose. It is also mandatory to have a certificate that prevents the rubber from releasing toxic components during operation.

Features of gas connections

When connected gas stoves, speakers and other types of equipment also use flexible hoses. Unlike water models, they are yellow and are not tested for environmental safety. For fixation, end steel or aluminum reinforcement is used. There are the following types of devices for connecting gas appliances:

• PVC hoses reinforced with polyester thread;
• made of synthetic rubber with stainless steel braid;
• bellows, made in the form of a corrugated stainless steel tube.

Santekhkomplekt holding offers engineering equipment, fittings, plumbing and devices for connecting it to communications. The range is represented by products and materials from well-known foreign and domestic manufacturers. Discounts apply for bulk purchases, and product quality is confirmed by standard certificates. For information support and assistance, each client is assigned a personal manager. The ability to arrange delivery within Moscow and to other regions of the Russian Federation allows you to quickly receive the purchased goods without unnecessary hassle.

Drainage is a drainage and drainage measure to remove excess groundwater.

If water does not leave the site for a long time, the soil becomes gleyed, if shrubs and trees quickly disappear (get wet), you need to urgently take action and drain the site.

Causes of soil waterlogging

There are several reasons for soil waterlogging:

• clay heavy soil structure with poor water permeability;
• aquifer in the form of gray-green and red-brown clays is located close to the surface;
• high groundwater table;
• technogenic factors (construction of roads, pipelines, various objects) that interfere with natural drainage;
• disruption of the water balance by the construction of irrigation systems;
• The landscape area is located in a lowland, ravine, or hollow. In this case, precipitation and the influx of water from higher places play a big role.

What are the consequences of excess moisture in the soil?

You can see the results of this phenomenon yourself - trees and shrubs die. Why is this happening?

• the oxygen content in the soil decreases and the carbon dioxide content increases, which leads to disruption of air exchange processes, water regime and nutritional regime in the soil;
• oxygen starvation of the root-forming layer occurs, which leads to the death of plant roots;
• the supply of macro and microelements by plants (nitrogen, phosphorus, potassium, etc.) is disrupted, because excess water washes out mobile forms of elements from the soil, and they become unavailable for absorption;
• intensive breakdown of proteins occurs and, accordingly, the processes of decay are activated.

Plants can tell you at what level groundwater lies

Take a close look at the flora of your area. The species inhabiting it will tell you at what depth the ground water layers are located:

• perched water - it is best to dig a reservoir in this place;
• at a depth of up to 0.5 m - marigold, horsetails, varieties of sedges grow - bladderwrack, holly, foxtail, Langsdorff's reed;
• at a depth of 0.5 m to 1 m - meadowsweet, canary grass, ;
• from 1 m to 1.5 m – favorable conditions for meadow fescue, bluegrass, mouse pea, china;
• from 1.5 m - wheatgrass, clover, wormwood, plantain.

What is important to know when planning site drainage

Each group of plants has its own moisture needs:

• at a groundwater depth of 0.5 to 1 m they can grow on raised beds vegetables and annual flowers;
• water depth up to 1.5 m is well tolerated vegetable crops, cereals, annuals and perennials (flowers), ornamental and fruit and berry bushes, trees on a dwarf rootstock;
• if the groundwater is more than 2 m deep, fruit trees can be grown;
• optimal depth of groundwater for agriculture– from 3.5 m.

Is site drainage necessary?

Write down your observations for at least some time. You yourself can understand how much drainage is needed.

Maybe it makes sense to simply redirect melt and sediment water along the bypass channel, rather than allowing it to flow through your site?

Perhaps it is necessary to design and equip a storm drain and improve the composition of the soil and this will be enough?

Or is it worth making a drainage system only for fruit and ornamental trees?

A specialist will give you the exact answer, and we strongly recommend calling him. But after reading this article, you will gain some awareness on this issue.

Upon completion of technological and production tasks related to the arrangement of the sewer system in apartment building, industrial building, as well as in private households, it is required to test the involved system using the forced flow method. This task is used to identify possible defects or improper installation of the entire involved sewerage part and the test report for internal sewerage and drainage systems will be material evidence of the work on acceptance of the facility.

A visual inspection should be accompanied by inclusion in the test report of internal sewerage and drainage systems according to SNIP, which is currently represented by the current regulations of the “D” series appendix, which corresponds to SP 73.13330.2012 “Internal sanitary systems of a building”, recently a new one has been applied updated working edition according to SNiP 3.05.01-85.

Installing an autonomous sewer system on your site is not at all easy, but it is necessary in the absence of a centralized city system to ensure comfortable living.

An important component of the entire system is the septic tank, whose task is to receive and purify sewage and release purified liquid. At the same time, it is important to know exactly how to calculate the volume of a septic tank for a home, so that in the future there will be no problems with the septic tank overflowing.

What does the calculation consist of?

Correct calculation of all parameters is necessary not only to obtain the exact volume of the future structure, but also to calculate building materials if it is built with your own hands.

Internal chambers of a septic tank for a private house

Therefore, the following details are calculated:

• dimensions of factory containers;
• daily volumes of wastewater that the device is capable of receiving and processing;
• volumes of water used by people living in the house;
• building materials for the installation and construction of a septic tank.

Installation of both a factory-made and a home-made septic tank is carried out only after all parameters and possibilities have been calculated.

Naturally, the material resources that are planned to be spent on its arrangement are also taken into account.

Very often, for those who only occasionally, on weekends, are at the dacha, the installation is sufficient homemade device made of bricks, tires or concrete rings.

If you live in a house all year round, it is best to purchase a factory version.

What else needs to be considered

Before digging a pit, you need to know the exact dimensions of not just the structure itself, but also all the pipes, compressors and necks that occupy individual places.

taking into account the structure of the septic tank and the volume of each of its chambers

The installation of a septic tank must be carried out strictly in accordance with SNiP number 2.04.03-85, which indicates the exact distances of the proposed device from other objects. So:

• the distance to the house must be at least five meters;
• to drinking well on loamy and clayey soils - from twenty-five to thirty meters, and on sandy and soil soils - from forty-five to fifty;
• to garden trees- from five meters;
• to the neighboring plot - from two meters;
• to the access road - from three to four meters;
• to a public road - from five to ten meters.

All these standards are taken into account at the design stage. To help, engineers and designers draw up calculation tables that are easier to navigate if the site has few square meters, but the device is still required.

In addition, the depth of the structure is also calculated. It must be more than 130 centimeters, and the width and length - more than one meter. The specified parameters are most suitable for accommodation of one or two people.

Depth has its maximum. It is advisable not to make the depth of the septic tank more than three meters if it is planned to carry out cleaning with a sewer machine.

Volume formula and number of people

For an accurate calculation there is a standard formula:

W=K*Q, where K means the settling period of wastewater, and Q is the flow rate per day.

For more simple option They use the daily norm of one person - two hundred liters, multiply the number by three (this is the number of days spent on wastewater treatment) and divide the resulting amount by a thousand.

However, this is only a preliminary result. Values ​​may change depending on the people who are added as residents - temporarily or permanently.

storage type septic tank size

The volume of the future structure directly depends on the number of people living in the house. There are special tables for this, which can also be used in calculations.

Manufacturers of sewer septic tanks proceed from the useful volume parameter, which has an average value per day - two hundred liters. Based on this indicator, all that remains is to multiply the average number by the number of people living in the house, and you will get the number by which to choose a septic tank.

Materials for self-construction

To build your own septic tank, you also need accurate calculations based on which building materials are selected.

These include not only containers, but also materials for the manufacture and arrangement of a foundation for it, various solutions or sprinkling, and so on.

To calculate cement consumption, for example, SNiP number 82-02-95 is used.

For a concrete septic tank, rings are usually used, most often three. They have a standard diameter of one and a half meters and a height of ninety centimeters.

The resulting volume consists of a working volume and a so-called “dead” volume, located above the level of the outlet pipe, from where the purified water goes into the ground or onto filtration fields.

In addition to the rings, a cover plate and a cast iron hatch are used. Also important are the materials for the construction of the ventilation system, the main part of which is an asbestos-cement pipe, at least one and a half meters long.

To obtain mixtures, there are also tables that provide exact ratios.

All materials for the construction are approximately the following:

• 3 concrete rings for one container;
• concrete ring with bottom;
• a concrete ring with holes (for filtration wells);
• plate;
• pipe for ventilation;
• cast iron hatch;
• cement, crushed stone, sand.

The tools you will need for installation include:

• crane;
• four to six installers;
• concrete mixers;
• buckets;
• a car with a metal body;
• shovel;
• cutting tools.

The sewer pipes are connected to the septic tank and tightly sealed.

If the septic tank serves, in addition to the sewage system inside the house, other drains, then appropriate consumables for them must also be provided.

choosing the size of the septic tank and its design

The cheapest homemade option will be a septic tank made from tires. However, even here it is necessary to adhere to clear calculations when arranging.

The foundation and backfilling occurs in the same way for all types of devices.

For a container made of bricks, calculate their approximate quantity, as well as bulk materials and other parts.

If it is planned to build a two-chamber structure, then the slab is made from a cushion of crushed stone.

To count bricks, there is a special table that tells you how much to use in square meters. In the resulting number, you need to include approximately 5% for brick breakage. Next, the masonry solution is calculated. It is best to use ready-made masonry mixtures, which can be found on the market in large quantities different types.

Example for a family of four

To find out how to calculate the volume of a septic tank, you first need to obtain a three-day approximate water consumption of a family member. Then calculate the time required to process the wastewater: 0.8xtx(100%-30%/100%)*120%=0.8xtx0.7x1.2=tx0.672 sec.

In this formula:

• 0.8 means the consumption of the remainder of large substances obtained from humans;
• t is the time of its decay per day;
• 100% - sludge volume;
• 30% - silt decomposition;
• 120%/100% - sludge volume and twenty percent of residues after cleaning carried out in the previous period.

Can be taken per person minimum consumption- one hundred and fifty liters per day.

Then the average consumption will look like this:

• per minute the soul uses about ten liters of water;
• shower lasts from seven to fifteen minutes;
• toilet usage is approximately eight liters;
• for a bath or jacuzzi one hundred and ten liters are consumed;
• the washing machine consumes approximately seventy liters;
• the dishwasher consumes fifteen liters.

Thus, for one person it turns out: 110+8*5+10*7+150=370 liters per day. This is the highest consumption per day.

Both the minimum and maximum numbers are specified in the relevant SNiP. To calculate the total consumption (Q) of water, including the dishwasher and washing machine, you get:

• Q=15+70+370*4=1.6 cubic meters.
• Remembering the formula Q*3, for the whole family we get 1.6*3=4.8 cubic meters.
• This number is considered the best estimate.
• The minimum indicator is calculated as follows: 4.8 * (1-0.2) = 3.84 cubic meters.

The rate cannot be reduced by more than twenty percent, as in the indicated formula. If this rule is ignored, the consequence may be flooding of the structure, which will lead to soil contamination.

Overflow septic tank with drainage system and aeration system

An example of calculating the depth of a septic tank:

• 4.8/1/1.8 - 2.6 m;
• 4.8 is cubic meters by volume;
• 1 - m width;
• 1.8 m length.

This calculation is used for small plot sizes.

In some regions, the depth of soil freezing is up to two meters or more. It is necessary to strictly adhere to the norms and rules of SNiP, since otherwise operation may be terminated and penalties may be imposed.

That is why, before installing a treatment plant, it is necessary to study all the rules and regulations on how to calculate a septic tank and strictly adhere to them.

Dachas and country houses have long ceased to be housing with amenities “in the yard.” New technologies and materials allow short term build a full-fledged sewerage system that will ensure the removal of wastewater from the kitchen, toilet, bathroom or bathhouse. Most often, it is not possible to connect the drainage line to a centralized network, so the problem of removing sewage from the site has to be solved independently, using the services of a sewage truck or discharging wastewater into the ground. Of course, in the latter case, you can build a simple drainage pit from scrap materials and thereby avoid financial costs, if not for one nuance: direct discharge of sewage into the ground can lead to contamination of groundwater in your and neighboring areas.

In order for “both the wolves to be fed and the sheep to be safe,” it is worth spending a small amount and building a septic tank that will clean the wastewater and make it safe. And so that the costs of its production and operation do not lead to depletion of the family budget, we recommend that you start building it yourself.

Septic tank - device, how it works

The issue of disposal of domestic wastewater suburban areas can be solved in two ways. The first consists of the accumulation and subsequent removal of sewage using sewage disposal machines, and the second covers a whole range of processes for their filtration, absorption and disinfection.

Using an airtight container for collection waste water is good option in the case when in country house or at the dacha appear on weekends and the amount of water used is small. If you plan to regularly use the bathroom, toilet and household appliances, then the volume of water increases so much that you will have to pump out the drainage pit weekly. To avoid this inconvenience, filtration-type cesspools are constructed in which liquid from the sewer is absorbed into the soil. There, with the help of bacteria, it is processed into water and safe organic substances. In fact, a septic tank is just such a structure, however, its improved design allows wastewater to be disinfected before it is discharged into the ground.

Depending on the design, septic tanks can be divided into several types:

1. Single-chamber septic tank of small volume. It is a container with an overflow pipe and is used in small households with water consumption of no more than 1 cubic meter. m per day. Despite the simple design, the efficiency of sewage treatment leaves much to be desired.


2. Small two-chamber septic tank. Consists of two containers connected by an overflow system. The simplicity and efficiency of this design makes it the most popular for DIY.
3. Multi-chamber structures. Thanks to the presence of several chambers, wastewater treatment occurs over a long period of time. This allows you to obtain output water that can be safely discharged into natural reservoirs or used for household needs. Despite the high degree of purification, multi-chamber systems are rare in private households due to their complexity and high cost.

In order to understand how a septic tank works, let's consider the most popular two-chamber design.

After the sewage enters the first chamber of the treatment plant, it is separated by gravity into liquid and solids. At the same time, the processing of organic waste by aerobic and anaerobic bacteria begins, which develop in the absence or excess of oxygen. At the same time, not only liquid waste, but also fecal matter is processed into water and harmless organic matter. By the way, the work of microorganisms makes it possible to significantly reduce the volume of the solid fraction, leaving only a small sediment in the form of sludge.

At the top of the first chamber there is an overflow channel, through which the purified liquid enters the second chamber, where it is further purified. Below the level of the inlet channel in the second tank there is an outlet pipe, from which purified liquid is taken for watering the garden or discharged into the ground. In the latter case, filtration fields or wells are installed to increase the area of ​​contact of purified water with the ground.

Advantages and disadvantages of septic tanks

The question of which is better, a cesspool or a septic tank, is best considered from the point of view of efficiency, as well as the cost of manufacture and maintenance. It is important to remember the safety of the structure.

Note that in most respects it is the septic tank that wins, which stands out for the following advantages:

• high degree of purification of domestic wastewater - the water leaving the device can be used for household purposes;
• absence of unpleasant odor in the area;
• hermetic design reduces the risk of sewage entering groundwater and makes the structure safe for the environment;
• there is no need for regular pumping - removal of sludge residue can be carried out once every few years.

The disadvantages of septic tanks include:

• more complex design;
• increase in construction costs;
• strict requirements for the use of household detergents. Conventional chemistry is destructive to microorganisms, so you will have to use special compounds;
• decrease in bacterial activity when the temperature decreases - at 4°C and below, the waste processing process stops.

Despite some nuances, the use of a septic tank allows you to preserve nature and the health of others, and this is a plus that cannot be erased by any difficulties or financial expenses.

Design and preparatory activities

The apparent simplicity of the septic tank design is very deceptive - in order for the constructed structure to be safe and productive, it is necessary to make small calculations and carefully select a location.

Choosing a location on the site. Sanitary standards

When choosing a place to install a septic tank, they are guided by the norms of sanitary and epidemiological legislation and SNiP acts:

• local sewerage structures are allowed to be installed at a distance of at least 5 m from the foundation of a residential building and 1 m from utility and commercial buildings household use located on the site;
• distance from wells and boreholes is determined depending on the composition of the soil and can range from 20 m for clay soils to 50 m for sandy soil;
• Installing a septic tank directly near roads and site boundaries is prohibited. It is required to maintain a distance of at least 1 m from the fence and 5 m from the road;

In addition, we must not forget that from time to time you will still have to use a suction pump, so it is necessary to think about how the sewage disposal truck will approach the sewage facilities.

You can do without the services of a sewer truck if you pump out the sludge using a fecal pump purchased for this purpose, and use the sludge from the septic tank as fertilizer for the garden.

Selection and calculation of material. Required volume

To install septic tank chambers, you can use both ready-made tanks and containers built by yourself:

• volumetric metal barrels;
• wells made of prefabricated reinforced concrete structures;
• plastic eurocubes;
• monolithic concrete structures;
• brick wells.

Calculation of the amount of material required depends on the volume of the septic tank, so the main calculated value is the daily amount of wastewater discharged. There is no need to accurately determine this parameter; it is enough to assume water consumption of 150–200 liters for each family member permanently residing in the house. This will be enough to use the bathroom, toilet, washing machine and dishwasher. To determine the volume of the septic tank's receiving chamber, the resulting value is multiplied by three. For example, if five people permanently live in a house equipped with all amenities, then you will need a tank designed for 3 cubic meters. m of liquid waste (5 people × 200 liters × 3 = 3000 liters).

The second chamber is calculated based on the size of the receiving tank. If its volume is taken to be equal to 2/3 of the total size of the septic tank, then the dimensions of the post-treatment chamber provide the remaining third of the structure’s volume. If we take the example discussed above, the working volume of the structure will be 4.5 cubic meters. m, of which 1.5 cubic meters. m are allocated for the second tank.

Photo gallery: drawings of future structures

When designing a septic tank, you can use drawings and diagrams of working structures.

Calculations of external dimensions are carried out using well-known geometric formulas to determine the volume of a cylindrical structure and a rectangular container.

It should be understood that in most regions the septic tank will not freeze in winter due to warm wastewater coming from the house, soil temperature and the work of microorganisms. However, the structure will still have to be deepened. The gap between the cover and the upper level of wastewater is taken equal to the amount of soil freezing in winter. It is at this depth that the drain pipe enters the septic tank. Therefore, we must rely on the fact that the calculated working volume will be below this point. In addition, with more high temperature bacteria will more actively process sewage, helping to increase the productivity of the septic tank.

Which form is better

The question of which septic tank is better - round or rectangular - can be considered incorrect, since the shape does not at all affect the performance and degree of purification. However, the configuration of the structure has a huge impact on the choice of materials. Everyone knows that round buildings are the most optimal in terms of consumption necessary funds. The septic tank was no exception. If it is made of brick, then choosing a cylindrical shape will reduce consumption by 10 - 15%. In addition, round walls perfectly resist mechanical loads from the ground. If you choose a monolithic two-chamber structure, then it is better to make it square or rectangular. Firstly, reinforced walls will resist bending forces, and secondly, this is necessary for purely practical reasons related to the manufacture of formwork for pouring concrete.

By the way, we recommend making the concrete structure yourself. If we consider the cost of a septic tank, it will not be much higher than its inexpensive brick counterparts (see table). As for the durability and strength of the structure, there can be no question of any comparison, therefore even a more labor-intensive technology will justify itself many times over. We will tell you in detail how to build a rectangular two-chamber septic tank from reinforced concrete.

Required tools and materials

To build a concrete treatment plant you will need:

• crushed stone, sand and cement for making concrete;
• steel rods or fittings with a diameter of at least 10 mm;
• metal corners, pipes or channels for the construction of floors;
• boards, timber and slats for formwork;
• film for waterproofing;
• concrete mixer;
• containers for bulk materials and concrete;
• Bulgarian;
• manual rammer;
• wood saw;
• welding machine or wire for making an armored belt;
• hammer;
• building level;
• roulette.

If it is necessary to insulate the septic tank, this list should be supplemented with the heat insulator used, for example, expanded clay chips.

Construction and installation of a country septic tank from monolithic concrete with your own hands

1. After determining the size of the structure and choosing a location, they begin to dig a pit. The size of the pit is chosen depending on what formwork will be used. If board panels are planned to be installed on both sides, then the pit is made 40–50 cm wider than the size of the tank, taking into account the thickness of its walls. In the case where concrete will be poured between the formwork and the ground, the pit is dug according to the external dimensions of the septic tank. If hired people will be used for this, calculate the cost of their work. Be sure to take into account that the soil will have to be removed from the site, and this will entail additional costs for its loading. Perhaps the total cost of all excavation work will approach the cost of operating an excavator. At the same time, he will cope with the work tens of times faster.
   

   You should not remove all the soil from the site. Be sure to leave some of it for backfilling the septic tank.

2. Compact the bottom of the hole and fill it with a layer of sand 10–15 cm thick. After this, the sand is spilled with water to compact it.
3. Install formwork around the perimeter of the structure. If a one-sided board fencing is used, then the walls of the pit are covered with plastic film. This will prevent them from falling off while pouring the walls and base of the septic tank.
4. Place pieces of wooden slats at least 5 cm thick on the bottom. They will be needed as spacers under the reinforcement belt, which will be located inside the concrete base.


5. Build an armored belt from a metal rod or reinforcement. To do this, longitudinal elements are laid on the slats, and transverse elements are attached to them by welding or tying with wire. The size of the cells of the resulting lattice should be no more than 20–25 cm.
   

   A volumetric reinforcing frame is not required in the manufacture of a septic tank: simple planar reinforcement is sufficient.

6. Fill the base of the septic tank with concrete and compact it with a bayonet or tamper. The thickness of the bottom must be at least 15 cm. To prepare a mortar from grade 400 cement, you can use the following proportion: 1 part cement is mixed with 2 parts sand and 3 parts crushed stone. When using M-500 cement, the amount of bulk materials is increased by 15 - 20%.
7. After concrete base finally set, they begin to construct the formwork for the walls and partitions of the septic tank. Reinforcement is also installed inside the formwork to strengthen the structure of the structure.
   

   If there are not enough boards to construct the formwork for the entire height, then you can use a low sliding structure, which is poured with concrete, and after it sets, it is moved upward.

8. At the level of overflow channels and the entry and exit points of sewer pipes, windows are made by installing sections of large diameter pipes into the formwork or constructing wooden frames.
9. After the septic tank chambers reach the required height, construction of the ceiling begins. To do this, support elements made of steel corners or profile pipes. It is important to ensure sufficient strength, since concrete has significant weight.
10. When installing formwork and reinforcement, take care of the openings for hatches.
11. Fill the septic tank lid with concrete and cover the structure with plastic film.
12. After the ceiling has dried, a sewer line is inserted into the receiving window of the first chamber, and the exit of the structure is connected to drainage structures.
13. The septic tank is filled with soil, constantly compacting and leveling it. It is important that the soil level above the septic tank is slightly higher than the level of the entire site. This will prevent the treatment plant from flooding during heavy rains or floods.

Arrangement of filtration structures

In order to drain purified water into the ground, use drainage systems of various types. The most common designs are filtration fields and drainage wells.

The first are a system of pipelines placed in the ground and connected to the outlet pipe of the septic tank. Thanks to the installation at an angle, the movement of purified waste through the pipes is ensured, and their absorption is made possible thanks to a system of holes and a drainage layer in which the entire structure is placed.

The latter are a special case of a cesspool without a bottom and can be constructed from perforated concrete rings, bricks laid in checkerboard pattern, or old car tires. To ensure absorption capacity, the bottom of the filtration well is covered with a thick layer of crushed stone. It must be said that, unlike a cesspool, the performance of a structure connected to a septic tank practically does not decrease over time. This is due to the absence of solid particles and suspensions that can clog drainage holes and pores.

When using a septic tank, it is necessary to radically reconsider the approach to the use of sewerage. From the day the system is put into operation, it is prohibited to use chemical detergents and pour any aggressive substances into the toilet or sink. It must be remembered that wastewater treatment is now carried out by living beings - bacteria and other microorganisms. Of course, this does not mean that for washing and cleaning you will now have to use ash and simple laundry soap, like our ancestors. When using household detergents marked “Bio” or “Eco”, nothing will threaten the fragile ecosystem of the septic tank, and you will get good results when cleaning and washing.

Inorganic waste and garbage should not be poured into the sewer - there is a trash can. Getting into the drive wastewater treatment plant, they will collect at the bottom and interfere with its normal operation, and when pumping out sludge, they can clog the hoses of the fecal pump.

To improve the performance of the septic tank, special bioactivators are periodically added to the receiving chamber, which include several varieties of aerobic and anaerobic bacteria. When choosing biological products, you must pay attention to their purpose, since such compositions are produced both for normal conditions operation, and for cleaning heavily contaminated walls of septic tanks, drains with an increased fat content, etc. By the way, the compositions must be used exactly as indicated by the manufacturer on the packaging, otherwise the bacteria may die.

From time to time you will have to check the level of sediment. The fact is that their accumulation leads to a decrease in the useful volume and a decrease in the productivity of the septic tank, so periodically the sludge will need to be pumped out or removed using a sludge pump, a fecal pump or a long pole with a scooping device. Of course, mechanized pumping methods will be preferable.

Video: homemade concrete structure for a private house

Despite the fact that the process of manufacturing a septic tank is associated with certain time and material costs, in the future, a sewage treatment plant built with your own hands will pay for itself more than once. You don’t have to constantly think about the fact that the sewage system may “stand up” at the most inopportune moment or worry about regularly pumping out the container. The septic tank will be able to function for many years without polluting environment and without causing any problems.

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Types of septic tanks for a private home: plastic, concrete brick

Septic tanks are classified into several types. Based on the materials used to manufacture the containers, they can be:

• plastic - this is a ready-made septic tank for a private home;
• brick ones are the most inexpensive septic tanks;
• Concrete are the most reliable and durable sewer wells.

Making a septic tank out of brick is the most affordable way arrangement drain hole. It does not require the work of loading equipment (as when working with heavy concrete rings) and costs the optimal amount of money. You can do it yourself; you don’t need professional construction experience for the work.

A concrete septic tank is constructed from ready-made well rings. They are loaded into the pit using lifting equipment. Reinforcement is installed between the rings as steps for descending into the pit. This is the most reliable and durable arrangement sewer well. It requires cash costs and the possibility of access by a loading and unloading crane.

To quickly equip the sewer system, purchase ready-made plastic or metal containers. A plastic septic tank is cheaper than a metal one, and is also not subject to corrosion, is lighter in weight and easier to install. The resistance of plastic to the aggressive effects of acids and alkalis, as well as the average price, have made plastic septic tanks popular among other storage tanks

Classification of septic tanks according to operating principle

Based on the principle of operation, septic tanks are classified into three groups:

• Cumulative - collect sewage and prevent it from entering the ground.
• Absorbable - collects wastewater, partially filters it and dissolves it in the ground, where the wastewater is finally purified.
• Bioseptic tanks completely purify wastewater and produce water that can be discharged into an open reservoir.

Storage septic tanks

The storage design of the septic tank assumes that its container collects all the sewage and stores it until it is pumped out by a sewer truck. Storage septic tanks are the most impractical types of autonomous sewage systems. Firstly, they require frequent pumping, which means money costs. Secondly, storage septic tanks pose the question of strict water conservation to homeowners. Otherwise, the contents of the pit will have to be pumped out every month.

Storage structures are justified if two separate septic tanks are built (one for the toilet, the second for other drains). In such sewer systems, a storage septic tank can be a container for collecting feces. All other wastewater, the volume of which is much larger, will be absorbed into the ground or soil after settling and filtration.

Absorbable septic tanks with soil post-treatment

A septic tank with wastewater resorption into the ground is more profitable than a storage tank:

• Such a system does not require frequent monitoring of operation. With the correct volume of the sewer tank, wastewater is absorbed into the soil through the bottom of the hole without filling it to the top.
• There is no need to call a sewer truck to pump out wastewater. This means lower costs for sewerage work.
• The construction technology is simpler, since there is no need to make the septic tank completely sealed.
• It is cheaper to lay the walls of the pit with bricks with your own hands than to purchase a plastic container for installation in the ground

The advantages of the design border on its disadvantages. We list the most important disadvantages of septic tanks with soil post-treatment:

• Possible contamination of groundwater and soil. Therefore, such a sewer system cannot be placed close to the coastline, in the water protection zone, where soil water passes close to the surface.
• For high-quality absorption of treated wastewater, the soil must be sandy. In clay layers of soil, wastewater is not absorbed, the septic tank becomes accumulative and requires periodic pumping.
• The drainage pit is located at least 5 m from residential buildings. Therefore on small areas There is often not enough space to build such a sewer system.

Bioseptics

These are septic tanks with deep wastewater treatment. Sewage treatment uses mechanical filtration and sedimentation, biological treatment and chemical disinfection. The listed operations are performed in separate chambers.

A two-chamber septic tank without pumping works as follows: wastewater accumulates in the first chamber. Here, primary filtration and separation of heavy suspended matter from the wastewater occurs (they accumulate at the bottom). After settling the wastewater, the liquid enters the second chamber (by gravity), where it is purified by aerobic and anaerobic bacteria. An aerator (a device for saturating water with air) periodically works here. It provides conditions for the work of aerobic bacteria. Heavy suspensions from the first treatment chamber are disinfected with chemical reagents.

Advantages of bioseptic:

• Wastewater treatment in a bioseptic tank is so deep that after purification the water can be discharged into an open reservoir.
• A bioseptic tank can be built in any convenient place: near the house or on the shore of a reservoir. The storage structure is equipped with drainage pipes and an electric motor for periodic pumping of purified water.
• The bioseptic tank can be constructed on any soil. They are not absorbable sewage and do not require good soil porosity. Therefore, the storage tank can be installed either on sandy soils, and in clays and loams.

Disadvantages of bioseptics:

• These are volatile devices. They require support for their operation. electric shock. Which is not always possible and requires money.
• High price (up to 70,000 rubles for a septic tank + cost of delivery, ground work).

Installation of a septic tank in a private house

In private homes, the most popular are septic tanks with filtration and wastewater resorption. How does a septic tank work in a private house if wastewater is further treated in the ground?

An absorbable septic tank looks like a cylinder without a bottom. The septic tank is completely buried in the soil. The bottom of the septic tank is below the freezing line. Burying the septic tank several meters into the ground ensures that it does not freeze at any time of the year.

The water is drained into the container near the surface of the earth. Sewage is transported to the pit through pipes that are buried in the ground above the frost line. The slope of the pipes does not allow water and feces to stagnate and freeze even in severe frosts.

The bottom of the septic tank is covered with a layer of filter material (crushed stone, sand). When digging a hole for a septic tank, they try to go deeper into the sand layer. Sandy soil quickly absorbs water, which ensures timely removal of waste from the pit.

The pit is covered from above with a concrete slab (floor slab with a sewer hole) or a metal sheet. The tightness of the internal container controls the penetration of unpleasant odors out into the yard space next to the septic tank.

Scheme of a resorbable septic tank

Volume and dimensions of the septic tank

The volume of the septic tank depends on the number of people living in the house and the intensity of use of plumbing fixtures. If there is a family of 2 adults in the house, and they use a shower and rarely take a bath, then the water consumption will be minimal, which means that the volume of the sewer tank will also be small (2-3 cubic meters). If a large family lives in the house, with small children and lovers of a daily bath, then the water consumption will be increased, which means the volume of the sewer septic tank should be 6-8 cubic meters. How is the size of a sewer pit calculated?

Water consumption standards and septic tank volume

Calculating the volume of a septic tank for a private house takes into account the number of people and the daily water consumption rate. The standards of the 80s of the last century used an indicator of water consumption per person - 150 liters per day. The indicated 150 liters were generated from water consumption for kitchen preparation, washing dishes and flushing the toilet. If you add to it the water consumption for a daily bath and periodic washing, the consumption will increase to 250 liters per day (per person).

Official monthly water consumption standards are 2.4 cubic meters per person (in an apartment) and 5.7 cubic meters per person (in a house with hot water supply). These standards are underestimated and are used to calculate preferential cubic meters, for which the state takes 50% of the payment. The simplest calculations show that full use of water and modern household appliances requires more water consumption - up to 9 cubic meters. water per person monthly.

Effluent in a septic tank: rate of resorption

The volume of the septic tank must take into account the daily water consumption and the rate of absorption of wastewater. If the soil is clayey, the resorption of wastewater will occur slowly, the pit will fill with sewage water and require pumping. If the soil is sandy, the runoff will be absorbed within several days.

If we assume that the resorption rate is 3 days, and the water consumption rate is 250 liters per person, then for a family (4 people) the required volume of sewage tank is equal to:

4 people * 250 l/day. * 3 days. = 3,000 l or 3 cubic meters.

For a supply, purchase a larger septic tank - 5-6 cubic meters per family (4 people).

Septic tank dimensions

The dimensions of the hole for installing a septic tank depend on the previously calculated volume and shape of the hole in the ground. Geometric formulas are used for calculations.

The volume of a cube is equal to the product of its faces or V = A*B*C, where A, B and C are the length, width and depth of the cesspool.

The volume of the cylinder is equal to the product of the area of ​​its base and the height or V = 3.14 * R2 * H, where R is the radius of the round bottom, H is the height of the cesspool.

If the volume of the septic tank should be 6 cubic meters, then for a rectangular pit its dimensions can be 1 * 2 m - area and 3 m - depth. The cylindrical container or pit can have a diameter of 1.6 m and a depth of 3 m.

Installation of a septic tank

Installation of a sewer tank begins with ground work. In the place chosen for arranging the drainage pit, the soil is removed. The dimensions of the pit should be 20-30 cm wider than the perimeter of the septic tank on each side.

The method of installing a septic tank depends on its type and material. How to properly install a concrete septic tank?

Installation of concrete rings

Concrete rings for the sewer pit are installed using a crane. If the access of special equipment is difficult, then the rings are rolled to the site of the future drainage well and installed simultaneously with the excavation of the soil. You can see how this is done in the video. It shows the process of constructing a drinking well. The technique for installing concrete rings without a crane is the same for a drinking tank and a septic tank.

The ring is placed on the soil surface and the layer of soil inside the ring and under its walls is removed. So, layer by layer, the soil is removed and the hole is deepened. In this case, the concrete ring falls down under its own weight. When the 1st ring is at soil level, the 2nd is installed on top of it, and so on, all subsequent rings of the concrete well. After excavating the last layers of soil, the bottom of the pit is covered with crushed stone and sand. The total thickness of the layer of filtration materials should be 30 cm.

Installation of a plastic septic tank

Plastic has low strength characteristics. Therefore, it is not recommended to install plastic containers directly into the ground. They are placed inside a pit with concrete (or brick) walls. The pit is concreted after excavation (reinforced with metal reinforcement and filled with concrete or lined with brick). This design increases the cost of the sewer system, but guarantees its durability and operational reliability.

A small septic tank is installed without a concrete “room”. The space between plastic wall and the hole is covered with sand. To do this, place a plastic container in a hole and fill it with water. If you pour sand without filling the septic tank with water, the plastic container will be squeezed up when filling.

Sand filling acts as a load absorber. In addition, it quickly drains water, so the material of the septic tank and the space next to it does not get wet and does not expand when freezing, which means it does not push the container up from the ground.

The next element of safe installation of plastic “barrels” is concreting the bottom and attaching the septic tank to the concrete. This “anchor” prevents the lightweight plastic container from being pushed out of the ground when the soil freezes in winter.

Making a brick sewer pit with your own hands

The most affordable way to install a sewer system personal plot- this is to make a cesspool lined with bricks. To do this, take out the soil, place it a few meters nearby and begin bricklaying. Even a layman can lay a cesspool with bricks. A perfectly flat laying plane is not required here. However, it is necessary that the brick wall is strong and does not collapse during operation of the septic tank.

The bricks are laid out at intervals, that is, in a row, after 1-2 bricks, an empty space of 0.5 or 1 brick is left. Such rows alternate with rows of solid masonry. After 10-15 rows, metal reinforcement is placed between opposite walls. It not only acts as steps for descending into the pit, but also acts as a spacer for the opposite walls and increases the strength of the “leaky” brick structure.

The top of the well made of bricks is covered with boards and concreted. A small hole is left between the boards through which you can go down to preventive examination. This hole is covered with a metal sheet and covered with earth. If necessary, look into the septic tank, the soil is raked and metal sheet lift.

Which septic tank to choose: compare materials and cost of work

The criteria for choosing a septic tank are based on the operating conditions of the sewerage system and the total cost of work on arranging the wastewater disposal. The optimal choice combines the durability of the structure with the affordability of work and materials. The most inexpensive sewerage installation will cost you 1000 bricks and 2 bags of cement for mixing masonry mortar. The remaining costs will be covered by your own labor and personal time.

The most reliable and durable concrete septic tank will be estimated as the cost of 5-6 concrete rings and payment for their transportation and installation. To this it is necessary to add the cost of ground work - excavation of 6-10 cubic meters of soil (unless this work is done by hand).

The fastest sewer system is a plastic container, cheaper than concrete rings, but much more expensive brickwork. The cost of plastic septic tanks depends on their volume and ranges from 20,000 to 40,000 rubles. This also includes ground work, concreting the bottom and work on installing a septic tank in a pit. The total cost of installing a sewer system with a plastic septic tank is estimated at 80,000 rubles.

The cost of an autonomous bioseptic tank is 60,000 - 70,000 rubles. (without installation and ground work).

The construction of a septic tank can be done for different purposes (drains from a toilet or all drains from a house), from various materials, with my own hands or the work of professionals. The choice is yours.

ksportal.ru

Septic tank volume: a fundamental concept

Any septic tank has several chambers. This means that in order to find out how many cubic meters are in the septic tank, you need to add up the volumes of all these compartments. Also, you need to take into account that the calculations take the distance from the bottom to the pipe level. For example, if the volume of a two-chamber septic tank is calculated, then:

• for the 1st chamber it is important to know the size of the gap between the bottom and the overflow pipe passing between the chambers;
• for the 2nd chamber, the distance between the bottom and the pipe for discharging purified water into a drainage well or filtration field is taken into account.

Important! In the first chamber of the septic tank, solid deposits will occupy about 20% of the entire height of the space. This factor must first be included in the calculation of a septic tank for a private house, at the stage of calculating the volume of only the liquid component of the wastewater.

How to calculate a septic tank - regulatory framework

So, the volume of a septic tank for a summer residence (house, cottage, mini-workshop) is a value directly proportional to the amount of wastewater generated. According to the current SNIP, the norm is 0.2 m3 or 200 liters per person per day. And when calculating, the volume with a 3-day supply is taken. This means that the minimum estimated volume of wastewater per person is 0.6 m3.

On the other hand, the same SNiPs indicate that purified water can only be discharged into the landscape after 14 days have passed from the moment it enters the facility. It is during this period that the water will settle, and anaerobic bacteria will do their part of the work of breaking down organic inclusions.

Attention! The volume of a septic tank for a private house must be at least 2.8 m3. This figure is calculated by a simple mathematical operation: 0.2 m3 per day x by 14 (the period the wastewater is in the septic tank).

Required volume of septic tank: practical experience

The norm of 200 liters of wastewater per day per person is rarely achieved in real life - this is the maximum possible figure. Team "New Place" on Russian market treatment facilities have been operating almost since its inception. Based on our experience, we can say that the average daily volume of wastewater per person is about 0.1 m3, that is, 100 liters. Modern homeowners take a very thoughtful approach to resource consumption. They also use water sparingly. Data from practice are 2 times less than the normative ones. And to calculate a septic tank for a home, with optimal indicators, you can take the figure of 150 liters per day per person as a guideline. So, to say with a focus on intensive use household appliances, which are the source of wastewater formation. Naturally, the septic tank is calculated based on the number of residents. For example, for an average family of 4 people, a treatment system with a capacity of at least 6 cubic meters is required.

When savings are not justified

When discussing the situation, what volume of septic tank is needed in a particular area, we never recommend reducing functionality object “butt-to-face” with real drains. In the construction industry, saving resources must be approached with extreme caution. This is explained by the fact that even in domestic wastewater There are many inclusions that are difficult to digest by anaerobic bacteria. And they cannot break down some substances at all. We mean, first of all, such complex compounds as fats.

Our task, as professionals, is to select the optimal volume of a septic tank for a private home so that the structure can effectively clarify wastewater. This process involves the settling of suspended particles to the bottom. They are subsequently processed or pumped out using a sewage disposal machine, and the purified water is discharged according to a scheme previously agreed upon with the client.

Important! Calculation of the volume of a septic tank for a private house should be focused on normal indicators in the direction of increase. In this case, you can count on the fact that the structure will effectively cope with the assigned tasks, and there will be no problems with its maintenance. Otherwise, silt deposits and fats, after being drained into the drainage well, will quickly clog the soil, and the water will stop going further for filtration, that is, the sewage treatment system will fail. In a word, you need to save “a little in reserve.”

Calculation of septic tanks: how many chambers should there be

Above in the text, emphasis has already been placed on the fact that the more cameras there are in a structure, the more efficiently it functions, providing a purification rate of up to 98-99%. This must be taken into account before calculating the volume of the septic tank for your home.

From the point of view of SNiP, the technical characteristics of treatment facilities can be updated as follows:

• A septic tank with one chamber is allowed with a wastewater volume of 1 cubic meter.
• At least two chambers are required for volumes up to 10 cubic meters.
• But over 10 m3, three-chamber septic tanks are shown.

Important points

For wastewater, the number of chambers it has to overcome does not matter. The time spent in each of them is much more important. This parameter is determined by the calculation of the septic tank for the house. In this case, the number of cameras is not important, the main thing is the total volume of the object.

Organic waste inclusions do not care how many sections are present inside the septic tank. If there is only one chamber, then the suspended particles will settle unevenly and some of them will go further into the drainage well or filtration field. And to say that this degree of purification is sufficient and there is no need to reuse the water at all. With two or more sections, the efficiency of the structure increases significantly.

We understand that it is quite difficult to calculate the volume of a septic tank for a consumer who has never encountered such a task. Therefore, we recommend that you act in such a situation in the only rational way - contact the contact line of the “New Place” company. Already during the first telephone consultation, our specialists will answer most of the questions that arise.

www.novoe-mesto.ru

It should be noted that the volume of a septic tank is the sum of the volumes of all its chambers. The volume is also calculated from the bottom to the pipe level. For the first chamber - from the bottom to the overflow pipe between the chambers, and for the second chamber - to the drain pipe into the drainage well or onto the filtration fields.

It should also be taken into account that in the first chamber the average height of solid deposits will be 20% of the chamber height. This volume must also be subtracted from the calculations if we are talking only about the liquid component.

Calculation of septic tank volume.

The required volume of a septic tank is directly proportional to the amount of wastewater.

SNIP indicates that when calculating wastewater volumes, the daily water consumption per person should be taken in the amount of 0.2 cubic meters. per day (200 l/day). And the volume should be calculated based on a 3-day supply. Then the minimum volume for one person is 0.6 cubic meters. For a family of 4 people - 2.4 cubic meters. Taking into account bottom sediments - 2.7 cubic meters.

Please note: sanitary standards indicate that the discharge of water from a septic tank into the soil (into a drainage well) should occur no earlier than 14 days from the moment it enters the septic tank. Those. settling of water and its purification by anaerobic bacteria in a septic tank should take place for at least two weeks.

Based on these statements, you will need a “giant” septic tank - 2.8 cubic meters for one person. (0.2x14). Accordingly, for a family of 4 people – 11.2 cubic meters. (4x2.8), which generally does not correspond to reality.

It should be noted that the wastewater flow rate of 200 l/person per day specified in SNIP is not always achieved in practice. With economical use of water, which is becoming typical for a private house, the volume of wastewater will be more likely 0.1 m3. per day (100 liters) per person. Then the septic tank is “very economical” and does not meet the requirements of the standards (may be rejected by the sanitary services), but nevertheless works for 4 people, maybe 1.5 cubic meters. But this, again, for your information, such septic tanks cannot be built.

Savings during construction are not always profitable. The wastewater is full of substances that are difficult to process by anaerobic bacteria or are not processed at all. First of all, these are heavy fats. It is important to construct treatment facilities in such a way that sufficient clarification of the water occurs in the septic tank. So that heavy substances and fat would settle to the bottom and be processed or removed later in the form of sediment by a sewage disposal machine.

Increasing the volume of the septic tank will always have a positive effect on the quality of water treatment and its maintenance.

Therefore, irresponsible reduction of septic tank volumes is not acceptable at all.

Number of cameras

When choosing the volume of the chamber and their quantity, you also need to take into account the tank volume of a small sewer truck - 3.75 cubic meters. And also the operating depth of the suction pump is up to 3 meters. The working volume and depth of the first chamber should not exceed these values.

In principle, increasing the number of chambers has less effect on the quality of purification than the entire volume of the septic tank. The residence time of the waste is important - at least 3 days. As well as the composition of the water leaving the septic tank.
You can also read How a septic tank should work properly

Consequently, to achieve the minimum volume of a septic tank for an “average” house of 2.7 cubic meters. it is also possible with a single-chamber septic tank (for example, this volume is achieved by two reinforced concrete rings with a diameter of 1.5 m).

But if we remember the recommendations of sanitary standards, and the issue of preserving the soil and environment near the house, and also the fact that wastewater can be “difficult” especially when operating washing equipment and an extra 1 - 2 days of settling is necessary, then of course it is better to increase the volume, improve the quality of wastewater, and of course use a two-chamber septic tank, even for this case.

A single-chamber treatment facility with filtration through the bottom (essentially a cesspool), according to the standards, can be done only with a very small flow, when the sewerage system is used only occasionally in the country.

Which design option to choose

Let's consider the most common designs of septic tanks - made of reinforced concrete rings.

The standard ring height (most often used) is 0.9 meters.
The volume of one ring with an internal diameter of 1.0 meter will be 0.7 cubic meters. (0.5x0.5x3.14x0.7=0.7065).
With a diameter of 1.5 meters - 1.59 cubic meters.
With a diameter of 2.0 meters - 2.83 cubic meters.

The depth of the drain pipeline at the entrance to the septic tank can be of different sizes. It depends on the length and the specified slope. It is recommended not to bury yourself in the ground; it is more profitable to use insulation. At the same time, do not place the septic tank more than 10 meters from the house. But make the slope at least 3% - it insures against freezing and clogging.

Let us assume an average pipeline depth of 0.5 meters with insulation. Then the depth of the overflow pipeline from the first chamber to the second should be already 0.7 meters. The septic tank is insulated on top with extruded polystyrene foam with a thickness of at least 50 mm.

Thus, when using 1.0 meter rings, 2 pieces per chamber, you can achieve a two-chamber septic tank volume of 2.7 cubic meters.

And the use of 1.5 meter rings in this case makes it possible to build a single-chamber septic tank of the required volume (for our example).
But naturally, a design with a reserve in terms of volume and number of chambers is objectively better, for example, the first chamber has 2 reinforced concrete 1.5 meter rings, the second has 2 rings but with a diameter of 1 meter. Another question is how much money should be saved during construction...

More information about the construction of a septic tank can be found here

stroy-block.com.ua

Regulatory Requirements

The sewage system of a private house consists of several key elements:

1. Discharge points for sewage and waste.
2. A system of drainage and sewerage pipes in the building itself.
3. Pipes below the surface outside the structure.
4. A septic tank whose volume is sufficient for the functioning of the system as the final point of “reception” of waste and its treatment.

The most important steps before starting installation work:

1. Determining the location of elements of the sewer system.
2. Preparing a plan.
3. Calculation of the size, volume and other parameters of the septic tank.
4. Preparation of materials.

Since all waste will be collected at the end point of the system, calculating the volume of a septic tank for a private home is a key preparatory stage. Errors during this procedure will have disastrous consequences, which will result in permanent system failures.

When developing the plan, it is important to take into account the sanitary requirements for the distance of the septic tank from key objects on the site. These requirements are set out in SNiP 2.04.03-85 “Sewerage. External networks and structures.” Regulatory requirements can seriously affect the calculations, since everything depends on the size land plot. If the area is small and the number of people living is large enough, problems may arise with the installation of an autonomous sewer system.

The key characteristics of remoteness that must be familiarized with and taken into account when planning include the following parameters:

1. Distance from a residential building.
2. Distance from a drinking well, well or other source of artificial or natural water, taking into account the carrying capacity of the soil.
3. Delineation with plantings of vegetation.
4. Taking into account distance from neighboring areas.
5. Distance from transport routes for access to the tank of the sewer truck, compliance with distance requirements to protect systems from vibration.

Dimensions and volume

Calculation of a septic tank involves determining:

• body size of a factory or homemade container;
• container volume;
• daily volumes of waste and sewage discharge;
• daily water consumption for each consumer living in a residential building;
• quantity of materials and means (especially important when independent device septic tank).

The key parameter of all calculations is the number of people planned to live in the house; permanent, seasonal or temporary residence.

The best option is to install a special factory-made septic tank. But if you are planning to install an autonomous sewer system in a dacha, where you rarely visit or are limited in finances, the option with self-production septic tank made of brick, concrete rings or even tires.

According to SNiP, the size of a septic tank per living person is: depth should not be less than 130 cm, width and length should not be less than 100 cm, depth from the surface to the bottom of the tank should not be more than 320 cm (subject to mandatory maintenance with special equipment for systematic cleaning).

It is worth distinguishing between the dimensional characteristics of the septic tank body itself and the pit, which must accommodate the tank, pipes, compressors and other elements of the system. Indicators of daily waste discharge and water consumption are necessary to determine the parameters of the container itself.

With a factory septic tank consisting of several chambers, everything is quite simple - all the necessary parameters and calculations are indicated in the technical documentation for the tank. If there is limited space on the site, a large number of people living and independent equipment of the septic tank, additional detailed calculations will be required, taking into account all factors.

For these purposes, specially developed septic tank calculation tables are used:

1. Table of liquid consumption by one consumer for 24 hours.
2. Table of average daily water consumption for one person.

According to the table, it turns out that for one person in a residential building it is necessary:

• 125-160 liters of cold water.
• 160-230 liters of water with a water heater.
• 230-350 liters of water with a centralized hot heating system.

Calculation of dimensions and volume

To accurately determine the internal space of the tank, a specially developed formula for calculating the volume of the septic tank is used. But it implies a large number complex meanings and difficult for private practical application. In practice, the volume of a septic tank for a private home is calculated using a simpler formula. Number of people X 200 liters of wastewater per person X 3 days (wastewater processing time) / 1000 = volume in cubic meters. Most often there are 4 people in a family. Let's consider the option of calculating the volume for this number of family members. 4x200x3/1000=2.4 cubic meters. m. A septic tank for 5 people will require a volume of 3 cubic meters. m. The volume calculated by this formula for 6 people is 3.6 cubic meters. m. For 20 people, the calculated figure is 12 cubic meters. m.

When calculating, it is better to take the “number of people” parameter “with a reserve” to take into account the load when visiting guests and other unforeseen situations. Daily norm may be increased if there are small children or pets. This figure also increases if you use a large number of different household appliances that use water (washing machine).

As mentioned above, there are laboratory calculations that are given for factory septic tanks. Using these data, it is possible to carry out calculations in situations with containers made independently.

So, with a septic tank in three sections:

• for two people you will need a useful volume of 1.5 cubic meters. m.;
• for three to four people - 2 cubic meters. m.;
• for five to six people - 3 cubic meters. m.;
• for eight people - 4 cubic meters. m.;
• for ten people - 5 cubic meters. m.;
• for twenty people - 10 cubic meters. m.

The main building material when constructing a septic tank yourself is concrete rings. And the key calculation is to determine the amount of these materials. Most often, 3 reinforced concrete rings with a diameter of 1.5 m and a height of 0.9 m are enough. More than 5 rings are not used per septic tank.

Don't forget about other elements when independent arrangement systems. These include:

1. Reinforced concrete slab.
2. Pipe for ventilation.
3. Cement, sand, crushed stone.

When calculating the required volume of a septic tank, the formulas given above are used. In addition, it is necessary to know the volume of one ring in order to determine a sufficient number of rings in the container.

The ring is a conventional cylinder, and its volume is calculated using the appropriate formula.

V=∏R2H=∏(d2/4) H, where:

• V – cylinder volume;
• ∏ - Pi number (3.14);
• R – base radius;
• d – base diameter;
• H – height.

Knowing the volume of the ring, it can be compared with the obtained figures for the required volume of the concrete septic tank. The volume of 1 ring (d=1.5 m; H=0.9 m) is approximately 1.6 cubic meters. m. It turns out that for 4 family members in a house with all the amenities (hot water supply, etc.) you will need 2 rings to install a septic tank.

This quantity will be enough for 5 people. Up to 10 people can be provided with one 3-ring container. If you plan to accommodate from 10 to 20 people, you will need to install a septic tank consisting of several containers, since more than 3 rings cannot be installed. In this case, it is better to take care of purchasing a factory model of sufficient volume.

vodospec.ru

Living in your own home will be comfortable if the owners provide all the necessary conditions for this. Few people are already attracted to the options of delivering water in buckets from a well, with a wooden toilet on the site. All this is acceptable for dacha conditions with periodic weekend visits, but it looks like a complete anachronism if the family lives in the house permanently. This means that normal housing must be equipped with water supply and sewerage. It is good if the locality has the ability to connect to central highways and collectors. But such cases are quite rare, and more often it is necessary to create completely autonomous systems.

Water supply is a separate multifaceted topic, and in this case we are interested in creating 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, and clarifying wastewater. In the practice of private housing construction optimal solution This issue is the use of special containers - septic tanks. Such an autonomous sewerage element can be built on our own or purchase it ready-made. This publication will discuss how to choose a factory-made septic tank, that is, what criteria for evaluating the product should pay special attention to.

What is a septic tank? The principle of its operation

Septic tank – essential element 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 to collect all sewage from a house (group of houses), settle it and carry out preliminary biological treatment of varying degrees of depth. The wastewater that has gone through this cycle is discharged into ground filtration devices or structures, or is subject to regular pumping using special equipment. In any case, it prevents the entry into the environment of contaminated wastewater that poses a chemical and bacteriological danger to it.

In fact, a septic tank is always isolated from the ground storage capacity, and may consist of one or more cameras. The diagram of the simplest single-chamber septic tank is shown in the figure:

Sewage from the house flows through the pipe (item 1) by gravity, for which a certain slope is observed when laying (about 5° or 20÷30 mm difference for each linear meter pipes). The septic tank chamber (item 2) has reliable waterproofing or is made of completely waterproof materials.

Solid inclusions, under the influence of gravitational forces, settle to the bottom in the form of sludge (item 3). Those impurities that have a density lower than that of water, on the contrary, float to the top, forming a film or crust. Thus, spontaneous stratification of wastewater occurs.

In the same chamber, processes of biological decomposition of human waste constantly occur. Special anaerobic bacteria help to activate these biochemical reactions, which process organic matter into inert mineral sediments, gases that are discharged outside, and clean water. At the same time, this should lead to the death of all pathogenic microflora.

The water that has received such cleaning and clarification is transferred through the overflow pipe (item 4) to the filtration section. Water intake is organized so that it is carried out from the central part of the stratified liquid, preventing overflow of the floating crust. To do this, the gully is equipped with a vertical section that is constantly immersed in water.

Final soil purification can be organized in various ways. In this case, a filter well (item 5) with a drainage layer at the bottom is shown. However, this can be an underground filtration field using special perforated pipes. and Filter or absorbent trenches are used. You can purchase a special infiltration unit, the so-called “tunnel”. The choice of a specific type of final soil filtration depends on the level of wastewater treatment, type of soil, height of groundwater, depth of soil freezing, etc. – in any case, a specialist’s recommendation will be required here.

The filtration module (well, tunnel, field, etc.) is no longer considered as a septic tank chamber - it is the final link in the autonomous sewerage chain. Sometimes, when using septic tanks with multi-level treatment, they even use storage tanks, the water from which can be used, for example, for irrigating a personal plot.

Single-chamber septic tanks, it must be said, do not have a high degree of wastewater treatment. They are usually used for small volumes of wastewater (not exceeding 1 m³ per day) and in the event that it is not discharged into the septic tank. fecal sewer. Otherwise, it simply will not cope with its direct task of complete cleaning before infiltration, and the sewage disposal machine will have to be called too often for pumping.

The optimal solution is multi-chamber septic tanks. An example is shown in the diagram:

Sewage through a pipe (item 1) enters the primary chamber (item 2), which in this case serves mainly to settle the liquid, separating it into light and heavy insoluble fractions. This is where the main volume of silty sediment accumulates (position 3).

Through an overflow pipe (item 4) with a blocking system (hydraulic seal), the wastewater that has partially undergone initial treatment enters the second chamber (item 5). This compartment (often called a methane tank) is intended for biological treatment water under the influence of anaerobic bacteria. Chemical organic components decompose into a solid insoluble neutral sediment (item 6), water and a gaseous component, which exits into the ventilation pipe (item 10). This achieves a much higher degree of purification of any household wastewater, including fecal matter.

Next, through the overflow pipe (pos. 7), the purified water passes either into an infiltration device (in this case, a well is shown, pos. 8), with a filled drainage layer (pos. 9), or into the third chamber of the septic tank, where final clarification occurs and fine settling.

Often the second or third chamber is used for finer cleaning with aerobic microorganisms, which involves saturating it with oxygen - aeration, that is, periodically passing small air bubbles. For this, septic tanks are equipped with special aerator compressors, which, however, will require a power supply.

To equalize the pressure in the septic tank compartments, they are connected by an air channel (item 11). Inspection and cleaning necks, closed with hatches, must be provided.

If increased requirements are imposed on the level of water purification (for example, for the possibility of its reuse for technical purposes or if such conditions are put forward by the local sanitary and epidemiological service), then the septic tank can also be equipped with a biofilter with a special mineral or polymer filler. A biofilter can be one of the structural elements of the last chamber of the septic tank, itself be such a final compartment, or it can be a separate module that is installed after the septic tank in front of the filtration field or storage tank for purified water.

In septic tanks with a biofilter, the highest degree of purification of water from sewage is achieved, and such systems can practically be classified as local treatment plants (LTPs). Naturally, the cost of such installations is very high.

In the conditions of individual construction, septic tanks were most often made of reinforced concrete rings or constructed independently by digging out the necessary containers and cementing their walls. Both options have a characteristic drawback - the difficulty in ensuring complete sealing of the septic tank chambers from the surrounding soil, the need for constant monitoring of the condition of joints, pipe passages, etc.

But nowadays a wide range of ready-made engineering solutions made from modern materials are on sale. Most often this is a multi-chamber design assembled in one housing, but it can also be modular.

Septic tanks differ in total volume, performance, dimensions, material of manufacture, layout, and other parameters. All this is important to consider when choosing a specific model.

Where is it allowed to place a septic tank?

Before purchasing a septic tank, you need to decide in advance where it will be installed. Not only is this very often a very impressively sized structure, but the location of such treatment plant must comply with certain rules prescribed by regulatory documents - SNiP 2.04.03-85, 2.04.02-84 and 2.04.01-85, SanPiN 2.1.5.980-00 and 2.2.1/2.1.1.1200-03. If desired, all these documents can be easily found on the Internet.

• These requirements were not invented out of nowhere - any septic tank is an object of potential environmental or man-made threat, which may include the following:
• Flooding of the soil and foundation of buildings and structures due to a violation of the tightness of the container itself or the pipe connection.
• Contamination of the site in the event of a tank overflow, for example, due to untimely pumping out of accumulated silt deposits or due to natural phenomena - floods, heavy melting of snow, prolonged rains.
• Penetration of liquid waste and the microbiological cultures it carries into water sources or nearby aquifers.
• Penetration of unpleasant odors into living spaces.
• Poisoning of the fertile soil layer by organic matter, leading to the death of plants.

So, when choosing the location of the septic tank, adhere to the following standards:

• The distance to the foundation of a residential building must be at least 5 meters, from other outbuildings - at least a meter. In exceptional cases, when a closed-type VOC with complete biological processing of waste is used, the distance to a residential building can be reduced, but this issue requires additional approval.
• The most important parameter is the distance of the septic tank from the water source. If this is a well fed from the upper aquifers, then the distance should be about 50, and sometimes, with light sandy soils, even 80 meters. The distance to a deep water well is at least 25 meters. If the terrain of the site allows, then the septic tank should be installed lower on the slope - this will significantly reduce the likelihood of wastewater penetrating into aquifers.

The exact distance must be determined individually each time, based on a study of the soil and the existing relationship between the aquifer and its filtering layers.

• Water pipes should not pass closer than 10 meters from the septic tank.
• The minimum distance from a standing body of water (lake, reservoir, pond) is 30 meters, from a surface stream or river - 10 meters.
• If there is a busy highway near the house, then the minimum distance from it is maintained at 5 meters.
• There should be no trees or bushes around the septic tank within a radius of 3 meters. Firstly, plants can become intoxicated from oversaturation of the soil with organic matter and die. Secondly, such a distance prevents the possibility of damage to the container by the root system of trees or bushes.
• A distance of at least 2 meters from the border of the neighboring plot should be provided. And at the same time, of course, all of the above standards must be observed, regardless of the fact that the buildings, trees, water intake points are not yours and are located behind the fence. In general, of course, in order to avoid misunderstandings in the future, the installation of a septic tank should be “amicably” agreed upon with the neighbors.

As you can see from the listed requirements, finding the optimal place to install a septic tank may not be so easy. It should also be taken into account that for regular pumping it is necessary to provide an access road for a sewage disposal truck.

If the optimal location is found, this does not mean that you can immediately proceed to installing a septic tank. The construction of a structure of this type necessarily requires drawing up a project, which is approved by the local sanitary and epidemiological service. When drawing up a project, specialists must take into account all the features of the site and the nature of the soil in order to accurately determine the required distances to other objects.

Construction must be carried out exactly in accordance with the project - the owner’s “amateur activity” discovered later will be considered a serious administrative offense with all the ensuing consequences.

How much septic tank will be required?

The next determining stage in choosing the required septic tank is determining its volume to ensure maximum purification of sewage, complete decomposition of organic components, and prevent rapid overflow of the tank. At the same time, a reasonable approach to choice must be observed - a septic tank that is too large will cost much more, take up much more space, and its installation will require serious labor costs.

There are several methods for calculating the required capacity of a septic tank, but all take into account the time required for the full process of settling and primary decomposition of organic matter. For example, you can give this rather “heavy” formula:

W– the required volume of septic tank chambers per person;

Q– average wastewater flow, cubic meters per day;

t– time required for treatment and sedimentation of wastewater (days);

WITH– concentration of unsettled suspended matter at the outlet of the septic tank, mg/l;

N– standard indicator of water disposal for each family member, l. per day;

T– average wastewater temperature, °C.

The concentration of suspended matter is taken from the table, based on the average temperature of wastewater and the average water consumption per person per day:

Concentration of unsettled suspended matter at the outlet, mg/l	Average wastewater temperature, °C	Required settling period for wastewater (days) depending on the water disposal rate per person (l./day)
		50	100	150	200	300
50	7	11.1	6.4	4.6	3.5	2.4
	10	10.3	5.8	4	3	2
	15	9.5	5.2	3.5	2.6	1.6
	20	9	4.8	3.2	2.8	1.4
70	7	7.7	4.5	3.2	2.4	—
	10	7.2	4	2.8	2.1	—
	15	6.6	3.6	2.4	1.8	—
	20	6.2	3.3	2.2	1.6	—
100	7	5.2	3	2.1	1.6	—
	10	4.8	2.7	1.9	1.4	—
	15	4.47	2.4	1.6	1.2	—
	20	4.2	2.2	1.5	1.1	—
150	7	3.3	2	—	—	—
	10	3.1	1.7	—	—	—
	15	2.9	1.6	—	—	—
	20	2.7	1.4	—	—	—

The formula looks “intimidating”, it involves raising indicators to complex powers, which requires a special engineering calculator, and it is very doubtful that there will be at least one owner of a private house who will resort to such calculations. But it is quite possible to take a simplified route.

Sanitary standards require that wastewater in a septic tank undergo at least a three-day cleaning cycle. This means that the chambers of the device must contain three times the amount of water consumed by all family members.

W=3×n× Qn

n– number of family members.

Qn– average consumption per person.

There is another formula that is often used to calculate the volume of two-chamber septic tanks, which also takes into account a certain probability of maximum use of the entire planned flow rate by all consumers (this, you see, also does not happen so often).

W = (n × Qn+Qn) × 2

This means that everything is calculated simply if you know the basic value - how much water each person spends per day. But this is already a rather “shaky” value.

It is generally accepted that in average reality daily consumption is 200 liters per person. However, this indicator is not always correct. Consumption may be lower, for example, in houses that are not equipped with bathtubs or showers. And if the house has all the “conveniences”, and in addition to all this, modern household appliances that use water (washing machines, dishwashers) are installed, then consumption will be much higher.

In addition, it is necessary to take into account the likelihood of an increase in the number of consumers, temporary (the arrival of guests or even permanent (family expansion). The septic tank is laid out for many years in advance, that is, a certain reserve, at least 30%, is necessary one way or another. In addition, a reserve is necessary and because during the period between pumpings the capacity of the septic tank gradually decreases due to settled silt deposits.

Below, the reader will be offered a convenient calculator that allows you to quickly and with a sufficient degree of accuracy determine the required volume of the septic tank. It will be necessary to indicate the number of water consumers, and in one of the fields of the initial data request, tick the necessary options - the presence of certain types of plumbing fixtures or household appliances and the approximate mode of their use.

Go to calculations

This calculation is applicable for a septic tank constructed on its own, and for a ready-made one purchased. If planned self-build, then it is necessary to take into account that the calculated volume must be correctly distributed between the chambers. With a single-chamber - everything is simple. In a two-chamber chamber, 75% of the volume should be in the primary chamber, the remaining 25 in the second. In a three-chamber, 50% of the capacity is given to the first chamber, and 25 each to the second and third.

In purchased septic tanks, of course, this ratio is already taken into account by model developers.

The question of the number of cameras is usually approached as follows:

A– a single-chamber septic tank, with subsequent discharge to filtration fields or a drainage well, will be sufficient with a total daily water discharge not exceeding 1 m³.

B– a two-chamber septic tank is usually purchased if the daily volume of wastewater is in the range from 1 to 10 m³.

IN– a three-chamber septic tank is required for large volumes of wastewater, over 10 m³ per day.

This is a recommendation, and in the case of small volumes it is not considered a rule. That is, and not too high level water consumption, you can purchase a compact two- or even three-chamber septic tank, also equipped with a biofilter - such models are commercially available. This will only improve the quality of water purification. In addition, it is quite possible that local requirements of the sanitary-epidemiological or environmental service may directly indicate the mandatory use of septic tanks of one design or another.

Additional criteria for choosing a septic tank

Dimensions of the septic tank and its layout

Of course, the size of the septic tank primarily depends on the required volume of chambers. However, it is often possible to choose from those offered for sale, with approximately the same volume and equal number of cameras, a vertical or horizontal model.

First of all, it is necessary to proceed from the area of ​​the site that can be allocated for installing a septic tank. Naturally, a horizontal septic tank will require more space. But to install a vertical model, you will have to dig a deeper pit.

The depth of winter soil freezing is also taken into account here. It is clear that in order for the septic tank to function year-round, it is necessary to prevent the liquid in it from freezing, that is, place it so that the accumulated wastewater is located below the freezing level (this value is easy to find out at any local construction or hydrometeorological organization).

If the soil freezes to a great depth, then, of course, the best option will be a vertical model. But if the site has a high location of aquifers, then, of course, preference should be given to horizontal ones.

A common problem with bulk septic tanks is “floating”, pushing them upward during seasonal temperature changes. To avoid this phenomenon, it is recommended to install treatment plants on concrete slabs placed underneath and tie them to them with anchor ties. A vertical septic tank wins in this regard - it is more stable due to its smaller cross-sectional area in plan.

When choosing a model, especially a horizontal version, the required height of the inspection necks must be taken into account - when installing a septic tank to a great depth, they must reach the level of the ground surface.

Taking into account soil characteristics on the site

The choice of septic tank is seriously influenced by the nature of the soil on the site.

• For light sandy soils and deep aquifers, the optimal choice would be a septic tank that discharges the water that has undergone initial purification to filtration fields. This is the most economical option.

• If the site has clay soil with low drainage capacity, then most likely you will have to think about purchasing a full-fledged biological or biochemical treatment station. Water that has undergone a full cycle of such post-treatment can already be drained to the surface, for example, into a drainage ditch, or accumulate in a storage tank with periodic pumping to the ground or for household needs.

The cost of such complexes is quite high, and they usually require the installation of additional pumping equipment.

Another option is to independently organize a filter field, but this is a very labor-intensive and expensive option. A large volume of clay soil will have to be demolished and removed and replaced with sand and gravel backfill - an extremely large-scale and expensive job. They resort to this approach only in cases where it is impossible to use a septic tank with biochemical treatment.

• If there is a close location of aquifers on the site, then soil filtration of wastewater without preliminary biochemical treatment is completely excluded.

The septic tank must be completely sealed and have special system valves that prevent groundwater from entering the chambers, equipped with biofilters, pumping equipment for pumping purified water from the well to an irrigation dome or an artificially made surface filtration field. Surely, all these requirements will be presented to the owner of the site when drawing up project documentation.

Material for making a septic tank

Septic tanks on sale can be polymer or metal. Each variety has its own advantages and disadvantages.

• The simplest metal septic tanks are quite different affordable price. Their main advantage is considered to be their large mass - such a tank is less susceptible to “floating” than others. However, the massiveness also creates a number of difficulties associated with transportation, loading and unloading and installation work - in most cases, special equipment will be required.

A metal septic tank must have high-quality waterproofing and anti-corrosion treatment, both outside and inside, otherwise it will not last long under aggressive operating conditions.

Another drawback is that due to the significantly high thermal conductivity of the metal, such septic tanks are at greater risk of freezing, even if they are located below the freezing level of the soil. This means that you will have to consider the issue of their effective thermal insulation, for example, using mineral wool. All this is an additional cost of material resources and time.

However, metal septic tanks are quite widespread, especially among summer residents, apparently due to the simplicity of the design and low price.

• Plastic septic tanks are currently the most popular. They represent a complete structure, usually reinforced with strength ribs, and are relatively light in weight, which greatly facilitates its transportation and independent installation.

1 – septic tanks made of low-density polyethylene (HDPE) – the lightest of all, relatively inexpensive. Cast using virtually seamless technology, in any configuration. which ensures guaranteed tightness of containers. There are restrictions on maximum wastewater temperatures.

2 – cleaning stations made of polypropylene – more resistant to abrasive abrasive loads and accentuated impacts. The density of the material is even slightly lower than that of HDPE. They have excellent resistance to high and low temperatures - they can be used for cleaning hot wastewater.

3 – septic tanks made of fiberglass, the most reliable and reliable among all polymer ones. The manufacturing material has pronounced chemical resistance even to aggressive organic solvents, so such containers can be used for the treatment of industrial wastewater. The price for fiberglass septic tanks is the highest (all other parameters being equal).

All modern plastic septic tanks are designed for many years of operation - up to 50 years or more. Their common disadvantage stems from their advantage - the small mass of the container makes it more likely that it will “float” to the surface, that is, the issue of fixing the septic tank in the ground should be thoroughly considered.

Brief overview of septic tank models

And at the end of the publication - brief overview models of the most popular manufacturers among Russian consumers.

Series "Tank"

These are probably the leaders in popularity due to their low price, simplicity of design and operation, and high rates of wastewater treatment.

Septic tanks have a characteristic ribbed shape to increase structural rigidity, and the thickness of the HDPE walls reaches -10 mm on flat areas, and up to 17 mm on the peaks of the ribs. This guarantees long-term trouble-free operation of the septic tank for at least 50 years.

The range of products includes models designed for both small families (1 ÷ 3 people) and a large number of water consumers (up to 9 ÷ 10). In addition, the modular design allows you to assemble general systems any required performance.

If desired or necessary, a biofilter can be easily built into the septic tank, and it is possible to install pumping equipment.

The minimum volume is 1.2 m³, with a capacity of up to 600 l/day. Moreover, the weight of such a septic tank is only 85 kg, that is, it is not at all necessary to use construction equipment to install it.

Biotank series

“Biotank” septic tanks are a full-fledged autonomous treatment plant, the water from which can be simply discharged to the terrain.

This is a four-chamber design of vertical or horizontal design, with a full cleaning cycle, including aeration and a biochemical filter. Available in various modifications, both with forced pumping of water and with its movement by gravity.

The product range includes models with capacities from 1000 to 3000 liters (from 3 to 10 consumers).

Septic tanks "Triton T"

Inexpensive, simple to install, but at the same time productive and reliable septic tanks of the Triton T series. They are a three-chamber horizontal container made of durable polyethylene, with wall thickness from 14 to 40 mm.

The centrally located neck provides access to all three compartments of the container. The neck can be extended in cylindrical segments with a height of 500 mm. Installation of a special well for the pump is provided.

The model range is from 1 to 40 m³, that is, such a septic tank of the required volume can be used to create a sewerage system for several houses at once.

Cleaning stations "Topas"

Topas septic tanks are complete autonomous sewage systems that carry out deep water purification, after which it can be discharged onto the ground, onto filtration fields, or even into natural flowing reservoirs.

The four chambers of the installation are equipped with all levels of purification - from conventional settling to biochemical filtration. Aeration with complete oxidation of organic matter is provided. It is possible to independently regularly clean the chamber from silt deposits using an airlift or a drainage pump, without resorting to calling a sewage disposal truck.

The product range includes models designed for different numbers of consumers - from 5 to 20 people.

Video: installation of a local treatment plant “Topas”

It is characteristic that all the models discussed above are Russian-made.

It is very difficult to pay attention to all manufacturers on the scale of one publication. Deserving ones can be mentioned positive feedback foreign-made septic tanks “Uponor Bio”, “Alta Bio”, “Fast”, “Evo Stok Bio”, domestic ones “Unilos”, “BIOzon”, “Topol”, “Chistok”. Tver brand septic tanks perform well in everyday use, but, however, their installation should be carried out exclusively by specialists - there are too many nuances in the installation and debugging of equipment.

And one last thing. If a family lives outside the city only sporadically, on weekend visits, then a full-fledged septic tank is most likely not needed, especially since the biocultures in it can die simply due to insufficient nutrient medium. In this case, it would be wiser to install a so-called storage septic tank, or else just a sealed storage tank of the required volume. An example of such a model is the Triton N septic tank, with a capacity of 1000 liters or more.

The process of biological decomposition and sedimentation of wastewater will also take place in such a septic tank. But, of course, we are not talking about any discharge of water into filter fields or drainage wells. You just have to call a sewage disposal truck as the container fills.

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The construction of a suburban building, as you know, requires compliance with a number of norms and requirements. This applies to most of the communications of the house, since the comfort of living of the residents depends on the quality of the design of its individual systems. The treatment system, called a septic tank, was no exception.

There are many rules that determine, for example, how to calculate the volume of a septic tank, as well as various recommendations directly for installing a sewer system. However, one of the main parameters with which owners often have difficulties is the dimensions of the septic tank, since it is not always possible to correctly determine exactly what size the treatment system for a particular structure should have. Therefore, we will discuss how to calculate the volume of a septic tank for a home.

We determine the dimensions and volume of the septic tank

It is important that the calculation of the volume of a septic tank for a private house is subject to the following factors:

1. The average amount of water consumed by one family member.
2. Approximate volume of sewage (as a rule, this figure is within the previously specified water consumption parameter).
3. General values, defining technical condition buildings.
4. Climate conditions in a particular region.
5. Financial component of the work.

When determining the approximate dimensions of a septic tank, it is worth noting that the water consumption parameter can vary significantly: the minimum value is 125 liters, and the maximum is 350. Moreover, these figures depend on whether the building has a hot water supply or not (if it is absent, the value, of course, will be smaller).

The procedure for calculating the volume of a septic tank

Everyone knows the principle of operation of a septic tank, which consists of treating wastewater and disinfecting it, which is achieved thanks to the ongoing fermentation process. However, not everyone may know that a septic tank can be used if the daily water flow rate does not exceed 25 m³/day.

In order for wastewater recycling to proceed faster, it is necessary to achieve maximum speed their fermentation. As a result, reducing the rate of this process significantly slows down sewer cleaning.

The reasons affecting the decrease in fermentation rate include the following:

• excessive filling of the treatment system;
• low temperature precipitation (if it is less than 6 °C, this significantly slows down fermentation);
• too many different chemical compounds included in the composition sewer water.

The last factor is quite significant. Due to the fact that precipitation remains inside the septic tank for at least six months, it is very important to calculate the size of the septic tank for a private house so that its volume corresponds to the amount of wastewater accumulated in it.

One of the parameters that influences the determination of the volume of a septic tank is the time during which liquid waste is contained in it (the standard time is 2 - 3 days). Taking this into account, we can say that if the average wastewater flow rate is 5 m³/day, then the volume running waters can be calculated using a simple formula: 3*Q (Q is the total amount of fluid consumption per day).

To calculate the average volume of precipitation, it is necessary to take into account such parameters as the solid residue of one person per day (approximately 0.8 l); the time required for complete rotting in one day (denoted by “t”); an indicator showing the natural decomposition of sludge in the amount of 30% of its total amount; the volume of sludge remaining since the last cleaning of the system in the amount of 20% of the total volume.

Taking into account all these parameters, you can create a formula that allows you to determine how long the septic tank will definitely fill to the limit: 0.8 * t * (100% - 30% / 100%) * 120% = 0.8 * t * 0, 7 * 1.2 = t * 0.672. In addition, such a calculation of a septic tank for a private house will also answer the question of how often it is necessary to clean the autonomous sewer system.

How to calculate water consumption for a private home

As mentioned earlier, one of the criteria that directly affects how to calculate a septic tank is the parameter of the volume of water consumed by one person during the day. According to many building codes, a value of 150 l/day is taken as the basis for this unit. However, it is important to remember here that this figure only takes into account water consumption for sanitary purposes (toilet and sink), and many other sources of water consumption are not taken into account.

So, in addition to this parameter of 150 liters, it is extremely important to take into account other objects through which a significant part of the water also drains.

These include the following:

• taking a shower for just one minute is equivalent to wasting 10 liters of water, and given that the average time required for one person to fully wash is 7 minutes, it is important not to forget about this source of water consumption;
• another object where water is consumed in large quantities is a jacuzzi (average parameter - 110 l);
• when using washing machine for one wash, approximately 70 liters of water go down the drain;
• one round of work dishwasher requires at least 15 liters of water.

These data will make it possible to more accurately calculate what exactly a septic tank should be so that its volume is sufficient to process the total amount of wastewater in a country house.

What should be the depth of the septic tank and its dimensions?

It is not always the case that the area near the cottage allows for a large wastewater treatment system. However, the solution here is extremely simple: to save space, you just need to make the system deeper, for which you need to correctly calculate the dimensions of the rings for the septic tank.

According to building codes The minimum area of ​​the sewage water tank should be 1.8 m in length and 1 m in width.

If we take a house with four residents as the basis for calculations, then the formula for calculating the depth of the septic tank can be as follows: 4.8 / 1 / 1.8 = 2.6 m. This means that for such a number of people, the septic tank must have a depth of at least 2 .6 m.

In the process of work, you should be guided by the following recommendations from experienced specialists:

• as mentioned above, without sufficient space on the surface of the summer cottage, the septic tank can be extended in depth, taking into account the specific calculations and taking into account the number of people living in the house;
• it is important that the treatment system is located above the groundwater, and not below, otherwise the entry of waste into it will negatively affect the environmental situation on the site;
• For cold areas, one of the prerequisites for installing a septic tank is to install it below the depth to which the soil freezes. Sometimes this value can be quite large (up to two meters).

Taking into account all of the above tips and the correct approach to calculations will allow you to set up a reliable and stably functioning autonomous sewer system. If difficulties arise with its installation, you can always seek help from specialists who have photos of samples of septic tanks for a country house, as well as detailed videos on their installation and operation.

Well, the last article in the topic about calculating the size of a septic tank is about how to calculate the volume of a septic tank.

At the same time, let’s touch on calculating the size of the drainage hole - maybe it will be useful to someone.

And since this is the last article, we will draw final conclusions about the choice of septic tank sizes.

Number of chambers and design of the septic tank

A septic tank is a container with a number of chambers from one to three. The chambers are connected to each other using pipes to allow wastewater to pass from one chamber to another and so on until the outermost filtering chamber:

Water from the outer chamber can go into the soil through pipes or directly through unsealed walls and bottom... although this is not welcome, and these drains need to be further purified, which, however, I already wrote about in the very first article about septic tanks. Then why am I repeating here about the design and what does the size of the septic tank have to do with it, you ask? To refresh your memory, this will be useful to us, starting with the next line...

How to calculate the volume of a septic tank?

The volume of a septic tank does not mean the entire volume of the tank, but only its working volume.

What is the working volume of a septic tank?

Let's look at the diagram (clickable):

The outlet from the septic tank is 3-5 centimeters below the inlet. Therefore, only the working volume of the septic tank is considered - that which can be filled with wastewater, from the outlet level to the bottom.

Calculation of septic tank volume based on the number of drains

Well, now the actual calculation of the volume of the septic tank.

To calculate the volume of a septic tank, you need to take into account the average daily volume of wastewater. Because the water should not just flow through the septic tank without stopping, but must remain inside for some time so that the solid particles have time to settle. In addition, the decomposition processes of these particles also take time. Therefore, wastewater should remain in the septic tank for at least two days. But ideally – up to ten days! I think it’s clear: the longer the wastewater stays inside the septic tank, the better it will be cleaned (settled).

Based on these considerations, we calculate the volume of the septic tank.

In SNiP it is written: “the full design volume of the septic tank should be taken: with a wastewater flow rate of up to 5 m3/day. - at least 3 times the daily inflow, with a flow rate of more than 5 m3/day. - no less than 2.5 times” (clause 6.79.).

Again. Let's say we estimate that the volume of wastewater from our house will be approximately 5 m3 per day. This means that the minimum volume of our septic tank should be 15 m3. More is possible, less is not. When the volume of wastewater is greater than 5 m3, we multiply our “estimated” value by 2.5 and also get a value, less than which the volume of the septic tank should not be made, and more - as much as necessary.

By the way, with such calculations, at least once a year the septic tank will need to be pumped out.

Septic tank volume and number of chambers

Besides what has been said. Septic tanks can be made with one, two or three chambers.

The volume of these chambers is also regulated by SNiP:

“depending on the wastewater flow, the following should be taken:

single-chamber septic tanks - with wastewater flow up to 1 m3/day,

two-chamber - up to 10 m3/day,

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 ones - 0.5 of the calculated volume of wastewater. In this case, the volume of the second and third chambers should be taken as 0.25 of the calculated volume. In septic tanks made of concrete rings, all chambers should be of equal volume.”

In my opinion, everything in SNiP is written quite transparently, there is nothing to comment on.

Calculation of the volume of a septic tank using the formula

Volume of the septic tank = (Number of people living in the house x Rate of water consumption per day per person x Number of days for which the septic tank purifies the water) / 1000

So, the conditions of the problem:

A family of 4 lives in the house,

The daily water consumption per person is 200 l,

The effluent in the septic tank must settle for at least 2 days.

We substitute the data into the formula and calculate:

Septic tank volume = (4 x 200 x 2) / 1000 = 1.6 m3.

Let me remind you: we considered the WORKING VOLUME of the septic tank, and not the total volume of the container.

But don’t rush to grab a shovel and dig, please finish reading the article, there is something else there that needs to be taken into account when calculating the volume of a septic tank. Namely: the volume of the sewer tank.

How to calculate the size of the drain hole?

The depth of the drainage pit can be determined in the same way as the depth of the septic tank. But, since there are no requirements for hydraulics, the shape of the drainage pit no longer matters much (let me remind you that water flows through the septic tank, but in the drainage pit it simply “wait”). Just as the ratio of the length and width of the pit does not matter.

The volume here is also calculated from the average daily water consumption.

You can apply the following formula:

Vpits - volume of the drainage pit,

Ndays is the estimated number of days after which the pit is pumped out (for some reason it is recommended to do this at least twice a month, i.e. every 15 days, I don’t know why, maybe so that the vacuum cleaners don’t get used to working? :)),

Nperson - the number of people permanently residing in the house,

V1 is the estimated volume of water per day per person (it is believed that this is ~150 l).

For example, if a family of 4 permanently lives in a house, then:

Vpits = 15 * 4 * 150 = 9000 liters = 9 m3

The installation of an absorption drain pit allows wastewater to be discharged directly into the soil. This is possible with small (in my opinion, less than one cubic meter) volumes, since it is not capable of causing significant harm to the environment.

Septic tank volume and volume of sewer tanks

In the calculation examples given above, of course, the values ​​are averaged.

It is better to increase the settling time of wastewater in septic tanks.

The volume of the septic tank and drainage pit can be adjusted to the volume of the tank of the sewage disposal machine, which will pump out wastewater. It is not recommended to make a septic tank less than 3 m3 (the tank of a sewage disposal truck has approximately the same volume, a little more: 3.2 cubic meters). If the septic tank is significantly smaller, then it turns out that you are paying for a full car, but in fact it will only take out part of its possible volume.

There are cars with a five-cc tank; if they are in your area, then you can orient the volume of the septic tank to them, check this where you live.

General conclusion about calculating the size of septic tanks

So, in order to determine the dimensions of the septic tank, you need to correlate the following: the required working depth of the septic tank, surface area (length x width), minimum and maximum allowable dimensions, as well as the capabilities of the sewage disposal machine (if, of course, the septic tank will be pumped out with it). And then we move on to the choice of materials; Read about the pros and cons of each material and the technology of construction from them in the following articles.