An important question that faces private developers who are installing a local sewage system on their site is how to calculate the volume of a septic tank. After all, the construction of an insufficient volume, at best, will not provide the necessary level of wastewater treatment, and in the worst is water will stop going into the ground due to the fact that the absorption device will quickly silt up. Too much large capacity- simply overspending. Calculation of the volume of a septic tank is also necessary in the case when, upon receipt of a developer’s passport, it is necessary to justify the construction of a local treatment plant.

Before you start making calculations, you should know how a septic tank works and decide on the type of device. After all, treatment plants are different, often consisting of several communicating tanks (chambers). It is necessary to calculate not only the total capacity, but also the volume of each chamber, taking into account the capabilities of a filter well or other ground treatment device.

A septic tank is a local treatment facility of an incomplete cycle, from which clarified wastewater is discharged into the ground for further treatment. Two processes ensure wastewater treatment in the septic tank itself:

Separation of insoluble particles with their deposition to the bottom of the container and subsequent removal of sludge as it accumulates.
Separation of refractory fats, the decomposition of which takes a long time.
Processing of biological contaminants into mineral sediment by microorganisms living in wastewater. In a septic tank, where the water is practically stagnant and contains very little dissolved oxygen, mainly anaerobic (not requiring oxygen) bacteria live. Their metabolism is slow, so the process of biological wastewater treatment takes a lot of time. In aeration biofilters (aeration tanks), where water is forcibly mixed and saturated with oxygen, the process of processing biological contaminants is much more intense. It is provided by aerobic bacteria that use oxygen during chemical reactions. By the way, a “slow” septic tank can always be turned into a “fast” aeration tank by equipping it with a constantly functioning aerator.

Rational design of a septic tank

The efficiency of a septic tank primarily depends on how rational its design is and whether it corresponds to the specific residential building. Before you calculate the volume of a septic tank, you should decide what elements it should consist of. The treatment facility can be either single-volume (single-chamber) or consist of several sections.

How many chambers should there be in a septic tank?

SP 32.13330.2012 (updated version of the Union SNiP 2.04.03.85) states the following: provided that no more than 1 m3 of wastewater enters the treatment plant per day, the septic tank can have only one section (chamber). If the volume of wastewater is 1-10 m3, it is necessary to divide it into two communicating compartments. And when the amount of daily waste is over 10 m3 - by three. But that's just minimum requirements.

When the daily volume of wastewater is up to 1 m3, the treatment plant is allowed to be made single-chamber, up to 5 m3/day - two-chamber, up to 10 m3 - three-chamber. You can make more compartments, but you can’t make fewer.

We are staunch opponents of single-chamber septic tanks, unless we are talking about a small summer cottage, but about a full-fledged residential building with year-round living. We advocate that, regardless of the volume of wastewater, there should be more than one chamber, optimally three. There are several reasons for this:

In a single-chamber septic tank, new, dirty waste is constantly mixed into wastewater that has already undergone an incomplete treatment process. Thus, in general, the degree of purification of wastewater entering the soil is low, which does not contribute to maintaining a high level of environmental safety on the site.
Domestic wastewater contains insoluble particles and refractory fats, the decomposition time of which is long. In a single-chamber septic tank, they separate, settling to the bottom of a single chamber and, without having time to decompose, are covered from above by subsequent layers. If a septic tank is built in the form of a well and wastewater penetrates into the soil through the bottom, after some time the absorbing surface becomes clogged and the water stops flowing. You have to clean the well, which is very troublesome, or remove the wastewater with a sewer truck, which is expensive.

Cleaning is more effective when various processes(mechanical separation and biological treatment) are clearly divided into stages and occur in different compartments. We believe that optimal quantity there are three chambers for a septic tank in a full-fledged private residential building, and the minimum is two. At the same time, in a three-chamber structure, the third section can simultaneously serve as an absorption device; directly from it, the wastewater will go into the ground for further treatment.

Scheme of a multi-chamber septic tank

We found that if a multi-chamber treatment plant has the same total volume as a single-chamber one, the degree of wastewater treatment in it will be noticeably higher. In a multi-chamber septic tank, kitchen waste and other large undissolved particles are first separated, settling to the bottom of the primary chamber. Refractory fats of animal origin are mainly separated there. The decomposition of organic matter with the help of microorganisms begins already in the first chamber, but is not yet very active. The most intensive decomposition of organic matter occurs in the second section (methane tank), and the most aerbic bacteria live there.

Scheme of a two-chamber septic tank

If there is a third chamber, the wastewater in it is clarified, and cleaning with bacteria continues. Small particles settle, which subsequently, for the most part, also decompose. Between the compartments, the liquid flows through a system of water seals, moving in one direction. Having gone through all the stages of preliminary treatment, the clarified wastewater goes into the ground, where the process is completed by microorganisms living in the soil. The area of water absorption by the soil must correspond to its permeability and discharge volumes. It is also necessary to take into account the groundwater level (GWL). At favorable conditions the third section of the septic tank can simultaneously serve as a filter well, discharging liquid into the ground.

Three-chamber treatment facility with drainage of wastewater for soil treatment from the third section, which acts as an absorption well

At high groundwater levels and low water permeability of soils, additional structures may be required: a filter trench, an infiltrator or a filtration field.

It is important to correctly divide the total volume of the septic tank into separate compartments. Provided that wastewater is supplied daily in approximately equal volumes, the water is kept in the treatment plant for at least two weeks, the most balanced ratio of chamber volumes is considered to be 45%/30%/25%. It is not necessary to strictly adhere to these numbers; it is enough to divide the cameras in a ratio of 2:1:1. In a two-chamber structure, sections can be made of equal volume.

Ready-made factory three-chamber septic tank. You can visually see how much larger the first section of the tank is than the subsequent ones

How to calculate the volume of a septic tank for a home

The “correct” formula for determining the volume of a septic tank for professionals and those who are especially meticulous

Let’s leave the exact calculations to the professionals and use the simplified method ourselves. The answer is something like this: the tank must hold the amount of waste that will come from the house for the time it takes to clean it. But there is a problem with time. The fact is that the building codes indicate that the local treatment plant must be designed for at least a three-day volume of wastewater. And sanitary standards stipulate not time, but minimum permissible level water contamination, which can be sent to the ground for further treatment. The level to which it will be possible to purify wastewater in a septic tank depends on many factors: its design, the degree of initial contamination, season, etc.

But on average, for household wastewater from a residential building, the degree of purification is 65% of the initial level of pollution and the time required for this is two weeks. So after all, 3 days or 14? The difference is almost five times! We recommend focusing on more stringent sanitary standards. On the one hand, it is unlikely that SES representatives will take sewage samples from your septic tank and examine them in the laboratory.

On the other hand, epidemiologists are required to monitor cleaning devices, and at least check them when a house is accepted for use. Why conflict with environmentalists? In addition, you yourself will be calmer, knowing that the environmental situation on the site is favorable.

An example of calculating the capacity of a septic tank

We suggest considering how to calculate the required volume of a septic tank, based on specific example. The joint venture recommends taking 200 liters of sewage per person. In reality, the figure may differ significantly. If you live in a city, look into your “fat”, find the water consumption, divide it by the number of family members and the number of days in the month. Get the real value for today. But in reality, a little depends on the amount of waste. Let's say you install a jacuzzi in your house and equip a swimming pool. The volume of wastewater will increase noticeably, but the degree of pollution will decrease. Accordingly, they can be cleaned to the required level in less time. Greater value has something to do with how you cook food and wash dishes: the more animal fats you use when preparing it, the more waste that goes into the sewer system, the longer it takes for the waste to be processed.

Example calculation for a family of four

So, let's go back to the figure of 200 l/person. Let's say we need to build a local treatment plant for a family of four. For four people this will be 800 liters per day. We count according to the norms:

By building regulations: 800l/day x 3 days = 2.4 m3. This is a regulatory minimum, but practice shows that when permanent residence there are not enough people.
According to environmental rules, approximately: 800 l/day x 14 days = 11.2 m3. This is too much, the septic tank will be large and, therefore, not cheap. Is it possible to save money? Yes, sure. First, you need to reduce the load on the treatment plant. We will not reduce the amount of feces, and besides, they are by no means the most difficult to process. On the contrary, for bacteria this is the most favorite food; microorganisms will deal with delicacies first. It is more important not to pour refractory fats of animal origin into the sewer in large quantities; send vegetable waste into compost and not into pipes. You should also minimize the use of chlorine-containing detergents in your home, which harm the beneficial microflora of the treatment plant. By reducing the pollution of wastewater, it is possible to reduce the estimated volume of daily discharge. Let's say, up to 120 l/person - 480 liters for four per day.

We get 400 l/day x 14 = 6.72 m3. With properly organized life, a seven cubic meter septic tank is quite enough for a family with two children. The first chamber is approximately 3.5 m3, the second and third are 1.75 m3 each.

Whatever figure you come up with according to your calculations, we do not recommend making a treatment facility of a smaller volume than a sewage disposal truck can remove. After all, even in a properly functioning device, insoluble sediment accumulates, which will have to be removed once a year. The capacity of the most common machines for pumping and removing sewage is from 3.8 to 5 m3.

An example of calculating a treatment plant using standard elements

Most septic tanks are quite justifiably built from factory ones. reinforced concrete elements. Let's look at how to calculate the volume of a septic tank from concrete rings.

The internal volume of a standard meter ring is 0.7 m3; one and a half meters - 1.57 m3 and two meters - 2.8 m3. We will assume that the input sewage pipe and the flows between the chambers are not located under the lid itself and the wells can be filled no more than 80%.

In order to provide 6.72 m3 for waste, as in the previous example, we need to have a total internal volume of 6.72: 0.8 = 8.4 m3.

Now let’s “scatter” these 8.4 m3 among the elements:

Two-chamber structure: two sections of 4.2 m2 each. You can collect them from three “one and a half” each. The volume of one chamber will be 4.71 m3, both - 9.42 m3. Approximate useful volume 9.42 m3 x 0.8 = 7.5 m3.
Three-chamber septic tank. The first chamber is the same as in the two-volume one: three rings of 1.5 m each. The second and third can be made from three meter elements each. The internal volume of one is 2.1 m3. Overall volume 4.71 + 2.1 + 2.1 = 8.91 m3. At 80% filling, the useful volume is 7.1 m3.

You can assemble a three-chamber septic tank from rings of larger diameter. For example, the first section of two 2-meter ones, the second and third of two 1.5-meter sections each. The total capacity will be 11.88 m3, useful - 9.5 m3.

One of possible options execution of a two-chamber septic tank made of standard reinforced concrete rings

How to calculate the volume of a storage tank and aeration biofilter

In addition to septic tanks, as structures local sewerage Other devices are also used:

Sealed container, from which wastewater is removed by a sewage disposal truck. The minimum volume is determined based on a three-day drainage, in our case it is 4 people x 200 l x 3 days = 2.4 m3. But in order not to call a sewage disposal truck every three days and not to pay for a half-empty trip of expensive special equipment, we recommend 6-8 m3 or more.
An aeration biofilter (aeration tank) is an “advanced” version of a septic tank; the wastewater in it is forcibly saturated with oxygen, due to which the oxidation of organic matter occurs many times faster. On average it takes three days to reach the required level. Accordingly, 2.4 m3 is enough.

We hope that after studying the article you received general idea on how to calculate the volume of a septic tank. But there is still a lot left beyond the scope of the material important issues, in particular, the disposal of wastewater for ground treatment. In order not to “miss” the construction of a septic tank, we recommend consulting with specialists at the design stage.

In practice, there are special building codes. They are used to carry out all calculations of the septic tank, including its volume. The data was approved back in 1986. Despite this age, the norms are still relevant today. Construction is carried out on them new system, and also reconstruct the old sewer system.

General guidelines for calculating the volume of a septic tank

When designing a sewer system, the following must be taken into account:

Average water consumption per day per family member;
Size of wastewater (an approximate indicator of water consumption);
Assessment of sanitary and technical standards of the house, as well as the climate of the area;
Justification of the work by economic indicators.

The fact is that water consumption standards 25 years ago and today differ significantly. According to SNiP 2.04. 09-85 water consumption per person - 125 liters per day - without hot water supply in a house without a bath. The maximum water consumption is close to 350 liters. This is for homes with hot water heating and a bath. These requirements do not include a washbasin, dishwasher or washing machine. It's about about meeting the minimum human needs per day.

Helpful information ! When the volume of a septic tank is determined, it is taken into account maximum amount water consumed by all family members per day.

Examples of calculating the volume of a septic tank in modern conditions

Septic tanks are designed for approximately 25 cubic meters water per day. It is known that one cube contains 1000 liters of water. At mechanical cleaning water remains a raw sediment. He has organic matter. Sediments undergo disinfection through fermentation processes. The fermentation rate directly depends on the temperature in the septic tank.

The rate of fermentation and decrease in septic tank activity is possible for a number of reasons:

The septic tank is overloaded;
Precipitation temperature below 6 degrees, which is unacceptable;
The effluent contains aggressive chemical components.

For at least 6 months, the residue that falls out remains in the septic tank. Therefore, it is necessary to provide the required volume of the septic tank in advance. According to Yakovlev’s method, the volume of a sewerage tank is determined by calculating running and silt water. The sludge part is the sediment that lies at the bottom of the tank.

The volume of the flow part depends on how intensively waste is drained into the septic tank. The liquid drain remains in the tank for up to three days. The flow part with a wastewater flow rate of up to 5000 liters per day will be: 3Q. Q is the total water consumption per day.

The amount of precipitation can be determined by the consumption of solid sediment in the septic tank, which is calculated per person. It is 0.8 liters per day. The calculation is also carried out based on the rate of decay of sediments. Natural decay is taken into account, which is 30 percent per day. After cleaning the septic tank, it is recommended to leave up to 20 percent of the sediment at the bottom.

So: 0.8 * t* (100% - 30% / 100%) * 120% = 0.8 * t * 0.7 * 1.2 = t * 0.672

Using this formula, you can determine how long it will take for the septic tank to fill with organic waste. This means you can know when to start cleaning the tank. The sludge can take from 6 to 12 months to rot. There are more. As time increases, it is necessary to increase the volume of the septic tank.

Calculation of total water consumption per person per day

It is approximately believed that 150 liters of water are needed per person per day. In fact, this information outdated. This indicator does not take into account the operation of the shower, washbasin and washing machine, as well as other devices that are in the house and connected with water.

But for the calculation, let’s take 150 liters of water per day per person. Let's add to this calculation:

1 minute in the shower is 10 liters of water. On average, a shower takes 7 minutes.
The bidet consumes up to 8 liters per minute. On average, a bidet is used for 5 minutes.
One bath takes 110 liters of water.
For 2 kilograms of laundry washing machine you need 70 liters of water.
For one cycle of work dishwasher 15 liters of water are wasted.
The first three points must be calculated per person.

(150 + 10 * 7 + 8 * 5 + 110) = 370 liters per day.

This figure is very close to the maximum water consumption per day. Now you need to determine the water consumption for all family members per day. Only now let’s add the consumption of the washing machine and dishwasher. For example, 4 people live in a house, then:

Q = 370 * 4 + 70 + 15 = 1565 = 1.6 cubic meters per day

This is approximately 1.6 cubic meters of water per day. For a family with 3 people, the following volume of septic tank is required:

3 * 1.6 = 4.8 m3

This is the most optimal size reservoir.

According to SNiP calculations, when using a septic tank with a calculation of 150 liters of water per day and at an average winter temperature of 10 degrees, 20 percent can be added when calculating the total volume of the septic tank. In this case:

4.8 * (1-0.2) = 3.84 m3.

This is the most small size septic tank that can be used.

If the septic tank will be installed at the dacha or country house where they come only once a season, then you can safely reduce the volume of the septic tank by 30 percent.

Calculation of installation of multi-chamber septic tanks

In order to increase the productivity of the septic tank, it is recommended to divide it into two chambers. If you use a septic tank when consuming 5 cubic meters of water per day, then it will be enough with one chamber. If more than 5 cubic meters of water are consumed, then it is advisable to install a three-chamber tank.

If the septic tank has two chambers, then the volume of the first chamber should be 75 percent of the total volume of the septic tank. The second septic tank should be 50% of the total volume.

Important! For a three-chamber septic tank, the volume of the first tank should be about 50 percent. The second and third tanks each use 25 percent of the total volume.

To ensure that installation of the tank does not take much time and effort, you can deviate slightly from the specified values.

Calculation of tank depth

On the site it is necessary to allocate as much as possible less space for a septic tank. According to the requirements, the surface area of the tank must be 1.8 square meters. This means that the minimum width is 1 meter, length is 1.8 meters.

Using the above example, we will calculate the height of the septic tank for use by a family with 4 members. If the volume of the septic tank is 4.8 cubic meters. meters, then:

4.8/1/1.8 = 2.6 meters.

But there are several nuances when calculating the depth of a septic tank.

If the area for a septic tank is limited, then it can be increased by increasing the depth.
The septic tank should not be located deeper than groundwater.
It is best for the septic tank to be located below the freezing level of the soil. In our country, in some regions this level is about two meters.

It is necessary to wisely use the working volume of the septic tank on your site. If you increase or decrease the volume of the septic tank due to incorrect calculation, the functionality of the device will be impaired. It is recommended to perform a separate calculation for each case, rather than being guided by generally accepted standards.

Helpful information! In order to ensure the normal functioning of the sewerage system, it is necessary to take a responsible approach to the calculation of the septic tank, because it is one of the main parts of the entire system. It is important to study all the rules for calculating tank volume. Otherwise, the septic tank may overflow and waste will flow into personal plot. This will lead to pollution environment and an unpleasant odor.

Today, you can turn to professionals for help, who, before installing a septic tank on your site, will carry out preliminary calculations, which there is no point in doubting. This is the only way to forget about what sewage is. However, if there is confidence in own strength, then you can carry out all the calculations and installation of equipment yourself. This way you can significantly save money on calling a specialist and get good experience works

Lately become popular septic tanks, which are already in finished form sold in construction hypermarkets. They have a specific volume. That is, in order to install one of them in your yard, you only need to know how much water will be consumed in the house per day on average.

All other calculations have long been carried out by specialists, taking into account many factors that can influence the septic tank from the environment. However, the price of such products can be quite high. Therefore, it is necessary to calculate all the pros and cons when purchasing.

Septic tank selection calculator.

Septic tank selection calculator- a useful function for everyone who is going to install autonomous system waste water treatment on site summer cottage or in a private home. To choose the right device, you need to take into account several parameters: from the number of people living in the building to the type of soil. Using a calculator, you don’t have to carry out long calculations, but enter the necessary parameters and wait for the results to be generated.

Septic tank selection calculator

Main parameters:

Number of residents

Pipe depth

Discharging water from a septic tank

Accommodation

Soil type

High ground level. water

Plumbing:

0 1 2 3 4 5

Pick up

How to use the septic tank selection calculator?

Septic tank selection calculator will prompt the user:

Enter the number of residents in the serviced area;

Select the type of residence - permanent, seasonal or weekend;

Indicate the depth of the pipe in centimeters;

Decide on the type of soil in which the pipe will lie;

Choose where the water from the septic tank will be discharged: onto the ground, into a well/ditch;

Indicate if observed high level groundwater.

Once this data has been entered, you will need to indicate the quantity sanitary products and household appliances that will be used in the house on on a regular basis. These include:

Toilets;

Bidet;

Shower;

Bath;

Sink;

Jacuzzi;

Washing machine;

Dishwasher.

The required number must be placed next to each product/device. After this, all you have to do is click on the “Select” button and wait until the system selects the systems that are suitable for a particular case. As a rule, it will take no more than a few seconds to generate results.

The system will calculate the average volume of water consumption per day, and also indicate the maximum volume of one-time liquid discharge. Below we will present models that are optimally suited for the specified parameters. To ensure that the calculation results are as close to reality as possible, it is recommended to select the most accurate parameters. Therefore, it would be useful before activating septic tank selection calculator, take an interest in the characteristics of the soil and decide in advance where the treated water will go.

Why do you need accurate calculations using a septic tank selection calculator?

Autonomous wastewater treatment plants can greatly facilitate living in a country house or on a summer cottage, where for some reason it is impossible to connect to central sewer. A septic tank will allow you to process used water and drain it onto the ground without harming the environment, or reuse the liquid for household needs.

With help autonomous sewerage You can significantly increase the comfort of using plumbing and household appliances and not have to think about how to get rid of waste water and where to get water for irrigation - just organize a channel where the waste liquid will be drained. However, there is one “but”.

For optimal selection It will be necessary to carry out complex calculations that take into account all the parameters listed above. It will be difficult for beginners in this matter to cope with such a task, and an error in the calculations can lead to the fact that the wrong septic tank will be selected. This is fraught with consequences.

If the performance of the cleaning system is too low for specific house, the number of residents and the number of household appliances and plumbing fixtures, this will lead to the fact that you will have to limit yourself in the use of water. Such an exit brings certain inconvenience to everyone who lives in the house.

High productivity where there is no need for it will also not lead to anything good. Of course, you won’t have to skimp on washing and bathing. However, we must remember: the higher the performance of the septic tank, the higher its cost. If you choose a cleaning system that, for example, can serve ten people, but in fact three people live in the house, it turns out that users are throwing money away.

In addition, it should be remembered that septic tank selection calculator takes into account not only the number of residents and the number of household appliances and plumbing fixtures, but also the type of residence, as well as the type of soil and the possible level of pipes. After all the necessary parameters are included in a special table, he selects the most optimal options for all specified characteristics. Therefore, in order not to delve into various technical issues, not to waste time, and not to worry about potential errors, you should use the possibility of automatic calculation with the selection of the most suitable devices.

Advantages of using a septic tank selection calculator.

Besides septic tank selection calculator, you can also use the services of relevant organizations that will carry out all necessary calculations, will take into account the homeowner’s wishes and tell him what parameters he should rely on when choosing a system, as well as which models he should pay attention to. Specialists will ask for the same parameters as the calculator, after which, after a certain period of time, they will give the calculation results. Of course, not for free.

Septic tank selection calculator, presented on the website of the Stroy Project organization, will do the same. However, this will take much less time, and all calculations using this function are carried out free of charge. The calculator does not have to go to the site to evaluate everything with his own eyes. In this case, you can observe significant savings in time and Money customer.

You can use the calculator at any time of the day or night, since the website of the Stroy Project organization is freely accessible around the clock. And, after the user has received the calculation results, he can familiarize himself with the proposed models, their characteristics, parameters and technical features. After studying all the proposed options, all that remains is to make your choice, or seek help from the company’s employees who will help him make the right choice.

Most owners of suburban buildings know that septic tanks used for collecting and partially disposing of household waste can have the most various designs. They can be mounted either from reinforced concrete rings standard size, and from plastic containers various capacities. In this case, the most common option is a 2- or 3-section septic tank made of reinforced concrete rings. Special attention when choosing a septic tank configuration, you should pay attention to the fact that the efficiency of such a treatment plant largely depends on its volume, therefore it is very important to correctly calculate the septic tank for a private home, regardless of the chosen septic tank option and the shape of its constituent containers. When choosing this indicator, you should focus on the useful volume, which is calculated based on triple the water consumption per person permanently residing in the dwelling.

Taking into account that the average water consumption per person is about 200 liters per day, the total consumption is determined by multiplying it by the number of residents (see Appendix).

Application:

Number of people	Wastewater consumption, m 3 /day	Septic tank volume, m 3
3	0,6	1,5
4	0,8	1,9
5	1,0	2,4
6	1,2	2,9
7	1,4	3,4
8	1,6	3,9
9	1,8	4,4
10	2,0	4,8

Full payment

The final or full calculation of the septic tank, carried out in accordance with current technical standards, involves a comprehensive consideration of the current factors that manifest themselves in specific operational situations (as opposed to tentative definition its volume according to the table. As a rule, the following factors are subject to comprehensive consideration:

deviation of the average water flow rate in one direction or another;
Availability free spaces under a septic tank of the required volume.

When considering the first of these factors, it should be noted that the above table is used only to approximately determine the volume of the tanks of the future treatment plant. Depending on specific conditions, this value may deviate both towards larger and smaller values. To take into account such deviations, a special correction factor, which corrects the statistical average by simply multiplying by it.

When using water metering devices, in particular, you will need to introduce a correction for its consumption mass, which, accordingly, will reduce the waste volume indicator. IN similar situations a so-called reduction factor of the order of 0.6–0.8 is introduced. For those who like to take refreshing showers and baths every day, on the contrary, you will need to enter an increasing coefficient of 1.5-2. The presence of a water reservoir in a country house leads to the same result. household appliances(washing machine or dishwasher, for example).

Taking into account the average daily water consumption by one user, as well as an additional adjustment for unforeseen expenses (another 200 liters), the size of the settling tanks increases noticeably not only in volume, but also in the area occupied by the entire treatment facility. With a significant increase in water consumption (up to 5 m3 per day), you will need to use a local treatment facility, consisting of two or three chambers that provide accelerated wastewater processing.

Accounting for occupied space

In the case of a limited plot of land allocated for placement treatment plant, you, one way or another, will have to solve the issue of optimizing its linear dimensions (or rather, the usable area it occupies).

For this purpose, with a fixed volume of it linear dimensions can vary in any way. So it can be used as a settling tank concrete pipe with a diameter of 1–1.5 meters, dug vertically into the ground. The depth of immersion of such a pipe into the ground can reach 2.5 m.

Depending on the shape of the sump used, its volume can be calculated using standard formulas.

As an example, let’s look at calculating the volume for a family of 4 people permanently living in a suburban building:

Taking into account the average daily water consumption per person, as well as the data in the table given in the appendix, a family of 4 people will need a sump tank with a total volume of at least 2 m3.
To place such a tank, you will have to prepare a pit with an area of 2 m² and a depth of one meter.
In the event that you do not have the specified area, you can allocate 1 m² of area for the sump, in which a two-meter deep pit is dug.

As the required volume of the septic tank increases, the size of the prepared recess increases accordingly.

Video

More detailed information You can get information about the design, operation of a septic tank and calculation of its volume by watching the video below:

Owners summer cottages And country houses, try to provide themselves with the maximum comfortable conditions accommodation. For these purposes, houses are equipped with all the necessary network engineering including sewerage.

Considering that in most cases, connecting the wastewater system country house To centralized network sewerage is not possible, the site organizes its own wastewater disposal system in the form of a factory-made septic tank, or one built with one’s own hands.

Regardless of what type of septic tank is intended to be used, before its manufacture it is necessary to make a competent calculation of its useful volume necessary for the disposal of wastewater from a particular house. To do this, you need to know how to calculate the volume of a septic tank.

What is the basis for calculating the volume of a septic tank?

This article will outline detailed instructions, which will help calculate the minimum acceptable useful . As an example, we will present the calculation of the volume of a septic tank made of concrete rings for a small family.

What you need to know to calculate the volume of a septic tank

The most common option for a septic tank is a two- or three-chamber treatment system. It consists of two or three reinforced concrete or plastic containers, connected in series with each other using sewer pipes.

As wastewater enters the septic tank, it is cleared of mechanical impurities in the first container and slowly flows into the second container, in which the remaining part of the impurities precipitates and biological treatment of wastewater occurs.

Bacteria in water process organic substances that contain wastewater. After this, purified water is formed, which is supplied for further purification to the third container, and from there, pure water enters the soil or is used to water plants. In the case of a two-chamber system, water from the second tank is supplied to the filtration fields for soil purification.

According to water treatment technology, for proper functioning purification system, it must contain at one time the amount of water that will be consumed in the house within three days.

Technology for calculating the minimum required volume of a septic tank

The basic basis for calculating the volume of a septic tank is the total volume of wastewater produced by all people living in the house in one day. According to statistical data, it is conventionally accepted to consider the average daily water consumption at the rate of 200 liters. for one person.

Accordingly, to calculate it is necessary to multiply 200 liters by the number of people living in the house. You can determine the approximate value of the required volume of a home treatment plant using the table below.

Volume calculation table for a two or three-chamber wastewater treatment system.

However, the data given in the table is indicative only. The actual value may vary within small limits, both up and down, and depend on many factors.

For example, the presence of a bath or sauna in the house, as well as household appliances that consume a large number of water, for example, from a washing machine or dishwasher, can cause a significant increase in water consumption, and accordingly, an increase in the volume of domestic wastewater.

Advice! If the water supply is connected to centralized system water supply, installing a water consumption meter (in other words, a water meter) will not only help you maintain more economical water consumption, but will also help reduce the load on the treatment system.

An example of calculating the volume of a septic tank

As an example, we suggest considering the calculation of the volume for a family of 4 people who permanently live in a country house.

Based on simple calculations, it can be calculated that the total daily volume of wastewater is 0.8 m³. (0.2 m³ X 4 people = 0.8 m³)
Taking into account the need to settle wastewater for three days, we obtain the value of the minimum total volume of the septic tank equal to 2.4 m³. (0.8 m³ X 3 days = 2.4 m³)
If a two-chamber treatment facility is planned to be made from standard concrete rings KS 15-9, we take it for calculation inner diameter 1 m, useful height 0.7 m, we get useful volume = 1.64 m³. Accordingly, two chambers will give a total volume of 3.28 m³.
From here we see that the value of the total volume of the septic tank is greater than the minimum allowable, and still provides some reserve that allows you to increase the daily volume of wastewater without overloading the treatment system.

Note! When calculating the useful volume of a concrete ring, one should take into account not the full height of the ring, but the useful height that the wastewater reaches before it overflows into the next chamber, that is, the height from the base of the ring to the lower edge of the overflow pipe.

Conclusion

As can be seen from the article, for proper organization To make a home-made treatment plant on your site, you need to carry out very simple calculations and follow the rules and recommendations for arranging septic tanks. The price of concrete rings allows even families with a relatively low level of income to install such a treatment system on their summer cottage ().

In the video presented in this article you will find Additional information on this topic.