How much will it cost to build a turnkey septic tank from concrete rings?

How does a septic tank work?

For a small private house, a septic tank made of concrete rings is installed according to the classic scheme, including two tanks. If a significant volume of wastewater is expected, three tanks (wells) are installed, different in design and functionality. The first two wells are made hermetically sealed; in the third, a crushed stone filter is installed, through which the water flows into the soil.

The principle of constructing a septic tank made of concrete rings Source admiral-oz.ru

Purpose and design of cameras

• The first septic well serves to receive and settle wastewater. Here, thanks to the work of anaerobic bacteria, sedimentation occurs and partial treatment of wastewater occurs (Anaerobic bacteria are able to decompose complex organic matter into simple substances without access to oxygen). The initially clarified water flows into the second section. The volume of the chamber should be equal to half of the total planned volume of the system; its base is concreted.
• In the second well (drainage) with sealed walls and bottom, additional filtration occurs. Additional filters made of gravel can be installed here.
• In the third well, final filtration occurs. The bottom here is not concreted; a sand-crushed stone (or sand) mixture is poured in for final filtration.

Calculation of septic tank volume

When installing a septic tank, it is important to first calculate the required volume. Correct calculation will eliminate the need to frequently call a sewer truck and clean the tank.

The minimum capacity of a sewer well is the volume of waste liquids coming from the house for 3 days. As a rule, for calculations it is assumed that each resident consumes approximately 200 liters per day (this is 0.2 cubic meters).

To obtain the approximate capacity, you will need to multiply the number of residents of the building by 2 and 0.2. When operating a multi-chamber structure made of concrete rings, it should be remembered that the resulting value will be equal to the required capacity of the first 2 tanks of the system. The last drainage chamber should not take part in the count.

It is advisable to conduct a soil assessment before building a septic tank with your own hands from rings. This is done to test the soil's ability to accept liquid under a bed of gravel and sand.

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Based on the results of the geological examination, the appropriate volume of the third chamber is calculated, in which wastewater enters the soil. However, this stage is often abused due to reluctance to spend money on the assessment, so in most cases the volume of the third tank is equal to the capacity of the first.

After calculating the required volume, you need to select the appropriate dimensions of the concrete rings and begin installing the septic tank yourself. As a rule, the internal diameter is from 70-250 cm, and the length is from 0.5 to 1 m.

To calculate the capacity of a reinforced concrete ring, you will need to use the formula for calculating cylindrical volume. Then, to determine the quantity, it remains to divide the total capacity by the volume of 1 ring.

The most common product dimensions for installing a septic tank are shown in the image below.

Advantages and disadvantages of a septic tank made of concrete rings

Due to the features of use, design and installation, such a system is the optimal solution in many cases.

Let's consider all the pros and cons of septic tanks made of concrete rings:

Its advantages include:

• simple installation and use technology. There is no need to supply electrical power, arrange additional drainage, or install a pump;
• reliable autonomous design with high mechanical strength;
• complete freedom in choosing the dimensions of the structure;
• long service life;
• large useful volume and easy maintenance;
• resistance to aggressive wastewater environment;
• the weight of the rings is a guarantee that groundwater will not displace the septic tank from the soil;
• available materials and reasonable price for building a septic tank.

Practical application of calculations

The presented method for calculating the volume of a small treatment plant allows you to design a fully functional septic tank on your own or make preparatory estimates for the purchase of a ready-made installation. The method is obviously simple, as well as sufficiently accurate to meet the needs of domestic consumption.

At the same time, it is up to you to decide which method of waste disposal you prefer. On the one hand, a septic tank designed to be assembled from concrete rings will require additional installation efforts and time spent on its construction. However, its relatively low cost will allow you to create wells with a good performance margin. On the other hand, ready-made factory containers guarantee simplified installation and accelerated commissioning of the structure, but for this you will have to pay a significantly larger amount of money than for concrete rings.

Video description

Additionally, the septic tank can be improved - example in the video:

Disadvantages of concrete septic tanks:

• Weight of building material. During installation it is difficult to do without construction equipment.
• The need for high-quality sealing of seams between rings and joints with pipes.
• Hygroscopicity of concrete, which does not allow the method to be used in flooded areas.
• The need for regular cleaning of containers and pumping out wastewater.

Making the right calculations: capacity and design

At the design stage, a septic tank diagram is created from concrete rings, then the volume of the future device is determined:

Number of cameras

The number of cameras depends on the number of people using the sewer system. If a family actively uses the shower, bathtub, and appliances, the drain down the drain will be significant. The drains will require thorough cleaning, for which you will need a septic tank of three wells, two of which will be settling chambers.

Diagram of a septic tank made of concrete rings Source tolkobeton.ru

Capacity

To determine the volume of wastewater entering the septic tank from the kitchen, bathhouse and toilet, you need to calculate the daily water consumption. Knowing that the daily rate of domestic water consumption for one resident is equal to 200 liters, it is easy to calculate that a family of 4 people will fill the septic tank at a rate of 800 liters per day.

The quality of the septic tank improves if wastewater lingers in the chambers for a long enough time. By increasing the volume, you can improve the quality of the wastewater and protect the system from clogging with difficult-to-decompose fat.

According to building codes, the installation must accommodate wastewater that is generated over three days (the daily flow rate must be multiplied by 3). This number determines the volume of the septic tank and the number of chambers:

• a single-chamber septic tank is installed if daily waste does not exceed 1 cubic meter;
• two-chamber – up to 5 cubic meters;
• three-chamber – 8 or more cubic meters.

In a septic tank with two chambers, the first sump occupies the volume of 2/3 of the entire septic tank, in a three-chamber septic tank - half.

Repair and modernization

Septic tanks made of reinforced concrete rings are durable structures, so they do not require repairs. But only on condition that the installation of the septic tank with overflow was carried out without errors. If the installation is not carried out professionally, then repairs may be required very quickly. Moreover, it is unlikely that you will be able to carry out repairs on your own. Most often, it is easier to build a new septic tank than to repair a broken installation.

Much more often than repairs, a septic tank made of concrete rings is modernized. This modification consists of installing an aerator in the second compartment. An aerator is a plastic pipe with numerous holes. Air is supplied to the installation through the aerator; to carry out this process, the aerator is connected by a hose to the compressor.

An aerator is installed to improve the quality of cleaning. The installation in which the aerator is installed provides high quality cleaning. Therefore, it makes sense to modernize and install an aerator if it is not possible to organize water purification.

Advice! It should be noted that the septic tank in which the aerator is installed is an energy-dependent and more complex structure, so repairs to this installation will be required more often.

So, if you want to build an inexpensive but efficient treatment plant for the local sewage system of a private house, which does not require frequent repairs, you should choose a septic tank made of concrete rings - reviews of the use of this installation allow you to count on a long and efficient service, and construction (subject to the use special equipment) will not require much time and effort.

Video description

About septic tanks on high groundwater in the video:

See also: Catalog of companies that specialize in utilities: water supply, sewerage, heating.

Increased structural strength:

• To protect the building from possible ground movements and shifting of the rings, they are additionally secured with metal ties.
• To reduce the subsidence of the septic tank and improve its thermal insulation and drainage, during installation a cushion of sand, crushed stone or gravel is placed around it.

How much will the rings cost?

Concrete rings are selected based on calculations of the volume of the septic tank. The dimensions of concrete rings for a septic tank are indicated on the marking. They are characterized by the height, diameter and thickness of the walls of the structure, as well as the type of product:

• KS – wall ring, suitable for erecting walls;
• PP – floor slabs;
• PD – road slabs, installed at the bottom of the pit.

The cost of concrete rings is affected by their size and location of production. Reinforced concrete rings with low surface permeability, resistant to aggressive environments, are suitable for sewerage.

The height can be 290, 590, 800, 900 mm. A typical product with a height of 900 mm can have a diameter of 700, 800, 1000, 1500 and 2000 mm. The average price for it varies from 1200 to 1800 rubles. Rings with other parameters can cost from 680-1050 to 1500-2400 rubles.

Rings for septic tank Source humphrey.alpvd.ru

It should be remembered that some rings are marked with an internal (useful) diameter, while others have an external diameter, which is important for selecting caps. The average cost of a reinforced concrete cover or polymer hatch ranges from 1,700 to 2,000 rubles.

When drawing up an estimate for a septic tank made of concrete rings, the price takes into account additional materials: pipes, cement, sealant, as well as the cost of work (digging, installation of rings). The final average price of a turnkey septic tank is in the range from 38,000 to 69,000 rubles.

Concrete rings for sewerage

When manufacturing concrete sewer rings, they are guided by sections of GOST 8020-90, which regulate the technical conditions for this type of product. Its main provisions include the following points useful for specialists and ordinary consumers:

1. The structures are made from heavy concrete in accordance with GOST-26633 with a compressive strength of 70% of its grade or class.
2. For reinforcement, rod reinforcing wire, thermomechanically hardened or hot-rolled steel are used.
3. Well rings must comply with the requirements of GOST 13015-2012, which regulate their parameters according to the following indicators:

• rigidity, strength and crack resistance of structures without load;
• physical strength of concrete in its original finished form, and tempering strength after manufacturing the product;
• waterproof and frost-resistant;
• thickness of the concrete layer to the built-in reinforcement;
• grades of steel for fittings, running and loop fillings.

Rice. 4 Concrete rings for sewerage - dimensions according to GOST 8020-90

Concrete rings and auxiliary structures have symbols consisting of the following sequence of alphabetic and numeric symbols with the explanation below:

1. – indication of the serial number of the standard size (1, 2, 3 and so on), quite often the first digit is missing in the designation;

2. – type of reinforced concrete structure:

• KS - a wall ring of a chamber or the neck of a structure, if a narrow manhole of some height with a hatch is installed to access the working chamber;
• KO - support ring, installed on the top plate of the structure to construct a neck under the hatch, through which access to the inside of the working chamber is provided. Differs from the wall type in its low height, larger wall thickness and fixed diameter;
• PN – bottom plate, placed under the well bottom;
• PP – floor slab, installed on top of the structure, has a rectangular or round cutout for mounting a manhole with a hatch;

3. figure: for KO and KS - the internal diameter in decimeters, in the designations PN and PP - the internal diameter of the well rings on (under) which they are placed;

4. – the digital symbol after the dot indicates the height of the wall reinforced concrete products in decimeters.

Rice. 5 Parameters of support rings KO and plates PO, PN according to GOST 8020-90

Video description

The work procedure and installation of a septic tank made of concrete rings in the video:

How to choose the optimal location for a septic tank

The structure is mounted above the groundwater level. The best location is at the maximum distance from the house (at least 7 meters, but no more than 20, so as not to increase the cost of pipeline construction). It is logical to place the septic tank on the border of the site, next to the road. This will reduce operating costs, since the cost of leaving a sewage tank is affected by access to the system and the length of the hose. In addition, with the correct location, the sewage disposal truck does not need to enter the yard, and the hoses will not lie on the beds or paths (otherwise, when the hose is rolled up, waste may end up in the garden).

The distance to the nearest source of drinking water (well, borehole) is at least 30 (and if possible more) meters.

Pit preparation

Ground work using an excavator takes 2-3 hours. The size of the pit should be slightly larger than the dimensions of the wells. This is necessary for the smooth installation of the rings and their waterproofing. The bottom is covered with crushed stone and concreted.

Preparing a pit for a septic tank made of concrete rings Source rostovgruz.ru

What materials and tools will be needed

When selecting concrete rings for a septic tank, it is advisable to pay attention to options with locks. Such rings significantly simplify the installation process and also prevent displacement when freezing and increasing the volume of soil. When purchasing, it is advisable to check that the seats are level and also make sure that the locks are intact.

The following tools and materials are required for installation:

• pipes for sewerage construction;
• standard construction tool kit;
• sand (preferably river);
• building level;
• cement;
• materials for waterproofing a septic tank made of concrete rings with your own hands;
• polyurethane foam;
• perforator;
• ladder;
• large container for mixing the solution;
• large brush.

Overflows between tanks are constructed from special sewer pipes made of polypropylene or asbestos. When purchasing them, it is advisable to make sure that they are suitable for external sewerage.

It is also a good idea to learn what the advantages and disadvantages of different pipe materials are. For example, products made from polypropylene are durable, reliable and elastic. The diameter of the constructed pipeline is approximately 110-120 mm.

Pit preparation

Construction work should take place during periods when the volume of groundwater is least. These are usually the warmest months of the year or the coldest. The pit can be dug manually or using an excavator.

In most cases, the two options are approximately equal in terms of financial costs, because you will need to spend the same amount on special equipment as on a team of people digging a pit. It is advisable to use an excavator, because... this saves a lot of time.

When carrying out digging work in the winter, it is recommended to first organize a fire at the site of the future pit.

Watch the video

To simplify the installation procedure and the possibility of creating external waterproofing to increase the tightness of the joints, it is recommended to dig a pit with a diameter of 50-80 cm larger than the diameter of the concrete rings. The required depth is calculated as the sum of three heights: ring products, filter pad (about 30 cm) and slab (about 15 cm).

The soil removed during digging can be immediately transported using the machine that delivered the concrete rings for the construction of the septic tank. A 2-tier pit is required, the depth of the second pit should be 60 cm greater. If this is not a single-chamber septic tank made of concrete rings, it is recommended to dig separate holes for all pits.

Trenches are also dug for laying the sewer pipeline; it must be located below the layer of freezing soil. Trench dimensions depend on the size of the reinforced concrete rings. In most cases they are about 1.5 m deep and 50 cm wide.

To ensure gravity flow of wastewater, the bottom must have a slope of 2-3 cm per linear meter. It is advisable to first calculate the distance between the end points; for this it is necessary to multiply the distance by the slope coefficient (it is determined by regulations).

After digging, the bottom should be well compacted and covered with sand 10 cm. Then it is concreted to a depth of 30 cm using cement mortar (3:1). There is no need to make a concrete bottom if a lower bottom ring is installed. Then it will be enough to pour a 20-centimeter cushion of crushed stone.

Installation of rings, installation of overflow pipes

First of all, install the bottom ring so that its walls are perpendicular to the bottom. Level installation will increase the strength, reliability and stability of the structure. When using a reinforced concrete ring without a bottom, a concrete screed is created. Its dimensions must exceed the annular diameter by 20 cm. The final formation of the screed may take up to 14 days.

Then install the first ring. This work cannot be done on your own, so you will need several people to help. After installation, the next ring is installed. To improve the fixation properties on the outside, special metal staples are used. Entry points are covered with concrete and insulation for safety.

Watch the video

Concrete rings for the septic tank are immersed into the pit using a construction crane. External voids are then filled with soil and sand. There is no need to rush; it is important to compact the soil evenly and alternate this with pouring water. Such backfill has shock-absorbing properties and is capable of draining storm and groundwater.

The layer located above the soil freezing level should be additionally insulated. If this is not done, the resulting ice plug will significantly reduce the quality of the cleaning performed. For insulation, you can use polystyrene foam or special thermal insulation materials.

To connect the sewer pipe, a hole should be drilled in the ring using a hammer drill. With the help of polyurethane foam, fixation is carried out, it also ensures the retention of excess moisture. Then the hole must be sealed.

Tees are installed on the overflow pipes, as well as those coming from the house. They allow waste liquids to be directed downwards and their processing to be accelerated. The use of tees is also necessary in order to provide constant access to clear clogs that have formed. It is advisable to cover overflow pipes with insulation.

Sealing joints and backfilling

To prevent the destructive effects of groundwater on the septic tank and protect it from leakage, all joints are sealed. Between the base and the lower ring, the joints are covered with a cement mixture that is resistant to moisture.

Tips and recommendations for installing a septic tank with high groundwater levels.

To waterproof a septic tank with your own hands, a special deep penetration impregnation or bitumen mastic is often used. Cement-based impregnations are used to treat rings. Sometimes liquid glass is added to a similar composition; it makes the joints resistant to high humidity.

Do not use strong chemicals for sealing. They are capable of destroying beneficial microorganisms that ensure the decomposition of biological waste.

Creating a filtration well

A filtration well, as a rule, is mounted only on soil that absorbs liquid well. About 1 m under this structure is covered with a soil filter. The bottom is first filled with sand (about 30 cm), then with gravel to the same thickness. The last layer is laid with crushed stone at a depth of 20-30 cm.

However, treated wastewater can leave not only through the bottom, but also through the side walls. If a similar design option is planned, then the reinforced concrete ring at the base should be perforated. The installation procedure for such a ring does not differ from conventional technology. The “pocket” between the outer walls and the ground is filled with crushed stone.

To create a filtration field, perforated pipes are used. They are placed on a layer of gravel and sand, which ensures the penetration of clean water into the ground. The top of the pipe must be covered with geological textiles and covered with soil.

How to put a septic tank into operation

In order for the system to begin to function effectively, the constructed septic tank must be saturated with anaerobic microflora. The natural accumulation process takes several months, so it is accelerated by saturating the septic tank with imported microflora. You can do this in two ways:

• The new septic tank is filled with wastewater and left for 10-14 days. Then sludge sludge from an existing anaerobic septic tank is loaded into it (2 buckets per cubic meter).
• You can purchase ready-made bioactivators (bacterial strains) in the store (the main thing here is not to confuse them with aerobes, which are intended for other treatment systems).

Ready-to-start septic tank made from rings Source remont-book.com

What rules must be followed when servicing a septic tank?

There are simple rules that support the high-quality operation of the system.

1. Cleaning. Twice a year, in addition to cleaning the drains, the septic tank must be inspected and the pipelines cleaned. Once every 5 years (or better yet, every 2-3 years) the bottom heavy fats are removed. The volume of sludge should not exceed 25% of the tank volume. When cleaning, part of the sludge is left to restore the microflora.
2. Quality of work. The wastewater leaving the system must be 70% purified. Analysis of wastewater in the laboratory will determine the acidity indicator, which will allow you to find out the quality of the drainage system.
3. Security measures:

• Work inside the septic tank is allowed only after intensive ventilation and using a safety belt (gases formed inside can be dangerous to human life).
• Increased safety measures are required when working with power tools (humid environments).

A septic tank made of concrete rings makes private housing more autonomous and, despite its shortcomings, it is one of the most reliable and durable options for treatment facilities for suburban real estate.

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Installation

Let's look at how a septic tank is installed from reinforced concrete well rings with an overflow. Construction time will be greatly reduced if the owner has the opportunity to use construction equipment - earthmoving (with its help, digging a pit) and lifting (for installing rings in place).

Pit preparation

First of all, you need to prepare a pit for installing the rings. The pit must have dimensions exceeding the dimensions of the chambers, and its depth is determined by the number of reinforced concrete rings .

In order for the chambers to be airtight, it is necessary to concrete the bottom; additional sealing is not required if the installation is carried out using rings with a bottom.

Construction of chambers

To build a septic tank from reinforced concrete with your own hands, you need to install the rings one above the other, avoiding distortions and shifts. This must be done using lifting equipment. The joints between the rings are covered with concrete mortar; this will make the chambers more durable; in addition, this is an additional sealing of the joints.

Waterproofing of a septic tank made of concrete rings is required. Waterproofing is carried out from the outside and inside, the joints are covered with bitumen mastic. Continuing the installation, you will need to make holes through which pipes will be supplied to the septic tank chambers. The connections between the pipes and the chamber must be sealed. That is, first they cover it with a solution, and then with sealing mastic.

The tops of the wells are covered with special covers. The septic tank requires ventilation. Properly organized ventilation is a guarantee that the septic tank made of rings will operate without odor. Ventilation is necessary to remove methane. It is an explosive gas, so ventilation is a way to keep people safe.

If the ventilation of the septic tank is not organized correctly, then the likelihood of unpleasant-smelling gases entering the house increases. Ventilation consists of two parts - a ventilation riser installed on the roof, and ventilation risers installed on the tank covers.

This ventilation ensures normal air exchange. It is recommended to backfill the pit using clay. This will provide additional sealing of the septic tank.