How to make a two-chamber septic tank from concrete rings: building instructions

Types of septic tanks

Rings made of concrete are used for the construction of various forms of local sewage:

1. A cesspool without a bottom is a simple well, the shaft of which is formed by concrete rings. The bottom is often filled with rubble. Liquid effluents penetrate the soil, the solid component accumulates at the bottom. This is the cheapest, but also unsuccessful construction, as it leads to soil pollution. According to the regulations, this method of sewage disposal is allowed only if the daily volume of wastewater does not exceed 1 m3.In addition, according to many experts, it is undesirable for black sewage to be dumped into a bottomless cesspool.
2. A septic tank is also a well, but it has a sealed bottom. In this building, sewage is accumulated. Periodically, it is necessary to call a sewer truck. The drive is suitable for small houses with a small daily volume of drains. Otherwise, this type of septic tank is not economically viable.
3. In the overflow version, 2 methods of mechanical water purification are used: settling and filtration. This type of septic tank consists of at least 2 wells. Some of it is biodegradable. If a compressor supplying air is installed in the second chamber of the overflow system, then a local treatment station is obtained. In this option, the maximum purification of wastewater occurs with the help of aerobic bacteria.

How to choose a place for a septic tank from turnkey concrete rings

Before drains penetrate the ground, they must be cleaned and neutralized. This is the purpose of the treatment plant.

Here, the organic component of fecal and sewage accumulations is divided into safe sludge and water suitable for irrigation of the territory. The septic tank as such does not affect its contents, but it creates conditions in which bacteria develop, decomposing organic matter into harmless elements.

In addition to compliance with the regulations of this document, you need to obtain a hygiene certificate that gives you the right to install a treatment plant in a selected location, as mentioned in SanPiN 2.1.5.980-00.

A septic tank should be installed at least 4m from the house and water pipes near it, moreover, at least 5m from the road.To build a septic tank in a selected place, you need to contact the sanitary and epidemiological station or the district administration for a building permit and a certificate.

You can build a septic tank without coordinating the construction with the local administration. However, if violations of legal requirements are detected, fines will not keep you waiting, as well as the requirements to transfer the capital structure to another place.

Calculation of a septic tank from concrete rings - we calculate the volume and performance

In order for the effluents to be completely cleaned, they must lie in the treatment plant for at least three days. Therefore, the volume of each section of the septic tank is calculated as:

Here: V is the volume of a separate section of the septic tank, Y is the rate of water consumption by one person (conditional), Z is the maximum number of people living in the house.

The septic tanks installed in accordance with this formula are very large, but they provide maximum purification of fecal and sewage effluents, making water and sludge suitable for irrigating the site, serving as fertilizer. The rate of water consumption is determined by many parameters.

Indoor water supply and sewerage of buildings meet the conditional norm of 95–300 liters per person per day.

You can calculate on your own how much water you consume, or use the SNiP table.

Thinking device concrete septic tank rings, it is better to adhere to the maximum values, and increase the number of residents by 50%. Although this will increase the cost of building a septic tank, you will eliminate the risks: if guests arrive, the septic tank will not overflow and the ground near the building will not be flooded with feces.

With this approach, construction costs are significantly reduced, and the degree of wastewater treatment becomes worse with an increase in the number of residents.

If the purified water is supposed to be discharged near the building and water intake points (up to 50 m), use the formula for the volume of one section.

If the distance is more than 50m, the formula for the total volume can be used. Undertreated drains removed to such a distance will not be dangerous.

Types of septic tanks made of concrete rings

Several types of septic tanks are built from reinforced concrete rings, and stations differ:

1. depth level;
2. ring diameter;
3. insulation.

The depth of the septic tank is determined both by its dimensions and by winter temperatures, more precisely, by the depth of soil freezing.

The lower it is, the lower the septic tank should be installed, since a strong drop in temperature (less than zero degrees) slows down or even stops the processes taking place in each section. Therefore, it is necessary either to deeply deepen the septic tank - all its sections, or to insulate each with foam or similar insulation.

It is possible to reduce the cost of installing concrete rings under the septic tank with a greater depth of the station, if not reinforced concrete rings, but a brick well are installed above the freezing depth of the soil, since the processes in the septic tank are greatly inhibited above the freezing depth of the soil even with high-quality insulation.

Septic tanks are also classified according to the number of their elements. Single-element pits are called cesspools and are considered ineffective.

The most effective design of three elements. A larger number of sections does not affect the quality of wastewater treatment. Three sections can be placed in the longitudinal direction, then the installation is very long, or in a triangle, when the area of ​​\u200b\u200bthe pit for the septic tank is reduced by almost a third, and with it the amount of soil that needs to be dug.

Project preparation

Even the simplest design of a septic tank or cesspool requires calculations, because the size of the structure depends on the daily amount of wastewater and other conditions. Only correct design will give confidence in the efficiency and reliability of the structure, and pre-drawn drawings will help to avoid errors in work.

Material calculation

The calculation of the number of rings is based on the volume of effluents, which, in turn, is determined on the basis of the amount of water consumed by the family. In your research, you can use the average data on water consumption per person in the amount of 200 liters per day, or resort to the help of special tables.

The dependence of the volume of the septic tank on the number of family members

To calculate the size of the receiving tank, the amount of wastewater per day is multiplied by three. Based on this value, the number of concrete rings and their size are determined. For example, a family of 3 would require a 1.8cc primary chamber. m. (600 liters per day times 3). For this, two standard rings with a diameter of 1 m and a height of 0.9 m will be enough. If 8 people live in the country house, then you will need a tank of 4.8 cubic meters. m, which is about seven reinforced concrete products. Of course, no one will build a seven-meter-deep septic tank. In this case, take three rings with a diameter of 1.5 meters.

When calculating, you can use tables of dimensions of standard reinforced concrete structures and formulas for determining the volume of a cylinder. For the most common rings with a diameter of 1000, 1500 and 2000 cm and a height of 0.9 m, the internal volume is:

• KS-10.9 - 0.7 cu. m;
• KS-15.9 - 1.6 cu. m;
• KS-20.9 - 2.8 cubic meters. m.

In the marking, the letters denote the “wall ring”, the first two digits are the diameter in decimeters, and the third is the height in tenths of a meter.

The minimum size of the post-treatment chamber should be at least 1/3 of the total volume of the septic tank

The size of the post-treatment chamber is calculated based on the fact that the first chamber occupies 2/3 of the volume of the septic tank, and the second - the remaining third. If we apply these ratios to our example of a treatment system for 8 people, then the second tank should have a volume of 2.4 cubic meters. m. This means that you can install 3 - 4 concrete elements KS-10.9 with a diameter of 100 cm.

When calculating the amount of materials, it is necessary to take into account the depth of the drain line, taking the entry point of the pipe into the septic tank as the upper level of the receiving chamber. The size of the structure is increased by an amount sufficient to ensure that the floor slab is 5–10 cm above the surface of the site. To do this, use one or two standard rings, and if necessary, supplement them with additional elements. If this is not possible, or after the construction of the cottage there is a red brick left, then the upper part of the septic tank chambers is built from it.

Drawing

Before starting earthworks, a detailed drawing of the structure is drawn up, indicating the depth, points of entry and exit of pipelines, levels of the overflow system. Since the distance from the surface of the site to the lowest point of the sewer line depends on the degree of freezing of the soil, these values ​​differ depending on the region and soil composition. In addition, it is imperative to consult with local experts about the groundwater level at the site, to which there must be a gap of at least 1 m from the bottom of the septic tank.Depending on this, a decision is made to increase the diameter of the chambers, which will entail a decrease in the height of the tanks. Drawings and diagrams can help in the process of work, you can be guided by them when drawing up your own design of treatment facilities.

Required Tools

The upcoming earthwork, installation and waterproofing works require the preparation of the following tools and materials:

• bayonet and shovel shovels;
• construction stretcher or wheelbarrow;
• solution containers;
• concrete mixer;
• perforator or impact drill with a nozzle for concrete;
• level and plumb;
• roulette;
• concrete rings, floor slabs and bottoms, hatches;
• pieces of pipes for the overflow system;
• bituminous waterproofing;
• sand and cement;
• rubble.

If it is not possible to use lower rings with a bottom (glass rings) or floor slabs and bases, then you will have to make these concrete products yourself. To do this, you will additionally need steel bars and reinforcement to reinforce the structure, as well as long corners or channels as supports for the upper plates. In addition, you need to take care of the formwork boards and the plastic film used for waterproofing.

How to make a septic tank from concrete rings - step by step instructions

This material is quite often used for the construction of overflow sewers. The advantages of such a system are ease of maintenance, affordability, speed of installation. In addition, concrete is a durable material that is resistant to damage.

Home-made systems consist of 2-3 functional wells, the purpose of which is the same as that of the settling tanks made at the factory.

The first two wells are the same size, or the second may be slightly smaller, both with a bottom.In the second, expanded clay, gravel and other fillers are poured, which have filtration properties. The third well has no bottom. Through it, the liquid seeps into the ground.

Video - Do-it-yourself septic tank without pumping

However, it is necessary to take into account the disadvantages of sewerage from concrete rings. These include:

• Difficult to use on loose soils, since the rings can move in the soil and relative to each other. Then it is better to fasten them together with metal fittings.
• The need for sealing joints between individual elements. Otherwise, the soil becomes contaminated with untreated waters.
• The use of special equipment, since the elements are quite heavy.

The scheme of construction of a septic tank from concrete rings

Step-by-step instructions for installing a septic tank from rings

Step 1. A common pit is dug out with an excavator, three holes are made in it for each ring. If necessary, the walls are reinforced with plank shields.

The use of heavy equipment

Step 2. The bottom is covered with a crushed stone layer 20 cm thick, rammed to get a horizontal surface.

Prices for crushed granite

Crushed granite

Lay gravel at the bottom

Step 3 Using a crane, all three wells are installed at the same distance of 50 cm. The first two wells must be located strictly vertically.

Installing concrete rings

Step 4. Holes are formed in the walls of the mines and overflow pipes are laid.

We install overflow pipes

Step 5 Install ceilings on wells.

We equip covers for wells

Step 6. Install rings of smaller diameter to build up the neck, protective hatches on the wells.

We mount rings of smaller diameter

Step 7. Seal the seams.

Seal the seams

At the last stage, the sedimentation tanks are insulated, the foundation pit is covered with soil and compacted.

The second way of arranging wells

According to another technology, you can first install the lower rings of the well, and then extract the earth from them. The disadvantage of this method is that it is more labor intensive. The difficulty lies in further insulation of the structure, installation of overflow pipes, etc. Yes, and the reliability of a septic tank built using this technology is lower. But the advantage is that all the work can be done independently.

Manhole Installation Tips

• For storage wells take concrete rings with locks. They provide better sealing than conventional ones and are less likely to move if soil heaving occurs during freezing.
• Before installation, concrete elements are impregnated with bituminous mastic or other waterproofing preparations.
• Sometimes a concrete slab 30 cm thick is poured under the wells. It should be of such a size that it protrudes from the sides of the wells to a distance of at least 20 cm. Then the first rings are installed no earlier than a month later.
• Brick and cement can be used to form the neck. From above, this part of the well is treated with waterproofing compounds.
• To install the third ring, the pit is deepened to sandy soil, which has the property of draining water. A pillow of crushed stone up to 25 cm thick is poured at the bottom, and then sand is added - 40 cm.

Perforated concrete ring

Whatever model of septic tank the homeowner chooses, it is important to remember that all work must be carried out in accordance with building codes.Only then the system will be effective and perform the functions assigned to it.

Preparatory stage

Before you make a septic tank from reinforced concrete (RC) rings, it is necessary to carry out preparatory work. It will be necessary to calculate the volume of the chambers, then a septic tank diagram of concrete rings should be drawn up. Then choose a good place for construction, as well as purchase the necessary materials.

Calculation of chamber volume

A septic tank made of concrete rings must have sufficient volume. This device works effectively if the wastewater is in the chambers long enough. To make a correct calculation of the volume of chambers, you need to know how much water the residents of a private house spend per day. According to the norms, the volume of effluents that is formed in the house in three days should fit in the installation chamber.

But how to make a calculation and find out how much water is consumed by the inhabitants of the house? To make a calculation of the volume of the chambers, it is worth considering that each tenant consumes approximately 200-250 liters of water per day. Thus, the calculation of the daily consumption is carried out according to the formula: we multiply the water consumption by the number of residents of a private house.

Charting

After the volume of the chambers has been calculated, you can begin to draw up a septic tank diagram for a frequent house. First of all, you need to decide how many chambers the installation will have, it depends on the amount of wastewater to be processed:

• If the house consumes no more than a cubic meter of water, then it is recommended to build a home-made single-chamber septic tank;
• In the event that the water consumption is from 1 to 10 cubic meters, then it is necessary to build a two-chamber septic tank from concrete rings;
• With a water flow rate of more than 10 cubic meters, it is necessary to plan the manufacture of an installation consisting of three chambers, sedimentation tanks and a filtration well.

Selecting a location for installation

In order for septic tanks assembled from reinforced concrete rings to work efficiently and not cause inconvenience to the owners of the house and their neighbors, it is necessary to correctly choose the construction site:

• you can’t place it close to the house, the distance should be at least five meters, and other buildings (for example, a garage) - a meter;
• It is necessary to locate the unit as far as possible from the source of drinking water. The minimum distance is 50 meters;

Where to buy materials?

Before you start building septic tanks from rings, you need to purchase materials for the manufacture of chambers. Well rings have standard sizes and, accordingly, a standard volume.

The height of the rings is, as a rule, 1 meter, but their diameter can be different. It is necessary to choose the sizes of the rings, taking into account what dimensions, according to the calculations, the chambers should have.

This is interesting: How a septic tank works - device diagram and principle of operation

Joint sealing

The problem of sealing a septic tank from concrete rings Khozain2000 solved in this way. He bought factory rings with a quarter - these locks on the products do not allow the rings to move. Before proceeding with the installation of the septic tank and starting to install the rings, the forum member treated them with a waterproofing mixture from all sides, in three layers. And when installing the rings, to seal the joints, I added "liquid glass" to the solution.

Sealing of the bottom took place in two stages:

1. Filling reinforced screed under the ring, the thickness is 5-7 cm.
2. Processing the screed with a waterproofing mixture and installing another screed on top.

Khozain2000:

- Because coating waterproofing does not work well for separation, and water creates pressure in both directions, then a screed must be needed on one and the other side.

To maximize the useful volume of the septic tank from the rings, the cameras were installed at a depth of more than 80 cm below ground level. Then the member of the forum put polymer-sand cones on this base and laid cylinders out of brick at the ground level, on which he then put covers (manholes).

An interesting point of view is a member of the forum with the nickname DmitryM on the need to seal the rings.

In his opinion, it is almost impossible to achieve perfect sealing of the joints and the bottom, and it is not necessary.

And the process of a small seepage of effluents into the ground will first stop by itself during the year of operation.

Khozain2000:

“I think sealing is still important, and here’s why. In the spring, when the snow melts, there is a lot of perched water. If the receiving well and the sump are leaking, then melt water will flow into them and flood the septic tank.

Construction options

The design of a septic tank made of concrete rings is not difficult. It can be a two- or three-chamber structure. Single-chamber drives, operating on the principle of cesspools, are used much less frequently.

The number of storage and filtration tanks in such a treatment plant, depending on the volume of liquid processing, can be two or three

Regardless of the type of design, it will be necessary to involve sewage equipment during its maintenance. It will remove solid waste that accumulates on the bottom and walls of storage tanks.

Single-chamber septic tanks are chosen when designing a sewer system for small country houses of seasonal residence, provided that the volume of effluents is small. Good reasons for installing a single-chamber reservoir also include the high level of groundwater and the predominance of clayey rocks in the geological section of the site.

Two- and three-chamber structures are installed when laying autonomous sewers for cottages intended for year-round use with large volumes of wastewater.

The best option for a local treatment plant is the installation of a septic tank, which includes two tanks

When arranging a two-chamber structure, supplemented by a filter well or a filtration field, the first compartment is a sealed container with a limited supply of oxygen.

It is equipped with a cast-iron or concrete hatch, as well as an inlet and outlet for drains. The second compartment for creating oxygen access conditions is equipped with a ventilation pipe.

During the construction of a purifier, which includes two or three tanks, the effluents will be subjected to multi-stage purification by settling and filtering:

• In the first accumulator, the primary purification process is carried out, during which large suspensions are deposited and decompose under conditions of lack of oxygen, and organic matter is processed by anaerobic bacteria.
• In the second chamber, the purification and filtration process continues, but with the participation of oxygen and aerobic bacteria. The decomposed remains of organic matter in the form of silt settle to the bottom, and the clarified liquid enters the drainage, which is also an absorption or filtering well.

The water that has undergone post-treatment flows into the drainage well, from where it goes into the ground through the holes in the walls and passing through the filtration through the sand and gravel layer.

The scheme of the septic tank from the rings includes two working chambers interconnected by a thick overflow pipe, and the third column acts as a drainage well

If the land plot is located on soils with good filtration properties that absorb and pass water well, and at the same time the groundwater level is not high, it is worth considering the option of arranging a septic tank, in which the clarified liquid is discharged into an absorption well.

In areas with a groundwater level reaching only 2.5 m, the process of ground purification is most often impossible, since there should be at least a meter between the lowest point of the drainage well and groundwater. In this case, it is better to divert the drains cleaned by the septic tank to the draining fields.

The arrangement of such systems requires large squares of space. But under given conditions, sometimes only such a system works.

List of required tools and materials

A ready-made septic tank costs a lot of money, it is much cheaper to make it. A do-it-yourself septic tank, without the need for pumping, must have at least 2 containers in the design, which are connected by a pipe. In such cases, sewage will enter the first tank and preliminarily settle, after filling such a tank, the sewage will go by gravity into the second tank.

It also screens out both heavy and light fractions. The heavy ones eventually settle to the bottom and continue to rot until the sewage clarifies.After filling this compartment of the device, the liquid flows into the filtration chamber, it is equipped with a bottom with the so-called perforation, and filter material.

Do-it-yourself septic tank from concrete rings

Broken brick or crushed stone is quite suitable as a material for filtering. But under this layer, a sand cushion is additionally laid. If desired, the filtered liquid can be diverted to additional facilities from which water enters the sump. Using this filtration method, you can water garden plants, as well as fertilize the soil.

To construct a do-it-yourself septic tank that functions without pumping out, people use a wide variety of materials and tanks.

Among the entire range are popular:

• Clinker brick.

  To design septic tank compartments, you must have experience with bricks. After forcing the walls of the structure from the outside, it is advisable to perform waterproofing by applying mastic and filling the distance with clay. In the middle of the chamber, the brick is plastered.

• Solution. The bottom of the structure is first poured with ready-made concrete, then the formwork is installed, and the walls are poured. During the construction of the formwork, it is necessary to strengthen the structure, and reinforcement is used for this. After the solution dries, the product is treated with sealants.
• The best option for building this is a do-it-yourself septic tank made of concrete rings, the scheme is presented above. Such a system is considered easier, since the rings are already ready, they are installed in a dug hole, on top of each other, but it is not advisable to use more than 3 pieces for one chamber. It is this amount that is necessary so that the product does not sag under its own weight.During the installation of a septic tank from concrete rings according to the scheme, it is better to use a winch or call special equipment. Upon completion, the seams are qualitatively sealed with mortar and treated with bituminous mastic for better sealing.
• Plastic and metal tanks.

  They are perfect for do-it-yourself septic tank equipment in the country house operated without pumping, especially if there are old, but whole containers. The disadvantage of metal containers is considered to be low resistance to corrosion. Here, a plastic barrel is ideal for such an installation, as they are resistant to external influences, tolerate sub-zero temperatures and do not deform under ground pressure.

When choosing a material, the following criteria must be taken into account:

• The quality of incoming waste;
• Distance to groundwater;
• Indicators of building material;
• Individual building abilities and personal opportunities regarding money.

After all, if you decide to equip a septic tank with your own hands, using a brick, but do not have masonry experience, then you will have to call a bricklayer and spend extra money on this.

To design such a system, you must have the following material and tools:

• Crushed stone, cement and sand;
• Reinforcement or rods with a cross section of at least 1 cm;
• To organize the overlap, you need a corner, pipes, and preferably a channel;
• To construct the formwork, you will need timber, slats and boards;
• Nails and screws;
• Means for carrying out isolation;
• A container for the mixture and measurements of the material, as well as a concrete mixer for mixing;
• Bulgarian, wood saw and welding machine;
• Rammer and hammer;
• Screwdriver or electric drill with a nozzle for self-tapping screws;
• Roulette and building level.

When it is necessary to insulate not only pipes, but also the septic system itself, additional material is needed, mainly expanded clay or mineral wool.