It is best to start building a country house with the installation of a sewer system. Agree, correctly designing and organizing wastewater drainage on a site is not an easy task. We will have to think carefully about solving this problem. After all, improper installation of sewerage threatens to make life in the house unbearable.
We will tell you how to create a functional septic tank on your site yourself. Thus, among the affordable materials used in the construction of local treatment facilities, the most popular today are concrete rings.
We will talk about how to build septic tanks from rings with your own hands, and what to consider during the installation process. In addition, in the article you will find videos with advice from experienced specialists, detailed instructions for installing a septic tank, as well as many useful recommendations about installing a sewer system in a country house.
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.
Features of pipe laying
There are several tips on how to make a pipe system so that it functions correctly and without failures:
- The pipe that is supplied to the first storage well is installed at a slight slope from the house to the septic tank.
- The pipe connecting the first and second tanks should be located 20-25 centimeters below the first.
- The third pipe is installed another 20 cm lower.
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.
Operating principle and device
The design of the simplest cesspool with an overflow well includes two objects connected to each other by a piece of pipe.
The first is a large-sized sealed container, constructed on the principle of a storage tank with impenetrable walls and bottom.
The second part of the structure is arranged in exactly the same way as the filtering version of the sewer well. This means that it does not have an impenetrable monolithic bottom. Instead of a solid concrete slab, a kind of filter with a thickness of 1 m or more is built in the area where the conditional bottom is constructed.
The filter is made in the form of a backfill made of materials with high filtration properties: crushed stone, slag, gravel and/or sand.
A cesspool with an overflow is installed to increase the degree of wastewater treatment, which makes it possible to partially discharge it into the ground, filtration fields, sewer ditches or wastewater bodies
The walls can be made either solid or with holes to increase the rate of removal of processed waste from the filter well, otherwise called the absorption well.
The simplest design of a cesspool with an overflow compartment includes two parts, the first of which serves as a storage tank, the second as a absorption well
The cesspool and the filter well are connected by an overflow - a tube located at an angle towards the absorber. The depth of its placement depends on the climatic data of the region, i.e. like any pipeline laid in the ground, the overflow must be below the level of seasonal freezing of the soil.
A sewer pipe is connected to the storage tank, through which wastewater will flow from the internal sewerage system into the storage tank.
The diagram shows in detail the principle of constructing a cesspool with an overflow section. The pipe connecting the sections of the structure must be located at the correct height and with a slight slope
A ceiling with a hatch designed for pumping out the contents is installed above the cesspool. The ventilation pipe is mounted in such a way that the lower edge is above the drain horizon at any degree of filling. The second end of the pipe is brought to the surface.
For a cesspool with one filter well, you can build only one ventilation duct, but it is better to equip each compartment of a simple treatment plant with its own ventilation.
This design makes the wastewater treatment process more efficient and faster. First, all waste enters the first sealed chamber. Here they accumulate and decompose under the influence of bacteria. Gradually, there is more waste, the liquid level in the chamber rises and reaches overflow.
As the storage tank is filled, the excess that has settled and partially purified by bacteria is poured into the next well through a pipe built into its wall.
The insoluble part of the wastewater settles at the bottom, and the partially clarified with the participation of bacteria and settled liquid component, as it fills, reaches the level of the overflow installation and moves by gravity into the absorption well, in which the sewer mass is further purified.
In a filter well, wastewater passes through the drainage layer and enters the ground, once again being further purified through a natural earthen filter. And solid waste in the form of silt deposits accumulates in a sealed compartment of the cesspool, from which it is subsequently removed and, if desired, used by the owners as a starting material for preparing compost.
Why are such complications necessary, since it is easier to pump out the sewage mass from the cesspool and thus get rid of it? The presence of two containers significantly increases the size of the sewage system; part of the wastewater, after undergoing natural treatment, is transferred to the ground, due to which the number of calls for sewer trucks is significantly reduced.
Increasing the number of sewer wells allows you to receive and process more wastewater and improves the quality of treatment
As the number of overflow wells increases, the scheme becomes somewhat more complicated. However, this increases the time from the receipt of waste into the container to the transfer of the liquid component into the ground. This makes it possible to improve the quality of wastewater treatment and make it safer for the environment.
Practice shows that a treatment plant consisting of two or more wells produces significantly less unpleasant odors than a conventional version of this type of construction. Usually there are either no odors or they are insignificant. The use of special bacteria will help improve the situation with the processing of sewage mass and the elimination of odors.
The unpleasant squelching sounds that an overfilled cesspool makes are absent in a design with an overflow. Owners of such structures usually do not have to save sewer resources. They can enjoy the water without worrying about their sewer overflowing.
It is advisable to locate the local sewerage system so that it does not interfere with movement around the site and provides access for emptying and maintenance if necessary.
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.
Preparation
After determining the location for the septic tank and calculating the required volume of wastewater, you can easily determine the required volume of the septic tank. The number of concrete rings, slabs for the bottom and covering depends on its volume (you can use ready-made rings with bottoms).
After purchasing and receiving all materials, you must:
Prepare the pit. It is worth digging a pit for all chambers at once (a large pit), with a margin of 0.5-1 meter for mounting rings on each side. The depth of the pit must correspond to the full height of the septic tank.
Level the bottom of the pit and cover it with a sand cushion 0.1-0.2 meters thick. Press down the pillow.
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Digging of a pit should be carried out only by mechanized methods. When constructing septic tanks of small volumes (up to 4 cubic meters), you can do it manually.
Buy cement, sand, crushed stone, sewer pipes, bitumen mastic, well hatch. Make sure you have the necessary tools.
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 to save on construction?
If it is not possible to use special equipment during installation and finances do not allow you to attract a team of workers, try using these methods.
Instead of traditionally digging a pit and then immersing rings in them, use a technology in which the soil is removed gradually as the ring is deepened. It is built on the fact that the ring falls down under the influence of its weight. The master’s task is to dig up the soil inside the ring and under its wall.
The technology of “undermining” rings laid on the ground is used only when installing products without a bottom
In this case, the concrete bottom will have to be poured later. And it will be located exclusively inside the ring.
A significant drawback of the described method is the inability to perform thermal and waterproofing on the outer walls of the structure. In addition, due to the fact that the bottom is located inside the ring, the reliability of the structure is reduced.
In an effort to reduce the cost of the structure itself, craftsmen offer an option for constructing a structure that looks like a triangle.
Storage tanks act as the basis of an isosceles triangle, and their common neck is its vertex
By choosing this arrangement option, you will save space for placing rings and can significantly reduce the amount of land work.
But during installation, take into account the peculiarity that the inspection entrance in such a design will be one per three rings. Therefore, all overflows should be placed outside its accessibility.
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.
Which rings to choose - with or without a lock?
Concrete rings with a lock (tongue-and-ridge connection) and without it are available on the market. There is an opinion that the former provide higher water resistance and better protect the septic tank structure from lateral movement.
However, according to experts, this is not true. In practice, there is no big difference between both types of rings in terms of water permeability. If there are such significant shifts in the soil during frost heaving that, in principle, they can displace one ring relative to another (the weight of one ring with a diameter of 1 m is 600 kg), then the lock will not save. As for the convenience of centering rings with a lock during installation, this is only true for a structure of two rings. In the case of a septic tank with three or more rings, the difference is unlikely to be noticeable.
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
Location of the structure
When designing a septic tank, the sanitary zone is placed in such a way that organic waste cannot penetrate into drinking water and fertile soil. To do this, when choosing a location, you should be guided by sanitary and building codes and regulations.
The correct location of the cleaning system on the site is regulated by:
- SNiP 2.04.03.85. It sets out the rules for the construction of external sewerage structures.
- SanPiN 2.2.1/2.1.1.1200-03. It lists the requirements for creating zones that are environmentally hazardous.
According to the standards, in order to avoid the foundation getting wet in the event of emergency leaks, the septic tank must be placed lower than the house is located.
Failure to comply with these requirements may result in a risk of untreated wastewater penetrating into aquifers (+)
When choosing a location, you should definitely take into account the presence of bodies of water with running water, maintaining a distance of 5 m to them. The distance from trees should be 3 m, from bushes - reduced to one meter.
It is also necessary to know where the underground gas pipe is laid. The distance to it should be at least 5 m.
Since the construction of purifier chambers from rings involves the construction of a pit and the use of special equipment, when choosing a location it is worth providing free space for its access and maneuvering
But keep in mind that the machine cannot be placed directly above the deepening site of the treatment plant. With their weight they can destroy the entire structure.
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
Flaws
Despite the fact that more and more owners of private houses are choosing this design, it is also not without its drawbacks:
- It is necessary to involve construction equipment (at least a crane);
- The system takes up quite a lot of space, so it is problematic to install it in small areas.
- Care must be taken to ensure that the structure is airtight.
- It must be cleaned periodically using vacuum cleaners.
What rules must be followed when servicing a septic tank?
There are simple rules that support the high-quality operation of the system.
- 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.
- 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.
- 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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Septic tank installation technology
There is nothing difficult in making a reliable and durable septic tank from rings. When designing several compartments, a linear construction principle is used, in which all concrete columns from rings are lined up along one line.
The receiving compartment and the following tanks are placed in close proximity to each other, and the filter column is located at a slight distance from them.
Step #1 - measurements and design
One of the prerequisites for effective wastewater treatment is to create conditions for it to remain inside the walls of the septic tank for at least three days. Therefore, the dimensions of the chambers are determined using the total three-day volume of wastewater as a basis.
According to standards, the daily volume of water consumption per household, subject to the use of household appliances, is about 200 liters.
So for a family of two or three people, the minimum volume of a treatment plant should be about two cubic meters. A family of 5-6 households will require a more spacious structure with a volume of 3-4 cubic meters.
When calculating, only the volume of the septic tank compartments is taken into account; since the filter well is not one of these, it is not taken into account (+)
But when determining the volume of the structure, it is worth making a small reserve. After all, if guests arrive, there is a risk of “overfilling” the norm. And eliminating the consequences is a rather complex and at the same time expensive procedure.
The table below will help you determine what size rings you will need and in what quantity.
Marking and dimensions of manufactured reinforced concrete rings indicating the outer/inner diameter, weight and volume
When choosing rings, keep in mind that the actual volume of the column must be clearly higher than the calculated one. This is due to the fact that as the drains fill, they rise only to the level of the overflow holes and never reach the top edge. Therefore, the calculated volume of liquid must be placed up to the level of these pipes.
Step #2 - preparing the necessary materials
When choosing rings for a septic tank, it is advisable to buy products with locks. The presence of locks not only simplifies the installation process, but also prevents their displacement under the influence of frost heaving. When purchasing products, you need to pay attention to the evenness of the seats and carefully inspect the integrity of the locks.
In addition to the rings themselves, materials and construction tools will also be required:
- sewer pipes;
- fine crushed stone;
- river sand;
- polyurethane foam;
- cement mortar;
- waterproofing compounds;
- rolled thermal insulation materials;
- building level;
- ladder;
- perforator;
- wide brush;
- container for mixing the solution.
To create overflows between wells, you will need asbestos-cement or polypropylene pipes marked “for external sewerage.”
Polypropylene pipes are famous for their strength and elasticity; their operating temperature is about 65°C
The diameter of asbestos-cement or polymer pipes used for overflow should be 110-120 mm.
Step #3 - digging a pit and arranging the bottom
It is better to carry out excavation work after the onset of the first frost or in the hottest months. During this period, the lowest groundwater level is observed.
The pit can be dug manually, by hiring a team of “diggers”, or by using the services of an excavator. If we take into account the costs of carrying out excavation work, then the costs of a team of diggers will be comparable to the amounts that will be spent on calling out special equipment.
The dimensions of the finished pit should exceed the dimensions of the installed rings by 50-80 cm. This will simplify the installation process and allow for external waterproofing of the joints of the structure.
When calculating the pit depth, three values are summed up: the height of the monolithic or filtration bed (20-30 cm) + the height of the rings (indicated in the table) + the height of the slab (15 cm).
It is better to immediately remove a large amount of soil removed from the pit from the site, using the same machine that delivered the rings
The pit for installing the treatment plant should be two-tiered: its second tank should be buried 50 cm lower than the first. Alternatively, dig your own hole for each tank.
To connect sewer pipes, trenches are dug, laying them below the freezing depth of the soil. The width and depth of the trenches are selected based on the dimensions of the rings used for the construction of the tanks. Most often they are made 50 cm wide with a depth of 1.2-1.5 m.
The bottom of the dug trenches should be located at a slope of 2-3 cm, distributed per linear meter. It is better to calculate in advance the difference between the extreme points, multiplying the distance between them by the slope value stated by the standards.
Compliance with this condition will ensure gravity flow of the liquid. The leveled and compacted bottom of the trenches is covered with sand, forming a layer 10 cm thick.
The bottom of the pit is carefully compacted again. For concreting, standard cement mortar prepared in a 3:1 ratio is used.
If you plan to install a lower ring equipped with a bottom, you don’t have to construct a concrete screed. In this case, you can limit yourself to crushed stone filling, forming a layer 20 cm thick.
The bedding created after compaction must have a flat horizontal surface, free of differences
It is necessary to achieve an effect in which the pillow sags as much as possible. To thoroughly compact the embankment and achieve maximum density, tamping is alternated with filling the fill with water.
Step #4 - installing rings and sealing seams
The construction of a septic tank begins with the installation of its closed part - the lower ring, equipped with a bottom. It is set exactly so that the walls are positioned strictly vertically. Compliance with this condition will ensure the strength and stability of the structure.
When using a ring without a bottom as a base, the bottom of the pit must first be concreted. To do this, pour a concrete screed 30 cm thick. The dimensions of the created concrete screed should be 20 cm larger than the diameter of the immersed ring.
An option for pouring the base for a three-chamber septic tank, the tanks of which are arranged not in a straight line, but in the form of a triangle
It can take up to two weeks for the concrete to harden. As soon as it acquires the necessary strength, install the first ring. Laying the rings without outside help is almost impossible. This work is performed with two or three assistants.
To protect the structure from leakage and reduce the harmful effects of groundwater on concrete, the joints between the base and the lower edge of the ring are thoroughly coated with waterproof cement mortar.
Ideal for waterproofing materials:
- bitumen mastic;
- deep penetration impregnation.
As an impregnation for treating concrete rings, it is good to use cement-based compositions such as “Penetron” or “Aquacement”.
When sealing joints, liquid glass is often added to cement mixtures, which increases the resistance of the joints to excess moisture.
Toxic compounds must not be used for internal processing. During operation, they can destroy bacteria that are responsible for the decomposition of bio-inclusions.
All subsequent ones are installed on the first ring one by one. To create a more durable fixation, metal brackets are installed on the outside of the structure. The “entry” points of the staples are concreted and covered with a layer of insulation.
Immerse the rings into the tank using a tap. The resulting joints between the elements are also carefully sealed. The voids between the outer walls of the tank and the pit are filled with a mixture of soil removed when digging the pit and sand.
The “pockets” should be filled evenly, alternating compacting the soil composition with filling with water.
Such a layer will perform a dual function: drain rain and groundwater, and also serve as a shock absorber
The upper part of the structure, located above the soil freezing level, should be insulated. In severe frosts, there is a high probability that an ice plug will form inside the tank. And this significantly reduces the speed and efficiency of cleaning.
It is convenient to use as a heat insulator:
- pieces of expanded polystyrene;
- finished shell products.
At the top of the columns, necks with holes for sewer hatches are installed. They are equipped with concrete or cast iron covers.
The second compartment of the purifier is equipped with a ventilation pipe. It should rise 70-80 cm above the ground surface.
Image gallery
Photo from
Finishing concrete ring
Method for narrowing the neck of a septic tank
Sealing the butt seams of the well
Installation of ventilation pipes
Step #5 - installation of overflow pipes
The location of the overflow pipes is determined by the level of the pipe leading from the house. Since the overflow septic tank device is designed to ensure the movement of liquid by gravity, the highest point of the sewer pipe must be located below the freezing level of the soil.
The overflow on the opposite wall of the tank should be approximately 15-20 cm below the supply point.
The overflow between the second tank and the filtration column can be done at the same level, or the same 5 cm can be maintained
To connect the sewer pipe, a hole of the appropriate size is made in the wall of the ring using a perforator. The easiest way to fix the pipe in concrete is with polyurethane foam. It will retain moisture and act as a damper pad.
The entrance of the pipe to the tank wall is carefully sealed. The inlet pipes coming from the house, as well as the overflow pipes between the chambers, are equipped with tees.
The main purpose of the tee is to direct wastewater downward in order to improve its processing and prevent crust erosion
Tees at the ends of the outlet and inlet pipelines will provide unobstructed access for clearing blockages.
To increase the resistance of pipes to the most severe frosts, it is advisable to apply a layer of insulation to them and cover the top with a protective casing.
Choosing a location for a septic tank, installing a filter well
The choice of location for the septic tank is carried out taking into account regulatory requirements (5 m from the house, 30-50 meters from the water intake or reservoir). The second criterion is service. Although septic tanks do not require frequent pumping like cesspools, the containers must be freed from solid sediments - otherwise they will form a large layer of “mineral” deposits at the bottom, and this will reduce the performance of the treatment system.
When biologically purifying wastewater in wells or fields, it must be taken into account that they are installed in soils with good filtering properties - sand and sandy loam.
Restrictions when installing septic tanks Source 1beton.info
For low-filtration soils, filter trenches are installed after the septic tank to collect water in storage tanks for irrigation or discharge into a nearby body of water.
If, based on the geological features of the site, a scheme with trenches and filtration fields is chosen, then it must be taken into account that only a lawn can be laid out on their area or small shrubs with a shallow root system can be planted.
Sewerage from rings Source pinterest.com
The filter well does not have a sealed bottom - instead, it is backfilled with a mixture of gravel (crushed stone) with screenings or coarse sand. The height of the backfill is about 30 cm. They no longer do it due to difficulties during subsequent replacement.
The rest of the load for filtering treated waste is taken up by the backfill around the “perforated” walls of the well. The recommended layer thickness is 30 cm. Perforation of the walls should start from the bottom and end at the level of the pipe entrance from the overflow of the last chamber of the septic tank. For the walls, either ordinary well rings are used, in the walls of which, before installation, holes with a diameter of 3-6 cm are made (with a total area of at least 10% of the total), or special perforated rings for drainage wells are installed.
Conclusions and useful video on the topic
The diagram for quick installation of a cesspool is clearly presented in the following video:
An overflow cesspool is, of course, a more modern and convenient version of a conventional cesspool. Of course, creating a two-chamber or even three-chamber structure requires more material costs, time and effort. But all this will more than pay off in the future, when the residents of the house feel the effect of using a reliable sewer system that requires minimal maintenance.
If you have experience in constructing overflow cesspools or have already encountered this issue and have something to share with our readers, please leave your questions or valuable tips below in the comments.
