Collection, purification and disposal of wastewater from the site is one of the most important tasks for ensuring comfortable living in a private country house. This article will describe the step-by-step process of constructing a sewer system from concrete rings with your own hands.
One of the most popular materials for solving this issue is concrete rings.
Devices made from such elements for a private home are the most durable, require virtually no repairs during operation, are financially affordable for any budget and are easy to install.
Features and advantages of concrete rings
The choice of materials for constructing containers, the main elements of an autonomous sewage system, is large: brick, metal, plastic, monolithic reinforced concrete, concrete rings.
Ordinary ceramic brick is used for these purposes if it remains in excess after construction. Its porous structure, hygroscopicity (water absorption of at least 8%) and the presence of a large number of masonry joints require comprehensive internal and external waterproofing of the tank using coating and roll materials to prevent groundwater from seeping in and wastewater from leaking out.
Metal containers can be used with a reservation - only in anaerobic septic tanks, when the flow of oxygen inside is limited by the design and principle of operation. In aerobic septic tanks in a humid, aggressive environment with forced air injection, the walls, and especially the welds, will quickly rust.
Plastic containers have virtually no disadvantages. But there are restrictions on use - they are “light”, and even when filled with wastewater, they will remain lighter than denser soil. When exposed to soil heaving forces, they can be literally squeezed out to the surface if they are not secured to a reinforced concrete slab installed as the base.
If the plastic septic tank is not secured, then heaving forces can very soon squeeze the container to the surface Source mirhat.ru
It is also advisable to strengthen the walls of the pit and provide a protective structure for the tank so that it takes loads from above.
Pouring monolithic reinforced concrete into formwork and its maturation takes a long time, significantly increasing the time from the start of construction to the commissioning of the sewerage system
Sewerage for a private house from concrete rings is built quickly, the design of the tanks has high rigidity and strength, and construction costs are low. And the reliability and durability of this material is evidenced by the fact that the main components of the central sewerage treatment facilities are made of precast reinforced concrete.
Creating cameras
It is impossible to install the rings without a manipulator. Firstly, they are very heavy, and secondly, it is not recommended to move them or move them manually to avoid cracking.
First, the frame is assembled. The required number of rings, according to calculations made in advance, are installed one after another on top of each other. A fastening layer is placed between the rings to ensure their high-quality connection - this could be, for example, a special glue or mortar. You should also pay attention to the junction of the first ring with the base - this place requires particularly careful sealing with glue or mortar. If you add liquid glass to the mortar, this will further increase the waterproofing properties of the composition (10 grams per 1 kg of cement).
Important! You cannot use polyurethane foam; it is a poor sealant and is completely unsuitable for these purposes, because... turns into dust in about a year.
There are several ways to seal seams:
- The most common method is plastering. This method allows you to seal joints both inside and outside. They work with spatulas. Sealing is done by pressing the solution between the rings and into places where there are cracks in the rings themselves. Lastly, coat the joint surface with the solution and spread it evenly.
- by coating with bitumen mastic. The work is done with a wide brush. The tar is applied evenly. One layer is not enough. At least three layers should be applied one at a time. In order for the tar to better adhere to the surface of the ring, it is recommended to make the first layer by mixing resin and gasoline in proportions of 1 to 4, and the remaining two – 1 to 1.
- by sealing with roll waterproofing. A layer of waterproofing - it can be roofing felt, for example, it is fused onto the upper rings. This type of insulation protects against groundwater, on the one hand, and on the other, does not allow runoff from the tank to leak into the ground.
- by filling with sealants. The choice of method is influenced by the characteristics of the soil, how deep the drinking water is, etc.
It is best to not only seal the seams, but also treat the entire body of the well with one of the types of waterproofing, both outside and inside.
You can waterproof the inside with cementitious compounds and materials, or you can use plastic inserts. However, if the first type of work is easy to do with your own hands or with the hands of laborers, then it is better to entrust the work with plastic inserts to specialists. Waterproofing a well from the inside can only be done with an assistant, as insurance is required.
From above, all containers are individually covered with special reinforced concrete lids. Each cover must have a hatch and a hole for the ventilation pipe.
Sewage schemes made of concrete rings
Sewerage from concrete rings is made according to different schemes. The specific type depends on the seasonality of residence, intensity of operation, financial capabilities for purchasing additional equipment and paying operating costs.
The following options can be distinguished:
- Storage septic tank. Behind this name lies an ordinary cesspool with a waterproof bottom and walls. Tightness is a mandatory requirement, failure to comply with which, according to the administrative code of the Russian Federation, is regarded as damage to the land. When the wastewater fills the container, a sewage disposal truck is called.
A storage septic tank is simply a container into which wastewater is collected Source pinterest.pt
The smaller the capacity and the higher the intensity of operation of the points connected to the sewer, the more often you need to call the car. This is often how country sewer systems are constructed from concrete rings.
Note! The term “septic tank” in this case is not used entirely correctly, since by definition it is a treatment facility with waste flowing from chamber to chamber.
- Anaerobic septic tank. Two-, less often single-chamber, septic tanks, in sealed containers of which wastewater is purified by anaerobic bacteria (without access to oxygen). The number of chambers and their volume are chosen so that at the exit of the septic tank the wastewater is purified by 65-75%. Post-treatment occurs in filtration wells (“without bottom”), trenches or fields with aerobic bacteria (it is called “biological treatment”). Only after this can wastewater be discharged into the ground. The scheme is very popular among owners of country houses and dachas due to the simplicity of the device and energy independence. The disadvantage of the scheme is that it is necessary to periodically change the sand and crushed stone in the filter structures, in which case they have to be opened and the used material must be disposed of (although this is done infrequently).
Diagram of an anaerobic septic tank made of reinforced concrete rings Source o-cemente.info
See also: Catalog of companies that specialize in water supply and sewerage.
- Aerobic septic tanks and biological treatment stations. There is also a phase of primary accumulation and partial processing of feces with the help of anaerobic bacteria. The principle of operation is the clarification of wastewater in the absence of oxygen, and additional purification in the last chamber by aerobic bacteria under conditions of forced air injection. The purity of the wastewater at the outlet is considered to be 95-98%, and it can be discharged into the ground or used for irrigation. Disadvantage: aerobic bacteria die if the air supply compressor does not work. And this happens when the network is poor due to power outages.
The operating principle of aerobic septic tanks is that electricity is required for operation. Source prostroyer.ru
External waste disposal system
Sewer rings are the main component of its outer part, performing the functions of containers for various purposes in a wastewater treatment system. Products used are walk-through, without a bottom and equipped with bottoms. In addition, covers in the form of concrete slabs with a passage opening for maintenance are a mandatory element. For filter wells, rings with perforated walls are also used, in which a bottom filter is installed.
The finished container is equipped with two lids - an inner wooden one and an outer plastic or cast iron one. Concrete sewerage products are immersed in the ground to a depth that ensures that only the top cover protrudes outward.
The advantages of using such products include the following properties:
- strength, allowing you not to fear damage when the soil freezes in winter;
- durability - high-quality products of standard quality can serve in the sewerage system for up to 50 years;
- ease of installation - do-it-yourself reinforced concrete sewerage is quite affordable for most performers;
- cost savings on purchasing rings compared to ready-made plastic containers.
The main disadvantage of concrete sewer systems is the large volume of excavation work, but this property is equally inherent in any external drainage and wastewater treatment systems.
Volumes of septic tanks, dimensions of concrete rings, bottoms and ceilings
The total volume of the septic tank is determined as the three-day water requirement at the rate of 200 liters per person. The filter well is not included in this calculation.
Note! It is believed that the cycle of separation and purification of wastewater is 72 hours.
For a single-chamber septic tank, the entire volume falls on the first chamber; for a two-chamber septic tank, the containers are usually divided in the ratio of 2/3 and 1/3. Although many “simplify” the circuit and make both containers the same, in this case the first of them must be no less than 2/3 of the calculated volume.
Knowing the volume of the septic tank, you can choose the optimal dimensions from the standard range of KS wall rings in accordance with GOST 8020-90.
Typically, sewer rings are selected from the KS15 or KS20 range.
KS7 is used as a well neck (when needed).
KS10 has a volume of 0.24 m3 with a maximum ring height of 89 cm. Three elements of the first tank of a two-chamber septic tank will only be enough for wastewater from the life of one person. They can be used in a two-chamber or three-chamber septic tank scheme as rings for the second and third tanks, if the family consists of no more than three people.
Concrete rings KS can be selected for any septic tank Source rinnipool.ru
Calculation of tank volume
One of the key conditions for the uninterrupted operation of a treatment plant is the correct calculation of its volume.
To correctly calculate the volume of a septic tank, you need to focus on three parameters:
- The number of people who live in the house permanently.
- Total daily volume of sewage waste per person.
- The period of time during which organic substances have time to be completely processed.
When calculating, it is taken as a basis that the average daily volume of wastewater per household is 200 liters. On average, it takes up to three days to process organic substances inside a treatment plant.
When making calculations, it is also worth taking an additional margin of 15-20%. It will allow you to avoid overfilling the norm in case of a temporary increase in the number of household members and guests staying in the house for several days.
So for a family of four people, a structure with a capacity of 200 liters x 3 days will be required. x 4 people = 2.4 cu. m. We round the value and find that for a family of 4 people you need a septic tank with a capacity of 2.5-3 liters.
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.
Soil development
It is recommended to dig one pit, no matter what type of septic tank is chosen. If the septic tank consists of several chambers, then they also dig a common pit, just large enough to accommodate all the planned chambers.
You can dig manually, or you can call specialized equipment. The first option is cheaper. Suitable for those who want to save money. You can dig yourself, or you can hire one or more people to do this work. The second option is quite expensive. But its advantage is that if in the first case it would take at least one day to dig a pit, then here it will take 2-3 hours, no more.
Within the framework of the law, as already written above, a septic tank of any type must necessarily have a concrete base and waterproofing in order to avoid seepage or leakage of fractions and wastewater into the ground. Therefore, the order of work is as follows. The bottom of the cesspool must be compacted. Then a layer of roofing material is laid - this is waterproofing. And a concrete pedestal is poured on top of it.
But the location of the filtration well, on the contrary, does not need to be compacted. There must be free soil here so that the liquid can easily seep down. Part of the soil is replaced with crushed stone, forming a so-called cushion at least half a meter high. The pillow acts as a filter that performs two functions. On the one hand, it allows the water to drain out, and on the other hand, it allows it to freely go into the ground.
At the same time, a trench is being dug for a sewer pipe that runs from the house to the septic tank. The depth of the trench should be greater than the freezing depth in a particular area of the country. If for some reason the trench is dug to a shallower depth, then a heating cable is laid, thanks to which the drains in the pipe will not freeze. It is important to consider that the pipe is laid at a slope of 2 cm per meter of pipe. If the slope is not made, then the drains will not flow freely, which means the entire system will not function. If there is a road above the place where the pipe is laid where cars drive, then the pipe must be placed in a sleeve. The sleeve can be concrete or metal. This measure is necessary to avoid mixing the pipe, since mixing it can lead to damage to the sewerage system.
Installation features
The sewer rings are installed on the bottom slab, which acts as a slab foundation. A prefabricated reinforced concrete structure must have a stable and reliable foundation. Here you also need to prepare the bottom of the pit: leveling, compacting, backfilling with a layer of sand and crushed stone.
During installation, it is necessary to seal the seams with cement mortar, followed by treating the entire surface with waterproofing compounds.
Advice! You can choose rings “with a quarter” - profiled ends. They provide a more reliable connection in terms of joining accuracy, structural strength, and seam tightness.
The recommended height of wells is no more than three rings. If you make it higher, the structure will be “weaker”.
Stage of installation of sewerage in a private house made of concrete rings Source 1beton.info
The entrance hole to the first well is mounted no lower than 30 cm from the lid. And the overflow holes are made with a slight decrease. This leads to a decrease in the “working” volume of the septic tank, which must be taken into account when choosing ring sizes.
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.
Construction options
Most often, one-, two-, or three-level septic tanks are used in suburban areas. In this case, the first septic tank is always sealed. This is where the majority of sewage solids settle.
The remaining wells serve as filter elements. They are not sealed, that is, they do not have a bottom. Secondly, manufacturers today offer perforated concrete rings. Through holes are formed in their walls during the production process.
Single level
This is one well for which filtration fields will need to be built. Or at least a filtration ditch. Not the most effective cleaning option, so it is recommended to construct it from large diameter rings.
Two-level
Ideal for a small country house. Usually the wells are the same size, but this is not necessary. The first one is sealed, the second one is not. They are erected on the same level. But you can lower the second lower than the first.
Three-chamber
From the name it is clear that this is a septic tank of three compartments, which are connected to each other in series, regardless of their location. The arrangement scheme can be as follows: in one line, in the form of the letter “G”, in a triangle.
Typically the first element has a larger volume than the other two individually. Moreover, it is the latter that perform filtration functions. The first is a collection of sewage, where heavy sewage settles.
The process of connecting sewerage tanks into one network
To simplify the process of laying pipes from one container to another, you must immediately order rings that have side holes from the factory specifically for laying pipes through them. Otherwise, you will need to make niches, which complicates the whole process.
The main thing that you should pay special attention to is that the flow from one container to another will occur independently, which means that you need to very carefully make the necessary slopes. So, at the entrance to the first container (or to the chamber, if there is only one), the slope of the pipe should be 2 cm for each meter of its length. For this reason, it is not recommended to build a septic tank far from home, otherwise the depth of the containers will increase significantly, which means additional costs of money, effort and time.
It is important to place the pipes connecting the wells below the level of the entrance to the receiving tank. Otherwise, there will be no natural flow of wastewater from one container to another and the septic tank will not work. The seams are sealed with mortar, treated with waterproofing and sealant.
Ventilation
When installing a septic tank, ventilation is important, one might even say key. It is needed to eliminate unpleasant odors, which, in the absence of ventilation or its improper design, are very unfavorable not only from an aesthetic point of view, but also from a health point of view - breathing methane is harmful, even dangerous in large quantities. Another aspect is that ventilation does not allow the air to discharge. And most importantly, ventilation is needed to keep the entire system in working order.
The sewer drain pipe is connected to a ventilation riser, which should be led to the roof. The diameter of both channels - ventilation and sewer - should have the same diameter, for example, 110 mm (optimally). This will ensure the system functions correctly.
