Many residents of country houses resort to the construction of a local treatment plant (septic tank) if there are no centralized sewer networks near the site. There are different types of septic tanks, ranging from factory-made products to home-made devices. In our article, we will talk about self-made sewage treatment plants, namely, the device of septic tanks from well rings. Most often, they make a septic tank from concrete rings with their own hands for servicing a summer cottage or a small country house. In our article, we will consider the principle of operation of such structures, their varieties, and the diagram of the device. Videos and photos from the article will help you more clearly understand the process of building a septic tank from reinforced concrete rings.
Device diagram
The diagram of a product from well rings can contain from 1 to 3 chambers made of reinforced concrete products. All chambers are connected to each other by overflow into a single structure. If you do a sewage treatment plant with your own hands, then the scheme of the future design should be developed taking into account the following factors:
- the volume of water consumption in the country or in a country house;
- terrain relief;
- the height of the groundwater table, as well as seasonal changes in this indicator;
- mark of soil freezing in your area;
- availability of free space for the entrance of construction equipment;
- compliance with regulatory gaps from surrounding buildings and wildlife.
Before arranging a septic tank for a summer residence, it is necessary to determine its volume. It depends on the volume of water consumption by residents of the house during the day. The working volume of the treatment plant should be 3 times higher than the norm of water consumption per family. As a rule, it is assumed that 1 person consumes 200 liters of water per day. If this number is multiplied by three and by the number of people living in the house, then you will get the volume of the septic tank.
In such a counting scheme, a septic tank is meant, consisting of two or more chambers. The working volume in this device is determined by the first chamber from the bottom to the overflow pipe.
Important: the actual capacity of the treatment plant may be slightly more than the calculated volume, but in no case less.
Principle of operation
In a wastewater treatment plant, consisting of one chamber, a cumulative work scheme is used. Moreover, the larger the chamber, the less often the sludge will have to be pumped out.
In septic tanks, consisting of two or more chambers, the principle of operation is based on the separation of wastewater into different fractions. The solid components of the effluent are deposited at the bottom under the action of gravitational forces. Clarified water remains in the upper part of the effluent. This principle contributes to the fact that pre-treated wastewater is supplied to the second chamber.
In the second chamber of the reinforced concrete rings, the drains are again settled. As a result, this cleaning principle contributes to the fact that water completely purified from solid impurities gets into the third chamber. The scheme of operation of the third chamber resembles a filter well, where pre-treated wastewater through an interlayer of filtration material goes into the ground.
Varieties
Making a septic tank from concrete rings with your own hands is quite simple, but first you need to decide how many chambers will be in your structure. You can make the following suburban septic tank from concrete goods:
- Single chamber product Is a reservoir for collecting sewage. A correct single-chamber septic tank should have a multiple of the daily discharge value. The design can be carried out without a bottom. A single-chamber installation scheme does not imply a drainage layer at the bottom of a structure made of reinforced concrete rings. The effluent is purified by soil filtration. As the soil becomes silted with heavy fractions, the efficiency of the treatment plant decreases.
Important: sewage should not seep through the joints of the well rings in a single-chamber septic tank.
- Two-chamber cleaning product... The device, consisting of two cameras, is more functional. In the first compartment-settling tank, heavy components of effluents settle to the bottom, and pre-purified settled water enters the second chamber. In this compartment, a drainage layer of sand and gravel is arranged at the bottom, through which the waters go into the ground. A septic tank with two chambers has the following operating state: the first chamber is always filled to the overflow level, the volume of effluent in the second chamber depends on the filtration rate and the volume of discharge.
Attention: the bottom of the filter well should not be built on clay soil, which has poor permeability. Construction is best done on sandy soils.
- Three-chamber septic tank made of reinforced concrete rings - the most perfect device from the point of view of the correct disposal of waste. The first two wells are sedimentation tanks where mechanical wastewater treatment is performed. The third compartment is a filter well. Such a septic tank for a summer residence has the following operating condition: the first two chambers are filled before overflow, and in the third compartment there is a small amount of water.
The construction of septic tanks without a bottom is allowed in two cases:
- With a low location of groundwater. In this case, the likelihood of runoff entering the aquifers is completely excluded.
- If it is required to provide water filtration into the ground. In this case, a sand and gravel filtration layer is installed at the bottom of the structure.
To significantly speed up the process of decomposition of organic waste, you can build a septic tank with aeration. For this, a special device is used - a compressor with a timer, which injects air into the second chamber under pressure. As a result, the activity of aerobic microorganisms is activated, which decompose ammonia into nitrites.
Wastewater treatment plant without pumping
This name of the treatment plant is rather arbitrary and does not mean that the sludge does not need to be pumped out of the septic tank at all. However, with the right device, you will have to do this much less often. For example, such structures are known in the country, from which the sediment has not been pumped out for 10 years in a row.
In fact, this is a three-chamber structure, where in the first compartment, solid waste is processed by anaerobic bacteria without air access. Here the solid components are decomposed by microorganisms into hydrogen sulphide and methane, so a small muddy sediment is formed. The better the decomposition process is performed, the less sediment is formed at the bottom.
For the efficiency of such a septic tank, you will need to equip the aeration of the second chamber with your own hands. Here, aerobic microorganisms will process the organic constituents of the effluent. They need oxygen for their vital functions, so a compressor is needed.
In the third chamber of such a unit in the country, it is necessary to equip a high-quality filter at the bottom so that the final filtration of pre-treated wastewater takes place. As a result, a minimum of sediment will form, and you will not need pumping soon.
Choosing a place for a septic tank
The place for the treatment plant is selected in compliance with the following rules:
- From the septic tank to the well or well, there must be at least 30 m.
- On the terrain, the cleaning product is installed lower down the slope than other buildings.
- It is worth retreating at least 5 m from the foundation of a residential building to the treatment plant.
- From open reservoirs to a septic tank should be at least 10-15 m.
It is also worth remembering that the sewer pipeline is laid with a slope from the house to the septic tank. At the same time, for each meter of length, the slope is 2 cm.The trench for the pipeline is dug at a depth of 0.9-1 m.
Mounting
The video at the end of the article clearly shows the septic tank device. If you decide to make a sewage treatment plant from reinforced concrete products with your own hands, then its construction is carried out in the following sequence:
- A pit for a septic tank can be dug with a shovel or using construction equipment. In this case, the dimensions of the pit should slightly (by 20 cm) exceed the dimensions of the rings.
- Now you need to prepare the base at the bottom of the pit for the concrete rings. You can lay a factory-made concrete slab or make a base of in-situ concrete. For this, a reinforcing mesh with cells of 20x20 cm is knitted, laid on the bottom and poured with concrete with a layer of at least 20 cm. Moreover, the concrete base can be made under each of the wells or be common for all chambers.
- Now reinforced concrete elements are installed on the prepared base. After the construction of the well, holes for the pipeline and tees are marked and punched in its walls. To do this, you can use a grinder and a hammer drill.
- Further, connecting pipelines are installed between the wells and a drain pipe is connected.
- We carry out waterproofing of concrete rings. For these purposes, the outer surface must be coated with liquid polymer mastics, bitumen composition or liquid glass. Also, for these purposes, you can use a special concrete mixture with additives, which will make the rings waterproof. Seams between the elements are filled with special care.
- We install the covers over the cameras. In this case, the covers above the first and second sedimentation tank must have hatches for removing sediment.
- Now we are building ventilation. To do this, in the lid above the second chamber, we install a ventilation pipe that rises 50 cm above the ground.
- Backfilling can be done at this stage. The soil is filled up between the walls of the pit and the structure and rammed every 20-30 cm. The cover is covered with soil so that the hatch is on the surface.
Maintenance of a treatment plant made of reinforced concrete rings is reduced to monitoring the level of waste liquid in all chambers. Clean them if necessary.
Video about the device of a two-chamber treatment plant made of concrete rings:
