It is convenient when a private house is connected to a centralized sewerage system. But if this is not possible, then you should think about installing a local waste disposal system — a septic tank.
It allows you to save the site from pollution, and in some cases it makes it possible to obtain process water from wastewater for watering plants, washing cars, etc.
At the same time, the operation of the septic tank is based on a simple principle.
How does a septic tank work?
Whatever the cleaning device, its operation is based on 3 principles:
- sedimentation of large suspensions;
- floatation of light pollutants;
- biological decomposition.
All septic tanks consist of several chambers. The first 2 stages of cleaning take place in the first tank. The branch pipe leading to the next chamber is located in the center, draining water, in which there are no longer suspended suspensions and heavy fractions. The type of biodegradation and its effectiveness depends on the type of apparatus.
On the video you can see the process of water purification in a septic tank:
Types of septic tanks for a private house
The classification of the wastewater treatment system into types is based on the dependence on electricity, the type of biodegradation and the material from which the septic tank is made.
Anaerobic and aerobic varieties
In simpler designs, anaerobic (oxygen-free) decomposition of contaminants occurs in the second and subsequent tanks. Such cleaning is not complete and requires an additional stage of soil filtration: filtration wells or filtration fields.
In them, the remaining contaminants are retained by the filtering backfill, on which a film of microorganisms is additionally formed, continuing the process of biooxidation.
Local treatment plants more complex and efficient designs. They mimic large sewer effluent treatment systems.
There are also several cameras in the LOS. In addition to settling and anaerobic decomposition, such a device has a compartment in which aerobic microorganisms (activated sludge) break down pollution in the presence of oxygen.
After that, the water enters a special sump for the settling of activated sludge, which is pumped out by the airlift into the stabilization compartment. Part of the sludge mass is again fed into the aerobic treatment tank. Precipitated dense sludge must be periodically removed from the tank.
There are also storage tanks in which water does not undergo any treatment other than precipitation. They only collect and periodically remove wastewater. Accumulators can only conditionally be called a septic tank, this is a cesspool — a cheap option to install, suitable only for small country houses with a small amount of drains.
Dependence on electricity
It is important to know this principle of classification of waste disposal systems, since not all country houses have access to an uninterrupted supply of electricity.
- non-volatile are simple devices where anaerobic oxidation of organic matter is carried out, and water is poured between reservoirs and to the stage of soil post-treatment by gravity.
- VOCs do not work without electricitynecessary for the operation of the compressor supplying air. Also, in many models, wastewater from one chamber to another and activated sludge are pumped by airlifts powered by a compressor.
Anaerobic devices depend on electricity when, due to the nature of the landscape, it is necessary to install a pump to transfer liquid to the soil filtration stage.
What and how to make a septic tank?
Waste treatment tanks can be made from a variety of materials.
- There is finished plastic tanks. You can also make them yourself from several large-diameter plastic pipes or eurocubes. Mounting such containers is quick and easy, without the involvement of special equipment. They are durable and have become very popular lately.
- metal containers may be ready. They can also be welded from several sheets. Such tanks are rarely used, mainly when it is necessary to place the container at a great depth. From the inside, to extend the life of the container, it is recommended to treat it with an anti-corrosion compound.
- brick — budgetary, but physically expensive material. The brick is laid on a concrete base. The cross section can be round and with right angles.
- Septic tanks from concrete rings — one of the most traditional options. Products with a diameter of about 1 m are used, which are installed on top of each other. For their delivery and installation, it is necessary to hire a truck and a crane. Concrete containers often leak at the junction.
Budget, but not very reliable tanks are made of wood, tires from truck wheels.
When choosing the type and model of the device, it is necessary to correctly make calculations, take into account the features of the site.
An important factor is the price of the finished station.
How to choose a septic tank for a private house?
The simplest and most reliable option is a ready-made plastic septic tank. There are enough companies offering such products now. Before buying or self-constructing a septic tank for a toilet, you need to decide on several parameters.
The required capacity and volume are determined by the number of inhabitants. If guests will periodically live in the house, then they must also be taken into account in the calculations. On average, one person generates 200 liters of wastewater per day.
For a family of four, equipment with a capacity of 800 liters is required. Since wastewater can be in the tanks for 3 days, then power received must be multiplied by 3to get the volume value. For our example, we need tank with a volume of 2.4 m3.
Features of the relief, soil and climatic conditions are also important not only at the installation stage, but also at the purchase stage.
- You need to know the depth of soil freezing, because the pipeline and its entrance to the tank must be below the zero point. There are special ready-made models with an elongated neck and a low inlet.
- Samo equipment is recommended to be installed where there is an elevation to protect against atmospheric moisture.
- If the landscape does not allow gravity to remove effluent from the reservoirthen you need to choose a model with forced evacuation of the purified liquid, in the last chamber of which the pump is located.
- For clay soils prone to bursting during freezing we need structures with especially strong walls: concrete, plastic with stiffeners.
- For soil post-treatment, it is especially important to know the type of soil. The best option is sandy soil. In other cases, the arrangement of filtration fields requires a lot of effort.
Cost and popular models
Each owner takes into account the price of the waste disposal device. But here it is better not to save.
The best option is to purchase ready-made equipment.
Below are prices for popular models designed to serve 4–5 people.
- Popular septic tank with soil aftertreatment Tank 2.5 in full set from 360 $.
- Proven Poplar 5related to complete biological treatment plants, can be purchased at least 720$.
- Topas 5 also provides a high degree of wastewater treatment. The cost of such equipment about 800 dollars.
- If you are looking for a septic tank for a summer residence, then a good option could be “Triton-mini”, with a volume of 750 liters. Together with the soil filtration system, it costs about 220 $.
- More and more positive reviews are gaining and LOS “Unilos Astra‑5”. You can become the owner of this system for about 800 $.
Many users have already seen the reliable operation of these devices. In addition, they are all simple and for self-assembly.
Device and installation of septic tanks
Installing a wastewater treatment device is quite simple, especially a ready-made plastic container, to which instructions are attached. First you need to choose the right place.
- From the foundation the house to the septic tank must be at least 5 meters. But you don’t need to install too far, otherwise you need a revision well.
- Distance between trees and a septic tank 3 m.
- From rivers and reservoirs to the wastewater treatment device should be 30 m, and from wells and wells — 50 m.
- Roads should not pass over the filtration fields.
As mentioned above, it is important to know the depth of soil freezing, which is indicated in SNIP 2.02.01–83 * for each region of the country. Pipes and soil filtration elements must be located below the zero temperature point.
Based on all these data, a septic tank is installed in accordance with with step by step instructions.
- They dig trenches under a slope for pipes and a foundation pit for the septic tank itself.
- A layer of sand 10 mm thick is poured into the ravines, it is rammed, always observing the slope.
- Construct a sand and, if necessary, a concrete cushion in the pit. It must be even.
- Install a septic tank exactly.
- Connect it to the supply pipes, as well as a pipeline leading to soil filtration or a collection tank.
- Fall asleep pipes and tank. It is important to pour liquid into the container, the water level should be 150 mm above the backfill level.
Sprinkle the tank with a mixture of cement and sand, and the last 30 cm with soil. After that, the system is ready for start-up and operation.
Watch a video on how to make a septic tank with your own hands:
Septic tank maintenance: price
Plastic tanks do not require special care.
- Once a quarter, the VOC evaluates the sludge. If it is dark and begins to thicken, then it must be removed. To do this, you can use a simple drainage pump.
- Once every 1–2 years, it is necessary to pump out the sediment from the sump using a sewage machine. At this time, it is recommended to flush the entire tank.
- Once a week it is worth looking into the hatch of the tank to evaluate the work. This is especially true for aerobic installations.
You can conclude an agreement with a specialized organization for maintenance. A one-time procedure with sludge pumping and equipment revision costs at least 40 dollars. The minimum cost of annual maintenance is 150 $.
The full range of works and the price for them depends on the model.
Which is better: model characteristics
|Price, thousand rubles
*for VOCs, the volumes of salvo release are indicated.
If you decide to install a septic tank inexpensively, i.e. independently and chose a ready-made plastic model, the cost of the finished structure will depend on the price of the model, sand, cement and pipelines.
You can order the installation of a turnkey cleaning system. The minimum cost of such a service is 210 $.
But having invested once, you will ensure the reliable operation of the treatment equipment and the cleanliness of the site itself.