Septic tanks: types, selection criteria
Operation of a country house is impossible withoutorganization of systems to support appropriate sanitation and hygiene conditions. In this regard, the key place among the engineering and communication systems is sewerage. The waste disposal line can also be arranged without local sewerage, if there is a backbone network near the house. In other cases, it is required to create its own collection and treatment zone, the basis of which is formed by the septic tank and associated communications.
Capacity in the septic system
Septic tanks as such area kind of autonomous sewage system. At the same time, they are responsible not only for draining, but also can clean incoming waste, process it and simply perform a cumulative function.
The simplest models also act asaccumulators, which, as they fill, are emptied by sewer machines. The whole complex is formed only by two main components - a sewage infrastructure with plumbing elements like collectors, pipes and fittings, and a receiver chamber. The latter is the capacity for collection of waste water and household waste.
From the house or other collection points, the targeted productsalong the sewer canal are sent to the septic tanks installed on the site. At the dacha you can do with the simplest designs of a small volume without fine cleaning. However, in a home that is designed for permanent residence, it is recommended to purchase multi-stage filtration devices. They are beneficial not only for economic reasons, but also in terms of simplified maintenance technology. However, the nuances of the operation of containers with different degrees of purification will be considered below.
Classification of tanks
Reservoirs may vary by the same technologypurification of effluents, material of manufacture, volume and design. As for the approach to cleaning, the extreme positions in this segment are taken by simple storage tanks and anaerobic biological water treatment systems.
The material of manufacture is mainly representedplastic, but also metal tanks are used in certain operating conditions. In turn, containers for septic tanks made of polyethylene are considered to be the most profitable solution for domestic use.
The volume of septic tanks can vary - from 150 to 500l on average. There are basically different models for the same dachas (the smallest ones are of the order of 100-150 liters), for cottages and small country houses and for servicing several objects simultaneously.
The construction also determines the possibilities fortank installation - the market offers cubic, cylindrical, rectangular and spherical models. Selecting one or another version of the tank under the septic tank follows, based on the location and method of connection with communications.
The basic solution, which can be called directcontinuation of the concept of a cesspool. The main difference is the complete tightness of the tank, while the pit in accordance with the regulations can be used only in cases where the volume of waste does not exceed 1 m3a day because of the contact of sewage with soilcover. The accumulators of septic tanks do not assume that sewage will have even the slightest contact with the soil, and are intended only for the temporary collection of withdrawal products prior to the arrival of the wastewater.
Mount this tank for a septic tank easierall, since it is the most modest in size, small and undemanding in maintenance. But these benefits are overshadowed by the need for frequent recourse to the aforementioned sanitation services.
Secondary treatment tanks
The container class from which security beginscleaning function. Standard solutions in the middle segment are reservoirs that perform basic filtration and post-treatment. At the first stage, biopreparations are cleaned, as a result of which heavy fractions settle on the bottom of a separate chamber. Emptying of accumulated heavy masses is performed about once every 1-2 years.
As for the liquid, it is already in another chamberis fermented with the use of special bacteria. As a result, clarified filtered water is obtained, but it can not be directly discharged into the ground. The final stage of purification is carried out in a special filtering absorption chamber. At this stage it is important to emphasize the conjugation of the prepared soil zone for cleaning with the capacity of a septic tank for sewerage on the site.
These zones partly serve as a drainagesystem, since water is passed through several layers of crushed stone and sand. In addition, at these levels, cleaning bacteria are again added, thanks to which the so-called soil post-treatment of effluents is carried out.
Tanks for deep cleaning
Deep bio-cleaning provides 100%prepared water for further release into the ground without the risk of a violation of its ecological purity. That is, the need for a regular call of a sewer machine is excluded. But not only is this the advantage of a septic tank with deep cleaning. During the collection and processing of effluents, the reservoir does not spoil the surrounding area with fetid odor, and the silt obtained during filtration can be used for vegetation as a fertilizer. Of course, for such benefits, you have to pay a lot of money when buying, as well as energy costs in the process of exploitation of the septic tank.
Reservoirs with metal housings can becall the traditional solution. Such structures are massive and heavy in comparison with plastic analogs, but they differ in strength. Therefore, they are used exactly where there is a risk of mechanical damage to the tank with adverse consequences during depressurization. At home, metal tanks under the septic can justify themselves in terms of durability. But this operational factor will only take place if the purchase of an inexpensive and resistant to corrosion processes the reservoir.
Containers made of plastic
Most manufacturersengineering and plumbing equipment rely on plastic alloys. At the moment it's not just plastic, but high-strength materials based on polyurethane, fiberglass or polyethylene. They are characterized by lightness, compactness and low cost. In addition, a plastic container for a septic tank is able to withstand low temperatures in severe frosts and not to be corroded in close contact with water.
If we talk about the shortcomings of plasticreservoir, then due to its ease, it is unstable in a stationary installation, therefore, a reliable foundation foundation is required in the course of installation work. Also in the choice should take into account the environmental friendliness of plastic - yet polymer mixtures often include additives with harmful substances.
What else to consider in choosing?
The nature of exploitation should be the basis forchoice. For example, if it is a question of one user who will occasionally come to the dacha, then you can confine yourself to a small-sized single-chamber tank without fine cleaning. For ease of installation, you can buy a septic tank from a metal container that will last long and will not cause problems in maintenance.
And on the contrary, for a resident in the housefamilies are recommended to equip large plastic tanks with the highest possible degree of purification. But in this case, the soil type should also be calculated, since not every soil can have a soil purification effect. In particular, clay cover and areas with high groundwater occurrence are excluded.
Introduces its own corrections in the choice and climate. In cold regions, for example, it is necessary to select the components of a septic tank and communications that have effective thermal insulation or an integrated thermal insulation system.
The installation of the container is realized in several stages,the main of which will be the creation of a trench with a foundation pit. The depth of the pit should not be more than 3 m, and in terms of length and width should be guided by the design of the reservoir. But it is important that around the septic remains about 20 cm for additional padding with cement, crushed stone and sand.
Then the station is put into the preparedpit, the pipes of approach and retraction are mounted. The contours for pipes and branch pipes must pass through trench channels with a slope towards the septic tank, so that the risk of a reverse flow of the drains is excluded. At the final stage, trenches with foundation pit are filled with soil.
Connection of additional communications
If there is a desire to provide more effectivesystem of soil filtration due to separate equipment, this task can be performed in several ways. In particular, it will help to solve the filtering well. It is advisable to use it if the soil composition at the site includes fine gravel, sand and sandy loam. In this case, the well itself should be located 100 cm above the groundwater table.
In such conditions, you can use a septic tankiron container, as it does not require a concrete foundation device, which can interfere with the connection to the well. Another option involves installing an absorbent trench. This drainage pipes with perforations, laid with a depth of 1 m. At the end of such circuits, a ventilation pipe is arranged.
Having planned the organization of the septic tank on the site,it is important to calculate in detail the costs of the project. The fact is that the purchase of capacity alone does not always cover even half of the total cost of installing an autonomous sewer. It is also important to take into account the costs of building materials, additional equipment, electrical accessories, pumps and consumables.
The purchase of a tank can cost 30-200 thousand. rub. For example, the budget plastic capacity for a septic tank for sewer-type storage will just cost 25-30 thousand. The initial segment of models with the post-treatment function offers reservoirs for 40-50 thousand. The most expensive options for home use support the possibility of fine biological cleaning and are available for 100-150 thousand on average.
Again, this is only the cost of the basic design of the septic tank, but as the functionality of the complex expands, additional expensive equipment will be required.