Which septic tank is best for a home: comparison of popular treatment plants

A toilet on the street is not aesthetically pleasing, inconvenient and not environmentally friendly.To solve the problem of creating an independent sewer system to which the entire house can be connected, special containers are installed - septic tanks.

A septic tank is used to collect, purify, settle and clarify wastewater. Wastewater must not be allowed to enter the environment. This is fraught with contamination of the soil, underlying rocks and groundwater.

But which septic tank is best for a home and how to install it correctly? To solve these problems, we will understand the criteria for choosing factory containers for creating an autonomous sewage system. We will also consider the best manufacturers of septic tanks, which will help you choose the best option for your home.

The principle of operation of a septic tank

A septic tank is one of the significant elements of an autonomous sewer system. Its main task is to collect and process wastewater from a house or several buildings. Processing is carried out by simple settling or more complex biological treatment.

Depending on the degree of treatment, wastewater is redirected to an additional treatment facility, discharged into the ground or into a drainage ditch.Multi-stage treatment of wastewater makes it possible to dispose of the clarified and disinfected liquid component without fear of disturbing the natural balance or creating a threatening situation in the environment.

The device may include one or more storage tanks. Its body is made of waterproof materials and has a high level of waterproofing. All types of septic tanks have a receiving chamber or a separate compartment into which wastewater flows by gravity through a sewer pipeline.

The solid insoluble component of the waste mass settles at the bottom. Inclusions of lower density float to the surface, where they are adsorbed by various filtration devices. At this stage, stratification of the wastewater occurs.

The operating principle of the simplest type of septic tank is based on the spontaneous separation of the liquid and solid components of wastewater as a result of settling and flowing from container to container

In a septic tank, there is a continuous process of decomposition of human waste under the influence of a complex of bacteria. They promote the decomposition of organic substances into practically pure water, activated sludge and gases. During processing, all pathogenic microflora are killed.

Next, the purified water is separated from the activated sludge, which accumulates in a settling tank for subsequent pumping by sewer trucks.The clarified and disinfected liquid component moves to the outlet of the septic tank by gravity or using a sewer pump.

A septic tank with biological treatment is an integral multi-level system using biological, mechanical and chemical methods. The wastewater processed by such a septic tank can be disposed of on the surface or undergo additional treatment in an infiltrator for discharge into the ground

For post-treatment and disposal of processed wastewater, the following are used:

• filter fields — are a system of perforated drainage pipes laid in filter trenches filled with sand and gravel mixture;
• absorption/filtration wells — are a sewer well with a filter layer of gravel and sand more than 1 m thick;
• infiltrator — a factory device in the form of a half-tank turned upside down, installed on a ground cushion of gravel and sand;
• sewers and ditches — facilities designed for the accumulation and removal of purified water up to 95-98% to centralized treatment facilities.

If there is a developed central network in the area where an autonomous sewer system with a septic tank is installed, then it is better to connect to it.

Septic tanks purify wastewater by 70 - 75%. To be disposed of in the ground, the liquid coming out of them must undergo ground treatment. For example, in a absorption well

The choice of ground treatment method depends on the degree of wastewater treatment, as well as on the groundwater level and soil type, because:

• for normal disposal of purified water, the soils underlying the post-treatment systems must have sufficient filtration qualities;
• between the conditional bottom of the infiltrator, absorption well and drain of the filtration field there must be at least 1 m;
• In accordance with the requirements of the SES, only wastewater that has undergone biological processing and purified to 95-98% is allowed to be discharged into wastewater bodies and ditches, storm sewers.

Consequently, post-treatment systems can only be installed if the local geological section is dominated by sand, gravel, crushed stone and pebble deposits. There should be at least a meter between the bottom of the structure and the groundwater level in the spring-autumn period.

An autonomous sewage system with a septic tank and infiltrator allows you to discharge the purified and disinfected liquid component of the wastewater directly into the ground

If the conditions of the site where an autonomous sewer system is being built do not meet the listed requirements, it will be necessary to look for a way to connect to the central sewer system.

If the geological section of the site is represented by loose sedimentary deposits (sands, gravel, crushed stone, pebbles) and the highest groundwater level is no more than 3 - 4 m from the surface, then filtration fields are used to discharge wastewater

If this exit is not available, you will have to purchase a biological treatment station, which allows you to drain wastewater into a ditch, or install a storage tank, which does not clean it, but only collects the mass for subsequent pumping by vacuum trucks.

If the geological section on the site is represented by clay soils, septic tanks with a high degree of biological treatment or sealed storage tanks are installed

Comparison of single-chamber septic tanks with multi-chamber ones

Experts recommend using two-camera setups, because...They are able to purify water much better. A single-chamber septic tank is suitable for a home where the total volume of wastewater does not exceed 1 cubic meter per knock and there is no possibility of feces getting into the wastewater.

If you exceed the specified volume and add fecal sewage, then the single-chamber installation will not be able to fully purify the water. The need to call a sewage disposal truck to pump out insoluble sediment will also become more frequent.

The choice of a septic tank that is suitable in volume and quantity depends on the amount of wastewater planned for processing. A single-chamber is installed if the volume does not exceed 1 m³/day, a two-chamber is built when the volume of waste is up to 5-8 m³/day

A more universal solution is multi-dimensional septic tanks. In the first reservoir, most of the inclusions remain in the form of sediment. Through the overflow pipe, the wastewater after primary treatment enters the second chamber.

Here complete biological treatment takes place under the influence of bacteria. All organic inclusions form a solid precipitate that cannot be separated. The gas released during this process is discharged through a ventilation pipe.

The water then flows through the overflow pipe into the infiltration device. In biological treatment stations there are third and fourth chambers in which the final settling of water from sludge is carried out. To enhance the effect of aerobic bacteria, a compressor unit is often supplied to the second and third chambers to saturate the water with the oxygen necessary for the life of aerobes.

Septic tanks that perform biological treatment require power supply, because... Without it, the operation of aerators and compressors is impossible. Structures that purify sewage by settling are, in most cases, energy independent.The exception is schemes in which wastewater is removed using pumps.

A multi-chamber septic tank carries out multi-stage wastewater processing with the participation of anaerobic and aerobic species of bacteria, with oxidation, separation and fermentation of the mass. As a result, at the exit the liquid component is purified to 95 - 98%

To ensure that both chambers have the same pressure, an air channel is created between them. To inspect the septic tank, they are equipped with necks with sealed hatches.

Septic tanks differ from each other:

• volume;
• dimensions;
• productivity;
• set of materials used;
• layout and other features.

Previously, septic tanks were manufactured in-house using reinforced concrete rings. But in such structures it is very difficult to ensure a high degree of sealing due to the large number of joints.

Today, manufacturers of engineering systems offer ready-made solutions made from reliable and sealed materials. Most often, these are several cameras combined within one housing, but there is also a modular design.

Septic tanks for increased cleaning requirements

Sometimes purified water must be used for technical needs. To comply with SES requirements, manufacturers manufacture septic tanks with a biofilter. Aerobic and anaerobic purification is combined with standard mechanical filtration and exfoliation, as well as chemical attack with active oxygen.

Septic tanks with a biofilter are close in their performance to a local treatment plant. The disadvantages of these installations include high cost.

Septic tanks with a biofilter allow you to discharge purified water directly into the ground without harm to nature

Tips for choosing a septic tank

Before purchasing, you need to take into account a number of important nuances that are fundamental to choosing the right model. Next, we will consider the main criteria in more detail.

Subtleties of choosing a place to install a container

Before buying a septic tank, the owner must determine the location of its future installation. In addition, the location of the impressively sized structure must be consistent with a number of sanitary requirements.

Failure to comply with these rules may result in the following consequences:

• penetration of unpleasant odors into the premises of the house;
• release of waste and bacteria into groundwater and water sources;
• contamination of the site as a result of floods, snow melting or rainfall, when the water in the reservoir goes into the ground more slowly, which can create a threat of flooding of the septic tank and subsequent contamination of the surrounding area;

In addition to proper installation of the facility, it is necessary to carry out flawless installation of the pipeline and hermetically sealed pipe connections so that untreated wastewater does not penetrate into the environment without proper treatment.

To protect yourself from all troubles, you must adhere to several regulatory requirements:

1. Consider the location of nearby bodies of water.
2. Consider the location of water intake sources. The septic tank should be located 50 meters from the well, and in case of sandy soil - 80 meters. The distance to a deep well is at least 25 meters.
3. The distance to the foundation is at least 5 meters, and from other outbuildings - more than a meter.

In some cases, the distance to the foundation can be reduced, but this is only in those conditions when a local cleaning station with a biofilter is used. But even this point requires approval.

The location of the septic tank must take into account all nearby objects to comply with sanitary standards

When implementing an autonomous sewerage project, the distance in each case is determined individually, taking into account the characteristics of the soil, landscape and proximity of water sources:

• there should be no trees around the septic tank at a distance of 3 meters (roots can damage the tanks, and the ingress of organic matter can cause the death of plants);
• the structure must be located at least 5 meters from the road;
• the minimum distance to a static reservoir is 30 meters, and to a river or stream - at least 10 meters;
• water supply pipes must be at least 10 meters from the septic tank;
• the distance to your neighbor’s plot should be at least 2 meters.

Compliance with all the requirements may make it somewhat difficult to find a suitable location for a sewerage installation. In addition, it is necessary to think about how a sewage disposal truck will be able to approach in the future to pump out wastewater from the reservoir.

The installation of a septic tank is carried out within the framework of a pre-created project, which is agreed upon with the SES. Construction must be carried out strictly according to the project. Any inconsistencies can give rise to a number of troubles in the form of an administrative offense with unpleasant consequences.

When a sewerage structure is buried below 5 meters in the ground, it will be necessary to obtain permission for its installation from the local municipal organization. It would be good to make a project for an autonomous system in order to accurately calculate costs and plan actions.

The installation of a septic tank buried below 5 m must be fully approved by the local administration

How to choose the volume of a septic tank?

A septic tank of the correct volume will provide a high degree of purification, complete decomposition of organic substances and prevent rapid overflow of the tank. But you shouldn’t go to extremes - an installation that is too large will take up a lot of space, will cost an order of magnitude more and will entail additional labor costs during installation.

You can determine the volume of a septic tank using engineering formulas and special tables, but in order not to confuse anything, you can take a simpler route. According to sanitary standards, wastewater must remain in the septic tank for at least three days.From this it turns out that the volume of the tank should be three times larger than the daily volume of wastewater that the family produces.

It is enough to know how much water is consumed per family member. On average, one adult spends about 200 liters of water every day. But, this indicator may have a different meaning, which depends on the installed plumbing equipment (shower stall, bathtub). It is also worth considering the presence of dishwashers and washing machines, which can cause an increase in daily consumption.

When laying a septic tank, you need to take into account future circumstances, including the arrival of guests or additions to the family. Therefore, it is necessary to purchase an installation with a volume 30% larger than the calculated one. The capacity of the septic tank may decrease due to the accumulation of sediment between scheduled pumpings.

The volume of the septic tank must be calculated for the volley release of wastewater in case of accidents or the arrival of guests

Layout and dimensions of the septic tank

Obviously, the size depends on the volume of the septic tank. Models of various volumes, made in horizontal or vertical form, are available for sale. The choice depends on the available space for installation. The horizontal model will require more space, but for vertical installation it is necessary to dig a deeper pit.

The installation depth depends on the level of seasonal soil freezing, which is determined by the climate zone. This information can be obtained from any construction organization.

If the soil freezes at an impressive depth, it is better to choose a vertically elongated model.The entrance and exit to the structure must be below the freezing level, which means that to install a horizontal structure you will need not only a deep, but also a fairly wide pit.

The main disadvantage of installing bulky, insufficiently filled septic tanks is their floating when the groundwater level rises in the spring-autumn period and during snowmelt. Therefore, they are installed on concrete slabs placed at the bottom of the pit and anchored - attached to the metal ones embedded in the slabs. A vertical septic tank benefits from greater stability, requiring a smaller concrete base.

When installing at a certain depth, you need to take into account the length of the necks through which inspection and pumping of waste is carried out. They should rise 18 - 20 cm above the daytime surface to prevent flooding during snow melting.

If the geological conditions of the site are characterized by high groundwater level and clayey section, storage tanks are used in the sewage system of small private houses

The influence of soil on the choice of septic tank

The equipment of the treatment plant and the method of installing the septic tank depend on the type of soil:

• All types of septic tanks are installed on sand of all types of coarseness and density. Similar bases with excellent filtration properties include gravel and crushed stone soil. The systems can be supplemented with any type of soil post-treatment: a filtration field, a factory infiltrator, an absorption well.
• On clay soils, storage tanks or biological treatment stations are used. Because The filtration qualities of loams, sandy loams, and clays do not allow for disposal into the ground, so pumping methods using vacuum cleaners or dumping into a sewer are used.

If in the underlying section the clayey soil is represented by a layer with a thickness of 1.0–1.5 m, it can be removed and removed, replacing it with a gravel-sand composition. This is the only option when it is not possible to install a bioseptic tank.

If the aquifer on the site lies close to the surface, then in any case only a storage tank is installed.

Case material

All models on the market are divided into metal and polymer. Each of them has disadvantages and advantages.

The simplest models of polymer septic tanks have an affordable price and are not susceptible to floating during floods, because... are equipped with anti-floating ribs. But this also complicates transportation and installation, requiring the use of special equipment.

The metal tank must undergo high-quality factory anti-corrosion treatment and have a high degree of waterproofing. Otherwise, the aggressive environment will simply “eat” the tank.

Experts recommend paying attention to polymer models, as they are more practical and durable.

Another significant disadvantage is the high thermal conductivity of the metal. The drainage in such a tank can simply freeze, even being below the ground freezing level. Therefore, you will have to install a layer of thermal insulation using mineral wool or other material.

Plastic septic tanks are becoming more popular. They are lightweight, reinforced with reinforcing ribs, easy to transport and install, and have a complete design.

These models today are made from three types of materials:

• Polyethylene - the cheapest and lightest, almost completely devoid of seams, which guarantees a high degree of tightness. Limited by maximum wastewater temperatures (hot water can melt the housing).
• Polypropylene – more durable and can withstand abrasive environments and do not wear out. Resistant to any wastewater temperature, suitable for hot wastewater.
• Fiberglass – the most reliable and durable among polymer septic tanks. Fiberglass is resistant to aggressive chemical environments, including organic solvents. Can be used to clean industrial wastewater. They have a higher price.

Polymer septic tanks last 50 years or more. Their only drawback is the likelihood of floating due to their low weight. Therefore, the owner needs to take care of fixing the container in the soil.

Today on the market you can choose a septic tank of any capacity and degree of purification. The volume is selected based on actual water consumption indicators

Review of the most popular septic tank models

The Russian market is dominated by polymer solutions for organizing autonomous sewage systems:

• Series "Tank». The unit with thick polyethylene walls (10-17mm) is designed for 50 years of continuous operation (available in various volumes, meeting the needs of 1 to 10 people). The modular design allows you to assemble several septic tanks into one installation, increasing productivity. Processes a minimum of 600 l/day with a unit weight of 85 kg;
• Biotank series. An autonomous treatment plant, with which recycled water can be directed into the terrain (the design consists of 4 chambers in which biochemical filtration and aeration occurs). Available in sizes that can serve a family from 3 to 10 people.
• Series "Triton T». Increased strength septic tank with a wall thickness of 14-40 mm. It consists of three chambers and has a connector for installing pumping equipment. The model range includes options from 1 to 40 cubic meters, which allows you to serve several houses at the same time.
• Series "Topas». A treatment station that produces deep biological wastewater treatment (for 5-20 people). At the outlet, purified water can be sent for discharge into the ground or into a flow-type reservoir. The septic tank has the ability to remove sludge deposits on its own using a drainage pump or airlift. In this case, it is not necessary to call a sewer truck.

All types of septic tanks require periodic removal of accumulated sludge, which can be used as fertilizer or the basis for forming a compost heap.

If installing a septic tank is impossible due to unsuitable geological and hydrogeological conditions, a storage tank is used in the autonomous sewage system

Rating of septic tank manufacturers

Experts recommend paying attention to the products of the following manufacturers: Evo Stock Bio, FastAlta Bio, Uponor Bio, Purges, Poplar, BIOozone and Tver. The latter are very difficult to install and require the involvement of specialists for installation.

When choosing a septic tank, be sure to take into account the following advice in order to save money. If the house where it is planned to install an autonomous sewer system is used only on weekends or holidays, then it is not necessary to install a full-fledged septic tank.

Bacteria and organic compounds will die due to lack of regular replenishment of the nutrient medium. Therefore, in this case, you can install a simple storage septic tank with the required volume.

But, in this case, you can forget about discharging water into the soil layer. Despite the biological decomposition and sedimentation of wastewater, you will have to call a vacuum cleaner when filling the tank.

Conclusions and useful video on the topic

A video with recommendations for purchasing a septic tank for an autonomous sewage system:

Having your own home is the dream of many people. But you will only be able to feel truly comfortable in it if you create the appropriate conditions.

High-quality water supply and sewerage are critical conditions for comfort if a family regularly lives in the house.

Are you choosing the best septic tank for your home? Maybe you have questions that you would like to discuss, but we have not addressed them in our material? Ask in the comments under this article - we and visitors to our site will try to clarify controversial issues.

Or do you already use a septic tank and want to share your experience with other homeowners? Write your recommendations, add photos, indicate the advantages and disadvantages of your model identified during operation.