Septic tank in high groundwater conditions. About a concrete septic tank with a high ugv

GWL (groundwater level) determines how close to the surface the subsoil water approaches. It is good if it goes below the bottom of the septic tank.

But what if the liquid is located at a depth of only 0.5-1m? What is the danger and how to solve the problem? A septic tank with a high level of groundwater will serve for many years if installed correctly.

The first thing to do is to identify the GWL and understand the magnitude of the problem.

Important: the liquid is as close to the surface as possible in spring and autumn. In the first case, the reason is the melting of snow, in the second - prolonged rains.

Here are 5 ways to define it:

The easiest way is to ask the locals. Perhaps the neighbors already know at what depth the groundwater level is located or they have a well on the site.
Flora as a guide. Certain plant species can only survive when the water comes close enough to the surface. The following table will help you navigate:
Inspection of the site. If there are wetlands, it means that the groundwater level is located close to the surface or the soil is too clayey. And also inspect the area adjacent to the site.
The grandfather's way. To do this, you need a clay pot, a clump of wool, defatted with white spirit and an ordinary chicken egg. A small layer of turf is removed with a shovel in the place where the septic tank will be located. Put wool, on top - an egg and cover with a pot. An examination is carried out in the morning. If water droplets are clearly visible on the egg, the groundwater level is close to the surface.
Drilling holes at several points in a suburban area. This method is rather laborious. But it is 100% reliable. Step-by-step instruction:

Find a good, long drill - at least two meters - and a straight pole, on which you mark every 100 mm.
Identify drilling points on the site. It is not necessary to drill a well only in the intended location of the sump. It is possible that it will need to be relocated, so select multiple points throughout the site.
Drill wells. Place a waterproof material on top to prevent precipitation from entering the shaft. Wait 24 hours.
Using the prepared pole, determine the GWL: immerse it in the well, reaching the bottom, pull out and subtract the length of the wet part from the depth of the mine.

Folk omens also help a lot. This is especially true in summer, when drilling cannot guarantee 100% measurement accuracy. The fact is that in the heat, the liquid drains into the nearest reservoirs and the level sometimes drops - very significantly.

Potential flooding sites will help identify midges that sense the proximity of moisture and will swarm exactly in this place. You can also navigate by the abundance of dew in the morning and the density of fog in the evening. The more clearly these signs appear, the closer the liquid is to the surface. Obviously, when constructing any underground structures, it is advisable to avoid such places.

A similar situation with a drop in the liquid level is observed in the middle of winter. Only the reason is not in the drainage of water, but in the freezing of the upper layer of the soil during severe frosts. Measurements taken during this period can be easily misleading. In case of heavy precipitation, the liquid mark in spring can increase by 2–3 times.

Important: if possible, the determination of the GWL should be carried out several times a year and the smallest value should be taken for calculations.

What problems can there be

The device of a septic tank with a groundwater level closer than two meters from the surface requires additional measures.

Problems arising during the installation of a sedimentation tank in a section with a VUHV can be divided into several groups:

1) When installing. First of all, this increases the complexity of the work. Digging a foundation pit in liquid mud is not very comfortable. We'll have to use a pump for pumping out and arrange drainage on the site. Step-by-step instruction:

deepen the pit as much as possible in one place;
organize a drain;
install a vibration pump (motor pump);
when liquid accumulates in a depression, pump it out;
while the pump is running, make sure that the hose does not burrow into the ground (the pump may clog);
in the meantime, excavate the soil with a slope towards the excavation, which must also deepen accordingly.

After the pit has been dug, it is necessary to protect the walls from collapse. For this, wooden or metal dowels are hammered. During the installation of the sump, water is also collected in the recess and removed using a motor pump.

Important: it is much easier to correctly determine the level and take action in time than to deal with the consequences later.

2) Damage. As a result of excessive pressure of subsoil waters, the soil swells, and the container can be easily damaged. Sewer runoff, mixed with underground water veins, can enter the drinking well or come to the surface with the remains of faeces. This situation can provoke infection with dangerous infections, not to mention an unpleasant odor throughout the entire area.

To avoid such sad consequences, it is enough to choose the right material for the purifier. Ideally, this should be a sealed container buried in the ground. Experts recommend using modern, high-strength plastic.

But it is also important to correctly backfill the pit after installing the sump.

The filling is carried out with a special composition: you need to mix 5 parts of dry sand with 1 part of cement. Layer thickness 100–150 mm. and each must be spilled with water and carefully sealed.

You will have to dig out the container, if the septic tank with high groundwater was nevertheless installed incorrectly and damaged, pump out the contents and find cracks. If the damage is minor, a seal can be performed.

For this, special sealants are used. In especially difficult cases, you will need to apply a patch using a special plastic welding machine. In case of significant damage, the container will have to be replaced.

Important: damage to the case can be indirectly diagnosed when an unpleasant odor appears and soil siltation at the installation site.

3) The plastic sump may float. To avoid this problem, a reinforced concrete anchor-base is provided at the bottom of the pit (this can be a factory one), to which a septic tank is attached. There is no other way to cope: the container will simply float up.

In case of problems with access of lifting equipment to the place of work, the slab is poured directly into the pit. In the body of concrete, mortgages are left, to which the tank is attached with metal clamps. Additionally, a layer of sand, 10 cm thick, is poured onto the bottom of the container. Such a structure will reliably hold it and prevent it from floating.

The ascent has already occurred. Step-by-step instruction:

inspect the sump and make sure that it is not damaged - the container must be airtight;
use a pump to pump out the contents (it is advisable to immediately call a sewage truck), in case of damage, perform the necessary repairs;
wash the sump;
completely remove it from the pit;
mount correctly (see above).

4) Flooding . Overfilling can be caused by many reasons. And groundwater is only one of them. First of all, it is worth forcibly pumping out all the contents, checking the operation of electrical equipment, the correct connection of hoses and infiltrates.
If, nevertheless, the reason is in excess groundwater, especially if the level is unstable, it is necessary to organize the pumping of liquid by a forced method. For this, you can use another pump installed in the immediate vicinity of the outlet.

If this method does not help, you will have to use a pipe to divert clean water further, to an area with dry soil. There it can easily be absorbed into the soil, and the sump will not overflow.

To avoid such difficulties, it is better to provide a drainage system for the removal of groundwater in advance, even before the installation of a septic tank.

5) Waterlogging. With a high groundwater level, there is often a problem with the final treatment of wastewater. The soil already has high humidity. The extra moisture simply won't be absorbed. Gradually, the place around the tank will turn into a swamp. To solve the problem, you need to mount a filtering field. Simply put, an artificial embankment, which is arranged in a previously dug pit - to the required level and is filled with rubble and sand 1.5–1.8 m above the ground.

The step-by-step diagram of the device of such a field is as follows:

The necessary calculations are carried out. On average, 1 person drains 200 l / day into a septic tank (established empirically). The filtration coefficient is determined in accordance with GOST 23278 “Soils. Permeability Field Test Methods "by pouring water into pits. Based on the tests, we determine the steady flow. Let's say it was 4 l / h. Pit dimensions: diameter 250 mm, depth - 100 mm. From here we define the wetted area: bottom - 3.14 * 0.125 2 = 0.05 m 2; walls - 3.14 * 0.25 * 0.1 = 0.1 m 2, S total. = 0.05 + 0.1 = 0.15 m 2. From here, through 1 m 2 per day, 0.15 / 1 * 4 * 24 = 640 l / day will be filtered. Based on these data, we take the required field area.
A pit is being developed (always dry).
Make a pillow from 500 mm thick crushed stone.
Pour 1 m of sand.
Laying drains (perforated plastic pipes). This design will provide an even distribution of fluid on the field. The length of the pipes should not exceed 20 m. The distance between the drains is no more than 1.5 m. The supply of pre-treated water to the field is provided by a pump. When laying, pipes are protected with geotextiles. Each drain is equipped with a ventilation riser, which must be 0.5 m above the ground.
Place the filter cloth.
Backfilling is carried out.

6) Drainage. Sump drainage can be carried out using a filter well.
Instead of a concrete well, you can use a plastic container without a bottom, the installation of which is much easier. Coarse sand is poured onto the bottom, then fine gravel or crushed stone. The thickness of the layers is 200 mm. To exclude the impact on the well, it is sprinkled with expanded clay from the outside.

Requirements for a treatment plant with a high ground water level

The housing is made of durable plastic and must be sealed.
The structure should have a low height.
The volume of the tank should correspond to the daily flow rate multiplied by three.
Septic tanks intended for high ground water must be securely anchored to a concrete base.

The following types of septic tanks are ideal for the drainage of sewage during VUHV:

Sealed storage tank. The most commonly used prefabricated plastic construction. It is guaranteed not to leak and can have a volume of up to 300 liters. Such a system is good in a country house or in a small private house, if the owners live there periodically. But she will not solve the problems with the permanent residence of a large family. The main disadvantage of this design of a septic tank is the regular pumping out of sewage.
Three-section anaerobic device. The first compartment (sump) serves to separate the waste into fractions as a result of the separation of fats and the precipitation of solid parts. In the last two, preliminary wastewater treatment takes place. The supply of waste from one compartment to another is provided by an overflow pump. It is impossible to dump waste without additional filtration through the soil, since this leads to a violation of sanitary standards.
VOC (local cleaning station)... Waste goes through a full cycle of biological treatment. With the help of bacteria, the effluent is broken down into sludge and water. Such devices are quite expensive, but the costs are worth it, if you equip such a system on the site, then you can forget about pumping out the sewage system for many years.

Required tools and materials

Below we will consider in more detail the process of installing a storage tank. For self-installation, you will need the following tools:

motor pump;
shovels;
metal cable;
building level;
jigsaw.

You need to prepare the following materials:

wooden or metal tongue;
formwork boards, reinforcement AIII Ø12 mm, concrete B12.5 (with a monolithic foundation) or prefabricated reinforced concrete slab;
clamps for attaching the container to the base;
sealant.

DIY installation and work plan

Sump installation consists of the following steps:

Development of a pit and a forced drainage device (details are discussed in more detail above).
The pit slopes are fastened to ensure safety and protection from collapse. During the work, there should be no liquid in the pit. It is pumped out using a motor pump. But overnight it is recruited. This can cause the walls to collapse if they are not secured.
Installation of a concrete slab or concreting of the base. The process is as follows:

The bottom of the pit is leveled using a building level for control.
Then arrange a sand bed with a thickness of 150 mm. The sand is spilled with water and carefully compacted.
The next layer is waterproofing. Experts recommend using two layers of roofing material.
Formwork and reinforcement cage are installed on the waterproofing, concrete is poured. It should be laid in even layers, vibrating. It is advisable not to stop work for more than 4 hours. If the conditions allow the passage of equipment, you can use a ready-made reinforced concrete slab, which will significantly reduce labor intensity. With a monolithic structure, mortgages must be left in the concrete body for fastening the tank.
We install a ready-made plastic container on the prepared base, having previously calculated the required volume and checking its tightness. With special clamps we attach the tank to the embedded parts of the "foundation" by welding or bolts. Now there is no need to be afraid that it will emerge.
We connect the supply pipe, carefully seal all joints and insulate the septic tank and all pipelines.
We carry out backfilling with protection against heaving of the soil as a result of a drop in groundwater level (a mixture of sand and cement with a layer-by-layer spill and compaction).

Important:

Around the container should be covered with a layer of expanded clay with a thickness of at least 200 mm. This will prevent freezing and reduce the negative impact of external factors.
During filling, it is necessary to gradually fill the container with liquid so that the water level is always above the filled level. In this way, you can protect the septic tank from damage.

Operation in VUHV conditions, as well as installation, requires special measures:

It is forbidden to clog the system with large debris. This will lead to clogging.
The sewer pipe and sump must be carefully insulated.
You need to pump out the drains regularly. Do not allow the tank to be more than 2/3 full.
When used as a natural filter, it is worth remembering that any chemistry will kill them.

Compliance with these simple rules will make the operation of the sewer system easy and save you from unnecessary problems and an unpleasant smell.

Autonomous - the only way out at high ground level.

Useful video

In detail and step by step:

Installation of concrete:

Hello, friends.
I want to touch upon such, I am not afraid of this word, a burning topic, like a self-made concrete with a high GWL.
Of course, we all want to save money, and not buy Topas and Yubasy for crazy loot. But at the same time, we want the blood money buried in the ground not to be lost in vain, that is, to work, cleanse, and not spread aromas.
There are a number of problems with concrete septic tanks with a high GWL:
1. It is difficult to concrete the bottom, often people do not care about it, and bury the first well without a bottom. Then, for some reason, a drainage is made from this well in the filtration field, although a well without a bottom in itself is already a filtration well.
2. Difficult to seal rings. It is not even so important that the concrete will let the waste water go outside, passing through the concrete they will be cleared better than even reaching the last well. Worse, groundwater can get inside and change the level of fluids in the chambers. For example, if the water in the second chamber rises above the overflow with the first chamber, then the liquid in the two chambers will mix and will be of the same degree of purity. The same is with the third chamber, and it turns out a single-chamber septic tank with a large, cleverly shaped chamber. The degree of purification is zero.
3. And most importantly, for soil filtration, you cannot make a third well. It is necessary to make a mound, for the same reason. So that the water does not go back into the septic tank, and does not make senseless the presence of 3 chambers of sedimentation tanks, mixing everything together, as well as blocking the ventilation holes, and making the septic tank smell fragrant. So an extra pile on the site is inevitable.
Save up for Topas? In no case!
You can save money by making two sealed chambers and overflowing into a third through a pump and check valves!
But, in order.
1. To begin with, I would not use rings, but would fill everything myself. I would fill in the monolith, it, in my opinion, is easier to seal, now there are a lot of all kinds of additives and means for waterproofing concrete, and there will be no problems with displacement of the rings. Again, it is easier to dig a hole, and most importantly, you can avoid flooding the hole with groundwater.
To do this, next to the main pit, an auxiliary, small one is digging, the pits must be communicated. The small hole should be deeper. The bottom of the main pit should be with a slope towards the small one; gravel must be poured onto the bottom of the main pit so that all the water flows down the gravel into the small pit. And into this smallest hole we throw a pump for dirty water, which turns on by the float, and that's all, you can fill it. Now the main pit will always be dry.
2. We put the formwork, fill in two sealed chambers, and one without a bottom. Between the first two chambers, the communication will be absolutely standard, pipes, tees ... But between the second and third chambers, we cut a check valve into the wall. There is no particular hope for gravity, so we hang a pump with a float from a small pit in the second chamber (waste-free production), so that it turns on at the moment when the liquid does not reach the overflow level between the first and second chambers of 5 cm.
Thus, we get the first two chambers from the bottom, sealed, in which each chamber works normally in its function, thanks to the correct levels of liquids, and a filtration well, in which the water level does not affect the operation of the first two chambers, even if it is below the surface. Also, there are no heaps.
I want to start as soon as I go on vacation, i.e. since Saturday.
Well, what do you think will work out, or is it time to go and give up?

For the equipment of the sewerage system in country houses where it is not possible to connect to a centralized system, it is necessary to install local treatment facilities or a septic tank. The second option is the most profitable from a financial point of view, so many people make a choice in its favor. However, during installation, you can face one serious problem - a high level of groundwater (GWL). As a result, a logical question arises - how to make a septic tank if the groundwater is close?

Installation of a septic tank on the site

Why is it important to consider the GWL?

If the water is near the surface of the earth, this means that when deepening the septic tank, it will be necessary to use special construction methods aimed at ensuring the stability of the structure and preventing depressurization of the joints. In winter, another danger arises - freezing of the soil and, as a result, the occurrence of heaving, which can cause deformation of the drive. That is, the runoff will fall into the ground and then into the water layer and pollute the environment, which is unacceptable.
During spring floods, reservoirs can flood the nearest territory and a septic tank can float up. The result is the same as in the previous version, only the sewage will still pollute the reservoir. It can also rip apart plastic sewer pipes and have to be replaced. In the worst case, the septic tank will remain in the ground, and water will flood it from above, as a result of which the sewage will go back to the house in the absence of a check valve installed.
It is unacceptable to use septic tanks with leaking structures. This is especially true for the use of cesspools or septic tanks in the form of concrete rings. Firstly, its construction will require financial costs comparable to a sealed septic tank made in an industrial environment, and secondly, it contradicts sanitary standards.
Depending on the groundwater level, it is necessary to apply special constructive measures to ensure maximum protection to prevent an environmental disaster.

How to accurately determine the GWL?

Usually, measurements are taken in the spring, when the water rises to the maximum possible height after the snow melts. They take an ordinary garden drill, make a vertical hole in the ground to the surface of the water, and then determine their depth. If the septic tank needs to be installed promptly, then you can use the data of geological exploration, which will reliably show how the water layer passes under the land plot. Another less informative way is to get the necessary information from the old-timers, but it is not always worth trusting.

preparation of pits for installing a septic tank

Is it worth making a septic tank yourself?

Despite the seeming simplicity of the septic tank design, design work on its calculation, selection of strength and performance characteristics is a task for professionals. However, their cost is several times more expensive than homemade ones. The difference in them will be significant and consist in the following:

The finished structure will provide maximum tightness due to the fitting of all parts and the use of stiffening ribs, which can prevent any loads within the specification. It will be very difficult to evaluate the assessment of a home-made system, so it is not known how it will behave in a specific situation.
An industrial septic tank is equipped with all the necessary filters, is able to cope with specific loads and meet sanitary standards.
Ready-made septic tanks have not only a high level of protection from external mechanical, but also from internal chemical influences, while ensuring stable operation during the warranty period. A self-made design cannot guarantee that there are no leaks into the ground or a sufficient degree of cleaning when using filtration fields.

Therefore, before deciding on choosing a septic tank of a ready-made design or laying your own, you need to weigh everything and make the only correct decision.

installation of a concrete septic tank from rings

In the absence of the necessary experience, it is worth contacting a specialist who can analyze the soil or already available data and select the most suitable structure in terms of parameters.

What requirements should a septic tank meet?

have complete sealing of the chambers;
have protection against surfacing;
have a high strength of the case.

What device should a septic tank have with a high GWL?

The design of the septic tank must be airtight and consist of one container, divided into compartments, or several eurocubes. The system can be either gravity or forced injection. The second option should be used only in cases where the installation is carried out on a heated area and it became necessary to place storage tanks above the level of the house.

A non-return valve must be installed on the inlet pipe to prevent waste water from flowing back. The pipe for the outlet of treated water should be made at such a level that ground water does not get there. Usually, a special sealed compartment or a separate sealed container is provided for this.

Rules for choosing a septic tank with a high GWL

The volume of the septic tank must be clearly calculated so that at high loads it does not have to constantly remove sewage.
The type of construction is allowed either accumulative or with pumping of purified water and its effective drainage into the ground.
It is advisable to choose the material of the septic tank on the basis of durable plastic and steel with a protective polymer coating. It is not recommended to use a concrete septic tank with a high level of groundwater, since the soil can freeze and there is a high probability of displacement of one ring relative to the second and the ingress of sewage into the soil is simply inevitable. An exception may be soils with a dense composition and a minimum level of heaving.
In order to increase the cleaning performance and minimize the amount of sewage removal, a multi-stage cleaning system should be organized: from mechanical impurities, chemical disinfection and filtration of purified water with discharge into the ground.

septic tank system trenches

How to choose a place to install a septic tank?

The installation site must first of all meet sanitary standards:

The distance from the residential building must be at least 5 m.
From sources of drinking water, the distance should be from 50 m, and from open reservoirs - 30 m.

In this case, it is necessary to take into account the location of buildings so that they are at a distance convenient for servicing the septic tank. Also, do not forget that the sewer pipe must be inclined. The greater the distance from the sewage discharge points, the more depth will be required based on the condition of an inclination of 2-3 degrees per meter of length, while in the presence of a minimum GWL of up to 1 m, this is simply unacceptable.

When creating sealed containers for wastewater disposal, it will be necessary to organize a convenient access for vehicles for pumping them out.

How to properly install a septic tank?

A septic tank for a high level of groundwater should not only be installed on a stable base, but also be firmly fixed to prevent its displacement or deformation of the body in weak and moving soils. The base is a compacted sand and crushed stone pillow, which is poured into a specially prepared trench. The size of the trench is usually selected so that its walls have a gap from the walls of the storage tank of at least 30 cm. This is required to minimize the effect of heaving soil layers.

However, if the groundwater level is located at a level of up to 1 m, this will not be enough and it will be necessary to additionally fill in a concrete monolith or lay a finished reinforced concrete slab, after which it must be waterproofed and insulated. It will serve not only as a base, but also perform the function of securing in case of insufficient filling of containers, preventing them from floating up. Failure to use insulating layers can lead to cracking of the concrete and loss of strength. Sometimes drain pipes are installed at the bottom to drain water from the trench.

covering the finished septic tank after fixing with concrete

The supply pipes will also require the laying of a sand-crushed stone layer in order to prevent its damage in case of possible swelling. After that, it is necessary to install a septic tank and fasten it to the anchor straps to the concrete base, as well as to waterproof it. Pipes are connected, and then a sand-crushed stone composition with the addition of dry cement is poured on the sides of the container. The size of crushed stone should be up to 5 mm.

At the final stage, pipes are installed for ventilation of the sewage system and the septic tank is covered with earth. Simultaneously with the filling, the container is filled with water by about 1/3 of its volume. The height of the ventilation pipe must be higher than 60 cm above ground level.

What to do if water comes in while digging a trench?

It should be noted that it is strictly forbidden to carry out installation work in the presence of water in the trench. Therefore, it is worth choosing one of the options for solving this problem, which are given below:

Use a drain pump to pump out the accumulated water.
Carry out work in the winter. However, as a basis, use ready-made reinforced concrete slabs rather than pouring a concrete solution.
Use the method of ground installation of a septic tank with forced pumping of wastewater.
Make a sealed monolithic frame in the form of a box according to the size of the trench.

How to implement a soil water purification system?

Since the water level can change dramatically depending on the season, it is not always possible to implement filtration field systems. Therefore, special filter cassettes are used, which are located directly on the surface of the earth or on hills. For this, a layer of soil is removed to a depth of 30 cm and 25 cm larger on each side. A 30 cm high sand cushion is poured onto the bottom with tamping and leveling.

After that, concrete blocks are placed around the perimeter, which are fixed in such a way that they are airtight. Crushed stone with small fractions is poured into the resulting box, on which the cassette will be directly installed. Then pipes for water supply are brought in, connected to the cassette and the box is closed with a concrete slab with a hole for ventilation. Usually a ventilation pipe should be installed in the hole so that the smell goes upward by the action of the draft, and does not accumulate in the yard. The finished structure is covered with earth and decoration is performed using various landscape design techniques.

If the soil in winter freezes to a depth greater than the height of the embankment, then the cassette in the upper part should be insulated with foam plates or expanded clay, while it must be completely waterproofed.

If the central sewerage system is inaccessible, the owners of houses and summer cottages install an autonomous system for sewage treatment. A septic tank for high groundwater is built according to special rules, otherwise the device will quickly become unusable. If the groundwater level (GWL) in the area is less than 1 meter, carefully select the model of the septic tank and take measures to protect it from the harmful effects of subsurface moisture.

Problems of arranging sewerage at high ground level

The installation and operation of a septic tank with high groundwater is complicated for several reasons:

Labor intensity of manual execution of earthworks. Digging a foundation pit or backfilling while standing in the water is difficult and uncomfortable.
Difficulty performing soil post-treatment. It is practically impossible, since wet soil is not able to absorb water. For this reason, the construction of a filtration well or filtration fields is ineffective. To get out of the situation, the filter elements are placed above the ground, on a special platform. Such a technical solution requires additional costs - a drainage pump that pumps the contents of the septic tank into the infiltration tunnels (cassettes). To prevent shallow cassettes from being blown apart by frost in winter, they are covered with earth: such a mound can be disguised as a flower bed.
Inefficiency of a prefabricated septic tank made of concrete rings. The most popular option for local sewerage, due to high humidity, almost always loses its tightness. As a result, runoff seeps into the soil, and external moisture enters the well. What if there is groundwater in the septic tank? The answer is obvious: you have to call a flusher. Otherwise, liquid from an overfilled container may flow in the opposite direction through the outer pipes.
Possibility of "floating" of the plastic reservoir under the pressure of groundwater. The phenomenon, due to the low weight of the structure, threatens to rupture the sewer pipeline. To "anchor" the container, it is mounted on a concrete base and rigidly fixed to it. If the septic tank floats up, you will have to pump out the drains, dismantle and flush it, and then reinstall it.

Preventive measures at the sewerage design stage, the choice of the optimal treatment plant model will help to neutralize the disadvantages of a high GWL.

Requirements for a septic tank and its placement

When choosing a septic tank for a summer residence or a house in an area with high groundwater, take into account the following design characteristics:

Tightness... Since the hull will be in constant contact with wet ground, even the most thorough waterproofing will eventually deteriorate. The best option is a one-piece plastic container. If you choose a cast concrete tank, you will have to provide the ability to enter and work on the site of the crane and freight transport. In addition, concrete gradually begins to pass water, even if its surface is treated with hydrophobic compounds.
Dimensions (edit)... When choosing a model by size, they take into account the peculiarities of close ground moisture. The height of the tank should not be too high: you will have to dig a deep hole under it, and it will be filled with water all the time.
Volume... It is determined by calculating the average three-day amount of wastewater entering the sewer. The number of residents and the devices connected to the sewage system are taken into account: a toilet, a washing machine and dishwasher, a shower stall, a bath (its capacity also plays a role). A small margin is added to the estimated volume of fluid drainage. It is important that the container is not empty, otherwise microorganisms processing waste may die due to lack of nutrition.
Constructive execution... So that the septic tank does not float with a high groundwater level , it is securely fixed with clamps or ties. In this regard, a design is more convenient, in which there are already hinges or lugs for fixing.

The cleaning system is located, maintaining generally accepted sanitary standards: at a distance of at least 5 meters from a house or road, at least 15 meters from a well or well. There must be at least 30 meters to the open reservoir.

Installation features

When deciding how to make a septic tank, if the groundwater is close, sometimes developers install an ordinary single-chamber storage device without burying it in the soil. Such a scheme allows you to save materials, reduce the labor intensity of installation and speed it up. But the accumulative autonomous sewage system is justified only when servicing a small summer cottage with a small number of residents and sanitary equipment. In other cases, the dimensions of the tank will turn out to be too large, but, despite this, you will often have to call a sewage truck.

The most rational for a high groundwater level will be one of three options:

Installation of a three-section anaerobic septic tank. In the first compartment, the wastewater is settled and divided into fractions, and in the second and third they are further purified. Thanks to infiltrators used in factory models instead of filter wells, 95% of the treated liquid is absorbed into the soil. Usually the product is sold disassembled: its assemblies are assembled on site according to the diagram supplied by the manufacturer.
Self-assembly of the sewerage system with an infiltrator from sealed plastic tanks or eurocubes of suitable volume. The resulting compartments are connected with pipes.
Installation of an aerobic septic tank. It is a bioremediation station, which is supplied with oxygen necessary for the activity of aerobic bacteria. To ensure the natural flow of air, a biofilter is installed - a plastic tank with expanded clay and a special ventilation system. There are volatile filter models in which air is forcedly pumped using an air compressor for aeration.

To independently install an anaerobic wastewater treatment system in the presence of high groundwater, proceed as follows:

They dig two wells at a distance of 2 meters from each other. The dimensions of the pits are calculated so that between the walls of the containers and the earthen slopes there are 15 cm on each side. In the pits, the bottom is leveled (control the result by level), sand is poured with a layer of 30 cm, and rammed. A reinforced concrete slab with special embedded loops is laid on a sand cushion. If the passage of lifting equipment for laying a massive reinforced concrete slab is difficult, the bottom of the wells is poured with concrete on their own, after having installed the embedded parts for fixing the tanks.
Using a bandage, each container is attached to a concrete base (belts are passed through its top cover). The manufactured sections are connected with a pipe for overflowing water. The drain from the house is brought to the first tank. Without filling the wells with earth, they proceed to the next stage.
They dig a hole no more than 0.5 meters deep, around the perimeter half a meter more than the cassette. The recess is filled to the top with sand and rammed, concrete slabs 250 mm high are placed along its contour. The resulting container is filled with crushed stone of the middle fraction (20-40 mm).
Cassettes are placed on a crushed stone pillow. They are connected to the second tank, in which a drainage submersible pump is installed (before that, the electrical wiring is mounted to connect the equipment). Be sure to install a float switch with a moisture-resistant cable to start the pump when the tank is filled and turn it off when the minimum level is reached. It is better to play it safe and put two pumps: the float of the backup unit is set to a higher activation level so that it will work in the event of a malfunction of the main one.
In the manufacture of sewers, the factory infiltration cassette can be replaced with a homemade device. For this purpose, they take an oblong plastic container without a bottom (similar to a pipe), make many small holes in it for the settled liquid to exit into the ground. The cassette is used only in combination with a septic tank, otherwise the holes will be clogged with untreated drains. At the exit from the infiltration tunnel, a ventilation pipe is installed.
Backfilling. To protect the plastic from off-season soil heaving, the wells are filled with a special composition: 5 parts of sand to 1 part of dry cement. The filling is carried out gradually, compacting and spilling each layer with water. To prevent the flexible plastic from bending, the chambers are gradually filled with water - so that the liquid level constantly exceeds the level of the soil backfill.

It is more convenient to carry out installation work in the summer, when the GWL is at its lowest. If the container is still filled with water, it is pumped out, and then the installation is continued. It is recommended to arrange a ring drain around the wastewater treatment plant. Dig a trench, buried 20 cm in relation to the border of soil freezing. They make a sand cushion, lay perforated drainage pipes for the drainage of groundwater in a geotextile shell, sprinkle them with sand and gravel.

Manufactured models

If preference is given to purchased installations, the question arises: which septic tank is the best with high groundwater? There is no definite answer here, since equipment is produced with different technical data, in a wide price range.

Tank (manufactured by Triton Plastic). Universal three-chamber septic tank made of plastic. In the second section, anaerobic purification takes place, the third can act as a biofilter.
"Mole" (Aquamaster company). It is equipped with an anti-float hull and a compact biofilter.
"Multplast". Multi-chamber model, complete with a drain pump. If desired, you can install an aerator and upgrade the installation to the level of a deep cleaning station.
Bioton-B (PolymerProPlus company). Consists of three sections, also includes a biofilter and a compartment in which a drainage pump can be placed.

Owners of suburban areas with a high groundwater table usually have difficulties with the arrangement of autonomous sewerage and drains. In wetlands, cesspools quickly fill up with drains, and the cost of sewerage services becomes quite high. But it is possible to arrange an effective septic tank with a high level of groundwater, if the owner of the site is ready to increase the volume of construction and incur additional costs for the purchase of a finished installation. The investment of additional funds will subsequently pay off for the flawless operation of the sewage system and the absence of problems with its maintenance.

A septic tank, in fact, is a combination of a cesspool and a treatment plant, where wastewater from the life of residents of private housing construction gets. The use of toilets, baths, washing machines and dishwashers creates a large amount of waste water that must be disposed of in an environmentally friendly manner.

Modern septic tanks provide accumulation, biological treatment, wastewater disposal in two stages:

Contaminated wastewater enters the first chamber of the tank, where it settles and is purified for the first time. Solid heavy particles quickly sink to the bottom, and the water purified from them enters the next chamber.
In the second chamber, the decomposition of organic compounds, of which the sewage consists, takes place with the help of anaerobic microorganisms. The water becomes even cleaner and enters the third tank or a system of special filters for final purification.

Understanding the principle of operation of a septic tank will greatly facilitate the owner of a suburban area, his choice and installation.

What problems does a high level of groundwater create?

The height of waters lying at a distance of 0.5-1 m from the earth's surface is considered high. With such a depth of occurrence, problems with the sewage system inevitably arise, and difficulties arise with its maintenance.

Flooding. Devices built of bricks or concrete rings are often flooded due to groundwater movement and ground heaving. The lack of tightness in such installations facilitates the penetration of liquid inside, as a result of which the volume of effluents in the device rapidly increases. In the best case, the owner of the house building has to call a car for sewage more often, in the worst case, the sewage, mixed with feces, can get into the sewer and flow through it to the toilet and bathroom. If the device overflows, its contents can spill onto the area and spoil the soil.
Ascent. The accumulation of groundwater from heavy rainfall or melting snow can push the lightweight plastic rig upward if it has not been secured with a concrete pad. In the process of pushing out, the septic tank can tilt, the fecal masses splash out and fall into the soil. And when the structure moves, a sewer breakthrough may occur, the owner of the site will incur unplanned costs for its restoration.
Drainage. According to SNiP, there must be at least 1 m of earthen layer between the groundwater and the filtration field that filters the water at the last stage of purification. With a high occurrence of groundwater, this condition is simply impracticable, as a result, the surrounding water bodies are polluted due to insufficiently purified water entering the soil.
Destruction. Groundwater with high acidity or alkalinity gradually destroys the material from which the septic tank is made, especially concrete or brick. In addition, the housing or sewer pipes can be damaged by sharp stones brought in by the moving groundwater.
Complex installation. When installing the structure, due to the accumulation of water, the process of digging a pit and pouring a concrete pad is complicated. Installing off-the-shelf cleaners becomes more time consuming.

How to determine the depth of the groundwater level

Before installing the septic tank, it is necessary to accurately measure the height of the groundwater in order to avoid errors during installation and during further operation. There are several ways to do this.

There are 4 ways to independently measure the groundwater level. Each of them allows you to accurately determine the depth of the aquifer.

Drilling rig. For this method, you will need a garden drill and a rod with a length of at least 2 m. On the rod, markings are made along the length with an interval of 10 cm. Next, you need to drill a well to the entire depth of the drill and wait a day for moisture to accumulate. Sometimes water comes out immediately after drilling, but these are rather isolated cases. The next day, using a rod, the height of the water is measured. For accurate measurements, you can make a number of wells throughout the site and measure the level for several days in a row. For the design of the tank, the smallest value of the results obtained is taken.
By vegetation. You can determine the GWL at the site by the wild plants growing on it. Below is a table of indicator plants, by the presence of which one can judge the proximity of the aquifer. In addition to these plants, the high humidity can be judged by the rich growth of sorrel and the rapid development of currant bushes.
On the nearest bodies of water. If there are dug wells nearby, the necessary information can be obtained by looking into them and determining at what distance from the surface there is a water mirror in them. It is best to do this after heavy rainfall in order to get an accurate idea of the possible rise of groundwater. The presence of wetlands in the district indicates that the groundwater is located close to the surface.
By signs. There are some folk signs, based on which one can draw a conclusion about the desired parameter at the summer cottage. Morning dew and evening fog are sure signs of a shallow aquifer. More about high humidity can be said about the abundance of midges, mosquitoes and the absence of rodents in the local area.

Seat selection

It is necessary to start the device of a septic tank with high groundwater by determining a suitable place, while it is important to take into account all SNiPs.

The optimal location of the sump must meet important conditions:

The distance to housing construction and other buildings on the territory of our own and neighboring plots, as well as to the road zone, must be at least 5 m;
The distance from the sewerage system to the nearest water bodies is at least 30 m;
It is supposed to measure at least 50 m to the well with drinking water.

Model selection

After determining the optimal place for installation, you should decide on the type of septic tank. First of all, the required volume of the device is calculated. To calculate, the volume of wastewater accumulating per day is multiplied by 3.

The device, which will be installed on a site with a high ground water level, must meet a number of requirements:

Complete tightness;
Good strength;
Reliable fastenings;
Competent drainage.

For arranging a septic tank in the vicinity of the aquifer, experts recommend purchasing models assembled at the factory. These products are completely sealed, made of durable, durable materials and are ready for installation.

Sometimes the owners of the sites prefer to build septic tanks from their usual building materials with their own hands or with the involvement of professional builders. The devices are additionally equipped with reinforced waterproofing. Concrete, brick, or old iron / plastic barrels are commonly used to build the device.

Concrete septic tank

When choosing concrete as a building material, it is undesirable to use reinforced concrete rings, since the installation of them quickly collapses and loses its tightness. A three-chamber concrete septic tank with a high level of groundwater is best done in the form of a monolith. Monolithic concrete devices are easier to give the required tightness, they are able to withstand high pressure, do not float, their service life will be much longer than that of a building made of reinforced concrete rings. An additional advantage of concrete septic tanks is their low cost in comparison with more expensive materials.

Installation of a concrete monolith consists of the following steps:

Digging a pit;
Formwork construction;
Reinforcing mesh formation;
Pouring the bottom with concrete;
Pouring of external walls and partitions;
Roof formwork construction;
Pouring the roof;
Arrangement of a soil embankment;
Installation of ventilation and hatches.

Brick septic tank

When installing a brick sump, the proximity of the aquifer will create difficulties when laying its bottom and walls. Ready-made brick installations need reinforced waterproofing to prevent fecal matter from entering the soil.

The process of building a brick septic tank is similar to installing a concrete one. Instead of the stages of formwork construction and concrete pouring, the bottom, walls and roof of the device are laid.

Plastic septic tank

The materials for the construction of plastic devices are usually plastic containers and eurocubes. Plastic septic tanks are not as practical as buildings made of heavier materials, but they are quite suitable for constructing a sewage system in the country with your own hands. The disadvantages of such materials are the risk of floating due to their low weight, the possibility of cracks appearing when soil heaving.

Before installing plastic septic tanks, it is necessary to put a concrete slab at the bottom of the pit for anchoring an easy installation. The plastic, firmly fixed to the concrete slab, will not be able to float when the groundwater level rises.

Factory septic tanks

The best option for arranging an autonomous sewage system in a house area with a high level of groundwater is septic tanks manufactured at the factory. The modern market for plumbing fixtures and fittings offers products of different sizes and the most diverse modifications. The owners of suburban areas have the opportunity to choose the product that is most suitable for their sewage project.

The disadvantages of factory septic tanks are their high price and attachment to power grids. Fresh air must be constantly supplied to the tanks for cleaning, which is supplied by means of electrical equipment.

If the owner of the site has the skills to carry out construction work, he may well install a factory septic tank on his own, with the help of ancillary workers. Installation is carried out in several stages:

Digging a foundation pit. When digging a pit by hand, the main problem is the water coming in during the digging process. It is necessary to scoop up the incoming moisture at the same time as digging, sometimes you even have to connect special equipment for pumping. When using an excavator or other equipment for digging, a lot of liquid does not have time to run in, and nothing interferes with the installation process of the device.
Sand cushion construction. Sand up to 10 cm thick is poured onto the bottom of the dug pit.
Installation of a concrete base. A concrete slab with fasteners for fixing the septic tank is lowered onto the sand cushion. Sometimes, instead of the finished slab, formwork with reinforcement is installed and concrete is poured. In the case of pouring, it is necessary to wait a week until the concrete has completely hardened.
Preparation. A heating cable is mounted on the septic tank and waterproofing is sprayed.
Installation. The prepared installation is lowered into the pit and installed on a concrete base.
Fixation. With the help of special fasteners, the septic tank is attached to the concrete slab.
Lining up communications. Sewer pipes are connected to the device, the joints are sealed.
Sand filling. After connecting the communications, the operation of the heating cable is checked and the septic tank is covered with sand, immediately equipping an earth embankment on top of the purifier.

After installing the septic tank, a filtration field or filtration cassette is built next to it for the final purification of the filtrate.

TOP 10 factory cleaners

Tank. Excellent value for money. Independent of power consumption. Robust case. A wide range of models with different volumes and devices.
Triton. Excellent service life up to 50 years. Septic tanks of this brand require anchoring during installation. A wide range of models of different sizes and shapes.
Leopard. Three-chamber purifiers with 2-level biofiltration. Consumers note strength, reliability and durability.
Tver. High capacity models. Requires a constant source of electricity and regular maintenance.
Leader. 6-chamber septic tanks with airlift and aerators. Do not require biological additives for wastewater treatment.
Ecopan. Withstand heavy loads. Recommended for installation in heaving soils.
Unilos. Complex wastewater treatment process, consisting of mechanical and biological stages. Reliable, easy-to-maintain models.
Yubas. Robust septic tanks suitable for efficient operation with long breaks for up to 3 months.
Poplar. Resistant to temperature extremes and loads. Equipped with airlifts, compressors and aerators. manual and mechanical removal of sludge is provided.
Topas. Reliable autonomous sewerage system made of high quality materials. It is in demand among Russian consumers.

Features of operation

An autonomous sewage system will last a maximum period if you adhere to the recommendations of specialists and the basic rules of use:

Do not throw large rubbish down the drain;
It is good to insulate and waterproof the system;
Regularly pump out accumulated waste fluid from the septic tank;
Avoid the ingress of fats using special grease traps;
Do not use chemicals when using biological treatment of effluents in the septic tank chamber.

If you approach the installation of a septic tank responsibly, take the time to draw up a project, select materials, adhere to operating rules - the autonomous sewage system will function without interruptions for many years.

Also on the topic

How to remove blood in CS GO: clearing a card from debris How to clean a CS from debris

Church of St. Nicholas in Tolmachi

How much does cs 1.6 cost per incentive? Instructions after purchase

Red ringing. Attached temples. Where to call on Bright Week

6 russian assembly download steam