The high level of groundwater prevents not only the construction of houses, but also the laying of communications - water supply, sewage pipes in such soil to lay more difficult. There is no exception here and septic tanks - for giving with a high level of groundwater, during their construction, it is necessary to take into account the condition of the soil, which may indicate the risks of flooding of installed equipment. In our article we will try to figure out how a septic tank should be arranged with a high level of groundwater.
A septic tank version for giving with a high level of groundwater
From the location of water depends on the depth of the septic tank. Ideally, the cleaning system is arranged above the location of groundwater. Unfortunately, this is not always possible, and it is necessary to lay a septic tank with a high GWL in the soil with groundwater, located near the surface.
The high-quality operation of the system in such conditions is ensured by sealing the tanks into which the drains fall. Otherwise, the septic tank will not only turn into a simple drain hole - sewage can seep into the ground, and further fall into the underground aquifers. To avoid such a scenario, it is necessary to accurately calculate the depth of installation of the septic tank and the sewage pipes going to it, and this can be done only if we know how deep the groundwater is.
A high level is considered to be finding water at a distance of up to 0.5 m from the surface. The owners of sites with groundwater at a depth of 1.5 m and more were lucky - this is also not a completely acceptable result, but it will still be easier to equip the sewage system.
The location of groundwater in the area in the scheme
You can get an idea of the depth of groundwater in several ways - preliminary and exact. The first include:
questioning neighbors about the state of the soil in their plots;
studying the flora in the plot - if moisture-loving plants prevail, then water located at a short distance from the surface;
determining the water level in the well;
digging a hole - if water appears in it after some time, it means groundwater is close to the surface.
The only accurate methods are geological samples at the site, for which wells are drilled at the site of the planned installation of a septic tank and at several other points.
Measurement of groundwater in the area in the diagram
Important! Measurements are recommended during the period of snowmelt or after long rains.
For a septic tank with a high groundwater level, the following parameters are important:
tightness - so that ground water did not get into drains and vice versa;
strength - to withstand possible displacements of moist soil;
reliable fixation - if the septic tank capacity is light, and around if water collects, then the tank can simply float;
good drainage - the increased soil moisture usually harms any materials.
The industry offers a variety of designs to ensure tightness and strength. You can either purchase a fully prepared septic tank for high groundwater levels or order an assembly of an individual design, for which plastic barrels pre-reinforced with fiberglass are used. They are hermetically sealed, resistant to external moisture. In both cases, the most important thing is to prevent them from floating up if the pit begins to fill with groundwater or rainwater. For this purpose, a concrete pad with barrels is mounted in the pit for the septic tank.
If the plans are to install a concrete septic tank, the concrete is poured onto the reinforcing mesh, it strengthens the walls and provides the necessary structural strength.
Types of septic tanks for the site with high groundwater
Drainage is one of the main problems of septic tanks for high groundwater. Disposal of the processed liquid is done in the gutter or on the filtration field. To improve the cleaning efficiency, the field is equipped on a hill. To elevate the place, use landscape decoration. Waste water is pumped to the filtration surface with a pump.
On our site you can find contacts of construction companies that offer the service of assembling and designing sewage and water supply. Directly to communicate with representatives, you can visit the exhibition of houses "Low-rise Country".
In determining the location for the cleaning system, the current sanitary norms are taken into account.
A septic tank for high groundwater levels cannot be located closer than 50 m to the well and 30 m to the reservoir.
The distance to the apartment building and plantings is at least 3 m.
The road must be at a distance of 5 m from the septic tank.
How to choose a septic tank correctly, see the video:
The system model for the treatment of domestic wastewater depends primarily on the volume of water consumed. To equip a septic tank for high groundwater, select fully assembled models at the plant or build systems on site with waterproofing works.
In addition, you can consider the easiest way to solve the problem of sewage treatment with a high location of groundwater - surface installation septic tank. Tanks are placed in a dedicated place, protected by external walls, covered with a roof. But with obvious advantages, this option has at least tangible drawbacks - the surface septic tank takes up a lot of space, plus it will be necessary to equip the pump system, since the drains will not get into it by gravity.
The market offers many options for fully prepared septic tanks designed for different volumes of recyclable effluent. Such septic tanks are made of durable plastic, and the space inside is already divided into separate chambers in which a step-by-step sewage treatment takes place. The septic tank needs only to be brought, installed in a suitable place and it is ready to work.
The best option for sewage in a private house is a septic tank without pumping, with a full cleaning cycle. In such a septic tank live bacteria that decompose all the drains into sludge and water, purified by about 95-98% - it can be used for technical purposes. Il is extracted every 1-3 years, but it can be used as a fertilizer. True, such constructions are not cheap, but given that they do not need an ashenizer machine, these septic tanks pay off within a couple of years. Since they have a completely sealed enclosure, such systems can be installed at any soil moisture, without fear that the drains will fall into the groundwater.
High and normal groundwater level
Note! You can not waste on such a biological septic tank , but simply install a sealed storage tank, from which the contents are periodically pumped out. But this is an extreme option, because regular spending on a car call will negate the initial benefit.
When equipping a septic tank from polymer containers in the soil with high humidity, a reinforced concrete pad is installed on which the entire system is installed.
Plastic eurocubes securely fastened to the base to prevent them from ascending. This solution is more economical, since it is possible to use old containers that were in use.
Layout of a concrete cushion for a septic tank
It might be interesting! In the article the following link read about the septic tank to give.
Such systems are gradually becoming obsolete, but still in demand, due to the relatively inexpensive cost of installation, durability and ease of operation. Its advantages are:
durable - soil displacement will not damage it;
has no seams, which means there is no threat of depressurization;
does not require an ascent gain;
is cheaper than industrial;
durable - in some cases it can work out about 20 years without pumping.
With a high level of groundwater, the chambers of a concrete septic tank are connected with pipes at a slight inclination in order to ensure the free flow of fluid from one tank to another. This option is suitable for a family with a high consumption of water.
Reinforced concrete pit for country sewers
For normal operation of the system, forced flow of effluents into the seepage fields or infiltration tank is required. The pump for this is usually placed in the last tank.
Important! For safety, it is better to install 2 pumps.
The biggest problem when installing septic tanks for summer cottages with high groundwater levels is water entering the pit from the soil. If the excavation is done manually, the process becomes time consuming and lengthy.
The installation of a plastic septic tank in a soil with a high level of groundwater requires the installation of a concrete cushion at the bottom of the foundation pit, which will reliably fix the tanks for cleaning. Septic tanks are attached to metal hinges that are present in ready-made concrete blocks, or they are installed during cement pouring.
Construction of a concrete cushion and drainage well
Important! If the finished slab fits, then its weight should be at least 50% of the weight of the septic tank.
In addition to fixing to a concrete pad, care must be taken of the joints between the pipes and the chambers.The joints between pipes and chambers must be carefully treated with sealant. To prevent the surfacing, the finished system is sprinkled with a layer of sand and dry cement, and then tamped.
If there is a question of the equipment of a concrete septic tank, it is better to order reinforced monolithic structures. Popular concrete rings have joints that can be damaged during operation. This is fraught with the ingress of liquid into the soil and pollution of the environment, as well as the inflow of external water into the tanks and filling them with groundwater.
Video on the phased installation of a septic tank on a site in high groundwater levels:
Even at the stage of checking the amount and level of groundwater, you can find that it is so high that water immediately seeps into the pit right through its walls. The most reasonable in this case would be to carry out work on the installation of a septic tank postponed to the driest months of the year, when the water level is lowered and the construction of sewage systems in a private house with a high level of groundwater can be carried out with minimal losses.
When for some reason this does not work, then you have to simultaneously dig holes and trenches, and in parallel draw water out of them. It is possible to simplify work only with the help of a pump, the hose of which must be lowered into a hole and pumped water not manually, but mechanically. Of course, the pump must be such that it can pump out highly turbid water with inclusions of sand.
In any case, first of all, you need to dig a hole at the lowest point and dig trenches for pipes from it, so that the water from them will drain into the hole that was originally dug out and pump out everything that has been collected by the pump from here.
True, all these problems can arise only if it is not possible to dig holes with an excavator and you have to use manual labor. In the first case, the water simply does not have time to leak into the pit in such quantity that it would prevent the work.
If a conventional septic tank is used instead of a biological wastewater treatment plant, an obligatory element of the entire system is soil after-treatment, which is performed as a filtration field or as an infiltrator. If the groundwater level is high, then the second option is preferable, although, with proper calculations, conventional filtration cartridges will work well.
The soil after-treatment system (filtration cartridges) in the
scheme The cartridges are installed in this way:
they dig a shallow trench, the bottom of which is leveled and tamped;
, concrete blocks are placed at the edges that seal the trench;
to the bottom fine crushed stone is poured;
pipes perforated on one side are fed through which planned disposal of treated effluents;
poured the filter layer and laid on it perforated tubes, which are bleached drains;
the remaining volume is filled with rubble, ventilation is improved;
the finishing stage is filling with soil and aesthetic design.
Such a filtration cassette lasts for 10-15 years, depending on the intensity of use of the sewage system, after which everything must be excavated and washed, or the crushed stone and the filtering layer must be changed.
It may be interesting! In the article on the following link read about a septic tank made of reinforced concrete rings.
Installing a septic tank with a high level of groundwater is time consuming but real. The main thing is to accurately calculate the level of water and to choose the best septic tank, based on specific conditions. It is better to entrust this work to professionals, since independent selection and installation of a structure can lead to problems in subsequent operation.