Septic tanks in winter at the dacha, its operation - do septic tanks freeze in winter

The presence of an autonomous sewer system in a country house is one of the mandatory requirements that potential owners place on them. And this is correct - few people want to jump outside for natural needs when the temperature drops below -20...-30 degrees, and stays at this level for weeks. Therefore, many modern country houses have all the benefits of civilization. But many people have a completely reasonable question: “Will sewerage cause problems in winter?” It will be very useful to study this issue in as much detail as possible.

Operating a septic tank in winter

If the system works permanently, then there is nothing to be afraid of. Septic tanks operating in winter do not require additional heating or any special conditions. The fact is that constant drainage of wastewater at room temperature will prevent the system from freezing. The most important thing is not to open the lid in extreme cold, otherwise the liquid may freeze. The lid itself is already insulated and fits hermetically to the tank. There is no need to insulate it, since biomass, when decomposing, releases additional heat. In addition, the compressor operates permanently.

How will the septic tank work in winter if you come to the dacha only on weekends? Isn't it better to turn it off? No, because bacteria will only multiply with constant aeration (bubbling). To save money, you can install a special relay that periodically turns off the power. However, even systems for families of four to five people are not particularly expensive in terms of electricity.

Using septic tanks in winter

In order not to create intrigue, you should immediately say that the septic tank in winter can be used in the same mode as you are used to. If it is installed in a house or cottage where people live permanently, it will clean drains just as effectively as in the summer.

To do this, you just need to take care in advance about additional insulation of the station, inlet and outlet pipes, since most often it is the freezing of pipes that causes problems in the operation of septic tanks.

The best argument in favor of operating local treatment facilities in winter may be that construction companies install stations for their clients all year round, including in winter, and immediately put them into operation.

However, in order to better understand how to properly prepare and operate a septic tank in winter, we recommend that you read the material below.

Preservation of the septic tank

What to do with a septic tank in winter if you are not going to live in a country house during the cold season? It must be preserved without fail. The main disadvantage of preservation is that the spontaneous generation of bacteria in the spring will take from one to two weeks. Preservation instructions are included with each installation. The whole job will take you about an hour or two. If you don’t want to do it yourself, you can call specialists.

We list all the stages of conservation of volatile systems:

disconnection from power supply. All biological treatment stations are energy dependent. They are turned off using a remote control or switches in the house. In some stations, you must first turn it off using a key located on the control unit of the installation.
cleaning the system chambers from sludge.
Removing the compressor.
removing the pump. After this, the product is inspected, cleaned and repaired if necessary.
checking the fluid level. If there is less water, add clean water so that each chamber contains 2/3 of the total volume.
install floats. If you live in a place with harsh winters. They are placed so that the pressure on the walls of the tank is reduced, and the resulting ice does not break the body of the installation. To do this, use ordinary plastic bottles of 1.5, 2 or 5 liters. Fill them (about a third or half) with sand and lower them into the tank so that the top of the bottles is held vertically on the surface. The caps are not screwed on completely. A rope is tied to the necks of the bottles to make them easier to get when re-opening begins.
insulate the station cover. This is done using penoplex foam 5 cm thick. Usually four sheets are needed. The walls and cover of the station's insulating box are assembled from foam sheets. To prevent the penoplex from getting wet and preserve its properties, the finished box is covered with plastic film and pressed down around the perimeter with stones.

What measures are taken to prevent sewer pipes from freezing?

Lay pipes in the ground to a depth of 70 cm to 2 meters, depending on climatic conditions.
The rule should not be ignored: sewer pipes are laid at a certain angle. SNiP dictates the following standards: pipe diameters 50 mm slope = 0.03, 110 mm = 0.02, 160 mm = 0.008, 200 mm = 0.007
Provide thermal insulation. Sewer freezing can be prevented by: natural insulation, heating or using heat-insulating materials.

Natural insulation involves placing pipes at a depth below the freezing point.

Heating can be a cable built into the pipe itself, or wrapped around the pipe.

Pipe insulation: roll method - insulation is wound around the pipe (mineral wool and synthetic rubber); molded method - rigid insulation made to fit the diameter of the pipe (cylinders, half-cylinders with and without aluminum lining). They are based on polyurethane foam materials (foamed polyethylene); laying in a box involves covering the pipes with building material (wood, plastic, gypsum board) and filling the box with loose foam or polyurethane foam.

If communications are laid in wet soils, it is necessary to provide insulation with a water barrier.

Does the septic tank freeze in winter?

Yes, if it was not properly preserved for the winter. Also, the septic tank can freeze in winter if errors were made during installation. This mainly concerns not so much the septic tank itself, but the pipeline. Let's analyze the main errors during installation and operation:

the pipeline is not laid deep enough, above the freezing point of the soil. At the same time, the highway is poorly insulated.
During installation, a pipe of smaller diameter or low slope was used. The error led to stagnation of flows, and the water in a certain area froze.
Fat deposits inside the pipeline do not allow drains to pass freely.
there are no inflows of warm liquid into the pipeline. For example, due to a malfunction, only cold water flows into the main line.
the system is located far from a residential building.

If it is not possible to bury the septic tank

Alas, in some cases, dacha owners simply do not have the opportunity to install a septic tank below the freezing depth of the soil. In this case, insulation should be approached much more seriously - this is no longer a precaution, but a necessity.

The septic tank should be insulated when installing it. Expanded clay or foam chips should be used as thermal insulation materials - low cost combined with good thermal insulation make these materials the optimal solution to the problem.

Some attention should be paid to the thermal insulation of pipes leading to the septic tank. It is best to use polymer pipes - they do not rust, are light in weight and are relatively inexpensive, for which they are highly valued by specialists. The pipes must be wrapped with a suitable thermal insulation material, and then placed in a shell of asbestos-cement pipe, which protects against any mechanical damage.

Insulation of sewer pipes

When laying pipes, special attention should be paid to the slope. The minimum slope should be 2 degrees, that is, 2 cm of slope per 1 meter of pipe. However, in practice, experts prefer a slope of 5-7 degrees, which ensures rapid passage of water along with the contents through the pipes. But you shouldn’t get too carried away - it’s better that the slope falls in the range from 2 to 7 degrees.

If the pipes are laid at a lower slope, there is a danger that water will not move through them. If the slope is too large, water flows through very quickly, but solid waste can linger in the pipe, accumulating and clogging it. Of course, when laying, you should avoid using corners and turns - they significantly increase the risk of blockages. When installing a sewerage system for a one-story house, pipes with a diameter of 50 mm are suitable. If we are talking about a two-story house, on the upper floors of which there are sinks, a toilet and a bath, then pipes with a diameter of 200 mm are better suited.

What to do if the system is frozen?

There are several ways to defrost a drain.

pouring boiling water. Using a rubber hose inserted into the pipe and a funnel, boiling water is poured. The hose should rest against the ice plug. When the plug melts, the hose is pushed through the pipeline to completely dissolve the ice.
flushing with saline solution. Having heated the water to 70 degrees using the boiler, open the tap and drain the water into the bathroom. Pre-dissolve salt in it (1:10). We wait half an hour. If the ice plug has not thawed during this time, you should use the following method.
heating the pipe. Using a construction or household hair dryer, heat the section of the pipe that goes outside.
caustic soda. This method should help if the traffic jam does not form near the house, but closer to the system. Mix caustic soda (3 kg), hot water (6 l), boiling water (1 l). Pour the mixture down the drain. The large amount of heat from the chemical reaction should melt the cork. This will be noticeable if the mixture begins to flow freely into the drain. You should work in a respirator, gloves and goggles.
heating the pipe with excavation of the route. If none of the previous methods gave results, then you should use this method. To determine where the plug formed, we dig a trench. Next, using a mallet, tapping the pipe, we find out the location of the ice. The area with the congestion is heated with a hair dryer.

If the septic tank is already frozen, then you can use the following methods to defrost it:

— Watering the sewer and septic tank with hot water. Hot water will defrost the ice if it has not yet become very thick.
— You can make a special reagent at home from salt and baking soda. It is necessary to make such a solution highly concentrated so that the sewer system can be cleaned from the inside. This is the most effective and cheapest method of defrosting a septic tank.
— Application of heating cables. This requires special devices and heating cables. These cables are wrapped around the perimeter of the septic tank and heated until the ice completely melts. However, this is a rather expensive method, the use of which also requires certain professional skills.

To avoid problems with the operation of the septic tank, it is necessary to use insulating agents at the design stage and then during installation, as well as maintain the correct installation depth. If it is not possible to carry out the installation work yourself, then it is best to contact a specialized company.

Installing the system in winter

We already know that the system can be successfully operated throughout the cold period. The next advantage is that the septic tank can even be installed in winter. Let's look at the installation algorithm step by step:

First of all, the area for the foundation pit is cleared of snow.
Mark the dimensions of the pit on the ground and begin digging.
drill a hole in the tank for the sewer pipe. Next, insert the pipe into the hole and seal it.
drill a hole to drain purified water.
At the bottom of the dug pit, a sand base is made.
The tank is carefully lowered into the pit so that the lid is above ground level. Next, level the system, cover the edges with sand, and pour water inside.
An alarm is mounted on the tank lid.
A pipe is inserted into the hole intended for the water drainage pipe and sealed.
digging a trench to the house.
assemble and install a pump that will discharge purified water.
a sewer pipe is inserted into the system. The trench is filled with sand.
An electrical cable is connected to the system.
compressors are connected.
install a pipe that will drain purified water.

Advantages of structural design at subzero temperatures

The advantages of installation in winter are as follows:

low level of groundwater, which guarantees the absence of water in the developed pit. This is especially important in areas with elevated levels of underground sources and in the presence of open water bodies near them;
gardening and gardening activities are not carried out, which causes the absence of people at the dacha and will not cause additional inconvenience to the owners during the installation period;
During the winter period, there is a significant decline in orders for the installation of autonomous sewage systems, which allows you to get discounts and allow specialists to carry out installation without haste and with maximum productivity. This completely compensates for the difficulties of soil development, although in warm weather it is much easier;
for professionals, the work will not cause any particular difficulties, the only exception is negative temperatures below 15 degrees, at which it is difficult to solder polypropylene.

Installation of a septic tank made of concrete rings at sub-zero temperatures

When working with concrete rings in cold weather, the issue of concrete and formwork disappears. But there remains an equally important issue with sealing the seams. After all, special sealants are used to seal seams. And they are not at all designed to work at sub-zero temperatures, and even more so in severe frosts. Therefore, there will not be the necessary adhesion with concrete rings. Also, the sealant will not be able to achieve the required performance characteristics due to simple freezing. And in this state, the sequence of processes for normal solidification will not occur.

The result will be disastrous, because there will be no complete sealing. Groundwater will get inside and you will have to call a vacuum cleaner very often. Or, on the contrary, dirty water from the septic tank will end up in the ground. And if you have a well or a nearby well, then the contaminated wastewater will reach your drinking water.

Conclusion! If you decide to install a septic tank in winter, then feel free to order an autonomous sewerage station. If for some reason this does not suit you, then the safest thing to do is wait for the warm season.

Frequency of maintenance of sewage tanks

The main action required by autonomous drainage systems is to empty the tanks of accumulated waste. In the summer, fecal pumps are used for this; containers are less often cleaned manually. Since the sewage system is operated in the same way in winter as in summer, the cleaning process is carried out in the same way. The frequency varies, some have to perform the procedure every month, others call the vacuum cleaners once every six months or even a year. In addition, the normal activity of waste-decomposing bacteria ceases during the winter, necessitating more frequent cleaning.

The tanks are pumped out as they are filled. As a rule, the limiting state is considered to be 2/3 of the container filled. In order not to miss the right moment, many owners install float sensors that signal when a critical level of filling a septic tank or cesspool has been reached. This control method is used by owners of private houses. For summer cottages, installing special devices does not make sense. As a rule, the sewage system in a country house is not used in winter, so it is simply pumped out at the end of the summer season.

In a private house, control over the level of wastewater should be carried out regardless of the time of year. The system is used in winter and summer in the same way, so the rate of filling the tank is the same. Owners of private houses planning to build an autonomous system are interested in whether it is possible to pump out sewerage in the winter. The answer here is clear - it is possible and necessary. It is impossible to overfill the container, so the procedure is performed regardless of the time of year with the same frequency as always. The fears of home owners are understandable - if the waste freezes, there will be no way to remove it from the container. However, the treatment technology has long been developed and allows you to pump out wastewater at any time of the year.

Features of pumping out pulp in winter

As a rule, operating reservoirs rarely freeze in winter. The effluent is warm, and fermentation and decay processes occur in the pulp mass, during which heat is released. However, if the region experiences severe frosts, the waste may freeze. Some septic tank models have an electric heating function that allows you to keep the pulp in a liquid state. If this is not possible, the container is heated using a steam generator. After this, you can pump out in the usual way. The process does not take much time, so the pulp usually does not have time to freeze.

In any case, the home owner needs to anticipate the possibility of waste freezing and schedule cleanup for warmer days. If the container does not require frequent pumping, the procedure is performed in the fall and spring. If the tank volume is small, you have to calculate the schedule to avoid the coldest days.

The ability of waste to maintain above-zero temperatures depends on adherence to technology during system assembly. If the installation of sewerage in a private house in winter was carried out according to the rules, the pulp will freeze only when extreme cold occurs. The septic tank and supply pipeline must be properly insulated. In general, installation of sewerage systems in winter is a rather controversial issue on which there is no consensus among experts. Let's take a closer look at it.

Also read: SanPiN sewerage: sanitary requirements, standards

In practice, it was found that most often pipes with a diameter of less than 110 mm freeze

The septic tank freezes most often because:

The drainage system is broken (the reason is in the sewer pipes); water stops coming out of the septic tank, it overflows and the drains inside freeze
If the septic tank is located at a considerable distance from the house, in winter the water may freeze at the junction of the pipe and the septic tank
The septic tank was not preserved for the winter. You can read about how to properly preserve a septic tank before the onset of frost in our article
The septic tank has not been used for a long time or the amount of wastewater entering it has sharply decreased

Before the onset of winter, experts recommend pumping out the septic tank, and then there will definitely be no problems with pipes freezing (just don’t pump out the drains completely, it’s better to leave about one third of the drains)

Details

How to insulate a system

For thermal insulation of a septic tank at a summer cottage, sawdust, leaves, and straw are used. To strengthen the material, cobblestones are placed on top. If the treatment plant is built from bricks, concrete rings, or plastic tanks, then other methods for insulation are required. The devices last for many years, so the materials must withstand a long service life so that they do not have to be replaced frequently. For example, straw may rot.

There are main methods that are used as insulation:

1. The septic tank is filled with expanded clay, which is based on clay. The material consists of porous granules of different sizes. Expanded clay has good qualities for use, it does not rot, does not allow fungus to form, and at the same time has an affordable price. Expanded clay is also resistant to moisture, has a long service life, and insulates the structure well. The material should be poured into the space between the septic tank and the soil in a layer of more than twenty centimeters. It is important to strengthen the insulation in the place where the sewer pipe enters the container.

2.Use mineral wool. It is easier to install cotton wool than to use expanded clay. The material insulates the septic tank at a high level, is resistant to chemicals and temperature changes. If the material is subject to external influence, then it retains its qualities, but mineral wool quickly absorbs water. A waterproofing film must be placed on top of the material. Mineral wool comes in the form of sheets that are attached to the septic tank with glue or dowels.

3.Use of extruded polystyrene foam. The material is resistant to temperature changes, is not afraid of moisture, and is easy to attach to a septic tank because it is light in weight. Expanded polystyrene is attached to the outer wall of the device with dowels or coy. Polyurethane foam is used to treat joints between strips of material.

4.Use of polyurethane foam. The material is considered one of the most commonly used insulation materials. This insulation has different forms because it is used in different areas of construction. It is produced in the form of blocks, rolls, sheets. The material is durable and strong. Does not form mold due to humidity, withstands external influences without forming cracks. At the same time, the material is very cheap, but heats well.

5. Install the heating cable. If a septic tank is used in regions with a harsh climate, then this measure is justified. With the help of a heating cable, the septic tank will withstand any temperature changes. It is installed in septic tanks powered by aerobic bacteria. The entire system should be insulated using sheet or bulk material, and the cable itself should be protected from moisture.

In addition to the cleaning device, the pipeline should be insulated. The pipes are wrapped in mineral wool material, and waterproofing is placed on top of the mineral wool. The waste pipe is fixed using a foam insulating box. If the soil settles, the pipe will not change its angle of inclination.

When insulating with your own hands, you must adhere to some rules:

1. The thickness of the insulating layer depends on the climatic characteristics of the region, the composition of the insulation, and the depth of the septic tank in the ground.

2. if the septic tank is located in the northern region, then insulate the septic tank from the sides, from above.

3. when insulating a pipe entering a septic tank, you should remember that the pipe can freeze, even if it is correctly laid at an angle. The diameter of the pipe may be reduced to a minimum size.

4. if the septic tank is used at the dacha only in the summer, it should be preserved for the winter.

How to preserve the device

If you use a septic tank only in the warm season, you should preserve the device for the winter. The procedure will reduce the negative impact of frozen earth on the walls of the septic tank.

Attention! Before conservation, there is no need to drain all the drainage from the septic tank, so that in the spring groundwater does not push the structure out of the hole, or the septic tank does not crack when the soil layers are displaced.

The conservation procedure can be carried out by specialists. Then you won't have to worry about doing something wrong. You can also do the preservation yourself, following the instructions in the instructions for the septic tank.

The following sequential steps must be followed:
1. The septic tank is disconnected from electricity, the air supply pumps are disconnected. These actions are not difficult to carry out, because there are special fasteners in the tank for this.
2. Three-quarters of all drains are drained of liquid from the septic tank, or water is added if there is a shortage.
3. insulation of pipes and septic tank lids is carried out.

Attention! Thirty days before storing the device, a product based on aerobic bacteria must be added to the septic tank. They will break down solid particles settled at the bottom of the chamber and eliminate odors. With proper conservation, the septic tank will maintain a warm temperature all winter, and the autonomous sewage system will not be affected.