Review of septic tanks "Mole": design, advantages and disadvantages, comparison with competitors

If you need a cheap, reliable and energy-independent autonomous sewage system, then you should consider the “Mole” septic tank as its main working element. Such devices appeared on the market relatively recently, but have already gained a certain popularity, which continues to grow.

We will tell you about popular positions in the model range of wastewater treatment systems with the Mole logo. We will introduce you to the pros and cons, design features and cleaning scheme. We will give valuable recommendations to those wishing to install an autonomous sewer system using the specified treatment point.

Model range of the Krot brand

The device is available in three different models, making it possible to meet the wastewater disposal needs of both a small summer cottage and a private house with a couple of floors.

The manufacturer of the septic tank “Mole” offers customers:

• horizontal model Mole 1.17
• vertical model Mole 1.18
• vertical model Mole 3.6

All products are made of durable low-pressure plastic (LDPE), the thickness of which varies between 7-14 mm.

The material has increased frost resistance. To give the structure additional strength, 15-centimeter stiffening ribs are used.

The Mole 1.17 model is a single-chamber structure that is used mainly as a storage tank. The volume of the device is 1170 liters, which is quite enough to serve a small summer cottage. But for owners of large cottages, purchasing this device can also be very interesting.

Several of these containers, connected in series, can be turned into a two- or three-chamber septic tank of significant volume.

The relatively low price of the device and simple installation, as well as the possibility of equipping the device with additional options depending on the customer’s wishes, make Mole 1.17 a worthy alternative to a septic tank made of concrete rings or expensive VOC models.

If you need a large three-chamber septic tank with a horizontal arrangement of chambers, you can order the production of such a device in the factory based on the “Mole 1.17” septic tank model

Due to the absence of other chambers, this septic tank works mainly as a storage tank in which wastewater is naturally processed. Water clarified and purified as a result of settling is discharged to filtration field, where they undergo additional cleaning using a gravel-sand filter.

If you buy two or three horizontal septic tanks “Mole 1.17”, you can make one large treatment plant out of them, placing each device in a separate pit

Approximately once a year, the device must be cleaned using a drainage machine. In case this is not possible, you can pump out the contents of the septic tank yourself into some container of suitable volume in order to dispose of the waste later.

The inlet and outlet pipes of the septic tank are equipped with adapter couplings that allow the device to be connected to sewer lines.

Horizontal models of Krot septic tanks are relatively low, so for their installation you will need a pit that is not as deep as for the vertical model

In the standard version, the septic tank neck has a diameter of 50 cm and a height of 44 cm, but these parameters can be changed at the request of the customer.In addition to the main lid, the container is equipped with an additional lid made of foamed polyethylene.

The presence of this useful element eliminates the need to additionally insulate the device in winter. Connection location sewer pipe to the septic tank is made in such a way that if it becomes clogged, it is not difficult to clean it.

The vertical model of the “Mole” septic tank, like the horizontal one, is equipped with two covers to ensure reliable protection of the device from winter frosts

The Mole 1.8 model consists of two chambers, although it can also be supplied in a single-chamber version. The body of the product is made in the form of a cylinder, the working chambers are located vertically.

The height of the product is 225 cm, with the first chamber accounting for 150 cm. The diameter of the body can be 136 or 186 cm. This model weighs only 105 kg, the volume of the device is 1800 liters.

The Mole 3.6 model with a capacity of 3600 liters is available with both three and two chambers, which are also located vertically relative to each other. The product body has an ellipsoidal configuration.

The height of the container is the same as that of the 1.8 model - 150 cm for the first chamber and 225 cm in total. The width and length are 190x240 cm, the weight of the product is 170 kg. The height of the neck is 75 cm and its diameter is 90 cm, but these dimensions can be changed at the request of the customer.

This diagram clearly shows the design of the vertical model of the “Mole” septic tank with different options for the location of the inlet sewer pipe (+)

An interesting option of these two models is the ability to divert the so-called “gray” wastewater not into the first, but directly into the second chamber of the septic tank. “Grey” refers to the waste coming from your washing machine and/or dishwasher.They have a low degree of contamination and do not require long-term settling.

To move such wastewater into the second chamber of the septic tank, an additional pipe with a diameter of 50 mm is installed with a corresponding adapter for connection to the supply sewer pipe.

Like the Mole 1.17 model, these two devices have an additional polyethylene foam cover. Biofilters are installed inside the septic tank between the first and second chambers, improving the quality of cleaning. If necessary, the device can be equipped with a manual check valve, which will protect the device from flooding with groundwater.

Mole septic tanks can be modified to make them more suitable for specific conditions. For example, if the buyer cannot determine in advance the depth of connection of the sewer pipe, instead of the neck, a 160 mm pipe with an adapter coupling can be supplied.

Then a standard sewer pipe is attached to this adapter, with which the connection is made.

All models of the device are made with protection against floating in areas with normal groundwater levels. Where the waters are shallow, it is recommended to use additional fastening to protect the structure from floating. This element is fixed directly to the body of the septic tank and does not require connection to a concrete slab.

This diagram makes it possible to study the structure and operating principle of the horizontal septic tank “Mole”, as well as the features of installing additional elements for this model (+)

If there is a danger of the septic tank overflowing, you can use a drainage or fecal pump. In this case, you need to order an additional option - a special shelf or container for the pump. In addition, an outlet with a diameter of 50 mm is installed on the neck of the septic tank.

Design and principle of operation

If we talk about the principle of operation of the “Mole” septic tank in a simplified manner, then it can be considered an advanced sump tank. Wastewater enters the device through a sewer pipe, accumulates and is slowly processed under the influence of anaerobic microorganisms.

Diagram of the horizontal model of the “Mole” septic tank. The location of the neck of the device can be changed depending on the situation or the wishes of the customer (+)

As it is processed, the contents of the septic tank decompose into partially purified water, neutral sludge and non-biodegradable waste.

Water is discharged as needed through the drain pipe into absorption well or onto the filtration field, and the other contents are removed using a suction pump. If the volume of the septic tank is calculated correctly, then calling the vacuum cleaners and cleaning procedures can be carried out only once a year.

If we are talking about a two- or three-chamber septic tank, then the sections in such a device are separated by sealed walls, so the contents of different departments do not mix.

The movement of wastewater from one chamber to another is carried out through special overflow holes. As already mentioned, part of the sewage waste - gray waste - can be immediately brought to the second chamber of the septic tank.

The septic tank is cleaned through inspection hatches. To improve the quality of cleaning, biofilters are installed in the second chamber. These elements look like cylindrical brushes. Gradually, solid particles of waste accumulate on their bristles, so the filters must be cleaned periodically.

The biofilters of the Krot septic tank are made in the form of a round brush; they are not difficult to remove for cleaning. A manual valve allows you to switch the operation of the device to remove purified water using a pump

Biofilters are installed in the septic tank in such a way that they are easy to remove and put back in place. Therefore, cleaning filters comes down to a number of simple steps: remove the brush from the septic tank, carefully shake off the dirt back into the container and put the cleaned filter back in place.

This simple principle of operation and the simple design of the “Mole” septic tank allow you to achieve very modest results. The degree of wastewater purification here reaches only 60%, which is noticeably lower than that of more technologically advanced VOCs, which demonstrate almost 98% purification.

And yet this is noticeably higher than the quality of wastewater treatment in a conventional cesspool with overflow. If you want to improve the quality of waste processing, you can supplement the “Mole” septic tank with a compressor.

This will allow aeration of the wastewater inside the septic tank and effectively use aerobic bacteria along with anaerobic microorganisms to treat the wastewater. The manufacturer equips the septic tank with such a device and provides space in the design for their installation.

Another interesting addition to the “Mole” septic tank is the so-called composting module or K-module. It is installed in the first chamber of vertical septic tank models and serves to collect the insoluble part of the wastewater, which can later be composted, i.e. use as fertilizer.

The contents of the K-module must be periodically removed and buried in the ground, where this waste will be processed naturally.The K-module is produced in the form of two separate sections of 29 and 50 liters or in the form of one large container with a volume of 150 liters. In the first case, the K-module should be removed and washed from the hose manually.

There is no need to remove the large K-module from the septic tank for cleaning. Its contents are pumped out using a pump; there is no need for rinsing. If a family of three or four people uses a septic tank, the K-module needs to be cleaned approximately once every three months.

The wastewater that has settled in the septic tank cannot simply be dumped onto the terrain. They need to undergo a soil tertiary treatment system in an absorption well or on a filtration field (+)

Advantages and disadvantages for comparison

Speaking about the advantages and disadvantages of Krot septic tanks, first of all, buyers note its exceptionally low price for this type of device.

If we compare “Mole” with more expensive ones autonomous treatment facilities, it is worth mentioning another important fact - this device is non-volatile, i.e. for its operation you do not need to connect the septic tank to electricity. Of course, except in cases where the kit is supplemented with a compressor.

Almost all septic tanks that use aerobic bacteria and the aeration necessary for their normal functioning must be constantly connected to the power supply. In areas where power outages occur frequently, this can cause many problems.

If “Mole” is installed on the site, you simply don’t have to worry about it. The manufacturer willingly supplies the device with additional options that allow you to adapt the septic tank to specific operating conditions.

The possibility of installing a check valve, a drainage pump for forced removal of purified water, a shelf for installing this device, another inlet pipe into the second chamber for gray waste, protection against floating, etc. was already mentioned.

This table allows you to get an idea of ​​the cost of various models of the Krot septic tank and the possibility of equipping them with additional options

If you decide to install such a septic tank, it makes sense to think through these points and discuss the option of additional equipment with the supplier. The price of the product will, of course, increase as a result, but the septic tank continues to compete in this area very confidently with its analogues.

The next fact that speaks in favor of “Mole” is simple editing. All you need is a foundation pit, no concreting or other “wet” work is needed, and you don’t even need a concrete slab at the bottom to secure the septic tank. Although it should be remembered that the pit for a vertical model will need to be quite deep, a horizontal septic tank is even easier to install.

Durability is another plus. The material itself, the welds that connect the structure, and the stiffening ribs are all made to a high quality level. The service life of the container is estimated at 40-50 years, which is very decent for such an inexpensive device.

“Mole” septic tanks are often characterized as non-floating. What does it mean? The design of the device is thought out in such a way that, after installation, it effectively resists both soil pressure and the effects of groundwater, even with a noticeable increase in their level.

In areas where this indicator is consistently high, it is strongly recommended to use a special protective mount against floating. The word “fastening” in the name of this element evokes associations with the process of attaching the device body to a concrete slab at the bottom of the pit.

In fact, this weighting element is designed to be installed directly on the body of the device. The weight of the body increases, which prevents the septic tank from floating up. According to reviews, the solution found by the manufacturer turned out to be quite effective, despite the fact that the device is not attached to any static object.

Septic tank maintenance has been simplified as much as possible. The design provides access to the inlet and outlet pipes so that they can be quickly cleaned in case of blockage.

The process of cleaning biofilters has already been described above and is also extremely simple. If the cleaning efficiency has decreased, the biofilters can simply be washed in clean water to correct the situation.Annual removal of silt deposits will not cause big problems.

This diagram allows you to get an idea of ​​the features of installing a “Mole” septic tank in areas with a high level of groundwater (+)

At the same time, the buyer does not have to count on a high degree of wastewater treatment. Even when installing the compressor The manufacturer does not guarantee any high results. Therefore, the contents of the septic tank after processing cannot be used immediately as fertilizer.

It is recommended to remove it or place it in compost heaps for further processing. The water obtained as a result of settling and processing of wastewater will also not become clean enough for irrigation or to meet technical needs on the site.

In addition, the design does not provide a separate storage tank for purified water, therefore, when installing a “Mole” septic tank, an absorption well or filtration field must be created for additional purification and removal of water into the ground.

Features of installation of these septic tanks

Installing a “Mole” septic tank looks quite simple compared to more expensive analogues. The dimensions of the device are small, so choosing a suitable place will not be difficult. After this, you need to mark the pit and dig it. The length, width and depth of the pit should exceed the same parameters of the container by approximately 20 cm.

After the pit is ready, its bottom is leveled and a sand cushion 15-20 cm thick is laid on top. Now you can carefully lower the septic tank inside and connect the sewer pipes from the house to it and from it to the filtration field.

In small areas, field construction for soil post-treatment is often impossible. In such situations, another device should be made separately - a drainage well, also known as an absorption or filtering well.

Sand is placed at the bottom of this structure, then crushed stone and/or gravel. The total thickness of the backfill is at least 1 m. This is a filter for post-purification of water discharged from the septic tank.

From the house to the septic tank and from the septic tank to the drainage well, trenches are laid for laying sewer pipes. If a separate pipe is used to drain gray waste, another trench can be made for it. It is recommended to insulate the pipes to prevent them from freezing in winter.

Communications must have a slight slope so that the liquid moves through them by gravity. The size of the slope is 2 - 3 cm per linear meter.

The sewer and drainage pipes are connected to the corresponding pipes of the septic tank. Installation of additional elements, for example, a drainage pump, can be done before and after installing the septic tank in the pit.

After the septic tank is installed in the pit, the space between the walls of the device and the soil is filled with sand. First, the septic tank must be filled with water.

Now you need to sprinkle the device with sand. There is no need to add cement or other binders to the sand. First, the container is filled with water to compensate for the external pressure. Then the free spaces around the body are filled with sand. After filling is completed, the water is removed from the container, the septic tank is closed with a lid and its operation is checked.

The space around the lid is covered with soil. If desired, the cover can be decorated to improve the condition of the landscape on the site.But it should be remembered that the internal contents of the septic tank need free access for regular maintenance of the device and necessary repairs.

In small areas, instead of a filtration field, filter wells are installed. It should be remembered that all soil tertiary treatment systems can be installed only if sandy soils predominate on the site. The second mandatory condition: there must be at least 1 m between the conditional bottom of the soil system and the groundwater level

He will introduce you to the full range of work on the construction of an autonomous sewerage system on a suburban area. next article, in which all stages are analyzed in detail.

Conclusions and useful video on the topic

This video clearly shows the process of installing a vertical septic tank “Mole” with a volume of 2400 liters and five infiltrators for discharging purified water:

Here you can see the installation procedure for the horizontal septic tank “Mole”:

And this short video demonstrates the resistance of the “Mole” septic tank to floating:

Septic tanks “Mole” are a reliable and relatively inexpensive device that will be a real boon for many private households. Of course, its efficiency is significantly lower than that of some popular VOCs, but an almost 100% degree of purification is not always necessary.

The simple design and high-quality execution minimizes possible breakdowns and ensures stable operation of the autonomous sewage system created on its basis.

Would you like to talk about how you installed a Krot septic tank or a similar treatment plant on your own country property? Do you have information that would be useful to site visitors? Please write comments in the block below, ask questions and post photos on the topic of the article.