Filter wells. Filter well: example of self-design

In a private house quite remote from the city there is usually no central system sewerage. But there is wastewater, which is a product of human activity, and it needs to be disposed of somewhere.

Often this is an ordinary sewage pit, which is fundamentally wrong and leads to contamination of the soil and groundwater. The best solution The issue is the arrangement of a septic tank with a filter well, which we will consider in this article.

General provisions

First of all, let's get acquainted with the functionality of such a device and its alternatives.

Functions

The filter well has the following purposes:

Filtration waste water, which comes out of the septic tank after the preliminary stages of cleaning. The process is carried out using a bottom filter located at the base of the structure.

Advice: if we are talking about a dacha where you do not live permanently, and its volume of wastewater does not exceed one cubic meter per day, then you can get by with one well cleaning without a septic tank. This will significantly save your budget.

Creation of a garden irrigation system. Ultimately, if the technology is followed, the liquid has a sufficient degree of purification to be used as irrigation plant crops.
Localization of pollution. The wastewater will not spontaneously spill over the site, but will end up in a strictly designated place for it.

Alternatives

It should be noted that this is not the only way to purify water after a septic tank.

Also used:

Absorption trenches. Low price, but the level of cleaning is poor and a lot of space is required.
Sand and gravel filters. Poor localization, there is a possibility of dirty liquid getting directly into the ground.
Underground filtration field. After several years of using this option, it is necessary to transfer the entire sewer system to another location due to the unsuitability of the soil for further cleaning.

Using a well, although it requires some moderate costs and labor for its creation, is at the same time the most rational structure for purifying waste liquid.

Installation

It is not at all difficult to build a filter well with your own hands; it does not require any construction or engineering skills. But you need to know general ideas and some nuances.

Selecting a location

There are several conditions that must be observed during the construction of treatment wells to ensure their effective and harmless operation:

Depth of groundwater. There must be a distance of at least one meter between the bottom of the structure and the water.
Presence of a water well on the site. The maximum distance between these objects is required to avoid contamination of the aquifer.
Soil type. Sandstone, sandy loam and peat are quite suitable. Clay, for example, is not suitable for its structure as a filter.

You should know: the size of the well area directly affects its service life. Since a large filter gets dirty more slowly than a small one.

Arrangement

The following instructions will help you do everything correctly:

We dig a pit, the main condition for which is to deepen it below the freezing level of the soil and maintain a distance from groundwater of at least 100 cm. We select the dimensions based on the amount of daily wastewater flow.

Create a bottom filter. This is the most important element, which performs the filtering itself.

To do this, we fill in a meter-long layer of granular loading, in the form of which the following are suitable:

gravel;
crushed stone;
expanded clay slag;

We punch a hole to the septic tank at a level no lower than fifteen centimeters from the bottom filter material.
We connect the structures with a sewer pipe.

Tip: a board shield should be installed under the pipe. This will promote uniform distribution of liquid throughout the bottom and prevent washout.

We are building walls. In this case, their surface should have holes with a diameter of 5 cm and in increments of 10 cm in a checkerboard pattern.

Materials suitable for this task:

Brick or a natural stone . On the one hand, it is easy to create the necessary holes, on the other hand, brickwork is a very labor-intensive task.

Tip: When using bricks, choose only well-fired products. Silicate samples, being constantly in water, will quickly become unusable.

Barrel from of stainless steel . Durable, easy to install, but expensive and limited in area - it is not easy to find a sample with a sufficiently large diameter.

Concrete rings. Practical, reliable, affordable option. Such filter wells are most widespread.

In the ceiling we install an exhaust pipe with a diameter of 10 cm and a height above the ground of at least 30 cm. We equip its outlet with a special umbrella to protect it from precipitation.
To gain access inside, we install a hatch with two covers: a load-bearing one and an insulating one. The recommended diameter for them is 70 cm. Between them we lay insulating material, which can be mineral wool, extruded polystyrene foam or felt.

We fill the gaps between the walls of the structure and the ground, which should be about half a meter, with the same material that we used to create the bottom filter.

Good afternoon, dear forum users!
I have a problem that I am asking for your help in solving.
After 6-7 months of operation, the filter well at the septic tank became clogged, the water flows poorly, I can guess why. It is not very clear what to do to normalize the sewage system and avoid a similar problem in the future.
Available:
A sewerage scheme for a septic tank “Tank 2” + a filter well has been implemented. The level of groundwater level is unknown, but the house (and the site) is located on a hill; according to the experience of operating the septic tank, the arrival of water from the outside into it was not noted. The soil where the well is installed is sandy loam or loam, but definitely not clay.

The filter well consists of three reinforced concrete rings, installed one on top of the other and fastened with brackets for strength. There is no bottom; the bottom is filled with gravel at a level of 30-40 cm. Gravel of various grain sizes. The pipe entrance from the septic tank is made in the upper ring at a depth of approximately 80 cm from the top edge of the well. From above, all this is covered with a plastic lid, which has stiffening ribs, thanks to which the lid does not fit tightly and ensures some air flow into the well.

The bacteria “Doctor Robik” DR37 was initially poured into the septic tank (when it was put into operation). When starting a septic tank - half a bottle and after a couple of months another half. It is written on the bottle that the volume of the bottle should be enough for a year of operation of the septic tank. Later, when the water began to flow poorly and doubts arose about the operation of the septic tank, I added more bacteria, now I don’t remember the brand, also imported. That is, I only poured bacteria into the septic tank three times in eight months, maybe it should be more often.

Our water consumption is mainly for three people. Washing dishes, doing laundry three to four times a week, showering every day in the evening (on average 2 people). Consumption is approximately 200-250 l. per person per day. The pit has to be pumped out every three to four days, rarely- once every five days.

For a month or two after launch, the system worked like clockwork, even a whole bath of water was drained painlessly, then we bought a st. machine, began to use it and little by little the water began to drain worse and worse, to the presentmoment (8 months after the start of operation) practically does not go away. Or it goes away, but the absorption capacity of the well lags far behind the inflow from the septic tank

"Vigorous" household chemicals(Domestos, Colgates, etc.) we don’t use. Art. Ariel powder, gentle dishwashing detergent. For the bath - soap (although Safeguardwe use) and shampoo.

Using a regular board, I checked what was going on in the septic tank and at the outlet of the pipe in filtration well: in the septic tank itself there are no solid and large fractions, very cloudy (with a lead tint) and soapy water without a strong odor, at the bottom of the sediment in the form of a continuous layer is not felt, only a light suspension. Under the pipe in the well I hung a bucket with a holey bottom filled with sand overnight - within a day the sand becomes washed out so that water stops flowing through the bucket. A gray oily crust of a centimeter forms on top of the sand. two.

Question: does the septic tank work (does it clean the wastewater) and is the filter well made correctly? What needs to be fixed to resolve this issueand avoid its repetition in the future?

I apologize in advance for this stream of consciousness, but I want to somehow change the situation. Thanks in advance for any help.

An autonomous sewage disposal system is an indispensable part of the infrastructure of the garden plot of any private home. The methods of its construction can be completely different: from connecting to utility networks common use, before creating our own innovative wastewater treatment system. An intermediate position between these two extreme options is occupied by a filter well.

What's happened ?

Unfortunately, most residents of private houses in our country are not aware of the existence modern systems autonomous sewage treatment. The experience of building an ordinary cesspool, which is a container buried in the ground, is passed on from generation to generation.

And it’s good that it’s a container, because it could very well be an ordinary pit without sealing the walls. But with the slightest mistake in choosing the location of the cesspool, with unplanned movements of the soil or a sharp rise in the groundwater level, sewage from the classic cesspool immediately ends up in unplanned places.

It’s okay if this place is just the surface of a personal plot. It is much worse if the sewage is within reach of the water intake system. This can lead to big environmental problems.

But ordinary cesspool it is quite possible to modernize it so that it begins to play a role, albeit not very effective, but still treatment plant. We are talking about filter wells, which advantageously combine the low cost of construction (slightly more than classic cesspools) and sufficient effective system wastewater treatment (slightly less than entry-level septic tanks).

How does a filter well work?

Let’s say right away that a filter well can guarantee you the purification of no more than one cubic meter of sewage per day. However, such equipment is quite easily scalable - just build several more filter wells at some distance from each other and the volume of wastewater they purify will increase significantly.

In addition, the filter well can be used in conjunction with other water treatment facilities. For example, it can be placed as additional equipment when installing septic tanks, and partially purified sewage from septic tanks will undergo additional treatment in a filter well. After passing through the septic tank and filter well, the sewage will be so clean that it can be freely discharged directly into the ground.

By the way! The name “well” indicated in the description of this hydraulic structure is quite arbitrary. Drainage and absorption trenches, a filtration field located underground and other similar structures can have the same purification effect.

Conditions for constructing a filter well

Unfortunately, a filter well cannot be built on any site. The most critical factor in the placement of filter wells is the groundwater level and the presence of an aquifer near the treatment structure. In any case, the level of the aquifer should be located no higher than the bottom of the filter well, no closer than a meter from it.

In addition, the composition of the soil on your site has a certain influence on the choice of where to build a filter well. It would be most optimal to place the filter well on sandy soils and sandy loams; peat also has excellent filtering functions. But if your site has a deep layer of clay soil, it makes no sense to place a filter well on it.

Before designing a filter well, pay attention to the area of its bottom, which also differs depending on the composition of the soil on the site. So the filtering sand bed can be at least three square meters, and on sandy loams such a bed can be one and a half square meters.

When creating a filter well in sandy soils, to prevent the walls from collapsing, they can be lined with brick or stone.

Another factor influencing the construction of a filter well is the depth of soil freezing in your area. For a well to operate effectively in winter, it is necessary that its bottom, even in the harshest winters, is guaranteed to be located below the soil freezing line. For Russian regions located in middle lane, this value is approximately one and a half meters.

Basic design of a filter well

Most the best option The design of the filter well will be located after one settling chamber. This scheme is perhaps the most reasonable from the point of view of the price-quality ratio.

With this method of device autonomous sewerage The wastewater is first directed through a single pipe into a concrete well with a bottom, which is a sump. In the settling tank, the wastewater is at rest and, as a result, light fractions of contaminants and gases dissolved in water float up, and heavy fractions of contaminants settle to the bottom of the tank. Approximately in the middle of the height of the settling well, an overflow pipe is installed, which takes the settled wastewater into the filter well. Purified wastewater is directed into the ground through a filter well.

For such a system, a filter well is installed with walls consisting of reinforced concrete rings. The total depth of such a structure can reach three meters, but the maximum depth should be at least a meter higher than the maximum groundwater level in your area.

As already mentioned, several filter wells can be built on the site. When designing their location, it is necessary to choose a place so that between the heads of the well shafts there are at least two diameters of the wells.

Choosing filter materials for a well

The most popular materials for creating a filter pad in a drainage well are segments of peat bog, medium-sized crushed stone, fragments of bricks, coke, slag fractions and similar materials. It is necessary to pay attention that the largest fraction in the filter pad should not exceed 3 centimeters.

With constant operation of the filter pad, activated sludge forms on it. It consists of colonies of microorganisms, which, in the course of their life activity, process organic residues into elementary chemical substances. This ensures additional cleaning of the sewage flowing into the well.

General principle The operation of the filter well looks like this:

First, a filter pad made of crushed stone of small fractions is placed at the bottom of the well, then brick fragments and slag are placed on top of it;
Backfilling between the walls of the pit and the walls of the well is also made with a material of similar composition;
In addition, the layer of soil located under the bottom of the filter well also cleans the incoming sewage.

How to choose the shape and material of the filter well walls

In principle, the shape of the filter well can be any, but it is desirable that it be round - this will ensure a more uniform distribution of pollutants throughout the volume of filtered wastewater.

As for the material for making the walls, the most optimal are the following building materials: red brick, monolithic concrete or reinforced concrete structure, clay brick. One of the most popular materials is ready-made.

How to build your own filter well

Let's consider the procedure for constructing one of the most popular modifications of a filter well. Such a structure is formed from ready-made reinforced concrete rings.

Step 1

We choose a place to build a filter well. Since it will have direct contact with the ground, we place it away from water sources. Please note that over time, the thickness of the filter pad may form a large number of sediment that will have to be pumped out with a sewer truck, so provide a place for transport access.

Step 2

We dig a pit to the diameter of the finished reinforced concrete rings. It can be done mechanically using an excavator or manually. In order to dig a shaft for concrete rings manually, you must proceed as follows:

install the first ring in place of the future well;
start digging inside the ring, throwing the earth out;
under the influence of its own weight, the ring will sink into the ground;
After the first ring has sunk into the ground, a gasket with holes is installed. This could be, for example, bricks. The holes will ensure that relatively purified wastewater from the liquid layer goes into the ground;
the second ring is installed and the digging of the pit continues.

Step 3

We place a sewer outlet pipe or an overflow pipe leaving the septic tank in the filter well. In any case, such a pipe should be approximately 10 centimeters higher than the upper surface of the filter pad.

Step 4

We place a filter pad at the bottom of the well. We use a similar composition to backfill between the walls of the pit and the walls of the well.

By the way! Practice shows that the best option would be to place a filter element with a larger fraction in the center of the well, and smaller ones closer to the walls. The outlet of the sewer or overflow pipe must be located in the center of the well so that the incoming waste falls onto crushed stone with a coarse fraction.

Step 5

A ceiling is placed on top of the filter well. It can be produced using ready-made reinforced concrete slab or using durable wooden planks. If you want to use the filter well around the clock, then it would be reasonable to equip it with two covers, between which place a layer of thermal insulation. Can be used as a heat-insulating layer mineral wool or sheets of foamed polymer.

To ensure equipment maintenance, an inspection hatch with a cross-section of at least 70 centimeters is placed in the ceiling.

The remaining space is filled with soil also to provide thermal insulation.

In the ceiling of the filter well it is necessary to provide for the installation ventilation pipe, the upper end of which should be located approximately a couple of meters above ground level. In this way, they will be removed from the well unpleasant odors. In order to make the head of the filter well more attractive appearance it can be disguised as a garden bed or under alpine slide.

As you can see, even with minimal technological skills and a small set of building materials you can install a filter well on your own personal plot. When combined with a settling well, it can very well play the role of a full-fledged autonomous sewer system.

If you watch the video tutorial attached to the article, you will be able to familiarize yourself in more detail with the procedure for constructing filter wells.

Video - Filtration well

Water is an important issue for private home owners. This can be solved using a septic tank or filter well. The latter option requires less construction costs and is more acceptable for many. Such a system allows water that has already been purified from contaminants to pass into the soil.

Description

It is a container with special elements for cleaning. The first stage of wastewater purification is a filter that collects large contaminants. Next, microorganisms that live in the sludge that has formed on the internal surfaces come into play. Often, such systems are installed in addition to a septic tank and provide complete wastewater treatment.

Despite the versatility of the filter, it can only be installed if groundwater lies at a depth of at least 2.5 meters. If this rule is not followed, the contaminated liquid will enter the aquifer. The soil itself must contain a large amount of sand to allow drainage to pass through quickly.

Average daily water consumption determines the number and size of wells. The total volume should be several times higher than consumption. As additional measures biological filters and special trenches are used for purification; the latter are often designed to drain treated wastewater into nearby water bodies.

Varieties

The factory analogue of this design is a filter cartridge whose main purpose is to clean rainwater from oil refinery products, fine suspended matter and heavy metals. It can have different sizes and is usually made to order. Such a device can be used in transport parking lots, in cottage villages and campsites. The design consists of a plastic container, a grid and a non-woven material covering the upper part and the main part, consisting of absorbent material. Treated wastewater is safe for environment and are suitable for discharge into water bodies.

Sanitary standards

The first stage of arrangement is the competent choice of location. Special attention is paid to sanitary requirements, in accordance with which:

The filter well for the septic tank is located 2-4 meters from the neighboring territory.
The construction of such a structure is prohibited near wells and other sources of drinking water. The minimum distance is 30 meters. With high soil permeability, this parameter increases by 20 meters.
The distance between the well and residential buildings must be at least 10 meters.

Filler

The dimensions of the structure depend on the intensity of the runoff and the type of soil; most often, the diameter of the upper part is 2 meters. The filter depth is selected individually and ranges from 2-3 meters. It is undesirable to dig a filter well with a depth of more than 3.5 meters, as this will complicate cleaning and may speed up the need to create a new septic tank.

It is possible to use any environmentally friendly filter media. The most popular are slag, crushed brick, peat, and crushed stone. It is recommended to use material with a fraction of no more than 3 cm. The best option would be a combination of several types of fillers. For example, fine slag is placed at the bottom, and crushed brick acts as the top layer. In this case, organic waste will remain on the top layer and be processed by microorganisms living in the sludge. After which the wastewater will undergo additional purification with slag and end up in the soil layer.

Basic moments

A filter well for sewage can have different shapes, for example, rectangular or round, which depends on the materials used. Wall construction is possible using car tires, reinforced concrete products, concrete or brick.

First you need to dig a pit. Its dimensions are selected in accordance with the intended design and with a margin of 30-40 cm. Arrangement of walls does not require special skills. When using bricks, it is recommended to lay them with holes about 4-5 cm wide to prevent water from stagnating.

To build a well from concrete rings, you can purchase ready-made products or find used rings with natural holes, significantly saving your budget.

The process of installing products can be simplified by installing a ring in place of the intended filter and gradually removing soil from the inside. The ring will gradually sink into the ground under the influence of its own weight. It is also necessary to proceed with the remaining products, laying them on top of each other.

Before arranging the walls, it is necessary to determine in advance the point of release of the septic tank or sewer drain. In this case, the pipe outlet must be located at a distance of at least 20 cm from the level of bulk material. It is also recommended to select a piece of wood suitable size to place under the area where the jet hits. This will improve the quality of treatment and ensure uniform distribution of wastewater.

It is poured only after the completion of the walls. According to experts, optimal solution will be filling fine-grained material along the edge of the bottom and filling the center with more large material. Backfilling is necessary not only for the bottom, but also for the free space between the walls of the pit and the filter.

Completion

The upper part is covered with a shield made of reinforced concrete or wood. This should leave room for the ventilation hole and hatch. The last element is invaluable, since it is used to carry out preventive inspection and, if necessary, cleaning of the bulk layer. A well with a filter load must have a hatch with dimensions of at least 70 cm to ensure free access. It is best to use a double construction with insulation. The location of the ventilation hole can be any. Finally, the upper part is covered with roofing material pressed down with soil. In order to prevent freezing in the winter months, you need to make a thicker layer - at least half a meter. Unsightly appearance can be decorated with any elements landscape design, flower bed, For example.

Plastic analogues

Plastic filter wells have become quite widespread. Their arrangement is more expensive than a septic tank made from scrap materials, but they have many advantages. Among the main ones, it is worth highlighting quick installation, reliability and simple maintenance. The volume of the container can vary widely, so it is selected in accordance with the approximate daily water consumption. The tank is based on a layer of filter material; the walls are made of durable plastic that is not subject to corrosion and has a long service life. Manufacturers offer a wide range of plastic containers, which greatly simplifies the choice.

Tire usage

The most budget option is a filter well made from used car tires. His bandwidth quite enough for a family of three. Most often, such systems are installed in houses used only for living in summer months, since the material is susceptible to freezing, which reduces the vital activity of bacteria or completely stops at abnormally low temperatures.

Creating such a design does not require special skills - just put the tires on top of each other and secure them with plastic clamps. The joints are sealed with a special compound. Manufacturing the upper part of the structure and filling the material are carried out in exactly the same way as when creating wells from other materials.

Care

A well with a filter cartridge requires systematic maintenance, which consists of timely removal of sludge and cleaning of large contaminants. Before cleaning, it is necessary to stop operating the sewerage system for a while to reduce the level of wastewater in the tank. After which you need to partially replace the bulk layer and thoroughly loosen it.

In case of heavy siltation, apply special means, which are also recommended to be used to maintain cleanliness. They have different prices, depending on the volume and manufacturer. Before adding the drug, the filter well is emptied using a sewer machine, after which the product dissolved in hot water is poured.

An autonomous sewage disposal system is an indispensable part of the infrastructure of the garden plot of any private home. The methods of its construction can be completely different: from connecting to public utility networks, to creating your own innovative wastewater treatment system. An intermediate position between these two extreme options is occupied by a filter well.

What is a filter well?

Unfortunately, most residents of private houses in our country are not aware of the existence of modern autonomous sewage treatment systems. The experience of building an ordinary cesspool, which is a container buried in the ground, is passed on from generation to generation.

It’s okay if this place is just the surface of a personal plot. It is much worse if the sewage is within reach of the water intake system. This can lead to big environmental problems.

But an ordinary cesspool can be modernized so that it begins to play the role of a treatment facility, albeit not very effective, but still. We are talking about filter wells, which advantageously combine the low cost of construction (slightly more than classic cesspools) and a fairly effective wastewater treatment system (slightly less than entry-level septic tanks).

How does a filter well work?

By the way! The name “well” indicated in the description of this hydraulic structure is quite arbitrary. Drainage and absorption trenches, a filtration field located underground and other similar structures can have the same purification effect.

Conditions for constructing a filter well

When creating a filter well in sandy soils, to prevent the walls from collapsing, they can be lined with brick or stone.

Another factor influencing the construction of a filter well is the depth of soil freezing in your area. For a well to operate effectively in winter, it is necessary that its bottom, even in the harshest winters, is guaranteed to be located below the soil freezing line. For Russian regions located in the middle zone, this value is approximately one and a half meters.