Filter well and method of soil post-treatment of wastewater. Filtration well and its principle of operation

Very often, residents of remote villages, when organizing their lives, do not have the slightest idea of ​​how to do it correctly. In particular, when it comes to the construction of sewage systems in the house and on local area They can’t think of anything other than an ordinary hole in the ground into which a pipe is thrown. But in vain! After all, it is quite obvious that dirt and harmful substances seep further into the soil and reach groundwater, namely they are the source drinking water in the private sector, since it is with them that wells and boreholes are filled. To solve such problems, civil engineers long ago came up with an excellent “joke” - a filter well.

In fact, we are talking about an independent water treatment and drainage facility, the relevance of which comes in a situation where the volume Wastewater in a specific area does not exceed 1 cubic meter. per day. If the specified standards are exceeded, then the filter well is used as additional means for wastewater treatment, used at the second stage of treatment after the septic tank. That is, in fact, the method is produced soil purification wastewater, which will then be discharged into the ground.

Note! Naturally, not only a filter well can be used as an auxiliary structure for purification and drainage. It would be absolutely adequate to make an absorbent trench, sand and gravel filter or underground filtration fields.

In order to choose the most correct type of treatment plant for specific conditions, it is necessary to take into account whole line conditions:

1. Ground water level.
2. Presence of an aquifer.
3. Presence of a traditional well.
4. Soil type.

Filter well design and depth standards

It may very well be that, under certain circumstances, installing a filter well is completely impossible. Then the situation will have to be resolved based on the current realities. But if all objective and subjective conditions favor the use of this particular cleansing element, then the following question will be quite logical.

In what part of the site is it better to locate it?

The installation of a filter well can be easily done on soils that are suitable for filtration:

• sandy;
• sandy loam;
• peat

If you try to build such a filter in clay soil, then most likely it will not take root there. An important characteristic of a filter well is the filtration area, which can be equal to an indicator in the range of 1.5 square meters. m (sandy loam) – 3 sq. m (sand).

Attention! The larger the filtering area of ​​the well, the longer its service life will be.

As an option, build the walls of the filter well from bricks

In order for this purification facility to fully cope with the tasks assigned to it, it must be located in an area where groundwater lies below the level at which the filtering bottom of the well, which is a cushion of crushed stone, is located. Moreover, the distance from the water to the bottom of the treatment facility must be at least 0.5 m. The base of the well itself must rise above the groundwater level by 1 m. If a high groundwater level is recorded in the territory, then it is also better to abandon the construction of a filter well.

Important! This sewer element must be located below the soil freezing level. If we take the region of central Russia, then this value will be equal to 1.3-1.4 m.

Correct device and standards

A well is made without a bottom, that is, only walls, and even those have holes. At the bottom of the structure, a decent thickness of a layer of granular loading is placed, which is called “ bottom filter" The water, having been purified from various suspended particles in the septic tank, is discharged into the well. Here it is also worth emphasizing that the pipe through which water from the septic tank enters the filter well must rise above the surface of the bottom filter by at least 0.15 meters.

In the place where the stream falls on the surface of the filter, an antiseptic wooden shield is laid, designed to ensure uniform distribution of wastewater over the well area. This protects the backfill from erosion. The loading is about 1 m high and is made from the following materials:

• crushed stone;
• gravel;
• small pebbles;
• expanded clay;
• brick fight;
• sintered slag;
• fragments measuring 10-70 mm.

Holes about 5-6 cm in diameter are punched in the walls of the filter well, along the entire length and height in a checkerboard pattern at a distance of 10 cm from each other. External part sprinkled with the same material that was used to create the load. In this case, the width of the outer layer should be 40-50 cm, and the height should correspond to the loading height.

Depending on the required diameter, the number of bricks for masonry is calculated

The walls themselves treatment plant this type can be made from various materials starting from ordinary old metal barrel and ending with such elements as reinforced concrete rings for a filter well. In addition, it is quite justified to line the walls of the well with round or square bricks (half a brick) or natural stone. The most important thing when laying is to leave technological gaps or already drill holes in finished product.

In a situation where it is obvious that the filter well is in accordance with necessary requirements and according to preliminary calculations it will occupy a significant area (more than 4 sq.m. with a depth of 2.5 m), it would be more reasonable to construct not one huge well, but the construction of several small ones, which will be dispersed throughout the site.

Remember! Wastewater must be removed as far as possible from the source of drinking water, at least 30 m.

Similarly, like a septic tank, a filter well needs a ventilation pipe. It is installed in the ceiling, and the top of the pipe must be on the surface of the ground and be equipped with a weather vane. The most optimal diameter of such a pipe is considered to be 100 mm. If the pipe does not fit well into the surrounding landscape, then it can be disguised climbing plants or otherwise adapt to stylistic decision local area.

The ring option is currently becoming the most popular due to the low labor costs

In the well ceiling there is a hatch with two covers with a diameter of 70 cm. Top cover- load-bearing, and the lower one - insulating. A space is left between the lids, which is filled heat-insulating material, for example, bags of perlite sand or mineral mats.

Underground irrigation fields

Treated wastewater can be used for domestic needs, in particular used for irrigation of a personal plot. For this purpose, a whole system of underground channels or drains is created. The area over the surface of which the water removed in this way spreads is called an irrigation field. Effective use such a system is relevant only for those soils and other operating conditions, as for the filter well.

Option using drainage field- very effective, but not always justified in small businesses

We hope our tips will help you create the right system sewerage on your site. To do this, first make yourself small project, and we have already talked about what points it should consist of.

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 modern systems autonomous cleaning sewerage. 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's much worse if sewage will be 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 will play the role of, albeit not very effective, but still a treatment facility. 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 septic tanks entry level).

How does a filter well work?

Let’s immediately make a reservation 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 easy to scale - just build a few 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, partially treated 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 efficient work well in winter, it is necessary that its bottom, even in the harshest winters, is guaranteed to be 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 wastewater through a single pipe is first sent to concrete well with a bottom that is a sump. In the settling tank, the wastewater is at rest and, as a result, light fractions of contaminants and gases dissolved in the 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 with walls consisting of iron is installed. concrete rings. The total depth of such a structure can reach three meters, however 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 drainage well are segments of peat bog, small 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.

At permanent job activated sludge forms on the filter pad. 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 are ready-made reinforced concrete rings.

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, 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 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 produce with a similar composition 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 boards. 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 of a 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 small set building materials you can install a filter well on your 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

Unlike residents of multi-storey buildings, owners of private households are not provided with a centralized sewerage system and are forced to independently organize wastewater disposal on their property. A filter well plays an important role in the sewer and drainage system of a house.

However, it cannot be installed everywhere; there are certain rules that must be followed when constructing it.

In our material we will understand the types of filter wells, the rules for their installation on the site, and also tell you how to make such a structure yourself.

Environmental and conservation issues environment today they are very acute. Untreated wastewater, if it flows directly into water bodies or soil from the internal sewer system, can serve as a source of contamination of water and soil.

Provided various ways wastewater purification, one of which is an absorption well, which acts as a kind of natural multi-layer filter. It retains dirt, debris and other particles, and allows purified water to flow into the soil.

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A distinctive feature of filter structures is the absence of a sealed bottom. A bottom filter made of crushed stone, gravel, broken brick and other similar building materials is equipped at the bottom of the well. Overall height filter filling should be up to one meter.

A filter well is usually installed in areas that are not equipped with a drainage system, as well as in places where there are no natural reservoirs nearby for water drainage.

It can be used as an independent structure when arranging drainage system or, or for post-treatment of wastewater that has undergone preliminary treatment in a septic tank.

The function of a filter well is to pass the liquid entering through the pipes through natural system filters and discharge already purified water deep into the ground

Installation rules and regulations

The capabilities of filtration wells are very limited; the rules and features of their installation are regulated building codes (SNiP behind the number 2.04.03-85 ).

They can only be installed on certain types of soil: sandy or sandy loam, which themselves have good absorption capacity. Absorption wells are not suitable for clay soils with low filtration properties.

For comparison, if 1 m² of medium-sized sand can absorb up to 80 liters of liquid per day, and sandy loam - up to 40, the absorption capacity of loam is 25, and fractured clay - only 5 liters. From the given data it follows that when installing a filtration well on clay soil, it will, of course, purify the water, but there will be nowhere for it to go.

When arranging a filtration well, you need to find out what kind of soil is on your site. The structure cannot be built in soils with high and medium clay content, which cannot ensure good fluid outflow

To find out the type of soil in the area, do the following experiment: dig a small hole measuring 300x300 mm and about 150 mm deep. Pour liquid into it to the very top and note how long it takes for the water to go underground. 18 seconds – sandy soil, half a minute – sandy loam, 2 minutes – loam.

Particular attention should be paid to the groundwater level in the area. If The groundwater pass quite high, it is not recommended to install an absorption well, since its depth should be 2-2.5 m. In this case, it is necessary to ensure a distance of at least one and a half meters from its bottom to groundwater.

Installation restrictions also apply to the average daily volume of wastewater. Their number should not exceed 1 m 3 . If the volume of wastewater to be treated is larger, it is recommended to choose a different filtration and liquid removal system.

When planning a house sewer system, you must be guided by established location standards treatment system from the source of drinking water and the boundaries of the site

If underground water is used for drinking or household needs, the construction of a well must be coordinated with the sanitary and epidemiological inspection services. But in any case, it must be done at a distance of at least 30 meters from wells and wells for drinking water. You can read about the features of installing a sewer pipeline on the site.

Construction regulations the rules governing the location of the conditional bottom of the filter well are specified. It must be 1.5 m or more above the groundwater horizon.

The conditional “bottom” of the filtering sewer structure must be located above the groundwater horizon at least one and a half meters higher

Types of filter structures

There are two types of well filtration structures that work on the same principle and are installed in a similar way. Their differences lie in the area of ​​application. The former are used in drainage and storm system, the second - in the sewer.

Absorption well in the drainage system

IN in this case drainage absorption wells are the final destination complex system, where soil or rainwater, so that later, after passing through a natural filter, it goes into the ground. Its main purpose is to remove water from the house and clean it from silt and sand.

The diagram shows the organization of storm and drainage sewerage for a site with a storage tank. In soils with high absorption capacity, instead of a collector, a filtration well is installed

The diameter of such wells, as a rule, is no more than one and a half, and the depth is up to two meters. It is allowed to drain both systems into one well. The filter container is installed at the lowest point of the site so that water flows into it by natural gravity.

Filtration structure in the sewer system

IN sewer system site, absorption wells are used for post-treatment of wastewater coming from a hermetically sealed tank in which the wastewater undergoes primary biological treatment. The tank is made of concrete rings, brick or rubble stone, or a ready-made septic tank is used.

Scheme of installing a filtration well with a septic tank, in which sewage waste undergoes primary treatment, and then flows through a pipe into an absorption tank and through a filter system goes into the soil

The principle of operation of the system is as follows: wastewater from the house sewer enters a sealed container, where it is oxidized under the influence of anhydrous acid for two to three days. aerobic bacteria living in airless space.

Then the wastewater enters the filtration well, where other bacteria - aerobes - are already present. Their vital activity is activated under the influence of oxygen.

As a result of double purification, the liquid entering the soil from the absorption well is almost completely free of harmful microorganisms and organic substances.

Wastewater disposal can be organized in two ways:

1. Separate. Water from the kitchen, bath, washing machines enters the septic tank, and sewage with feces goes into the cesspool.
2. Joint. All domestic wastewater enter or storage tank.

As a rule, in the first case, gray wastewater is sent to different sewerage facilities. For example, fecal - in storage well with subsequent pumping and removal, gray domestic wastewater from kitchen sinks, bathtubs, washbasins, etc. devices - into absorption wells.

In the second case, you need a septic tank consisting of a minimum of , each of which sequentially carries out its own cleaning stage. Fecal matter settles in the first chamber, from where it is periodically pumped out using a sewer truck.

A single-chamber septic tank is usually installed in individual households that have a separate sewage system.

Liquid waste without suspended particles with a minimum amount of impurities enters the second chamber, where it is further purified. After this, the water passes through the pipes into a filtration well, from where, after passing through a natural filter, it goes into the soil.

The second version of the joint scheme is full pumping and waste removal.

Calculation of the number of filter wells on the site

The number of filtration wells depends on the daily water consumption in the house. One septic tank is usually equipped with two to four absorption wells. In turn, the volume of the septic tank should be three times the daily flow of water waste.

If we assume that one person in a private house has 250 liters per day, then for four family members a septic tank with a volume of at least 3 cubic meters is needed. meters.

Load per 1 sq. m. area of ​​the absorption well is calculated based on the type of soil. (sandy - up to 80, super sandy - up to 40 l) If the distance from groundwater to the bottom of the well is more than two meters, the load can be increased by 20%. It is also permissible to increase the load by country farms, where the well is used only in the summer.

Alternative filter units

In addition to the filtration well, aerobic post-treatment of wastewater in natural conditions can be done using:

• ground drainage;
• filter trenches;
• biological filter.

In the first case, wastewater from the septic tank first enters the distribution well, and then is distributed through drains - pipes with slots, laid with a slope into trenches, previously filled with gravel or crushed stone. The top of the pipes is also sprinkled with crushed stone, then with earth and covered with geotextile. Read more about how to correctly calculate the slope of a drainage pipe.

Scheme of organizing soil drainage on the site. Part of the treated wastewater goes into the ground, and part is absorbed by plants

If there is a body of water near the site where purified water can flow, then filter trenches are installed. Drainage pipes are laid in the bottom layer on a gravel bed, which are then covered with gravel and sand. They lay slots on top of a layer of gravel, cover them with geotextile and cover them with earth.

If it is impossible to organize filter fields on the site, install a biofilter. It receives pre-purified water from the septic tank for further biological treatment. As a result of filtration, wastewater is purified to the level of technical water, which then goes into the ground.

The biofilter has an oxygen intake system to activate the activity of aerobic bacteria that oxidize the incoming wastewater.

How to make a filtration well

Absorption wells can be built from baked bricks or rubble stones, but their construction requires considerable effort. Therefore, more often the walls of the well are made of reinforced concrete rings. Today we also received wide use plastic structures. You can make them yourself from plastic pipes or buy ready-made ones.

Option No. 1 - brick structure

The brick structure can be either round or square. Usually round wells are built, which are most convenient to use. The structure for filtering sewage should be buried 2.5 meters into the ground, with a diameter of no more than 2 x 2 meters.

The pit is dug in such a way that between the ground and the outer walls of the well there will be a layer of crushed stone, gravel or broken brick up to 40 cm thick. The height of the backfill is one meter. The walls at the filter level must be water permeable.

To do this, to a height of one meter, the masonry is not made continuous, but with small holes ranging in size from 2 to 5 cm. They must be placed in a checkerboard pattern. After the structure is erected, crushed stone or gravel is poured into the cracks.

When building a well, it is necessary to make cracks in the masonry to allow purified water to exit into the ground.

At the bottom of the structure, a filter layer of crushed stone or gravel is backfilled to a height of one meter. In this case, large fractions of the material are placed at the bottom, small ones at the top. The hole for the pipe through which drainage from the septic tank will flow is made in such a way that water flows in a stream from a height of 40-60 cm.

In the place where water flows, it is necessary to lay plastic sheet to prevent filter blurring. The structure is closed from above with a lid or hatch with a diameter of 70 cm. It is also necessary to make a ventilation pipe in the well with a cross-section of 10 cm. It should rise above the ground by 50-70 cm.

Step-by-step construction instructions drain hole made of brick you will find.

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Option No. 2 – construction of concrete rings

To install a filtration well you will need three reinforced concrete rings. One of them should have holes with a diameter of about 5 cm. You can buy a perforated ring or make holes using a concrete crown. You also need to make a hole for the inlet pipe.

The photo shows and describes in detail the process of installing concrete rings for constructing a well.

It is necessary to dig a pit, the width of which is 40 cm greater than the diameter of the ring. A perforated ring is installed at the bottom of the structure. You don’t have to dig a hole, but only slightly deepen the area where you plan to make a well.

Place the first ring on the ground and select the ground from the inside. Gradually it will fall down under the weight of its own weight. The two upper rings are installed in the same way.

After this, you need to make a bottom filter from crushed stone or gravel up to one meter high and fill the outer walls of the well with the same material to the level of the filter layer. The hatch and ventilation pipe are installed in the same way as in a brick well.

Another option for arranging a septic tank made of concrete rings can be read.

Option No. 3 – a well made from old tires

The most inexpensive way to make a filter well is to make one from used tires. This design can provide filtration of sewage for a family of three. Basically, such a well is made on summer cottages, since in winter the rubber freezes and the activity of bacteria slows down, and at very low temperatures and stops altogether.

The well is made very simply - the tires are installed one on top of the other and fastened together with plastic clamps. The joints are coated with sealant. All other structural elements are made in the same order as in wells made of other materials.

Installation diagram of an old absorption well car tires. The number of tires is calculated based on their size and the required depth of the well

Option No. 4 - plastic filter containers

Today you can purchase ready-made filter wells made of plastic, equipped with everything necessary for effective wastewater treatment. Of course, they cost a lot, but they are reliable, convenient, easy to install and maintain. There are many companies producing such equipment on the market.

For example, the Russian company POLEX-FC, whose products received good consumer ratings. Filter wells are produced in different volumes (from 1200x1500 to 2000x3000 mm), which allows you to select a product based on the daily water consumption of an individual household.

The containers are made of corrosion-resistant durable plastic, the walls of the shaft are made of primary polyethylene. The lower compartment of the tank is covered with biofilm and filled with a filter layer of crushed stone, gravel and slag.

A plastic filter well with a three-stage filtration system provides effective cleaning water from impurities

It’s not that difficult to make a filtration well yourself, but if you don’t want to bother with arranging it and you have the financial opportunity, you can buy a ready-made plastic well.

There are many methods of wastewater disposal in private households, which must be chosen in accordance with financial capabilities. One of the simplest and most efficient structures can be considered a filter well, the operating principle of which is based on the use of the filtering capacity of soils, which allow water to pass through itself and ensure its removal beyond the boundaries of the water-saturated area.

When constructing a filter well, it should be taken into account that it should be located no closer than 10 m from the foundations of buildings and no closer than 30 m from wells used for the extraction of drinking water.

Design features

The area of ​​the filter well largely depends on the type of soil, so 1 sq.m of sandy loam can filter about 50 liters of wastewater per day, and sand, depending on the fraction, can filter up to 100 liters. Based on the approximate volume of discharged wastewater, you can calculate the required area of ​​the filter well, which is the sum of the areas of all walls. It is worth considering that the design dimensions of the filter well should not exceed the dimensions of 2 by 2 m when the installation depth is no more than 2.5 m.

If the area of ​​such a well is not enough for wastewater treatment, then the possibility of installing several filter wells should be provided, the distance between which should be at least two diameters of the structures being installed. When building a well, you need to check the groundwater level, since the distance between the bottom of the filter and the horizon must be at least 1 meter.

Device and circuit

The most reliable in operation can be considered a filter well, constructed with the help of concrete rings lowered into the filter material, in which holes should be made in a checkerboard pattern every 15-20 cm in height. If the walls of the well are made of clay or refractory bricks, then technological openings can be arranged at the expense of masonry gaps.

A filter must be installed at the bottom of the well, which can be made of crushed stone, slag, pebbles, peat or sand. The larger fraction material should be located in the center of the well, and the smaller fraction should be located next to the outer walls.

The outside of the well must be filled with sand or sandy loam, which must be located up to the level of the inlet pipe, the width of which must be at least 0.5 m. The filter material must be evenly distributed in height, the value of the last parameter must be in the range of 1.5-2 meters. To prevent the falling stream of wastewater from washing out the filter, a stone must be laid at the bottom.

The central part of the filter well, as well as when installing any septic tank, must have an air cavity closed from above with a hatch, which must be equipped with ventilation pipe. The diameter of the pipe must be at least 100 mm, and the height must be at least 1 m.

It should be taken into account that the operation of a filter well is unacceptable in the presence of clayey or similar soils that have insignificant absorption capacity. It is also impossible to arrange a filter well when high level occurrence of groundwater.