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Drain hole in a private house with your own hands: how to dig and equip yourself

In small settlements there is no general sewerage system. At the same time, the need for safe collection of sewage in a suburban area is extremely important. A simple solution is a drain pit in a private house. But is it capable of providing comfort and epidemic safety to the household? We will discuss solutions to the problem of wastewater in a suburban area.

The operation of a suburban household is associated with the generation of wastewater. Every homeowner is faced with the task of not so much accumulating domestic wastewater as cleaning it. Moreover, the solution common in rural areas - digging an old barrel or tank under the sewer cesspool - is ineffective.

If the daily volume of wastewater exceeds one cubic meter (1000 l), then the shortcomings of the "barrel" septic tanks will soon manifest themselves as unpleasant odors. Or worse - intestinal infections among households. Finally, a do-it-yourself drain pit from a worn-out keg is illegal in a number of situations.

In a drain pit of two chambers, sewage suspensions settle and sewage clarification occurs much better than in a single-chamber bunker (+)

RF regulations require private homeowners to comply with measures to protect groundwater from pollution by domestic sewage. The Law “On the Sanitary and Epidemiological Welfare of the Population” (No. 52-FZ of March 30, 1999) and “Hygienic Requirements for the Protection of Groundwater from Pollution (SP 2.1.5.1059-01) oblige homeowners to solve the problem of wastewater.

The location of the drain pit in relation to the house and the source of drinking water must be observed. Otherwise there will be infections.

In turn, "Sanitary rules for the maintenance of the territory of populated areas" (SanPiN 42-128-4690-88), "Planning and development of gardening (country) associations of citizens, structures and buildings" (SNiP 30-02-97), as well as " Sewerage. External networks and structures (SP 32.13330.2012) standardize the conditions for the organization and operation of "pit" sewage:

  • distance from the house to the drain pit - from 8 m;
  • distance from the well (spring trapping) - from 50 m;
  • distance from a neighboring household (fence) - from 2 m;
  • deepening of the cesspool capacity is carried out to the level of groundwater, but not more than 3 m;
  • cleaning is carried out upon filling, but at least once a year.

Please note that the condition for the distance from sources of drinking water is valid regardless of where these sources are located. Those. Whoever the nearest well turns out to be - yours, neighborly or public - it is permissible to arrange a cesspool strictly 50 meters from it. Otherwise, there will be expenses for fines, reconstruction of the cesspool to a two-three-chamber septic tank and restoration of the ecological balance in the soil.

Cesspool volume

Homeowners need to decide in advance (before choosing the type of cesspool) how to make a drain hole of sufficient volume. Its required capacity is calculated by the formula:

V=Nday•Hperson•Vday/person

Wherein:

  • V is the estimated volume of the cesspool, m 3;
  • Ndn - the number of days of work of the pit for accumulation (before pumping out);
  • Khchel - the number of permanent households;
  • Vday / person - daily water consumption by one household, l.

For example, for a private household with permanent residence of 5 people, cleaning the cesspool once a month and water consumption of 150 l / person, the volume of the cesspool will be: V=30•5•150=22.5 m 3 .

We increase the resulting volume by at least 10% (filling the pit to the top is prohibited by the norms) and we get the volume of the cesspool: V = 22.5 + 22.5 • 0.1 = 24.75 m 3. Let's round the value up to 25 m 3 - better more than less. The correct value of daily water consumption depends on the need of the household for bathing and washing, i.e. from their daily habits. According to statistics, city dwellers use more water than rural dwellers.

You can, of course, prepare a volumetric septic tank, calculating its cleaning once every two months. But the sewage tank truck does not accept more than 11 cubes

It is not worth digging a cesspool deeper than 3 m. Its bottom should not be in direct contact with the groundwater horizon; according to the standards, it must be at least 1 m above their level. Suppose that in the spring-autumn rainy season, the perch is at a depth of 3.5 m. This means that the depth of the drain pit can be no more than 2.5 m.

Since laying the walls of a rectangular cube is easier than that of a round tank, a rectangular cesspool will be considered. But a round septic tank is more reliable in operation, since the pressure of the soil on its walls is much lower.

The volume is calculated by multiplying the sides of the cube. We determine the long side (width) at the place of the future placement of the cesspool, taking into account the convenient entrance of the sewage truck. Let the width be 5 m. Then the length will be 25:2:5=2.5 m.

There is no need to get carried away with the capacity of the drain pit. The capacity of the sludge tank, as a rule, does not exceed 10 m 3 . This means that such special vehicles are not capable of emptying an overflowing sewer bin of a larger volume (as in the example above) and taking out waste at a time.

It is more rational to arrange a cesspool with a volume of up to 10 m 3 and empty it every two weeks. After all, a large sewer bunker will take away usable area in a suburban area, which can be used for something no less important.

Construction of a cesspool

If it is easier to install a factory-made septic tank, then it is cheaper to build a single-chamber brick cesspool. Such a sewage system is quite suitable if there is not much space on the site and the daily discharge of sewage does not exceed one cubic meter. We will figure out how to properly dig and build a drain pit with brick walls.

A drain pit with a filter bottom (fig. on the left) can only be used for gray drains or for the disposal of water that has come out of a multi-chamber septic tank. To collect brown sewer masses, sealed storage tanks are built (Fig. right)

Porous or silicate brick is not suitable, you need a clinker made of baked clay. Only walls made of clinker bricks are able to withstand mechanical loads from soil movements for years, do not collapse under the constant influence of moisture and do not let it into their own thickness at all.

The best option for a single-chamber brick storage is a fully waterproofed structure, which is periodically emptied by vacuum trucks. If a drain pit is arranged for the disposal of gray effluents coming from a kitchen sink, bath, shower, etc., then a brick structure is arranged with a permeable bottom like a filter well.

The bottom of the filtering or otherwise absorbing well is filled with a soil filter, composed of layer-by-layer sand, fine, then coarse gravel or crushed stone. The thickness of the cleaning backfill should be at least 1 m, between its conditional base and the highest groundwater level noted during the rainy season, there should be at least a meter.

In the case of installing a brick sewer structure on sandy loamy soil, the filtration properties of which are not enough for the free passage of treated effluents, its throughput is increased. This is done by forming holes in the lower part of the walls, performed during masonry.

We will analyze the construction of the simplest option - a storage pit for draining waste that does not perform absorption functions. Its bottom and walls will not let the waste mass clarified and disinfected by a soil filter into the environment.

The optimal depth of the pit for the drain pit is 2-2.5 m. There is no need to dig deeper - the hose of the sludge machine will not reach

Digging a pit. Having chosen the optimal dimensions of the cesspool, we proceed to the preparation of the pit. It is necessary to increase the distance between its walls so that a half-meter indent is maintained from the brickwork to the slope of the pit. Otherwise, applying external waterproofing to the walls of a brick septic tank will be an impossible task.

Tank base preparation. A 200 mm layer of sand and gravel cushion is poured onto the leveled bottom of the pit, and it is carefully rammed. Roofing material overlaps on top, it blocks the leakage of cement laitance into the ground during concreting.

Waterproofing the bottom of the pit before pouring concrete will reduce the loss of cement laitance. A sewer bin badly needs a moisture-proof bottom

A mesh reinforcing cage (8-10 mm reinforcement, cell 100-150 mm) is exposed to the roofing felt flooring. The frame is tied with flexible steel wire. Welding is not suitable, because. degrade the strength of reinforced concrete.

Concrete bottom casting. To achieve better waterproofing, a mortar of concrete grade M300 and higher should be used. The thickness of the concrete base of the cesspool is 150 mm. From the moment the bottom is poured with concrete, you should wait 7-10 days, only after you start laying the walls.

Reinforcing the bottom concrete of the drain pit is important. When the bunker is fully loaded, the load on its bottom and walls will increase many times

The erection of the walls of the drain pit. It is permissible to perform masonry “in half a brick”, using a conventional mortar. However, in the final stage, it will be necessary to fill the cavity between the brick walls and the slopes of the pit with a dry cement-sand mixture. As sediment moisture enters, the mixture will harden and become a protective cover for the waste bin.

Application of waterproofing. As the brick walls rise, it is necessary to make their external waterproofing with liquid bituminous materials. You can use rolled ones, but their waterproofing efficiency is weaker. Waterproofing work should not be postponed - the higher the walls, the more difficult it is to apply waterproofing to them.

Finishing the walls of the cesspool from the inside. It is enough to plaster them by introducing liquid glass (potassium, sodium) into the solution. A plaster layer containing liquid glass will significantly reduce the moisture absorption of the walls. Mandatory surface ironing of plaster with cement.

The concrete floor of the septic tank is reliable. However, it should not be brought to the ground level, as in the image - the sewer will freeze

Drain hole cover. The waste bin must be covered with a factory-made concrete slab. A manhole is required - sewage will be pumped through it.

Instead of reinforced concrete slabs, wooden shields can be used, tarred on both sides and covered with roofing material. The overlap of the sewer facility must be thermally insulated with expanded polystyrene plates, covered with a 150-500 mm layer of soil.

A single-chamber cesspool, designed for periodic cleaning with sewage equipment, is suitable for suburban households with temporary residence of no more than 4 people. And to ensure the life of a large family, a drain pit with ground filtration of wastewater is needed. Below is a description of such a complex, designed for a family of 9 people.

Local sewerage system with wastewater treatment

A cottage equipped with modern plumbing equipment - a bathtub, a toilet bowl and a bidet - will not have enough bunker-type sewage storage. The sewage treatment complex will allow minimizing calls to specialists with treatment equipment, completely closing the need for sewerage and avoiding local problems with contamination of the soil with sewage.

The principle of clarification (purification) of domestic wastewater through a system of drainage pipes is based on the natural order of filtration of fecal waste, "working" in nature. Through the riser in the house, wastewater flows into the pipeline connecting the cottage and the septic tank. A sufficient volume of a sewer well is 2.5 m 3.

When planning the landscape of a suburban area, we must not forget about the need to clean the septic tank. The car may not pass, and its hoses are not long enough

In such an accumulator, domestic wastewater is clarified with the precipitation of the contained suspensions. It will be necessary to hire a silo pump with a team to clean the sludge deposited in the septic tank twice a year. It is also possible to self-clean with the neutralization of sediments in a specially designed compost bin (see below). The clarified sewer water is sent to the drainage network, from where it goes into the ground.

The well of the drain pit is carried out at a distance of 5-20 m from the house. The main requirement for the location and positioning of the drainage network is a sufficient distance from the building so that the sewage entering the ground does not wash away the foundation or flood the cellar.

From the sewer sump, the clarified waste stream moves first to the distribution well, then from it to the system of perforated drainage pipes made of polymer or asbestos cement.

Drainage pipes are laid at a depth of at least half a meter, in fact, at the level of development of the soil and vegetation layer. If the soil developed on sandy soil, then the length of the drains is calculated taking into account 10 m per person. In soil with a sandy loamy base, the length of the perforated pipe should reach 14–17 m, with a loamy base about 20 m.

For filtration in natural conditions, in the ground, sewage, a two-chamber or three-chamber bunker is not required. A single-chamber drive will do if you line it up correctly (+)

Waste pipes from the sewer pit to the drainage system should be placed with a slope of 0.02, i.e. there should be 2 cm of slope per linear meter. It is desirable that the main part of the pipeline be laid below the freezing depth noted in the region. The areas above the specified mark are thermally insulated with a detachable cylindrical insulation made of expanded polystyrene, polyurethane foam, polyethylene or slag filling.

The laying of a channel of 100-150 mm pipes, which drains sewage water into a storage pit, is carried out at least 50 mm above the distribution well with piping, through which clarified effluents are directed to drains.

The input and output of the pipeline into the pit is carried out through tees of 100 mm in diameter. Their upper ends must be left open, placing pipes for cleaning above them, having an equal cross section with trays that supply and discharge drains. A gap of 50 mm is maintained between the open end of the tee and each cleaning pipe. Sewer pipes made of polyvinyl chloride or polyethylene are used, the diameter of which is 100-150 mm.

One distribution well in the complex of ground wastewater treatment is indispensable. You need at least two of these.

A pipe is attached to the lower end of each tee. It must be removed 400 mm below the calculated water level in the drain hopper.

All components of the drain pit, together with the ground filtration system, need to be ventilated. This function is assigned to the sewer riser inside the house, the upper end of which is displayed above the roof level, to the cesspool itself and to each drain.

The pipeline from the distribution well to drains laid in sandy soil is carried out with a slope of 3 mm, in sandy loamy 2 mm, in loamy soil 1 mm

In the trenches dug under the filter system, the pipes are laid with the perforation down. Drain joints are insulated with roofing material, tape, just polyethylene or similar material.

Wells and drains of the wastewater treatment complex

The body of the wells, in which the elements of the drainage system are located, is best made round. When making their walls made of bricks, a 400 mm inner diameter of the circle is convenient, from concrete - 700 mm diameter.

The distribution well is not built above 400 mm, otherwise it will be inconvenient to work with the wiring inside it. Brick walls from the inside must be plastered and ironed. Outside, it is permissible to waterproof them with clay or bituminous coating.

The mouths of all distribution wells must be closed with covers made of reinforced concrete, plastic or tarred boards. A heat insulator is laid on top - slab polystyrene foam with a surface filling of soil with a layer of 200-400 mm.

The cross section of the channel for laying drains cannot be chosen arbitrarily. The operation of the filtration system depends on this

According to the direction of the drains, the wells are equipped with one-, two- and three-way water intake outlets - open pipe outlets, blocked by vertical slide gate valves. Wooden gates will be needed to adjust the water supply and when repairing the well.

At the bottom of the water distribution wells, open concrete trays are formed, leading from the supply pipe to the receiving drainage pipes. The height of the trays should be equal to the diameter of the largest pipe entering the well. Their bottom is brought to the level of the lower wall of the pipes.

In polymer drainage pipes (their lower part), slots of 15 mm wide are sawn, with a height of approximately half the diameter of the pipe. Cuts with a pitch of 1000 mm will ensure a uniform flow of clarified drain water into the ground.

The bottom of the drainage trenches is given a trapezoidal shape. In them, a gravel or crushed stone cushion with a grain size of 15-25 mm is poured with a layer of 100-150 mm. In principle, the thicker the underlying layer of crushed stone (gravel) is, the better the effluent filtration will be. After giving a given slope to the surface of the backfill, drainage pipes are placed on it. Gravel or crushed stone is poured over them with a 50 mm layer, then the soil is level with the soil level.

Drains should not be interconnected. The movement of drain water in them is carried out only through distribution wells.

The distance between the septic tank and distribution wells depends on the type of soil on the site. The required number of wells from which parallel drains are drawn is two or more.

Characteristics of the sewage and filtration complex depending on the type of soil:

  • sand. Two drains 18 m long each, with 1.5 m intermediate distance between them. Filtration field area - 70 m 2;
  • sandy loam. Five drains, each 19 m long, the step between them is 2.5 m. The area of ​​the filtration field is 231 m 2;
  • light loam. Seven drains 18.5 m long, 3 m distance is maintained between them. The area of ​​the filtration field is 495 m 2 .

In order to prevent air plugs from forming in the drainage pipes and to remove the methane characteristic of the wastewater treatment process, the drainage system will require air flow. At the end of each drain, it is necessary to build a riser from a pipe with a diameter of 100 mm, raising it 400-500 mm above the ground.

Neutralization of sediments from a septic tank

With self-cleaning of the drain pit and attempts to place sewer sludge on top of the soil, the result is the same - an abundance of flies and infections among households. Waste can and must be converted into compost, completely decontaminating them from microbes.

Having chosen a place - 15 m from the house, 25-30 m from the well - you need to dig a hole half a meter deep and of the required size. Its foundation pit is waterproofed with crumpled clay of 200-300 mm layer, concreted or lined with bricks with the sides raised above the ground. The sides are obligatory - sewage collected in the compost pit should not penetrate into the soil and infect the soil.

To completely exclude moisture exchange, a cement mortar is applied to the walls of the pit, followed by ironing. It is also useful to smear over with bitumen.

The bottom of the compost pit is sprinkled with a 150 mm layer of peat or dry soil, and garbage is placed on top. Having increased the layer of sewer sludge to 250-300 mm, it is necessary to fill it with a 100-150 mm layer of peat or dry soil. After laying the compost heap 1000 mm above the ground in layers, it is required to fill it completely with earth or peat 150-200 mm thick and leave it for 8 months to mature.

If, in the process of laying a compost pit, sprinkle layers of garbage with a small amount of ash and pour a little water over it, then the compost will mature faster and in better quality.

Videos about the construction of drain pits

Independent creation of a brick drain pit on loamy soil:

Laying a drain pit made of stone, with a headband made of bricks:

A drain pit in a suburban area is not only a need to provide for life, it is a responsibility. Simple solutions to the sewer drain problem will one day become a big problem. It is necessary to evaluate the possibilities of arranging a local sewerage system as seriously as possible, choosing an expensive, but safe solution.