In individual construction, we strive to create the best conditions for living and recreation. To do this, during the construction process, it is necessary to meet a number of sanitary and hygienic requirements, in particular, to ensure the possibility of removing waste water (from sinks, toilets, washbasins, bathtubs, showers, etc.). Simply put, a household sewage system must be installed in the house and on the site.

Sanitary fixtures and wastewater receivers

For receiving waste water in premises, sewer pipes with a nominal bore of 25 mm or more are used. Pipes and fittings used in the construction of an internal sewerage system must meet sanitary standards, technical conditions and state standards.

Wash basins of various shapes and designs are used to wash hands and faces. Cast iron or steel bathtubs 1.5 or 1.75 m long are installed in bathrooms. Sitz bathtubs are convenient to use, especially if there are elderly people in the house. Developers with a solid income can buy expensive bathtubs such as “Yukon”, “Jacuzzi”, etc. Toilets are equipped with individual flush tanks and seats with a lid. For convenience, a wall-mounted urinal can be installed in the toilet room, and a bidet for personal hygiene.

Pipes

For the sewerage system, light steel galvanized pipes (with a nominal bore of 25–65 mm) and cast iron (50–100 mm) with shaped parts are used. For non-pressure pipelines, asbestos-cement pipes with a diameter of up to 100 mm, plastic and vinyl plastic pipes with a nominal bore of 10 mm and higher, as well as polyvinyl chloride and ceramic (in most cases in industrial sewerage systems) are used.

 

Laying of sewer pipes

Wastewater drainage is provided through closed gravity pipelines. Network sections are laid in a straight line. Changing the direction of pipeline laying and connecting devices is done using shaped parts. In this case, it is prohibited to allow changes in the slope of the laying on the section of the branch (horizontal) pipeline. To connect the branches to the riser in the basement, oblique crosses and tees are used (see Fig. 1). Bast fibers treated with wood resin – tow – are used to seal pipe joints.

Fig. 1. Cast iron 45 ° oblique tee

Method of laying networks

According to the method of installation, the sewerage network can be:

open – in the underground, basement or in an auxiliary room with fastening to the building structures (wall, ceiling) or on supports;

hidden – pipes are sealed in the ceiling, laid under the floor (in the ground or channels) or in attached boxes near the walls, in false ceilings, under baseboards in the floor, etc.

It is prohibited to allow internal sewer networks to be laid under the ceiling, in the walls and floors of living rooms, in the electrical panel of the house, under the kitchen ceiling (openly or hidden). If you are building a 2-3-story house, and the domestic sewer risers are located on the upper floors and pass through the kitchen, then you should provide a plastered or tiled box. It is not necessary to install a revision in the box.

 

Network ventilation

The household sewerage system that discharges wastewater into the external sewerage system must be ventilated through risers, the exhaust part of which is led through the roof to a height of 0.5 m. The exhaust part of the riser led above the roof must be located at a distance of at least 4 m (horizontally) from openable windows and balconies. The exhaust part of the sewer riser must not be connected to the chimney. The diameter of the exhaust riser must be equal to the diameter of the waste part of the riser (see Fig. 2).

Fig. 2. Exhaust pipe on the riser

1 – sewer drain

Installing revisions

To clean domestic sewage, so-called revisions are installed. If there are no indents on the riser, revisions are located on the lower and upper floors of the house, but if there are indents, revisions are installed above them. The distance between revisions (or cleanings) with a pipe diameter of 50 mm is taken from 8 to 12 meters. Revisions are installed in a place accessible for maintenance.

Unventilated sewer risers

In low-rise buildings, the sewer riser can be installed without an exhaust hood. In this case, the riser must end with a cleaning, which is installed in the socket of the straight branch of the cross or tee at the level of the connection of the highest located devices to this riser.

Slope of pipelines

The maximum slope of the pipeline should not exceed 0.15. The exception is branches from plumbing fixtures up to 1.5 meters long.

 

Sewer outlets

The diameter of the sewer network outlet must be no less than the diameter of the largest of the risers connected to the outlet. The outlet is connected to the external network at an angle of no less than 90 degrees relative to the direction of movement of wastewater (see Fig. 3).

Fig. 3. Exit from the building

1 – inspection; 2 – to the septic tank

Intersection of the outlet with the wall

At the intersection of the sewer outlet with the basement wall in dry soils, a gap of at least 20 mm must be left between the pipe and the building structure. The hole in the wall is sealed with a waterproof elastic material. In wet soils, special seals are used.

Local sewerage

Wastewater from a private house can be discharged into a local sewer system; in this case, fecal water is purified as it passes through the soil. Wastewater from a sewer riser located in the house flows into a pipeline laid in the yard of the plot, and then into a well or septic tank.

Septic tank

The volume of a septic tank for a family of 8-10 people is enough to be 2.5-3 cubic meters. Sediments from the septic tank must be removed twice a year. In the septic tank, the sediment is clarified and goes into the soil through the drainage network. The septic tank is located at a distance of 5 to 20 m from the house (see Fig. 4).

Fig. 4. Local sewerage system diagram

1 – septic tank; 2 – cleaning; 3 – distribution well; 4 – drainage pipes; 5 – 5 cm gap

Drainage network

The drainage network is located at such a distance from the house that wastewater cannot wash away the soil under the foundation and flood the basement of the house or cellar. Drainage is arranged below the places of drinking water intake in the direction of groundwater flow. On loams, the septic tank should be no closer than 20 m from the water intake, the drainage network – no closer than 30 m, and when installing a septic tank in sandy and sandy loam soils – no closer than 50 m.

Pipe laying

The sewage discharge pipe is laid below the freezing depth of the soil. To prevent freezing of water in the pipe and rupture of the pipes, the latter are insulated with slag.

Septic tank design

Septic tanks are made of brick, rubble stone, concrete or reinforced concrete. The inner surfaces of a stone or brick septic tank are plastered with cement mortar and then ironed. The bottom of the septic tank is covered with concrete. From the outside, the septic tank is well insulated by laying a layer of fatty clay under the bottom and along the walls – at least 20 cm for concrete and reinforced concrete, and at least 30 cm for stone and brick walls.

The septic tank cover is made of reinforced concrete slabs or wooden tarred boards, covered with roofing felt or roofing felt on top. A 20–50 cm layer of soil is poured over the insulating lining, depending on the temperature conditions of the area. The thickness of the septic tank walls should be at least 25 cm. The best shape for a septic tank is round.

Trays and tees

The tray from the house drain must be higher than the tray of the pipe through which water flows from the septic tank to the distribution well, at least by 5 cm. The drains enter the septic tank and exit it through tees with a diameter of 100 mm, which are installed on the supply and discharge pipes. The upper ends of the tees are left open, and cleanings are installed above them.

The diameter of the pipe with cleaning should be equal to the diameter of the tee, and the gap between them should be at least 5 cm. The length of the lower ends of the tees with the pipes attached to them is selected so that they are 40 cm below the calculated water level in the septic tank.

Ventilation of septic tanks

Underground filtration septic tanks are ventilated through the house’s internal sewer riser, which is discharged 1–2 m above the roof.

Pipe material

Sewer pipes from the house to the septic tank and from the septic tank to the nearest distribution well are made of cast iron, asbestos-cement (?100 mm) or ceramic (?125–150 mm) pipes. The slope is at least 5 mm per linear meter of pipe.

Distribution wells

The diameter of a round brick well (in the clear) is taken to be at least 40-45 cm. The height of the well from the top of the pipe is 40 cm. The wells are insulated from the outside with fat clay, and from the inside they are plastered and then ironed. From above, the well is covered with a reinforced concrete or wooden tarred lid, on which roofing felt or roofing felt is laid and covered with earth in a layer of 20-40 cm.

Bends

Depending on the direction of the drains, wells are arranged with a one-way, two-way or three-way outlet (see Fig. 5). To turn off the drainage pipes, regulate the water supply or make repairs, valves are installed in the well.

Fig. 5. Schematic arrangement of drainage pipes in distribution wells

1 – drainage pipes ? 100 mm; 2 – wooden damper

Laying drainage

Inside the well, the pipes pass into open concrete trays with a height equal to the diameter of the largest pipe. Their bottom should be at the level of the pipe tray. In sandy soils, the slope of the drainage network from the distribution well is 1–3 mm per linear meter, and in sandy loams and loams, the pipes are laid horizontally. The length of the drainage branches should not exceed 20 m. Ceramic or asbestos-cement pipes are used, having pre-drilled holes in them. The diameter of the pipes is from 75 to 150 mm, depending on the amount of drains.

Laying pipes in the ground

When installing drainage from ceramic pipes, gaps of up to 10–15 mm are left between them, and the joints are covered from above with non-wetting and stainless sheet material or concrete overlays are made. In asbestos-cement pipes, in their lower halves, to a depth of about half their diameters, 10–15 mm wide cuts are made every meter (or holes are drilled, as indicated above). The holes in the pipes are necessary for uniform removal of runoff into the soil.

Trench

The trench is made in a trapezoid shape. The bottom of the trench is filled with crushed stone or gravel of 15-20 mm in size to a thickness of up to 10 cm, this layer is given the necessary slope, pipes are laid on it and gravel or crushed stone is poured on the sides and on top in a layer of at least 5 cm thick, and on top of this – previously excavated soil. The thicker the layer of gravel or crushed stone, the better the sewage will be cleaned.

Drains

Depending on the soil in which the septic tank is located, two or more distribution wells are installed at a certain distance from it, from which parallel branches (drains) go. In sandy soils, two drains are installed, 18 m long, with a distance of 1.5 m between them. The filtration field area is about 70 square meters (see Fig. 6).

Fig. 6. Filtration area in sandy soils

1 – septic tank; 2 – distribution well; 3 – drains (2 pcs.); S p. f. = 70 ^m2

In sandy loams, five drains are installed, each 19 m long, with a distance of 2.5 m between them. In this case, the area of ​​the filtration field is 230 sq. m (see Fig. 7).

Fig. 7. Filtration area in sandy loams

1 – septic tank; 2 – distribution well; 3 – drains (5 pcs.); S p. f. = 70 ^m2

In light loams there are seven drains 18.5 m long with a distance of 3 m between them. The area of ​​the filtration field is 495 sq. m (see Fig. 8). For air inflow, risers made of asbestos-cement pipes Ø100 mm are installed at the ends of the drains.

Fig. 8. Filtration area in light loams

1 – septic tank; 2 – distribution well; 3 – drains (9 pcs.); S p. f. = 70 ^m2

Local systems using automation

In this case, wastewater also flows by gravity into the septic tank, where it undergoes preliminary settling and anaerobic stabilization of the sediments formed (see Fig. 9). After passing through the first chamber, the partially settled wastewater flows by gravity into the complete biological treatment unit, where an aeration chamber is installed, combining the loading material, aerator and airlift. The use of such a unit allows the implementation of the method of biological treatment of wastewater under aerobic conditions.

Fig. 9. Local external sewerage system 

The basis of the method

The biological treatment method used in the local sewerage system is based on the use of microorganisms that consume organic contaminants found in wastewater for their nutrition.

Advantages of the method

The main value of the method is that there is no need to add any reagents or consumables. At the same time, the efficiency of water purification from organic contaminants is 95%, and from suspended substances – 92%. To ensure the vital activity of microorganisms, a constant supply of oxygen is required. For this purpose, a special compressor is used, which is installed in the building. The compressor power is small – only about 50 W. Water that has undergone complete biological purification in gravity mode enters the post-treatment filter, and then is automatically pumped out (using a pump) into a drainage well.

 

System indicators

The system’s capacity is 3.5 cubic meters per day and provides comfortable accommodation for up to 12 people. Purified water should contain no more than 3 mg of suspended particles per liter.

By choosing and installing one of the above-mentioned methods of sewerage and wastewater treatment on your summer cottage, you can achieve living conditions that are quite comparable to those in the city.