Sewer and other elements of the urban sewage system

Most people far from plumbing know about city sewage only that the vertical pipe in the bathroom is called a riser, and the sewer is something incomprehensible that is hidden in wells. Today we will have to get acquainted with the device of the waste system - from the internal wiring to the treatment plant. So let's get started.

Intra-house system

Let's start with the part of the waste disposal system, which is located within the walls of the house.

Comb

What is a sewer comb?

This is the name of the internal wiring. It got its name from the shape that is characteristic of apartments with an adjacent bathroom and kitchen: three taps on a horizontal pipe (for a kitchen sink, a washbasin and a bath) really resemble a comb.

In the last century, until about the 80s, the traditional material for the comb was cast-iron pipes and cast-iron fittings. Flared connections were struck with a cabol (antiseptic impregnated organic fiber) and smeared with cement mortar. Less commonly, sealing molten sulfur was used to seal the compounds.

Please note: when removing such compounds with their own hands, they have to be heated with a hairdryer, a burner or a blowtorch. Work is performed only in a gas mask or respirator. The instruction is related to the fact that the fumes are exclusively corrosive: they can cause respiratory paralysis.

In homes built at the end of the last century, solid PVC combs dominate. In today's new buildings, the sewage system inside the apartments is mounted mostly from the same PVC pipes; however, it has now become a national team and is running on socket connections with rubber O-rings. Along with PVC, polypropylene is used and, more rarely, polyethylene.

Risers

Combs, located one above the other apartments, combines sewer riser. The evolution of the materials used was somewhat shorter than in the previous case: from the cast-iron risers, the builders immediately switched to prefabricated plastic.

The riser is supplied with revisions - hatches for cleaning sewer blockages.

The layout of the revisions is normalized; they must be present:

• On the first floor of the building;
• Upstairs;
• When the floors of the house over five - every three floors.

From above the risers are open; this ensures ventilation of the sewage system. It is acceptable to combine several risers with a common fan (vent) outlet.

Lezhnevka

Sewer roof plank is a horizontal pipe that unites several risers and passes into the outlet to the well. Its laying is performed with a constant slope along the entire length in the direction of movement of the effluent. Counter-slopes are unacceptable: they will become places of constant blockages.

The slope depends on the pipe diameter:

As with the riser, the roof plan of an apartment building periodically needs cleaning.

Audits or, more conveniently, oblique tees with taps oriented against the movement of drains are installed:

• Cornering (if it is not possible to clean the bend through another revision or tee);
• With the diameter of the plank bed 100-150 mm - every 15 meters;
• With a diameter of 200 mm - every 20 meters.

Release to the well

He ends with a plank. Release fits into the soil below the level of freezing. Its beginning is necessarily supplied with a tee or revision for cleaning.

The maximum release length from revision to the well axis is limited by its diameter:

As a rule, for laying in the ground is used a cast-iron pipe. Its price is noticeably higher than that of any kind of plastic; but the ring stiffness is also much higher: the ground drawdown under the weight of the car will not cause damage to it.

Yard sewer, collector

Well

The walls of the sewer well are usually reinforced concrete rings with seams and staples embedded in the mortar, which make it possible to descend into it without additional accessories. Cover - cast iron hatch; bottom - concrete tray.

As it is easy to guess, the wells along the apartment building are located exactly opposite the outlets. Between themselves, they are connected by a cast-iron pipe of large diameter (200-300 mm), laid at the bottom level or slightly higher (in the case of differential wells, compensating for the slope of the area).

Important: in deep wells, methane and other gases produced in the process of organic decay can accumulate. By themselves, they are not considered highly toxic; however, the minimum amount of oxygen in the air can cause suffocation and even loss of consciousness. When cleaning the issue or tray insurance is required.

All sewage branches from the house to the collector are supplied with manholes. The step between them and in this case depends on the diameter of the pipe.

Collector

In simple terms, a collector is a thick pipe that carries drains of the entire city or its individual areas to the sewage treatment plant.

What materials can be used for its construction?

• The oldest of the currently functioning collectors are built of bricks..

• Most of the current structures are made of reinforced concrete.. In addition to the construction of prefabricated structures made of rings, monolithic sewage sewers are often built in giant cities with their huge volumes of effluent: the formwork is filled with concrete on site.
• Finally, large plastic pipes are becoming popular lately.. The problem of low ring stiffness is solved by their shirring. In order that the corrugated surface does not create blockages, the pipe is made two-layer, with a smooth internal surface.

How are the sewer and sewage of individual microdistricts connected? With the help of the same well: it allows you to revise the collector itself and, if necessary, clean the intake pipes.

In those rare cases when the terrain does not allow the movement of sewage by gravity, a pressure sewer is constructed. During construction, productive fecal pumps and polyethylene pressure pipes are used: if the depressurization of the gravity pipe does not lead to any serious consequences, then an accident on the sewer with excessive pressure, you understand, will not decorate the city at all.

Conclusion

We will consider our acquaintance with the sewage system, albeit somewhat superficial, held. As always, the video in this article will offer the reader additional information. Successes!