Choosing an internal sanitary sewage system

Sewerage of a private house

Not a single private house can do without a sewerage system or systems. There are various types of sewage systems for a private home , from the simplest in the form of cesspools, to expensive systems that combine drainage systems, storm drains, house sewerage and treatment facilities.

To begin with, we note that the entire sewer system of a country house can be divided into storm drainage and sewerage for household purposes. Separately, foundation drainage can be highlighted. Depending on the size of the house, the features of its design and other factors, all sewerage systems are installed in combination or their various combinations. The combined sewer system is called a combined sewer system. Sewers made separately are called separate.

Undoubtedly, a sanitary system is required that collects and removes waste water from the house itself. Domestic sewerage is divided into internal and external sewerage. In essence, this is one sewer system, and the division is made according to the installation site and structural elements.

Types of sewer systems

There are three main types of sewer systems:

• industrial sewerage system, which is designed to collect and treat wastewater in production;
• storm sewers serve to drain wastewater that formed as a result of precipitation;
• a household system, which can be centralized (for an entire settlement) and autonomous (for one or several private houses).

In addition, all of the above types of sewerage systems are divided into internal and external. The internal system is a complex of household plumbing devices and pipelines that are installed inside a private home. External sewerage includes pipes, pumping stations and treatment facilities, that is, what is located outside the walls of the building.

The external sewerage system, in turn, is divided into:

• a common alloy system, where economic, domestic and rainwater are discharged together;
• a separate system in which rainwater flows are discharged separately from household wastewater;
• semi-separate system - in which wastewater is discharged separately, and then all types of wastewater are combined in one treatment collector.

The types of sewer systems used in country houses or summer cottages are rarely equipped with a centralized system for the collection, storage and disposal of wastewater and waste. Therefore, autonomous types of wastewater disposal are used:

Dry toilet

• a cesspool is the cheapest type of sewage system, but is extremely inconvenient to operate and clean;
• a biological toilet is a convenient option for small cottages; it is practically not used in a large house;
• a septic tank is the most acceptable option in terms of price and maintenance costs;
• filters and sewerage installations are designed to purify wastewater using biological agents.

Also, types of sewerage differ in the method of wastewater disposal - gravity system and using pumps.

The use of drainage type sewerage is justified in areas with deep groundwater.

The principle of its operation is that the cesspool is built deep, and the bottom consists of a natural filter.

It uses alternating layers of gravel and sand. Wastewater, passing through this filter, is purified and then goes into the soil. It is not recommended to use toilet wastewater in the drainage system. This type of sewage system is best used for bathrooms, showers and baths.

Another option for drainage sewerage is designed to collect and remove excess water from the site of a private house. Pipes with holes are buried in the ground through which moisture enters. Excess water is then drained into wells, cesspools or septic tanks. In this simple way the water level in the soil is regulated. This system is also used to collect rain and melt water. Plastic pipes should be used, since metal pipes in the ground will not last long, and they are much more expensive.

Autonomous sewage systems

When constructing autonomous wastewater disposal systems in country houses, gravity sewerage is widely used. The principle of its operation is the natural movement of wastewater under the influence of gravity. Pipes must be laid with a slight slope. Such a system is inexpensive to construct, operate and maintain. Its use is convenient; there is no need to use additional energy to drain water.

Autonomous sewage system

However, in this case the storage tank cannot be placed far from home. The level of inclination of pipes directly depends on their size and diameter. The optimal slope should be approximately 1.5 to 3 centimeters per linear meter of pipe. With a lower slope, the movement of wastewater will be difficult, and congestion and traffic jams may occur. If the slope is too large, solid waste fractions in the form of oils and grease can settle on the walls of the pipeline, which will also disrupt the operation of the entire system.

Before constructing a wastewater disposal device, it is necessary to carry out a hydraulic calculation of the sewer network . This calculation is quite complex, so it is carried out by specialists. There are cumbersome formulas by which the volume of expected wastewater is determined. Accurate sewerage calculations are made only in large or centralized systems. In a country house, you need to know and carefully consider the following values:

• diameter of drain pipes;
• pipeline slope;
• the speed and degree of filling of the storage tank, which depend on the number of residents and the number of points and drainage units.

Knowing approximately these values, it is not difficult to make a hydraulic calculation of the sewerage system.

One type of autonomous sewage system is a pressure system. It uses sewerage installations, which are used in places where the level of the storage system is higher than the water consumers of a private home. For example, a toilet or bathhouse is located in the basement or ground floor. The wastewater will not flow out of there by gravity, so a device with a pump is used to pump the wastewater. The installation may have a cutting mechanism for grinding solid waste fractions.

Construction of a cesspool

A cesspool is an inexpensive and simple means of removing wastewater from your home. To do this, it is necessary to place a tank in a pre-dug pit or build it from brick or other materials. An easier way is to buy a ready-made plastic container of the required size and bury it in the ground. First, a pipeline with a certain slope must be connected to the tank.

The disadvantage of this system is the high frequency of pumping out wastewater.

If the container is made without a bottom, it will cause damage to the site and sources of drinking water. Therefore, it is best to make a septic tank, which includes a sealed container for collecting, storing and pumping wastewater. And water purification should be carried out using biological preparations. Moreover, purified water can be used for various household needs and watering the garden.

The sanitary sewage system of a bathhouse is usually constructed of a drainage type. This is the simplest, most convenient and cheapest device. The wastewater flows into the tank by gravity. To do this, holes must be made in the floors of the steam room and washing compartment into which drain pipes must be connected and placed in the ground with a slope. It is recommended to make a drainage well to collect wastewater. Several layers of sand and gravel should be placed at the bottom of the well to filter the wastewater.

Types of sewerage systems for a private house

Let us dwell in more detail on the main types of domestic external sewerage, namely:

• Cesspool;
• Septic tank;
• Filter well.

Cesspool

The easiest way to install an external sewer system is to make a cesspool. In essence, this is a simple container (hole) in the ground, covered with a lid, into which all the drainage water from the house is drained. The walls of the pit are either concreted or lined with bricks. The walls of the pit are sealed with bitumen. Just like in the first well of the septic tank, the bottom of the pit is concreted so that sewage water does not enter the soil. The pit hatch is a concrete slab with a hole for pumping out waste.

• The advantage of a cesspool is that it is cheap to install and simple to install compared to other types of sewage systems.
• There are several disadvantages. First of all, the “unkillable” smell, as well as the frequent ordering of a vacuum cleaner to clean the pit.

A cesspool is suitable for small private houses with a small number of plumbing fixtures.

Filter well

On sandy soils, which by their structure do not allow wastewater to pass through, you can install a filter well. In construction, it is similar to the construction of a drinking well from reinforced concrete rings. A meter-long filter layer of crushed stone or gravel is laid at the bottom of the well. In addition, crushed stone is poured between concrete rings and the ground.

This filtering sewer well does not need to be constantly cleaned, but it cannot cope with large volumes of wastewater. For large volumes of wastewater and “set and forget” systems include septic tanks.

Septic tanks

Septic tanks are complex sewer systems that can be purchased ready-made or made independently. On the website you can read about both types of septic tank in the articles:

• DIY septic tank;
• Types of sewage system for a country house.

Here's a short one . The design of a septic tank is two or three connected containers. In the first, the drain water settles, and it resembles a cesspool. The second container contains a biofilter. In this container, the water is purified with special “long-lasting” compounds. From the third container, purified water enters the soil through a system of drainage pipes buried in the ground, or into the soil through the bottom on which the same crushed stone is laid.

• The advantages of a septic tank are obvious. Environmentally friendly, odorless, minimal maintenance.
• Relative disadvantage, expensive price. A significant disadvantage is that a large area is required for installation and septic tanks cannot be installed in soils where the groundwater level is high.

In conclusion

The choice of the type of sewerage system for a private house is made based on an analysis of the soil, groundwater level, soil freezing, construction site and taking into account the requirements of SNiP. The volume of planned sewage water discharge is important for selection.

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Types of treatment facilities

Unlike centralized treatment systems, on suburban land plots local structures are used that allow the accumulation or processing of wastewater:

1. Cesspool. The simplest structure, imagining a pit, the walls of which are lined with stone or reinforced with concrete. Helps to accumulate waste for the purpose of its future removal using waste disposal equipment.

1. Storage capacity . A plastic or fiberglass tank connected to the sewer system of a private home. It receives unclean wastewater, which is then pumped out by special vehicles. Unlike a cesspool, this storage tank is completely sealed and does not cause harm to the environment.
2. Septic tank . A closed settling tank consisting of two or three communicating sections. In each of them, unclean water is purified from certain wastes: in the first - suspended particles, in the second - biological waste. The third section is made leaky in order to remove excess purified water.

1. Biological treatment station . A complex system where water purification is carried out using special microorganisms for which a favorable environment is created.

Cast iron internal sewage systems

For a long time, cast iron sewerage was the only possible solution, but with the advent of high-quality plastic sewerage, it noticeably lost its position. There are currently two cast iron sewage systems on the market:

Cast iron non-pressure bell-shaped ChK sewerage system.

This traditional cast iron sewer system is made from gray cast iron with flake graphite, followed by painting with bitumen mastic or bitumen varnish (Kuzbass varnish).

Advantages of CHK sewerage

• Fire safety
• Low noise
• High temperature resistance (max operating temperature 300 C)
• High strength and durability (for the entire life of the building)
• Minimum thermal linear expansion (0.01 mm/m/S)
• UV resistance
• Unified range of standard sizes: interchangeability of products from different manufacturers

Disadvantages of Cheka sewerage

• Heavy weight and, as a consequence, labor-intensive installation
• Difficult to cut (requires special pipe cutters for cast iron pipes)
• Relatively high cost
• Roughness of the internal surface, which leads to the gradual formation of deposits inside the sewage system.
• Subject to corrosion
• Low tightness of connections
• Unaesthetic appearance

conclusions

Cast iron bell-shaped ChK sewerage as a technical solution is morally outdated, but is still in certain demand. You can connect a plastic sewer to the CC sewer; for this purpose, special transition fittings with sealing collars are produced. This makes it possible to make combined systems, where the sewer riser is made of cast iron, and the horizontal wiring is made of plastic.

Cast iron socketless SML sewerage system

This is a relatively new type of cast iron sewerage, in which socketless pipes and fittings are connected using specialized clamps. The inside of SML sewerage elements are coated with epoxy resin, and the outer coating can be either epoxy resin or a primer with acrylic varnish. SML sewerage is actively replacing the Cheka sewerage system, because while maintaining all the advantages, it is devoid of some disadvantages.

Advantages of SML sewerage in comparison with ChK sewerage

• Simple and quick installation thanks to the use of clamps
• The ability to disassemble part of the sewerage system without disturbing the rest of the pipeline structure thanks to butt-to-butt installation.
• Lighter weight thanks to centrifugal casting technology
• Good tightness of connections
• Smooth inner surface prevents deposits from forming
• External and internal surfaces are protected from corrosion
• Aesthetic appearance
• It is possible to make pressure sewer pipelines if you use suitable clamps

Pipes for local sewerage

Let's consider what types of sewer pipes are used today when arranging a private home. In principle, building regulations allow the use of the following types of pipes:

• Cast iron;
• Asbestos-cement;
• Plastic;
• Ceramic;
• Reinforced concrete (this option is used mainly for the construction of main sewerage pipelines).

However, in practice, most often, plastic pipes are used. The reason for this choice is simple - pipes made of polymer materials have many advantages. The main advantages of plastic sewerage:

• Complete absence of corrosion.
• Resistance to aggressive sewage environments.
• Ability to withstand heavy loads.
• Smooth inner surface, which reduces the risk of blockages.
• Strength.

But sewer plastic pipes are produced in a wide range; different types of plastic are used for production. What types of plastic pipes for sewerage should you prefer?

PVC

PVC pipes have been used in communication systems for quite a long time. Features of this material:

• No special tools are required to make connections. The pipes are connected “in a socket” or using a special glue (using the “cold welding” method).
• PVC pipes are rigid, so to rotate the pipeline it is necessary to use fittings - bends, tees, etc.
• Pipes can be used for both open and hidden installation of pipelines. They have an attractive appearance, so even when installed externally they do not introduce significant dissonance into the interior.
• Since PVC is one of the cheapest polymers, pipes made from it have an affordable price.

Polypropylene

Polypropylene pipes are produced single- and multi-layer. The latter are represented by the following options:

• Aluminum foil is attached on top of a thick-walled polypropylene pipe using glue, which is covered with a thin layer of polymer on top.
• The connection of all layers (main pipe, foil and protective layer) is carried out using holes perforated in the pipe.
• A less laminated plastic is used as a layer between two layers of the main polymer.

Pipe connections are made using special fittings or welding.

Advice! To weld pipes, a special soldering iron is used, which has nozzles of different diameters.

Polyethylene

Pipes made from this type of polymer have the lowest operating temperature limit. Manufacturers produce polyethylene pipes using different technologies; they distinguish between products made from low-pressure polyethylene (LDPE) and high-pressure polyethylene (HDPE).

The material has a high degree of elasticity; pipes are sold in coils. To connect these pipes, special fittings and welded joints are used.

Advice! Pipes made of cross-linked polyethylene can be classified into a special category; this material is particularly durable and has high heat resistance.

For internal and external networks

Plastic pipes (even made from the same material) can have different performance characteristics. There are pipes that are intended for installation of internal and external networks. Pipes laid inside the house do not experience serious loads, so they are less durable than those used for installing external networks.

To make it easier for the consumer to navigate, the pipes are painted in different colors. Thus, pipes for laying internal networks, as a rule, are produced in a light gray color, but more durable ones, which can be laid underground, are made in orange or yellow-brown. In the same way, the types of tees for sewerage differ; the fittings are painted in the same colors as the pipes.

So, there are various types of sewage systems that can be used in a private home or country house. When choosing the optimal one, many factors should be taken into account - the seasonality of the use of the house, its equipment with plumbing, the planned amount of drainage, geological conditions on the site.

Of course, it will be necessary to take into account the cost of the sewerage system, so that the ratio of price and performance, as well as the degree of wastewater treatment, is most favorable.

Sewage work

Do-it-yourself sewerage diagram in a private house

In most cases, the system is built in such a way that wastewater moves through the pipelines independently, without the use of pumping equipment. This is partly due to the operation of pumps in aggressive and abrasive environments. Thus, gravity sewerage forms the main part of any system. Booster pumps, which sometimes cannot be avoided, have a special design that takes into account the area of ​​operation of the equipment.

The non-pressure drainage system is made with a reserve diameter taking into account extreme weather conditions and the high probability of blockages due to tree branches, fallen leaves and other debris.

Autonomous sewage systems

Autonomous sewerage is designed for buildings remote from populated areas that do not have access to a centralized sewerage system, for example, country houses and dachas.

This type includes:

1. Cesspools. The cheapest to install, but the least practical and short-lived type of autonomous sewage system.
2. Dry toilets. This is the best option for occasional use in summer cottages, but they are least suitable for residential buildings.
3. Sewerage using a septic tank. In them, wastewater is collected, settled, and the sludge is fermented. They differ in the number of compartments and the degree of filtration of wastewater. In all respects, a septic tank is the most suitable system for country houses.
4. Overflow wells. The principle of operation is similar to a cesspool, but this design consists of 2 containers rather than 1.
5. Biological treatment systems. The mechanism of action in this case is based on the decomposition of waste by aerobic biological microorganisms. If such purification is combined with aeration, then the treated wastewater becomes suitable for watering the garden. Biorefinery stations do not require sewage maintenance and are easy to operate, but their disadvantage is their high cost and dependence on electricity. Due to almost complete wastewater treatment, biological sewer systems do not harm the ecological environment of the area in which they are used.