Many people, using purified water, do not even know by what methods this was achieved. However, now there are a number of cleaning methods, such as: mechanical, biological, biochemical. chemical, physical and chemical, which, in turn, are divided into types. In some cases, these methods are used in combination. Which one is most effective will be discussed below.

Purifying water from various types of impurities, heavy metals and their compounds present in it is a painstaking technological process. Now there are many methods for obtaining clean liquid; methods of treating wastewater differ according to the degree of contamination and the concentration of impurities in the water.

Why clean your drains?

The main purpose of cleansing is the destruction of contaminants of various natures and their removal. This is a complex production process, the finished product of which is... Its parameters have been brought to the established standards. Moreover, the requirements for water for various purposes differ significantly and are steadily increasing.

Cleaning methods

The choice of cleaning method depends on the type of contamination. Most often, maximum filtration is achieved by combining various methods.

From the variety of existing methods, the main types can be distinguished:

Mechanical - wastewater treatment is carried out from insoluble impurities.
Chemical. At this stage, acids and alkalis are neutralized.
Biochemical. Together with chemical reagents, microorganisms are used that consume contaminants as food.
Biological. Water purification occurs without the use of chemicals.
Physico-chemical wastewater treatment includes several types, each of which will be discussed below.

Mechanical

Used for preliminary purification of wastewater from insoluble contaminants and used in combination with other types. The cleaning itself is carried out in several stages.

Cleansing

During the settling process, particles with a specific gravity greater than that of water settle to the bottom, and those with a smaller specific gravity rise to the surface. Light substances include oils, petroleum, fats, and resins. Similar impurities are present in industrial wastewater. Subsequently, they are removed from treatment facilities and sent for processing.

Important! To separate natural solid suspensions, a special version of settling tanks is used - sand traps, which are made tubular, static or dynamic.

Straining and filtration

Grids are used to separate large contaminants in the form of paper, rags, etc. To capture small particles when purifying water, fabric, porous or fine-grained filters are used. For the same purpose, micro-filters are used, consisting of a drum equipped with a mesh. The flushing of separated substances into the collection hopper occurs under the influence of water supplied through nozzles.

Biochemical

The wastewater treatment system, which uses special microorganisms together with chemicals during operation, comes in two types:

The first ones carry out water purification under natural conditions. These can be reservoirs, irrigation fields where additional soil purification is necessary. They are characterized by low efficiency, high dependence on climate conditions and require large areas.

The latter operate in an artificial environment where favorable conditions are created for microorganisms. This significantly improves the quality of cleaning. Such stations can be divided into three types: aeration tanks, bio- and aerofilters.

Aero tanks. Productive biomass is activated sludge. Using special mechanisms, it is mixed with the delivered wastewater into a single mass.
A biofilter is a device with a filter bed. Materials such as slag and expanded clay gravel are used for it.
The aerofilter is constructed on the same principle, but air is forced into the filter layer.

Biological

Biological methods of wastewater treatment are used when there are organic pollutants. A greater effect is observed when using aerobic bacteria. But oxygen is required to ensure their life. Therefore, when working in artificial conditions, air injection is necessary, which leads to increased costs.

The use of anaerobic microorganisms reduces costs, but is inferior in efficiency. To increase the quality of filtration, previously processed wastewater is further purified. Most often, contact clarifiers, which are a multilayer filter, are used for this purpose. Less often - microfilters.

Purifying wastewater using this method removes toxic impurities, but at the same time saturates it with phosphorus and nitrogen. The discharge of such water will disrupt the ecological system of the reservoir. Nitrogen removal is carried out in other ways.

Physico-chemical

This treatment method allows one to separate finely dispersed and dissolved mixtures of inorganic compounds from wastewater and destroy difficult-to-oxidize organic substances. There are several types of such purification, the choice of which depends on the volume of water and the amount of impurities it contains.

Coagulation

This type involves the introduction of chemical reagents: ammonium salts, iron, etc. Harmful impurities settle in the form of flakes, after which their removal is not difficult. During coagulation, small particles stick together into large compounds, which significantly increases the efficiency of the sedimentation process. This treatment method removes the bulk of unwanted impurities from wastewater. It is used in the construction of industrial treatment systems.

Flocculation

To speed up the process during which sediment formation occurs, flocculation is additionally used. When in contact with harmful impurities, the molecular compounds of the flocculant are combined into one system, which makes it possible to reduce the amount of coagulant. Precipitated flakes are removed mechanically.

Flocculants come in different origins: natural (silicon dioxide) and synthetic (polyacrylamide). The speed of the flocculation process is influenced by the order of addition of reagents, temperature and level of water contamination, and with what frequency and strength mixing occurs. The residence time of the wastewater in the mixer is 2 minutes, and the contact time with the reagents is up to one hour. After that, the water is clarified in settling tanks. The cost of coagulants and flocculants can be reduced by double treatment of wastewater, when the initial settling is carried out without the use of reagents.

Adsorption

Important! There are a number of substances that can absorb harmful impurities. This is the basis of the adsorption method. Activated carbon, montmorillonite, peat, and aluminosilicates are used as reagents.

Wastewater treatment using this method is highly effective and allows you to remove various types of contaminants. There are two types of adsorption: regenerative and destructive.

The first option is due to the removal of harmful impurities from the reagent and only after that their disposal occurs. In the second, they are destroyed simultaneously with the adsorbent.

Extraction

Harmful impurities are placed in a mixture consisting of two liquids that do not dissolve in one another. They are used when it is necessary to remove organic substances from wastewater.

The method is based on adding a certain volume of extractant. In this case, harmful substances leave water and concentrate in the created layer. When their content reaches the maximum value, the extract is removed.

Ion exchange method

Thanks to the exchange occurring between the contacting phases, it is possible to remove radioactive elements: lead, arsenic, mercury compounds, etc. When the content of toxic substances is high, this method is especially effective.

Chemical

All chemical methods of wastewater treatment are based on the addition of reagents that convert dissolved substances into a suspended state. After this, they are removed without any difficulty.

The following reagents are used:

oxidizing agents (ozone, chlorine);
alkalis (soda, lime);
acids.

Neutralization

Wastewater treatment in this way neutralizes pathogenic bacteria and brings the pH level to the required standard (6.5-8.5). The following methods are used for this:

mix alkalis and acids in the form of liquids;
chemical reagents are introduced;
filter wastewater containing acids;
neutralize gases using alkalis and acids - ammonia solution.

Oxidation

When impurities cannot be removed mechanically and by settling, oxidation is used. The reagents in this case are ozone, potassium dichromate, chlorine, pyrolusite, etc. Ozone is rarely used due to the high cost of the process and is explosive at high concentrations.

Recovery process

Important! The essence of the method: the physical state of all harmful contaminants is restored, and then they are removed by flotation, sedimentation or filtration.

When it is necessary to remove arsenic, mercury, and chromium, this method is used.

Flotation

Flotation method - cleaning using high pressure air

This is a method in which the floating of garbage to the surface is achieved by adding vortex air flows to the wastewater. The effectiveness of the method will depend on the hydrophobicity of the particles. The resistance of air bubbles to destruction is increased by adding reagents.

The efficiency of wastewater treatment by various methods can be presented in the form of a table for clarity.

Recycled sludge, which is the result of treatment of domestic wastewater and some industrial sectors, can be used by agriculture as fertilizers.

Alex, May 20, 2017.

Ask your question about the article

The installation of a sewerage system in the absence of a centralized system is a complex engineering task. The sewerage scheme is determined by the type of toilet equipment, the total volume of “gray” wastewater from washbasins, bathtubs, washing machines, and swimming pools. And also by the geological features of the area: the depth of groundwater, the filtering ability of soils, the presence of water intakes in the immediate vicinity of treatment facilities.

Wastewater entering the sewer network may contain waste of mineral origin (sand, clay, slag particles, salts, acids, alkalis dissolved in water); rotting organic matter (animal and plant origin); pathogenic bacteria, harmful chemicals. Wastewater treatment methods used in local sewage systems can be divided into three main types: mechanical, chemical and biological.

Chemical cleaning method wastewater treatment is based on the use of various reagents that convert dissolved impurities into a sparingly soluble state. Next, precipitation of these substances occurs. This method is mainly used for treating industrial wastewater.

Mechanical cleaning consists in removing from the waste liquid waste of mineral origin, which is in it in an undissolved and partially suspended state, as well as from foreign objects floating in the waste water. When using a mechanical cleaning method, wastewater is settled and filtered. One of the disadvantages of this method is that the water is not purified from dissolved organic contaminants. Therefore, mechanical treatment facilities (settlers, sand traps, grates and sieves) are most often a preliminary step before biological treatment.

IN biological treatment wastewater involves bacteria, which, depending on their relationship to oxygen, are divided into two groups: aerobes (using oxygen dissolved in water during their respiration) and anaerobes (developing in the absence of free oxygen).

Anaerobic (without air access) cleaning carried out in closed containers (digesters, septic tanks, two-tier settling tanks), where organic pollutants are fermented with the help of methane-forming anaerobic bacteria.

At aerobic (air supply) cleaning wastewater, drainage fields, filter wells, biological filters and aeration tanks are used, in which the purification process takes place intensively. The oxygen necessary for the life of microorganisms comes from the surrounding air or is pumped in by special compressors (blowers). A large amount of organic substances contained in wastewater serves as a favorable breeding ground for aerobe bacteria, which are able to absorb various organic substances during their life processes. During biological treatment, activated sludge is created. Sewage is mixed with activated sludge, significantly accelerating and improving oxidation processes. As a result, pathogenic microbes are absorbed by activated sludge, die or become its active agents, or they decompose into harmless ones. Thanks to this, the water loses its tendency to rot, becomes transparent, and its bacterial contamination is reduced.

Modern biological treatment plants use both types of bacteria: anaerobes and aerobes. First, the sewage flows into a container with anaerobes and is oxidized there for 2–3 days, then it undergoes a post-treatment process in containers with aerobes or under natural conditions. During biological treatment, waste liquid is almost completely freed from organic substances and harmful bacteria.

Rice. 24. Dry toilet

For a summer house, you can choose a cheaper option: arrange a treatment for draining gray water from sinks and showers and use a dry closet (Fig. 24). This is an intermediate option for those who do not want to install an expensive sewer system and at the same time want the “latrine” to be more convenient than the “outhouse” - a backlash or powder closet.

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What do you know about sewerage? Filling the gaps

If you ask the majority of the population what sewage is, it will not be difficult to answer, regardless of where they live. A resident of London, Paris, Moscow, Vologda or an urban village somewhere near Krasnoyarsk understands perfectly well what we are talking about, although he has little idea what happens to wastewater outside a residential building or production workshop.

I will fill this gap in your knowledge by describing and illustrating the operation of the entire system, I will talk about wastewater accounting, and the treatment of hazardous and domestic wastewater. So, let's go! I promise it will be interesting.

Studying wastewater

I think there is no need to explain that water from an apartment’s bathroom and wastewater from galvanic production differ significantly in a number of ways. Accordingly, disposal methods will also be different, primarily in terms of chemical and bacteriological composition. Let's find out what the possible options are.

Pedigree of drains

In most cities and towns there are various industrial enterprises that are connected to the city-wide sewerage system. The sector of the national economy that deals with toxic or aggressive substances often has its own treatment facilities. In both cases, their waste is called industrial waste;
As for household wastewater, first of all they pose a danger of biological contamination: the organic matter they contain is a breeding ground for numerous colonies of bacteria. Such wastewater is purposefully sent to treatment facilities located outside populated areas;

Captain Obviousness suggests: in the absence of a central sewerage system, sewage transport is used, or the wastewater is disposed of locally after separation of solid fractions.

We should not forget about natural runoff - rain and melt water must also go somewhere from the asphalt avenues and streets of our cities. Storm sewers function for these purposes, which are often discharged into a nearby body of water without any treatment.

Important: I will reassure all environmentalists - there are no violations here, since rainwater drains and drains only discharge water that spilled onto the ground naturally.
The degree of its pollution is not so critical and does not pose a threat to the local ecology.

Structural analysis

We have more or less dealt with domestic wastewater, let’s move on to industrial wastewater. And here the situation is much more complicated.

Drains can be:

With mineral contamination;
Contaminated with organic matter;
Combining both types of pollution.

The degree of contamination is also important, on which the cleaning method primarily depends - you must agree that different amounts of impurities, for example, 100 mg/l compared to 10,000 mg/l, require a fundamentally different approach.

In the example given, this is far from the worst option. But, you must admit, wastewater with this composition cannot be discharged into a reservoir or onto filtration fields.

How to calculate stocks

It’s logical to start thinking with private households - water comes into the system from a well or city water supply, and its consumption is easily determined by water meters. If the drainage is carried out into the city sewer system, then the owner of a private house is issued a total bill for the water consumed and services for drainage of household wastewater.

The situation with industrial enterprises is much more complicated. After all, a number of them have both their own water intakes - reservoirs, lakes and rivers, and treatment facilities. In addition, the volume of wastewater does not correlate linearly with the amount of water consumed. For example, due to the fact that water in the production cycle turns into steam, respectively, without ending up in drains.

And yet, part of the wastewater is still discharged by enterprises into city sewer networks. And since recycling is expensive, the utility bills each of them. True, sewerage metering is carried out not according to the readings of water meters, but with the help of special devices that read close to real volumes of wastewater.

Why “close to real”? Let's figure it out.

Gravity systems

A sewage meter, designed for installation in a gravity sewer, operates on the principle of measuring the actual liquid level with a previously known cross-section. By receiving wastewater parameters in real time, it is easy to determine the average flow rate per unit of time.

What kind of device is this, and on what principle does it work?

Metering device design	Technical description
Lever	The simplest measurement method: the liquid level is measured by the position of the float. The float itself is connected to the measuring part of the device by a rocker arm.
Electromagnetic	Wastewater with a high salt content is an electrolyte that interacts with the electromagnetic field of the measuring instrument. The actual flow of wastewater can be judged by its changes.
Ultrasonic	The speed of propagation of sound vibrations in air and water (empty or filled pipe) depends on the level of the liquid. The device measures the sound delay in real time and records the current liquid level.

I note that such readings cannot be considered ideally accurate, since the measurement result is reliable only for perfectly clean sewer pipes.
As you understand, such a situation is impossible in principle - solid fractions in wastewater, siltation, etc. will introduce distortions into the values recorded by instruments.

Pressure systems

We have looked at the principle of metering wastewater in gravity systems, and now let's find out how a meter functions on a pressure sewer. Logic dictates that the principle is the same as that of any measuring device for a water supply system.

But, unlike its “colleague in the shop”, which supplies clean water, the pump for pumping sewage is used for other purposes:

Creates excess pressure in the sewer pipe;
Grinds partially large fractions of wastewater.

To calculate the volume of waste, you need to know the cross-section of the pipe and the flow speed. And the well-known Bernoulli law helps solve the problem. Let me remind you of it for those who have forgotten the school formulas - static pressure in a fluid flow is inversely proportional to its speed.

The practical implementation of Bernoulli's law for accounting is quite simple:

wastewater is passed through a pipe of variable diameter;
measure the pressure in its sections with different sections;
calculate the flow rate.

Treatment plants

Let's return to our story and look at how wastewater is purified, the amount of which is accurately measured directly at the utility companies responsible for its processing.

Urban systems

Domestic wastewater entering the city sewer system:

Passed through primary coarse filters. These are gratings that trap large debris, sieves of various diameters and sand traps. Accumulated solid waste (solid waste) is subsequently transported to landfills;

Sand from sand traps is used by the enterprise when carrying out restoration work of the sewer network.

Pass through grease traps that collect fat from the surface of wastewater;
End up in settling pools. The wastewater remains in them for several days, and during this time heavy particles precipitate, where they are subsequently removed by scrapers. Surface contaminants are driven into a storage hopper by a special float;

After settling tanks, wastewater is subjected to biological treatment– the water is forcibly aerated, oxygen-consuming bacteria are activated, eating all organic matter;
At the next stage, physical and chemical processing occurs– wastewater is passed through a molecular membrane that removes solutions of potentially hazardous substances;
At the last stage, disinfection is carried out using ultraviolet light and chlorine treatment.. The purpose of their impact on wastewater is to destroy colonies of pathogenic bacteria that can cause epidemics, both among people and among domestic and wild animals.

Industrial wastewater

Unlike domestic wastewater, industrial wastewater treatment involves a number of additional operations:

To neutralize aggressive substances (for example, acids), appropriate reagents are used. Most often, caustic soda is used as a neutralizing additive;
For waste containing hydrocarbons, there is also thermal disposal. It involves the initial spraying and combustion of a water-air mixture in furnaces and burners. Under the influence of high temperatures, water evaporates, and the dangerous components of wastewater decompose into substances harmless to nature - carbon dioxide and water;

Removal of toxic suspensions by centrifugation: wastewater is fed into a drum rotating at high speed, where it settles on its walls, and is subsequently removed and disposed of in special landfills.

Sewerage of private households

All this is interesting, some readers will say, but we have our own house, and we are not connected to the city sewer system. It is for this category of readers that I will tell you how to clean sewer drains in a private house. After all, for the majority it is quite primitive, and not everyone knows how to properly modernize it.

The most effective solution today is a biological sewage treatment plant, which uses aerobic decomposition in its work. With its help, you can achieve a fantastic degree of wastewater purification of 95-98%.

The compact device operates according to the already familiar principle of operation:

Large particles and light fractions are retained in the first and second chambers of settling tanks;
The wastewater is then transferred to an aeration tank equipped with a compressor. The air pumped by it promotes the rapid proliferation of colonies of aerobic bacteria, which actively eat organic matter;
The purified water is discharged into the soil or used for watering flowers.

Captain Obvious tells us: all good things come at a price.
And the price of deep cleaning stations is quite high, which does not contribute to their mass distribution.
That is why septic tanks with the described principle of operation are often built with their own hands.

The proposed design is quite simple:

In the first settling tank, wastewater remains for several days, being separated into heavy and light fractions, as well as water;
The separation of wastewater into fractions continues in the second settling tank;
The water taken from the middle of the second tank enters the third for soil purification. Its design involves the natural absorption of wastewater by the soil.

Plumbing is an integral part of modern comfort, and where there is a water supply, there must also be drainage. But what to do with accumulated wastewater? Now there are many options for solving this problem, ranging from primitive recycling to complete purification of the contaminated fraction from process water. This article discusses the most common methods of wastewater treatment, the principle of their operation, and the main pros and cons of such systems.

Wastewater treatment methods

First you need to understand what wastewater is? This category includes any wastewater that contains any impurities or contaminants. These include:

Domestic sewerage in the residential sector. It contains mainly waste products, biological waste of animal origin, such as fat and food particles. Wastewater treatment technology can be produced locally or globally;
Industrial wastewater contains industrial waste, chemical elements, polymers or petroleum products. Recycling such contaminants differs from cleaning domestic sewage; this process is more complex and includes a set of measures with several levels. Such installations are capable of not only processing wastewater, but also providing the enterprise with water for production needs.

Thus, based on the type of sewage, it is possible to determine the type of treatment facility that will be most suitable for achieving the desired result and level of treatment.

Methods of wastewater treatment can be classified into three types:

Mechanical methods of wastewater treatment. As a rule, this stage is considered preparatory, since this is the most primitive method in which there is no other than physical impact on contamination from large fragments. Mechanical wastewater treatment is carried out in several ways:

Straining. At this stage, the effluent is passed through a steel or plastic screen that retains large elements and fibers. Most often, such a mechanism is equipped with an electric drive; it rotates the mesh as water is supplied, and at the top point all contaminants are removed for disposal;
Advocacy. The settling mechanism is based on the physical property of the material to settle at the bottom of the container. Since water is lighter than the main types of contaminants, all elements sink down and accumulate in the water column. After sedimentation, contaminants are removed from the sump by emptying it or draining it through the bottom of the channel;
Filtration is carried out using a fine mesh catch mesh. This method is justified in cases where there are no large contaminants in the wastewater or as an intermediate stage of purification;
Separation or centrifugation. One of the most modern types of water separation from dirty wastewater. The operating principle of this device is based on the movement of water in a spiral in a special drum; during this rotation, large and suspended particles are separated from the process water.

This method is one of the main methods of wastewater treatment.

Chemical methods of wastewater treatment. This method is designed to separate substances dissolved in wastewater from the main mass by adding special reagents, which, when released into a contaminated environment, react with the liquid and contribute to the precipitation of harmful substances. Chemical wastewater treatment, depending on the additives used, is divided into two subsections:

Neutralization with acids and alkalis. At this stage, chemicals are added to the wastewater, which bring the liquid to the required value and weight of hydrogen. This method is most often used in textile and other industries;
Oxidation using chemical reagents, which can be liquefied chlorine and its other derivatives. The main direction in the processing of such a plant is the treatment of wastewater with a high content of heavy metals.

Physico-chemical methods of wastewater treatment. This is one of the most advanced methods of recycling contaminated liquids, which includes several stages of separating and removing finely dispersed and poorly soluble organic and non-organic elements. Just like previous methods of wastewater treatment, this process comes in several types:

Coagulation is an action based on the coarsening by sticking together of small particles during reaction with added reagents. The most commonly used salts are ammonium, copper and iron. In domestic conditions it is rarely used due to the high cost and large dimensions of the equipment;
Flotation. In this case, a special installation is required, into which sewage flows and natural or chemically created flotation agents, such as oil or petroleum by-products, are added. To ensure a continuous cleaning process, compressed air is supplied to a separate chamber under high pressure, which, passing through the drains, forms a foam emulsion. Flotation forms oxygen bubbles that capture molecules from the general composition and lift it to the upper layers. As a result, aggregation of elements occurs in dense foam. This method is used in metal mining to separate useful ore from other minerals. Flotation is also used in modern urban wastewater treatment plants;
Sorption treatment of domestic wastewater. The most advanced cleaning method, it uses large sorbents of natural or chemical origin. Contaminated wastewater is mixed with porous material, and after settling into sediment, the filter is removed from the container, and the technical liquid can be reused. The level of purification with this method reaches 95%. The main disadvantage of sorption is the high cost of components and equipment;
Simple and reverse osmus. In such a device, the treatment of domestic wastewater occurs as a result of squeezing water through contaminated drains and a membrane, or the reverse process with the passage of dirty water through a filter element and separation of waste molecules. The principle of operation in both directions is the same; it is based on the mechanical retention of particles that are larger than water molecules in a special mesh. Once the filter is full, it must be removed and replaced or cleaned.

All physical and chemical methods of wastewater treatment are mainly used on an industrial scale for large enterprises and factories. The industrial and household methods differ in the equipment used and the number of processes. But some units are also used in private sectors, for example, flotation or osmus.

Biological method of sewerage wastewater treatment. Most often, this method is used when constructing treatment facilities for individual homes with an autonomous communications system. Its operating principle is based on the processing of contaminants by creating a breeding ground for special bacteria intended for wastewater treatment. There are two types of microorganisms suitable for wastewater treatment:

Anaerobic bacteria - live in the polluted, airless environment of sewers and feed on biological waste. Anaerobic wastewater treatment has a by-product in the form of methane gas, so the tank must be equipped with a gas vent. Colonies of bacteria are also called beneficial sludge, since they live on sand particles contained in an aquatic environment;
Aerobic bacteria, unlike the previous ones, require a constant supply of air, since they need oxygen for normal life. The waste container must be equipped with a compressor unit and a pipe supply for enrichment of wastewater.

Often both options are used sequentially to achieve the desired result, then the level of sewage treatment can reach 98%. This water cannot be consumed as food, but it is suitable for domestic needs, for example, for watering plants or cleaning. Often the aerobic scheme is used in conjunction with another oxygen method called flotation.

Note! Regardless of the chosen method of treating household wastewater, its design and installation must be carried out by qualified workers, since it is possible to independently calculate the required power only after a detailed study of all communication parameters.

Stages of wastewater treatment, stages and construction of an autonomous septic tank

The treatment of domestic wastewater in the enterprise and in the private sector is very different from each other. In individual housing, a combined treatment system is often used, which includes several stages of processing the liquid to the state of industrial water. The construction of such a structure begins with calculating the power and determining the location. As a rule, the septic tank is located at some distance from the residential building, closer to the exit from the site. This is done to ensure that during operation there are no problems with the removal of used material and waste.

The next step will be digging a pit for the containers. Many manufacturers make rigid plastic tanks with built-in partitions and compartments for overflow, filtration and recycling. Such a product is much more expensive than reinforced concrete rings, since its production is expensive, but it has the advantage of ease of installation and maintenance, as well as saving space. The guarantee on plastic containers is more than fifty years.

It is important to observe the dimensions of the pit so that it is 20-30 cm larger around the perimeter, this will facilitate installation and prevent destruction of the walls of the pit.

Geotextiles are laid on the sand and gravel bed, which will prevent the container from sagging under the influence of heavy weight. After compacting the base, the septic tank itself is installed; it can be factory-made or made independently from reinforced concrete rings. If a plastic tank is used, then it is necessary to place a weight on the bottom so that when precipitation falls, the container does not float out.

The sewer pipe is routed along the top cover so that there is an air gap between the accumulated wastewater and the incoming liquid. To prevent unpleasant odor from the septic tank from entering the room, it is recommended to install a check valve that operates only in one direction, regulating the flow.

Most often, the first stage of sewer water purification is natural filtration from large fragments of non-biological origin. For this purpose, the container is equipped with an overflow threshold with a sand trap, which sifts out elements unsuitable for processing from the main mass.

In the next compartment there are anaerobic bacteria that purify the liquid from large inclusions contained in the thickness of the drain. Having processed the main pollutants and converted them into carbon dioxide and methane, the bacteria partially die; in order to maintain the required numbers, their population must be periodically updated.

After overflow, the recycled water enters the aeration fields. Bacteria live here, feeding on biological waste when enriched with oxygen. Therefore, to ensure the process, oxygen must be continuously supplied to the chamber; without it, all microorganisms will die.

Sewerage: cleaning, removing blockages. Treatment facilities, biological wastewater treatment