How sewage treatment plants work in large cities. Types and principle of operation of urban treatment facilities

Today, once again, we will talk about a topic close to each of us, without exception.

Most people don't think about what happens to what they flush when they press the toilet button. Leaked and flowed away, that's business. In such big city how Moscow sees no less than four million cubic meters of sewage flowing into the sewer system every day. This is about the same as the amount of water flowing in the Moskva River in a day in front of the Kremlin. All this huge volume of waste water needs to be cleaned and this task is very difficult.

There are two largest wastewater treatment plants in Moscow, approximately the same size. Each of them cleans up half of what Moscow "produces". I have already spoken in detail about the Kuryanovsky station. Today I will talk about the Lyubertsy station - we will again go over the main stages of water purification, but we will also touch on one very important topic- how at cleaning stations they fight against unpleasant odors with the help of low-temperature plasma and waste from the perfume industry, and why this problem has become more relevant than ever.

To start, a little history. For the first time, sewerage "came" to the area of modern Lyubertsy at the beginning of the 20th century. Then the Lyubertsy irrigation fields were created, on which sewage, according to the old technology, seeped through the ground and was thereby purified. Over time, this technology became unacceptable for the ever-increasing amount of wastewater, and in 1963 a new treatment plant, the Lyuberetskaya, was built. A little later, another station was built - Novoluberetskaya, which actually borders on the first one and uses part of its infrastructure. In fact, now it is one large cleaning station, but consisting of two parts - the old and the new.

Let's look at the map - on the left, in the west - the old part of the station, on the right, in the east - the new one:

The area of the station is huge, in a straight line from corner to corner about two kilometers.

As it is not difficult to guess, there is a smell coming from the station. Previously, few people worried about it, but now this problem has become relevant for two main reasons:

1) When the station was built, in the 60s, almost no one lived around it. There was a small village nearby, where the station workers themselves lived. Then this area was far, far from Moscow. Right now there is a lot of building going on. The station is actually surrounded by new buildings from all sides and there will be even more of them. New houses are being built even on the former sludge sites of the station (fields where the sludge left over from wastewater treatment was brought). As a result, residents of nearby houses are forced to periodically sniff "sewer" smells, and of course they constantly complain.

2) Sewer water has become more concentrated than before, in Soviet times. This happened due to the fact that the volume of water used for Lately decreased greatly, while they did not go to the toilet less, but on the contrary, the population grew. There are quite a few reasons why the "diluting" water has become much less:
a) the use of meters - water has become more economical to use;
b) the use of more modern plumbing - it is less and less common to see a running faucet or toilet bowl;
c) use more economical household appliances- washing machines, dishwashers and so on.;
d) the closure of a huge number industrial enterprises who consumed a lot of water - AZLK, ZIL, Hammer and Sickle (partially), etc.
As a result, if the station during construction was calculated for a volume of 800 liters of water per person per day, now this figure is actually no more than 200. An increase in concentration and a decrease in flow led to a number of side effects - in sewer pipes designed for a higher flow, sediment began to be deposited, leading to unpleasant odors. The station itself began to smell more.

To combat the smell, Mosvodokanal, which is in charge of treatment facilities carries out a phased reconstruction of buildings, using several different ways getting rid of odors, which will be discussed below.

Let's go in order, or rather, the flow of water. Waste water from Moscow enters the station through the Luberetsky sewer canal, which is a huge underground collector filled with sewage. The channel is gravity-flowing and runs at a very shallow depth for almost its entire length, and sometimes even above the ground. Its scale can be estimated from the roof of the administrative building of the treatment plant:

The width of the channel is about 15 meters (divided into three parts), the height is 3 meters.

At the station, the channel enters the so-called receiving chamber, from where it is divided into two streams - part goes to the old part of the station, part to the new one. The receiver looks like this:

The channel itself comes from the right-behind, and the stream divided into two parts leaves through the green channels in the background, each of which can be blocked by the so-called gate valve - a special shutter (dark structures in the photo). Here you can see the first innovation to combat odors. The receiving chamber is completely covered with metal sheets. Previously, it looked like a "pool" filled with fecal water, but now they are not visible, naturally, a solid metal coating almost completely covers the smell.

For technological purposes, only a very small hatch was left, lifting which you can enjoy the whole bouquet of smells.

These huge gates allow you to block the channels coming from the receiving chamber if necessary.

From the receiving chamber there are two channels. They, too, were open quite recently, but now they are completely covered with a metal ceiling.

Under the ceiling, gases released from wastewater accumulate. This is mainly methane and hydrogen sulfide - both gases are explosive at high concentrations, so the space under the ceiling must be ventilated, but the next problem arises - if you just put a fan, then the whole point of the ceiling will simply disappear - the smell will get out. Therefore, to solve the problem, ICD "Horizon" has developed and manufactured a special unit for air purification. The installation is located in a separate booth and a ventilation pipe from the channel goes to it.

This installation is experimental, for testing the technology. In the near future, such installations will be massively installed at treatment facilities and sewerage pumping stations, of which there are more than 150 units in Moscow and from which unpleasant odors also come. On the right in the photo - one of the developers and testers of the installation - Alexander Pozinovskiy.

The principle of operation of the installation is as follows:
polluted air is fed into four vertical stainless steel pipes from below. In the same pipes there are electrodes, to which a high voltage (tens of thousands of volts) is applied several hundred times per second, resulting in discharges and low-temperature plasma. When interacting with it, most smelling gases turn into a liquid state and settle on the walls of the pipes. On the walls of the pipes constantly flows thin layer water with which these substances are mixed. Water circulates in a circle, the water tank is the blue container on the right, below in the photo. The purified air exits from the top of the stainless pipes and is simply released into the atmosphere.

For patriots - the installation is completely designed and created in Russia, with the exception of the power stabilizer (below in the closet in the photo). High voltage part of the installation:

Since the installation is experimental, it has additional measuring equipment - a gas analyzer and an oscilloscope.

The oscilloscope shows the voltage across the capacitors. During each discharge, the capacitors are discharged and the process of their charge is clearly visible on the oscillogram.

Two tubes go to the gas analyzer - one takes air before installation, the other after. In addition, there is a tap that allows you to select the tube that is connected to the gas analyzer sensor. Alexander first shows us the "dirty" air. The content of hydrogen sulfide is 10.3 mg/m3. After switching the tap - the content drops to almost zero: 0.0-0.1.

Further, the supply channel rests against a special distribution chamber (also covered with metal), where the flow is divided into 12 parts and goes further to the so-called grate building, which is visible in the background. There, wastewater passes the very first stage of treatment - the removal of large debris. As it is not difficult to guess from the name - for this it is passed through special gratings with a cell size of about 5-6 mm.

Each of the channels is also blocked by a separate gate. Generally speaking, at the station great amount- sticking out here and there

After cleaning from large debris, the water enters the sand traps, which, again, it is not difficult to guess from the name, are designed to remove small solid particles. The principle of operation of sand traps is quite simple - in fact, it is a long rectangular tank in which water moves at a certain speed, as a result, the sand simply has time to settle. Also, air is supplied there, which contributes to the process. From below, the sand is removed using special mechanisms.

As is often the case in technology, the idea is simple, but the execution is complex. So here - visually, this is the most "fancy" design on the way of water purification.

Sand traps were chosen by seagulls. In general, there were a lot of seagulls at the Lyubertsy station, but it was on the sand traps that they were the most.

I enlarged the photo already at home and laughed at their appearance - funny birds. They are called lake gulls. No, they don’t have a dark head because they constantly dip it where they don’t need it, it’s just such a design feature
Soon, however, they will have a hard time - many open water surfaces at the station will be covered.

Let's get back to technology. In the photo - the bottom of the sand trap (not working at the moment). It is there that the sand settles and from there it is removed.

After sand traps, water again enters the common channel.

Here you can see what all the channels at the station looked like before they were covered. This channel is shutting down right now.

The frame is made of stainless steel, like most metal structures in the sewers. The matter is that in the sewerage very aggressive environment - water full of any substances, 100% humidity, gases promoting corrosion. Ordinary iron very quickly turns into dust in such conditions.

Work is being carried out directly above the existing channel - since this is one of the two main channels, it cannot be turned off (Muscovites will not wait :)).

In the photo there is a small level difference, about 50 centimeters. The bottom in this place is made of a special shape to dampen the horizontal speed of the water. As a result - very active seething.

After sand traps, water enters the primary sedimentation tanks. In the photo - in the foreground is a chamber into which water enters, from which it enters the central part of the sump in the background.

The classic sump looks like this:

And without water - like this:

Dirty water enters from the hole in the center of the sump and enters the general volume. In the sump itself, the suspension contained in the dirty water gradually settles to the bottom, along which the sludge rake is constantly moving, fixed on a truss rotating in a circle. The scraper rakes the sediment into a special annular tray, and from it, in turn, it falls into a round pit, from where it is pumped out through a pipe by special pumps. Excess water flows into the channel laid around the sump and from there into the pipe.

Primary clarifiers are another source of unpleasant odors in the plant, as they contain actually dirty (purified only from solid impurities) sewer water. In order to get rid of the smell, Moskvodokanal decided to cover the sedimentation tanks, but then a big problem arose. The sump diameter is 54 meters (!). Photo with a person for scale:

At the same time, if you make a roof, then, firstly, it must withstand the snow load in winter, and secondly, it must have only one support in the center - it is impossible to make supports above the sump itself, because. there is a farm going on all the time. As a result, an elegant decision was made - to make the floor floating.

The ceiling is assembled from floating stainless steel blocks. Moreover, the outer ring of blocks is fixed motionless, and the inner part rotates afloat, together with the truss.

This decision turned out to be very successful, because. firstly, there is no problem with the snow load, and secondly, there is no air volume that would have to be ventilated and additionally cleaned.

According to Mosvodokanal, this design reduced odorous gas emissions by 97%.

This sump was the first and experimental one, where this technology. The experiment was recognized as successful, and now other sedimentation tanks are being covered in a similar way at the Kuryanovskaya station. Over time, all primary clarifiers will be covered in this way.

However, the process of reconstruction is lengthy - it is impossible to turn off the entire station at once, the settling tanks can only be reconstructed one after another, turning off one by one. And yes, it takes a lot of money. Therefore, until all the sedimentation tanks are covered, the third method of dealing with odors is used - spraying neutralizing substances.

Special sprayers have been installed around the primary clarifiers, which create a cloud of odor neutralizing substances. The substances themselves smell not to say very pleasant or unpleasant, but rather specific, however, their task is not to mask the smell, but to neutralize it. Unfortunately, I did not remember the specific substances that are used, but as they said at the station, these are waste products from the perfume industry in France.

For spraying, special nozzles are used that create particles with a diameter of 5-10 microns. The pressure in the pipes, if I'm not mistaken, is 6-8 atmospheres.

After the primary settling tanks, water enters the aerotanks - long concrete tanks. They supply a huge amount of air through pipes, and also contain activated sludge - the basis of the entire biological method. Activated sludge recycles "waste", while rapidly multiplying. The process is similar to what happens in nature in water bodies, but proceeds many times faster due to warm water, a large amount of air and silt.

Air is supplied from the main machine room, where the turbo blowers are installed. Three turrets above the building are air intakes. The process of supplying air requires a huge amount of electricity, and the interruption of the supply of air leads to catastrophic consequences, because. activated sludge dies very quickly, and its recovery can take months (!).

Aerotanks, oddly enough, do not particularly exude strong unpleasant odors, so it is not planned to cover them.

This photo shows how dirty water enters the aerotank (dark) and mixes with activated sludge (brown).

Some of the facilities are currently disabled and mothballed, for the reasons I wrote about at the beginning of the post - the decrease in water flow in recent years.

After the aerotanks, the water enters the secondary settling tanks. Structurally, they completely repeat the primary ones. Their purpose is to separate activated sludge from already purified water.

Mothballed secondary clarifiers.

Secondary settling tanks do not smell - in fact, there is already clean water.

The water collected in the annular trough of the sump flows into the pipe. Part of the water undergoes additional UV disinfection and merges into the Pekhorka River, while part of the water goes through an underground channel to the Moskva River.

The settled activated sludge is used to produce methane, which is then stored in semi-underground tanks - methane tanks and used at its own thermal power plant.

The spent sludge is sent to sludge sites in the Moscow region, where it is additionally dehydrated and either buried or burned.

Modern ecology, alas, leaves much to be desired - all pollution of biological, chemical, mechanical, organic origin sooner or later penetrate the soil, water bodies. The stocks of "healthy" clean water are becoming smaller every year, in which it plays a certain role permanent use household chemicals, active development of production. Effluent contains a huge amount of toxic impurities, the removal of which must be complex, multilevel.

Used for water treatment different methods- the choice of the optimal one is carried out taking into account the type of pollution, the desired results, the available opportunities.

The easiest option is . It is aimed at removing insoluble components that pollute water - these are fats, solid inclusions. First, the effluents pass through the grates, then the sieves and enter the settling tanks. Small components are precipitated by sand traps, oil products - by petrol and oil traps, grease traps.

A more advanced cleaning method is membrane. It guarantees the most accurate removal of contaminants. involves the use of appropriate organisms that oxidize organic inclusions. The method is based on the natural purification of reservoirs and rivers due to their population with beneficial microflora, which removes phosphorus, nitrogen and other excess impurities. The biological cleaning method can be anaerobic and aerobic. For aerobic, bacteria are needed, the vital activity of which is impossible without oxygen - biofilters, aerotanks filled with activated sludge are installed. The degree of purification, the efficiency is higher than for a biofilter for wastewater treatment. Anaerobic treatment does not require oxygen access.

It involves the use of electrolysis, coagulation, as well as the precipitation of phosphorus with metal salts. Disinfection is carried out by ultraviolet irradiation, chlorine treatment, ozonation. UV disinfection is a much safer and more effective method than chlorination because it does not produce toxic substances. UV radiation is detrimental to all organisms, therefore it destroys all dangerous pathogens. Chlorination is based on the ability of active chlorine to act on microorganisms and destroy them. A significant drawback of the method is the formation of chlorine-containing toxins, carcinogens.

Ozonation involves the disinfection of wastewater with ozone. Ozone is a gas with a triatomic molecular structure, a strong oxidizing agent that kills bacteria. The technique is expensive, it is used with the release of ketones, aldehydes.

Thermal disposal is best suited for process wastewater treatment if other methods are not effective. At modern treatment facilities, wastewater undergoes a multi-component stage-by-stage treatment.

Wastewater treatment plants: requirements for treatment systems, types of treatment facilities

Primary mechanical treatment is always recommended, followed by biological treatment, post-treatment and disinfection of wastewater.

For mechanical cleaning, rods, gratings, sand traps, equalizers, settling tanks, septic tanks, hydrocyclones, centrifuges, flotation plants, degasifiers are used.
Ilosos - special device for water treatment with activated sludge. Other components of the biotreatment system are biocoagulators, sludge pumps, aeration tanks, filters, secondary clarifiers, desilters, filtration fields, biological ponds.
As part of the post-treatment, neutralization and filtration of wastewater are used.
Disinfection, disinfection are carried out by chlorine, electrolysis.

What is meant by waste water?

Waste waters are water masses polluted by industrial waste, for the removal of which from the areas of settlements, industrial enterprises, appropriate sewer systems are used. Effluent also includes water formed as a result of precipitation. Organic inclusions begin to massively rot, which causes a deterioration in the condition of water bodies, air, and leads to a massive spread of bacterial flora. important tasks water treatment for this reason is the organization of drainage, wastewater treatment, prevention of active harm to the environment, human health.

Degree of purification

The level of wastewater pollution should be calculated taking into account the concentration of impurities, expressed as mass per unit volume (g/m3 or mg/l). Domestic sewage is a uniform formula in terms of composition, the concentration of pollutants depends on the volume of water masses consumed, as well as consumption standards.

Degrees and types of pollution of domestic wastewater:

insoluble, large suspensions are formed in them, one particle cannot be more than 0.1 mm in diameter;
suspensions, emulsions, foams, the particle size of which can be from 0.1 µm to 0.1 mm;
colloids - particle sizes in the range of 1 nm-0.1 µm;
soluble with molecularly dispersed particles, the size of which is not more than 1 nm.

Pollutants are also divided into organic, mineral, biological. Minerals are slags, clay, sand, salts, alkalis, acids, etc. Organics are plant or animal, namely the remains of plants, vegetables, fruits, vegetable oils, paper, feces, tissue particles, gluten. Biological impurities - microorganisms, fungi, bacteria, algae.

Approximate proportions of pollutants in domestic wastewater:

mineral - 42%;
organic - 58%;
suspension - 20%;
colloidal impurities - 10%;
dissolved substances - 50%.

The composition of industrial effluents, the level of their pollution are indicators that vary depending on the nature of a particular production, the conditions for the use of effluents in the technological process.

Atmospheric runoff is affected by the climate, the relief of the territory, the nature of buildings, the type of road surface.

The principle of operation of cleaning systems, the rules for their installation and maintenance. Requirements for cleaning systems

Water treatment facilities must provide the specified epidemic and radiation indicators, have a balanced chemical composition. Water after entering the water treatment facilities undergoes a complex biological, mechanical purification. To remove debris, drains are passed through a grate with rods. Cleaning is automatic, and every hour the operators check the quality of the removal of contaminants. There are self-cleaning new grates, but they are more expensive.

For clarification, clarifiers, filters, sedimentation tanks are used. In settling tanks, clarifiers, water moves very slowly, as a result of which suspended particles begin to fall out with the formation of sediment. From the sand traps, the liquid is directed to the primary settling tanks - mineral impurities also settle here, light suspensions rise to the surface. Sediment is obtained at the bottom, it is raked into pits by a truss with a scraper. Floated substances are sent to the grease trap, from there to the well and rolled back.

The clarified water masses are sent to the patches, then to the aeration tanks. On this, the mechanical removal of impurities can be considered complete - the turn of the biological comes. The aerotanks include 4 corridors, the first one is supplied with silt through the tubes, and the water acquires a brown tint, continuing to be actively saturated with oxygen. Microorganisms live in the sludge, which also purify the water. Then the water is fed to the secondary clarifier, where it is separated from the sludge. Silt goes through pipes to wells, from there pumps pump it into aeration tanks. Water is poured into contact-type tanks, where it was previously chlorinated, but now in transit.

It turns out that during the initial purification, water is simply poured into the vessel, infused and drained. But this is precisely what makes it possible to remove most of the organic impurities at minimal financial cost. After leaving the primary settling tanks, water passes to other water treatment facilities. Secondary purification involves the elimination of organic residues. This is the biological stage. The main types of systems are activated sludge, drip biological filters.

The principle of operation of the wastewater treatment complex (general characteristics of water treatment facilities)

Through three collectors from the city, dirty water is supplied to mechanical grates ( the optimal clearance is 16 mm) passes through them, the largest polluting particles are deposited on the grate. Cleaning is automatic. Mineral impurities, which have a significant mass compared to water, follow the hydraulic elevators, after which the hydraulic elevators roll back to the launch pads.

After leaving the sand traps, water enters the primary sedimentation tank (there are 4 in total). Floated substances are fed into the grease trap, from the grease trap already into the well and rolled back. All principles of operation described in this section are valid for treatment systems different types, but may have certain variations, taking into account the characteristics of a particular complex.

Important: types of wastewater

To choose the right treatment system, be sure to consider the type of wastewater. Available options:

Household and fecal or household - they are removed from toilets, bathrooms, kitchens, baths, canteens, hospitals.
Industrial, manufacturing, involved in the implementation of various technological processes such as washing raw materials, products, cooling equipment, pumped out during mining.
Atmospheric wastewater, including rainwater, melted water, those left after watering the streets, green plantings. The main pollutants are minerals.

For a comfortable life in a private house with a kitchen, several bathrooms and showers, a reliable system for collecting, filtering and processing waste resulting from human activity is needed, which would not require frequent pumping and time-consuming for frequent maintenance. If the house does not have the ability to connect to the central sewer, then local treatment facilities become the way out. This article will discuss the principle of operation of an autonomous sewage system of a private house and what advantages and disadvantages such a system has.

The sewer system for a private house can be divided into three types:

septic tank;
local treatment facilities.

Cesspool this is the easiest type of sewer to install and maintain. It involves the discharge of wastewater into a sealed container in which they are stored and from which they are periodically pumped out by a sewage machine. For the construction of a cesspool, as a rule, reinforced concrete rings buried in the ground are used, and access to the pit is organized by installing a hatch. The disadvantages of such a system are the need for regular cleaning of the container, as well as the appearance of an unpleasant odor, which cannot be eliminated even by disinfection.

It is a large container consisting of several cameras communicating with each other. In the first chamber, the waste goes through the stage of primary mechanical cleaning - settling, in which the solid parts settle to the bottom, and the water purified from these parts passes by gravity into the second chamber. Biological cleaning takes place here - anaerobic bacteria process organic compounds, which are in suspension, into the sludge without access to oxygen, further purifying the water.

Since the process of water purification without access to oxygen is not very effective, the output water has a degree of purification of approximately 80%. Even for technical needs such water is unsuitable. For further cleaning, the septic tank involves the use of either aeration fields.

The advantages of such sewerage are autonomy and independence. There is no need to supply electricity to the septic tank, and human intervention is limited to cleaning the system, depending on the intensity of use. But when filtering waste in such systems, methane is released, for the removal of which ventilation is installed with an output not lower than the level of the roofs of houses.

The third type is local treatment plant (VOC or local treatment facilities). Such an installation purifies wastewater with the highest quality with a purification rate of up to 98%. Let's talk in more detail about how autonomous sewage works.

The principle of operation of autonomous sewage

Local treatment facilities are a complex of tanks where wastewater passes through several stages of treatment. A fundamentally autonomous sewage system contains the functions of a septic tank, in which mechanical wastewater treatment takes place, and the functions of aerobic treatment, where aerobic bacteria effectively process a fine suspension into sludge, clarifying the drains as much as possible. Let us consider in detail the principle of operation of LOS.

At the first stage, runoff from the house enter the first chamber of the autonomous sewer, called the reception. The average volume of such a container is 3 cubic meters. Here, as in a septic tank, large particles are settled, as well as the separation of fatty particles with the help of special grease traps.

At the next stage, water flows by gravity into the next chamber, with a volume equal to half of the first chamber. This tank is called an aeration tank, since oxygen is saturated with wastewater here. This happens with the help of an air compressor, which through the hoses pumps oxygen-saturated air into the chamber from below, while mixing due to the many bubbles rising up.

Colonies of bacteria settle in the same chamber, which gradually convert the finely dispersed suspension into activated sludge, eating it and turning it into large enough flakes, which, due to their weight, can settle to the bottom. The high activity of such bacteria is due to the constant supply of oxygen to the aerotank.

All this mixture of liquid and activated sludge mixed in it gradually moves by gravity into the next tank - the secondary sedimentation tank, in which the sludge settles on a special cone-shaped trap, and then is pumped back to the aeration tank. Purified water, separated from sludge, enters the next stage of purification.

When the maximum amount of waste sludge accumulates in the aeration tank, the system automatically pumps it into a special sump, from which it is removed and used for household needs.

After the secondary sump, already sufficiently purified water enters the next tank, coming into contact with a chlorine-containing preparation. Here the final disinfection of wastewater and their post-treatment takes place. At this stage, the water is purified up to 98%, starting to meet sanitary standards.

Removal of treated water from an autonomous sewer can occur in several ways:

Overflowing into a special storage well, from where the water will be pumped out by a pump or used for household needs. This method is used when high level occurrence of groundwater or, if necessary, technical water for watering the garden.
Overflow to where the water will go into the ground. This method is possible if there is sandy or loamy soil on the site. The advantage here is that there is no need to pump out wastewater.
Organization. This method is also used at a low level of groundwater. The advantage of aeration fields is the additional fertilization of the soil at the place of discharge of treated water.

Due to the intensive processing process, autonomous sewage has the smallest dimensions compared to conventional septic tanks, which indicates the convenience of its installation on the site. Purified water can be used for irrigation on the site without fear of any harmful substances entering the soil, and recycled sludge is useful fertilizer, which is used in the garden and vegetable garden, you can scoop it out yourself with buckets.

VOC is a closed installation in which cleaning is carried out inside the chambers and does not require direct human intervention. The filter elements and the grease trap are cleaned approximately once every 6 months, and a preventive visual inspection of the chambers is carried out once a month. Pumps may need to be replaced after several years of operation.

The main disadvantage of the station is the need for uninterrupted power supply. With a prolonged power outage, some filter elements may become unusable.

How to choose an autonomous sewer for your home

For a rational choice of the type of local treatment facilities, a number of factors must be taken into account: the condition and composition of the soil in which the sewage system will be installed, groundwater, the shape and size of the site, the number of people living in the house, is the dwelling seasonal or permanent.

The choice between a septic tank and a VOC will be justified if we calculate the most common situations:

Budget. If it is limited, then a septic tank should be installed. It is cheaper and requires less money to maintain.
Ground water. If their level on the site is high, then the installation of a septic tank becomes impossible, since there will be no possibility of installing structures additional cleaning(equipment of filtration wells and pits in this case will be costly and require a large amount of work). The advantage of VOCs is obvious - the water at the outlet will not be dangerous to the environment.
Electricity supply. With frequent shutdowns and power outages, the installation of an autonomous sewage system is not recommended. When the system stops, filters can fail and bacteria can die. Refueling and repairing such a system is an expensive procedure. It is possible to install a backup power source, but it would be preferable in this case to use a septic tank-based sewer.
Seasonal accommodation. If the owners live in the house only part of the year, then the choice falls in favor of a septic tank. Long breaks in work can adversely affect the operation of local treatment facilities, and the operation of electrical systems of autonomous sewerage in vain will lead to unnecessary financial costs.

Thus, autonomous sewage is the most progressive way to treat wastewater in a private house. The only downside is the cost of the equipment. It is also worth remembering that VOCs require electricity to operate, and when it is turned off, the device will work like a septic tank. Therefore, the final choice, taking into account all the pros and cons, remains with the owner of the house.

This affiliated undertaking petrochemical company SIBUR, is one of the largest producers of high-quality rubbers, latexes and thermoplastic elastomers in Russia.

01 . Our guide to the world of high technologies for the treatment of waste, technological and, of course, sewer water, Ksenia, a press officer, deals with security. After a short hitch, we are still allowed into the territory.

02 . Appearance complex. Part of the cleaning process takes place inside the building, but some stages are also in the open air.

03 . I’ll make a reservation right away that this complex processes only the wastewater from Voronezhsintezkauchuk and does not touch the city sewerage, so readers who are chewing at the moment, in principle, do not have to worry about their appetite. When I heard about this, I was a little upset, so I wanted to know from service personnel about mutant rats, corpses and other horrors. So, one of the two supply pressure pipelines with a diameter of 700 mm (the second is a backup).

04 . First of all, wastewater enters the mechanical treatment area. It includes 4 units of mechanical wastewater treatment Rotamat Ro5BG9 from HUBER (3 in operation, 1 in standby), combining fine-open drum screens and highly efficient aerated sand traps. Waste from the grates and sand after pressing are fed by conveyors into bins with a sluice gate. Waste from the screens is sent to the MSW landfill, but can also be used as filler for sludge composting. Sand is stored on special sand platforms.

05 . In addition to Ksenia, we were accompanied by the head of the workshop Alexander Konstantinovich Charkin. He said he didn't like to be photographed, so just in case, I clicked him when he enthusiastically told us how sand traps work.

06 . In order to smooth out the uneven flow of industrial wastewater from an enterprise, it is necessary to average wastewater by volume and composition. Therefore, due to the cyclical fluctuations in the concentration and composition of pollutants, further water enters the so-called equalizers. There are two of them here.

07 . They are equipped with mechanical wastewater mixing systems. The total capacity of two equalizers is 7580 m3.

08 . You can try to blow off the foam.

09 . After averaging in terms of volume and composition, wastewater is fed by submersible pumps for treatment to flotators.

10 . Flotation units are 4 flotation units (3 in operation, 1 in reserve). Each flotation tank is equipped with a flocculator, a thin-layer settling tank, control and measuring and dosing equipment, an air compressor, a recirculating water supply system, etc.

11 . They saturate part of the water with air and supply a coagulant to remove latex and other suspended solids.

12 . Pressure flotation allows you to separate light suspended solids or emulsions from the liquid phase using air bubbles and reagents. Aluminum hydroxochloride is used as a coagulant (about 10 g/m3 of wastewater).

13 . To reduce reagent consumption and increase flotation efficiency, a cationic flocculant is used, for example, Zetag 7689 (about 0.8 g/m3).

14 . Shop for mechanical sludge dewatering (MSD). Here the sludge from the flotators and activated sludge are dehydrated after biological treatment and post-cleaning.

15 . Mechanical sludge dehydration is carried out on belt filter presses (web width 2 m) with the addition of a working solution of a cationic flocculant. In emergency situations, the sludge is fed to emergency sludge sites.

16 . The dehydrated sludge is sent for disinfection and final drying to a turbo dryer (VOMM Ecologist-900) with a final moisture content of 20%, or to storage sites.

17 .

18 . The filtrate and dirty wash water are drained into the dirty water tank.

19 . Unit for preparation and dosing of the working solution of the flocculant.

20 . Behind the green door from the previous photo is an autonomous boiler room.

21 . Biological treatment according to the project is carried out on biotanks using feed material KS-43 KPP/1.2.3 produced by Ecopolymer. Biotenki - 2-corridor with a corridor size of 54x4.5x4.4 m (capacity of each - 2100 m3). With transverse sectioning by installing light partitions. With the placement of containers with fixed biomass carriers and a polymeric aeration system. Unfortunately, I completely forgot to take a picture of them closer.

22. Blower station. Equipment - centrifugal blowers Q = 7000 m3/h, 3 pcs. (2 - in operation, 1 - in reserve). Air is used for aeration and regeneration of the biotank load, as well as for washing the post-treatment filters.

23 . Post-treatment is carried out on fast non-pressure sand filters.

24 . Number of filters - 10 pcs. The number of sections in the filter is two. Dimensions of one filter section: 5.6x3.0 m.
The useful filtering area of one filter is 16.8 m2.

25 . The filter load is quartz sand with an equivalent diameter of 4 mm, the layer height is 1.4 m. The amount of feed material per filter is 54 m3, the volume of gravel is 3.4 m3 (unfractionated gravel 0.2 m high).

26 . Further, the treated wastewater is disinfected at the TAK55M 5-4x2i1 UV unit (option with post-treatment) manufactured by Wedeco.

27 . Plant productivity 1250 m3/h.

28 . Wash water from biotanks, fast filters, sludge water from sludge thickeners, filtrate, wash water from the CMO are accumulated in the dirty water reservoir.

29 . Perhaps this is the most colorful place we have seen =)

30 . From the reservoir, water is supplied for clarification to radial settling tanks. Serve for clarification of sewage of on-site sewerage: filtrate and washing water of sludge mechanical dewatering, drains from biotank emptying during regeneration, dirty washing water from post-treatment filters, sludge water from sealers. The clarified waters are sent to the biotanks, the sludge is sent to the sludge thickener (in emergency situations, directly to the sludge mixing tank in front of the CMO). The removal of floating substances is maintained.

31 . There are two of them. One was full and fragrant.

32. And the second was actually empty.

33 . MCC

34 . Operator.

35 . Basically, that's all. The cleaning process is completed. After UV disinfection, water enters the collection chamber, and from it - through a gravity collector further to the place of discharge into the Voronezh reservoir. The described technological process fully ensures the fulfillment of the requirements for the quality of treated wastewater discharged into a surface reservoir for fisheries. And let this picture serve as a group photo for the memory of the participants of the excursion.

- This is a complex of special facilities designed to treat wastewater from the contaminants contained in them. Purified water is either used in the future, or discharged into natural reservoirs (Great Soviet Encyclopedia).

Each settlement needs effective treatment facilities. The operation of these complexes depends on what kind of water will enter the environment and how it will affect the ecosystem in the future. If liquid waste is not treated at all, then not only plants and animals will die, but the soil will also be poisoned, and harmful bacteria can enter the human body and cause serious consequences.

Each enterprise that has toxic liquid waste is obliged to deal with a system of treatment facilities. Thus, it will affect the state of nature, and improve the conditions of human life. If the treatment complexes work effectively, then the wastewater will become harmless when it enters the ground and water bodies. The size of treatment facilities (hereinafter referred to as O.S.) and the complexity of treatment are highly dependent on the contamination of wastewater and their volumes. In more detail about the stages of wastewater treatment and types of O.S. read on.

Stages of wastewater treatment

The most indicative in terms of the presence of stages of water purification are urban or local OS, designed for large settlements. It is domestic wastewater that is the most difficult to clean, as it contains heterogeneous pollutants.

For facilities for the purification of water from sewerage, it is characteristic that they line up in a certain sequence. Such a complex is called a line of treatment facilities. The scheme begins with mechanical cleaning. Here gratings and sand traps are most often used. This is the initial stage of the entire water treatment process.

It can be the remains of paper, rags, cotton wool, bags and other debris. After gratings, sand traps come into operation. They are necessary in order to retain sand, including large sizes.

Mechanical Stage Wastewater Treatment

Initially, all water from the sewer enters the main pumping station into a special tank. This tank is designed to compensate for the increased load during peak hours. A powerful pump evenly pumps the appropriate volume of water to pass through all stages of cleaning.

catch large debris over 16 mm - cans, bottles, rags, bags, food, plastic, etc. In the future, this garbage is either processed on site or taken to the places of processing of solid household and industrial waste. Lattices are a type of transverse metal beams, the distance between which is equal to several centimeters.

In fact, they catch not only sand, but also small pebbles, glass fragments, slag, etc. Sand rather quickly settles to the bottom under the influence of gravity. Then the settled particles are raked by a special device into a recess at the bottom, from where it is pumped out by a pump. The sand is washed and disposed of.

. Here all impurities that float to the surface of the water (fats, oils, oil products, etc.) are removed, etc. By analogy with a sand trap, they are also removed with a special scraper, only from the surface of the water.

4. Sumps- an important element of any line of treatment facilities. They release water from suspended solids, including helminth eggs. They can be vertical and horizontal, single-tier and two-tier. The latter are the most optimal, since at the same time the water from the sewer in the first tier is cleaned, and the sediment (silt) that has formed there is discharged through a special hole into the lower tier. How does the process of releasing water from the sewer from suspended solids take place in such structures? The mechanism is quite simple. Sedimentation tanks are large round or rectangular tanks where substances settle under the action of gravity.

To speed up this process, you can use special additives - coagulants or flocculants. They contribute to the adhesion of small particles due to a change in charge, larger substances are deposited faster. Thus, sedimentation tanks are indispensable facilities for purifying water from sewers. It is important to consider that with simple water treatment they are also actively used. The principle of operation is based on the fact that water enters from one end of the device, while the diameter of the pipe at the exit becomes larger and the fluid flow slows down. All this contributes to the deposition of particles.

mechanical wastewater treatment can be used depending on the degree of water pollution and the design of a particular treatment plant. These include: membranes, filters, septic tanks, etc.

If we compare this stage with conventional water treatment for drinking purposes, then in the latter version such facilities are not used, they are not necessary. Instead, the processes of clarification and discoloration of water occur. Mechanical cleaning is very important, as in the future it will allow more efficient biological cleaning.

Biological wastewater treatment plants

Biological treatment can be both an independent treatment facility and an important stage in a multi-stage system of large urban treatment facilities.

The essence of biological treatment is to remove various pollutants (organics, nitrogen, phosphorus, etc.) from water with the help of special microorganisms (bacteria and protozoa). These microorganisms feed on harmful contaminants contained in the water, thereby purifying it.

From a technical point of view, biological treatment is carried out in several stages:

- a rectangular tank where water after mechanical cleaning is mixed with activated sludge (special microorganisms), which cleans it. Microorganisms are of 2 types:

Aerobic using oxygen to purify water. When using these microorganisms, the water must be enriched with oxygen before it enters the aerotank.
Anaerobic– NOT using oxygen for water treatment.

It is necessary to remove unpleasantly smelling air with its subsequent purification. This workshop is necessary when the volume of wastewater is large enough and / or treatment facilities are located near settlements.

Here, water is purified from activated sludge by settling it. Microorganisms settle to the bottom, where they are transported to the pit with the help of a bottom scraper. To remove floating sludge, a surface scraper mechanism is provided.

The treatment scheme also includes sludge digestion. Of the treatment facilities, the methane tank is important. It is a tank for the digestion of sediment, which is formed during settling in two-tiered primary clarifiers. During the digestion process, methane is produced, which can be used in other technological operations. The resulting sludge is collected and transported to special sites for thorough drying. Sludge beds and vacuum filters are widely used for sludge dehydration. After that, it can be disposed of or used for other needs. Fermentation occurs under the influence of active bacteria, algae, oxygen. Biofilters may also be included in the sewerage water treatment scheme.

It is best to place them before the secondary settling tanks, so that substances that have been carried away with the flow of water from the filters can be deposited in the settling tanks. It is advisable to use so-called pre-aerators to speed up cleaning. These are devices that contribute to the saturation of water with oxygen to accelerate the aerobic processes of oxidation of substances and biological treatment. It should be noted that the purification of water from the sewerage is conditionally divided into 2 stages: preliminary and final.

The system of treatment facilities may include biofilters instead of filtration and irrigation fields.

- These are devices where wastewater is purified by passing through a filter containing active bacteria. It consists of solid substances, which can be used as granite chips, polyurethane foam, polystyrene and other substances. A biological film consisting of microorganisms forms on the surface of these particles. They decompose organic matter. Biofilters need to be cleaned periodically as they get dirty.

Wastewater is fed into the filter in a dosed manner, otherwise a large pressure can kill beneficial bacteria. After biofilters, secondary clarifiers are used. The sludge formed in them enters partly into the aerotank, and the rest of it goes to the sludge thickeners. The choice of one or another method of biological treatment and the type of treatment facilities largely depends on the required degree of wastewater treatment, topography, soil type and economic indicators.

Post-treatment of wastewater

After passing the main stages of treatment, 90-95% of all contaminants are removed from wastewater. But the remaining pollutants, as well as residual microorganisms and their metabolic products, do not allow this water to be discharged into natural reservoirs. In this regard, various systems for post-treatment of wastewater were introduced at treatment facilities.

In bioreactors, the following pollutants are oxidized:

organic compounds that were "too tough" for microorganisms,
these microorganisms themselves
ammonium nitrogen.

This happens by creating conditions for the development of autotrophic microorganisms, i.e. converting inorganic compounds into organic ones. For this, special plastic charging disks with a high specific surface area are used. Simply put, these discs have a hole in the center. Intensive aeration is used to speed up the processes in the bioreactor.

Filters purify water with sand. The sand is continuously updated automatically. Filtration is carried out at several installations by supplying water to them from the bottom up. In order not to use pumps and not to waste electricity, these filters are installed at a level lower than other systems. Filter washing is designed in such a way that it does not require a large amount of water. Therefore, they do not occupy such a large area.

Disinfection of water with ultraviolet light

Disinfection or disinfection of water is an important component that ensures its safety for the reservoir into which it will be discharged. Disinfection, that is, the destruction of microorganisms, is the final step in the purification of sewage effluents. A wide variety of methods can be used for disinfection: ultraviolet irradiation, alternating current, ultrasound, gamma irradiation, chlorination.

UVR is a very effective method by which approximately 99% of all microorganisms are destroyed, including bacteria, viruses, protozoa, helminth eggs. It is based on the ability to destroy the bacterial membrane. But this method is not widely used. In addition, its effectiveness depends on the turbidity of the water, the content of suspended solids in it. And UVI lamps quite quickly become covered with a coating of mineral and biological substances. To prevent this, special emitters of ultrasonic waves are provided.

The most commonly used method of chlorination after sewage treatment plants. Chlorination can be different: double, superchlorination, with preammonization. The latter is necessary to prevent an unpleasant odor. Superchlorination involves exposure to very large doses of chlorine. Dual action is that chlorination is carried out in 2 stages. This is more typical for water treatment. The method of chlorinating water from the sewer is very effective, in addition, chlorine has an aftereffect that other cleaning methods cannot boast of. After disinfection, the waste is discharged into a reservoir.

Phosphate removal

Phosphates are salts of phosphoric acids. They are widely used in synthetic detergents ( washing powders, dishwashing detergents, etc.). Phosphates, getting into water bodies, lead to their eutrophication, i.e. turning into a swamp.

Wastewater treatment from phosphates is carried out by dosed addition of special coagulants to water in front of biological treatment facilities and in front of sand filters.

Auxiliary premises of treatment facilities

Aeration shop

- this is an active process of saturating water with air, in this case by passing air bubbles through the water. Aeration is used in many processes in wastewater treatment plants. Air is supplied by one or more blowers with frequency converters. Special oxygen sensors regulate the amount of air supplied so that its content in the water is optimal.

Disposal of excess activated sludge (microorganisms)

At the biological stage of wastewater treatment, excess sludge is formed, since microorganisms actively multiply in the aeration tanks. Excess sludge is dehydrated and disposed of.

The dehydration process takes place in several stages:

In excess sludge is added special reagents, which stop the activity of microorganisms and contribute to their thickening
IN sludge thickener the sludge is compacted and partially dehydrated.
On centrifuge the sludge is squeezed out and the remaining moisture is removed from it.
Inline dryers with the help of continuous circulation of warm air, the sludge is finally dried. The dried sludge has a residual moisture content of 20-30%.
Then ooze packed in sealed containers and disposed of
The water removed from the sludge is sent back to the beginning of the purification cycle.

Air cleaning

Unfortunately, the sewage treatment plant does not smell the best. Particularly smelly is the stage of biological wastewater treatment. Therefore, if the treatment plant is located near settlements or the volume of wastewater is so large that there is a lot of bad-smelling air, you need to think about cleaning not only water, but also air.

Air purification, as a rule, takes place in 2 stages:

Initially, polluted air is fed into bioreactors, where it comes into contact with specialized microflora adapted for the utilization of organic substances contained in the air. It is these organic substances that cause the bad smell.
The air goes through the stage of disinfection with ultraviolet light to prevent these microorganisms from entering the atmosphere.

Laboratory at the wastewater treatment plant

All water that leaves the treatment plant must be systematically monitored in the laboratory. The laboratory determines the presence of harmful impurities in the water and the compliance of their concentration with the established standards. In case of exceeding one or another indicator, the workers of the treatment plant conduct a thorough inspection of the corresponding stage of treatment. And if a problem is found, they fix it.

Administrative and amenity complex

The personnel serving the treatment plant can reach several tens of people. For their comfortable work, an administrative and amenity complex is being created, it includes:

Equipment repair shops
Laboratory
control room
Offices of administrative and managerial personnel (accounting departments, personnel service, engineering, etc.)
Head office.

Power supply O.S. performed according to the first category of reliability. Since the long stoppage of O.S. due to lack of electricity can cause the output of O.S. out of service.

To prevent emergencies power supply O.S. comes from several independent sources. In the department of the transformer substation, the input of a power cable from the city power supply system is provided. As well as the input of an independent source of electric current, for example, from a diesel generator, in case of an accident in the city power grid.

Conclusion

Based on the foregoing, it can be concluded that the scheme of treatment facilities is very complex and includes various stages of wastewater treatment from sewers. First of all, you need to know that this scheme applies only to domestic wastewater. If there are industrial effluents, then in this case they additionally include special methods that will be aimed at reducing the concentration of hazardous chemicals. In our case, the cleaning scheme includes the following main stages: mechanical, biological cleaning and disinfection (disinfection).

Mechanical cleaning begins with the use of gratings and sand traps, in which large debris (rags, paper, cotton wool) is retained. Sand traps are needed to settle excess sand, especially coarse sand. This is of great importance for the next steps. After gratings and grit traps, the sewerage treatment plant scheme includes the use of primary clarifiers. Suspended matter settles in them under the force of gravity. Coagulants are often used to speed up this process.

After the settling tanks, the filtration process begins, which is carried out mainly in biofilters. The mechanism of action of the biofilter is based on the action of bacteria that destroy organic matter.

The next stage is secondary settling tanks. In them, the silt, which was carried away with the current of the liquid, settles. After them, it is advisable to use a digester, in which the sediment is fermented and transported to sludge sites.

The next stage is biological treatment with the help of an aeration tank, filtration fields or irrigation fields. The final step is disinfection.

Types of treatment facilities

A variety of facilities are used for water treatment. If it is planned to carry out these works in relation to surface waters immediately before they are supplied to the distribution network of the city, then the following facilities are used: sedimentation tanks, filters. For wastewater, a wider range of devices can be used: septic tanks, aeration tanks, digesters, biological ponds, irrigation fields, filtration fields, and so on. Wastewater treatment plants are of several types depending on their purpose. They differ not only in the volume of treated water, but also in the presence of stages of its purification.

City wastewater treatment plant

Data from O.S. are the largest of all, they are used in large metropolitan areas and cities. In such systems, especially effective methods liquid treatment, such as chemical treatment, methane tanks, flotation plants They are designed for the treatment of municipal wastewater. These waters are a mixture of domestic and industrial wastewater. Therefore, there are a lot of pollutants in them, and they are very diverse. The waters are purified to the standards for discharge into a fishery reservoir. The standards are regulated by the order of the Ministry of Agriculture of Russia dated December 13, 2016 No. 552 “On approval of water quality standards for water bodies of fishery significance, including standards for maximum permissible concentrations of harmful substances in the waters of water bodies of fishery significance”.

On O.S. data, as a rule, all stages of water purification described above are used. The most illustrative example is the Kuryanovsk treatment facilities.

Kuryanovskie O.S. are the largest in Europe. Its capacity is 2.2 million m3/day. They serve 60% of wastewater in the city of Moscow. The history of these objects goes back to the distant 1939.

Local treatment facilities

Local treatment facilities are facilities and devices designed to treat the subscriber's wastewater before they are discharged into the public sewer system (the definition is given by Decree of the Government of the Russian Federation of February 12, 1999 No. 167).

There are several classifications of local O.S., for example, there are local O.S. connected to the central sewerage and autonomous. Local O.S. can be used on the following objects:

In small towns
In the settlements
In sanatoriums and boarding houses
At car washes
On household plots
At manufacturing plants
And on other objects.

Local O.S. can be very different from small units to permanent structures that are serviced daily by qualified personnel.

Treatment facilities for a private house.

Several solutions are used for the disposal of wastewater from a private house. All of them have their advantages and disadvantages. However, the choice always remains with the owner of the house.

1. Cesspool. In truth, this is not even a treatment plant, but simply a reservoir for temporary storage of wastewater. When the pit is filled, a sewage truck is called in, which pumps out the contents and transports it for further processing.

This archaic technology is still used today because of its cheapness and simplicity. However, it also has significant drawbacks, which, at times, nullify all its advantages. Wastewater can enter the environment and groundwater, thereby polluting them. For a sewage truck, it is necessary to provide for a normal entrance, since it will have to be called quite often.

2. Drive. It is a container made of plastic, fiberglass, metal or concrete, where wastewater is drained and stored. Then they are pumped out and disposed of by a sewage machine. The technology is similar to a cesspool, but the waters do not pollute the environment. The disadvantage of such a system is the fact that in the spring, with a large amount of water in the soil, the drive can be squeezed out to the surface of the earth.

3. Septic tank- is a large container, in which substances such as coarse dirt, organic compounds, stones and sand precipitate, and elements such as various oils, fats and petroleum products remain on the surface of the liquid. Bacteria that live inside the septic tank extract oxygen for life from the precipitated sludge, while reducing the level of nitrogen in the wastewater. When the liquid leaves the sump, it becomes clarified. Then it is cleaned with bacteria. However, it is important to understand that phosphorus remains in such water. For the final biological treatment, irrigation fields, filtration fields or filter wells can be used, the operation of which is also based on the action of bacteria and activated sludge. It will not be possible to grow plants with a deep root system in this area.

A septic tank is very expensive and can take up a large area. It should be borne in mind that this is a facility that is designed to treat a small amount of domestic wastewater from the sewer. However, the result is worth the money spent. The septic tank device is more clearly shown in the figure below.

4. Stations for deep biological treatment are already a more serious treatment plant, unlike a septic tank. This device requires electricity to operate. However, the quality of water purification is up to 98%. The design is quite compact and durable (up to 50 years of operation). To service the station at the top, above the ground, there is a special hatch.

Stormwater treatment plants

Despite the fact that rainwater is considered quite clean, however, it collects various harmful elements from asphalt, roofs and lawns. Garbage, sand and oil products. In order to prevent all this from falling into the nearest reservoirs, stormwater treatment facilities are being created.

In them, water undergoes mechanical purification in several stages:

Sump. Here, under the influence of the gravity of the Earth, large particles settle to the bottom - pebbles, glass fragments, metal parts, etc.
thin layer module. Here, oils and oil products are collected on the surface of the water, where they are collected on special hydrophobic plates.
Sorption fibrous filter. It captures everything that the thin layer filter missed.
coalescent module. It contributes to the separation of particles of oil products that float to the surface, the size of which is greater than 0.2 mm.
Coal filter aftertreatment. It finally rids the water of all oil products that remain in it after passing through the previous stages of purification.

Design of treatment facilities

Design O.S. determine their cost, choose the right treatment technology, ensure the reliability of the structure, bring wastewater to quality standards. Experienced specialists will help you find effective plants and reagents, draw up a wastewater treatment scheme and put the plant into operation. Another important point is the preparation of a budget that will allow you to plan and control costs, as well as make adjustments if necessary.

For the project O.S. The following factors are strongly influenced:

Waste water volumes. The design of facilities for a personal plot is one thing, but the design of facilities for wastewater treatment of a cottage village is another. Moreover, it must be taken into account that the possibilities of O.S. must be greater than the current amount of wastewater.
Locality. Wastewater treatment facilities require the access of special vehicles. It is also necessary to provide for the power supply of the facility, the disposal of purified water, the location of the sewerage system. O.S. can occupy a large area, but they should not interfere with neighboring buildings, structures, road sections and other structures.
Waste water pollution. Storm water treatment technology is very different from household water treatment.
Required level of cleaning. If the customer wants to save on the quality of treated water, then it is necessary to use simple technologies. However, if it is necessary to discharge water into natural reservoirs, then the quality of treatment must be appropriate.
Competence of the performer. If you order O.S. from inexperienced companies, then get ready for unpleasant surprises in the form of an increase in construction estimates or a septic tank that floated up in the spring. This happens because the project forgets to include enough critical points.
Technological features. The technologies used, the presence or absence of treatment stages, the need to build systems serving the treatment plant - all this should be reflected in the project.
Other. It is impossible to foresee everything in advance. As the treatment plant is being designed and installed, various changes may be made to the draft plan that could not have been foreseen at the initial stage.

Stages of designing a treatment plant:

Preliminary work. They include studying the object, clarifying the wishes of the customer, analyzing wastewater, etc.
Collection of permits. This item is usually relevant for the construction of large and complex structures. For their construction, it is necessary to obtain and agree on the relevant documentation from supervisory authorities: MOBVU, MOSRYBVOD, Rosprirodnadzor, SES, Hydromet, etc.
Choice of technology. Based on paragraphs 1 and 2, the necessary technologies used for water purification are selected.
Drawing up a budget. Construction costs O.S. must be transparent. The customer must know exactly how much the materials cost, what is the price of the installed equipment, what wage fund for workers, etc. You should also take into account the cost of subsequent maintenance of the system.
cleaning efficiency. Despite all calculations, the cleaning results may be far from desired. Therefore, already at the planning stage, O.S. need to experiment and laboratory research, which will help to avoid unpleasant surprises after the completion of construction.
Development and approval of project documentation. To start the construction of treatment facilities, it is necessary to develop and agree on the following documents: a draft sanitary protection zone, a draft standard for permissible discharges, a draft maximum permissible emissions.

Installation of treatment facilities

After the project O.S. was prepared and necessary permissions have been received, the installation stage begins. Although the installation of a country septic tank is very different from the construction of a treatment plant in a cottage village, they still go through several stages.

First, the terrain is being prepared. A pit is being dug for the installation of a treatment plant. The floor of the pit is covered with sand and tamped or concreted. If the treatment plant is designed for a large number of wastewater, then, as a rule, it is built on the surface of the earth. In this case, the foundation is poured and a building or structure is already installed on it.

Secondly, the installation of equipment is carried out. It is installed, connected to the sewerage and drainage system, to electrical network. This stage is very important because it requires the personnel to know the specifics of the operation of the configured equipment. It is improper installation that most often causes equipment failure.

Thirdly, checking and handing over the object. After installation, the finished treatment plant is tested for the quality of water treatment, as well as for the ability to work in conditions of increased load. After checking O.S. is handed over to the customer or his representative, and, if necessary, passes the procedure of state control.

Maintenance of treatment facilities

Like any equipment, a sewage treatment plant also needs maintenance. First of all from O.S. it is necessary to remove large debris, sand, as well as excess sludge that are formed during cleaning. On large O.S. the number and type of elements to be removed can be much larger. But in any case, they will have to be removed.

Secondly, the performance of the equipment is checked. Malfunctions in any element can be fraught not only with a decrease in the quality of water purification, but also with the failure of all equipment.

Thirdly, in case of detection of a breakdown, the equipment is subject to repair. And it's good if the equipment is under warranty. If the warranty period has expired, then the repair of O.S. will have to be done at your own expense.