Local sewage and storm water treatment facilities. Local wastewater treatment plants - what is it? Local sewage treatment plants

Sewage treatment facilities are necessary for the rational disposal of waste, domestic and storm water. If these structures do not function properly, significant harm can be caused to the environment. That is why the work of sewer systems is regulated and controlled at the legislative level.

The principle of operation of the sewer structure

The sewerage system may include a variety of devices. But, despite this, waste treatment is carried out according to a certain algorithm.

First stage

At the first stage, wastewater is purified mechanically. The retention of large contaminants, which are of mineral and organic origin, is carried out by gratings and sieve. Sand traps are used to filter smaller particles - broken glass, sand and slag. The membrane device performs more thorough cleaning. Suspended solids are separated in the settling tank. This removes mineral contaminants.

Second phase

At the next stage, biological agents are used for cleaning. Organic compounds decompose under the influence of particularly active bacteria. The liquid is passed through a biofilter. As a result, sludge and gaseous compounds are formed.

Third stage

At the final stage of wastewater disinfection, additional chemical compounds are used. The resulting liquid can already be used for technical purposes.

Types of sewer systems

Sewage treatment facilities are designed before the start of construction work. It is important to choose the right sewer design that can solve the waste disposal tasks and have a sufficient level of performance. Today, wastewater treatment can be done using the following devices:

• local cleaning devices;
• individual autonomous structures;
• block systems and modules.

Local cleaning systems

Local treatment facilities are structures that are used to clean and collect waste at facilities of various sizes. They can have household or industrial purposes and are the basis.

In classical treatment devices, the speed of movement of wastewater decreases with distance from the discharge site. There is a gradual settling of solid particles to the bottom. Removal of other impurities is carried out by post-treatment systems. Classic treatment facilities require sufficiently large containers in which waste is settled. Such a requirement is difficult to implement in individual buildings.

With the help of local treatment systems, wastewater is collected and treated in private homes or small villages where there is no central sewerage system. Let's look at the most common local constructions.

Use of septic tanks

Septic tanks are often used to install an autonomous sewer system in country houses. They usually take the form of plastic containers. Plastic has the necessary performance characteristics:

• it weighs little - the tanks are easy to transport and install;
• the material can withstand exposure to aggressive environments;
• does not rust;
• has sufficient strength.

Each tank contains a different number of sections that perform specific functions. Some act as a settling tank, while others purify wastewater using biologically active microorganisms. Still others are used for filtering.

Septic tanks are widely used in the construction of private treatment structures. They are convenient to use. They have a long service life. The sewer system can be completely autonomous. In order to increase the level of wastewater treatment, the structure is equipped with additional elements - fields that perform filtration and aeration.

The simplest and most effective septic tank

Aero tanks

These treatment devices are an integral part of large sewerage facilities that process wastewater from industrial enterprises. They look like huge tanks. Water and activated sludge are mixed in containers. Oxygen is used to speed up the reaction. Sometimes aeration tanks are used in the construction of autonomous sewage systems in a private house. In this case they have a small volume. They are usually installed in septic tanks. Aerotanks may include special catchers. They remove fat and petroleum products from wastewater.

Use of biological filters

When installing sewerage systems, biological filters are also used. They are most often used as built-in structures. Biofilters are part of local treatment facilities. In these devices, wastewater is purified using special bacteria. Microorganisms contribute to the accelerated decomposition of sewage. The output produces a liquid that will not harm the environment and can be discharged into the soil.

Storm sewer systems

In local treatment facilities, harmful impurities, inorganic and organic waste are removed from wastewater. The purified liquid is subsequently used to irrigate fields. But in order to collect, transport and purify melt and rainwater, storm sewer treatment facilities are also used. Conventional sewer structures cannot cope with this task.

Stormwater treatment facilities must ensure the safety of the foundation, pavement and lawns surrounding the main structure.

They include pipes, gutters and storm water inlets. Through them, excess water is transported to a common collector.

The system is placed below the soil freezing level. The design contains filters to retain sand and other small particles. Purified liquid must enter the collector.

More refined purification of waste rainwater is carried out using additional devices: a sorption unit and a filter for removing oil products. At the final stage, the purified water is discharged into reservoirs or used to water the garden. It should be taken into account that in this sewer system it is necessary to periodically replace the filtration elements.

Autonomous sewerage structures

The design of autonomous sewage systems is very similar to the design of local treatment facilities. But they also have their own distinctive features. This class of sewer systems includes septic tanks and wastewater collection tanks, in which wastewater is initially accumulated and only then filtered.

Application of block and modular designs

Block and modular sewerage structures carry out deep wastewater treatment. They are more often used in industrial and manufacturing areas. Using such devices, the following tasks are solved:

• a high level of wastewater treatment is ensured;
• the sludge content in the purified liquid decreases;
• the environment is protected from exposure to harmful substances;
• provides the opportunity to reuse water.

Such systems have increased productivity. They can be used to serve entire areas. Used in wide temperature ranges.

Selection of sewer design

To choose the right cleaning system, you need to consider a number of factors:

• total daily fluid intake;
• preferred type of sewer design;
• mode of use of the sewer structure;
• location of the object.

Some devices may work offline. Others require electricity or other forms of energy to function. Certain systems cannot be used when groundwater is close to each other.

When arranging a treatment system, you should be guided by existing sanitary standards. If it is necessary to use a sewer truck to remove waste, it is necessary to provide for the possibility of free access to the waste storage site.

Features of design work

When designing sewage treatment facilities, it is necessary to provide for the occurrence of various situations that may subsequently affect the operational characteristics of the system. It is also necessary to take into account the existing legislative framework.

Its basis is security functions to protect the natural environment. The cleaning system must be located in a sanitary protected area. During the design process, you should pay attention to the following indicators:

• dimensions and volume of the sewer structure;
• optimal type of device;
• location of groundwater;
• soil freezing level;
• system performance;
• cleaning method used;
• optimization of the installation of sewerage devices.

To avoid a conflict with sanitary permitting services later, before constructing a sewerage system, it is necessary to prepare a number of documents:

• agreement on ownership or lease of land;
• layout diagram of the location where the treatment structure is supposed to be placed;
• compliance with existing sanitary standards;
• technical conditions for the use of water resources;
• data on the volume of consumed and utilized water;
• general design of the project;
• description of the wastewater filtration and disposal system.

A permit from the sanitary and epidemiological station must be present. It should be remembered that if sanitary standards for locating an object are violated, the owner may be brought to administrative liability.

Video: Wastewater treatment plants

Convenience has long become an integral part of modern life for every family. But they cannot exist without communications, where all household waste usually goes. For wastewater treatment there are local treatment facilities (WTP) wastewater, which we will discuss in more detail in this article.

Volatile and non-volatile VOCs

Local treatment facilities (LTP) are special structures and units that are used to treat wastewater before being discharged into the communications system. Based on their mode of action, there are two types of VOCs:

• energy dependent;
• non-volatile.

Local sewage treatment plants are designed to filter wastewater biologically. In the first case, so-called aeration tanks are used - containers with a rectangular cross-section through which wastewater passes mixed with activated sludge and where the water mass is actually purified.

The purification of contaminated wastewater is carried out by special bacteria located in an oxygen environment. During this process, oxygen is enriched, pumped by a powerful compressor.

What do local treatment facilities look like?

Volatile VOCs provide a higher level of wastewater treatment than non-volatile VOCs, in which filtration goes through the following stages:

• preliminary water purification occurs in a septic tank;
• additional filtration takes place on special filtration fields and gravel filters.

In addition to differences in design and technical characteristics, when choosing local sewage treatment plants, it is also necessary to take into account the availability of approvals from specialized organizations. So, if your house is located in Moscow or the Moscow region, it is advisable to choose local treatment facilities recommended by Mosvodokanal.

Working principle of VOC

The operating principle of most VOCs is based on stepwise wastewater treatment.

1.Mechanical cleaning

In a megalopolis, the first stage is mechanical filtration, during which heavy, poorly soluble fractions are captured and settled mechanically. If VOC purifies storm drains or industrial sewerage, the first stage will involve cleaning the wastewater from various waste fractions.

After the waste fractions (polyethylene, sand, etc.) are collected in baskets, they are moved to a booker, from where they are delivered to processing plants for waste crushing. After going through this technological process, during which heavy particles settle at the bottom of the sand traps, the sand is further purified (stones are removed). The resulting material is used in construction. Purified water flows into another compartment, where it is cleaned of petroleum products and oils.

At this stage, separators and grease traps come into play. Since fats are lighter than water, they float to the surface and, using air currents, are delivered to special tanks, where they are collected and covered with a crust, after which they are removed mechanically.

2.Biological treatment

The next step is the biological treatment of wastewater. The liquid, purified from heavy fractions and particles, interacts with special bacteria that process “wastewater” into sludge and water. Microorganisms begin to act in the absence of precipitated or floating fractions.

3.Physico-chemical cleaning

At the next stage, the water enters the structures, where it is subject to physical and chemical treatment. The operating principle of such VOCs is simple. “Effluent” is actively processed with chemical compounds that attract the smallest fractions of any origin contained in the water. Thus, the water masses undergo additional filtration and pass to the next element of the local treatment plant for a full purification cycle.

4.Additional cleaning

The final stage is wastewater treatment. At this stage, remaining microorganisms and reagents are removed from the wastewater by passing through sorption filters.

At this stage, the water fully complies with all hygienic parameters and can be used in various fields, except for food industry enterprises.

Classification of VOCs by functional purpose

Purification systems may have different requirements, which depend on the specifics of the objects they serve. Based on their functional purpose, the following VOCs are distinguished:

• VOC for storm drainage.

Devices of this group are manufactured on the basis of special fiberglass containers. They are reliable, resistant to mechanical damage and have a long service life. Moreover, they are easy to install.

• For cleaning domestic wastewater.

VOCs of this group are intended for high-quality and deep purification of wastewater coming from social infrastructure facilities. The equipment is made of steel and other materials that are not susceptible to corrosion. Local treatment facilities can be either stationary or underground.

• For cleaning wastewater from industrial enterprises.

The main difference from other groups of VOCs is the use of harder sludge and chemical reagents.

• Special “drainage” cleaning systems for car washes.

The use of equipment helps reduce water and electricity costs by implementing a return-and-return mechanism of use.

• Water purification devices for infrastructure facilities (cafes, hotels, etc.).

Often, social infrastructure facilities discharge “effluents” with a high concentration of fats into the sewer system, which such units cope well with.

• VOCs for cleaning household wastewater.

The main task is to prevent the release of contaminated wastewater into water bodies, which is fraught with environmental problems and the growth of various types of diseases.

Each of the VOC groups is designed to work in a specific environment. This is due to the specifics of the activities of each specific object. Thus, VOCs operating in large industrial production must have certain properties and technical characteristics.

Where to buy a local treatment plant?

Local treatment facilities are a mandatory attribute of both industrial and domestic facilities. There are many companies on the market that sell and install high-quality VOCs.

The cost of local treatment facilities directly depends on the future “scope of work,” the complexity of installation and the list of tasks to be performed. It is also a prerequisite that the supplier has certificates and the necessary documents for the products. This may increase the cost a little, but since wastewater treatment is a very serious issue, it is better not to skimp on it. Remember, saving on a high-quality cleaning system once can result in large financial costs in the future!

When choosing VOCs, remember: wastewater treatment in a private home is the key to environmental safety!

Modern technologies in the sewerage equipment market have long offered highly professional equipment that is designed to purify sewage to a significantly high degree that meets all the requirements of environmental services.

Such sewerage technology or equipment includes local wastewater treatment plants, or VOCs for short. But in order to have a complete understanding of the structure of such structures, it is necessary to study their internal structure, installation and operating conditions.

It will also be interesting to get acquainted with the approximate cost of such sewerage equipment as VOCs from different manufacturers.

Local treatment facilities (WTP) are structures or sewerage devices that are designed for deep and complete treatment of household liquid waste, storm water, industrial waste, or any other wastewater.

This term was adopted at the state level in Decree of the Government of the Russian Federation dated February 12, 1999 No. 167 “On approval of the Rules for the use of public water supply and sewerage systems in the Russian Federation” and today is widely used among specialists in the installation, construction and maintenance of such systems.

People often simply call VOC - autonomous sewerage. However, this name applies only to those sewer systems that exist and operate separately from the entire branched highway of urban sewer networks.

VOCs usually represent a whole complex of treatment plants and all kinds of systems in order to receive and purify not only household or household wastewater, but also liquid discharges from various industries, industrial enterprises or organizations, as well as wastewater from storm sewers, melted or groundwater.

Important! The primary task of these facilities is to purify wastewater to such an extent that it fully complies with the norms and standards that ensure complete safety for the natural environment, the health of the animal world and people.

What are the VOCs?

Local treatment facilities are usually classified as two types of structures:

• those that are part of the city centralized sewer network - process wastewater and send it to the city sewer network;
• being an autonomous entity - serves the sewer system of one or another autonomous sewer system of a boarding house, sanatorium, restaurant, hotel, private house, cottage or dacha, i.e. those buildings that are located at a great distance from the centralized city sewer network, to which there is no way to connect.

The first group generally includes the largest and largest structures, which include a number of wastewater treatment facilities, forming a whole complex of automated wastewater treatment systems.

These VOCs can be used for both household and industrial purposes. Households receive and purify wastewater from all kinds of population centers in megacities, cities, suburbs or towns.

And industrial VOCs, judging by the name, process and recycle wastewater coming from various types of production, plants, factories or any workshops, that is, industrial enterprises. VOC.

They are large-scale urban sewer structures, built in specially designated areas outside the city limits, surrounded by a sanitary zone, on the territory of which it is forbidden to live, have picnics and other recreational activities.

Such structures must be maintained by special technical personnel and equipment; accordingly, they are energy dependent, since some system devices require power supply: pumps, aeration tanks and other devices for cleaning wastewater.

Photo: city sewer VOCs

And such local treatment facilities as autonomous formations already have much smaller overall dimensions and, accordingly, the least large-scale tasks. Such VOCs are designed to serve waste disposal facilities for household and industrial waste of significantly smaller volumes, parameters and values.

These objects, as a rule, are sanatoriums, boarding houses, car washes, small industrial enterprises, hotels, children's camps, small villages or groups of houses that are located away from the central city sewerage system and do not have the possibility of connecting to these highways.

Such VOCs look smaller in scale than VOCs of city networks, and therefore are called somewhat differently:

These installations must necessarily be supplemented with filtration structures or devices so that the purified water reaches the highest purification rating of 98 to 100%. These VOCs can exist on their own only for an incomplete wastewater treatment cycle.

Septic tanks

A septic tank is a sewerage structure that consists of one container divided into chambers, or several containers that represent chambers for the operation of the septic tank.

Such structures are small-sized and have in their internal structure all the necessary devices for purifying and settling wastewater.

Today, the sewerage equipment market offers a wide range of wastewater treatment products made from different types of plastic: low-density polyethylene (HDPE) and polypropylene (PP).

These materials are very lightweight, and therefore installations made from them are easy to install. Also, plastic very well withstands all kinds of temperature changes, mechanical loads, pressure and exposure to the aggressive environment of sewage fermentation inside the septic tank.

Septic tanks are not considered the final points for complete wastewater treatment; filtration fields must also be added to them, which ensure soil purification by almost 100%.

Full-type treatment plants usually include deep biological treatment stations, which, as a rule, do not require additional installations of filtration fields or wells, purifying wastewater by 98-100%.

Aero tanks

Aero tanks are special open rectangular tanks where wastewater is purified and settled.

Aero tanks also have a long shape and resemble small channels through which wastewater flows, mixing with activated sludge using air flows, which processes the wastewater.

Also, aeration tanks can trap fatty inclusions in drains, oil products and other substances that float to the surface.

Such devices are not built on their own, but are always included as part of entire city sewerage structures.

Devices such as aeration tanks can often be found in treatment facilities for autonomous sewer systems such as septic tanks or deep treatment stations. Only these aeration tanks have a very miniature appearance and are built inside the VOC chambers.

Biofilters

Biofilters - as well as aeration tanks - are part of the entire VOC of the city sewerage system, and can also be used for septic tanks in a reduced design.

Biofilters provide the deepest with the help of colonies, which are placed in special devices, where they are provided with a normal environment for life.

• mechanical;
• biological;
• physico-chemical;
• post-treatment.

All wastewater goes through certain stages of purification. First, the sewer system is cleared of solid suspended particles that settle to the bottom, then fats, oil products and other fat-containing inclusions are captured in the wastewater in the form of food waste.

In urban VOCs, the first stage is always mechanical, where insoluble or poorly soluble particles that are heavier than the water mass are captured and settled mechanically.

If the VOC serves a storm sewer or industrial sewer, then at the first stage the wastewater will be cleared of sand, stones, polyethylene, glass, fibrous particles and other types of debris.

Mechanical wastewater treatment

Mechanical treatment of sewage water is designed to treat exclusively “black” wastewater - the so-called primary sewage, household or industrial wastewater that enters the first compartment of the sewage treatment plant.

The first stage of delaying and catching debris allows it not only to accumulate in tanks through special grids, but also to accumulate in tanks, baskets and containers.

After rags, polyethylene and other garbage accumulate in baskets, it is sent to a booker, from where it is transported to special landfills or to workshops equipped with crushers that finely crush the garbage.

After crushing, the waste can go through the following stages of dry cleaning. Heavy stones, glass, and sand are deposited at the bottom of tanks, which are called sand traps.

Subsequently, the suspensions are transported through augers or hydraulic elevators to workshops, where stones are removed, and the sand is cleaned and used for construction or other work.

Photo: mechanical treatment of sewage water

But the water, purified from large fractions of debris, flows into another compartment, where the next stage of mechanical processing takes place - purification from dense substances such as petroleum products and oils.

This is where devices such as grease traps or grease separators, oil traps and flotators come into play.

Due to the lightness of fats and petroleum products, these suspensions float to the surface, are directed by air currents into special containers, where they accumulate, forming a crust, and then are easily removed using the same mechanical method.

Photo: settling tanks for grease collection

Settlers for grease collection are used in different designs and parameters. These can be large-scale horizontal rectangular structures made of reinforced concrete or brick.

Or there may be round, cylindrical devices in the form of wells attached to receiving tanks.

It is these wells that are most convenient to use for fat collection because in such wells fat deposits accumulate best and rise upward, forming a crust, from where they are then removed.

These wells are cone-shaped containers with collection gutters arranged along the periphery, through which oil products and fatty inclusions flow into the container.

Biological wastewater treatment

Water that has already been purified from heavy wastewater is called “grey” wastewater. This gray waste must now undergo biological treatment with colonies of bacteria that can process the sewer liquid to such an extent that it turns into sludge and water.

Important! The sludge mass should settle and settle to the bottom of the tanks, and the clarified water should flow into the next chamber for further purification.

Bacteria begin to work precisely when the water no longer contains suspended insoluble particles and consists of those substances that do not float or settle, and therefore they are most easily removed from the water by treating it with an organic medium.

Photo: bacterial colonies

Such installations look like septic tanks, without any additional structures or devices installed inside or near them, such as round artificial ponds or open tanks with activated sludge, which contains the necessary microorganisms that ensure the natural course of wastewater purification.

Here, wastewater purification does not occur completely, and therefore the degree of purification after biological ponds is not high. In addition, in winter, purification of such ponds with the help of bacteria is impossible, so in winter such devices as aeration tanks or biofilters are used.

In aeration tanks and biofilters, aeration and recirculation of activated sludge occurs forcibly, which means the presence of various mechanisms powered by electricity during operation.

Thanks to aeration tanks, which constantly drive air currents into wastewater, the wastewater is mixed with activated sludge, which contains aerobic bacteria.

These microorganisms are dangerous to human health, but are very useful in wastewater treatment. They are activated by the supply of free oxygen molecules, which is why aeration tanks are so important in wastewater treatment plants at the stage of biological treatment.

The organic environment present in activated sludge is very demanding on wastewater, which has the following undesirable inclusions or contents:

• the mandatory presence of nutrients for bacteria in the wastewater - the water must be dirty and contain organic waste, and the aggressive chemical environment of the wastewater can kill life-giving bacteria of some types;
• Undesirable types of contaminants should be as absent as possible from the wastewater that needs to be treated by bacteria - such contaminants may include chlorine-containing, alkaline, acidic and other aggressive chemicals;
• the wastewater temperature necessary for life must be maintained - at temperatures below +5˚С and above +60˚С, many types of bacteria die;
• For aerobic bacteria, an optimal oxygen concentration is required, and for anaerobic bacteria, an almost complete absence of oxygen is required.

Local biofilters necessarily contain a biosubstrate of bacterial colonies that are located in the filter itself. Aerotanks do not contain biosubstrates; there bacteria move freely with air flows through the wastewater, treating them.

Biological wastewater treatment takes place in the same way as mechanical treatment, in several stages, during which there is a gradual purification of substances contained in water, such as:

• BOD (biological oxygen demand);
• COD (chemical oxygen demand);
• ammonium nitrogen;
• nitrates;
• nitrites;
• and other harmful substances that are present in the treated wastewater.

The most significant advantage of aeration tanks and biofilters compared to artificial settling ponds or septic tanks is their high performance in terms of wastewater treatment to the highest degree - 100%.

It is in such structures that it is possible to create the necessary conditions for the development of colonies of life-giving bacteria that process sewer water.

In addition, in biofilters, as in aeration tanks, wastewater can be easily processed in winter, but in ponds such treatment is impossible due to low temperatures. But the advantage of septic tanks or treatment ponds is the unpretentiousness of their designs and the comparative low cost of installation and its operation as well.

Physico-chemical treatment of wastewater

After biological treatment, significantly clarified water enters such facilities, where it is directly treated with all kinds of chemical compounds.

This purification step is necessary because after treatment with bacteria, there may still be small dissolved particles in the water that are not to the taste of the bacteria, so to speak. After all, not all inclusions in wastewater are suitable for processing by bacteria.

These substances can be: residues of petroleum products, residues of food waste decay products, pieces of undissolved particles of any material and other small inclusions.

Photo: physical and chemical wastewater treatment

The principle of operation for treating wastewater from such facilities is as follows: wastewater is actively treated with chemical reagents that are capable of attracting any smallest particles of any kind contained in the water.

Such reagents are coagulants or flocculants, which help remove and extract the smallest particles of dirt and debris from water. Molecules of reagents tend to stick together and attract molecules of other soluble and insoluble particles in water.

After they have attracted the particles to themselves, they begin to stick together, forming lumps, and in some cases flakes, depending on what reagent was used and what particles needed to be attracted. The resulting lumps and flakes successfully settle to the bottom of the VOC container.

Chemical treatment of wastewater usually occurs in two stages:

• mixing with reagents;
• flocculation.

When mixed with reagents, special pH conditions are created, as well as the required water hardness, so that the effect of particle capture and the formation of lumps or flakes by coagulants or flocculants is most effective.

Mixing of reagents with water occurs either using hydraulic mechanisms specially arranged in these tanks, or using mechanical forces using special devices.

Water mixed with the reagents flows into the lump formation and flocculation chamber, where the resulting lumps and flakes settle to the bottom under the influence of a gravitational field (the process is therefore called physicochemical).

The water is thus further clarified and purified and enters the next tanks to undergo a full purification cycle. Accumulated flakes and lumps from the chamber are removed and disposed of.

Wastewater treatment

At the last stage of wastewater treatment, clarified or 95-98% purified water undergoes final treatment through special sorbing filters, reaching a 100% degree of purification after treatment.

Such water can be supplied to water intakes, from where it can be taken for use for economic and technical needs.

At the post-treatment stage, water goes through:

• disinfection – removal of bacterial residues that are harmful to human health using chlorine or UV rays;
• disinfection – removal of chemicals in the form of reagent residues using chlorine or UV rays;
• microfiltration – cleaning from small residues of reagents or bacteria;
• filtration through sorption filters - water is purified by separating residues of harmful particles or molecules from it by sorption substances.

Purified and neutralized water fully complies with all sanitary and environmental standards and can be freely used in technical and economic work, except for the food industry and the use of such water as drinking water (it is not suitable for drinking).

Also, such water can be safely discharged into reservoirs, ponds or rivers - it is completely harmless to the natural environment.

Constructions for summer cottages

Autonomous sewer systems also include portable VOC installations, which can freely serve not just individual homes and families, but entire villages, sanatoriums, boarding houses, car washes, restaurants, cafes or hotels, depending on the volume, productivity and parameters of a particular model autonomous VOC.

Such treatment facilities can also be perfect for a summer residence. These include popular local treatment facilities: UNILOS, Lokos, Bioksi, Topol and a host of other manufacturers of deep biological treatment sewer stations.

Such stations are most often manufactured and installed in a vertical position; some models can be installed in any type of soil, clean drains and maintain an autonomous sewage system in a country house no worse than a city one.

Photo: Topas wastewater treatment plant

Such VOCs for autonomous sewers are designed, manufactured and operate according to the operating principle of urban structures, but with the only difference that the cameras and devices have minimal dimensions.

Just like at large stations, most portable VOCs can capture sand, oil products and treat wastewater with biomaterial. Most of these plants treat wastewater up to 98%, which is a very high level.

These stations are easy to install, maintain, and are not subject to corrosion, since their cases are made of durable plastic. The units work perfectly in any weather conditions and do not create any annoying noise or unpleasant odor.

When servicing such local treatment stations, which are installed in autonomous sewer systems for summer cottages, you should pay attention to the following operating points:

• there is a good opportunity to carry out regular inspections of internal devices and the degree of water purification thanks to special timers and control devices;
• aeration devices that contain membranes last more than 10 years, and therefore there is a high guarantee for uninterrupted, excellent wastewater treatment for 10 years;
• switching valves provide the highest degree of wastewater treatment;
• thanks to the presence of such a device as an airlift, the biomass is not destroyed and is not completely pumped, but remains in the settling chamber, which allows the unlimited use of activated sludge, without adding any additional biological products to it, for wastewater treatment;
• automated systems allow the station to turn on when wastewater enters the receiving chamber in a certain volume, and the operating mode can be automatically adjusted depending on how much wastewater enters the chamber;
• an aerobic stabilizer allows you to remove excess sludge, which significantly improves the operation of the entire system;
• activated sludge can be freely used as fertilizer for garden and vegetable crops or decomposition in compost;
• servicing the stations with a sewer truck is not required, because the pumped out sludge can be used as fertilizer or simply freely supplied to ravines, reservoirs or soil trenches without disturbing the ecosystem;
• built-in pumping equipment in the stations allows them to be used without the use of additional pumping equipment;
• Chemicals, poisons and other aggressive substances must not be discharged into such sewers;
• filters of a washing vacuum cleaner should not be washed into such a sewer;
• If possible, the discharge of pet hair, threads, hair and other fibrous debris into such sewers should be limited;
• It is prohibited to discharge polyethylene, glass, plastic or any other insoluble substances into sewers with deep biological treatment stations;
• Detergents containing manganese (washing filters for purifying drinking water), salts, chlorine or acid should be used as little as possible; instead, biological detergents should be used more often.

It is clear that such stations seem capricious in operation, but these are the conditions and rules for their use and maintenance, and therefore if you follow these recommendations from the manufacturer, then such VOCs for dachas will serve for many decades without creating any additional hassle, breakdowns or repairs.

VOC for industrial plants

The treatment of wastewater from industrial enterprises is somewhat different from the treatment of wastewater coming from populated areas. The differences consist, by and large, in the aggressiveness and harshness of the reagents and activated sludge used.

After all, industrial liquid waste differs from household waste in the degree of contamination and composition of the wastewater.

Such VOCs, which serve industrial enterprises, contain in their design and structure several lines that provide treatment of industrial wastewater:

• three parallel lines for physical and chemical treatment of industrial wastewater;
• special aeration tank greenhouse with eichornia and activated sludge;
• line-unit for UV disinfection of wastewater;
• biopond for post-treatment of industrial wastewater.

These VOCs ensure the treatment of sewage from industrial enterprises in various fields and areas of production:

• meat processing plants;
• oil mills and vegetable oil factories;
• poultry farms;
• fish canning factories;
• breweries;
• car washes;
• energy facilities;
• galvanizing workshops;
• glass factories;
• and other industrial enterprises.

Primary industrial wastewater enters directly into a storage tank and is purified through drum biofilters, freeing it from large fractions of debris.

From an accumulating type tank, the purified wastewater sequentially enters a special settling tank, where the wastewater is subjected to flotation and oxidation using special reagents - coagulants and flocculants, binding and forming lumps or flakes, which gradually settle to the bottom of the tank.

After the flotation settling tank, the settled water flows into a biofilter, and then into aeration greenhouses, where the water continues to be purified using activated sludge. And after these stages, the clarified water enters the biopond, where it undergoes further purification.

Photo: aeration greenhouses

Each stage of industrial wastewater treatment takes place in a separate building, a separate workshop, which is very convenient for separating and controlling the entire treatment process.

Most local treatment facilities also use the UV (ultraviolet) method of wastewater disinfection.

Almost all VOCs for industrial wastewater treatment have the same treatment schemes for all types of sewage wastewater.

Stormwater treatment plants

Cleaning storm drains is also not an easy task. At first glance, it may seem that the composition of storm water is not so heavy and concentrated, and therefore it is easier to purify such wastewater.

However, in fact, wastewater contains quite a lot of natural impurities, as well as chemical inclusions, if various surfaces containing chemical coatings or compositions come across the path of the storm sewer.

Important! And if we also take into account rainwater, which due to its composition can also destroy any ceilings, if rainwater stagnates on them, it can create waterlogging in lawns or any other local areas, as well as wash away the foundation in the rainy seasons, if not divert these flows away from the house.

All VOCs for storm sewers have a fairly high productivity and can purify wastewater up to 98%, which is the highest rating for wastewater treatment adopted by SNiP 2.04.03-85 “Sewerage.

External networks and structures”, as well as regulatory documents such as “Recommendations for the design of systems for collecting, draining and purifying surface runoff from residential areas, enterprise sites and determining the conditions for its release into water bodies” (FSUE “NII VODGEO”).

Almost all manufacturers of industrial or household VOCs for stormwater treatment adhere to regulatory documentation, and therefore their installations and systems purify stormwater quite effectively.

Photo: contents of treated wastewater

Important! All treatment facilities for storm sewers must have sand traps and oil traps. Sand, petroleum products and other abrasive and oily substances are often found in stormwater runoff and therefore should be treated with VOCs first.

Sewage facilities also include settling tanks, where sediment is successfully formed not only from solid particles such as stones, glass, tree branches and other debris, but also from small particles that are washed in by the movement of melt and storm water flows.

The last stage of stormwater purification is also settling and disinfecting it using UV rays. Treated wastewater can be freely supplied to reservoirs, rivers or fields.

In addition to domestic storm drainage, there is also industrial storm drainage. Such VOCs purify not only rain or melt water runoff, but also others.

For example, these treatment facilities can serve the following facilities:

• car washes;
• industrial enterprises;
• factory areas;
• parking areas and parking lots;
• territories of entertainment centers;
• territories of business centers;
• territories of complexes for vacationers and tourists;
• territories of settlements and private houses, including.

Photo: industrial storm drainage

Storm sewer systems consist of the following elements:

• distribution well;
• sand trap;
• oil catcher or oil-gasoline separator;
• sorbing filter;
• control well for sampling purified water.

All these structures can be assembled and installed either in the form of separate containers, collected into a single sewer system, or located inside one large container, which is called a deep stormwater treatment station.

During installation, all conditions must always be met that will not only preserve the structure from all kinds of harmful influences, but will also provide an excellent opportunity for it to work for the longest possible time without failures.

Prices

The cost of constructing large-scale urban VOCs, of course, significantly exceeds the cost of autonomous VOCs. It is clear that such buildings are not sold ready-made on the wide market, but are ordered from construction companies.

But household VOCs, such as, for example, local treatment plants Tver, Yubas, Eurobion, Unilos, Topas and other systems intended for installation in autonomous sewer systems, are presented on the sewerage equipment market in a wide range:

VOC name	Material of manufacture	Maximum number of people served	Length	Width	Height	price, rub.
Tver-0.75P	Polypropylene	3	2250	850	1670	69900
Tver-1P	Polypropylene	5	2500	1100	1670	87900
Tver-2P	Polypropylene	10	4000	1300	1670	131900
Tver-3P	Polypropylene	15	4000	1600	1670	151900
Tver-6P	Polypropylene	22-30	4000	1600	1670	299800
Tver-16	Steel	50-80	8700	D=1900	1000	619300
Tver-100	Steel	300-500	1160	D=2400	2000	3086000
Tver-180	Steel	600-900	1040	D=2400	2000	5390000
Tver-300	Steel	1000-1500	1160	D=2400	6000	8790000
Tver-500	Steel	2000-2500	8300	D=2400	5000	14396000

All local treatment facilities have their own differences and purposes. There are VOCs that serve entire cities, towns, and neighborhoods in megacities, and there are those that serve not centralized city sewers, but autonomous sewer networks.

Almost all types of sewerage facilities operate according to the same scheme, achieving wastewater treatment to a high degree.

In the modern world, a variety of technologies are used that can significantly improve people's lives. One of such systems is various local treatment facilities. Such devices and units are designed for wastewater treatment. They are simply irreplaceable for country houses. In this article we will talk about such a system as a local sewerage system and what devices are used in it.

Very often from utility workers you can hear such an abbreviation as VOC. To put it simply, such devices are called local treatment plants, and they form the basis of an autonomous sewage system.

Note! Classic treatment plants operate on the principle of reducing the flow rate of wastewater. As a result of the drop in speed, solid particles settle to the bottom, and the remaining impurities are subsequently removed using post-treatment devices.

In order for classic treatment facilities to cope with their task, it is necessary to correctly select the volume of containers into which the wastewater will flow. According to certain calculations carried out by experts, one person consumes up to 200 liters of water per day. This means that the amount of waste “generated” is the same.

For a classic treatment system, it is necessary for the wastewater to settle for several days. Therefore, the containers must be large, and this is very difficult for private houses. This is why autonomous sewer systems do not use the classical method of wastewater treatment.

VOCs are intended for treating wastewater from private houses, summer cottages or small villages. Where it is not possible to connect to a centralized sewer system, country property owners build autonomous devices. These include the following structures:

• septic tanks;
• aeration tanks;
• biofilters.

Note! Each of the listed structures has its own characteristics and area of ​​most effective use. But in addition to the VOCs themselves, filtering devices must be included in the autonomous sewage system. Only in this case can we approach the level of wastewater treatment of 98–100%.

Very often, when talking about an autonomous sewage system, owners of country houses remember such treatment facilities as septic tanks. Such devices are a plastic (sometimes other materials are also found, especially if the septic tank was made independently) container or several containers.

The choice of plastic as a material for tanks is determined by its positive characteristics:

• the lightness of the resulting structure, which greatly facilitates transportation and installation;
• easily tolerates exposure to aggressive environments;
• does not corrode;
• has sufficient strength.

Inside each tank there are several sections, each of which performs its own task. Some sections play the role of a settling tank, in others wastewater is purified using colonies of microorganisms, in others there is filtration, etc.

Septic tanks are most often found in on-site home treatment facilities. This popularity is explained by ease of operation and long service life (according to manufacturers, up to 50 years). Moreover, such devices can be either completely autonomous or dependent on electricity supplies.

Note! In most cases, to increase the degree of purification, septic tanks are additionally equipped with aeration or filtration fields. But there are models called deep biological treatment stations, which are capable of independently purifying wastewater to almost 100%.

Such devices are most often found in large wastewater treatment plants that process wastewater from large enterprises or populated areas. They are large containers where water is mixed with activated sludge using oxygen. If we are talking about autonomous systems of private houses, then aeration tanks have more modest sizes and are most often installed in septic tanks or other VOCs.

Note! Quite often, aeration tanks are equipped with special catchers. Such additional equipment helps to clean wastewater from oil products, grease and other floating substances. Such catchers are usually equipped with aeration tanks operating at large wastewater treatment plants.

In addition to aeration tanks and septic tanks, biofilters can be used in local treatment systems. Most often, they are part of VOCs. Biofilters are rarely used on their own. Such devices purify wastewater using colonies of microorganisms.

Note! Bacteria in an aquatic environment saturated with oxygen or without access to air decompose all sewage in wastewater. As a result, the output is water containing only simple substances that do not harm the environment.

Once in the local treatment plant, sewage effluents go through several stages in succession. As a result of each of them, wastewater is purified from certain pollutants.

Let's look at these steps based on the most common VOC that is most often used in autonomous sewer systems - a septic tank. Once in such a device, wastewater passes through:

• Mechanical cleaning. At this stage, the wastewater is freed from solid and large fractions. This most often occurs in tanks called a sump. Here heavy and solid fractions precipitate. After a certain amount of sewage has accumulated, it is pumped out using a fecal pump or a sewer truck.
• Biological treatment. This stage can be considered the most important. In special containers, cleaning occurs using colonies of microorganisms. This process can occur without access to atmospheric oxygen. In this case, the septic tank does not need to be connected to the electrical grid. If microorganisms living in an oxygen environment take part in the work, then compressors are used to supply air from the atmosphere. In this case, the septic tank is considered volatile.
• Additional treatment. After passing through several chambers (settling tank and biological treatment sections), sewage is considered not completely purified. To remove residual sewage from them, it is necessary to install a post-treatment system. As a rule, aeration or filtration fields are used as such. In the first case, wastewater is poured onto special open fields of quite large size, where the work of microorganisms continues, but in a natural environment. To save space, a suburban autonomous cleaning system can be equipped with filter devices. In this case, the effluent from the septic tank ends up in ditches or pits filled with crushed stone or other solid fillers with large fractions.

Note! If you use biological treatment stations on your site, their operating principle is similar to a septic tank. The only significant difference is the absence of aeration or filtration fields.

Since septic tanks are most often used in autonomous treatment systems for private homes, it is worth familiarizing yourself with the recommendations for their operation:

1. Treatment plants equipped with devices such as airlifts operate more efficiently. With their help, activated sludge is not “thrown out” of the septic tank, but remains inside. As a result, cleaning occurs more efficiently and does not require additional “population” of colonies of microorganisms.
2. The amount of activated sludge may be excessive. To prevent the septic tank from overfilling, it is better that it be equipped with an aerobic stabilizer.
3. Activated sludge itself is an excellent fertilizer for vegetable and garden plants. Therefore, you can save a lot by not calling a sewer truck, but by pumping it yourself directly to the beds.
4. For cleaning to be effective, microorganisms must not be allowed to die. To prevent this from happening, try not to “discharge” various poisons, chemicals and aggressive substances into the autonomous sewage system. It is also not recommended to use detergents containing chlorine. This element is poisonous to most types of microorganisms used in septic tanks. In addition, you should not flush the contents of filters from washing vacuum cleaners down the toilet.
5. Since solid contaminants accumulate in the septic tank, they should not be allowed to enter the sewer system. After all, this will lead to an increase in your operating costs.
6. Perform a visual inspection of the septic tank periodically. It is worth remembering that although such structures have a fairly simple structure, they can sometimes break down.

Video

In the provided video materials, you can get more information about the local sewerage system:

The importance of treatment systems is undeniable. No building that is used by man can do without them. New manufacturing enterprises, gas stations, bars and restaurants, other establishments in the service sector, apartment buildings or country houses are constantly emerging, and the problem of high-quality wastewater treatment remains relevant. To solve this problem, enterprises, local authorities, and residential property owners are building local treatment systems of various types.

VOC concept

Devices, structures, complexes of structures with various utilities and various combined systems, the main purpose of which is the complete or ultra-deep purification of household, industrial, rain and other sewage wastewater, are called local treatment facilities (WTP).

Many people equate VOCs with autonomous sewers - this is incorrect, since autonomous sewers are one of the types of VOCs that function independently and exist separately from the central sewer main.

Interesting to know. The most important task that such structures, structures and their complexes must solve is the purification of wastewater to a level that is described in the legislative rules and regulations of the relevant services, guaranteeing the absolute safety of the surrounding flora and fauna, health and life of people.

Types of VOCs

Local sewage treatment facilities can be divided into the following types by location:

1. Treatment systems that are part of the municipal central sewer system, which, after processing wastewater, send it to the city sewer network;
2. Treatment systems that serve buildings or complexes of buildings separately from the central sewer main, since they are located at a decent distance from it or without the possibility of connecting to it (autonomous sewerage).

VOC of centralized sewerage

The first group mainly consists of large-scale systems that include a number of large treatment facilities that form an automatic complex for processing large volumes of industrial wastewater from factories, industrial production, factories and domestic wastewater from cities, towns, and other populated areas.

Such sewer systems are usually built outside the city line. The territory allocated for their construction and operation is a sanitary zone where it is prohibited to live and conduct various recreational activities.

They are maintained by specially trained personnel, and they operate using special devices and equipment, control panels and automation systems.

Independent VOCs

Autonomous VOCs have smaller dimensions. They are installed to purify industrial wastewater from small industrial organizations and factories, as well as wastewater from human economic activities. They have a simpler design and cleaning technology with lower power and throughput.

Often, local autonomous treatment systems serve service enterprises, small villages and individual residential buildings located far from the municipal treatment network.

How does VOC work?

The overwhelming number of local treatment facilities operate using a multi-level method of wastewater treatment, which consists in their passage through the following stages:

• mechanical (rough);
• bacterial (biological);
• chemical-physical.

Rough cleansing

Domestic fecal water, as a result of mechanical purification, is passed through various filter systems that retain large inclusions in it. The stage in which the wastewater passes through the first filter system is called rough treatment. After this stage, the wastewater passes through the next set of filters, designed to remove smaller inclusions from the wastewater. Upon completion of passage through the filters, the water enters specialized storage tanks, where the process of clarification occurs.

Chemical cleaning

Since wastewater is affected by various chemical reagents, inorganic and organic compounds, which have a detrimental effect on the environment, before discharging such water into a reservoir or river, it is necessary to carry out a process of chemical neutralization. This process is based on oxidation-reduction reactions. For example, if you want to get rid of contaminants in water caused by alkaline solutions, it is necessary to treat the liquid with various acids, and vice versa.

Bacterial cleansing

This stage consists of cleaning wastewater from various organic contaminants using special bacteria, which, by processing such contaminants, start the process of their decomposition with further removal from VOCs. This stage of purification can take place in an oxygen-free or oxygen environment, against which a distinction is made between anaerobic and aerobic purification.

Types of autonomous treatment systems

Autonomous local treatment systems include the following types of structures:

• septic tanks with settling tanks;
• biofilters;
• Aerotanks.

These systems differ from each other in their design features and the method of wastewater treatment.

Important! Any of the above-mentioned structures must be equipped with filtering installations or structures, since on their own they will not be able to organize a full processing cycle, in which the water will be purified by 97-100%.

Septic tanks

Structures for organizing sewerage, consisting of storage tanks divided into chambers for cleaning and sedimentation of wastewater inclusions, are called septic tanks. They can include several storage tanks in their design. They are most popular for organizing a sewer system in summer cottages and household plots, as they have a low cost and a high level of practicality.

Septic tanks are small in size and contain all the necessary equipment for organizing the treatment of sewage water.

Such septic tanks are produced on an industrial scale, mainly from high-strength plastic. This material is lightweight, which makes installation of the septic tank quick and easy. Such systems perfectly withstand sudden temperature fluctuations, exposure to various aggressive environments, stress and mechanical loads.

The construction of a septic tank can be made of concrete and other materials.

Note! Septic tanks are not capable of treating wastewater 100%, as they are VOCs of an incomplete cycle. It is imperative to create special filter fields together with them, which contributes to almost complete soil purification.

On the market of local treatment systems you can find ultra-deep cleaning stations, which are a kind of septic tank, where all kinds of filtering devices and other cleaning means are already installed. Such devices have compact dimensions and provide almost one hundred percent purification of sewage water.

Aerotanks

Specialized open storage tanks in the shape of a rectangle, where the filtration process and sedimentation of abrasive fractions of wastewater are carried out, are called aeration tanks.

Aerotanks have an elongated shape, reminiscent of water channels through which household and fecal fluid moves, mixing with the help of air pressure with activated sludge (a community of protozoa), which is responsible for their processing.

Various substances that appear on the surface, for example, petroleum products, fatty inclusions, can also be removed in aeration tanks.

These structures do not exist separately, but are part of a complex of municipal sewerage systems or, in a reduced form, are built into a septic tank with sedimentation tanks and ultra-deep treatment stations.

Biological treatment design

Biofilters are considered special containers or structures that serve for deep purification of wastewater using colonies of certain bacteria released into them. Just like in aeration tanks, they are part of complexes of municipal sewer systems or, in a smaller and simplified version, are built into septic tanks.

In addition to microorganisms, filter materials are placed in biofilters that provide mechanical treatment of wastewater, for example, expanded clay.

VOCs for industrial enterprises

Local treatment facilities for industrial enterprises operate according to a progressive and more complex structure for processing wastewater with more complex contaminants.

Treatment systems serving large or complex technological enterprises contain in their structure:

• Mechanical cleaning line. The waste liquid enters a storage tank, from which it is distributed to biofilters, getting rid of large inclusions;
• Simultaneously functioning processing of industrial wastewater by chemical method. Having gotten rid of large fractions, the wastewater enters various settling tanks containing certain chemical reagents and solvents, which bind with organic and inorganic water pollutants, forming feathers or lumps that settle at the bottom of the tank;
• Specialized greenhouses with aeration tanks that contain activated sludge and water hyacinth, which removes organic fractions from water;
• Biological ponds for post-treatment of wastewater, in which the last stage of working with fractions takes place through the influence of special microorganisms on them;
• Disinfecting station for sewage water treatment using ultraviolet radiation.

Typically, each stage of industrial wastewater treatment is carried out in a separate building or room, which makes it possible to avoid the release of polluting compounds or substances from these sewage effluents into the atmosphere, as well as to comfortably exercise control over the entire technological process.

VOCs according to this structure ensure the processing of sewer lines at the following enterprises:

• poultry farms;
• meat processing plants;
• factories for the production of glass and other glass products;
• canneries;
• car washes;
• factories of fat-containing products and vegetable oils;
• and other industrial enterprises.

VOCs for rainwater runoff

Systems for processing storm water runoff have their own characteristics in terms of structure and treatment methods, which is due to the presence in their composition of a significant content of suspended matter of natural origin, chemical compounds and large particles.

These VOCs can function successfully to treat stormwater from the following facilities:

• car washes;
• factories;
• territories of industrial enterprises;
• large parking lots and parking lots;
• adjacent areas to business centers and retail facilities;
• personal plot.

So a standard storm sewer system should contain the following elements:

• settling tank;
• catcher for sand and other abrasive particles;
• catcher for oil-containing substances (oil catcher);
• sorbing filter;
• UV disinfection system;
• control tank for testing purified liquid.

VOCs for storm sewer systems have a high level of wastewater purification (up to 98%) and productivity, since they must be prepared to process large volumes of liquid, for example, during prolonged rains.

The design of such sewer systems contains sedimentation tanks, where wastewater is separated from large fractions such as branches, street litter, glass, cobblestones and other particles washed with water from melting snow or rain.

VOCs for storm drainage must contain sand and oil-containing substance traps in their system, since storm drains contain a large amount of abrasive substances and petroleum products emitted by cars and gas stations.

The final stage of purification of such wastewater is its disinfection using ultraviolet rays, after which the purified liquid can be sent to natural reservoirs.

Local treatment facilities for sewerage of any type provide those technological solutions that reliably ensure high-quality wastewater processing without having a negative impact on the environment, making human life easier and more comfortable.

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