Human life is inextricably linked with water. Therefore, in the construction of housing, one of the first concerns is the construction of a water pipe. But if water is supplied to the house, then you need to take care of the disposal of wastewater. In order to recycle used water and to keep the soil and water clean, wastewater treatment systems must be used. Let's consider what installations can be used for sewerage equipment in a private house.

Today, few people are satisfied with the prospect of living in a house devoid of amenities, even if it is just a dacha. Most owners strive to make their home as comfortable as possible: organize heating, conduct water into the house.

But if there is a water supply system, then a sewerage system is also needed - a system for diverting and processing wastewater. Since far from all suburban settlements have a centralized system for collecting and processing domestic wastewater, a local wastewater treatment system is being built.

Wastewater treatment methods

To clean domestic sewage, as a rule, the following cleaning methods are used:

• Mechanical - settling, filtering.
• Biological - processing of wastewater by microorganisms.

In nature, there are two types of bacteria that can effectively clean drains:

• Anaerobes are microorganisms that carry out their vital activity without oxygen.
• Aerobes are bacteria that do not "work" in an oxygen-free environment.

As practice shows, it is possible to achieve the greatest effect in wastewater treatment if a combination of several treatment methods is used. The modern treatment system provides for the initial settling of wastewater, and then their biological treatment using anaerobes and aerobes.

Anaerobic septic tanks

A septic tank is an installation in which drains go through several phased stages of treatment. The principle of operation of a septic tank is to settle wastewater and process organic matter by anaerobic bacteria. To achieve the best quality of cleaning, septic tanks are made multi-chamber. The main part of the solid waste settles in the first chamber, and pre-purified water flows into the subsequent chambers.

Organic inclusions, which make up most of the pollution of domestic sewage, decompose under the action of anaerobic bacteria. Organics decompose into simple components - methane and water, and insoluble residues settle to the bottom of the chambers.

Treatment of wastewater with aerobic bacteria begins after it leaves the septic tank and enters the aeration fields - devices necessary for post-treatment of wastewater. On aeration fields, wastewater is additionally filtered, passing through a filter made of sand and gravel. Thus, after going through all the stages, the water is purified by almost 100% and does not harm the environment.

Cleaning steps in an anaerobic septic tank

• Stage one. It is carried out in the primary sump. There is a process that is commonly called clarification of drains. In the first chamber, the contaminated water is separated by specific gravity. Particles that have a heavy weight settle to the bottom, inclusions that are lighter than water rise to the top. In the center of the primary clarifier, where the overflow pipe to the second chamber is located, clarified effluents are collected. Settling continues in the second chamber, only here the sedimentation of smaller inclusions, which are in the liquid in suspension, is already taking place.

Advice! Septic tanks are built in such a way that drains from chamber to chamber flow slowly. Only at a low speed of movement is it possible to ensure high-quality sedimentation.

• The second stage is biological. Organic matter that has settled to the bottom undergoes biological processing by anaerobic bacteria. During the fermentation of the sediment, heat is released, so the temperature in the septic tank is always elevated. This circumstance allows the use of septic tanks not only in summer, but also in winter.

• The last stage of cleaning takes place on the filtration fields. The effluents clarified in the septic tank are supplied here through pipes. Holes are made in the pipes through which water seeps into the soil filter. Passing through a layer of sand and gravel, the water is filtered. In addition, it is additionally cleansed with the help of aerobes that live in the soil.

Aerobic type septic tank

In addition to traditional septic tanks, modern systems of biological wastewater treatment - VOCs, additionally equipped with aerators, are widely used today. In such stations, wastewater is alternately processed by anaerobic and aerobic bacteria, as a result, at the outlet of the treatment plant, the water is 98% purified, so there is no need to build filtration fields.

Water purified in VOCs can be discharged onto the ground or into the nearest body of water without harm to the environment. If necessary, water can be directed to a storage well for domestic use, such as lawn or garden irrigation.

Stages of wastewater treatment in aerobic septic tanks

• The first stage is upholding. Just like in conventional septic tanks, VOC uses such a simple but reliable mechanical cleaning method.
• The second stage is the processing of the sludge by anaerobic bacteria. Organic matter that has fallen in the form of a precipitate is processed by anaerobic bacteria. That is, up to this point, there are no differences in the operation of a simple septic tank and VOCs.
• The third stage is processing with the help of aerobic bacteria. When the aerator is turned on in the chamber, the stage of aerobic cleaning begins. In an environment saturated with oxygen, bacteria efficiently and quickly process most of the organic inclusions.

• Stage four - again upholding. After aerobic treatment of wastewater, water enters the secondary clarifier, where the insoluble sediment - sludge - settles. Purified water enters the outlet, and activated sludge is reused in the purification process. As excess sludge accumulates, it will need to be removed from the sump.

Simple septic tank or VOC?

What kind of wastewater treatment system should be preferred when building a local sewerage system? There is no single answer to this question. When choosing an installation, local conditions will need to be taken into account. Let's conduct a small comparative analysis of septic tanks and VOCs:

• Space required for installation. To install a modern VOC, as a rule, one or two square meters of area is sufficient. If you need to install a septic tank, you will need a large area. The septic tank itself is somewhat larger than the VOC, but the main area will be required for the construction of filtration fields necessary for the post-treatment of wastewater.
• Geological characteristics of the site. If it is decided to install a VOC, then the geological characteristics of the site can only affect the choice of VOC modification. But the arrangement of filtration fields on clay soils is an intractable task.

Advice! If soil water is high on the site, then you should purchase a VOC with forced drainage, that is, equipped with an additional pump.

• Autonomy. If the septic tank is a completely autonomous installation, then the VOC requires power to work.

Advice! If the local sewerage system is equipped with a volatile wastewater treatment plant, then during a power outage it is necessary to reduce the use of water to a minimum. Otherwise, overflow of the chambers may occur, since the pumps pumping wastewater do not work.

• Service. Both a conventional septic tank and VOCs need regular maintenance. The septic tank will have to be cleaned of accumulated sediment about 1-2 times a year using sewage equipment. The cleaning of the sludge collector in the VOC should be carried out more often - about once a quarter, but this work can be easily done on your own.

Advice! When choosing a place to install a septic tank, you need to take into account the need to clean it and leave free passage for the sewer truck.

• Price. A conventional septic tank is cheaper than VOCs. However, it is necessary to take into account the cost of building filtration fields, as well as the fact that filtration fields last no more than 10-12 years, after which they need to be changed.

Design

Having decided on the type of treatment plant, you can begin designing drainage systems for a country house. Most often, the project is made simultaneously with the project of the house. But if a building that has already been put into operation is being improved, then a sewerage project for a private house is drawn up separately.

When designing a wastewater disposal system, local conditions must be taken into account. Therefore, prior to the start of design work, it is recommended to carry out geological exploration, during which the following points will be clarified:

• features of the relief of the site;
• characteristics of the soil, to select the method of water drainage, it is necessary to assess the absorbency of the soil;
• the level of location and seasonal rises of groundwater.

Before the development of a project for a drainage system for a home is started, the following points need to be clarified:

• average daily water consumption in the house;
• frequency of use - year-round or periodically.

After collecting information, you can begin to draw up a project.

Tilt angle

An important point is the angle of inclination of the pipeline. This point is important in the construction of gravity systems. If it is impossible to comply with the required angle of inclination, it is necessary to plan the construction of a pressure system in which wastewater is pumped using a fecal pump.

Many home masters who undertake self-assembly underestimate this point, and meanwhile, errors in both directions reduce the efficiency of the system.

If the angle is not large enough, then the flow will move through the pipeline at a low speed. At the same time, some of the large inclusions will have time to precipitate in the pipes, and this is fraught with the formation of blockages. An angle that is too large will also disrupt the normal movement of the conveyed medium. Water will drain too fast, not having time to carry away heavy inclusions that will linger in the pipes, forming blockages.

The optimal angle of inclination depends on the diameter of the pipe that is used to create the pipeline. The smaller the diameter, the larger the slope angle should be. So, if pipes with a diameter of 50 mm are selected, then a slope of 3 cm per meter should be observed. When using 100 mm pipes, the slope should be 2 cm.

System elements

When creating a project, a diagram of internal and external networks is created. The internal networks include all the elements that are located in the house, these are:

• a riser connected to a fan pipe led to the roof;
• elements of plumbing (sinks, bathtubs, toilets, etc.);
• pipes connecting plumbing elements with a riser.

The boundary separating the internal and external networks is the pipe outlet through the foundation. External networks include:

• a pipeline connecting the output with a treatment plant;
• revision wells for network maintenance;
• cleaning plant.

When constructing a local sewage system, one cannot do without a local treatment plant. Depending on local conditions and the capabilities of the owners, this can be a simple anaerobic type septic tank or a modern local bio-treatment station.

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Sewerage and wastewater treatment in a private country house

Country houses located in country associations, rural areas and even in a number of cottage villages do not always have the ability to connect to a centralized sewer network. The optimal solution to the problem is the use of a local treatment plant - VOC

From the cesspool to the VOC

Modern technologies in the field of engineering equipment are advancing by leaps and bounds, and today many types of domestic wastewater treatment plants have been developed. Recall how the history of private sewerage developed.

First - a cesspool, then its modernized version - a septic tank, and finally installations in which a full cycle of wastewater treatment is carried out. The latter are called differently: stations (systems) for deep biological treatment, wastewater treatment plants (STPs), local treatment facilities (VOCs), etc.

In order not to get confused in these names, which essentially mean the same thing, we will use the abbreviation VOC.

But we will talk about VOCs a little later, and now we will discuss the question: are septic tanks already in the past or not yet?

Since a consumer who is inexperienced in the problems of private sewerage sometimes misinterprets the meaning of this term, it would not be out of place to recall that an industrial septic tank is a large container (most often made of plastic) located in the ground and connected by a supply pipe to the sewer outlet from the house.

The simplest septic tank is essentially a large barrel, more complex models are divided into two or three sections or consist of two or three separate containers. In a septic tank, wastewater does not just accumulate, it is their primary decomposition into heavy ones, gradually settling down, and light ones, floating to the surface. Thanks to this treatment method, which is called mechanical, the wastewater is cleaned by 60%, which is a very low degree of purification, and therefore it is forbidden to dump it on the terrain.

Ten-year-old technologies implied the installation of filtration fields in the area adjacent to the house - drain systems, through which soil post-treatment of wastewater from the septic tank took place. Today, this is an outdated method. However, the septic tank itself cannot be discounted. Sometimes it helps to solve certain problems. For example, if we are not talking about a year-round country house, but about a summer house where the family visits seasonally or periodically. Since the septic tank is suitable for processing a relatively small volume (1 -3 m 3 / s.) of domestic wastewater and fecal matter, it will be necessary to call in a sewage truck from time to time. To reduce the rate of filling the tank, drains can be divided into "gray" (water after washing dishes, bathing, washing) and "black" (receipts from the toilet) and send only "black" to the septic tank.

In any case, for a house of periodic stay, a septic tank will be the most economical solution. Sometimes it has to be set for other reasons. For example, in water protection zones, where it is forbidden to use even VOCs that clean wastewater by 94-98%. Actually, this is all the information that a private developer needs to know about a septic tank in order to make a choice in favor of a septic tank or VOC.

Wastewater disposal options

a) Discharge of purified water by gravity into the existing drainage network
b) Discharge of wastewater to an intermediate well in which a drainage pump is installed
c) Pressure discharge of wastewater into a road ditch
d) Gravity discharge of sewage into a filtering (drainage) well

Principles of operation of aeration VOCs

There are a great many individual sewer installations on the Russian market. Some of them, called differently, are actually almost "twins". And therefore it makes no sense to describe each model separately and compare them. It is much more important for the future user to understand the fundamental constructive difference between systems from each other.

Conventionally, all installations can be divided into two types: aeration and complex. In the first, wastewater treatment occurs due to the work of aerobic bacteria, which use the oxygen contained in the air for their life activity. How does it enter the VOC tank? Aeration (saturation of water with air oxygen) is forced: for this, compressors (pneumatic aeration) or pumps (ejector aeration) connected to the installation are used.

The wastewater treatment method used in such equipment is biological, therefore this type of VOC is also called biological treatment systems (less commonly, bioseptics). Structurally, the device is a container (usually made of polypropylene) with technological hatches, divided by partitions into several sections: septic tank, anaerobic bioreactor, stage I aeration tank - biofilter, sedimentation tank, stage II aeration tank, secondary sedimentation tank - contact tank, pump compartment. The number of camera compartments for different models may be different.

Their common purpose is to sequentially purify domestic wastewater to the parameters specified in the technical data sheet. This is done in the following way. Wastewater is sent to a septic tank, where it is fermented, suspended solids are separated, sand and other insoluble impurities are settled. After that, partially clarified effluents enter the anaerobic bioreactor, where they are treated with anaerobic sludge (community of microorganisms). The process takes place without access to oxygen. Anaerobic bacteria convert organic compounds that are difficult to oxidize into easily oxidizable ones. Then comes the turn of cleaning in the aerotank of the 1st stage with the effect of oxygen (using forced aeration). Here, wastewater is mixed with activated sludge, which absorbs and oxidizes pollution. After that, the wastewater enters the second stage aerotank, where it is further purified (by oxidation and adsorption) with a biofilm of microorganisms formed on a load of artificial "algae" with continuous fine-bubble aeration. Further, in the secondary clarifier, the activated sludge is deposited and returned to the septic tank using an airlift, and the wastewater, purified up to 98%, is discharged to a lower relief place. This is how VOCs of the first type work - aeration ones.

Integrated wastewater treatment plants in a private house

VOCs of the second type are complex installations in which wastewater treatment occurs in three ways: mechanical, biological and chemical-physical (coagulation). Structurally, they differ significantly from aeration plants. Integrated VOCs consist of a vertical sedimentation tank with baffles (septic tank) and a bioreactor located above it. Sediment settling and anaerobic treatment take place in the septic tank. In the bioreactor - aerobic (with oxygen) treatment of already clarified wastewater. Bacteria attach to the biofeed of the reactor, forming an active biofilm. The set of installations includes a precipitating chemical (coagulant) in the form of tablets. It binds phosphorus, significantly reduces its concentration in wastewater and accelerates the process of precipitation. The coagulant is in a plastic container, which is hung on the toilet bowl. With each flush, particles of the substance enter the system along with drains.

What does the consumer need to know?

Aeration VOCs do not allow volley discharge of wastewater (more than 100 l / h). For example, if there are frequent guests in the house, the consumption of wastewater (taking a bath, shower, etc.) increases dramatically, due to which the colony of bacteria that is used for cleaning is partially (or completely) washed out. And consequently, for some time after a volley discharge, the installation will not be able to treat wastewater to the indicators indicated in the passport. A prolonged power outage also negatively affects the operation of systems of the first type, namely, it leads to the partial or complete death of a bacterial colony. True, some manufacturers "forget" to notify the buyer about this. Others convince that this is not a significant drawback of the devices, because you just need to put the bacteria bought in the store for septic tanks into the container, and the installation will begin to function as before. This is true, but reaching the degree of wastewater treatment declared by the manufacturer will occur in this case no earlier than in two to three weeks.

But for complex VOCs, neither a salvo dump nor a power outage threatens negative consequences. The reason for this is in the design differences between the installations of the first and second types. The fact is that in aeration VOCs, aerobic and anaerobic processes occur in one volume, where, due to aeration, there is a constant mixing of activated sludge. In complex VOCs, sludge is deposited in a separate chamber, where it is in a state of relative rest, and since bacteria in such systems live not only in water, but also in a bioreactor, they are not threatened by leaching with abnormal effluents, as well as death due to shutdown electricity. Even with a long interruption in the power supply, the bacteria on the biofilter are alive for three months. The output to the operating mode declared by the manufacturer occurs 4-10 days after the start of the installation.

Household waste (toilet paper, hygiene items) should not enter the aeration installations, as this can lead to blockage of the pumps that ensure the operation of the station. In addition, it is not desirable to drain chemical household detergents there, which worsen the conditions necessary for the vital activity of bacteria. But complex installations are more “loyal” to these factors, mainly due to their design features. Household debris (toilet paper, napkins, food debris, pet hair, polymer films) that has fallen into them remains in the settling chamber and cannot enter the section where the pumps are located. A small amount of chlorine-containing preparations (washing powder, bleaches), which, together with water, entered the VOC of the second type, will also not lead to a loss of system performance.

Both types of devices are volatile - the compressor (pump) must operate in continuous mode. However, complex VOCs have somewhat lower electricity consumption due to the fact that they do not use a compressor, but a timed pump (15 min./on - 15 min./off).

On the Russian market there are systems of varying complexity from both domestic and foreign manufacturers. In some of them, the cleaning process is controlled by a programmable controller that changes the operating mode of the installation based on the amount of incoming wastewater. If there are few of them, the controller switches the system to an economical mode, with volley discharges - to a forced one. Although automation simplifies the operation of the system, it significantly increases the cost of VOC and its further maintenance.

Where to take drains in a country house

When installing equipment, one of the main questions is where the water treated in the installation goes. The easiest option is to divert it by gravity. After treatment in VOCs, wastewater is discharged directly onto the terrain or into a drainage network (trench, roadside ditch) at least 80-90 cm deep, protected from flooding. The second option is a filter well, used in cases where gravity drainage is not possible.

From the VOC, at a distance determined by the project, a reinforced concrete well is made about 3 m deep at the bottom of which crushed stone is poured (in order to increase the system performance). The capacity of the well depends on the type of soil.

In sandy soils, it is 80 l / day. per 1 mg of the area of ​​the outer surface of the filter cylinder of the well, in sandy loam - 40 l / day. In clay soils or at high groundwater levels, this scheme does not work. In these cases, drainage pumps are used. For pumping purified water from VOCs, submersible devices with a conditional passage (maximum size of impurities) of 10-12 mm are used. The pump can be installed directly in the last chamber of the VOC or in an additional intermediate well, it must be sealed. This is necessary so that the pump does not also pump groundwater.

When installing a wastewater treatment system, it is important to consider that it should be located at a distance of 3-5 m from the cottage, so that in winter the effluents coming from the house do not freeze on the way to the VOC

Prices

Manufacturers indicate the cost of installations in different ways. Some call the price only for the equipment itself, others - for the turnkey system, that is, taking into account installation.

When choosing devices for wastewater treatment, it is better to focus on a full range of services. On average, VOC + delivery to the customer's site + installation will cost from 80,000 rubles. (installation volume is designed for four users) up to 140,000 rubles. (for ten users).

For some systems, monthly service activities may be required, the cost of which per year sometimes reaches 20% of the equipment price.

The general rule for all installations is to clean the settling chamber on average once a year from the accumulated excess sludge using a sewage truck. The cost of sewer services is 750-800 rubles / m 3.

What volume of wastewater installation to choose

The choice of a household treatment plant for specific building conditions is a complex multi-factorial task. First of all, it is necessary to calculate the performance of the equipment, since the size of the tank depends on this.

The specific rate of water disposal (according to SNiP 2.04.01-85) is from 200 to 300 liters per person per day and includes the use of a toilet, bath, shower, kitchen sink and washing machine. A family of three to four people spends an average of 200 liters of water per day on washing, washing dishes and washing, another 200 liters on the toilet, and 400 liters on a shower and bath.

In total, 800 liters are obtained. The size of the container is chosen taking into account that its working volume exceeds the daily rate of water consumption by three to five times. Therefore, in our example, a 4 m 3 tank is needed.

Do-it-yourself installation of an aeration station (VOS) - photo

a) Preparation of the subsystem pit b, c) The body of the installation is placed in the pit, d, e) Insertion of underwater and drainage lines into the body of the treatment plant f, g) Installation of electrical equipment, filling the installation with water and sprinkling with sand, h) The outer part of the aeration station

SEPTIC, BIOSEPTIC OR BIOLOGICAL TREATMENT STATION - TO CHOOSE FOR A PRIVATE HOUSE?

Previously, it was more difficult to organize “life support” according to urban standards in rural areas than in space. Fortunately, times have changed, the issue is also being resolved where the connection to the centralized water supply and sewerage is a matter of an unrealistically distant future. It is simply solved locally for one or several households - by drilling an artesian well and choosing an autonomous sewerage system.

What to prefer - a septic tank, a bioseptic tank or a biological treatment plant?

All options for local treatment systems (VOCs) have both “pros” and cons. Let's figure it out!

Local principles

Let's start with some science. It must be understood that any modern device that solves the “toilet” problem (by the way, including the dry closet) works thanks to microorganisms. As a result of the vital activity of these creatures invisible to the eye, biological oxidation processes take place in the effluents. The solid waste fraction decomposes, other organic compounds are formed, and the water settles. Everything is simple, but there is a nuance. Biological oxidation is of two types: aerobic (when the process goes with oxygen access) and anaerobic (without access).

And the bacteria involved in these processes are different. When aerobic are taken into account, the degree of purification complies with current hygiene standards; when anaerobic are working - it does not correspond, and additional cleaning is required.

What is a septic tank

In fact, a septic tank is a sedimentation tank for sewage waste with anaerobic bacteria. Structurally, they are a tank - sealed or without a bottom. There are models consisting of non-

how many containers connected to each other with nozzles and overflows. Heavy particles sink to the bottom, the most liquid fraction sequentially flows from chamber to chamber. Defending in this way, the plums are gradually cleaned.

Theoretically, the more chambers (tanks) a septic tank has, the better and more reliable it is. But in practice, in complex systems, the risk of breakdown is higher, their operation is more expensive, since many components require periodic maintenance. In addition, as a rule, the largest amount of sediment remains in the first section. So it’s not worth unnecessarily complicating the septic tank, three containers are the optimum.

part of a larger whole

A septic tank is not a self-sufficient device. Thanks to anaerobic processes, plums will leave about 65% of pollution in it. Where to put the foul-smelling moisture, which is still far from ideal? It is poured into a drainage well or taken away through the so-called "filtration field" (a piece of land, arranged away from the house in a special way to purify water by filtering it through the soil). Therefore, it is necessary to have this drainage well or a place sufficient for organizing a “filtration field” on your land plot. What to do with the sediment accumulating at the bottom of the chambers? It is periodically raked out. Alas, one cannot do without a vacuum cleaner. This means that it is necessary to ensure the free access of the sewer truck to the septic tank. These points will have to be taken into account when choosing an autonomous sewage system.

"Pros" and "cons" of septic tanks

Maintaining performance after long breaks in use.

Some models do not require an electrical connection.

Low degree of wastewater treatment - up to 65%.

Unpleasant odors are possible in the vicinity of the unit.

Installation requires a significant amount of space on the site.

Access roads are required for maintenance.

Difficult installation of volumetric and heavy equipment.

A septic tank is not the best solution if the groundwater level is high and if the area is clayey.

What is a bioseptic

This is a type of septic tank in which the cleaning process is enhanced by regular loading of bacterial preparations.

Its design provides for a biofilter - a small reservoir with a chemically inert, decay-resistant backfill. It can be, for example, foam balls, shungizite, expanded clay or shell rock. Backfill is an excellent medium for the growth of bacterial colonies and at the same time plays the role of a mechanical filter - it retains solid fragments of sewer drains. The degree of purification in a bioseptic tank is somewhat higher than in a conventional one, and less sediment is formed at the bottom of the chambers. That is, ceteris paribus, the sewer will have to be called less often.

What is an aerotank

In fact, initially the aerotank was called a reservoir in which the treated effluents are mixed with activated sludge - a biocenosis of microorganisms capable of absorbing organic matter. Today, the installation of deep biological treatment, including this tank, is often called an aerotank. What kind of bioseptic? You could probably say that. But, definitely, the difference between an aeration tank and a septic tank with a biofilter is fundamental: other bacteria, aerobic, are used here.

The operation of the system is based on biological oxidation with the access of air, which is pumped by the compressor. Due to aeration, the oxidation process occurs evenly throughout the volume. The "final product" - odorless sludge - is fed into a special compartment. Filtered water does not need additional purification!

ON A NOTE

Any LOS is designed for a certain number of users. To calculate the volume of the treatment plant, it is recommended to start from 200 l/day per person. The volume of simultaneous discharge of effluents (“volley discharge”) is also important. This indicator can greatly affect the quality of cleaning. The greater the throughput of the VOC per day, the more it should have a margin for the simultaneous reception of discharges from various plumbing units within an hour.

"Pros" and "cons" of the aeration tank

A high degree of wastewater treatment - the product is odorless at the outlet.

Possibility of installation in a ventilated basement. The aeration tank does not have to be buried in the ground, like a septic tank (a fan riser is required!).

Space is saved on the site - the "filtering field" is not needed.

In winter, the aerotank is more efficient than a septic tank (aerobic processes occur with heat release, anaerobic processes with absorption).

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

Purification of water from various kinds of impurities present in it, heavy metals and their compounds is a painstaking technological process. Now there are many methods for obtaining a clean liquid, wastewater treatment methods differ in terms of the degree of pollution and the concentration of impurities in the water.

Why clean drains?

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

Cleaning methods

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

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

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

Mechanical

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

cleansing

In the process of settling, particles with a specific gravity greater than that of water settle to the bottom, and those with a smaller one rise to the surface. The lungs include oils, oil, fats, resins. Similar impurities are present in industrial effluents. Subsequently, they are removed from the treatment facilities and sent for processing.

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

Straining and filtering

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

Biochemical

The wastewater treatment system, which uses special microorganisms in the process of working with chemicals, is of two types:

The first carry out water treatment in natural conditions. These can be reservoirs, irrigation fields where additional cleaning of the soil is necessary. They are characterized by low efficiency, high dependence on climate conditions and the need for large areas.

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

1. Aerotanks. Productive biomass is activated sludge. With the help of special mechanisms, it is mixed with the delivered effluents into a single mass.
2. A biofilter is a device where a filter bed is provided. For it, materials such as slag, expanded clay gravel are used.
3. The air filter is constructed according to the same principle, but air is forced into the filter layer.

Biological

Biological wastewater treatment methods are used when there are pollution of an organic nature. A greater effect is observed when using aerobic bacteria. But they need oxygen to keep them alive. Therefore, when working in artificial conditions, air injection is necessary, which leads to an increase in costs.

The use of anaerobic microorganisms reduces costs, but is inferior in efficiency. To increase the quality of filtration, additional treatment of previously processed effluents is carried out. Most often, contact clarifiers are used for this purpose, which are a multilayer filter. Rarely - microfilters.

Wastewater treatment by this method relieves them of toxic impurities, but at the same time they are saturated with phosphorus and nitrogen. The discharge of such water will disrupt the ecological system of the reservoir. Nitrogen removal is carried out in other ways.

Physico-chemical

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

Coagulation

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

flocculation

Flocculation is additionally used to speed up the process in which sedimentation occurs. Molecular compounds of the flocculant, upon contact with harmful impurities, are combined into one system, which makes it possible to reduce the amount of coagulant. The precipitated flakes are removed mechanically.

Flocculants are of various origins: natural (silicon dioxide) and synthetic (polyacrylamide). The speed of the flocculation process is influenced by the order of addition of reagents, the temperature and level of water pollution, the frequency and strength of mixing. The residence time of wastewater in the mixer is 2 minutes, and contact with reagents is up to one hour. After that, the clarification of water in the settling tanks is carried out. To reduce the cost of coagulants and flocculants allows double treatment of wastewater, when the initial settling is carried out without the use of reagents.

Adsorption

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

Wastewater treatment in this way gives high efficiency, allows you to remove various types of contaminants. Adsorption is of two types: regenerative and destructive.

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

extraction

Harmful impurities are placed in a mixture consisting of two liquids that do not dissolve one in the other. It is used when it is necessary to remove organic matter from wastewater.

The method is based on adding a certain amount of extractant. At the same time, harmful substances leave water and concentrate in the created layer. When their content reaches the maximum value, the extract is removed.

Ion exchange method

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

Chemical

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

The following are used as reagents:

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

Neutralization

Wastewater treatment in a similar way neutralizes pathogenic bacteria, brings the pH level to the required standard (6.5-8.5). For this, the following methods are used:

• mixing alkalis and acids in the form of liquids;
• introducing chemicals;
• filter drains containing acids;
• neutralize gases with alkalis and acids with ammonia solution.

Oxidation

When it was not possible to remove impurities mechanically and by settling, oxidation is used. The reagents in this case are ozone, potassium bichromate, chlorine, pyrolusite, etc. Ozone is rarely used because of the high cost of the process and at high concentrations it is explosive.

Recovery process

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

When it is necessary to purify from arsenic, mercury, chromium, this method is used.

Flotation

Flotation Method - High Pressure Air Cleaning

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

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

Recycled sludge that is the result of domestic wastewater treatment and some industries can be used by agriculture as fertilizer.

Alex , 20 May 2017 .

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The chemical method of wastewater treatment is usually used in industrial production, where, as a result of activities, water is polluted with various substances. In order to remove various impurities from polluted water, special reagents are added to it, which help to form sparingly soluble substances that precipitate. The chemical method of purification also involves the disinfection of already purified water using chlorine-containing reagents that destroy pathogens.

Mechanical wastewater treatment

Mechanical wastewater treatment helps to remove large debris and particles of mineral origin, which are in the effluent in an undissolved suspended state. During mechanical treatment, wastewater passes through sand traps, grates and special filters, then it settles in a sump, where it is partially filtered and clarified. This method is used immediately before biological treatment.

Biological sewage treatment

Biological treatment is designed to free wastewater from organic compounds dissolved in it. This process involves special groups of microorganisms: aerobes, which develop only in the presence of oxygen in the wastewater, and anaerobes, which require oxygen deficiency. Accordingly, cleaning can be aerobic and anaerobic. Modern wastewater treatment plants use a combination of anaerobic and aerobic treatment, which gives excellent results.

Aerobic purification takes place in aerotanks, in septic tanks with a biofilter, in filtration and absorption fields, in filter wells with natural and forced air supply. Forced air supply is created in treatment plants using compressors. In all other cases, oxygen comes from the surrounding air. This chemical element is the main one in the process of vital activity of aerobic bacteria. In the presence of oxygen, aerobes begin to actively multiply and feed on organic pollutants, resulting in intensive purification of wastewater. In parallel, the formation of activated sludge in the treated water is observed. Activated sludge is a very useful substance, as it mixes with sewage and causes the oxidation of dangerous organic compounds, turning them into simple and harmless components. As a result, the water is freed from bacterial contamination, becomes transparent, and loses the unpleasant smell of sewage.

The advantage of aerobic treatment is the almost complete purification of wastewater from organic matter. Anaerobic purification occurs without air access. For this, special closed tanks are made, where oxygen deficiency is created.

Such conditions are favorable for anaerobic bacteria, which are involved in the fermentation and decomposition of organic matter into water, methane, carbon dioxide and other simple compounds. Anaerobic treatment takes place in septic tanks, metatanks and special two-tier settling tanks.

• Heating pipes with a heating cable and other methods of insulation

Wastewater treatment is an indispensable process, as it makes sewage waste safe for people and the environment. Today, technological progress negatively affects the water resources of our planet, so every drop counts. For this reason, treatment methods have been developed that help the effluent to be reused for irrigation of land or simply replenishing the soil. In today's article, we will discuss with you the main ways to filter sewer fluid.

To begin with, let's find out what refers to the concept of wastewater? For this understanding, it is customary to take all the liquid with and without impurities, which is drained into the sewer system. Its important characteristic is the presence of pollution obtained in a certain field of application. It is worth considering that the liquid of atmospheric precipitation is also read here.

Types of pollution

Wastewater treatment involves a process that takes place with the right selection of equipment. It is worth considering that its important component is compliance with a certain type of pollution. It is for this reason that let's find out their species that may be in wastewater:

• Mineral pollution. This type includes all inorganic components, such as: salt, earth, etc.
• organic matter. This is a sewage liquid containing in its composition the remains of the world of flora and fauna. Their composition usually consists of chemical organics and polymers.
• Biological components. They are bacteria and other various microorganisms.

Attention! In most cases, a sewer drain incorporates all three components. If these are household drains, then organics will relate to minerals as 3 to 2. As for bioorganisms, their number depends on the environment.

Norms for cleaning

Any water treatment plant is required to perform a certain level of processing. It should be noted that regulated strict standards are prescribed only for the industrial sector. In addition, the ratio of each type of impurity is fixed by law. For example, iron after treatment should be present in an amount of not more than 0.1 mg per liter.

In relation to domestic plums, the requirements are more lenient. But this is no reason to relax. One of the most important rules for managing wastewater on a private property is that untreated wastewater cannot be released into the environment. For violation of this regulation, the owner of the house will be held administratively liable.

Important! To date, the state regulates only the maximum possible amount of impurities in water. At the moment, this only applies to draining into a reservoir. But remember that the test can also make these claims in relation to the withdrawal of runoff into the soil.

Wastewater Treatment Methods

Based on the variety of methods for filtering and treating wastewater, today they can be divided into types. Namely, there are two types of wastewater treatment methods:

• destructive species;
• recovery methods.

For the former, a characteristic feature is the process of dividing effluents into simple components, which can later be easily removed, for example, in the form of gas. The second types select all valuable substances from the sewage liquid in order to process them in the future.

The cleaning process - how to do it

Technological progress does not stand still, and therefore every day there are new ideas and ways to purify wastewater. After all, do not forget that this is an additional water resource. In this section, we will get acquainted with each of the types separately, but first, let's list them:

• Mechanical;
• biological;
• Physical and chemical;
• Method of disinfection;
• Thermal recycling.

Consider in detail the methods of wastewater treatment.

mechanical way

This is one of the simplest options. The process itself includes the removal from the drains of all components that do not dissolve. What are these components? First of all, these include solid particles and fat. Sewer water is passed through a sieve and a sump, which then only passes liquid with small particles.

The best option for mechanical treatment of sewage water is the membrane method. Its main feature is nothing less than the best purification process. The main thing is not to forget that this type of filtration gives a result of 70% and is the start for the biological method.

Biological cleaning process

Wastewater treatment with biological substances is carried out using the functioning of bacteria and microorganisms in the system. Their main feature is the ability to oxidize solid particles. The basis for the creation of this method was the microflora of natural water sources. Studies have proven that drains get rid of nitrogen and phosphorus, which are dangerous for the environment. Bacteria are of the following types:

• Anaerobic microorganisms that can function without air;
• Aerobic types cannot work without oxygen.

If cleaning is carried out with the help of air, that is, aerobic bacteria, then it is possible to install a biofilter or aeration tank. These designs have a high cleaning efficiency and can deal with activated sludge. With anaerobic microorganisms, a fermentation process occurs that converts organic matter into methane and carbon dioxide.

Biofilters and aerotanks with activated sludge are used for such cleaning. They are highly purified and more efficient than biofilters for wastewater treatment. In aerotanks, water is aerated and its deep biological treatment is carried out. In addition, the result is activated sludge, which is a good fertilizer. Anaerobic wastewater treatment is carried out without access to oxygen. Under the influence of anaerobic bacteria, the process of fermentation and the conversion of organic matter into methane and carbon dioxide occurs. It is worth noting that the second method is slightly cheaper.

Attention! In modern devices, two types of microorganisms are used, which can be easily used even in industrial sewers.

Physical and chemical method

These wastewater treatment methods are very effective and are based on the teachings of the sciences of chemistry and physics. These types include:

• Electrolysis is a very popular method in industrial plants. The basis of the treatment process involves breaking down the organic constituents of the water to produce inorganics.
• Coagulation is the purification of water, which is carried out when the components stick together under the action of forces. The result of the process is the formation of an aggregate.
• Precipitation of metal hydroxide flakes- this action is the result of the influence of coagulants, which cause precipitation. Educated flakes are engaged in wastewater treatment.

The physico-chemical process has a large number of advantages, for example, the removal of toxins and impurities that are not able to oxidize. It is also worth adding that this method provides a very high percentage of cleaning. This method can easily automate the dimensions of structures for filtering, which will reduce the sensitivity of the action.

Disinfection

This method is reproduced by exposure to ultraviolet rays, chlorine or ozone. Typically, the method is used to disinfect water before being discharged into a reservoir. The most effective process is considered to be with the use of rays, as it is safe. It is worth considering that their impact can have a detrimental effect on bacteria and various viral microbes.

The type of cleaning based on chlorination implies the disinfection of all microorganisms with chlorine. The main disadvantage of this mechanism is the creation of toxins and carcinogenic compounds. For this reason, you should be very careful when using this method.

Ozonation is the treatment with ozone. Everyone knows that this is a type of gas that contains three oxygen molecules, thereby forming a powerful oxidizing agent that kills microbes. It is important to say that this method is very expensive, so it is used very rarely in everyday life. The main scope of its use is manifested in the production of industrial sectors.

Thermal disposal

Thermal treatment of sewage effluents is carried out in situations where other methods fail. The principle of operation is to spray the liquid in the combustion fuel torch. This is a very effective method, but due to its price and volume, it is found mainly in production.

Attention! Modern treatment plants perform a process in several steps, so they are often programmed to use several methods.

So, the process of purification of sewage water is a prerequisite for the operation of the wastewater disposal system. It should not be overlooked that these requirements are regulated by sanitary and legislative norms.