Methods of domestic wastewater treatment and norms. Existing methods of domestic wastewater treatment.

Mankind has accumulated vast experience in organizing the disposal of polluted water flows. Historical sources testify to the existence of systems for the removal of domestic wastewater in India and China, about 5-6 thousand years old. The ancient Greeks in Athens used a 4.2 m wide canal to drain wastewater. Ancient Rome in the 6th century BC e. a large closed drainage system was built, some parts of which were used until the beginning of the 20th century.

Alas, the need to purify used water before its subsequent consumption, mankind has learned from its own negative experience.

The unsanitary state of cities in all countries of Western Europe contributed to the spread of epidemics of plague, leprosy, smallpox, and typhus. For the first time, quality standards for wastewater discharged into water bodies were approved in England after the cholera epidemic in 1831. At the same time, the construction of irrigation fields for biological wastewater treatment was organized.

In Russia, the first drainage facilities appeared in the 12th century in Novgorod. A serious achievement of technical progress in water management construction is the sewage system of the Zmeinogorsky gold mine, built in Siberia in the 18th century. This complex structure served three mines, an ore processing plant, a forge and a saw mill. The total water consumption was 17.3 thousand m3/day, and the total length of the system was about 2.5 km.

In Moscow, the first drainpipe was laid in the 14th century from the former central Ivanovskaya Square (not far from the walls of the modern Kremlin) to the Moskva River. In 1898, the first drainage system was put into operation in Moscow, including gravity and pressure drainage networks, pumping station and Lublin irrigation fields. Then it became the largest sewage and wastewater treatment system in Europe.

At present, thanks to the achievements of technological progress, the problem of water disposal and treatment of municipal wastewater has been implemented at a high level. Modern treatment facilities provide a high degree of environmental protection. But unfortunately, in many settlements where there is no central sewerage system at all, the current situation resembles medieval Europe. There, the disposal of wastewater and their purification become the problems of the residents themselves, and it is already customary to solve it with the help of equipment. country houses autonomous sewage systems, and those that, unlike cesspools, clean, and do not accumulate (accumulate) polluted water.

Wastewater treatment methods used in local sewage systems can be divided into three main types:

• mechanical,
• chemical,
• biological.

Let's consider each of them separately.

At mechanical way purification occurs sedimentation and filtration of wastewater. One of the disadvantages of this method is that water is not purified from dissolved organic contaminants. Therefore, structures mechanical cleaning(settlers, sand traps, grates and sieves) are most often used as a preliminary stage before biological treatment.

The chemical method of wastewater treatment is based on the use of various reagents, under the influence of which dissolved impurities form sparingly soluble compounds, which subsequently precipitate. However, the reagents used are quite expensive, and in addition, it is required to observe their exact dosage. That's why chemical method, mainly used for the treatment of industrial wastewater.

It should also be borne in mind that neither mechanical nor chemical methods cleaning does not solve the problem of waste disposal. Therefore, we will dwell on the biological method of purification in more detail. Polluted water entering the drainage network from residential buildings, household premises industrial enterprises, combines Catering differ in the relative constancy of their composition. A large amount of organic substances in them creates a favorable nutrient medium for microorganisms (bacteria), which are able to absorb various organic substances in the course of their vital activity. It is on this property that biological method domestic wastewater treatment. In the process of respiration of microorganisms, harmful organic substances are oxidized, and decompose into harmless ones. Thanks to this, the waters lose their tendency to decay, become transparent, and their bacterial contamination is significantly reduced.

Bacteria are involved in the biological treatment of wastewater, which, depending on their nature of interaction with oxygen, are divided into two groups: aerobic (the vital activity of which is supported by oxygen dissolved in water) and anaerobic (developing in the absence of free oxygen).

Anaerobic (without air access) cleaning is carried out in reinforced concrete tanks (methane tanks, septic tanks, two-tier settling tanks), where the process of fermentation of organic pollutants occurs with the help of methane-forming bacteria. The main disadvantage of anaerobic treatment is the release of biogas (methane), and, as a result, the formation unpleasant odors which is not only unpleasant, but also unsafe.

The operation of most modern treatment facilities is based on the use of aerobic processes. Aerobic treatment takes place in irrigation fields, filtration fields, in biological ponds, canals, biofilters, in special containers - aerotanks.

For construction autonomous systems sewers are most convenient biofilters or aerotanks. In these systems, conditions are artificially created under which the vital activity of microorganisms occurs most intensively. Let us consider in more detail what is the principle of their action, and the differences from each other.

The biofilter is a tank with a double bottom filled with coarse-grained filter material (expanded clay, slag, gravel, etc.). Wastewater, passing through the filter material, forms on its surface a biological film of accumulations of microorganisms that destroy the organic matter of wastewater.

Aerotank - a reservoir into which an intensive supply of air is carried out (this process is called aeration). During biological treatment in the aerotank, activated sludge is created from particles suspended in the waste liquid with microorganisms multiplying on them, which significantly accelerates and improves the processes of oxidation and wastewater treatment, absorbs organic matter and bacteria. Microbes, including pathogens, are adsorbed by activated sludge, die or become its active agents. The aerotank differs from the biofilter in the larger surface of the filter layer. And the presence of an air supply device ensures high oxidizing power. It is generally recognized that the aerotank is the most efficient facility for the biological treatment of domestic wastewater. It has been widely used in large wastewater treatment plants for many years.

Today on Russian market a significant number of modern treatment systems of domestic and foreign production are presented. However, without special knowledge, evaluate the advantage of one or another of them and make right choice very difficult. The selection strategy must be approached carefully and seriously, since the treatment system is purchased and installed for a long time, not for a dozen years. The first step in this direction should be the search for a trading company that is competent in the field of engineering and construction of wastewater treatment plants, capable of providing competent design, high-quality installation, technical support and service during operation. The uninterrupted operation of the local cleaning system (VOC) and, of course, the comfort in your home will depend on this. It is advisable to get from the company's managers a simple, but useful information about the chosen system:

• information on the completeness of the treatment process (cleaning, post-treatment, water disposal) and the efficiency of wastewater treatment;
• the presence of a hygienic conclusion;
• service life and quality of materials;
• ease and safety of maintenance.

The final decision on the issue is made on the basis of a study of local conditions and depends on many components:

• soil type, its granulometric composition, moisture capacity and water permeability;
• level ground water and its seasonal fluctuations;
• depth of soil freezing (average long-term, maximum and minimum values);
• the size of the site and the nature of its relief (leveled, wavy);
• operating mode of the system (seasonal, year-round);
• location of water intake facilities.

Until recently, any attempt to produce small aerotanks (for use as treatment plants for country houses or small cottage settlements) led to an increase in the cost of equipment, or a decrease in the quality of treatment. This problem was solved by the Czech engineer Jan Topol, who developed the TOPAS deep biological treatment plant.

Wastewater treatment plants (WWTP) model range"TOPAS" are developed on the basis of the experience of large wastewater treatment plants with fine bubble aeration, both intermittent and continuous. The above processes are combined in this installation.

Unique technology, easy installation, compact system, silent self-cleaning automatic operation with minimum requirements and maintenance costs, signaling the normal operation of the WWTP and high-quality water treatment (98%) - these are the factors determining the repeated victory of the WWTP "TOPAS" international exhibitions(in 1996, 1998, 1999 and 2001) and the recognition of this installation in Germany, Canada, the Czech Republic, Slovakia and Russia, confirmed by certificates from these countries. The units are delivered ready for use, have small size, light weight and are a single body made of a polypropylene panel with a foamed inner layer, which gives them the necessary strength and prevents corrosion damage from the aggressive effects of wastewater. Installation of "TOPAS" does not require significant engineering work, special equipment and qualified performers. It is only necessary to deepen the installation into the soil, connect the sewage pipeline and the electric power cable for a small-sized and economical Japanese-made magnetic-induction compressor.

The installations inside are divided into a number of process tanks that perform the following functions:

• accumulation and equalization of wastewater;
• aeration;
• biological treatment using activated sludge;
• accumulation of excess activated sludge;
• clean water sump.

The division of functions occurs depending on the position of the float switch of the water level in the storage tank.

TOPAS units are produced in various standard sizes depending on water consumption and the number of consumers served.

Wastewater treatment plant BIOTAL are produced in Moscow under license from the Czech company Teterja Alexandring. since April 2000. During this time, the system has proven to be reliable and convenient device for the treatment of domestic wastewater for both a separate building and a whole cottage settlement.

The device is made of polypropylene. It is not chemically active, does not corrode, does not allow moisture to pass through, has small dimensions and low weight. Due to these properties, the service life of the treatment plant is 25-50 years, and the cost of construction and installation work is relatively low.

The cleaning process is controlled by a microcomputer, to which bioreactors, an aerobic stabilizer, an automatic dispenser, a compressor, aerators, and airlifts are connected. This allows you to optimize ongoing processes in terms of energy consumption and equipment resource.

All internal elements of the system are removable. In case of repair or maintenance of the installation, wastewater pumping is not required.

One more distinctive feature BIOTAL from similar systems is the presence of two economical modes, with which it is possible to reduce electricity consumption by up to 70%. In the event of a power outage, the installation does not lose functionality - it continues to work as a five-stage sump, still providing wastewater treatment from fats and surface impurities (the main enemies of drainage systems). When the power supply is restored, the system automatically starts to work in the previous mode.

Some advantages of the BIOTAL system:

• a sewage truck is not required to remove cleaning products, so the installation can be located anywhere;
• consumables are not used during operation;
• computer control automation;
• overall dimensions of the system are relatively small, which reduces the volume construction works and occupied area;
• the possibility of installation without the use of heavy equipment, because system weight - from 150 to 280 kg.
• low power consumption.

Want to create a communal paradise on your suburban area but you can't connect to centralized system sewers? This means that cleaning household wastewater can become a serious problem.

In order for you to solve it with the least financial expenses and the greatest efficiency, the company offers its KLEN country septic tanks, created using innovative technologies. Wastewater treatment in them occurs in stages and deeply.

Can't see, can't hear!

So you can characterize the work equipped with this septic tank:

• "not visible": because the structure is underground, only hatches of wells for Maintenance arranged on the surface, but they organically look next to the rest of the household buildings;
• “not audible”: due to the fact that the septic tank works silently;

An ordinary septic tank is a structure in which only domestic sewage is settled, as a result of which heavy pollution settles to the bottom, and light ones float to the surface. The efficiency of such clarification of the waste liquid is a maximum of 60%, and this is clearly not enough in the context of the tightened requirements of the new Water Code.

The fundamental difference between a septic tank for giving KLEN and its "brothers" is biological treatment, carried out in a special block with brush loading.

Effluent treatment stages

The design of the KLEN septic tank is extremely simple: it is a container consisting of a primary, secondary settling tanks, a biofilter and a storage tank (in models with the letter “H”). You should immediately pay attention to the names of the sections: they are the same as in local facilities(VOC), where there is a complete cleaning and disinfection of domestic wastewater. And this is no coincidence, because in the KLEN septic tank the process goes according to a scheme similar to VOC:

1. In the primary clarifier, mechanical (under the influence of gravity) separation of wastewater into raw sediment and floating substances takes place.
2. Further, the clarified water enters the secondary sump, where small fractions are already deposited, and the biological purification of dissolved contaminants begins with the help of anaerobic bacteria.
3. Then the partially purified water moves to the biofilter, where, thanks to the drip sprinkler, it is saturated with air and evenly distributed over the brush load. Here the biological purification of the remaining contaminants takes place under the influence of already aerobic microorganisms.

From a biofilter water is coming either into the accumulator, or immediately into a perforated pipe, from where it enters drainage system, and then goes into the soil, becoming a kind of additional source of watering plants.

Thanks to the use of a biofilter in KLEN country septic tanks, the efficiency of domestic wastewater treatment reaches at least 85%.

Lightweight, durable, reliable

The body of the septic tank is made of sheet polypropylene, making the construction is quite easy. For example, the KLEN 5 model, designed to receive 450 liters of household wastewater per day, weighs only 52 kg. Polypropylene is not subject to corrosion damage, is resistant to external mechanical influences, does not allow moisture and air to pass through, ensuring absolute tightness of the septic tank.

When choosing a place to install it, you need to remember the following:

• according to sanitary and hygienic standards, the distance from the sewage treatment plant to the well or well must be at least 10 m;
• it is necessary to provide access to the septic tank of a sewage truck for pumping out sediments that are formed in the process of processing household wastewater;
• the optimal distance to residential and household buildings should be from 2 to 20 meters.

Another important point- choice of septic tank model. In order not to be mistaken, it is better to consult with experts. First of all, the number of people living in the house and the frequency of their appearance there matters. For a family of 3 to 5 people, the KLEN 5 model is suitable, which can take up to 450 liters of domestic wastewater per day. If there are 5-7 people in the house, then you will need to mount a septic tank KLEN 7, it will be able to purify household fecal water in the amount of 750 l / day.

The second factor that is of great importance when choosing a model of a country septic tank is the depth of the groundwater level. Many manufacturers of domestic wastewater treatment plants do not focus on this issue, but the company's specialists consider it fundamental.

It is necessary to carry out the installation in such a way that the pipe for the release of treated domestic wastewater into the drainage system is above the groundwater level. If it is low, then it is recommended to choose KLEN 5, KLEN 7 (3-chamber version), and if it is high - the same models, but with the letter “H” (4-chamber version with a storage tank of fecal water cleaned from pollution and submersible pump for their supply to the drainage pipe).

To determine the characteristics of the groundwater level, you can invite specialists who will make all the necessary measurements and calculations. And the representatives of the company will install the septic tank in one day, doing everything so that the cleaning of household fecal water in your area is always carried out in the normal mode.

Everything is perfect: quality, price, level of service

In terms of the efficiency of their work, KLEN septic tanks are quite comparable with. After all, the biological treatment carried out in them makes it possible to achieve such outlet water parameters that fully meet sanitary and hygienic standards.

However, the price of a septic tank for giving KLEN 5n with a set of extensions for necks and a household fecal pump "Dzhileks" is 41 thousand rubles. VOCs of similar performance will cost an average of 20 thousand more.

But not only the price favorably distinguishes the KLEN septic tank from the VOC: the cleaning of domestic wastewater is carried out in it with virtually no electricity consumption. In principle, KLEN septic tanks can be called non-volatile.

But VOCs are not such: in the aerotank, where biological treatment is carried out, a constant supply of air by a compressor is required. No less air is needed for the operation of airlifts, pumping a mixture of treated household wastewater with sludge into a secondary sump. A power outage will be a disaster: without air supply, the aerobic biocenosis will die, with the help of which domestic wastewater is cleaned from dissolved contaminants. To restore the performance of the LOS after an emergency stop, you will need the help of specialists.

If you decide to carry out the installation of the structure yourself, then the company's employees will give free consultations on this topic. They will tell you how to make the treatment of domestic wastewater always efficient.