RU2440307C2 - Method for biological treatment of waste water - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: first, waste water containing insoluble mechanical impurities on which organic substances are adsorbed is treated in a pre-aeration reservoir, at the input of which active sludge is fed from a settling tank. Waste water containing pure insoluble mechanical impurities from which organic substances have been removed, and active sludge are taken from the pre-aeration reservoir for mechanical purification. Effluent containing active sludge and easily digestible organic material transferred into the solution is fed into a bioreactor having zones with alternating oxygen content while also feeding air, and then into a settling tank, also having zones with different oxygen content. From the settling tank, active sludge is returned into the bioreactor and the pre-aeration reservoir to form a closed waste water purification cycle.

EFFECT: automation of the biological treatment process while reducing the industrial load on the environment and cutting energy, operational and capital expenses on constructing treatment facilities.

14 cl, 1 dwg, 1 tbl

Description

Technical field

The invention relates to the biological treatment of wastewater and can be used in utilities, various industries and agriculture for the treatment of domestic, industrial and similar wastewater composition containing biodegradable substances.

State of the art

The problem of known methods of biological treatment is the increased technogenic load on the environment due to the formation of large enough volumes of excess activated sludge, which leads to the need to use equipment for its processing and storage, the use of reagents used in the treatment of sewage sludge, and the construction of landfills for burial precipitation. All this leads to secondary environmental pollution and the need to use additional land resources.

Another problem is the problem of emissions of harmful substances, including those that smell unpleasant, including hydrogen sulfide, from precipitates collected in sewage into the atmosphere, and the need for this to increase the size of the sanitary protection zone - the distance from treatment plants to residential buildings.

In addition, the need for continuous removal of secondary contaminants - crude sludge from primary sumps and excess activated sludge from secondary sumps - does not allow the creation of a closed technological cycle of wastewater treatment, which makes automation of the whole process as a whole impossible and excludes the operation of treatment plants with guaranteed quality of treated wastewater, while reducing the environmental footprint with the exception of on-duty personnel (i.e., excluding the impact of “human fact” RA ").

Known methods of biological treatment, including two stages - mechanical treatment and biological treatment.

At the first stage, water-insoluble substances in suspension are removed; at the second stage, what remains of the first stage is suspended and dissolved in wastewater.

The disadvantages of the method include:

- the formation of secondary pollution in the form of crude sludge in the primary sedimentation tanks in the first stage,

- large volumes of excessively activated sludge formed during biological treatment (secondary pollution).

A known method of biological wastewater treatment (US Pat. RU No. 2220918, op. 10.01.2004), according to which the wastewater after mechanical treatment is sequentially fed to an anaerobic bioreactor, an aerobic bioreactor, a sump equipped with airlift with an activated sludge recirculation pipeline, a post-treatment bioreactor with loading for attached microflora and disinfection chamber. The method provides a reduction in the amount of precipitate formed, which is removed from the anaerobic bioreactor, then it is dehydrated, for example, in filter bags.

The disadvantages include the fact that the method does not solve the problem of minimizing the formation of excess sludge.

A known method of biological wastewater treatment (US Pat. RU No. 2170217, op. 10.07.2001), in which wastewater, previously mechanically treated in the primary settler, is fed to the treatment tank for processing, in which the presence of zones with a dissimilar oxygen content is maintained Wednesday. Next, the mixture of wastewater with activated sludge enters the secondary sump for separation into treated wastewater and activated sludge, which is constantly returned to the beginning of the activation tank.

The disadvantages of the method include the formation of significant volumes of crude sludge in the primary sump and excess activated sludge removed for disposal, which increases the cost of operating treatment facilities, reduces the efficiency of treatment facilities.

A known method of biological treatment, including the supply of wastewater to the pre-treatment chamber, then treatment with activated sludge in an activation tank divided into aerobic and anaerobic zones, with periodic air supply, separation of the sludge mixture in the sump with the return of activated sludge to the activation tank (RU patent No. 2299864, op. May 27, 2007).

Intermittent aeration during the implementation of this method at wastewater treatment plants of medium and high productivity will cause additional costs and complexity in controlling the process.

With the spatial separation of aerobic and anaerobic zones, the minimum formation of activated sludge is not provided, because there is no self-regulation of the process, which can be ensured only by conditional separation of zones due to the presence of transition zones where a specific microflora is formed, which ensures the stability of the biological treatment process when the composition and quantity of wastewater entering the treatment is changed (“super-unstable regime”) and increase the efficiency of microorganism metabolism activated sludge.

In addition, the method does not solve the problem of harmful emissions, including unpleasant smelling, when removing raw sludge, there is no possibility of automation of the wastewater treatment process.

A known method of biological treatment (Eurasian patent for invention No. 004338, op. April 29, 2004), comprising supplying wastewater without mechanical pretreatment to an equalizing tank into which air is periodically supplied to grind coarse mechanical impurities, treating wastewater in an activation tank when applying air into it, where they are biologically cleaned, treated wastewater is supplied to the sump, where activated sludge is separated from treated water, activated sludge is fed from the sump to the activation tank .

In this method, the issue of removing insoluble impurities with organic substances adsorbed on them is not solved, but only those impurities that are dissolved in water and mechanical impurities that can be broken by an air stream are removed. The problem of the release of harmful substances, including unpleasant smelling ones, into the atmosphere has not been sufficiently solved, since the issue of removing harmful organic impurities at the initial stages of the process is not considered.

The existing method is applicable for wastewater treatment at small treatment plants and cannot be applied at large plants due to intermittent process, because the process itself and its management become much more complicated.

In addition, during intermittent aeration, the process of decomposition of organics adsorbed on insoluble impurities (not subject to biodegradation) is not fully carried out and biological treatment of wastewater with minimal formation of excess activated sludge is not carried out in full, which requires its removal from treatment facilities.

The closest analogue adopted for the prototype is a method that includes mechanical treatment of wastewater in the primary sump, after which the wastewater is fed into a bioactivator (bioreactor), in which the presence of zones with a heterogeneous oxygen content is maintained by means of controlled oxygen input, and then the mixture sewage with activated sludge enters the secondary sump for separation into treated wastewater and activated sludge, which is constantly returned to the beginning of the bioreactor. The crude sludge after the primary sump is recycled to the input of the primary sump to create the conditions for the hydrolysis process and the heteroacetogenic process directly in the primary sump. In the secondary sump, zones with a heterogeneous oxygen content are created by controlling the rate of recirculation of activated sludge from the secondary sump to the bioreactor inlet. Zones with a heterogeneous oxygen content in the bioreactor are distributed in the horizontal direction (patent RU No. 2296110, op. 2007.03.27).

In this method, the minimum volumes of excess activated sludge are achieved in comparison with the known methods, but the technological process is not closed, due to the fact that the technological stages are separated and there is a need to remove sludge from the primary sump, therefore it is impossible to automate the biological treatment process control system, adjustment can only be done manually.

Sludge removed from primary sedimentation tanks includes mechanical impurities insoluble in wastewater containing adsorbed organics, which quickly decomposes when they are removed from the effluent (anaerobic process takes place) in storage areas, releasing microorganism exchange products into the environment - harmful substances , including unpleasant smelling.

As a result, sanitary protection zones of treatment facilities require significant areas, which increases the environmental load on the environment.

Disclosure of invention

The present invention is the creation of a fully automated biological treatment process due to the closed technological cycle, while reducing capital and operating costs and reducing the environmental load on the environment.

The problem is solved as follows.

In the method of biological wastewater treatment, including the treatment of wastewater in a bioreactor, with zones alternating in oxygen content when air is supplied to it, the supply of treated wastewater to a sump, which also contains zones that are heterogeneous in oxygen content, where the biological treatment process with activated sludge continues the subsequent separation of the treated effluent and activated sludge and the return of activated sludge from the sump to the bioreactor, according to the invention, wastewater containing insoluble furs is initially treated organic impurities with organic substances adsorbed on them, in the preliminary aeration tank, to the input of which activated sludge is fed from the sump to decompose organic substances adsorbed on insoluble mechanical impurities, which go into the solution in the form of easily digestible organic substances, after the preliminary aeration tank wastewater containing pure insoluble mechanical impurities, freed from organic substances sorbed on them, and activated sludge, go to mechanical cleaning to remove the indicated insoluble solids from the effluent, then the effluent containing activated sludge and easily digestible organic substances that have passed into the solution are fed into the bioreactor and then into the sump, from which the activated sludge is returned to the bioreactor and preliminary aeration tank with the formation of a closed wastewater treatment process .

The wastewater level in the pre-aeration tank is kept constant with continuous air supply.

The residence time of the mixture of wastewater and activated sludge in the pre-aeration tank is 45 minutes - 1.5 hours.

The amount of activated sludge supplied from the sump to the preliminary aeration tank is 5-10% of the total amount of recycled sludge.

The oxygen concentration of the water mixture in the pre-aeration tank is maintained at 2.5-3.5 g O ₂ / m ³ .

The bioreactor is conditionally divided into successively alternating zones with a heterogeneous oxygen content medium, the first of which, preferably, is anaerobic.

The number of zones in the activation tank is an even value - at least two.

The oxygen concentration in the anaerobic zone of the bioreactor is not more than 0.7 g O ₂ / m ³ .

The oxygen concentration in the aerobic zone of the bioreactor is at least 2.5 g O ₂ / m ³ .

The amount of activated sludge entering the bioreactor is 90-95% of the total amount of recycled activated sludge.

The concentration of activated sludge in the bioreactor is 2.5-7.5 g / DM ³ .

The ratio of the volumes of anaerobic and aerobic zones in the bioreactor is 1: 1

Mechanical treatment of wastewater containing insoluble impurities freed from organic matter adsorbed on them is preferably carried out by filtration, which is carried out on sieves with a mesh size of 2-5 mm sieves.

The oxygen concentration in the water-oil mixture in the bottom of the sump is 0.1-0.3 g O ₂ / m ³ , and at a depth of 1 m in the sump - 2-2.5 g O ₂ / m ³ .

The introduction of the pretreatment stage of wastewater in the pre-aeration tank, to the entrance of which activated sludge is supplied from the sump, allows decomposing the organics sorbed on insoluble mechanical impurities into simpler, easily digestible organic compounds that go into solution and are subsequently absorbed by microorganisms of activated sludge in the bioreactor minimally short time, therefore, a smaller volume of the bioreactor is required, which reduces the capital cost of construction facilities in general.

The pre-aeration tank does not perform the function of a receiving tank and is used as the first stage of biological treatment, namely, for the decomposition of organics sorbed on mechanical impurities.

Subsequent removal of these insoluble impurities in the mechanical cleaning device helps to ensure that mechanical impurities freed from sorbed organics do not emit harmful (including unpleasantly smelling) substances into the environment at the places of their processing and storage.

The set of distinctive features, namely, the supply of activated sludge from the sump to the pre-aeration tank, the further supply and treatment of wastewater in the bioreactor with alternating oxygen concentration zones, and then the wastewater to the sump, from which the activated sludge is returned to the pre-aeration tank and the bioreactor , creates a closed technological cycle of wastewater treatment and allows you to automate the management of the entire biological treatment process.

Maintaining a constant level of wastewater in the pre-aeration tank does not require level control devices, simplifies the operation of treatment facilities.

Biological treatment of pre-treated wastewater containing easily digestible organics in a bioreactor with alternating zones of oxygen concentration ensures the decomposition of nutrients (C, N,) received at treatment plants with wastewater with minimal increase in activated sludge.

Moreover, an important factor is that the treatment of effluents in the bioreactor preferably begins in the anaerobic zone. Activated sludge in the anaerobic zone removes organic compounds and uses them to maintain its activity, while the products of the metabolism of microorganisms of activated sludge are partially gaseous substances that contribute to the enlargement of small microorganisms, which also ensures a minimum volume of activated sludge.

If wastewater immediately enters the aerobic zone, activated sludge also removes organic compounds, but with a maximum increase in sludge, as under aerobic conditions, organics dissolved in wastewater is used by activated sludge microorganisms for their nutrition and reproduction, which increases the volume of sludge, which is subsequently stored, and requires its removal from the system and further processing.

Alternation of zones of different oxygen contents in the activation tank leads to a change in the metabolism of activated sludge microorganisms and a biocenosis shift in the activated sludge towards “predators” (larger microorganisms), which ensures a minimum increase in activated sludge.

Minimization of the volume of activated sludge formation allows eliminating from the technological process the stages of sludge removal from the technology and its further processing, which are an integral part of all known wastewater treatment processes, which ultimately makes it possible to create an algorithm for the complete automation of the wastewater treatment process in the present method.

An embodiment of the invention

The method is illustrated in the drawing, which shows a diagram of the proposed biological wastewater treatment, where

1 - pre-aeration tank,

2 - mechanical cleaning device,

3 - bioreactor,

a, b - respectively anaerobic and aerobic zones into which the activation reservoir is conditionally divided,

4 - sump

b, a - aerobic and anaerobic zones, respectively, into which the sump 4 is conditionally divided,

5 - sewage supply pipe,

6 - pipeline supply of activated sludge from the sump to the preliminary aeration tank,

7 - pipeline supply of activated sludge from the sump to the bioreactor,

8 - aeration system,

9 - aeration elements with a middle bubble,

10 - aeration elements with a small bubble,

11 - pipeline for supplying air to the preliminary aeration tank,

12 - pipeline for supplying air to the bioreactor,

13 - release of treated wastewater.

The method is as follows.

Wastewater containing insoluble impurities with organic compounds contained in them, without mechanical pretreatment, enters the pre-aeration tank 1, in which organic compounds sorbed on insoluble impurities are biodegradable by microorganisms of activated sludge coming from the sump 4. In the pre-aeration tank 1 maintains a constant upper level of wastewater. Air is continuously supplied through the pipe 11 to the tank 1, and activated sludge is continuously supplied to the tank 1 from the sump 4 through the pipe 6 to decompose organic compounds adsorbed on insoluble mechanical impurities. The amount of air supplied to the pre-aeration tank 1, maintains the oxygen concentration in the water mixture in the pre-aeration tank 1 at a level of 2.5-3.5 g O ₂ / m ³ . The amount of activated sludge supplied from the sump 4 to the pre-aeration tank 1 is 5-10% of the total amount of recycled sludge.

The necessary time for the process in the pre-aeration tank 1 is 45 minutes - 1.5 hours, depending on the amount of organic compounds in the wastewater. If the process time is less than 45 minutes, the desired effect on the decomposition of organic compounds adsorbed on insoluble impurities is not achieved. If the process time is more than 1.5 hours, this leads to unreasonably increased operating and capital costs. Continuous air supply to the pre-aeration tank 1 and the bioreactor 3 is carried out by the aeration system 8 through aeration elements, for example, membrane elements 9 with a middle bubble and small-bubble membrane elements 10 installed in the bottom of the preliminary aeration tank 1 and in the bottom of the bioreactor 3. membrane elements 9 with a middle bubble are installed in the preliminary aeration tank 1. In the bioreactor 3 in the anaerobic zones installed membrane elements 9 with a middle bubble, and in the aerobic zones installed membrane elements 10 with a small bubble.

From the pre-aeration tank 1, the effluent containing insoluble solids, dissolved organic compounds, as well as additionally dissolved organic compounds from insoluble solids, is fed for mechanical cleaning to device 2, where insoluble solids that do not contain adsorbed are extracted from the pre-treated runoff organics on them. Organics in the form of simpler easily digestible organic compounds, mainly in the form of volatile and fatty acids, are dissolved in wastewater. Mechanical treatment of wastewater containing insoluble impurities freed from organic matter adsorbed on them and activated sludge is preferably carried out by filtration on sieves with a mesh size of 2-5 mm. But it is also possible to use other well-known means - lattices, sieves, a drum with a net, etc.

Insoluble mechanical impurities freed from organic substances and trapped by mechanical device 2 are unloaded from it into containers and then sent to landfills, landfills - agreed places for storage, placement, processing. The specified precipitate is characterized by the absence of an unpleasant odor.

After the mechanical cleaning device 2, the effluent, free from insoluble impurities, containing activated sludge and easily digestible organic substances that additionally enter the solution, enters the bioreactor 3, where activated sludge from sump 4 is supplied in an amount of 90-95% of the total amount of recirculated activated sludge 7. The concentration of activated sludge in the bioreactor 3 is 2.5-7.5 kg / m ³ .

Bioreactor 3 is conditionally divided into zones alternating in oxygen concentration, which can be at least two in bioreactor 3 - anaerobic (a) and aerobic (b).

The oxygen concentration in the anaerobic zone of the bioreactor 3 is not more than 0.7 g O ₂ / m ³ in the aerobic zone is not less than 2.5 g O ₂ / m ³ .

The ratio of the volumes of anaerobic and aerobic zones in the bioreactor 3 is 1: 1, which ensures the biological treatment of wastewater with minimal formation of activated sludge while reducing operating costs.

The zones are not spatially separated from each other, but are conventionally distributed horizontally across the bioreactor 3. The number of zones depends on the contamination of the effluent entering the treatment. When the content in the wastewater entering the bioreactor 3, BOD5 is up to 150 mg O ₂ / dm ³ , the number of zones is 2. If the BOD5 is more than 150 mg O ₂ / dm ³ , then the number of zones is a multiple of two - 4, 6, 8 etc.

The alternation of the anaerobic (a) and aerobic (b) zones in the bioreactor 3 leads to an increase in the metabolism (metabolism) of microorganisms when they get into adverse conditions for them - from the anaerobic zone to aerobic and then from the aerobic zone to anaerobic, etc. In this case, bypassing the nitrification stage, nitrogen is removed from the effluent in the form of gaseous products N ₂ O ^↑ , N ₂ ^↑ . Organic matter is also excreted in the form of a gaseous product СО ₂ ^↑ (up to 92%). The amount of excess activated sludge formed is 0.028-0.052 kg / kg of removed BOD, which is the removal of activated sludge in the form of suspended solids in treated wastewater 3-8 mg / DM ³ .

Measurement of oxygen concentration is carried out by the electrochemical method (oximeters) or by the chemical method (Winkler method).

The actual oxygen content is automatically adjusted by adjusting the rotation of the blower motor with a frequency converter in accordance with the optimal oxygen concentration, by adjusting the air supply to the bioreactor zones through aeration elements.

After 6-8 hours, a mixture of wastewater with activated sludge leaves the bioreactor 3 and enters the sump 4, which is also conditionally divided into zones - aerobic (b) and anaerobic (a), in which the process of aerobic and anaerobic treatment is constantly carried out, i.e. e. biological treatment with activated sludge continues. Preferably 2/3 of the useful volume of the sump works as an aerobic zone, preferably 1/3 of the useful volume of the sump works as an anaerobic zone.

Then, in the sump 4, the mixture is separated - the clarified part is removed to discharge 11, and the settled activated sludge is constantly removed through pipelines 6 and 7 to the preliminary aeration tank 1 and to the bioreactor 3 (first anaerobic zone).

The rate of removal of settled activated sludge in the sump is selected taking into account maintaining a constant level of activated sludge in the sump 1/3 of its height and taking into account the creation of anaerobic conditions with an oxygen concentration of 0.1-0.3 g O ₂ / m ³ in the bottom of the sump.

The oxygen content at a depth of 1 m in the sump is 2-2.5 g O ₂ / m ³ , which ensures guaranteed treatment of wastewater from nitrogen compounds.

Pipelines 6.7 for recirculation of activated sludge into the preliminary aeration tank and the bioreactor are equipped with flow meters, for example, induction ones.

The automation process is carried out using well-known oxygen meters, liquid flow meters. As actuators use known frequency converters.

To confirm the effectiveness of the method, the test indicators are presented (table) of the proposed method for biological wastewater treatment at treatment plants with a capacity of 8000 m ^{3 /} day with six zones in the bioreactor, alternating in oxygen concentration from 0.3 g O ₂ / m ³ in the first zone - anaerobic up to 4.5 g O ₂ / m ³ in the sixth zone - aerobic.

Month BOD ₅ mg O ₂ / dm ³ COD mg O ₂ / DM ³ Ammonium nitrogen
mg N / dm ³ Phosphates mg R / dm ³ Nitrate nitrate mg N / dm ³ Bang substances mg / dm ³ entrance Exit entrance Exit entrance Exit entrance Exit Exit Exit January 372 3.2 651 38 35.04 0.25 10.0 0.36 5.03 8.9 February 526 3.6 1086 33 42.6 0.28 9.2 0.45 6.7 13.0 March 299 ≤3.0 699 29th 43.8 0.22 8.95 0.9 6.17 8.8 April 405 3.4 986 40 51.1 0.26 8.1 0.44 8.71 6.6 May 372 ≤3.0 718 28 35.1 0.28 7.53 0.41 3.2 8.3 June 312 ≤3.0 624 35 38.1 0.31 6.43 0.52 3.85 8.6 July 410 ≤3.0 768 36 41.6 0.28 7.8 0.46 5.1 6.0 August 364 ≤3.0 697 34 48.5 0.13 9.6 0.78 5,6 9.2 September 568 4.1 1037 38.5 42.9 0.29 8.8 0.48 6.1 9.8 October 518 ≤3.0 816 28 39.3 0.19 10.6 0.64 5.8 7.8 November 412 ≤3.0 726 32 41.2 0.16 11,2 0.43 4.2 9.6 December 268 ≤3.0 589 34 28.6 0.29 10.8 0.7 5.1 8.3 Note:
The concentration of activated sludge in the bioreactor - 6.5 g / DM ³
The volume of the removed excess activated sludge (t / year on dry matter) to be removed - 0

The inventive method allows for the creation of a closed ecosystem of wastewater treatment to automate the biological treatment process while reducing the technological load on the environment, by minimizing secondary pollution - excess activated sludge and harmful emissions into the environment, which leads to the absence of equipment for processing and storage of excess activated sludge, the lack of landfills for its disposal, reducing the consumption of reagents used in the treatment of sewage sludge, leading to secondary pollution.

Automation of the process eliminates the influence of the human factor in controlling the biological treatment process.

When using the proposed method is achieved:

- saving of land resources - when designing sewage treatment plants with a capacity of 25,000 m ³ / hour, the size of the sanitary protection zone was reduced from 450 m to 20 m (the project passed state examination in 2009 with a positive conclusion),

- solving the problem of odor - reducing emissions of unpleasant smelling substances in the air by removing sorbed organics from insoluble impurities,

- reduction of energy and operating costs due to the optimization of air flow, the lack of the need for secondary pollution and the use of expensive reagents.

- the method allows to exclude from the process the primary sump, which leads to a decrease in operating and capital costs for the construction of treatment facilities.

Claims (14)

1. A method of biological wastewater treatment, including treating wastewater in a bioreactor with zones alternating in oxygen content while supplying air to it, supplying treated wastewater to a sump, which also contains zones that are heterogeneous in oxygen content, where the biological treatment process with activated sludge continues, with the subsequent separation of the treated effluent and activated sludge and the return of activated sludge from the sump to the bioreactor, according to the invention, wastewater containing insoluble fur is initially treated organic impurities with organic substances sorbed on them, in the pre-aeration tank, to the entrance of which activated sludge is fed to decompose organic substances adsorbed on insoluble mechanical impurities, which in the form of easily assimilable organic substances go into solution, after the pre-aeration tank, wastewater, containing pure insoluble mechanical impurities, freed from organic substances sorbed on them, and activated sludge, go to mechanical cleaning to remove the indicated insoluble solids from the effluent, then the effluent containing activated sludge and easily digestible organic substances that have passed into the solution is fed into the bioreactor and then into the sump, from which the activated sludge is returned to the bioreactor and preliminary aeration tank with the formation of a closed waste water treatment cycle water 2. The method according to claim 1, characterized in that the level of wastewater in the pre-aeration tank is kept constant with continuous air supply. 3. The method according to claim 1, characterized in that the residence time of the mixture of wastewater and activated sludge in the pre-aeration tank is 45 minutes - 1.5 hours 4. The method according to claim 1, characterized in that the amount of activated sludge supplied from the sump to the pre-aeration tank is 5-10% of the total amount of recycled sludge. 5. The method according to claim 1, characterized in that the oxygen concentration of the water mixture in the pre-aeration tank is maintained at 2.5-3.5 g O ₂ / m ³ . 6. The method according to claim 1, characterized in that the bioreactor is conditionally divided into successively alternating zones with a heterogeneous oxygen content medium, the first of which is preferably anaerobic. 7. The method according to claim 1, characterized in that the number of zones in the activation tank is an even value - at least two. 8. The method according to claim 1, characterized in that the oxygen concentration in the anaerobic zone of the bioreactor is not more than 0.7 g O ₂ / m ³ . 9. The method according to claim 1, characterized in that the oxygen concentration in the aerobic zone of the bioreactor is at least 2.5 g O ₂ / m ³ . 10. The method according to claim 1, characterized in that the amount of activated sludge entering the bioreactor is 90-95% of the total amount of recycled activated sludge. 11. The method according to claim 1, characterized in that the concentration of activated sludge in the bioreactor is 2.5-7.5 g / DM ³ . 12. The method according to claim 1, characterized in that the ratio of the volumes of the anaerobic and aerobic zones in the bioreactor is 1: 1. 13. The method according to claim 1, characterized in that the mechanical treatment of wastewater containing insoluble impurities freed from organics adsorbed on them is preferably carried out by filtration, which is carried out on sieves with a mesh size of 2-5 mm sieves. 14. The method according to claim 1, characterized in that the concentration of oxygen in the water mixture in the bottom of the sump is 0.1-0.3 g O ₂ / m ³ and at a depth of 1 m in the sump - 2-2.5 g About ₂ / m ³ .

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