RU2433962C2 - Method and apparatus for aerobic biological treatment of waste water and compound organomineral fertiliser obtained based thereon - Google Patents

Abstract

FIELD: chemistry. ^ SUBSTANCE: invention relates to aerobic biological treatment of waste water and can be used in treatment plants of residential areas, agricultural and industrial companies. First, waste water is fed into a mechanical treatment device 1 for separation of solid residue, and then into a sand separator 2 and then further into a balancing tank 5 for balancing incoming waste water on concentration and water consumption. From the balancing tank 5, waste water is fed through a pipe 12 by a pump 32 into a primary settling tank 3. From the primary settling tank 3, waste water is fed through a pipe 13 into a biosorption tank 6. From the tank 6, waste water is fed through a pipe 14 into a biooxidation tank 7. Settling of the waste water and active sludge takes place in a secondary settling tank 4. Further, the treated waste water is fed into a post-treatment module 8 and then into a decontamination apparatus 9. The purified and decontaminated waste water is then output from the apparatus. Raw sludge and excess active sludge, separated after primary and secondary settling, are fed into an enzymatic-cavitational module 10 to obtain compound fertiliser. ^ EFFECT: invention increases efficiency and quality of treating waste water while simultaneously recycling raw sludge and active sludge by producing compound organomineral fertiliser therefrom. ^ 5 cl, 2 tbl, 1 dwg

Description

The invention relates to a method for aerobic biological wastewater treatment, installation for its implementation, as well as to complex organic-mineral fertilizer obtained on their basis, and can be used in wastewater treatment plants of settlements.

A known method of aerobic biological wastewater treatment, adopted as a prototype, comprising machining the source of wastewater and separating solid sediment from it, settling wastewater in the primary sump and separating raw sludge from it, aerobic biological wastewater treatment, settling wastewater mixture and activated sludge in the secondary sump, the withdrawal of precipitated activated sludge from the secondary sump, the supply of activated sludge to participate in the biochemical oxidation process and the removal of purified water (see description reference to the patent of the Russian Federation No. 2073648, IPC C02F 3/02 of January 11, 1995).

In the known method, wastewater treatment is carried out aerobically biological mainly activated sludge, which does not provide high rates of wastewater treatment.

The mixing of the suspension fed into the primary sump in the known method is preferably carried out pneumatically, namely by supplying air by means of a compressor with a pressure of 0.5 kg / m ² to realize the process of biochemical oxidation of organic pollutants in waste water. At a low installation height, suspensions are heated to a temperature of 60-70 ° C, at which the oxygen solubility decreases several times, and therefore, the process of biochemical oxidation of organic pollutants in wastewater is worsened.

The processing of excess activated sludge in the known method consists in the fact that it is, to one degree or another, subjected to intensive physical and mechanical action on the cells of microorganisms in order to stimulate the release of extracellular biopolymers by them.

For continuous isolation of biopolymers by microorganisms, the processing of activated sludge in a known method is carried out using cavitation exposure of high intensity. However, the cavitation effect of high intensity not only destroys pathogenic microbes, but also “kills all living things”, which reduces the efficiency of wastewater treatment.

In addition, the wastewater treatment process in a known manner takes a long time and limited volume due to the small height of the tanks.

The technical task of the invention is to increase the efficiency and quality of wastewater treatment with the simultaneous utilization of raw and activated sludge by obtaining complex organic mineral fertilizers from them.

The technical problem is achieved in that the method for aerobic biological wastewater treatment includes mechanical treatment of wastewater and separation of solid sediment from it, sedimentation of wastewater in the primary settler and separation of crude sediment from the primary settler, aerobic biological treatment, settling of wastewater and activated sludge secondary sump, the removal of excess activated sludge from the secondary sump and the discharge of treated wastewater, while the wastewater, before being fed to the primary settling, is averaged over concentration and water consumption and then clarified wastewater is fed to biological treatment and biooxidation, which are carried out in a circulation mode for 2-3 hours, then to secondary sedimentation, tertiary treatment and disinfection, and crude sludge and excess activated sludge recovered after primary and secondary sedimentation, sent to a joint enzyme-cavitation treatment to obtain complex fertilizer, while the sludge mixture is pre-activated by low-intensity cavitation for 2-3 seconds, during pumping and processing, and saturated with oxygen up to 8-10 mg / L during pumping for forming bacteria and in the operating mode for 4-6 hours bacterial activation of the mixed liquor are continuously low intensity cavitation, at a pressure of more than 1 kg / m ^2, and the oxygen concentration is maintained in the range of 10-20 mg / l, while the bacterial activation of the sludge mixture is accompanied by the release of heat necessary for the process and the formation of enzymes that are protein catalysts of the process, as well as derivatives of enzymes that form chelate compounds neniya. The treatment of the sludge mixture of crude sludge and excess activated sludge is carried out together in a ratio of 1: 3 in terms of the concentration of dry matter.

The proposed method allows for 4-6 hours on one installation to purify wastewater, increasing the efficiency of purification, to improve the quality of treated wastewater and at the same time to obtain complex organic-mineral fertilizer by combined enzyme-cavitation treatment of raw and activated sludge.

The constant bacterial activation of the sludge mixture in the operating mode by cavitation of low intensity at a pressure of more than 1 kg / m ² to a height of more than 10 m with constant stirring with air does not cause heating of the sludge mixture. The process is carried out in significant volumes with the release of heat necessary for the process of processing the sludge mixture, accompanied by the formation of enzymes that are protein catalysts of the process.

Dehydration of the obtained product in geotextile containers does not require additional costs for the construction of plants for dehydration, which reduces the cost of the method.

These circumstances indicate that the claimed technical solution meets the criterion of "novelty."

A comparison of the claimed method with the known one shows that it does not follow explicitly from the prior art for a specialist, which indicates that the claimed technical solution meets the criterion of "inventive step".

The proposed method is implemented as follows.

Initially, the wastewater is sent for treatment to trap and grind solid waste (rags, rags, chips, etc.) into a homogeneous mass, and then the release of heavy impurities of mineral origin, mainly sand. Then, the wastewater is fed to the averaging of the incoming wastewater, both in concentration and in the water flow rate and then to the primary sedimentation, while undergoing preliminary treatment with low intensity cavitation, namely the saturation of the wastewater with atmospheric oxygen.

During initial settling for 1-1.5 hours, coarse and fine impurities are released from wastewater, which, under the influence of gravitational force in a downward-upward flow during sequential thin-layer separation, settle to the bottom of the primary sedimentation module or float to its surface.

Having passed the process of primary sedimentation, the wastewater enters bisorption, recycled activated sludge is also fed there after the secondary sedimentation of wastewater. In the process of biosorption, which takes place in the circulation mode for 2-3 hours, the wastewater is constantly saturated with oxygen of finely dispersed air, which is necessary for the life of microorganisms and the oxidation of organic substances. The biosorption process is carried out with constant stirring with air, eliminating the compaction of sludge and the formation of secondary pollution. The biosorption process is accompanied by the formation of the following species composition of microorganism groups: Achromobacter, Alcaligenes, Gordonia, Microtix, Fusdarium, Aquaeductum, Bodo globusus.

Further, the wastewater enters the biooxidation, where complex processes of nitrification and denitrification of wastewater take place in the circulation mode for 2-3 hours. At the biooxidation stage, new groups are added to the microorganisms: Sphaerotilus natans, Baggiatoa alba, Acinetobacter, Vorticella convallaria, Zoogloeo ramigera, Opercularia, Flavobacterium, Carhesium, Rotifera, Micrococcus, Bodo edax, Nitrobila and others.

After the biooxidation process, the wastewater is fed to secondary sedimentation, where activated sludge is precipitated within 1-1.5 hours.

Next, the wastewater is directed for 1-1.5 hours for purification by biofiltration, then it is disinfected, for example, using sodium hypochlorite, ultraviolet disinfection, ozonation, electro-pulse or catalytic exposure, and then the treated and neutralized wastewater is discharged.

The crude residue formed during the initial sedimentation, as well as excess sludge after secondary sedimentation and after the wastewater aftertreatment, is fed to the enzyme-cavitation treatment. The sludge mixture is pre-activated by low-intensity cavitation for 2-3 seconds, during pumping it for processing, and saturated during pumping with oxygen up to 8-10 mg / l for the formation of bacteria.

In the operating mode of enzyme-cavitation treatment, bacterial activation of the sludge mixture is carried out for 4-6 hours by low-intensity cavitation constantly with an oxygen concentration in the range of 10-20 mg / l. The process of processing the sludge mixture is carried out at a pressure of more than 1 kg / m ² with the release of heat necessary for the processing of the mixture of sludge, accompanied by the formation of enzymes that are protein catalysts of the process, and derivatives of enzymes that form chelate compounds necessary for the conversion of salts of heavy metals in a natural safe state.

After completion of the process of enzyme-cavitation treatment of the sludge mixture, the obtained product, with a moisture content of 98-98.5%, is sent for further dehydration to geotextile containers, which are transported to the destination, and supra water after the process of enzyme-cavitation treatment is used in the biosorption process.

A known installation of biological wastewater treatment, adopted as a prototype, containing a device for machining wastewater for separating solid sludge, a primary settler, a secondary settler, a device for removing and supplying sludge, a device for supplying and discharging wastewater and treated wastewater, an aeration tank, a device physical and mechanical processing, mixing devices (see the description of the patent of the Russian Federation No. 2073648, IPC C02F 3/02 of January 11, 1995).

The disadvantages of the known installation are the low cleaning efficiency and the quality of wastewater treatment.

In addition, the known installation is characterized by low productivity due to the limited height of the tanks, which reduces the volume of wastewater processed and increases the time of wastewater treatment due to the low intensity of treatment.

The technical task of the invention is to increase the efficiency and quality of wastewater treatment with the simultaneous utilization of raw and activated sludge by obtaining complex organic mineral fertilizers from them.

The technical problem is solved in that the installation for aerobic biological wastewater treatment contains a device for the mechanical treatment of wastewater for separating solid sludge, a primary sump, a secondary sump, a device for withdrawing and supplying sludge, a device for supplying and discharging waste water and purified water, an aerotank, a device physical and mechanical processing, mixing devices, while it is additionally equipped with a homogenizing tank, a post-treatment module, a disinfecting wastewater installation, and also dehydrate a module and an enzyme-cavitation module for the joint processing of sludge, a primary settler, a secondary settler, an aeration tank made in the form of two interconnected autonomous containers for biosorption and biooxidation, an enzyme-cavitation module and a post-treatment module made in the form of vertically mounted tower towers with a height over 10 m with forced supply of wastewater and sludge, the averaging tank is connected to the primary sump, the primary sump is connected to the biosorption tank, the biooxidation tank is connected to a secondary sump, a primary sump, a secondary sump and a post-treatment module are connected to an enzyme-cavitation module connected to a dehydrator, and a decontamination unit is installed at the outlet of the post-treatment module, while the sludge supply device to the enzyme-cavitation module and wastewater in the biosorption and biooxidation tanks in the form of pipelines equipped at the points of connection with containers with devices for oxygen saturation of the air, and pumps, on the suction line of which there are devices for creating Cavitation of low intensity, and in the lower part of the enzyme-cavitation module and the biosorption and biooxidation tanks, mixing devices are installed made in the form of turbulators to prevent active sludge from settling and to ensure mixing to the height of the module tanks.

The disinfection unit is designed as a biofilter.

The installation in the form of vertically mounted tank towers with a height of more than 10 m, can significantly increase its productivity and reduce the installation area.

The implementation of the mixing devices in the form of turbulators with an air supply at a pressure of 1 kg / m ² ensures the mixing of the sludge mixture to the entire installation height and prevents the temperature increase, increases the efficiency of the process and reduces the time for cleaning.

The use of geotextile containers for dewatering the treated sludge simplifies and reduces the cost of installation by eliminating the need for installations for this purpose.

These circumstances indicate that the claimed technical solution meets the criterion of "novelty."

A comparison of the proposed installation with a known one shows that it does not follow explicitly from the prior art for a specialist, which indicates that the claimed technical solution meets the criterion of "inventive step".

The drawing shows a diagram of the proposed installation for aerobic biological wastewater treatment and complex organic-mineral fertilizers.

The installation contains a device 1 for mechanical treatment of wastewater for separating solid sludge and a device for separating sand 2, a primary settler 3, a secondary settler 4. In addition, it is additionally equipped with a homogenizing tank 5, aeration tank made in the form of two autonomous containers 6 and 7 for biosorption and biooxidation, respectively, by a post-treatment module 8, a wastewater disinfection unit 9, installed at the outlet of a post-treatment module 8, an enzyme-cavitation module 10 and a sludge mixture dehydrator 11.

The primary sump 3, the secondary sump 4, tanks 6 and 7 for biosorption and biooxidation, the enzyme-cavitation module 10 and the post-treatment module 8 are made in the form of vertically installed tank towers with a height of over 10 m with forced supply of sewage and sludge.

The averaging tank 5 is connected by a pipe 12 to the primary sump 3, the primary sump 3 is connected by a pipe 13 to a biosorption tank 6, the biosorption tank 6 is connected to a biooxidation tank 7 by a pipe 14, the biooxidation tank 7 is connected by a pipe 15 to a secondary sump 4. Secondary the sump is connected by a pipe 16 to a post-treatment module 8, the output of which is connected by a pipe 17 to a disinfection unit 9.

The primary sump 3, the secondary sump 4 and the aftertreatment module 8 are connected by a pipe 18 to an enzyme-cavitation module 10, and the enzyme-cavitation module 10 is connected by a pipe 19 to a sludge mixture dehydrator 11 made in the form of a geotextile container.

The supply of sludge to the enzyme-cavitation module 10 and wastewater in the tanks 6 and 7 for biosorption and biooxidation is carried out by pumps 20, 21 and 22 through pipelines 23, 24 and 25, respectively, at the junction with the tanks of which are installed devices for oxygen saturation of air 26, and on the suction line of the pumps 20, 21, and 22, devices for creating cavitation of low intensity (devices for creating cavitation of low intensity are not shown in the drawing).

In the lower part of the enzyme-cavitation module 10 and tanks 6 and 7 for biosorption and biooxidation, mixing devices 27 are installed, made in the form of turbulators to prevent sedimentation of activated sludge and to ensure mixing to the height of the enzyme-cavitation module 10 and tanks 6 and 7 for biosorption and biooxidation.

To ensure the circulation mode, the tanks 6 and 7 are equipped with an input 28 in the upper part and an output 29 in the lower part, connected by a pipeline to the pipeline 18.

The enzyme-cavitation module 10 in the upper part is equipped with an outlet 30, and in the lower outlet 31, connected to the pipe 19 for the output of sludge mixture and superficial water, respectively.

The supply of waste water to the primary sump 3 is carried out by the pump 32.

Wastewater from tanks 6 and 7 to the averaging tank 5 is, if necessary, carried out through pipeline 33, and from dehydrator 11 through pipeline 34.

At the intersection of the pipelines 18, 19 and 34, switching devices 35 are installed.

Installation works as follows.

Initially, the wastewater enters the wastewater machining device 1, which is designed to trap and grind solid waste (rags, rags, chips, etc.) into a homogeneous mass, where heavy impurities of mineral origin are released, and then to the sand separator 2 and further - to the averaging tank 5 for averaging the incoming wastewater both in concentration and in water flow.

From the averaging tank 5, the wastewater is pumped through a pipe 12 to a primary settler 3 through a pipe 12. The device on the suction line of the pump 32 creates cavitation of low intensity, providing coarse-dispersed and fine impurities from the wastewater, which under the influence of gravitational force in a downward-upward flow successive thin-layer separation settle to the bottom of the primary sedimentation module 3 or float to the surface.

From the primary sump 3, the wastewater flows through a pipe 13 to a bisorption tank 6, while the pump 20 provides a circulation mode in which the wastewater is saturated with atmospheric oxygen, the supply of which is provided by the device 26 installed on the pipe 24, and the mixing device 27.

From the tank 6, the wastewater through the pipeline 14 enters the tank 7 for biooxidation, while the pump 21 provides a circulation mode in which the wastewater is saturated with atmospheric oxygen, the supply of which is provided by the device 26 installed on the pipeline 24, and the mixing device 27. biooxidation, the wastewater enters the post-treatment module 8 and then through the pipe 17 to the disinfection unit 9, then the purified and disinfected wastewater is discharged from the unit.

The crude residue formed in the primary 3, as well as excess sludge after from the secondary sump 4 and after the aftertreatment module 8, in a ratio of 1: 3 in terms of dry matter concentration, is pumped through a pipe 18 to the enzyme-cavitation module 10, at This sludge mixture during pumping it to the processing is pre-activated by cavitation of low intensity for 2-3 seconds and saturated during pumping with oxygen up to 8-10 mg / l for the formation of bacteria.

In the operating mode of enzyme-cavitation treatment, bacterial activation of the sludge mixture is carried out for 4-6 hours by low-intensity cavitation continuously with an oxygen concentration in the range of 10-20 mg / l at a pressure of more than 1 kg / m ² .

After the completion of the process, the obtained product with a moisture content of 98-98.5% from the enzyme-cavitation module 10 through the outlet 30 through the pipeline 19 is sent for further dewatering in geotextile containers 11, which are transported to the destination, and supra water through the outlet 31 is fed through the pipeline 34 into the averaging tank 5.

Known fertilizer containing sludge obtained during biological wastewater treatment (see the description of the patent of the Russian Federation No. 2316523, IPC C05D 9/00, C05F 3/00, C05F 7/00, C05F 9/04 from 09/21/2006).

A disadvantage of the known fertilizer is the presence of a significant amount of an organic component in the form of manure. When using a well-known fertilizer, the soil degrades already in the first year, and the presence of pathogenic microflora negatively affects the final product.

The technical task of the invention is to increase the efficiency and quality of wastewater treatment with the simultaneous utilization of raw and activated sludge to obtain complex organic mineral fertilizer from them.

The technical problem is achieved in that the complex fertilizer contains sludge obtained during biological wastewater treatment, while a mixture of crude sludge and excess activated sludge recovered after primary, secondary sedimentation and post-treatment, taken at a ratio of components, wt. %:

activated sludge 60-80 crude sediment 40-20

The proposed complex fertilizer has a peat-like structure, which contributes to the preservation of the optimum amount of moisture, as well as the suppression of weed growth and the multiplication of pests due to high adsorption forces in the radius of the stem of the growing culture.

Chelated compounds formed during the enzyme-cavitation treatment of the sludge mixture allow the conversion of heavy metal salts to a natural safe state.

In addition, chelate compounds retain various forms of water, for example, by withdrawing it from morning dew from the earth's surface, as well as in the form of capillary and hygroscopic water from an underground environment, which makes it possible to use the proposed complex fertilizer in arid regions.

Organic substances make up over 20%, total nitrogen 2.54%, phosphorus 4.2%, and the amount of potassium 1.25% and others. Depends on the composition of the source wastewater.

Complex fertilizer is prepared as follows.

The crude residue formed during the initial sedimentation of wastewater, as well as excess sludge after its secondary sedimentation and after tertiary treatment of wastewater in an amount of 40-20 wt.% Of the crude residue and 60-80 wt.% Is fed to the enzyme-cavitation treatment, while sludge the mixture during pumping it for processing is pre-activated by low-intensity cavitation for 2-3 seconds and saturated with oxygen up to 8-10 mg / l for the formation of bacteria.

In the operating mode of enzyme-cavitation treatment, bacterial activation of the sludge mixture for 4-6 hours is carried out by low-intensity cavitation constantly with an oxygen concentration in the range of 10-20 mg / l.

The process of processing the sludge mixture occurs at a pressure of more than 1 kg / m ² with the release of heat necessary for the processing of the mixture of sludge. The process of enzyme-cavitation treatment is accompanied by the formation of enzymes, which are protein catalysts of the process, and derivatives of enzymes. Derivatives of the enzymes form chelate compounds that convert heavy metal salts to their natural state.

After completion of the process of enzyme-cavitation treatment of the sludge mixture of wastewater, the resulting product is sent for dewatering in geotextile containers that are transported to the destination.

Complex fertilizer was applied to the soil before sowing wheat, corn and potatoes with a dose of 20 t / ha, 20 t / ha and 15 t / ha, respectively. The results showed that the proposed complex fertilizer provides an increase in wheat productivity in drought conditions, namely, the complete absence of natural or artificial irrigation on light chestnut soils from 0.58 t / ha of non-fertilized (control) plot to 4.86 t / ha of fertilized plot, t. e. 8.38 times.

The yield of maize on light chestnut soils during drought, as compared with the control plot, was increased in the phytomass from 5.52 t / ha to 54.3 t / ha without irrigation. Potato productivity doubled from 20 t / ha to 40 t / ha, while the amount of water supplied for irrigation was halved. Data on the use of complex fertilizers are summarized in the table.

When studying the application of complex fertilizer to the soil many times, it turned out that its fertilizing ability did not decrease for 5-6 years, in addition, during this time weed and pest growth was suppressed, annual regeneration and additional costs for weed and pest control were not required. Significantly reduced the amount of water for irrigation.

When comparing complex fertilizer with a prototype, the required amount of which is 5 t / ha, at a cost of one ton of 2000 rubles. and its annual regeneration, the effectiveness of the proposed complex fertilizer is much higher, namely, the cost of complex fertilizer is 4 times cheaper. In addition, complex fertilizer is obtained from sludge waste, releasing significant areas of land from pollution.

The environmental damage from fertilizing with quartz-glauconite sand is obvious, as its mining is required, as a result of which quarrying is necessary.

Table 1 Structure The total humidity of the mixture,% Unit mg / kg Unit of measurement, % fertilizer offered activated sludge 75 60 25 crude sediment containing, including: - N nitrogen total more than 1.4 - P phosphorus total more than 2.7 - O ₂ oxygen more than 10 fertilizer prototype: - quartz-glauconite sand 60 25 - manure fifteen - silt sediment 35 containing, including: 2.54 - N nitrogen total 4.2 - R phosphorus total

table 2 Options Crop structure by crops, t / ha wheat potatoes corn phytomass one Soil without fertilizer 0.58 twenty 5.52 2 Soil + fertilizer prototype 4.62 32,4 53.59 3 Soil + fertilizer offered 4.86 40 54.30

Claims (4)

1. A method for aerobic biological wastewater treatment, comprising mechanically treating the source water and separating solid sediment from it, settling the wastewater in the primary sump and separating the raw sludge from the primary sump, aerobic biological treatment, settling the wastewater and activated sludge in the secondary sump, the withdrawal of excess activated sludge from the secondary sump and the removal of purified water, characterized in that the wastewater before being fed to the primary sedimentation is averaged over the concentration and flow rate of water, and then the clarified wastewater is fed to biological treatment and biooxidation, which are carried out in a circulation mode for 2-3 hours, then to secondary sedimentation, tertiary treatment and disinfection, and the crude sludge and excess activated sludge recovered after primary and secondary sedimentation are sent to a joint enzyme-cavitation treatment to obtain complex fertilizer, while the sludge mixture is pre-activated by low-intensity cavitation for 2-3 s during pumping it to the treatment and saturated with oxygen to 8-10 mg / l during pumping for the formation of bacteria, and in the operating mode for 4-6 hours, bacterial activation of the sludge mixture is carried out by low-intensity cavitation constantly at a pressure of more than 1 kg / m ² , and the oxygen concentration is maintained within 10-20 mg / l, while the bacterial activation of the sludge mixture is accompanied by the release of heat necessary for the process and the formation of enzymes that are protein catalysts of the process, as well as derivative enzymes that form chelate compounds. 2. Installation for aerobic biological wastewater treatment, containing a mechanical wastewater treatment device for separating solid sludge, a primary sump, a secondary sump, a device for withdrawing and supplying sludge, a device for supplying and discharging wastewater and treated wastewater, an aerotank, a physical machining, mixing devices, characterized in that it is additionally equipped with a homogenizing tank, a post-treatment module, a disinfecting wastewater installation, as well as a dehydrator and a farm ntn-cavitation module for the joint processing of sludge, primary sedimentation tank, secondary sedimentation tank, aeration tank made in the form of two interconnected autonomous containers for biosorption and biooxidation, the enzyme-cavitation module and the aftertreatment module are made in the form of vertically mounted tower containers with a height of over 10 m with forced supply of wastewater and sludge, the averaging tank is connected to the primary sump, the primary sump is connected to the biosorption tank, the biooxidation tank is connected to the secondary a sump, a primary sump, a secondary sump and a post-treatment module are connected to an enzyme-cavitation module connected to a dehydrator, and a decontamination unit is installed at the outlet of the post-treatment module, while the sludge supply device to the enzyme-cavitation module and wastewater in a biosorption and biooxidation tank in the form of pipelines equipped at the points of connection with containers with devices for oxygen saturation of the air, and pumps, on the suction line of which devices for creating cavit are installed low intensity, and in the lower part of the enzyme-cavitation module and biosorption and biooxidation tanks, mixing devices are installed made in the form of turbulators to prevent sedimentation of activated sludge and to ensure mixing to the height of the module tanks. 3. Installation according to claim 3, characterized in that the disinfecting installation is made in the form of a biofilter. 4. Complex organic-mineral fertilizer containing sludge obtained during biological wastewater treatment, characterized in that a mixture of crude sludge and excess activated sludge recovered after primary, secondary sedimentation and post-treatment, taken at a ratio of components, wt. %:
activated sludge 60-80 crude sediment 20-40