RU2475458C2 - Treatment of effluents to produce purified water and decontaminated wastes - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to biological treatment of whatever effluents and may be used in municipal utilities, industrial complexes. Proposed method comprises filtering the effluents in screens, mechanical cleaning in sand catchers, flushing, compacting and drying wastes of screens and sand catchers, balancing effluents flows according to daily schedule, biological treatment in step bioreactors of denitrification with circulation of active silt and biocenoses, additional treatment in filtration units with fibrous wire-brush bed, granular anthracite and proportioning of reagents for bonding phosphates into insoluble matters and trapping insoluble suspended matters, separation of return and active slit in secondary thin-bed settles, treating active slit by reagents and dewatering jointly with sediment extracted from additional treatment waters, decontamination of said waters by UV rays, drying and decontamination of dehydrated sediments. Vent air from mechanical treatment facilities is forced to the stage of high-rate aerobic biological treatment by cenosis of organic hereotrophs secured at said metal-wire bed and, thereafter jointly with free active slit separated in bioreactors of denitrification, into nitrification reactors, while used air from the latter is forced through the system electrocatalytic decontamination units into ambient air prior release into decontaminated air discharge system. Wastes dried at 240°C to moisture content of 25%, decontaminated and cooled to 40°C are packed in sealed bags and carried to storehouses or disposal sites.

EFFECT: improved environmental protection.

2 dwg

Description

The invention relates to methods for biological treatment of domestic and industrial wastewater and can be used in municipal services of cities, industrial complexes.

It is known to use three-strand biological water treatment [Method of three-strand biological wastewater treatment. Patent for invention No. 2264353, published November 20, 2005, Bull. Number 32. Patent holder Kulikov NI] by communities of heterotrophic bacteria attached to a fiber brush nozzle, which provides intensive cleaning processes by microbial communities specialized in cleaning stages. In the known device, no attention was paid to reducing emissions of harmful substances emitted during the treatment of wastewater into the environment (both into the air basin and to the surface of the earth with emitted wastes and sediments, hygiene and sanitation of the treatment plant attendants).

The closest by the greatest number of similar essential features, the achieved effect of wastewater treatment, including from nutrients, by the modularity of blocking of individual units, the completeness of equipment, the compactness of the treatment plant, and the creation of favorable conditions for staff in hygiene and labor protection modular treatment plant [Complete modular treatment plant. Patent for invention No. 2343122, published January 10, 2009, Bull. No. 1. Patent holder Kulikov N.I.].

Unfortunately, in the well-known treatment plant, zero emission of waste into the environment is not achieved; therefore, such a station cannot be built directly in residential buildings in order to create the possibility of widespread use of purified and disinfected water for technical water supply, for example, toilets in residential buildings, for street irrigation , green spaces in low-water regions with a hot climate, or to reduce the length of sewer network pipelines in coastal settlements, for example, the Greater Sochi region.

The objective of the invention is to achieve a zero balance of waste from the sewage treatment plant into the environment, reduce the amount of air used at the sewage treatment plant for the wastewater treatment process, reduce the land area under the sewage treatment plant, improve the working conditions of staff, reduce the width of the sanitary protection zone around the sewage treatment plant stations, creating an architectural appearance for a treatment plant suitable for placement of a treatment plant in residential buildings.

The tasks are solved in that a method of treating wastewater to produce purified water and neutralized waste, including filtering wastewater in grates, mechanical cleaning in sand traps, washing, pressing and drying waste from grates and sand traps, equalizing wastewater costs by the hours of the day due to cost averagers, biological wastewater treatment in step nitri-denitrification bioreactors with recirculation of activated sludge and biocenoses attached to a fiber brush nozzle, wastewater treatment d in filtration devices with a fiber ruffled nozzle, granular anthracite and dosing of reagents for binding phosphates to insoluble substances and trapping insoluble suspended solids on them, recovery of return and excess activated sludge in secondary thin-layer settlers, reactive treatment of activated sludge and dewatering together with sediment recovered from regeneration and washing waters of post-treatment, disinfection of treated water by irradiation with ultraviolet rays. In this case, ventilation air from mechanical wastewater treatment plants is supplied by blowers to the stage of high-speed aerobic biological wastewater treatment by a community of organo-heterotrophs attached to a brush nozzle and as part of free-floating activated sludge; the exhaust air released from the denitrification bioreactors by another group of blowers is pumped into the nitrification bioreactors, and the exhaust air released from the nitrification bioreactors is passed through a system of electrocatalytic disinfection and neutralization devices before being discharged into the dispersing system to remove neutralized air into the surrounding air; dried by the conductive method at a temperature of 240 ° C to a moisture content of 25% and disinfected waste from wastes and sewage sludge after cooling to 40 ° C are packed and packaged in sealed block bags for transportation to storage or disposal sites, ensuring zero emission of waste from the treatment plant in the natural environment and reducing the width of the sanitary protection zone around the treatment plant to the width of the transport line.

An analysis of the known technical solutions related to methods of wastewater treatment and treatment of the allocated waste from sewage treatment plants showed that technical solutions containing the same set of essential solutions containing the same set of essential features as the claimed method were not found. This allows us to conclude that the claimed method meets the criterion of "novelty."

Analysis of the identified significant features distinctive from the prototype showed that such or similar features in known technical solutions with the manifestation of the same properties were not found, which allows us to conclude that the claimed method meets the criterion of "significant differences".

The claimed combination of essential features allows you to get a new, higher result, expressed by the deep disposal of waste treatment plant with a reduction in the volume of capacitive structures and the amount of harmless air removed. Removable sewage sludge is odorless, compact and does not affect humans and the environment.

The method is illustrated by the technological scheme of wastewater treatment and treatment of waste generated during wastewater treatment (Figure 1), as well as the appearance of the treatment plant (Figure 2).

The list of positions of the technological scheme of wastewater treatment and treatment of waste generated during wastewater treatment (Figure 1).

1. The flow of source wastewater;

2. The receiving chamber;

3. Lattices; 3 ^' . Garbage from grates;

4. Sand traps; 4 ^' . Sand trap from sand traps;

5. Tanks of averagers of wastewater costs;

6. Node mechanical wastewater treatment;

7. Blowers; 7 ^' . Air for supplying oxygen to the denitrifiers 11;

8. Node biological wastewater treatment;

9. The device dewatering waste 3 ^' from the grids 3;

10. A device for washing and dehydrating sand pulp 4 ^' from sand traps 4;

11. Denitrifiers for biological wastewater treatment heavily loaded with organic impurities, closed on top with caps 14;

12. Nitrification;

13. Cassettes with a fiber ruffled nozzle for holding biomass of attached microorganisms;

14. Caps on denitrification 11 and nitrification 12;

15. Blowers for supplying air through pipelines 15 ^' from under the caps 14 to the nitrifiers 12;

16. Pumps for supplying sewage through pressure pipelines 16 ^' from averagers 5 to denitrifiers 11;

17. Secondary thin-layer sedimentation tanks;

18. Node of wastewater treatment;

19. Pumps for the supply of return and excess activated sludge; 19 ^' . Return activated sludge pipelines;

20. Pipelines of excess activated sludge;

21. The site of thickening and dehydration of excess activated sludge;

22. Gravity slugger;

23. Screw pump compacted sludge;

24. A dewatering device;

25. A pump installation of superficial water and a centrate from a dewatering device 24;

26. An intermediate silo of dehydrated sludge;

27. Screw conveyor;

28. Paddle dryer;

29. The cooling installation of the dried precipitate;

30. Packing and packaging unit;

31. Reagent farm for the removal of phosphates and dehydration of sediments;

32. Installation of irradiation of treated water with ultraviolet rays;

33. Discharge pipelines of treated and disinfected water to a pumping station for technical water supply.

34. A fan for supplying exhaust air to the assembly 35;

35. The site of disposal and disinfection;

36. Prefilter;

37. Gas discharge processing unit;

38. The catalytic decomposition unit of excess ozone.

The flow of source wastewater 1 enters the sewage treatment plant (WWTP), into the receiving chamber 2, from which it is distributed to the grates 3, sand traps 4 and then to the tanks 5 of the cost averagers. Buildings 2, 3, 4, 5 relate to the unit 6 of mechanical wastewater treatment. The unit 6 is equipped with a forced ventilation system, the air for which is taken outside the boundaries of the WWTP enclosing the surfaces, and is discharged from the inside of the unit 6 to the inlet of the blowers 7 of the biological wastewater treatment unit 8. Inside the mechanical cleaning unit 6 are located: a device 9 for dewatering waste 3 ^' from the grates and a device 10 for washing and dewatering the sand pulp 4 ^' from the sand traps. From the averagers 5, the wastewater by gravity and through the pumps 16 through the pressure pipe 16 'is fed to the biological wastewater treatment unit 8, including denitrifiers 11 and nitrificators 12. An intensive high-speed biological wastewater treatment from organic impurities takes place in denitrifiers 11 through the activity of organo-heterotrophic microorganisms, held on cartridges 13 by a fibrous, ruffled nozzle and as part of a free-floating activated sludge circulating inside the biological assembly 8 Cleaning the waste water from the denitrifying bacteria to secondary clarifiers 17 and thin back. The vital activity of organo-heterotrophs is ensured by introducing air oxygen and nitrate denitrifiers into the sludge mixture together with return activated sludge, and the mass transfer between microorganism cells and wastewater creates air flows from aeration bubblers located on the bottom of both denitrification tanks and nitrification tanks 12. However, reservoirs Denitrifiers 11 are provided with air through the air ducts 7 ^' from the blowers 7, which take air from the ventilation stream of the mechanical cleaning unit 6. This air contains odorous substances, and organoheterotrophs absorb these substances from the air and oxidize them to carbon dioxide.

Air for nitrification 12 is supplied by blowers 15 through air ducts 15 ', and these blowers take air from under the caps 14, which are closed on top of denitrification tanks 11. The air passing through denitrifiers 11 is 2% depleted in oxygen, but enriched in carbon dioxide. In atmospheric air, up to 20% of the composition of the air is oxygen, and the rest is nitrogen.

After oxygen denitrifiers in used air, not more than 18% by weight, but carbon dioxide weighing up to 1% by weight of air is added to nitrogen and oxygen. The presence of carbon dioxide in the air coming from aeration bubblers to nitrification 12 accelerates by 20 ... 30% the rate of nitrogen oxidation by ammonia by the biocenosis of autotrophs held in nitrification on a fibrous, brush nozzle of cartridges 13, and as part of free-floating activated sludge. From nitrifiers 12, the sludge mixture with wastewater enters the secondary thin-layer settlers 17, where it is divided into two streams. The first stream - the stream of clarified wastewater by gravity is directed to the wastewater treatment unit 18, and the second stream - stream with a high content of free-floating sludge is pumped by pumps 19 through pipelines 19 'to denitrifiers 11, and through pipelines 20 it is fed to the unit 21 for thickening and dehydrating excess active silt. Node 21 includes a gravity sludge compactor 22 to bring sludge moisture to 98% with an initial moisture content of 99.6%, then compacted sludge with screw pumps 23 is pumped to a mechanical dewatering device 24 (centrifuge, or filter press, or screw dehydrator) with reagent flocculation and sludge humidity decreases to the level of 80-83%. Sludge water from the gravity sludge compactor 22 and dewatering device 24 is returned to the denitrifiers 11 with a special pumping unit 25. Dehydrated sludge is accumulated in the intermediate hopper 26, from which the sludge is metered into the paddle dryer 28 using a screw conveyor 27. The sludge is dried using a conductive method at a temperature of 240 ° C. After drying, the precipitate with a moisture content of 25% in the form of a powder enters the cooling unit 29, where its temperature drops to 40 ° C. After cooling, the sludge enters the packing and packaging unit 30. The sludge packed in sealed block packages is transported to storage or disposal sites.

Garbage from gratings and sludge from sand traps from unit 6 for mechanical wastewater treatment are subjected to a separate stream in a similar stream to drying and packaging.

The air exiting from the caps 14 of the nitrifying 12, is taken in by the fans 34 of the exhaust air supply to the neutralization and disinfection unit 35 before being discharged outside the WWTP into the surrounding air pool. First, the prefiltration unit 36 stands in the way of the exhaust air. The filters of this unit are designed to clean the air from dust and, in part, aerosols and consists of cartridges with pocket filters.

The main process of air purification is carried out in gas discharge unit 37, in the so-called “cold” plasma, in a low-temperature plasma with the formation of ozone from atmospheric oxygen and subsequent oxidation and disinfection of microbial and viral aerosols and organic substances by ozone. The process of air treatment in the catalytic unit 38 is completed, in which excess ozone is decomposed with the help of a catalyst and the air is freed of residual impurities before being discharged into the surrounding WWTP air.

The wastewater aftertreatment unit 18 includes two-stage filtration, first through a filter charge from cassettes 13 with a fibrous, ruffled nozzle, and then through a charge from granular anthracite. Wash and regeneration water from the wastewater treatment unit 18 is discharged to gravity sludge compactors 22, where they are freed from suspended solids and, together with superfluous water, from the activated sludge are returned to the denitrifiers 11. To ensure the removal of phosphates from wastewater into the treated wastewater before it is introduced into an aftertreatment filter with a granular charge of anthracite is added with a reagent containing aluminum or iron prepared in a reagent farm 31. The resulting water-insoluble phosphates of iron or aluminum they are retained in the anthracite load without crumpling it, since during washing they are easily separated from the anthracite grains and removed with washing water. The treated wastewater after the post-treatment unit 18 is sent to the ultraviolet irradiation unit 32 and then discharged through pipelines 33 to the pumping station for technical water supply for use in the municipal utilities of the city or industrial enterprises.

The above scheme works as follows. Wastewater stream 1 flows into the receiving chamber 2 and then distributed to the working grate 3 for filtering and allocation of waste 3 ^' with a particle size of more than 5 mm. After the gratings 3, the wastewater is settled in sand traps 4 to isolate heavy particles such as sand with a hydraulic particle size of more than 15 mm / s. Peskopulpa 4 ^' and garbage 3 ^' from the grids of the mechanical wastewater treatment unit 6 are dehydrated, respectively, the garbage 3 ^' from the grids 3 in the device 9, and the sand pulp 4 ^' from the sand trap in the sand washing and dewatering devices 10 is accumulated in closed containers. The mechanical cleaning unit 6 also includes tanks 5 of the average cost of wastewater by hours of the day. For the needs of averaging costs by the hours of the day, in the tanks 5 of the averagers, pumps 16 for supplying sewage through pressure pipelines 16 ^'were installed at the minimum inflow hours to the denitrifiers 11. Unit 6 is equipped with a forced ventilation system with air intake from outside the WWTP building. Since the mechanical wastewater treatment unit 6 is located indoors, the incoming air, having received unpleasant odors from wastewater, waste from it and sand pulp, is discharged to the blower inlet 7 for compression and supply through the pipelines 7 ^' to the denitrification aeration bubblers system 11, which in their tanks they have cassettes 13 with a fiber ruffled nozzle holding the biomass of organo-heterotrophic microorganisms, as well as free-floating activated sludge containing the same biocenosis in its community. Organoheterotrophs oxidize the organic matter of wastewater and foul-smelling impurities brought in with air, consuming air oxygen and nitrate oxygen coming from the return flow of activated sludge. The process of denitrification of nitrates is carried out because the content of oxygen dissolved in water in the denitrifiers 11 is maintained at a level of not more than 1 mg O ₂ / L by the dosed air supply for aeration through bubblers. The specific air consumption per 1 m ³ of denitrification volume reaches 2 m ³ / m ³ · h. When using up to 20% oxygen, i.e. about 50 g of O ₂ out of 1 m ^{3 of} air, up to 100 g of O ₂ / m ³ · h are introduced. The biomass of organoheterotrophs in 1 m ^{3 of the} volume of denitrifier 11 reaches 3 kg / m ³ for ash-free substance; therefore, the oxidative power of 1 m ^{3 of the} volume reaches 120 g O ₂ / m ³ · h. Consequently, the introduction of oxygen by air is less than the possibility of consumption, and oxygen nitrates is involved in the oxidation processes. The process of oxidation of organic substances by oxygen is accompanied by the formation of carbon dioxide and it is carried out with air from the denitrifiers 11 under the caps 14, with which the tanks of the denitrifiers are closed 11. From under the caps 14, the air exhausted in the denitrifiers 11 is taken in by blowers 15 and is pumped through pressure pipelines 15 ^' into the tank bubbler system nitrification 12. The specific demand for air at the nitrification stage does not exceed 1 m ^{3 of} air per 1 m ^{3 of the} volume of nitrification 12 per hour, but the volume of nitrification 12 is always twice as large is thinner than denitrifier 11; therefore, all air taken from under the hoods 14 of denitrifiers 11 is consumed in the bioreactors of nitrification 12 and ensures the introduction of the ammonia nitrogen necessary for oxidation into oxygen nitrates, although the oxygen content in 1 m ^{3 of} air has decreased from 20% by weight to 18%, and the carbon dioxide content in the air increased from 0.1% by weight in atmospheric air to 1% by weight in the air pumped by blowers 15. The increased amount of carbon dioxide in the air pumped into nitrification 12 has a beneficial effect on the growth of autoliths ofov-nitrifying and their rate of growth and life. At the same time, such a triple use of air inside the WWTP without going beyond it contributes to a reduction in the cost of rendering this type of WWTP waste neutralized and decontaminated. The air from the nitrification tanks 12 is discharged by fans 34 to the neutralization and disinfection unit 35, where it is first cleaned of dust and partially aerosols in the pre-filter 36, then it is processed in the gas-discharge cleaning unit 37 by the action of ozone obtained from an electric discharge, and then it is freed from the catalytic unit 38 excess ozone and residual amounts of harmful impurities and completely purified is discharged outside the WWTP building into the air basin.

The sludge mixture from nitrification 12 flows into the secondary thin-layer sedimentation tanks 17, where it is divided into two streams. A stream of clarified nitrified water and a stream of activated sludge of increased concentration. The stream of clarified water flows into the wastewater treatment unit 18, including a two-stage filter, filled in the first stage with cassettes 13 with a fiber ruffle nozzle, and in the second stage with granular anthracite. At the overflow from the first stage of the after-treatment unit 18 to the second stage, an aluminum or iron-containing reagent is introduced into the after-treatment water to bind the excess of waste water phosphates to insoluble substances, which are retained on the grains of anthracite and, during the regeneration of the after-treatment unit 18, are discharged with wash and regeneration waters into gravity sludge The stream of condensed activated sludge is also divided into two streams, one of which - return activated sludge is pumped by pumps 19 through pipelines 19 ^' to denitrifiers 11, and the second oh - excess activated sludge is pumped by the same pumps 19 through pipelines 20 into a gravity sludge compactor 22. A mixture of sediments condensed in a gravity sludge compactor 22 with a moisture content of 98% is sent by screw pumps 23 to a dewatering device 24, a sediment thickening and dewatering unit 21, to which it is dispensed from reagent farm 31 flocculant to increase the efficiency of sludge dewatering.

Nadilovaya water from the gravity sludge compactor 22 and the centrate from the dewatering device 24 through the pumping unit 25 is pumped into the wastewater stream in front of the denitrifier 11.

The wastewater treated in the aftertreatment unit 18 flows into the ultraviolet rays irradiation unit 32 for the treated wastewater and then is sent to the discharge pipelines 33 to the pumping station for technical water supply for use in the municipal utilities and industrial enterprises.

Sludge dehydrated in the device 24 is accumulated in the intermediate hopper 26 and then fed through the screw conveyor 27 to the paddle dryer 28 separately with the dehydrated waste 3 ^' and sand pulp 4 ^' . Sludge and waste water dried at a temperature of 240 ° C with a humidity of 25% are cooled in a special installation 29 to a temperature of 40 ° C and then sent to the packing and packaging unit 30, from where they are transported for storage or disposal outside the WWTP.

The first task - to achieve zero emission of wastes from WWTP into the environment around the WWTP was achieved by neutralizing and disinfecting the air and removing dried and decontaminated sediments from the WWTP premises in geometric packaging to disposal sites. Due to the triple reuse of the same volume of air, first for ventilation of the premises of the mechanical wastewater treatment unit, then for the denitrification process and, finally, for the nitrification process, the intake of external air for the needs of WWTP is reduced and, accordingly, the amount of neutralized air exhausted inside the WWTP is reduced. The use of closed nodes of treatment devices for mechanical and biological wastewater treatment inside WWTP certainly improves the working conditions of staff. The reduction in the land area for the treatment plant is due to the intensive management of the cleaning process and the compact placement of equipment inside the WWTP. According to the conclusion of the Sysin Institute in Moscow, the width of the strip of the sanitary protection zone around the WWTP with zero emission of waste into the environment allows it to be at the level of the width of transport highways surrounding the territory of WWTP.

This situation with the sanitary protection zone, as well as the architectural appearance (see Figure 2) for, for example, WWTP with a capacity of 50,000 m ³ / day allows you to allow WWTP to be built in the center of a residential development, thereby reducing the length of sewer networks, the number of pumping pumping stations and , creating the possibility of widespread use of purified water for the needs of technical water supply for enterprises, watering streets and green spaces (especially in the hot season), replacing the consumption of drinking water for the needs of water supply for technical toilets.

Claims (1)

A method of treating wastewater to produce purified water and neutralized waste, including filtering wastewater in grates, mechanical cleaning in sand traps, washing, pressing and drying waste from grates and sand traps, equalizing wastewater costs by the hours of the day using expense averaging tanks, biological treatment wastewater in step nitri-denitrification bioreactors with recirculation of activated sludge and biocenoses attached to a fiber brush nozzle; wastewater treatment in filtration plants solutions with a fibrous scrub nozzle, granular anthracite and dosing of reagents for binding phosphates to insoluble substances and retention of insoluble suspended solids, recovery of return and excess activated sludge in secondary thin-layer settlers, reactive treatment of activated sludge and dehydration together with sediment recovered from regeneration and washings tertiary treatment, disinfection of purified water by irradiation with ultraviolet rays, drying and decontamination of dehydrated sediments, characterized in that The ventilation air from the mechanical wastewater treatment plants is supplied by blowers to the stage of high-speed aerobic biological wastewater treatment by a community of organo-heterotrophs attached to a brush nozzle and consisting of free-floating activated sludge, the exhaust air released from the denitrification bioreactors by another group of blowers is pumped into the nitrification bioreactors, and allocated from the nitrification bioreactors, the exhaust air is passed through an electrocat system Before disinfection of neutralized air into the ambient air, dried at a temperature of 240 ° C to a humidity of 25% and disinfected and cooled to 40 ° C, waste from wastes and sewage sludge is packed and packaged in sealed block bags transported to places of storage or disposal.

Images