RU2572329C2 - Biological waste water treatment plant - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to apparatus for conducting mechanical, biological and physical-chemical purification of urban waste water and industrial waste water with similar composition and processing separated residues for preparation thereof for dehydration, decontamination and subsequent recycling, and can be used in treatment of domestic waste water via complete biological oxidation thereof, followed by post-treatment and decontamination of purified water according to current sanitary standards and rules and other regulations. The plant comprises a production building, process equipment placed inside the building, including a balancing tank-anaerobic reactor, a aeration tank-nitrifier provided with a floating charge for immobilising nitrifying biomass, a pneumatic aeration system and a settler-clarifier, a denitrifier, wherein the balancing tank-anaerobic reactor is provided with a heat exchanger for keeping temperature of the waste water not lower than 22°C; the denitrifier is provided with a mixer for keeping the sludge mixture in a suspended state, and the aeration tank-nitrifier is separated from the denitrifier by a half-submerged partition wall for enabling circulation of the sludge mixture; wherein the plant is provided with a coagulant feeding and preparation unit, a post-treatment biofilter, at the bottom of which there are disc aerators; sorption gravity filters which are arranged to be washed by the purified water; an ultraviolet disinfection apparatus; an apparatus for feeding biogenic elements for ensuring stable purification; air blowers for providing the waste water treatment process with air; an air lift for pumping decontaminated residue into a filter sack for dehydration.

EFFECT: creating a block modular biological waste water treatment station, which provides waste water treatment quality with acceptable costs to a level which allows discharge thereof into fishing reservoirs.

5 cl, 3 dwg

Description

The invention relates to a device for conducting processes of mechanical, biological and physico-chemical treatment of urban and similar industrial wastewater composition and processing of precipitates to prepare them for dehydration, disinfection and subsequent disposal, and can be used in the treatment of household wastewater waters by their complete biological oxidation with subsequent purification and disinfection of purified water in accordance with applicable sanitary and epidemiological norms and rules E and other regulatory documents.

Known wastewater treatment plant for biological treatment of domestic wastewater (RF patent No. 2404141, class C02F 9/14, 3/00, 2010), containing a technological building with pumps, pipelines for supplying the source and discharge of treated effluents with shut-off and control valves, block biological treatment in the form of a biological treatment plant with aeration tank, primary and secondary sedimentation tanks. The biological treatment unit consists of several groups of the same biological treatment plants, made with the possibility of deepening them and equipped with technological and inspection necks for communication with the day surface, with each group of the said plants installed on its foundation plate, and all the base plates of the said groups of plants are made recessed and are located at the same level not lower than the location of the buried part of the technological building, and each group of installations is equipped with on its distribution tank, aeration system and collector pipe for respectively supplying effluents, their aeration and drainage of purified water, while the distribution tanks and aeration systems of each group of plants are connected to the respective feed pumps and compressors, while the collector pipelines of each group of plants are connected through a tank for collecting biologically purified water, common to all groups of plants, to the purified water discharge line.

This station allows for the efficient treatment of domestic wastewater.

However, it still does not cleanly remove suspended solids, BODfull, nitrogen and phosphorus compounds.

Known biological wastewater treatment plant (RF patent No. 2466104, class C02F 9/14, 3/30, 2012), adopted by the applicant for the prototype. It contains an anaerobic-anoxide reactor, the volume of which is connected via a hole partition to the aeration volume of a high-load aerotank mixer. The station is made in the form of a single cylindrical production building and contains the production building itself and the block of technological tanks, consisting of four technological segments with the possibility of independent parallel operation of their technological lines, made in the form of radial channels, each of the segments contains an anaerobic-anoxide reactor, divided into the anaerobic part, the pre-oxide part and the anoxide part, in which the mechanical stirrers are placed, a heterotrophic step comprising high loaded aeration tank mixer, equipped with a pneumatic aeration system and a two-stage thin-layer sludge separator, in the central part of which there is a two-section sludge chamber with low-pressure pump units, each section of the sludge chamber is connected by a perforated pipe located in the lower zone of the thin-layer modules in each stage of the two-stage and low-level thin section its zone is a sludge distribution system with the ability to ensure consistent operation with tupeni in countercurrent mode, each of its stages is equipped with a system for regenerating the inter-shelf space of thin-layer modules in each stage, each section of the sludge chamber corresponding to its own stage of a two-stage thin-layer sludge separator with the possibility of achieving hydraulic independence when regulating the selection of the sludge mixture from each of its stages, the heterotrophic stage is connected to autotrophic step system of prefabricated trays of a two-stage thin-layer sludge separator, autotrophic step contains a a knot of a nitrifying propellant equipped with a floating charge for immobilizing the nitrifying biomass, a pneumatic aeration system and a clarifier clarifier, in which two zones are made in height, successively located from bottom to top along the course of the clarified suspension, the lower zone is made in the form of a thin-layer settler, and the upper zone above it in the form of a bioreactor with loading to immobilize the attached microflora carried out from the aeration tank of the nitrification propellant-propellant, each zone of the clarifier-clarifier is equipped with on a regeneration system, a system for collecting and discharging clarified wastewater, a drainage system is connected to the distribution system of the built-in contact chamber for flocculation of the prefilter with a load, the prefilter is equipped with a system for loading regeneration and a system for collecting and discharging purified water, which is connected via pipelines to the quick filter unit with alternating direction filtration in the moving layer of granular loading, the block of technological tanks is equipped with a vertical flow-type desilator with built-in second flocculation chamber type eddy sealingly excess active biomass.

At this biological wastewater treatment plant, the processes of oxidation of carbon-containing organic substances and nitrogen of ammonium salts are separated, which proceed sequentially in separate technological volumes.

It differs from the known solutions by the presence in each stage of cleaning of its own separation zones, differing in functional purpose, for example, in the heterotrophic stage, the functional purpose of the separation zone is the concentration of biomass in the heterotrophic system, and in the autotrophic stage it is the separation (clarification) of the suspension into purified water and a removable attached biofilm from an autotrophic step, followed by filtration of clarified water through the charge.

In addition, it differs from the known solutions by the presence of a preanoxide stage in the anaerobic-anoxide zone.

However, this station is not effective enough in purification of suspended solids and compounds of nitrogen and phosphorus.

An object of the invention is the creation of a modular block station for biological wastewater treatment, which ensures the quality of wastewater treatment with accepted costs to a level that allows their discharge into fisheries.

The problem is solved in that in the proposed solution, the averager-anaerobic reactor is equipped with a heat exchanger to maintain the temperature of the wastewater at least 22 ° C, and it is also configured to partially dephosphate; the denitrifier is equipped with a mixer to maintain the sludge mixture in suspension, and the aeration tank-nitrifier is divided with the denitrifier by a semi-submerged partition to circulate the sludge mixture; moreover, the biological treatment station is equipped with a coagulant preparation and dosing unit, a post-treatment biofilter, at the bottom of which disk aerators are laid; pressure sorption filters that are installed with the possibility of washing with purified water; installation of ultraviolet disinfection; installation of dosing of nutrients to ensure stable cleaning; blowers to provide air for the wastewater treatment process; airlift for pumping disinfected sludge into a filter bag for dehydration.

In addition, disk aerators are installed at the bottom of the nitrotifier aeration tank to saturate the silt mixture with oxygen.

In addition, a polymer charge is installed in the aeration tank-nitrifier and averager-anaerobic reactor to increase the concentration of sludge in the reactor, as well as to increase the age of the sludge.

In addition, a bubbler is installed in the biofilter for post-treatment to shake the polymer charge.

In addition, for wastewater disinfection, the station contains a unit for the preparation and dosing of sodium hypochlorite.

The technical result from the use of the present invention is that the station successfully removes suspended solids, BODfull, nutrients: nitrogen and phosphorus compounds; destroys bacterial pollution, reduces BOD completely.

In this case, the organic substances of the effluents undergo biosorption and biochemical oxidation under the influence of the biocenosis of bacteria, which form activated sludge. Bacteria of activated sludge are able to form colonies (flocks), which are easily separated from purified water during sedimentation.

In FIG. 1 shows a flow chart of a biological wastewater treatment plant;

in FIG. 2 shows a plan for the placement of technological equipment at a biological wastewater treatment plant;

in FIG. Figure 3 shows the block-modular design of the station building without placing technological equipment.

The biological wastewater treatment plant is intended for wastewater treatment, supplied to it from sanitary appliances of domestic premises, administrative and industrial buildings, wastewater from canteens, etc. etc.

The production building of the station is made in a complete block design, inside which the necessary technological and engineering equipment is located, which ensures the operation of the station, including in automatic mode, as well as the power supply, heating and ventilation systems that each block module is supplied with, of which the production station building. The indicated systems are made in accordance with applicable norms and rules.

The technological equipment used in the work of the station ensures the quality of wastewater treatment to a level that allows their discharge into reservoirs of fishery destination and the corresponding MPC of these reservoirs.

The domestic wastewater treatment process includes the following stages: mechanical treatment, biological treatment, wastewater treatment, wastewater disinfection and sludge treatment.

The stage of mechanical treatment of domestic wastewater is carried out by means of a sewage pumping station 1 (SPS), in which a trellis basket 2 and pumps 3 with a cutting mechanism are installed, intended for grinding large waste and collecting it.

At the stage of biological treatment itself, an averager-anaerobic reactor 4 is used to equalize the station productivity and the concentration of the substances to be purified, aeration tank-nitrification 5 and denitrification 6 to increase the concentration of sludge in the averager-anaerobic reactor 4, as well as to increase the age of the sludge due to the polymer load used. In addition, for sedimentation and clarification of the treated wastewater, a clarifier-clarifier, made as a secondary clarifier 7, is used, and dephosphotization chambers 8 and 9 are used to remove phosphates and phosphorus-containing substances.

Polymer loading, or, as it is correctly called, a biological loading unit (BBZ) is a three-dimensional mesh structure consisting of polymer pipes with a diameter of 65 mm, placed parallel to each other and welded at the ends between each other in places of contact.

The mesh elements function as the habitat of immobilized microorganisms in the biological treatment systems of industrial, domestic, wastewater, biofilters and cleaning systems for fish farms.

The mesh elements of a cylindrical-shaped block are formed by the intersection of polymer fibers with a thickness of 3 mm, with the formation of cells in the form of a rhombus, with diagonals not exceeding 25 and 55 mm, the number of threads in one element is 16 pcs. BBZ-2.6 blocks are made of low pressure polyethylene PND 273-83 GOST 16338-85, stabilized by carbon against ultraviolet aging.

The biological loading unit (BBZ) is used as a biomass carrier to intensify the flow of biological processes in biological treatment systems for domestic and industrial wastewater.

The method and area of installation, as well as the number and modification of the blocks is determined individually for each structure.

The cleaning efficiency can be increased up to 4 times, which, in turn, significantly reduces operating costs.

The design geometry of the BBZ block allows for a uniform distribution of air flow during forced aeration, the weld seam of the stiffness membrane provides reliable fastening of the mesh shells that make up the block.

Advantages of biological loading units (BBZ):

- resistance to deformation (the possibility of free movement of the block during installation);

- production of 100% environmentally friendly raw materials, the porosity of the block provides good aeration and oxygen access to the biofilm;

- resistance to UV radiation;

- self-regulation of the thickness and composition of the film;

- it does not become clogged, self-cleaning (upon reaching a certain thickness of the biofilm, mineralized microorganisms remove themselves from the load and fall into the secondary sedimentation tank, precipitate in it);

- fit into any size of containers, biofilters, reactors;

- when toxins enter the system and the destruction of microorganisms, a quick recovery of the activity of activated sludge occurs;

- resistance to biologically and chemically active substances.

The stage of post-treatment of wastewater is carried out on biofilters 10 of post-treatment with flooded loading from prismatic material and pressure sorption filters 11 and 12 with loading from activated carbon, which are installed with the possibility of washing with purified water. One of the sorption filters is a working one, and the other is a reserve one. The content of suspended solids in the treated wastewater after biofilter 10 entering the sorption filters 11 and 12 should not exceed 5 mg / l.

The wastewater disinfection stage is performed using a highly efficient ultraviolet (UV) disinfection unit 13, in which ultraviolet lamps are installed.

At the stage of processing the sludge, namely, excess sludge, sludge is stabilized with air oxygen from the air blowers 14, and sludge is dehydrated and decontaminated in the sludge dewatering unit 15 and in the decontamination and deworming chamber 16.

The dehydration unit 15 has a filter bag. Also, her work provides for the addition of chamber 16 to the pit 2 hours before the start of dehydration of sodium hypochlorite for disinfection and deworming in an amount of 4 g / m ^{3 of a} water-sludge mixture. The moisture content of the sludge at the outlet of the dehydration unit 15 should be no more than 80%. Filled filter bags with stabilized, dehydrated and decontaminated sludge are accumulated at the temporary storage site for waste, followed by their removal to the solid waste landfill.

To ensure clear and uninterrupted operation of the wastewater treatment plants of the station in a given technological mode, a unit for the preparation and dosing of sodium hypochlorite 18, which is used to disinfect wastewater as a chloride compound, but the least harmful, is provided; coagulant preparation and dosing unit 17, blower 14 (operating and standby), washing water tank 19 for filter washing and washing pump 20.

The blocks for the preparation and dosing of coagulant 17 and sodium hypochlorite 18 are equipped with a water supply from the water supply network 21 according to a constant scheme (with a jet break) and nozzles with valves for draining the liquid into the gangway using a portable hose. As a coagulant or reagent, aluminum polyoxychloride is selected.

In addition, the biological wastewater treatment plant includes a plant 22 for feeding biogenic elements, which is designed to remove suspended solids, BODfull, as well as biogenic elements (nitrogen and phosphorus compounds). In it, the organic substances of the effluents are subjected to biosorption and biochemical oxidation under the action of the biocinosis of bacteria, which form activated sludge. Bacteria of activated sludge are able to form colonies (flocks), which are easily separated from purified water during sedimentation.

The removal of nutrients is based on the ability of microorganisms to use them in the process of their life when creating optimal conditions for this. Nitrifying bacteria contained in activated sludge are able to oxidize ammonium nitrogen to nitrates in the presence of dissolved oxygen. The nitrification process (ammonium nitrogen oxidation) occurs under the aerobic conditions of the aerobic stabilizer 23 (in the presence of oxygen) and begins after the completion of the stage of oxidation of organic substances. Therefore, this process is designed for extended aeration. To saturate the sludge mixture with oxygen, fine-bubble aeration is used. One of the main conditions for successful nitrification is the high age of the sludge, which is achieved by equipping the aeration tank-nitrifier 5 with polymer loading. Polymer loading is overgrown with immobilized microflora, which prevents the removal of sludge from the system. Denitrification (reduction of nitrates to nitrogen gas) in denitrifier 6 occurs under anoxic conditions (oxygen is present only in bound form). The sludge mixture circulates between the anoxide and aerobic zones.

In biocinosis of activated sludge, phospho-accumulating organisms are present. A distinctive feature of these microorganisms is their ability to consume large amounts of phosphate under aerobic conditions, which they use as an energy reserve, allowing them to decompose the substrate under anaerobic conditions.

Thus, sludge, circulating in the system, passes through three zones - aerobic, anoxic and anaerobic, in which nitrification, denitrification and dephosphation occur, respectively.

Residual contaminants are removed on sorption filters, before which a post-treatment on a flooded biofilter is arranged.

With a deficiency of macronutrients (nitrogen or phosphorus), the source water is fed with the missing elements.

Station biological wastewater treatment is as follows.

Wastewater flows into the sewage treatment plant 1 of domestic wastewater (HBSV), equipped with submersible pumps 3 with a cutting mechanism and trash-holding grate baskets 2.

From SPS 1 HBSV, pumps 3 supply wastewater to the anaerobic homogenizing reactor 4, in which the wastewater is averaged qualitatively, and in order to prevent the suspension of suspended solids, it is provided for bubbling by means of a bubbler 24. To maintain the temperature of the treated wastewater not lower than 22 ° С, the averager the anaerobic reactor 4 is equipped with a heat exchanger 25. The averager-anaerobic reactor 4 also acts as an anaerobic reactor for partial dephosphation, where the sludge mixture from the denitrifier 6 is fed through the recycle pump 26. the overflow pipe flows into the denitrifier 6. Together with them, circulating activated sludge from the secondary settling tank 7 is supplied to the denitrifier 6. To keep the sludge mixture in suspension, an agitator 27 is installed in the denitrifier 6. The aeration tank 5 is separated from the denitrifier 6 by a semi-submerged partition 28, thanks to which is the circulation of the silt mixture between the aerobic and anoxic zones. To saturate the sludge mixture with oxygen, disk aerators 29 are installed at the bottom of the nitrotifier 5 aeration tank, which have a high efficiency of dissolving oxygen in water. A polymer charge is installed in the aeration tank-nitrifier 5 and the averager-anaerobic reactor 4, which serves to increase the concentration of sludge in the averager-anaerobic reactor 4, as well as to increase the age of the sludge, which are necessary conditions for successful nitrification.

From the aeration tank-nitrifier 5, the sludge mixture enters the secondary sump 7. In the secondary sump 7, the sludge mixture is separated into sludge and purified water. The sludge settled in the secondary sump 7 is pumped to the denitrifier 6 by a pump 30. The water thus clarified enters the dephosphotization chamber 9. 5% aluminum sulphate is used for chemical precipitation of phosphorus. For the preparation and dosing of the coagulant, a reagent farm is provided, made in the form of a block for the preparation and dosing of the coagulant 17.

After the reagent treatment, water is supplied through the dispenser to the flooded post-treatment biofilter 10. Disk aerators 29 are also placed at the bottom of the biofilter 10. A bubbler is provided for shaking the polymer charge 24. After the biofilter 10, wastewater with a suspended matter concentration of not more than 5 mg / l is collected in the intermediate containers 31, from where, by submersible pumps 32, they are directed to pressure-absorbing sorption filters 11 and 12. The remaining contaminants are removed on the sorbent, and deep removal of organic substances occurs. Washing of the sorption filters 11 and 12 is carried out with purified water. The purified water is accumulated in the washing water tank 19. The capacity of the tank is calculated for two washes. It is also envisaged to fill the tank 19 with water from the water supply network 21. A flush pump 20 is installed in the tank 19. Dirty water from the flush and the first filtrate is discharged through gravity drainage system to the sewage pumping station 1 HBSV. Ultraviolet lamps are used to disinfect treated effluents. Disinfected and purified water through a pressure pipe enters the SPS 33 of treated wastewater (WWS) and then pumps to discharge.

The precipitate formed during the cleaning process is represented by excess sludge, biofilm and precipitated as a result of reagent treatment with aluminum phosphate. Sludge is collected in the conical part of the secondary sump 7, biofilter 10 of the aftertreatment and dephosphorization chamber 8, respectively, and gravity is sent to the aerobic stabilizer of the sludge 23. The stabilized sludge through the baffle 34 enters the disinfection and de-dehumidification chamber 16. Sodium hypochlorite is used as the disinfecting reagent, which is supplied by the pump -doser in the amount of 4 g / m ³ water-sludge mixture. The disinfected sludge with airlift 35 is pumped into the filter bag for dehydration. The resulting filtrate is discharged to gravity drainage system 1 at HBSV through a gravity drainage system. The moisture content of the sludge at the outlet of the dehydrator is not more than 80%.

To ensure the stability of the cleaning process, an installation 22 for feeding it with biogenic elements is provided. If nitrogen or phosphorus is deficient in wastewater, an appropriate reagent is added to the aeration tank-nitrification 5.

Technological needs are supplied by blowers 14.

Using the proposed technical solution, it was possible to create a complete biological wastewater treatment plant that ensures the quality of wastewater treatment, corresponding to the maximum permissible concentration of pollutants in fishery ponds, namely, it successfully removes suspended solids, BOD full, nutrients: nitrogen and phosphorus compounds; destroys bacterial pollution.

Claims (5)

1. Biological wastewater treatment plant, comprising a production building, technological equipment located inside the building, including averaging anaerobic reactor, aeration tank-nitrifier equipped with a floating charge for immobilization of nitrifying biomass, a pneumatic aeration system and clarifier clarifier, denitrification, characterized in that that the averager-anaerobic reactor is equipped with a heat exchanger to maintain the temperature of the wastewater at least 22 ° C; the denitrifier is equipped with a mixer to maintain the sludge mixture in suspension, and the aeration tank-nitrifier is divided with the denitrifier by a semi-submerged partition to circulate the sludge mixture; moreover, the station is equipped with a coagulant preparation and dosing unit, a post-treatment biofilter, at the bottom of which disk aerators are laid; pressure sorption filters that are installed with the possibility of washing with purified water; installation of ultraviolet disinfection; installation of dosing of nutrients to ensure stable cleaning; blowers to provide air for the wastewater treatment process; airlift for pumping disinfected sludge into a filter bag for dehydration. 2. The station according to claim 1, characterized in that disk aerators are installed at the bottom of the nitrotifier-aeration tank to saturate the silt mixture with oxygen. 3. The station according to claim 1, characterized in that a polymer charge is installed in the aeration tank-nitrifier and averager-anaerobic reactor to increase the concentration of sludge in the reactor, as well as to increase the age of the sludge. 4. The station according to claim 1, characterized in that a bubbler is installed in the biofilter for post-treatment to shake the polymer load. 5. The station according to claim 1, characterized in that for the disinfection of wastewater the station contains a unit for the preparation and dosing of sodium hypochlorite.

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