CN116693110A - A treatment system and process for realizing urban sewage reuse - Google Patents

Abstract

This application discloses a treatment system and process for realizing the reuse of urban sewage. The treatment system includes a coarse grid, a fine grid, a grit chamber, a biochemical unit, a secondary sedimentation tank, an air flotation device, a filter cloth filter, etc. Pool, contact disinfection pool and deployment pool; coarse screen and fine screen can remove suspended solids, floating solids, etc. in turn; grit chamber can remove larger organic particles in sewage; microorganisms in biochemical unit can reduce sewage COD, Nitrogen and phosphorus, etc.; the secondary sedimentation tank can realize the separation of mud and water; the air flotation device can remove fine stickies; the filter cloth filter can remove suspended solids; the contact disinfection tank can kill pathogenic microorganisms, and the treated reclaimed water flows to the deployment pool. Finally, it will be reused in the light pollution wastewater treatment system of the park. Therefore, the treatment system and process provided by this application can carry out full-process treatment of urban sewage, realize the resource utilization of urban reclaimed water, further dilute industrial wastewater to a certain extent, and reduce the difficulty of industrial wastewater treatment.

Description

A treatment system and process for realizing urban sewage reuse

technical field

The application relates to the technical field of urban sewage treatment, in particular to a treatment system and process for realizing the reuse of urban sewage.

Background technique

With the development of industrialization, environmental problems have become increasingly prominent. The deterioration of urban water environment will undoubtedly aggravate the shortage of water resources. In order to achieve sustainable development, urban sewage treatment is urgent.

Urban sewage includes domestic sewage and rainwater. Domestic sewage is mainly wastewater discharged from residents' daily life, such as residences, schools, hospitals, shops and public places. Pollutants in domestic sewage are mainly organic matter (such as protein, carbohydrates, fats, etc.) , urea and ammonia nitrogen, etc.) and a large number of pathogenic microorganisms (such as parasite eggs and intestinal infectious viruses, etc.), the organic matter in domestic sewage is unstable, easy to rot and produce stench, and bacteria and pathogens use organic matter in domestic sewage Mass reproduction for nutrition can lead to the spread of infectious diseases.

The current urban sewage treatment methods include AB method, SBR method, A ² /O method and so on. In the AB method, the aeration tank is divided into two levels of oxygen supply according to high and low loads. A level has a high load, aeration time is short, and a large amount of sludge is generated; B level has a low load and a longer sludge age; A level and B level There is an intermediate sedimentation tank between them. Although the AB method has the advantage of saving energy, it is not suitable for low-concentration water quality. The SBR method integrates water inflow, aeration, sedimentation, and water outflow in one pool. It usually consists of three or four pools, which operate in turn and run intermittently one by one, so it is called sequence batch activated sludge method. , but this method is not suitable for large-scale urban sewage treatment. The A ² /O method is a process composed of anaerobic-anoxic-aerobic. It uses biological treatment to remove nitrogen and phosphorus to obtain high-quality effluent. It is a deep secondary treatment process. It can be seen that the existing urban sewage treatment methods have requirements for water quality and quantity treatment, the treatment range is limited, and the adaptability is not strong.

In order to solve the above problems, Chinese patent document CN200810118942.4 discloses an urban sewage treatment system and method, which adopts the treatment process of anaerobic pond + oxidation ditch. After the sewage passes through the medium grid and the fine grid, the large and small suspended solids are basically removed, and then enters the aeration grit chamber to settle the inorganic particles such as large particles of sand, stones, cinders, etc. Oxygen tank and oxidation ditch, in the oxidation ditch, the mixed solution of sewage and activated sludge is continuously circulated under the action of external power, organic matter is degraded under the action of microorganisms, and nitrogen and phosphorus are also well removed , the effluent enters the secondary settling tank, the effluent after mud-water separation is sterilized and can reach the standard discharge, and the remaining sludge is transported away after concentration and dehydration.

Although the solution provided by this patent document has strong adaptability to water quality and quantity, the treated effluent is finally discharged after being sterilized to meet the standard, which only realizes the environmentally friendly discharge of sewage and is not further utilized. Therefore, it is invested in sewage treatment. Material and financial resources are only for environmental protection, and no further value utilization has been realized, and there is a problem of waste of resources. Therefore, it is urgent to propose a new technical solution to solve the problems in the prior art.

Contents of the invention

This application provides a treatment system and process for realizing the reuse of urban sewage, which is used to solve the problem of waste of resources existing in the disinfection discharge of existing urban sewage after treatment.

In order to achieve the above object, the application provides the following technical solutions:

On the one hand, the present application provides a treatment system for realizing the reuse of urban sewage, including a coarse grid, a fine grid, a grit chamber, a biochemical unit, a secondary sedimentation tank, an air flotation device, a cloth filter tank, a contact disinfection tank and Deployment pool; wherein, the coarse grid is set in the irrigation canal used to transport urban sewage; the sewage filtered through the coarse grid flows through the fine grid for secondary filtration; filtered through the fine grid The final sewage flows into the grit chamber, the grit chamber is provided with a stirring impeller, and the bottom of the grit chamber is provided with a sand bucket; , RPIR tank and secondary settling tank, select anaerobic tank and secondary settling tank to be connected with the inlet of the return sludge pump; anaerobic tank and RPIR tank are connected by pipelines to form mud-water mixture backflow; the outlet of the grit chamber is connected to the The water inlet of the selective anaerobic tank is connected; the water outlet of the secondary sedimentation tank is connected with the water inlet of the air flotation device; the water outlet of the air flotation device is connected with the filter cloth filter, and the filter cloth filter, contact The disinfection pool and the deployment pool are connected in sequence; the deployment pool is provided with a water outlet port adapted to the reuse water pipe of the park.

In the above technical solution, the coarse grid includes a frame and one or more groups of parallel metal grid bars installed on the frame, and several grids are formed on the metal grid bars; the coarse grid is arranged obliquely on the It is used in irrigation canals for transporting urban sewage.

Further, the fine grid includes a frame and one or more groups of parallel metal grid bars installed on the frame, and several grids are formed on the metal grid bars.

Further, the sewage filtered by the coarse grid is lifted to the water inlet side of the fine grid by a lift pump.

Further, the grit chamber is a swirl grit chamber, the bottom of the swirl grit chamber forms a sand collection bucket, and a stirring impeller is arranged in the pond. When the impeller rotates, the sand particles in the water will The slope is collected in the sand collection hopper, and the organic matters adhered to the sand particles are separated; the cyclone grit chamber is also provided with an air lift pump or a self-priming sand pump for discharging the sand particles in the sand collection hopper.

Further, the water inlet of the selective anaerobic tank is connected to the water outlet of the cyclone grit chamber, the water outlet of the selective anaerobic tank is connected to the water inlet of the anaerobic tank, and anaerobic Bacteria; the RPIR pool is provided with a water inlet port and a water outlet port, the water inlet port is connected to the water outlet of the anaerobic tank, the water outlet port is connected to the secondary sedimentation tank, and the RPIR pool is connected to the anaerobic tank through the mud-water mixture return communication pipeline .

Further, the RPIR tank includes a tank body, multiple aeration devices and multiple circulation clarifiers; the tank body is provided with an aerobic unit in the vertical space, and a mud-water separation zone is provided inside the circulation clarifier.

Further, the secondary settling tank includes a tank body, in which a water inlet area, a sedimentation area, a buffer zone, a sludge area and a water outlet area are sequentially formed.

Further, the air flotation device includes a pool body, which sequentially forms an aeration area, an air flotation area, a slag discharge area and a drainage area; a water inlet is provided on the side wall of the aeration area, and an aerator is installed in the aeration area , There is a slag scraper on the top of the pool body, a slag discharge port is set on the side wall of the pool body, and a drain port is set on the side wall of the drainage area.

Further, the filter cloth filter is provided with a hollow rotating shaft, and a filter cloth and a filter disc are arranged on the hollow rotating shaft, and the water entering the filter cloth filter enters through the small holes on the filter cloth under the action of gravity pressure difference. When reaching the filter disc, the solid suspended solids are trapped outside the filter cloth, and the filtrate converges into the hollow shaft through the filter disc and flows into the outlet tank, and is discharged from the filter cloth filter through the outlet weir plate.

Further, a disinfectant is added to the sewage in the contact disinfection tank, and the disinfectant contains hypochlorite.

Further, the reuse water pipe of the park is connected with the light pollution wastewater treatment system of the park.

On the other hand, based on the above-mentioned treatment system for realizing the reuse of urban sewage, the present application also provides a treatment process for realizing the reuse of urban sewage, which includes the following steps:

S1: Set up coarse screens in the irrigation canals that transport urban sewage, and use the coarse screens to remove coarse suspended matter, floating matter, fibrous matter and solid particulate matter;

S2: The water filtered by the coarse screen is lifted to the fine screen, and the fine screen is used to remove the small floating and suspended matter in the sewage;

S3: The water filtered by the fine grid is transported to the grit chamber to remove larger organic particles in the sewage;

S4: The water treated by the grit chamber is sent to the biochemical unit to reduce the chemical oxygen demand and nitrogen and phosphorus under the action of microorganisms;

S5: The sewage treated by the biochemical unit is sent to the secondary settling tank to realize the separation of mud and water;

S6: The supernatant of the secondary sedimentation tank enters the air flotation device to remove fine stickies;

S7: The effluent from the air flotation device enters the filter cloth filter to remove suspended matter;

S8: The effluent from the filter cloth filter enters the contact disinfection tank, the effluent from the contact disinfection tank enters the deployment pool, and the water in the allocation pool is reused for the light pollution wastewater treatment system in the park.

Compared with the prior art, the present application has the following beneficial effects:

This application provides a treatment system for realizing the reuse of urban sewage, which can treat the urban sewage and reuse it in the light pollution wastewater treatment system of the industrial park; the treatment system for realizing the reuse of urban sewage provided by the application passes through the coarse grid Remove coarser suspended matter, floating matter, fibrous matter and solid particulate matter; remove smaller floating matter and suspended matter through a fine screen; remove larger organic particles in sewage through a grit chamber; remove microorganisms in a biochemical unit Reduce COD, nitrogen and phosphorus under the action; realize the separation of mud and water through the secondary sedimentation tank; remove fine sticky matter through the air flotation device; remove suspended matter through the filter cloth filter; finally enter the contact disinfection tank to kill bacteria, viruses and pathogenicity The microorganisms then flow to the deployment pool, and are finally reused in the light pollution wastewater treatment system of the park. Therefore, the treatment system and process for realizing the reuse of urban sewage provided by this application can carry out the whole-process treatment of urban sewage, realize the resource utilization of urban reclaimed water, and dilute industrial wastewater to a certain extent, reducing industrial pollution. Difficulty in wastewater treatment.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the accompanying drawings that need to be used in the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present application. For Those skilled in the art can also obtain other drawings based on these drawings without any creative work. It should be understood that the specific shapes and structures shown in the accompanying drawings should generally not be regarded as limiting conditions for the implementation of the present application; for example, those skilled in the art are able to The increase/decrease/attribution division, specific shape, positional relationship, connection mode, size ratio relationship, etc. of some units (parts) are easy to make conventional adjustments or further optimization.

Fig. 1 is the flow chart of a kind of treatment system that realizes urban sewage reuse provided by the application;

FIG. 2 is a schematic diagram of the structure and principle of the RPIR pool used in the processing system provided in the present application in an embodiment.

Explanation of reference signs:

1. Coarse grid; 2. Lifting pump; 3. Fine grid; 4. Cyclone grit chamber; 5. Select anaerobic tank; 6. Anaerobic tank; 7. RPIR tank; 71. Tank body; 72. Outlet weir; 73. Aeration device; 74. Circulation clarifier; 75. Mud-water separation area; 8. Secondary settling tank; 9. Air flotation device; 10. Filter cloth filter tank; 11. Contact disinfection tank; ; 13. Return sludge pump; 14. Sludge storage tank; 15. Mud-water mixture return flow communication pipe;

A. The aeration direction of the aeration device; B. The direction of the activated sludge return flow.

Detailed ways

The present application will be further described in detail through specific embodiments below in conjunction with the accompanying drawings.

In the description of this application: unless otherwise specified, "plurality" means two or more. The terms "first", "second", and "third" in this application are intended to distinguish the referred objects, and have no special meaning in terms of technical connotation (for example, it should not be understood as a reference to the degree of importance or order, etc. emphasis). Expressions such as "comprising", "including", and "having" also mean "not limited to" (certain elements, components, materials, steps, etc.).

Terms such as "upper", "lower", "left", "right", "middle", etc. quoted in this application are usually for the convenience of intuitive understanding with reference to the drawings, rather than absolute terms for the positional relationship in the actual product limited. Without departing from the technical concept disclosed in this application, changes in these relative positional relationships should also be regarded as the scope of this application.

Embodiment one

In order to solve the problems existing in the prior art, this application provides a treatment system and process for realizing the reuse of urban sewage. After being treated by the treatment system, the urban sewage can be reused in the light pollution wastewater treatment system of the industrial park to realize the reuse of water resources. use.

This application builds a new system for urban sewage treatment. Compared with the traditional treatment system for disinfection and discharge of urban sewage after treatment, the treatment system for realizing the reuse of urban sewage provided by this application can realize the reuse of reclaimed water after treatment. Applying the treatment system provided in this application to an urban sewage treatment plant can realize the reuse of reclaimed water after urban sewage treatment to the light-polluted wastewater treatment system in industrial parks, and realize resource recycling.

The process route of a treatment system for realizing the reuse of urban sewage provided by this application can be briefly summarized as follows: the urban sewage is transported to the coarse grid 1 of the urban sewage treatment plant through irrigation canals, and the coarser grids 1 that may block the water pump unit and pipeline valves are removed. Suspended matter, floating matter, fibrous matter and solid particulate matter, etc.; then pumped to the fine grid 3 to remove smaller floating matter and suspended matter; then enter the grit chamber, mainly to remove larger organic particles in the sewage Then enter the biochemical unit (select anaerobic tank 5+anaerobic tank 6+RPIR pool 7+secondary sedimentation tank 8), reduce COD, nitrogen and phosphorus, etc. under the action of microorganisms in the biochemical unit, and the second sedimentation tank 8 realizes mud-water separation, The supernatant of the secondary settling tank 8 enters the air flotation device 9 to remove fine stickies. The effluent from the air flotation device 9 enters the filter cloth filter 10 to remove suspended solids and further improve the quality of the effluent. Finally, the waste water enters the contact disinfection tank 11 to kill Dead bacteria, viruses and pathogenic microorganisms, etc., flow to the allocation pool 12, and finally reused in the light pollution wastewater treatment system of the park.

The system architecture and working principle of a treatment system for realizing urban sewage reuse provided by the present application will be described in detail below.

A treatment system for realizing urban sewage reuse provided by this application includes a coarse grid 1, a lift pump 2, a fine grid 3, a grit chamber, a biochemical unit, an air flotation device 9, a filter cloth filter 10, Contact disinfection pool 11 and deployment pool 12. The above-mentioned biochemical unit includes sequentially connected selective anaerobic tank 5, anaerobic tank 6, RPIR tank 7 and secondary sedimentation tank 8; wherein, selective anaerobic tank 5 and secondary sedimentation tank 8 are connected to the inlet of return sludge pump 13 respectively , the outlet of the return sludge pump 13 is connected to the sludge storage tank 14, and the sludge storage tank 14 is connected to the sewage plant in the park; the anaerobic tank 6 and the RPIR tank 7 form a mud-water mixture backflow.

The coarse grid 1 used in the treatment system provided by this application is composed of a frame and one or more sets of parallel metal grid bars installed on the frame. When in use, install it obliquely in the water inlet channel to intercept coarse suspended solids and impurities in the sewage. The above-mentioned channel is the inflow irrigation canal for transporting urban sewage. Installing the coarse grille 1 in the inflow irrigation canal can remove coarse suspended matter that may block the back pump unit and pipeline valves, and ensure the normal operation of the follow-up treatment facilities.

The urban sewage in the inlet irrigation canal is filtered by the coarse grid 1, and then pumped by the lift pump 2 to the fine grid 3 for secondary filtration.

The structure of the fine grid 3 used in the processing system provided by the present application is basically the same as that of the coarse grid 1, both of which are composed of a frame and one or more groups of parallel metal grid bars installed on the frame. The difference between the two is only the aperture size of the grid on the grid bar. Compared with the grid aperture of the coarse grid 1, the grid aperture of the fine grid 3 is smaller, and can filter suspended matter with small particle size.

The urban sewage filtered through the fine grid 3 for the second time has removed suspended matter, floating matter, fibrous matter and solid particle matter with smaller particle sizes, and then enters the grit chamber to remove larger organic particles in the sewage.

The grit chamber used in the treatment system provided by this application is a grit chamber that uses the mechanical force formed by the agitator to control the flow state and velocity of the water flow, and uses the centrifugal force formed by the agitation to accelerate the sedimentation of sand particles and allow the organic matter to be taken away with the water flow.

The cyclone grit chamber 4 that can be used in the treatment system provided by this application includes at least the following two types: one is an aerated grit chamber, and the aeration is controlled by an air pipe on one side of the pond to make the sewage form The speed of the forward swirling flow (perpendicular to the direction of the water flow), this type of pool has a stable sand removal effect. The other is the swirling grit chamber 4 using hydraulic vortex desanding (the direction of the swirling flow is basically the same as that of the water flow), which has the advantages of simple pool type, small footprint, low operating cost, and good sand removal effect. The sand discharge of the swirl grit chamber 4 currently adopts two forms, one is sand discharge by sand pump, which has the advantage of less equipment and easy operation; the other is air lift sand discharge, which has the advantage of reliable and durable system, But the equipment is relatively more.

The grit chamber used in the processing system provided by the application is preferably the cyclone grit chamber 4, and its structure and working principle can be briefly described as follows in general: the cyclone type grit chamber desander is driven by the driving device, and the pond The rotation of the middle mixing impeller generates centrifugal force, so that the sand particles in the water are collected in the sand collection bucket at the bottom of the pool along the wall and the slope of the pool bottom, and at the same time, the organic matter adhered to the sand particles is separated. The sand collected in the sand bucket is lifted out of the pool by the air lift pump or self-priming sand pump for further separation of sand and water.

Usually, the size of the cyclone grit chamber 4 is designed according to the maximum flow of sewage. There is a slow agitator inside the cyclone grit chamber 4 to control the vortex to make the sand sink and suspend in the The organic matter in the water is discharged with the effluent, and the swirl agitator is driven by the gear motor on the working bridge on the top of the pool.

When using the swirl grit chamber 4 to wash the sand, the air or water flow scrubs the grit at the bottom to make it into a state of mortar so that the sand pump can discharge it and flush out the residual organic matter between the sand grains together. The scrubbed sand is pumped to the cyclone separator, then enters the sand-water separator for final sand-water separation, and then shipped out for disposal.

The urban sewage treated by the above-mentioned cyclone grit chamber 4 flows into the biochemical unit, and the microorganisms in the regeneration unit reduce COD, nitrogen and phosphorus, etc.

In the treatment system provided by this application, the biochemical unit utilizes microorganisms to undergo chemical reactions to realize chemical treatment of sewage.

The water inlet of the selective anaerobic tank 5 in the biochemical unit is connected with the water outlet of the cyclone grit chamber 4 . Selecting the anaerobic tank 5 can select dominant bacterial species for the subsequent process, enhance the biological nitrogen and phosphorus removal efficiency, and at the same time inhibit the excessive proliferation of filamentous bacteria and prevent sludge bulking. Select the anaerobic tank 5, also known as the biological selector, in which the typical dominant bacteria represented by phosphorus accumulating bacteria can gain an advantage in the competition with other bacteria under anaerobic conditions, thus forming an advantage in the subsequent process treatment , strengthen the effect of biological phosphorus removal, and at the same time inhibit the bulking of filamentous bacteria sludge.

The water inlet of the anaerobic pool 6 in the biochemical unit is connected to the water outlet of the selective anaerobic pool 5, and the anaerobic pool 6 utilizes the effect of anaerobic bacteria to hydrolyze, acidify and methanate the organic matter, remove the organic matter in the waste water, and Improving the biodegradability of sewage is beneficial to subsequent aerobic treatment. The anaerobic tank 6 is mainly used for anaerobic digestion. For sewage with high influent COD concentration, anaerobic reaction is usually carried out first to improve the removal rate of COD (Chemical Oxygen Demand, chemical oxygen demand), and to remove polymers that are difficult to degrade Organic matter is transformed into low-molecular organic matter that is easily degraded, and the ratio of BOD (Biochemical oxygen demand, biochemical oxygen demand) to COD is increased.

The anaerobic process can be divided into hydrolysis stage, acidification stage and methanation stage. The products of hydrolysis and acidification are mainly small molecular organic matter, which significantly increases the dissolved organic matter in wastewater. However, only soluble small molecular substances can directly enter the cells when microorganisms absorb organic matter, while insoluble macromolecular substances must first pass through extracellular enzymes. The decomposition can enter the metabolism of microorganisms. The hydrolysis process is relatively slow and affected by many factors at the same time, it is the rate-limiting stage of anaerobic degradation. In the stage of acidification, the small molecular compounds formed by the hydrolysis of the above-mentioned first stage are converted into simpler compounds in the cells of the fermenting bacteria, namely acidifying bacteria, and secreted out of the bacteria, mainly including volatile organic acids (VFA), lactol, Alcohols, etc., and then further converted into acetic acid, hydrogen, carbonic acid, etc. The acidification process is completed by a large number of fermentative bacteria and acetogenic bacteria, the vast majority of which are strictly anaerobic bacteria that can decompose sugars, amino acids and organic acids. In the anaerobic treatment process, the organic matter in the wastewater is finally converted into methane, carbon dioxide, water, hydrogen sulfide and ammonia through the joint action of a large number of microorganisms. The advantage of anaerobic digestion is that organic matter is digested to generate energy, and the residue can be used as fertilizer.

The RPIR pool 7 (Rapid Purification of sewage using sedimentation Integrated rectangular airlift loop Reactor, RPIR for short) in the biochemical unit is a rectangular airlift loop reactor for rapid purification and utilization of sewage and integrated sedimentation. The air-lift power is used to make the mixed liquid circulate, which greatly improves the oxygen transfer efficiency. The RPIR tank 7 used in the treatment system provided by this application includes a circulation clarifier module, referred to as "RPIR module", and the combination of the RPIR module and the aeration tank can be constructed to integrate circulation, reaction, separation, and automatic sludge return. High-efficiency biological sewage treatment device.

Referring to FIG. 2 , the RPIR tank 7 includes a tank body 71 , a plurality of aeration devices 73 , and a plurality of circulation clarifiers 74 . The pool body 71 includes an aerobic unit in vertical space. The aeration device can be a perforated tube aeration device, a microporous aeration device or a jet aeration device, etc. The interior of the circulation clarifier 74 includes a mud-water separation zone 75 .

The RPIR tank 7 is provided with a water inlet port, a water outlet port and a return port, the water inlet port is connected to the outlet end of the anaerobic tank 6, the water outlet port is connected to the secondary sedimentation tank 8, and the return port is connected to the anaerobic tank through the return flow of the mud-water mixture. 6 to connect to the return port to realize the return of the mud-water mixture.

The RPIR tank can remove pollutants such as organic matter and nitrate nitrogen in sewage, and at the same time realize the separation of mud and water. The mixed liquid has a stable flow state, good sludge properties, and excellent settling performance; strong nitrification and denitrification effects, excellent denitrification effect, and no sludge. The power is fully recirculated, and the energy saving effect is obvious.

Secondary settling tank 8 is a device for receiving biochemically treated effluent to settle biologically suspended solids to obtain clarified water. After biological treatment, the sewage must pass through the secondary settling tank 8 for mud-water separation. The function of the secondary settling tank 8 in the treatment system provided by this application is mainly to separate the sludge, to clarify, concentrate and return the activated sludge to the mixed solution, which can directly affect the effluent water quality and the return sludge concentration of the activated sludge system. The secondary settling tank 8 in this application not only separates sludge from water, but also concentrates sludge, and temporarily stores sludge due to changes in water volume and water quality.

The secondary sedimentation tank 8 is the secondary sedimentation tank. Generally speaking, the sedimentation tank includes five parts: the water inlet area, the sedimentation area, the buffer zone, the sludge area and the water outlet area. The function of the water inlet area and the water outlet area is to make the water flow evenly through the sedimentation tank, avoid the adverse effects of short flow and reduce turbulent flow on the sedimentation, reduce the dead water area, and improve the volume utilization rate of the sedimentation tank; the sedimentation area is also called clarification The sedimentation area is the working area of the sedimentation tank. In the sedimentation area, particles and sewage should be separated and precipitated; the sludge area is the area where sludge is stored, concentrated and discharged; the buffer zone is the water layer that separates the sedimentation area and the sludge area. Ensure that the particles that have settled will not float again due to the agitation of the water flow.

According to the direction of water flow, the sedimentation tank can be divided into three types: flat flow type, radial flow type and vertical flow type. Each sedimentation tank consists of five areas, namely the water inlet area, sedimentation area, buffer zone, sludge area and water outlet area.

The advantages of the advection sedimentation tank are: good sedimentation effect, strong adaptability to impact load and temperature change, simple construction, and low cost; the disadvantage is that the water distribution in the pool is not easy to be uniform, and when multiple buckets are used for sludge discharge, each bucket needs Separate mud discharge pipes are used to discharge mud separately, and the operation volume is large. When chain belt type mud scraper is used to discharge mud, the support parts and driving parts of the chain belt are immersed in water and are easy to rust. It is more suitable for areas with high groundwater level and poor geology and large, medium and small sewage treatment plants.

The advantages of the vertical flow sedimentation tank are: convenient sludge discharge, simple management, and small footprint; the disadvantages are: the depth of the pool is large, the construction is difficult, the applicability to impact load and temperature changes is poor, the cost is high, and the pool diameter should not be too large Large, otherwise the distribution of water will be uneven. It is suitable for small sewage treatment plants with a small amount of water.

The advantages of the radial flow sedimentation tank are: most of them are mechanical sludge discharge, with good operation, relatively simple management, and the sludge discharge equipment has become finalized; the disadvantages are: the mechanical sludge discharge equipment is complicated and requires high construction quality. It is suitable for areas with high groundwater level and large and medium-sized sewage treatment.

The urban sewage treated by the above-mentioned secondary settling tank 8 enters the air flotation device 9 to remove suspended solids in the water and improve water quality.

The air flotation device 9 in the treatment system provided by this application is to pass air into the water in the form of micro-bubbles, so that the micro-bubbles adhere to the particles suspended in the water to form a water-gas-particle three-phase mixed system, and the particles adhere to the air bubbles Finally, when the density is lower than that of water, it floats up to the water surface, forming a scum layer, which is separated from the water to achieve the purpose of removing suspended solids in the water and improving water quality.

The basic working principle of the air flotation device 9 is: air is introduced into the water to generate fine air bubbles, so that the fine suspended matter in the water adheres to the air bubbles, and floats to the water surface together with the air bubbles to form scum; the smaller the diameter of the air bubbles, the greater the number. The more, the better the effect of air flotation; inorganic salts in water will accelerate the bursting and merging of air bubbles, reducing the effect of air flotation; adding coagulant will promote the coagulation of suspended matter, making it stick to the air bubbles and float up; you can add flotation The selected agent converts the surface of the hydrophilic particles into a hydrophobic substance, which adheres to the air bubbles and floats up with the air bubbles.

The air flotation device 9 in this application can be an air flotation pool, that is, a pool structure that uses a large number of micro-bubbles to capture and adsorb fine particle stickies to float up to achieve the effect of solid-liquid separation. Its working principle is that part of the treated waste water circulates into the dissolved air tank. Under the state of pressurized air, the air is supersaturated and dissolved, and then mixed with the raw water added with flocculant at the entrance of the air flotation tank. Due to the pressure reduction, the supersaturated The air is released, forming tiny bubbles, which quickly attach to the suspended matter and lift it to the surface of the air flotation tank, thus forming a sludge floating layer that is easy to remove, and the heavier solid matter that settles at the bottom of the tank is also removed.

The above-mentioned air flotation tank includes a pool body, in which an aeration area, an air flotation area, a slag discharge area and a drainage area are sequentially formed in the pool body; a water inlet is set on the side wall of the aeration area, and an aerator is installed in the aeration area, and the top of the pool body A slag scraper is provided, a slag discharge port is provided on the side wall of the pool body, and a discharge port is provided on the side wall of the drainage area.

The urban sewage treated by the above-mentioned air flotation device 9 enters the filter cloth filter tank 10 . The water entering the filter cloth filter 10 enters the filter disc through the microporous filter cloth fixed on the hollow rotating shaft under the action of gravity pressure difference, the solid suspended matter is trapped outside the filter cloth, and the filtrate passes through the filter disc to the hollow rotating shaft. Converge and flow into the outlet tank, and discharge out of the filter through the outlet weir plate. In the filtration process, the sludge is adsorbed on the outside of the filter cloth, gradually forming a sludge layer. With the accumulation of sludge on the filter cloth, the filter resistance of the filter cloth increases, and the liquid level in the pool gradually rises. When the liquid level rises to the set value, the suction pump is turned on. The suction pump and transmission device make the filter disc rotate, and the cleaning device fixed on the outside of the filter cloth rubs against the surface layer of the filter cloth to scrape and suck away the silt on the surface layer of the filter cloth to complete the cleaning of the filter cloth. There is a sludge discharge pipe at the bottom of the pool, and according to the time setting, the sludge discharge pump is automatically activated to remove the sludge settled at the bottom of the pool.

A reverse suction pump can be arranged in the filter cloth filter tank 10, and when the negative pressure in the filter tank rises gradually, the water volume height in the tank is detected by a manometric measuring device. When the water level reaches the backwash preset value (high water level), the backsuction pump starts to start the intermittent backwashing process. When backwashing, the filter can continue to filter. During the filtration process, the filter disc is static, which helps the accumulation of sludge at the bottom of the tank. During backwashing, the filter disc rotates slowly. The suction pump sucks the surface of the filter cloth under negative pressure to remove the sludge particles accumulated on the filter cloth, and the water in the filter disc is sucked at the same time, and the water cleans the filter cloth from the inside out.

The water filtered by the filter cloth filter 10 flows into the contact disinfection tank 11 for disinfection, and the disinfectant is mixed with the treated sewage in the contact disinfection tank 11 to kill pathogenic microorganisms in the treated sewage. Commonly used disinfectants include NaClO, liquid chlorine, CaClO, etc., and their active ingredients are hypochlorite.

The main advantages of the contact disinfection pool 11 are: chlorine has a strong inactivation ability for bacteria; it can maintain a certain amount of residual chlorine in water for a long time, so it has continuous disinfection ability; the effect is reliable, easy to use, easy to store and transport, The cost is lower.

The water sterilized by the contact disinfection pool 11 can be discharged into the allocation pool 12, and the water outlet of the allocation pool 12 is connected with the reuse water pipe of the park, so that the reclaimed water after urban sewage treatment can be reused in the light pollution wastewater treatment system of the park, realizing water Resource reuse.

To sum up, this application provides a treatment system for realizing the reuse of urban sewage. After being treated by the treatment system, the urban sewage can be reused in the light-polluted wastewater treatment system of the industrial park to realize the reuse of water resources.

Embodiment two

Based on the treatment system for realizing urban sewage reuse provided in the first embodiment above, this embodiment provides a treatment process, which is based on the above-mentioned treatment system for realizing urban sewage reuse. Specifically, the treatment process includes Follow the steps below:

S1: Set coarse grille 1 in the irrigation canal for transporting urban sewage, and use coarse grille 1 to remove coarse suspended matter, floating matter, fibrous matter and solid particle matter that may block the water pump unit and pipeline valve;

S2: The water filtered by the coarse grid 1 is lifted by the lift pump 2 to the fine grid 3, and the fine grid 3 is used to remove the small floating and suspended matter in the sewage;

S3: The water filtered by the fine grid 3 is sent to the grit chamber to remove larger organic particles in the sewage;

S4: The water treated by the grit chamber is sent to the biochemical unit to reduce the chemical oxygen demand and nitrogen and phosphorus under the action of microorganisms;

S5: The sewage treated by the biochemical unit is sent to the secondary sedimentation tank 8 to realize the separation of mud and water;

S6: the supernatant of the secondary sedimentation tank 8 enters the air flotation device 9 to remove fine stickies;

S7: the effluent from the air flotation device 9 enters the filter cloth filter 10 to remove suspended matter;

S8: The effluent from the filter cloth filter 10 enters the contact disinfection tank 11, the effluent from the contact disinfection tank 11 enters the deployment pool 12, and the water in the deployment pool 12 is reused for the light pollution wastewater treatment system in the park.

In the above-mentioned step S4, the biochemical unit includes the selected anaerobic tank 5, the anaerobic tank 6, the RPIR tank 7 and the secondary sedimentation tank 8 connected in sequence, and the selective anaerobic tank 5 and the secondary sedimentation tank 8 are all connected to the inlet of the return sludge pump 13 The outlet of the return sludge pump 13 is connected to the sludge storage tank 14, and the sludge storage tank 14 is connected to the sewage plant in the park; the anaerobic tank 6 and the RPIR tank 7 form an internal return flow.

The treatment process for realizing the reuse of urban sewage provided by this application can carry out the whole process of urban sewage treatment, realize the resource utilization of urban reclaimed water, and dilute industrial wastewater to a certain extent, reducing the difficulty of industrial wastewater treatment.

The technical features of the above embodiments can be combined arbitrarily (as long as there is no contradiction in the combination of these technical features), for the sake of concise description, all possible combinations of the various technical features in the above embodiments are not described; these are not clear All the written examples should also be regarded as within the scope of the description in this specification.

The present application has been described more specifically and in detail through general descriptions and specific examples above. It should be understood that based on the technical concept of the present application, some conventional adjustments or further innovations can also be made to these specific embodiments; Also fall within the protection scope of the claims of the present application.

Claims (10)

1. A treatment system that realizes urban sewage reuse, is characterized in that, comprises coarse grid, fine grid, grit chamber, biochemical unit, secondary settling tank, air flotation device, filter cloth filter tank, contact disinfection tank and Deployment pool; wherein, the coarse grid is set in the irrigation canal used to transport urban sewage; the sewage filtered through the coarse grid flows through the fine grid for secondary filtration; filtered through the fine grid The final sewage flows into the grit chamber, the grit chamber is provided with a stirring impeller, and the bottom of the grit chamber is provided with a sand bucket; , RPIR tank and secondary settling tank, select anaerobic tank and secondary settling tank to be connected with the inlet of the return sludge pump; anaerobic tank and RPIR tank are connected by pipelines to form mud-water mixture backflow; the outlet of the grit chamber is connected to the The water inlet of the selective anaerobic tank is connected; the water outlet of the secondary sedimentation tank is connected with the water inlet of the air flotation device; the water outlet of the air flotation device is connected with the filter cloth filter, and the filter cloth filter, contact The disinfection pool and the deployment pool are connected in sequence; the deployment pool is provided with a water outlet port adapted to the reuse water pipe of the park. 2. The treatment system for realizing urban sewage reuse according to claim 1, characterized in that, the coarse grid comprises a frame and one or more groups of mutually parallel metal grating bars installed on the frame, and the metal gratings A plurality of grids are formed on the grid bars; the coarse grids are obliquely arranged in irrigation channels for transporting urban sewage; The fine grid includes a frame and one or more sets of parallel metal grid bars installed on the frame, and several grids are formed on the metal grid bars; The sewage filtered by the coarse grid is lifted to the water inlet side of the fine grid by the lifting pump. 3. The treatment system for realizing urban sewage reuse according to claim 1, wherein the grit chamber is a swirl grit chamber, and the bottom of the swirl grit chamber forms a sand collecting bucket, A stirring impeller is arranged in the pool, and when the stirring impeller rotates, the sand particles in the water are collected in the sand collection bucket along the pool wall and the slope of the bottom of the pool, and the organic matters adhered to the sand particles are separated; An air lift pump or a self-priming sand pump that discharges the sand in the sand collection hopper. 4. The treatment system for realizing urban sewage reuse according to claim 1, wherein the water inlet of the selected anaerobic tank is connected to the water outlet of the swirl grit chamber, and the outlet of the selected anaerobic tank is The water inlet is connected with the water inlet of the anaerobic pool, and anaerobic bacteria are placed in the anaerobic pool; the RPIR pool is provided with a water inlet port and a water outlet port, and the water inlet port is connected with the water outlet of the anaerobic pool, and the water outlet port is connected with the two The settling tank is connected, and the RPIR tank is connected with the anaerobic tank through the mud-water mixture return flow communication pipeline. 5. The treatment system for realizing urban sewage reuse according to claim 1 or 4, wherein the RPIR pond comprises a pond body, a plurality of aeration devices, and a plurality of circulation clarifiers; An aerobic unit is arranged in the vertical space, and a mud-water separation zone is arranged inside the circulation clarifier. 6. The treatment system realizing urban sewage reuse according to claim 1, characterized in that, said secondary settling tank comprises a pool body, and in the pool body, an intake area, a sedimentation area, a buffer zone, a sludge area and water area. 7. The treatment system for realizing urban sewage reuse according to claim 1, wherein the air flotation device comprises a pool body, and an aeration area, an air flotation area, a slag discharge area and a drainage area are sequentially formed in the pool body; A water inlet is set on the side wall of the aeration area, an aerator is installed in the aeration area, a slag scraper is installed on the top of the pool body, a slag discharge port is set on the side wall of the pool body, and a drain port is set on the side wall of the drainage area. 8. The treatment system for realizing urban sewage reuse according to claim 1, wherein a hollow rotating shaft is arranged in the filter cloth filter tank, a filter cloth and a filter disc are arranged on the hollow rotating shaft, and the filter cloth enters the filter cloth to filter Under the action of gravity pressure difference, the water in the pool passes through the small holes in the filter cloth and enters the filter disc, the solid suspended matter is trapped outside the filter cloth, and the filtrate converges into the hollow rotating shaft through the filter disc and flows into the outlet tank. Discharge the filter cloth filter through the outlet weir plate. 9. The treatment system for realizing urban sewage reuse according to claim 1, wherein a disinfectant is added to the sewage in the contact disinfection tank, and the disinfectant contains hypochlorite; The reuse water pipe of the park is connected with the light pollution wastewater treatment system of the park. 10. A treatment process for realizing urban sewage reuse, characterized in that, the treatment system for realizing urban sewage reuse as claimed in claim 1 comprises the steps of: S1: Set up coarse screens in the irrigation canals that transport urban sewage, and use the coarse screens to remove coarse suspended matter, floating matter, fibrous matter and solid particulate matter; S2: The water filtered by the coarse screen is lifted to the fine screen, and the fine screen is used to remove the small floating and suspended matter in the sewage; S3: The water filtered by the fine grid is transported to the grit chamber to remove larger organic particles in the sewage; S4: The water treated by the grit chamber is sent to the biochemical unit to reduce the chemical oxygen demand and nitrogen and phosphorus under the action of microorganisms; S5: The sewage treated by the biochemical unit is sent to the secondary settling tank to realize the separation of mud and water; S6: The supernatant of the secondary sedimentation tank enters the air flotation device to remove fine stickies; S7: The effluent from the air flotation device enters the filter cloth filter to remove suspended matter; S8: The effluent from the filter cloth filter enters the contact disinfection tank, the effluent from the contact disinfection tank enters the deployment pool, and the water in the allocation pool is reused for the light pollution wastewater treatment system in the park.