Biochemical pool low-cost dosing phosphorus removal and biological selection treatment device

Abstract

The utility model relates to the technical field of sewage treatment, in particular to a biochemical pool low-cost dosing dephosphorization and biological selection treatment device which comprises a biochemical pool and a pre-sedimentation pool, the pre-sedimentation pool is separated from the biochemical pool through a partition plate, a water passing hole is formed in the partition plate, and the biochemical pool and the pre-sedimentation pool are communicated through the water passing hole; a sludge return pump and a sludge return pipe are arranged at the bottom of the pre-sedimentation tank, the sludge return pump is arranged on the sludge return pipe, and sludge is returned to the front end of the biochemical tank through the sludge return pipe; a phosphorus removal agent adding point is arranged at the water outlet end of the pre-sedimentation tank, a water outlet is formed in the rear end of the pre-sedimentation tank, and the water outlet is connected with the MBR tank or the secondary sedimentation tank through a pipeline. A water tank is separated from the tail end of an aerobic tank and is used as a biochemical pre-sedimentation tank, so that beneficial strain sludge in a biochemical tank is settled at the water tank, and meanwhile, a sludge reflux pump is additionally arranged at the bottom of the water tank for settling sludge, so that the sludge flows back to the front end of the biochemical tank, and the sludge concentration of the biochemical tank is ensured.

Description

Technical Field

[0001] This utility model relates to the field of wastewater treatment technology, and in particular to a low-cost chemical dosing and phosphorus removal and biological selection treatment device for a biological treatment tank. Background Technology

[0002] In wastewater treatment processes, A / O+MBR (or secondary sedimentation tank) is a widely used technology combination for removing pollutants such as organic matter, nitrogen, and phosphorus from wastewater. However, in practical applications, this process often lacks a dedicated tertiary sedimentation tank for phosphorus reduction, making it difficult to consistently achieve the required total phosphorus (TP) concentration in the effluent below 0.5 mg / L. To address this issue, see [link to relevant documentation]. Figure 3 and Figure 4 Current technology typically involves adding a phosphorus removal agent at the inlet of an MBR (or secondary sedimentation tank) to control the TP concentration in the effluent.

[0003] While the above methods can meet effluent requirements to some extent, they still have some limitations in actual operation. First, due to the large amount of sludge in the biological treatment tank, the dosage of phosphorus removal agent is often high, but only 10%-20% of the agent actually participates in the phosphorus removal reaction, while the remaining 80%-90% mainly participates in the coagulation reaction, resulting in waste of the agent. For example, under normal operating conditions, the dosage of PAC agent may be as high as 100 ppm.

[0004] Secondly, the sludge concentration in the biological treatment tank increases significantly after the addition of phosphorus removal agent. Under normal circumstances, the sludge concentration in the aerobic biological treatment tank is 3000-5000 mg / L, but after adding the phosphorus removal agent, the sludge concentration may reach 10000-15000 mg / L. This high sludge concentration has a significant impact on subsequent processes: when the aerobic downstream process is an MBR process, excessively high sludge concentration leads to increased membrane filtration load, exacerbated fouling, and a reduction in membrane cleaning frequency from the recommended 3-6 months to 1-2 months; when the aerobic downstream process is a secondary sedimentation tank, excessive sludge flux may cause sludge overflow in the secondary sedimentation tank.

[0005] Furthermore, the addition of phosphorus removal agents significantly increases the total amount of sludge in the biological treatment tank, leading to more frequent sludge discharge and placing higher demands on the sludge treatment equipment. This not only increases sludge treatment costs but also raises the cost of sludge transportation and disposal. Simultaneously, the introduction of a large amount of inorganic sludge through the addition of phosphorus removal agents significantly increases the proportion of ineffective sludge in the biological treatment tank. MLSS (Mixed Liquor Suspended Solids Concentration) consists of MVLSS (Mixed Liquor Volatile Suspended Solids Concentration) and the concentration of ineffective inorganic sludge; therefore, an increase in MLSS concentration reduces the MVLSS / MLSS ratio. During the process of reducing sludge load through sludge discharge, the concentration of beneficial bacteria (MVLSS) in the biological treatment tank may decrease accordingly, thereby weakening the biochemical treatment effect on pollutants.

[0006] In summary, existing technologies have room for improvement in terms of reagent dosing efficiency, sludge load control, sludge treatment cost, and biochemical treatment effectiveness.

[0007] In view of this, the present invention provides a low-cost chemical dosing and phosphorus removal and biological selection treatment device for biological ponds. Utility Model Content

[0008] The purpose of this invention is to address the shortcomings of existing technologies by providing a low-cost phosphorus removal and biological selection treatment device for biological treatment tanks. This device reduces the concentration of suspended solids in wastewater to decrease the actual dosage of phosphorus removal agents, while optimizing the microbial community structure within the biological treatment tank. This reduces the sludge load in subsequent process stages, improves the stability of effluent quality, and lowers sludge treatment costs.

[0009] To solve the above technical problems, the following technical solution is adopted:

[0010] A low-cost phosphorus removal and biological selection treatment device for a biological treatment tank includes a biological treatment tank and a pre-sedimentation tank. The pre-sedimentation tank is separated from the biological treatment tank by a partition plate with water passage holes connecting the biological treatment tank and the pre-sedimentation tank. The bottom of the pre-sedimentation tank is equipped with a sludge return pump and a sludge return pipe. The sludge return pump is installed on the sludge return pipe and returns sludge to the front end of the biological treatment tank through the sludge return pipe. The effluent end of the pre-sedimentation tank is equipped with a phosphorus removal agent dosing point, and the rear end of the pre-sedimentation tank is equipped with an outlet. The outlet is connected to an MBR tank or a secondary sedimentation tank through an overflow outlet.

[0011] Furthermore, the sludge return pipe is made of stainless steel and is connected to the external sludge discharge system via a flange.

[0012] Furthermore, the pre-sedimentation tank is formed by dividing the end of the biological treatment tank into a water pool.

[0013] Furthermore, the bottom of the pre-sedimentation tank is provided with a conical sludge collection hopper, the conical angle of which is 50 to 60 degrees, the inner wall surface of which is smoothed, and the bottom of which is welded and sealed to the sludge return pipe.

[0014] Furthermore, the partition is provided with multiple rectangularly distributed water passage holes, each 100mm × 100mm in size and spaced 200mm apart; the partition is made of carbon steel plate with a thickness of 5-10mm or an additional concrete partition wall is added.

[0015] The above technical solution has the following beneficial effects:

[0016] 1. Reduced dosage of phosphorus removal agent. This utility model patent can reduce the concentration of suspended solids in wastewater from 5000mg / L-12000mg / L to 300mg / L-500mg / L, greatly reducing the amount of phosphorus removal agent required.

[0017] 2. The load of subsequent treatment processes is greatly reduced, which can improve the quality of effluent and ensure more stable operation of subsequent processes. (1) When the subsequent process is MBR, the concentration of sludge entering the MBR tank is reduced, the flux of the MBR membrane increases, and the frequency of MBR membrane cleaning is reduced to once every 3-6 months, which can ensure more stable operation of the MBR process. (2) When the subsequent process is secondary sedimentation tank, the concentration of sludge entering the secondary sedimentation tank decreases, the sedimentation effect is better, the risk of sludge runoff in the effluent is greatly reduced, the sedimentation operation is more stable, and the effluent quality is better.

[0018] 3. The amount of sludge is greatly reduced. The original dosage of phosphorus removal agent was 100-200 ppm, which produced a lot of sludge. After optimization, the dosage of phosphorus removal agent is only 10-20 ppm, which greatly reduces the amount of sludge produced.

[0019] 4. The total sludge concentration in the biological treatment tank is reduced, while the proportion of effective bacteria is greatly increased, resulting in specific biological selection advantages. Normal sludge concentration is 3000-5000 mg / L. The original method of adding phosphorus removal agents would result in a total sludge concentration of 10000-15000 mg / L, with the vast majority of the sludge being ineffective physicochemical sludge, and the actual proportion of effective bacteria in the sludge being very low. Pre-sedimentation allows for the selective screening of effective bacteria in the sludge, significantly increasing the MLVSS / MLSS ratio.

[0020] 5. A water tank is separated at the end of the aerobic tank to be used as a biological pre-sedimentation tank, so that the beneficial bacteria sludge with good settling effect in the biological tank can settle here. At the same time, a sludge return pump is added to the bottom of the settled sludge here to return the sludge to the front end of the biological tank to ensure the sludge concentration of the biological tank. Attached Figure Description

[0021] The present invention will be further described below with reference to the accompanying drawings:

[0022] Figure 1 This is a schematic diagram of the structure of a low-cost chemical dosing and phosphorus removal and biological selection treatment device for a biological treatment pond according to Embodiment 1 of this utility model.

[0023] Figure 2 This is a schematic diagram of the structure of a low-cost chemical dosing and phosphorus removal and biological selection treatment device for a biological pond, according to Embodiment 2 of this utility model.

[0024] Figure 3 This is a schematic diagram of the structure of a low-cost chemical dosing phosphorus removal and biological selection treatment device for a biological pond, which is an embodiment of the prior art.

[0025] Figure 4 This is a schematic diagram of the structure of a low-cost chemical dosing phosphorus removal and biological selection treatment device for a biological pond, which is an embodiment 2 of the prior art.

[0026] In the diagram: 1-Biological treatment tank; 2-Pre-sedimentation tank; 3-Baffle plate; 4-Sludge return pump; 5-Sludge return pipe; 6-Phosphorus removal agent dosing point; 7-MBR tank; 8-Secondary sedimentation tank; 9-Conical sludge collection hopper. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. However, it should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of the present utility model. Furthermore, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessarily obscuring the concept of the present utility model.

[0028] Example 1, see Figure 1 A low-cost phosphorus removal and biological selection treatment device for biological treatment includes a biological treatment tank 1 and a pre-sedimentation tank 2. The pre-sedimentation tank 2 is separated from the biological treatment tank 1 by a partition 3. The partition 3 is provided with water passage holes, which connect the biological treatment tank 1 and the pre-sedimentation tank 2. The design of the water passage holes in the partition 3 of the pre-sedimentation tank 2 allows suspended solids in the mixed liquor of the biological treatment tank 1 to settle initially in the pre-sedimentation tank 2, reducing the concentration of suspended solids in the wastewater entering the phosphorus removal agent dosing point from 5000-12000 mg / L to 300-500 mg / L, thereby reducing ineffective coagulation reaction between the phosphorus removal agent and the suspended solids.

[0029] Furthermore, the bottom of the pre-sedimentation tank 2 is equipped with a sludge return pump 4 and a sludge return pipe 5. The sludge return pump 4 is installed on the sludge return pipe 5, through which sludge is returned to the front end of the biological treatment tank 1. The sludge return to the front anaerobic zone of the biological treatment tank 1 can maintain the activated sludge concentration (MLSS 3000-5000 mg / L) in the biological treatment tank 1, avoid excessively high sludge concentration due to the addition of phosphorus removal agent (existing technology can reach 10000-15000 mg / L), increase the proportion of volatile suspended solids in the mixed liquor (MLVSS / MLSS≥60%), and enhance the treatment efficiency of microorganisms for pollutants.

[0030] The pre-sedimentation tank 2 has a phosphorus removal agent dosing point 6 at its effluent outlet, and an outlet at its rear end, which is connected to the MBR tank 7 via an overflow outlet. Positioning the phosphorus removal agent dosing point 6 at the effluent outlet of the pre-sedimentation tank 2 reduces the dosage from 100-200 ppm in existing technologies to 10-20 ppm (saving 80%-90%), while also reducing the membrane filtration load on the subsequent MBR tank (extending membrane cleaning frequency from once every 1-2 months to once every 3-6 months) or the risk of sludge runoff in the secondary sedimentation tank.

[0031] Furthermore, the sludge return pipe 5 is made of 304 stainless steel and is connected to the external sludge discharge system through a flange connection structure to ensure the corrosion resistance of the pipeline and the convenience of installation and maintenance.

[0032] Furthermore, the pre-sedimentation tank 2 is directly separated from the end of the biochemical tank 1 by a 5-10mm thick carbon steel plate partition 3, eliminating the need for an additional independent tank and saving infrastructure costs and floor space.

[0033] Furthermore, the bottom of the pre-sedimentation tank 2 is provided with a conical sludge collection hopper 9, the conical angle of the conical sludge collection hopper 9 is 50 degrees to 60 degrees, the inner wall surface of the conical sludge collection hopper is smoothed, and the bottom of the conical sludge collection hopper is sealed with argon arc welding to ensure connection strength and sealing performance.

[0034] Furthermore, a stirring device is provided below the phosphorus removal agent addition point 6. The stirring device includes a stirring motor and stirring blades. The output end of the stirring motor is provided with a stirring shaft, and the stirring blades are provided on the stirring shaft. The speed range of the stirring motor is 30r / min to 60r / min. The stirring blades are made of corrosion-resistant stainless steel, and the blades are arc-shaped with a diameter of 200mm to 300mm.

[0035] Furthermore, the pre-sedimentation tank 2 is equipped with a guide plate, which is inclined at an angle of 45° to 60° with the horizontal plane. It is made of 5mm thick acid and alkali resistant PVC material (resistant to pH 2-12), and the surface is sanded (roughness Ra3.2-6.3μm) to enhance the water flow disturbance effect.

[0036] Furthermore, the deflector is made of 5mm thick PVC material, and the surface of the deflector is treated with an anti-slip coating.

[0037] Furthermore, the partition 3 is provided with a plurality of rectangularly distributed water passage holes, the size of which is 100mm×100mm and the spacing is 200mm; the edges of the water passage holes are provided with rubber sealing rings, and the partition 3 is made of carbon steel plate with a thickness of 5-10mm or a concrete partition wall is added.

[0038] This invention separates a water tank at the end of the aerobic tank, which is used as a biological pre-sedimentation tank 2, so that the beneficial bacteria sludge in the biological tank 1 can settle here. At the same time, a sludge return pump 4 is added to the bottom of the settled sludge here to return the sludge to the front end of the biological process, so as to ensure the sludge concentration of the biological tank 1.

[0039] The surface loading of the pre-sedimentation tank 2 in this invention can be appropriately higher, specifically around 1.5m. 3 / (m 2 .h)-5m 3 / (m 2 Under high load operation, the pre-sedimentation tank 2 has a very good sludge settling effect with the dominant bacterial species, and it can be directly returned by adding a sludge return pump 4. The poor sludge has a poor settling effect, and under high load operation of the pre-sedimentation tank 2, it can be directly entered into the subsequent process section (MBR or secondary sedimentation tank). Long-term operation in this way can achieve the purpose of optimizing and screening the microorganisms in the biological tank 1.

[0040] This invention adds a phosphorus removal agent dosing point 6 at the effluent end of the high-load pre-sedimentation tank 2. After sedimentation in the high-load pre-sedimentation tank 2, the sludge concentration is greatly reduced. The original sludge concentration in the biological treatment tank 1 is 5000mg / L-12000mg / L. After high-load pre-sedimentation, the sludge concentration in the wastewater can be controlled at 300mg / L-500mg / L. At this time, after adding phosphorus removal agent, the proportion of the agent participating in the phosphorus removal reaction will increase significantly. Because the sludge concentration in the water is low, the actual phosphorus removal agent dosage can be controlled at 10-20ppm, which is far lower than the existing 100ppm. This can save on phosphorus removal agent dosing costs and better control the TP removal effect in the effluent.

[0041] See Figure 2 The difference from Embodiment 1 is that the outlet is connected to the secondary sedimentation tank 8 by setting an overflow outlet.

[0042] The above are merely specific embodiments of this utility model, but the technical features of this utility model are not limited thereto. Any simple changes, equivalent substitutions, or modifications made based on this utility model to solve essentially the same technical problems and achieve essentially the same technical effects are all covered within the protection scope of this utility model.

Claims

1. A low-cost chemical dosing and biological selection treatment device for a biological treatment pond, characterized in that: The system includes a biological treatment tank and a pre-sedimentation tank, characterized in that: the pre-sedimentation tank is separated from the biological treatment tank by a partition, the partition having water passage holes through which the biological treatment tank and the pre-sedimentation tank are connected; the bottom of the pre-sedimentation tank is equipped with a sludge return pump and a sludge return pipe, the sludge return pump being installed on the sludge return pipe, through which sludge is returned to the front end of the biological treatment tank; the effluent end of the pre-sedimentation tank is equipped with a phosphorus removal agent dosing point, and the rear end of the pre-sedimentation tank is equipped with an effluent outlet, the effluent outlet being connected to an MBR tank or a secondary sedimentation tank via an overflow outlet.

2. The treatment device for low-cost chemical dosing for phosphorus removal and biological selection in a biological treatment pond according to claim 1, characterized in that: The sludge return pipe is made of stainless steel and is connected to the external sludge discharge system via a flange.

3. The treatment device for low-cost chemical dosing for phosphorus removal and biological selection in a biological treatment pond according to claim 1, characterized in that: The pre-sedimentation tank is formed by dividing the end of the biological treatment tank into a water pool.

4. The treatment device for low-cost chemical dosing for phosphorus removal and biological selection in a biological treatment pond according to claim 1, characterized in that: The bottom of the pre-sedimentation tank is equipped with a conical sludge collection hopper with a cone angle of 50 to 60 degrees. The inner wall surface of the conical sludge collection hopper is smoothed, and the bottom of the conical sludge collection hopper is welded and sealed to the sludge return pipe.

5. The treatment device for low-cost chemical dosing for phosphorus removal and biological selection in a biological treatment pond according to claim 1, characterized in that: The partition is provided with multiple rectangularly distributed water passage holes, each 100mm × 100mm in size and spaced 200mm apart. The partition is made of carbon steel plate with a thickness of 5-10mm or is made of additional concrete partition wall.

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