Activated sludge filtering type secondary sedimentation tank adaptive device

Abstract

The invention provides an activated sludge filtering type secondary sedimentation tank adaptive device, which relates to the technical field of sewage treatment and comprises a biochemical tank, a delivery pump, an activated sludge filtering device and a secondary sedimentation tank, the activated sludge filtering device can be a rotating disc type filtering device or a mesh belt type filtering device and can be externally arranged between the biochemical tank and the secondary sedimentation tank, and the rotating disc type filtering device can also be embedded at the tail end in the biochemical tank. The activated sludge at the tail end of the biochemical pool is pressurized and conveyed to an activated sludge filtering device through a conveying pump, after the activated sludge is subjected to solid-liquid separation, filtered water can flow into a secondary sedimentation tank, and the intercepted activated sludge can return to the front end of the biochemical pool to participate in the biochemical reaction again. By intercepting part of activated sludge in advance, the solid load of the secondary sedimentation tank can be reduced, and the actual treatment capacity of the secondary sedimentation tank is improved; the device effectively solves the problem that the built sewage treatment plant is difficult to expand in situ due to overhigh solid load of the secondary sedimentation tank, is adaptive to different site conditions, and is low in improvement cost and high in practicability.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, and in particular to an adapter for an activated sludge filtration type secondary sedimentation tank. Background Technology

[0002] In urban wastewater treatment processes, the secondary sedimentation tank is a core structure connecting the biological treatment unit and the effluent discharge unit. Its main function is to separate the activated sludge discharged from the biological treatment tank from the treated water, ensuring that the final effluent suspended solids concentration meets standards. In the early days of wastewater treatment plant design, the industry generally used surface loading as the core design parameter for secondary sedimentation tanks. This design approach primarily focused on "water treatment capacity," neglecting the crucial impact of solids loading on sedimentation efficiency. With the development of the wastewater treatment industry and changes in operating conditions, this design flaw has gradually led to a series of technical problems, causing the secondary sedimentation tank to become a major performance bottleneck in existing wastewater treatment plants, specifically in the following two aspects: On the one hand, rapid urbanization has driven a continuous increase in the discharge of domestic sewage. The actual amount of sewage treated by the secondary sedimentation tank has gradually approached or exceeded the original design load, resulting in a significant increase in the solid load within the secondary sedimentation tank. When the solid load exceeds the carrying capacity threshold of the secondary sedimentation tank, the increased concentration of suspended solids in the effluent from the biological treatment tank will disrupt the original design sedimentation kinetic balance, leading to a decrease in the target sedimentation efficiency. In some cases, it may even result in difficulties in sludge layer compression and poor sedimentation effects such as effluent carrying sludge flocs, directly affecting the stability of the effluent quality from the secondary sedimentation tank.

[0003] On the other hand, in recent years, national and local governments have successively raised wastewater treatment discharge standards, with most regions adding mandatory requirements for total nitrogen (TNI) in effluent. To meet the TNI removal requirements, wastewater treatment plants need to increase the mixed liquor suspended solids (MLSS) concentration in the biological treatment tank; and enhance the efficiency of denitrification by increasing the amount of microorganisms in the activated sludge. However, the increase in MLSS directly leads to an increase in the total suspended solids in the effluent from the biological treatment tank, further exacerbating the solids load pressure on the secondary sedimentation tank, creating a contradiction between the increased discharge standards and the insufficient carrying capacity of the secondary sedimentation tank. In addition, for existing wastewater treatment plants, if on-site expansion is required to address the above problems, the modification of the secondary sedimentation tank faces significant limitations: since the tank structure, tank volume layout, and surrounding pipelines of the secondary sedimentation tank are fixed during construction, it is difficult to expand its solids load capacity through simple modifications, resulting in high construction difficulty, long modification period, and high cost for on-site expansion projects.

[0004] In summary, how to effectively reduce the solid load in the secondary sedimentation tank of sewage treatment plants and alleviate its load-bearing pressure has become a technical pain point that the sewage treatment industry urgently needs to overcome. Summary of the Invention

[0005] The purpose of this invention is to provide an adapter for activated sludge filtration-type secondary sedimentation tanks, thereby solving the problems existing in the prior art and effectively reducing the solid load in the secondary sedimentation tanks of wastewater treatment plants, alleviating the pressure on the secondary sedimentation tanks. To achieve the above objective, this invention provides the following solution: an adapter for activated sludge filtration-type secondary sedimentation tanks, comprising: A biological treatment tank, comprising a tank body and a sludge return inlet for receiving returned sludge, the sludge return inlet being connected to the tank body; An activated sludge filtration assembly is provided with an inlet, a filtrate outlet, and a sludge interception outlet. The inlet is connected to the biological treatment tank via a pipe, and the sludge return inlet of the biological treatment tank is connected to the sludge interception outlet via a pipe. The filtrate outlet of the activated sludge filtration component is connected to the secondary sedimentation tank or the qualified water discharge network via a pipeline.

[0006] As one embodiment, it also includes a transfer pump, the inlet of which is connected to the body of the biological treatment tank via a pipe, and the outlet of which is connected to the inlet of the activated sludge filter assembly via a pipe.

[0007] As one embodiment, the activated sludge filtration assembly is disposed between the biological treatment tank and the secondary sedimentation tank.

[0008] In one embodiment, the activated sludge filter assembly is embedded in the end chamber of the biological treatment tank; the inlet of the activated sludge filter assembly is connected to the end chamber of the biological treatment tank; and the sludge discharge outlet of the activated sludge filter assembly is connected to the front end of the biological treatment tank through a pipe.

[0009] As one embodiment, the activated sludge filtration assembly includes a rotary disc filter and a mesh belt filter; the rotary disc filter includes a support, a porous disc rotatably mounted on the support, and a matching backwashing assembly; the mesh belt filter includes a frame and a filter mesh belt tensioned on the frame.

[0010] In one embodiment, the rotary filter is disposed between the biological tank and the secondary sedimentation tank; the inlet of the rotary filter is connected to the end of the biological tank; the filtrate outlet of the rotary filter is connected to the secondary sedimentation tank; and the sludge discharge outlet of the rotary filter is connected to the front end of the biological tank.

[0011] In one embodiment, the mesh belt filter is disposed between the biological treatment tank and the secondary sedimentation tank; the inlet of the mesh belt filter is connected to the end of the biological treatment tank; the filtrate outlet of the mesh belt filter is connected to the secondary sedimentation tank; and the sludge discharge outlet of the mesh belt filter is connected to the front end of the biological treatment tank.

[0012] In one embodiment, the rotary filter is installed in the end chamber of the biological treatment tank; the inlet of the rotary filter is connected to the end chamber of the biological treatment tank; the filtrate outlet of the rotary filter is connected to the secondary sedimentation tank through a pipe; and the sludge discharge outlet of the rotary filter is connected to the front end of the biological treatment tank through a pipe.

[0013] As one implementation, the outlet of the biological treatment tank is only connected to the rotary filter device; the rotary filter device is provided with a sludge interception outlet; the sludge interception outlet is connected to two branches, the first branch is connected to the inlet mixing zone at the front of the biological treatment tank, the second branch is connected to the sewage treatment device, and the filtrate outlet of the rotary filter device is connected to the qualified water discharge pipeline network.

[0014] In one embodiment, the inlet of the mesh belt filter is connected to the biological tank; the end of the biological tank is also provided with an outlet pipe connected to the secondary sedimentation tank; the sludge discharge outlet of the mesh belt filter is connected to the sludge treatment device through a sludge discharge pipe, and the filtrate outlet of the mesh belt filter is connected to the front end of the biological tank through a return pipe.

[0015] The present invention achieves the following technical effects compared to the prior art: 1. The activated sludge filtration component of this invention can perform solid-liquid separation of activated sludge in the biological treatment tank, pre-retaining a portion of the solid sludge and only transporting the filtrate after removing suspended solids to the secondary sedimentation tank. This directly reduces the total amount of solids entering the secondary sedimentation tank, alleviating the solid load pressure caused by the increase in wastewater volume and preventing a decrease in sedimentation efficiency. On the other hand, the retained activated sludge is returned to the biological treatment tank 1 through the sludge return inlet, which can maintain or even increase the MLSS concentration in the tank to meet the total nitrogen removal requirements without increasing the total amount of suspended solids in the effluent from the biological treatment tank, ensuring the stable operation of the effluent quality and the secondary sedimentation tank. At the same time, the activated sludge filtration component only needs to be connected to the existing biological treatment tank and the secondary sedimentation tank through pipelines, without dismantling or modifying the fixed secondary sedimentation tank structure, making it suitable for in-situ modification scenarios.

[0016] Other technical solutions of the present invention have also achieved the following technical effects: 2. The technical solutions of the five embodiments of the present invention effectively solve the core problems of excessive load and insufficient biochemical efficiency in the secondary sedimentation tanks of existing sewage treatment plants through "targeted filtration design and sludge recycling," significantly improving the stability and adaptability of the treatment system. On the one hand, each embodiment uses a rotary or mesh belt filter to perform solid-liquid separation of the effluent from the biological treatment tank in advance: Examples 1, 2, and 3 use a diversion mode to intercept part of the activated sludge or large-particle impurities, directly reducing the solid load entering the secondary sedimentation tank and avoiding a decrease in sedimentation effect due to overload; Example 4 replaces the secondary sedimentation tank with full-volume filtration, allowing the filtrate to be discharged directly in compliance with standards, completely avoiding the difficulties of secondary sedimentation tank modification; Example 5 further uses a mesh belt to intercept large-particle inorganic matter, enhancing the efficiency of microbial degradation. At the same time, except for Example 5 which sends the intercepted impurities to sludge treatment, the other embodiments return the intercepted activated sludge to the front end of the biological treatment tank, which reduces sludge loss and maintains a stable MLSS concentration in the tank, meeting the microbial quantity required for total nitrogen removal.

[0017] 3. The solutions of this invention possess strong adaptability to various scenarios and are economically viable for upgrades, significantly reducing the difficulty and cost of upgrading existing wastewater treatment plants. From a layout perspective, Examples 1 and 2 employ external filtration devices, requiring no alteration to the existing biological treatment tank and secondary sedimentation tank structure; upgrades can be achieved simply through pipe connections. Example 3 integrates a rotary device at the end of the biological treatment tank, saving ground space, making it particularly suitable for the compact sites of small and medium-sized wastewater treatment plants. Regarding flexibility in modification, when using a mesh belt device instead of a rotary device in Example 2, the original installation location and piping can be reused, avoiding additional adjustments. The overall solution does not require large-scale dismantling and reconstruction, allowing for flexible selection based on the wastewater treatment plant's site conditions, treatment needs, and upgrade targets, achieving the dual benefits of "low-cost upgrade and high-efficiency operation." Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram illustrating the layout principle of Example 1 of the present invention; Figure 2 This is a schematic diagram of the layout principle of Example 2 of the present invention; Figure 3 This is a schematic diagram of the layout principle of Example 3 of the present invention; Figure 4 This is a schematic diagram of the layout principle of Example 4 of the present invention; Figure 5 This is a schematic diagram of the layout principle of Example 5 of the present invention.

[0020] Among them, 1. biological treatment tank; 2. transfer pump; 4. secondary sedimentation tank; 31. rotary filter device; 32. mesh belt filter device. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0023] This embodiment provides an adapter for an activated sludge filtration type secondary sedimentation tank. Please refer to [link / reference]. Figure 1-5 As shown, the system includes a biological treatment tank 1, a transfer pump 2, and an activated sludge filter assembly. The biological treatment tank 1 includes a tank body and a sludge return inlet located on the tank body. The sludge return inlet is connected to the tank body and can receive returned sludge. The activated sludge filter assembly is equipped with an inlet, a filtrate outlet, and a sludge retention outlet. The inlet of the activated sludge filter assembly is connected to the biological treatment tank 1. The sludge return inlet of the biological treatment tank 1 is connected to the sludge retention outlet via a pipe. The filtrate outlet of the activated sludge filter assembly is connected to the secondary sedimentation tank 4 or the treated wastewater discharge network via a pipe. Preferably, a transfer pump 2 is installed between the activated sludge filter assembly and the biological treatment tank 1. The inlet of the transfer pump 2 is connected to the tank body of the biological treatment tank 1 via a pipe. The function of the transfer pump 2 is to pressurize and transport the activated sludge in the biological treatment tank 1 to the activated sludge filter assembly. The inlet of the activated sludge filter assembly is connected to the outlet of the transfer pump 2 via a pipe.

[0024] Work methods: S1. Activated sludge extraction and transportation: Start the transfer pump 2. The transfer pump 2 extracts activated sludge from the body of the biological tank 1 through the pipe connected to the inlet end, and through the pressurization, transports the activated sludge to the inlet of the activated sludge filter component through the pipe connected to the outlet end.

[0025] S2, Activated sludge solid-liquid separation: After receiving the delivered activated sludge, the activated sludge filter module filters and separates it, so that the liquid (filtrate) in the activated sludge is discharged through the filtrate outlet, while the solid (retained sludge) is retained inside the module.

[0026] S3. Sludge interception and return: The intercepted activated sludge is transported through the intercepted sludge discharge port of the activated sludge filter assembly to the sludge return inlet of biological tank 1 via a connecting pipe, and finally returned to biological tank 1 to participate in the biochemical reaction again. The return ratio of the intercepted sludge can be adjusted by the valve on the return pipe.

[0027] S4. Filtrate diversion treatment: Depending on the actual treatment requirements, the filtrate outlet can be selectively connected to the secondary sedimentation tank 4 or the qualified water discharge network. In this way, the filtrate can be selectively transported to the secondary sedimentation tank 4 to reduce the solid load of the secondary sedimentation tank 4, or directly transported to the qualified water discharge network to replace the secondary sedimentation tank 4.

[0028] In one embodiment, the activated sludge filter assembly can be installed between the biological treatment tank 1 and the secondary sedimentation tank 4 via a mounting bracket. This arrangement facilitates shortening the pipeline path of activated sludge from the biological treatment tank 1 to the filter assembly and then to the secondary sedimentation tank 4, reducing head loss during transportation. In this case, the outlet of the transfer pump 2 is connected to the inlet of the activated sludge filter assembly via a pipeline.

[0029] In one embodiment, the activated sludge filter assembly can be embedded in the end chamber of the biological treatment tank 1 via a mounting bracket. The inlet of the activated sludge filter assembly is directly connected to the end chamber of the biological treatment tank 1, eliminating the need for additional pipeline transportation, allowing the activated sludge to autonomously enter the filter assembly. Its sludge discharge outlet is connected to the influent mixing zone at the front end of the biological treatment tank 1 via a pipeline, ensuring that the retained activated sludge can be quickly returned to the biological reaction system. This built-in layout does not occupy the ground space of the wastewater treatment plant, making it particularly suitable for small and medium-sized projects with limited site area, while also shortening the transport path of the activated sludge.

[0030] In this embodiment, the activated sludge filtration device can completely replace the secondary sedimentation tank 4 by adjusting the filtration precision to achieve the designed effluent requirements. The activated sludge filtration device is a physical filtration system that achieves solid-liquid separation based on porous media interception. The filtration precision of the activated sludge filtration device can be adjusted within the range of 10~700μm, and the processing capacity and footprint can be balanced by adjusting the filtration precision according to actual conditions. When the filtration precision is adjusted to meet the designed effluent requirements, it can completely replace the secondary sedimentation tank 4 to achieve direct discharge after sludge-water separation. In addition, the activated sludge filtration device can also achieve sludge dialysis in the biological treatment tank 1 by adjusting the filtration precision. When the filtration precision is adjusted to be able to intercept "large-diameter inorganic matter in activated sludge," such as sand and gravel and undegraded particles, the small-diameter activated sludge rich in microorganisms can be returned to the biological treatment tank 1 to achieve sludge dialysis and optimize the efficiency of the biochemical reaction.

[0031] In this embodiment, the activated sludge filter assembly can treat a portion of the effluent from the end of biological treatment tank 1, for example, 30% to 70% of the total effluent from biological treatment tank 1, based on the design treatment capacity of the wastewater treatment plant. This portion of the effluent is introduced into the activated sludge filter assembly through a pipeline. After the activated sludge is intercepted by the filter assembly, the filtrate produced by the filtration merges with the unfiltered remaining effluent from biological treatment tank 1 and flows together into the secondary sedimentation tank 4 through a pipeline. Because the activated sludge filter assembly pre-intercepts a portion of the activated sludge, the total solid load entering the secondary sedimentation tank 4 is reduced, thereby increasing its actual treatment capacity while ensuring that the surface load of the secondary sedimentation tank 4 does not exceed the standard. At the same time, the activated sludge intercepted by the filter assembly can be returned to biological treatment tank 1 in two ways: one is to pump it to the inlet area at the front end of biological treatment tank 1 through a return pump via a pipeline, and the other is to discharge it directly into the mixed liquor return channel of biological treatment tank 1. Both methods can reduce the sludge return flow rate of the secondary sedimentation tank 4 and reduce the sludge transport pressure of the secondary sedimentation tank 4.

[0032] In one embodiment, the activated sludge filtration device includes two types: a rotary disc filter 31 and a mesh belt filter 32. The rotary disc filter 31 includes a support frame, a porous disc rotatably mounted on the support frame, and a matching backwashing assembly. During operation, the porous disc is partially immersed in the activated sludge, achieving continuous filtration through rotation. The backwashing assembly periodically washes the sludge trapped on the disc surface to maintain filtration efficiency. The other type is the mesh belt filter 32, which includes a frame, a filter mesh belt tensioned on the frame, and a motor driving the mesh belt's circulation. When the activated sludge flows through the mesh belt, the liquid passes through the mesh belt pores to form filtrate, and the trapped sludge is carried by the mesh belt to the end for discharge. The rotary disc filter 31 is suitable for scenarios requiring high filtration precision, while the mesh belt filter 32 is more suitable for treating activated sludge containing a large number of large-diameter particles.

[0033] In one embodiment, as an example, please refer to Figure 1As shown, a rotary disc filter 31 is installed between the biological treatment tank 1 and the secondary sedimentation tank 4. The inlet of the rotary disc filter 31 is connected to the end of the biological treatment tank 1. Preferably, a transfer pump 2 is installed between the biological treatment tank 1 and the rotary disc filter 31. The inlet of the transfer pump 2 is connected to the end of the biological treatment tank 1, and the outlet of the transfer pump 2 is connected to the inlet of the rotary disc filter 31. The sludge discharge outlet of the rotary disc filter 31 is connected to the inlet mixing zone at the front end of the biological treatment tank 1 via a return pipe; the filtrate outlet of the rotary disc filter 31 is directly connected to the inlet of the secondary sedimentation tank 4 via a pipe. Meanwhile, a separate outlet pipe is also installed at the end of the biological treatment tank 1. One end of this pipe is connected to the tank cavity at the end of the biological treatment tank 1, and the other end is directly connected to the inlet pipe of the secondary sedimentation tank 4, forming a "diverted inlet" structure. That is, the effluent from the biological treatment tank 1 can be divided into two parts. One part enters the secondary sedimentation tank 4 after being filtered by the rotary disc filter device 31, and the other part flows into the secondary sedimentation tank 4 through this direct pipe. The diversion ratio can be synchronously controlled by the flow regulating valve of the transfer pump 2. The filtrate intercepted by the rotary disc filter device 31 is discharged through the filtrate outlet and merges with the unfiltered remaining effluent from the biological treatment tank 1 before flowing into the secondary sedimentation tank 4 through the pipe.

[0034] During operation, after the transfer pump 2 starts, it sends a portion of the activated sludge wastewater from the end of the biological treatment tank 1 into the rotary disc filter 31. The core of this rotary disc filter 31 is a porous disc. During operation, the drive motor drives the porous disc to rotate slowly at a preset speed, with the lower part of the disc immersed in the activated sludge to be filtered. Under the combined pressure of the transfer pump 2 and its own gravity, the wastewater permeates through the porous structure of the disc. Activated sludge particles larger than the pore size are retained on the disc surface, while the filtrate with the required suspended solids concentration passes through the disc into the internal effluent pipe and is finally discharged into the secondary sedimentation tank 4 through the filtrate outlet. When the disc rotates to the area above the water surface, the backwashing component of the rotary disc filter 31 is activated, using high-pressure clean water to rinse the disc surface, thoroughly removing the retained activated sludge. The stripped activated sludge falls directly into the rotary disc filter tank, where it mixes thoroughly with the incoming activated sludge (i.e., the influent). As the equipment continues to operate, the sludge concentration in the rotary disc tank gradually increases, eventually stabilizing at a fixed value suitable for the current treatment conditions. This stable value is the return sludge concentration, ensuring the efficiency of subsequent biological reactions. The mixed return sludge overflows from the overflow port at the top of the rotary disc tank, flows through the pipe connected to the overflow port into the return pipe, and is ultimately transported to the influent mixing zone at the front end of biological treatment tank 1 to participate in the biological reaction again.

[0035] By pre-retaining some of the activated sludge in the effluent of the biological treatment tank 1 through the rotary filter device 31, the total solid load entering the secondary sedimentation tank 4 can be reduced, thereby increasing the actual treatment capacity of the secondary sedimentation tank 4. At the same time, the sludge return design can reduce the loss of activated sludge in the biological treatment tank 1 and ensure the stability of the amount of microorganisms in the biochemical reaction.

[0036] In one embodiment, as Example 2, please refer to Figure 2 As shown, a mesh belt filter 32 can be used instead of the aforementioned rotary disc filter 31. The mesh belt filter 32 is also mounted between the biological treatment tank 1 and the secondary sedimentation tank 4 via a mounting bracket. The installation position of the mesh belt filter 32 can be consistent with that of the rotary disc filter 31, eliminating the need for additional adjustments to the existing pipeline layout and reducing modification costs. The inlet of the mesh belt filter 32 is connected to the end of the biological treatment tank 1, the filtrate outlet of the mesh belt filter 32 is connected to the secondary sedimentation tank 4, and the sludge discharge outlet of the mesh belt filter 32 is connected to the front end of the biological treatment tank 1. Simultaneously, the outlet at the end of the biological treatment tank 1 is also directly connected to the secondary sedimentation tank 4 via a pipeline. The core structure of the mesh belt filter 32 includes a frame and a filter belt tensioned on the frame for sludge dialysis of the effluent from the biological treatment tank 1. A transfer pump 2 is also installed between the inlet of the mesh belt filter 32 and the biological treatment tank 1. During operation, the transfer pump 2 delivers a portion of the effluent from the biological treatment tank 1 to the belt filter device 32. As the water flows through the filter belt, large-diameter impurities are trapped, while small-diameter activated sludge rich in active microorganisms passes through the belt with the filtrate and is discharged through the filtrate outlet. This filtrate, along with the unfiltered remaining effluent from the biological treatment tank 1, flows into the secondary sedimentation tank 4 through a pipeline. The trapped large-diameter impurities flow out through the sludge discharge outlet and can still be transported back to the influent mixing zone at the front end of the biological treatment tank 1 through the return pipeline. This design optimizes the activity of the sludge entering the secondary sedimentation tank 4 through sludge dialysis, further reducing the solids load of the secondary sedimentation tank 4 and improving the overall treatment efficiency.

[0037] In one embodiment, as Example 3, please refer to Figure 3 As shown, the rotary filter 31 can also be placed at the end of the biological treatment tank 1, that is, the rotary filter 31 is set in the tank cavity at the end of the biological treatment tank 1. Preferably, the rotary filter 31 is embedded in the side wall or bottom of the tank cavity at the end of the biological treatment tank 1 through a fixing seat. This built-in layout does not occupy the ground space outside the biological treatment tank 1, and is especially suitable for small and medium-sized sewage treatment plants with limited site area. At the same time, the activated sludge in the biological treatment tank 1 can directly enter the inlet of the rotary filter 31. The filtrate outlet of the rotary filter 31 is connected to the secondary sedimentation tank 4 through a pipe; the sludge discharge outlet of the rotary filter 31 is directly connected to the inlet mixing zone at the front end of the biological treatment tank 1 through a pipe, so that the intercepted activated sludge can be quickly returned to the starting end of the biological reaction.

[0038] In one embodiment, as Example 4, please refer to Figure 4 As shown, the effluent outlet of the biological treatment tank 1 is directly connected to the inlet of the rotary disc filter 31 via a pipe, allowing all the effluent from the biological treatment tank 1 to enter the rotary disc filter 31 for treatment. This rotary disc filter 31 can be fitted with a high-precision porous disc to meet high-precision filtration requirements. After physical filtration, the suspended solids concentration of the filtrate can be stably controlled within a preset range, meeting the wastewater treatment plant's design effluent standards. It can meet discharge requirements without needing to enter the secondary sedimentation tank 4, thus completely replacing the secondary sedimentation tank 4. Simultaneously, the activated sludge retained by the rotary disc filter 31 is diverted through branch pipes. One branch pipe connects to the inlet mixing zone at the front of the biological treatment tank 1, and is equipped with a flow regulating valve to adjust the return ratio according to the sludge concentration in the biological treatment tank 1, allowing the activated sludge to return to the biological treatment tank 1 to participate in the reaction again. The other branch pipe connects to the sludge treatment device of the wastewater treatment plant, and is equipped with a sludge discharge valve. The remaining retained sludge is discharged as surplus sludge to maintain the dynamic balance of sludge in the biological treatment tank 1. The filtrate outlet of the rotary filter device 31 is connected to the qualified water discharge pipeline network. When the rotary filter device 31 completely replaces the secondary sedimentation tank 4, the filtered water (i.e. filtrate) will be discharged directly into the qualified water discharge pipeline network of the sewage treatment plant through the filtrate outlet of the device.

[0039] In one embodiment, as Example 5, please refer to Figure 5 As shown, the inlet of the mesh belt filter 32 is connected to the activated sludge outlet at the end of the biological treatment tank 1 via the transfer pump 2. Simultaneously, an additional effluent pipe is provided at the end of the biological treatment tank 1, which is directly connected to the secondary sedimentation tank 4. During operation, the effluent from the biological treatment tank 1 is divided according to a preset ratio. A portion of the effluent flows through the mesh belt filter 32, while the remaining effluent flows directly into the secondary sedimentation tank 4. The division ratio can be flexibly controlled by the flow regulating valve of the transfer pump 2. The sludge discharge outlet of the mesh belt filter 32 is connected to the sludge treatment device of the wastewater treatment plant via a sludge discharge pipe, while the filtrate outlet is connected to the influent mixing zone at the front end of the biological treatment tank 1 via a return pipe. The specific working process is as follows: Pump 2 sends a portion of the activated sludge wastewater from biological treatment tank 1 into a belt filter device 32, where large-particle inorganic matter in the wastewater is intercepted through physical filtration. The filtered filtrate is returned to biological treatment tank 1 via a return pipe to participate in the biochemical reaction again. The intercepted large-particle inorganic matter is then conveyed to the end of the device by the belt, scraped off by a scraper, and finally transported to the sludge treatment process. By selectively intercepting large-particle inorganic matter from the activated sludge in biological treatment tank 1, the MLVSS / MLSS ratio of the activated sludge in biological treatment tank 1 can be increased, significantly improving the microbial activity and pollutant degradation efficiency of the activated sludge. At the same time, since some of the inorganic matter in the wastewater has been pre-intercepted, the total solids load entering the secondary sedimentation tank 4 is reduced, effectively avoiding sludge loss caused by excessive solids load in the secondary sedimentation tank 4, and ensuring the sludge-water separation effect.

[0040] In one embodiment, as Example 6, the rotary disc filter 31 and the mesh belt filter 32 can be used in conjunction. The inlet of the rotary disc filter 31 is connected to the activated sludge outlet at the end of the biological treatment tank 1 via a pipe; the filtrate outlet of the rotary disc filter 31 is connected to the secondary sedimentation tank 4 via a pipe; the sludge discharge outlet of the rotary disc filter 31 is connected to the inlet of the mesh belt filter 32 via a pipe; the filtrate outlet of the mesh belt filter 32 is connected to the inlet mixing zone at the front end of the biological treatment tank 1 via a return pipe; and the sludge discharge outlet of the mesh belt filter 32 is connected to the sludge treatment device of the wastewater treatment plant via a sludge discharge pipe. The workflow is as follows: A portion of the activated sludge effluent from biological treatment tank 1 first enters a rotary disc filter 31, where activated sludge is physically filtered and retained. The filtrate meeting the requirements flows directly into the secondary settling tank 4, reducing the solids load in the secondary settling tank 4. The sludge retained by the rotary disc filter 31 is then transported to a belt filter 32. After belt filtration, the filtrate returns to biological treatment tank 1 to participate in the reaction again, while the retained large-particle impurities directly enter the sludge treatment device. This combined design can both reduce the load on the secondary settling tank 4 through the rotary disc filter 31 and recover activated sludge and separate inorganic matter through the belt filter 32, thereby increasing the MLVSS / MLSS ratio of the activated sludge in biological treatment tank 1 and reducing the impurity content entering the sludge treatment device, thus lowering subsequent treatment costs.

[0041] It should be noted that, for those skilled in the art, it is obvious that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0042] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. An adapter device for an activated sludge filtration type secondary sedimentation tank, characterized in that, include: Biological tank (1), the biological tank (1) includes a tank body and a sludge return inlet for receiving returned sludge, the sludge return inlet being connected to the tank body; An activated sludge filter assembly is provided with an inlet, a filtrate outlet and a sludge interception outlet. The inlet is connected to the biological tank (1) through a pipe, and the sludge return inlet of the biological tank (1) is connected to the sludge interception outlet through a pipe. The filtrate outlet of the activated sludge filtration component is connected to the secondary sedimentation tank (4) or the qualified water discharge network via a pipeline.

2. The activated sludge filtration type secondary sedimentation tank adapter device according to claim 1, characterized in that, It also includes a transfer pump (2), the inlet of which is connected to the body of the biochemical tank (1) through a pipe, and the outlet of which is connected to the inlet of the activated sludge filter assembly through a pipe.

3. The activated sludge filtration type secondary sedimentation tank adapter device according to claim 2, characterized in that, The activated sludge filtration assembly is located between the biological treatment tank (1) and the secondary sedimentation tank (4).

4. The activated sludge filtration type secondary sedimentation tank adapter device according to claim 1, characterized in that, The activated sludge filter assembly is embedded in the end chamber of the biological treatment tank (1); the inlet of the activated sludge filter assembly is connected to the end chamber of the biological treatment tank (1); the sludge discharge outlet of the activated sludge filter assembly is connected to the front end of the biological treatment tank (1) through a pipe.

5. The activated sludge filtration type secondary sedimentation tank adapter device according to claim 1, characterized in that, The activated sludge filtration assembly includes a rotary disc filter (31) and a mesh belt filter (32); the rotary disc filter (31) includes a support, a porous disc rotatably mounted on the support, and a matching backwashing assembly; the mesh belt filter (32) includes a frame and a filter mesh belt tensioned on the frame.

6. The activated sludge filtration type secondary sedimentation tank adapter device according to claim 5, characterized in that, The rotary filter device (31) is located between the biological tank (1) and the secondary sedimentation tank (4); the inlet of the rotary filter device (31) is connected to the end of the biological tank (1); the filtrate outlet of the rotary filter device (31) is connected to the secondary sedimentation tank (4); and the sludge discharge outlet of the rotary filter device (31) is connected to the front end of the biological tank (1).

7. The activated sludge filtration type secondary sedimentation tank adapter device according to claim 5, characterized in that, The mesh belt filter device (32) is located between the biological tank (1) and the secondary sedimentation tank (4); the inlet of the mesh belt filter device (32) is connected to the end of the biological tank (1); the filtrate outlet of the mesh belt filter device (32) is connected to the secondary sedimentation tank (4); and the sludge discharge outlet of the mesh belt filter device (32) is connected to the front end of the biological tank (1).

8. The activated sludge filtration type secondary sedimentation tank adapter device according to claim 5, characterized in that, The rotary filter device (31) is installed in the end chamber of the biological tank (1); the inlet of the rotary filter device (31) is connected to the end chamber of the biological tank (1); the filtrate outlet of the rotary filter device (31) is connected to the secondary sedimentation tank (4) through a pipe; and the sludge discharge outlet of the rotary filter device (31) is connected to the front end of the biological tank (1) through a pipe.

9. The activated sludge filtration type secondary sedimentation tank adapter device according to claim 5, characterized in that, The outlet of the biochemical tank (1) is connected only to the rotary filter (31); the rotary filter (31) is provided with a sludge interception outlet; the sludge interception outlet is connected to two branches, the first branch is connected to the inlet mixing zone at the front end of the biochemical tank (1), the second branch is connected to the sewage treatment device, and the filtrate outlet of the rotary filter (31) is connected to the qualified water discharge pipeline.

10. The activated sludge filtration type secondary sedimentation tank adapter device according to claim 5, characterized in that, The inlet of the mesh belt filter device (32) is connected to the biological tank (1); the end of the biological tank (1) is also provided with an outlet pipe connected to the secondary sedimentation tank (4); the sludge discharge outlet of the mesh belt filter device (32) is connected to the sludge treatment device through the sludge discharge pipe, and the filtrate outlet of the mesh belt filter device (32) is connected to the front end of the biological tank (1) through the return pipe.

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