Industrial wastewater treatment system with closed sludge return structure

Abstract

This invention relates to the field of wastewater treatment technology and discloses a closed-loop sludge recirculation structure industrial wastewater treatment system. The system includes a base plate, with a secondary sedimentation tank and a reaction tank installed on the left and right sides of the upper end of the base plate, respectively. The reaction tank consists of an anaerobic tank, an anoxic tank, and an aerobic tank. An internal recirculation pipe is connected to the outer wall of the rear end of the anoxic and aerobic tanks. An internal recirculation pump is installed on the outer wall of the rear end of the reaction tank to connect with the internal recirculation pipe and transport the nitrified liquid from the end of the aerobic tank to the inlet of the anoxic tank. This closed-loop sludge recirculation structure industrial wastewater treatment system effectively solves the problems of existing sludge recirculation systems, which often use a single-pipe design. When the pipe needs maintenance due to sludge deposition and wear, it not only interrupts wastewater treatment operations but also disrupts the stable growth environment of the microbial community in the biological system. Furthermore, pipe unclogging relies on manual disassembly and cleaning or forward flushing with clean water, which can cause sludge overflow and secondary pollution, resulting in poor unclogging performance.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, and more specifically to an industrial wastewater treatment system with a closed sludge recirculation structure. Background Technology

[0002] Sludge recirculation, a core component of the activated sludge process, serves to return the activated sludge settled in the secondary sedimentation tank to the biological reactor to maintain a sufficient concentration of microorganisms. The stability of the recirculation, the uniformity of sludge concentration, and the energy consumption directly determine the microbial community structure, pollutant degradation efficiency, system resistance to shock loads, and overall treatment costs within the biological reactor. Traditional sludge recirculation systems for industrial wastewater treatment require a sludge recirculation pump to transport the activated sludge settled at the bottom of the secondary sedimentation tank to the front end of the biological reactor. Because the sludge often contains fibers, suspended solids, and hard particles, these particles accumulate on the inner walls of the pipeline in the transport area and at bends, leading to large fluctuations in the recirculation flow rate and, in severe cases, complete pipeline blockage.

[0003] In response to this, this application designs an industrial wastewater treatment system with a closed-loop sludge return structure. Existing sludge return systems mostly adopt a single-pipe design. First, when the pipeline needs maintenance due to sludge deposition and wear, the entire line must be shut down, which not only interrupts wastewater treatment operations and causes risks of effluent exceeding standards and environmental violations, but also disrupts the stable growth environment of the microbial community in the biological system. Second, pipeline unblocking relies on manual disassembly and cleaning or forward flushing with clean water, which is labor-intensive, has high operation and maintenance costs, and can also cause secondary pollution from sludge overflow. Moreover, the unblocking effect is poor, and there are common problems such as backflow of media when the pump is stopped and residual sludge deposition and blockage on the inner wall of the pipeline, which seriously affect the long-term stable operation of the system. Summary of the Invention

[0004] To address the aforementioned shortcomings of existing technologies, this invention provides an industrial wastewater treatment system with a closed-loop sludge recirculation structure. This system effectively solves the problems of existing sludge recirculation systems, which often employ a single-pipe design. When the pipes require maintenance due to sludge deposition and wear, not only is the wastewater treatment operation interrupted, but the stable growth environment of the microbial community in the biochemical system is also disrupted. Furthermore, pipe unblocking relies on manual disassembly and cleaning or forward flushing with clean water, which can cause sludge overflow and secondary pollution, resulting in poor unblocking effects.

[0005] To achieve the above objectives, the present invention provides the following technical solution: This invention provides an industrial wastewater treatment system with a closed-loop sludge recirculation structure, comprising: The bottom plate has a secondary sedimentation tank and a reaction tank installed on the left and right sides of its upper end, respectively. The reaction tank consists of an anaerobic tank, an anoxic tank, and an aerobic tank. The anoxic tank and the aerobic tank are connected by an internal return pipe on their rear outer walls. An internal return pump is installed on the rear outer wall of the reaction tank to connect with the internal return pipe and transport the nitrified liquid at the end of the aerobic tank to the inlet of the anoxic tank. External return pipes are installed through the reaction tank and the secondary sedimentation tank on their lower sides. The external return pipes are L-shaped with a solid tail. A sludge return pump is installed on the upper end of the bottom plate below the reaction tank to connect with the left external return pipe and transport the bottom sludge to the anaerobic tank. The two external return pipes are connected by a pipe switching section, which is equipped with a backflushing and unblocking section. The pipeline switching section includes a partition bracket that is slidably mounted on the external return pipe. The partition bracket consists of two support plates and a sleeve. Pipeline support seats are slidably mounted on the outer walls of the left and right sleeves respectively. High-level pipes are symmetrically and detachably installed on the left and right pipeline support seats. The high-level pipes consist of an inclined section and a vertical section. Locking groups are provided on the pipeline support seats and the partition bracket.

[0006] Furthermore, the backflushing and unblocking section includes limiting sliding holes on the outer walls of both the inclined section and the vertical section of the high-level pipe. The limiting sliding holes are designed in an oblong shape, and an mounting slide is slidably installed on the inner wall of the limiting sliding hole. The mounting slide consists of an oblong slider and a fan-shaped magnetic block. An inner sliding plate is installed at the end of the oblong slider away from the fan-shaped magnetic block and is slidably connected to the inner wall of the high-level pipe. The inner sliding plate is a hollow tubular structure. Electromagnets are installed on the upper end of the pipeline support corresponding to both the front and rear high-level pipes. An electromagnetic collar is fixedly sleeved on the outer wall of the inclined section of the high-level pipe above the limiting sliding hole. A backflushing collection group is jointly provided on the pipeline support and the high-level pipe.

[0007] Furthermore, the outer wall of the external return pipe is provided with round holes corresponding to the two high-level pipes before and after, and the outer wall of the upper end of the pipe support is also provided with round holes corresponding to the two high-level pipes before and after. The outer wall of the middle part of the sleeve of the partition bracket is provided with a docking hole corresponding to the round hole. The first and last ends of the high-level pipe are respectively connected to the round holes of the corresponding pipe support.

[0008] Furthermore, the locking assembly includes a locking plate that is integrally installed at both ends of the pipeline support. Several locking plates are installed, and the plates are evenly distributed in a circle. Each locking plate has an arc-shaped plate structure with a hole in the middle. Air storage slots are provided on both the front and rear support plates of the partition bracket. The air storage slots are designed in a ring shape, and an air hole is provided at the upper end of the support plate that connects to the corresponding air storage slot.

[0009] Furthermore, the locking assembly also includes receiving slots located on the inner circular wall of the support plate corresponding to the insertion holes. Several receiving slots are provided, and the receiving slots are evenly distributed around the circumference. The receiving slots are connected to the gas storage tank. The receiving slots and the inner wall of the gas storage tank are slidably installed with locking blocks by tension springs, and the receiving slots and locking blocks are staggered.

[0010] Furthermore, the backflushing collection group includes a transfer hole located on the left pipeline support base corresponding to both the front and rear high-level pipes. The outer wall of the inclined section of the high-level pipe is provided with a sludge discharge hole connected to the corresponding transfer hole. A collection box with a vent hole is installed on the right end of the left pipeline support base, and both the front and rear transfer holes are connected to the collection box.

[0011] Furthermore, the backflushing collection group also includes a venting chamber located on the right-side pipeline support base corresponding to the front and rear high-level pipes. The venting chamber consists of two oblique holes and a connecting groove. The outer wall of the vertical section of the high-level pipe has a second air hole connected to the corresponding oblique hole. An air pump is installed on the left end of the right-side pipeline support base via a mounting base. The air outlet of the air pump is connected to the venting chamber via an air pipe.

[0012] Furthermore, hydraulic push rods for driving the corresponding baffle supports to move back and forth are installed through the lower side of both the reaction tank and the secondary sedimentation tank. Support slide rods are installed on the lower side of the front and rear support plates on the baffle supports. The support slide rods slide through the corresponding pipe support seats, and buffer springs are sleeved on the outer wall of the support slide rods between the pipe support seats and the front and rear support plates.

[0013] Furthermore, an extension cover is installed at the front end of the support plate of the partition bracket located on the front side. An avoidance groove is opened on the outer side of the outer wall of the extension cover corresponding to the backflushing and unblocking part. A piston rod is installed on the inner wall of the front end of the extension cover. The piston rod is slidably installed on the corresponding external return pipe, and the piston outer wall on the piston rod is damped and slidably attached to the inner wall of the external return pipe. A check valve is also installed at the end of the external return pipe on the right side located in the reaction tank.

[0014] Furthermore, there are symmetrical connecting pipes on the upper left side of the reaction tank, with the end of the connecting pipe away from the reaction tank connected to the secondary sedimentation tank. A base is also installed on the lower front side of the anaerobic tank. The lower end of the left pipe support is fixedly connected to the base plate, and the lower end of the right pipe support is fixedly connected to the base.

[0015] The technical solution provided by this invention has the following advantages compared with the prior art: This invention provides an industrial wastewater treatment system with a closed-loop sludge recirculation structure. During the online switching of pipelines and continuous operation of the system, when the current working high-level pipe reaches its operating cycle or requires maintenance due to abnormal flow, the sludge recirculation pump is first paused. Pressure is released through a pair of air storage tanks via air vents, causing the locking block to retract and release the baffle support. Then, a hydraulic push rod drives the baffle support to the switching position, allowing the rear standby high-level pipe and the external recirculation pipe to form a new closed recirculation channel. Subsequently, electricity is applied to drive the inner sliding plate to seal the pipe openings, and air is injected into the air storage tanks to complete the locking process. The recirculation pump is then restarted. The sludge pump operates in a cycle, repeating the above steps to rotate the pipeline. In case of a sudden failure, it directly switches to isolate the fault and puts the backup pipeline into use. This stage adopts a purely mechanical hole-position docking switch, avoiding the defects of traditional valve switching such as easy jamming and sealing failure. Only a short pause of the return pump is needed to complete the seamless switch, solving the core pain point that a single pipeline maintenance requires a complete shutdown and cannot operate continuously. With the locking structure and follow-up sealing to avoid pipeline misalignment and sludge accumulation, the triple anti-backflow structure can block the backflow of the medium in time, ensuring the continuous and stable operation of the system and avoiding environmental risks.

[0016] During the offline pipeline backflushing and sludge centralized recovery stage, for the front high-level pipe switched to maintenance status, the polarity of the electromagnetic collar is first switched. The inner sliding plate is moved by magnetic repulsion and attraction, connecting the sludge discharge hole with the transfer hole, and the second air hole with the ventilation chamber to form a closed backflushing channel. Then, the air pump is started to send in high-pressure airflow to flush the sludge and caking material on the inner wall of the pipeline in reverse. The airflow carrying the sludge enters the collection box for centralized collection through the corresponding channels. After the backflushing is completed, the magnetic pole is switched to drive the inner sliding plate to reset and seal, so that the high-level pipe returns to standby status. This stage uses reverse high-pressure airflow backflushing, which can achieve dredging without dead angles without disassembling the pipeline. It solves the pain points of high cost, easy secondary pollution, and poor water flushing effect of traditional manual cleaning. The fully closed recovery can avoid sludge overflow, and the sludge can be recycled for reuse, reducing operation and maintenance costs. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0018] Figure 1 This is a first-view three-dimensional structural diagram in an embodiment of the present invention; Figure 2 This is a schematic diagram of the second-view three-dimensional structure in an embodiment of the present invention; Figure 3 This is a three-dimensional structural diagram of the reaction tank, internal reflux pump, and internal reflux pipe in an embodiment of the present invention; Figure 4This is a schematic diagram of the three-dimensional separation of the external return pipe and the pipeline switching section in an embodiment of the present invention; Figure 5 This is a schematic diagram of a partial three-dimensional cross-section of the external return pipe, the left-side pipe support, and the partition bracket in an embodiment of the present invention. Figure 6 This is a schematic diagram of a partial three-dimensional cross-section of the left-side pipeline support and partition bracket in an embodiment of the present invention; Figure 7 This is a schematic diagram of a partial three-dimensional cross-section of the left-side pipeline support in an embodiment of the present invention; Figure 8 This is a first structural schematic diagram of a partial three-dimensional cross-section of the right-side pipeline support in an embodiment of the present invention; Figure 9 This is a schematic diagram of the second structure of a partial three-dimensional cross-section of the right-side pipeline support in an embodiment of the present invention; Figure 10 This is a schematic diagram of the three-dimensional separation of the high-position pipe and the backflushing and unblocking section in an embodiment of the present invention; Figure 11 This is a three-dimensional structural diagram of the external return pipe and the base in an embodiment of the present invention.

[0019] The labels in the diagram represent: 1. Reaction tank; 2. Secondary sedimentation tank; 21. Connecting pipe; 22. Base; 3. Internal return pump; 4. Internal return pipe; 5. Return sludge pump; 6. External return pipe; 61. Check valve; 7. Pipeline switching section; 71. Pipeline support seat; 72. High-level pipe; 73. Baffle bracket; 731. Hydraulic push rod; 732. Support slide rod; 733. Extension cover plate; 734. Piston rod; 74. Lock Fixed assembly; 741, clamping plate; 742, air storage tank; 743, air hole one; 744, receiving tank; 745, clamping block; 8, backflushing and unblocking section; 81, limiting sliding hole; 82, mounting slide; 83, inner sliding plate; 84, electromagnet; 85, electromagnetic collar; 86, backflushing collection assembly; 861, transfer hole; 862, sludge discharge hole; 863, collection box; 864, venting chamber; 865, air hole two; 866, air pump. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0021] The present invention will be further described below with reference to embodiments.

[0022] Example: Please see Figures 1-11 This invention provides a technical solution: an industrial wastewater treatment system with a closed sludge recirculation structure, comprising: The bottom plate has a secondary sedimentation tank 2 and a reaction tank 1 installed on the left and right sides of the upper end. The reaction tank 1 consists of an anaerobic tank, an anoxic tank and an aerobic tank. The anoxic tank and the aerobic tank are connected by an internal return pipe 4 on the outer wall of the rear end. An internal return pump 3 is installed on the outer wall of the rear end of the reaction tank 1 to connect with the internal return pipe 4 and transport the nitrified liquid at the end of the aerobic tank to the inlet of the anoxic tank. External return pipes 6 are installed through the lower side of the reaction tank 1 and the secondary sedimentation tank 2. The external return pipe 6 is an L-shaped design with a solid tail. A return sludge pump 5 is installed at the upper end of the bottom plate below the reaction tank 1 to connect with the left external return pipe 6 and transport the bottom sludge to the anaerobic tank. The two external return pipes 6 are connected by a pipeline switching section 7 and a backflushing and unblocking section 8. The pipeline switching section 7 includes a partition bracket 73 that is slidably mounted on the external return pipe 6. The partition bracket 73 consists of two support plates and a sleeve. Pipeline support seats 71 are slidably mounted on the outer walls of the left and right sleeves respectively. A high-level pipe 72 is detachably mounted symmetrically on both the left and right pipeline support seats 71. The high-level pipe 72 consists of an inclined section and a vertical section. A locking group 74 is provided on both the pipeline support seats 71 and the partition bracket 73.

[0023] The backflushing and unblocking section 8 includes limiting sliding holes 81 located on the outer walls of the inclined section and the vertical section of the high-level pipe 72. The limiting sliding holes 81 are waist-shaped. An installation slide 82 is slidably installed on the inner wall of the limiting sliding holes 81. The installation slide 82 consists of a waist-shaped slider and a fan-shaped magnetic block. An inner sliding plate 83 is slidably connected to the inner wall of the high-level pipe 72 at the end of the waist-shaped slider away from the fan-shaped magnetic block. The inner sliding plate 83 is a hollow tubular structure. Electromagnets 84 are installed on the upper end of the pipe support 71 corresponding to the two high-level pipes 72. An electromagnetic collar 85 is fixedly sleeved on the outer wall of the inclined section of the high-level pipe 72 above the limiting sliding holes 81. A backflushing collection group 86 is jointly provided on the pipe support 71 and the high-level pipe 72.

[0024] The outer wall of the external return pipe 6 is provided with round holes corresponding to the two front and rear high-level pipes 72. The outer wall of the upper end of the pipe support 71 is also provided with round holes corresponding to the two front and rear high-level pipes 72. The outer wall of the middle part of the sleeve of the partition bracket 73 is provided with a docking hole corresponding to the round hole. The first end and the last end of the high-level pipe 72 are respectively connected to the round holes of the corresponding pipe support 71.

[0025] The locking assembly 74 includes a locking plate 741 that is integrally installed at both ends of the pipeline support 71. Several locking plates 741 are installed and are evenly distributed around the circumference. Each locking plate 741 has an arc-shaped plate structure with a hole in the middle. The partition bracket 73 has an air storage groove 742 on both the front and rear support plates. The air storage groove 742 is a ring design. The upper end of the support plate has an air hole 743 that connects to the corresponding air storage groove 742.

[0026] The locking assembly 74 also includes a receiving groove 744 located on the inner wall of the circular support plate corresponding to the insertion hole. Several receiving grooves 744 are provided and are evenly distributed around the circumference. The receiving grooves 744 are connected to the gas storage tank 742. The receiving grooves 744 and the inner wall of the gas storage tank 742 are slidably mounted with a locking block 745 through a tension spring. The several receiving grooves 744 and the several locking plates 741 are staggered.

[0027] The backwash collection group 86 includes a transfer hole 861 located on the left pipeline support 71 corresponding to both the front and rear high-level pipes 72. The outer wall of the inclined section of the high-level pipe 72 is provided with a mud discharge hole 862 connected to the corresponding transfer hole 861. A collection box 863 with a vent hole is installed at the right end of the left pipeline support 71. Both the front and rear transfer holes 861 are connected to the collection box 863.

[0028] The backflush collection group 86 also includes a venting chamber 864 located on the right-side pipeline support 71 corresponding to the two front and rear high-level pipes 72. The venting chamber 864 consists of two front and rear oblique holes and a connecting groove. The outer wall of the vertical section of the high-level pipe 72 is provided with an air hole 865 connected to the corresponding oblique hole. An air pump 866 is installed on the left end of the right-side pipeline support 71 through a mounting seat. The air outlet of the air pump 866 is connected to the venting chamber 864 through an air pipe.

[0029] Both reaction tank 1 and secondary sedimentation tank 2 are equipped with hydraulic push rods 731 that drive the corresponding partition brackets 73 to move back and forth. Support slide rods 732 are installed on the lower sides of the front and rear support plates of the partition brackets 73. The support slide rods 732 slide through the corresponding pipe support seats 71, and buffer springs are sleeved on the outer wall of the support slide rods 732 between the pipe support seats 71 and the front and rear support plates.

[0030] An extension cover plate 733 is installed at the front end of the support plate of the partition bracket 73. An avoidance groove is opened on the outer side of the outer wall of the extension cover plate 733 corresponding to the backflushing and unblocking part 8. A piston rod 734 is installed on the inner wall of the front end of the extension cover plate 733. The piston rod 734 is slidably installed on the corresponding external return pipe 6, and the piston outer wall on the piston rod 734 is damped and slidably attached to the inner wall of the external return pipe 6. A check valve 61 is also installed at the end of the external return pipe 6 on the right side located in the reaction tank 1.

[0031] A connecting pipe 21 is symmetrically connected to the upper left side of the reaction tank 1. The end of the connecting pipe 21 away from the reaction tank 1 is connected to the secondary sedimentation tank 2. A base 22 is also installed on the lower front side of the anaerobic tank. The lower end of the left pipe support 71 is fixedly connected to the base plate, and the lower end of the right pipe support 71 is fixedly connected to the base 22.

[0032] In practice: First, the pipeline switching unit 7 in this application is used to quickly switch the two high-level pipes 72 when the return sludge pump 5 stops working and the inner wall of the high-level pipe 72 needs to be inspected and maintained. This allows them to alternately form a complete sludge return transport channel with the external return pipes 6 on the left and right sides, providing an uninterrupted closed flow channel for the continuous operation of the industrial wastewater treatment system and the stable return transport of activated sludge. The backflushing and unclogging unit 8 is used to perform high-pressure backflushing and unclogging of the sludge and sediment deposits attached to the inner wall of the high-level pipe 72 without dead angles after the high-level pipe 72 reaches its maintenance cycle or is switched to offline state due to abnormal flow. It also collects and centrally treats the sludge at the discharge point, thereby realizing the sludge return pipeline without disassembly throughout the entire cycle. During maintenance, the locking assembly 74 can accurately position and lock the pipeline in both working and maintenance states after switching, preventing positional shifts and misalignments caused by hydraulic impact and equipment vibration during sludge pressurization and station switching, which could lead to pressure fluctuations and cavitation damage to the return sludge pump 5. The external return pipe 6, the baffle bracket 73, and the pipeline support 71 are all in sealed sliding contact. The switching of the two high-level pipes 72 is performed by adjusting the position of the baffle bracket 73. The piston rod 734 installed on the extension cover 73 moves back and forth synchronously with the baffle bracket 73, closely following the high-level pipe 72 during operation, preventing sludge from lingering in the excess area of ​​the inner wall of the external return pipe 6 for a long time, causing deposition and blockage.

[0033] It should be noted that, in the working state, the first and last ends of the high-level pipe 72 are connected to the docking holes on the corresponding partition brackets 73. Simultaneously, since the docking holes on the partition brackets 73 are also connected to the corresponding round holes on the external return pipe 6 and the pipe support 71, the high-level pipe 72 in the working state, together with the two external return pipes 6 on the left and right, forms a complete sludge return and conveying channel. In the maintenance state, the high-level pipe 72 requires the cooperation of the backflushing and unblocking section 8 to control the mounting slides 82 on both sides to drive the corresponding inner slide plates 83 synchronously. Move the tube away from the corresponding pipe support 71 until the mud discharge hole 862 at the head of the high-level tube 72 in the maintenance state is connected to the transfer hole 861 on the corresponding pipe support 71. At the same time, make the second air hole 865 at the tail end of the high-level tube 72 in the maintenance state connected to the air passage 864 on the corresponding pipe support 71. This achieves the effect of the high-level tube 72 in the maintenance state and the two pipe supports 71 on the left and right forming a complete backflushing cleaning channel, which facilitates the subsequent backflushing cleaning of the inner wall of the high-level tube 72 through the backflushing and unblocking part 8.

[0034] In the initial state, the anaerobic, anoxic, and aerobic tanks of reaction tank 1 complete the initial water intake commissioning according to the design liquid level, and the secondary sedimentation tank 2 completes the initial calibration of the sludge-water separation interface. The baffle support 73 is positioned in the initial working position on the front side by the hydraulic push rod 731, so that the front high-level pipe 72 is in the ready-to-work state and the rear high-level pipe 72 is in the standby state. At this time, the docking hole on the baffle support 73 will be fully connected with the round hole on the external return pipe 6, the round hole on the pipe support seat 71, and the first end opening on the front high-level pipe 72. The left and right external return pipes 6 and the front high-level pipe 72 together form a complete sludge return and conveying channel to be guided. In addition, at this time, the air storage tank 742 and the receiving tank 744 on the rear side of the locking group 74 are in a positive pressure state, and the locking block 74 5. Under positive pressure, the spring tension is overcome and the receiving groove 744 extends out and is inserted into the corresponding card plate 741. The locking group 74 is fully locked, which firmly fixes the partition bracket 73 and the pipeline support 71 without axial movement or circumferential deflection. At the same time, the air pump 866 is in the depressurization and air extraction state, the electromagnet 84 and the electromagnetic collar 85 are both de-energized, the mounting slides 82 and the inner slide plate 83 on the front and rear high-level pipes 72 are all in the initial sealing position, the inner slide plate 83 completely seals the mud discharge hole 862 and the second air hole 865 on the high-level pipe 72, so that the inner cavity of the front and rear high-level pipes 72 is in a sealed state, and the mud discharge hole 862 and the transfer hole 861, the second air hole 865 and the ventilation cavity 864 are all in a completely disconnected state.

[0035] It is worth emphasizing that the check valve 61 connected in series on the external return pipe 6 connected to the reaction tank 1 is normally closed. An automatic exhaust valve with normal standby status is provided outside the highest point of the high-level pipe 72, which can automatically discharge the air accumulated in the pipeline in real time. The piston rod 734 on the extension cover plate 733 is positioned in the initial position with the partition bracket 73. The outer wall of the piston is damped and fits against the inner wall of the external return pipe 6, completely sealing the idle inner cavity of the external return pipe 6 except for the working channel, and there is no dead zone for sludge retention. It should also be noted that whenever the partition bracket 73 slides axially back and forth along the external return pipe 6, the docking hole on the partition bracket 73 can always be coaxially docked with the corresponding round hole of the external return pipe 6 and the round hole of the pipeline support seat 71, and there will be no problem of misalignment of the flow hole or sudden reduction of the flow area due to the sliding of the partition bracket 73.

[0036] In the start-up phase of wastewater biochemical treatment, the industrial wastewater to be treated is first pumped by an external inlet pump to the anaerobic, anoxic, and aerobic tanks of reaction tank 1 according to the designed flow rate. This is existing technology and will not be described in detail here. The operating liquid level of each tank is adjusted to form a preset liquid level difference between the liquid level at the end of the aerobic tank and the liquid level at the inlet of the anoxic tank, thus completing the initial water distribution of the wastewater. Subsequently, the dissolved oxygen concentration in the aerobic tank needs to be maintained within the designed range. Simultaneously, the internal return pump 3 is started to take the supernatant rich in nitrate nitrogen from the upper water collection tank / overflow port at the end of the aerobic tank and quantitatively transport it to the middle and upper part of the anoxic tank through the internal return pipe 4. This provides sufficient nitrate nitrogen for the denitrification reaction in the anoxic tank, thereby achieving the effect of gradient biochemical degradation and efficient nitrogen and phosphorus removal of wastewater.

[0037] During the stable transport stage of activated sludge external return, after the initial start-up and stable operation of the wastewater biochemical treatment are completed, the locking group 74 maintains the initial air-pressurized and locked state. The sludge return channel formed by the front high-level pipe 72 and the two external return pipes 6 on the left and right sides remains completely coaxially connected. The inner slide plate 83 completely blocks the sludge discharge hole 862 and the air hole 865, without reducing the flow area of ​​the sludge return channel. In this state, as the wastewater treated by the reaction tank 1 is stably transported to the secondary sedimentation tank 2 through the connecting pipe 21 for gravity sludge-water separation, the supernatant is discharged in compliance with standards, and the activated sludge settled at the bottom of the secondary sedimentation tank 2 is scraped to the central sludge collection hopper by the sludge scraper and flows into the low-level sludge collection well by gravity, completing the enrichment and collection of activated sludge.

[0038] It is worth emphasizing that the initial magnetic poles of electromagnet 84 are the same as those of the sector-shaped magnetic block on the mounting slide 82, and the initial magnetic poles of electromagnetic collar 85 are opposite to those of the sector-shaped magnetic block on the mounting slide 82. Furthermore, both electromagnet 84 and electromagnetic collar 85 can be bistable electromagnets, which do not require long-term energization; the magnetic poles can be changed simply by switching the current direction when energized.

[0039] Once the sludge in the secondary sedimentation tank 2 has accumulated to the designed concentration, the electromagnets 84 and electromagnetic collars 85 at both ends of the corresponding front high-level pipe 72 must be energized simultaneously. Under the combined action of the magnetic attraction of the electromagnet 84 and the magnetic repulsion of the electromagnetic collar 85, the mounting slides 82 at both ends will move synchronously along the corresponding limiting slide holes 81 towards the side closer to the corresponding pipe support 71, thereby driving the inner slide plate 83 to slide synchronously within the high-level pipe 72. If the mounting slides 82 and the inner slide plate 83 are already initially positioned close to the corresponding pipe support 71, the tight magnetic connection through the corresponding electromagnets 84 can further reinforce the set limiting positions of the mounting slides 82 and the inner slide plate 83, ensuring that the inner slide plate 83 completely blocks and seals the front high-level pipe 72. The sludge discharge hole 862 and the second air hole 865 at the tail end are then connected. The return sludge pump 5 is then started. The activated sludge enriched in the sludge collection well is pressurized by the return sludge pump 5 and flows sequentially through the left external return pipe 6, the front working high-level pipe 72, the right external return pipe 6, and the anaerobic tank end check valve 61. It is then quantitatively transported to the anaerobic tank inlet of the reaction tank 1, completing the external return transport of activated sludge. During the transport process, the check valve 61 is automatically opened under the action of the forward water flow, which does not affect the normal transport of sludge. The inverted U-shaped high liquid level design of the high-level pipe 72 forms a high-level water seal throughout the process. The automatic air vent valve can discharge the air accumulated in the pipeline in real time, completely eliminating the problem of air lock in the pipeline. The piston rod 734 always blocks the unused inner cavity of the external return pipe 6, and there is no dead zone for sludge retention.

[0040] Once the sludge return system is operating stably and the sludge concentration in the anaerobic tank is maintained within the design range, the system continues to operate under this condition until the high-level pipe 72 in the upstream working state reaches the set operating cycle or an abnormal flow resistance occurs requiring maintenance. Through the magnetic attraction between the electromagnet 84 and the electromagnetic collar 85, the sealing position of the inner slide plate 83 is double-reinforced, completely preventing leakage of the sludge discharge hole 862 and air pores caused by the displacement of the inner slide plate 83 during sludge transportation. This ensures the complete sealing of the sludge return channel and the stability of the flow area, eliminating the hidden danger of turbulent sludge accumulation. In addition, the double anti-backflow design of the inverted V-shaped high-level pipe 72 and the check valve 61 can avoid cavitation, pressure fluctuations, and insufficient flow in the sludge return structure, significantly improving the service life of the return sludge pump 5 and the stability of sludge return.

[0041] During the pipeline online switching phase, when the high-level pipe 72 in the current working state reaches the set operating cycle or an abnormal flow resistance occurs requiring maintenance, the return sludge pump 5 must first be stopped. Then, the external vacuum pump releases the pressure and exhausts the air storage tank 742 through the air hole 743 on the rear support plate, releasing the positive pressure thrust on the locking block 745. Under the action of the tension spring and the negative pressure suction, the locking block 745 completely retracts into the corresponding receiving groove 744, thereby releasing the position lock between the partition bracket 73 and the pipeline support seat 71. Then, the two hydraulic push rods 7 on the left and right sides... 31 drives the corresponding partition bracket 73 to move smoothly and synchronously to the rear along the axial direction of the external return pipe 6. The partition bracket 73 drives the support slide rod 732 to slide synchronously. The buffer spring provides bidirectional buffering and limiting during the movement until the partition bracket 73 moves to the rear switching working position, so that the first and last end ports on the rear standby high-level pipe 72 are fully connected with the docking holes on the corresponding partition bracket 73, the round holes on the external return pipe 6, and the round holes on the pipe support seat 71, respectively, forming a new closed sludge return and conveying channel, and completing the online commissioning of the standby pipeline.

[0042] When the rear high-level pipe 72 is switched to the sludge return conveying working state, it is also necessary to control the electromagnets 84 and electromagnetic collars 85 at the beginning and end of the corresponding rear high-level pipe 72 to be energized simultaneously. Under the combined action of the magnetic attraction force of the electromagnet 84 and the magnetic repulsion force of the electromagnetic collar 85, the mounting slides 82 at both ends will move synchronously towards the side closer to the corresponding pipeline support 71 along the corresponding limiting slide holes 81, thereby driving the inner slide plate 83 to slide synchronously in the high-level pipe 72. If the mounting slides 82 and the inner slide plate 83 are initially already on the side closer to the corresponding pipeline support 71, the corresponding electromagnets 84 can be tightly magnetically connected to further reinforce the set limiting position of the mounting slides 82 and the inner slide plate 83, ensuring that the inner slide plate 83 completely blocks and seals the sludge discharge hole 862 and the second air hole 865 at the beginning and end of the rear high-level pipe 72.

[0043] Subsequently, the external vacuum pump injects compressed air into the corresponding air storage tank 742 through the air hole 743 on the front support plate. Under positive pressure, the locking block 745 pushes out of the corresponding receiving slot 744 to overcome the tension of the tension spring and inserts into the insertion hole of the corresponding locking plate 741, thus completing the secure locking of the rear working position of the partition bracket 73. Finally, after the return sludge pump 5 is put into trial operation, it continues to work, and the operating pressure and flow rate of the return sludge pump 5 are monitored in real time to confirm the sealing and flow stability of the new sludge return channel.

[0044] Since the front high-level pipe 72, which was originally in working condition, is completely disconnected from the sludge return channel and switched to offline maintenance, as the partition bracket 73 moves to the rear, the extension cover 733 will drive the piston rod 734 to move to the rear in sync, so that the piston of the piston rod 734 is always in contact with the inner wall of the outer return pipe 6 and follows the new working channel position, dynamically sealing the new idle inner cavity in the outer return pipe 6, and eliminating the dead zone of sludge retention throughout the process.

[0045] It enables seamless online switching of sludge return pipelines without shutdown. Only a short pause of the return sludge pump 5 is needed to complete the seamless switching between the working pipeline and the standby pipeline. There is no need to stop the wastewater treatment operation of the biological system. It completely solves the industry pain point that the maintenance of traditional single pipeline design requires a complete shutdown of the entire line. It ensures the continuous operation of the wastewater treatment system and avoids the risk of effluent quality exceeding standards and environmental violations. The pneumatic locking design of the locking group 74 can quickly and firmly lock the baffle bracket 73 after switching, avoiding pipeline movement and misalignment caused by hydraulic impact and equipment vibration during sludge transportation, and ensuring the long-term stability of the return system.

[0046] It should be noted that if there is a large amount of residual sludge in the vertical section of the high-level pipe 72, which may affect the subsequent backflushing and dredging effect, the return sludge pump 5 can be briefly reversed and run at a low speed for an appropriate time before the pipeline switching step. This will allow the residual sludge and minor blockages in the front high-level pipe 72 to be pumped back into the sludge collection well below the secondary sedimentation tank 2. After the vertical section of the high-level pipe 72 is completely emptied, the return sludge pump 5 can be stopped, and the check valve 61 will automatically close simultaneously to prevent backflow of media from the anaerobic tank side. During this period, after the return sludge pump 5 is stopped, the inner slide plate 83 can be left stationary for an appropriate time to allow the small amount of media remaining in the vertical section of the high-level pipe 72 to flow completely into the cavity of the right-side external return pipe 6 under gravity. After the gravity-assisted bottom emptying is completed, the subsequent pipeline switching operation can be performed.

[0047] During the offline pipeline backflushing and sludge centralized recovery stage, after completing the online switching of the high-level pipe 72 and the commissioning of the standby pipeline, for the front high-level pipe 72 switched to maintenance status, it is necessary to control the electromagnetic collars 85 at the beginning and end of the corresponding front high-level pipe 72 to change the current circulation direction. At this time, the magnetic poles of the electromagnet 84 will change to be opposite to the magnetic poles of the sector-shaped magnetic blocks on the mounting slide 82, and the magnetic poles of the electromagnetic collar 85 will change to be the same as the magnetic poles of the sector-shaped magnetic blocks on the mounting slide 82. Under the combined action of the magnetic repulsion of the electromagnet 84 and the magnetic attraction of the electromagnetic collar 85, the mounting slides 82 at both ends will move synchronously away from the corresponding pipeline support 71 along the corresponding limiting sliding holes 81, thereby driving the inner slide plate 83 to slide synchronously inside the high-level pipe 72 until the mounting slide 82 is tightly magnetically connected. The suction connection is attached to the corresponding electromagnetic collar 85, further reinforcing the set limit position of the mounting slide 82 and the inner slide plate 83, ensuring that the inner slide plate 83 completely releases the state of the mud discharge hole 862 and the second air hole 865 at the beginning and end of the front high-level pipe 72, which was previously blocked. At this time, the mud discharge hole 862 at the beginning of the front high-level pipe 72 is fully connected with the transfer hole 861 on the left pipeline support 71, and the second air hole 865 at the end of the front high-level pipe 72 is fully connected with the venting chamber 864 on the right pipeline support 71, forming a complete closed backflushing cleaning channel. By switching the magnetic poles of the electromagnet 84 and the electromagnetic collar 85, the backflushing cleaning channel can be quickly opened and reset without disassembling the pipeline, greatly reducing the maintenance labor intensity and downtime, and realizing the pipeline's non-disassembly full life cycle maintenance.

[0048] Next, high-pressure airflow is delivered to the ventilation chamber 864 via the air pump 866 through the air pipe, and then enters the front high-level pipe 72 under maintenance through the second air hole 865 connected to the ventilation chamber 864. The high-pressure airflow flows at high speed from the tail end to the head end along the inner cavity of the high-level pipe 72, powerfully flushing and peeling off the sludge and deposited hardened material attached to the inner wall of the high-level pipe 72, thereby achieving a complete dredging of the inner wall of the front high-level pipe 72. Subsequently, the high-pressure airflow carries the peeled residual sludge through the sludge discharge hole 862 on the front high-level pipe 72 and the transfer hole 861 connected to the corresponding sludge discharge hole 862, and enters the collection box 863. The vent of the collection box 863 discharges clean airflow, and the sludge is completely intercepted and collected in the collection box 863. Depending on the working conditions, it is selected to be returned to the anaerobic tank on the reaction tank 1 or the secondary sedimentation tank 2. After the backflushing and dredging work is completed, the air pump 866 is turned off, and the front high-level pipe 72 is controlled again. The electromagnet 84 and the electromagnetic collar 85 are energized to change the direction of the current circulation, driving the mounting slide 82 to move the inner slide plate 83 closer to the corresponding pipeline support 71 to restore its original position. This re-seals the sludge discharge hole 862 and the second air hole 865 on the front high-level pipe 72, restoring the high-level pipe 72 to its intact standby state. The reverse high-pressure airflow backflushing design achieves thorough flushing of the inner wall of the offline high-level pipe 72 without dead angles, completely removing attached sludge and stubborn caking, fully restoring the pipeline's designed flow capacity. At the same time, no clean water is consumed, avoiding water waste and preventing sludge dilution from affecting subsequent resource utilization. Furthermore, the fully enclosed backflushing and sludge recycling design ensures that all sludge generated by backflushing is intercepted in the collection box 863 for centralized treatment and can be directly returned to the biological system for secondary utilization, completely avoiding pollution and secondary pollution caused by sludge overflow, improving the utilization rate of activated sludge, and reducing sludge disposal costs.

[0049] During the continuous operation phase of the system, when the high-level pipe 72 in the rear working state reaches the set operating cycle or the front backup pipe has completed maintenance and dredging, the return sludge pump 5 must first be stopped. Then, the external vacuum pump releases the pressure and exhausts the corresponding air storage tank 742 through the air hole 743 on the front support plate, releasing the position lock of the partition bracket 73. Next, the two hydraulic push rods 731 on the left and right sides drive the corresponding partition brackets 73 to move forward synchronously, restoring them to their original positions and initial working positions, so that the high-level pipe 72, which has completed dredging, is switched back to the working state. The rear high-level pipe 72 is switched to standby mode; the baffle bracket 73 is relocked, and the sealing, backflow prevention and flow stability of the return channel are confirmed. At the same time, the above-mentioned backflushing and unblocking operation steps are performed on the rear high-level pipe 72, which has been switched to standby mode, to complete the rotation maintenance of the pipeline and realize the continuous operation of the system. The design of alternating operation and unblocking of the dual pipelines with one in use and one in standby mode realizes the maintenance-free operation of the sludge return pipeline throughout its entire life cycle, greatly extends the continuous operation cycle of the system, reduces equipment maintenance downtime, and improves the annual operating time and treatment efficiency of the wastewater treatment system.

[0050] It is worth emphasizing that when the high-level pipe 72 experiences sudden malfunctions such as blockage or leakage, or when the return sludge pump 5 experiences a sudden shutdown or power failure, the check valve 61 at the anaerobic tank end will close in time to complete the first-level backflow prevention, the return sludge pump 5 will close simultaneously to complete the second-level backflow prevention, and the inverted V-shaped water seal of the high-level pipe 72 will simultaneously form the third-level physical blockage. This triple protection eliminates the risk of backflow. At the same time, the above-mentioned online pipeline switching operation steps can be directly executed to complete the offline isolation of the faulty pipeline and the commissioning of the backup pipeline within seconds, without stopping the system operation, thus avoiding system shutdown and environmental accidents caused by the expansion of the fault.

[0051] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions will not cause the essence of the corresponding technical solutions to deviate from the protection scope of the technical solutions of the embodiments of the present invention.

Claims

1. An industrial wastewater treatment system with a closed-loop sludge recirculation structure, characterized in that, include: The bottom plate has a secondary sedimentation tank (2) and a reaction tank (1) installed on the left and right sides of the upper end of the bottom plate, respectively. The reaction tank (1) consists of an anaerobic tank, an anoxic tank and an aerobic tank. The anoxic tank and the aerobic tank are connected by an internal return pipe (4) on the outer wall of the rear end. An internal return pump (3) is installed on the outer wall of the rear end of the reaction tank (1) to connect with the internal return pipe (4) and to transport the nitrified liquid at the end of the aerobic tank to the inlet of the anoxic tank. External return pipes (6) are installed through the lower side of the reaction tank (1) and the secondary sedimentation tank (2), respectively. The external return pipe (6) is an L-shaped design with a solid tail. A return sludge pump (5) is installed at the lower end of the bottom plate below the reaction tank (1) to connect with the left external return pipe (6) and to transport the bottom sludge to the anaerobic tank. A pipeline switching part (7) is set on the left and right external return pipes (6), and a backflushing and unblocking part (8) is set on the pipeline switching part (7). The pipeline switching part (7) includes a partition bracket (73) that is slidably sleeved on the external return pipe (6). The partition bracket (73) consists of two front and rear support plates and a sleeve. Pipeline support seats (71) are slidably sleeved on the outer walls of the left and right sleeves respectively. High-level pipes (72) are symmetrically and detachably installed on the left and right pipeline support seats (71). The high-level pipes (72) consist of an inclined section and a vertical section. Locking groups (74) are provided on the pipeline support seats (71) and the partition bracket (73).

2. The industrial wastewater treatment system with a closed sludge recirculation structure according to claim 1, characterized in that: The backflushing and unblocking section (8) includes a limiting sliding hole (81) on the outer wall of the inclined section and the vertical section of the high-level pipe (72). The limiting sliding hole (81) is waist-shaped. An installation slide (82) is slidably installed on the inner wall of the limiting sliding hole (81). The installation slide (82) is composed of a waist-shaped slider and a fan-shaped magnetic block. An inner sliding plate (83) is installed at the end of the waist-shaped slider away from the fan-shaped magnetic block and is slidably connected to the inner wall of the high-level pipe (72). The inner sliding plate (83) is a hollow tubular structure. An electromagnet (84) is installed on the upper end of the pipeline support (71) corresponding to the two high-level pipes (72) before and after. An electromagnetic collar (85) is fixedly sleeved on the outer wall of the inclined section of the high-level pipe (72) above the limiting sliding hole (81). A backflushing collection group (86) is jointly provided on the pipeline support (71) and the high-level pipe (72).

3. The industrial wastewater treatment system with a closed sludge recirculation structure according to claim 1, characterized in that: The outer wall of the external return pipe (6) is provided with round holes corresponding to the two front and rear high-level pipes (72). The outer wall of the upper end of the pipe support (71) is also provided with round holes corresponding to the two front and rear high-level pipes (72). The outer wall of the sleeve of the partition bracket (73) is provided with a connecting hole corresponding to the round hole. The first end and the last end of the high-level pipe (72) are respectively connected to the round hole of the corresponding pipe support (71).

4. The industrial wastewater treatment system with a closed sludge recirculation structure according to claim 1, characterized in that: The locking assembly (74) includes a locking plate (741) that is integrally installed at both ends of the pipeline support base (71). Several locking plates (741) are installed, and the several locking plates (741) are evenly distributed in a circle. The locking plate (741) is an arc-shaped plate structure with a hole in the middle. The front and rear support plates of the partition bracket (73) are provided with air storage grooves (742). The air storage grooves (742) are annular. The upper end of the support plate is provided with an air hole (743) that connects to the corresponding air storage groove (742).

5. The industrial wastewater treatment system with a closed sludge recirculation structure according to claim 4, characterized in that: The locking assembly (74) also includes a receiving groove (744) located on the inner wall of the circular support plate corresponding to the insertion hole. Several receiving grooves (744) are provided, and the several receiving grooves (744) are evenly distributed around the circumference. The receiving grooves (744) are connected to the gas storage tank (742). The receiving grooves (744) and the inner wall of the gas storage tank (742) are slidably installed with a locking block (745) through a tension spring. The several receiving grooves (744) and the several locking plates (741) are staggered.

6. The industrial wastewater treatment system with a closed sludge recirculation structure according to claim 2, characterized in that: The backwash collection group (86) includes a transfer hole (861) on the left pipeline support (71) corresponding to both the front and rear high-level pipes (72). A mud discharge hole (862) connected to the corresponding transfer hole (861) is opened on the outer wall of the inclined section of the high-level pipe (72). A collection box (863) with a vent hole is installed on the right end of the left pipeline support (71). Both the front and rear transfer holes (861) are connected to the collection box (863).

7. The industrial wastewater treatment system with a closed sludge recirculation structure according to claim 6, characterized in that: The backflush collection group (86) also includes a ventilation chamber (864) located on the right-side pipeline support (71) corresponding to the two front and rear high-level pipes (72). The ventilation chamber (864) consists of two front and rear oblique holes and a connecting groove. The outer wall of the vertical section of the high-level pipe (72) is provided with a second air hole (865) connected to the corresponding oblique hole. An air pump (866) is installed on the left end of the right-side pipeline support (71) through a mounting seat. The air outlet of the air pump (866) is connected to the ventilation chamber (864) through an air pipe.

8. The industrial wastewater treatment system with a closed sludge recirculation structure according to claim 1, characterized in that: Hydraulic push rods (731) for driving the corresponding partition brackets (73) to move back and forth are installed through the lower side of both the reaction tank (1) and the secondary sedimentation tank (2). Support slide rods (732) are installed on the lower side of the front and rear support plates on the partition brackets (73). The support slide rods (732) slide through the corresponding pipeline support base (71), and buffer springs are sleeved on the part of the outer wall of the support slide rods (732) between the pipeline support base (71) and the front and rear support plates.

9. The industrial wastewater treatment system with a closed sludge recirculation structure according to claim 8, characterized in that: The front end of the support plate of the partition bracket (73) is equipped with an extension cover plate (733). The outer side of the outer wall of the extension cover plate (733) is provided with a clearance groove corresponding to the backflushing and unblocking part (8). A piston rod (734) is installed on the inner wall of the front end of the extension cover plate (733). The piston rod (734) is slidably installed on the corresponding external return pipe (6). The piston outer wall of the piston rod (734) is damped and slidably attached to the inner wall of the external return pipe (6). A check valve (61) is also installed at one end of the external return pipe (6) on the right side inside the reaction tank (1).

10. An industrial wastewater treatment system with a closed sludge recirculation structure according to claim 8, characterized in that: The reaction tank (1) has a connecting pipe (21) symmetrically connected to the upper left side. The end of the connecting pipe (21) away from the reaction tank (1) is connected to the secondary sedimentation tank (2). A base (22) is also installed on the lower front side of the anaerobic tank. The lower end of the pipeline support seat (71) on the left side is fixedly connected to the base plate, and the lower end of the pipeline support seat (71) on the right side is fixedly connected to the base (22).

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