Side flow enhanced deslagging sand system and sewage treatment system for biochemical unit of sewage treatment plant

Abstract

The application discloses a sewage treatment plant biochemical unit side flow reinforced deslagging sand system and a sewage treatment system, relates to the technical field of sewage treatment, and comprises a pumping device, a mesh belt type deslagging sand integrated separation device, a deslagging sand conveying device, a microporous pressing device and a sludge backflow system. Sludge in a biochemical tank is conveyed to the sludge backflow system, the pumping device conveys sludge with deslagging sand in the sludge backflow system to the mesh belt type deslagging sand integrated separation device, a rotating mesh belt is arranged in the mesh belt type deslagging sand integrated separation device, the deslagging sand conveying device is used for conveying deslagging sand filtered out of the mesh belt type deslagging sand integrated separation device to the microporous pressing device, the microporous pressing device performs pressing dewatering on the filtered deslagging sand, a sludge outlet of the mesh belt type deslagging sand integrated separation device is connected to the sludge backflow system, and the sludge backflow system can convey filtered sludge back to the biochemical tank. The application does not need to stop production and has a good removal effect on suspended pollutants in activated sludge.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, and in particular to a side-flow enhanced slag and sand removal system for a biochemical unit in a wastewater treatment plant and a wastewater treatment system. Background Technology

[0002] Due to factors such as surface water inflow and groundwater infiltration, poor septic tank operation, and suspended solids deposition in drainage pipes, wastewater treatment plants often have a large amount of fine sludge and sand in their influent. Existing wastewater treatment plants generally suffer from poor treatment of fine sludge and sand, leading to low overall efficiency in the wastewater treatment process. This results in problems such as severely damaged wastewater pump impellers, pump entanglement and severe blockage; large amounts of sand deposited in the biological treatment tank, reducing the effective tank volume, burying aeration heads, and significantly reducing operating efficiency; excessive inorganic particles entering the biological treatment tank, leading to decreased sludge activity, increased sludge concentration, and increased excess sludge. This also causes excessive solids load in the secondary sedimentation tank, increased suspended solids in the effluent, and increased operating costs for subsequent advanced treatment units. In particular, in the MBR process, fine sludge, hair, and fibers entering the membrane tank cause membrane filament entanglement and blockage, increasing the difficulty of cleaning membrane modules, reducing their service life, and decreasing water flux.

[0003] Existing wastewater treatment plants typically use fine screens, aerated grit chambers, or cyclone grit chambers to treat sludge and sand in the influent. Screens have relatively low treatment precision; fine screens generally have a precision of 3-5mm and are easily entangled and clogged by hair and fibers. Aerated grit chambers separate inorganic particles and organic matter through the principle of creating a swirling flow with aeration. However, in actual operation, the aeration rate is difficult to control. Insufficient aeration cannot guarantee a sufficient swirling velocity, resulting in poor sand-water separation; excessive aeration is ineffective for removing fine sand and also increases dissolved oxygen in the water, affecting the operation of anaerobic / anoxic units. The treatment effect of cyclone grit chambers or hydrocyclones is strongly dependent on flow velocity and flow pattern. Because the influent flow velocity in wastewater treatment plants is constantly changing, the actual sand removal efficiency of cyclone grit removal facilities is very low. Therefore, it is difficult to achieve good sludge and sand treatment results using conventional treatment processes, and existing wastewater treatment plants lack sufficient funds and shutdown conditions for complete replacement or upgrading of pretreatment facilities. Therefore, there is an urgent need for a side-flow enhanced slag and sand removal system and a wastewater treatment system for the biochemical unit of a wastewater treatment plant to solve the above-mentioned technical problems. Summary of the Invention

[0004] The purpose of this invention is to provide a side-flow enhanced slag and sand removal system for the biochemical unit of a wastewater treatment plant and a wastewater treatment system, so as to solve the problems existing in the prior art, without the need for production shutdown and with good removal effect on suspended pollutants in activated sludge.

[0005] To achieve the above objectives, the present invention provides the following solution: This invention provides a side-flow enhanced sludge and sand removal system for a wastewater treatment plant's biological treatment unit, comprising a pumping device, a mesh belt integrated sludge and sand separation device, a sludge and sand conveying device, a microporous pressing device, and a sludge return system. Sludge from the biological treatment tank can be conveyed to the sludge return system. The pumping device conveys sludge containing sludge and sand from the sludge return system to the mesh belt integrated sludge and sand separation device. The mesh belt integrated sludge and sand separation device is equipped with a rotating mesh belt. The sludge outlet of the mesh belt integrated sludge and sand separation device is connected to the sludge and sand conveying device. The sludge and sand conveying device transports the filtered sludge and sand to the microporous pressing device, which presses and dewaters the filtered sludge and sand. The sludge outlet of the mesh belt integrated sludge and sand separation device is connected to the sludge return system, which can transport the filtered sludge back to the biological treatment tank.

[0006] In some embodiments, an automatic control system is also included, which is electrically connected to the controllers of the pumping device, the mesh belt integrated slag and sand separation device, the slag and sand conveying device, the microporous pressing device, and the working elements within the sludge return system.

[0007] In some embodiments, the sludge return system includes a sludge return pump and a sludge return channel. The sludge return pump can transport the sludge in the biological treatment tank to the sludge return channel, and the pumping device can pump the sludge in the sludge return channel to the mesh belt integrated slag and sand separation device.

[0008] In some embodiments, a rinsing system is also included, which includes a buffer tank, a high-pressure rinsing pump, and electrically controlled valves. The inlet of the high-pressure rinsing pump is connected to the buffer tank, and the high-pressure rinsing pump is provided with multiple outlets, each of which is equipped with an electrically controlled valve. The high-pressure rinsing pump is used to rinse the rotating conveyor belt and the filter screen in the microporous pressing device. The controller of the high-pressure rinsing pump and the electrically controlled valves are both electrically connected to the automatic control system.

[0009] In some embodiments, the height of the integrated mesh belt slag and sand separation device is higher than the height of the sludge return channel, and the sludge filtered by the integrated mesh belt slag and sand separation device can return to the sludge return channel by its own weight.

[0010] In some embodiments, the integrated mesh belt slag and sand separation device uses a polymer mesh belt as the filter medium, with a filter pore size of 300-800μm, and rotates in an elliptical pattern, with a surface hydraulic load of not less than 100m. 3 / m 2 ·h.

[0011] In some embodiments, the slag and sand conveying device adopts a shaftless spiral type or a belt conveyor type, and is provided with a drain outlet at the bottom.

[0012] In some embodiments, the microporous pressing device is a screw press or a pneumatic press, with a pressing precision of 200-500 μm.

[0013] In some embodiments, the filter screen in the microporous pressing device is a wedge-shaped filter screen.

[0014] This invention also provides a wastewater treatment system, including raw water, a pretreatment tank, an anaerobic tank, an anoxic tank, an aerobic tank, an MBR membrane tank, and a wastewater treatment plant biochemical unit side-flow enhanced sludge removal system as described above. The raw water sequentially enters the pretreatment tank, the anaerobic tank, the anoxic tank, the aerobic tank, and the MBR membrane tank. The sludge from the aerobic tank can be returned to the anoxic tank or the anaerobic tank through a first return pipe, and the sludge from the MBR membrane tank can be returned to the aerobic tank through a second return pipe. The sludge treated by the wastewater treatment plant biochemical unit side-flow enhanced sludge removal system is the sludge in the first return pipe or the sludge in the second return pipe.

[0015] The present invention achieves the following technical effects compared to the prior art: The wastewater treatment plant biochemical unit side-flow enhanced sludge and sand removal system provided by this invention adopts a side-flow bypass treatment architecture. A portion of the activated sludge containing sludge and sand is extracted from the sludge return system for sludge removal and purification. The entire system is integrated as an external unit into the existing biochemical system, eliminating the need for large-scale modifications to the original biochemical tank structures. The wastewater treatment plant can complete the installation and operation without interrupting production, avoiding wastewater treatment interruptions and production losses due to shutdowns. It is particularly suitable for upgrading existing wastewater treatment plants, with low implementation thresholds and strong adaptability. Dynamic filtration is achieved through a rotating mesh belt inside the integrated mesh belt sludge and sand separation device. The pumped sludge containing slag and sand is screened by a rotating mesh belt. The activated sludge flocs can pass smoothly through the filter screen and return to the sludge return system via the sludge outlet. From there, they are sent back to the biological treatment tank to continue participating in the biological reaction. Suspended impurities such as sand, hair, fibers, and solid grease in the sludge are effectively intercepted and separated by the rotating mesh belt, resulting in good removal of suspended pollutants within the sludge system. This continuously removes inorganic inert impurities from the activated sludge, preventing the continuous accumulation of pollutants such as slag, sand, and hair within the biological treatment tank. This improves the sludge activity in the biological treatment unit, inhibits abnormal sludge increases, reduces the solids load in the secondary sedimentation tank, reduces suspended solids in the effluent, and alleviates the operational pressure on subsequent advanced treatment units. For MBR processes, hair, fibers, and fine sand are pre-intercepted and removed, preventing them from entering the membrane tank. This alleviates membrane filament entanglement and pore blockage problems at the source, reduces the frequency of membrane module cleaning, extends the service life of the membrane modules, and ensures stable water flux in the membrane system. The slag and impurities trapped by the rotating mesh belt are sent to the slag and sand conveying device through the slag outlet, and then transferred to the microporous pressing device for pressing and dewatering. The solid slag and sand after pressing can be directly transported off-site for disposal. The filtrate produced by pressing is discharged separately and will not return to the biological system. This achieves the complete removal of slag and sand impurities from the sewage treatment system, reduces the accumulation of inert inorganic components in the biological system, reduces the production of residual sludge in the system, reduces the total amount of sludge to be treated and disposed of, and saves on sludge transportation and disposal costs. Attached Figure Description

[0016] 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.

[0017] Figure 1 This is a schematic diagram of the layout of a wastewater treatment system in some embodiments of the present invention; Figure 2 This is a schematic diagram of the arrangement of the flushing system in some embodiments of the present invention; Figure 3 This is a schematic diagram of the sludge return system layout in some embodiments of the present invention; Figure 4This is a first-angle schematic diagram of the on-site process implementation of the wastewater treatment system in some embodiments of the present invention; Figure 5 This is a second-angle schematic diagram of the on-site process implementation of the wastewater treatment system in some embodiments of the present invention.

[0018] In the diagram: 101-Sewage treatment plant biochemical unit side-flow enhanced slag and sand removal system; 1-Wire mesh belt integrated slag and sand separation device; 2-Slag and sand conveying device; 3-Microporous pressing device; 4-Sludge return system; 41-Sludge return pump; 42-Sludge return channel; 5-Flushing system; 51-Buffer tank; 52-High-pressure flushing pump; 53-Electrically controlled valve; 54-Backwashing main pipe; 6-Pumping device; 7-Automatic control system; 8-Raw water; 9-Pretreatment tank; 10-Anaerobic tank; 11-Anoxic tank; 12-Aerobic tank; 13-MBR membrane tank; 14-Waste liquid storage tank; 15-Presser operating platform; 16-Slag and sand bucket. Detailed Implementation

[0019] 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.

[0020] The purpose of this invention is to provide a side-flow enhanced slag and sand removal system for the biochemical unit of a wastewater treatment plant and a wastewater treatment system, so as to solve the problems existing in the prior art, without the need for production shutdown and with good removal effect on suspended pollutants in activated sludge.

[0021] 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.

[0022] Example 1 like Figures 1-5As shown, the present invention provides a side-flow enhanced slag and sand removal system 101 for a biochemical unit in a wastewater treatment plant, including a pumping device 6, a mesh belt integrated slag and sand separation device 1, a slag and sand conveying device 2, a microporous pressing device 3, and a sludge return system 4. The sludge in the biochemical tank (aerobic tank 12, MBR membrane reactor 13) can be conveyed to the sludge return system 4. The pumping device 6 conveys the sludge containing slag and sand in the sludge return system 4 to the mesh belt integrated slag and sand separation device 1. The mesh belt integrated slag and sand separation device 1 is equipped with a rotating mesh belt. The slag outlet of the mesh belt integrated slag and sand separation device 1 is connected to the slag and sand conveying device 2. The slag and sand conveying device 2 is used to transport the filtered slag and sand to the microporous pressing device 3. The microporous pressing device 3 is used to press and dewater the filtered slag and sand. The sludge outlet of the mesh belt integrated slag and sand separation device 1 is connected to the sludge return system 4. The sludge return system 4 can transport the filtered sludge back to the biochemical tank.

[0023] Employing a side-flow bypass treatment architecture, a portion of activated sludge containing slag and sand is extracted from the sludge return system 4 for sludge removal and purification. The entire system is integrated as an external unit into the existing biological treatment system, eliminating the need for large-scale modifications to the original biological treatment tank structures. The wastewater treatment plant can complete the installation and operation without interrupting production, avoiding wastewater treatment interruptions and production losses due to shutdowns and modifications. This approach is particularly suitable for upgrading existing wastewater treatment plants, offering low implementation barriers and strong adaptability. Dynamic filtration is achieved through the rotating mesh belt inside the integrated mesh belt slag and sand separation device 1. The pumped sludge containing slag and sand is screened by a rotating mesh belt. The activated sludge flocs can pass smoothly through the filter screen and return to the sludge return system 4 via the sludge outlet. From there, they are sent back to the biological treatment tank to continue participating in the biological reaction. Suspended impurities such as sand, hair, fibers, and solid grease in the sludge are effectively intercepted and separated by the rotating mesh belt, resulting in good removal of suspended pollutants within the sludge system. This continuously removes inorganic inert impurities from the activated sludge, preventing the continuous accumulation of pollutants such as slag, sand, and hair within the biological treatment tank. This improves the sludge activity in the biological treatment unit, inhibits abnormal sludge increases, reduces the solids load in the secondary sedimentation tank, reduces suspended solids in the effluent, and alleviates the operational pressure on subsequent advanced treatment units. For MBR processes, hair, fibers, and fine sand are pre-intercepted and removed, preventing them from entering the membrane tank. This alleviates membrane filament entanglement and pore blockage problems at the source, reduces the frequency of membrane module cleaning, extends the service life of the membrane modules, and ensures stable water flux in the membrane system. The slag and impurities trapped by the rotating mesh belt are sent to the slag and sand conveying device 2 through the slag outlet, and then transferred to the microporous pressing device 3 for pressing and dewatering. The solid slag and sand after pressing can be directly transported off-site for disposal. The filtrate produced by pressing is discharged separately and will not return to the biological system. This achieves the complete removal of slag and sand impurities from the sewage treatment system, reduces the accumulation of inert inorganic components in the biological system, reduces the production of residual sludge in the system, reduces the total amount of sludge to be treated and disposed of, and saves sludge transportation and disposal costs.

[0024] In some embodiments, the wastewater treatment plant's biochemical unit side-flow enhanced slag and sand removal system 101 further includes an automatic control system 7. The automatic control system 7 is electrically connected to the controllers of the pumping device 6, the mesh belt integrated slag and sand separator 1, the slag and sand conveying device 2, the microporous pressing device 3, and the controllers of the working elements within the sludge return system 4. The automatic control system 7 establishes electrical signal connections with all core equipment and the working elements of the sludge return system 4, enabling independent control of each pumping device 6, mesh belt integrated slag and sand separator 1, slag and sand conveying device 2, and microporous pressing device 3. It can independently control the start / stop, operating speed, and working interval of a single device, facilitating individual device commissioning and maintenance. During maintenance, the corresponding device can be shut down individually without forcing the entire system to stop. The automatic control system 7 can realize logical interlocking of various equipment according to the sludge operating conditions: for example, after the pumping device 6 starts to take sludge, the mesh belt integrated slag and sand separation device 1, slag and sand conveying device 2, and microporous pressing device 3 are started in sequence; when stopping, they are shut down in reverse order to avoid the failure of slag and sand accumulation and blockage caused by the feeding equipment running but the slag and pressing device not being turned on. This ensures the timing matching of the entire sludge removal process, improves the reliability of system operation, and reduces manual operation intervention. When the working components such as pumps and valves of the pumping device 6, mesh belt integrated slag and sand separation device 1, slag and sand conveying device 2, microporous pressing device 3, or sludge return system 4 malfunction, the control system can issue liquid level alarms, equipment failures, and maintenance prompts after receiving the fault electrical signals. This makes it easier for operation and maintenance personnel to find and locate the fault point in time, reduce the risk of equipment damage and system failure, and reduce the workload of on-site inspection.

[0025] In some embodiments, the sludge return system 4 includes a sludge return pump 41 and a sludge return channel 42. The sludge return pump 41 can transport the sludge from the biological treatment tank to the sludge return channel 42, and the pumping device 6 can pump the sludge in the sludge return channel 42 to the mesh belt integrated slag and sand separator 1. The activated sludge output from the biological treatment tank first collects in the sludge return channel 42, where the sludge is mixed and homogenized. This makes the sludge concentration and slag and sand impurities extracted by the pumping device 6 relatively stable, avoiding the problem of large fluctuations in sludge material caused by directly taking sludge from local points in the biological treatment tank. This is beneficial to the stable filtration operation of the mesh belt integrated slag and sand separator 1 and improves the slag and sand removal effect. The sludge return pump 41 maintains a high-flow sludge return rate for the normal operation of the biological treatment system, ensuring that the return ratio of existing biological treatment processes such as anoxic-aerobic and MBR remains intact. The pumping device 6 only draws a portion of the sludge from the sludge return channel 42 into the side-flow enhanced sludge and sand removal system 101 of the wastewater treatment plant's biological unit for side-flow treatment. This bypass diversion mode does not interrupt the sludge circulation within the biological treatment tank and does not affect the normal operation of the main wastewater treatment process. After the pumping device 6 draws sludge containing sludge and sand from the sludge return channel 42 for filtration and impurity removal, the purified sludge is returned to the sludge return channel 42 and then sent back to the biological treatment tank following the original return flow. The purified sludge returns to the return channel and then into the biological treatment tank; the path is smooth, eliminating the need for new, longer sludge return pipelines, simplifying pipeline layout, and reducing equipment investment and the risk of pipeline blockage.

[0026] In some embodiments, the wastewater treatment plant's biochemical unit side-flow enhanced slag and sand removal system 101 further includes a flushing system 5. The flushing system 5 includes a buffer tank 51, a high-pressure flushing pump 52, and an electrically controlled valve 53. The inlet of the high-pressure flushing pump 52 is connected to the buffer tank 51. The high-pressure flushing pump 52 is provided with multiple outlets, each of which is equipped with an electrically controlled valve 53. The high-pressure flushing pump 52 is used to flush the rotating conveyor belt and the filter screen in the microporous pressing device 3. Specifically, flushing water is delivered through the backwashing main pipe 54. The controller of the high-pressure flushing pump 52 and the electrically controlled valve 53 are both electrically connected to the automatic control system 7. The buffer tank 51 serves as a water storage and pressure stabilization buffer, which can stably supply water to the high-pressure flushing pump 52, reduce the impact of water pressure fluctuations in the external water supply network, ensure stable water volume and pressure in the high-pressure flushing pump 52, and avoid a decrease in flushing force due to insufficient water supply, thus ensuring the reliability of flushing the rotating conveyor belt and the filter screen of the microporous pressing device 3. At the same time, the tank can be equipped with a liquid level detection system to realize early warning of water shortage. The high-pressure flushing pump 52 is equipped with multiple independent outlets, each with an independent electrically controlled valve 53. This allows for differentiated flushing control at different points, enabling the individual opening of the corresponding electrically controlled valve 53 to flush the rotating conveyor belt and the internal filter screen of the microporous pressing device 3. Simultaneous flushing of both areas is possible, or individual flushing can be performed based on the equipment's operating conditions, eliminating the need for continuous high-flow flushing and effectively saving flushing water consumption. The high-pressure flushing pump 52 and all electrically controlled valves 53 are connected to the automatic control system 7, achieving automated linkage of flushing operations. The control system automatically controls the start and stop of the high-pressure flushing pump 52 and the opening and closing of each electrically controlled valve 53 based on the conveyor belt's operating time and the pressing device's working status, matching the working sequence of filtration and pressing without manual on-site operation. It can also be linked with the start and stop of the entire wastewater treatment plant's biochemical unit side-flow enhanced slag and sand removal system 101, performing flushing synchronously during equipment operation and enhanced cleaning as needed after shutdown. Real-time high-pressure washing of the rotating mesh belt can promptly remove sludge, hair, and slag adhering to the mesh belt, preventing the mesh belt filter holes from being blocked by pollutants and continuously ensuring the filtration throughput and slag removal efficiency of the mesh belt; washing the internal filter screen of the microporous pressing device 3 can wash away the fibers and fine particles embedded in the screen gaps, avoid the pressing filter screen from becoming clogged and ineffective, ensure stable pressing and dewatering effect, and reduce the frequency of manual disassembly and cleaning of the filter screen.

[0027] It should be noted that the water source for rinsing can be wastewater from the sewage treatment plant or tap water. The slag and sand separated by the mesh belt integrated slag and sand separator 1 fall into the slag and sand conveying device 2, and are then transported to the microporous pressing device 3 for pressing and dewatering. The dewatered screenings are stored in the slag and sand bucket 16 for final off-site disposal. To ensure that the slag discharged from the microporous pressing device 3 falls into the slag and sand bucket 16 by gravity, a pressing machine operating platform 15 can be built, and the microporous pressing device 3 can be installed on the pressing machine operating platform 15. The pressing filtrate flows by gravity to the sewage treatment plant's drainage network. If the drainage network inlet is far away, a waste liquid storage tank 14 can be installed for temporary storage of the filtrate and drainage from the rinsing system 5. The automatic control system 7 is installed near the steel structure platform to facilitate the electrical signal access of all equipment, thereby controlling each electrical device.

[0028] In some embodiments, the height of the integrated mesh belt sludge and sand separation device 1 is higher than the height of the sludge return channel 42, allowing the filtered sludge to return to the sludge return channel 42 by gravity. The treated activated sludge returns to the sludge return channel 42 by gravity, eliminating the need for an additional sludge transfer pump, reducing the need for return lifting equipment and associated power supply and control pipelines, thus reducing hardware investment and lowering the energy consumption of the entire wastewater treatment plant's biochemical unit side-flow enhanced sludge and sand removal system 101, achieving energy-saving operation. Specifically, the integrated mesh belt sludge and sand separation device 1 is installed on a steel structure platform, ensuring sufficient elevation to allow the effluent to return to the biochemical tank by gravity. The steel structure platform is erected next to the sludge return channel 42, and the pumping device 6 is installed inside the sludge return channel 42, connected to the inlet of the integrated mesh belt sludge and sand separation device 1 via an inlet pipe.

[0029] In some embodiments, the integrated slag and sand separation device 1 uses a polymer mesh belt as the filter medium, with a pore size of 300-800 μm, and rotates in an elliptical pattern, with a surface hydraulic load of not less than 100 m. 3 / m 2The high-polymer mesh belt possesses excellent resistance to wastewater corrosion and wear, and can withstand the continuous scouring of sand particles in activated sludge, making it resistant to rust. The belt exhibits good overall flexibility, resisting bending fatigue during elliptical rotation, preventing cracking and damage, and ensuring a long service life. Simultaneously, the relatively smooth surface of the polymer mesh belt prevents sludge and hair from adhering firmly. Combined with the high-pressure washing of the flushing system 5, adhering substances are more easily peeled off and removed, reducing the probability of belt clogging. The flocculent particles of activated sludge can smoothly pass through the mesh belt pores and return to the sludge return system 4, ensuring that the sludge required by the biological system is not lost. It can also effectively trap inorganic and fibrous impurities such as sand particles, hair, fibers, and solid grease larger than 500μm, achieving efficient interception of harmful suspended pollutants and preventing these impurities from continuing to circulate and accumulate in the biological treatment tank and MBR membrane tank 13, thus alleviating problems such as membrane fiber entanglement and clogging, and sand accumulation in the biological treatment tank from the source. The mesh belt operates in an elliptical rotation mode, achieving dynamic continuous filtration. The mesh belt rotates continuously, carrying trapped slag, sand, and hair to the discharge point for high-pressure washing. This allows for continuous operation, enabling filtration and slag removal simultaneously. Unlike static filter elements, this prevents localized accumulation of impurities on the filter surface, ensuring uninterrupted filtration without frequent shutdowns for media cleaning and enhancing the overall system's continuous operation capability. The hydraulic load on the equipment surface is no less than 100 m³. 3 / m 2 •h, high processing capacity per unit filtration area. Under the same sludge treatment scale, the effective filtration area of ​​the mesh belt can be reduced, the overall size of the equipment is smaller, and the equipment footprint is reduced, making it particularly suitable for the limited site space during the renovation of existing sewage treatment plants; under high throughput conditions, the hydraulic retention time of sludge is short, and the sludge stays in the equipment for a very short time, avoiding anaerobic deterioration and odor release caused by sludge retention, thus improving the site environment.

[0030] It should be noted that the hydraulic retention time of the mesh belt integrated slag and sand separation device 1 is less than 5 seconds, which is much shorter than that of traditional pretreatment processes. The processing capacity of a single unit can be varied over a wide range by adjusting the filtration precision, and can be adjusted according to the application scenario and sludge properties. Furthermore, multiple units can be connected in parallel to meet different processing scale requirements.

[0031] In some embodiments, the slag conveying device 2 adopts a shaftless spiral type or a belt conveyor type, with a drain outlet at the bottom, preferably the shaftless spiral type. Using a shaftless spiral eliminates the central shaft, effectively preventing hair and fibers from entangled in the shaft and causing jamming or blockage, and it is well-suited to entangled filamentous debris. Using a belt conveyor type results in low operating resistance, low energy consumption, and convenient disassembly and maintenance. Both types can be flexibly selected according to site space and slag properties to adapt to different project site conditions. The drain outlet at the bottom enables pre-dehydration during the slag conveying process. The slag and sand discharged from the mesh belt integrated slag and sand separation device 1 carries a large amount of free wastewater. During the transfer of the slag and sand within the conveying device, the free wastewater carried between the slag and sand can be discharged promptly from the bottom drain outlet, achieving pre-solid-liquid separation during the conveying stage. This reduces the moisture content of the slag and sand fed into the microporous pressing device 3, reduces the processing load of the subsequent microporous pressing device 3, and helps improve pressing and dewatering efficiency while reducing the energy consumption of the pressing equipment.

[0032] In some embodiments, the microporous pressing device 3 adopts a screw press or a pneumatic press, with a pressing precision of 200-500μm, preferably a screw press. When a screw press is selected, it relies on continuous screw pushing and squeezing, resulting in good feeding continuity, suitable for continuous feeding of slag, hair, and fibers, and stable operation, adapting to the continuous slag discharge process characteristics of this system. When a pneumatic press is selected, the pressing pressure is controllable, the squeezing force is large, and it has excellent dewatering effect for high-fiber, high-solids slag. Both types of equipment are suitable for this system, facilitating selection based on the slag composition and site layout conditions of the project, improving the system engineering adaptability. The pressing precision is set to 200-500μm, which can effectively intercept fine sand, short hair, and fibrous impurities. This precision can prevent most of the fine slag and fibers from passing through the screen and being lost with the filtrate, ensuring that the solid slag is fully trapped in the pressing chamber to complete the squeezing and dewatering, preventing fine particles from flowing back into the wastewater system with the filtrate and re-entering the biological treatment tank, ensuring that impurities are completely removed from the wastewater treatment system.

[0033] In some embodiments, the filter screen inside the microporous pressing device 3 is a wedge-shaped filter screen. The wedge-shaped filter screen has an inverted trapezoidal screen slit structure, with the inner side of the slit narrow and the outer side wide. The slits on the side of the filter screen where slag, hair, and fibers come into contact with the filter screen are smaller, while the slits on the side where the filtrate flows outward are larger. Hair and short fibers are less likely to get stuck and become embedded in the slits, which is suitable for the working conditions of this system where a large amount of hair and fibers are mixed in with the slag and sand, ensuring continuous operation of the pressing operation. The wedge-shaped filter screen is formed by welding metal wedge wires, which has good overall structural rigidity and can withstand the radial extrusion force generated during spiral or pneumatic pressing. It is not easily deformed under pressure, and the slits will not expand. It also has a longer service life due to continuous erosion and wear from slag and sand particles.

[0034] Example 2 This embodiment provides a wastewater treatment system, including raw water 8, a pretreatment tank 9, an anaerobic tank 10, an anoxic tank 11, an aerobic tank 12, an MBR membrane tank 13, and the wastewater treatment plant biochemical unit side-flow enhanced sludge removal system 101 in Embodiment 1. The raw water 8 enters the pretreatment tank 9, anaerobic tank 10, anoxic tank 11, aerobic tank 12, and MBR membrane tank 13 in sequence. The sludge in the aerobic tank 12 can be returned to the anoxic tank 11 or the anaerobic tank 10 through the first return pipe, and the sludge in the MBR membrane tank 13 can be returned to the aerobic tank 12 through the second return pipe. The sludge treated by the wastewater treatment plant biochemical unit side-flow enhanced sludge removal system 101 is the sludge in the first return pipe or the sludge in the second return pipe. The side-flow enhanced sludge and sand removal system 101 of the biological unit of the wastewater treatment plant is set on the sludge return side of the biological unit. It belongs to the bypass side-flow treatment and does not require modification of the raw water influent pretreatment section 8. It does not require modification of the original structures such as the pretreatment tank 9, anaerobic tank 10, anoxic tank 11, aerobic tank 12, and MBR membrane tank 13. The amount of civil engineering modification is small. It can be directly installed on the existing wastewater treatment plant to achieve uninterrupted transformation and upgrading, reducing transformation investment and construction cycle. When the sludge from the first return pipeline (from aerobic tank 12 to anoxic tank 11 / anaerobic tank 10) is selected as the treatment target, inert impurities such as slag and hair can be removed in advance before the sludge enters the anoxic and anaerobic units, reducing the deposition of inorganic particulate matter in the anaerobic-anoxic tank 11, avoiding sand accumulation in the tank and the occupation of effective tank volume, and protecting the anaerobic and anoxic environment. When the sludge from the second return pipeline (from MBR membrane tank 13 to aerobic tank 12) is selected as the treatment target, hair, fibers and fine sand can be removed before the sludge is returned to the aerobic tank 12, reducing the repeated entry of impurities into the MBR membrane tank 13 from the source, minimizing the risk of membrane fiber entanglement and blockage, protecting the membrane module, stabilizing the membrane water flux, and reducing the frequency of membrane cleaning.

[0035] 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. A side-flow enhanced slag and sand removal system for a biochemical unit in a wastewater treatment plant, characterized in that: The system includes a pumping device, a mesh belt integrated slag and sand separation device, a slag and sand conveying device, a microporous pressing device, and a sludge return system. Sludge from the biological treatment tank is conveyed to the sludge return system. The pumping device conveys the sludge containing slag and sand from the sludge return system to the mesh belt integrated slag and sand separation device. The mesh belt integrated slag and sand separation device is equipped with a rotating mesh belt. The slag outlet of the mesh belt integrated slag and sand separation device is connected to the slag and sand conveying device. The slag and sand conveying device transports the filtered slag and sand to the microporous pressing device, which presses and dewaters the filtered slag and sand. The sludge outlet of the mesh belt integrated slag and sand separation device is connected to the sludge return system, which can transport the filtered sludge back to the biological treatment tank.

2. The wastewater treatment plant biochemical unit side-flow enhanced slag and sand removal system according to claim 1, characterized in that: It also includes an automatic control system, which is electrically connected to the controllers of the pumping device, the mesh belt integrated slag and sand separation device, the slag and sand conveying device, the microporous pressing device, and the working elements in the sludge return system.

3. The wastewater treatment plant biochemical unit side-flow enhanced slag and sand removal system according to claim 1, characterized in that: The sludge return system includes a sludge return pump and a sludge return channel. The sludge return pump can transport the sludge in the biological treatment tank to the sludge return channel, and the pumping device can pump the sludge in the sludge return channel to the mesh belt integrated slag and sand separation device.

4. The wastewater treatment plant biochemical unit side-flow enhanced slag and sand removal system according to claim 2, characterized in that: It also includes a rinsing system, which includes a buffer water tank, a high-pressure rinsing pump, and an electrically controlled valve. The inlet of the high-pressure rinsing pump is connected to the buffer water tank. The high-pressure rinsing pump is provided with multiple outlets, and each outlet is equipped with an electrically controlled valve. The high-pressure rinsing pump is used to rinse the rotating mesh belt and the filter screen in the microporous pressing device. The controller of the high-pressure rinsing pump and the electrically controlled valve are both electrically connected to the automatic control system.

5. The wastewater treatment plant biochemical unit side-flow enhanced slag and sand removal system according to claim 3, characterized in that: The mesh belt integrated slag and sand separation device is located at a higher height than the sludge return channel, and the sludge filtered by the mesh belt integrated slag and sand separation device can return to the sludge return channel by its own weight.

6. The wastewater treatment plant biochemical unit side-flow enhanced slag and sand removal system according to claim 1, characterized in that: The mesh belt integrated slag and sand separation device uses a polymer mesh belt as the filter medium, with a filter pore size of 300-800μm, and rotates in an elliptical pattern with a surface hydraulic load of not less than 100m. 3 / m 2 ·h.

7. The wastewater treatment plant biochemical unit side-flow enhanced slag and sand removal system according to claim 1, characterized in that: The slag and sand conveying device adopts a shaftless spiral type or belt conveyor type, and a drainage outlet is provided at the bottom.

8. The wastewater treatment plant biochemical unit side-flow enhanced slag and sand removal system according to claim 1, characterized in that: The microporous pressing device adopts a screw press or a pneumatic press, with a pressing accuracy of 200-500μm.

9. The wastewater treatment plant biochemical unit side-flow enhanced slag and sand removal system according to claim 1, characterized in that: The filter screen inside the microporous pressing device is a wedge-shaped filter screen.

10. A wastewater treatment system, characterized in that: The system includes raw water, a pretreatment tank, an anaerobic tank, an anoxic tank, an aerobic tank, an MBR membrane tank, and a wastewater treatment plant biochemical unit side-flow enhanced sludge removal system as described in any one of claims 1-9. The raw water sequentially enters the pretreatment tank, the anaerobic tank, the anoxic tank, the aerobic tank, and the MBR membrane tank. The sludge from the aerobic tank can be returned to the anoxic tank or the anaerobic tank through a first return pipeline, and the sludge from the MBR membrane tank can be returned to the aerobic tank through a second return pipeline. The sludge treated by the wastewater treatment plant biochemical unit side-flow enhanced sludge removal system is the sludge in the first return pipeline or the sludge in the second return pipeline.

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