Activated sludge screening granulation process, device and use method

Abstract

Active sludge sieving granulation process, device and use method, relate to the technical field of sewage biochemical treatment, including screen component, screen component includes at least one sieve plate, sieve plate surface is provided with sieve hole, and the lower portion of sieve plate is provided with base;Aeration turbulent component, aeration turbulent component includes aeration pipe installed on the upper surface of base, aeration pipe surface is uniformly provided with aeration disc mounting seat, aeration disc mounting seat is provided with aeration disc above, and aeration pipe interface is installed at the end of aeration pipe;Local turbulent stirring component, local turbulent stirring device includes at least one stirring component, stirring component is arranged on any one side of sieve plate and above aeration disc;Multi-stage sieve hole is used, sieve plate is divided into upper, middle and lower three areas, aperture decreases in turn, can be accurately graded and intercepted according to particle size, aeration disc releases small bubbles to form turbulence, shear force is generated to destroy flocculent sludge structure, to promote microorganism to secrete EPS and accelerate particle densification, sludge volume index is reduced.

Description

Technical Field

[0001] This invention relates to the field of wastewater biochemical treatment technology, specifically to activated sludge screening and granulation process, apparatus, and usage method. Background Technology

[0002] In aerobic granular sludge processes, the particle size distribution of granular sludge directly affects its settling performance (characterized by sludge volume index, SVI) and biodegradation efficiency. Large-diameter particles (>200μm) have high density and low SVI, allowing them to settle quickly and maintain system stability; while small-diameter particles (<100μm) tend to disintegrate into flocs and are easily lost with the effluent, leading to uncontrolled sludge age and decreased system efficiency.

[0003] Currently, small particles are typically removed by shortening the settling time: in SBR (Sequencing Batch Reactor) or SBR-like reactors, the settling time is shortened to allow larger, denser sludge particles to settle preferentially, while smaller particles and flocculent sludge are carried away with the effluent. The main problem with this method may be that the settling time is too short, resulting in some medium-sized particles not settling completely, thus affecting the screening effect.

[0004] Furthermore, short-term settling may require strict operating conditions, such as sludge concentration and water flow velocity. Improper control of these parameters can lead to unstable screening efficiency. Increasing hydraulic shear force: This involves increasing hydraulic shear force through influent strategies to eliminate small particles that are not shear-resistant and promote the growth of shock-resistant granular sludge. The problem with this method may include excessive shear force potentially damaging the existing particle structure, causing particle disintegration and actually increasing the number of small particles.

[0005] A search revealed that utility model publication CN218931912U discloses a wastewater treatment activated sludge screening device, comprising: a first hydrocyclone with a first sludge inlet, a first heavy phase outlet, and a first light phase outlet, wherein the first sludge inlet is connected to the outlet of a residual sludge discharge system; and a second hydrocyclone with a second sludge inlet, a second heavy phase outlet, and a second light phase outlet, wherein the second sludge inlet is connected to the first heavy phase outlet, the second heavy phase outlet is a sludge discharge port for discharging residual sludge, and the second light phase outlet is a return port connected to a biological system. This device can perform continuous screening to ensure the proportion of organic sludge in the activated sludge; however, it does not screen for the particle size of granular sludge, leading to the easy loss of small granular sludge (i.e., flocculent sludge), resulting in uncontrolled sludge age and decreased system efficiency. Summary of the Invention

[0006] To address the problem that the lack of a screening device in the effluent of the biological treatment tank in the aerobic granular sludge process prevents further increase in sludge particle size, resulting in poor settling properties, especially in winter, and poor system treatment efficiency, this invention proposes an activated sludge screening and granulation process, device, and method of use to solve the above problems.

[0007] In traditional activated sludge treatment, large sludge particles, due to their high density and mass, settle quickly and typically settle at the bottom of the reactor; while small sludge particles or flocculent sludge, with their low density and loose structure, easily remain suspended in the upper layer or are lost with the effluent. However, the device of this invention, through the synergistic effect of multi-stage screening, aeration turbulence, and enhanced stirring, changes the separation mode that relies solely on natural sedimentation, achieving more efficient particle classification and retention.

[0008] An activated sludge screening and granulation device includes a screen component, the screen component including at least one screen plate, the surface of the screen plate having screen holes, and a base installed below the screen plate;

[0009] An aeration turbulence component includes an aeration pipe installed on the upper surface of the base, an aeration disc mounting seat uniformly fitted on the surface of the aeration pipe, an aeration disc installed above the aeration disc mounting seat, and an aeration pipe interface installed at the end of the aeration pipe.

[0010] A local turbulent mixing component, the local turbulent mixing device including at least one mixing component, the mixing component being disposed on any side of the sieve plate and located above the aeration disc.

[0011] Furthermore, setting up sieve plates significantly reduces the loss rate of small sludge particles, stabilizes sludge age, and improves system processing efficiency; however, flocculent sludge will accumulate on the surface of the sieve plates, causing blockage.

[0012] Furthermore, an aeration turbulence component is installed, which uses the micro-bubbles generated by the aeration disc to form an upward turbulence, applying shear force to the flocculent sludge, breaking down the loose floc structure of the sludge, and promoting particle compaction; at the same time, the turbulence promotes the uniform distribution of sludge, avoiding local accumulation.

[0013] Furthermore, by setting up local turbulent mixing components to form local eddies, the collision frequency between particles is increased, the granulation process is accelerated, and flocculent sludge is transformed into granular sludge, reducing the loss of small granular sludge.

[0014] Furthermore, the sieve plate includes an upper region, a middle region, and a lower region, and the sieve aperture decreases from top to bottom. For example, the sieve aperture on the surface of the upper region is 300-400 μm, the sieve aperture on the surface of the middle region is 150-200 μm, and the sieve aperture on the surface of the lower region is 50-100 μm.

[0015] Furthermore, the aperture of the sieve plate gradually decreases from top to bottom. The physical size limitation of the sieve aperture directly intercepts particles of the corresponding size. Large particles are intercepted by the larger aperture sieve in the upper zone and remain above the sieve plate; small particles need to pass through the smaller aperture sieve in the lower zone, but cannot pass through due to aperture limitation and are ultimately intercepted below the sieve plate.

[0016] Furthermore, through gradient screening, large particles are intercepted and further compacted in the upper zone, medium particles partially settle in the middle zone, and small particles are precisely intercepted by the screen holes in the lower zone, thus preventing flocculent sludge from being lost with the effluent.

[0017] Furthermore, the rising airflow generated by aeration exerts an upward buoyancy on large particles, but due to their large mass, the large particles are still trapped above the screen plate by the screen holes, while small particles are suspended in the water flow due to buoyancy and are eventually filtered by the screen holes in the lower zone.

[0018] Furthermore, the rising bubbles generated by the aeration disc create hydraulic shear force and turbulence, which, combined with the mixing action of the stirring blades, breaks up the flocculent sludge and promotes the compaction of large particles.

[0019] Furthermore, the sieve plate is inclined at 30 to 45 degrees to the horizontal plane, and the inclination direction is towards the direction of the sieve plate toward the aeration disc.

[0020] Furthermore, with the tilt direction facing the aeration zone, the sludge slides along the surface of the screen plate under the push of gravity and water flow; the water flow scouring effect reduces sludge adhesion on the screen hole surface, and the tilt angle prolongs the particle residence time, enhancing screening efficiency while reducing the probability of clogging.

[0021] Furthermore, when the screen plate is tilted, the sludge slides along the surface of the screen plate, the scouring effect of the water flow is enhanced, large particles accumulate in the area above the screen plate, while small particles are carried by the water flow to the lower screen holes.

[0022] Furthermore, the sieve holes are diamond-shaped or elongated, and the edges of the sieve holes are rounded.

[0023] Furthermore, the sieve holes in the lower region are provided with raised textures.

[0024] The raised texture increases the surface area and adsorption capacity, enhancing the ability to retain small particles; the rounded edges reduce the adhesion of fibrous impurities to the wall, reducing the risk of clogging.

[0025] Furthermore, it also includes a connector, which has grooves on both sides and an I-shaped cross-section. Limiting blocks are fixedly connected to both sides of the screen plate. When the screen plate is connected to the connector, the limiting blocks move linearly along the inner surface of the groove and extend into the base.

[0026] Furthermore, multiple screen plates are connected via connectors.

[0027] Furthermore, a hook is fixedly connected to the top surface of the sieve plate, and the surface of the sieve plate is covered with a composite coating.

[0028] Furthermore, the high abrasion resistance and hydrophobicity of the composite coating reduce biofilm adhesion, prevent corrosion, and reduce the frequency of manual cleaning.

[0029] Furthermore, the stirring component includes a stirring motor, the output end of which is connected to a stirring rod. The size of the stirring rod is the same as that of a single sieve plate, and stirring blades are uniformly fitted onto the surface of the stirring rod.

[0030] Furthermore, the leading edge of the stirring blade is arc-shaped, the trailing edge of the stirring blade is a tapered curved surface, the surface of the stirring blade is provided with a fish fin wavy texture, and the stirring blade is made of carbon fiber reinforced composite material.

[0031] Furthermore, the arc-shaped leading edge reduces resistance, while the tapered trailing edge accelerates water flow, forming local eddies, increasing the collision frequency between particles, and accelerating the granulation process.

[0032] Furthermore, the size of the stirring blades shown in the attached diagram is for illustrative purposes only; the actual dimensions need to be calculated based on the specific working efficiency.

[0033] Furthermore, when the biochemical tank is wide, stirring motors can be installed on both sides of the biochemical tank, with the stirring rods positioned opposite each other.

[0034] Furthermore, carbon fiber reinforced composite materials have low density and high strength, and their lightweight design reduces motor load and energy consumption during stirring; the fish fin wavy texture optimizes hydrodynamic properties, further improving energy efficiency.

[0035] Working principle:

[0036] The sieve plate is divided into three sections: upper, middle, and lower, with the aperture decreasing sequentially.

[0037] Upper zone: Large sludge particles are intercepted by using the physical restriction of the sieve openings to prevent them from passing through.

[0038] Central zone: Some medium-sized particles settle, while the remaining particles continue to migrate downwards.

[0039] Lower zone: Small particles are precisely trapped through the raised texture inside the sieve holes and the surface adsorption force. As the sludge flows from top to bottom, it is screened step by step to ensure that particles of different sizes are efficiently separated, and the extremely fine flocculent sludge that is not trapped is discharged with the effluent.

[0040] Aeration pipes release microbubbles with a diameter of 0.5–2 mm, forming an upward airflow and turbulence. The shear force generated when the bubbles rise disrupts the loose structure of flocculent sludge, prompting microorganisms to secrete extracellular polymeric substances (EPS). This uniformly disperses the sludge, preventing local accumulation and improving screening uniformity. In contrast, conventional aeration generally aims to increase the dissolved oxygen content in the water and promote the growth of aerobic organisms.

[0041] The mixing blades feature a fish fin-like wavy texture. This reduces water flow resistance, creates localized eddies, and increases the frequency of particle collisions. The curved leading edge and tapered trailing edge optimize fluid dynamics, accelerating particle bonding and compaction. The mixing is driven by a motor with adjustable speed, dynamically adjusting the mixing intensity based on sludge concentration to promote granulation.

[0042] EPS secretion and particle compaction

[0043] Biological function: The aeration shear force stimulates microorganisms to secrete EPS polysaccharides, proteins, etc., which act as "adhesives" to coat sludge particles.

[0044] Physical effect: The stirring eddy current causes repeated collisions between particles, and EPS gradually fills the pores to form a dense structure.

[0045] Multi-stage granulation process

[0046] Stage 1: Floc Breakup and Nucleus Formation. Aeration shear force breaks up flocculent sludge and forms initial particle nuclei.

[0047] Stage 2: Particle Growth and Stratification

[0048] Upper zone: Large particles are continuously subjected to aeration, shearing, and stirring above the sieve plate, resulting in increased EPS secretion and a gradual increase in particle size.

[0049] Lower zone: After small particles are trapped, they are further merged through hydraulic turbulence and collision to form medium-sized particles.

[0050] Stage 3: Densification and Stabilization. During the screening process, the particles repeatedly undergo shearing, collision and EPS encapsulation, eventually forming dense, highly settleable particles.

[0051] The method of using the activated sludge screening and granulation device includes the following steps:

[0052] Step 1: Connect the aeration system: Connect the aeration pipe to the external air source through the aeration pipe interface, and check whether the aeration pipe valve is in the closed state.

[0053] Step 2: Adjust the tilt angle of the sieve plate:

[0054] Vertical setting; the screen plate is vertically fixed to the base 11 through the sliding groove of the connector, ensuring that the limiting block 102 is fully embedded in the base.

[0055] Set the tilt angle to 30°~45°; loosen the fixing bolts of the connecting parts, adjust the tilt angle of the screen plate to the target value such as 40°, ensure that the screen plate is tilted towards the aeration disc, and tighten the bolts.

[0056] Step 3: Start the aeration system: Slowly open the aeration pipe valve, adjust the air pressure to 0.1-0.3 MPa, and observe whether tiny bubbles are evenly released on the surface of the aeration disc.

[0057] Step 4: Start the stirring components: Turn on the stirring motor and set the speed to 50-100 rpm. The stirring blades 4 will start to rotate. Make sure that the fin-like texture of the blades is consistent with the direction of the water flow.

[0058] Step 5, multi-stage screening: upper zone screening aperture 300-400μm: large sludge particles >200μm are trapped in the upper zone of the screen plate, while some medium particles 100-200μm flow downward with the water flow;

[0059] The sieve aperture in the middle zone is 150-200 μm: medium-sized particles partially settle in the middle zone, while the remaining particles continue to migrate downwards.

[0060] The lower zone has a sieve aperture of 50–100 μm: small particles <100 μm are retained by the lower zone sieve aperture 3, while flocculent sludge passes through the sieve aperture and is discharged with the effluent.

[0061] Step 6, Granular sludge recovery: The granular sludge after screening is collected through the sludge discharge pipe. The sludge discharge valve is opened periodically to discharge the dense particles, and the sludge discharge frequency is controlled to be once every 2 hours.

[0062] Step 7, Aeration intensity adjustment: Adjust the air pressure through the aeration pipe valve according to the screening effect;

[0063] If too many small particles remain, increase the air pressure to 0.3 MPa to enhance the hydraulic shear force;

[0064] If the particle breakage rate is too high, reduce the air pressure to 0.1 MPa to reduce the turbulence intensity.

[0065] Step 8, Screen Hole Cleaning: After each shift, turn off the mud inlet and aeration system, and use a high-pressure water gun to rinse the screen holes from the bottom of the screen plate in reverse, focusing on cleaning the raised textured areas inside the screen holes in the lower zone.

[0066] Compared with the prior art, the present invention has the following beneficial effects:

[0067] 1. Precise grading and screening to reduce the loss of small sludge particles: The device adopts a multi-stage screen design, with the screen plate divided into upper, middle, and lower zones, and the aperture decreasing sequentially. This allows for precise grading and retention based on particle size, or the selection of different aperture sizes according to the treatment stage. Large particles are intercepted and compacted in the upper zone, medium-sized particles partially settle in the middle zone, and small particles are retained in the lower zone. Furthermore, the raised texture of the screen apertures enhances adsorption. This significantly reduces the loss rate of small particles, stabilizes the sludge age, and improves system stability. Simultaneously, the optimized screen aperture structure reduces the risk of wall adhesion and clogging, protecting the integrity of the particles.

[0068] 2. Promotes particle compaction and improves settling performance: The aeration disc releases microbubbles to create turbulence, generating shear force that breaks down the flocculent sludge structure. This prompts microorganisms to secrete EPS, accelerating particle compaction, reducing the sludge volume index, and increasing settling velocity. The uniquely designed carbon fiber stirring blades reduce water flow resistance, create vortices to promote particle collision and fusion, optimize fluid dynamics, shorten the granulation cycle, and improve the mechanical strength of the particles.

[0069] 3. Anti-clogging design, reducing maintenance costs: The inclined screen plate allows sludge to slide along the surface under the action of gravity and water flow. The water flow washes away sludge adhesion, reducing the frequency of clogging and extending maintenance intervals. The polyurethane-ceramic composite coating is wear-resistant, corrosion-resistant, and hydrophobic, reducing biofilm adhesion, preventing screen hole corrosion, extending the service life of the screen plate, and reducing maintenance costs.

[0070] 4. Energy Saving and Operational Flexibility: The carbon fiber agitator blades have low density and high strength, reducing motor load and energy consumption. Dynamic aeration adjustment controls air pressure as needed, avoiding excessive energy consumption. The adjustable screen angle and agitation speed can adapt to different sludge concentrations and treatment scales, resulting in overall reduced energy consumption and strong applicability.

[0071] 5. Process stability and shock resistance: The large sludge particles after screening have a dense structure and strong resistance to hydraulic shock. The system's tolerance to fluctuations in influent flow rate and pollutant concentration is improved, and the suspended solids in the effluent are stable. By monitoring the particle size distribution and dynamically adjusting parameters, screening conditions are optimized in real time to ensure long-term operational stability. Attached Figure Description

[0072] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0073] Figure 1 A schematic diagram of the installation of an activated sludge screening and granulation device;

[0074] Figure 2Diagram a shows the structure of an activated sludge screening and granulation device;

[0075] Figure 3 Figure b shows the structure of the activated sludge screening and granulation device;

[0076] Figure 4 Figure c shows the structure of an activated sludge screening and granulation device.

[0077] Figure 5 d is a structural diagram of an activated sludge screening and granulation device;

[0078] Figure 6 Top view of the activated sludge screening and granulation device;

[0079] Figure 7 Side view showing the sieve plate arranged at an angle.

[0080] In the picture:

[0081] 1. Sieve plate; 101. Hook and ring; 102. Limiting block;

[0082] 2. Connecting parts;

[0083] 3. Sieve aperture;

[0084] 4. Agitator blades;

[0085] 5. Aeration pipe;

[0086] 6. Aeration disc mounting base;

[0087] 7. Aeration disc;

[0088] 8. Stirring rod;

[0089] 9. Agitator motor;

[0090] 10. Pool wall;

[0091] 11. Base;

[0092] 12. Water baffle;

[0093] 13. Aeration pipe interface;

[0094] 14. Reaction tank;

[0095] 15. Sludge discharge pipe;

[0096] 16. Sludge discharge valve;

[0097] 17. Aeration pipe valve. Detailed Implementation

[0098] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0099] The application principle of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0100] Example 1

[0101] like Figure 1-6 As shown, the activated sludge screening and granulation device includes a screen component, which includes at least one screen plate 1. The surface of the screen plate 1 is provided with screen holes 3. A base 11 is installed below the screen plate 1. The base 11 is installed at the outlet of the reaction tank 14 and is submerged below the water surface.

[0102] The aeration turbulence component includes an aeration pipe 5 installed on the upper surface of the base 11, an aeration disc mounting seat 6 uniformly sleeved on the surface of the aeration pipe 5, an aeration disc 7 installed above the aeration disc mounting seat 6, and an aeration pipe interface 13 installed at the end of the aeration pipe 5.

[0103] The local turbulent flow mixing device includes at least one mixing component, which is disposed on any side of the screen plate 1 and located above the aeration disc 7.

[0104] Setting up screen plate 1 significantly reduces the loss rate of small sludge particles, stabilizes sludge age, and improves system processing efficiency. However, flocculent sludge will accumulate on the surface of screen plate 1, causing blockage.

[0105] The aeration turbulence component is set up, and the micro bubbles generated by the aeration disc 7 form an upward turbulence, which applies shear force to the flocculent sludge, destroys the loose floc structure of the flocculent sludge, and promotes the compaction of particles; at the same time, the turbulence promotes the uniform distribution of sludge and avoids local accumulation.

[0106] The system incorporates localized turbulent mixing components to create localized eddies, thereby increasing the collision frequency between particles, accelerating the granulation process, transforming flocculent sludge into granular sludge, and reducing the loss of small sludge particles.

[0107] Example 2

[0108] like Figure 1-7 As shown, based on Example 1, the activated sludge screening and granulation device includes a sieve plate 1 comprising an upper zone, a middle zone, and a lower zone. The aperture of the sieve holes 3 decreases from top to bottom, for example, the aperture of the sieve holes 3 on the surface of the upper zone is 300-400 μm, the aperture of the sieve holes 3 on the surface of the middle zone is 150-200 μm, and the aperture of the sieve holes 3 on the surface of the lower zone is 50-100 μm.

[0109] The aperture of the sieve plate 1 decreases gradually from top to bottom. The physical size limitation of the sieve aperture directly intercepts particles of the corresponding size. Large particles >200μm are intercepted by the larger aperture sieve aperture of 300-400μm in the upper zone and remain above the sieve plate. Small particles <100μm need to pass through the smaller aperture sieve aperture of 50-100μm in the lower zone, but cannot pass through due to the aperture limitation and are ultimately intercepted below the sieve plate.

[0110] Through gradient screening, large particles are intercepted in the upper zone and further compacted, medium particles partially settle in the middle zone, and small particles are precisely intercepted by the screen holes in the lower zone, thus preventing flocculent sludge from being lost with the effluent.

[0111] The rising airflow generated by aeration exerts an upward buoyancy on large particles, but due to their large mass, the large particles are still trapped above the screen plate by the screen holes, while small particles are suspended in the water flow due to buoyancy and are eventually filtered by the screen holes in the lower zone.

[0112] The rising bubbles generated by the aeration disc 7 create hydraulic shear force and turbulence, which, combined with the mixing action of the stirring blades 4, breaks up the flocculent sludge and promotes the compaction of large particles.

[0113] The sieve plate 1 is inclined at 30 to 45 degrees to the horizontal plane, and the inclination direction is towards the sieve plate 1 and towards the aeration disc 7.

[0114] The sludge is tilted towards the aeration zone, and under the influence of gravity and water flow, it slides along the surface of the screen plate. The water flow reduces the adhesion of sludge to the screen hole surface, and the tilt angle extends the particle residence time, thereby enhancing screening efficiency and reducing the probability of clogging.

[0115] When the screen plate 1 is tilted, the sludge slides along the surface of the screen plate 1, the scouring effect of the water flow is enhanced, large particles accumulate in the area above the screen plate 1, and small particles are carried by the water flow to the lower screen holes 3.

[0116] The sieve hole 3 is diamond-shaped or elongated, and the edges of the sieve hole 3 are rounded.

[0117] The sieve hole 3 located in the lower region has raised textures inside.

[0118] The raised texture increases the surface area and adsorption capacity, enhancing the ability to retain small particles; the rounded edges reduce the adhesion of fibrous impurities to the wall, reducing the risk of clogging.

[0119] It also includes a connector 2, which has grooves on both sides and has an I-shaped cross section. Limiting blocks 102 are fixedly connected to both sides of the screen plate 1. When the screen plate 1 is connected to the connector 2, the limiting blocks 102 move linearly along the inner surface of the groove and extend into the base.

[0120] Multiple screen plates 1 are connected via connector 2.

[0121] The top surface of the sieve plate 1 is fixedly connected with a hook ring 101, and the surface of the sieve plate 1 is covered with a composite coating.

[0122] The high abrasion resistance and hydrophobicity of the composite coating reduce biofilm adhesion, prevent corrosion, and reduce the frequency of manual cleaning.

[0123] The stirring component includes a stirring motor 9, the output end of which is connected to a stirring rod 8. The size of the stirring rod 8 is the same as that of a single sieve plate 1, and stirring blades 4 are uniformly fitted onto the surface of the stirring rod 8.

[0124] The leading edge of the stirring blade 4 is arc-shaped, the trailing edge of the stirring blade 4 is a tapered curved surface, the surface of the stirring blade 4 is provided with a fish fin wavy texture, and the stirring blade 4 is made of carbon fiber reinforced composite material.

[0125] The curved leading edge reduces resistance, while the tapered trailing edge accelerates water flow, forming local eddies that increase the frequency of particle collisions and speed up the granulation process.

[0126] Carbon fiber reinforced composite materials have low density and high strength. Their lightweight design reduces motor load and minimizes stirring energy consumption. The fish fin-like texture optimizes hydrodynamic properties and further improves energy efficiency.

[0127] Example 3

[0128] like Figure 1-7 As shown: Activated sludge screening and granulation device, including screen components, the screen components including at least one screen plate 1, the surface of the screen plate 1 is provided with screen holes 3, and a base 11 is installed below the screen plate 1;

[0129] The aeration turbulence component includes an aeration pipe 5 installed on the upper surface of the base 11, an aeration disc mounting seat 6 uniformly sleeved on the surface of the aeration pipe 5, an aeration disc 7 installed above the aeration disc mounting seat 6, and an aeration pipe interface 13 installed at the end of the aeration pipe 5.

[0130] The local turbulent flow mixing device includes at least one mixing component, which is disposed on any side of the screen plate 1 and located above the aeration disc 7.

[0131] Setting up sieve plate 1 significantly reduces the loss rate of small sludge particles with a particle size of <100μm, stabilizes sludge age, and improves system processing efficiency. However, flocculent sludge will accumulate on the surface of sieve plate 1, causing blockage.

[0132] The aeration turbulence component is set up, and the micro bubbles generated by the aeration disc 7 form an upward turbulence, which applies shear force to the flocculent sludge, destroys the loose floc structure of the flocculent sludge, and promotes the compaction of particles; at the same time, the turbulence promotes the uniform distribution of sludge and avoids local accumulation.

[0133] The system incorporates localized turbulent mixing components to create localized eddies, thereby increasing the collision frequency between particles, accelerating the granulation process, transforming flocculent sludge into granular sludge, and reducing the loss of small sludge particles.

[0134] The sieve plate 1 includes an upper region, a middle region, and a lower region. The aperture 3 of the sieve holes decreases from top to bottom. For example, the aperture 3 of the sieve holes on the surface of the upper region is 300-400 μm, the aperture 3 of the sieve holes on the surface of the middle region is 150-200 μm, and the aperture 3 of the sieve holes on the surface of the lower region is 50-100 μm.

[0135] The aperture of the sieve plate 1 decreases gradually from top to bottom. The physical size limitation of the sieve aperture directly intercepts particles of the corresponding size. Large particles >200μm are intercepted by the larger aperture sieve aperture of 300-400μm in the upper zone and remain above the sieve plate. Small particles <100μm need to pass through the smaller aperture sieve aperture of 50-100μm in the lower zone, but cannot pass through due to the aperture limitation and are ultimately intercepted below the sieve plate.

[0136] Through gradient screening, large particles are intercepted in the upper zone and further compacted, medium particles partially settle in the middle zone, and small particles are precisely intercepted by the screen holes in the lower zone, thus preventing flocculent sludge from being lost with the effluent.

[0137] The rising airflow generated by aeration exerts an upward buoyancy on large particles, but due to their large mass, the large particles are still trapped above the screen plate by the screen holes, while small particles are suspended in the water flow due to buoyancy and are eventually filtered by the screen holes in the lower zone.

[0138] The rising bubbles generated by the aeration disc 7 create hydraulic shear force and turbulence, which, combined with the mixing action of the stirring blades 4, breaks up the flocculent sludge and promotes the compaction of large particles.

[0139] The sieve plate 1 is inclined at 30 to 45 degrees to the horizontal plane, and the inclination direction is towards the sieve plate 1 and towards the aeration disc 7.

[0140] The sludge is tilted towards the aeration zone, and under the influence of gravity and water flow, it slides along the surface of the screen plate. The water flow reduces the adhesion of sludge to the screen hole surface, and the tilt angle extends the particle residence time, thereby enhancing screening efficiency and reducing the probability of clogging.

[0141] When the screen plate 1 is tilted, the sludge slides along the surface of the screen plate 1, the scouring effect of the water flow is enhanced, large particles accumulate in the area above the screen plate 1, and small particles are carried by the water flow to the lower screen holes 3.

[0142] The sieve hole 3 is diamond-shaped or elongated, and the edges of the sieve hole 3 are rounded.

[0143] The sieve hole 3 located in the lower region has raised textures inside.

[0144] The raised texture increases the surface area and adsorption capacity, enhancing the ability to retain small particles; the rounded edges reduce the adhesion of fibrous impurities to the wall, reducing the risk of clogging.

[0145] It also includes a connector 2, which has grooves on both sides and has an I-shaped cross section. Limiting blocks 102 are fixedly connected to both sides of the screen plate 1. When the screen plate 1 is connected to the connector 2, the limiting blocks 102 move linearly along the inner surface of the groove and extend into the base.

[0146] Multiple screen plates 1 are connected via connector 2.

[0147] The top surface of the sieve plate 1 is fixedly connected with a hook ring 101, and the surface of the sieve plate 1 is covered with a composite coating.

[0148] The high abrasion resistance and hydrophobicity of the composite coating reduce biofilm adhesion, prevent corrosion, and reduce the frequency of manual cleaning.

[0149] The stirring component includes a stirring motor 9, the output end of which is connected to a stirring rod 8. The size of the stirring rod 8 is the same as that of a single sieve plate 1, and stirring blades 4 are uniformly fitted onto the surface of the stirring rod 8.

[0150] The leading edge of the stirring blade 4 is arc-shaped, the trailing edge of the stirring blade 4 is a tapered curved surface, the surface of the stirring blade 4 is provided with a fish fin wavy texture, and the stirring blade 4 is made of carbon fiber reinforced composite material.

[0151] The curved leading edge reduces resistance, while the tapered trailing edge accelerates water flow, forming local eddies that increase the frequency of particle collisions and speed up the granulation process.

[0152] Carbon fiber reinforced composite materials have low density and high strength. Their lightweight design reduces motor load and minimizes stirring energy consumption. The fish fin-like texture optimizes hydrodynamic properties and further improves energy efficiency.

[0153] Example 4

[0154] The method of using the activated sludge screening and granulation device includes the following steps:

[0155] Step 1: Connect the aeration system: Connect the aeration pipe 5 to the external air source through the aeration pipe interface 13, check whether the aeration pipe valve 17 is in the closed state, fix the stirring motor 9 on the outside of the pool wall 10, and set the baffle plate 12 at the water inlet of the outlet weir.

[0156] Step 2: Adjust the tilt angle of sieve plate 1:

[0157] Vertical setting; the screen plate 1 is vertically fixed to the base 11 through the sliding groove of the connector 2, ensuring that the limiting block 102 is fully embedded in the base.

[0158] Set the tilt angle to 30-45°; loosen the fixing bolts of connector 2, adjust the tilt angle of the screen plate to the target value such as 40°, ensure that the screen plate is tilted towards the aeration disc 7, and tighten the bolts.

[0159] Step 3: Start the aeration system: Slowly open the aeration pipe valve 17, adjust the air pressure to 0.1-0.3 MPa, and observe whether the surface of the aeration disc 7 releases tiny bubbles evenly.

[0160] Step 4: Start the stirring components: Turn on the stirring motor 9 and set the speed to 50-100 rpm. The stirring blades 4 will start to rotate. Make sure that the fin-like texture of the blades is consistent with the direction of the water flow.

[0161] Step 5, multi-stage screening: upper zone screening aperture 300-400μm: large sludge particles >200μm are trapped in the upper zone of the screen plate, while some medium particles 100-200μm flow downward with the water flow;

[0162] The sieve aperture in the middle zone is 150-200 μm: medium-sized particles partially settle in the middle zone, while the remaining particles continue to migrate downwards.

[0163] The lower zone has a sieve aperture of 50–100 μm: small particles <100 μm are retained by the lower zone sieve aperture 3, while flocculent sludge passes through the sieve aperture and is discharged with the effluent.

[0164] Step 6, Granular sludge recovery: The granular sludge after screening is collected through the sludge discharge pipe 15, and the dense particles are discharged periodically by opening the sludge discharge valve 16, controlling the sludge discharge frequency to once every 2 hours.

[0165] Step 7, Aeration intensity adjustment: Adjust the air pressure through aeration pipe valve 17 according to the screening effect;

[0166] If too many small particles remain, increase the air pressure to 0.3 MPa to enhance the hydraulic shear force;

[0167] If the particle breakage rate is too high, reduce the air pressure to 0.1 MPa to reduce the turbulence intensity.

[0168] Step 8, Screen hole cleaning: After each shift, turn off the mud inlet and aeration system, and use a high-pressure water gun to rinse the screen holes 3 from the bottom of the screen plate 1 in reverse, focusing on cleaning the raised texture area inside the screen holes in the lower area.

Claims

1. An activated sludge screening and granulation device, characterized in that: include: A screen component, the screen component including at least one screen plate (1), the surface of the screen plate (1) is provided with screen holes (3), and a base (11) is installed below the screen plate (1). It also includes: an aeration turbulence component, which includes an aeration pipe (5) installed on the upper surface of the base (11), an aeration disc mounting seat (6) uniformly sleeved on the surface of the aeration pipe (5), and an aeration disc (7) installed above the aeration disc mounting seat (6). It also includes: a local turbulent mixing component, which includes at least one mixing component, which is disposed on any side of the sieve plate (1) and located above the aeration disc (7); The sieve plate (1) includes an upper zone, a middle zone and a lower zone. The aperture of the sieve holes (3) decreases from top to bottom. The sieve plate (1) is inclined at 30 to 45 degrees to the horizontal plane, and the inclination direction is towards the sieve plate (1) and closer to the aeration disc (7).

2. The activated sludge screening and granulation device according to claim 1, characterized in that: The shape of the sieve holes (3) in each zone can be independently selected as rhomboid holes or elongated holes, and the edges of the sieve holes (3) are rounded.

3. The activated sludge screening and granulation device according to claim 2, characterized in that: The sieve holes (3) in the lower zone have raised textures inside.

4. The activated sludge screening and granulation device according to claim 1, characterized in that: It also includes a connector (2), which has grooves on both sides. The connector (2) has an I-shaped cross section. Limiting blocks (102) are fixedly connected to both sides of the sieve plate (1). When the sieve plate (1) is connected to the connector (2), the limiting blocks (102) move linearly along the inner surface of the groove and extend into the base.

5. The activated sludge screening and granulation device according to claim 4, characterized in that: The top surface of the sieve plate (1) is fixedly connected with a hook (101), and the surface of the sieve plate (1) is covered with a composite coating.

6. The activated sludge screening and granulation device according to claim 1, characterized in that: The stirring component includes a stirring motor (9), the output end of which is connected to a stirring rod (8). The size of the stirring rod (8) is the same as that of a single sieve plate (1), and stirring blades (4) are uniformly fitted on the surface of the stirring rod (8).

7. The activated sludge screening and granulation device according to claim 6, characterized in that: The front edge of the stirring blade (4) is arc-shaped, the rear edge of the stirring blade (4) is a tapered curved surface, the surface of the stirring blade (4) is provided with a fish fin wavy texture, and the material of the stirring blade (4) is carbon fiber reinforced composite material.

8. The activated sludge screening and granulation device according to any one of claims 1 to 7, characterized in that, Includes the following steps: X1. Activated sludge screening and treatment: Activated sludge particles of different sizes enter the outlet of the biological treatment tank with the water flow. The water flows through the barrier, which intercepts large sludge particles and some flocculent sludge. Some flocculent sludge flows out with the water flow. X2. Flocculent sludge dispersion treatment: The flocculent sludge is broken down by the impact of microbubbles generated by the aeration turbulence component, forming micro sludge that is fully mixed in the water; X3. Sludge granulation treatment: The broken, tiny sludge particles are suspended in water. The water flow is disturbed by a local turbulent mixing component, causing the tiny sludge particles suspended in the water to collide and combine with each other to form large sludge particles.

9. The method of using the activated sludge screening and granulation apparatus according to any one of claims 1 to 7, characterized in that, Includes the following steps: Step 1: Connect the aeration system: Connect the aeration pipe (5) to the external air source through the aeration pipe interface (13), check whether the aeration pipe valve (17) is closed, fix the stirring motor (9) on the outside of the pool wall (10), and set a baffle plate (12) at the water inlet of the outlet weir. Step 2: Adjust the tilt angle of the sieve plate (1): Vertical setting; the sieve plate (1) is vertically fixed to the base (11) through the groove of the connector (2), ensuring that the limiting block (102) is fully embedded in the base; Set the tilt angle to 30°~45°; loosen the fixing bolts of the connector (2), adjust the tilt angle of the screen plate to the target value such as 40°, ensure that the screen plate is tilted towards the aeration disc (7), and tighten the bolts; Step 3: Start the aeration system: Slowly open the aeration pipe valve (17), adjust the air pressure to 0.1~0.3MPa, and observe whether the surface of the aeration disc (7) releases tiny bubbles evenly. Step 4: Start the stirring components: Turn on the stirring motor (9), set the speed to 50-100 rpm, and the stirring blades (4) will start to rotate. Make sure that the fin-like texture of the blades is consistent with the direction of the water flow. Step 5, multi-stage screening: When large sludge particles flow with the water flow, they pass through the upper zone and are trapped in the upper zone of the screen plate (1). Some medium and small sludge particles flow downward with the water flow. When medium-sized particles settle in the middle zone, they are intercepted as they pass through the screening aperture of the middle zone, and the remaining particles continue to migrate downwards. When small particles reach the lower zone screen holes, they are intercepted by the lower zone screen holes (3), while some of the unintercepted flocculent sludge is discharged with the effluent through the screen holes (3). Step 6, Granular sludge recovery: The granular sludge after screening is collected through the sludge discharge pipe (15), and the dense particles are discharged by opening the sludge discharge valve (16) periodically, and the sludge discharge frequency is controlled to be once every 2 hours. Step 7, Aeration intensity adjustment: Adjust the air pressure through the aeration pipe valve (17) according to the screening effect; If too many small particles remain, increase the air pressure to 0.3 MPa to enhance the hydraulic shear force; If the particle breakage rate is too high, reduce the air pressure to 0.1 MPa to reduce the turbulence intensity; Step 8, Screen hole cleaning: Turn off the mud inlet and aeration system, and use a high-pressure water gun to backwash the screen holes (3) from the bottom of the screen plate (1), focusing on cleaning the raised texture area inside the screen holes in the lower area.

Images