System fine sand secondary recovery and sludge concentration control device, control method thereof and sewage treatment system

Abstract

The invention provides a system fine sand secondary recovery and sludge concentration control device, a control method thereof and a sewage treatment system. The fine sand secondary recovery and sludge concentration control device of the system comprises a sludge inlet buffer area; the rotational flow sand collecting area is communicated with the inlet mud buffer area through a mud inlet pipeline to form a cylindrical rotational flow space, the mud inlet pipeline extends in the tangential direction of the rotational flow space, a fine sand settling area is formed at the bottom of the rotational flow space and communicated to the outside through a recycled sand outlet, and a sand collecting area outlet is formed in the top of the rotational flow space; the scum collecting area is communicated with an outlet of the sand collecting area and is communicated to the outside through a scum discharging opening; the sludge secondary settling area is communicated with the scum collecting area; and the sludge secondary settling zone is communicated with the overflow sludge discharge zone through an overflow structure. The sand-adding high-efficiency sedimentation tank can be used for treating discharge of a sewage treatment system, recycling of fine sand is realized, and discharge control of sludge concentration is realized, so that the problems that a traditional sand-adding high-efficiency sedimentation tank is too high in sand loss and too high in water content of residual discharged sludge are solved.

Description

Technical Field

[0001] The invention relates to the technical field of sewage treatment, and in particular to a system fine sand secondary recovery and sludge concentration control device and a control method thereof, and a sewage treatment system. Background Art

[0002] The sand-added high-efficiency sedimentation tank is based on the coagulation, flocculation and sedimentation technology of the high-speed clarification tank. Sand media is added through the coagulation and flocculation stage to work together with polymer flocculants (PAC) and polymer coagulant aids (PAM) to increase the probability of flocculation particle collision and strengthen the reaction effect of coagulation and flocculation, making it easier to capture destabilized suspended matter in the water, forming a larger density of alum flowers, and achieving efficient mud and water separation and sedimentation.

[0003] As attached Figure 1 As shown, the raw water to be purified passes through the coagulation contact tank, coagulation sand tank, flocculation tank, and inclined plate sedimentation tank of the sand-added high-efficiency sedimentation tank in turn to obtain purified water. The traditional sand and sludge mixture at the bottom of the inclined plate sedimentation tank is pumped into the hydrocyclone through a circulation pump, and most of the fine sand enters the coagulation sand tank from the lower sediment return pipe. The other sludge goes to the residual sludge tank from the upper pipe and is discharged into the concentration tank. The stable sand medium hydrocyclone recovery device is the guarantee for achieving faster, more efficient and stable TP and SS treatment.

[0004] In order to maintain a stable concentration of sludge and fine sand in the sedimentation tank, the circulating pump must be turned on continuously, and the hydrocyclone also works continuously for 24 hours. The sludge discharge volume of the traditional hydrocyclone is determined by the flow rate of the circulating pump. In actual operation, it is impossible to accurately control the daily sludge discharge volume by relying solely on the frequency conversion control flow of the circulating pump. At the same time, the sludge concentration in the sedimentation tank cannot be controlled. If the circulating pump is turned on too high, the moisture content of the remaining sludge is too high. If the circulating pump is turned on too low, the speed in the hydrocyclone is low, the separation effect of the silt and sand is not good, and a lot of sand enters the remaining sludge, causing great waste. The difficulty in controlling the return ratio during operation control is a major difficulty in sand-added high-efficiency sedimentation tanks.

[0005] At the same time, it was found that even in the steady state of the system, the micro-sand content in the upper sludge is still relatively large, the sand loss is large, and the daily micro-sand replenishment must reach 4~6mg / L (water intake), and the operating cost of adding sand is high. At the same time, the sludge water content is high, about 99.4~99.8%, which causes a large water impact on the subsequent sludge disposal and low desludging efficiency.

[0006] At the same time, the discharge of a large amount of fine sand will cause serious wear and tear on the subsequent sludge deep treatment system equipment of the sewage treatment plant, making the equipment prone to damage. Summary of the invention

[0007] The present invention provides a system fine sand secondary recovery and sludge concentration control device and a control method thereof and a sewage treatment system, which are used to solve the defects in the prior art and achieve the following technical effects: the discharge from the sewage treatment system can be treated. On the one hand, the fine sand in the discharge can be recycled and utilized, and on the other hand, the discharge concentration of the sludge can be controlled, thereby solving the problems of excessive sand loss in the traditional sand-added high-efficiency sedimentation tank and excessively high water content of the residual sludge.

[0008] The system fine sand secondary recovery and sludge concentration control device according to the first embodiment of the present invention comprises: A mud inlet buffer area having a mud inlet, wherein the mud inlet is connected to a discharge outlet of the sewage treatment system for receiving discharge from the system; A cyclone sand collecting area is connected with the sludge inlet buffer area through a sludge inlet pipe, and a cylindrical cyclone space is formed inside the cyclone sand collecting area. The sludge inlet pipe extends along the tangential direction of the cyclone space so that the discharge forms a cyclone, and a fine sand sedimentation area is formed at the bottom of the cyclone space, and the fine sand sedimentation area is connected to the outside through a recovered sand outlet; a sand collecting area outlet is formed at the top of the cyclone space, wherein, under the action of the cyclone, the fine sand in the discharge falls into the fine sand sedimentation area, and the scum and sludge in the discharge are discharged through the sand collecting area outlet; A scum collecting area is connected to the sand collecting area outlet of the cyclone sand collecting area, and the scum collecting area is connected to the outside through a scum discharge port; A sludge secondary sedimentation zone is connected to the sludge collection zone through a sludge through hole, and the sludge in the sludge collection zone enters the sludge secondary sedimentation zone through the sludge through hole; The overflow mud discharge area is provided with an overflow structure on the top of the overflow mud discharge area, the sludge secondary sedimentation area is connected with the overflow mud discharge area through the overflow structure, and the overflow mud discharge area is connected to the outside through the sludge discharge port.

[0009] According to one embodiment of the present invention, a first regulating valve with adjustable opening is provided at the recovered sand outlet, and a second regulating valve with adjustable opening is provided at the sludge discharge outlet.

[0010] According to one embodiment of the present invention, the cyclone sand collecting area further comprises a flow guiding center cylinder, the flow guiding center cylinder extends along the central axis of the cyclone space and the central axes of the two coincide with each other; In the height direction of the cyclone space, the flow guiding center cylinder is respectively arranged opposite to the mud inlet pipeline and the sand collecting area outlet.

[0011] According to one embodiment of the present invention, the cyclone sand collecting area further comprises a guide reflector plate, the guide reflector plate is truncated cone-shaped and its central axis coincides with the central axis of the guide central tube, and the end of the guide reflector plate with a smaller diameter is connected to the bottom end of the guide central tube; In the height direction of the cyclone space, the guide reflection plate is located between the mud inlet pipe and the fine sand precipitation area.

[0012] According to one embodiment of the present invention, a fine sand discharge area is provided outside the fine sand sedimentation area, the fine sand discharge area is connected to the fine sand sedimentation area and the sludge secondary sedimentation area respectively, and the recovered sand outlet is provided on the side wall of the fine sand discharge area.

[0013] According to one embodiment of the present invention, in the direction from the fine sand sedimentation area to the fine sand discharge area, the bottom of the system fine sand secondary recovery and sludge concentration control device is provided with a first sand guide slope with a gradually decreasing height; And / or, in the direction from the sludge secondary sedimentation zone to the fine sand discharge zone, a second sand guiding slope with a gradually decreasing height is provided at the bottom of the system fine sand secondary recovery and sludge concentration control device.

[0014] According to one embodiment of the present invention, the sludge passage hole is provided at the bottom of the scum collection area; And / or, the sludge inlet buffer area is connected to the sludge secondary sedimentation area through an overflow hole arranged on the top thereof.

[0015] According to one embodiment of the present invention, the overflow structure is an overflow weir arranged at the top of the overflow mud discharge area, and the overflow weir is sawtooth-shaped and extends along the top wall of the overflow mud discharge area.

[0016] According to the second embodiment of the present invention, a control method of the system fine sand secondary recovery and sludge concentration control device based on the first embodiment of the present invention comprises: Obtain the target concentration range of sludge discharged from the system; According to the target concentration range, the openings of the first regulating valve and the second regulating valve are controlled and adjusted.

[0017] A sewage treatment system according to a third aspect of the present invention comprises: The system fine sand secondary recovery and sludge concentration control device as described in the embodiment of the first aspect of the present invention; The coagulation contact tank, the coagulation sand adding tank, the flocculation tank and the inclined plate sedimentation tank are connected in sequence. The inclined plate sedimentation tank is connected to the hydrocyclone through the purified water outlet. The sediment return pipe of the hydrocyclone is connected to the coagulation sand adding tank, and the residual sludge discharge pipe of the hydrocyclone is connected to the mud inlet of the system fine sand secondary recovery and sludge concentration control device, and the recovered sand outlet of the system fine sand secondary recovery and sludge concentration control device is also connected to the coagulation sand adding tank.

[0018] The present invention provides a system fine sand secondary recovery and sludge concentration control device, which can process the discharge discharged from the sewage treatment system. On the one hand, it can realize the recovery and utilization of fine sand in the discharge, and on the other hand, it can also realize the discharge control of sludge concentration, thereby solving the problems of excessive sand loss in traditional sand-added high-efficiency sedimentation tanks and excessively high water content of residual sludge discharge.

[0019] Furthermore, compared with the related art, the present invention has at least the following additional advantages.

[0020] (1) Energy-saving operation and low failure rate: This device uses the natural head difference of the original system as the power source and does not require additional electric energy to drive it. Therefore, the operating cost is extremely low and it is energy-saving and environmentally friendly. In addition, there are no complex mechanical moving parts inside the device, and the structure is simple and reliable, which reduces the possibility of failure and reduces maintenance costs.

[0021] (2) Efficient recovery of fine sand: The unique design enables secondary recovery of fine sand, reducing the amount of fine sand required to be replenished daily from 4-6 mg / L to 2-3 mg / L, thereby reducing the consumption of fine sand and saving operating costs.

[0022] (3) Good sludge concentration effect: This device can concentrate the system sludge, reducing the moisture content of the discharged residual sludge from 99.2~99.6% to 98~99%, thereby increasing the solid content of the residual sludge and reducing the burden of subsequent sludge treatment.

[0023] (4) Improve sedimentation tank performance: The device can increase the concentration of sludge in the sand-added high-efficiency sedimentation tank, enhance the sedimentation tank's ability to resist the impact of suspended matter, and improve the system's processing capacity and effluent quality.

[0024] (5) Reduce equipment wear: By effectively recovering fine sand, the content of fine sand in the discharged residual sludge is reduced, the wear degree of subsequent sludge treatment system equipment is reduced, and the service life of the equipment is extended.

[0025] (6) System optimization: The proportion of fine sand in the sedimentation tank was increased from 2% to 4% of the total volume of the sedimentation tank, which accelerated the sedimentation rate of flocculent sludge in the system and thereby improved the effluent water quality standards. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1 It is a structural diagram of a sewage treatment system provided by relevant technology.

[0028] Figure 2 It is a structural schematic diagram of the system fine sand secondary recovery and sludge concentration control device provided by the present invention.

[0029] Figure 3 is along Figure 2 Schematic diagram of the cross-sectional structure along line AA.

[0030] Figure 4 is along Figure 2 Schematic diagram of the cross-sectional structure along line BB.

[0031] Figure 5 It is a schematic diagram of the cross-sectional structure of the cyclone sand collecting area of ​​the system fine sand secondary recovery and sludge concentration control device provided by the present invention.

[0032] Figure 6 It is a schematic diagram of the steps of the control method of the system fine sand secondary recovery and sludge concentration control device provided by the present invention.

[0033] Figure 7 It is a structural schematic diagram of the sewage treatment system provided by the present invention.

[0034] Figure 8 It is a structural schematic diagram of the electronic device provided by the present invention.

[0035] Reference numerals: 1. Raw water; 2. Coagulation contact tank; 3. Coagulation sand adding tank; 4. Flocculation tank; 5. Inclined plate sedimentation tank; 6. Purified effluent; 7. Hydrocyclone; 8. Sediment return pipe; 9. Residual sludge discharge pipe; 10. System fine sand secondary recovery and sludge concentration control device; 11. Sediment secondary recovery pipe; 20. Box; 21. Mud inlet; 22. Mud inlet buffer area; 23. Cyclone sand collection area; 24. Scum collection area; 25. Sludge secondary sedimentation area; 26. Overflow mud discharge area; 27. Sludge discharge port; 28. Recovered sand outlet; 29. ​​Scum discharge port; 30. Sand collecting shell; 31. Sand collecting area entrance; 32. Water inlet diversion area; 33. Cyclone reflection area; 34. Fine sand precipitation area; 35. Cyclone separation layer; 36. Mud discharge stabilization layer; 37. Sand collecting area outlet; 38. Fine sand discharge area; 41. Mud inlet pipeline; 42. Diversion center tube; 43. Diversion reflection plate; 44. Bottom connecting ring; 51. First regulating valve; 52. Second regulating valve; 53. Residual sludge discharge flow meter; 54. Third regulating valve; 55. Sludge passing hole; 56. Overflow structure; 57. Overflow hole. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] The following describes a system fine sand secondary recovery and sludge concentration control device, a control method for the system fine sand secondary recovery and sludge concentration control device, and a sewage treatment system having the system fine sand secondary recovery and sludge concentration control device, provided by the present invention, with reference to the accompanying drawings. First of all, it should be explained that the system fine sand secondary recovery and sludge concentration control device of the present invention is used to treat the discharge mixed with sludge, scum and fine sand discharged from the sewage treatment system. On the one hand, the device can realize the recovery of fine sand, and on the other hand, it can realize the controllable concentration of sludge to facilitate the subsequent sludge treatment process.

[0038] like Figures 2 to 7 As shown, the system fine sand secondary recovery and sludge concentration control device 10 according to the first aspect of the embodiment of the present invention includes a mud inlet buffer area 22, a cyclone sand collection area 23, a scum collection area 24, a sludge secondary sedimentation area 25 and an overflow mud discharge area 26 which are connected in sequence.

[0039] The mud inlet buffer area 22 has a mud inlet 21, which is connected to the discharge port of the sewage treatment system to receive the discharge of the system.

[0040] The cyclone sand collecting area 23 is connected with the mud inlet buffer area 22 through the mud inlet pipe 41, and a cylindrical cyclone space is formed inside the cyclone sand collecting area 23. The mud inlet pipe 41 extends along the tangential direction of the cyclone space so that the discharge forms a cyclone, and a fine sand sedimentation area 34 is formed at the bottom of the cyclone space, and the fine sand sedimentation area 34 is connected to the outside through the recovered sand outlet 28; a sand collecting area outlet 37 is formed at the top of the cyclone space, wherein, under the action of the cyclone, the fine sand in the discharge falls into the fine sand sedimentation area 34, and the scum and sludge in the discharge are discharged through the sand collecting area outlet 37.

[0041] The scum collection area 24 is connected to the sand collection area outlet 37 of the cyclone sand collection area 23, and the scum collection area 24 is connected to the outside through the scum discharge port 29; the sludge secondary sedimentation area 25 is connected to the scum collection area 24 through the sludge through hole 55, and the sludge in the scum collection area 24 enters the sludge secondary sedimentation area 25 through the sludge through hole 55; an overflow structure 56 is provided at the top of the overflow mud discharge area 26, and the sludge secondary sedimentation area 25 is connected to the overflow mud discharge area 26 through the overflow structure 56, and the overflow mud discharge area 26 is connected to the outside through the sludge discharge port 27.

[0042] For ease of understanding, the specific structure and working principle of each component in the device of the present invention will be introduced in turn below. It can be understood that the system fine sand secondary recovery and sludge concentration control device 10 is a polyhedral box 20, and various functional areas are formed inside it.

[0043] like Figure 2 As shown, the mud inlet buffer area 22 has a mud inlet 21, which is directly connected to the discharge port of the sewage treatment system and is used to receive the residual sludge discharged by the system. It can be understood that the function of the mud inlet buffer area 22 is to receive the residual sludge from the sewage treatment system, which contains fine sand, scum and other impurities. In this way, through the mud inlet buffer area 22, the flow of sludge can be effectively controlled so that it can smoothly enter the next treatment link.

[0044] A cylindrical cyclone space is formed inside the cyclone sand collecting area 23, and the mud inlet pipe 41 is arranged along the tangential direction of the cyclone space, so that the discharge can form a cyclone when entering the cyclone space. It can be understood that under the action of the cyclone, the fine sand particles with higher density sink to the fine sand precipitation area 34 at the bottom due to the centrifugal force, while the scum and residual sludge with lower density rise with the water flow and are discharged from the sand collecting area outlet 37. In this way, the fine sand is effectively separated from the scum and residual sludge through the cyclone sand collecting area 23.

[0045] The scum collecting area 24 is connected to the sand collecting area outlet 37 of the cyclone sand collecting area 23, and discharges the scum out of the device through the scum discharge port 29. It can be understood that the scum collecting area 24 is used to collect the scum material rising with the water flow and discharge it through the scum discharge port 29. In this way, the scum collecting area 24 ensures that the scum will not interfere with the subsequent processing process, ensuring the purity of the fine sand recovery.

[0046] The sludge secondary sedimentation zone 25 is connected to the sludge collection zone 24 through the sludge through holes 55, and the sludge in the sludge collection zone 24 can enter the sludge secondary sedimentation zone 25 through these holes. It can be understood that in the sludge secondary sedimentation zone 25, the sludge is further precipitated, wherein the fine sand that is not completely recovered is further settled in this area, and flows to the fine sand discharge zone 38 through the connection with the fine sand sedimentation zone 34. In this way, the sludge secondary sedimentation zone 25 helps to improve the recovery rate of fine sand and further concentrate the excess sludge.

[0047] An overflow structure 56 is provided at the top of the overflow mud discharge area 26, which is connected to the sludge secondary sedimentation area 25 through the overflow structure 56. The overflow mud discharge area 26 discharges the remaining sludge through the sludge discharge port 27. It can be understood that when the sludge in the sludge secondary sedimentation area 25 reaches a certain height, the excess sludge enters the overflow mud discharge area 26 through the overflow structure 56 and is then discharged through the sludge discharge port 27. In this way, the overflow mud discharge area 26 ensures the appropriate concentration of sludge in the system and prevents sludge overflow from causing pollution.

[0048] Further, based on the above description of each functional component in the device, the overall working principle and process of the device are as follows: the operation of the entire device starts from the sludge inlet buffer area 22, receives the residual sludge from the sewage treatment system, and then separates the fine sand from the scum and residual sludge through the cyclone action of the cyclone sand collecting area 23. The fine sand settles at the bottom of the cyclone sand collecting area 23 and is discharged back into the system through the sand recovery outlet 28, while the scum is collected and discharged through the scum discharge port 29. The residual sludge enters the sludge secondary sedimentation area 25 through the scum collection area 24 for further sedimentation, and is finally discharged through the overflow structure 56 of the overflow mud discharge area 26. In the whole process, the fine sand is efficiently recovered for the second time, and the residual sludge discharged from the system is concentrated to the required concentration range.

[0049] In the related technology, usually Figure 1The technical scheme is used to achieve sewage treatment, in which the raw water to be purified passes through the coagulation contact tank, coagulation and sand adding tank, flocculation tank, and inclined plate sedimentation tank of the sand adding high-efficiency sedimentation tank in turn to obtain purified water. The traditional sand and sludge mixture at the bottom of the inclined plate sedimentation tank is pumped into the hydrocyclone through a circulating pump, and most of the fine sand enters the coagulation and sand adding tank from the lower sediment return pipe. The rest of the sludge goes to the residual sludge tank from the upper pipe and is discharged into the concentration tank. In order to maintain a stable concentration of sludge and fine sand in the sedimentation tank, the circulating pump must be turned on continuously, and the hydrocyclone also works continuously for 24 hours.

[0050] Therefore, the technical solutions in the above-mentioned related technologies will bring the following technical defects.

[0051] (1) Difficulty in controlling sludge concentration: In traditional methods, a circulating pump is used to maintain a stable concentration of sludge and fine sand in the sedimentation tank. However, in actual operation, it is found that the sludge discharge volume cannot be accurately controlled by relying solely on the variable frequency control flow of the circulating pump, resulting in difficulty in maintaining an ideal sludge concentration.

[0052] (2) Fine sand loss problem: When the system is operating in a steady state, the upper sludge still contains a large amount of fine sand, resulting in a large loss of fine sand. A large amount of fine sand needs to be replenished every day, which increases the operating cost.

[0053] (3) High moisture content of residual sludge: Under traditional methods, the moisture content of residual sludge is very high, which not only increases the difficulty of subsequent treatment, but also causes a large water impact on subsequent sludge disposal, reducing the desludge efficiency.

[0054] (4) Severe equipment wear: Since a large amount of fine sand is discharged with the residual sludge, this causes serious wear on the subsequent sludge deep treatment system equipment, making the equipment easily damaged and increasing maintenance costs.

[0055] (5) Difficulty in controlling the reflow ratio: If the circulating pump is turned on too high, the moisture content of the residual sludge will be too high, while if it is turned on too low, the sediment separation effect will be affected. Therefore, it is difficult to find a suitable reflow ratio to meet the needs of fine sand recovery and sludge thickening at the same time.

[0056] In summary, in order to solve the technical defects existing in the above-mentioned related technologies, the present invention provides a system fine sand secondary recovery and sludge concentration control device 10, which can treat the emissions discharged from the sewage treatment system. On the one hand, it can realize the recycling of fine sand in the emissions, and on the other hand, it can also realize the emission control of sludge concentration, thereby solving the problems of excessive sand loss in traditional sand-added high-efficiency sedimentation tanks and excessively high moisture content of residual sludge discharge.

[0057] Furthermore, compared with the related art, the present invention has at least the following additional advantages.

[0058] (1) Energy-saving operation and low failure rate: This device uses the natural head difference of the original system as the power source and does not require additional electric energy to drive it. Therefore, the operating cost is extremely low and it is energy-saving and environmentally friendly. In addition, there are no complex mechanical moving parts inside the device, and the structure is simple and reliable, which reduces the possibility of failure and reduces maintenance costs.

[0059] (2) Efficient recovery of fine sand: The unique design enables secondary recovery of fine sand, reducing the amount of fine sand required to be replenished daily from 4-6 mg / L to 2-3 mg / L, thereby reducing the consumption of fine sand and saving operating costs.

[0060] (3) Good sludge concentration effect: This device can concentrate the system sludge, reducing the moisture content of the discharged residual sludge from 99.2~99.6% to 98~99%, thereby increasing the solid content of the residual sludge and reducing the burden of subsequent sludge treatment.

[0061] (4) Improve sedimentation tank performance: The device can increase the concentration of sludge in the sand-added high-efficiency sedimentation tank, enhance the sedimentation tank's ability to resist the impact of suspended matter, and improve the system's processing capacity and effluent quality.

[0062] (5) Reduce equipment wear: By effectively recovering fine sand, the content of fine sand in the discharged residual sludge is reduced, the wear degree of subsequent sludge treatment system equipment is reduced, and the service life of the equipment is extended.

[0063] (6) System optimization: The proportion of fine sand in the sedimentation tank was increased from 2% to 4% of the total volume of the sedimentation tank, which accelerated the sedimentation rate of flocculent sludge in the system and thereby improved the effluent water quality standards.

[0064] like Figure 2 As shown, according to some embodiments of the present invention, a first regulating valve 51 with adjustable opening is provided at the recovered sand outlet 28, a second regulating valve 52 with adjustable opening is provided at the sludge discharge outlet 27, and a third regulating valve 54 with adjustable opening is provided at the slag discharge outlet 29.

[0065] In this embodiment, the first regulating valve 51 is installed at the position of the recovered sand outlet 28 to control the amount of fine sand recovered. By adjusting the opening of this valve, the proportion of fine sand returning to the sewage treatment system can be accurately controlled. This helps to maintain a stable concentration of fine sand inside the sewage treatment system, reduce the waste of fine sand, and keep the sewage treatment system in the best state of operation.

[0066] The second regulating valve 52 is installed at the position of the sludge discharge port 27 to control the discharge amount of the excess sludge. By adjusting the opening of this valve, the discharge ratio of the excess sludge in the system can be changed, thereby realizing the control of the sludge concentration in the system. When the excess sludge needs to be concentrated, the opening of this valve can be reduced to allow more sludge to flow back into the system; conversely, if more excess sludge needs to be discharged, the valve opening can be increased.

[0067] The third regulating valve 54 is installed at the position of the scum discharge port 29 to control the discharge amount of the scum. By adjusting the opening of this valve, the discharge amount of the scum can be adjusted to ensure that the scum in the system does not accumulate too much and affect the treatment effect. At the same time, for the scum that needs to be reprocessed, the scum can be recycled by controlling this valve.

[0068] In summary, the setting of these three regulating valves allows the operator to flexibly adjust the material flow inside the system according to actual needs, thereby achieving effective control of fine sand recovery, sludge concentration and scum discharge, ensuring that the system operates in the best state. This design is conducive to improving the automation of the system, simplifying the operation process, and also helping to improve the efficiency and quality of sewage treatment.

[0069] like Figure 3 and Figure 5 As shown, according to some embodiments of the present invention, the cyclone sand collecting area 23 further includes a flow guiding center cylinder 42, which extends along the central axis of the cyclone space and the central axes of the two coincide with each other.

[0070] In the height direction of the cyclone space, the flow guiding center tube 42 is disposed opposite to the mud inlet pipe 41 and the sand collecting area outlet 37 respectively.

[0071] In this embodiment, the flow guiding center tube 42 is a structure extending along the central axis of the cyclone space, and coincides with the central axis of the cyclone space. In the height direction of the cyclone space, the flow guiding center tube 42 is arranged at a position corresponding to the mud inlet pipe 41 and the sand receiving area outlet 37, and such a design helps to guide and optimize the fluid movement in the cyclone space.

[0072] Its working principle is as follows: when the sand-containing residual sludge enters the cyclone space through the mud inlet pipe 41, the sludge will form a cyclone because the mud inlet pipe 41 extends along the tangential direction of the cyclone space. The existence of the guide center tube 42 helps to form a stable cyclone field, so that the fluid forms a central vortex in the cyclone space, which can enhance the separation effect between fine sand and lighter scum and residual sludge. At the outlet 37 of the sand collecting area formed at the top of the cyclone space, the lighter scum and residual sludge will pass upward through the gap around the guide center tube 42 and finally enter the scum collection area 24. The design of the guide center tube 42 can also help maintain the dynamic balance of the fluid in the cyclone space, prevent the cyclone from being unstable or turbulent, thereby improving the separation efficiency. It can be understood that the guide center tube 42 not only helps to form and maintain a stable cyclone, but also optimizes the separation process of fine sand and other substances, thereby improving the recovery efficiency of fine sand and the overall performance of the system.

[0073] Thus, on the one hand, with the help of the flow guiding center cylinder 42, the fine sand is more easily separated under the action of centrifugal force and falls into the fine sand settling area 34; on the other hand, the scum and the remaining sludge are discharged through the sand collecting area outlet 37, so that the fine sand can be effectively separated from the scum and the remaining sludge, and the recovery rate of the fine sand can be improved. At the same time, the flow guiding center cylinder 42 also helps to improve the stability and reliability of the system and reduce the problem of reduced separation efficiency caused by unstable fluid movement.

[0074] like Figure 3 and Figure 5 As shown, further, the cyclone sand collecting area 23 also includes a guide reflector 43, which is truncated cone-shaped and whose central axis coincides with the central axis of the guide center tube 42, and the end of the guide reflector 43 with a small diameter is connected to the bottom end of the guide center tube 42.

[0075] In the height direction of the cyclone space, the guide reflection plate 43 is located between the mud inlet pipe 41 and the fine sand precipitation area 34 .

[0076] In this embodiment, the guide reflector 43 is a truncated cone-shaped structure, and its central axis coincides with the central axis of the guide center tube 42, so as to ensure that the movement of the fluid in the cyclone space is more regular. Among them, the end of the guide reflector 43 with a smaller diameter is connected to the bottom end of the guide center tube 42, and the larger end is toward the periphery of the cyclone space. Such a design helps to guide the movement trajectory of the fluid in the cyclone space. In the height direction of the cyclone space, the guide reflector 43 is located between the mud inlet pipe 41 and the fine sand precipitation area 34, so that the flow direction of the fluid in the cyclone space can be effectively controlled.

[0077] Its working principle is as follows: when the sand-containing residual sludge enters the cyclone space through the sludge inlet pipe 41, the fluid will first contact the guide reflector 43. The design of the guide reflector 43 enables the fluid to form a two-way cyclone. The residual sludge and scum with lower density pass upward through the sand collection area outlet 37 under the action of the cyclone and finally enter the scum collection area 24. The fine sand with higher density is affected by the centrifugal force and falls along the surface of the guide reflector 43 to the fine sand precipitation area 34 below. It can be understood that the guide reflector 43 effectively promotes the orderly movement of the fluid in the cyclone space through its truncated cone design and position arrangement, and enhances the separation effect of fine sand, scum and residual sludge.

[0078] In this way, the guide reflector 43 helps to enhance the cyclone effect, so that the fine sand and the scum and the residual sludge are better separated. On the one hand, through the design of the guide reflector 43, the fine sand can form a more concentrated sinking trajectory in the cyclone space, which helps to improve the recovery efficiency of the fine sand; on the other hand, the guide reflector 43 can also help reduce the rebound of the fine sand in the cyclone space, and prevent the fine sand from being discharged together with the scum and the residual sludge.

[0079] like Figure 3 As shown, according to some embodiments of the present invention, a fine sand discharge area 38 is provided outside the fine sand sedimentation area 34 , and the fine sand discharge area 38 is respectively connected to the fine sand sedimentation area 34 and the sludge secondary sedimentation area 25 , and the recovered sand outlet 28 is provided on the side wall of the fine sand discharge area 38 .

[0080] In this embodiment, the fine sand discharge area 38 is located outside the fine sand sedimentation area 34 and is connected to the fine sand sedimentation area 34 and the sludge secondary sedimentation area 25. The recovered sand outlet 28 is provided on the side wall of the fine sand discharge area 38, so that the fine sand can be smoothly recovered through this outlet and sent back to the sand adding high-efficiency sedimentation tank system.

[0081] Specifically, the fine sand discharge area 38 is designed to collect the settled fine sand and discharge it through the recovered sand outlet 28 for reuse. Through the connection between the fine sand discharge area 38 and the fine sand sedimentation area 34, the fine sand can flow into the fine sand discharge area 38 by gravity after sedimentation. The connection between the sludge secondary sedimentation area 25 and the fine sand discharge area 38 allows the fine sand that failed to settle completely in the first sedimentation to also flow into the fine sand discharge area 38 after the secondary sedimentation.

[0082] Thus, the design of the fine sand discharge area 38 enables the fine sand to be concentrated and discharged smoothly, thereby improving the efficiency of fine sand recovery. In addition, the connection between the fine sand discharge area 38 and the two sedimentation areas ensures multiple recovery opportunities for the fine sand, ensuring that as much fine sand as possible is recycled.

[0083] Furthermore, in the direction from the fine sand settling area 34 to the fine sand discharge area 38, a first sand guide slope (not shown in the figure) with a gradually decreasing height is provided at the bottom of the system fine sand secondary recovery and sludge concentration control device 10. In this way, the design of the first sand guide slope helps the fine sand to slide toward the fine sand discharge area 38 under the action of gravity, thereby ensuring that the fine sand can smoothly flow into the fine sand discharge area 38 and be discharged through the recovered sand outlet 28.

[0084] In the direction from the sludge secondary sedimentation area 25 to the fine sand discharge area 38, a second sand guide slope (not shown in the figure) with a gradually decreasing height is provided at the bottom of the system fine sand secondary recovery and sludge concentration control device 10. Thus, the second sand guide slope is also designed to ensure that the fine sand that has not been completely settled in the primary sedimentation can slide smoothly to the fine sand discharge area 38 after the secondary sedimentation.

[0085] In summary, the design of the fine sand discharge area 38 and the application of the sand guide slope ensure that the fine sand can be effectively collected and discharged through the recovered sand outlet 28, thereby improving the recovery efficiency of the fine sand. In addition, the design of the sand guide slope allows the fine sand to naturally slide to the fine sand discharge area 38 under the action of gravity, reducing the possibility of fine sand being retained in the system and reducing the loss of fine sand.

[0086] For example Figures 2 to 5 As shown, the sand-containing excess sludge passes through the sand collection area inlet 31 and enters the sand collection area shell. Under the guidance of the mud inlet pipe 41, the sand-containing excess sludge swirls in the water inlet diversion area 32, and forms a two-way swirl under the joint action of the diversion center tube 42 and the diversion reflector 43. The excess sludge with a density of 1.06 Kg / m3 passes upward through the swirl separation layer 35 and the mud outlet stabilization layer 36, and finally enters the scum collection area 24 through the sand collection area outlet 37. The fine sand with a real density of about 2650 Kg / m3 falls into the fine sand precipitation area 34 along the diversion reflector 43 through the swirl reflection area 33 under the action of centrifugal force. The bottom and surrounding of the fine sand precipitation area 34 are connected to the outer fine sand discharge area 38 through the bottom connecting ring 44, and the fine sand can flow into the fine sand discharge area 38 along the internal slope. Finally, the fine sand is discharged back to the coagulation and sand adding tank 3 through the recovery sand outlet 28, so as to achieve the purpose of secondary recovery of fine sand.

[0087] The bottoms of the sludge secondary sedimentation area 25, the fine sand sedimentation area 34 and the fine sand discharge area 38 of the device are interconnected, and the fine sand deposited at the bottom can eventually generate discharge power under the vortex action in the fine sand sedimentation area 34, and finally be discharged back to the coagulation and sand adding tank 3 through the recovered sand outlet 28, so as to achieve the purpose of fine sand recovery.

[0088] like Figure 2As shown, according to some embodiments of the present invention, a sludge through hole 55 is provided at the bottom of the sludge collection area 24. It can be understood that this design is to allow the sludge in the sludge collection area 24 to enter the sludge secondary sedimentation area 25 through this hole.

[0089] In the actual treatment process, the remaining sludge and scum after separation in the cyclone sand collecting area 23 will be transported to the scum collecting area 24. The sludge at the bottom of the scum collecting area 24 enters the sludge secondary sedimentation area 25 through the hole 55 for further sedimentation treatment. This design ensures that the sludge stays in the sludge collecting area 24 for a sufficient time to remove most of the scum before entering the sludge secondary sedimentation area 25 for more refined treatment.

[0090] Thus, the design of the sludge through hole 55 allows the sludge to flow naturally into the sludge secondary sedimentation area 25 under the action of gravity, thereby reducing energy consumption. In addition, the separation design of the scum collection area 24 and the sludge secondary sedimentation area 25 allows the scum to be effectively removed in the scum collection area 24, while the sludge can be more thoroughly processed in the secondary sedimentation area, thereby improving the sludge concentration effect.

[0091] like Figure 2 As shown, according to some embodiments of the present invention, the inlet sludge buffer area 22 is connected to the sludge secondary sedimentation area 25 through an overflow hole 57 provided at the top thereof. It can be understood that the overflow hole 57 is designed to handle the situation where the inlet sludge buffer area 22 exceeds the capacity.

[0092] The working principle of the overflow hole 57 is as follows: when the amount of sludge in the sludge buffer area 22 reaches a certain height, the excess sludge will flow into the sludge secondary sedimentation area 25 through the overflow hole 57. This is done to prevent the sludge buffer area 22 from being overfilled and causing sludge overflow, while ensuring that the system can operate continuously and stably.

[0093] In this way, the design of the overflow hole 57 ensures that the sludge buffer area 22 will not overflow due to excessive sludge, thereby maintaining the normal operation of the system. Further, the excess sludge entering the sludge secondary sedimentation area 25 through the overflow hole 57 can continue to be processed, avoiding the waste of sludge.

[0094] Furthermore, in the design structure of the above device, the reasonable hole design allows the sludge to smoothly transition between different treatment stages, reducing the stagnation time of the sludge in the system and improving the treatment efficiency. The above design reduces the need for manual intervention, making the system more automated, simplifying the operation process and reducing maintenance costs.

[0095] like Figure 2 As shown, according to some embodiments of the present invention, the overflow structure 56 is an overflow weir arranged on the top of the overflow mud discharge area 26, and the overflow weir is sawtooth-shaped and extends along the top wall of the overflow mud discharge area 26.

[0096] It should be explained that the overflow weir in this embodiment is a structure arranged at the top of the overflow mud discharge area 26, which is distributed in a zigzag shape and extends along the top wall of the overflow mud discharge area 26. The zigzag design enables the overflow weir to have multiple high and low staggered edges, which can control the flow mode of the sludge when passing through the overflow weir.

[0097] Specifically, its working principle is as follows: when the amount of sludge in the sludge secondary sedimentation area 25 exceeds the set height, the excess sludge will overflow through the overflow weir and flow into the overflow sludge discharge area 26. The design of the serrated overflow weir allows the sludge to pass through multiple small drops when overflowing, which helps to further separate fine sand and other impurities in the sludge, because the fine sand may settle again when flowing through the serrated edge, while the lighter sludge continues to move forward with the water flow.

[0098] In this way, the serrated overflow weir design can distribute the overflow sludge more evenly, reduce the risk of local overload, and ensure the stability of system operation. In addition, through the multiple small drops of the serrated edge, the recovery efficiency of fine sand can be further improved, and the possibility of fine sand being discharged with the sludge can be reduced. In addition, the serrated design can also increase the surface area of ​​the water flow, which helps to improve the separation effect of sludge and reduce the fine sand content in the discharged sludge.

[0099] It should be pointed out that the overflow structure 56 may also adopt other structures, and the present invention does not make any special limitation here, as long as the overflow structure 56 can achieve the function of overflow connection.

[0100] The control method, control device and system fine sand secondary recovery and sludge concentration control device 10 of the system fine sand secondary recovery and sludge concentration control device 10 proposed in the present invention are described below with reference to the accompanying drawings. Among them, before the embodiment of the present invention is described in detail, the entire application scenario is first described. The control method, control device, electronic device and computer-readable storage medium of the system fine sand secondary recovery and sludge concentration control device 10 of the embodiment of the present invention can be applied to the system fine sand secondary recovery and sludge concentration control device 10 locally, and can also be applied to the cloud platform in the Internet field, or other types of cloud platforms in the Internet field, or can also be applied to third-party devices. Among them, third-party devices may include many different types such as mobile phones, tablet computers, notebooks, car computers and other smart terminals.

[0101] The following is an explanation of the control method applicable to the system fine sand secondary recovery and sludge concentration control device 10 as an example. It should be understood that the control method of the embodiment of the present invention can also be applied to cloud platforms and third-party equipment.

[0102] like Figure 6As shown, the control method of the system fine sand secondary recovery and sludge concentration control device 10 according to the second embodiment of the present invention includes: Step S1, obtaining the target concentration range of the sludge discharged from the system; Step S2, controlling and adjusting the openings of the first regulating valve 51 and the second regulating valve 52 according to the target concentration range.

[0103] According to the control method of the system fine sand secondary recovery and sludge concentration control device 10 of the embodiment of the present invention, the specific working process is as follows: First, the state of the residual sludge discharged by the system is monitored in real time through the flow meter and the mud level monitor, and the target concentration range is set. According to the target concentration range, the opening of the first regulating valve 51 and the second regulating valve 52 are adjusted by the automatic control system algorithm.

[0104] Specifically, if the concentration of sludge in the system needs to be increased, the opening of the second regulating valve 52 can be appropriately reduced, while the opening of the first regulating valve 51 can be increased to allow more sludge to flow back. If the concentration of sludge in the system needs to be reduced, the opening of the second regulating valve 52 can be appropriately increased, while the opening of the first regulating valve 51 can be reduced to allow more sludge to be discharged.

[0105] Furthermore, the system will compare the actual concentration of discharged sludge with the target concentration range, and automatically adjust the opening of the two regulating valves according to the deviation until the set target concentration range is reached.

[0106] In this way, through the above steps, the system fine sand secondary recovery and intelligent control of the sludge concentration control device 10 can be achieved, ensuring that the discharged residual sludge reaches the ideal concentration range, which not only improves the operating efficiency of the system but also reduces the cost of subsequent processing.

[0107] In practical applications, the device of the present invention realizes the control of system sludge concentration by controlling the first regulating valve 51 and the second regulating valve 52. Some specific embodiments of the control method of the present invention are given below.

[0108] 1) When the first regulating valve 51 is fully opened, the device refluxes all incoming sludge regardless of the opening degree of the second regulating valve 52. At this time, the device of the present invention does not discharge excess sludge.

[0109] 2) When the first regulating valve 51 is fully closed, the second regulating valve 52 is fully opened through program linkage. At this time, the device is only equivalent to short-circuiting, and all the remaining sludge is discharged, and fine sand is not recovered. However, if the third electric valve is opened at this time, it can play the role of system scum recovery and reprocessing.

[0110] 3) The second regulating valve 52 is fully opened or moderately closed. At this time, the proportion of sludge returning to the system can be controlled by adjusting the opening of the first regulating valve 51. When the opening of the first regulating valve 51 is larger, the sludge return volume is larger, and the residual sludge discharge volume is smaller. At this time, the sludge in the system is concentrated, and the water content of the discharged chemical residual sludge is lower, so the residual sludge concentration effect is better.

[0111] 4) The second regulating valve 52 is fully opened or moderately closed. If the opening of the first regulating valve 51 is smaller, the sludge return volume will be smaller and the residual sludge discharge volume will be larger. At this time, the sludge concentration in the system will decrease, and the water content of the discharged chemical residual sludge will increase, thereby reducing the residual sludge concentration effect.

[0112] 5) In addition, Example 3) and Example 4) can be further combined with the flow meter and the mud level monitor of the inclined plate sedimentation tank 5, and the opening size of the first regulating valve 51 and the second regulating valve 52 can be remotely controlled through the automatic control system algorithm, so that the chemical residual sludge discharged from the system can be concentrated to the required concentration range to meet the target requirements.

[0113] like Figure 7 As shown, the present invention also protects a sewage treatment system, which includes a system fine sand secondary recovery and sludge concentration control device 10 as described in the embodiment of the first aspect of the present invention, and also includes a coagulation contact tank 2, a coagulation sand adding tank 3, a flocculation tank 4, and an inclined plate sedimentation tank 5 connected in sequence.

[0114] Among them, the inclined plate sedimentation tank 5 is connected to the hydrocyclone 7 through the purified water outlet 6, the sediment return pipe 8 of the hydrocyclone 7 is connected to the coagulation and sand adding tank 3, and the residual sludge discharge pipe 9 of the hydrocyclone 7 is connected to the mud inlet 21 of the system fine sand secondary recovery and sludge concentration control device 10, and the recovered sand outlet 28 of the system fine sand secondary recovery and sludge concentration control device 10 is also connected to the coagulation and sand adding tank 3.

[0115] According to the sewage treatment system of the embodiment of the present invention, its specific working process is as follows: the raw water 1 is treated in the coagulation contact tank 2, the coagulation sand adding tank 3 and the flocculation tank 4 in turn, and the coagulant and sand medium are added to promote the coagulation and flocculation of pollutants. The pretreated sewage enters the inclined plate sedimentation tank 5, where the mud and water are separated by gravity, and the purified water is discharged from the system. : The separated sludge enters the hydrocyclone 7, most of the fine sand returns to the coagulation sand adding tank 3 through the sediment return pipe 8, and the remaining sludge enters the system fine sand secondary recovery and sludge concentration control device 10. In the system fine sand secondary recovery and sludge concentration control device 10, the remaining sludge is separated by cyclone, and the fine sand returns to the coagulation sand adding tank 3 through the recovered sand outlet 28, and the concentrated remaining sludge is discharged from the system through the sludge discharge port 27.

[0116] In summary, through this series of treatment steps, efficient recovery of fine sand and concentration of residual sludge are achieved, which improves the overall efficiency and operation effect of the sewage treatment system.

[0117] Figure 8 An example of a physical structure diagram of an electronic device is shown in FIG. Figure 8 As shown, the electronic device may include: a processor 810, a communications interface 820, a memory 830 and a communication bus 840, wherein the processor 810, the communications interface 820 and the memory 830 communicate with each other through the communication bus 840. The processor 810 may call the logic instructions in the memory 830 to execute the control method of the system fine sand secondary recovery and sludge concentration control device 10, including: obtaining the target concentration range of the system discharged sludge; and controlling and adjusting the opening of the first regulating valve 51 and the second regulating valve 52 according to the target concentration range.

[0118] In addition, the logic instructions in the above-mentioned memory 830 can be implemented in the form of a software functional unit and can be stored in a computer-readable storage medium when it is sold or used as an independent product. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods of each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc. Various media that can store program codes.

[0119] On the other hand, the present invention also provides a computer program product, which includes a computer program. The computer program can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can execute the control method of the system fine sand secondary recovery and sludge concentration control device 10 provided by the above methods, including: obtaining the target concentration range of the system discharged sludge; according to the target concentration range, controlling and adjusting the opening of the first regulating valve 51 and the second regulating valve 52.

[0120] On the other hand, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, it is implemented to execute the control method of the system fine sand secondary recovery and sludge concentration control device 10 provided by the above-mentioned methods, including: obtaining the target concentration range of the system discharged sludge; according to the target concentration range, controlling and adjusting the opening of the first regulating valve 51 and the second regulating valve 52.

[0121] The device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, i.e., they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Those of ordinary skill in the art may understand and implement it without creative effort.

[0122] Through the description of the above implementation modes, those skilled in the art can clearly understand that each implementation mode can be implemented by means of software plus a necessary general hardware platform, or of course by hardware. Based on such an understanding, the above technical solution can essentially or in other words be embodied in the form of a software product that contributes to the prior art. The computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a magnetic disk, an optical disk, etc., and includes a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods of each embodiment or some parts of the embodiment.

[0123] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A system fine sand secondary recovery and sludge concentration control device, characterized in that: include: A mud inlet buffer area having a mud inlet, wherein the mud inlet is connected to a discharge outlet of the sewage treatment system for receiving discharge from the system; A cyclone sand collecting area is connected with the sludge inlet buffer area through a sludge inlet pipe, and a cylindrical cyclone space is formed inside the cyclone sand collecting area. The sludge inlet pipe extends along the tangential direction of the cyclone space so that the discharge forms a cyclone, and a fine sand sedimentation area is formed at the bottom of the cyclone space, and the fine sand sedimentation area is connected to the outside through a recovered sand outlet; a sand collecting area outlet is formed at the top of the cyclone space, wherein, under the action of the cyclone, the fine sand in the discharge falls into the fine sand sedimentation area, and the scum and sludge in the discharge are discharged through the sand collecting area outlet; A scum collecting area is connected to the sand collecting area outlet of the cyclone sand collecting area, and the scum collecting area is connected to the outside through a scum discharge port; A sludge secondary sedimentation zone is connected to the sludge collection zone through a sludge through hole, and the sludge in the sludge collection zone enters the sludge secondary sedimentation zone through the sludge through hole; The overflow mud discharge area is provided with an overflow structure on the top of the overflow mud discharge area, the sludge secondary sedimentation area is connected with the overflow mud discharge area through the overflow structure, and the overflow mud discharge area is connected to the outside through the sludge discharge port.

2. The system fine sand secondary recovery and sludge concentration control device according to claim 1 is characterized in that: A first regulating valve with adjustable opening is provided at the recovered sand outlet, and a second regulating valve with adjustable opening is provided at the sludge discharge outlet.

3. The system fine sand secondary recovery and sludge concentration control device according to claim 2 is characterized in that: The cyclone sand collecting area further comprises a flow guiding center cylinder, the flow guiding center cylinder extends along the central axis of the cyclone space and the central axes of the two coincide with each other; In the height direction of the cyclone space, the flow guiding center cylinder is respectively arranged opposite to the mud inlet pipeline and the sand collecting area outlet.

4. The system fine sand secondary recovery and sludge concentration control device according to claim 3 is characterized in that: The cyclone sand collecting area further includes a guide reflector plate, which is in a truncated cone shape and whose central axis coincides with the central axis of the guide central tube, and the end of the guide reflector plate with a smaller diameter is connected to the bottom end of the guide central tube; In the height direction of the cyclone space, the flow guide reflection plate is located between the mud inlet pipe and the fine sand precipitation area.

5. The system fine sand secondary recovery and sludge concentration control device according to any one of claims 2 to 4, characterized in that: A fine sand discharge area is provided outside the fine sand sedimentation area, and the fine sand discharge area is respectively connected with the fine sand sedimentation area and the sludge secondary sedimentation area, and the recovered sand outlet is arranged on the side wall of the fine sand discharge area.

6. The system fine sand secondary recovery and sludge concentration control device according to claim 5 is characterized in that: In the direction from the fine sand sedimentation area to the fine sand discharge area, a first sand guide slope with a gradually decreasing height is provided at the bottom of the system fine sand secondary recovery and sludge concentration control device; And / or, in the direction from the sludge secondary sedimentation zone to the fine sand discharge zone, a second sand guiding slope with a gradually decreasing height is provided at the bottom of the system fine sand secondary recovery and sludge concentration control device.

7. The system fine sand secondary recovery and sludge concentration control device according to any one of claims 2 to 4, characterized in that: The sludge passing hole is arranged at the bottom of the scum collecting area; And / or, the sludge inlet buffer area is connected to the sludge secondary sedimentation area through an overflow hole arranged on the top thereof.

8. The system fine sand secondary recovery and sludge concentration control device according to any one of claims 2 to 4, characterized in that: The overflow structure is an overflow weir arranged at the top of the overflow mud discharge area. The overflow weir is sawtooth-shaped and extends along the top wall of the overflow mud discharge area.

9. A control method for the system fine sand secondary recovery and sludge concentration control device according to any one of claims 2 to 8, characterized in that: include: Obtain the target concentration range of sludge discharged from the system; According to the target concentration range, the openings of the first regulating valve and the second regulating valve are controlled and adjusted.

10. A sewage treatment system, characterized in that: include: The system fine sand secondary recovery and sludge concentration control device according to any one of claims 1 to 8; The coagulation contact tank, the coagulation sand adding tank, the flocculation tank and the inclined plate sedimentation tank are connected in sequence. The inclined plate sedimentation tank is connected to the hydrocyclone through the purified water outlet. The sediment return pipe of the hydrocyclone is connected to the coagulation sand adding tank, and the residual sludge discharge pipe of the hydrocyclone is connected to the mud inlet of the system fine sand secondary recovery and sludge concentration control device, and the recovered sand outlet of the system fine sand secondary recovery and sludge concentration control device is also connected to the coagulation sand adding tank.

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