Sludge secondary concentration device for hard sludge removal of high-hardness wastewater

Abstract

The utility model relates to a sludge secondary concentration device for removing hard sludge from high-hardness wastewater, which is characterized in that the interior of a reactor is sequentially divided into a sludge gradient layer, a natural precipitation layer, a sludge curing layer, a curing sedimentation layer and a clear water layer from bottom to top, and the bottom of the reactor is provided with a sludge discharge port; a flow guide device for feeding high-hardness wastewater into the natural precipitation layer is arranged in the reactor, a sludge secondary ager is arranged in the sludge aging layer, and the sludge circulating device is used for feeding sludge with specified concentration in the sludge gradient layer into the sludge secondary ager. The device has the beneficial effects that when high-hardness sludge in high-hardness wastewater passes through the sludge curing layer, the high-hardness sludge and circulating sludge particle crystals with proper concentration in the sludge secondary curing device are precipitated, so that the crystallization separation capacity of a system is enhanced, and after cured sludge crystal nucleuses are cured, precipitation is accelerated, particulate matter and floc agglomeration is accelerated, and the system quality is improved. And meanwhile, the solid content of the sludge is improved by utilizing a process of gradually compressing to form layered precipitation after adsorption, bridging and netting effects of agglomerated precipitates.

Description

TECHNICAL FIELD

[0001] The utility model relates to sewage treatment technical field, concretely relates to a sludge secondary concentration device for high hardness wastewater hardness removal sludge. BACKGROUND

[0002] High value-added processing industries such as chemical industry, pharmaceutical industry produce a large amount of high hardness wastewater in raw material mother liquor reaction, reaction system acid-base adjustment, distillation residual liquid and other production processes, wherein not only the content of inorganic salt ions K + , Na + , Ca 2+ , Mg 2+ , Cl － , SO4 2－ Is high, often also contains other high concentration pollutants, such as organic matter, ammonia nitrogen, suspended solids, heavy metals, etc.

[0003] High hardness wastewater hardness removal mainly has ion exchange softening method, fluidized bed enhanced crystallization technology, pH precipitation hardness removal method (double reduction method), scale inhibitor hardness removal method, electrochemical softening method, ultrasonic hardness removal method, high frequency polarization hardness removal method, wherein fluidized bed enhanced crystallization technology, pH precipitation hardness removal method (double reduction method) are the most widely used process at present, and are the most stable and safe process, both methods need to form a certain crystal nucleus concentration in the reactor to ensure the crystallization rate of the reaction system and the treatment effect, and the solid content of the hardness removal sludge discharged from the system is generally stabilized at 9% to 11% after stable operation, the sludge volume is still large under this state, and further concentration and dewatering are required for further treatment and disposal.

[0004] At present, the conventional sludge concentration methods have gravity concentration method, air floatation concentration method and centrifugal concentration, and the conventional process has poor sludge concentration effect (the solid content of the bottom sludge is not greater than 12%) for the high concentration sludge under the system, and the high concentration hardness removal sludge is too large for the load of the existing design (there are many solid particles in the effluent), and cannot be stably operated under general design conditions (solid is precipitated to block the water passage).

[0005] Because the conventional sludge concentration process cannot further concentrate the sludge, some enterprises can only select large processing capacity sludge dewatering equipment at the rear end, so that the one-time investment of the operation subject is increased, and the later operation cost is also increased. UTILITY MODEL CONTENT

[0006] The utility model wants to solve the technical problem to provide a kind of sludge secondary concentration device for high-hardness wastewater hard-removal sludge, to solve the existing sludge concentration process concentration effect is poor, effluent water quality stability is poor, pipeline long-time operation after water section reduces, rear-end equipment selection increases, the problem of higher investment.

[0007] The technical scheme for solving the above technical problems is as follows:

[0008] A kind of sludge secondary concentration device for high-hardness wastewater hard-removal sludge, comprising: reactor and sludge circulating device, reactor is sequentially divided into sludge gradient layer, natural sedimentation layer, sludge curing layer, curing settlement layer and clear water layer from bottom to top, sludge discharge port is opened in the bottom of reactor, flow guide device for sending high-hardness wastewater into natural sedimentation layer is arranged in reactor, sludge secondary curing device is arranged in sludge curing layer, sludge circulating device is used to send sludge of specified concentration in sludge gradient layer into sludge secondary curing device.

[0009] The utility model has the advantages that:

[0010] High-hardness wastewater is sent into natural sedimentation layer in reactor by flow guide device, hard-removal sludge in high-hardness wastewater enters sludge curing layer after rectification in natural sedimentation layer, and is fully cured in sludge secondary curing device, and the sludge after curing enters curing settlement layer for secondary separation, supernatant enters clear water layer, and supernatant is discharged after treatment, and settled sludge enters sludge gradient layer, in addition, sludge circulating device sends sludge of specified concentration in sludge gradient layer into sludge secondary curing device;

[0011] By layering design sludge gradient layer, natural sedimentation layer, sludge curing layer, curing settlement layer and clear water layer in reactor, high-hardness wastewater is first sent into natural sedimentation layer, and then passes through sludge curing layer, high-hard sludge in high-hardness wastewater is precipitated with circulating sludge particle crystallization of appropriate concentration in sludge secondary curing device when passing through sludge curing layer, to strengthen the crystallization precipitation capacity of system, accelerate the precipitation of sludge crystal nucleus after curing, speed up the formation of particles and floc, and gradually compress the formation of layered precipitation process by using the adsorption, bridging and net capture effect of precipitate after formation, to achieve the effect of sludge-water separation and improve the solid content of sludge;

[0012] The combination of the sludge circulating device and the sludge secondary ripener can make the sludge concentration system more flexible, improve the stability of the effluent water quality, and improve the stability and impact load capacity of the system operation.

[0013] Based on the above technical solutions, the utility model further can make improvements as follows.

[0014] Further, the reactor is provided with a supernatant outlet in the region corresponding to the clear water layer.

[0015] Based on the above further beneficial effects, the supernatant can be discharged through the supernatant outlet in a self-flowing manner.

[0016] Further, the flow guide device comprises a vertical flow guide cylinder, the upper end of the vertical flow guide cylinder is above the liquid surface line of the clear water layer, the lower end of the vertical flow guide cylinder is connected with the diffusion cylinder, the reflection plates are arranged below the diffusion cylinder at a predetermined interval, the reflection plates are connected with the diffusion cylinder through multiple connecting rods, the gap between the reflection plates and the diffusion cylinder forms a water outlet, the water outlet is in the natural sedimentation layer, the upper end of the vertical flow guide cylinder is provided with a water inlet, and the water inlet penetrates to the outside of the reactor.

[0017] Based on the above further beneficial effects, the high-hardness wastewater enters the vertical flow guide cylinder through the water inlet, then automatically falls by gravity, enters the diffusion cylinder, continues to fall, and falls on the reflection plates, is scattered to the surrounding by impact, and finally enters the natural sedimentation layer from the gap between the reflection plates and the diffusion cylinder.

[0018] Further, the diffusion cylinder is in the shape of a truncated cone, the small-diameter end of the diffusion cylinder is connected with the lower end of the vertical flow guide cylinder, the large-diameter end of the diffusion cylinder is connected with the reflection plates through multiple connecting rods, and the reflection plates are high in the middle and low at the periphery.

[0019] Based on the above further beneficial effects, the reflection plates are high in the middle and low at the periphery, which is beneficial to the scattering of the high-hardness wastewater to the surrounding and the sliding of the sludge by gravity to prevent the accumulation of the sludge on the reflection plates.

[0020] Further, the sludge secondary digester comprises an outer separation cover and an inner separation cover, the inner separation cover is arranged in the upper end port of the outer separation cover, the inner separation cover is fixed on the vertical flow guide cylinder in the flow guide device, a gap is formed between the inner separation cover and the outer separation cover, the inner separation cover is connected with the outer separation cover through a plurality of split connectors, and the inner separation cover is arranged around the sludge distribution pipe at the lower end, a plurality of sludge distribution holes are formed in the sludge distribution pipe, and the sludge circulating device is used to send sludge of a specified concentration in the sludge gradient layer into the sludge distribution pipe in the sludge secondary digester.

[0021] Based on the above further beneficial effects, the sludge circulating device is used to send sludge of a specified concentration in the sludge gradient layer into the sludge distribution pipe in the sludge secondary digester, the sludge entering the sludge distribution pipe is sprayed out of the sludge distribution holes, the baffle design of the sludge secondary digester can achieve the effect of solid-liquid separation, that is, the sludge flow direction is opposite to the conventional sludge flow direction, and the local reduction of the flow section (the gradually reduced flow space formed by the inner and outer separation covers) can achieve the effect of strengthening the separation of sludge and water (the sludge particles in laminar flow are separated from the flow field after touching the separation cover, which is similar to the Hazen shallow sedimentation theory), and the system further intercepts the solid particles.

[0022] Further, the outer separation cover is in the shape of a truncated cone, the upper end of the outer separation cover is a small-diameter end, the lower end of the outer separation cover is a large-diameter end, the inner separation cover is in the shape of a truncated cone, the upper end of the inner separation cover is a large-diameter end, and the lower end of the inner separation cover is a small-diameter end.

[0023] Further, the sludge circulating device comprises a circulating / cleaning pump and a circulating sludge flowmeter, a circulating sludge outlet is formed on the reactor at a region corresponding to the sludge gradient layer, a circulating sludge inlet is formed on the reactor and communicates with the sludge distribution pipe, the inlet of the circulating / cleaning pump communicates with the circulating sludge outlet through a pipeline, the outlet of the circulating / cleaning pump communicates with the circulating sludge inlet through a pipeline, and a circulating sludge flowmeter is arranged on the pipeline between the outlet of the circulating / cleaning pump and the circulating sludge inlet.

[0024] Based on the above further beneficial effects, the circulating / cleaning pump is started, the sludge in the sludge gradient layer can enter the circulating / cleaning pump through the circulating sludge outlet, then enter the circulating sludge inlet through the circulating / cleaning pump, and finally enter the sludge distribution pipe through the circulating sludge inlet, the circulating sludge amount is adjusted through the valve and the pump frequency, and the circulating sludge flowmeter can measure the sludge flow entering the sludge distribution pipe.

[0025] Further, the sludge discharge port communicates with the inlet of the sludge discharge pump through a pipeline, the outlet of the sludge discharge pump communicates with the sludge discharge pipe, and a sludge discharge flowmeter is arranged on the sludge discharge pipe.

[0026] Further, the outlet of the circulating / cleaning pump communicates with the inlet of the sludge discharge pump through a pipeline.

[0027] Based on the above further beneficial effect is: in the outlet of circulating / descaling pump set branch pipeline to the sludge pump, while the pipeline circulation to the pipeline flushing, prevent the bottom scale, also can be used as flushing branch, can be adjusted according to the actual situation corresponding to the water pump and valve operating condition, prevent the effect of preventing pipe scale, to avoid the device after long time running blockage.

[0028] Further, the reactor is a cylindrical tower structure, and the height-diameter ratio of the reactor is 3-6:1. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 It is the structure diagram of the secondary sludge concentration device for high-hardness wastewater hardening sludge in the utility model;

[0030] Figure 2 It is the perspective view of the flow guide device in the utility model;

[0031] Figure 3 It is the sectional view of the flow guide device in the utility model;

[0032] Figure 4 It is the perspective view of the secondary sludge ripener in the utility model;

[0033] Figure 5 It is the sectional view of the secondary sludge ripener in the utility model.

[0034] In the drawings, the component list represented by each sign is as follows:

[0035] 1, reactor, 110, sludge gradient layer, 120, natural sedimentation layer, 130, sludge ripening layer, 140, ripening settlement layer, 150, clear water layer, 160, sludge discharge port, 170, supernatant outlet, 180, circulating sludge discharge port, 190, circulating sludge inlet, 2, sludge circulating device, 210, circulating / descaling pump, 220, circulating sludge flow meter, 3, flow guide device, 310, vertical flow guide cylinder, 311, water inlet, 320, diffusion cylinder, 330, reflecting plate, 340, connecting rod, 4, secondary sludge ripener, 410, outer separation cover, 420, inner separation cover, 430, split connecting piece, 440, sludge distribution pipe, 5, sludge pump, 6, sludge discharge pipe, 7, sludge discharge flow meter. DETAILED DESCRIPTION

[0036] The principles and characteristics of the utility model are described below in combination with the drawings, and the examples are only used to explain the utility model and not to limit the scope of the utility model.

[0037] Example 1

[0038] As Figures 1-5As shown, a sludge secondary concentration device for high-hardness wastewater hardness-removing sludge, comprising: a reactor 1 and a sludge circulating device 2, the reactor 1 is sequentially divided into a sludge gradient layer 110, a natural sedimentation layer 120, a sludge maturation layer 130, a maturation settling layer 140 and a clear water layer 150 from bottom to top, wherein the reactor 1 is provided with a sludge discharge port 160 at the bottom, which is used for subsequent sludge discharge in the reactor 1, and it is generally understood that a valve is arranged on the sludge discharge port 160, that is, when the sludge in the reactor 1 cannot be discharged through the sludge discharge port 160, only when the valve is opened, the sludge can be discharged through the sludge discharge port 160; the reactor 1 is arranged with a flow guide device 3 for feeding high-hardness wastewater into the natural sedimentation layer 120, the sludge maturation layer 130 is arranged with a sludge secondary maturation device 4, and the sludge circulating device 2 is used to feed sludge of a specified concentration in the sludge gradient layer 110 into the sludge secondary maturation device 4, and the concentration of the specified sludge is generally 12% to 18%;

[0039] The high-hardness wastewater is fed into the natural sedimentation layer 120 in the reactor 1 through the flow guide device 3, the hardness-removing sludge in the high-hardness wastewater enters the sludge maturation layer 130 after rectification in the natural sedimentation layer 120, is fully matured in the sludge secondary maturation device 4, enters the maturation settling layer 140 for secondary separation after maturation, the supernatant enters the clear water layer 150, the treated supernatant is discharged, and the settled sludge enters the sludge gradient layer 110, in addition, the sludge circulating device 2 feeds the sludge of a specified concentration in the sludge gradient layer 110 into the sludge secondary maturation device 4;

[0040] By layering the sludge gradient layer 110, the natural sedimentation layer 120, the sludge maturation layer 130, the maturation settling layer 140 and the clear water layer 150 in the reactor 1, the high-hardness wastewater is first fed into the natural sedimentation layer 120, and then passes through the sludge maturation layer 130, the high-hard sludge in the high-hardness wastewater is precipitated with the recycled sludge particle crystals of a suitable concentration in the sludge secondary maturation device 4 when passing through the sludge maturation layer 130, so as to strengthen the crystallization precipitation capacity of the system, accelerate the precipitation of the matured sludge crystal nucleus, speed up the formation of particles and flocs, and gradually compress the layered precipitation process by using the adsorption, bridging and net capture effect of the settled flocs, so as to achieve the effects of sludge and water separation and improvement of sludge solid content;

[0041] In the scheme, the combination of the sludge circulating device 2 and the sludge secondary maturation device 4 can make the sludge concentration system run more flexibly, improve the stability of the effluent water quality, and the sludge circulating device 2 circulates the sludge of the specified concentration in the sludge gradient layer 110, so that the sludge concentration in the system is maintained at a relatively constant value, and the low-concentration sludge newly entering the system is fully mixed, thereby improving the stability and impact load capacity of the system operation. The sludge circulating device 2 and the discharged sludge detection control reaction system can also be used to control the sludge crystallization process in the system, and the size, shape, concentration and crystal nucleus shape of the crystal can be controlled by temperature, pH and fluid flow rate.

[0042] The existing sludge gravity concentration equipment has poor concentration effect and poor effluent stability. The present application can realize secondary concentration of sludge, flexible operation of the equipment, stable effluent water quality, and obvious sludge reduction effect. In the process of secondary concentration and reduction of hard sludge for high-hardness wastewater, the present application has obvious advantages.

[0043] Example 2

[0044] As shown in Figure 1 , the present embodiment is a further improvement based on example 1, and the specific improvements are as follows:

[0045] The reactor 1 is provided with a supernatant outlet 170 corresponding to the clear water layer 150. The supernatant can be discharged through the supernatant outlet 170 in a self-flowing manner.

[0046] Example 3

[0047] As shown in Figure 1 , Figure 2 , Figure 3 , the present embodiment is a further improvement based on example 1 or 2, and the specific improvements are as follows:

[0048] The flow guide device 3 comprises a vertical flow guide cylinder 310, the upper end of which is above the water level of the clear water layer 150, and the lower end of which is connected with a diffusion cylinder 320, below which a reflecting plate 330 is arranged at a predetermined interval, the reflecting plate 330 is connected with the diffusion cylinder 320 through a plurality of connecting rods 340, the specific number of the connecting rods 340 can be one, two, three, four or other numbers, which are only exemplarily described herein, the gap between the reflecting plate 330 and the diffusion cylinder 320 forms a water outlet, the water outlet of the flow guide device 3 is in the natural sedimentation layer 120, the upper end of the vertical flow guide cylinder 310 is provided with a water inlet 311, the water inlet 311 penetrates to the outside of the reactor 1, the high-hardness wastewater enters the vertical flow guide cylinder 310 through the water inlet 311, then automatically falls by gravity, and then enters the diffusion cylinder 320, and then continues to fall, and then falls on the reflecting plate 330, and then spreads around by impact, and finally enters the natural sedimentation layer 120 from the gap between the reflecting plate 330 and the diffusion cylinder 320.

[0049] Embodiment 4

[0050] As shown in Figure 2 , Figure 3 , this embodiment is a further improvement on the basis of embodiment 3, and the specific improvements are as follows:

[0051] The diffusion cylinder 320 is a frustum, the small-diameter end of the diffusion cylinder 320 is connected with the lower end of the vertical flow guide cylinder 310, and the large-diameter end of the diffusion cylinder 320 is connected with the reflecting plate 330 through a plurality of connecting rods 340, the reflecting plate 330 is high in the middle and low at the periphery, which is beneficial to the spreading of the high-hardness wastewater to the periphery, and at the same time, the sludge can slide by gravity to avoid accumulation on the reflecting plate 330.

[0052] Embodiment 5

[0053] As shown in Figure 1 , Figure 4 , Figure 5 , this embodiment is a further improvement on the basis of embodiment 3 or 4, and the specific improvements are as follows:

[0054] The sludge secondary digester 4 comprises an outer separation cover 410 and an inner separation cover 420 arranged in the upper end port of the outer separation cover 410, the inner separation cover 420 is fixedly sleeved on the vertical flow guide cylinder 310 in the flow guide device 3, and a gap is formed between the inner separation cover 420 and the outer separation cover 410. The inner separation cover 420 is connected with the outer separation cover 410 through a plurality of split connectors 430, and the lower end of the inner separation cover 420 is peripherally arranged with a sludge distribution pipe 440, a plurality of sludge distribution holes are formed in the sludge distribution pipe 440, and the sludge circulating device 2 is used to send sludge of a specified concentration in the sludge gradient layer 110 into the sludge distribution pipe 440 in the sludge secondary digester 4. The sludge in the sludge distribution pipe 440 is sprayed out of the sludge distribution holes, the baffle design of the sludge secondary digester 4 can realize the solid-liquid separation effect, that is, the direction of the circulating sludge into the sludge is opposite to the direction of the conventional sludge flow, and the local reduction of the flow section (the gradually reduced flow space formed by the inner and outer separation covers) can achieve the effect of strengthening the sludge-water separation (the sludge particles in laminar flow are separated from the flow field after touching the separation cover, which is similar to the Hazen shallow sedimentation theory), and further intercepts the solid particles in the system.

[0055] Example 6

[0056] As shown in Figure 4 , Figure 5 , this embodiment is a further improvement based on example 5, as follows:

[0057] The outer separation cover 410 is in the shape of a truncated cone, the upper end of the outer separation cover 410 is a small-diameter end, and the lower end of the outer separation cover 410 is a large-diameter end. The inner separation cover 420 is in the shape of a truncated cone, the upper end of the inner separation cover 420 is a large-diameter end, and the lower end of the inner separation cover 420 is a small-diameter end.

[0058] Example 7

[0059] As shown in Figure 1 , this embodiment is a further improvement based on example 5, as follows:

[0060] The sludge circulation device 2 includes a circulation / descaling pump 210 and a circulating sludge flow meter 220. A circulating sludge outlet 180 is opened on the reactor 1 in the region corresponding to the sludge gradient layer 110. A circulating sludge inlet 190 is opened on the reactor 1 and connected to the sludge distribution pipe 440. The inlet of the circulation / descaling pump 210 is connected to the circulating sludge outlet 180 via a pipe, and the outlet of the circulation / descaling pump 210 is connected to the circulating sludge inlet 190 via a pipe. A circulating sludge flow meter 220 is installed on the pipeline between them. When the circulating / descaling pump 210 is started, the sludge in the sludge gradient layer 110 can enter the circulating / descaling pump 210 through the circulating sludge outlet 180, and then enter the circulating sludge inlet 190 through the circulating / descaling pump 210. Finally, it is sent into the sludge distribution pipe 440 through the circulating sludge inlet 190. The circulating sludge volume can be adjusted by the valve and pump frequency. The circulating sludge flow meter 220 can measure the sludge flow rate entering the sludge distribution pipe 440.

[0061] Furthermore, the sludge discharge port 160 is connected to the inlet of the sludge discharge pump 5 via a pipe, and the outlet of the sludge discharge pump 5 is connected to the sludge discharge pipe 6. The sludge discharge pipe 6 is equipped with a sludge discharge flow meter 7. When the sludge discharge pump 5 is started, the sludge in the reactor 1 can enter the sludge discharge pump 5 through the sludge discharge port 160, and then be sent into the sludge discharge pipe 6 by the sludge discharge pump 5. The sludge discharge flow meter 7 can measure the flow rate of the discharged sludge.

[0062] The outlet of the circulation / descaling pump 210 is connected to the inlet of the sludge pump 5 via a pipeline. A branch pipeline is set at the outlet of the circulation / descaling pump 210 to the sludge pump 5. While circulating in the pipeline, the pipeline is flushed to prevent scale buildup at the bottom. It can also be used as a flushing branch pipe. The operating conditions of the corresponding pumps and valves can be flexibly adjusted according to the actual situation to ensure the effect of preventing scale buildup in the pipeline and to prevent blockage after the device has been running for a long time.

[0063] Example 8

[0064] like Figure 1 As shown, this embodiment is a further improvement on any one of embodiments 1 to 7, as detailed below:

[0065] Reactor 1 has a cylindrical tower structure with a height-to-diameter ratio of 3 to 6:1. The bottom of reactor 1 is conical to facilitate the entry of sludge into the sludge discharge port 160.

[0066] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A sludge secondary concentration device for high hardness wastewater hardness removal sludge, characterized by, The application relates to a high-hardness wastewater treatment device, which comprises a reactor (1) and a sludge circulating device (2), the reactor (1) is sequentially divided into a sludge gradient layer (110), a natural precipitation layer (120), a sludge curing layer (130), a curing settlement layer (140) and a clear water layer (150) from bottom to top, a sludge discharge port (160) is arranged at the bottom of the reactor (1), a flow guide device (3) for feeding high-hardness wastewater into the natural precipitation layer (120) is arranged in the reactor (1), a sludge secondary curing device (4) is arranged in the sludge curing layer (130), and the sludge circulating device (2) is used for feeding sludge with a specified concentration in the sludge gradient layer (110) into the sludge secondary curing device (4). An upper clear liquid outlet (170) is arranged on the reactor (1) and corresponds to the clear water layer (150).

2. A sludge secondary concentration device for hardening sludge of high hardness of wastewater hardness removal according to claim 1, characterized in that, The flow guide device (3) comprises a vertical flow guide cylinder (310), the upper end of the vertical flow guide cylinder (310) is above the liquid surface line of the clear water layer (150), the lower end of the vertical flow guide cylinder (310) is connected with a diffusion cylinder (320), a reflection plate (330) is arranged below the diffusion cylinder (320) at a predetermined interval, the reflection plate (330) is connected with the diffusion cylinder (320) through a plurality of connecting rods (340), the gap between the reflection plate (330) and the diffusion cylinder (320) forms a water outlet, the water outlet is arranged in the natural precipitation layer (120), and the upper end of the vertical flow guide cylinder (310) is provided with a water inlet (311) which penetrates out of the reactor (1).

3. A secondary sludge concentration device for hardening sludge of high hardness wastewater according to claim 2, characterized in that, The diffusion cylinder (320) is in the shape of a truncated cone, the small-diameter end of the diffusion cylinder (320) is connected with the lower end of the vertical flow guide cylinder (310), the large-diameter end of the diffusion cylinder (320) is connected with the reflection plate (330) through a plurality of connecting rods (340), and the reflection plate (330) is high in the middle and low at the periphery.

4. A secondary sludge concentration device for hardening sludge of high hardness according to claim 3, characterized in that, The sludge secondary curing device (4) comprises an outer separation cover (410) and an inner separation cover (420), the inner separation cover (420) is arranged in the upper end port of the outer separation cover (410), the inner separation cover (420) is fixedly sleeved on the vertical flow guide cylinder (310) in the flow guide device (3), the inner separation cover (420) and the outer separation cover (410) have a gap, the inner separation cover (420) is connected with the outer separation cover (410) through a plurality of split connecting pieces (430), the lower end of the inner separation cover (420) is peripherally arranged with a sludge distribution pipe (440), a plurality of sludge distribution holes are arranged on the sludge distribution pipe (440), and the sludge circulating device (2) is used for feeding sludge with a specified concentration in the sludge gradient layer (110) into the sludge distribution pipe (440) in the sludge secondary curing device (4).

5. A secondary sludge concentration device for hardening sludge of high hardness according to claim 3, characterized in that, The outer separation cover (410) is in the shape of a truncated cone, the upper end of the outer separation cover (410) is a small-diameter end, the lower end of the outer separation cover (410) is a large-diameter end, the inner separation cover (420) is in the shape of a truncated cone, the upper end of the inner separation cover (420) is a large-diameter end, and the lower end of the inner separation cover (420) is a small-diameter end.

6. A secondary sludge concentration device for hardening sludge of high hardness according to claim 5, wherein ​ 7. A secondary sludge concentration device for hardening sludge of high hardness according to claim 5, characterized in that, The sludge circulating device (2) comprises a circulating / descaling pump (210) and a circulating sludge flowmeter (220), a circulating sludge outlet (180) is arranged on the reactor (1) at the area corresponding to the sludge gradient layer (110), a circulating sludge inlet (190) is arranged on the reactor (1) and communicates with the sludge distribution pipe (440), the inlet of the circulating / descaling pump (210) communicates with the circulating sludge outlet (180) through a pipeline, the outlet of the circulating / descaling pump (210) communicates with the circulating sludge inlet (190) through a pipeline, and the pipeline between the outlet of the circulating / descaling pump (210) and the circulating sludge inlet (190) is provided with the circulating sludge flowmeter (220).

8. A sludge secondary concentration device for hardening sludge of high hardness of wastewater hardness removal according to claim 7, characterized in that, The sludge discharge port (160) communicates with the inlet of the sludge discharge pump (5) through a pipeline, the outlet of the sludge discharge pump (5) communicates with the sludge discharge pipe (6), and the sludge discharge pipe (6) is provided with a sludge discharge flowmeter (7).

9. A secondary sludge concentration device for hardening sludge of high hardness according to claim 8, characterized in that, The outlet of the circulating / descaling pump (210) communicates with the inlet of the sludge discharge pump (5) through a pipeline.

10. The secondary sludge concentration device for hardening sludge of high hardness in wastewater according to any one of claims 1 to 9, characterized by, The reactor (1) is a cylindrical tower body structure, the height-diameter ratio of the reactor (1) is 3-6:1, and the bottom of the reactor (1) is in a conical shape.

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