Fluidized bed reaction device for sulfur autotrophic nitrogen and phosphorus removal

Abstract

The utility model discloses a fluidized bed reaction device for sulfur autotrophic nitrogen and phosphorus removal, which relates to the technical field of sewage treatment and is characterized in that a water inlet pipe and a water outlet pipe are respectively communicated from the bottom to the bottom of the side wall and from the top of the side wall of a barrel; the clean water area, the settling area, the fluidization area and the raking mechanism are sequentially formed by dividing the interior of the device from top to bottom through a filter layer structure covering the cross section and a water distributor; and two ends of the circulating pipeline are respectively communicated with the water distributor and the bottom of the clear water area. Denitrification microorganisms, sulfur autotrophic electron donors and floc particles of the sulfur autotrophic electron donors in the fluidization area are kept in a suspended state, so that the electron transfer efficiency and the denitrification reaction rate between microorganisms and solid reduced sulfur can be improved; and the filter layer structure filters suspended matters in the liquid to form a sinking filter cake at the bottom of the filter layer structure by utilizing the upward flowing movement of the liquid, so that the loss of denitrification microorganisms and sulfur autotrophic electron donors is avoided, the effluent turbidity is ensured, and the sludge concentration and denitrification efficiency in the fluidization area are also ensured.

Description

Technical Field

[0001] The utility model relates to the technical field of sewage treatment, in particular to a fluidized bed reaction device and method for deep denitrification and dephosphorization of sewage in a sewage treatment plant. Background Art

[0002] Nitrogen and phosphorus are the main elements that cause eutrophication of water bodies. Phosphorus in domestic sewage mainly relies on microbial treatment, but the total phosphorus concentration of secondary treated effluent is stable at around 0.5-1 mg / L, which is difficult to reach the higher requirement of 0.2 mg / mL. Deep phosphorus removal from sewage generally adopts the method of adding iron salts and aluminum salts to sewage to form iron phosphate and aluminum phosphate compound precipitation, and then removes the iron phosphate and aluminum phosphate compound precipitation in sewage by sand filtration, coagulation magnetic separation and other methods.

[0003] In the prior art, the removal of nitrogen from domestic sewage generally adopts the nitrification-heterotrophic denitrification process technology, which uses aerobic biological metabolism to convert organic nitrogen and ammonia nitrogen in the water into nitrate nitrogen, and then returns the sewage to the anoxic tank to use the organic matter in the sewage as an electron donor through heterotrophic denitrification microorganisms to convert nitrate nitrogen into nitrogen gas. The return denitrification denitrification technology also encounters some obstacles in meeting the increasingly stringent drainage total nitrogen water quality standards: first, a very high return ratio is required to make the total nitrogen meet the discharge standard, resulting in excessive energy consumption for water treatment and uneconomical; second, the carbon-nitrogen ratio of domestic sewage is generally too low, which cannot meet the demand for organic carbon for heterotrophic denitrification denitrification.

[0004] In order to further improve the nitrogen removal effect of sewage, adding an anaerobic biofilter after the secondary sedimentation tank and adding organic carbon to the biofilter to rely on heterotrophic denitrifying bacteria to remove nitrogen is currently a common treatment method. However, the addition of agents such as sodium acetate leads to excessively high denitrification costs, and inadequate metering control during the addition process will also lead to excessively high effluent COD, resulting in secondary pollution problems.

[0005] In order to make up for the shortcomings of heterotrophic denitrification and meet the needs of deep denitrification in water treatment, sulfur autotrophic denitrification technology has been rapidly developed as a representative autotrophic denitrification technology in recent years. Sulfur autotrophic denitrification is a process in which facultative anaerobic microorganisms such as denitrifying thiobacillus use inorganic carbon as a carbon source to complete anabolism, and use sulfur and reducing sulfur compounds such as thiosulfate, sulfite, sulfide, etc. as electron donors to reduce nitrate to nitrogen gas. Among them, sulfur and iron sulfide as electron donors are the mainstream direction of development for denitrification. Sulfur autotrophic denitrification has the advantages of abundant and cheap sulfur resources, low sludge production, and low treatment costs. In the process of autotrophic denitrification with sulfur as an electron donor, water acidification will occur. Carbonates such as limestone are usually used as a medium to stabilize the pH of the system. The existing sulfur-limestone autotrophic denitrification system is to mix limestone and elemental sulfur particles in a certain proportion as fillers, and load them into the reaction filter column for sewage treatment. Limestone neutralizes and reduces sulfur oxidation to produce acid, thereby buffering and stabilizing the pH of the system.

[0006] However, in the prior art, the sulfur autotrophic denitrification deep denitrification and phosphorus removal technology has the following outstanding problems:

[0007] First, the problem of granulation of sulfur autotrophic materials. The current sulfur autotrophic denitrification technology uses the quartz sand deep bed filter process. First, the sulfur autotrophic denitrification material needs to be granulated into 2-6mm particles and filled into the anaerobic denitrification filter. Sulfur autotrophic composite filter materials generally use melt granulation, which requires special sulfur composite and melt granulation equipment, especially for sulfur raw materials with high water content, such as sulfur paste. Melt granulation first requires drying and dehydration, or steam heating in the molten sulfur tank to separate sulfur and water. The granulation process will inevitably greatly increase the processing cost of sulfur autotrophic materials.

[0008] Second, the problem of blockage and backwashing of the autotrophic denitrification filter. During the operation of the filter, the gaps between the filter particles will be blocked due to biofilm growth, suspended matter interception in the water, disintegration and pulverization of the sulfur autotrophic denitrification filter, and accumulation of fine particles of inert matter in the filter. When the water flow rate is reduced to a certain level, it is necessary to remove the fine particles accumulated in the gaps between the filter particles by backwashing. However, the backwashing process not only washes out the fine particles that cause blockage, but also causes the biofilm to fall off. The autotrophic biological value-added cycle is long, and the biofilm recovers slowly, requiring a certain period of time, which affects the effluent water quality in the biofilm recovery stage. In addition, sulfur and its composite materials have low particle density and low strength, which are greatly different from the density and strength of carbonate minerals. Backwashing can easily cause sulfur particles to wear and increase loss, and can also cause sulfur particles to separate from carbonate particles.

[0009] Third, the autotrophic denitrification filter needs to be denitrified. The nitrogen generated during the sulfur autotrophic denitrification process is adsorbed on the surface of the sulfur autotrophic granular filter material. The bubbles that are difficult to discharge gather in the filter layer, causing air blockage, affecting the operation of the filter, and requiring regular nitrogen denitrification.

[0010] Fourth, the existing fluidized bed reactor is difficult to completely separate suspended matter by relying solely on sedimentation, which not only causes the loss of autotrophic microorganisms and reduces the concentration of autotrophic microorganisms in the fluidized bed reactor, but also causes the loss of fine-grained sulfur autotrophic materials. It is not suitable for denitrification of slurry-like fine-grained sulfur autotrophic materials such as sulfur paste. Utility Model Content

[0011] The utility model is provided with the name of utility model just to avoid the deficiencies existing in the above-mentioned prior art.

[0012] The utility model adopts the following technical scheme to solve the technical problem: a fluidized bed reaction device for sulfur autotrophic denitrification and dephosphorization, comprising a cylinder with a cavity inside, the bottom of the cylinder is connected to the bottom of the side wall and the top of the side wall respectively with a water inlet pipe and a water outlet pipe, including a clear water area, a sedimentation area and a fluidization area separated by a filter layer structure and a water distributor arranged in the cavity from top to bottom in sequence to form a covering cross section, and a raking mechanism;

[0013] A circulation pipeline is also provided, with two ends respectively connected to the water distributor and the bottom of the clean water area, and a water pump is connected to the circulation pipeline;

[0014] The filter layer structure is filled with low-density porous medium filter material, and the raking mechanism is used to rake the filter material.

[0015] Preferably, it also includes a central tube;

[0016] The center of the filter layer structure is provided with a central pipe which is connected with the sedimentation area and extends upward to the top of the clean water area. The central pipe is fixedly connected with the filter layer structure as a whole.

[0017] Preferably, the water distributor comprises a circulating water inlet, a circular pipe and a water distribution branch pipe;

[0018] The circular tube is an annular tubular structure, and each water distribution branch pipe is arranged in the annular structure of the circular tube, and both ends are respectively connected to the circular tube; the circular tube is provided with the circulating water inlet connected to the circulating pipeline, and the top and both sides of the water distribution branch pipe are densely provided with holes.

[0019] Preferably, it further comprises a mud discharge pipe, a backwash discharge pipe and a backwash water inlet pipe, and the water distributor is further provided with a backwash water inlet located on the opposite side of the circulating water inlet, and the backwash water inlet is connected to the backwash water inlet pipe;

[0020] A mud discharge pipe is provided at the bottom of the side wall of the cylinder on the opposite side of the water inlet pipe, and the backwash discharge pipe is connected in parallel with the water outlet pipe to the top of the side wall of the cylinder.

[0021] Preferably, it also includes a stirring mechanism, wherein the stirring mechanism includes a stirring driving machine, a stirring shaft, a stirring blade and a limiting end;

[0022] The stirring shaft extends from top to bottom through the central tube to the bottom of the fluidized zone, the top end of which is fixedly connected to the output end of the fixedly installed stirring driving machine, and the bottom end is fixedly installed to the stirring blade; a gap is left between the stirring shaft and the central tube;

[0023] The bottom of the stirring blade is provided with a downwardly convex limiting end at the extended line of the axis of the stirring shaft, and the bottom of the cylinder body is correspondingly provided with a limiting cylinder matched with the limiting end;

[0024] The limiting end is inserted into the limiting cylinder and is used for limiting the lower end of the stirring shaft.

[0025] Preferably, the raking mechanism comprises raking teeth, a raking rod, a rotating beam, end rollers and an axle clamp;

[0026] The top end of the rake rod is fixedly connected to the rotating beam, and the bottom end is fixedly provided with rake teeth in a row, each extending into the filter material;

[0027] The stirring shaft is arranged to penetrate the rotating beam, and a rotating pair is formed between the two to support the two to rotate relative to each other around the axis of the stirring shaft;

[0028] An end roller is rotatably mounted at each of the two ends of the rotating beam, and the end roller is mounted to the top of the upper end surface of the cylinder, and the outer side thereof is a limit edge structure convex outward in the radial direction; the limit edge structure is clamped on the outer side of the cylinder, and together with the stirring shaft, limits the relative position of the rotating beam and the end roller and the cylinder;

[0029] The outer ring and the inner ring of the shaft clamp are respectively fixed to the rotating beam and the stirring shaft, and when the shaft clamp is tightened, the outer ring and the inner ring are locked to limit the relative rotation of the stirring shaft and the rotating beam.

[0030] Preferably, it also includes a baffle;

[0031] A baffle plate is provided above the top opening of the central tube, which shields the central tube and leaves a gap between the baffle plate and the top end of the central tube.

[0032] Preferably, the filter layer structure comprises a support structure, a filter layer and the filter material;

[0033] The filter layer is a warehouse structure with a mesh bottom plate, and the filter material is filled in the filter layer;

[0034] The bottom of the filter layer is fixedly mounted with a triangular rib-shaped support structure, which is fixedly mounted on the cylinder body and is used to support the filter layer.

[0035] Preferably, an overflow water weir groove fixedly mounted on the cylinder body is provided in the cylinder body above the filter layer structure, and the water outlet pipe is connected with the clean water area through the overflow water weir groove;

[0036] It also includes a dosing pipe; one end of the circulation pipeline, the dosing pipe and the water inlet pipe are connected in parallel and fixed to the bottom of the side wall of the cylinder, and are connected to the fluidization zone.

[0037] A fluidized bed reaction method for sulfur autotrophic denitrification and phosphorus removal, using the above-mentioned fluidized bed reaction device for sulfur autotrophic denitrification and phosphorus removal to carry out deep denitrification and phosphorus removal treatment of sewage, comprising the following steps:

[0038] The first step is to prepare the autotrophic denitrification and dephosphorization agent in powder, slurry or paste form into an autotrophic denitrification and dephosphorization suspension with a mass concentration of 0.5-10%, store it in a dosing tank, and stir it continuously to keep the autotrophic denitrification and dephosphorization suspension stable to prevent the precipitation of particles;

[0039] In the second step, 0.1-10% of the volume of the treated sludge obtained from the domestic sewage treatment plant is added into the cylinder as a source of microbial strains;

[0040] The third step is to control the valve of the water inlet pipe to open, and add the sulfur autotrophic denitrification and dephosphorization agent suspension obtained in the first step to the water inlet pipe of the reaction device through the dosing pipe according to the reaction equivalent ratio of nitrate nitrogen to autotrophic electron donor in water of 1:1-1.5, and add it continuously or intermittently, mix it with the wastewater and then enter the denitrification and dephosphorization reactor, and the metering flow rate is controlled according to the preset hydraulic retention time;

[0041] Subsequently, the stirring drive and the water pump are started; the stirring drive drives the stirring blades to rotate via the stirring shaft, and the water pump drives the circulation of the mixed liquid, so that the autotrophic denitrification and dephosphorization agent and the microorganisms including the autotrophic denitrification bacteria are kept in a suspended state in the fluidized area, and the denitrification microorganisms in the inoculated microorganisms use electron donors to convert the nitrate nitrogen in the mixed liquid into nitrogen gas and discharge it out of the cylinder through the central tube, and at the same time, the biomineralization action converts the dissolved phosphate into solid iron phosphorus and calcium phosphorus precipitation;

[0042] In the fourth step, the rising suspension in the fluidized zone is separated into sinking particles and clarified liquid by settling in the settling zone. The clarified liquid passes through the filter layer to produce clear water. In the process of the clarified liquid passing through the filter layer, a microbial film is formed on the surface of the filter material particles. The fine particles including free microorganisms in the clarified liquid are retained by the filter layer. The clear water passing through the filter layer is the treated wastewater, which is discharged out of the cylinder through the overflow weir and the outlet pipe in sequence.

[0043] Step 5: In the initial stage of the fluidized bed reaction device, the opening of the valve at the water inlet pipe is gradually increased to gradually increase the liquid inlet flow rate, so that the hydraulic retention time is gradually shortened until the fluidized bed reaction device is stably operated;

[0044] Step 6: During the stable operation of the fluidized bed reaction device, if the liquid level in the central tube rises to a preset warning liquid level, the valves at the water inlet pipe, the dosing pipe, and the water outlet pipe are closed, the water pump is stopped, the valve at the backwash water inlet pipe is opened, the valve at the backwash discharge pipe is opened, the backwash water pump is started, and at the same time, the speed of the stirring shaft is reduced;

[0045] At this time, the backwash water flows into the water distributor from the backwash water inlet through the backwash water inlet pipe under the action of the backwash water pump, and then is distributed to each water distribution branch pipe through the circular pipe, flows upward from each hole of each water distribution branch pipe, backwashes the filter layer, and then flows upward, overflows and is discharged to the backwash discharge pipe through the overflow water weir groove;

[0046] At the same time, the shaft holder of the raking mechanism holds the stirring shaft tightly, and drives the rake teeth to rotate with the axis of the stirring shaft as the rotating axis through the rotating beam and the rake rod, so as to rake the filter particles, discharge the bubbles accumulated between the filter particles, make the filter particles accumulate again, and recreate the gaps between the filter particles to restore the permeability of the filter layer;

[0047] After the rake teeth rotate one circle with the axis of the stirring shaft as the rotating axis, the liquid level in the central tube is reduced to within cm of the liquid level outside the central tube, and the filtering function of the filter layer is fully restored;

[0048] Then shut down the backwash water pump, close the valves at the backwash water inlet pipe and the backwash discharge pipe, release the shaft clamp, open the valves at the water inlet pipe, dosing pipe and outlet pipe, start the water pump, and continue the normal treatment of wastewater.

[0049] The utility model provides a fluidized bed reaction device for sulfur autotrophic denitrification and phosphorus removal, which can prepare a suspension with powdery, semi-solid, slurry, or paste-like sulfur-rich raw materials as an electron donor for wastewater denitrification and phosphorus removal, thereby realizing direct addition of a high-water-content, low-cost sulfur electron donor to a water treatment reactor for denitrification and phosphorus removal, and solving the problem of interception of microorganisms and sulfur electron donor particles in a fluidized bed reactor, and has the following beneficial effects:

[0050] 1. The water distribution pipe and filter layer structure of the utility model naturally separate the volume cavity of the cylinder into a clear water area, a sedimentation area and a clear water area. The denitrification microorganisms, sulfur autotrophic electron donors and floc particles in the fluidized area are kept in a suspended state, which is helpful to improve the electron transfer efficiency between microorganisms and solid sulfur reduction and the denitrification reaction rate; most of the suspended matter in the sedimentation area is settled in the fluidized area, reducing the load of suspended matter intercepted by the filter layer and the clogging effect, and extending the backwashing cycle; the filter layer structure utilizes the upward movement of the liquid to filter the suspended matter in the liquid to form a filter cake at the bottom of the filter layer structure, and the filter cake settles to the fluidized area under the action of gravity, avoiding the loss of denitrification microorganisms and sulfur autotrophic electron donors, ensuring both the turbidity of the effluent and the sludge concentration and denitrification efficiency in the fluidized area.

[0051] 2. The filter layer structure of the utility model is filled with low-density porous medium filter material, which reduces the stacking density, support structure load and backwashing intensity; under the same particle size, the lower the density of the filter material particles, the lower the backwashing intensity required to expand the filter layer, the shorter the time for washing and removing the suspended matter trapped in the filter layer, and the lower the water consumption.

[0052] 3. The raking mechanism of the utility model raks the filter material through a push-mill circular motion, so as to discharge the bubbles accumulated in the filter material layer, realize the nitrogen expulsion of the filter material in the filter layer structure, loosen the filter material layer at the same time, re-create the gaps between the granules, reduce the clogging effect of the filter layer, extend the backwashing cycle, and improve the denitrification treatment effect.

[0053] 4. The surface of the filter material in the filter layer structure of the utility model is attached with autotrophic, heterotrophic denitrification and other microbial membranes, and the sulfur autotrophic electron donor particles and microorganisms are intercepted between the filter material particles. Complex microbial metabolism occurs in the filter layer structure, and the autotrophic and heterotrophic synergistic deep denitrification effect of the fixed filter bed is exerted.

[0054] 5. The setting of the central tube of the utility model avoids the formation of joints between the filter structure and the filter structure when the stirring mechanism is set, resulting in the rising water flow directly short-circuiting at the joint, so as to force the water flow to penetrate through the filter material layer and ensure the effective function of the filter material structure; at the same time, the gap between the stirring shaft and the central tube provides an escape channel for the nitrogen generated by denitrification and denitrification; in addition, the top of the central tube is higher than the height of the filter layer structure. The height difference uses air pressure to provide hydraulic loss compensation for the normal filtering water flow of the filter layer structure, which helps to extend the backwashing cycle, thereby avoiding backwashing from destroying the stability of the anaerobic denitrification system and improving the stability and efficiency of deep sewage treatment.

[0055] 6. The stirring mechanism of the utility model not only realizes better suspension of microorganisms and sulfur autotrophic electron donor particles in the fluidized zone, but also prevents coarse sulfur autotrophic electron donor particles from being deposited at the bottom of the suspension zone for a long time, affecting water inlet and clogging the sewage outlet, and also has the function of strengthening the grinding and refinement of coarse sulfur autotrophic electron donor particles.

[0056] 7. During the backwashing process of the reactor, the baffle of the utility model reflects the water flow sprayed from the top opening of the central tube downward, uses the reflected water flow to wash the filter material layer, and promotes the outflow of the suspended matter separated from the filter material, which is beneficial to the improvement of the backwashing effect and the improvement of the backwashing efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 This is a schematic diagram of the main structure of the utility model;

[0058] Figure 2 This is a schematic diagram of the top view of the water distributor of the utility model;

[0059] Figure 3 It is a cross-sectional structural schematic diagram of the raking mechanism of the utility model.

[0060] In the figure:

[0061] 1. Cylinder, 1-1, water inlet pipe, 1-2, water outlet pipe, 1-3, mud discharge pipe, 1-4, backwash water inlet pipe, 1-5, backwash discharge pipe, 1-6, dosing pipe, 1-7, circulation pipeline, 1-8, water pump, 1-9, limit cylinder, 1-10, overflow water weir, 1-11, baffle; 2, fluidization zone; 3, sedimentation zone; 4, filter layer structure, 4-1, support structure, 4-2, filter layer, 4-3, filter material; 5 , clean water area; 6, raking mechanism, 6-1, rake teeth, 6-2, rake rod, 6-3, rotating beam, 6-4, end roller, 6-5, shaft holder; 7, water distributor, 7-1, backwash water inlet, 7-2, circulation water inlet, 7-3, water distribution branch pipe, 7-4, round pipe, 7-5, hole; 8, stirring mechanism, 8-1, stirring drive motor, 8-2, stirring shaft, 8-3, stirring blade, 8-4, limit end, 9, center pipe. DETAILED DESCRIPTION

[0062] In order to make the purpose, technical solution and advantages of the embodiments of the utility model clearer, the technical solution in the embodiments of the utility model will be clearly and completely described below in combination with the embodiments of the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0063] A fluidized bed reaction device for sulfur autotrophic nitrogen and phosphorus removal, such as Figure 1~Figure 3As shown, the structural relationship is as follows: it includes a cylinder 1 with a cavity inside, the bottom of the cylinder 1 is connected to the bottom of the side wall and the top of the side wall respectively with an inlet pipe 1-1 and an outlet pipe 1-2, including a clean water area 5, a sedimentation area 3 and a fluidization area 2 and a raking mechanism 6 formed by the filter layer structure 4 and the water distributor 7 arranged in the cavity from top to bottom in sequence to cover the cross section;

[0064] A circulation pipeline 1-7 is also provided, with two ends connected to the water distributor 7 and the bottom of the clean water area 5 respectively, and a water pump 1-8 is provided on the circulation pipeline 1-7, which serves as a power source for liquid flow, microbial flocs and electron donor particle suspension;

[0065] The filter layer structure 4 is filled with low-density porous medium filter material 4 - 3 , and the raking mechanism 6 is used to rake the filter material.

[0066] In actual setting, the water inlet pipe 1-1 and the water outlet pipe 1-2 can be provided with water inlet pipe valves and water outlet pipe valves according to actual needs;

[0067] Filter material 4-3 has a density of 1.1-2.2 mm / cm 3 , porous granular materials with a particle size of 1-10 mm, including but not limited to high-density expanded perlite, water-quenched steel slag, granular activated carbon, low-density ceramsite, zeolite rock particles, porous ceramics, foamed basalt, and aerated concrete particles;

[0068] Preferably, the filter material 4-3 can be prepared by the following method: crushing, rolling and screening diatom shale to obtain sub-angular particles with a particle size of 3-5 mm, calcining at 500-1000°C to obtain a particle size of 1.2-1.5 g / cm 3 Porous, water-resistant granular filter material 4-3.

[0069] Preferably, it also includes a central tube 9;

[0070] A central pipe 9 is provided at the center of the filter layer structure 4 , which is connected with the sedimentation area 3 and extends upward to above the clean water area 5 . The central pipe 9 is fixedly connected to the filter layer structure 4 as a whole.

[0071] The central tube 9 is used to discharge the nitrogen generated by denitrification.

[0072] Preferably, the water distributor 7 includes a circulating water inlet 7-2, a circular pipe 7-4 and a water distribution branch pipe 7-3;

[0073] The circular tube 7-4 is an annular tubular structure, and each water distribution branch pipe 7-3 is arranged in the annular structure of the circular tube 7-4, and both ends are connected to the circular tube 7-4 respectively; a circulating water inlet 7-2 connected to the circulating pipeline 1-7 is opened on the circular tube 7-4, and holes 7-5 are densely opened on the top and both sides of the water distribution branch pipe 7-3.

[0074] In actual setting, the diameter of hole 7-5 can be 1-10 mm, and the distance between adjacent holes can be 50-200 mm.

[0075] Preferably, it also includes a mud discharge pipe 1-3, a backwash discharge pipe 1-5 and a backwash water inlet pipe 1-4, and the water distributor 7 is also provided with a backwash water inlet 7-1 located on the opposite side of the circulating water inlet 7-2, and the backwash water inlet 7-1 is connected to the backwash water inlet pipe 1-4;

[0076] A mud discharge pipe 1 - 3 is provided at the bottom of the side wall of the cylinder 1 on the opposite side of the water inlet pipe 1 - 1 , and a backwash discharge pipe 1 - 5 is connected in parallel with the water outlet pipe 1 - 2 to the top of the side wall of the cylinder 1 .

[0077] Preferably, it further comprises a stirring mechanism 8, wherein the stirring mechanism 8 comprises a stirring driving machine 8-1, a stirring shaft 8-2, a stirring blade 8-3 and a limiting end 8-4;

[0078] The stirring shaft 8-2 extends from top to bottom through the central tube 9 to the bottom of the fluidized zone 2, the top end of which is fixedly connected to the output end of the fixedly installed stirring driving machine 8-1, and the bottom end is fixedly installed to the stirring blade 8-3; a gap is left between the stirring shaft 8-2 and the central tube 9;

[0079] In actual setting, the inner diameter of the central tube 9 is preferably 2-10 cm larger than the outer diameter of the stirring shaft 8-2;

[0080] A downward convex limit end 8-4 is provided at the bottom of the stirring blade 8-3 at the extended line of the axis of the stirring shaft 8-2, and a limit cylinder 1-9 matching with the limit end 8-4 is provided at the bottom of the cylinder body 1;

[0081] The limiting end 8-4 is inserted into the limiting cylinder 1-9 to limit the lower end of the stirring shaft 8-2.

[0082] Preferably, the raking mechanism 6 includes rake teeth 6-1, a rake rod 6-2, a rotating beam 6-3, an end roller 6-4 and a shaft clamp 6-5;

[0083] The top of the rake rod 6-2 is fixedly connected to the rotating beam 6-3, and the bottom is fixedly provided with rake teeth 6-1 in a row, each extending into the filter material 4-3;

[0084] The stirring shaft 8-2 is arranged to penetrate the rotating beam 6-3, and a rotating pair is formed between the two to support the relative rotation of the two around the axis of the stirring shaft 8-2;

[0085] An end roller 6-4 is rotatably mounted at each end of the rotating beam 6-3. The end roller 6-4 is mounted to the top of the upper end surface of the cylinder 1, and its outer side is a radially outwardly convex limit edge structure; the limit edge structure is clamped on the outer side of the cylinder 1, and together with the stirring shaft 8-2, limits the relative position of the rotating beam 6-3 and the end roller 6-4 and the cylinder 1;

[0086] The outer ring and inner ring of the shaft holder 6-5 are respectively fixed to the rotating beam 6-3 and the stirring shaft 8-2, and when the shaft holder 6-5 is clamped, the outer ring and the inner ring are locked to limit the relative rotation of the stirring shaft 8-2 and the rotating beam 6-3.

[0087] In actual setting, the shaft clamp 6-5 can be an electromagnetic shaft clamp.

[0088] Preferably, it also includes a baffle 1-11;

[0089] A baffle 1 - 11 is provided above the top opening of the central tube 9 , shielding the central tube 9 and leaving a gap between the baffle 1 - 11 and the top of the central tube 9 .

[0090] In actual configuration, the baffles 1-11 may be configured as a conical cylindrical structure with increasing diameter from top to bottom;

[0091] When the reactor is provided with a stirring mechanism, the baffle 1-11 can prevent the backwash water from directly spraying upward from the top opening of the central tube 9 and causing the stirring drive motor 81 to get wet; at this time, the baffle 1-11 can also be installed and fixed to the stirring shaft 82.

[0092] Preferably, the filter layer structure 4 includes a support structure 4-1, a filter layer 4-2 and a filter material 4-3;

[0093] The filter layer 4-2 is a warehouse structure with a mesh bottom plate, and the filter material 4-3 is filled in the filter layer 4-2;

[0094] A triangular rib-shaped support structure 4-1 is fixedly installed at the bottom of the filter layer 4-2. The support structure 4-1 is fixedly installed on the cylinder 1 to support the filter layer 4-2.

[0095] In actual configuration, the thickness of the filter material 4-3 is preferably 20-50 cm, and the support structure 41 can be made of steel material;

[0096] Preferably, an overflow water weir 1-10 fixedly mounted on the cylinder 1 is provided above the filter layer structure 4 in the cylinder 1, and the outlet pipe 1-2 is connected to the clean water area 5 through the overflow water weir 1-10;

[0097] When the outlet pipe 1-2 is connected to the clean water area 5 through the overflow outlet weir trough 1-10, the backwash discharge pipe 1-5 can also be arranged in parallel with the outlet pipe 1-2 and connected to the clean water area 5 through the overflow outlet weir trough 1-10;

[0098] It also includes a dosing pipe 1-6; one end of the circulation pipeline 1-7, the dosing pipe 1-6 and the water inlet pipe 1-1 are connected in parallel and fixed to the bottom of the side wall of the cylinder 1, and are connected to the fluidization zone 2.

[0099] A fluidized bed reaction method for sulfur autotrophic denitrification and phosphorus removal, using the above-mentioned fluidized bed reaction device for sulfur autotrophic denitrification and phosphorus removal to carry out deep denitrification and phosphorus removal treatment of sewage, comprising the following steps:

[0100] The first step is to prepare the autotrophic denitrification and dephosphorization agent in powder, slurry or paste form into an autotrophic denitrification and dephosphorization suspension with a mass concentration of 0.5-10%, store it in a dosing tank, and stir it continuously to keep the autotrophic denitrification and dephosphorization suspension stable to prevent the precipitation of particles;

[0101] Sulfur autotrophic nitrogen and phosphorus removal agent can be in powder, semi-solid, slurry, paste form, and is mainly composed of sulfur, soluble sulfide and polysulfide, iron and manganese sulfide, and carbonate minerals;

[0102] In the second step, 0.1-10% of the volume of the treated sludge obtained from the domestic sewage treatment plant is added into the cylinder 1 as a source of microbial strains;

[0103] The third step is to control the valve of the water inlet pipe 1-1 to be opened, and the sulfur autotrophic denitrification and dephosphorization agent suspension obtained in the first step is metered, continuously or intermittently added to the water inlet pipe 1-1 of the reaction device through the dosing pipe 1-6 according to the reaction equivalent ratio of nitrate nitrogen to autotrophic electron donor in water of 1:1-1.5, and then mixed with the wastewater and enter the denitrification and dephosphorization reactor, and the metered flow rate is controlled according to the preset hydraulic retention time;

[0104] In actual operation, the hydraulic retention time can be preferably preset to 6h;

[0105] Subsequently, the stirring drive 8-1 and the water pump 1-8 are started; the stirring drive 8-1 drives the stirring blade 8-3 to rotate via the stirring shaft 8-2, and the water pump 1-8 drives the circulation of the mixed liquid, so that the autotrophic denitrification and dephosphorization agent and the microorganisms including the autotrophic denitrification bacteria are kept in a suspended state in the fluidized area 2, and the denitrification microorganisms in the inoculated microorganisms use electron donors to convert the nitrate nitrogen in the mixed liquid into nitrogen gas and discharge it to the outside of the cylinder 1 through the central tube 9. At the same time, the biomineralization action converts the dissolved phosphate into solid iron phosphorus and calcium phosphorus precipitation;

[0106] The rising suspension in the fluidized zone is separated into sinking particles and clarified liquid by settling in the settling zone 3. The clarified liquid passes through the filter layer 4-2 to produce clear water. During the process of the clarified liquid passing through the filter layer 4-2, a microbial film is formed on the surface of the filter particles. The fine particles including free microorganisms in the clarified liquid are retained by the filter layer 4-2. The clear water passing through the filter layer is the treated wastewater, which is discharged out of the cylinder 1 through the overflow weir 1-10 and the outlet pipe 1-2 in sequence.

[0107] In the initial stage of the fluidized bed reaction device, the opening of the valve at the water inlet pipe 1-1 is gradually increased to gradually increase the inlet flow rate, so that the hydraulic retention time is gradually shortened until the fluidized bed reaction device is in stable operation;

[0108] In actual use, the initial stage is preferably 3-10 days, and the hydraulic retention time is preferably reduced from 6 hours to 0.5 hours;

[0109] During the stable operation of the fluidized bed reaction device, if the liquid level in the central tube 9 rises to the preset warning liquid level,

[0110] At this time, the solid retention of the filter media in the filter layer 4-2 increases, the biofilm thickens, and the void ratio between the filter media decreases, resulting in a decrease in the permeability of the filter layer 4-2, causing the water level in the central tube 9 to rise;

[0111] The valves at the water inlet pipe 1-1, the dosing pipe 1-6, and the water outlet pipe 1-2 are closed, the water pump 1-8 is stopped, the valve at the backwash water inlet pipe 1-4 is opened, the valve at the backwash discharge pipe 1-5 is opened, the backwash water pump is started, and at the same time, the speed of the agitator shaft is reduced;

[0112] At this time, the backwash water flows into the water distributor 7 from the backwash water inlet 7-1 through the backwash water inlet pipe 1-4 under the action of the backwash water pump, and then is distributed to the water distribution branch pipes 7-3 through the circular pipe 7-4, and flows upward from the holes 7-5 of the water distribution branch pipes 7-3 to backwash the filter layer 4-2, and then flows upward, overflows and is discharged to the backwash discharge pipe 1-5 through the overflow water weir 1-10;

[0113] At the same time, the shaft holder 6-5 of the raking mechanism 6 holds the stirring shaft 8-2 tightly, and drives the rake teeth 6-1 to rotate with the axis of the stirring shaft 8-1 as the rotating shaft through the rotating beam 6-3 and the rake rod 6-2, so as to rake the filter material particles, discharge the bubbles accumulated between the filter material particles, make the filter material particles accumulate again, and recreate the gaps between the filter material particles to restore the permeability of the filter layer 4-2;

[0114] After the rake teeth 6-1 rotate 1-3 times with the axis of the stirring shaft 8-1 as the rotating shaft, the liquid level in the central tube 9 is reduced to within 2 cm of the liquid level outside the central tube 9, and the filtering function of the filter layer 4-2 is completely restored;

[0115] Then shut down the backwash water pump, close the valves at the backwash water inlet pipe 1-4 and the backwash discharge pipe 1-5, release the shaft clamp 6-5, open the valves at the water inlet pipe 1-1, the dosing pipe 1-6 and the water outlet pipe 1-2, start the water pump 1-8, and continue the normal treatment of the wastewater.

[0116] In actual setting, the warning liquid level height can be set at 1-2 cm from the top of the center tube 9. The liquid level height can be monitored by a liquid level indicator with automatic alarm function, such as the QDY30A-BG immersion liquid level sensor of Shanghai Wujiu Automation Equipment Co., Ltd., or the LUSS-99305PD0DS ultrasonic liquid level meter of Shandong Dongrun.

[0117] The opening and closing of each valve, the starting and stopping of the water pumps 1-8, and the clamping and releasing of the shaft clamps 6-5 can be controlled by the control module, which can preferably be Siemens 200smartPLC, Mitsubishi FX2N PLC or Delta AS200 PLC.

[0118] Example 1

[0119] The method of using the above-mentioned fluidized bed reaction device for sulfur autotrophic denitrification and dephosphorization to carry out deep denitrification and dephosphorization treatment of sewage includes the following steps:

[0120] The first step is to prepare the paste-like autotrophic denitrification and dephosphorization agent into an autotrophic denitrification and dephosphorization suspension with a mass concentration of 5%, store it in a dosing tank, and stir it continuously to keep the autotrophic denitrification and dephosphorization suspension stable to prevent the precipitation of particles;

[0121] The above-mentioned autotrophic denitrification and dephosphorization agent has an elemental sulfur content of 86% on a dry basis, a nanostructured mineral material of 7%, and other components of 7%;

[0122] In the second step, 3% of the volume of the residual sludge obtained from the domestic sewage treatment plant is added into the cylinder 1 as a source of microbial strains;

[0123] The third step is to control the valve of the water inlet pipe 1-1 to be opened, and the sulfur autotrophic denitrification and dephosphorization agent suspension obtained in the first step is metered, continuously or intermittently added to the water inlet pipe 1-1 of the reaction device through the dosing pipe 1-6 according to the reaction equivalent ratio of nitrate nitrogen to autotrophic electron donor in water of 1:1.1, and then mixed with the wastewater and enter the denitrification and dephosphorization reactor, and the metering flow is controlled according to the hydraulic retention time of 6h;

[0124] Subsequently, the stirring driving machine 8-1 and the water pump 1-8 are started; the stirring driving machine 8-1 drives the stirring blade 8-3 to rotate via the stirring shaft 8-2, so that the stirring blade 8-3 slowly stirs at a speed of 2-3r / min, and at the same time, the water pump 1-8 drives the circulation of the mixed liquid, so that the autotrophic denitrification and dephosphorization agent and the microorganisms including the autotrophic denitrification bacteria are kept in a suspended state in the fluidized zone 2, and the sulfur autotrophic denitrification microorganisms are enriched and proliferated in a directional manner;

[0125] The denitrifying microorganisms in the inoculated microorganisms use electron donors to convert the nitrate nitrogen in the mixed liquid into nitrogen gas and discharge it to the outside of the cylinder 1 through the central tube 9. At the same time, the biomineralization converts the dissolved phosphate into solid iron phosphorus and calcium phosphorus precipitation;

[0126] In the fourth step, the rising suspension in the fluidized zone is separated into sinking particles and clarified liquid by settling in the settling zone 3. The clarified liquid passes through the filter layer 4-2 to produce clear water. During the process of the clarified liquid passing through the filter layer 4-2, a microbial film is formed on the surface of the filter particles. The fine particles including free microorganisms in the clarified liquid are retained by the filter layer 4-2. The clear water passing through the filter layer is the treated wastewater, which is discharged to the outside of the cylinder 1 through the overflow weir 1-10 and the outlet pipe 1-2 in sequence;

[0127] The filter material in the above filter layer has a compressive strength of >100kg / cm 2 The hard zeolite rock is crushed and sieved to obtain irregular particles of 2-6 mm;

[0128] In the initial 10 days of the fluidized bed reactor, the valve opening at the water inlet pipe 1-1 was gradually increased to gradually increase the inlet flow rate, so that the hydraulic retention time was gradually shortened from 6h to 0.5h, and the fluidized bed reactor operated stably;

[0129] During the stable operation of the fluidized bed reaction device, if the liquid level in the central tube 9 rises to 2 cm from its top, the liquid level indicator alarms, the control module controls the valves at the water inlet pipe 1-1, the dosing pipe 1-6, and the water outlet pipe 1-2 to close, the water pump 1-8 to stop, the valve at the backwash water inlet pipe 1-4 to open, the valve at the backwash discharge pipe 1-5 to open, the backwash water pump to start, and at the same time, reduce the speed of the stirring shaft;

[0130] At this time, the backwash water flows into the water distributor 7 from the backwash water inlet 7-1 through the backwash water inlet pipe 1-4 under the action of the backwash water pump, and then is distributed to the water distribution branch pipes 7-3 through the circular pipe 7-4, and flows upward from the holes 7-5 of the water distribution branch pipes 7-3 to backwash the filter layer 4-2, and then flows upward, overflows and is discharged to the backwash discharge pipe 1-5 through the overflow water weir 1-10;

[0131] At the same time, the shaft holder 6-5 of the raking mechanism 6 holds the stirring shaft 8-2 tightly, and drives the rake teeth 6-1 to rotate with the axis of the stirring shaft 8-1 as the rotating shaft through the rotating beam 6-3 and the rake rod 6-2, so as to rake the filter material particles, discharge the bubbles accumulated between the filter material particles, make the filter material particles accumulate again, and recreate the gaps between the filter material particles to restore the permeability of the filter layer 4-2;

[0132] After the rake teeth 6-1 rotate 1-3 times with the axis of the stirring shaft 8-1 as the rotating shaft, the liquid level in the central tube 9 is reduced to within 2 cm of the liquid level outside the central tube 9, and the filtering function of the filter layer 4-2 is completely restored;

[0133] Then shut down the backwash water pump, close the valves at the backwash water inlet pipe 1-4 and the backwash discharge pipe 1-5, release the shaft clamp 6-5, open the valves at the water inlet pipe 1-1, the dosing pipe 1-6 and the water outlet pipe 1-2, start the water pump 1-8, and continue the normal treatment of the wastewater.

[0134] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0135] 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 the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. 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 fluidized bed reaction device for sulfur autotrophic denitrification and dephosphorization, comprising a cylinder (1) having a cavity inside, wherein a water inlet pipe (1-1) and a water outlet pipe (1-2) are respectively connected from the bottom of the cylinder (1) to the bottom of the side wall and the top of the side wall, and characterized in that: The container comprises a clear water zone (5), a sedimentation zone (3) and a fluidization zone (2), which are separated from each other by a filter layer structure (4) and a water distributor (7) arranged in sequence from top to bottom to cover the cross section, and a raking mechanism (6); A circulation pipeline (1-7) is also provided, the two ends of which are respectively connected to the water distributor (7) and the bottom of the cylinder (1), and a water pump (1-8) is provided on the circulation pipeline (1-7); The filter layer structure (4) is filled with low-density porous medium filter material (4-3), and the raking mechanism (6) is used to rake the filter material.

2. The fluidized bed reaction device for sulfur autotrophic nitrogen and phosphorus removal according to claim 1, characterized in that: Also includes a central tube (9); The center of the filter layer structure (4) is provided with a central pipe (9) which is connected to the sedimentation area (3) and extends upward to above the clean water area (5); the central pipe (9) and the filter layer structure (4) are fixedly connected as a whole.

3. A fluidized bed reaction device for sulfur autotrophic nitrogen and phosphorus removal according to claim 2, characterized in that: The water distributor (7) comprises a circulating water inlet (7-2), a circular pipe (7-4) and a water distribution branch pipe (7-3); The circular tube (7-4) is an annular tubular structure, and each water distribution branch pipe (7-3) is arranged in the annular structure of the circular tube (7-4), and both ends are respectively connected to the circular tube (7-4); the circular tube (7-4) is provided with the circulating water inlet (7-2) connected to the circulating pipeline (1-7), and the top and both sides of the water distribution branch pipe (7-3) are densely covered with holes (7-5).

4. The fluidized bed reaction device for sulfur autotrophic denitrification and dephosphorization according to claim 3, characterized in that: It also includes a mud discharge pipe (1-3), a backwash discharge pipe (1-5) and a backwash water inlet pipe (1-4); the water distributor (7) is also provided with a backwash water inlet (7-1) located on the opposite side of the circulating water inlet (7-2); the backwash water inlet (7-1) is connected to the backwash water inlet pipe (1-4); A mud discharge pipe (1-3) is provided at the bottom of the side wall of the cylinder (1) on the opposite side to the water inlet pipe (1-1), and the backwash discharge pipe (1-5) is connected in parallel with the water outlet pipe (1-2) to the top of the side wall of the cylinder (1).

5. The fluidized bed reaction device for sulfur autotrophic nitrogen and phosphorus removal according to claim 4, characterized in that: It also includes a stirring mechanism (8), wherein the stirring mechanism (8) includes a stirring driving machine (8-1), a stirring shaft (8-2), a stirring blade (8-3) and a limiting end (8-4); The stirring shaft (8-2) passes through the central tube (9) from top to bottom and extends to the bottom of the fluidization zone (2), the top end of which is axially fixed to the output end of the fixedly installed stirring driving machine (8-1), and the bottom end is fixedly installed to the stirring blade (8-3); a gap is left between the stirring shaft (8-2) and the central tube (9); The bottom of the stirring blade (8-3) is provided with a downwardly convex limiting end (8-4) at the extension line of the axis of the stirring shaft (8-2), and the bottom of the cylinder (1) is correspondingly provided with a limiting cylinder (1-9) matching with the limiting end (8-4); The limiting end (8-4) is inserted into the limiting cylinder (1-9) and is used to limit the lower end of the stirring shaft (8-2).

6. A fluidized bed reaction device for sulfur autotrophic nitrogen and phosphorus removal according to claim 5, characterized in that: The raking mechanism (6) comprises raking teeth (6-1), a raking rod (6-2), a rotating beam (6-3), an end roller (6-4) and a shaft clamp (6-5); The top end of the rake rod (6-2) is fixedly connected to the rotating beam (6-3), and the bottom end is fixedly provided with rake teeth (6-1) in a row, each extending into the filter material (4-3); The stirring shaft (8-2) is arranged to penetrate the rotating beam (6-3), and a rotating pair is formed between the two to support the two to rotate relative to each other around the axis of the stirring shaft (8-2); An end roller (6-4) is rotatably mounted at each end of the rotating beam (6-3); the end roller (6-4) is mounted on the top of the upper end surface of the cylinder (1), and the outer side thereof is a radially outwardly convex limit edge structure; the limit edge structure is clamped on the outer side of the cylinder (1), and together with the stirring shaft (8-2) limits the relative position of the rotating beam (6-3) and the end roller (6-4) and the cylinder (1); The outer ring and inner ring of the shaft clamp (6-5) are respectively fixedly mounted on the rotating beam (6-3) and the stirring shaft (8-2), and when the shaft clamp (6-5) is clamped, the outer ring and the inner ring are locked to limit the relative rotation of the stirring shaft (8-2) and the rotating beam (6-3).

7. A fluidized bed reaction device for sulfur autotrophic denitrification and dephosphorization according to claim 4 or 5, characterized in that: Also included are baffles (1-11); A baffle (1-11) is provided above the top opening of the central tube (9), shielding the central tube (9) and leaving a gap between the baffle and the top end of the central tube (9).

8. The fluidized bed reaction device for sulfur autotrophic nitrogen and phosphorus removal according to claim 1, characterized in that: The filter layer structure (4) comprises a support structure (4-1), a filter layer (4-2) and the filter material (4-3); The filter layer (4-2) is a bin structure with a mesh bottom plate, and the filter material (4-3) is filled in the filter layer (4-2); The bottom of the filter layer (4-2) is fixedly mounted with a triangular rib-shaped support structure (4-1), and the support structure (4-1) is fixedly mounted on the cylinder (1) and is used to support the filter layer (4-2).

9. The fluidized bed reaction device for sulfur autotrophic nitrogen and phosphorus removal according to claim 1, characterized in that: An overflow water outlet weir (1-10) fixedly mounted on the cylinder (1) is provided in the cylinder (1) above the filter layer structure (4); the water outlet pipe (1-2) is connected to the clean water area (5) through the overflow water outlet weir (1-10); It also comprises a dosing pipe (1-6); one end of the circulation pipeline (1-7), the dosing pipe (1-6) and the water inlet pipe (1-1) are connected in parallel and fixed to the bottom of the side wall of the cylinder (1), and are connected to the fluidization zone (2).

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