A sewage treatment method and device using enhanced sulfur autotrophic removal of nitrates in water

Abstract

A sewage treatment method and device for removing nitrates from water by strengthening sulfur autotrophy, the sewage treatment method is to set a sulfur autotrophic denitrification functional area and a sulfur autotrophic byproduct denitrification functional area, the sulfur autotrophic denitrifying bacteria in the sulfur autotrophic denitrification functional area use sulfur as an electron donor, circulate the sewage in the sulfur autotrophic denitrification functional area, and the circulated sewage is passed from the sulfur autotrophic denitrification functional area to the sulfur autotrophic byproduct denitrification functional area. The sewage treatment device includes an upper cylinder and a lower cylinder; a sulfur autotrophic byproduct denitrification functional area is formed in the upper cylinder, and a sulfur autotrophic denitrification functional area is formed in the lower cylinder, and the sulfur autotrophic denitrification functional area and the sulfur autotrophic byproduct denitrification functional area are both filled with anaerobic sludge and fillers, and the sulfur autotrophic denitrification functional area is also filled with sulfur particles as electron donors. The present invention can improve the electron utilization rate in sulfur autotrophic denitrification, reduce the content of sulfide and sulfate in effluent, and balance the pH value of effluent.

Description

Technical Field

[0001] The invention relates to the field of sewage treatment technology and equipment, and in particular to a sewage treatment method and device for removing nitrates in water by strengthening sulfur autotrophy. Background Art

[0002] Due to the use of large amounts of nitrogen fertilizers, the irrational disposal of animal manure, domestic sewage, and nitrogen-containing industrial wastewater, nitrates are common anionic pollutants in surface or groundwater. Nitrates are less toxic, but after entering the human body, they are reduced to more toxic nitrites. my country's latest "Sanitary Standards for Drinking Water" (GB5749-2006) clearly stipulates that the nitrate nitrogen concentration shall not exceed 10 mg / L, so it is necessary to remove nitrates from water.

[0003] In the existing technology, nitrates in water are removed by sulfur autotrophic denitrification technology. Nitrates can be converted into N2 by sulfur autotrophic denitrification technology, and the reaction speed is fast and the degree of automation is high. Sulfur autotrophic denitrification technology converts nitrates into N2 and generates SO4 at the same time. 2- and H + Moreover, sulfur undergoes disproportionation reaction to generate sulfide and H + , the H produced by the reaction + The water environment becomes acidic, and the SO4 generated by the reaction 2- , sulfide is discharged with the effluent. This leads to problems such as excessive sulfide and sulfate content in the effluent of the prior art sulfur autotrophic denitrification technology and decreased effluent pH value. In addition, the electron utilization rate in the process of removing nitrates by sulfur autotrophic denitrification in the prior art is low, and the cost is high. Summary of the invention

[0004] The present invention aims to provide a sewage treatment method and device for removing nitrate in water by enhancing sulfur autotrophy, which can improve the electron utilization rate in sulfur autotrophic denitrification, reduce the content of sulfide and sulfate in effluent, and balance the pH value of effluent.

[0005] In order to solve the above technical problems, the specific scheme adopted by the present invention is a sewage treatment method for removing nitrates in water by strengthening sulfur autotrophy: setting a sulfur autotrophic denitrification functional area and a sulfur autotrophic byproduct denitrification functional area, and the sulfur autotrophic denitrifying bacteria in the sulfur autotrophic denitrification functional area use sulfur as an electron donor to convert nitrates in sewage into N2 and generate SO4 2- At the same time, the sulfur in the sulfur autotrophic denitrification functional area undergoes disproportionation reaction to generate SO4 2- and sulfide; circulate the wastewater in the sulfur autotrophic denitrification functional area to make part of the SO4 2-The recycled sewage is passed from the sulfur autotrophic denitrification functional area to the sulfur autotrophic byproduct denitrification functional area. The sulfur autotrophic denitrification bacteria in the sulfur autotrophic byproduct denitrification functional area use the sulfur and sulfide in the recycled sewage as electron donors to convert the nitrate in the sewage in the sulfur autotrophic byproduct denitrification functional area into N2 and SO4 2- After discharge.

[0006] A sewage treatment device for removing nitrates in water by strengthening sulfur autotrophy comprises an upper cylinder and a lower cylinder; a sulfur autotrophic byproduct denitrification functional zone is formed in the upper cylinder, and a sulfur autotrophic denitrification functional zone is formed in the lower cylinder; both the sulfur autotrophic denitrification functional zone and the sulfur autotrophic byproduct denitrification functional zone are filled with anaerobic sludge and fillers; and the sulfur autotrophic denitrification functional zone is also filled with sulfur particles as electron donors;

[0007] An upper water inlet is provided at the bottom of the upper cylinder, which is connected to the second water pipeline, on which a second peristaltic pump is arranged, and the second peristaltic pump is used to pump sewage into the sulfur autotrophic byproduct denitrification functional area; a lower water inlet is provided at the bottom of the lower cylinder, which is connected to the first water pipeline, on which a first peristaltic pump is arranged, and the first peristaltic pump is used to pump sewage into the sulfur autotrophic denitrification functional area; a water outlet is provided at the top of the lower cylinder, which is connected to a circulation pipeline, and the water outlet end of the circulation pipeline is connected to the first water pipeline; a two-position three-way solenoid valve is arranged at the intersection of the circulation pipeline and the first water pipeline.

[0008] As a further optimization of the sewage treatment device of the present invention for removing nitrates in water by enhanced sulfur autotrophy: the filler includes a supporting material and a pH buffering filler; the supporting materials in the sulfur autotrophic denitrification functional area and the sulfur autotrophic by-product denitrification functional area are both volcanic rocks, and the pH buffering fillers are all oyster shells.

[0009] As a further optimization of the sewage treatment device for removing nitrates in water by enhanced sulfur autotrophy of the present invention: the volume ratio of sulfur particles in the sulfur autotrophic denitrification functional area is 40%, the volume ratio of supporting materials is 40%, and the volume ratio of pH buffer fillers is 20%; the volume ratio of supporting materials in the sulfur autotrophic by-product denitrification functional area is 50%, and the volume ratio of pH buffer fillers is 50%.

[0010] As a further optimization of the sewage treatment device for removing nitrates from water by enhanced sulfur autotrophy of the present invention: the second peristaltic pump and the two-position three-way solenoid valve are connected to the timing switch through a circuit.

[0011] As a further optimization of the sewage treatment device for removing nitrates in water by enhanced sulfur autotrophication according to the present invention: flanges are provided on the top and bottom of the upper cylinder and the lower cylinder, the flange at the bottom of the upper cylinder is aligned with the flange at the top of the lower cylinder, and bolts are installed to fix the upper cylinder and the lower cylinder in connection; a base is provided at the bottom of the lower cylinder, and the flange at the bottom of the lower cylinder is fixed to the base by bolts.

[0012] As a further optimization of the sewage treatment device of the present invention for removing nitrates in water by enhanced sulfur autotrophication: a cover plate is arranged on the top of the upper cylinder, and an exhaust port is opened on the cover plate; the cover plate is aligned with the flange at the top of the upper cylinder, and bolts are passed between the cover plate and the flange at the top of the upper cylinder.

[0013] As a further optimization of the sewage treatment device of the present invention for removing nitrates in water by enhanced sulfur autotrophy: support plates are provided at the bottom of the sulfur autotrophic denitrification functional zone in the upper cylinder and at the bottom of the sulfur autotrophic byproduct denitrification functional zone in the lower cylinder, and circular holes with a diameter of 2 mm are opened on the support plates.

[0014] As a further optimization of the sewage treatment device for removing nitrates from water by enhancing sulfur autotrophy of the present invention: baffles are arranged in the upper cylinder and the lower cylinder between the sulfur autotrophic denitrification functional area and the sulfur autotrophic byproduct denitrification functional area.

[0015] As a further optimization of the sewage treatment device for removing nitrates from water by enhanced sulfur autotrophication according to the present invention: the water inlet ends of the first water pipeline and the second water pipeline are connected to the sewage pool.

[0016] Beneficial Effects

[0017] The present invention discloses a sewage treatment device for removing nitrate from water by strengthening sulfur autotrophy. The sulfur particles in the sulfur autotrophic denitrification functional area in the lower cylinder provide electrons as electron donors, and the sulfur autotrophic denitrification microorganisms convert the nitrate in the sewage into N2 and generate SO4 at the same time. 2- . SO4 in the sulfur autotrophic denitrification functional zone 2- During the internal circulation, it is converted into sulfide. After the recycled sewage is passed into the sulfur autotrophic byproduct denitrification functional area, the sulfide in the recycled sewage and the sulfur element carried upward provide electrons, so that the sulfur autotrophic denitrification microorganisms convert the nitrate in the sewage in the sulfur autotrophic byproduct denitrification functional area into N2 and SO4. 2- During the entire nitrate removal process, the raw material sulfur in the form of elemental sulfur and sulfide provides electrons for the microbial reactions in the lower cylinder and the upper cylinder respectively, which greatly improves the utilization rate of electrons and reduces the input cost of raw materials.

[0018] In the sulfur autotrophic denitrification functional zone in the lower cylinder, the SO4 generated when removing nitrate 2-Instead of being discharged directly, it is converted into sulfide through internal circulation and provides electrons for the denitrification functional area of ​​sulfur autotrophic byproducts. Therefore, the present invention removes SO4 generated by a specific amount of nitrate. 2- Compared with the prior art, the amount of SO4 in the effluent of the present invention is significantly reduced. 2- Significantly reduced.

[0019] In the present invention, sulfur undergoes a disproportionation reaction in the sulfur autotrophic denitrification functional zone to generate sulfide and SO4 2- The sulfide generated by the disproportionation reaction rises with the recycled sewage and enters the sulfur autotrophic byproduct denitrification functional area, using the sulfide as an electron donor to convert nitrate into N2, thereby reducing the sulfide content in the effluent.

[0020] In the present invention, although H is produced in the process of removing nitrate by sulfur in the sulfur autotrophic denitrification functional zone, + However, sulfide reacts in the sulfur autotrophic byproduct denitrification functional zone and consumes H + , thereby balancing the pH value of the effluent. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a cross-sectional structural schematic diagram of the present invention;

[0022] Figure 2 for Figure 1 A schematic diagram of the enlarged structure of part A;

[0023] Figure 3 It is a statistical table of sulfate and nitrate content at inlet and outlet;

[0024] Figure numerals: 1. upper cylinder, 2. filler, 3. sulfur autotrophic by-product denitrification functional area, 4. upper water inlet, 5. second peristaltic pump, 6. second water pipeline, 7. water outlet, 8. lower cylinder, 9. sulfur autotrophic denitrification functional area, 10. circulation pipeline, 11. sewage tank, 12. two-position three-way solenoid valve, 13. first peristaltic pump, 14. first water pipeline, 15. lower water inlet, 16. base, 17. flange, 18. support plate, 19. partition, 20. bolt, 21. exhaust port, 22. cover plate. DETAILED DESCRIPTION

[0025] like Figure 1As shown, a sewage treatment device for removing nitrates from water by enhanced sulfur autotrophy comprises an upper cylinder 1 and a lower cylinder 8, wherein the upper cylinder 1 is located above the lower cylinder 8. Flanges 17 are provided on the outer peripheries of the top and bottom of the upper cylinder 1, and flanges 17 are provided on the outer peripheries of the top and bottom of the lower cylinder 8. The flange 17 at the bottom of the upper cylinder 1 is aligned with the flange 17 at the top of the lower cylinder 8, and four bolts 20 are evenly spaced and installed on the two aligned flanges 17, and the upper cylinder 1 is stably fixed to the lower cylinder 8 by the fixing of the bolts 20.

[0026] A cover plate 22 is provided at the top of the upper cylinder 1, and an exhaust port 21 is provided on the cover plate 22. The cover plate 22 is aligned with the flange 17 on the top of the upper cylinder 1, and bolts 20 are provided between the cover plate 22 and the corresponding flange 17 to fix the cover plate 22 on the flange 17. A base 16 is provided at the bottom of the lower cylinder 8, and the base 16 is aligned with the flange 17 at the bottom of the lower cylinder 8, and bolts 20 are provided between the base 16 and the corresponding flange 17 to fix the lower cylinder 8 on the base 16.

[0027] The upper cylinder 1 forms a sulfur autotrophic byproduct denitrification functional zone 3, and the lower cylinder 8 forms a sulfur autotrophic denitrification functional zone 9. The sulfur autotrophic denitrification functional zone 9 and the sulfur autotrophic byproduct denitrification functional zone 3 are filled with anaerobic sludge and filler 2, which are mixed and put in. It is also filled with an electron donor, which is sulfur particles, and its main component is sulfur. The anaerobic sludge is taken from the anaerobic pool of the Wulongkou Sewage Treatment Plant in Zhengzhou. The anaerobic sludge is mainly used to inoculate sulfur autotrophic denitrifying bacteria. The sulfur autotrophic denitrifying bacteria reaction needs to be connected with the activated sludge. There are various denitrifying bacteria in the activated sludge. After a period of training, the denitrifying bacteria that remove nitrates can survive, and other bacteria will die, completing the domestication of sulfur autotrophic denitrifying bacteria. The filler 2 includes a supporting material and a pH buffer filler. The supporting materials in the sulfur autotrophic denitrification functional zone 9 and the sulfur autotrophic byproduct denitrification functional zone 3 are all volcanic rocks, and the pH buffer fillers are all oyster shells. The role of oyster shells is to provide an alkaline source for sulfur autotrophic denitrification, so sulfur autotrophic denitrification does not need to add an additional alkaline source. At the same time, the setting of oyster shells provides an alkaline environment for the disproportionation reaction of sulfur.

[0028] The volume ratio of sulfur particles in the sulfur autotrophic denitrification functional area 9 is 40%, the volume ratio of supporting materials is 40%, and the volume ratio of pH buffer filler is 20%. The volume ratio of supporting materials in the sulfur autotrophic byproduct denitrification functional area 3 is 50%, and the volume ratio of pH buffer filler is 50%.

[0029] A support plate 18 is provided on the inner wall of the upper cylinder 1 located below the sulfur autotrophic byproduct denitrification functional zone 3, and a support plate 18 is provided on the inner wall of the lower cylinder 8 located at the bottom of the sulfur autotrophic denitrification functional zone 9. The support plates 18 are used to prevent the mixture of anaerobic sludge and filler 2 from falling, and a 2mm round hole is provided on the support plate 18. A partition 19 is provided on the inner wall of the lower cylinder 8 between the sulfur autotrophic denitrification functional zone 9 and the sulfur autotrophic byproduct denitrification functional zone 3. The provision of the partition 19 can further prevent the filler 2 in the sulfur autotrophic byproduct denitrification functional zone 3 from falling into the sulfur autotrophic denitrification functional zone 9. The partition 19 is also provided with holes so that the water flow in the sulfur autotrophic denitrification functional zone 9 can enter the sulfur autotrophic byproduct denitrification functional zone 3 under the thrust from bottom to top.

[0030] A lower water inlet 15 is provided at the bottom of the lower cylinder 8, and the lower water inlet 15 is connected to a first water pipeline 14. The water inlet end of the first water pipeline 14 is connected to the lower water inlet 15, and the water inlet end of the first water pipeline 14 is connected to the sewage pool 11. A first peristaltic pump 13 is provided on the first water pipeline 14, and the first peristaltic pump 13 is used to pump sewage into the sulfur autotrophic denitrification functional area 9.

[0031] A water outlet 7 is provided at the top of the lower cylinder 8, and the water outlet 7 is connected to a circulation pipeline 10. The water inlet end of the circulation pipeline 10 is connected to the water outlet 7, and the water outlet end of the circulation pipeline 10 is connected to the first water pipeline 14. A two-position three-way solenoid valve 12 is provided at the intersection of the circulation pipeline 10 and the first water pipeline 14, and the two-position three-way solenoid valve 12 is used to control the sewage to enter the first water pipeline 14 with the opening and closing of the circulation in the sulfur autotrophic denitrification functional area 9.

[0032] An upper water inlet 4 is provided at the bottom of the upper cylinder 1, and the upper water inlet 4 is connected to a second water pipeline 6. The water outlet of the second water pipeline 6 is connected to the upper water inlet 4, and the water inlet of the second water pipeline 6 is connected to the sewage pool 11. A second peristaltic pump 5 is provided on the second water pipeline 6, and the second peristaltic pump 5 is used to pump the sewage in the sewage pool 11 to the sulfur autotrophic byproduct denitrification functional area 3.

[0033] like Figure 1 and Figure 2 As shown, the second peristaltic pump 5 and the two-position three-way solenoid valve 12 are connected to a timing switch through a circuit, and the timing switch is used to control the intermittent water inflow, intermittent circulation and intermittent water outflow in the sulfur autotrophic denitrification functional area 9 and the sulfur autotrophic byproduct denitrification functional area 3. The timing switch controls the opening and closing of the two-position three-way solenoid valve 12, thereby controlling the sewage to enter the sulfur autotrophic denitrification functional area 9 from the first water pipeline 14. The first peristaltic pump 13 is started, and the timing switch controls the valve ports a and c on the two-position three-way solenoid valve 12 to open and the valve port b to close, and the sewage in the sewage pool 11 enters the sulfur autotrophic denitrification functional area 9 from the lower water inlet 15 through the first water pipeline 14.

[0034] The sulfur particles in the sulfur autotrophic denitrification functional zone 9, that is, sulfur element, undergo an oxidation-reduction reaction with the nitrate in the sewage, and the reaction equation is: Thus, nitrate is converted into N2 and SO4 2- , removing nitrates from wastewater. At the same time, under the alkaline conditions provided by oyster shells, sulfur in the sulfur autotrophic denitrification functional zone 9 undergoes a disproportionate reaction to generate SO4 2- The equation for the disproportionation reaction of sulfur with sulfide and elemental sulfur is:

[0035] Furthermore, the timing switch controls the opening and closing of the two-position three-way solenoid valve 12 to control the internal circulation time of the sewage in the sulfur autotrophic denitrification functional area 9. The sewage in the sulfur autotrophic denitrification functional area 9 flows out from the outlet 7 to the circulation pipeline 10, and the valve port a on the two-position three-way solenoid valve 12 is closed, so that the sewage in the sewage pool 11 cannot enter the sulfur autotrophic denitrification functional area 9 through the first water pipeline 14. The valve ports b and c on the two-position three-way solenoid valve 12 are opened, and the sewage enters the first water pipeline 14 and enters the sulfur autotrophic denitrification functional area 9 from the lower water inlet 15, completing an internal circulation. When the sewage circulates internally, part of the SO4 2- Converted into sulfide, the redox reaction equation is: Among them, C3H8O3 represents organic matter, which is the dead bacteria in anaerobic sludge.

[0036] After the sewage in the sulfur autotrophic denitrification functional area 9 completes the circulation, the timer switch controls the valve ports a and c on the two-position three-way solenoid valve 12, and closes the valve port b on the two-position three-way solenoid valve 12, and the sewage in the sewage pool 11 enters the sulfur autotrophic denitrification functional area 9 and pushes the sewage that has completed the circulation to rise and enter the sulfur autotrophic byproduct denitrification functional area 3. At the same time, the timer switch controls the second peristaltic pump 5 to start, and the sewage in the sewage pool 11 enters the sulfur autotrophic byproduct denitrification functional area 3 through the second water pipe 6 from the upper water inlet 4. The sulfur autotrophic byproduct denitrification functional area 3 and the sulfur autotrophic denitrification functional area 9 are treated with water synchronously to improve the treatment efficiency of removing nitrates in sewage.

[0037] In the sulfur autotrophic byproduct denitrification zone 3, the sulfide and sulfur element in the sewage that has completed the cycle (sulfur element is the sulfur particles brought into the sulfur autotrophic byproduct denitrification functional zone 3 from the sulfur autotrophic byproduct denitrification functional zone 9 along with the sewage) are used as electron donors to convert the nitrate entering the sulfur autotrophic byproduct denitrification functional zone 3 into N2 and SO4. 2- After discharge, the redox equation of the reaction between sulfur element as electron donor and nitrate is: The equation for the redox reaction between sulfide and nitrate as electron donor is: In the above equation, H is consumed during sulfide denitrification. + , and then balance the pH value of the effluent. The N2 produced by the reaction is discharged from the exhaust port 21, and the wastewater after the reaction is discharged through the drain port set on the upper cylinder 1.

[0038] In the sulfur autotrophic denitrification functional zone 9 in the lower cylinder 8, SO4 generated when removing nitrate 2- Instead of being discharged directly, it is converted into sulfide through internal circulation and provides electrons for the sulfur autotrophic byproduct denitrification functional zone 3. Therefore, the present invention removes SO4 generated by a specific amount of nitrate. 2- Compared with the prior art, the amount of SO4 in the effluent of the present invention is significantly reduced. 2- According to theoretical calculations, when sulfur is used alone to provide electrons for the removal of nitrate by sulfur-supplying autotrophic denitrifying microorganisms, 7.27 mg of sulfate is generated for every 1 mg of nitrate removed. Figure 3 As shown, after 11 tests, the amount of sulfate generated for every 1 mg of nitrate removed in the present invention was less than 7.27 mg, which proves that under the condition of the same treatment amount, the discharge amount of sulfate in the present invention is significantly reduced.

[0039] The specific implementation of the present invention is as follows: First, the first peristaltic pump 13 is started, the timing switch controls the two-position three-way solenoid valve 12 to start, the a and c valve ports on the two-position three-way solenoid valve 12 are opened, and the sewage enters the sulfur autotrophic denitrification functional area 9 from the lower water inlet 15 through the first water pipeline 14. Secondly, after the b and c valve ports on the two-position three-way solenoid valve 12 are opened by the timing switch, the sewage in the sulfur autotrophic denitrification functional area 9 flows out from the water outlet 7 into the circulation pipeline 10, and re-enters the sulfur autotrophic denitrification functional area 9 from the lower water inlet 15 through the first water pipeline 14 for internal circulation. Finally, after the circulation of the sewage in the sulfur autotrophic denitrification functional area 9 is completed, the timing switch controls the a and c valve ports on the two-position three-way solenoid valve 12 to open, and the sewage in the sewage pool 11 enters the sulfur autotrophic denitrification functional area 9 and pushes the sewage that has completed the circulation to rise and enter the sulfur autotrophic byproduct denitrification functional area 3. At the same time, the timing switch controls the second peristaltic pump 5 to start, and the sewage in the sewage pool 11 enters the sulfur autotrophic byproduct denitrification functional area 3 from the upper water inlet 4 through the second water delivery pipeline 6. This cycle is repeated to complete the removal of nitrates in the sewage.

Claims

1. A method for treating sewage by removing nitrate from water by strengthening sulfur autotrophy, characterized in that: A sulfur autotrophic denitrification functional zone (9) and a sulfur autotrophic byproduct denitrification functional zone (3) are set up. The sulfur autotrophic denitrifying bacteria in the sulfur autotrophic denitrification functional zone (9) use sulfur as an electron donor to convert nitrate in the sewage into N2 and generate SO4 2- At the same time, the sulfur in the sulfur autotrophic denitrification functional zone (9) undergoes a disproportionate reaction to generate SO4 2- and sulfide; circulate the wastewater in the sulfur autotrophic denitrification functional area (9) to make part of the SO4 2- The recycled sewage is passed from the sulfur autotrophic denitrification functional zone (9) to the sulfur autotrophic byproduct denitrification functional zone (3). The sulfur autotrophic denitrifying bacteria in the sulfur autotrophic byproduct denitrification functional zone (3) use the sulfur and sulfide in the recycled sewage as electron donors to convert the nitrate in the sewage in the sulfur autotrophic byproduct denitrification functional zone (3) into N2 and SO4. 2- After discharge; When the sewage is circulated, part of the SO4 2- Converted into sulfide, the redox reaction equation is: , where C3H8O3 represents organic matter, which is the dead bacteria in anaerobic sludge.

2. A sewage treatment device for implementing the sewage treatment method for removing nitrates from water by enhanced sulfur autotrophy according to claim 1, characterized in that: The invention comprises an upper cylinder (1) and a lower cylinder (8); a sulfur autotrophic byproduct denitrification functional zone (3) is formed in the upper cylinder (1), and a sulfur autotrophic denitrification functional zone (9) is formed in the lower cylinder (8); the sulfur autotrophic denitrification functional zone (9) and the sulfur autotrophic byproduct denitrification functional zone (3) are both filled with anaerobic sludge and filler (2); and the sulfur autotrophic denitrification functional zone (9) is also filled with sulfur particles as electron donors; An upper water inlet (4) is provided at the bottom of the upper cylinder (1), the upper water inlet (4) is connected to a second water delivery pipeline (6), a second peristaltic pump (5) is provided on the second water delivery pipeline (6), and the second peristaltic pump (5) is used to pump sewage into the sulfur autotrophic byproduct denitrification functional area (3); a lower water inlet (15) is provided at the bottom of the lower cylinder (8), the lower water inlet (15) is connected to a first water delivery pipeline (14), a first peristaltic pump (13) is provided on the first water delivery pipeline (14), and the first peristaltic pump (13) is used to pump sewage into the sulfur autotrophic denitrification functional area (9); a water outlet (7) is provided at the top of the lower cylinder (8), the water outlet (7) is connected to a circulation pipeline (10), and the water outlet end of the circulation pipeline (10) is connected to the first water delivery pipeline (14); a two-position three-way solenoid valve (12) is provided at the intersection of the circulation pipeline (10) and the first water delivery pipeline (14).

3. A sewage treatment device according to claim 2, characterized in that: The filler (2) includes a supporting material and a pH buffering filler; the supporting materials in the sulfur autotrophic denitrification functional area (9) and the sulfur autotrophic byproduct denitrification functional area (3) are all volcanic rocks, and the pH buffering fillers are all oyster shells.

4. A sewage treatment device according to claim 3, characterized in that: The volume ratio of sulfur particles in the sulfur autotrophic denitrification functional zone (9) is 40%, the volume ratio of the supporting material is 40%, and the volume ratio of the pH buffer filler is 20%; the volume ratio of the supporting material in the sulfur autotrophic byproduct denitrification functional zone (3) is 50%, and the volume ratio of the pH buffer filler is 50%.

5. A sewage treatment device according to claim 2, characterized in that: The second peristaltic pump (5) and the two-position three-way solenoid valve (12) are connected to the timing switch via an electric circuit.

6. A sewage treatment device according to claim 2, characterized in that: The top and bottom of the upper cylinder (1) and the lower cylinder (8) are both provided with flanges (17); the flange (17) at the bottom of the upper cylinder (1) is aligned with the flange (17) at the top of the lower cylinder (8), and bolts (20) are installed to fix the upper cylinder (1) and the lower cylinder (8) together; a base (16) is provided at the bottom of the lower cylinder (8); the flange (17) at the bottom of the lower cylinder (8) and the base (16) are fixed by bolts (20).

7. A sewage treatment device according to claim 6, characterized in that: A cover plate (22) is provided at the top of the upper cylinder (1), and an exhaust port (21) is provided on the cover plate (22); the cover plate (22) is aligned with a flange (17) at the top of the upper cylinder (1), and bolts (20) are inserted between the cover plate (22) and the flange (17) at the top of the upper cylinder (1).

8. A sewage treatment device according to claim 2, characterized in that: A support plate (18) is provided at the bottom of the sulfur autotrophic denitrification functional area (9) in the upper cylinder (1) and at the bottom of the sulfur autotrophic byproduct denitrification functional area (3) in the lower cylinder (8). The support plate (18) is provided with a circular hole with a hole diameter of 2 mm.

9. A sewage treatment device according to claim 2, characterized in that: A partition (19) is provided between the sulfur autotrophic denitrification functional area (9) and the sulfur autotrophic byproduct denitrification functional area (3) in the upper cylinder (1) and the lower cylinder (8).

10. A sewage treatment device according to claim 2, characterized in that: The water inlet ends of the first water delivery pipeline (14) and the second water delivery pipeline (6) are connected to the sewage tank (11).

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