A method for directional regulation of sulfur-based filler autotrophic denitrification filter

Abstract

The application provides a method for directional regulation of sulfur-based filler autotrophic denitrification filter, which realizes denitrification treatment of wastewater by adjusting water drop height, exposing reaction bed and adding sulfur source, in addition, a dissolved oxygen probe, a liquid level detector, a bed height monitor and a nitrate nitrogen online monitoring device are arranged in the denitrification filter, real-time monitoring of nitrate nitrogen content of wastewater in and out of the filter is realized, a difference between the two is calculated through a central control system, the difference is compared with a set value, and the water drop height, the exposed reaction bed or the added sulfur source is timely regulated, the method can not only realize high-load regulation of denitrification, but also realize low-load regulation, so that the removal content of nitrate nitrogen is controlled within a certain range, which is not only beneficial to improving the treatment effect of wastewater, but also can effectively reduce the treatment cost, and is suitable for application in actual production.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of sewage treatment and resource utilization, in particular to a method for controlling drop height, exposing reaction bed and adding sulfur source to direct regulation of sulfur-based packing autotrophic denitrification filter. BACKGROUND

[0002] At present, the amount of sewage discharge is gradually increasing, and the total nitrogen concentration in sewage is becoming higher and higher. Sewage discharge and treatment problems are increasingly prominent, attracting widespread attention, and sewage treatment is becoming more and more urgent.

[0003] Among the many processes of sewage treatment, biological sewage treatment technology is favored by more and more researchers due to its low cost and high treatment efficiency. However, due to the increasing total nitrogen concentration in the discharged sewage and the gradual imbalance of carbon-nitrogen ratio, the denitrification step of biological treatment is not very thorough, so water quality fluctuations often occur, which often leads to fluctuations in treatment effect. The current common solution is to replace the traditional carbon source heterotrophic filter with a sulfur-based packing autotrophic denitrification filter, but the sulfur-based packing autotrophic denitrification filter still faces the problem of fluctuation in treatment effect, and there is currently no method for load regulation for sulfur-based packing autotrophic denitrification filter.

[0004] The existing traditional carbon source heterotrophic denitrification filter removes nitrate nitrogen content in tail water by adding COD external carbon source as electron donor, and its denitrification load regulation is mainly achieved by changing the dosage of COD external carbon source.

[0005] The sulfur-based packing autotrophic denitrification filter needs to pre-throw sulfur-based carriers into the filter, so it cannot achieve load regulation by changing the dosage of COD external carbon source.

[0006] In addition, existing research has shown that dissolved oxygen as an electron acceptor is preferred over nitrate and electron donor reaction.

[0007] For example: Chinese patent CN 211311023 U discloses a denitrification filter for reducing carbon source consumption. By removing dissolved oxygen in wastewater to the maximum extent, the carbon source consumption in the wastewater denitrification process is reduced, but the device still needs to add carbon source, which not only increases the cost, but also has poor denitrification level and poor sewage treatment effect when the carbon source is insufficient.

[0008] For example: Application No. 202011629562.4. The invention relates to a sewage treatment device with intelligent monitoring and backwashing enhanced denitrification process, which comprises a first filter tank and a second filter tank, one side of the bottom of the first filter tank is connected with a sewage sample inlet unit, the other side of the top of the first filter tank is connected with the connecting pipe, the other end of the connecting pipe is connected with one side of the bottom of the second filter tank, and the other side of the top of the second filter tank is connected with a sewage sample outlet unit; a slow-release carbon source filler layer is arranged in the middle of the first filter tank, and a denitrifying bacteria filler layer is arranged in the middle of the second filter tank; a backwashing unit is arranged at the top of the first filter tank and the second filter tank respectively, and a backwashing discharge unit is arranged at the bottom of the first filter tank and the second filter tank respectively. The device can enhance the denitrification process by increasing the carbon source in the water, enhance the degradation function of pollutants in the water body, and realize intelligent control through the sensor, which is more convenient and simple to operate, and greatly improves the denitrification and phosphorus removal efficiency of the traditional treatment process. However, this patent still involves the problem of carbon source addition.

[0009] Sulfur autotrophic denitrification technology has good application prospects for advanced treatment of municipal wastewater due to its low operating cost and small sludge production. However, the existing filter process design method lacks effective control means for denitrification load during operation, which is difficult to adapt to the objective situation of water quality fluctuation. SUMMARY

[0010] Based on the above technical background, the inventors made great efforts and found that by adjusting the drop height, exposed reaction bed and adding sulfur source, the denitrification treatment of wastewater can be realized. At the same time, by setting dissolved oxygen probes, liquid level detectors, bed height monitors and nitrate online monitoring equipment in the denitrification filter, real-time monitoring of the nitrate nitrogen concentration of wastewater influent can be realized, and the content of nitrate nitrogen in wastewater is fed back in time. The drop height, exposed reaction bed and sulfur source are dynamically regulated. This method not only can realize high load regulation, but also can realize low load regulation, so that the difference between the influent and effluent nitrate nitrogen is controlled within a certain range, which not only meets the wastewater treatment standard, but also effectively reduces the treatment cost and saves resources. It has good application prospect in actual production, thereby completing the invention.

[0011] The present application provides a kind of sulfur-based filler autotrophic denitrification filter load directional regulation method, the method includes controlling exposed bed height, adjusting drop height and adding sulfur source one or several.

[0012] The regulation method provided by the present application has the following advantages:

[0013] (1) The regulation method described in the present application can significantly reduce the nitrogen content of effluent, and improve or reduce the removal efficiency of nitrate nitrogen.

[0014] (2) The regulation method described in the present application has low operating cost and high safety.

[0015] (3) The regulation method of the application regulates in real time through online control, which is convenient and simple. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 A structure schematic diagram of a sulfur-based autotrophic denitrification fixed bed according to a preferred embodiment of the application is shown.

[0017] Figure 2 A process flow schematic diagram of a sulfur-based filler autotrophic denitrification filter directional regulation method according to a preferred embodiment of the application is shown.

[0018] EXPLANATION OF REFERENCE NUMBERS

[0019] 1 - water inlet main channel;

[0020] 2 - water inlet gate;

[0021] 3 - filter tank body;

[0022] 4 - water and air distribution system;

[0023] 6 - filter material layer;

[0024] 7 - supporting layer;

[0025] 8 - water collection channel;

[0026] 9 - water inlet channel;

[0027] 11 - filtered water outlet pipe;

[0028] 12 - air branch pipe;

[0029] 13 - water collection channel cover plate. DETAILED DESCRIPTION

[0030] The application will be described in detail below, and the features and advantages of the application will become clearer and more explicit with these descriptions.

[0031] To solve the above problems, the patent intends to study the influence of sulfur-based filler bed load influencing factors on the denitrification load of sulfur-based filler autotrophic denitrification filter, and associate it with the operating control measures such as drop height, exposed reaction bed height and sulfur source addition, to establish a method for directional regulation of denitrification load of sulfur-based filler autotrophic denitrification filter. Finally, a set of directional regulation method of denitrification load of filter type sulfur autotrophic denitrification is formed, which provides support for the advanced treatment of secondary biochemical tail water.

[0032] In the actual process of treating wastewater, the stable removal of nitrate nitrogen content is the prerequisite for realizing the stable operation of the sulfur-based filler autotrophic denitrification filter. Based on the above technical problems, the present application provides a kind of sulfur-based filler autotrophic denitrification filter load directional regulation method, which is a wastewater treatment method with feedback mode, the wastewater treatment mode can ensure that the difference between the inlet and outlet water nitrate nitrogen concentration of the treated wastewater is within a certain range. The regulation method makes the treated wastewater have a lower concentration, and can also reduce the wastewater treatment cost to the maximum extent.

[0033] The difference between the inlet and outlet water nitrate nitrogen concentration of the present application refers to the difference between the inlet and outlet water nitrate nitrogen concentration.

[0034] The present application provides a kind of sulfur-based filler autotrophic denitrification filter directional regulation method, the method includes adjusting the height of water drop, controlling the height of exposed reaction bed layer and adding sulfur source, to realize the improvement of wastewater treatment efficiency and effect, the above control method is all according to the difference between the inlet and outlet water nitrate nitrogen concentration for regulation. The method uses sulfur-based filler autotrophic denitrification filter for sewage treatment.

[0035] There is no report on the bed layer denitrification effective load regulation method in the prior art. The exposed bed layer height of the present application refers to the bed layer height of the filter material layer in the exposed denitrification filter. The bed layer height of the filter material layer refers to the height of the filled elemental sulfur or sulfur-based carrier. The percentage of the exposed bed layer height refers to the percentage of the bed layer height, which is exposed from top to bottom. The accurate control of the exposed bed layer height is realized by controlling the size of the outlet valve. The original water level height of the sulfur-based filler autotrophic denitrification filter is flush with the inlet channel 9. The water drop height refers to the vertical height from the actual water surface to the inlet channel 9. The liquid level height is controlled by adjusting the opening and closing of the outlet valve.

[0036] Adjusting the height of water drop includes increasing the height of the inlet channel 9 to the actual water surface.

[0037] The sulfur source is selected from one or more of polysulfide, thiosulfate and sulfide.

[0038] The polysulfide is selected from one or more of calcium polysulfide, magnesium polysulfide and sodium polysulfide, preferably sodium polysulfide.

[0039] The thiosulfate is selected from one or more of calcium thiosulfate, sodium thiosulfate and magnesium thiosulfate, preferably sodium thiosulfate.

[0040] The sulfide is selected from one or more of calcium sulfide, magnesium sulfide, sodium sulfide and iron sulfide, preferably sodium sulfide.

[0041] The present invention sets the target difference in nitrate nitrogen concentration between inlet and outlet water as X mg / L. During regulation, the actual difference in nitrate nitrogen concentration between inlet and outlet water, Y mg / L, is compared with the target difference in nitrate nitrogen concentration between inlet and outlet water, X, to determine one or more of adding sulfur source, controlling the drop height, or exposing the bed layer, so as to control the nitrate nitrogen reduction amount of the treated wastewater within a certain range.

[0042] The nitrate nitrogen reduction amount described in the present invention is the difference in nitrate nitrogen concentration between inlet and outlet water, referring to the difference between the inlet nitrate nitrogen concentration and the outlet nitrate nitrogen concentration. In the present invention, X is any value within 3 - 20 mg / L, preferably any value within 3 - 18 mg / L, more preferably any value within 5 - 15 mg / L. In the actual application process, generally, adjustment can be carried out within the range of adding or subtracting 2 from the X value, and the nitrate nitrogen concentration in the treated wastewater also fluctuates within a certain range, that is, within the range of adding or subtracting 2 from the X value.

[0043] The original water level height of the sulfur-based packing autotrophic denitrification filter is flush with the inlet channel 9. During the sewage treatment process, the drop height is adjusted according to the actual difference in nitrate nitrogen concentration between inlet and outlet water in the denitrification filter.

[0044] In the present invention, by setting the target difference in nitrate nitrogen concentration between inlet and outlet water, on this basis, during the later regulation, only by comparing the actual difference in nitrate nitrogen concentration between inlet and outlet water with the target difference in nitrate nitrogen concentration between inlet and outlet water, the regulation method can be determined. It is found through experiments that this method is convenient for regulating the denitrification filter, facilitating the control of the drop height, the exposed bed layer, and the addition of sulfur source, so as to control the difference in nitrate nitrogen concentration between inlet and outlet water within a certain range. In a preferred embodiment of the present invention, if the actual difference in nitrate nitrogen concentration between inlet and outlet water is lower than the set target difference (i.e., the target difference in nitrate nitrogen concentration between inlet and outlet water), wastewater treatment can be achieved by adding sulfur source. If the actual difference in nitrate nitrogen concentration between inlet and outlet water is higher than the set target difference, wastewater treatment is achieved by increasing one or both of the drop height and the exposed bed layer. If the difference in nitrate nitrogen concentration between inlet and outlet water is the same as the set value, no sulfur source is added, and the drop height and the exposed bed layer are not adjusted.

[0045] Through the above bed layer nitrogen removal effective load regulation method, regulation can be achieved in the direction of high load and also in the direction of low load. If the difference in nitrate nitrogen concentration between inlet and outlet water is greater than X mg / L, regulation towards low load is required. If the difference in nitrate nitrogen concentration between inlet and outlet water is lower than X mg / L, regulation towards high load is required.

[0046] In a further preferred embodiment of the present invention, if the actual difference in nitrate nitrogen concentration between inlet and outlet water is higher than the set target difference in nitrate nitrogen concentration between inlet and outlet water and less than or equal to A mg / L (X < Y ≤ A), the drop height is increased.

[0047] Preferably, for every 1 mg / L increase in the actual difference between the influent and effluent nitrate and nitrogen concentrations relative to the set target difference, the drop height increases by 0.01 to 0.5 m.

[0048] The value of A ranges from X to 2X, and is preferably from 1.2X to 2X.

[0049] If the actual difference in nitrate nitrogen concentration between influent and effluent exceeds the set target difference and is higher than A mg / L, increase the drop height and expose the bed layer.

[0050] Preferably, the drop height is increased to 1.5-3m. The value obtained by subtracting A from the actual difference in nitrate concentration between the influent and effluent is used. For every 1 mg / L increase in nitrate concentration, the bed exposure height is increased by 0.1-10%, until the bed exposure reaches 100% of the initial value.

[0051] For example, the actual difference in nitrate nitrogen concentration between the influent and effluent is 11 mg / L, and the target difference in nitrate nitrogen concentration between the influent and effluent is set to 6 mg / L. That is, the actual difference in nitrate nitrogen concentration between the influent and effluent is 5 mg / L higher than the target difference in nitrate nitrogen concentration between the influent and effluent, and the drop height is set to 1.2 m.

[0052] For example, the actual difference in nitrate nitrogen concentration between influent and effluent is 19 mg / L, and the target difference in nitrate nitrogen concentration between influent and effluent is set to 6 mg / L. That is, the difference in nitrate nitrogen concentration between influent and effluent is 13 mg / L higher than the set value, which is higher than A (set to 12 mg / L). The drop height is controlled at 1.5 m, and 30% of the bed is exposed.

[0053] In a further preferred embodiment of the present invention, if the actual difference in nitrate nitrogen concentration between the influent and effluent is lower than the set target difference, for every 1 mg / L reduction in nitrate nitrogen concentration compared to the set target difference, one or more of the following are added: 0.5–3 mg / L of polysulfide, 8–10 mg / L of thiosulfate, and 3–4 mg / L of sulfide. For example, if the actual difference in nitrate nitrogen concentration between the influent and effluent is 3 mg / L, and the set target difference is 6 mg / L, and the actual effluent nitrate nitrogen concentration fluctuates within the range of 6 ± 2 mg / L after treatment, that is, if the difference in nitrate nitrogen concentration between the influent and effluent is reduced by 3 mg / L relative to the set target difference, 3 mg / L of sodium polysulfide, 30 mg / L of sodium thiosulfate, or 9 mg / L of sodium sulfide are added.

[0054] The sulfur-based self-trophic denitrification filter includes an inlet 1, an inlet gate 2, a filter body 3, a water and air distribution system 4, a filter media layer 6, a support layer 7, a water collection channel 8, an inlet channel 9, and a filtered water outlet pipe 11.

[0055] The inlet 1, inlet gate 2, and inlet channel 9 are located above the filter layer 6, and the inlet 1 and inlet gate 2 are located on one side of the inlet channel 9. The inlet gate 2 is located between the inlet 1 and the inlet channel 9.

[0056] The support layer 7, the water collection channel 8, and the filter outlet pipe 11 are located below the filter media layer 6. The support layer 7 is located between the filter media layer 6 and the water collection channel 8, and the filter outlet pipe 11 is located on one side of the water collection channel 8.

[0057] The vertical distance between the water inlet channel 9 and the filter layer 6 is 0 to 3m, preferably 1.5m to 2.5m, and more preferably 1.5m to 2m.

[0058] The denitrification filter also includes an air branch pipe 12 and a water collection channel cover plate 13, which are located between the support layer 7 and the water collection channel 8.

[0059] The denitrification filter also includes a dissolved oxygen probe, a liquid level detector, a bed height monitor, an online nitrate and nitrogen monitoring device, and an inlet dosing pipe.

[0060] The inlet chemical dosing pipe is used to add sulfur source, and the online nitrate nitrogen monitoring equipment is used to monitor the nitrate nitrogen concentration in the inlet water, facilitating timely feedback of the inlet nitrate nitrogen concentration, such as... Figure 2 As shown, the bed exposure, drop height, and quality of sulfur source added to the denitrification filter are adjusted.

[0061] The inlet dosing pipe is located between the main inlet channel 1 and the inlet channel 9, above the inlet gate 2.

[0062] According to a preferred embodiment of the present invention, the filter layer 6 includes one or more of elemental sulfur, pyrite, and sulfur-based carrier, preferably including one or two of elemental sulfur and sulfur-based carrier, more preferably including elemental sulfur, and the elemental sulfur used in the present invention is spherical.

[0063] The radius of elemental sulfur is 1–15 mm, preferably 3–10 mm, and more preferably 3–6 mm.

[0064] The height of the filter media layer 6 is 1 to 5 m, preferably 1 to 4 m, and more preferably 1 to 3 m.

[0065] The porosity of the filter media layer 6 is 30% to 80%, preferably 30% to 70%, and more preferably 30% to 60%.

[0066] The filter media layer 6 also includes sulfur-autotrophic denitrifying bacteria. These bacteria can rapidly reduce nitrate nitrogen and nitrite nitrogen in the water into nitrogen gas. The filter bacteria are sulfur-autotrophic denitrifying bacteria, such as *Thiobacillus denitrifyingus*, obtained by adding sludge from a biological anoxic pond.

[0067] The material of the support layer 7 is selected from one or more of the rough-surfaced inert materials, preferably from one or more of the stones, ceramsite and pebbles, and more preferably from pebbles with a diameter of 2 to 20 mm.

[0068] The porosity of the support layer 7 is 30% to 80%, preferably 30% to 70%, and more preferably 30% to 60%. When the porosity of the support layer is within the above range, it can filter large particulate matter in the sewage and prevent large particulate matter in the sewage from entering the collection channel 8.

[0069] The biofilm formation process employs conventional techniques in the field. For example, a suitable amount of residual sludge from a wastewater treatment plant can be inoculated into the wastewater treatment system as an inoculum. Then, typical biological denitrifying bacteria are acclimated through continuous influent, allowing them to attach and grow on the surface of slow-release electron donors to form a biofilm. The surface of the slow-release electron donors is the core region (hot zone) of the biological denitrification reaction. During the acclimation process, adding decreasing amounts of dihydrogen phosphate, bicarbonate, thiosulfate, ferrous chloride, sodium chloride, magnesium sulfate, calcium chloride, and trace elements to the nitrate-containing wastewater can accelerate biofilm formation.

[0070] The time for the wastewater to be treated to flow through the denitrification fixed bed is 10 to 60 minutes, preferably 15 to 45 minutes, and more preferably 20 to 30 minutes.

[0071] The beneficial effects of this invention are as follows:

[0072] (1) The present invention can achieve both high-load regulation and low-load regulation by controlling the height of the drop, exposing the bed layer and adding sulfur source;

[0073] (2) The present invention regulates the droplet, sulfur source and exposure bed by feedback, which can effectively control the reduction of nitrate nitrogen concentration in the treated wastewater within a certain range, which not only improves the wastewater treatment effect, but also reduces the treatment cost.

[0074] (3) When the difference between the nitrate and nitrogen concentrations in the influent and effluent is higher than the set value, the denitrification load is reduced by using a cascade oxygen-enriching method or by exposing the reaction bed, thereby saving the consumption of elemental sulfur and reducing the cost of wastewater treatment.

[0075] Example

[0076] The present invention is further illustrated by specific examples below. These embodiments are only for illustrating the present invention and are not intended to limit the scope of the present invention.

[0077] Example 1

[0078] The wastewater composition is as follows: NO3-N (KNO3 added), 20 mg / L; K2HPO4·3H2O, 5 mg / L; NH4Cl, 1 mg / L; FeSO4·7H2O, 1 mg / L; NaHCO3, 60 mg / L.

[0079] The sulfur-based autotrophic denitrification filter was inoculated with 500 mL of anoxic tank sludge (sludge concentration approximately 5000 mg / L) from the Beijing Beipai Wastewater Treatment Plant. Before the formal experiment, the filter underwent microbial acclimation, followed by continuous operation with an empty bed retention time of 20 min. The influent pH was controlled at 7–8, and the reaction temperature was approximately 20℃.

[0080] The sulfur-based self-trophic denitrification filter includes an inlet 1, an inlet gate 2, a filter body 3, a water and air distribution system 4, a filter media layer 6, a support layer 7, a collection channel 8, an inlet channel 9, and a filtered outlet pipe 11. Figure 1 As shown, inlet 1, inlet gate 2, and inlet channel 9 are located above filter media layer 6. The vertical distance between inlet channel 9 and filter media layer 6 is 1.5m. Inlet 1 and inlet gate 2 are located on the same side of inlet channel 9. Inlet gate 2 is located between inlet 1 and inlet channel 9. Support layer 7, collection channel 8, and filtered water outlet and filtered water outlet pipe 11 are located below filter media layer 6. Support layer 7 is located between filter media layer 6 and collection channel 8. Filtered water outlet pipe 11 is located on one side of collection channel 8. This denitrification filter also includes air branch pipe 12 and collection channel cover plate 13. Air branch pipe 12 and collection channel cover plate 13 are located between support layer 7 and collection channel 8. The denitrification filter also includes a dissolved oxygen probe, a level gauge, a bed height monitor, an online nitrate and nitrogen monitoring device, and an inlet dosing pipe. The inlet dosing pipe is located between the inlet 1 and the inlet channel 9, above the inlet gate 2. The support layer 7 is made of 2-20mm pebbles with a porosity of 50%. The filter media layer 6 includes elemental sulfur and sulfur autotrophic denitrifying bacteria. The radius of the elemental sulfur is 3-6mm. The height of the filter media layer 6 is 1.2m, and the porosity is 41%. The target difference between influent and effluent nitrate and nitrogen concentrations is set at 6mg / L, and A is set at 12mg / L. The actual difference between influent and effluent nitrate and nitrogen concentrations is monitored to be 20mg / L. The drop height is controlled at 1.5m, exposing 40% of the bed. After adjustment, the difference between influent and effluent nitrate and nitrogen concentrations is 4-8mg / L.

[0081] Example 2

[0082] Wastewater denitrification was carried out in a manner similar to that in Example 1, except that: under the condition of an empty bed retention time of 20 min, the actual difference between influent and effluent nitrile nitrogen concentration was monitored to be 3 mg / L, and sodium thiosulfate of 30 mg / L was added to the influent. After adjustment, the difference between influent and effluent nitrile nitrogen concentration was 4-8 mg / L.

[0083] Example 3

[0084] Wastewater denitrification was carried out in a manner similar to that in Example 1, except that: under the condition of an empty bed retention time of 20 min, the actual difference between the influent and effluent nitrile nitrogen concentration was monitored to be 2 mg / L, and sodium sulfide 12 mg / L was added to the influent. After adjustment, the reduction in nitrile nitrogen concentration in the influent and effluent was 4-8 mg / L.

[0085] Example 4

[0086] Wastewater denitrification was carried out in a manner similar to that in Example 1, except that: under the condition of an empty bed retention time of 20 min, the actual difference between the influent and effluent nitrile nitrogen concentration was monitored to be 1 mg / L, and 20 mg / L of sodium sulfide was added to the influent. After adjustment, the reduction in the influent and effluent nitrile nitrogen concentration was 4-8 mg / L.

[0087] Example 5

[0088] Wastewater denitrification was carried out in a manner similar to that in Example 1, except that: under the condition of an empty bed retention time of 20 min, the actual difference between the influent and effluent nitrile nitrogen concentration was monitored to be 1 mg / L, and sodium polysulfide was added to the influent at 3 mg / L. After adjustment, the reduction in nitrile nitrogen concentration in the influent and effluent was 4-8 mg / L.

[0089] Example 6

[0090] Wastewater denitrification was carried out in a manner similar to that in Example 1, except that: under the condition of an empty bed retention time of 20 min, the actual difference between the influent and effluent nitrile nitrogen concentration was monitored to be 9 mg / L, no sulfur source was added, the drop height was increased by 1.2 m, and no bed exposure was used for regulation. After regulation, the reduction in influent and effluent nitrile nitrogen concentration was 4-8 mg / L.

[0091] Example 7

[0092] Wastewater denitrification was carried out in a manner similar to that in Example 1, except that: under the condition of an empty bed retention time of 20 min, the actual difference between the influent and effluent nitrile nitrogen concentration was monitored to be 10 mg / L, no sulfur source was added, the drop height was increased by 1.4 m, and no bed exposure was used for regulation. After regulation, the reduction in influent and effluent nitrile nitrogen concentration was 4-8 mg / L.

[0093] Example 8

[0094] Wastewater denitrification was carried out in a manner similar to that in Example 1, except that: under the condition of an empty bed retention time of 20 min, the actual difference between influent and effluent nitrile nitrogen concentration was monitored to be 13 mg / L, no sulfur source was added, the drop height was controlled to be 1.5 m, 10% of the bed was exposed, and the reduction in influent and effluent nitrile nitrogen concentration after adjustment was 4-8 mg / L.

[0095] The present invention has been described in detail above with reference to specific embodiments and exemplary examples; however, these descriptions should not be construed as limiting the present invention. Those skilled in the art will understand that various equivalent substitutions, modifications, or improvements can be made to the technical solutions and embodiments of the present invention without departing from the spirit and scope of the invention, and all such modifications and improvements fall within the scope of the present invention. The scope of protection of the present invention is defined by the appended claims.

Claims

1. A method for directional load control of a sulfur-based self-trophic denitrification filter, characterized in that, The method includes controlling one or more of the exposed bed height, regulating the drop water height, and adding a sulfur source; When the difference between the actual influent and effluent nitrate nitrogen concentrations is higher than the target difference between the influent and effluent nitrate nitrogen concentrations, increase one or both of the drop water height and the exposed bed height; when the difference between the actual influent and effluent nitrate nitrogen concentrations is lower than the set target difference between the influent and effluent nitrate nitrogen concentrations, add a sulfur source; Monitor that the difference between the actual influent and effluent nitrate nitrogen concentrations is Y mg / L, and set the target difference between the influent and effluent nitrate nitrogen concentrations as X mg / L; X is any value within 3 - 20 mg / L; When the difference between the actual influent and effluent nitrate nitrogen concentrations is higher than the set target difference between the influent and effluent nitrate nitrogen concentrations and less than or equal to A mg / L, i.e., X < Y ≤ A, increase the drop water height; the value range of A is 1.2X - 2X; For every 1 mg / L increase in the difference between the actual influent and effluent nitrate nitrogen concentrations compared to the set target difference between the influent and effluent nitrate nitrogen concentrations, the drop water height increases by 0.01 - 0.5 m; When the difference between the actual influent and effluent nitrate nitrogen concentrations is higher than the set target difference between the influent and effluent nitrate nitrogen concentrations and higher than A mg / L, i.e., Y > A, increase the drop water height and at the same time increase the exposed bed height; Increase the drop water height to 1.5 - 3 m. For every 1 mg / L increase in the difference between the actual influent and effluent nitrate nitrogen concentrations minus A mg / L, the exposed bed height increases by 0.1 - 10% until the bed is exposed to 100%; When the difference between the actual influent and effluent nitrate nitrogen concentrations is lower than the set target difference between the influent and effluent nitrate nitrogen concentrations, i.e., Y < X, add a sulfur source.

2. The method according to claim 1, characterized in that, The sulfur source is selected from one or more of polysulfide, thiosulfate, and sulfide.

3. The method according to claim 1, wherein, For every 1 mg / L decrease in the difference between the actual influent and effluent nitrate nitrogen concentrations compared to the set target difference between the influent and effluent nitrate nitrogen concentrations, add one or more of 0.5 - 3 mg / L of polysulfide, 8 - 10 mg / L of thiosulfate, and 3 - 4 mg / L of sulfide.

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