In-situ regeneration nitrogen and phosphorus removal filter material, preparation method and application

Abstract

The invention provides an in-situ regeneration nitrogen and phosphorus removal filter material as well as a preparation method and application thereof, and relates to the field of preparation of environmental functional materials. The preparation raw materials comprise an adhesive, activated carbon and ferrous sulfide. The mass ratio of the adhesive to the activated carbon to the ferrous sulfide is 20: (40-60): (20-40). According to the present invention, by using the sulfur reduction effect and the iron reduction effect of the anaerobic organisms, the added sodium sulfate is reduced into the sulfur negative ions capable of being utilized by the sulfur autotrophic denitrification microorganisms, the ferric iron is reduced into the ferrous iron, the sulfur negative ions and the ferrous iron ions are re-combined to form the ferrous sulfide, and finally the in-situ regeneration of the sulfide filtration material can be achieved.

Description

Technical Field

[0001] The present application relates to the field of preparation of environmental functional materials, and in particular to an in-situ regenerative denitrification and dephosphorization filter material, a preparation method and an application thereof. Background Art

[0002] In recent years, nitrogen pollution in surface water has become a major concern worldwide. Especially in micro-polluted surface waters with high dissolved oxygen, the carbon source is scarce due to the low level of organic pollutants. At the same time, the high content of dissolved oxygen makes it difficult to build an anoxic / anaerobic environment, which seriously hinders the denitrification reaction, and ultimately leads to the inability to effectively remove nitrate nitrogen in surface water through self-purification, making it difficult to discharge nitrogen and phosphorus in compliance with standards in this type of wastewater treatment.

[0003] In view of this situation, sulfur autotrophic denitrification technology has received widespread attention in recent years because it does not require the addition of organic carbon sources, has high nitrogen removal efficiency and good effluent quality. Sulfur autotrophic denitrification is a new type of biological denitrification technology, the principle of which is mainly mediated by sulfur autotrophic denitrifying bacteria, using inorganic sulfur compounds as electron donors to reduce nitrate or nitrite to nitrogen gas.

[0004] However, in the existing sulfur autotrophic denitrification filter, only the adjustment of the pH value of the filter material is often considered, or only the effect of enhancing the fixation or backwashing of the filter material is considered to extend the service life of the filter material. This ignores the problem that the inorganic sulfide filter material as an electron donor in the filter material will be continuously consumed as the denitrification reaction proceeds. When the filter material is consumed to a certain extent, it needs to be supplemented or replaced, which not only increases the operating cost, but also the replacement process is cumbersome and may affect the normal operation of the filter. In addition, the denitrification effect of the filter after the filter material is replaced will be weakened, and the microorganisms need to grow again to form a biofilm in order to achieve the best effect of the filter. This not only increases the time cost of denitrification, but also lacks stability in the denitrification efficiency for long-term operation systems. Summary of the invention

[0005] The purpose of the present application is to provide an in-situ regenerative denitrification and dephosphorization filter material, a preparation method and an application thereof, so as to solve the above-mentioned problems.

[0006] To achieve the above objectives, this application adopts the following technical solutions: The present application provides an in-situ regenerated denitrification and dephosphorization filter material, the preparation raw materials of which include: a binder, activated carbon, and ferrous sulfide; wherein the mass ratio of the binder, the activated carbon, and the ferrous sulfide is 20: (40-60): (20-40).

[0007] Optionally, the raw material of the binder includes polyvinyl alcohol.

[0008] The present application also provides a method for preparing an in-situ regenerated denitrification and dephosphorization filter material, the method comprising: preparing the binder; mixing and stirring the activated carbon, the ferrous sulfide, water and the binder to obtain a paste; The paste is granulated, allowed to stand, solid-liquid separated, washed and dried to obtain the in-situ regenerated denitrification and dephosphorization filter material.

[0009] Optionally, the raw materials of the binder include polyvinyl alcohol and deionized water, and the mass ratio of the polyvinyl alcohol to the deionized water is 20:(60-80).

[0010] Optionally, the mass ratio of the activated carbon, the ferrous sulfide, water and the binder is (40-60):(20-40):20:20.

[0011] Optionally, the stirring speed is 200-400 rpm and the stirring time is 60-120 minutes.

[0012] Optionally, the standing temperature is 0-5°C and the standing time is 10-15 hours.

[0013] Optionally, the drying temperature is 30-40°C.

[0014] The present application also provides a method for treating sewage using the in-situ regenerated denitrification and dephosphorization filter material, wherein the sewage is treated using the in-situ regenerated denitrification and dephosphorization filter material.

[0015] Optionally, the treatment method includes: adding the in-situ regenerated denitrification and phosphorus removal filter material to a three-stage filter system composed of multiple filter tanks, the three-stage filter system includes a primary filter tank, a secondary filter tank, and a tertiary filter tank; the treatment process includes a first cycle, a second cycle, a third cycle, and a fourth cycle.

[0016] In the first cycle, the primary filter and the secondary filter are connected in series to perform two-stage deep nitrogen and phosphorus removal, and the tertiary filter is not in operation; In the second cycle, sodium sulfate is added to the primary filter for in-situ regeneration; the secondary filter and the tertiary filter are connected in series to perform two-stage deep nitrogen and phosphorus removal; In the third cycle, sodium sulfate is added to the secondary filter for in-situ regeneration; the tertiary filter and the primary filter are connected in series to perform two-stage deep nitrogen and phosphorus removal; In the fourth cycle, sodium sulfate is added to the tertiary filter for in-situ regeneration; the primary filter and the secondary filter are connected in series to perform two-stage deep nitrogen and phosphorus removal.

[0017] Compared with the prior art, the beneficial effects of this application include: The composite autotrophic denitrification, aging and phosphorus removal filter material provided in the present application reduces the added sodium sulfate into sulfur anions that can be utilized by sulfur autotrophic denitrifying microorganisms, reduces the trivalent iron into divalent iron, and then the sulfur anions recombine with the divalent iron ions to form ferrous sulfide, thereby finally realizing the in-situ regeneration of the sulfide filter material.

[0018] The preparation method provided in the present application is simple and convenient to operate, and the raw materials are easy to obtain and of low cost, thus saving operating costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope of the present application.

[0020] Figure 1 A schematic diagram of the process flow of the in-situ regeneration denitrification and dephosphorization filter material preparation method provided in the embodiment; Figure 2 This is a physical picture of the prepared in-situ regenerated denitrification and phosphorus removal filter material. DETAILED DESCRIPTION

[0021] As used herein: "Prepared from" is synonymous with "comprising." As used herein, the terms "comprising," "including," "having," "containing," or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a composition, process, method, article, or apparatus that comprises the listed elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such composition, process, method, article, or apparatus.

[0022] The conjunction "consisting of excludes any unspecified element, step, or component. If used in a claim, this phrase renders the claim closed-ended so that it does not include materials other than those described, except for conventional impurities associated therewith. When the phrase "consisting of" appears in a clause of the body of a claim rather than immediately following the subject matter, it limits only the elements described in that clause; other elements are not excluded from the claim as a whole.

[0023] When an amount, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper preferred values ​​and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pairing of any range upper limit or preferred value with any range lower limit or preferred value, regardless of whether the range is disclosed separately. For example, when a range of "1 to 5" is disclosed, the described range should be interpreted as including ranges "1 to 4", "1 to 3", "1 to 2", "1 to 2 and 4 to 5", "1 to 3 and 5", etc. When a numerical range is described in this article, unless otherwise stated, the range is intended to include its end values ​​and all integers and fractions within the range.

[0024] In these examples, parts and percentages are by mass unless otherwise indicated.

[0025] "Mass parts" refers to the basic unit of measurement for expressing the mass ratio of multiple components. 1 part can represent any unit mass, such as 1g or 2.689g. If we say that the mass parts of component A are a parts and the mass parts of component B are b parts, it means the ratio of the mass of component A to the mass of component B is a:b. Alternatively, it means that the mass of component A is aK and the mass of component B is bK (K is an arbitrary number, indicating a multiple factor). It should not be misunderstood that, unlike the mass parts, the sum of the mass parts of all components is not limited to 100 parts.

[0026] "And / or" is used to indicate that one or both of the stated situations may occur, for example, A and / or B includes (A and B) and (A or B).

[0027] In order to better explain the technical solution provided by this application, an overall statement of the technical solution is first made before the embodiments.

[0028] In a first aspect, the present application provides an in-situ regenerated denitrification and dephosphorization filter material, the preparation raw materials of which include: a binder, activated carbon, and ferrous sulfide; wherein the mass ratio of the binder, the activated carbon, and the ferrous sulfide is 20: (40-60): (20-40).

[0029] In an optional embodiment, the raw material of the binder includes polyvinyl alcohol.

[0030] Optionally, the number of parts of the activated carbon can be 40 parts, 41 parts, 42 parts, 43 parts, 44 parts, 45 parts, 46 parts, 47 parts, 48 ​​parts, 49 parts, 50 parts, 51 parts, 52 parts, 53 parts, 54 parts, 55 parts, 56 parts, 57 parts, 58 parts, 59 parts, 60 parts, or any value between 40 and 60 parts. Optionally, the number of parts of the ferrous sulfide can be 20 parts, 21 parts, 22 parts, 23 parts, 24 parts, 25 parts, 26 parts, 27 parts, 28 parts, 29 parts, 30 parts, 31 parts, 32 parts, 33 parts, 34 parts, 35 parts, 36 parts, 37 parts, 38 parts, 39 parts, 40 parts, or any value between 20 and 40 parts. In a second aspect, the present application also provides a method for preparing an in-situ regenerated denitrification and dephosphorization filter material, the method comprising: preparing the binder; mixing and stirring the activated carbon, the ferrous sulfide, water and the binder to obtain a paste; The paste is granulated, allowed to stand, solid-liquid separated, washed and dried to obtain the in-situ regenerated denitrification and dephosphorization filter material.

[0031] In an optional embodiment, the raw materials of the binder include polyvinyl alcohol and deionized water, and the mass ratio of the polyvinyl alcohol to the deionized water is 20:(60-80).

[0032] Optionally, the mass ratio of the polyvinyl alcohol to the deionized water may be 20:60, 20:65, 20:70, 20:75, 20:80, or any value between 20:(60-80).

[0033] In an optional embodiment, the mass ratio of the activated carbon, the ferrous sulfide, water, and the binder is (40-60): (20-40): 20:20.

[0034] Optionally, in the process of preparing the in-situ regeneration denitrification and dephosphorization filter material, the amount of activated carbon added can be 40 parts, 41 parts, 42 parts, 43 parts, 44 parts, 45 parts, 46 parts, 47 parts, 48 ​​parts, 49 parts, 50 parts, 51 parts, 52 parts, 53 parts, 54 parts, 55 parts, 56 parts, 57 parts, 58 parts, 59 parts, 60 parts, or any value between 40 and 60 parts. The amount of ferrous sulfide added can be 20 parts, 21 parts, 22 parts, 23 parts, 24 parts, 25 parts, 26 parts, 27 parts, 28 parts, 29 parts, 30 parts, 31 parts, 32 parts, 33 parts, 34 parts, 35 parts, 36 parts, 37 parts, 38 parts, 39 parts, 40 parts, or any value between 20 and 40 parts.

[0035] In an optional embodiment, the stirring speed is 200-400 / min and the stirring time is 60-120 minutes.

[0036] In an optional embodiment, the standing temperature is 0-5°C and the time is 10-15 hours.

[0037] Optionally, the standing temperature may be 0°C, 1°C, 2°C, 3°C, 4°C, 5°C, or any value between 0-5°C.

[0038] In an optional embodiment, the drying temperature is 30-40°C.

[0039] In a third aspect, the present application also provides a method for treating sewage using the in-situ regenerated denitrification and dephosphorization filter material, wherein the sewage is treated using the in-situ regenerated denitrification and dephosphorization filter material.

[0040] Optionally, the treatment includes: adding the in-situ regenerated denitrification and phosphorus removal filter material to a three-stage filter system composed of multiple filter tanks, the three-stage filter system includes a primary filter tank, a secondary filter tank, and a tertiary filter tank; the treatment process includes a first cycle, a second cycle, a third cycle, and a fourth cycle.

[0041] In the first cycle, the primary filter and the secondary filter are connected in series to perform two-stage deep nitrogen and phosphorus removal, and the tertiary filter is not in operation; In the second cycle, sodium sulfate is added to the primary filter for in-situ regeneration; the secondary filter and the tertiary filter are connected in series to perform two-stage deep nitrogen and phosphorus removal; In the third cycle, sodium sulfate is added to the secondary filter for in-situ regeneration; the tertiary filter and the primary filter are connected in series to perform two-stage deep nitrogen and phosphorus removal; In the fourth cycle, sodium sulfate is added to the tertiary filter for in-situ regeneration; the primary filter and the secondary filter are connected in series to perform two-stage deep nitrogen and phosphorus removal.

[0042] It is understandable that in the technical solution of the present application: the activated carbon mainly plays the role of adsorbing pollutants in the water. Ferrous sulfide is mainly responsible for providing a sulfur source for sulfur autotrophic denitrifying microorganisms to carry out deep denitrification and phosphorus removal. The main function of the binder is to enhance the molding of the filter material, improve the performance, and improve the overall stability of the filter material. In the three-stage filtration system of the present invention, the strategy of "two-stage deep treatment coupled with single-stage regeneration" is adopted, that is, by systematically controlling the switching status of each valve, there are always two filters in the filter system in a working state, and the remaining one is regenerated. The present application utilizes the sulfur-reducing and iron-reducing effects of anaerobic organisms to reduce the added sodium sulfate into sulfur anions that can be utilized by sulfur-autotrophic denitrifying microorganisms, and reduces trivalent iron into divalent iron, and then the sulfur anions recombine with the divalent iron ions to form ferrous sulfide, thereby ultimately achieving in-situ regeneration of the sulfide filter material. Through systematic and dynamic regulation of the valves in the three-stage filter system, the regenerated filter material can be circulated into the filter system to participate in deep denitrification and phosphorus removal, thereby not only avoiding the problem of filter material failure requiring replacement, but also eliminating the process of restarting the biofilm and waiting for microbial biofilm growth, which not only saves operating costs but also ensures the stable operation of the filtration system.

[0043] The embodiments of the present application will be described in detail below in conjunction with specific examples, but it will be appreciated by those skilled in the art that the following examples are only used to illustrate the present application and should not be considered as limiting the scope of the present application. If specific conditions are not specified in the examples, they are carried out according to normal conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified in the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0044] Example 1 This embodiment provides a method for preparing an in-situ regeneration denitrification and dephosphorization filter material. The preparation process is as follows: Figure 1 As shown, the specific steps are as follows: 100 g of polyvinyl alcohol was added to 350 g of deionized water, and the mixture was stirred at a speed of 120 r / min for 1 hour using a magnetic stirrer to obtain a binder; 250 g of activated carbon and 150 g of ferrous sulfide powder were added to 100 g of deionized water, and 100 g of a binder was added. The mixture was stirred for 1 hour at a speed of 300 r / min using a magnetic stirrer to obtain a paste. The paste was then poured into a mold with a pore size of 4 mm for granulation. The mixture was allowed to stand at 5°C for 10 hours, filtered and washed thoroughly, and spherical particles with a diameter of 4 mm were formed in the grooves of the mold. The mixture was aged and dried at 35°C in a dryer to obtain an in-situ regenerated denitrification and dephosphorization filter material. The obtained in-situ regenerated denitrification and dephosphorization filter material is as follows: Figure 2 shown.

[0045] This embodiment also provides a method for treating sewage by in-situ regeneration of denitrification and dephosphorization filter material, and the specific steps are as follows: The in-situ regeneration denitrification and dephosphorization filter material prepared by the above method was added to three 10L CSTR continuous flow reactors to conduct deep denitrification and dephosphorization experiments. The experimental model adopted a three-stage filter system.

[0046] In the first cycle (days 1-30), the primary filter and the secondary filter were connected in series to conduct a two-stage deep nitrogen and phosphorus removal experiment, and the tertiary filter was not in operation.

[0047] In the second cycle (days 31-60), sodium sulfate was added to the primary filter for regeneration, and the secondary and tertiary filters were connected in series to conduct a two-stage deep nitrogen and phosphorus removal experiment.

[0048] In the third cycle (days 61-90), sodium sulfate was added to the second filter for regeneration, and the third filter and the first filter were connected in series to conduct a two-stage deep nitrogen and phosphorus removal experiment.

[0049] In the fourth cycle (91-120 days), sodium sulfate was added to the tertiary filter for regeneration, and the primary filter and the secondary filter that had completed in-situ regeneration were connected in series to carry out a two-stage deep nitrogen and phosphorus removal experiment.

[0050] The influent during the experiment was taken from the effluent of the aerobic pool of the actual sewage plant, and the influent flow rate was 40L / d, so the hydraulic retention time of the system was 12 hours. During the experiment, samples were taken every two days to test various indicators in the effluent.

[0051] Example 2 This embodiment provides a method for preparing an in-situ regeneration denitrification and dephosphorization filter material, and the specific steps are as follows: 100 g of polyvinyl alcohol was added to 350 g of deionized water, and the mixture was stirred at a speed of 120 r / min for 1 hour using a magnetic stirrer to obtain a binder; 300 g of activated carbon and 100 g of ferrous sulfide powder were added to 100 g of deionized water, and 100 g of a binder was added. The mixture was stirred for 1 hour at a speed of 300 r / min using a magnetic stirrer to obtain a paste. The paste was then poured into a mold with a pore size of 4 mm for granulation. The mixture was allowed to stand at 5°C for 10 hours, filtered and washed thoroughly, and spherical particles with a diameter of 4 mm were formed in the grooves of the mold. The mixture was aged and dried at 35°C using a dryer to obtain an in-situ regenerated denitrification and dephosphorization filter material.

[0052] This embodiment also provides a method for treating sewage by in-situ regeneration of denitrification and dephosphorization filter material, and the specific steps are as follows: The in-situ regeneration denitrification and dephosphorization filter material prepared by the above method was added to three 10L CSTR continuous flow reactors to conduct deep denitrification and dephosphorization experiments. The experimental model adopted a three-stage filter system.

[0053] In the first cycle (days 1-30), the primary filter and the secondary filter were connected in series to conduct a two-stage deep nitrogen and phosphorus removal experiment, and the tertiary filter was not in operation.

[0054] In the second cycle (days 31-60), sodium sulfate was added to the primary filter for regeneration, and the secondary and tertiary filters were connected in series to conduct a two-stage deep nitrogen and phosphorus removal experiment.

[0055] In the third cycle (days 61-90), sodium sulfate was added to the second filter for regeneration, and the third filter and the first filter were connected in series to conduct a two-stage deep nitrogen and phosphorus removal experiment.

[0056] In the fourth cycle (91-120 days), sodium sulfate was added to the tertiary filter for regeneration, and the primary filter and the secondary filter that had completed in-situ regeneration were connected in series to carry out a two-stage deep nitrogen and phosphorus removal experiment.

[0057] The influent during the experiment was taken from the effluent of the aerobic pool of the actual sewage plant, and the influent flow rate was 40L / d, so the hydraulic retention time of the system was 12 hours. During the experiment, samples were taken every two days to test various indicators in the effluent.

[0058] Example 3 This embodiment provides a method for preparing an in-situ regeneration denitrification and dephosphorization filter material, and the specific steps are as follows: 100 g of polyvinyl alcohol was added to 350 g of deionized water, and the mixture was stirred at a speed of 120 r / min for 1 hour using a magnetic stirrer to obtain a binder; 200 g of activated carbon and 200 g of ferrous sulfide powder were added to 100 g of deionized water, and 100 g of binder was added. The mixture was stirred for 1 hour at a speed of 300 r / min using magnetic stirring to obtain a paste. The paste was then poured into a mold with a pore size of 4 mm for granulation, and allowed to stand at 5°C for 10 hours. The mixture was filtered and washed thoroughly, and spherical particles with a diameter of 4 mm were formed in the grooves of the mold. The mixture was aged and dried at 35°C using a dryer to obtain an in-situ regenerated denitrification and dephosphorization filter material.

[0059] This embodiment also provides a method for treating sewage by in-situ regeneration of denitrification and dephosphorization filter material, and the specific steps are as follows: The in-situ regeneration denitrification and dephosphorization filter material prepared by the above method was added to three 10L CSTR continuous flow reactors to conduct deep denitrification and dephosphorization experiments. The experimental model adopted a three-stage filter system.

[0060] In the first cycle (days 1-30), the primary filter and the secondary filter were connected in series to conduct a two-stage deep nitrogen and phosphorus removal experiment, and the tertiary filter was not in operation.

[0061] In the second cycle (days 31-60), sodium sulfate was added to the primary filter for regeneration, and the secondary and tertiary filters were connected in series to conduct a two-stage deep nitrogen and phosphorus removal experiment.

[0062] In the third cycle (days 61-90), sodium sulfate was added to the second filter for regeneration, and the third filter and the first filter were connected in series to conduct a two-stage deep nitrogen and phosphorus removal experiment.

[0063] In the fourth cycle (91-120 days), sodium sulfate was added to the tertiary filter for regeneration, and the primary filter and the secondary filter that had completed in-situ regeneration were connected in series to carry out a two-stage deep nitrogen and phosphorus removal experiment.

[0064] The influent during the experiment was taken from the effluent of the aerobic pool of the actual sewage plant, and the influent flow rate was 40L / d, so the hydraulic retention time of the system was 12 hours. During the experiment, samples were taken every two days to test various indicators in the effluent.

[0065] Comparative Example 1 This comparative example provides a method for treating sewage in a single-stage filter system, and the specific steps are as follows: The activated carbon coupled with ferrous sulfide filler prepared by the method in Example 1 was added to a 20 L CSTR continuous flow reactor for long-term nitrogen and phosphorus removal experiments. The influent during the experiment was taken from the effluent of the aerobic pool of an actual sewage plant, and the influent flow rate was 40 L / d, so the hydraulic retention time of the system was 12 hours. The experimental mode adopted an ordinary single-stage filter system, without regenerating ferrous sulfide, sampling once every two days, and detecting various indicators in the effluent.

[0066] Comparative Example 2 This comparative example provides a method for treating sewage using activated carbon alone, and the specific steps are as follows: 100 parts of activated carbon were added to a 20L CSTR continuous flow reactor for long-term nitrogen and phosphorus removal experiments. The influent in the experiment was taken from the effluent of the aerobic pool of the actual sewage plant, and the influent flow rate was 40 L / d, so the hydraulic retention time of the system was 12 hours. The experimental mode adopted an ordinary single-stage filter system, sampling once every two days to detect various indicators in the effluent.

[0067] Comparative Example 3 This comparative example provides a conventional method for preparing a denitrification and dephosphorization filter material, and the specific steps are as follows: 100 g of polyvinyl alcohol was added to 350 g of deionized water, and the mixture was stirred at a speed of 120 r / min for 1 hour using a magnetic stirrer to obtain a binder; 200 g of sulfur and 200 g of pyrite were crushed, sieved and added to 100 g of deionized water, 100 g of binder, and stirred for 1 hour at a speed of 300 r / min using magnetic stirring to obtain a paste, which was then poured into a mold with a pore size of 4 mm for granulation, allowed to stand at 5°C (0-5) for 10 hours, filtered and fully washed, and spherical particles with a diameter of 4 mm were formed in the grooves of the mold. After aging and drying at 35°C in a dryer, conventional denitrification and dephosphorization filter material was obtained.

[0068] This comparative example also provides a method for treating sewage using the above-mentioned denitrification and dephosphorization filter material, and the specific steps are as follows: The in-situ regeneration denitrification and dephosphorization filter material prepared by the above method was added to three 10L CSTR continuous flow reactors to conduct deep denitrification and dephosphorization experiments. The experimental model adopted a three-stage filter system.

[0069] In the first cycle (days 1-30), the primary filter and the secondary filter were connected in series to conduct a two-stage deep nitrogen and phosphorus removal experiment, and the tertiary filter was not in operation.

[0070] In the second cycle (days 31-60), sodium sulfate was added to the primary filter for regeneration, and the secondary and tertiary filters were connected in series to conduct a two-stage deep nitrogen and phosphorus removal experiment.

[0071] In the third cycle (days 61-90), sodium sulfate was added to the second filter for regeneration, and the third filter and the first filter were connected in series to conduct a two-stage deep nitrogen and phosphorus removal experiment.

[0072] In the fourth cycle (91-120 days), sodium sulfate was added to the tertiary filter for regeneration, and the primary filter and the secondary filter that had completed in-situ regeneration were connected in series to carry out a two-stage deep nitrogen and phosphorus removal experiment.

[0073] The influent during the experiment was taken from the effluent of the aerobic pool of the actual sewage plant, and the influent flow rate was 40L / d, so the hydraulic retention time of the system was 12 hours. During the experiment, samples were taken every two days to test various indicators in the effluent.

[0074] The values ​​of various indicators after sewage treatment in the above embodiments and comparative examples are shown in Table 1: Table 1 Various indicators after sewage treatment in the embodiments and comparative examples

[0075] As can be seen from Table 1, the three-stage filter system provided by the present application has better denitrification and phosphorus removal effects than the single-stage filtration system. At the same time, the in-situ regenerable denitrification and phosphorus removal filter material used in the present application has better denitrification and phosphorus removal effects than conventional denitrification and phosphorus removal filter materials and activated carbon used alone. Compared with the prior art, the present application mainly uses the systematic dynamic regulation of valves in the three-stage filter system. On the one hand, the filter material in the filter can be continuously regenerated in a low-cost form, and circulated into the filter system to participate in deep denitrification and phosphorus removal, avoiding the problem of filter material failure and the need to replace the filter material, saving the cost of operation. On the other hand, it can always have two stably operating filter tanks in the system for double-stage deep denitrification and phosphorus removal, eliminating the process of restarting the biofilm after replacing the filter material and waiting for the growth of microbial biofilm, ensuring the stable operation effect and effluent water quality of the filtration system.

[0076] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

[0077] In addition, those skilled in the art will appreciate that, although some embodiments herein include certain features included in other embodiments but not other features, the combination of features of different embodiments is meant to be within the scope of the present application and form different embodiments. For example, in the above claims, any one of the claimed embodiments may be used in any combination. The information disclosed in this background technology section is intended only to deepen the understanding of the overall background technology of the present application and should not be regarded as an admission or in any form of implication that the information constitutes prior art known to those skilled in the art.

Claims

1. An in-situ regeneration denitrification and dephosphorization filter material, characterized in that: The preparation raw materials include: a binder, activated carbon, and ferrous sulfide; the mass ratio of the binder, the activated carbon, and the ferrous sulfide is 20: (40-60): (20-40).

2. The in-situ regeneration denitrification and dephosphorization filter material according to claim 1, characterized in that: The raw material of the binder includes polyvinyl alcohol.

3. A method for preparing an in-situ regeneration denitrification and dephosphorization filter material according to claim 1 or 2, characterized in that: include: preparing the binder; mixing and stirring the activated carbon, the ferrous sulfide, water and the binder to obtain a paste; The paste is granulated, allowed to stand, solid-liquid separated, washed and dried to obtain the in-situ regenerated denitrification and dephosphorization filter material.

4. The method for preparing the in-situ regeneration denitrification and dephosphorization filter material according to claim 3, characterized in that: The raw materials of the adhesive include polyvinyl alcohol and deionized water, and the mass ratio of the polyvinyl alcohol to the deionized water is 20:(60-80).

5. The method for preparing the in-situ regeneration denitrification and dephosphorization filter material according to claim 4, characterized in that: The mass ratio of the activated carbon, the ferrous sulfide, water and the binder is (40-60):(20-40):20:

20.

6. The method for preparing the in-situ regeneration denitrification and dephosphorization filter material according to claim 3, characterized in that: The stirring speed is 200-400 rpm and the stirring time is 60-120 minutes.

7. The method for preparing the in-situ regeneration denitrification and dephosphorization filter material according to claim 3, characterized in that: The standing temperature is 0-5°C and the standing time is 10-15 hours.

8. The method for preparing the in-situ regeneration denitrification and dephosphorization filter material according to any one of claims 3 to 7, characterized in that: The drying temperature is 30-40°C.

9. A method for treating sewage using the in-situ regenerated denitrification and dephosphorization filter material according to claim 1 or 2, characterized in that: The sewage is treated using the in-situ regenerated denitrification and dephosphorization filter material.

10. The method for treating sewage by in-situ regeneration of denitrification and dephosphorization filter material according to claim 9, characterized in that: The processing includes: The in-situ regenerated denitrification and dephosphorization filter material is added to a three-stage filter system composed of multiple filter tanks, wherein the three-stage filter system includes a primary filter tank, a secondary filter tank, and a tertiary filter tank; the treatment process includes a first cycle, a second cycle, a third cycle, and a fourth cycle; In the first cycle, the primary filter and the secondary filter are connected in series to perform two-stage deep nitrogen and phosphorus removal, and the tertiary filter is not in operation; In the second cycle, sodium sulfate is added to the primary filter for in-situ regeneration; the secondary filter and the tertiary filter are connected in series to perform two-stage deep nitrogen and phosphorus removal; In the third cycle, sodium sulfate is added to the secondary filter for in-situ regeneration; the tertiary filter and the primary filter are connected in series to perform two-stage deep nitrogen and phosphorus removal; In the fourth cycle, sodium sulfate is added to the tertiary filter for in-situ regeneration; the primary filter and the secondary filter are connected in series to perform two-stage deep nitrogen and phosphorus removal.

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