Sulfur autotrophic denitrification filler and preparation method thereof

Abstract

The present invention provides a sulfur autotrophic denitrification filler and a preparation method thereof. The sulfur autotrophic denitrification filler of the present invention comprises the following raw materials in parts by weight: 50-100 parts of sulfur powder, 5-20 parts of pH buffer, 10-50 parts of medical stone, and 0-10 parts of additives; wherein the pH buffer is one or more of sodium carbonate, sodium bicarbonate, sodium hydroxide, and potassium hydroxide; and the additive is one or more of amide substances and epoxy resins. The sulfur autotrophic denitrification filler has good filler strength and a long service life, and can be conducive to the attachment of denitrifying thiobacillus to the surface of the sulfur autotrophic denitrification filler, thereby increasing the microbial concentration per unit volume of the filler and increasing the reaction rate.

Description

Technical Field

[0001] The invention relates to the technical field of sewage treatment, in particular to a sulfur autotrophic denitrification filler and a preparation method thereof. Background Art

[0002] Nitrogen pollution is an important part of water environment management. In order to ensure the stability of the water ecological environment and avoid water deterioration, the wastewater generated by industrial enterprises needs to be discharged after denitrification treatment. At present, heterotrophic denitrification process is the most commonly used denitrification method, that is, denitrifying bacteria use organic matter as an electron donor to reduce nitrate nitrogen to nitrogen gas under anaerobic conditions. Carbon sources are continuously consumed during heterotrophic denitrification. Therefore, it is necessary to add carbon sources during operation. Insufficient addition of carbon sources will lead to incomplete denitrification, and excessive addition of carbon sources may cause excessive organic matter. Excessive carbon sources are converted into sludge and discharged, resulting in large sludge production. In addition, the addition of carbon sources also increases operating costs.

[0003] To overcome the above problems, sulfur autotrophic denitrification is one of the best ways to replace the traditional heterotrophic denitrification process. Sulfur autotrophic denitrification technology is a process that uses reduced sulfide as an electron donor to reduce nitrate nitrogen (NO3-N) or nitrite nitrogen (NO2-N) to nitrogen (N2). It is suitable for treating nitrogen-contaminated wastewater. Compared with traditional denitrification, sulfur autotrophic denitrification technology uses autotrophic denitrification fillers to construct an autotrophic denitrification system. It can efficiently remove total nitrogen from sewage without adding a carbon source, reducing the risk of excessive organic matter. At the same time, the backwash cycle is long, which can effectively reduce the amount of sludge discharged.

[0004] Sulfur autotrophic denitrification fillers usually include sulfur and inorganic carbon sources. During the denitrification reaction, sulfur is used as an electron donor and inorganic carbon sources are used as energy sources. In an anaerobic environment, denitrifying Thiobacillus can reduce NO3-N to N2. The chemical reaction equation is:

[0005] 1.143S 0 +NO3 – +0.337CO2+0.0842NH4 + +0.699H2O→0.5N2+1.1143SO4 2- +1.228H + +0.0842C5H7O2N 0

[0006] However, due to the low attachment rate of denitrifying Thiobacillus on the surface of sulfur autotrophic denitrification filler, the reaction rate is low and the filler strength is weak. Under the impact of water flow such as backwashing, it is easy to cause filler loss and increase operating costs. Summary of the invention

[0007] The object of the present invention is to provide a sulfur autotrophic denitrification filler to solve the problems of high loss and low reaction rate of sulfur autotrophic denitrification fillers in the prior art.

[0008] In order to solve the above technical problems, the technical solution of the present invention is as follows:

[0009] A sulfur autotrophic denitrification filler comprises the following raw materials in parts by weight: 50 to 100 parts of sulfur powder, 5 to 20 parts of pH buffer, 10 to 50 parts of medical stone, and 0 to 10 parts of additives;

[0010] Wherein, the pH buffer is one or more of sodium carbonate, sodium bicarbonate, sodium hydroxide, and potassium hydroxide; and the additive is one or more of amide substances and epoxy resins.

[0011] Preferably, the additive is 1 to 10 parts.

[0012] Preferably, the amide substance is one or more of polyacrylamide and propionamide.

[0013] Preferably, the additive is a mixture of polyacrylamide, propionamide and epoxy resin in a weight ratio of 3:1:5.

[0014] Preferably, the sulfur autotrophic denitrification filler further comprises a binder; the binder is one or more of SBS and SBR.

[0015] The SBS refers to a styrene-butadiene-styrene block copolymer, including two molecular configurations: star-shaped and linear. In the present invention, it refers to a linear block copolymer SBS.

[0016] The SBR refers to styrene-butadiene rubber, also known as polystyrene butadiene copolymer, with a CAS number of 9003-55-8.

[0017] Preferably, the amount of the adhesive is 5 to 20 parts.

[0018] Preferably, the sulfur autotrophic denitrification filler comprises the following raw materials in parts by weight: 60 parts of sulfur powder, 15 parts of pH buffer, 20 parts of medical stone, 15 parts of adhesive, and 10 parts of additive.

[0019] The present invention also provides a method for preparing a sulfur autotrophic denitrification filler, comprising the following steps:

[0020] (1) taking sulphur powder, pH buffer, medical stone and additives by weight, mixing them uniformly to obtain a mixed raw material;

[0021] (2) uniformly mixing the mixed raw material obtained in step (1) with water to obtain a slurry;

[0022] (3) granulating the slurry obtained in step (2), drying and cooling.

[0023] Preferably, in step (2), the weight ratio of the mixed raw material to water is 1:(0.3-2).

[0024] Preferably, in step (3), the drying temperature is 60-70° C., and the drying time is 6-12 hours.

[0025] Preferably, in step (3), the particle size of the granulation is 2 to 5 mm.

[0026] The above solution of the present invention includes at least the following beneficial effects:

[0027] (1) The sulfur autotrophic denitrification filler of the present invention comprises the following raw materials in parts by weight: 50-100 parts of sulfur powder, 5-20 parts of pH buffer, 10-50 parts of medical stone, and 0-10 parts of additives; wherein the pH buffer is one or more of sodium carbonate, sodium bicarbonate, sodium hydroxide, and potassium hydroxide; and the additive is one or more of amide substances and epoxy resins. The sulfur autotrophic denitrification filler has good filler strength and a long service life, and can facilitate the attachment of denitrifying thiobacillus to the surface of the sulfur autotrophic denitrification filler, increase the microbial concentration per unit volume of filler, and increase the reaction rate.

[0028] During the denitrification reaction of the sulfur autotrophic denitrification filler, the denitrifying Thiobacillus uses the sulfur powder as an electron donor and the inorganic carbon source CO2 as an energy source to convert nitrate nitrogen into nitrogen gas;

[0029] Since denitrification is the reaction that produces H + As the reaction proceeds, more and more H + , causing changes in the pH of the system, resulting in reduced activity of microorganisms, while the pH buffer can neutralize the H produced by the denitrification reaction. + , thereby ensuring that the system maintains pH balance. In particular, when sodium carbonate and sodium bicarbonate are used as pH buffers, the CO2 produced by the neutralization reaction provides a carbon source for the denitrification reaction, ensuring the denitrification effect;

[0030] The additive amide substances and epoxy resins can undergo cross-linking reactions under alkaline conditions to generate a three-dimensional network structure, strengthen the strength of the filler, reduce the loss of filler caused by water flow impact such as backwashing, and ensure the stable operation of the system. More importantly, the polyacrylamide contains surface active groups, which can fix microorganisms on the surface of the filler through chemical bonds, thereby increasing the microbial concentration per unit volume of filler and increasing the reaction rate. The propionamide can adjust the cross-linking structure of polyacrylamide and epoxy resin, and can also provide an active group amide group, which synergistically improves the fixation effect of microorganisms with the polyacrylamide, thereby increasing the microbial concentration and reaction rate.

[0031] (2) The sulfur autotrophic denitrification filler of the present invention further includes a binder; the binder is one or more of SBS and SBR. The sulfur autotrophic denitrification filler uses the medical stone as a carrier and has high strength. By adding the binder, the strength of the filler can be further improved, and the filler loss caused by water flow impact such as backwashing can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram of the structure of the processing device used in the experimental example of the effect of the present invention. DETAILED DESCRIPTION

[0033] In the embodiments of the present invention, if the specific conditions are not specified, the conventional conditions or the conditions recommended by the manufacturer are followed. If the manufacturer of the reagents or instruments is not specified, they are all conventional products that can be purchased commercially. Raw materials of different manufacturers and models do not affect the implementation of the technical solution of the present invention and the realization of the technical effects.

[0034] Example 1

[0035] The sulfur autotrophic denitrification filler in this embodiment includes the following raw materials in parts by weight:

[0036] 50 parts of sulfur powder, 15 parts of pH buffer, 10 parts of medical stone, and 5 parts of additives.

[0037] Wherein, the pH buffer is sodium carbonate; and the additive is polyacrylamide.

[0038] The preparation method of the sulfur autotrophic denitrification filler described in this embodiment comprises the following steps:

[0039] (1) taking sulphur powder, pH buffer, medical stone and additives by weight, mixing them uniformly to obtain a mixed raw material;

[0040] (2) mixing the mixed raw material obtained in step (1) and water in a weight ratio of 1:0.3 to obtain a slurry;

[0041] (3) The slurry obtained in step (2) is granulated using a granulator to obtain particles with a particle size of 2 to 5 mm, and the obtained particles are then dried at 70° C. for 6 hours and cooled.

[0042] Example 2

[0043] The sulfur autotrophic denitrification filler in this embodiment includes the following raw materials in parts by weight:

[0044] 100 parts of sulfur powder, 10 parts of pH buffer, 50 parts of medical stone, and 7 parts of additives.

[0045] Wherein, the pH buffer is sodium bicarbonate; and the additive is epoxy resin.

[0046] The preparation method of the sulfur autotrophic denitrification filler described in this embodiment comprises the following steps:

[0047] (1) taking sulphur powder, pH buffer, medical stone and additives by weight, mixing them uniformly to obtain a mixed raw material;

[0048] (2) mixing the mixed raw material obtained in step (1) and water in a weight ratio of 1:2 to obtain a slurry;

[0049] (3) Granulating the slurry obtained in step (2) to obtain particles with a particle size of 2 to 5 mm, drying the obtained particles at 65° C. for 8 h, and cooling.

[0050] Example 3

[0051] The sulfur autotrophic denitrification filler in this embodiment includes the following raw materials in parts by weight:

[0052] 80 parts of sulfur powder, 20 parts of pH buffer, 20 parts of medical stone, 10 parts of additives, and 5 parts of adhesive.

[0053] Wherein, the pH buffer is sodium hydroxide; the additive is propionamide; and the adhesive is SBS.

[0054] The preparation method of the sulfur autotrophic denitrification filler described in this embodiment comprises the following steps:

[0055] (1) taking sulphur powder, pH buffer, medical stone and additives by weight, mixing them uniformly to obtain a mixed raw material;

[0056] (2) mixing the mixed raw material obtained in step (1) and water in a weight ratio of 1:1.5 to obtain a slurry;

[0057] (3) The slurry obtained in step (2) is granulated using a granulator to obtain particles with a particle size of 2 to 5 mm, and the obtained particles are then dried at 70° C. for 12 h and cooled.

[0058] Example 4

[0059] The sulfur autotrophic denitrification filler in this embodiment includes the following raw materials in parts by weight:

[0060] 70 parts of sulfur powder, 5 parts of pH buffer, 30 parts of medical stone, 1 part of additives, and 20 parts of adhesives.

[0061] Wherein, the pH buffer is potassium hydroxide; the additive is a mixture of polyacrylamide and epoxy resin in a weight ratio of 1:1; and the adhesive is SBR.

[0062] The preparation method of the sulfur autotrophic denitrification filler described in this embodiment comprises the following steps:

[0063] (1) taking sulphur powder, pH buffer, medical stone and additives by weight, mixing them uniformly to obtain a mixed raw material;

[0064] (2) mixing the mixed raw material obtained in step (1) and water in a weight ratio of 1:1 to obtain a slurry;

[0065] (3) Granulating the slurry obtained in step (2) to obtain particles with a particle size of 2 to 5 mm, drying the obtained particles at 60° C. for 10 h, and cooling.

[0066] Example 5

[0067] The sulfur autotrophic denitrification filler in this embodiment includes the following raw materials in parts by weight:

[0068] 60 parts of sulfur powder, 15 parts of pH buffer, 20 parts of medical stone, 10 parts of additives, and 15 parts of adhesives.

[0069] Wherein, the pH buffer is sodium bicarbonate; the additive is a mixture of polyacrylamide, propionamide and epoxy resin in a weight ratio of 1:1:1; and the adhesive is SBS.

[0070] The preparation method of the sulfur autotrophic denitrification filler described in this embodiment comprises the following steps:

[0071] (1) taking sulphur powder, pH buffer, medical stone and additives by weight, mixing them uniformly to obtain a mixed raw material;

[0072] (2) mixing the mixed raw material obtained in step (1) and water in a weight ratio of 1:0.8 to obtain a slurry;

[0073] (3) Granulating the slurry obtained in step (2) to obtain particles with a particle size of 2 to 5 mm, drying the obtained particles at 65° C. for 8 h, and cooling.

[0074] Example 6

[0075] The sulfur autotrophic denitrification filler of this embodiment has the same raw materials as those of Embodiment 5 and is prepared by the same method, with the only difference being that the additive is a mixture of polyacrylamide, propionamide, and epoxy resin in a weight ratio of 3:1:5.

[0076] Example 7

[0077] The sulfur autotrophic denitrification filler of this embodiment has the same raw materials as those of Embodiment 5 and is prepared by the same method, with the only difference being that the additive is polyacrylamide.

[0078] Example 8

[0079] The sulfur autotrophic denitrification filler of this embodiment has the same raw materials as those of Embodiment 5 and is prepared by the same method, with the only difference being that the additive is propionamide.

[0080] Example 9

[0081] The sulfur autotrophic denitrification filler of this embodiment has the same raw materials as those of Embodiment 5 and is prepared by the same method, with the only difference being that the additive is epoxy resin.

[0082] Example 10

[0083] The sulfur autotrophic denitrification filler of this embodiment has the same raw materials as those of Embodiment 5 and is prepared by the same method, with the only difference being that it does not contain a binder.

[0084] Comparative Example 1

[0085] The sulfur autotrophic denitrification filler of this comparative example has the same raw materials as those of Example 5 and is prepared by the same method, with the only difference being that it does not contain a pH buffer.

[0086] Comparative Example 2

[0087] The sulfur autotrophic denitrification filler of this comparative example has the same raw materials as those of Example 5 and is prepared by the same method, with the only difference being that it does not contain additives.

[0088] Effect experiment example

[0089] In order to verify the technical effect of the sulfur autotrophic denitrification filler described in the present invention, the following experiments were conducted:

[0090] 100L of sulfur autotrophic denitrification fillers in Examples 1-10 and Comparative Examples 1-2 were used to treat the secondary biochemical effluent of a chemical enterprise. After measurement, the initial total nitrogen content of the secondary biochemical effluent was 65mg / L and the pH was 7.5. The same treatment device and the same residence time were used to conduct the test, observe the total nitrogen removal effect and water quality changes, and record the average total nitrogen and pH value of the effluent. Figure 1 As shown, the secondary biochemical effluent enters the reaction tank from the water tank through the water inlet lift pump, and then flows out after being denitrified by the sulfur autotrophic denitrification filler in the reaction tank.

[0091] 50 mL of the filler on the 20th day of the treatment process was taken to determine the concentration of Thiobacillus denitrificans therein and to measure the filler strength.

[0092] After experimentation, the results are as follows:

[0093] Table 1 Average value of total nitrogen in effluent

[0094]

[0095] Table 2 pH value

[0096]

[0097]

[0098] Table 3 Denitrifying Thiobacillus concentration and filler strength

[0099]

[0100] According to the comparison between Examples 1-10 and Comparative Examples 1-2, the sulfur autotrophic denitrification filler of the present invention can effectively remove total nitrogen in sewage, has good filler strength, and has a long service life.

[0101] According to the comparison between Examples 1-10 and Comparative Example 1, the sulfur autotrophic denitrification filler added with the pH buffer can maintain the pH balance of the reaction system, thereby extending its service life.

[0102] According to the comparison between Examples 5-10 and Examples 1-3, it can be seen that when the additives are polyacrylamide, propionamide, and epoxy resin, they can synergistically enhance the strength of the filler and fix the microorganisms, which is more conducive to the attachment of denitrifying Thiobacillus to the surface of the sulfur autotrophic denitrification filler, and the microbial concentration per unit volume of the filler is significantly improved; in particular, in Example 6, when the additives are polyacrylamide, propionamide, and epoxy resin mixed in a weight ratio of 3:1:5, the cross-linked structure of polyacrylamide and epoxy resin adjusted by propionamide is more conducive to the function of the filler, and the denitrification effect is the best and the overall performance is the best.

[0103] According to the comparison between Example 5 and Comparative Example 2, the sulfur autotrophic denitrification filler added with the binder has higher strength, can maintain a good denitrification effect for a longer period of time, and has a longer service life.

[0104] It is known from common technical knowledge that the present invention can be implemented by other embodiments that do not deviate from its spirit or essential features. Therefore, the above disclosed embodiments are only illustrative in all respects and are not exclusive. All changes within the scope of the present invention or within the scope equivalent to the present invention are included in the present invention.

Claims

1. A sulfur autotrophic denitrification filler, characterized in that: The method comprises the following raw materials in parts by weight: 60 parts of sulfur powder, 15 parts of pH buffer, 20 parts of medical stone, 15 parts of adhesive, and 10 parts of additive; Wherein, the pH buffer is sodium bicarbonate; the additive is a mixture of polyacrylamide, propionamide and epoxy resin in a weight ratio of 3:1:5; and the adhesive is SBS.

2. A method for preparing the sulfur autotrophic denitrification filler according to claim 1, characterized in that: The steps include: (1) taking sulphur powder, pH buffer, medical stone and additives by weight, mixing them uniformly to obtain a mixed raw material; (2) uniformly mixing the mixed raw material obtained in step (1) with water to obtain a slurry; (3) granulating the slurry obtained in step (2), drying and cooling.

3. The method for preparing the sulfur autotrophic denitrification filler according to claim 2, characterized in that: In step (2), the weight ratio of the mixed raw material to water is 1:(0.3-2).

4. The method for preparing the sulfur autotrophic denitrification filler according to claim 2, characterized in that: In step (3), the drying temperature is 60-70° C. and the drying time is 6-12 hours.

5. The method for preparing the sulfur autotrophic denitrification filler according to claim 2, characterized in that: In step (3), the particle size of the granulation is 2 to 5 mm.

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