Autotrophic denitrification filter material as well as preparation method and application thereof

Abstract

The invention provides an autotrophic denitrification filter material and a preparation method and application thereof, and belongs to the technical field of water treatment.The autotrophic denitrification filter material comprises the following raw materials: a main body material, an adhesive, a foaming agent and a slow-release agent, and the main body material is sulfur powder, thiosulfate and pyrite powder; the preparation method comprises the following steps: mixing the main materials to obtain a component A, mixing the slow-release agent to obtain a component B, mixing the component A and the component B, adding water, uniformly stirring, adding the adhesive and the foaming agent, heating, uniformly stirring, and granulating to obtain the filter material. The invention provides an autotrophic denitrification filter material as well as a preparation method and application thereof, and aims of obtaining a light filter material and quickly starting biofilm formation are fulfilled.

Description

Technical Field

[0001] The invention relates to the technical field of water treatment, and in particular to an autotrophic denitrification filter material and a preparation method and application thereof. Background Art

[0002] Total nitrogen is the total amount of various forms of inorganic and organic nitrogen in water, including NO 3- 、NO 2- and NH 4+ Inorganic nitrogen such as inorganic nitrogen and organic nitrogen such as proteins, amino acids and organic amines, calculated in milligrams of nitrogen per liter of water, is often used to indicate the degree of nutrient pollution in water bodies. Total nitrogen is one of the important indicators for measuring water quality. The current mature technical methods for removing total nitrogen mainly include: 1. Ion exchange method: The main exchangeable nitrates are Cl - and HCO 3- , but the effluent will lead to an increase in chlorine content, and a large amount of concentrated liquid will be produced during the resin adsorption regeneration, and the treatment and construction costs are very high; 2. Reverse osmosis: The amount of concentrated liquid is large, the treatment cost is high, and the life of the RO membrane is short; 3. Biochemical method (AAO): Through nitrification and denitrification, ammonia nitrogen is converted into nitrate nitrogen and then returned to the anoxic state for denitrification and reduction to nitrogen gas. The lack of carbon source is its main problem. To further reduce the total nitrogen, the cost of adding additional carbon sources will increase significantly and easily cause secondary pollution of COD exceeding the standard; 4. Autotrophic denitrification denitrification technology: Autotrophic denitrification denitrification technology mainly refers to the energy released in the redox reaction of inorganic matter as an electron donor and inorganic carbon compounds as a carbon source to denitrify. It has the advantages of high denitrification efficiency, low operating cost, and wide application range. Therefore, autotrophic denitrification denitrification technology has always been the focus of research by practitioners. As one of the key points of autotrophic denitrification denitrification technology, the filter material has a significant impact on the denitrification effect.

[0003] The patent with the announcement number CN116332329B, entitled "Sustained-release sulfur autotrophic denitrification biofilter material and its preparation method and application", discloses a preparation method of a sustained-release sulfur autotrophic denitrification biofilter material, comprising the following steps: preparing an adhesive: mixing redispersible rubber powder and wood cellulose to obtain an adhesive; preparing a core material ball: mixing clay, sodium thiosulfate and / or hydrosulfite, and sulfur, adding water, mixing and adding an adhesive, granulating and forming, and obtaining a core material ball; the clay is ball clay; preparing an autoclaved concrete premix: mixing raw materials cement, fly ash, lime, gypsum powder, and aluminum paste powder, adding water and mixing to obtain an autoclaved concrete premix; preparing a static curing material: mixing the core material balls in the autoclaved concrete premix, static curing, and obtaining a static curing material. The preparation method of the sustained-release sulfur autotrophic denitrification biofilter material provided by the above technical scheme, the sustained release effect of sulfur-containing substances in the prepared biofilter material, improves the denitrification and nitrogen removal effect of sewage. However, the preparation method in the above technical scheme is complicated, and the high density of the raw materials used determines that the prepared filter material is heavy. At the same time, the description of the above technical scheme records that 3-5 mm core material balls are mixed with autoclaved concrete premix in a weight ratio of 1-3:1 to obtain static curing material. It can be seen that although the filter material prepared in the above technical scheme has a sustained release effect, the filter material has a large mass and is distributed in the autoclaved concrete premix. The film-forming speed is slow. Summary of the invention

[0004] In view of this, the present invention provides an autotrophic denitrification filter material and a preparation method and application thereof, so as to achieve the purpose of obtaining a lightweight filter material and rapid biofilm formation and startup.

[0005] To achieve the above object, the present invention provides an autotrophic denitrification filter material, comprising the following raw materials: a main material, a binder, a foaming agent and a slow-release agent, wherein the main material is sulfur powder, thiosulfate and pyrite powder.

[0006] The reaction equation of the thiosulfate used in the present invention is: 0.844S2O3 2- +NO3 - +0.347CO2+0.086HCO3 - +0.0086NH4 + +0.434H2O→1.689SO4 2- +0.5N2+ 0.086C5H7O2N + 0.697H + The reaction equation of the sulphur powder used in the present invention is: NO3 - + 1.1S + 0.4CO2+ 0.76H2O + 0.08NH4 + →0.5N2+ 1.1SO4 2- + 1.28H ++0.08C5H7O2N The reaction equation of the pyrite powder used in the present invention is: 0.364FeS2+ 0.116CO2+ NO3 - + 0.82H2O + 0.023NH4 + →0.5N2+ 0.729SO4 2- +0.364Fe(OH)3+ 0.023C5H7O2N + 0.480H + Optionally, the thiosulfate is sodium thiosulfate, and the pyrite powder is marcasite powder; the weight ratio of the sulfur powder: sodium thiosulfate: marcasite powder is (75~85): (10~15): (5~10).

[0007] Optionally, the sustained-release agent is sodium carbonate, sodium bicarbonate and aluminum hydroxide.

[0008] Optionally, the weight ratio of sodium carbonate: sodium bicarbonate: aluminum hydroxide is (3-4): (5-8): (1-2).

[0009] Optionally, the weight ratio of the main material: sustained-release agent: adhesive: foaming agent is (80~110):(4~7):(10~12):(5~8).

[0010] Optionally, the adhesive is starch; and the foaming agent is ammonium bicarbonate.

[0011] In order to achieve the above-mentioned purpose, the present invention also provides a method for preparing an autotrophic denitrification filter material, comprising the following steps: taking a main material and mixing it to obtain component A, taking a slow-release agent and mixing it to obtain component B, mixing component A with component B, adding water and stirring evenly, adding a binder and a foaming agent, heating and stirring evenly, and granulating to obtain the filter material.

[0012] Optionally, the heating and stirring temperature is 40-50° C., and the stirring speed is 150-200 r / min.

[0013] Optionally, the particle size of the filter material is 4~8mm.

[0014] In order to achieve the above object, the present invention also provides an autotrophic denitrification filter material for use in the denitrification treatment of sewage.

[0015] The above technical solution of the present invention includes at least the following beneficial effects: The main material of the present invention uses thiosulfate, sulfur powder and pyrite as the main material after proportioning, wherein thiosulfate has high solubility, good mass transfer, low cost, and little effect on the pH of the system. Sulfur powder is chemically stable as elemental sulfur, and is used as an electron donor and filter material for microbial growth, which is cheap and easy to handle and transport. The Fe and S elements contained in pyrite can provide electrons for microorganisms, and iron-sulfur compounds are insoluble in water and are usually used as biological carriers. Compared with elemental sulfur, it consumes less alkalinity of inorganic carbon sources, produces much less sulfate, and generally does not need to adjust the alkalinity. At the same time, it can also remove phosphates.

[0016] The present invention uses a mixture of sodium carbonate, sodium bicarbonate and aluminum hydroxide to make the filter material work for a long time, and uses starch and ammonium bicarbonate as auxiliary materials, so that microorganisms can reproduce quickly and form biofilms quickly, and has a significant denitrification effect on sewage with different total nitrogen contents. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a physical picture of the filter material prepared in Example 1 of the present invention; Figure 2 This is a data diagram of denitrification of wastewater with low total nitrogen concentration when the filter material is actually applied in Example 4 of the present invention; Figure 3 This is a data diagram of denitrification of sewage with a total nitrogen concentration when the filter material is actually applied in Example 4 of the present invention; Figure 4 This is a data chart of denitrification of total nitrogen high-concentration wastewater when the filter material is actually applied in Example 4 of the present invention. DETAILED DESCRIPTION

[0018] To make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the following will be combined with the appended drawings of the embodiments of the present invention. Figures 1 to 4 , the technical scheme of the embodiment of the present invention is clearly and completely described. Obviously, the described embodiment is a part of the embodiment of the present invention, not all of the embodiments. Based on the described embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present invention.

[0019] Example 1 Accurately weigh 200g of sulfur powder, 39g of sodium thiosulfate powder, and 26g of white iron ore powder and mix them evenly to obtain component A. Weigh 4.8g of sodium carbonate, 9.6g of sodium bicarbonate, and 2.6g of aluminum hydroxide, mix them evenly to obtain component B, mix A and B evenly, add purified water and stir until paste-like, add 32g of starch and 16g of ammonium bicarbonate, transfer to a heating kettle, heat and stir at 40°C and 150r / min until tiny bubbles are visible on the surface of the material, feed the material to a granulator, extrude and cut into 4~8mm granular fillers, and cool at room temperature to obtain the prepared filter material. The actual filter material is shown in the figure below: Figure 1 .

[0020] Example 2 Accurately weigh 200g of sulfur powder, 26g of sodium thiosulfate powder, and 13g of white iron ore powder and mix them evenly to obtain component A. Weigh 4g of sodium carbonate, 8g of sodium bicarbonate, and 2g of aluminum hydroxide, mix them evenly to obtain component B, mix A and B evenly, add purified water and stir until paste-like, add 24g of starch and 16g of ammonium bicarbonate, transfer to a heating kettle, heat and stir at 45°C and 200r / min until tiny bubbles are visible on the surface of the material, feed the material to a granulator, extrude and cut into 4~8mm granular fillers, and cool at room temperature to obtain the prepared filter material.

[0021] Example 3 Accurately weigh 200g of sulfur powder, 39g of sodium thiosulfate powder, and 26g of white iron ore powder and mix them evenly to obtain component A. Weigh 4.8g of sodium carbonate, 9.6g of sodium bicarbonate, and 2.6g of aluminum hydroxide, mix them evenly to obtain component B, mix A and B, add purified water and stir until paste-like, add 32g of starch and 16g of ammonium bicarbonate, transfer to a heating kettle, heat and stir at 50°C and 200r / min until tiny bubbles are visible on the surface of the material, feed the material to a granulator, extrude and cut into 4-8mm granular fillers, and cool at room temperature to obtain the prepared filter material.

[0022] Example 4 Two 2.23*2.5*6 meter denitrification deep bed filters were built at a sewage station in Chongqing, and large-scale application experiments were carried out. The filter material prepared in Example 1 was used as filler, and the filler of a single reactor was 12m³. The denitrification effects of low-concentration total nitrogen sewage, medium-concentration total nitrogen sewage and high-concentration total nitrogen sewage were actually tested. The alkalinity of the inlet water was basically maintained between 300-500mg / L (calculated as calcium carbonate), the inlet SS ≤20mg / L, and the pH was between 7.2-8.2. Among them, the inlet volume of low-concentration total nitrogen sewage was controlled between 20-22m³ / h; the inlet volume of medium-concentration total nitrogen sewage was controlled between 10-13m³ / h; and the inlet volume of high-concentration total nitrogen sewage was controlled between 9-12m³ / h. The inlet total nitrogen content, effluent total nitrogen content and denitrification load were counted separately to obtain data. Some of the data are as follows Figure 2 , 3 、4.

[0023] Combination Figure 2 , 3 4 It can be seen that the autotrophic denitrification filter material provided by the present invention has a denitrification load maintained at 1-1.3 [kg N / (m³·d)]. According to the adjustment of the total nitrogen concentration in the influent, it can be seen that it has excellent treatment effects on sewage with low, medium and high total nitrogen content, has a wide range of adaptability, and is easy to promote in actual engineering applications.

[0024] In the present invention, unless otherwise clearly stipulated and limited, for example, it can be a fixed connection, a detachable connection, or an integrated one; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. Unless otherwise clearly defined, for ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0025] The above are preferred embodiments of the present invention. It should be pointed out that, for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. An autotrophic denitrification filter material, characterized in that: The invention comprises the following raw materials: a main material, an adhesive, a foaming agent and a slow-release agent, wherein the main material is sulfur powder, thiosulfate and pyrite powder.

2. The autotrophic denitrification filter material according to claim 1, characterized in that The thiosulfate is sodium thiosulfate, and the pyrite powder is marcasite powder; the weight ratio of the sulfur powder: sodium thiosulfate: marcasite powder is (75-85): (10-15): (5-10).

3. The autotrophic denitrification filter material according to claim 1, characterized in that The sustained-release agents are sodium carbonate, sodium bicarbonate and aluminum hydroxide.

4. The autotrophic denitrification filter material according to claim 3, characterized in that: The weight ratio of the sodium carbonate:sodium bicarbonate:aluminum hydroxide is (3-4):(5-8):(1-2).

5. The autotrophic denitrification filter material according to claim 1, characterized in that: The weight ratio of the main material: sustained-release agent: adhesive: foaming agent is (80-110): (4-7): (10-12): (5-8).

6. The autotrophic denitrification filter material according to claim 1, characterized in that: The adhesive is starch; the foaming agent is ammonium bicarbonate.

7. A method for preparing an autotrophic denitrification filter material according to any one of claims 1 to 6, characterized in that: The following steps are involved: The main material is mixed to obtain component A, and the sustained-release agent is mixed to obtain component B. Component A and component B are mixed, water is added and stirred evenly, a binder and a foaming agent are added, heated and stirred evenly, and granulated to obtain a filter material.

8. The method for preparing the autotrophic denitrification filter material according to claim 7, characterized in that: The heating and stirring temperature is 40-50° C., and the stirring speed is 150-200 r / min.

9. The method for preparing the autotrophic denitrification filter material according to claim 7, characterized in that: The particle size of the filter material is 4-8 mm.

10. An autotrophic denitrification filter material as claimed in any one of claims 1 to 6, used for denitrification treatment of sewage.

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