A coated sulfur-carrying mineral-based biofilter material for simultaneous denitrification and dephosphorization of wastewater, preparation method and application thereof

Abstract

The invention provides a coated sulfur-carrying mineral-based biofilter material for simultaneous nitrogen and phosphorus removal in wastewater, a preparation method and an application thereof, and belongs to the field of wastewater treatment, comprising: selecting pyrite ore with a preset particle size as a core material according to the water quality characteristics of the treated wastewater; stirring and mixing the powder materials in the following mass parts to obtain a mixed powder material: 3 parts to 10 parts of sulfur, 20 parts to 50 parts of sulfur concentrate, 15 parts to 20 parts of cement, 1 part to 3 parts of gypsum, and 1 part to 1 part of lime. 3 parts, diatomaceous earth 1 part-3 parts, fly ash 5 parts-50 parts; wherein, the proportion of particle size of each powder is 200 mesh is 50%; 10 parts-30 parts by mass of pyrite ore are added as core material into the disc pelletizer to make core, and then the mixed powder is used as coating material, the mixed powder is added to the disc pelletizer gradually and water is sprayed, spread at 20℃-25℃, spray wet and cure for 28-30 days to obtain a coated sulfur-loaded mineral-based biofilter material.

Description

Technical Field

[0001] This invention belongs to the field of wastewater treatment technology, specifically relating to a coated sulfur-loaded mineral-based biological filter media for simultaneous nitrogen and phosphorus removal from wastewater, its preparation method, and its application. Background Technology

[0002] The large-scale discharge of nitrogen- and phosphorus-containing wastewater is a major cause of eutrophication in water bodies. Although anaerobic / anoxic / aerobic (A...) treatment methods exist... 2 Traditional processes such as nitrogen oxides (NOx) can effectively reduce nitrogen and phosphorus concentrations in water, and the effluent quality meets the pollutant discharge requirements of urban wastewater treatment plants. Currently, the sulfur sources for sulfur autotrophic denitrification technology are mainly sulfides, elemental sulfur, and pyrite. Elemental sulfur easily causes a continuous increase in sulfate concentration and a decrease in pH in the effluent, while sulfides have high requirements for reactor structure and process operation. Pyrite is abundant in nature and its price is much lower than elemental sulfur, making it a superior electron donor in sulfur autotrophic denitrification. Using pyrite as the sulfur source for denitrification can not only achieve nitrogen removal, but also allow the ferrous or ferric ions produced by denitrification to adsorb and precipitate with phosphate ions, thereby achieving phosphorus removal.

[0003] Current methods for preparing biological filter media mainly employ high-temperature calcination granulation, which is not suitable for preparing biological filter media for sulfur autotrophic denitrification.

[0004] Regardless of whether sulfur, pyrite ore particles, or sulfur concentrate is used as the sulfur source, significant sulfur loss occurs during high-temperature preparation. Furthermore, the binders, pore-forming agents, and other additives commonly used in high-temperature roasting granulation methods often have some water solubility, making them unsuitable for non-fired preparation of biological filter media. Otherwise, the biological filter media may experience a decrease in strength or even disintegration and loss during long-term use, affecting denitrification efficiency and the normal operation of the process. Additionally, existing sulfur autotrophic denitrification technologies lead to a decrease in system alkalinity during denitrification, causing pH instability. A certain amount of alkaline substances needs to be added to maintain system pH balance and ensure that microbial growth and reproduction occur within a suitable acid-base range. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a coated sulfur-loaded mineral-based biological filter material for simultaneous denitrification and phosphorus removal in wastewater, its preparation method and its application, so as to solve the problems mentioned in the background art.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0007] On the one hand, a method for preparing coated sulfur-loaded mineral-based biological filter media for simultaneous nitrogen and phosphorus removal from wastewater is provided, the method comprising:

[0008] S101. Based on the characteristics of the wastewater being treated, select pyrite ore of a preset particle size as the core material.

[0009] S102. Mix the powders evenly according to the following mass parts to obtain a mixed powder: 3-10 parts sulfur, 20-50 parts sulfur concentrate, 15-20 parts cement, 1-3 parts gypsum, 1-3 parts lime, 1-3 parts diatomaceous earth, and 5-50 parts fly ash; wherein, the proportion of particles with a particle size of -200 mesh in each powder is not less than 50%.

[0010] S103. Add 10-30 parts by weight of pyrite ore as core material to the disc pelletizer to form cores, add water to moisten the surface of the pyrite ore core material, and then use the mixed powder as coating material to add the mixed powder to the disc pelletizer in 2-4 batches and spray water, wherein the total amount of water added is 20%-30% of the mixed powder.

[0011] S104. After the mixed powder is spherical with pyrite ore as the core and the spherical size reaches the preset size, it is taken out and spread at 20℃-25℃, sprayed with water and naturally cured and aged for 28-30 days to obtain the coated sulfur-loaded mineral-based biological filter material.

[0012] Preferably, the method includes:

[0013] S201. Based on the characteristics of the wastewater being treated, select pyrite ore of a preset particle size as the core material.

[0014] S202. Mix the powders according to the following mass proportions to obtain a mixed powder: 20-50 parts sulfur concentrate, 15-20 parts cement, 1-3 parts gypsum, 1-3 parts lime, 1-3 parts diatomaceous earth, and 5-50 parts fly ash; wherein, the proportion of particles with a particle size of -200 mesh in each powder is not less than 50%.

[0015] S203. Divide the mixed powder into 3-4 batches according to mass, take 1 batch and add 3-10 parts of sulfur, and stir and mix them evenly.

[0016] S204. Add 10-30 parts by weight of pyrite ore as core material to the disc pelletizer. Moisten the surface of the pyrite ore core material with water. Then, use mixed powder as coating material. Add the mixed powder batch by batch to the disc pelletizer and spray water. The total water content is 20%-30% of the mixed powder. Among them, the batch of mixed powder mixed with sulfur is added last as the outermost coating material of the biological filter media.

[0017] S205. After the mixed powder is spherical with pyrite ore as the core and the spherical size reaches the preset size, it is taken out and spread at 20℃-25℃, sprayed with water and naturally cured and aged for 28-30 days to obtain coated sulfur-loaded mineral-based biological filter media.

[0018] Preferably, the preset particle size is 1mm-9mm.

[0019] Preferably, the powders are stirred and mixed for at least 15 minutes using a stirring machine until they are uniformly mixed.

[0020] Preferably, the cement is ordinary Portland cement.

[0021] Preferably, the gypsum is dihydrate gypsum.

[0022] Preferably, the selected pyrite ore has a sulfur content of 18% or higher.

[0023] On the other hand, a coated sulfur-loaded mineral-based biological filter media for simultaneous nitrogen and phosphorus removal from wastewater is provided. The coated sulfur-loaded mineral-based biological filter media is prepared using any of the methods described above, and comprises:

[0024] Pyrite ore core material with a mass fraction of 10-30 parts;

[0025] The coating material consists of 3-10 parts sulfur, 20-50 parts sulfur concentrate, 15-20 parts cement, 1-3 parts gypsum, 1-3 parts lime, 1-3 parts diatomaceous earth, and 5-50 parts fly ash.

[0026] Preferably, the coated sulfur-loaded mineral-based biofilter material comprises:

[0027] Pyrite ore core material with a mass fraction of 15-20 parts;

[0028] The coating material consists of 4-8 parts sulfur, 30-40 parts sulfur concentrate, 17-20 parts cement, 1-2.5 parts gypsum, 1-2.5 parts lime, 1-2.5 parts diatomaceous earth, and 25-35 parts fly ash.

[0029] On another front, an application of coated sulfur-loaded mineral-based biological filter media for simultaneous nitrogen and phosphorus removal from wastewater is provided. The coated sulfur-loaded mineral-based biological filter media is applied in an anaerobic fluidized bed, and the amount added is 1 / 3 to 2 / 3 of the total volume of the anaerobic fluidized bed.

[0030] Compared with the prior art, the present invention has at least the following beneficial effects:

[0031] (1) The method provided in the embodiments of the present invention uses pyrite ore as core material and a mixed powder containing sulfur and sulfur concentrate as coating material. It adopts a non-fired process to produce coated sulfur-loaded mineral-based biological filter media. The filter media balls have a large specific surface area, abundant micropores, easy biofilm formation, large biomass, good autotrophic denitrification and nitrogen removal effect, and high phosphorus removal efficiency.

[0032] (2) The method provided in the embodiments of the present invention can select pyrite ore of different sulfur grades as the core and sulfur concentrate of different grades as the coating material according to the nitrogen and phosphorus load of wastewater and the service cycle of filter media. Sulfur powder is added in the last batch of powder and coated on the outermost layer of filter media. The sulfur source in the filter media ball is sulfur powder, sulfur concentrate and pyrite particles from the outside to the inside. It has fast start-up, good mass transfer and high utilization rate.

[0033] (3) The alkaline substance lime in the biological filter material prepared in the embodiments of the present invention can slowly release alkalinity, maintain the appropriate pH range for the growth and reproduction of denitrifying bacteria, and effectively avoid the pH decrease caused by the consumption of alkalinity in the sulfur autotrophic denitrification process.

[0034] (4) The bulk density of the biological filter media prepared in the embodiments of the present invention is 1.0 t / m³. 3 -1.5t / m 3 With dimensions ranging from 6mm to 20mm, and both bulk density and size can be adjusted as needed, this material is suitable for various biofilm reactors. It can effectively overcome the defects of fluidized beds, such as difficulty in control and easy material loss, and also avoid the problems of complex, time-consuming, and energy-intensive backwashing systems in biofilters.

[0035] (5) The biological filter media prepared in this embodiment of the invention does not contain any substances harmful to the human body and the environment, does not produce secondary pollution, has high mechanical strength, is resistant to washing and wear, has good biological and chemical stability, a long service life, stable effect, and low cost. Moreover, the used biological filter media can be crushed and processed using mineral processing methods to recover the pyrite ore, thereby realizing the reuse of iron resources. Attached Figure Description

[0036] The accompanying drawings, which are incorporated herein and form part of the specification, illustrate embodiments of the present disclosure and, together with the specification, further serve to explain the principles of the present disclosure and enable those skilled in the art to implement and use the present disclosure.

[0037] Figure 1 This is a schematic diagram of the preparation method of a coated sulfur-loaded mineral-based biological filter material for simultaneous nitrogen and phosphorus removal from wastewater according to the present invention.

[0038] Figure 2 This is a schematic diagram of the preparation method of another type of coated sulfur-loaded mineral-based biological filter media for simultaneous denitrification and phosphorus removal in wastewater according to the present invention. Detailed Implementation

[0039] The following detailed description, in conjunction with the accompanying drawings and specific embodiments, provides an illustrated method for the preparation of a coated sulfur-loaded mineral-based biological filter media for simultaneous nitrogen and phosphorus removal from wastewater, along with its application. It should be noted that the embodiments described below are preferred and optimal examples to provide a more comprehensive overview. Those skilled in the art may employ alternative methods to implement certain known technologies. Furthermore, the accompanying drawings are provided solely for the purpose of describing the embodiments in greater detail and are not intended to limit the scope of the invention.

[0040] It should be noted that the use of terms such as "an embodiment," "an embodiment," "an exemplary embodiment," and "some embodiments" in the specification indicates that the described embodiment may include a specific feature, structure, or characteristic, but not every embodiment necessarily includes that specific feature, structure, or characteristic. Furthermore, when a specific feature, structure, or characteristic is described in connection with an embodiment, implementing such a feature, structure, or characteristic in conjunction with other embodiments (whether explicitly described or not) should be within the knowledge of those skilled in the art.

[0041] Generally, terms can be understood at least partly from their use in context. For example, depending at least partly on the context, the term "one or more" as used herein can be used to describe any feature, structure, or characteristic in a singular sense, or a combination of features, structures, or characteristics in a plural sense. Additionally, the term "based on" can be understood not necessarily to convey an exclusive set of factors, but rather, alternatively, depending at least partly on the context, to allow for the presence of other factors that are not necessarily explicitly described.

[0042] As used herein, the term "nominal / nominally" refers to the expected or target value of a characteristic or parameter for the operation of a component or process, set during the design phase of the production or manufacturing process, and the range of values ​​higher and / or lower than the expected value. The range of values ​​may be due to slight variations in the manufacturing process or tolerances. As used herein, the term "about" indicates the value of a given quantity that can vary based on a specific technology node associated with the subject semiconductor device. Based on a specific technology node, the term "about" can indicate the value of a given quantity that varies, for example, within 5 to 15 parts of the value (e.g., ±5, ±10, or ±15 parts of the value).

[0043] like Figure 1 As shown, in one aspect, embodiments of the present invention provide a method for preparing coated sulfur-loaded mineral-based biological filter media for simultaneous nitrogen and phosphorus removal from wastewater, the method comprising:

[0044] S101. Based on the characteristics of the wastewater being treated, select pyrite ore of a preset particle size as the core material.

[0045] S102. Mix the powders evenly according to the following mass parts to obtain a mixed powder: 3-10 parts sulfur, 20-50 parts sulfur concentrate, 15-20 parts cement, 1-3 parts gypsum, 1-3 parts lime, 1-3 parts diatomaceous earth, and 5-50 parts fly ash as a coating material; wherein, the proportion of particles with a particle size of -200 mesh in each powder is 50%.

[0046] S103. Add 10-30 parts by weight of pyrite ore as core material to the disc pelletizer to form cores, add water to moisten the surface of the pyrite ore core material, and then use mixed powder as coating material. Add the mixed powder to the disc pelletizer in 2-4 batches and spray water. The total amount of water added is 20-30 parts of the mixed powder.

[0047] S104. After the mixed powder is spherical with pyrite ore as the core and the spherical size reaches the preset size, it is taken out and spread at 20℃-25℃, sprayed with water and naturally cured and aged for 28-30 days to obtain coated sulfur-loaded mineral-based biological filter media.

[0048] Preferably, embodiments of the present invention provide a method for preparing coated sulfur-loaded mineral-based biological filter media for simultaneous nitrogen and phosphorus removal from wastewater. Please refer to [link to relevant documentation]. Figure 2 , methods include:

[0049] S201. Based on the characteristics of the wastewater being treated, select pyrite ore of a preset particle size as the core material.

[0050] S202. Mix the powders according to the following mass proportions to obtain a mixed powder: 20-50 parts sulfur concentrate, 15-20 parts cement, 1-3 parts gypsum, 1-3 parts lime, 1-3 parts diatomaceous earth, and 5-50 parts fly ash; wherein, the proportion of particles with a particle size of -200 mesh in each powder is not less than 50%.

[0051] S203. Divide the mixed powder into 3-4 batches according to mass, take 1 batch and add 3-10 parts of sulfur, and stir and mix them evenly.

[0052] S204. Pyrite ore in a mass ratio of 10-30 parts is added to a disc pelletizer as core material. Water is added to moisten the surface of the pyrite core material. Then, the mixed powder is added batch by batch to the disc pelletizer as a coating material, with water sprayed on top. The total water content is 20%-30% of the mixed powder. One batch of the mixed powder containing sulfur is added last, serving as the outermost coating material for the biological filter media.

[0053] S205. After the mixed powder is spherical with pyrite ore as the core and the spherical size reaches the preset size, it is taken out and spread at 20℃-25℃, sprayed with water and naturally cured and aged for 28-30 days to obtain the coated sulfur-loaded mineral-based biological filter material.

[0054] The preparation method provided by the embodiments of the present invention will be further explained and described below through optional examples.

[0055] Preferably, in S101 or S201, the preset particle size of the selected pyrite ore is 1mm-9mm.

[0056] Based on the characteristics of the wastewater being treated, pyrite ore with different sulfur grades (containing more than 18% sulfur) is selected. The ore is then crushed into particles of 1-3mm, 3-6mm, 6-9mm, or even larger, according to the required size of the biological filter media. Coarse particles can be used as the core for large-sized biological filter media, while fine particles can be used for small-sized biological filter media. The particle size of the pyrite ore selected in this embodiment of the invention is not limited to these specifications.

[0057] Preferably, in S102 or S202, the powders are stirred and mixed for more than 15 minutes by a stirring machine until they are uniformly mixed.

[0058] Preferably, the cement is ordinary Portland cement.

[0059] Preferably, the gypsum is dihydrate gypsum.

[0060] Preferably, in S101 or S201, the selected pyrite ore has a sulfur content of 18% or higher.

[0061] On the other hand, a coated sulfur-loaded mineral-based biological filter media for simultaneous nitrogen and phosphorus removal from wastewater is provided. The coated sulfur-loaded mineral-based biological filter media is prepared using any of the methods described above, and includes:

[0062] Pyrite ore core material with a mass fraction of 10-30 parts;

[0063] The coating material consists of 3-10 parts sulfur, 20-50 parts sulfur concentrate, 15-20 parts cement, 1-3 parts gypsum, 1-3 parts lime, 1-3 parts diatomaceous earth, and 5-50 parts fly ash.

[0064] Furthermore, the coated sulfur-loaded mineral-based biofilter media includes: 10, 12, 13, 14, 15, 16, 18, 19, 20, 21, 23, 24, 25, 26, 27, 28, 29, and 30 parts of pyrite core; 3, 4, 5, 6, 7, 8, 9, and 10 parts of sulfur; 20, 21, 23, 24, 25, 26, 27, 28, 29, 30, 33, 34, 36, 37, 39, 40, 41, 42, 43, 45, 47, 48, 49, and 50 parts of cement; and 15, 16, 18, 19, and 20 parts of cement. 1 part gypsum, 1.2 parts 1.9 parts 2 parts 2.5 parts 3 parts. 1 part lime, 1.2 parts 1.9 parts 2 parts 2.5 parts 3 parts. 1 part diatomaceous earth, 1.2 parts 1.9 parts 2 parts 2.5 parts 3 parts. 5 parts fly ash, 6 parts 7 parts 8 parts 10 parts 12 parts 13 parts 14 parts 15 parts 16 parts 18 parts 19 parts 20 parts 21 parts 23 parts 24 parts 25 parts 26 parts 27 parts 28 parts 29 parts 30 parts 33 parts 34 parts 36 parts 37 parts 39 parts 40 parts 41 parts 42 parts 43 parts 45 parts 47 parts 48 parts 49 parts 50 parts.

[0065] Preferably, the coated sulfur-loaded mineral-based biofilter media includes:

[0066] Pyrite ore core material with a mass fraction of 15-20 parts;

[0067] The coating material consists of 4-8 parts sulfur, 30-40 parts sulfur concentrate, 17-20 parts cement, 1-2.5 parts gypsum, 1-2.5 parts lime, 1-2.5 parts diatomaceous earth, and 25-35 parts fly ash.

[0068] On another front, an application of coated sulfur-loaded mineral-based biological filter media for simultaneous nitrogen and phosphorus removal from wastewater is provided. The coated sulfur-loaded mineral-based biological filter media is applied in an anaerobic fluidized bed, and the addition amount is 1 / 3 to 2 / 3 of the effective volume of the anaerobic fluidized bed.

[0069] The preparation method provided by the embodiments of the present invention is described below through specific examples.

[0070] Example 1

[0071] The present invention provides a method for preparing coated sulfur-loaded mineral-based biological filter media for simultaneous nitrogen and phosphorus removal from wastewater, as detailed below:

[0072] (1) Large pyrite blocks with a sulfur grade of 24% are crushed to less than 10mm using a jaw crusher and screened to obtain 3-6mm particle size as core material for preparing biological filter media.

[0073] (2) Weigh and mix other dry powders according to their mass parts to obtain mixed powder: 20 parts of ordinary silicate cement, 2 parts of dihydrate gypsum, 3 parts of lime, 3 parts of diatomite, 12 parts of fly ash, 5 parts of sulfur, and 35 parts of mineral beneficiation sulfur concentrate with a sulfur grade of 38%. Add each powder to the mixer and mix for 30 minutes until uniform. Take it out and divide it into 3 equal parts according to mass.

[0074] (3) Weigh 15 parts of pyrite ore particles of 3-6mm and pour them into a disc pelletizer as pelletizing material. Spray water to wet the surface of the particles and add the mixed powder one by one. At the same time, spray water to make coated sulfur-loaded mineral-based biological filter media. The total amount of water added is 30% of the amount of mixed powder. Prepare spherical coated sulfur-loaded mineral-based biological filter media with a diameter of 9mm.

[0075] (4) The prepared coated sulfur-loaded mineral-based biological filter material was sprayed with water at room temperature for natural curing and aging for 28 days.

[0076] (5) Add this biological filter media to the anaerobic fluidized bed at a volume of 1 / 3 of the total volume. This serves as a highly efficient reaction carrier for anaerobic microorganisms, treating NO3-N (20 mg / L) and PO4. 3- Wastewater concentration: 12.25 mg / L.

[0077] Example 2

[0078] The present invention provides a method for preparing coated sulfur-loaded mineral-based biological filter media for simultaneous nitrogen and phosphorus removal from wastewater, as detailed below:

[0079] (1) Large pyrite blocks with a sulfur grade of 24% are crushed to less than 10mm using a jaw crusher and screened to obtain 3-6mm particle size as core material for preparing biological filter media.

[0080] (2) Weigh and mix other dry powders according to their mass parts to obtain mixed powder: 15 parts of ordinary silicate cement, 2 parts of dihydrate gypsum, 3 parts of lime, 3 parts of diatomite, 12 parts of fly ash, 5 parts of sulfur, and 35 parts of mineral beneficiation sulfur concentrate with a sulfur grade of 38%. Add each powder to the mixer and mix for 30 minutes until uniform. Take it out and divide it into 3 equal parts according to mass.

[0081] (3) Weigh 25 parts of pyrite ore particles of 3-6mm and pour them into a disc pelletizer as pelletizing material. Spray water to wet the surface of the particles and add the mixed powder one by one. At the same time, spray water to make coated sulfur-loaded mineral-based biological filter media. The total amount of water added is 20% of the amount of mixed powder. Prepare spherical coated sulfur-loaded mineral-based biological filter media with a diameter of 9mm.

[0082] (4) The prepared coated sulfur-loaded mineral-based biological filter material was sprayed with water at room temperature for natural curing and aging for 28 days.

[0083] (5) Add this biological filter media to the anaerobic fluidized bed at a volume of 1 / 3 of the total volume. This serves as a highly efficient reaction carrier for anaerobic microorganisms, treating NO3-N (20 mg / L) and PO4. 3- Wastewater concentration: 12.25 mg / L.

[0084] Example 3

[0085] In this embodiment, the sulfur concentrate is evenly distributed, with sulfur only in the outermost layer. This results in a higher concentration of elemental sulfur in the outermost layer, making initiation easier and improving the initial treatment effect. The specific preparation method is as follows:

[0086] (1) Large pyrite blocks with a sulfur grade of 24% are crushed to less than 10mm using a jaw crusher and screened to obtain 6-10mm particle size as core material for preparing biological filter media.

[0087] (2) Weigh and mix other dry powders according to their mass parts to obtain mixed powder: 19 parts of ordinary silicate cement, 3 parts of dihydrate gypsum, 3 parts of lime, 2 parts of diatomite, 11 parts of fly ash, and 45 parts of mineral beneficiation sulfur concentrate with a sulfur grade of 38 parts. Add each powder to the mixer and mix for 30 minutes until uniform. Take it out and divide it into 4 equal parts by mass.

[0088] (3) Take out one portion of the mixed powder, add 3.5 parts of sulfur powder according to the total mass ratio, and mix well;

[0089] (4) Weigh 13.5 parts of 6-10mm pyrite ore particles and pour them into a disc pelletizer as pelletizing material. Spray water to wet the surface of the particles and add the mixed powders taken out in step (2) one by one. Finally, add the powder mixed with sulfur powder. Spray water to make pellets at the same time. The total amount of water added is 30% of the amount of mixed powder. Prepare spherical coated sulfur-loaded mineral-based biological filter media with a diameter of 16mm. The sulfur source of this spherical coated sulfur-loaded mineral-based biological filter media is mainly the sulfur and sulfur concentrate of the outermost coating, the sulfur concentrate of the outermost layer, and the pyrite particles of the core.

[0090] (5) The prepared filter material is sprayed with water at room temperature for natural curing and aging, and the curing time is 28 days;

[0091] (6) Add the spherical coated sulfur-loaded mineral-based biological filter media to the anaerobic non-rinsing fixed bed. The amount added is 1 / 2 of the effective volume of the fixed bed. It serves as a highly efficient reaction carrier for anaerobic microorganisms to treat aquaculture wastewater.

[0092] Example 4

[0093] In this embodiment, the sulfur concentrate is evenly distributed, with sulfur only in the outermost layer. This results in a higher concentration of elemental sulfur in the outermost layer, making initiation easier and improving the initial treatment effect. The specific preparation method is as follows:

[0094] (1) Large pyrite blocks with a sulfur grade of 24% are crushed to less than 10mm using a jaw crusher and screened to obtain 6-10mm particle size as core material for preparing biological filter media.

[0095] (2) Weigh and mix other dry powders according to their mass parts to obtain mixed powder: 20 parts of ordinary silicate cement, 2.5 parts of dihydrate gypsum, 2 parts of lime, 2 parts of diatomite, 11 parts of fly ash, and 45 parts of mineral beneficiation sulfur concentrate with a sulfur grade of 38 parts. Add each powder to the mixer and mix for 30 minutes until uniform. Take it out and divide it into 4 equal parts by mass.

[0096] (3) Take out one portion of the mixed powder, add four parts of sulfur powder of the total mass ratio to it, and mix well;

[0097] (4) Weigh 13.5 parts of 6-10mm pyrite ore particles and pour them into a disc pelletizer as pelletizing material. Spray water to wet the surface of the particles and add the mixed powders taken out in step (2) one by one. Finally, add the powder mixed with sulfur powder. Spray water to make pellets at the same time. The total amount of water added is 30% of the amount of mixed powder. Prepare spherical coated sulfur-loaded mineral-based biological filter media with a diameter of 16mm. The sulfur source of this spherical coated sulfur-loaded mineral-based biological filter media is mainly the sulfur and sulfur concentrate of the outermost coating, the sulfur concentrate of the outermost layer, and the pyrite particles of the core.

[0098] (5) The prepared filter material is sprayed with water at room temperature for natural curing and aging, and the curing time is 28 days;

[0099] (6) Add the spherical coated sulfur-loaded mineral-based biological filter media to the anaerobic non-rinsing fixed bed. The amount added is 1 / 2 of the effective volume of the fixed bed. It serves as a highly efficient reaction carrier for anaerobic microorganisms to treat aquaculture wastewater.

[0100] Comparative Example 1

[0101] (1) Large pyrite blocks with a sulfur grade of 24% are crushed to less than 10mm using a jaw crusher and screened to obtain 6-10mm particle size as core material for preparing biological filter media.

[0102] (2) Weigh and mix other dry powders according to their mass parts to obtain mixed powders: 10 parts of ordinary silicate cement, 1 part of sulfur powder, 5 parts of gypsum dihydrate, 5 parts of lime, 5 parts of diatomite, 11 parts of fly ash, and 45 parts of mineral beneficiation sulfur concentrate with a sulfur grade of 38 parts. Add each powder to a mixer and mix for 30 minutes until uniform. Calcine at high temperature for 60 minutes.

[0103] (3) Simultaneously spray water to form balls, with the total water added being 30% of the mixed powder, to prepare spherical coated sulfur-loaded mineral-based biological filter media with a diameter of 16 mm;

[0104] (5) The prepared filter material is sprayed with water at room temperature for natural curing and aging for 28 days.

[0105] Comparative Example 2

[0106] (1) Large pyrite blocks with a sulfur grade of 24% are crushed to less than 10mm using a jaw crusher and screened to obtain 6-10mm particle size as core material for preparing biological filter media.

[0107] (2) Weigh and mix other dry powders according to their mass parts to obtain mixed powders: 19 parts of ordinary silicate cement, 10 parts of dihydrate gypsum, 5 parts of lime, 2 parts of diatomite, 11 parts of fly ash, and 45 parts of mineral beneficiation sulfur concentrate with a sulfur grade of 38 parts. Add each powder to the mixer and mix for 30 minutes until uniform.

[0108] Add all the powders to the mixer and mix for 30 minutes until uniform. Then calcine at high temperature for 40 minutes.

[0109] (3) Simultaneously spray water to form balls, with the total water added being 20% ​​of the mixed powder amount, to prepare spherical coated sulfur-loaded mineral-based biological filter media with a diameter of 16 mm;

[0110] (5) The prepared filter material is sprayed with water at room temperature for natural curing and aging for 28 days.

[0111] The size, bulk density, porosity, cylinder compressive strength, and denitrification and phosphorus removal effects of the biological filter media prepared in Examples 1, 2, 3, 4, and Comparative Examples 1 and 2 were tested, and the results are shown in the table.

[0112]

[0113] As can be seen from the above embodiments, the denitrification and phosphorus removal effects of the biological filter media prepared by the methods provided in Embodiments 1-4 of the present invention are far superior to those of the biological filter media prepared by the methods provided in Comparative Examples 1-2.

[0114] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a coated sulfur-bearing mineral-based biofilter material for simultaneous denitrification and dephosphorization of wastewater, characterized in that: The method comprises: S101. According to the water quality characteristics of the treated wastewater, pyrite ore of a preset particle size is selected as a core material; S102, mixing the powders in the following parts by weight to obtain a mixed powder: 3-10 parts of sulfur, 20-50 parts of sulfur concentrate, 15-20 parts of cement, 1-3 parts of gypsum, 1-3 parts of lime, 1-3 parts of diatomaceous earth, and 5-50 parts of fly ash; wherein the proportion of the powders with a particle size of -200 mesh in each powder is not less than 50%; S103, adding 10-30 parts by mass of pyrite ore as core material into a disc pelletizing machine as core, adding water to wet the surface of the pyrite ore core material, and then using the mixed powder as a coating material, adding the mixed powder into the disc pelletizing machine in 2-4 batches and spraying water, wherein the total amount of water added is 20%-30% of the mixed powder; S104, the powder to be mixed is formed into balls with pyrite ore as the core and the balls are taken out after the size reaches a preset size, spread at 20° C.-25° C., sprayed with water, and naturally cured and aged for 28 days-30 days to obtain the coated sulfur-carrying mineral-based biofilter material.

2. A method for preparing a coated sulfur-bearing mineral-based biofilter for simultaneous denitrification and dephosphorization of wastewater, characterized in that: The method comprises: S201. According to the water quality characteristics of the treated wastewater, pyrite ore of a preset particle size is selected as a core material; S202, mixing the powders in the following parts by weight to obtain a mixed powder: 20-50 parts of sulfur concentrate, 15-20 parts of cement, 1-3 parts of gypsum, 1-3 parts of lime, 1-3 parts of diatomaceous earth, and 5-50 parts of fly ash; wherein the proportion of the powders with a particle size of -200 mesh in each powder is not less than 50%; S203, dividing the mixed powder into 3-4 batches by mass, adding 3-10 parts of sulfur to one of the batches, and stirring and mixing them; S204, adding 10-30 parts by mass of pyrite ore as core material into a disc pelletizing machine as core, adding water to wet the surface of the pyrite ore core material, and then using the mixed powder as a coating material, adding the mixed powder into the disc pelletizing machine batch by batch and spraying water, the total amount of water added is 20%-30% of the mixed powder; wherein, one batch of the mixed powder mixed with sulfur is added last as the outermost coating material of the biological filter material; S205, the powder to be mixed is formed into balls with pyrite ore as the core and the balls are taken out after the size reaches a preset size, spread at 20°C-25°C, sprayed with water, and naturally cured and aged for 28 days-30 days to obtain the coated sulfur-carrying mineral-based biofilter material.

3. The method for preparing a coated sulfur-carrying mineral-based biological filter material for simultaneous nitrogen and phosphorus removal from wastewater according to claim 1 or 2, characterized in that: The preset particle size of the selected pyrite ore is 1mm-9mm.

4. The method for preparing a coated sulfur-carrying mineral-based biological filter material for simultaneous nitrogen and phosphorus removal from wastewater according to claim 1 or 2, characterized in that: The powders are stirred and mixed by a stirring machine for more than 15 minutes until they are uniformly mixed.

5. The method for preparing a coated sulfur-carrying mineral-based biological filter material for simultaneous denitrification and dephosphorization of wastewater according to claim 1 or 2, characterized in that: The cement is ordinary Portland cement.

6. The method for preparing a coated sulfur-bearing mineral-based biological filter material for simultaneous denitrification and dephosphorization of wastewater according to claim 1 or 2, characterized in that: The gypsum is dihydrate gypsum.

7. The method for preparing a coated sulfur-carrying mineral-based biological filter material for simultaneous denitrification and dephosphorization of wastewater according to claim 1 or 2, characterized in that: The sulfur grade in the selected pyrite ore is above 18%.

8. A coated sulfur-bearing mineral-based biofilter material for simultaneous nitrogen and phosphorus removal from wastewater, wherein the coated sulfur-bearing mineral-based biofilter material is prepared by the method of claim 1 or 2, characterized in that: The coated sulfur-carrying mineral-based biological filter material comprises: 10-30 parts by weight of pyrite ore core material; The coating material comprises 3-10 parts by weight of sulfur, 20-50 parts by weight of sulfur concentrate, 15-20 parts by weight of cement, 1-3 parts by weight of gypsum, 1-3 parts by weight of lime, 1-3 parts by weight of diatomaceous earth and 5-50 parts by weight of fly ash.

9. An application of the coated sulfur-bearing mineral-based biofilter material for simultaneous nitrogen and phosphorus removal from wastewater according to claim 1 or 2, characterized in that: The coated sulfur-carrying mineral-based biological filter material is used in an anaerobic fluidized bed, and the added amount is 1 / 3-2 / 3 of the effective volume of the anaerobic fluidized bed.

Images