CN117209054A - Sulfur-based magnesium-containing autotrophic nitrogen and phosphorus removal biological carrier, and preparation method and application thereof - Google Patents

Abstract

The invention relates to a sulfur-based magnesium-containing autotrophic nitrogen and phosphorus removal biological carrier, and a preparation method and application thereof, and belongs to the field of water advanced treatment. The sulfur-based magnesium-containing autotrophic nitrogen and phosphorus removal biological carrier comprises a matrix material and an active material distributed in the matrix material and/or at least on part of the surface; the matrix material comprises elemental sulfur and sulfur-containing compounds; the active material comprises an alkaline magnesium-containing compound and/or a mineral containing an alkaline magnesium-containing compound. The sulfur-based magnesium-containing autotrophic nitrogen and phosphorus removal biological carrier has sulfur morphology which is easy to be utilized in the denitrification process and the capability of automatically adjusting the pH value of a system, realizes deep denitrification and removal of nitrogen, and the dissolved magnesium ions endow the carrier with the function of efficiently removing ammonia nitrogen and phosphate by improving the transfer efficiency of ammonia nitrogen into cells and forming phosphate-containing sediment. The sulfur-based alkaline magnesium-containing functional material provided by the invention can realize synergistic deep removal of nitrate nitrogen, ammonia nitrogen and phosphate when applied to scenes such as deep treatment or ecological buffer areas, and has wide application prospect.

Description

A sulfur-based magnesium-containing autotrophic nitrogen and phosphorus removal biological carrier and its preparation method and application

Technical field

The invention relates to the field of advanced water treatment. Specifically, it relates to a sulfur-based magnesium-containing autotrophic denitrification and phosphorus removal biological carrier capable of synergistic and efficient removal of nitrate nitrogen, ammonia nitrogen and phosphate, and its preparation method and application.

Background technique

Nitrogen, as one of the main causes of eutrophication of water bodies, has always received widespread attention. At present, the nitrogen capacity of ecological water bodies in most areas has become saturated and is on the verge of risk of eutrophication outbreak. The nutrient content (nitrate nitrogen, ammonia nitrogen and phosphate) in the secondary treatment effluent of the sewage treatment plant is relatively low, but it is enough to cause eutrophication of natural water bodies. In recent years, the water quality of some inland river basins and lakes has changed. The performance is becoming increasingly obvious. Due to the limited self-purification capacity of water bodies, the environmental capacity of such areas is becoming increasingly saturated. Gradually increasing the total nitrogen emission limit of surrounding sewage discharge units is a powerful measure to prevent further deterioration of water quality. As a result, total nitrogen emission standards for sewage treatment plants have been continuously improved. For example, in 2012, the total nitrogen was raised from the national standard of 15 mg·L ^-1 to 10 mg·L ^-1 . In 2020, the total nitrogen in the effluent will be required to reach 5 mg·L ^-1 before it can be discharged. Although sewage treatment plants continue to improve their standards, there is still a large gap between the quality of their effluent and natural water bodies. Especially for environmentally sensitive areas, in-depth treatment or the use of ecological buffer zones is generally required to close the gap between the quality of effluent water discharged from sewage treatment plants and the quality of natural water bodies. .

Sulfur autotrophic denitrification technology is a denitrification technology that has attracted much attention at present, mainly due to the low cost of elemental sulfur and its outstanding advantages as both an electron donor and a biological carrier. However, a key problem with this technology is that denitrification acid production will have a negative impact on microbial activity, and it is often necessary to add alkalinity to adjust the microbial growth environment.

The prior art discloses an autotrophic denitrification biological carrier (CN 208980406 U). The biological carrier is composed of sulfur and limestone (CaCO ₃ ). Its base is sulfur, and limestone particles are incorporated on the surface and inside to adjust the system pH and Supplementary carbon source, but this carrier has limited nitrate nitrogen removal capacity when used in advanced treatment systems; it also has no significant removal effect on residual ammonia nitrogen and phosphate in secondary effluent.

The prior art also discloses a slow-release electron donor and a method for using it to carry out deep denitrification of sewage (CN109879415B), as well as an active biological carrier for denitrification and phosphorus removal, its preparation method and its application (CN 109019877 B). Sulfur and siderite are physically fused together to create an integrated composite biological carrier with a new structure without changing its composition. The sulfur in this new structure can participate in the denitrification process to achieve deep denitrification, the siderite can assist in the automatic adjustment of pH, and the generated ferrous ions can be used for phosphorus removal and denitrification and denitrification processes. However, the removal of residual ammonia nitrogen in the secondary effluent still cannot be achieved.

It can be seen that there is currently no autotrophic denitrification and phosphorus removal biological carrier that can synergistically and efficiently remove nitrate nitrogen, ammonia nitrogen, and phosphate, and can be used for in-depth treatment or ecological buffer zones to meet the needs of downstream environmentally sensitive waters as receiving water bodies. need.

Contents of the invention

In order to solve the above-mentioned technical problems, the purpose of the present invention is to provide a sulfur-based magnesium-containing autotrophic denitrification and phosphorus removal biological carrier with synergistic and efficient removal of nitrate nitrogen, ammonia nitrogen, and phosphate, for use in deep treatment or ecological buffering areas, etc. to protect downstream environmentally sensitive waters.

The second object of the present invention is to provide a method for preparing a sulfur-based magnesium-containing autotrophic nitrogen and phosphorus removal biological carrier.

The third object of the present invention is to provide a sewage treatment device based on a sulfur-based magnesium-containing autotrophic nitrogen and phosphorus removal biological carrier.

The fourth object of the present invention is to provide a sewage treatment method based on sulfur-based magnesium-containing autotrophic nitrogen and phosphorus removal biological carriers.

To achieve the above object, the technical solution adopted by the present invention is: a sulfur-based magnesium-containing autotrophic denitrification and phosphorus removal biological carrier, including a matrix material and active materials distributed inside and/or at least on part of the surface of the matrix material.

The matrix material includes elemental sulfur and sulfur-containing compounds.

The active material includes a basic magnesium-containing compound and/or a mineral containing a basic magnesium-containing compound.

Preferably, the basic magnesium-containing compound includes magnesium carbonate and/or magnesium hydroxide.

Preferably, the mineral containing basic magnesium-containing compounds includes magnesite, dolomite, brucite or serpentine.

Preferably, the mass ratio of the matrix material to the active material is 50:1 to 1:8.

More preferably, the mass ratio of the matrix material to the active material is 10:1 to 1:4.

Preferably, the sulfur-based magnesium-containing autotrophic denitrification and phosphorus removal biological carrier is in the shape of a mass, block, spherical or irregular shape, with a maximum directional size of 1.5 to 12 mm.

More preferably, the particle size of the sulfur-based magnesium-containing autotrophic denitrification and phosphorus removal biological carrier is 2 to 6 mm.

A method for preparing a sulfur-based magnesium-containing autotrophic nitrogen and phosphorus removal biological carrier, including the following steps:

1) Melt the matrix material into a liquid state at 120~180℃;

2) Mix the molten matrix material and active material at 160-180°C, and maintain a stirring speed of 400-700 rpm for 30-300 seconds to obtain a uniform mixed liquid;

3) Control the dripping speed to 0.5~5L·min ^-1 , drop the resulting mixed solution drop by drop into the cooling water at 4~60°C, and cool and shape for 1~10 minutes;

4) Filter, place the obtained solid material in an oven, and dry it at 40-60°C for 12-48 hours to obtain the sulfur-based magnesium-containing autotrophic denitrification and phosphorus removal biological carrier.

Preferably, before the molten matrix material is mixed with the active material, the molten matrix material is subjected to impurity removal treatment.

More preferably, the impurity removal treatment specifically includes: filtering the molten matrix material in stages to remove impurities ≥0.8 μm in the molten matrix material.

Preferably, before the molten matrix material and the active material are mixed, the active material is crushed and screened.

More preferably, the crushing and screening treatment specifically includes: crushing the active material, passing it through a sieve of 60 to 300 mesh, and taking the residue.

A sewage treatment device based on a sulfur-based magnesium-containing autotrophic biological carrier for nitrogen and phosphorus removal, including: a packed bed or fixed bed filter filled with fillers.

The filler includes the above-mentioned sulfur-based magnesium-containing autotrophic nitrogen and phosphorus removal biological carrier.

Preferably, the filler accounts for 10 to 90% of the fixed bed filter volume.

A sewage treatment method based on a sulfur-based magnesium-containing autotrophic denitrification and phosphorus removal biological carrier. The above-mentioned sulfur-based magnesium-containing autotrophic denitrification and phosphorus removal biological carrier is used to denitrify the sewage and/or simultaneously remove ammonia nitrogen and phosphate. .

The beneficial effects of the present invention are:

1. The sulfur-based magnesium-containing autotrophic denitrification and phosphorus removal biological carrier provided by the present invention has a sulfur form that is easily utilized by the denitrification process and the ability to automatically adjust the pH value of the system, achieving deep denitrification and denitrification while having the ability to remove ammonia nitrogen. and phosphate functions.

2. The preparation method of the sulfur-based magnesium-containing autotrophic nitrogen and phosphorus removal biological carrier provided by the present invention is simple, easy to operate, does not require the use of more complicated instruments or equipment, and does not rely on special processes.

3. The sulfur-based magnesium-containing autotrophic denitrification and phosphorus removal biological carrier provided by the present invention mainly includes matrix materials and active materials. The elemental sulfur in the sulfur-based magnesium-containing autotrophic denitrification and phosphorus removal biological carrier prepared by the method of the present invention is The conversion from zero-valent sulfur to polysulfide and cyclic sulfur to linear sulfur is more conducive to the enrichment of denitrifying bacteria that use reduced sulfur as an electron donor, thereby enhancing nitrate removal.

4. When constructing a packed bed using the sulfur-based magnesium-containing autotrophic denitrification and phosphorus removal biological carrier provided by the present invention as filler, the alkaline components such as OH ^- and CO ₃ ^2- dissolved along with the denitrification process can adjust the system pH. Can handle sewage or waste water very well.

5. When constructing a packed bed using the sulfur-based magnesium-containing autotrophic denitrification and phosphorus removal biological carrier provided by the present invention as filler, the dissolved free magnesium ions can promote the absorption and utilization of ammonia nitrogen by nitrifying bacteria by improving the transport efficiency of ammonia nitrogen into cells. . These two aspects simultaneously contribute to the efficient removal of ammonia nitrogen in the system.

6. When constructing a packed bed using the sulfur-based magnesium-containing autotrophic denitrification and phosphorus removal biological carrier provided by the present invention as filler, the dissolved magnesium ions can combine with phosphate to form chemical sediments to achieve effluent phosphate control.

7. In the sewage treatment device provided by the present invention, sulfur-based magnesium-containing autotrophic denitrification and phosphorus removal biological carriers are filled as fillers in packed beds or fixed bed filters, which can achieve coordinated and efficient removal of nitrate, ammonia nitrogen and phosphate. , when the carrier needs to be replenished, filling can be completed conveniently and quickly, and the material has good uniformity.

8. The sewage treatment method provided by the present invention can achieve deep denitrification and have the synergistic deep removal effect of ammonia nitrogen and phosphate.

Description of the drawings

In order to more clearly explain the specific embodiments of the present invention or the technical solutions in the prior art, the drawings that need to be used in the description of the specific implementations or the prior art will be briefly introduced below. Obviously, the drawings in the following description The accompanying drawings illustrate some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without exerting creative efforts.

Figure 1 is a schematic structural diagram of the sulfur-based magnesium-containing autotrophic nitrogen and phosphorus removal biological carrier provided by the present invention.

Figure 2 is the surface scanning electron microscope (SEM) (a) and energy spectrum (EDS) (b) results of the sulfur-based magnesium-containing autotrophic denitrification and phosphorus removal biological carrier provided by the present invention.

Figure 3 is the photoelectron spectrum (XPS) characterization result of the sulfur-based magnesium-containing autotrophic denitrification and phosphorus removal biological carrier provided by the present invention.

Figure 4 is a schematic structural diagram of the sewage treatment device provided by the present invention.

Reference signs:

1-Water inlet device, 2-Backwash device, 3-Backwash air path and air inlet device, 4-Supporting filter plate, 5-Filling, 6-Water outlet, 7-Fixed bed filter.

Figure 5 is an SEM result of sediment collected after the sewage treatment device provided by the present invention has been operated for a period of time.

Detailed ways

The technical solutions of the present invention will be described clearly and completely below in conjunction with the accompanying drawings and specific implementation modes. However, those skilled in the art will understand that the embodiments described below are some of the embodiments of the present invention, and are not all embodiments. They are only used to illustrate the invention and should not be construed as limiting the scope of the invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention. If no specific conditions are specified in the examples, the experiments were carried out in accordance with conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not indicated, they are all conventional products that can be purchased commercially.

The first aspect of the present invention relates to a sulfur-based magnesium-containing autotrophic denitrification and phosphorus removal biological carrier, as shown in Figure 1, including a matrix material and activity distributed inside and/or at least on part of the surface of the matrix material. Material.

The matrix material includes elemental sulfur and sulfur-containing compounds.

The active material includes a basic magnesium-containing compound and/or a mineral containing a basic magnesium-containing compound.

Preferably, the basic magnesium-containing compound includes magnesium carbonate and/or magnesium hydroxide.

Preferably, the mineral containing basic magnesium-containing compounds includes magnesite, dolomite, brucite or serpentine.

The sulfur-based magnesium-containing autotrophic denitrification and phosphorus removal biological carrier has a sulfur form that is easily utilized by the denitrification process and the ability to automatically adjust the pH value of the system to achieve deep denitrification and denitrification while having the ability to remove ammonia nitrogen and phosphate. Function.

During the denitrification and denitrification process, the elemental sulfur on the surface of the sulfur-based magnesium-containing autotrophic denitrification and phosphorus removal biological carrier is consumed, reducing nitrate nitrogen into nitrogen gas to achieve the denitrification goal and releasing hydrogen ions at the same time. The hydrogen ions generated can dissolve carbonates/hydroxides and magnesium ions from basic magnesium-containing compounds and/or minerals containing basic magnesium-containing compounds. Among them, the former can automatically adjust the pH of the system and serve as a microbial carbon source; the latter can enhance ammonia nitrogen removal by accelerating the entry of ammonia nitrogen into nitrifying bacteria, and can also be combined with phosphate in the secondary effluent to form chemical sediments to achieve phosphate Remove.

Preferably, the mass ratio of the matrix material to the active material is 50:1 to 1:8.

More preferably, the mass ratio of the matrix material to the active material is 10:1 to 1:4 (for example, 10:1, 4:1, 2:1, 1:1 or 1:4).

By further optimizing the mass ratio of the matrix material and the active material, the amounts of hydrogen ions, magnesium ions and carbonates produced during the denitrification process are more reasonable, promoting the stable and long-lasting progress of the entire denitrification and phosphorus removal process.

Preferably, the sulfur-based magnesium-containing autotrophic denitrification and phosphorus removal biological carrier is in the shape of a mass, block, spherical or irregular shape, with a maximum directional size of 1.5 to 12 mm.

More preferably, the particle size of the sulfur-based magnesium-containing autotrophic denitrification and phosphorus removal biological carrier is 2 to 6 mm (for example, 2 mm, 3.5 mm, 4.5 mm, 5 mm or 6 mm).

The second aspect of the invention also relates to a method for preparing a sulfur-based magnesium-containing autotrophic denitrification and phosphorus removal biological carrier, which includes the following steps:

1) Melt the matrix material into a liquid state at 120-180°C (such as 120°C, 130°C, 140°C, 160°C or 180°C).

2) Mix the molten matrix material and the active material at 160-180°C (such as 160°C, 165°C, 170°C, 175°C or 180°C) and maintain 400-700rpm (such as 400rpm, 500rpm, 600rpm or 700rpm) The stirring speed is 30 to 300s (such as 30s, 50s, 80s, 100s, 150s, 180s, 200s, 230s, 260s or 300s) to obtain a uniform mixed liquid.

3) Control the dripping rate to 0.5~5L·min ^-1 (for example, 0.5L·min ^-1 , 0.8L·min ^-1 , 1.5L·min ^-1 , 2.5L·min ^-1 , 4L·min -1, ^5L ·min ^-1 ), drop the above mixed liquid dropwise into the cooling water at 4 to 60°C (such as 4°C, 10°C, 20°C, 40°C, 50°C or 60°C), and cool and shape for 1 to 10min (for example, 1min , 2min, 5min, 6min, 8min or 10min).

4) Filter, place the obtained solid material in an oven, and dry it at 40 to 60°C (for example, 40°C, 45°C, 50°C, 55°C or 60°C) for 12 to 48h (for example, 12h, 15h, 18h, 24h, 36h, 42h or 48h), the sulfur-based magnesium-containing autotrophic denitrification and phosphorus removal biological carrier is obtained.

Preferably, before the molten matrix material is mixed with the active material, the molten matrix material is subjected to impurity removal treatment.

More preferably, the impurity removal treatment specifically includes: melting the molten matrix material at 120-180°C (such as 120°C, 130°C, 140°C, 160°C or 180°C) and letting it stand. The molten matrix material is graded and filtered to remove impurities ≥0.8 μm in the molten matrix material.

Removing impurities in the matrix material can further increase the content of effective components and improve the denitrification ability of the autotrophic denitrification and phosphorus removal biological carrier.

Preferably, before the molten matrix material and the active material are mixed, the active material is crushed and screened.

More preferably, the crushing and screening process specifically includes: crushing the active material and passing it through a 60-300 mesh sieve (such as 60 mesh, 80 mesh, 100 mesh, 120 mesh, 140 mesh, 150 mesh, 160 mesh, 190 mesh). mesh, 220 mesh, 250 mesh, 280 mesh or 300 mesh), take the sieve residue and use the sieved active material as raw material.

Choosing the particle size of the active material within a reasonable range can ensure a tighter connection between the active material and the matrix material, and no delamination will occur during the denitrification process.

The third aspect of the present invention also relates to a sewage treatment device based on a sulfur-based magnesium-containing autotrophic denitrification and phosphorus removal biological carrier, including: a packed bed or a fixed bed filter filled with fillers.

The filler includes the above-mentioned sulfur-based magnesium-containing autotrophic nitrogen and phosphorus removal biological carrier.

The sewage treatment device has a good denitrification function.

Preferably, as shown in Figure 4, the sewage treatment device includes a water inlet device 1, a backwash device 2, a backwash air path and an air inlet device 3, a supporting filter plate 4, a filler 5, a water outlet 6 and a fixed bed. Filter 7.

Preferably, the bottom side wall of the fixed bed filter is provided with an air inlet and a water inlet.

Preferably, the air inlet device is connected to the air inlet of the fixed bed filter through the backwash air path.

Preferably, the water inlet device is connected to the water inlet of the fixed bed filter.

Preferably, the backwash water inlet at the bottom of the fixed bed filter and the water outlet of the backwash device are connected through a backwash water pipe.

Preferably, the supporting filter plate is placed inside the fixed bed filter.

Preferably, the supporting filter plate is placed above the air inlet and water inlet provided on the bottom side wall of the fixed bed filter.

Preferably, the filler is placed on the supporting filter plate.

Preferably, a backwash outlet and a rinse outlet are provided on the side wall of the top of the fixed bed filter.

Preferably, the filler accounts for 10 to 90% of the fixed bed filter volume.

The fourth aspect of the present invention also relates to a sewage treatment method based on a sulfur-based magnesium-containing autotrophic denitrification and phosphorus removal biological carrier. The above-mentioned sulfur-based magnesium-containing autotrophic denitrification and phosphorus removal biological carrier is used to denitrify the sewage. deal with.

The present invention will be further explained and described below in conjunction with specific examples and comparative examples.

Example 1

The sulfur-based magnesium-containing autotrophic denitrification and phosphorus removal biological carrier provided in this embodiment uses elemental sulfur and magnesium carbonate with a mass ratio of 10:1. The preparation method includes the following steps:

1) Add solid elemental sulfur into the heating kettle, heat and melt it at 140°C to form liquid elemental sulfur, and perform graded filtration of the liquid elemental sulfur to remove impurities with a particle size greater than 0.8 μm.

2) The temperature of the heating kettle is increased and maintained at 160°C, and the magnesium carbonate that has been screened through a 120-mesh sieve is added to the liquid elemental sulfur in the heating kettle; the temperature in the heating kettle is controlled at 160°C, and the magnesium carbonate and The mixture of elemental sulfur was stirred and mixed at a frequency of 600 rpm for 50 s to obtain a uniform mixed liquid.

3) Keep the dripping speed at 1.5L·min ^-1 , drop the above mixture into the cooling water at 10°C drop by drop, and cool and shape for 1 minute to form solid spherical particles.

4) Filter, place the solid spherical particles in an oven, and dry at 40°C for 12 hours to obtain a sulfur-based magnesium-containing autotrophic denitrification and phosphorus removal biological carrier with a particle size of 3 to 4 mm.

Example 2

The sulfur-based magnesium-containing autotrophic denitrification and phosphorus removal biological carrier provided in this embodiment uses elemental sulfur and magnesite (magnesium carbonate content is about 90%) with a mass ratio of 10:1. The preparation method includes the following steps:

1) Add solid elemental sulfur into the heating kettle, heat and melt it at 160°C to form liquid elemental sulfur, and perform graded filtration of the liquid elemental sulfur to remove impurities with a particle size greater than 0.8 μm.

2) The temperature of the heating kettle is increased and maintained at 180°C, and the magnesite that has been screened through a 250-mesh sieve is added to the liquid elemental sulfur in the heating kettle; the temperature in the heating kettle is controlled at 180°C, and the magnesite is The mixture of ore and elemental sulfur was stirred and mixed at a frequency of 700 rpm for 150 s to obtain a uniform mixed liquid.

3) Keep the dripping speed at 1.5L·min ^-1 , drop the above mixed liquid into the cooling water at 20°C drop by drop, and cool and shape for 6 minutes to form solid spherical particles.

4) Filter, place the solid spherical particles in an oven, and dry at 55°C for 24 hours to obtain the sulfur-based magnesium-containing autotrophic denitrification and phosphorus removal biological carrier with a particle size of 3 to 4 mm.

Example 3

The sulfur-based magnesium-containing autotrophic denitrification and phosphorus removal biological carrier provided in this example uses elemental sulfur and magnesite (magnesium carbonate content is about 90%) with a mass ratio of 4:1. The preparation method is the same as in Example 2 to obtain sulfur It is a magnesium-based autotrophic biological carrier for nitrogen and phosphorus removal, with a particle size of 3 to 4 mm.

Example 4

The sulfur-based magnesium-containing autotrophic denitrification and phosphorus removal biological carrier provided in this embodiment uses elemental sulfur and magnesite (magnesium carbonate content is about 90%) with a mass ratio of 1:1. The preparation method includes the following steps:

1) Add solid elemental sulfur into the heating kettle, heat and melt it at 120°C to form liquid elemental sulfur, and perform graded filtration of the liquid elemental sulfur to remove impurities with a particle size greater than 0.8 μm.

2) Increase the temperature of the heating kettle and maintain it at 175°C. Add the unscreened magnesite that has been screened through a 160-mesh sieve to the liquid elemental sulfur in the heating kettle; control the temperature in the heating kettle to 175°C and add the magnesite The mixture of ore and elemental sulfur was stirred and mixed at a frequency of 400 rpm for 300 s to obtain a uniform mixed liquid.

3) Keep the dripping speed at 1.5L·min ^-1 , drop the above mixed liquid into the cooling water at 4°C drop by drop, and cool and shape for 10 minutes to form solid spherical particles.

4) Filter, place the solid spherical particles in an oven, and dry at 60°C for 18 hours to obtain the sulfur-based magnesium-containing autotrophic denitrification and phosphorus removal biological carrier with a particle size of 3 to 4 mm.

Example 5

The sulfur-based magnesium-containing autotrophic denitrification and phosphorus removal biological carrier provided in this embodiment uses elemental sulfur and magnesite (magnesium carbonate content is about 90%) with a mass ratio of 1:4. The preparation method includes the following steps:

1) Add solid elemental sulfur into the heating kettle, heat and melt it at 180°C to form liquid elemental sulfur, and perform graded filtration of the liquid elemental sulfur to remove impurities with a particle size greater than 0.8 μm.

2) The temperature of the heating kettle is maintained at 180°C, and the magnesite that has been screened through a 300-mesh sieve is added to the liquid elemental sulfur in the heating kettle; the temperature in the heating kettle is controlled at 180°C, and the magnesite and The sulfur mixture was stirred at a frequency of 500 rpm for 200 s to obtain a uniform mixture.

3) Keep the dripping speed at 1.5L·min ^-1 , drop the above mixed liquid into the cooling water at 50°C drop by drop, and cool and shape for 5 minutes to form solid spherical particles.

4) Filter, place the solid spherical particles in an oven, and dry at 50°C for 42 hours to obtain the sulfur-based magnesium-containing autotrophic denitrification and phosphorus removal biological carrier with a particle size of 3 to 4 mm.

As shown in (a) of Figure 2, the sulfur-based magnesium-containing autotrophic denitrification and phosphorus removal biological carrier provided by the present invention exhibits a nanoflower structure microscopically, and the gaps formed by the overlapping of sheets endow the material with a larger specific surface area and higher density. Multiple active sites; the EDS results shown in Figure 2 (b) show that the carrier is based on elemental sulfur, and the nanoflowers embedded on it are mainly formed by most active materials doped with a small amount of elemental sulfur.

As shown in Figure 3, the results show that the sulfur-based magnesium-containing autotrophic denitrification and phosphorus removal biological carrier provided by the present invention has polysulfide and linear sulfur forms that are easily absorbed and utilized by microorganisms.

Example 6 A wastewater treatment method based on sulfur-based magnesium-containing autotrophic nitrogen and phosphorus removal biological carriers

A sewage treatment method based on sulfur-based magnesium-containing autotrophic denitrification and phosphorus removal biological carriers, using a sewage treatment device as shown in Figure 4, including a water inlet device 1, a backwash device 2, a backwash gas path and an air inlet device 3. Support filter plate 4, filler 5, water outlet 6 and fixed bed filter 7.

The bottom of the side wall of the fixed bed filter 7 is provided with an air inlet and a water inlet; the backwash air path and the air inlet device 3 are connected to the air inlet of the fixed bed filter 7; the water inlet device 1 is connected to the air inlet of the fixed bed filter 7. The water inlet of the fixed bed filter 7 is connected; the backwash water inlet at the bottom of the fixed bed filter 7 is connected to the water outlet of the backwash device 2; the supporting filter plate 4 is placed on the fixed bed filter. Inside the pool 7; the supporting filter plate 4 is placed at the bottom of the side wall of the fixed bed filter 7 and is arranged above the air inlet and water inlet; the filler 5 is placed on the supporting filter plate 4 ; The top side wall of the fixed bed filter 7 is provided with an outlet 6.

(1) Effects of sulfur-based magnesium-containing autotrophic nitrogen and phosphorus removal biological carriers prepared at different dripping rates on the removal of nitrate nitrogen, ammonia nitrogen and total phosphorus

1. Sulfur-based magnesium-containing autotrophic nitrogen and phosphorus removal biological carrier, the preparation method is as follows:

The sulfur-based magnesium-containing autotrophic denitrification and phosphorus removal biological carrier provided in this example uses elemental sulfur and magnesite (magnesium carbonate content is about 90%) with a mass ratio of 1:1. The preparation method is the same as in Example 4, with different points. The only thing is that by controlling the dripping rate as shown in Table 1, sulfur-based magnesium-containing autotrophic denitrification and phosphorus removal biological carriers prepared at different dripping rates were obtained.

2. Methods for removing nitrate nitrogen, ammonia nitrogen and total phosphorus

The sulfur-based magnesium-containing autotrophic denitrification and phosphorus removal biological carriers prepared at different dripping rates were placed as fillers 5 in the fixed bed filter 7 of the sewage treatment device provided in Figure 4, with a filling ratio of 70%, and to the fixed bed filter 7. Anaerobic sludge from a certain sewage treatment plant was added to the bed filter 7, soaked for 24 hours, and then started with water flow. During the start-up process, the hydraulic retention time of the fixed-bed filter reactor is set to 1 hour, and the water containing culture medium (including nitrate nitrogen, ammonia nitrogen, phosphorus, etc.) is stably transported into the reactor using a peristaltic pump. Carry out dynamic culture and acclimation, and take samples for testing every 24 hours until the concentrations of nitrate nitrogen, ammonia nitrogen and phosphorus in the effluent reach stability. The nitrate nitrogen concentration in the simulated wastewater is 30 mg L ^-1 , the ammonia nitrogen concentration is 4 mg L ^-1 , the total phosphorus concentration is 3.5 mg L ^-1 , and the inlet water pH is 7.52±0.10. The concentrations of nitrate nitrogen, ammonia nitrogen and total phosphorus in the device effluent were measured respectively, and the results of the removal rates of nitrate nitrogen, ammonia nitrogen and total phosphorus are shown in Table 1.

Table 1 Nitrate nitrogen, ammonia nitrogen and total phosphorus removal rates of sulfur-based magnesium-containing autotrophic denitrification and phosphorus removal biological carriers formed at different mixing liquid drop rates

(2) Effects of different sulfur-based magnesium-containing autotrophic nitrogen and phosphorus removal biological carriers on the removal of nitrate nitrogen, ammonia nitrogen and total phosphorus

1. Comparative Example 1

Compared with Example 1, the sulfur autotrophic denitrification and phosphorus removal biological carrier provided in this comparative example only differs in that it only consists of the matrix material elemental sulfur, and no active materials (alkaline magnesium-containing compounds and/or alkaline-containing compounds) are added. magnesium compound mineral).

2. Comparative Example 2

This comparative example is Embodiment 1 of the prior art CN109019877B.

3. Methods for removing nitrate nitrogen, ammonia nitrogen and total phosphorus

The autotrophic denitrification and phosphorus removal biological carriers prepared in Examples 1 to 5, Comparative Example 1 and Comparative Example 2 were used as fillers 5 and placed in the fixed bed filter 7 of the sewage treatment device as shown in Figure 4. The filling ratio is 70%, add anaerobic sludge from a certain sewage treatment plant to the fixed bed filter 7, soak for 24 hours and then start flowing water. During the start-up process, the hydraulic retention time of the fixed-bed filter reactor is set to 1 hour, and the water containing culture medium (including nitrate nitrogen, ammonia nitrogen, phosphorus, etc.) is stably transported into the reactor using a peristaltic pump. Carry out dynamic culture and acclimation, and take samples for testing every 24 hours until the concentrations of nitrate nitrogen, ammonia nitrogen and phosphorus in the effluent reach stability. The nitrate nitrogen concentration in the simulated wastewater is 30 mg L ^-1 , the ammonia nitrogen concentration is 4 mg L ^-1 , the total phosphorus concentration is 3.5 mg L ^-1 , and the inlet water pH is 7.52±0.10. The concentrations of nitrate nitrogen, ammonia nitrogen and total phosphorus in the effluent of the device were measured respectively. The results of the removal rates of nitrate nitrogen, ammonia nitrogen and total phosphorus and the pH of the effluent are shown in Table 2.

Table 2 Nitrate nitrogen, ammonia nitrogen and total phosphorus removal rates and effluent pH

Nitrate nitrogen removal rate Ammonia nitrogen removal rate Total phosphorus removal rate Effluent pH Example 1 80.7±3.9% 52.1±3.1% 22.5±1.4% 7.31±0.11 Example 2 72.2±1.9% 62.7±3.6% 39.6±2.1% 7.35±0.17 Example 3 90.9±3.2% 85.6±4.2% 60.1±4.2% 7.35±0.12 Example 4 87.3±2.4% 72.3±2.8% 57.2±3.4% 7.29±0.23 Example 5 92.1±2.2% 98.1±1.5% 70.1±3.6% 7.31±0.14 Comparative example 1 58.2±1.4% not removed 10.2±3.2% 6.98±0.13 Comparative example 2 84.3±5.7% not removed 76.0±8.0% 7.01±0.11

During the continuous flow of water, a stable biofilm gradually grows on the surface of the sulfur-based magnesium-containing autotrophic denitrification and phosphorus removal biological carrier, and the nitrate nitrogen and ammonia nitrogen removal capabilities gradually increase. Among them, the effluent nitrate removal rate of Example 5 is 92.1±2.2%. Compared with the nitrate removal rate of Comparative Example 1, the nitrate removal rate is increased by 33.9%. Compared with the removal effect of Comparative Example 2, the nitrate removal rate is increased by 7.8%. ; The effluent ammonia nitrogen removal rate of Example 5 is 98.1 ± 1.5%, while Comparative Example 1 and Comparative Example 2 have no obvious removal of ammonia nitrogen; the total phosphorus removal rate of the effluent of Example 5 is 70.1 ± 3.6%; the effluent of Example 5 The pH can be maintained at 7.31±0.14, which is beneficial to the denitrification and phosphorus removal processes.

It can be seen from this that when the sulfur-based magnesium-containing autotrophic denitrification and phosphorus removal biological carrier of the present invention is filled in a fixed bed filter, the nanoflower structure of the sulfur-based magnesium-containing autotrophic denitrification and phosphorus removal biological carrier gives it a large specific surface area and More active sites (Fig. 2). In addition, the released alkaline components such as OH ^- and CO ₃ ^2- can achieve automatic balance of pH, thereby conducive to the enrichment and growth of more microorganisms; prepared by the method of the present invention In the obtained sulfur-based magnesium-containing autotrophic denitrification and phosphorus removal biological carrier, the sulfur is converted from zero-valent sulfur to polysulfide, and the cyclic sulfur is converted to linear sulfur (Figure 3), which is more conducive to using reduced sulfur as an electron donor. The enrichment of denitrifying bacteria gives the sulfur-based magnesium-containing autotrophic denitrification and phosphorus removal biological carrier stable and high denitrification efficiency. When the efficiency of the sulfur-based magnesium-containing autotrophic denitrification and phosphorus removal biological carriers declines due to consumption, just supplement the prepared active biological carriers to restore the bed to its original height, without the need for additional operations such as mixing.

The sulfur-based magnesium-containing autotrophic denitrification and phosphorus removal biological carrier provided by the invention has both the efficient removal ability of ammonia nitrogen and total phosphorus: a packed bed is constructed using the sulfur-based magnesium-containing autotrophic denitrification and phosphorus removal biological carrier provided by the invention as filler. When the solution is released, the dissolved free magnesium ions can promote the absorption and utilization of ammonia nitrogen by nitrifying bacteria by improving the transport efficiency of ammonia nitrogen into the cells; as shown in Figure 5, the dissolved magnesium ions can combine with phosphate to form chemical sediments to achieve effluent phosphate control. The application prospects are broad.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention, but not to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: It is still possible to modify the technical solutions recorded in the foregoing embodiments, or to equivalently replace some or all of the technical features; and these modifications or substitutions do not deviate from the essence of the corresponding technical solutions from the technical solutions of the various embodiments of the present invention. range.

Claims (10)

1. A sulfur-based magnesium-containing autotrophic nitrogen and phosphorus removal biological carrier, characterized in that the sulfur-based magnesium-containing autotrophic nitrogen and phosphorus removal biological carrier comprises a matrix material and an active material distributed inside and/or at least on part of the surface of the matrix material;

the matrix material comprises elemental sulfur and sulfur-containing compounds;

the active material comprises an alkaline magnesium-containing compound and/or a mineral containing an alkaline magnesium-containing compound.

2. A sulfur-based magnesium-containing autotrophic nitrogen and phosphorus removal biological carrier according to claim 1, wherein said basic magnesium-containing compound comprises magnesium carbonate and/or magnesium hydroxide; the minerals containing basic magnesium-containing compounds include magnesite, dolomite, brucite or serpentine.

3. The sulfur-based magnesium-containing autotrophic nitrogen and phosphorus removal biological carrier according to claim 1, wherein the mass ratio of the matrix material to the active material is 50:1-1:8;

preferably, the mass ratio of the matrix material to the active material is 10:1-1:4.

4. The sulfur-based magnesium-containing autotrophic nitrogen and phosphorus removal biological carrier according to claim 1, wherein the sulfur-based magnesium-containing autotrophic nitrogen and phosphorus removal biological carrier is in a shape of a lump, a block, a sphere or an irregular shape, and the maximum directional size is 1.5-12 mm;

preferably, the particle size of the sulfur-based magnesium-containing autotrophic nitrogen and phosphorus removal biological carrier is 2-6 mm.

5. The method for preparing the sulfur-based magnesium-containing autotrophic nitrogen and phosphorus removal biological carrier as claimed in any one of claims 1 to 4, which is characterized by comprising the following steps:

1) Melting the matrix material into a liquid state at 120-180 ℃;

2) Mixing the molten matrix material and the active material at 160-180 ℃, and maintaining the stirring speed of 400-700 rpm for 30-300 s to obtain uniform mixed solution;

3) Controlling the dripping speed to be 0.5-5 L.min ^-1 Dropwise adding the obtained mixed solution into cooling water at the temperature of 4-60 ℃, and cooling and molding for 1-10 min;

4) Filtering, putting the obtained solid substance into a baking oven, and drying for 12-48 h at 40-60 ℃ to obtain the sulfur-based magnesium-containing autotrophic nitrogen and phosphorus removal biological carrier.

6. The method according to claim 5, wherein the molten matrix material is subjected to a impurity removal treatment before being mixed with the active material;

preferably, the impurity removing treatment specifically includes: and (3) classifying and filtering the molten matrix material to remove impurities which are more than or equal to 0.8 mu m in the molten matrix material.

7. The method according to claim 5, wherein the active material is subjected to a pulverizing and sieving treatment before the matrix material in the molten state is uniformly mixed with the active material;

preferably, the crushing and screening treatment specifically includes: crushing the active material, sieving with a 60-300 mesh sieve, and taking out the undersize.

8. A sewage treatment device based on sulfur-based magnesium-containing autotrophic nitrogen and phosphorus removal biological carriers, which is characterized in that the sewage treatment device comprises: a packed bed or fixed bed filter filled with a filler;

the filler comprises the sulfur-based magnesium-containing autotrophic nitrogen and phosphorus removal biological carrier as claimed in any one of claims 1 to 4.

9. The wastewater treatment apparatus according to claim 8, wherein the packing occupies 10 to 90% of the volume of the fixed bed filter.

10. A sewage treatment method based on sulfur-based magnesium-containing autotrophic nitrogen and phosphorus removal biological carriers, which is characterized in that the sulfur-based magnesium-containing autotrophic nitrogen and phosphorus removal biological carriers are utilized to perform denitrification treatment and/or synchronous ammonia nitrogen and phosphate removal on sewage.