A wastewater treatment device and method for enhanced biological nitrogen and phosphorus removal

Abstract

The present invention discloses a wastewater treatment device and a wastewater treatment method for enhanced biological nitrogen and phosphorus removal. Inside the reactor housing, it is divided into a first reactor zone and a second reactor zone. An overflow baffle is provided at the outlet end of the first reactor zone. The inlet of the second reactor zone is located at the bottom and downstream of the overflow baffle. In the first reactor zone, an inlet, a cobblestone support layer, a bluestone layer, a pyrite layer, and a sludge mixing zone are sequentially arranged from bottom to top. A sulfur layer is provided in the second reactor zone. The bluestone layer provides an inorganic carbon source (carbonate radical) and calcium ions, providing a substrate for the removal of phosphate radicals. At the same time, the carbonate radical can play the role of buffering pH adjustment. The pyrite provides iron ions with different valence states and sulfur ions with low valence states, providing a substrate for the removal of nitrate radicals and total phosphorus.

Description

Technical Field

[0001] The invention belongs to the technical field of wastewater treatment, and particularly relates to a wastewater treatment device and a wastewater treatment method for enhanced biological nitrogen and phosphorus removal. Background Art

[0002] Disclosing the information of this background art section is only intended to enhance the understanding of the overall background of the present invention, and is not necessarily regarded as an admission or any form of implication that this information constitutes the prior art already known to those of ordinary skill in the art.

[0003] Water eutrophication is a global phenomenon in recent years. The fundamental reason is the increase in the nutrient elements nitrogen and phosphorus in the discharged wastewater. Although the biochemical treatment in sewage treatment plants can reduce most pollutants, the concentrations of total nitrogen and total phosphorus at the discharge outlet are still very high. In most cases, the discharge concentrations (mainly referring to phosphate and nitrate nitrogen) of the secondary effluent after biochemical system treatment are still higher than the indicators of water eutrophication and the required indicators at the discharge outlet. For high-total-nitrogen industrial wastewater or municipal sewage, tertiary advanced treatment is carried out, and denitrification is carried out by adding carbon sources to reduce total nitrogen. The operating cost of carbon source chemicals is high. Total phosphorus is removed by phosphorus-removing chemicals. The operating cost of the entire nitrogen and phosphorus process section is high. At the same time, it is still difficult to ensure the discharge data for areas with high effluent standards. Moreover, the entire wastewater treatment system has a large floor area, a long construction period, it is difficult for manual labor to control the dosage of chemicals added, and it is difficult to ensure the effluent indicators. Summary of the Invention

[0004] In view of the technical problems existing in the prior art, the present invention provides a wastewater treatment device and a wastewater treatment method for enhanced biological nitrogen and phosphorus removal.

[0005] To solve the above technical problems, the following one or more embodiments of the present invention provide the following technical solutions:

[0006] In a first aspect, the present invention provides a wastewater treatment device for enhanced biological nitrogen and phosphorus removal. Inside the reactor housing, it is divided into a first reactor area and a second reactor area. An overflow baffle is provided at the outlet end of the first reactor area. The inlet of the second reactor area is located at the bottom and downstream of the overflow baffle;

[0007] In the first reactor area, a water inlet, a cobblestone support layer, a bluestone layer, a pyrite layer, and a sludge mixing area are sequentially arranged from bottom to top;

[0008] A sulfur layer is provided inside the second reactor area.

[0009] In a second aspect, the present invention provides a wastewater treatment method for enhanced biological nitrogen and phosphorus removal, including the following steps:

[0010] The wastewater to be treated flows upward through the cobblestone support layer, the bluestone layer, and the pyrite layer in sequence. The bluestone layer provides inorganic carbon sources (carbonate ions) and calcium ions, providing substrates for the removal of phosphate ions. At the same time, the carbonate ions can be used to adjust the pH value. The pyrite provides iron ions with different valence states and sulfur ions with low valence states, providing substrates for the removal of nitrate ions and total phosphorus. Under the action of the formed autotrophic denitrification-dominated microbial community, phosphorus and nitrogen removal are achieved;

[0011] The wastewater after phosphorus and nitrogen removal then flows through the sulfur layer for further purification before being discharged.

[0012] Compared with the prior art, the above one or more technical solutions of the present invention have achieved the following beneficial effects:

[0013] The bluestone layer provides inorganic carbon sources (carbonate ions) and calcium ions, providing substrates for the removal of phosphate ions. At the same time, the carbonate ions can be used to adjust the pH value. The pyrite provides iron ions with different valence states and sulfur ions with low valence states, providing substrates for the removal of nitrate ions and total phosphorus. By providing substrates required by autotrophic denitrifying microorganisms through the packing layer, the activity of autotrophic microorganisms is gradually stimulated. Based on traditional denitrification, the proportion of autotrophic denitrifying microorganisms is increased, and an autotrophic denitrification-dominated microbial community is formed through gradual domestication. When using this autotrophic denitrification-dominated microbial community to treat wastewater, better nitrogen and phosphorus removal effects can be obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The specification drawings forming a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention.

[0015] Figure 1 It is a schematic diagram of the overall structure of the nitrogen and phosphorus removal system according to an embodiment of the present invention.

[0016] Among them, 1-concrete foundation, 2-inlet, 3-cobblestone support layer, 4-bluestone layer, 5-pyrite layer, 6-sludge mixing area, 7-first area discharge and maintenance opening, 8-first observation port, 9-overflow baffle, 10-first area feeding and maintenance opening, 11-reactor first area, 12-second area feeding and maintenance opening, 13-second observation port, 14-second area discharge and maintenance opening, 15-sulfur layer, 16-outlet, 17-reactor second area. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0017] It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0018] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they specify the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0019] In a first aspect, the present invention provides a wastewater treatment device for enhanced biological nitrogen and phosphorus removal. The interior of the reactor housing is divided into a first reactor zone and a second reactor zone. An overflow baffle is provided at the outlet end of the first reactor zone, and the inlet of the second reactor zone is located at the bottom and downstream of the overflow baffle.

[0020] In the first reactor zone, an inlet, a cobblestone support layer, a bluestone layer, a pyrite layer, and a sludge mixing zone are sequentially arranged from bottom to top.

[0021] A sulfur layer is provided in the second reactor zone.

[0022] In some embodiments, the cobblestones in the cobblestone support layer have a particle size of 10 - 20 mm. The cobblestone support layer serves to support the upper weight and distribute water evenly.

[0023] Furthermore, the thickness of the cobblestone support layer is 100 - 550 mm.

[0024] In some embodiments, in the bluestone layer, the bluestones have a particle size of 5 - 8 mm.

[0025] Furthermore, the bluestone layer accounts for 5 - 15% of the volume of the first reactor zone. There are enough bluestones in the bluestone layer to ensure sufficient inorganic carbon source and calcium ions for the wastewater to be treated.

[0026] In some embodiments, the pyrite in the pyrite layer has a particle size of 2 - 4 mm.

[0027] Furthermore, the thickness of the pyrite layer is 300 - 2000 mm.

[0028] In some embodiments, a cobblestone support layer is provided at the bottom of the second reactor zone, and the cobblestone support layer is located below the sulfur layer.

[0029] Furthermore, the thickness of the sulfur layer is 50 - 100 mm.

[0030] In some embodiments, the volume ratio of the first reactor zone to the second reactor zone is 2 - 10:1.

[0031] In some embodiments, maintenance openings and observation openings are provided on the side walls of the housing corresponding to the first reactor zone and the second reactor zone.

[0032] Furthermore, feeding and maintenance openings are provided at the tops of the shells corresponding to the first reaction zone and the second reaction zone of the reactor.

[0033] Second, the present invention provides a wastewater treatment method for enhanced biological nitrogen and phosphorus removal, comprising the following steps:

[0034] The wastewater to be treated flows upward successively through a cobblestone support layer, a bluestone layer, and a pyrite layer. The bluestone layer provides an inorganic carbon source and calcium ions, providing a substrate for the removal of phosphate radicals. The pyrite provides iron ions with different valence states and sulfur ions with low valence states, providing a substrate for the removal of nitrate radicals and total phosphorus. Under the action of the formed autotrophic denitrification-dominated microbial community, phosphorus and nitrogen removal are achieved.

[0035] The wastewater after phosphorus and nitrogen removal then flows through a sulfur layer for further purification and is discharged.

[0036] In some embodiments, the residence time of the wastewater to be treated in the first reaction zone of the reactor is 2 - 4 h, and the residence time in the second reaction zone of the reactor is 0.2 - 0.5 h.

[0037] Example

[0038] The wastewater treatment device for enhanced biological nitrogen and phosphorus removal includes a reactor body and a concrete foundation 1. The inside of the reactor shell is partitioned into a first reaction zone 11 and a second reaction zone 17. An overflow baffle 9 is provided at the outlet end of the first reaction zone 11. The inlet of the second reaction zone 17 is located at the bottom and downstream of the overflow baffle 9. In the first reaction zone 11, a water inlet 2, a cobblestone support layer 3, a bluestone layer 4, a pyrite layer 5, and a sludge mixing zone 6 are successively arranged from bottom to top. A sulfur layer 15 is arranged in the second reaction zone 17.

[0039] The cobblestones in the cobblestone support layer 3 have a particle size of 10 - 20 mm; the thickness of the cobblestone support layer 3 is 450 mm. In the bluestone layer 4, the bluestones have a particle size of 5 - 8 mm, and the bluestone layer 4 accounts for 10% of the volume of the first reaction zone 11. In the pyrite layer 5, the pyrite has a particle size of 2 - 4 mm, and the thickness of the pyrite layer 5 is 1000 mm. A cobblestone support layer 3 is provided at the bottom of the second reaction zone 17. The cobblestone support layer 3 is located below the sulfur layer 15. The thickness of the sulfur layer 15 is 80 mm, accounting for 3% of the total volume of the second reaction zone 17.

[0040] The volume ratio of the reactor zone 11 and the reactor zone 2 17 is 8:1; the shell side walls corresponding to the reactor zone 11 and the reactor zone 2 17 are provided with inspection ports (the zone 1 material discharging inspection port 7, the zone 2 material discharging inspection port 14) and observation ports (the first observation port 8, the second observation port 13). The tops of the shells corresponding to the reactor zone 11 and the reactor zone 2 17 are provided with feeding inspection ports (the zone 1 material feeding inspection port 10, the zone 2 material feeding inspection port 12). The side wall of the reactor zone 2 is provided with a water outlet 16, which is located above the sulfur layer 15.

[0041] The equipment is a skid-mounted device that can be processed in batches in the factory. Depending on the water volume of the project, several reactors can be connected in series or in parallel to feed water in stages. Pipeline docking can be carried out directly on the project site, saving construction period. This process is suitable for deep nitrogen and phosphorus removal at the end of low carbon-nitrogen ratio industrial water or municipal water.

[0042] Wastewater enters through the lower part, passes through the pebble supporting layer 3 from the water inlet 2, and uses pebbles of different particle sizes to support the upper weight and evenly distribute water. At the same time, pebbles are cheap, which is conducive to reducing project costs; it passes through the bluestone layer 4 and the pyrite layer 5 in turn, wherein the bluestone layer 4 provides an inorganic carbon source (carbonate) and calcium ions, providing a substrate for the removal of phosphate, and at the same time, the carbonate can play the purpose of buffering pH adjustment, and the pyrite provides iron ions of different valence states and low-valence sulfur ions, providing a substrate for the removal of nitrate and total phosphorus; the reaction substrate introduced into the wastewater enters the sludge mixing zone 6, and provides the substrate required by the autotrophic denitrifying microorganisms through the filler layer, gradually stimulating the activity of autotrophic microorganisms, and increasing the proportion of autotrophic denitrifying microorganisms on the basis of traditional denitrification. After gradual domestication, a microbial community dominated by autotrophic denitrification is formed (during the domestication process, it can be To treat wastewater, in the early stage of domestication, the requirement of total nitrogen at the outlet will ensure the appropriate amount of carbon source. As time goes by, the autotrophic organisms are activated, and the amount of carbon source is continuously reduced to the normal water inlet level. The entire removal process is a collaborative treatment of autotrophic and heterotrophic types, but at different stages, the dominant bacterial community is different. At the same time, the entire autotrophic microorganism is stimulated by the sulfur source and starts very quickly, about 2 days, which is why a certain amount of sulfur is guaranteed in the system for rapid startup. In the later stage, it mainly depends on the role of pyrite); the effluent from the reactor in zone 1 can meet the requirements of total nitrogen ≤15mg / L and total phosphorus ≤0.5mg / L. Further, as a guarantee section, the wastewater flows by gravity through the reactor zone 2 17, and passes through the pebble support layer 3 and the sulfur layer 15 from bottom to top, where the sulfur comes from the biogas desulfurization in the anaerobic section of the wastewater, thereby realizing the recycling of resources.

[0043] A certain municipal water has a secondary effluent with a COD of 30 - 40 mg / L, a total nitrogen of 20 - 30 mg / L, and a total phosphorus of 1 - 4 mg / L. There is pressure on total nitrogen and total phosphorus (the discharge outlet requires a total nitrogen ≤ 15 mg / L and a total phosphorus ≤ 0.5 mg / L), and tertiary advanced treatment is carried out for connection; the autotrophic microorganisms start within 7 days and achieve stable operation within 35 days. The residence time in the first zone of the reactor is 3 h, and the residence time in the second zone of the reactor is 0.25 h. The total nitrogen in the effluent from the first zone is 8 - 12 mg / L, and the total phosphorus is 0.11 - 0.4 mg / L. The total nitrogen in the effluent from the second zone is 0.22 - 4 mg / L, and the total phosphorus is 0.11 - 0.3 mg / L.

[0044] A certain industrial water has a secondary effluent with a COD of 300 - 400 mg / L and a total nitrogen of 90 - 120 mg / L. There are problems such as difficult degradation of COD, supplementing glucose to reduce total nitrogen, high operating costs of the carbon source (the carbon-nitrogen ratio reaches 4 - 6:1), and a large amount of aerobic sludge production, while the total nitrogen at the discharge outlet does not meet the standard (the discharge outlet requires a total nitrogen ≤ 70 mg / L); after connecting to the reactor, the residence time in the first zone of the reactor is 4 h, and the residence time in the second zone of the reactor is 0.25 h. The carbon-nitrogen ratio is controlled at 0.8 - 1.6, the sludge production is reduced by about 65%, the operating cost is reduced by 50 - 60%, and the total nitrogen in the effluent from the first zone is 40 - 60 mg / L. Since the effluent from the first zone meets the effluent requirements, it directly bypasses the second zone to the outlet, and the second zone serves as a guarantee process.

[0045] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A wastewater treatment device for enhanced biological nitrogen and phosphorus removal, characterized in that: The interior of the reactor housing is partitioned into a first reactor zone and a second reactor zone. An overflow baffle is provided at the outlet end of the first reactor zone, and the inlet of the second reactor zone is located at the bottom and downstream of the overflow baffle; In the first reactor zone, an inlet, a cobblestone support layer, a bluestone layer, a pyrite layer, and a sludge mixing zone are sequentially arranged from bottom to top; A sulfur layer is provided in the second reactor zone; The cobblestones in the cobblestone support layer have a particle size of 10 - 20 mm; The thickness of the cobblestone support layer is 100 - 550 mm; In the bluestone layer, the bluestones have a particle size of 5 - 8 mm; The bluestone layer accounts for 5 - 15% of the volume of the first reactor zone; The pyrite in the pyrite layer has a particle size of 2 - 4 mm; The thickness of the pyrite layer is 300 - 2000 mm; A cobblestone support layer is provided at the bottom of the second reactor zone, and the cobblestone support layer is located below the sulfur layer; The thickness of the sulfur layer is 50 - 100 mm; The volume ratio of the first reactor zone to the second reactor zone is 2 - 10:1; In the sludge mixing zone, the bluestone layer and the pyrite layer provide substrates required by autotrophic denitrifying microorganisms, gradually stimulating the activity of autotrophic microorganisms. Based on traditional denitrification, the proportion of autotrophic denitrifying microorganisms is increased, and through gradual domestication, a microbial community dominated by autotrophic denitrification is formed; The bluestone layer provides inorganic carbon source and calcium ions, providing substrates for the removal of phosphate radicals. The pyrite provides iron ions with different valence states and sulfur ions with low valence states, providing substrates for the removal of nitrate radicals and total phosphorus. Under the action of the formed microbial community dominated by autotrophic denitrification, phosphorus and nitrogen removal are achieved; The wastewater after phosphorus and nitrogen removal flows through the sulfur layer for further purification and then is discharged; The effluent from the first reactor zone meets the requirements of total nitrogen ≤ 15 mg / L and total phosphorus ≤ 0.5 mg / L. Further, as a guarantee section, the wastewater flows through the second reactor zone by gravity.

2. The wastewater treatment device for enhanced biological nitrogen and phosphorus removal according to claim 1, characterized in that: Maintenance openings and observation openings are provided on the side walls of the corresponding housings of the first reactor zone and the second reactor zone.

3. The wastewater treatment device for enhanced biological nitrogen and phosphorus removal according to claim 2, characterized in that: Feeding and maintenance openings are provided at the tops of the corresponding housings of the first reactor zone and the second reactor zone.

4. A wastewater treatment method for enhanced biological nitrogen and phosphorus removal, characterized in that: It includes the following steps: The wastewater to be treated flows through the cobblestone support layer, the bluestone layer, and the pyrite layer from bottom to top in sequence. The bluestone layer provides inorganic carbon source and calcium ions, providing substrates for the removal of phosphate radicals. The pyrite provides iron ions with different valence states and sulfur ions with low valence states, providing substrates for the removal of nitrate radicals and total phosphorus. Under the action of the formed microbial community dominated by autotrophic denitrification, phosphorus and nitrogen removal are achieved; The wastewater after phosphorus and nitrogen removal flows through the sulfur layer for further purification and then is discharged.

5. The wastewater treatment method for enhanced biological nitrogen and phosphorus removal according to claim 4, characterized in that: The residence time of the wastewater to be treated in the first reactor zone is 2 - 4 h, and the residence time in the second reactor zone is 0.2 - 0.5 h.

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