A self-circulating diversion device and method suitable for treating high and low carbon-nitrogen ratio sewage

Abstract

The self-circulating diversion device of the present invention is suitable for treating high and low carbon-nitrogen ratio sewage, comprising a first water inlet pipe, an aeration column, a denitrification column, an aeration plate and a water outlet pipe, with a lower anoxic zone and an upper aerobic zone formed below and above the aeration plate; the device is characterized in that: a diversion column is provided between the aeration column and the denitrification column, sludge circulates between the aeration column and the diversion column to form a small circulation reflux; sewage circulates between the aeration column, the diversion column and the denitrification column to form a large circulation reflux. The method for treating sewage with a high carbon-nitrogen ratio comprises: a). water inlet and denitrification reaction; b). aeration and self-circulation; c). aerobic reaction; d). diversion effect; e). short-range denitrification coupled anaerobic ammonia oxidation reaction; f). sewage reflux and discharge. The self-circulating diversion device and method of the present invention can realize the treatment of sewage with a high carbon-nitrogen ratio or a low carbon-nitrogen ratio, and can realize the self-circulation flow of sewage without an external power source, thereby reducing energy consumption in the sewage treatment process.

Description

Technical Field

[0001] The present invention relates to a sewage treatment device and method, and more particularly to a self-circulating diversion device and method suitable for treating high and low carbon-nitrogen ratio sewage. Background Art

[0002] Currently, the mainstream wastewater treatment technology is the traditional activated sludge process, which removes biodegradable organic matter while also removing some phosphorus and nitrogen. The presence of large amounts of these pollutants in wastewater can lead to eutrophication, impacting the growth of fish and other aquatic life.

[0003] Traditional processes for treating organic and nitrogen-containing wastewater include AO and AAO. However, these methods require a very high C / N ratio, consume large amounts of energy, produce large amounts of residual sludge, and are complex processes. Furthermore, these methods cannot achieve high sludge concentrations. Furthermore, the nitrification reaction in traditional biological methods requires a supplemental carbon source when the C / N ratio in the wastewater is low. These processes have relatively strict temperature requirements, are inefficient at low temperatures, require large floor space, and require a large amount of oxygen.

[0004] Anaerobic ammonium oxidation (ANAMMOX) is currently being widely researched as an autotrophic denitrification technology. Anaerobic ammonium oxidation (ANAMMOX) is an autotrophic biological denitrification process that uses ammonia nitrogen as an electron donor and nitrite nitrogen as an electron acceptor, converting both nitrogen species into nitrogen gas and a portion of nitrate nitrogen. This process can partially remove nitrogen from wastewater without the need for organic matter.

[0005] This article aims to invent a process equipment that can quickly gather sludge with good sedimentation performance and prevent the sludge from being lost, separate and gather the sludge in the aeration column and the denitrification column through the diversion effect, and combine short-range denitrification anaerobic ammonia oxidation and granular sludge to achieve nitrogen removal; through the aeration effect of the aeration column, the sewage can circulate more than ten times in the system without adding external power, so that the sewage meets the discharge standards. Summary of the Invention

[0006] In order to overcome the shortcomings of the above technical problems, the present invention provides a self-circulating diversion device and method suitable for treating high and low carbon-nitrogen ratio sewage.

[0007] The self-circulating diversion device of the present invention is suitable for treating high and low carbon-nitrogen ratio sewage, comprising a first water inlet pipe, an aeration column, a denitrification column, an aeration plate and a water outlet pipe. The first water inlet pipe is connected to the bottom of the aeration column and is used to pass the high carbon-nitrogen ratio sewage to be treated into the aeration column. The aeration plate is arranged at the middle and lower part of the aeration column. The internal cavities of the denitrification column below and above the aeration plate form a lower anoxic zone and an upper aerobic zone respectively; the upper end of the denitrification column is connected to the bottom of the aeration column via a third connecting pipe, and the water outlet pipe is connected to the upper end of the denitrification column. , the denitrification column and the lower anoxic zone of the aeration column are inoculated with granular sludge, and the treated sewage is discharged through the outlet pipe; it is characterized in that: a diverter column is provided between the aeration column and the denitrification column, the bottom of the denitrification column is connected with a second water inlet pipe, the low carbon-nitrogen ratio sewage to be treated is introduced into the denitrification column through the second water inlet pipe, the upper part of the aeration column is connected to the upper part of the diverter column through the first connecting pipe, the top of the diverter column is connected to the bottom of the denitrification column through the second connecting pipe, and the bottom of the diverter column is connected to the bottom of the aeration column through the fourth connecting pipe;

[0008] When treating sewage with a high carbon-nitrogen ratio, the sewage to be treated enters the lower part of the aeration column through the first connecting pipe, and denitrification reaction occurs under the action of microorganisms in the aerobic granular sludge in the lower anoxic zone, removing COD and nitrate nitrogen in the influent and return sewage; the aeration plate aerates and oxygenates the sewage entering the aeration column, and aeration provides a power source for the sewage to circulate in the aeration column, diversion column and denitrification column. During the process of sewage rising in the aerobic zone in the upper part of the aeration column, aerobic reaction occurs, removing COD and ammonia nitrogen in the water; the sewage on the upper part of the aeration column flows into the diversion column through the first connecting pipe, and the granular sludge with good sedimentation performance is aggregated in the diversion column. The sludge that falls to the bottom of the diversion column enters the bottom of the aeration column through the fourth connecting pipe, and the sludge circulates between the aeration column and the diversion column to form a small circulation reflux; the sewage after diversion in the diversion column enters the bottom of the denitrification column through the second connecting pipe. During the process of sewage rising in the denitrification column, under the action of microorganisms in the granular sludge, a short-range denitrification coupled with anaerobic ammonia oxidation reaction occurs to denitrify the sewage; the sewage in the upper part of the denitrification column is returned to the bottom of the aeration column through the third connecting pipe, and the sewage circulates between the aeration column, the diversion column and the denitrification column to form a large circulation reflux; the treated sewage flows out through the outlet pipe;

[0009] When treating low carbon-nitrogen ratio sewage, the sewage to be treated enters the bottom of the denitrification column through the second water inlet pipe, and after being mixed with the sewage entering the denitrification column through the second connecting pipe, short-range denitrification coupled with anaerobic ammonium oxidation reaction occurs under the action of microorganisms in the anaerobic ammonium oxidation granular sludge in the denitrification column. It then enters the aeration column, denitrification reaction occurs below the aeration column, and aerobic reaction occurs as the water flow rises.

[0010] The self-circulating diversion device of the present invention is suitable for treating high and low carbon-nitrogen ratio sewage. A partition partition is fixed in the middle and lower part of the internal cavity of the aeration column. The aeration disk is placed on the partition partition in an upward aeration form. Holes are evenly opened on the partition partition. The lower part and the upper part of the partition partition are respectively defined as a lower anoxic zone and an upper aerobic zone. The sewage in the lower anoxic zone flows into the upper aerobic zone through the holes, and the granular sludge with good sedimentation performance in the upper aerobic zone falls into the lower anoxic zone through the holes.

[0011] The self-circulating diversion device of the present invention is suitable for treating high and low carbon-nitrogen ratio sewage, wherein the aeration plate and the partition partition are located at 1 / 3 of the height of the internal cavity in the aeration column, the height of the water outlet of the diversion column communicating with the second connecting pipe is higher than the height of the water inlet communicating with the first connecting pipe, the water inlet of the first connecting pipe communicating with the aeration column is at 3 / 4 of the height of the aeration column, and the water outlet of the first connecting pipe communicating with the diversion column is at 3 / 4 of the height of the diversion column.

[0012] The self-circulating diversion device of the present invention is suitable for treating high and low carbon-nitrogen ratio sewage. The first connecting pipe and the fourth connecting pipe are both horizontal straight pipes, and the second connecting pipe and the third connecting pipe are both composed of horizontal sections and vertical sections. The connection part between the horizontal section and the vertical section is an arc-shaped transition shape to reduce the head loss during the flow of sewage.

[0013] The self-circulating diversion device of the present invention is suitable for treating high and low carbon-nitrogen ratio sewage. The height-to-diameter ratio of the aeration column, diversion column and denitrification column ranges from 3 to 10, and the ratio of the diameter of the aeration column to the diameter of the diversion column ranges from 4 to 10.

[0014] The self-circulating diversion device suitable for treating high and low carbon-nitrogen ratio sewage of the present invention and the method for treating high carbon-nitrogen ratio sewage are characterized by being achieved by the following steps:

[0015] a) Water inflow and denitrification reaction: The high carbon-nitrogen ratio wastewater to be treated enters the anoxic zone at the bottom of the aeration column through the first water inlet pipe and mixes with the wastewater returning from the third connecting pipe. Under the action of microorganisms in the granular sludge, denitrification reaction occurs to remove COD and nitrate nitrogen in the wastewater;

[0016] b) Aeration and self-circulation: The aeration disk aerates and oxygenates the sewage in the aeration column. Aeration expansion reduces the density of the water-gas mixture, making the water pressure in the aeration column lower than that in the denitrification column at the same height, forcing the sewage in the denitrification column to automatically flow into the aeration column. Aeration causes the sewage level in the aeration column to rise. Due to the liquid level difference, the sewage above the aeration column enters the diverter column through the first connecting pipe. Under the action of the liquid level difference, the sewage in the diverter column enters the denitrification column, realizing that aeration provides a power source for the automatic circulation of sewage between the aeration column, diverter column, and denitrification column.

[0017] c) Aerobic reaction: As the sewage rises in the upper aerobic zone of the aeration column, aerobic reactions occur under the action of sludge microorganisms, removing COD and ammonia nitrogen from the water. As the sewage rises, the sludge is distributed with granular sludge with good settling performance at the bottom and flocculent sludge with good settling performance at the top. Granular sludge with good settling performance also falls through the holes in the partition plate and enters the lower anoxic zone.

[0018] d) Diversion: After the sewage flows out of the aeration column, it enters the diversion column through the first connecting pipe. Sludge with good sedimentation performance sinks and accumulates in the diversion column. The sludge that sinks and accumulates at the bottom of the diversion column then enters the lower anoxic zone of the aeration column through the fourth connecting pipe. The sludge flows between the aeration column and the diversion column to form a small circulation reflux.

[0019] e) Short-cut denitrification coupled with anaerobic ammonium oxidation reaction: The sewage flows from the diversion column through the second connecting pipe to the bottom of the denitrification column. As the sewage rises from bottom to top in the denitrification column, a short-cut denitrification reaction occurs under the action of microorganisms in the anaerobic granular sludge, converting nitrate nitrogen into nitrite nitrogen. Anaerobic ammonium oxidation reaction then occurs under the action of anaerobic ammonium oxidizing bacteria, thereby denitrifying the sewage;

[0020] f). Sewage backflow and discharge: Under the action of pressure difference, the sewage from the denitrification column enters the aeration column through the third connecting column to achieve sewage backflow. The sewage flows between the aeration column, diversion column and denitrification column to form a large circulation backflow; the treated water is discharged through the outlet pipe, and the reflux volume is more than ten times the outlet volume, so that the sewage is circulated and treated more than ten times to ensure that the effluent meets the standards.

[0021] The self-circulating diversion device suitable for treating high and low carbon-nitrogen ratio sewage of the present invention and the method for treating low carbon-nitrogen ratio sewage are characterized by being achieved by the following steps:

[0022] 1) Influent and short-cut denitrification coupled anaerobic ammonium oxidation reaction; low carbon-nitrogen ratio sewage to be treated enters the denitrification column through the second inlet pipe below the denitrification column. As the sewage rises from bottom to top in the denitrification column, short-cut denitrification reaction occurs under the action of microorganisms in anaerobic granular sludge, converting nitrate nitrogen into nitrite nitrogen, removing nitrate nitrogen. Anaerobic ammonium oxidation reaction is carried out under the action of anaerobic ammonium oxidizing bacteria, and the sewage is denitrified;

[0023] 2) Denitrification reaction and aeration: Sewage flows out of the denitrification column and enters the anoxic zone at the bottom of the aeration column through the third connecting pipe. Under the action of granular sludge in the lower anoxic zone, denitrification reaction further occurs, enhancing denitrification. The aeration plate aerates and oxygenates the sewage in the aeration column. Aeration expansion reduces the density of the mixed air and water sewage, making the water pressure in the aeration column lower than that in the denitrification column at the same height, forcing the sewage in the denitrification column to automatically flow into the aeration column. Under the action of the liquid level difference, the sewage above the aeration column flows into the diversion column, and the sewage above the diversion column flows into the denitrification column. Aeration provides the power source for the automatic circulation of sewage throughout the entire reaction.

[0024] 3) Aerobic reaction: As the sewage rises in the upper aerobic zone of the aeration column, aerobic reactions occur under the action of sludge microorganisms, removing COD and ammonia nitrogen from the water. As the sewage rises, the sludge is distributed with granular sludge with good settling performance at the bottom and flocculent sludge with poor settling performance at the top. Granular sludge with good settling performance also falls through the holes in the partition plate into the lower anoxic zone.

[0025] 4) Diversion: After the sewage flows out of the aeration column, it enters the diversion column through the first connecting pipe. Sludge with good sedimentation performance sinks and accumulates in the diversion column. The sludge that sinks and accumulates at the bottom of the diversion column enters the lower anoxic zone of the aeration column through the fourth connecting pipe. The sludge flows between the aeration column and the diversion column to form a small circulation reflux.

[0026] 5) Sewage reflux and discharge: Sewage flows from the diverter column into the denitrification column through the second connecting pipe. Under the action of pressure difference, the sewage from the denitrification column enters the aeration column through the third connecting pipe, realizing sewage reflux. The sewage flows between the aeration column, diverter column and denitrification column to form a large circulation reflux; the treated water is discharged through the outlet pipe, and the water reflux volume is more than ten times the outlet volume, so that the sewage is circulated and treated more than ten times to ensure that the effluent meets the standards.

[0027] The method for treating high and low carbon-nitrogen ratio sewage by the self-circulating diversion device of the present invention is that the number of large circulation refluxes of sewage is less than the number of small circulation refluxes of sludge. When the sludge forms forty or fifty small circulation refluxes in the aeration column and the diversion column, the sewage forms more than ten large circulation refluxes in the aeration column, the diversion column and the denitrification column to ensure that the effluent meets the standards.

[0028] The method for treating high and low carbon-nitrogen ratio sewage using a self-circulating diversion device suitable for treating high and low carbon-nitrogen ratio sewage of the present invention comprises the following steps: in the initial stage of sewage treatment, the upper aerobic zone of the aeration column is started with ordinary flocculent sludge, and the sludge settling performance is poor at the beginning. By controlling the aeration volume in the aeration column to be relatively small, the rising flow rate of sewage in the upper aerobic zone of the aeration column is reduced to prevent sludge loss. During the sewage upward flow, the sludge is gradually granulated under the action of shear force, and the settling performance is improved. At this time, the aeration volume is gradually increased, and the rising flow rate of sewage and the reflux volume are increased.

[0029] The beneficial effects of the present invention are as follows: the self-circulating diversion device and method suitable for treating high and low carbon-nitrogen ratio sewage of the present invention are provided with an aeration column, a diversion column and a denitrification column, the bottoms of the aeration column and the denitrification column are respectively provided with a first outlet pipe and a second outlet pipe for introducing the high and low carbon-nitrogen ratio sewage to be treated, the middle and lower parts of the aeration column are provided with an aeration disk and a partition partition, the partition partition divides the aeration column into a lower anoxic zone and an upper aerobic zone, the upper part of the aeration column is connected to the upper part of the diversion column through a first connecting pipe, the bottom of the diversion column is connected to the bottom of the aeration column through a fourth connecting pipe, the upper end of the diversion column is connected to the bottom of the denitrification column through a second connecting pipe, and the top of the denitrification column is connected to the bottom of the denitrification column through a third connecting pipe, so that the self-circulating diversion device and method suitable for treating high and low carbon-nitrogen ratio sewage of the present invention have the following advantages compared with the prior art:

[0030] (1) It can realize the treatment of high carbon-nitrogen ratio sewage or low carbon-nitrogen ratio sewage; when treating high carbon-nitrogen ratio sewage, the sewage is circulated in the lower anoxic zone, the upper aerobic zone and the denitrification column in sequence to undergo denitrification reaction, aerobic reaction and short-cut denitrification coupled anaerobic ammonium oxidation reaction; when treating low carbon-nitrogen ratio sewage, the sewage is circulated in the denitrification column, the lower anoxic zone and the upper aerobic zone in sequence to undergo short-cut denitrification coupled anaerobic ammonium oxidation reaction, denitrification reaction and aerobic reaction, so that when treating low carbon-nitrogen ratio sewage, no carbon source needs to be added;

[0031] (2) It can realize the small circulation reflux of sludge and the large circulation reflux of sewage, which is conducive to ensuring that the effluent meets the standards; the sludge forms a small circulation reflux between the aeration column and the diversion column, and the sewage forms a large circulation reflux between the aeration column, the diversion column and the denitrification column, so that the small circulation reflux of sludge is 4-5 times the large circulation reflux of sewage, making the sewage treatment effect better and helping to ensure that the treated sewage meets the standards.

[0032] (3) Self-circulation of sewage can be achieved without an external power source; through the aeration of the aeration disk in the aeration column, the aerated water and gas mixed with the sewage make the water pressure in the aeration column lower than the water pressure in the denitrification column at the same height position, and the sewage in the denitrification column flows into the bottom of the aeration column through the third connecting pipe under the action of the pressure difference; aeration causes the liquid level in the aeration column to rise, and under the action of the liquid level difference, the sewage in the aeration column enters the diversion column, and the sewage in the diversion column enters the denitrification column. In this way, without the need for an external power source, the sewage can be circulated among the aeration column, the diversion column and the denitrification column through aeration, thereby reducing the energy consumption in the sewage treatment process. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a schematic diagram of the self-circulating diversion device suitable for treating high and low carbon-nitrogen ratio sewage of the present invention;

[0034] Figure 2This is a front view of the self-circulating diversion device suitable for treating high and low carbon-nitrogen ratio sewage of the present invention;

[0035] Figure 3 A top view of a self-circulating diversion device suitable for treating high and low carbon-nitrogen ratio sewage of the present invention;

[0036] In the figure: 1 first water inlet pipe, 1' second water inlet pipe, 2 water outlet pipe, 3 aeration column, 4 first connecting pipe, 5 diversion column, 6 second connecting pipe, 7 denitrification column, 8 third connecting pipe, 9 fourth connecting pipe, 10 aeration plate, 11 partition plate, 12 hole, 13 sealing cover, 14 lower anoxic zone, 15 upper aerobic zone. DETAILED DESCRIPTION

[0037] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0038] like Figure 1 As shown, a schematic diagram of a self-circulating diversion device suitable for treating high and low carbon-nitrogen ratio sewage of the present invention is given. Figure 2 and Figure 3 The self-circulating diversion device suitable for treating high- and low-carbon-nitrogen ratio wastewater is shown in front and top views. It consists of an aeration column 3, a diversion column 5, a denitrification column 7, a first water inlet pipe 1, a second water inlet pipe 1', a water outlet pipe 2, an aeration plate 10, and a partitioning baffle 11. The aeration column 3, diversion column 5, and denitrification column 7 are all cylindrical with hollow interiors and are arranged vertically. The first water inlet pipe 1 is connected to the bottom of the aeration column 3 and is used to introduce the high-carbon-nitrogen ratio wastewater to be treated. The second water inlet pipe 1' is connected to the bottom of the denitrification column 7 and is used to introduce the low-carbon-nitrogen ratio wastewater to be treated. The partitioning baffle 11 and aeration plate 10 are arranged in the lower middle portion of the interior cavity of the aeration column 3. The aeration plate 10 is placed on the partitioning baffle 11 in an upward-discharging manner. The partitioning baffle 11 divides the interior cavity of the aeration column 3 into a lower anoxic zone 14 and an upper aerobic zone 15.

[0039] The outlet pipe 2 is connected to the upper end of the aeration column 3 and is used to discharge treated sewage. The upper portion of the aeration column 3 is connected to the upper portion of the diverter column 5 via the first connecting pipe 1. The sewage from the upper portion of the aeration column 3 enters the diverter column 5 through the first connecting pipe 1. The bottom of the diverter column 5 is connected to the bottom of the aeration column 3 via the fourth connecting pipe 9. After the sewage in the aeration column 3 enters the diverter column 5, the sludge with good settling properties sinks and accumulates at the bottom of the diverter column 5. It then flows back to the bottom of the aeration column 3 through the fourth connecting pipe 9, achieving a small sludge recirculation between the aeration column 3 and the diverter column 5.

[0040] The upper end of the diverter column 5 is connected to the bottom of the denitrification column 7 via a second connecting pipe 6. The wastewater diverted by the diverter column 5 enters the bottom of the denitrification column 7 through the second connecting pipe 6. A sealing cap 13 is provided at the upper end of the denitrification column 7 to ensure that the denitrification column 7 is in a sealed and anoxic state. The upper end of the denitrification column 7 is connected to the bottom of the aeration column 3 via a third connecting pipe 8, so that the wastewater can flow back to the aeration column 3 after being treated in the denitrification column 7.

[0041] The aeration disk 10 in the aeration column 3 aerates the wastewater in the aeration column 3. This aeration reduces the density of the air-water mixture, causing the water pressure in the denitrification column 7 at a similar height to be lower than that in the aeration column 3. This pressure difference forces the wastewater in the denitrification column 7 to automatically flow into the aeration column 3. Similarly, the level difference causes the wastewater in the denitrification column 7 to flow into the diverter column 5, and the water in the diverter column 5 to flow toward the denitrification column 7, achieving automatic wastewater flow. Therefore, the aeration process not only oxygenates and stirs the wastewater but also provides a source of power for its circulation throughout the entire device. The flow of wastewater between the aeration column 3, diverter column 5, and denitrification column 7 forms a large-scale reflux.

[0042] like Figure 2 As shown in the figure, the left end of the first connecting pipe 4 is connected to the aeration column at a position 1 / 4 of the distance from the upper end, the right end of the first connecting pipe 4 is connected to the diverter column at a position 1 / 4 of the distance from the upper end, and the first connecting pipe 4 is in a horizontal state. The second connecting pipe 6 is composed of a vertical section and a horizontal section. The upper end of the second connecting pipe 6 is connected to the diverter column 5, and the lower end of the second connecting pipe 6 is connected to the denitrification column 7. The water outlet of the diverter column 5, that is, the position where it is connected to the second connecting pipe 6, is located at the top thereof, which is higher than the water inlet of the diverter column 5, that is, the position where it is connected to the first connecting pipe 4. The third connecting pipe 8 is composed of a vertical section and a horizontal section. The parts where the horizontal sections of the second connecting pipe 6 and the third connecting pipe 8 are connected to the vertical sections are both arc-shaped transition shapes, which are used to reduce the head loss during the flow of sewage. Granular sludge is cultured in the lower anoxic zone 14 of the aeration column 3 and the denitrification column 7.

[0043] High-concentration nitrogen-containing wastewater enters the lower anoxic zone 14 of the aeration column 3, where it first undergoes denitrification to remove some COD and nitrate nitrogen in the wastewater in order to reduce the nitrogen concentration; low-concentration nitrogen-containing wastewater enters the denitrification column 7, where it undergoes short-range denitrification coupled with anaerobic ammonium oxidation to remove nitrogen.

[0044] The sewage rises rapidly in aeration column 3, reaching over 20 m / h. The suspended sludge in aeration column 3 is subjected to upward shear forces from the water flow, resulting in granulation. This granulation exhibits a smooth surface and a dense structure, resulting in excellent sedimentation and COD removal capabilities. The sludge is then collected and diverted by diversion column 5 and returned to the anoxic zone 14 below aeration column 3, enriching the granular sludge.

[0045] After diversion, the wastewater contains less sludge and enters denitrification column 7. The ratio of the rising flow rates of denitrification column 7 and diverter column 5 is related to the ratio of column diameters. The rising flow rate in denitrification column 7 is lower, 1 / 5 to 1 / 10 of that in diverter column 5. The rising flow rates of the wastewater in aeration column 3, diverter column 5, and denitrification column 7 are determined by the height and cross-sectional area of ​​each reaction column and the wastewater expansion rate in aeration column 3. The rising flow rate of the wastewater, in turn, determines the wastewater return volume in the reaction columns (i.e., aeration column 3, diverter column 5, and denitrification column 7).

[0046] High-C / N ratio wastewater first enters the lower portion of aeration column 3, where denitrification occurs under the action of granular sludge microorganisms, removing COD and nitrate nitrogen from the wastewater. Aeration tray 10 aerates and oxygenates the wastewater entering aeration column 3. As the wastewater rises in aerobic zone 15 above aeration column 3, aerobic reactions occur under the action of sludge microorganisms, removing COD and ammonia nitrogen from the water. The aerated water is diverted by diverter column 5, causing granular sludge with good settling properties to accumulate and fall within the diverter column 5. The wastewater then enters denitrification column 7. In denitrification column 7, microorganisms in the anaerobic ammonium oxidation granular sludge undergo a short-range denitrification-coupled anaerobic ammonium oxidation reaction. The wastewater in denitrification column 7, under the action of a pressure differential, enters the aeration column, achieving wastewater reflux. The treated wastewater is then discharged through outlet pipe 2. If the influent is low carbon-nitrogen ratio sewage, it will first enter the denitrification column 7, where a short-range nitrification-coupled anaerobic ammonium oxidation reaction will occur to remove COD and nitrate nitrogen in the sewage, and then enter the aeration 3, where the reaction is the same as that of high carbon-nitrogen ratio sewage.

[0047] In the early stage of sewage treatment, the upper aerobic zone 15 of the aeration column 3 is started with ordinary flocculent sludge. At the beginning, the sludge settling performance is poor. Therefore, the aeration volume in the aeration column 3 should be controlled to be relatively small so that the rising flow rate of sewage in the aerobic zone of the aeration column is relatively low to prevent sludge loss. During the upward flow of sewage, the sludge gradually granulates under the action of shear force, etc., and the settling performance is improved. At this time, the aeration volume is gradually increased to increase the rising flow rate of sewage and the reflux volume.

[0048] After treatment in the denitrification column 7, the wastewater flows back through the third connecting pipe 8 to the anoxic zone 14 below the aeration column 3. Most of the wastewater from the aeration column 3 then flows into the diversion column 5, with a small portion discharged through the outlet pipe 2. Because the return flow is more than ten times the discharge flow, the wastewater is recycled more than ten times within the equipment to ensure that the effluent meets discharge standards.

[0049] The method for treating high carbon-nitrogen ratio sewage by the self-circulating diversion device suitable for treating high and low carbon-nitrogen ratio sewage is achieved by the following steps:

[0050] a) Water inflow and denitrification reaction: The high carbon-nitrogen ratio wastewater to be treated enters the anoxic zone at the bottom of the aeration column through the first water inlet pipe and mixes with the wastewater returning from the third connecting pipe. Under the action of microorganisms in the granular sludge, denitrification reaction occurs to remove COD and nitrate nitrogen in the wastewater;

[0051] b) Aeration and self-circulation: The aeration disk aerates and oxygenates the sewage in the aeration column. Aeration expansion reduces the density of the water-gas mixture, making the water pressure in the aeration column lower than that in the denitrification column at the same height, forcing the sewage in the denitrification column to automatically flow into the aeration column. Aeration causes the sewage level in the aeration column to rise. Due to the liquid level difference, the sewage above the aeration column enters the diverter column through the first connecting pipe. Under the action of the liquid level difference, the sewage in the diverter column enters the denitrification column, realizing that aeration provides a power source for the automatic circulation of sewage between the aeration column, diverter column, and denitrification column.

[0052] c) Aerobic reaction: As the sewage rises in the upper aerobic zone of the aeration column, aerobic reactions occur under the action of sludge microorganisms, removing COD and ammonia nitrogen from the water. As the sewage rises, the sludge is distributed with granular sludge with good settling performance at the bottom and flocculent sludge with good settling performance at the top. Granular sludge with good settling performance also falls through the holes in the partition plate and enters the lower anoxic zone.

[0053] d) Diversion: After the sewage flows out of the aeration column, it enters the diversion column through the first connecting pipe. Sludge with good sedimentation performance sinks and accumulates in the diversion column. The sludge that sinks and accumulates at the bottom of the diversion column then enters the lower anoxic zone of the aeration column through the fourth connecting pipe. The sludge flows between the aeration column and the diversion column to form a small circulation reflux.

[0054] e) Short-cut denitrification coupled with anaerobic ammonium oxidation reaction: The sewage flows from the diversion column through the second connecting pipe to the bottom of the denitrification column. As the sewage rises from bottom to top in the denitrification column, a short-cut denitrification reaction occurs under the action of microorganisms in the anaerobic granular sludge, converting nitrate nitrogen into nitrite nitrogen. Anaerobic ammonium oxidation reaction then occurs under the action of anaerobic ammonium oxidizing bacteria, thereby denitrifying the sewage;

[0055] f). Sewage backflow and discharge: Under the action of pressure difference, the sewage from the denitrification column enters the aeration column through the third connecting column to achieve sewage backflow. The sewage flows between the aeration column, diversion column and denitrification column to form a large circulation backflow; the treated water is discharged through the outlet pipe, and the reflux volume is more than ten times the outlet volume, so that the sewage is circulated and treated more than ten times to ensure that the effluent meets the standards.

[0056] The method for treating low carbon-nitrogen ratio sewage by the self-circulating diversion device suitable for treating high and low carbon-nitrogen ratio sewage of the present invention is achieved by the following steps:

[0057] 1) Influent and short-cut denitrification coupled anaerobic ammonium oxidation reaction; low carbon-nitrogen ratio sewage to be treated enters the denitrification column through the second inlet pipe below the denitrification column. As the sewage rises from bottom to top in the denitrification column, short-cut denitrification reaction occurs under the action of microorganisms in anaerobic granular sludge, converting nitrate nitrogen into nitrite nitrogen, removing nitrate nitrogen. Anaerobic ammonium oxidation reaction is carried out under the action of anaerobic ammonium oxidizing bacteria, and the sewage is denitrified;

[0058] 2) Denitrification reaction and aeration: Sewage flows out of the denitrification column and enters the anoxic zone at the bottom of the aeration column through the third connecting pipe. Under the action of granular sludge in the lower anoxic zone, denitrification reaction further occurs, enhancing denitrification. The aeration plate aerates and oxygenates the sewage in the aeration column. Aeration expansion reduces the density of the mixed air and water sewage, making the water pressure in the aeration column lower than that in the denitrification column at the same height, forcing the sewage in the denitrification column to automatically flow into the aeration column. Under the action of the liquid level difference, the sewage above the aeration column flows into the diversion column, and the sewage above the diversion column flows into the denitrification column. Aeration provides the power source for the automatic circulation of sewage throughout the entire reaction.

[0059] 3) Aerobic reaction: As the sewage rises in the upper aerobic zone of the aeration column, aerobic reactions occur under the action of sludge microorganisms, removing COD and ammonia nitrogen from the water. As the sewage rises, the sludge is distributed with granular sludge with good settling performance at the bottom and flocculent sludge with poor settling performance at the top. Granular sludge with good settling performance also falls through the holes in the partition plate into the lower anoxic zone.

[0060] 4) Diversion: After the sewage flows out of the aeration column, it enters the diversion column through the first connecting pipe. Sludge with good sedimentation performance sinks and accumulates in the diversion column. The sludge that sinks and accumulates at the bottom of the diversion column enters the lower anoxic zone of the aeration column through the fourth connecting pipe. The sludge flows between the aeration column and the diversion column to form a small circulation reflux.

[0061] 5) Sewage reflux and discharge: Sewage flows from the diverter column into the denitrification column through the second connecting pipe. Under the action of pressure difference, the sewage from the denitrification column enters the aeration column through the third connecting pipe, realizing sewage reflux. The sewage flows between the aeration column, diverter column and denitrification column to form a large circulation reflux; the treated water is discharged through the outlet pipe, and the water reflux volume is more than ten times the outlet volume, so that the sewage is circulated and treated more than ten times to ensure that the effluent meets the standards.

[0062] Among them, the number of large-scale circulation refluxes of sewage is less than the number of small-scale circulation refluxes of sludge. When the sludge forms forty or fifty small-scale circulation refluxes in the aeration column and diversion column, the sewage forms more than ten large-scale circulation refluxes in the aeration column, diversion column and denitrification column to ensure that the effluent meets the standards.

[0063] As can be seen, the self-circulating diversion device and method of the present invention, suitable for treating high- and low-carbon-nitrogen ratio wastewater, achieves automatic circulation of wastewater without the need for an external circulation pump, reducing energy consumption during the wastewater treatment process. The diversion and sedimentation effect of the diversion column reduces the amount of sludge flowing into the denitrification column, achieving sludge aggregation. By selecting different water inlet locations based on the carbon-nitrogen ratio of the water to be treated, and controlling the aeration and reflux rates, through a small sludge cycle and a large sewage cycle, pollutants are removed more economically and efficiently. After more than ten cycles of treatment, ammonia nitrogen is removed from the wastewater, ensuring that the effluent meets discharge requirements.

Claims

1. A self-circulating diversion device suitable for treating high and low carbon-nitrogen ratio sewage, comprising a first water inlet pipe (1), an aeration column (3), a denitrification column (7), an aeration plate (10) and a water outlet pipe (2), wherein the first water inlet pipe is connected to the bottom of the aeration column and is used to introduce the high carbon-nitrogen ratio sewage to be treated into the aeration column, the aeration plate is arranged at the middle and lower part of the aeration column, and the internal cavities of the denitrification column below and above the aeration plate respectively form a lower anoxic zone (14) and an upper aerobic zone (15); the upper end of the denitrification column is connected to the bottom of the aeration column via a third connecting pipe (8), and the water outlet pipe is connected to the upper end of the denitrification column, granular sludge is inoculated in the denitrification column and the lower anoxic zone of the aeration column, and the treated sewage is discharged through the water outlet pipe; the device is characterized in that: A diverter column (5) is provided between the aeration column and the denitrification column. The bottom of the denitrification column is connected to a second water inlet pipe (1'). The low carbon-nitrogen ratio sewage to be treated is introduced into the denitrification column through the second water inlet pipe. The upper part of the aeration column is connected to the upper part of the diverter column through the first connecting pipe (4). The top of the diverter column is connected to the bottom of the denitrification column through the second connecting pipe (6). The bottom of the diverter column is connected to the bottom of the aeration column through the fourth connecting pipe (9). When treating high carbon-nitrogen ratio sewage, the sewage to be treated enters the lower part of the aeration column through the first connecting pipe. Under the action of microorganisms in the aerobic granular sludge in the lower anoxic zone, a denitrification reaction occurs, removing COD and nitrate nitrogen in the influent and return sewage; the aeration plate aerates and oxygenates the sewage entering the aeration column. Aeration provides a power source for the sewage to circulate in the aeration column, diversion column and denitrification column. During the process of sewage rising in the aerobic zone in the upper part of the aeration column, aerobic reaction occurs, removing COD and ammonia nitrogen in the water; the sewage in the upper part of the aeration column flows into the diversion column through the first connecting pipe, and the granular sludge with good sedimentation performance gathers and falls in the diversion column. The sludge that falls to the bottom of the diversion column enters the bottom of the aeration column through the fourth connecting pipe. The sludge circulates between the aeration column and the diversion column to form a small circulation reflux; The diverted sewage in the diversion column enters the bottom of the denitrification column through the second connecting pipe. As the sewage rises in the denitrification column, microorganisms in the granular sludge cause a short-range denitrification-coupled anaerobic ammonium oxidation reaction, thereby denitrifying the sewage. The sewage in the upper part of the denitrification column flows back to the bottom of the aeration column through the third connecting pipe. The sewage circulates between the aeration column, diversion column and denitrification column to form a large circulation reflux. The treated sewage flows out through the outlet pipe. When treating low carbon-nitrogen ratio sewage, the sewage to be treated enters the bottom of the denitrification column through the second water inlet pipe, and after being mixed with the sewage entering the denitrification column through the second connecting pipe, short-range denitrification coupled with anaerobic ammonium oxidation reaction occurs under the action of microorganisms in the anaerobic ammonium oxidation granular sludge in the denitrification column. It then enters the aeration column, denitrification reaction occurs below the aeration column, and aerobic reaction occurs as the water flow rises.

2. The self-circulating diversion device suitable for treating high and low carbon-nitrogen ratio sewage according to claim 1 is characterized in that: A partition plate (11) is fixed to the middle and lower part of the internal cavity of the aeration column (3), and the aeration plate (10) is placed on the partition plate (11) in an upward aeration form. Holes (12) are evenly opened on the partition plate. The lower part and the upper part of the partition plate are respectively a lower anoxic zone (14) and an upper aerobic zone (15); sewage in the lower anoxic zone flows into the upper aerobic zone through the holes, and granular sludge with good sedimentation performance in the upper aerobic zone falls into the lower anoxic zone through the holes.

3. The self-circulating diversion device suitable for treating high and low carbon-nitrogen ratio sewage according to claim 2 is characterized in that: The aeration plate (10) and the partitioning baffle (11) are located at 1 / 3 of the height of the internal cavity in the aeration column (3); the height of the water outlet of the diverter column (5) communicating with the second connecting pipe (6) is higher than the height of the water inlet communicating with the first connecting pipe (4); the water inlet of the first connecting pipe communicating with the aeration column is located at 3 / 4 of the height of the aeration column; and the water outlet of the first connecting pipe communicating with the diverter column is located at 3 / 4 of the height of the diverter column.

4. The self-circulating diversion device suitable for treating high and low carbon-nitrogen ratio sewage according to claim 1 or 2, characterized in that: The first connecting pipe (4) and the fourth connecting pipe (9) are both horizontal straight pipes, and the second connecting pipe (6) and the third connecting pipe (8) are both composed of a horizontal section and a vertical section, and the connection portion between the horizontal section and the vertical section is an arc-shaped transition shape to reduce the head loss during the flow of sewage.

5. The self-circulating diversion device suitable for treating high and low carbon-nitrogen ratio sewage according to claim 1 or 2, characterized in that: The height-to-diameter ratio of the aeration column (3), the diverter column (5) and the denitrification column (7) is in the range of 3 to 10, and the ratio of the diameter of the aeration column to the diameter of the diverter column is in the range of 4 to 10.

6. A method for treating high carbon-nitrogen ratio sewage based on the self-circulating diversion device suitable for treating high and low carbon-nitrogen ratio sewage according to claim 2, characterized in that: This is achieved by following these steps: a) Water inflow and denitrification reaction: The high carbon-nitrogen ratio wastewater to be treated enters the anoxic zone at the bottom of the aeration column through the first water inlet pipe and mixes with the wastewater returning from the third connecting pipe. Under the action of microorganisms in the granular sludge, denitrification reaction occurs to remove COD and nitrate nitrogen in the wastewater; b) Aeration and self-circulation: The aeration disk aerates and oxygenates the sewage in the aeration column. Aeration expansion reduces the density of the water-gas mixture, making the water pressure in the aeration column lower than that in the denitrification column at the same height, forcing the sewage in the denitrification column to automatically flow into the aeration column. Aeration causes the sewage level in the aeration column to rise. Due to the liquid level difference, the sewage above the aeration column enters the diverter column through the first connecting pipe. Under the action of the liquid level difference, the sewage in the diverter column enters the denitrification column, realizing that aeration provides a power source for the automatic circulation of sewage between the aeration column, diverter column, and denitrification column. c) Aerobic reaction: As the sewage rises in the upper aerobic zone of the aeration column, aerobic reactions occur under the action of sludge microorganisms, removing COD and ammonia nitrogen from the water. As the sewage rises, the sludge is distributed with granular sludge with good settling performance at the bottom and flocculent sludge with good settling performance at the top. Granular sludge with good settling performance also falls through the holes in the partition plate and enters the lower anoxic zone. d). Diversion effect; After the sewage flows out of the aeration column, it enters the diversion column through the first connecting pipe. The sludge with good sedimentation performance sinks and gathers in the diversion column. The sludge that sinks and gathers at the bottom of the diversion column then enters the lower anoxic zone of the aeration column through the fourth connecting pipe. The sludge flows between the aeration column and the diversion column to form a small circulation reflux. e) Short-cut denitrification coupled with anaerobic ammonium oxidation reaction: The sewage flows from the diversion column through the second connecting pipe to the bottom of the denitrification column. As the sewage rises from bottom to top in the denitrification column, a short-cut denitrification reaction occurs under the action of microorganisms in the anaerobic granular sludge, converting nitrate nitrogen into nitrite nitrogen. Anaerobic ammonium oxidation reaction then occurs under the action of anaerobic ammonium oxidizing bacteria, thereby denitrifying the sewage; f). Sewage backflow and discharge: Under the action of pressure difference, the sewage from the denitrification column enters the aeration column through the third connecting column to achieve sewage backflow. The sewage flows between the aeration column, diversion column and denitrification column to form a large circulation backflow; the treated water is discharged through the outlet pipe, and the reflux volume is more than ten times the outlet volume, so that the sewage is circulated and treated more than ten times to ensure that the effluent meets the standards.

7. A method for treating low carbon-nitrogen ratio sewage based on the self-circulating diversion device suitable for treating high and low carbon-nitrogen ratio sewage according to claim 2, characterized in that: This is achieved by following these steps: 1) Influent and short-cut denitrification coupled anaerobic ammonium oxidation reaction; low carbon-nitrogen ratio sewage to be treated enters the denitrification column through the second inlet pipe below the denitrification column. As the sewage rises from bottom to top in the denitrification column, short-cut denitrification reaction occurs under the action of microorganisms in anaerobic granular sludge, converting nitrate nitrogen into nitrite nitrogen, removing nitrate nitrogen. Anaerobic ammonium oxidation reaction is carried out under the action of anaerobic ammonium oxidizing bacteria, and the sewage is denitrified; 2) Denitrification reaction and aeration: Sewage flows out of the denitrification column and enters the anoxic zone at the bottom of the aeration column through the third connecting pipe. Under the action of granular sludge in the lower anoxic zone, denitrification reaction further occurs, enhancing denitrification. The aeration plate aerates and oxygenates the sewage in the aeration column. Aeration expansion reduces the density of the mixed air and water sewage, making the water pressure in the aeration column lower than that in the denitrification column at the same height, forcing the sewage in the denitrification column to automatically flow into the aeration column. Under the action of the liquid level difference, the sewage above the aeration column flows into the diversion column, and the sewage above the diversion column flows into the denitrification column. Aeration provides the power source for the automatic circulation of sewage throughout the entire reaction. 3) Aerobic reaction: As the sewage rises in the upper aerobic zone of the aeration column, aerobic reactions occur under the action of sludge microorganisms, removing COD and ammonia nitrogen from the water. As the sewage rises, the sludge is distributed with granular sludge with good settling performance at the bottom and flocculent sludge with poor settling performance at the top. Granular sludge with good settling performance also falls through the holes in the partition plate into the lower anoxic zone. 4). Diversion effect; After the sewage flows out of the aeration column, it enters the diversion column through the first connecting pipe. The sludge with good sedimentation performance sinks and gathers in the diversion column. The sludge that sinks and gathers at the bottom of the diversion column enters the lower anoxic zone of the aeration column through the fourth connecting pipe. The sludge flows between the aeration column and the diversion column to form a small circulation reflux. 5) Sewage reflux and discharge: Sewage flows from the diverter column into the denitrification column through the second connecting pipe. Under the action of pressure difference, the sewage from the denitrification column enters the aeration column through the third connecting pipe, realizing sewage reflux. The sewage flows between the aeration column, diverter column and denitrification column to form a large circulation reflux; the treated water is discharged through the outlet pipe, and the water reflux volume is more than ten times the outlet volume, so that the sewage is circulated and treated more than ten times to ensure that the effluent meets the standards.

8. The method for treating high carbon-nitrogen ratio sewage using a self-circulating diverter device suitable for treating high and low carbon-nitrogen ratio sewage according to claim 6, or the method for treating low carbon-nitrogen ratio sewage using a self-circulating diverter device suitable for treating high and low carbon-nitrogen ratio sewage according to claim 7, characterized in that: The number of large-scale circulation refluxes of sewage is less than the number of small-scale circulation refluxes of sludge. While the sludge forms forty or fifty small-scale circulation refluxes in the aeration column and diversion column, the sewage forms more than ten large-scale circulation refluxes in the aeration column, diversion column and denitrification column to ensure that the effluent meets the standards.

9. The method for treating high carbon-nitrogen ratio sewage using a self-circulating diverter device suitable for treating high and low carbon-nitrogen ratio sewage according to claim 6, or the method for treating low carbon-nitrogen ratio sewage using a self-circulating diverter device suitable for treating high and low carbon-nitrogen ratio sewage according to claim 7, characterized in that: In the early stage of sewage treatment, the upper aerobic zone of the aeration column is started with ordinary flocculent sludge. At the beginning, the sludge settling performance is poor. By controlling the aeration volume in the aeration column to be less, the rising flow rate of sewage in the upper aerobic zone of the aeration column is lowered to prevent sludge loss. During the upward flow of sewage, the sludge gradually granulates under the action of shear force, and the settling performance is improved. At this time, the aeration volume is gradually increased to increase the rising flow rate of sewage and the reflux volume.

Images