Efficient nitrogen and phosphorus removal reactor and treatment method

Abstract

The invention relates to the technical field of water treatment, in particular to an efficient nitrogen and phosphorus removal reactor and a treatment method. According to the method, efficient removal of nitrogen and phosphorus in the wastewater can be realized in the same reactor by only one process section, and the method is convenient, practical, low in operation cost and low in investment. Results of the embodiment show that the reactor provided by the invention has a removal rate of more than 70% on total phosphorus in wastewater, and can remove a part of ammonia nitrogen at the same time.

Description

Technical Field

[0001] The invention relates to the technical field of water treatment, and in particular to a high-efficiency nitrogen and phosphorus removal reactor and a treatment method. Background Art

[0002] With the continuous development of my country's food industry and biochemical industry, especially the increasing number of processing industries using grain and agricultural and sideline products as the main raw materials, the wastewater discharge of such industries has also had an increasing impact on the environment. 3 Starch will produce 10-20m 3 Wastewater, some even more. Starch wastewater mainly contains pollutants such as starch, sugar, protein, etc. The wastewater contains high concentrations of COD (between 3000 and 20000 mg / L), and contains high concentrations of ammonia nitrogen and phosphorus. If this type of wastewater is discharged directly without treatment, it will cause large-scale environmental pollution. With the increasingly stringent control indicators of total nitrogen and total phosphorus parameters in sewage discharge standards, the removal of total nitrogen and total phosphorus has become an important problem in the operation of sewage stations.

[0003] At present, ammonia nitrogen and phosphorus in wastewater can generally be removed by chemical treatment and biological treatment. Biological treatment is mainly carried out through the action of nitrifying and denitrifying bacteria and polyphosphate bacteria. The removal of total nitrogen and total phosphorus requires a large pool capacity to achieve a certain removal efficiency. In particular, it is difficult for total phosphorus to reach the national emission standards directly through biological treatment. The chemical method mainly uses ammonia nitrogen stripping method and phosphorus removal agents, with high operating costs. Wastewater with high ammonia nitrogen and high phosphorus needs to be removed through two process sections, and the process is cumbersome. In order to achieve the emission standards of total nitrogen and total phosphorus, a lot of manpower and material resources need to be invested. Therefore, it is extremely important to find a convenient and practical treatment reactor and treatment method that can directly remove nitrogen and phosphorus from a process section. Summary of the invention

[0004] In view of this, the purpose of the present invention is to provide a high-efficiency nitrogen and phosphorus removal reactor and treatment method. The present invention only requires one process stage to achieve efficient removal of nitrogen and phosphorus in wastewater, which is convenient and practical, and has low operating costs and low investment.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The present invention provides a high-efficiency nitrogen and phosphorus removal reactor, comprising a reaction zone I, a forming zone II and a finished product zone III which are connected in sequence;

[0007] The reaction zone I is provided with a wastewater inlet pipe 1, an alkali solution inlet pipe 2, a Mg 2+ A water inlet pipe 3 and a plurality of baffles 7 with a downward angle of 40 to 50 degrees;

[0008] The reaction zone I and the forming zone II are separated by a partition 10, and a water hole 15 is left at the lower end of the partition 10 for connecting the reaction zone I and the forming zone II;

[0009] A guide wall 11 is provided in the forming area II;

[0010] A first aeration and stirring device 8 is provided at the bottom of the reaction zone I, and a second aeration and stirring device 9 is provided at the bottom of the forming zone II;

[0011] The forming area II is connected to the finished product area III through a guide slot formed by a guide plate 12;

[0012] The finished product area III is provided with a water outlet pipe 5 and a mud discharge pipe 6.

[0013] Preferably, it also includes a reflux system 14, which is used to reflux the mud-water mixture in the finished product area III to the forming area II.

[0014] Preferably, the reflux system 14 is provided with an upper outlet and a lower outlet, wherein the upper outlet is higher than the liquid level line in the forming zone II, and the lower outlet is lower than the inlet height of the reflux system 14 .

[0015] Preferably, the gaps between the baffles 7 form a reaction zone flow channel 16, and the spacing between the baffles 7 satisfies that the flow rate of the mixed wastewater in the reaction zone flow channel 16 is 0.1 to 0.3 m / s.

[0016] Preferably, a water outlet trough 13 is provided in the finished product area III, and the water outlet pipe 5 is arranged on the side wall of the water outlet trough 13 .

[0017] Preferably, an opening is left between one end of the guide wall 11 and the side wall of the forming area II, and the width of the opening is 100 to 500 mm.

[0018] Preferably, the guide plate 12 has a guide angle of 40 to 50 degrees.

[0019] The present invention provides a method for treating nitrogen and phosphorus wastewater, which uses the high-efficiency nitrogen and phosphorus removal reactor described in the above scheme for treatment, and comprises the following steps:

[0020] Open the first aeration stirring device 8 at the bottom of reaction zone I, and draw nitrogen and phosphorus wastewater from wastewater inlet pipe 1, alkali solution from alkali solution inlet pipe 2, and Mg-containing 2+ Solution from Mg 2+The water inlet pipe 3 is simultaneously connected to the reaction zone I, and the formed mixed wastewater flows obliquely downward into the bottom of the reaction zone I through the baffle plate 7, and enters the forming zone II through the water hole 15 at the lower end of the partition plate 10. The second aeration and stirring device 9 is turned on, and the mixed wastewater undergoes a forming reaction in the forming zone II to form a mud-water mixture; the mud-water mixture enters the finished product zone III through the guide gap formed by the guide plate 12, and mud and water separation occurs in the finished product zone III, the supernatant is discharged from the outlet pipe 5, and the sludge particles are discharged from the mud discharge pipe 6.

[0021] Preferably, the amount of the alkali solution is such that the pH value of the mixed wastewater is 8 to 9.5; 2+ Mg in solution 2+ The molar ratio of P to nitrogen and phosphorus wastewater is 1 to 1.6:1.

[0022] Preferably, the residence time of the nitrogen and phosphorus wastewater in the reaction zone I is 5 to 15 minutes, and the residence time in the forming zone II is 1.5 to 2.5 hours.

[0023] The present invention provides a high-efficiency nitrogen and phosphorus removal reactor, comprising a reaction zone I, a forming zone II and a finished product zone III connected in sequence; the reaction zone I is provided with a wastewater inlet pipe 1, an alkali solution inlet pipe 2, a Mg 2+ A water inlet pipe 3 and a plurality of baffles 7 with a downward angle of 40 to 50 degrees; the reaction zone I is separated from the forming zone II by a partition 10, and a water hole 15 is left at the lower end of the partition 10 for connecting the reaction zone I with the forming zone II; a guide wall 11 is provided in the forming zone II; a first aeration and stirring device 8 is provided at the bottom of the reaction zone I, and a second aeration and stirring device 9 is provided at the bottom of the forming zone II; the forming zone II is connected with the finished product zone III through a guide seam formed by a guide plate 12; the finished product zone III is provided with a water outlet pipe 5 and a mud discharge pipe 6.

[0024] The present invention sets a baffle plate with a downward angle of 40-50° in the reaction zone I, and sets a first turbulent aeration stirring device 8 at the lower end to ensure the strong convection stirring effect of air flow stirring and liquid counterflow. 2+ ) reacts quickly, and enters the forming area II through the water hole 15 at the lower end of the partition 10; a guide wall 11 is set in the forming area II to change the flow field of the wastewater, ensure that the ammonia nitrogen and total phosphorus in the wastewater have enough time to form precipitated particles, and improve the reaction effect of the wastewater; in addition, the forming area II is provided with a second aeration stirring device 9 to ensure the mixing effect in the forming area, in the fully mixed state, enhance the collision formation of particles, and provide a certain shear force to ensure that the sludge product has sufficient strength; the mixed wastewater in the forming area II enters the finished product area III through the guide seam formed by the guide plate 12, and the mud and water separation is completed in the finished product area III. The present invention can efficiently remove nitrogen and phosphorus through the above-mentioned detailed settings of the reaction area and the forming area.

[0025] The present invention only needs one process section in the same reactor to achieve efficient removal of nitrogen and phosphorus in wastewater, which is convenient and practical, and has low operating costs and low investment. The results of the embodiment show that the reactor provided by the present invention has a removal rate of more than 70% of total phosphorus in wastewater, and can also remove a part of ammonia nitrogen, with an ammonia nitrogen removal rate of 7-40% (slightly different for different water qualities).

[0026] Furthermore, the present invention provides a reflux system 14, which does not require a reflux pump. The mud-water mixture in the finished product area can be driven to reflux by the aeration power of the front section, and then refluxed to the forming area II for further reaction, thereby further enhancing the strength of the formed precipitate and improving the utilization efficiency of the Mg source.

[0027] In addition, the guide plate 12 has a guide angle of 40 to 50 degrees, which can ensure that the mud-water mixture enters the finished product area III without affecting the sedimentation effect of the finished product area III. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a plan view of a reactor for efficient nitrogen and phosphorus removal;

[0029] Figure 2 is a cross-sectional view of a high-efficiency nitrogen and phosphorus removal reactor;

[0030] Figures 1-2 Middle: 1-wastewater inlet pipe, 2-alkali solution inlet pipe, 3-Mg 2+ Water inlet pipe, 4-air inlet pipe, 5-water outlet pipe, 6-sludge discharge pipe, 7-baffle, 8-first aeration stirring device, 9-second aeration stirring device, 10-partition, 11-guide wall, 12-guide plate, 13-water outlet trough, 14-reflux system, 15-water tunnel, 16-reaction zone flow channel, 17-liquid level line. DETAILED DESCRIPTION

[0031] The present invention provides a high-efficiency nitrogen and phosphorus removal reactor, comprising a reaction zone I, a forming zone II and a finished product zone III which are connected in sequence;

[0032] The reaction zone I is provided with a wastewater inlet pipe 1, an alkali solution inlet pipe 2, a Mg 2+ A water inlet pipe 3 and a plurality of baffles 7 with a downward angle of 40 to 50 degrees;

[0033] The reaction zone I and the forming zone II are separated by a partition 10, and a water hole 15 is left at the lower end of the partition 10 for connecting the reaction zone I and the forming zone II;

[0034] A guide wall 11 is provided in the forming area II;

[0035] A first aeration and stirring device 8 is provided at the bottom of the reaction zone I, and a second aeration and stirring device 9 is provided at the bottom of the forming zone II;

[0036] The forming area II is connected to the finished product area III through a guide slot formed by a guide plate 12;

[0037] The finished product area III is provided with a water outlet pipe 5 and a mud discharge pipe 6.

[0038] Combine the following Figure 1 and Figure 2 The high-efficiency nitrogen and phosphorus removal reactor provided by the present invention is described.

[0039] like Figure 1 and Figure 2 As shown, the high-efficiency nitrogen and phosphorus removal reactor provided by the present invention includes a reaction zone I. In the present invention, the reaction zone I is used to perform a rapid reaction of nitrogen and phosphorus wastewater to generate fine particle precipitation, while some fine particles aggregate into larger particles.

[0040] In the present invention, the reaction zone I is provided with a wastewater inlet pipe 1, an alkali solution inlet pipe 2, a Mg 2+ The water inlet pipe 3 and a plurality of baffles 7 with a downward angle of 40 to 50 degrees.

[0041] In one embodiment of the present invention, the wastewater inlet pipe 1, the alkali solution inlet pipe 2 and the Mg 2+ The water inlet pipe 3 is located on the same side wall of the reaction zone I, and the wastewater inlet pipe 1, the alkali solution inlet pipe 2 and the Mg 2+ The water inlet pipe 3 is at the same horizontal plane height and is higher than the baffle 7 .

[0042] In the present invention, the angle between the baffle plate 7 and the side wall of the reaction zone I is 40-50°, preferably 45° (e.g. Figure 2 The present invention has no special requirements on the size and spacing of the baffles 7. The gaps between the baffles 7 form the reaction zone flow channel 16. The spacing between the baffles 7 can satisfy the flow rate of the mixed wastewater in the reaction zone flow channel 16 to be 0.1 to 0.3 m / s.

[0043] The present invention has no special requirements on the size of the reaction zone I, as long as the residence time of the nitrogen and phosphorus wastewater in the reaction zone I is 5 to 15 minutes.

[0044] In the present invention, a first aeration and stirring device 8 is provided at the bottom of the reaction zone I.

[0045] As an embodiment of the present invention, the first aeration and stirring device 8 is communicated with the air inlet pipe 4 , and gas is provided to the first aeration and stirring device 8 through the air inlet pipe 4 .

[0046] The present invention sets a 40-50° downward baffle 7 in the reaction zone I, and sets a first aeration stirring device 8 at the bottom to ensure the strong convection stirring effect of air flow stirring and liquid counterflow, thereby enhancing the nitrogen and phosphorus in the wastewater and the additive (referring to Mg 2 + ) reaction effect, improving the efficiency of phosphorus and nitrogen removal.

[0047] The high-efficiency nitrogen and phosphorus removal reactor provided by the present invention comprises a forming zone II; the forming zone II is used to give ammonia nitrogen and total phosphorus in wastewater enough time to form precipitated particles.

[0048] In the present invention, the reaction zone I and the forming zone II are separated by a partition 10, and a water hole 15 is left at the lower end of the partition 10 for connecting the reaction zone I and the forming zone II.

[0049] The present invention has no special requirements on the size of the water passage 15, as long as it can ensure that the particles formed in the reaction zone I are normally transported to the forming zone II. As an embodiment of the present invention, the flow rate of the water passage is 0.3 m / s.

[0050] In the present invention, a guide wall 11 is provided in the forming area II; an opening is left between one end of the guide wall 11 and the side wall of the forming area II, and the width of the opening is 100 to 500 mm, specifically 100 mm, 200 mm, 300 mm, 400 mm or 500 mm.

[0051] In the present invention, the setting of the guide wall 11 can change the flow field of the wastewater, ensure that the ammonia nitrogen and total phosphorus in the wastewater have enough time to form precipitated particles, and improve the reaction effect of nitrogen and phosphorus wastewater.

[0052] In the present invention, the number of the guide wall 11 is at least one; when the number is one, the flow field can be changed at a minimum cost to increase the turbulent mixing effect.

[0053] In the present invention, a second aeration and stirring device 9 is provided at the bottom of the forming zone II; the second aeration and stirring device 9 and the first aeration and stirring device 8 share an air inlet pipe 4 .

[0054] The present invention provides a second aeration stirring device 9 to ensure the mixing effect in the forming zone, enhance the collision forming of particles in the fully mixed state, and provide a certain shear force to ensure that the sludge product has sufficient strength.

[0055] The high-efficiency nitrogen and phosphorus removal reactor provided by the present invention comprises a finished product zone III; the forming zone II is connected to the finished product zone III through a guide slot formed by a guide plate 12. In the present invention, the guide slot is located at a height position above 1 / 2 of the forming zone II.

[0056] In one embodiment of the present invention, the guide plate 12 has a guide angle of 40 to 50 degrees, and more preferably a guide angle of 45 degrees. The present invention sets the guide plate 12 to have a guide angle of 40 to 50 degrees, which can ensure that the mud-water mixture will not affect the sedimentation effect of the finished product area III after entering the finished product area III.

[0057] As an embodiment of the present invention, the angle between the partition plate located at the lower end of the guide slot and the side wall of the finished product area III for separating the forming area II and the finished product area III is 45°. The present invention is advantageous in improving the mud-water separation effect in the finished product area III by setting the angle at 45°.

[0058] The present invention has no special requirements on the size of the finished product area III, as long as the rising flow rate in the finished product area III is 0.6 to 0.8 m / h.

[0059] In the present invention, the finished product area III is provided with a water outlet pipe 5 and a mud discharge pipe 6; the water outlet pipe 5 is located at the upper part of the finished product area III, and the mud discharge pipe 6 is located at the lower part of the finished product area III.

[0060] As an embodiment of the present invention, a water outlet trough 13 is further provided in the finished product area III, and the water outlet pipe 5 is arranged on the side wall of the water outlet trough 13 .

[0061] As an embodiment of the present invention, the high-efficiency nitrogen and phosphorus removal reactor provided by the present invention also includes a reflux system 14, which is used to reflux the mud-water mixture in the finished product area III to the forming area II, and more preferably to the front end of the forming area II (that is, the front end of the guide wall 11).

[0062] In the present invention, the reflux system 14 is provided with an upper outlet and a lower outlet, wherein the upper outlet is higher than the liquid level line in the forming zone II, and the lower outlet is lower than the inlet height of the reflux system 14. In the present invention, when the density of the refluxed mud-water mixture is relatively small, it will flow out from the upper outlet, and when the density of the mud-water mixture is relatively large, it will flow out from the lower outlet. The present invention does not provide a reflux pump, and can drive the mud-water mixture to reflux only by relying on the aeration power at the front end, and wait for the reflux to the forming zone II for further reaction, further strengthen the strength of the formed precipitate, and at the same time improve the utilization efficiency of the Mg source.

[0063] The present invention provides a method for treating nitrogen and phosphorus wastewater, which uses the above-mentioned high-efficiency nitrogen and phosphorus removal reactor for treatment, and comprises the following steps:

[0064] Open the first aeration stirring device 8 at the bottom of reaction zone I, and draw nitrogen and phosphorus wastewater from wastewater inlet pipe 1, alkali solution from alkali solution inlet pipe 2, and Mg-containing 2+ Solution from Mg 2+The water inlet pipe 3 is simultaneously connected to the reaction zone I, and the formed mixed wastewater flows obliquely downward into the bottom of the reaction zone I through the baffle plate 7, and enters the forming zone II through the water hole 15 at the lower end of the partition plate 10. The second aeration and stirring device 9 is turned on, and the mixed wastewater undergoes a forming reaction in the forming zone II to form a mud-water mixture; the mud-water mixture enters the finished product zone III through the guide gap formed by the guide plate 12, and mud and water separation occurs in the finished product zone III, the supernatant is discharged from the outlet pipe 5, and the sludge particles are discharged from the mud discharge pipe 6.

[0065] The present invention has no special requirements for the nitrogen-phosphorus wastewater, and any nitrogen-phosphorus wastewater containing ammonia nitrogen and phosphorus can be used. In a specific embodiment, the nitrogen-phosphorus wastewater can be wastewater from a corn starch production and processing plant or wastewater from an enzyme preparation workshop.

[0066] The present invention has no special requirements for the alkali solution, and any alkali solution well known in the art can be used, for example, sodium hydroxide solution or potassium hydroxide solution. In order to reduce costs, 27.5wt% commercial liquid alkali is preferably used. In the present invention, the amount of the alkali solution preferably satisfies the pH value of the mixed wastewater to be 8 to 9.5. In a specific embodiment, the pH value of the mixed wastewater can be 8, 8.5, 8.7, 9 or 9.5. The present invention adjusts the pH value of the mixed wastewater within the above range in order to provide an alkaline environment, and provide the most suitable pH value for the denitrification and dephosphorization reaction according to different types of wastewater and different wastewater components.

[0067] The present invention is to 2+ The specific type of solution is not limited, and any solution containing Mg 2+ Any solution can be used, such as an aqueous solution of magnesium salts such as MgCl2. In order to reduce costs, the present invention preferably uses a low-priced MgO solution. Since MgO has low solubility, in order to compensate for this characteristic, the present invention sets a reflux system to improve the quality of the finished sludge and the utilization efficiency of MgO.

[0068] In the present invention, the Mg-containing 2+ Mg in solution 2+ The molar ratio of P to nitrogen and phosphorus wastewater is preferably 1 to 1.6:1, and in specific embodiments can be 1:1, 1.2:1, 1.3:1, 1.5:1 or 1.6:1.

[0069] In the present invention, the aeration volume of the first aeration stirring device 8 is preferably 0.5 to 5.0 m 3 / (m 2 h), in a specific embodiment, it can be 0.5, 1.0, 2.0, 3.0, 4.0 or 5.0 m 3 / (m 2 h).

[0070] In the present invention, the flow velocity of the mixed wastewater in the reaction zone flow channel 16 formed by the baffle 7 is preferably 0.1-0.3 m / s, and in a specific embodiment, it can be 0.5 m / s, 0.2 m / s or 0.3 m / s.

[0071] In the present invention, the residence time of the ammonia nitrogen wastewater in the reaction zone I is preferably 5 to 15 minutes. In a specific embodiment, it can be 5 minutes, 7 minutes, 10 minutes or 15 minutes.

[0072] The present invention rapidly undergoes the following reactions in the reaction zone I:

[0073] Mg 2+ +NH4 + +PO4 3- +6H2O→MgNH4PO4·6H2O↓, particle precipitation is generated and small particles aggregate into larger particles.

[0074] The first aeration stirring device 8 and the baffle 7 are simultaneously arranged in the reaction zone. The aeration device forms bubbles to stir the turbulent flow upward, and the mixed wastewater flows countercurrently downward. Several turbulent flow zones are formed at the baffle 7, thereby enhancing the mass transfer stirring effect.

[0075] When the mixed wastewater enters the forming zone II, the particles therein will further aggregate to form precipitated particles, the size of which is preferably 0.1 to 0.3 mm, and precipitate out of the wastewater.

[0076] In the present invention, the aeration rate of the second aeration stirring device 9 is preferably 0.5 to 5.0 m 3 / (m 2 h), in a specific embodiment, it can be 0.5, 1.0, 2.0, 3.0, 4.0 or 5.0 m 3 / (m 2 h).

[0077] In the present invention, the residence time of the mixed wastewater in the forming zone II is preferably 1.5 to 2.5 hours, and in a specific embodiment, it can be 1.5 hours, 2 hours or 2.5 hours.

[0078] The present invention can change the flow field of wastewater by setting a guide wall 11 in forming zone II, ensuring that ammonia nitrogen and total phosphorus in the wastewater have enough time to form precipitated particles, thereby improving the reaction effect of the wastewater; in addition, a second aeration stirring device 9 is set in forming zone II to ensure the mixing effect in the forming zone, enhance the collision forming of particles in a fully mixed state, and provide a certain shear force to ensure that the sludge product has sufficient strength.

[0079] After the mud-water mixture formed in the forming area II enters the finished product area III, mud-water separation occurs under the action of its own gravity, wherein the sludge particles are discharged from the reactor from the sludge discharge pipe 6. The discharged sludge particles are 0.2-0.8 mm in size, irregular in shape, and rich in nitrogen and phosphorus. After treatment, they can be further effectively utilized; the supernatant is discharged through the outlet pipe 5.

[0080] In the present invention, when a water outlet trough 13 is provided in the finished product area III, when the liquid level line 17 in the finished product area III reaches the height of the water outlet trough 13 , the liquid will be discharged from the water outlet trough 13 .

[0081] When the high-efficiency nitrogen and phosphorus removal reactor is provided with a reflux system, the present invention preferably further comprises reflux the mud-water mixture in the finished product zone III to the forming zone II. The present invention can further enhance the strength of the formed sludge particles and improve the utilization rate of MgO by reflux the mud-water mixture in the finished product zone III to the forming zone II.

[0082] The highly efficient nitrogen and phosphorus removal reactor and treatment method provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0083] Example 1

[0084] Wastewater from corn starch production and processing, with a wastewater volume of 1200m 3 / d, after the wastewater is pre-treated and anaerobic treated at the sewage station, the wastewater contains 800mg / L COD, 400mg / L total nitrogen, and 120mg / L total phosphorus. A high-efficiency nitrogen and phosphorus removal reactor is set up, with the baffle inclined downward at 45°, and the width of the opening of the guide wall from the reactor side wall is 260mm. The pH of the wastewater is adjusted to 8.7 by adding alkali solution, and a certain amount of dissolved MgO solution is added at the same time. Mg 2+ The molar ratio of P to nitrogen and phosphorus wastewater is 1.3:1, the flow velocity in the reaction zone is 0.25m / s, the flow velocity through the water tunnel is 0.3m / s, and the aeration volume of the aeration stirring device in the reaction zone is 1.0m 3 / (m 2 h), the aeration volume of the aeration stirring device in the forming area is 1.2m 3 / (m 2 h), the wastewater passes through the reaction zone, forming zone and finished product zone in turn. The residence time in the reaction zone is 15 minutes, the residence time in the forming zone is 2 hours, and the total phosphorus in the effluent is 34 mg / L and the total nitrogen is 350 mg / L. Part of the sludge is discharged at regular intervals. After treatment, the sludge rich in ammonia nitrogen and total phosphorus enters agriculture for use as slow-release fertilizer. The final effluent total phosphorus removal rate is 71%, and the total nitrogen removal efficiency is 12.5%. At the same time, a certain alkalinity is provided for the subsequent treatment process of denitrification. The removal burden of total phosphorus in subsequent treatment is reduced.

[0085] The original total phosphorus in the wastewater reached the agreed emission standard of 1 mg / L, and the cost of adding phosphorus removal agents per cubic meter of water was 3.0 yuan. After the installation of a high-efficiency nitrogen-phosphorus removal reactor, the cost of adding phosphorus removal agents was 0.5 yuan per ton of water, and the operating cost of adding alkali and magnesium salts of the high-efficiency nitrogen-phosphorus removal reactor was 0.8 yuan per cubic meter of water, which reduced the operating cost of the agents and labor costs for the company. At the same time, the nitrogen-phosphorus-rich sludge produced can be used as a raw material for slow-release fertilizers.

[0086] Example 2

[0087] Wastewater from an enzyme preparation workshop, which uses starch as raw material to produce various enzyme preparations. Various nutrients are added during the production process. The wastewater volume is 200m 3 / d, COD in wastewater is 10000mg / L, total nitrogen is 200mg / L, and total phosphorus is 120mg / L. After pretreatment and anaerobic treatment in the sewage station, the wastewater enters the high-efficiency nitrogen and phosphorus removal reactor. The baffle is inclined downward at 45°, and the opening width of one end of the guide wall from the reactor side wall is 150mm. The pH of the wastewater is adjusted to 8.5 by adding alkali solution, and a certain amount of dissolved MgO solution is added at the same time. Mg 2+ The molar ratio of P to nitrogen and phosphorus wastewater is 1.3:1, the flow velocity in the reaction zone is 0.3m / s, the flow velocity through the water tunnel is 0.3m / s, and the aeration volume of the aeration stirring device in the reaction zone is 1.0m 3 / (m 2 ·h), the aeration volume of the aeration stirring device in the forming area is 1.5m 3 / (m 2 ·h), the wastewater passes through the reaction zone, forming zone and finished product zone in turn. The residence time in the reaction zone is 10min, and the residence time in the forming zone is 2.5h. The total phosphorus in the effluent is 40mg / L, the total nitrogen is 140mg / L, the removal rate of total phosphorus is 80%, and the removal efficiency of total nitrogen is 30%. At the same time, the load of subsequent biological denitrification and phosphorus removal is greatly reduced, the overall operating cost of the sewage station is reduced a lot, and the operation is stable.

[0088] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A high-efficiency nitrogen and phosphorus removal reactor, characterized in that: It includes a reaction zone (I), a forming zone (II) and a finished product zone (III) which are connected in sequence; The reaction zone (I) is provided with a wastewater inlet pipe (1), an alkali solution inlet pipe (2), a Mg 2+ A water inlet pipe (3) and a plurality of baffles (7) with a downward angle of 40 to 50 degrees; The reaction zone (I) and the forming zone (II) are separated by a partition (10), and a water hole (15) is left at the lower end of the partition (10) for connecting the reaction zone (I) and the forming zone (II); A guide wall (11) is provided in the forming area (II); A first aeration and stirring device (8) is provided at the bottom of the reaction zone (I), and a second aeration and stirring device (9) is provided at the bottom of the forming zone (II); The forming area (II) is connected to the finished product area (III) through a guide slot formed by a guide plate (12); The finished product area (III) is provided with a water outlet pipe (5) and a mud discharge pipe (6).

2. The high-efficiency nitrogen and phosphorus removal reactor according to claim 1, characterized in that: It also includes a return system (14), which is used to return the mud-water mixture in the finished product area (III) to the forming area (II).

3. The high-efficiency nitrogen and phosphorus removal reactor according to claim 2, characterized in that: The reflux system (14) is provided with an upper outlet and a lower outlet, wherein the upper outlet is higher than the liquid level line in the forming area (II), and the lower outlet is lower than the inlet height of the reflux system (14).

4. The high-efficiency nitrogen and phosphorus removal reactor according to claim 1, characterized in that: The gaps between the baffles (7) form a reaction zone flow channel (16), and the spacing between the baffles (7) satisfies that the flow rate of the mixed wastewater in the reaction zone flow channel (16) is 0.1 to 0.3 m / s.

5. The high-efficiency nitrogen and phosphorus removal reactor according to claim 1 or 2, characterized in that: A water outlet trough (13) is provided in the finished product area (III), and the water outlet pipe (5) is arranged on the side wall of the water outlet trough (13).

6. The high-efficiency nitrogen and phosphorus removal reactor according to claim 1, 2 or 3, characterized in that: An opening is left between one end of the guide wall (11) and the side wall of the forming area (II), and the width of the opening is 100 to 500 mm.

7. The high-efficiency nitrogen and phosphorus removal reactor according to claim 1, characterized in that: The guide plate (12) has a guide angle of 40 to 50 degrees.

8. A method for treating nitrogen and phosphorus wastewater, characterized in that: The process is carried out using the high-efficiency nitrogen and phosphorus removal reactor according to any one of claims 1 to 7, comprising the following steps: The first aeration stirring device (8) at the bottom of the reaction zone (I) is turned on to introduce nitrogen and phosphorus wastewater from the wastewater inlet pipe (1), alkali solution from the alkali solution inlet pipe (2), and Mg-containing 2+ Solution from Mg 2+ The water inlet pipe (3) simultaneously flows into the reaction zone (I), and the formed mixed wastewater flows obliquely downward into the bottom of the reaction zone (I) through the baffle plate (7), and enters the forming zone (II) through the water hole (15) at the lower end of the partition plate (10). The second aeration and stirring device (9) is turned on, and the mixed wastewater undergoes a forming reaction in the forming zone (II) to form a mud-water mixture; the mud-water mixture enters the finished product zone (III) through the guide slit formed by the guide plate (12), and mud-water separation occurs in the finished product zone (III), the supernatant is discharged from the water outlet pipe (5), and the sludge particles are discharged from the mud discharge pipe (6).

9. The processing method according to claim 8, characterized in that: The amount of alkali solution used is sufficient to satisfy the pH value of the mixed wastewater of 8 to 9.5; 2+ Mg in solution 2+ The molar ratio of P to nitrogen and phosphorus wastewater is 1 to 1.6:

1.

10. The processing method according to claim 8 or 9, characterized in that: The residence time of the nitrogen and phosphorus wastewater in the reaction zone (I) is 5 to 15 minutes, and the residence time in the forming zone (II) is 1.5 to 2.5 hours.

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