An efficient nitrogen and phosphorus removal reactor and treatment method

Abstract

The present invention relates to the technical field of water treatment, and particularly to a high-efficiency nitrogen and phosphorus removal reactor and a treatment method. 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, has low operating costs and less investment. The results of the examples show that by using the reactor provided by the present invention, the removal rate of total phosphorus in wastewater is more than 70%, and at the same time, a part of ammonia nitrogen can be removed.

Description

Technical Field

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

[0002] Starch wastewater mainly contains pollutants such as starch, sugars, and proteins. The wastewater contains a high concentration of COD (between 3000 and 20000 mg / L), and also contains a high concentration of ammonia nitrogen and phosphorus. If this kind of wastewater is directly discharged without treatment, it will cause large-scale environmental pollution. With the increasingly strict 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 treatment plants.

[0003] At present, ammonia nitrogen and phosphorus in wastewater can generally be treated by chemical treatment and biological treatment. Biological treatment mainly treats through the action of nitrifying and denitrifying bacteria and polyphosphate-accumulating bacteria. To achieve a certain removal efficiency, a large pool volume is required for the removal of total nitrogen and total phosphorus. In particular, it is difficult to directly meet the national discharge standards for total phosphorus through biological treatment. Chemical methods mainly use ammonia nitrogen stripping method and phosphorus removal agents, with relatively high operating costs. For wastewater with high ammonia nitrogen and high phosphorus, it needs to be removed through two process sections, and the process is cumbersome. In order to meet the discharge standards for total nitrogen and total phosphorus, a large amount 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 single 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 a treatment method. The present invention can achieve the efficient removal of nitrogen and phosphorus in wastewater with only one process section, which is convenient and practical, has low operating costs, and requires less investment.

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

[0006] The present invention provides a high-efficiency nitrogen and phosphorus removal reactor, including a reaction zone Ⅰ, a forming zone Ⅱ, and a finished product zone Ⅲ that 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+ inlet pipe 3, and a number of baffle plates 7 that are inclined downward at 40 - 50°;

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

[0009] A flow guiding wall 11 is provided in the forming zone Ⅱ;

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

[0011] The forming zone II communicates with the finished product zone III through an upwardly inclined diversion seam formed by the diversion plates 12;

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

[0013] Preferably, a reflux system 14 is further included, and the reflux system 14 is used to reflux the muddy water mixture in the finished product zone III to the forming zone II.

[0014] Preferably, the reflux system 14 is provided with an upper outlet and a lower outlet, 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 baffle plates 7 form a reaction zone flow channel 16, and the distance between each baffle plate 7 satisfies that the flow velocity of the mixed wastewater in the reaction zone flow channel 16 is 0.1 - 0.3 m / s.

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

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

[0018] Preferably, the diversion plates 12 have a diversion angle of 40 - 50° with the vertical direction.

[0019] The present invention provides a method for treating nitrogen and phosphorus wastewater, which is treated by using the high-efficiency nitrogen and phosphorus removal reactor described in the above solution, and includes the following steps:

[0020] Turn on the first aeration and agitation device 8 at the bottom of the reaction zone I, and introduce nitrogen and phosphorus wastewater from the wastewater inlet pipe 1, alkali solution from the alkali solution inlet pipe 2, and Mg 2+ solution from the Mg 2+ inlet pipe 3 into the reaction zone I simultaneously. The formed mixed wastewater flows obliquely downward through the baffle plates 7 to the bottom of the reaction zone I, enters the forming zone II through the water passing hole 15 at the lower end of the partition plate 10, and turn on the second aeration and agitation device 9. The mixed wastewater undergoes a forming reaction in the forming zone II to form a muddy water mixture; the muddy water mixture enters the finished product zone III through the diversion seam formed by the diversion plates 12, and solid-liquid separation occurs in the finished product zone III. The supernatant is discharged externally through the water outlet pipe 5, and the sludge particles are discharged through the sludge discharge pipe 6.

[0021] Preferably, the dosage of the alkali solution satisfies that the pH value of the mixed wastewater is 8 - 9.5; the Mg 2+ in the solutionMg2+ The molar ratio of N to P in the nitrogen and phosphorus wastewater is 1 to 1.6:1.

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

[0023] The present invention provides an efficient nitrogen and phosphorus removal reactor, including a sequentially connected reaction zone I, forming zone II, and finished product zone III; the reaction zone I is provided with a wastewater inlet pipe 1, an alkali solution inlet pipe 2, a Mg 2+ inlet pipe 3, and several baffle plates 7 inclined downward at 40 to 50°; the reaction zone I is separated from the forming zone II by a partition plate 10, and a water passing hole 15 is left at the lower end of the partition plate 10 for connecting the reaction zone I and the forming zone II; a diversion 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 to the finished product zone III through an upwardly inclined diversion seam formed by diversion plates 12; the finished product zone III is provided with an outlet pipe 5 and a sludge discharge pipe 6.

[0024] In the present invention, baffle plates inclined downward at 40 to 50° are provided in the reaction zone I, and at the same time, a first aeration and stirring device 8 with turbulent flow at the lower end is provided to ensure the strong convective stirring effect of air flow stirring and liquid reverse flow, and a rapid reaction of additives (referring to the added Mg 2+ ) is carried out in the reaction zone I and enters the forming zone II through the water passing hole 15 at the lower end of the partition plate 10; a diversion wall 11 is provided in the forming zone II to change the flow field of the wastewater, ensure that there is enough time for ammonia nitrogen and total phosphorus in the wastewater to form precipitated particles, and improve the reaction effect of the wastewater; in addition, a second aeration and stirring device 9 is provided in the forming zone II to ensure the mixing effect in the forming zone, enhance the collision and forming of particles in the fully mixed state, and at the same time provide a certain shearing force to ensure that the sludge product has sufficient strength; the mixed wastewater in the forming zone II enters the finished product zone III through the diversion seam formed by the diversion plates 12, and solid-liquid separation is completed in the finished product zone III. Through the above detailed settings of the reaction zone and the forming zone, the present invention can efficiently remove nitrogen and phosphorus.

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

[0026] Furthermore, by setting up the reflux system 14, the present invention can drive the mud-water mixture in the finished product area to reflux by the aeration power in the front section without relying on a reflux pump. After refluxing to the forming area II, further reaction can be carried out to further strengthen the strength of the precipitate and improve the utilization efficiency of the Mg source at the same time.

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

[0028] Figure 1 is a plan view of the high-efficiency nitrogen and phosphorus removal reactor;

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

[0030] Figures 1 - 2 In the figure: 1 - waste water inlet pipe, 2 - alkali solution inlet pipe, 3 - Mg 2+ inlet pipe, 4 - inlet air pipe, 5 - outlet water pipe, 6 - sludge discharge pipe, 7 - baffle plate, 8 - first aeration and stirring device, 9 - second aeration and stirring device, 10 - partition plate, 11 - diversion wall, 12 - deflector, 13 - water outlet tank, 14 - reflux system, 15 - water passing hole, 16 - reaction zone flow channel, 17 - liquid level line. DETAILED DESCRIPTION OF THE EMBODIMENTS

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

[0032] The reaction zone I is provided with a waste water inlet pipe 1, an alkali solution inlet pipe 2, a Mg 2+ inlet pipe 3 and a number of baffle plates 7 that slope downward at 40-50°;

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

[0034] The forming zone II is provided with a diversion wall 11;

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

[0036] The forming zone II is communicated with the finished product zone III through an upwardly inclined diversion seam formed by a deflector 12;

[0037] The finished product zone III is provided with an outlet water pipe 5 and a sludge discharge pipe 6.

[0038] Next, in conjunction with Figure 1 and Figure 2Describe the high-efficiency nitrogen and phosphorus removal reactor provided by the present invention.

[0039] As shown in Figure 1 and Figure 2 , the high-efficiency nitrogen and phosphorus removal reactor provided by the present invention includes reaction zone I. In the present invention, the reaction zone I is used for the rapid reaction of nitrogen and phosphorus wastewater to generate precipitates with fine particles, and at the same time, 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+ inlet pipe 3 and a number of baffle plates 7 inclined downward at 40-50°.

[0041] In an embodiment of the present invention, the wastewater inlet pipe 1, the alkali solution inlet pipe 2 and the Mg 2+ inlet pipe 3 are 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+ inlet pipe 3 are at the same horizontal height and higher than the baffle plate 7.

[0042] In the present invention, the included angle between the baffle plate 7 and the side wall of the reaction zone I is 40-50°, preferably 45° (as shown in Figure 2 ). The present invention has no special requirements for the size and spacing of the baffle plate 7. The gaps between the baffle plates 7 form a reaction zone flow channel 16, and the spacing between the baffle plates 7 only needs to satisfy that the flow velocity of the mixed wastewater in the reaction zone flow channel 16 is 0.1-0.3 m / s.

[0043] The present invention has no special requirements for the size of the reaction zone I, and it only needs to satisfy that the residence time of the nitrogen and phosphorus wastewater in the reaction zone I is 5-15 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 an 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 provides a baffle plate 7 inclined downward at 40-50° with the vertical direction in the reaction zone I, and at the same time, a first aeration and stirring device 8 is provided at the bottom end to ensure the strong convective stirring effect of air flow stirring and liquid reverse flow, thereby enhancing the reaction effect of nitrogen and phosphorus in the wastewater with the additive (referring to Mg 2+ ), and improving the nitrogen and phosphorus removal efficiency.

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

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

[0049] The present invention has no special requirements for the size of the water passing hole 15, and it is only necessary to ensure that the particulate matter formed in the reaction zone I can be normally transported to the forming zone II. As an embodiment of the present invention, the flow velocity of the water passing hole is 0.3 m / s.

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

[0051] In the present invention, the setting of the guiding wall 11 can change the wastewater flow field, ensure that there is enough time for ammonia nitrogen and total phosphorus in the wastewater to form precipitated particulate matter, and improve the reaction effect of nitrogen and phosphorus wastewater.

[0052] In the present invention, the number of the guiding walls 11 is at least 1; when the number is 1, it can change the flow field at the lowest cost and increase the turbulent mixing and stirring 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 shares an air inlet pipe 4 with the first aeration and stirring device 8.

[0054] The present invention ensures the mixing effect in the forming zone by setting the second aeration and stirring device 9. In the fully mixed state, it enhances the collision and forming of particles, and at the same time provides a certain shearing force to ensure that the sludge product has sufficient strength.

[0055] The high - efficiency nitrogen and phosphorus removal reactor provided by the present invention includes a finished product zone III; the forming zone II is communicated with the finished product zone III through an obliquely upward guiding seam formed by guiding plates 12. In the present invention, the guiding seam is located at a height position above 1 / 2 of the forming zone II.

[0056] In an embodiment of the present invention, the guiding plates 12 have a guiding angle of 40 - 50°, and more preferably, a guiding angle of 45°. The present invention sets the guiding plates 12 to have a guiding angle of 40 - 50° to ensure that after the mud - water mixture enters the finished product zone III, it will not affect the precipitation effect of the finished product zone III.

[0057] As an embodiment of the present invention, the included angle between the partition plate separating the forming zone II and the finished product zone III and the side wall of the finished product zone III at the lower end of the guiding seam is 45°. By setting it to 45°, the present invention is beneficial to improving the mud - water separation effect in the finished product zone III.

[0058] The present invention has no special requirements for the size of the finished product area III, and it is only necessary to ensure that the upward flow velocity in the finished product area III is 0.6 - 0.8 m / h.

[0059] In the present invention, the finished product area III is provided with a water outlet pipe 5 and a sludge discharge pipe 6; the water outlet pipe 5 is located at the upper part of the finished product area III, and the sludge 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 further includes a reflux system 14, and the reflux system 14 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 (i.e., the front end of the diversion wall 11).

[0062] In the present invention, the reflux system 14 is provided with an upper outlet and a lower outlet. 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. In the present invention, when the density of the refluxed mud - water mixture is small, it will flow out from the upper outlet, and when the density of the mud - water mixture is large, it will flow out from the lower outlet. The present invention does not set a reflux pump, and only relies on the aeration power at the front end to drive the reflux of the mud - water mixture. After refluxing to the forming area II for further reaction, it can 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 is treated by using the above - mentioned high - efficiency nitrogen and phosphorus removal reactor, and includes the following steps:

[0064] Turn on the first aeration and stirring device 8 at the bottom of the reaction area I, and simultaneously introduce the nitrogen and phosphorus wastewater from the wastewater inlet pipe 1, the lye from the lye inlet pipe 2, and the Mg 2+ solution from the Mg 2+ inlet pipe 3 into the reaction area I. The formed mixed wastewater flows obliquely downward through the baffle 7 to the bottom of the reaction area I, and enters the forming area II through the water - passing hole 15 at the lower end of the partition 10. Turn on the second aeration and stirring device 9, and the mixed wastewater undergoes a forming reaction in the forming area II to form a mud - water mixture; the mud - water mixture enters the finished product area III through the diversion seams formed by the diversion plates 12. In the finished product area III, mud - water separation occurs, the supernatant is discharged from the water outlet pipe 5, and the sludge particles are discharged from the sludge discharge pipe 6.

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

[0066] The present invention has no special requirements for the lye, and any lye well-known in the art can be used. For example, it can be a sodium hydroxide solution or a potassium hydroxide solution. To reduce costs, a 27.5 wt% commercial lye is preferably used. In the present invention, the dosage of the lye preferably satisfies that the pH value of the mixed wastewater is 8 - 9.5. In specific embodiments, the pH value of the mixed wastewater can be 8, 8.5, 8.7, 9, or 9.5. By adjusting the pH value of the mixed wastewater within the above range, the present invention aims to provide an alkaline environment and provide the most suitable pH value for the denitrification and phosphorus removal reactions according to different types and components of the wastewater.

[0067] The present invention does not make special limitations on the specific type of the Mg 2+ -containing solution, and any Mg 2+ -containing solution can be used. For example, it can be an aqueous solution of magnesium salts such as MgCl 2 . To reduce costs, the present invention preferably uses an inexpensive MgO solution. Due to the low solubility of MgO, in order to make up for this characteristic, the present invention sets up a reflux system, which improves the quality of the finished sludge and the utilization efficiency of MgO.

[0068] In the present invention, the molar ratio of Mg 2+ in the Mg 2+ -containing solution to P in the nitrogen and phosphorus wastewater is preferably 1 - 1.6:1. In specific embodiments, it 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 and stirring device 8 is preferably 0.5 - 5.0 m 3 / (m 2 ·h). In specific embodiments, 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. In specific embodiments, 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 reaction zone I is preferably 5 - 15 min. In specific embodiments, it can be 5 min, 7 min, 10 min, or 15 min.

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

[0073] Mg 2+ +NH 4 ++PO 4 3- +6H 2 O → MgNH 4 PO 4 ·6H 2 O↓, generating granular precipitation while fine particles aggregate into larger particles.

[0074] The first aeration and agitation device 8 and the baffle 7 are simultaneously arranged in the reaction zone. The aeration device forms bubble agitation and turbulent flow moving upward, and the mixed wastewater flows countercurrently downward. Several turbulent zones will be formed at the baffle 7, enhancing the effect of mass transfer and agitation.

[0075] When the mixed wastewater enters the forming zone II, the particles therein will further aggregate to form precipitated particulate matter. The size of the particulate matter is preferably 0.1 - 0.3 mm and precipitates out from the wastewater.

[0076] In the present invention, the aeration volume of the second aeration and agitation device 9 is preferably 0.5 - 5.0 m 3 / (m 2 ·h), and in specific embodiments, 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 - 2.5 h, and in specific embodiments, it can be 1.5 h, 2 h or 2.5 h.

[0078] By arranging the diversion wall 11 in the forming zone II in the present invention, the flow field of the wastewater can be changed, ensuring that there is sufficient time for ammonia nitrogen and total phosphorus in the wastewater to form precipitated particulate matter and improving the reaction effect of the wastewater; in addition, the second aeration and agitation device 9 is arranged in the forming zone II to ensure the mixing effect in the forming zone. In the fully mixed state, the collision and forming of particles are enhanced, and at the same time, a certain shear force is provided to ensure that the sludge product has sufficient strength.

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

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

[0081] When the high-efficiency nitrogen and phosphorus removal reactor is equipped with a reflux system, the present invention preferably further includes refluxing the muddy water mixture in the finished product area III to the forming area II. By refluxing the muddy water mixture in the finished product area III to the forming area II, the present invention can further strengthen the strength of the formed sludge particles and improve the utilization rate of MgO.

[0082] The following is a detailed description of the high-efficiency nitrogen and phosphorus removal reactor and treatment method provided by the present invention in conjunction with embodiments, but they cannot be understood as limiting the protection scope of the present invention.

[0083] Example 1

[0084] For a certain corn starch production and processing wastewater, the wastewater volume is 1200 m 3 / d. After the wastewater is pretreated and anaerobically treated in the sewage treatment station, the wastewater contains 800 mg / L of COD, 400 mg / L of total nitrogen, and 120 mg / L of total phosphorus. A high-efficiency nitrogen and phosphorus removal reactor is set up, the baffle is inclined downward at 45°, the opening width of a section of the diversion wall from the reactor side wall is 260 mm, the pH of the wastewater during operation is adjusted with alkali liquor to 8.7, and a certain amount of dissolved MgO solution is added. The molar ratio of Mg 2+ to P in the nitrogen and phosphorus wastewater is 1.3:1, the flow velocity in the reaction zone flow channel is 0.25 m / s, the flow velocity of the water passing hole is 0.3 m / s, the aeration volume of the aeration and stirring device in the reaction zone is 1.0 m 3 / (m 2 ·h), the aeration volume of the aeration and stirring device in the forming area is 1.2 m 3 / (m 2 ·h). The wastewater passes through the reaction zone, the forming area and the finished product area in sequence. The residence time in the reaction zone is 15 min, the residence time in the forming area is 2 h, 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 a slow-release fertilizer. The final total phosphorus removal rate of the effluent is 71%, and the total nitrogen removal efficiency is 12.5%. At the same time, it provides a certain alkalinity for denitrification in the subsequent treatment process and reduces the removal burden of total phosphorus in the subsequent treatment.

[0085] The original total phosphorus of the wastewater reached the agreed discharge standard of 1 mg / L, and the dosing cost of the phosphorus remover per cubic meter of water was 3.0 yuan. After setting up the high-efficiency nitrogen and phosphorus removal reactor, the phosphorus removal dosing cost was 0.5 yuan per ton of water, while the operation cost of adding alkali and magnesium salt in the high-efficiency nitrogen and phosphorus removal reactor was 0.8 yuan per cubic meter of water, which reduced the chemical agent operation cost for the enterprise, reduced the labor cost, and at the same time, the sludge rich in nitrogen and phosphorus produced can be used as a raw material for slow-release fertilizer.

[0086] Example 2

[0087] The wastewater from an enzyme preparation workshop uses starch as raw material to produce various enzyme preparations. During the production process, various nutrient elements are added. The wastewater volume is 200 m 3 / d. The COD in the wastewater is 10,000 mg / L, the total nitrogen is 200 mg / L, and the total phosphorus is 120 mg / L. After pretreatment and anaerobic treatment in the sewage treatment station, the wastewater enters a high-efficiency nitrogen and phosphorus removal reactor. The baffle is inclined downward at 45°. The opening width of one end of the diversion wall from the side wall of the reactor is 150 mm. The pH of the wastewater during operation is adjusted to 8.5 by adding alkali solution, and a certain amount of dissolved MgO solution is added at the same time. The molar ratio of Mg 2+ to P in the nitrogen and phosphorus wastewater is 1.3:1. The flow velocity in the reaction zone channel is 0.3 m / s, and the flow velocity in the water passing hole is 0.3 m / s. The aeration volume of the aeration and agitation device in the reaction zone is 1.0 m 3 / (m 2 ·h), and the aeration volume of the aeration and agitation device in the forming zone is 1.5 m 3 / (m 2 ·h). The wastewater passes through the reaction zone, the forming zone, and the finished product zone in sequence. The residence time in the reaction zone is 10 min, and the residence time in the forming zone is 2.5 h. The total phosphorus in the effluent is 40 mg / L, the total nitrogen is 140 mg / 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 nitrogen and phosphorus removal is greatly reduced, the overall operation cost of the sewage treatment station is reduced a lot, and the operation is stable.

[0088] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope 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 an upwardly inclined 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); The high-efficiency nitrogen and phosphorus removal reactor further comprises a reflux system (14), wherein the reflux system (14) is used to reflux the mud-water mixture in the finished product zone (III) to the forming zone (II); 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).

2. 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.

3. The high-efficiency nitrogen and phosphorus removal reactor according to claim 1, 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).

4. The high-efficiency nitrogen and phosphorus removal reactor according to claim 1, 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.

5. The high-efficiency nitrogen and phosphorus removal reactor according to claim 1, characterized in that: The guide plate (12) forms a guide angle of 40 to 50 degrees with the vertical direction.

6. A method for treating nitrogen and phosphorus wastewater, characterized in that: The process of using the high-efficiency nitrogen and phosphorus removal reactor according to any one of claims 1 to 5 comprises 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).

7. The processing method according to claim 6, 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.

8. The processing method according to claim 6 or 7, 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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