Two-stage PD-HAP coupled Anammox synchronous nitrogen and phosphorus removal device and method

Abstract

The invention relates to a two-stage PD-HAP coupled Anammox synchronous nitrogen and phosphorus removal method in the technical field of sewage biochemical treatment, and aims to solve the problems that phosphorus cannot be removed by a PD / A process, phosphorus resources are difficult to recover and the like, short-cut denitrification and a hydroxyapatite process (PD / HAP) are combined, Anammox is synchronously coupled, the purpose of synchronous nitrogen and phosphorus removal is achieved, and phosphorus recovery can also be taken into consideration. The real-time control device is simple to operate, the reactor can be flexibly regulated and controlled, the reaction condition can be timely optimized, the total nitrogen removal rate is stabilized at 85%, and the phosphorus removal rate reaches 83%.

Description

Technical Field

[0001] The present invention relates to the technical field of sewage biochemical treatment, and in particular to a biochemical treatment device and a biochemical treatment method for simultaneous nitrogen and phosphorus removal. Background Art

[0002] Under the background of the country's "carbon peak and carbon neutrality" strategy, energy-saving wastewater treatment technology has become a research hotspot and focus in the current environmental field. Partial denitrification / anaerobic ammonia oxidation (PD / A) has attracted widespread attention due to its high efficiency and sustainable nitrogen (N) removal. However, the PD / A process cannot remove phosphorus (P). Phosphorus is an important pollutant that causes eutrophication of water bodies and is also a nutrient element necessary for the growth of plants and animals. It is directly related to human food security. Nowadays, due to excessive exploitation of phosphorus resources, there is currently a shortage problem. Therefore, it is of great significance to recover phosphorus resources from sewage. It is urgent to develop an innovative phosphorus recovery process that enables the PD / A process to achieve effective phosphorus removal and recovery while maintaining effective nitrogen removal. Summary of the invention

[0003] The purpose of the present invention is to provide a two-stage PD-HAP coupled Anammox synchronous denitrification and phosphorus removal device and method, aiming to overcome the problem that the existing PD / A process cannot remove phosphorus, and can simultaneously denitrify and remove phosphorus from water bodies, and form hydroxyapatite while removing phosphorus, which provides a good prerequisite for further recovery of phosphorus resources.

[0004] The object of the present invention is achieved as follows: a two-stage PD-HAP coupled Anammox synchronous denitrification and phosphorus removal method, using a PD / HAP reactor and an Anammox reactor for treatment, the reactor includes a water inlet and a water outlet, and a stirring device and a heating device are provided in the reactor body, comprising the following steps:

[0005] 1. Start-up of PD / HAP reactor

[0006] (1) The experiment used synthetic sewage with a COD concentration of 300 mg / L and NO3 - -N concentration is 120mg / L; at the beginning of each operation cycle, the sewage is maintained at the above concentration;

[0007] (2) The PD / HAP reactor was inoculated with laboratory-acclimated short-range denitrification floc sludge at a sludge concentration of 3000 mg / L and operated with synthetic sewage for two cycles per day. Each cycle included influent, stirring, sedimentation, and effluent time of 10 min, 120 min, 30 min, and 10 min, respectively, and the remaining time was idle time.

[0008] (3) Under the premise that the reactor NTR is ≥ 80%, Ca is added to the reactor at the beginning of each cycle.2+ Mg 2+ PO4 3- ,Ca 2+ Mg 2+ PO4 3- The input amounts were 60 mg / L, 15 mg / L, and 20 mg / L, respectively. After the phosphorus removal rate stabilized, the Ca 2+ The dosage is 120 mg / L to induce the formation of HAP to achieve the purpose of phosphorus removal; when the phosphorus removal rate is ≥80%, the startup of the PD / HAP reactor is completed;

[0009] 2. Start-up of Anammox Reactor

[0010] (1) The Anammox reactor is inoculated with anaerobic ammonium oxidation sludge. After the sludge is fed, the sludge concentration in the reactor is maintained at about 3000 mg / L. The inlet water is artificially distributed and NH4 is added. + -N and NO2 - -N concentrations were 100 mg / L and 120 mg / L;

[0011] (2) When the removal rates of ammonia nitrogen and nitrite reach above 90%, adjust the NH4 + -N and NO2 - -N concentrations were 55 and 75 mg / L to better adapt to the effluent of PD / HAP. At the same time, 0.03 g / L K3PO4, 1.50 g / L NaHCO3, 0.12 g / LMgSO4·7H2O, and 1 mL of trace element 1 and 1 mL of trace element 2 were added; the composition of trace element 1 was: 5.00 g / LEDTA, 9.17 g / LFeSO4·7H2O; the composition of trace element 2 was: : 15.0g / LEDTA, 0.24g / LCoCl2·6H2O, 0.43g / LZnSO4·7H2O, 0.99g / LMnCl2·4H2O, 0.25g / LCuS O4·5H2O, 0.22g / LNaMoO4·2H2O, 0.19g / LNiCl2·6H2O, 0.21g / LNaSeO4·6H2O, 0.014g / LH3BO4.

[0012] (3) The Anammox reactor was operated for 2 cycles per day. Each cycle included water inlet, stirring, sedimentation, and water outlet for 10 min, 360 min, 30 min, and 10 min, respectively, and the remaining time was idle time;

[0013] (4) After running for a period of time, NH4 + -N and NO2 - -N and TN removal rates remained stable, which indicated that the Anammox reactor could handle the effluent from PD / HAP;

[0014] 3. PD / HAP reactor and Anammox reactor are operated in series

[0015] (1) The Anammox reactor was connected to the effluent of PD / HAP and 55 mg / L NH4 was added + -N, the two-stage PD / HAP coupled anaerobic ammonia oxidation process for simultaneous nitrogen removal and phosphorus removal was started.

[0016] Furthermore, the effluent treated by the Anammox reaction for denitrification is further returned to the PD / HAP reactor to achieve the effect of simultaneous denitrification and phosphorus removal.

[0017] Furthermore, when the PD / HAP reactor and the Anammox reactor are started, the drainage ratio of each cycle is 50%, the pH of the sewage is controlled at 8.0-8.5, and the water temperature is controlled at 29-35°C.

[0018] Furthermore, a stirring device is provided in the reactor body in the form of a propeller blade, and the angle between the straight line formed by the lower side and the upper side of the propeller blade and the horizontal plane is 45°, so as to maintain the optimal longitudinal water turbulence and lateral turbulence levels, so that the sewage in the reactor is stirred evenly.

[0019] Compared with the prior art, the device and method for synchronous nitrogen and phosphorus removal by two-stage PD / HAP coupled Anammox provided by the present invention has the following advantages:

[0020] (1) The present invention combines short-range denitrification (PD) with hydroxyapatite (HAP). The hydrolysis of sodium acetate during the short-range denitrification process increases the pH, providing conditions for the formation of HAP.

[0021] (2) The present invention solves the problem that the traditional PD / A process cannot remove phosphorus by coupling PD / HAP with Anammox.

[0022] (3) The present invention forms hydroxyapatite precipitation by adding CaCl2, which can not only recover valuable phosphorus resources, but also promote sludge granulation and enhance the stability of PD system operation, while increasing the phosphorus recovery efficiency to 30-40%;

[0023] (4) This method has simple equipment, flexible operation and strong operability. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the structure of the device of the present invention.

[0025] Figure 2The pie charts are of the short-range denitrifying bacterial community structure, where (a) is the bacterial community structure diagram during inoculation, and (b) is the bacterial community structure diagram after domestication.

[0026] Figure 3 This is a graph showing the changes in pollutants over time during the startup of the short-range denitrification coupled hydroxyapatite (PD / HAP) reactor.

[0027] Figure 4 This is a graph showing the changes of pollutants over time during the startup and coupling process of the anaerobic ammonium oxidation reactor.

[0028] Figure 5 This is a graph showing the change in sludge particle size before and after the addition of CaCl2 in a short-range denitrification reactor. In the figure, a: CaCl2 is not added. 2+ ; b: Add 60 mg / L Ca 2+ ; c: Add 120 mg / L Ca 2+ ; d: comparison of average particle size.

[0029] In the figure, 1-water inlet tank one, 2-SBR water inlet peristaltic pump one, 3-air pump, 4-PD / HAP reactor, 5-pH, DO instrument one, 6-aeration head, 7-electric drain valve one, 8-water outlet tank one, 9-agitator one, 10-water inlet tank two, 11-SBR water inlet peristaltic pump two, 12-Anammox reactor, 13-heating rod, 14-water outlet tank two, 15-electric drain valve two, 16-pH, DO instrument two, 17-agitator two, 18-PLC control system. DETAILED DESCRIPTION

[0030] like Figure 1 As shown, a two-stage PD-HAP coupled Anammox synchronous denitrification and phosphorus removal device includes an inlet tank 1, an SBR inlet peristaltic pump 2, an air pump 3 for supplying oxygen to the water through an aeration head 6, a PD / HAP reactor 4, a pH and DO meter 5, an electric drain valve 7, an outlet tank 8, an agitator 9, an inlet tank 10, an SBR inlet peristaltic pump 11, an Anammox reactor 12, a heating rod 13, an outlet tank 14, an electric drain valve 15, a pH and DO meter 16, an agitator 17, and a PLC control system 18 for controlling the operation of the entire system.

[0031] The reactor bodies of the PD / HAP reactor 4 and the Anammox reactor 12 are provided with stirring devices in the form of propeller blades, wherein the angle between the straight line formed by the lower side and the upper side of the propeller blade and the horizontal plane is 45°, so as to maintain the best longitudinal water turbulence and transverse turbulence levels, so that the sewage in the reactor is stirred evenly.

[0032] When the device works, it proceeds as follows:

[0033] S1. Start-up of PD / HAP reactor

[0034] (1) The experiment used synthetic sewage with the following water quality: COD concentration was 300 mg / L, NO3 - -N concentration 120mg / L, experimental system as Figure 1 Each reactor is made of organic glass, and the effective volume of the PD / HAP reactor is 10L.

[0035] (2) The PD / HAP reactor was inoculated with laboratory-trained short-range denitrifying floc sludge. The short-range denitrifying bacteria were taken from the sludge in the secondary sedimentation tank of Yangzhou Tangwang Wastewater Treatment Plant. After long-term training, they had good short-range denitrification effects. Figure 2 The figure shows the composition of the bacterial community before and after domestication. The short-range denitrifying bacteria Thauera increased from 2.1% at the beginning of inoculation to 7.1% after domestication.

[0036] The inoculated sludge can also be obtained by directly mixing with commercially available short-range denitrifying bacteria. The commercially available product name is: Tauerella; manufacturer: Ruichu Biotechnology (Jiangsu) Co., Ltd.; brand: SHBCC, appearance: freeze-dried powder; active ingredient content: 99%.

[0037] The sludge concentration is 3000 mg / L, and the system runs for 2 cycles per day. Each cycle includes water inlet, stirring, sedimentation, and water outlet for 10 minutes, 120 minutes, 30 minutes, and 10 minutes respectively. The remaining time is idle time.

[0038] (3) By Figure 3 It can be seen that in the 1-30 cycles, the inoculated short-range denitrification sludge gradually recovered its activity after operation and regulation, the nitrite nitrogen in the effluent gradually increased, the nitrite nitrogen concentration gradually stabilized at 75 mg / L, and the NTR stabilized at about 83%, indicating that the appropriate short-range denitrification effect was achieved after regulation. Therefore, starting from the 31st cycle, 20 mg / L of PO4 was added to the reactor. 3- , 60mg / L Ca 2+ and 15 mg / L Mg 2+ ,Depend on Figure 3 It can be seen that with the increase of Ca 2+ The addition of PO4 3- The removal effect gradually increased over time, and the final phosphorus removal rate stabilized at about 68%. At this time, a higher concentration of Ca was added to the reactor in each cycle. 2+(120 mg / L) was used to examine its effect on phosphorus removal. It can be seen that, as before, the effect of nitrite accumulation in the short-range denitrification process was hardly affected, while phosphorus removal increased slowly, and finally the phosphorus in the effluent stabilized at around 3 mg / L, and the removal rate stabilized at 83%.

[0039] from Figure 5 It can also be seen that after adding CaCl2, the proportion of sludge with larger particle size increased significantly, and the particle size increased with the increase of CaCl2. 2+ The concentration increases, which indicates that Ca 2+ The addition of induced biomineralization in the short-range denitrification reactor, forming phosphate mineralization crystals mainly composed of hydroxyapatite, which enhanced the nitrogen and phosphorus removal effect. The NTR of the whole system was ≥80%, and the phosphorus removal rate was ≥80%, indicating that the PD / HAP system had been initially completed.

[0040] S2. Start-up of Anammox Reactor

[0041] (1) The Anammox reactor is inoculated with anaerobic ammonium oxidation sludge. The anaerobic ammonium oxidation bacteria are commercially available. Manufacturer: Shandong Luxing Environmental Protection Technology Co., Ltd.; Model: LXHJ65; Active ingredient content 90%, pH value 6.5; Brand: Luxing; The anaerobic ammonium oxidation bacteria are inoculated into the sludge treatment tank of a sewage treatment plant. The experimental inoculated sludge of the present invention is taken from the sludge treatment tank. The inoculated sludge can also be directly prepared using commercially available anaerobic ammonium oxidation bacteria. After the sludge is fed, the sludge concentration in the reactor is ensured to be about 3000 mg / L. The inlet water is artificially distributed, and NH4 is added. + -N and NO2 - -N concentrations were 100 and 120 mg / L respectively. After the reactor was successfully started, adjust the NH4 + -N and NO2 - -N concentration is 55 and 75 mg / L, which is used to better adapt to the effluent of PD / HAP. 0.03 g / L K3PO4, 1.50 g / L NaHCO3, 0.12 g / LMgSO4·7H2O, and 1 mL of trace element 1 and trace element 2 are added; trace element 1 composition (g / L): 5.00 g / LEDTA, 9.17 g / LFeSO4·7H2O; trace element 2 composition (g / L): 1 5.0g / LEDTA, 0.24g / LCoCl2·6H2O, 0.43g / LZnSO4·7H2O, 0.99g / LMnCl2·4H2O, 0.25g / LCuSO 4·5H2O, 0.22g / LNaMoO4·2H2O, 0.19g / LNiCl2·6H2O, 0.21g / LNaSeO4·6H2O, 0.014g / LH3BO4.

[0042] (2) The Anammox reactor was operated for 2 cycles per day. Each cycle included water inlet, stirring, sedimentation, and water outlet for 10 min, 360 min, 30 min, and 10 min, respectively. The remaining time was idle time.

[0043] (3) From Figure 4 It can be seen that the Anammox reactor was started within 40 cycles, at which time the removal rates of ammonia nitrogen and nitrite reached more than 90%, and the total nitrogen removal rate finally stabilized at around 85%, indicating that the anaerobic ammonium oxidation effect was good. + -N and NO2 - -N were adjusted to 55mg / L and 75mg / L respectively, which is to prepare for the sewage connected to the PD / HAP reactor. After running for a period of time, NH4 + -N and NO2 - The removal rates of -N and TN remained stable, which indicated that the Anammox reactor could handle the effluent from PD / HAP.

[0044] S3, PD / HAP reactor and Anammox reactor are operated in series

[0045] (1) The Anammox reactor was connected to the effluent of PD / HAP in the 60th cycle, and about 55 mg / L of NH4 was added + -N, from Figure 4 It can be seen that since the Anammox reactor had already adapted to the nitrogen concentration under the conditions before being connected to the PD / HAP effluent, the Anammox reactor was able to remain stable after being connected to the PD / HAP effluent, with the ammonia nitrogen and nitrite removal rates both being able to remain above 90%, and the total nitrogen removal rate being stable at around 84%. At this point, the two-stage PD / HAP coupled anaerobic ammonium oxidation process with simultaneous nitrogen removal and phosphorus removal was started and put into operation.

[0046] The effluent treated by Anammox reaction denitrification can be further returned to the PD / HAP reactor to achieve the effect of simultaneous denitrification and phosphorus removal.

[0047] When the PD / HAP reactor and the Anammox reactor are started, the drainage ratio of each cycle is 50%, the pH of the sewage is controlled at 8.0-8.5, and the water temperature is controlled at 29-35°C.

[0048] The present invention is not limited to the above-mentioned embodiments. On the basis of the technical solution disclosed in the present invention, technicians in this field can make some substitutions and deformations to some technical features therein according to the disclosed technical content without creative labor, and these substitutions and deformations are all within the protection scope of the present invention.

Claims

1. A two-stage PD-HAP coupled Anammox synchronous denitrification and phosphorus removal method, using a PD / HAP reactor and an Anammox reactor for treatment, the reactor includes a water inlet and a water outlet, and a stirring device is provided in the reactor body, characterized in that The following steps are involved: S1. Start-up of PD / HAP reactor (1) The experiment used synthetic sewage with a COD concentration of 300 mg / L and NO3 - -N concentration is 120mg / L; at the beginning of each operation cycle, the sewage is maintained at the above concentration; (2) The PD / HAP reactor was inoculated with laboratory-acclimated short-range denitrification floc sludge at a sludge concentration of 3000 mg / L and operated with synthetic sewage for two cycles per day. Each cycle included water inlet, stirring, sedimentation, and water outlet for 10 min, 120 min, 30 min, and 10 min, respectively, and the remaining time was idle time. (3) Under the premise that the reactor NTR is ≥ 80%, Ca is added to the reactor at the beginning of each cycle. 2+ Mg 2+ PO4 3- ,Ca 2 + Mg 2+ PO4 3- The input amounts were 60 mg / L, 15 mg / L, and 20 mg / L, respectively. After the phosphorus removal rate stabilized, the Ca 2+ The dosage is 120 mg / L to induce the formation of HAP to achieve the purpose of phosphorus removal; when the phosphorus removal rate is ≥80%, the startup of the PD / HAP reactor is completed; S2. Start-up of Anammox Reactor (1) The Anammox reactor is inoculated with anaerobic ammonium oxidation sludge. After the sludge is added, the sludge concentration in the reactor is maintained at about 3000 mg / L. The inlet water is artificially distributed and NH4 is added. + -N and NO2 - -N concentrations were 100 mg / L and 120 mg / L; (2) When the removal rates of ammonia nitrogen and nitrite reach above 90%, adjust the NH4 + -N and NO2 - -N concentrations were 55 and 75 mg / L to better adapt to the effluent of PD / HAP. At the same time, 0.03 g / L K3PO4, 1.50 g / L NaHCO3, 0.12 g / LMgSO4·7H2O, and 1 mL of trace element 1 and 1 mL of trace element 2 were added; the composition of trace element 1 was: 5.00 g / LEDTA, 9.17 g / LFeSO4·7H2O; the composition of trace element 2 was: For: 15.0g / LEDTA, 0.24g / LCoCl2·6H2O, 0.43g / LZnSO4·7H2O, 0.99g / LMnCl2·4H2O, 0.25g / LCu SO4·5H2O, 0.22g / LNaMoO4·2H2O, 0.19g / LNiCl2·6H2O, 0.21g / LNaSeO4·6H2O, 0.014g / LH3BO 4； (3) The Anammox reactor was operated for 2 cycles per day. Each cycle included water inlet, stirring, sedimentation, and water outlet for 10 min, 360 min, 30 min, and 10 min, respectively. The remaining time was idle time. (4) After running for a period of time, NH4 + -N and NO2 - -N and TN removal rates remained stable, which indicated that the Anammox reactor could handle the effluent from PD / HAP; S3, PD / HAP reactor and Anammox reactor are operated in series (1) The Anammox reactor was connected to the effluent of PD / HAP and 55 mg / L NH4 was added. + -N, the two-stage PD / HAP coupled anaerobic ammonium oxidation process and synchronous nitrogen removal and phosphorus removal process were started and operated continuously.

2. A two-stage PD-HAP coupled Anammox synchronous denitrification and phosphorus removal method according to claim 1, characterized in that: The effluent treated by Anammox reaction for denitrification is further returned to the PD / HAP reactor to achieve the effect of simultaneous denitrification and phosphorus removal.

3. A two-stage PD-HAP coupled Anammox synchronous denitrification and phosphorus removal method according to claim 1, characterized in that: When the PD / HAP reactor and the Anammox reactor are started, the drainage ratio of each cycle is 50%, the pH of the sewage is controlled at 8.0-8.5, and the water temperature is controlled at 29-35°C.

4. A two-stage PD-HAP coupled Anammox synchronous denitrification and phosphorus removal method according to claim 1, characterized in that: The reactor body is equipped with a stirring device in the form of a propeller blade. The angle between the straight line formed by the lower side and the upper side of the propeller blade and the horizontal plane is 45° to maintain the optimal longitudinal water turbulence and lateral turbulence levels so that the sewage in the reactor is evenly stirred.

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