Device and method for realizing efficient recovery of phosphorus and PHAs by fermenting and denitrifying phosphorus removal granular sludge

Abstract

The invention discloses a device and a method for realizing efficient recovery of phosphorus and PHAs by fermenting denitrifying phosphorus removal granular sludge, and belongs to the technical field of biological sewage treatment. The device comprises a non-biodegradable carbon source, an ammonia nitrogen and phosphate water inlet tank, a nitrate nitrogen water inlet tank, a granular sludge reactor, a PHAs recycling tank, a phosphorus and ammonia nitrogen water outlet tank, a magnesium solution water inlet tank, a struvite reactor, a phosphorus recycling tank, a water outlet tank and an online monitoring system. The method comprises the following steps: an anaerobic stage: converting a non-biodegradable carbon source into an easily biodegradable carbon source, storing the easily biodegradable carbon source as PHAs and releasing phosphorus, discharging supernatant and granular sludge in the anaerobic stage to realize phosphorus and PHAs recovery, and meanwhile, promoting sludge granulation by regulating and controlling water feeding without stirring and precipitation time; and in the anoxic stage, denitrification and synchronous phosphorus uptake are realized. According to the invention, the technical problems that denitrifying phosphorus removal bacteria cannot utilize a non-biodegradable carbon source to realize synchronous recovery of phosphorus and PHAs, and the formation of struvite needs to regulate and control phosphate and pH are solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of biological sewage treatment. Specifically, it particularly relates to a device and method for efficiently recovering phosphorus and PHAs by using fermentative denitrifying phosphorus-removing granular sludge. Background Art

[0002] Phosphorus is one of the indispensable elements for agricultural production. With the growth of the population and the increase in food demand, the demand for phosphorus shows a significant upward trend.

[0003] The aerobic phosphorus-removing technology can recover phosphorus resources by discharging flocculent sludge at the end of the aerobic stage. However, the aerobic phosphorus-removing technology requires a large amount of oxygen and carbon sources, and the synchronous recovery of PHAs cannot be achieved. At the same time, due to the characteristics of low biomass and poor sedimentation of the flocculent sludge used in the aerobic phosphorus-removing technology, its phosphorus recovery load is limited.

[0004] The denitrifying phosphorus-removing technology is also mentioned in the prior art. The denitrifying phosphorus-removing technology can synchronously recover phosphorus resources and remove nitrate nitrogen pollutants. Compared with the aerobic phosphorus-removing technology, the denitrifying phosphorus-removing technology can save about 50% of the carbon source consumption and 30% of the aeration volume. However, the denitrifying phosphorus-removing technology recovers phosphorus resources by discharging flocculent sludge at the end of the anoxic stage, and the synchronous recovery of PHAs still cannot be achieved. In addition, the flocculent sludge used in the denitrifying phosphorus-removing technology has the characteristics of low biomass and poor sedimentation, which also causes the limitation of the phosphorus recovery load.

[0005] Meanwhile, the existing aerobic phosphorus-removing technology and denitrifying phosphorus-removing technology in the prior art can only utilize the easily biodegradable carbon sources in sewage, but the easily biodegradable carbon sources are often scarce in sewage. At the same time, more than 50% of the recalcitrant carbon sources in sewage cannot be utilized. In addition, in order to achieve efficient phosphorus removal, it is usually necessary to additionally add easily biodegradable carbon sources, which significantly increases the cost of phosphorus recovery.

[0006] Currently, the recovery of phosphorus resources is usually achieved by the method of struvite crystallization. Struvite (NH4MgPO4•6H2O) is composed of ammonia nitrogen, phosphate and magnesium salt, and is more likely to form when the pH value is greater than 8.0. Therefore, during the formation of struvite, it is often necessary to externally add ammonia nitrogen and pH regulators, which increases the operation complexity and cost.

[0007] Therefore, the applicant believes that how to efficiently recover phosphorus and PHAs while making full use of recalcitrant carbon sources, and enabling struvite not to require additional addition of ammonia nitrogen and pH regulators during the recovery process, is a technical problem that needs to be solved by those skilled in the art. Summary of the Invention

[0008] The object of the present invention is to provide a device and method for efficiently recovering phosphorus and PHAs from fermentative denitrifying phosphorus-removing granular sludge, so as to realize the efficient recovery of phosphorus and PHAs based on the phosphorus-rich supernatant discharged at the end of anaerobic stage and granular sludge while making full use of poorly biodegradable carbon sources. And the present invention realizes no need for additional ammonia nitrogen and pH regulator during struvite recovery by regulating the concentrations of phosphorus and ammonia nitrogen in real time and utilizing the characteristic of natural increase in pH value during the denitrifying phosphorus-removing process.

[0009] To achieve the above technical object, the present application is realized by the following technical solutions: The device for efficiently recovering phosphorus and PHAs from fermentative denitrifying phosphorus-removing granular sludge described in the present invention includes a poorly biodegradable carbon source, an ammonia nitrogen and phosphate inlet water tank, a nitrate nitrogen inlet water tank, a granular sludge reactor, a PHAs recovery tank, a phosphorus and ammonia nitrogen outlet water tank, a magnesium solution inlet water tank, a struvite reactor, a phosphorus recovery tank, an outlet water tank and an on-line monitoring and control system which are connected in sequence; wherein the poorly biodegradable carbon source, the ammonia nitrogen and phosphate inlet water tank is connected to the granular sludge reactor through a first inlet water pump; the nitrate nitrogen inlet water tank is connected to the granular sludge reactor through a second inlet water pump; the PHAs recovery tank is connected to the granular sludge reactor through a first sludge discharge pump; the phosphorus and ammonia nitrogen outlet water tank is connected to the granular sludge reactor through a first drainage pump; the phosphorus and ammonia nitrogen outlet water tank is connected to the struvite reactor through a third inlet water pump; the magnesium solution inlet water tank is connected to the struvite reactor through a fourth inlet water pump; the phosphorus recovery tank is connected to the struvite reactor through a second sludge discharge pump; the outlet water tank is connected to the struvite reactor through a second drainage pump; the granular sludge reactor is connected to the on-line monitoring and control system through a first phosphate concentration sensor, a nitrate concentration sensor, a pH value sensor and an ammonia nitrogen concentration sensor; the struvite reactor is connected to the on-line monitoring and control system through a second phosphate concentration sensor; The poorly biodegradable carbon source, the ammonia nitrogen and phosphate inlet water tank is provided with a first overflow pipe and a first vent valve; The nitrate nitrogen inlet water tank is provided with a second overflow pipe and a second vent valve; The granular sludge reactor is provided with a first stirrer, a first inlet water pump, a second inlet water pump, a first sludge discharge pump, a first drainage pump, a first phosphate concentration sensor, a nitrate concentration sensor, a pH value sensor and an ammonia nitrogen concentration sensor; The PHAs recovery tank is provided with a third overflow pipe and a third vent valve; The phosphorus and ammonia nitrogen outlet water tank is provided with a fourth overflow pipe and a fourth vent valve; The magnesium solution inlet water tank is provided with a fifth overflow pipe and a fifth vent valve; The struvite reactor is provided with a third inlet water pump, a fourth inlet water pump, a second stirrer, a third stirrer, a second phosphate concentration sensor, a second sludge discharge pump and a second drainage pump; The phosphorus recovery tank is configured with a sixth overflow pipe and a sixth vent valve; The water outlet tank is configured with a seventh overflow pipe and a seventh vent valve; The on-line monitoring and control system includes a first inlet water pump relay, a pH sensor relay, an ammonia nitrogen concentration sensor relay, a first stirrer relay, a first phosphate concentration sensor relay, a nitrate concentration sensor relay, a first sludge discharge pump relay, a first drainage pump relay, a second inlet water pump relay, a third inlet water pump relay, a second stirrer relay, a third stirrer relay, a second phosphate concentration sensor relay, a second sludge discharge pump relay, a fourth inlet water pump relay, a second drainage pump relay, a signal adapter A / D conversion interface, a signal adapter D / A conversion interface and a computer; The first inlet water pump relay of the on-line monitoring and control system is connected to the first inlet water pump; the pH sensor relay is connected to the pH sensor; the ammonia nitrogen concentration sensor relay is connected to the ammonia nitrogen concentration sensor; the first stirrer relay is connected to the first stirrer; the first phosphate concentration sensor relay is connected to the first phosphate concentration sensor; the nitrate concentration sensor relay is connected to the nitrate concentration sensor; the first sludge discharge pump relay is connected to the first sludge discharge pump; the first drainage pump relay is connected to the first drainage pump; the second inlet water pump relay is connected to the second inlet water pump; the third inlet water pump relay is connected to the third inlet water pump; the second stirrer relay is connected to the second stirrer; the third stirrer relay is connected to the third stirrer; the second phosphate concentration sensor relay is connected to the second phosphate concentration sensor; the second sludge discharge pump relay is connected to the second sludge discharge pump; the fourth inlet water pump relay is connected to the fourth inlet water pump; the second drainage pump relay is connected to the second drainage pump; the on-line monitoring and control system converts analog signals into digital signals through the signal adapter A / D conversion interface and a cable and transmits them to the computer; the computer transmits digital instructions to the on-line monitoring and control system through a cable and the signal adapter D / A conversion interface.

[0010] The present invention also provides a method for efficiently recovering phosphorus and PHAs by applying fermentative denitrifying phosphorus-removing granular sludge in a device for efficiently recovering phosphorus and PHAs by using fermentative denitrifying phosphorus-removing granular sludge, comprising the following steps: I. Cultivation of fermentative denitrifying phosphorus-removing granular sludge: 1) Add the activated sludge from a sewage treatment plant to the granular sludge reactor, and control the sludge concentration at 2000 mg / L - 8000 mg / L; 2) Start the first inlet water pump, and pump the inlet water of a hardly biodegradable carbon source, ammonia nitrogen and phosphate with a volume of V1 into the granular sludge reactor, and control V1 to be 40% - 80% of the effective volume V of the reactor; 3) Control the static time to be greater than 1 h, start the first drainage pump, and pump the supernatant containing phosphate and ammonia nitrogen with a volume of V2 into the phosphorus and ammonia nitrogen outlet water tank, and control V2 to be 30%-90% of V1; 4) Start the first stirrer and stop stirring when the sewage and sludge are fully mixed; 5) Control the precipitation time to be less than 20 min, start the first sludge discharge pump, and discharge the fermentative denitrifying phosphorus-removing granular sludge with a volume of V3 into the PHA recovery tank, where V3 is the difference between V1 and V2; 6) Start the second inlet water pump, pump the nitrate nitrogen with a volume of V4 into the granular sludge reactor, and control the molar ratio of nitrate nitrogen to phosphate in the granular sludge reactor to be greater than 1.5; 7) Start the first stirrer and stop stirring when the nitrate nitrogen concentration drops to 0 mg / L; 8) Control the precipitation time to be greater than 10 min, start the first drainage pump, and pump the supernatant with a volume of V4 into the phosphorus and ammonia nitrogen outlet water tank; 9) Repeat steps 2-8 until the proportion of granular sludge with a particle size greater than 200 μm in the mixed sludge is greater than 30%, and control the precipitation time in step 5 to be less than 10 min; 10) Repeat steps 2-8 until the proportion of granular sludge with a particle size greater than 200 μm in the mixed sludge is greater than 50%, the molar ratio of phosphate to ammonia nitrogen in the anaerobic-end granular sludge reactor is greater than 1.0, and at the same time the pH value in the anoxic-end granular sludge reactor is greater than 8.5, indicating that the cultivation of fermentative denitrifying phosphorus-removing granular sludge is finally achieved; II. Struvite recovery: 1) Start the third inlet water pump, and pump the ammonia nitrogen and phosphate with a volume of V5 into the struvite reactor, where V5 is the sum of V2 and V4; 2) Start the fourth inlet water pump, pump the magnesium solution into the struvite reactor, and control the molar ratio of magnesium ions to phosphate ions to be 1.0; 3) Start the second stirrer and the third stirrer, and stop stirring when the phosphate concentration drops to 0 mg / L; 4) Control the precipitation time to be greater than 10 min, start the second drainage pump, and discharge the effluent into the outlet water tank; 5) Start the second sludge discharge pump, discharge the struvite precipitate into the phosphorus recovery tank, and finally recover the phosphorus resources in the form of struvite.

[0011] Compared with the prior art, the present invention has the following beneficial effects: 1. Compared with the denitrifying phosphorus-removing technology, the fermentative denitrifying phosphorus-removing granular sludge cultivated by the present invention can make full use of the hardly biodegradable carbon source.

[0012] 2. Compared with traditional aerobic phosphorus removal and denitrifying phosphorus removal technologies, the present invention solves the technical problem of the difficult synchronous recovery of phosphorus and PHAs by means of recovering phosphorus-rich supernatant and granular sludge at the end of anaerobic stage.

[0013] 3. Compared with aerobic phosphorus removal and denitrifying phosphorus removal technologies, the granular sludge adopted in the present invention can significantly increase the biomass per unit volume and sedimentation performance in the reactor, thereby significantly increasing the recovery load of phosphorus and PHAs.

[0014] 4. Compared with aerobic phosphorus removal technology, the fermentative denitrifying phosphorus-removing granular sludge cultivated in the present invention can reduce the carbon source required for aerobic respiration, thereby significantly increasing the yield of PHAs. In addition, the present invention can also achieve synchronous nitrogen removal and further increase the yield of PHAs by saving the carbon source required for nitrogen removal.

[0015] 5. The present invention provides a method for granulation of fermentative denitrifying phosphorus-removing sludge, which promotes the formation of granular sludge by not stirring the anaerobic influent, strengthening the storage of internal carbon source by fermentation and regulating the sedimentation time.

[0016] 6. The present invention provides an economical and efficient method for recovering struvite. By regulating the concentrations of phosphorus and ammonia nitrogen in real time and utilizing the characteristic of the natural increase of pH value during the denitrifying phosphorus removal process, no additional ammonia nitrogen and pH regulator are required during the struvite recovery process, effectively reducing the cost of phosphorus recovery. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic structural diagram of the device for realizing the efficient recovery of phosphorus and PHAs by the fermentative denitrifying phosphorus-removing granular sludge described in the present invention.

[0018] In the figure: 1 is a water inlet tank for recalcitrant carbon source, ammonia nitrogen and phosphate, 2 is a water inlet tank for nitrate nitrogen, 3 is a granular sludge reactor, 4 is a PHAs recovery tank, 5 is a water outlet tank for phosphorus and ammonia nitrogen, 6 is a magnesium solution inlet tank, 7 is a struvite reactor, 8 is a phosphorus recovery tank, 9 is a water outlet tank, 10 is an on-line monitoring and control system; 1.1 is a first overflow pipe, 1.2 is a first emptying valve; 2.1 is a second overflow pipe, 2.2 is a second emptying valve; 3.1 is a first stirrer, 3.2 is a first water inlet pump, 3.3 is a second water inlet pump, 3.4 is a first sludge discharge pump, 3.5 is a first water discharge pump, 3.6 is a first phosphate concentration sensor, 3.7 is a nitrate concentration sensor, 3.8 is a pH value sensor, 3.9 is an ammonia nitrogen concentration sensor; 4.1 is a third overflow pipe, 4.2 is a third emptying valve; 5.1 is a fourth overflow pipe, 5.2 is a fourth emptying valve; 6.1 is a fifth overflow pipe, 6.2 is a fifth emptying valve; 7.1 is a third water inlet pump, 7.2 is a fourth water inlet pump, 7.3 is a second stirrer, 7.4 is a third stirrer, 7.5 is a second phosphate concentration sensor, 7.6 is a second sludge discharge pump, 7.7 is a second water discharge pump; 8.1 is a sixth overflow pipe, 8.2 is a sixth emptying valve; 9.1 is a seventh overflow pipe, 9.2 is a seventh emptying valve; 10.1 is a first water inlet pump relay, 10.2 is a pH value sensor relay, 10.3 is an ammonia nitrogen concentration sensor relay, 10.4 is a first stirrer relay, 10.5 is a first phosphate concentration sensor relay, 10.6 is a nitrate concentration sensor relay, 10.7 is a first sludge discharge pump relay, 10.8 is a first water discharge pump relay, 10.9 is a second water inlet pump relay, 10.10 is a third water inlet pump relay, 10.11 is a second stirrer relay, 10.12 is a third stirrer relay, 10.13 is a second phosphate concentration sensor relay, 10.14 is a second sludge discharge pump relay, 10.15 is a fourth water inlet pump relay, 10.16 is a second water discharge pump relay, 10.17 is a signal adapter A / D conversion interface, 10.18 is a signal adapter D / A conversion interface, 10.19 is a computer. Detailed implementation mode

[0019] The present invention will be further described below in conjunction with the drawings and embodiments.

[0020] The technical principle of the present invention is as follows: Using the activated sludge from a sewage treatment plant as the seed sludge, during anaerobic influent, the recalcitrant carbon source is fermented and converted into an easily biodegradable carbon source, while being stored as intracellular PHAs and releasing phosphorus; at the end of the anaerobic stage, the supernatant and granular sludge are respectively discharged to achieve efficient recovery of phosphorus and PHAs. During this process, through anaerobic non-stirring, fermentation enhancement, and screening of sedimentation time control, the formation of dense fermentative denitrifying phosphorus-removing granular sludge is promoted. In the anoxic stage, the remaining granular sludge utilizes intracellular PHAs to achieve phosphorus uptake, nitrogen removal, and generate alkalinity to increase the pH value. The present invention can efficiently achieve the synchronous recovery of phosphorus and PHAs on the basis of making full use of the recalcitrant carbon source, and at the same time solve the technical problems of adding ammonia nitrogen and pH regulators during the struvite recovery process.

[0021] Example 1: As Figure 1 shown, a device for efficiently recovering phosphorus and PHAs by fermentative denitrifying phosphorus-removing granular sludge includes a recalcitrant carbon source, an ammonia nitrogen and phosphate inlet water tank 1, a nitrate nitrogen inlet water tank 2, a granular sludge reactor 3, a PHAs recovery tank 4, a phosphorus and ammonia nitrogen outlet water tank 5, a magnesium solution inlet water tank 6, a struvite reactor 7, a phosphorus recovery tank 8, an outlet water tank 9, and an on-line monitoring and control system 10, which are connected in sequence; wherein the recalcitrant carbon source, ammonia nitrogen and phosphate inlet water tank 1 is connected to the granular sludge reactor 3 through a first inlet water pump 3.2; the nitrate nitrogen inlet water tank 2 is connected to the granular sludge reactor 3 through a second inlet water pump 3.3; the PHAs recovery tank 4 is connected to the granular sludge reactor 3 through a first sludge discharge pump 3.4; the phosphorus and ammonia nitrogen outlet water tank 5 is connected to the granular sludge reactor 3 through a first drainage pump 3.5; the phosphorus and ammonia nitrogen outlet water tank 5 is connected to the struvite reactor 7 through a third inlet water pump 7.1; the magnesium solution inlet water tank 6 is connected to the struvite reactor 7 through a fourth inlet water pump 7.2; the phosphorus recovery tank 8 is connected to the struvite reactor 7 through a second sludge discharge pump 7.6; the outlet water tank 9 is connected to the struvite reactor 7 through a second drainage pump 7.7; the granular sludge reactor 3 is connected to the on-line monitoring and control system 10 through a first phosphate concentration sensor 3.6, a nitrate concentration sensor 3.7, a pH value sensor 3.8, and an ammonia nitrogen concentration sensor 3.9; the struvite reactor 7 is connected to the on-line monitoring and control system 10 through a second phosphate concentration sensor 7.5.

[0022] Among them, the refractory biodegradable carbon source, ammonia nitrogen and phosphate inlet water tank 1 is equipped with a first overflow pipe 1.1 and a first drain valve 1.2; the nitrate nitrogen inlet water tank 2 is equipped with a second overflow pipe 2.1 and a second drain valve 2.2; the granular sludge reactor 3 is equipped with a first stirrer 3.1, a first water inlet pump 3.2, a second water inlet pump 3.3, a first sludge discharge pump 3.4, a first drain pump 3.5, a first phosphate concentration sensor 3.6, a nitrate concentration sensor 3.7, a pH value sensor 3.8 and an ammonia nitrogen concentration sensor 3.9; the PHAs recovery tank 4 is equipped with a third overflow pipe 4.1 and a third drain valve 4.2; the phosphorus and ammonia nitrogen outlet water tank 5 is equipped with a fourth overflow pipe 5.1 and a fourth drain valve 5.2; the magnesium solution inlet water tank 6 is equipped with a fifth overflow pipe 6.1 and a fifth drain valve 6.2; the struvite reactor 7 is equipped with a third water inlet pump 7.1, a fourth water inlet pump 7.2, a second stirrer 7.3, a third stirrer 7.4, a second phosphate concentration sensor 7.5, a second sludge discharge pump 7.6 and a second drain pump 7.7; the phosphorus recovery tank 8 is equipped with a sixth overflow pipe 8.1 and a sixth drain valve 8.2; the outlet water tank 9 is equipped with a seventh overflow pipe 9.1 and a seventh drain valve 9.2; the on-line monitoring and control system 10 includes a first water inlet pump relay 10.1, a pH value sensor relay 10.2, an ammonia nitrogen concentration sensor relay 10.3, a first stirrer relay 10.4, a first phosphate concentration sensor relay 10.5, a nitrate concentration sensor relay 10.6, a first sludge discharge pump relay 10.7, a first drain pump relay 10.8, a second water inlet pump relay 10.9, a third water inlet pump relay 10.10, a second stirrer relay 10.11, a third stirrer relay 10.12, a second phosphate concentration sensor relay 10.13, a second sludge discharge pump relay 10.14, a fourth water inlet pump relay 10.15, a second drain pump relay 10.16, a signal converter A / D transfer interface 10.17, a signal converter D / A transfer interface 10.18 and a computer 10.19.Among them, the first influent pump relay 10.1 of the on-line monitoring and control system 10 is connected to the first influent pump 3.2; the pH sensor relay 10.2 is connected to the pH sensor 3.8; the ammonia nitrogen concentration sensor relay 10.3 is connected to the ammonia nitrogen concentration sensor 3.9; the first agitator relay 10.4 is connected to the first agitator 3.1; the first phosphate concentration sensor relay 10.5 is connected to the first phosphate concentration sensor 3.6; the nitrate concentration sensor relay 10.6 is connected to the nitrate concentration sensor 3.7; the first sludge discharge pump relay 10.7 is connected to the first sludge discharge pump 3.4; the first drainage pump relay 10.8 is connected to the first drainage pump 3.5; the second influent pump relay 10.9 is connected to the second influent pump 3.3; the third influent pump relay 10.10 is connected to the third influent pump 7.1; the second agitator relay 10.11 is connected to the second agitator 7.3; the third agitator relay 10.12 is connected to the third agitator 7.4; the second phosphate concentration sensor relay 10.13 is connected to the second phosphate concentration sensor 7.5; the second sludge discharge pump relay 10.14 is connected to the second sludge discharge pump 7.6; the fourth influent pump relay 10.15 is connected to the fourth influent pump 7.2; the second drainage pump relay 10.16 is connected to the second drainage pump 7.7; the on-line monitoring and control system 10 converts the analog signal into a digital signal through the signal adapter A / D transfer interface 10.17 and the cable and transmits it to the computer 10.19; the computer 10.19 transmits the digital instruction to the on-line monitoring and control system 10 through the cable and the signal adapter D / A transfer interface 10.18.

[0023] During the test, starch, ammonium chloride, dipotassium hydrogen phosphate, tap water and 0.3 ml / L nutrient solution were used to simulate the influent of refractory biodegradable carbon source, ammonia nitrogen and phosphate. Among them, the concentrations of refractory biodegradable carbon source, ammonia nitrogen and phosphate were 800 mg COD / L, 50 mg N / L and 6 mg P / L respectively; sodium nitrate and tap water were used to simulate the influent of nitrate nitrogen, and the nitrate nitrogen concentration was 20 mg N / L; magnesium chloride hexahydrate and tap water were used to simulate the influent of magnesium solution, and the magnesium ion concentration was 500 mg / L. The nutrient solution components included: 5 g / L EDTA, 5 g / L FeSO4, 15 g / L EDTA, 0.014 g / L H3BO3, 0.25 g / L CuSO4·5H2O, 0.22 g / L NaMoO4·2H2O, 0.99 g / L MnCl2·4H2O, 0.43 ZnSO4·7H2O, 0.19 g / L NiCl2·6H2O.

[0024] The test reactor is as Figure 1 shown, and the volumes of the granular sludge reactor 3 and the struvite reactor 7 are 10 L and 14 L respectively.

[0025] The specific operation is as follows: I. Cultivation of fermentative denitrifying phosphorus-removing granular sludge: 1) Add the activated sludge from the sewage treatment plant to the granular sludge reactor 3, and control the sludge concentration at 6000 mg / L; 2) Start the first inlet pump 3.2, and pump 6 L of influent containing refractory biodegradable carbon source, ammonia nitrogen and phosphate into the granular sludge reactor 3; 3) Control the static time at 2 h, start the first drain pump 3.5, and pump 5 L of supernatant containing phosphate and ammonia nitrogen into the phosphorus and ammonia nitrogen outlet water tank 5; 4) Start the first stirrer 3.1, and stop stirring when the sewage and sludge are fully mixed; 5) Control the sedimentation time at 10 min, start the first sludge discharge pump 3.4, and discharge 1 L of fermentative denitrifying phosphorus-removing granular sludge into the PHAs recovery tank 4; 6) Start the second inlet pump 3.3, and pump 4 L of nitrate nitrogen into the granular sludge reactor 3, and control the molar ratio of nitrate nitrogen to phosphate in the granular sludge reactor 3 at 1.7; 7) Start the first stirrer 3.1, and stop stirring when the nitrate nitrogen concentration drops to 0 mg / L; 8) Control the sedimentation time at 20 min, start the first drain pump 3.5, and pump 4 L of supernatant into the phosphorus and ammonia nitrogen outlet water tank 5; 9) Repeat steps 2 - 8 until the proportion of granular sludge with a particle size greater than 200 μm in the mixed sludge is 45%, and control the sedimentation time in step 5 at 5 min; 10) Repeat steps 2 - 8 until the proportion of granular sludge with a particle size greater than 200 μm in the mixed sludge is 70%, the molar ratio of phosphate to ammonia nitrogen in the anaerobic end granular sludge reactor 3 is 1.2, and the pH value in the anoxic end granular sludge reactor 3 is 8.6, indicating that the cultivation of fermentative denitrifying phosphorus-removing granular sludge is finally achieved.

[0026] II. Struvite recovery: 1) Start the third inlet pump 7.1, and pump 9 L of ammonia nitrogen and phosphate into the struvite reactor 7; 2) Start the fourth inlet pump 7.2, and pump the magnesium solution into the struvite reactor 7, and control the molar ratio of magnesium ions to phosphate ions at 1.0; 3) Start the second stirrer 7.3 and the third stirrer 7.4, and stop stirring when the phosphate concentration drops to 0 mg / L; 4) Control the sedimentation time at 30 min, start the second drain pump 7.7, and discharge the effluent into the outlet water tank 9; 5) Start the second sludge pump 7.6 to discharge the struvite precipitate into the phosphorus recovery tank 8, and finally realize the recovery of phosphorus resources in the form of struvite.

[0027] The test results show that in the fermentative denitrifying phosphorus-removing granular sludge, the proportion of particles with a particle size greater than 200 μm is 70%. Under the condition that the starch utilization rate reaches 69%, the PHAs content can reach 0.23 g / g of sludge, and the phosphorus recovery rate is 92%. Among them, phosphorus is recovered in the form of struvite, and the average particle size of the struvite particles is 0.50 mm, and the purity is 85%.

[0028] Finally, although this specification is described according to the embodiments, not every embodiment only contains an independent technical solution. This narrative way of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. An apparatus for efficiently recovering phosphorus and PHAs by fermentative denitrifying phosphorus-removing granular sludge, characterized in that It includes a refractory biodegradable carbon source, ammonia nitrogen and phosphate inlet water tank (1), a nitrate nitrogen inlet water tank (2), a granular sludge reactor (3), a PHAs recovery tank (4), a phosphorus and ammonia nitrogen outlet water tank (5), a magnesium solution inlet water tank (6), a struvite reactor (7), a phosphorus recovery tank (8), an outlet water tank (9) and an on-line monitoring and control system (10) which are connected in sequence; wherein the refractory biodegradable carbon source, ammonia nitrogen and phosphate inlet water tank (1) is connected to the granular sludge reactor (3) through a first inlet water pump (3.2); the nitrate nitrogen inlet water tank (2) is connected to the granular sludge reactor (3) through a second inlet water pump (3.3); the PHAs recovery tank (4) is connected to the granular sludge reactor (3) through a first sludge discharge pump (3.4); the phosphorus and ammonia nitrogen outlet water tank (5) is connected to the granular sludge reactor (3) through a first drainage pump (3.5); the phosphorus and ammonia nitrogen outlet water tank (5) is connected to the struvite reactor (7) through a third inlet water pump (7.1); the magnesium solution inlet water tank (6) is connected to the struvite reactor (7) through a fourth inlet water pump (7.2); the phosphorus recovery tank (8) is connected to the struvite reactor (7) through a second sludge discharge pump (7.6); the outlet water tank (9) is connected to the struvite reactor (7) through a second drainage pump (7.7); the granular sludge reactor (3) is connected to the on-line monitoring and control system (10) through a first phosphate concentration sensor (3.6), a nitrate concentration sensor (3.7), a pH value sensor (3.8) and an ammonia nitrogen concentration sensor (3.9); the struvite reactor (7) is connected to the on-line monitoring and control system (10) through a second phosphate concentration sensor (7.5); Wherein the refractory biodegradable carbon source, ammonia nitrogen and phosphate inlet water tank (1) is equipped with a first overflow pipe (1.1) and a first emptying valve (1.2); The nitrate nitrogen inlet water tank (2) is equipped with a second overflow pipe (2.1) and a second emptying valve (2.2); The granular sludge reactor (3) is equipped with a first stirrer (3.1), a first inlet water pump (3.2), a second inlet water pump (3.3), a first sludge discharge pump (3.4), a first drainage pump (3.5), a first phosphate concentration sensor (3.6), a nitrate concentration sensor (3.7), a pH value sensor (3.8) and an ammonia nitrogen concentration sensor (3.9); The PHAs recovery tank (4) is equipped with a third overflow pipe (4.1) and a third emptying valve (4.2); The phosphorus and ammonia nitrogen outlet water tank (5) is equipped with a fourth overflow pipe (5.1) and a fourth emptying valve (5.2); The magnesium solution inlet water tank (6) is equipped with a fifth overflow pipe (6.1) and a fifth emptying valve (6.2); The struvite reactor (7) is equipped with a third inlet water pump (7.1), a fourth inlet water pump (7.2), a second stirrer (7.3), a third stirrer (7.4), a second phosphate concentration sensor (7.5), a second sludge discharge pump (7.6) and a second drainage pump (7.7); The phosphorus recovery tank (8) is equipped with a sixth overflow pipe (8.1) and a sixth emptying valve (8.2); The water outlet tank (9) is configured with a seventh overflow pipe (9.1) and a seventh drain valve (9.2); The on-line monitoring and control system (10) includes a first inlet water pump relay (10.1), a pH value sensor relay (10.2), an ammonia nitrogen concentration sensor relay (10.3), a first stirrer relay (10.4), a first phosphate concentration sensor relay (10.5), a nitrate concentration sensor relay (10.6), a first sludge discharge pump relay (10.7), a first drain pump relay (10.8), a second inlet water pump relay (10.9), a third inlet water pump relay (10.10), a second stirrer relay (10.11), a third stirrer relay (10.12), a second phosphate concentration sensor relay (10.13), a second sludge discharge pump relay (10.14), a fourth inlet water pump relay (10.15), a second drain pump relay (10.16), a signal adapter A / D conversion interface (10.17), a signal adapter D / A conversion interface (10.18) and a computer (10.19); The first inlet water pump relay (10.1) of the on-line monitoring and control system (10) is connected to the first inlet water pump (3.2); the pH value sensor relay (10.2) is connected to the pH value sensor (3.8); the ammonia nitrogen concentration sensor relay (10.3) is connected to the ammonia nitrogen concentration sensor (3.9); the first stirrer relay (10.4) is connected to the first stirrer (3.1); the first phosphate concentration sensor relay (10.5) is connected to the first phosphate concentration sensor (3.6); the nitrate concentration sensor relay (10.6) is connected to the nitrate concentration sensor (3.7); the first sludge discharge pump relay (10.7) is connected to the first sludge discharge pump (3.4); the first drain pump relay (10.8) is connected to the first drain pump (3.5); the second inlet water pump relay (10.9) is connected to the second inlet water pump (3.3); the third inlet water pump relay (10.10) is connected to the third inlet water pump (7.1); the second stirrer relay (10.11) is connected to the second stirrer (7.3); the third stirrer relay (10.12) is connected to the third stirrer (7.4); the second phosphate concentration sensor relay (10.13) is connected to the second phosphate concentration sensor (7.5); the second sludge discharge pump relay (10.14) is connected to the second sludge discharge pump (7.6); the fourth inlet water pump relay (10.15) is connected to the fourth inlet water pump (7.2); the second drain pump relay (10.16) is connected to the second drain pump (7.7); the on-line monitoring and control system (10) converts the analog signal into a digital signal through the signal adapter A / D conversion interface (10.17) and a cable and transmits it to the computer (10.19); the computer (10.19) transmits the digital instruction to the on-line monitoring and control system (10) through a cable and the signal adapter D / A conversion interface (10.18).

2. A device for efficiently recovering phosphorus and PHAs by applying the fermentative denitrifying phosphorus-removing granular sludge described in claim 1 implements a method for efficiently recovering phosphorus and PHAs by using the fermentative denitrifying phosphorus-removing granular sludge, characterized in that, Comprising the following steps: I. Cultivation of fermentative denitrifying phosphorus-removing granular sludge: 1) Add the activated sludge from the sewage treatment plant to the granular sludge reactor (3), and control the sludge concentration at 2000 mg / L - 8000 mg / L; 2) Start the first inlet pump (3.2), and pump the influent of hardly biodegradable carbon source, ammonia nitrogen and phosphate with a volume of V1 into the granular sludge reactor (3), and control V1 to be 40% - 80% of the effective volume V of the reactor; 3) Control the static time to be greater than 1 h, start the first drain pump (3.5), and pump the supernatant containing phosphate and ammonia nitrogen with a volume of V2 into the phosphorus and ammonia nitrogen outlet water tank (5), and control V2 to be 30% - 90% of V1; 4) Start the first stirrer (3.1), and stop stirring when the sewage and sludge are fully mixed; 5) Control the sedimentation time to be less than 20 min, start the first sludge discharge pump (3.4), and discharge the fermentative denitrifying phosphorus-removing granular sludge with a volume of V3 into the PHAs recovery tank (4), and V3 is the difference between V1 and V2; 6) Start the second inlet pump (3.3), and pump the influent of nitrate nitrogen with a volume of V4 into the granular sludge reactor (3), and control the molar ratio of nitrate nitrogen to phosphate in the granular sludge reactor (3) to be greater than 1.5; 7) Start the first stirrer (3.1), and stop stirring when the nitrate nitrogen concentration drops to 0 mg / L; 8) Control the sedimentation time to be greater than 10 min, start the first drain pump (3.5), and pump the supernatant with a volume of V4 into the phosphorus and ammonia nitrogen outlet water tank (5); 9) Repeat steps 2 - 8 until the proportion of granular sludge with a particle size greater than 200 μm in the mixed sludge is greater than 30%, and control the sedimentation time in step 5 to be less than 10 min; 10) Repeat steps 2 - 8 until the proportion of granular sludge with a particle size greater than 200 μm in the mixed sludge is greater than 50%, the molar ratio of phosphate to ammonia nitrogen in the anaerobic end granular sludge reactor (3) is greater than 1.0, and at the same time the pH value in the anoxic end granular sludge reactor (3) is greater than 8.5, indicating that the cultivation of fermentative denitrifying phosphorus-removing granular sludge is finally achieved; II. Struvite recovery: 1) Start the third inlet pump (7.1), and pump the influent of ammonia nitrogen and phosphate with a volume of V5 into the struvite reactor (7), and V5 is the sum of V2 and V4; 2) Start the fourth inlet pump (7.2), and pump the magnesium solution into the struvite reactor (7), and control the molar ratio of magnesium ions to phosphate ions to be 1.0; 3) Start the second stirrer (7.3) and the third stirrer (7.4), and stop stirring when the phosphate concentration drops to 0 mg / L; 4) Control the sedimentation time to be greater than 10 min, start the second drain pump (7.7), and discharge the effluent into the outlet water tank (9); 5) Start the second sludge discharge pump (7.6), and discharge the struvite precipitate into the phosphorus recovery tank (8), and finally recover the phosphorus resources in the form of struvite.

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