Phosphorus release device for excess sludge

Abstract

The utility model relates to the technical field of sludge treatment, in particular to a phosphorus release device for excess sludge. The residual sludge phosphorus release device comprises two core units, namely a sludge concentration unit and a sludge disintegration unit, and the overall structure is simplified; 10%-20% of concentrated sludge which is subjected to concentration treatment by the sludge concentration unit is subjected to alkali addition and disintegration in the sludge disintegration unit, COD (carbon source) released by disintegration is circulated to the sludge concentration unit to serve as a carbon source of phosphorus-accumulating microorganisms (phosphorus-accumulating bacteria) in total residual sludge, and anaerobic phosphorus release occurs in an anaerobic environment of the sludge concentration unit; an additional carbon source is not needed, and low-cost and efficient phosphorus release of the full-amount excess sludge is realized through combination of alkali release of a small amount of concentrated sludge and anaerobic biological phosphorus release of the full-amount excess sludge.

Description

TECHNICAL FIELD

[0001] The utility model relates to a kind of phosphorus release device of residual sludge. BACKGROUND

[0002] To realize the effective recovery of phosphorus in sludge, the phosphorus in sludge (solid phase) needs to be released into the liquid phase as much as possible, and the efficient release of phosphorus is the key step of phosphorus recovery.

[0003] The existing phosphorus release technology mainly includes:

[0004] ①Physical cracking method: using thermal hydrolysis, ultrasonic wave, mechanical ball milling and other methods to break the microbial cells in sludge, and release the intracellular and extracellular phosphorus-containing substances into the liquid phase. Sludge thermal hydrolysis needs to be carried out under high temperature and high pressure conditions (150-190℃, 0.7-2.6MPa), and is usually used as a pretreatment process combined with anaerobic digestion process. The equipment is complex, the operation and maintenance are difficult, the investment and energy consumption are high, and the treatment of the malodorous gas produced is difficult. At present, there are only a few engineering application cases. Although ultrasonic wave cracking has high efficiency and short reaction time (10-60min) and simple equipment, it is still in the laboratory research stage due to high power consumption, and the actual engineering application needs to overcome the defect of high power consumption.

[0005] ②Chemical cracking method: adding acid, alkali or H2O2, ozone and other chemical reagents to residual sludge to destroy the microbial cell structure and release the intracellular and extracellular phosphorus-containing substances into the liquid phase. The acid-alkali cracking method has the characteristics of simple process and mature technology, but the existing full-scale acid-alkali cracking or H2O2, ozone oxidation method has high chemical consumption cost, and it is still difficult to realize engineering application.

[0006] ③Biological phosphorus release method: releasing phosphorus through anaerobic digestion or enzyme-promoted biological phosphorus release. The enzyme-promoted biological phosphorus release technology has high reagent cost and is currently in the laboratory research stage. Anaerobic digestion is the most commonly used sludge disposal technology in engineering application, which has the advantages of mature technology and low operating cost, but the method has slow phosphorus release rate, long reaction time (20-30d of anaerobic digestion of sludge is required), large reaction device volume and high construction investment. If the anaerobic phosphorus release rate needs to be increased and the anaerobic phosphorus release time needs to be shortened, a sufficient amount of carbon source is required, but the available carbon source in the residual sludge discharged from the biochemical system has been consumed in the front-end biochemical system, and a large amount of external carbon source is required to meet the requirements.

[0007] ④ Sludge incineration-wet leaching process: sludge is dewatered, dried and incinerated into ash, and then phosphorus is leached by acid and alkali. The phosphorus in sludge incineration ash mainly exists in the form of combination with Ca, Mg, Fe, Al and other metals in ash, which cannot be absorbed and utilized by plants, and the heavy metal substances in sludge are still retained in the ash after incineration. The phosphorus in sludge ash needs to be separated from the heavy metals, and the phosphorus needs to be converted into a form that can be used by plants. The process flow is complex, and the cost of phosphorus recovery is high.

[0008] ⑤ Combined cracking method: combined technologies such as thermal hydrolysis-acid leaching, acidification-microwave radiation, ultrasonic wave-ozone, ultrasonic wave-alkali dissolution are used to destroy the microbial cell structure in sludge and release phosphorus-containing substances into liquid phase. Compared with single technology, combined technology can combine the advantages of various technologies, and is the development trend of the technical field.

[0009] In actual application, due to the complexity and high price of sludge phosphorus release technology and equipment system, most of the sludge is directly landfilled or incinerated after concentration and dewatering treatment, and the phosphorus in the sludge is not recycled and utilized.

[0010] In summary, there is an urgent need for a remaining sludge phosphorus release device with simple structure and high efficiency to solve the problems in the prior art. Utility model content

[0011] The utility model aims at providing a remaining sludge phosphorus release device with simple structure and high efficiency, and the specific technical scheme is as follows:

[0012] A remaining sludge phosphorus release device comprises a sludge concentration unit and a sludge cracking unit.

[0013] The sludge concentration unit is used for concentrating the remaining sludge, and is provided with a remaining sludge feeding port, a concentrated sludge discharge port and a supernatant discharge port.

[0014] The feeding port of the sludge cracking unit is communicated with the concentrated sludge discharge port of the sludge concentration unit through a first discharge pipe for conveying part of the concentrated sludge discharged from the concentrated sludge discharge port to the sludge cracking unit.

[0015] The residual sludge phosphorus releasing device of the utility model includes sludge concentration unit and sludge breaking unit, the overall structure is simple, 10%-20% of the concentrated sludge after the concentration treatment of sludge concentration unit is broken down in the sludge breaking unit by adding alkali, and the COD (carbon source) released by the breaking is recycled to the sludge concentration unit as the carbon source of the phosphorus accumulating microorganism (polyphosphorus bacteria) in the full amount of residual sludge, and the anaerobic phosphorus release occurs in the anaerobic environment of the sludge concentration unit, so that the carbon source is not needed to be added externally, the combination of a small amount of concentrated sludge alkali hydrolysis phosphorus release and the full amount of residual sludge anaerobic biological phosphorus release realizes the low-cost and high-efficiency phosphorus release of the full amount of residual sludge.

[0016] Preferably, the sludge concentration unit is a gravity concentration tank.

[0017] Preferably, the sludge breaking unit includes a shell, a stirring assembly, a sludge inlet pipe and a sludge outlet pipe; the shell includes a body with a containing cavity, the sludge inlet pipe and the sludge outlet pipe are both arranged on the body and both communicate with the containing cavity; the body is provided with a dosing pipe communicating with the containing cavity; the stirring assembly includes a driving power source, a stirring shaft and stirring blades, the driving power source is arranged on the shell; the connecting end of the stirring shaft is connected with the output end of the driving power source, the free end of the stirring shaft is arranged in the containing cavity and is provided with the stirring blades thereon; the first discharge pipe communicates with the sludge inlet pipe, and the sludge outlet pipe communicates with the first connecting pipe. The sludge breaking unit of the utility model includes a shell, a stirring assembly, a sludge inlet pipe and a sludge outlet pipe, the overall structure is simple, and the dosing pipe is used for adding medicine, and the stirring blades are designed to realize the combination of alkali hydrolysis and mechanical breaking, the cells of the microorganisms in the sludge are broken under the strong alkaline environment and the collision and extrusion of mechanical breaking, and the sludge breaking efficiency is higher and the comprehensive cost is lower.

[0018] Preferably, a plurality of layers of the stirring blades are arranged on the stirring shaft in the axial direction. The stirring assembly provides sufficient upward thrust for the sludge in the containing cavity, and further promotes the sludge breaking.

[0019] Preferably, a pH controller is further included, the body is provided with a measuring hole communicating with the containing cavity, the pH controller is arranged at the measuring hole for measuring the pH value of the sludge; the pH controller is connected with an external PLC control system, and the pH controller measures the pH value of the sludge through a measuring electrode; the measuring electrode is arranged at the measuring hole and the outer side of the measuring electrode is provided with a protective net.

[0020] Preferably, the inner wall of the accommodating cavity is further provided with a plurality of protrusions towards the center of the accommodating cavity; the protrusions are semispherical protrusions with a radius of 40-80mm; the plurality of protrusions are uniformly distributed on the inner wall of the accommodating cavity. The design of the protrusions in the utility model can strengthen the turbulence degree of the fluid in the accommodating cavity, further increase the collision frequency and intensity of the sludge particles and the ball mill balls in the accommodating cavity.

[0021] Preferably, the body is further provided with a stench collecting pipe for collecting the stench generated in the accommodating cavity; the shell further comprises an opening in communication with the accommodating cavity, a detachable cover plate is arranged at the opening, and the driving power source, the dosing pipe, the pH controller and the stench collecting pipe are arranged on the detachable cover plate. The design of the detachable cover plate facilitates the installation and disassembly of the device and the replacement of the components, and meets the processing requirements of different residual sludge.

[0022] Preferably, the utility model further comprises a sludge dewatering unit, the sludge dewatering unit is provided with a dewatering feed inlet, a dry sludge output port and a sludge dewatering liquid discharge port; the dewatering feed inlet is in communication with the concentrated sludge discharge port of the sludge concentration unit through a second discharge pipe, and is used for feeding another part of sludge into the sludge dewatering unit for dewatering treatment; the dry sludge output port is used for discharging dry sludge after dewatering treatment; and the sludge dewatering liquid discharge port is used for discharging sludge dewatering liquid after dewatering treatment. The design of the sludge dewatering unit facilitates the dewatering treatment of most of the sludge after concentration treatment and the delivery of dry sludge, and realizes the processing of residual sludge.

[0023] Preferably, the utility model further comprises a third connecting pipe, and the first discharge pipe and the second discharge pipe are both in communication with the concentrated sludge discharge port of the sludge concentration unit through the third connecting pipe. The three-way pipe design is adopted, the concentrated sludge discharge port is in communication with the first discharge pipe and the second discharge pipe through the third connecting pipe, and the valve is convenient to set for adjusting the amount of concentrated sludge in the two groups of pipes.

[0024] In addition to the purposes, features and advantages described above, the utility model has other purposes, features and advantages. The utility model will be further described in detail below with reference to the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0025] The drawings constituting a part of the application are used to provide further understanding of the utility model, and the schematic embodiments of the utility model and the description thereof are used to explain the utility model, and do not constitute improper limitation on the utility model. In the drawings:

[0026] Figure 1 It is the structure schematic view of the residual sludge phosphorus release device in the preferred embodiment of the utility model;

[0027] Figure 2 It is Figure 1Structure diagram of sludge breaking unit;

[0028] Wherein, 1, sludge concentration unit, 1.1, residual sludge feeding port, 1.2, concentrated sludge discharge port, 1.3, supernatant discharge port;2, sludge breaking unit, 2.1, shell, 2.1.1, containing cavity, 2.1.2, body, 2.1.3, protrusion, 2.1.4, detachable cover plate, 2.2, stirring assembly, 2.2.1, driving power source, 2.2.2, stirring shaft, 2.2.3, stirring blade, 2.3, sludge inlet pipe, 2.4, sludge outlet pipe, 2.5, dosing pipe, 2.6, pH controller, 2.6.1, measuring electrode, 2.7, odor collection pipe;3, sludge dewatering unit, 3.1, dewatering feeding port, 3.2, dry sludge output port, 3.3, sludge dewatering liquid discharge port;4, residual sludge feeding pipe;5, dry sludge conveying pipe;6, first discharge pipe, 7, second discharge pipe, 8, third discharge pipe, 9, first connecting pipe, 10, second connecting pipe, 11, third connecting pipe;L1, first flow meter, L2, second flow meter, L3, third flow meter, F1, first electric valve, F2, second electric valve, B1, booster pump. DETAILED DESCRIPTION

[0029] The embodiments of the present application will be described in detail below with reference to the accompanying drawings, but the present application can be implemented in various different ways as limited and covered by the claims.

[0030] Embodiment:

[0031] Reference Figure 1 A residual sludge phosphorus release device, comprising a sludge concentration unit 1, a sludge breaking unit 2, a sludge dewatering unit 3, a residual sludge feeding pipe 4 and a dry sludge conveying pipe 5, details as follows:

[0032] The sludge concentration unit 1 is used for concentrating residual sludge, and is provided with a residual sludge feeding port 1.1, a concentrated sludge discharge port 1.2 and a supernatant discharge port 1.3;the residual sludge feeding port 1.1 is communicated with a residual material conveying device through the residual sludge feeding pipe 4 for conveying residual sludge to the sludge concentration unit, and the residual sludge feeding pipe 4 is provided with a first flow meter L1. In the embodiment, the sludge concentration unit 1 is a circular gravity concentration tank of prior art, and the tank body is made of reinforced concrete or steel anticorrosive equipment;the concentration time of sludge in the tank (calculated by hydraulic retention time) is 14-24h. The residual sludge feeding port 1.1 and the supernatant discharge port 1.3 are arranged at the upper part of the sludge concentration unit, and the concentrated sludge discharge port 1.2 is arranged at the bottom of the sludge concentration unit.

[0033] In detail Figure 1, the concentrated sludge discharged from the concentrated sludge discharge outlet 1.2 after being concentrated in the sludge concentration unit 1 is output to the sludge disintegration unit 2 through the first discharge pipe 6 after passing through the third connecting pipe 11, and another part of the concentrated sludge discharged from the concentrated sludge discharge outlet 1.2 after being concentrated in the sludge concentration unit 1 is output to the sludge dewatering unit 3 through the second discharge pipe 7 after passing through the third connecting pipe 11, and the supernatant after the sludge is concentrated is discharged from the supernatant discharge outlet 1.3 and then transported to the phosphorus recovery device through the third discharge pipe 8; the sludge subjected to disintegration treatment in the sludge disintegration unit 2 is lifted by the lifting pump B1 and then transported to the residual sludge feeding pipe 4 through the first connecting pipe 9 to be mixed with the residual sludge; the dry sludge subjected to dewatering treatment in the sludge dewatering unit 3 is output through the dry sludge conveying pipe 5, and the sludge dewatering liquid subjected to dewatering treatment in the sludge dewatering unit 3 is transported to the third discharge pipe 8 through the second connecting pipe 10 and then enters the phosphorus recovery device. In this embodiment, a third connecting pipe 11 is further included, and the first discharge pipe 6 and the second discharge pipe 7 are both in communication with the concentrated sludge discharge outlet at the bottom of the sludge concentration unit 1 through the third connecting pipe 11.

[0034] The first discharge pipe 6 is provided with a first electric valve F1 and a second flow meter L2, and the second discharge pipe 7 is provided with a second electric valve F2 and a third flow meter L3.

[0035] The structure of the sludge disintegration unit 2 is shown in detail in Figure 1 and Figure 2 , including a shell 2.1, a stirring assembly 2.2, a sludge inlet pipe 2.3, and a sludge outlet pipe 2.4. The shell 2.1 includes a body 2.1.2 with a containing cavity 2.1.1, and the body 2.1.2 is a cylindrical shell with an opening at the upper end, and a detachable cover plate 2.1.4 is arranged at the opening. The sludge inlet pipe 2.3 and the sludge outlet pipe 2.4 are both arranged on the body 2.1.2 and are in communication with the containing cavity 2.1.1. In this embodiment, the sludge inlet pipe 2.3 is in communication with the containing cavity 2.1.1 and is located at the lower part of the containing cavity 2.1.1, and the sludge outlet pipe 2.4 is in communication with the containing cavity 2.1.1 and is located at the upper part of the containing cavity 2.1.1, i.e., the sludge enters from the lower part of the containing cavity and is discharged from the upper part of the containing cavity. The body 2.1.2 is provided with a dosing pipe 2.5 in communication with the containing cavity 2.1.1, and the dosing pipe 2.5 is in communication with an external dosing device. A flow regulating switch is arranged on the pipeline connecting the dosing pipe 2.5 and the dosing device to adjust the amount of dosing in the dosing pipe 2.5. The stirring assembly 2.2 includes a driving power source 2.2.1, a stirring shaft 2.2.2, and stirring blades 2.2.3, and the driving power source 2.2.1 is arranged on the shell 2.1 Figure 2The driving power source is a driving motor, which is arranged on the detachable cover plate 2.1.4, and the whole stirring assembly can be taken out of the containing cavity through the detachable cover plate; the connecting end of the stirring shaft 2.2.2 is connected with the output end of the driving power source 2.2.1, and the free end of the stirring shaft 2.2.2 is arranged in the containing cavity 2.1.1 and is provided with the stirring blades 2.2.3. In the embodiment, two layers of the stirring blades 2.2.3 are arranged on the stirring shaft 2.2.2 along the axial direction of the stirring shaft, one layer of the stirring blades is arranged at the position close to the end of the free end of the stirring shaft, and the other layer of the stirring blades is arranged at the middle position of the stirring shaft. The stirring shaft 2.2.2 is located on the axis of the containing cavity. The multiple layers of the stirring blades 2.2.3 rotate to generate upward thrust on the fluid. In addition, ball milling balls can be arranged in the sludge breaking unit 2, preferably a plurality of ball milling balls with a diameter of 3-4 mm; the effective volume of the ball milling balls filled in the containing cavity is 10%-20% (further preferably 15%). Further preferably, the ball milling balls in the embodiment are made of 30% glass fiber reinforced injection molding grade PA66 material (density 1.15-1.35 g / cm 3 ) with good wear resistance and light weight, and compared with high-density ball milling balls, the ball milling balls are easier to realize fluidization and avoid deposition at the bottom of the containing cavity.

[0036] The embodiment also comprises a pH controller 2.6, the body 2.1.2 is provided with a measuring hole communicating with the containing cavity 2.1.1, and the pH controller is arranged at the measuring hole and used for measuring the pH value of the sludge. The pH controller is connected with an external PLC control system, and the pH controller measures the pH value of the sludge through a measuring electrode 2.6.1; the measuring electrode is arranged at the measuring hole, and the outer side of the measuring electrode is provided with a protective net. The measuring electrode can be deep into the liquid surface below the containing cavity. The design of the protective net can prevent the measuring electrode from being damaged by the collision of the ball milling balls during operation, and prolong the service life of the measuring electrode. In the embodiment, the pH control range in the sludge breaking unit is 10.8-11.5, and the reaction time of the sludge breaking is 40-120 min. Further preferably, the sludge outlet pipe is provided with a valve and a filter screen (not shown), the mesh size of the filter screen is smaller than the size of the ball milling balls, so as to prevent the ball milling balls from flowing out of the sludge outlet pipe. In the embodiment, the valve and the filter screen can also be arranged on the sludge inlet pipe.

[0037] The inner wall of the accommodating cavity 2.1.1 in the embodiment is also provided with a plurality of protrusions 2.1.3 towards the center of the accommodating cavity. Preferably, the protrusions 2.1.3 are semispherical protrusions with a radius of 40-80 mm; the plurality of protrusions 2.1.3 are uniformly distributed on the inner wall of the accommodating cavity. Further preferably, a plurality of semispherical protrusions with a radius of 50 mm are arranged on the vertical inner side wall of the accommodating cavity; the semispherical protrusions have the same radius and are uniformly distributed on the vertical inner side wall of the accommodating cavity; the distance between the edges of two adjacent protrusions is 1-2 times (preferably 1.5 times in the embodiment) the diameter of the protrusions. The semispherical protrusions arranged on the inner side wall of the accommodating cavity in the embodiment can avoid the regular circumferential movement of the ball mill balls along the tank wall, enhance the turbulence intensity in the shell, increase the collision probability of the ball mill balls, make the microorganisms in the sludge collide and extrude at a higher frequency, and improve the disintegration efficiency.

[0038] In the embodiment, the body 2.1.2 is also provided with a foul gas collecting pipe 2.7 for collecting the foul gas generated in the accommodating cavity. The foul gas collecting pipe and the dosing pipe both pass through the detachable cover plate 2.1.4.

[0039] In the embodiment, the sludge disintegration unit 2 is made of carbon steel anticorrosive material, sodium hydroxide is used for disintegrating the sludge, the pH control range in the sludge disintegration device is 10.8-11, and the reaction time for sludge disintegration is 40-60 min.

[0040] In the embodiment, the sludge dewatering unit 3 adopts an existing horizontal spiral centrifugal dewatering complete equipment; the sludge dewatering unit 3 is provided with a dewatering feed inlet 3.1, a dry sludge output port 3.2 and a sludge dewatering liquid discharge port 3.3; the dewatering feed inlet 3.1 is communicated with the concentrated sludge discharge port of the sludge concentration unit 1 through the second discharge pipe 7, and is used for feeding another part of the sludge to the sludge dewatering unit for dewatering treatment; the dry sludge output port 3.2 is used for discharging the dry sludge after dewatering treatment; and the sludge dewatering liquid discharge port 3.3 is used for discharging the sludge dewatering liquid after dewatering treatment. In the embodiment, no lime, iron salt or aluminum salt reagent is added during the sludge dewatering process, only a small amount of polyacrylamide reagent is added as needed, and the dewatered sludge discharged after the sludge dewatering is transported and disposed.

[0041] The controller is composed of a cable and an electric control cabinet containing a programmable logic controller (PLC). The first flow meter L1, the first electric valve F1, the second electric valve F2, the second flow meter L2, the third flow meter L3, the booster pump B1, the driving power source 2.2.1, and the pipeline connected with the dosing pipe and the dosing device are connected with the controller. The cable and the electric control cabinet containing the programmable logic controller (PLC) are both mature existing devices, which can supply power to the flow meter and communicate with the flow meter. The PLC controls the operation of the external dosing device and other devices according to the data detected by the flow meter and the preset control logic. The control logic of the present embodiment is as follows: on the one hand, the pH controller 2.6 of the sludge disintegration unit 2 is connected with the controller, and the pH value of the sludge in the sludge disintegration unit is determined in real time by measuring the electrode 2.6.1. The PLC in the controller controls the external dosing system to add alkali into the sludge disintegration unit according to the preset target pH value (the target pH value used in the present embodiment is 10.8-11.5). When the real-time measured pH value is consistent with or greater than the preset target pH value, the dosing system stops adding alkali into the sludge disintegration unit. When the real-time measured pH value is lower than the preset target pH value, the dosing system adds alkali into the sludge disintegration unit. On the other hand, the electric control cabinet containing the programmable logic controller (PLC) in the controller controls the first electric valve F1 and the second electric valve F2 according to the real-time monitored sludge flow of the second flow meter L2 on the first discharge pipe 6 connected with the sludge disintegration unit 2 and the third flow meter L3 on the second discharge pipe 7 connected with the sludge dewatering unit 3, and adjusts the sludge flow entering the sludge disintegration unit. In the present embodiment, the sludge flow (Q 破解 ) entering the sludge disintegration unit and the sludge flow (Q 脱水 ) entering the sludge dewatering unit are controlled according to the following method: Q 破解 / (Q 破解 +Q 脱水 ) = 0.1-0.2. The booster pump B1 and the stirring assembly 2.2 are linked with the second flow meter L2. When the flow detected by the second flow meter L2 is greater than 0, the booster pump B1 and the stirring assembly 2.2 are started. When the flow detected by the second flow meter L2 is 0, the booster pump B1 and the stirring assembly 2.2 are stopped.

[0042] The specific working process of the residual sludge phosphorus release device of the present embodiment is as follows:

[0043] The residual sludge (Q 剩余 with a water content of 99.2%) discharged from the sewage treatment biochemical system is mixed with the disintegrated sludge (Q 破解后) into the sludge concentration unit 1, the remaining sludge rich in phosphorus is concentrated in the sludge concentration unit 1 under the action of the carbon source provided by the broken sludge, and the anaerobic biological phosphorus release effect occurs at the same time, the phosphorus in the solid phase is released into the liquid phase, and the low-phosphorus sludge after concentration and biological phosphorus release is discharged from the bottom of the gravity concentration tank Concentration tank, a part of the concentrated sludge (Q 破解 ) into the sludge disintegration unit 2 through the first discharge pipe 6 to disintegrate the sludge, and the disintegrated sludge (Q 破解后 ) returns to the remaining sludge feeding pipe 4 of the sludge concentration tank; another part of the concentrated sludge (Q 脱水 ) is discharged into the sludge dewatering unit for dewatering treatment, and in this embodiment, the flow or mass ratio of the total amount of sludge into the sludge disintegration unit and the concentrated sludge after concentration is Q 破解 : (Q 破解 + Q 脱水 ) = 0.2; the high-concentration phosphorus supernatant produced by the sludge concentration unit 1 is discharged into another set of phosphorus recovery device to recover phosphorus; the sludge dewatering liquid produced by the sludge dewatering unit 3 is mixed with the supernatant of the sludge concentration tank through the second connecting pipe 10, and then discharged into the phosphorus recovery device together to recover phosphorus, and the dry sludge is transported through the dry sludge conveying pipe 5. Transport and disposal.

[0044] In this embodiment, after the sludge is disintegrated by alkali, COD (carbon source), ammonia nitrogen, organic nitrogen, orthophosphate, organic phosphorus and other substances are released into the aqueous phase and converted into disintegrated sludge (Q 破解后 ), the main component test data of the sludge before concentration (Q 剩余 ), after disintegration (Q 破解后 ) are shown in Table 1, the mass of the disintegrated sludge (Q 破解后 ) is equal to the sum of the mass of the concentrated sludge (Q 破解 ) plus the mass of the alkali agent added during disintegration, and the disintegrated sludge (Q 破解后 ) is discharged into the water inlet of the gravity concentration tank. The sludge disintegration step in this scheme achieves four technical effects: ① The sludge disintegration releases the phosphorus in the sludge, releasing orthophosphate from the solid phase to the liquid phase, creating conditions for the subsequent phosphorus recovery unit to recover phosphorus; ② The high-concentration COD (carbon source) released by the sludge disintegration returns to the sludge concentration tank, serving as a carbon source for the anaerobic biological phosphorus release of the remaining sludge, eliminating the need for external carbon source, achieving "waste treatment with waste", and saving the cost of sludge phosphorus release; ③ The sludge disintegration releases ammonia nitrogen, reducing the amount of ammonium salt (such as ammonium chloride) added to the subsequent phosphorus recovery unit to recover struvite, further saving the cost of phosphorus recovery; ④ The sludge after disintegration can improve the dewatering performance, reduce the amount of sludge dewatering agent in the subsequent sludge dewatering unit, and is conducive to improving the treatment efficiency of the subsequent sludge dewatering unit and reducing the cost of sludge dewatering.

[0045] Table 1 Main components before and after sludge concentration

[0046]

[0047] Note: The sludge (Q) before thickening in the table. 剩余 The concentration of excess sludge entering the sludge thickening unit (MLSS = 8 g / L) and the sludge concentration after thickening and cracking (Q) 破解后 The sludge concentration MLSS was 20 g / L in this embodiment. After sludge thickening and cracking, (Q) 破解后 The volume of ) is only the volume of excess sludge Q entering the sludge thickening unit. 剩余 Approximately 8%. The composition data of the sludge were obtained by centrifuging the sludge and taking the supernatant.

[0048] The unconcentrated sludge (Q_residual) and the sludge after disintegration (Q_disintegrated) are mixed and then enter sludge thickening unit 1 (i.e., gravity thickening tank). Compared with conventional gravity thickening processes, this embodiment achieves the following technical effects in addition to physical sludge thickening in the gravity thickening tank: ① Phosphorus-rich microorganisms (such as polyphosphate-accumulating bacteria) in the unconcentrated sludge release intracellular phosphorus into the water (as orthophosphate, PO4) under the action of COD (carbon source) provided by the disintegrated sludge and in the anaerobic conditions of the sludge thickening tank. 3- (existing in the form of phosphate), achieving anaerobic biological phosphorus release of all excess sludge, and reducing orthophosphate (PO4) in the supernatant of the thickener. 3- The concentration of phosphorus (calculated as phosphorus) can reach 50-60 mg / L, creating conditions for subsequent phosphorus recovery. ② The organic nitrogen and organic phosphorus contained in the sludge are converted into ammonia nitrogen and orthophosphate (PO4) under the anaerobic environment of the sludge thickening tank and the action of anaerobic microorganisms in the excess sludge. 3- The conversion of organic nitrogen to ammonia nitrogen can save on the amount of reagents needed for ammonia nitrogen recovery in subsequent phosphorus recovery units. The conversion of organic phosphorus to orthophosphate can further improve phosphorus recovery efficiency (organic phosphorus cannot be recovered through struvite crystallization). Table 2 shows the test data for the main components of the sludge before thickening, the liquid at the inlet of the sludge thickening tank (i.e., the liquid in the residual sludge feed pipe 4 at the inlet of the sludge thickening unit), and the supernatant effluent from the sludge thickening unit. This embodiment shows a significant effect on phosphorus release from sludge, and most of the phosphorus exists in the form of orthophosphate, which can be recovered by subsequent phosphorus recovery units.

[0049] Table 2. Main components of the supernatant effluent from the sludge thickening unit before thickening, at the inlet of the sludge thickening tank, and at the outlet of the sludge thickening unit.

[0050]

[0051] Note: The table shows the sludge concentration before (Q) 剩余MLSS = 8 g / L, the data before sludge concentration is the data measured by centrifuging the sludge to obtain the supernatant; the sludge concentration of the mixed liquor at the water inlet of the sludge concentration unit is about 8.8 g / L. In this embodiment, the volume of the concentrated sludge after concentration is 40% of the volume of the sludge before concentration (Q 剩余 ), the proportion of the concentrated sludge (Q 破解 ) entering the sludge disintegration unit in the total amount of the concentrated sludge (Q 破解 + Q 脱水 ) is 20%, the medicament NaOH added in the sludge disintegration unit is added in solid form, the density of the disintegrated sludge is similar to the density of the sludge before disintegration (Q 破解 ), the volume of the disintegrated sludge (Q 破解后 ) accounts for 8% of the volume of the sludge before concentration (Q 剩余 ); the composition of the mixed liquor at the water inlet of the sludge concentration unit is measured by centrifuging the mixed liquor to obtain the supernatant.

[0052] The technical scheme of the present embodiment has the following effects:

[0053] ①, the existing sludge disintegration phosphorus release technology all adopts disintegration of the whole amount of residual sludge, in the present embodiment, only 10% to 20% of the concentrated sludge needs to be disintegrated by adding alkali, and the COD (carbon source) released by disintegration is used as the carbon source of the phosphorus accumulating microorganisms (polyphosphorus bacteria) in the whole amount of residual sludge entering the concentration tank, and anaerobic phosphorus release occurs in the anaerobic environment of the sludge concentration tank, without the need for external carbon source, the new scheme of a small amount of concentrated sludge alkali disintegration phosphorus release + whole amount of residual sludge anaerobic biological phosphorus release realizes low-cost and high-efficiency phosphorus release of the whole amount of residual sludge. In the present embodiment, the equipment investment and operation cost (consumption of medicaments and power consumption) of the sludge disintegration unit is only equivalent to 10% to 20% of the existing whole amount of sludge alkali disintegration phosphorus release process, and the equipment area can also be saved; the addition of carbon source in the disintegrated sludge can shorten the anaerobic biological phosphorus release time of the sludge in the gravity concentration tank to 6h, which is only 1 / 80 of the time required by the traditional sludge anaerobic digestion process (anaerobic digestion time of 20-30d), greatly reducing the equipment investment and operation cost of sludge phosphorus release and phosphorus recovery.

[0054] ②, the existing physical disintegration phosphorus release (ultrasonic, thermal hydrolysis, mechanical ball milling), chemical disintegration phosphorus release (acid, alkali) technology releases a part of phosphorus and nitrogen elements in the liquid phase in the form of organic phosphorus and organic nitrogen, and the organic phosphorus is difficult to recycle; in the present embodiment, the sludge after chemical disintegration is returned to the concentration tank, and the organic phosphorus and organic nitrogen released in the disintegration process are converted into orthophosphate and ammonia nitrogen which can be recycled by the subsequent phosphorus recovery unit under the action of the anaerobic environment in the concentration tank and the anaerobic bacteria in the residual sludge, which can further improve the phosphorus recovery rate and reduce the medicament cost of adding ammonia nitrogen in the phosphorus recovery unit.

[0055] ③、At present, most of the domestic urban sewage treatment plants adopt the technical route of sludge gravity concentration + sludge dewatering disposal for the residual sludge, and have built sludge concentration tanks and sludge dewatering facilities. In the present embodiment, the gravity concentration tank adopts the existing conventional gravity concentration tank. When it is necessary to recover phosphorus from the residual sludge of the built sewage treatment plant, only the sludge disintegration unit (only 10% to 20% of the total amount of concentrated sludge needs to be disintegrated, and the full amount of concentrated sludge does not need to be disintegrated), the sludge phosphorus recovery device, the control system, and the corresponding modification of the pipeline need to be added, so that the sludge phosphorus resource recovery of the existing sewage treatment plant can be economically and conveniently realized.

[0056] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A residual sludge phosphorus releasing device, characterized by, The sludge concentration unit (1) and the sludge disintegration unit (2) are included. The sludge concentration unit (1) is used for concentration treatment of residual sludge, and is provided with a residual sludge feeding port (1.1), a concentrated sludge discharge port (1.2) and a supernatant discharge port (1.3). The residual sludge feeding port (1.1) is communicated with a residual material conveying device for conveying residual sludge to the sludge concentration unit. The feeding port of the sludge disintegration unit (2) is communicated with the concentrated sludge discharge port (1.2) of the sludge concentration unit (1) through a first discharge pipe (6) for conveying part of the concentrated sludge discharged from the concentrated sludge discharge port (1.2) to the sludge disintegration unit. The discharge port of the sludge disintegration unit (2) is communicated with the sludge concentration unit (1) through a first connecting pipe (9) for circulating the disintegration-treated sludge to the sludge concentration unit (1).

2. The apparatus for releasing phosphorus from excess sludge according to claim 1, wherein The sludge concentration unit (1) is a gravity concentration tank.

3. The apparatus for releasing phosphorus from excess sludge according to claim 1 or 2, characterized by, The sludge disintegration unit (2) includes a shell (2.1), a stirring assembly (2.2), a sludge inlet pipe (2.3) and a sludge outlet pipe (2.4). The shell (2.1) includes a body (2.1.2) with a containing cavity (2.1.1). The sludge inlet pipe (2.3) and the sludge outlet pipe (2.4) are arranged on the body (2.1.2) and communicated with the containing cavity (2.1.1). The body (2.1.2) is provided with a dosing pipe (2.5) communicated with the containing cavity (2.1.1). The stirring assembly (2.2) includes a driving power source (2.2.1), a stirring shaft (2.2.2) and stirring blades (2.2.3). The driving power source (2.2.1) is arranged on the shell (2.1). The connecting end of the stirring shaft (2.2.2) is connected with the output end of the driving power source (2.2.1). The free end of the stirring shaft (2.2.2) is arranged in the containing cavity (2.1.1) and provided with the stirring blades (2.2.3). The first discharge pipe (6) is communicated with the sludge inlet pipe (2.3), and the sludge outlet pipe (2.4) is communicated with the first connecting pipe (9).

4. The apparatus for releasing phosphorus from excess sludge according to claim 3, wherein The stirring shaft (2.2.2) is provided with multiple layers of the stirring blades (2.2.3) along the axial direction thereof.

5. The apparatus for releasing phosphorus from excess sludge according to claim 3, wherein A pH controller (2.6) is further included. The body (2.1.2) is provided with a measuring hole communicated with the containing cavity (2.1.1). The pH controller is arranged at the measuring hole for measuring the pH value of the sludge. The pH controller is connected with an external PLC control system. The pH controller measures the pH value of the sludge through a measuring electrode (2.6.1). The measuring electrode is arranged at the measuring hole and the outer side of the measuring electrode is provided with a protective net.

6. The apparatus for releasing phosphorus from excess sludge according to claim 5, wherein The inner wall of the containing cavity (2.1.1) is further provided with multiple protrusions (2.1.3) towards the center of the containing cavity. The protrusions (2.1.3) are semispherical protrusions with a radius of 40-80 mm. The multiple protrusions (2.1.3) are uniformly distributed on the inner wall of the containing cavity.

7. The apparatus for releasing phosphorus from excess sludge according to claim 6, wherein The body (2.1.2) is further provided with a foul gas collecting pipe (2.7) for collecting the foul gas generated in the containing cavity; the shell (2.1) further comprises an opening in communication with the containing cavity (2.1.1), and a detachable cover plate (2.1.4) is arranged at the opening; the driving power source (2.2.1), the dosing pipe (2.5), the pH controller (2.6) and the foul gas collecting pipe (2.7) are all arranged on the detachable cover plate (2.1.4).

8. The apparatus for releasing phosphorus from excess sludge according to claim 3, wherein Further comprising a sludge dewatering unit (3), which is provided with a dewatering feed inlet (3.1), a dry sludge output port (3.2) and a sludge dewatering liquid discharge port (3.3); The dewatering feed inlet (3.1) is in communication with the concentrated sludge discharge port of the sludge concentration unit (1) through a second discharge pipe (7) for feeding another part of sludge to the sludge dewatering unit for dewatering treatment; the dry sludge output port (3.2) is used for discharging dry sludge after dewatering treatment; and the sludge dewatering liquid discharge port (3.3) is used for discharging sludge dewatering liquid after dewatering treatment.

9. The apparatus for releasing phosphorus from excess sludge according to claim 8, wherein Further comprising a third connecting pipe (11), and the first discharge pipe (6) and the second discharge pipe (7) are both in communication with the concentrated sludge discharge port of the sludge concentration unit (1) through the third connecting pipe (11).

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