Device and method for enhancing nitrogen and phosphorus removal and sludge reduction of sewage through fermentation

Abstract

The invention belongs to the technical field of biological treatment of sewage with few carbon sources, and particularly relates to a device and a method for enhancing nitrogen and phosphorus removal and sludge reduction of sewage by fermentation, the device comprises a mainstream sewage treatment system and a side flow return sludge fermentation system, the mainstream sewage treatment system comprises a sequencing batch reactor of a cyclic activated sludge process (CASS); a partition plate with water passing holes is arranged in the sequencing batch reactor, and the sequencing batch reactor is divided into a premixing area and a main reaction area by the partition plate with the water passing holes; the device has an efficient lateral flow enhancement effect, the lateral flow sludge treatment amount is small (only 3%-20% of lateral flow return sludge is treated), and the treatment time is short (the sludge fermentation time lt; in the fermentation process, chemicals are not required to be added, pH and heating are not required to be controlled, and the main flow nitrogen and phosphorus removal efficiency can be improved, the total nitrogen and total phosphorus of effluent can be reduced and an oligocarbon source (COD / TNlt) can be realized by only relying on anaerobic fermentation of the returned sludge at room temperature; and 8) the nitrogen and phosphorus removal treatment of the urban sewage reaches the standard, and the method has the characteristics of economy and high efficiency.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of oligocarbon source sewage biological treatment, and particularly relates to a device and method for fermentation-enhanced sewage denitrification and phosphorus removal and sludge reduction. BACKGROUND

[0002] Direct discharge of municipal sewage into natural water bodies can induce water eutrophication, leading to water pollution and environmental damage, and therefore needs to be treated for denitrification and phosphorus removal before being discharged. The increasingly stringent sewage discharge standards bring higher treatment difficulty and cost. At the same time, the municipal sewage nutrient salt treatment process often faces the problem of insufficient carbon source, especially in the southern region of China, the low concentration of organic carbon source and the imbalance of C / N ratio in municipal sewage treatment plants are significant, and the traditional sewage treatment process often needs to add commercial carbon source to meet the carbon demand of denitrification and biological phosphorus removal, which greatly increases the cost of sewage treatment, and also increases the production of excess sludge and energy consumption, causing secondary pollution and other problems. The sewage treatment industry urgently needs to develop and apply a green low-carbon sewage treatment process suitable for oligocarbon source water quality to solve the problem of insufficient carbon source in the municipal sewage treatment process.

[0003] Sludge anaerobic fermentation can convert complex organic matter that is difficult for microorganisms to utilize into small molecular carbon components that are easy to utilize, achieving sludge resource utilization; and side-stream fermentation of return sludge can directly improve the utilization rate of carbon source in sewage and reduce the production of excess sludge, compared with exogenous excess sludge fermentation, it can avoid introducing additional nutrient salt load, and the fermentation mixed liquor is fully reused without the need to set up a separation and sedimentation tank, which can simplify the operation and equipment structure.

[0004] The currently reported technologies for enhancing sewage treatment by sludge fermentation mostly focus on continuous flow sewage treatment facilities of AAO, AO and the like, but there are few studies on the application of side-stream sludge fermentation to sewage treatment configurations operated in time sequence (such as SBR, CASS, etc.), and most of the reported side-stream sludge fermentation processes use residual sludge or primary sludge fermentation, but there are few using return sludge; in addition, the reported side-stream sludge fermentation processes often use auxiliary conditions such as alkaline fermentation and medium-temperature (35℃) fermentation, which need additional chemicals and energy consumption, increasing the operation cost and limiting the application prospect of side-stream sludge fermentation technology. Therefore, the present application provides a device and method for fermentation-enhanced sewage denitrification and phosphorus removal and sludge reduction. SUMMARY

[0005] In order to make up for the deficiencies of the prior art and solve at least one technical problem raised in the background.

[0006] The technical scheme adopted by the present application to solve its technical problems is: the device for fermenting, strengthening, denitrifying and dephosphorizing wastewater and reducing sludge amount, comprising a main stream wastewater treatment system and a side stream reflux sludge fermentation system, the main stream wastewater treatment system comprises a sequencing batch reactor of a cyclic activated sludge method (CASS); a partition plate with a water passing hole is arranged in the sequencing batch reactor, and the sequencing batch reactor is divided into a pre-mixing zone and a main reaction zone by the partition plate with the water passing hole; a stirrer is arranged in each of the pre-mixing zone and the main reaction zone, a wastewater inlet pipe, a fermentation mixed liquid inlet pipe and a reflux sludge inlet pipe are arranged in the pre-mixing zone, and the wastewater inlet pipe is connected to a water inlet pump.

[0007] Preferably, a liquid level meter, a water decanter, a water drainage electromagnetic valve, a water outlet pipe, an aeration disc, a residual sludge discharge pipe are arranged in the main reaction zone, a sludge reflux pipeline is arranged outside the sequencing batch reactor, a sludge reflux pump is arranged on the sludge reflux pipeline to drive sludge reflux, and a high water level and a low water level are arranged in the sequencing batch reactor.

[0008] Preferably, the side stream reflux sludge fermentation system comprises a sequencing batch anaerobic fermenter and a fermentation mixed liquid storage tank, a stirrer, a side stream feeding pump, a side stream feeding pipe and a fermentation mixed liquid overflow discharge pipe are arranged in the sequencing batch anaerobic fermenter, one end of the side stream feeding pump is connected to the side stream feeding pipe, and the other end is connected to a branch line of the sludge reflux pipeline.

[0009] Preferably, a fermentation mixed liquid feeding pump is arranged in the fermentation mixed liquid storage tank, and the fermentation mixed liquid feeding pump is connected to the fermentation mixed liquid inlet pipe.

[0010] Preferably, the stirrer comprises a motor, a connecting shaft and a fixed shaft, the motor is arranged outside the sequencing batch reactor and is used to drive the connecting shaft to rotate, the bottom end of the connecting shaft is open, the fixed shaft is arranged in the connecting shaft, a plurality of paddles are arranged on the fixed shaft, and a hydraulic rod is fixedly connected between the top end of the fixed shaft and the inner wall of the connecting shaft.

[0011] Preferably, one connecting ring is fixedly connected to the outer side wall of the fixed shaft, a plurality of rectangular grooves are arranged in the outer side wall of the connecting ring, a circular shaft is fixedly connected to the inner wall of each rectangular groove, the inner wall of the circular shaft is a hollow structure, a rotating shaft is rotatably connected to the inner wall of the circular shaft, the side, away from the fixed shaft, of the rotating shaft is fixedly connected to the paddle, and a rotating assembly for driving the rotating shaft to rotate is arranged on the connecting ring.

[0012] Preferably, the rotating assembly comprises a first connecting plate fixedly connected with the rotating shaft side wall, the outer side wall of the first connecting plate is sealingly and rotatably connected with the inner wall of the circular shaft, the inner wall of the circular shaft is fixedly connected with a second connecting plate, the side of the second connecting plate close to the first connecting plate is sealingly and rotatably connected with the outer side wall of the rotating shaft, the inner part of the connecting ring and the fixed shaft are hollow structures, the outer side wall of the fixed shaft is sealingly and slidingly connected with the inner wall of the connecting shaft, the top surface of the connecting shaft is provided with an air inlet hole, the inner side wall of the connecting ring is provided with a through hole in communication with the inner part of the connecting shaft, the side of the circular shaft away from the paddle is provided with a connecting hole in communication with the inner part of the connecting ring, the outer side wall of the circular shaft is provided with an air outlet hole, the outer side wall of the rotating shaft is sealingly and rotatably connected with the circular shaft, and the circular shaft is provided with a torsional spring (not shown in the figure) for driving the rotating shaft to reset.

[0013] Preferably, the inner wall of the connecting ring is fixedly connected with a group of fixed blocks corresponding to the rotating shaft, the inner part of the fixed block is a hollow structure, the side of the fixed block close to the rotating shaft is slidingly connected with a magnetic rod, the side of the magnetic rod close to the rotating shaft is fixedly connected with a pair of limiting rods, the side of the rotating shaft close to the fixed block is provided with a group of annularly and uniformly distributed clamping grooves, the end of the magnetic rod away from the limiting rod is fixedly connected with a spring between the inner wall of the fixed block, and the inner wall of the fixed block is fixedly connected with an electromagnet repelling the magnetic rod.

[0014] A method for fermenting to strengthen sewage denitrification and sludge reduction, which adopts the device.

[0015] S1: Two working water levels, high water level and low water level, are arranged in the main stream sewage treatment system, and the low water level is the drainage water level; during the anaerobic and aerobic stages, the oligocarbon source (COD / TN=5-8) municipal sewage is slowly added to the premixing area; when the high water level is detected by the liquid level meter, the water inlet pump is closed to complete water inlet, and the stirrer is used to mix the sludge and water in the premixing area and the main reaction area;

[0016] S2: During the drainage standing stage, the drainage electromagnetic valve is opened, and the supernatant in the main reaction area is discharged through the water decanter; when the liquid level is lowered to the low water level, the liquid level meter controls the drainage electromagnetic valve to be closed, and the drainage is stopped;

[0017] S3: The sequencing batch anaerobic fermenter is operated in a way of intermittent sludge inlet and overflow sludge discharge; during the aerobic stage of the main stream sewage treatment system, 3-20% (volume ratio) of the backflow liquid is diverted from the sludge backflow pipeline to the sequencing batch anaerobic fermenter;

[0018] S4: With the liquid level of the sequencing anaerobic fermentor rising, the upper fermentation mixed liquor is discharged by overflow and stored in the fermentation mixed liquor storage tank. In the anaerobic stage of the main stream sewage treatment system, the fermentation mixed liquor feed pump returns all the fermentation mixed liquor to the premixing zone. The sludge fermentation time of the sequencing anaerobic fermentor is 24-96h.

[0019] The beneficial effects of the present application are as follows:

[0020] 1. The device in the present application has high-efficiency side flow enhancement effect, small side flow sludge treatment capacity (only 3-20% of the side flow flow rate is treated) and short treatment time (sludge fermentation time <96h). The fermentation process does not need to add chemicals, control pH and heating. Only by relying on the anaerobic fermentation of the returned sludge at room temperature, the main stream denitrification and phosphorus removal efficiency can be improved, the total nitrogen and total phosphorus in the effluent can be reduced, the denitrification and phosphorus removal treatment of the oligocarbon source (COD / TN <8) municipal sewage can reach the standard, and the device has the characteristics of economy and high efficiency.

[0021] 2. The device in the present application can effectively reduce the residual sludge production by more than 30%, realize sludge resource utilization, reduce the aeration demand, and has the advantages of green and low carbon.

[0022] 3. The sequencing reactor using the cyclic activated sludge method in the present application has similar operation characteristics as the ordinary sequencing reactor, but can improve the water inlet continuity and the nitrogen and phosphorus removal effect. Compared with the continuous flow reactor, the device has the characteristics of no need to set a sludge sedimentation tank, small land occupation area, simple structure and flexible operation.

[0023] 4. The side stream returned sludge fermentation system in the present application directly uses the returned sludge-water mixture for fermentation without sludge concentration and sedimentation. The sludge fermentation liquid is all reused without sludge-water separation, thereby avoiding the setting of a centrifuge and a sedimentation tank, and having the advantages of simple structure and easy realization. The device can effectively reduce the volume of the anaerobic device and save the production and operation cost of the equipment.

[0024] 5. The multi-paddle mixer used in the present application can flexibly and quickly adjust the paddle angle according to the sludge concentration, improve the mixing effect, and ensure the homogeneity of the liquid at different depths to avoid sludge-water separation. BRIEF DESCRIPTION OF DRAWINGS

[0025] The present application will be further described below in combination with the drawings.

[0026] Figure 1 is a structure diagram of the device in the present application;

[0027] Figure 2 is a total nitrogen, total phosphorus and COD concentration change diagram of the water inlet and outlet in Example 1;

[0028] Figure 3is the total nitrogen, total phosphorus and COD concentration change graph of the influent and effluent in Example 2;

[0029] Figure 4 is the total nitrogen, total phosphorus and COD concentration change graph of the influent and effluent under the condition of no side flow fermentation in the application;

[0030] Figure 5 is the structural schematic diagram of the stirring period in the application;

[0031] Figure 6 is the internal structure schematic diagram of the connecting shaft and the fixed shaft in the application;

[0032] Figure 7 is the enlarged view of A of Figure 6 ;

[0033] Figure 8 is the internal structure schematic diagram of the circular shaft in the application;

[0034] Figure 9 is the front view of the rotating shaft in the application;

[0035] Figure 10 is the method flow chart in the application.

[0036] In the figure: 1, pre-mixing area; 1.1, stirrer; 1.2, sewage inlet pipe; 1.3, fermentation mixture inlet pipe; 1.4, backflow sludge inlet pipe; 1.5, partition with water holes; 1.6, water inlet pump; 2, main reaction area; 2.1, liquid level meter; 2.2, high water level; 2.3, low water level; 2.4, water decanter; 2.5, drain electromagnetic valve; 2.6, water outlet pipe; 2.7, aerator; 2.8, aeration disc; 2.9, residual sludge discharge pipe; 2.10, sludge backflow pump; 2.11, sludge backflow pipeline; 3, sequencing batch anaerobic fermenter; 3.1, side flow feeding pump; 3.2, side flow feeding pipe; 3.3, fermentation mixture overflow discharge pipe; 4, fermentation mixture storage tank; 4.1, fermentation mixture feeding pump; 5, connecting shaft; 6, fixed shaft; 7, paddle; 8, hydraulic rod; 9, connecting ring; 10, connecting hole; 11, rectangular groove; 12, circular shaft; 13, rotating shaft; 14, first connecting plate; 15, clamping groove; 16, second connecting plate; 17, connecting block; 18, electromagnet; 19, magnetic rod; 20, through hole; 21, air outlet hole; 22, air inlet hole. DETAILED DESCRIPTION

[0037] In order to make the technical means, creative features, purposes and effects realized by the application easy to understand, the application is further described below in combination with specific embodiments.

[0038] Example 1: as Figure 1 , Figure 2 and Figure 4As shown, the device for fermentation enhanced nitrogen and phosphorus removal from wastewater and sludge reduction according to the embodiment of the application comprises a main stream wastewater treatment system and a side stream return sludge fermentation, and the sequencing batch reactor is a cuboid water tank, which is divided into a pre-mixing area 1 and a main reaction area 2 by a partition plate with a water passing hole, the working volume ratio of the two areas is 1:5-1:10, and a stirrer 1.1 is arranged to realize sludge and water mixing, the pre-mixing area 1 is provided with a wastewater inlet pipe 1.2, a fermentation mixed liquid inlet pipe 1.3 and a return sludge inlet pipe 1.4, and the wastewater inlet pipe 1.2 is connected with a water inlet pump 1.6.

[0039] The main reaction area 2 is provided with a liquid level meter 2.1, a decanter 2.4, a drain electromagnetic valve 2.5, a water outlet pipe 2.6, an aerator 2.7, an aeration disc 2.8 and a residual sludge discharge pipe 2.9, the sequencing batch reactor is externally provided with a sludge return pipeline 2.11, the sludge return pipeline 2.11 is provided with a sludge return pump 2.10 to drive sludge return, and the sequencing batch reactor is provided with a high water level 2.2 and a low water level 2.3.

[0040] The side stream return sludge fermentation system comprises a sequencing batch anaerobic fermenter 3 and a fermentation mixed liquid storage tank 4, the sequencing batch anaerobic fermenter 3 is provided with a stirrer 1.1, a side stream feeding pump 3.1, a side stream feeding pipe and a fermentation mixed liquid overflow discharge pipe 3.3, one end of the side stream feeding pump 3.1 is connected with the side stream feeding pipe 3.2, and the other end is connected to a branch line of the sludge return pipeline 2.11.

[0041] The fermentation mixed liquid storage tank 4 is provided with a fermentation mixed liquid feeding pump 4.1, and the fermentation mixed liquid feeding pump 4.1 is connected to the fermentation mixed liquid inlet pipe 1.3.

[0042] The main stream wastewater treatment system is periodically operated in a way of continuous water feeding and intermittent water discharging, the treatment period is 8-12h, four stages are arranged in each period, and the stages are an anaerobic stage 2-3h, an aerobic stage 4-6h, a sedimentation stage 1-2h and a water discharge and standing stage 1h in sequence; the hydraulic retention time (HRT) of the main stream wastewater treatment system is 15-25h; the sludge age of the system is 10-20d; and the circulating sludge flow is 50-100% of the water feeding.

[0043] The main wastewater treatment system has two working water levels: a high water level and a low water level 2.3. The low water level 2.3 is the drainage water level. During the anaerobic and aerobic stages, low-carbon source municipal wastewater is slowly added to the premixing zone 1. When the level gauge 2.1 detects the high water level 2.2, the inlet pump 1.6 is shut off to complete the water intake. During the drainage and settling stage, the drainage solenoid valve 2.5 is opened, and the supernatant from the main reaction zone 2 is discharged through the decanter 2.4. When the water level drops to the low water level 2.3, the level gauge 2.1 controls the closure of the drainage solenoid valve 2.5 to stop the drainage. The sequencing batch reactor 3 operates with intermittent sludge feeding and overflow sludge discharge. During the aerobic stage of the main wastewater treatment system, sludge is returned to the... Pipeline 2.11 diverts 3-20% (by volume) of the return liquid to the sequencing batch reactor (SBR) anaerobic digester 3. As the liquid level in the SBR 3 rises, the upper fermentation mixture is discharged via overflow and stored in the fermentation mixture storage tank 4. During the anaerobic stage of the main wastewater treatment system, the fermentation mixture feed pump 4.1 returns all the fermentation mixture to the premixing zone 1. The sludge fermentation time in the SBR 3 is 24-96 hours, the daily treatment flow rate is -1000L, the hydraulic retention time is 15 hours, the sludge retention time is 17 days, the return sludge flow rate is 100% of the influent flow rate, the side flow flow rate is 3% of the return flow rate, and the side flow sludge retention time is 1.5 days.

[0044] like Figure 2 The system effluent COD concentration was <25 mg / L, ammonia nitrogen concentration was <2 mg N / L, total phosphorus concentration was 0.6 mg P / L, total nitrogen concentration was 7.8 mg N / L, and total nitrogen removal rate was 58%; the treatment effect compared with the control group without sludge return side-flow fermentation ( Figure 4 Compared with the control group (total phosphorus concentration of 1.4 mg P / L, total nitrogen concentration of 11.4 mg N / L, and total nitrogen removal rate of 39%), the nitrogen and phosphorus removal effects were significantly enhanced. The system's residual sludge production was 58.8 g SS / d, which was significantly lower than the control group's 164.7 g SS / d, resulting in a sludge reduction of 64%.

[0045] In summary, the device method of this invention has the effect of enhancing nitrogen and phosphorus removal and sludge reduction in the treatment of urban wastewater with low carbon sources, and can achieve the national Class A standard for total nitrogen, ammonia nitrogen, total phosphorus and COD in the effluent without the need for external carbon source addition.

[0046] Example 2: Figure 1 and Figure 3As shown in the comparative example one, another embodiment of the present application is: due to the temperature fluctuation, the water temperature of urban sewage in autumn and winter decreases, and the sludge activity is low, which is not conducive to the removal of nitrogen and phosphorus in sewage and sludge fermentation. The primary effluent of a sewage treatment plant in autumn and winter (November) is taken as the processing object in the example, wherein the total nitrogen concentration is 22.6 mg N / L, the average total phosphorus concentration is 7.3 mg P / L, the average TCOD concentration is 173 mg / L, the COD / TN is 6.7, and the average water temperature is 18℃.

[0047] The applied device for fermentation-strengthened sewage denitrification and phosphorus removal and sludge reduction is as shown in Figure 1 The daily treatment flow is 1000 L, the hydraulic retention time is 18 h, the sludge retention time is 18 d, the reflux sludge flow accounts for 100% of the inflow, the side flow accounts for 10% of the reflux flow, and the side flow sludge retention time is 1.5 d.

[0048] The structure of the applied device for double-sequence batch reflux sludge side flow fermentation-strengthened sewage denitrification and phosphorus removal and sludge reduction is as shown in Figure 1 The daily treatment flow is 1000 L, the hydraulic retention time is 18 h, the sludge retention time is 18 d, the reflux sludge flow accounts for 100% of the inflow, the side flow accounts for 10% of the reflux flow, and the side flow sludge retention time is 1.5 d.

[0049] As shown in Figure 3 , the COD concentration of the system effluent is less than 25 mg / L, the ammonia nitrogen concentration is less than 2 mg N / L, the total phosphorus concentration is 0.7 mg P / L, and the total nitrogen concentration is 9.4 mg N / L; the residual sludge production of the system is 94.4 g SS / d, which is significantly lower than 164.7 g SS / d of the control group, and the sludge reduction is 42%.

[0050] In summary, the device of the present application has remarkable sludge reduction effect in the treatment of medium and low temperature urban sewage with few carbon sources, and can realize that the total nitrogen, ammonia nitrogen and COD indexes of the effluent meet the national first-level A standard without adding external carbon source, the total nitrogen concentration is less than 10 mg N / L, and the total phosphorus concentration is less than 1 mg P / L.

[0051] Example three: as Figures 5 to 9As shown, the stirrer 1.1 comprises a motor, a connecting shaft 5 and a fixed shaft 6, the motor is arranged outside the sequencing batch reactor for driving the connecting shaft 5 to rotate, the bottom end of the connecting shaft 5 is provided with an opening, the fixed shaft 6 is arranged in the connecting shaft 5, a plurality of paddles 7 are arranged on the fixed shaft 6, and a hydraulic rod 8 is fixedly connected between the top end of the fixed shaft 6 and the inner wall of the connecting shaft 5; When the mud water in the premixing zone 1 and the main reaction zone 2 is mixed, the connecting shaft 5 can be driven to rotate by the motor, at this time the connecting shaft 5 drives the fixed shaft 6 to rotate, so that the paddle 7 mixes the mud water, and the hydraulic rod 8 can be used to control the fixed shaft 6 to move up and down during the mixing process, so that the position of the paddle 7 is changed, and the paddle 7 can more efficiently mix the mud water.

[0052] The outer side wall of the fixed shaft 6 is fixedly connected with a connecting ring 9, a plurality of rectangular grooves 11 are formed in the outer side wall of the connecting ring 9, a circular shaft 12 is fixedly connected to the inner wall of the rectangular groove 11, the inner wall of the circular shaft 12 is a hollow structure, and a rotating shaft 13 is rotatably connected to the inner wall of the circular shaft 12, the side of the rotating shaft 13 away from the fixed shaft 6 is fixedly connected with the paddle 7, and a rotating assembly for driving the rotating shaft 13 to rotate is arranged on the connecting ring 9; When the mud water is stirred and mixed, the rotating shaft 13 can be driven to rotate by the rotating assembly, at this time the paddle 7 also rotates, so that the flow field changes continuously and different areas are washed, thereby effectively eliminating the dead zone caused by the fixed flow field, and more thorough and uniform mixing is achieved.

[0053] The rotating assembly comprises a first connecting plate 14 fixedly connected to the side wall of the rotating shaft 13, the outer side wall of the first connecting plate 14 is sealingly and rotatably connected to the inner wall of the circular shaft 12, the inner wall of the circular shaft 12 is fixedly connected with a second connecting plate 16, the side of the second connecting plate 16 close to the first connecting plate 14 is sealingly and rotatably connected to the outer side wall of the rotating shaft 13, the interiors of the connecting ring 9 and the fixed shaft 6 are hollow structures, the outer side wall of the fixed shaft 6 is sealingly and slidingly connected to the inner wall of the connecting shaft 5, the top surface of the connecting shaft 5 is provided with an air inlet hole 22, the inner side wall of the connecting ring 9 is provided with a through hole 20 in communication with the interior of the connecting shaft 5, the side of the circular shaft 12 away from the paddle 7 is provided with a connecting hole 10 in communication with the interior of the connecting ring 9, the outer side wall of the circular shaft 12 is provided with an air outlet hole 21, the outer side wall of the rotating shaft 13 is sealingly and rotatably connected to the circular shaft 12, and the circular shaft 12 is provided with a torsional spring (not shown in the figure) for driving the rotating shaft 13 to reset;

[0054] The fixed shaft 6 in the application moves upward under the drive of the hydraulic rod 8, and the gas enters the fixed shaft 6 from the air inlet hole 22 in the connecting shaft 5. At this time, the gas passes through the through hole 20, the inside of the connecting ring 9 and the air inlet hole 22, and finally enters the circular shaft 12. At this time, the gas pushes the first connecting plate 14, so that the first connecting plate 14 drives the rotating shaft 13 to rotate, thereby making the paddle 7 rotate. When the fixed shaft 6 moves downward, the gas will not push the first connecting plate 14. At this time, the torsional spring drives the rotating shaft 13 to reset, so that the paddle 7 can rotate.

[0055] The inner wall of the connecting ring 9 is fixedly connected with a group of fixed blocks corresponding to the rotating shaft 13. The fixed blocks are in a hollow structure. A magnetic rod 19 is slidably connected to one side of the fixed block close to the rotating shaft 13. A pair of limiting rods are fixedly connected to one side of the magnetic rod 19 close to the rotating shaft 13. A group of annularly distributed clamping grooves 15 are formed in one side of the rotating shaft 13 close to the fixed block. A spring is fixedly connected between one end of the magnetic rod 19 away from the limiting rod and the inner wall of the fixed block. The inner wall of the fixed block is fixedly connected with an electromagnet 18 repelling the magnetic rod 19. In the application, when the sludge concentration is detected to be increased, the fixed shaft 6 can be moved upward, so that the gas enters the circular shaft 12 to drive the rotating shaft 13 to rotate by ninety degrees. Then the electromagnet 18 is started to push the magnetic rod 19, so that the clamping rod is clamped with the clamping groove 15. At this time, the rotating shaft 13 is fixed, so that the angle of the paddle 7 is adjusted by ninety degrees and is fixed. The stirring intensity of the paddle 7 is increased, so as to prevent the "separation of mud and water" or "hollow phenomenon" in the high-viscosity fluid.

[0056] As shown in the drawings, Figure 10 A method for fermenting and strengthening sewage denitrification and phosphorus removal and sludge reduction, the method uses the device for fermenting and strengthening sewage denitrification and phosphorus removal and sludge reduction, and the method comprises the following steps:

[0057] S1: Two working water levels are arranged in the main sewage treatment system, which are high water level 2.2 and low water level 2.3, and the low water level 2.3 is the drainage water level. In the anaerobic and aerobic stages, the oligocarbon source (COD / TN=5-8) municipal sewage is slowly filled into the premixing area 1. When the liquid level meter 2.1 detects the high water level 2.2, the water inlet pump 1.6 is closed to complete the water inlet, and the stirrer 1.1 is used to mix the mud and water in the premixing area 1 and the main reaction area 2.

[0058] S2: In the drainage standing stage, the drainage electromagnetic valve 2.5 is opened, and the supernatant in the main reaction area 2 is discharged through the water decanter 2.4. When the liquid level is lowered to the low water level 2.3, the liquid level meter 2.1 controls the drainage electromagnetic valve 2.5 to be closed, and the drainage is stopped.

[0059] S3: The sequencing anaerobic fermenter 3 is operated in a way of intermittent sludge feeding and overflow sludge discharging, and 3-20% (volume ratio) of the reflux liquid from the sludge reflux pipeline 2.11 is branched to the sequencing anaerobic fermenter 3 in the aerobic stage of the main stream sewage treatment system;

[0060] S4: With the liquid level rising of the sequencing anaerobic fermenter 3, the upper fermentation mixed liquid is discharged by overflow and stored in the fermentation mixed liquid storage tank 4, and the fermentation mixed liquid feeding pump 4.1 returns all the fermentation mixed liquid to the premixing area 1 in the anaerobic stage of the main stream sewage treatment system, and the sludge fermentation time of the sequencing anaerobic fermenter 3 is 24-96h.

[0061] Working principle: The oligocarbon source municipal sewage is slowly filled into the premixing area 1, and the water feeding pump 1.6 is closed to complete water feeding when the high water level 2.2 is detected by the liquid level meter 2.1; in the water discharging and standing stage, the water discharging electromagnetic valve 2.5 is opened, the supernatant in the main reaction area 2 is discharged through the water decanter 2.4, and the liquid level is lowered to the low water level 2.3, the water discharging electromagnetic valve 2.5 is controlled to be closed by the liquid level meter 2.1, and the water discharging is stopped; the sequencing anaerobic fermenter 3 is operated in a way of intermittent sludge feeding and overflow sludge discharging, and 3-20% (volume ratio) of the reflux liquid from the sludge reflux pipeline 2.11 is branched to the sequencing anaerobic fermenter 3 in the aerobic stage of the main stream sewage treatment system; with the liquid level rising of the sequencing anaerobic fermenter 3, the upper fermentation mixed liquid is discharged by overflow and stored in the fermentation mixed liquid storage tank 4, and the fermentation mixed liquid feeding pump 4.1 returns all the fermentation mixed liquid to the premixing area 1 in the anaerobic stage of the main stream sewage treatment system, and the sludge fermentation time of the sequencing anaerobic fermenter 3 is 24-96h, the daily treatment flow is-1000L, the hydraulic retention time is 15h, the sludge retention time is 17d, the reflux sludge flow accounts for 100% of the water inflow, the side flow accounts for 3% of the reflux flow, and the side sludge retention time is 1.5d.

[0062] The above, front, left, right, up and down are based on the figures in the description Figure 1 As the standard, the side of the device facing the observer is defined as the front, the left side of the observer is defined as the left, and so on.

[0063] In the description of the present application, it should be understood that the orientations or positional relationships indicated by the terms "center", "longitudinal", "transverse", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as limiting the scope of protection of the present application.

[0064] The above shows and describes the basic principles, main features and advantages of the present application. Those skilled in the art should understand that the present application is not limited to the above-mentioned embodiments, and the above-mentioned embodiments and descriptions in the specification are only to illustrate the principles of the present application. Without departing from the spirit and scope of the present application, various changes and improvements can be made to the present application, and these changes and improvements all fall within the scope of the claimed present application. The scope of protection of the present application is defined by the appended claims and their equivalents.

Claims

1. A device for enhancing wastewater denitrification and phosphorus removal and sludge reduction by fermentation, comprising a main stream wastewater treatment system and a side stream sludge fermentation system, wherein the main stream wastewater treatment system comprises a sequencing batch reactor of cyclic activated sludge method; a partition plate (1.5) with water holes is arranged in the sequencing batch reactor, and the sequencing batch reactor is divided into a pre-mixing zone (1) and a main reaction zone (2) by the partition plate (1.5); a stirrer (1.1) is arranged in the pre-mixing zone (1) and the main reaction zone (2), the pre-mixing zone (1) is provided with a wastewater inlet pipe (1.2), a fermentation mixed liquor inlet pipe (1.3) and a return sludge inlet pipe (1.4), and the wastewater inlet pipe (1.2) is connected with a water inlet pump (1.6). characterized in that A liquid level meter (2.1), a decanter (2.4), a drain electromagnetic valve (2.5), a water outlet pipe (2.6), an aerator (2.7), an aeration disc (2.8), a residual sludge discharge pipe (2.9), a sludge return pipeline (2.11) and a sludge return pump (2.10) are arranged in the main reaction zone (2), the sludge return pump (2.10) is arranged on the sludge return pipeline (2.11) to drive sludge return, and a high water level (2.2) and a low water level (2.3) are arranged in the sequencing batch reactor. The side stream sludge fermentation system comprises a sequencing batch anaerobic fermenter (3) and a fermentation mixed liquor storage tank (4), wherein the sequencing batch anaerobic fermenter (3) is provided with a stirrer (1.1), a side stream feeding pump (3.1), a side stream feeding pipe (3.2) and a fermentation mixed liquor overflow discharge pipe (3.3), one end of the side stream feeding pump (3.1) is connected with the side stream feeding pipe (3.2), and the other end is connected with a branch line of the sludge return pipeline (2.11).

2. The device for enhancing denitrification and dephosphorization of wastewater and sludge reduction by fermentation according to claim 1, characterized in that: The fermentation mixed liquor storage tank (4) is provided with a fermentation mixed liquor feeding pump (4.1) connected with the fermentation mixed liquor inlet pipe (1.3).

3. The device for enhancing denitrification and dephosphorization of wastewater and sludge reduction by fermentation according to claim 2, characterized in that: The stirrer (1.1) comprises a motor, a connecting shaft (5) and a fixed shaft (6), the motor is arranged outside the CASS reactor and used to drive the connecting shaft (5) to rotate, the bottom end of the connecting shaft (5) is open, the fixed shaft (6) is arranged in the connecting shaft (5), a plurality of paddle blades (7) are arranged on the fixed shaft (6), and a hydraulic rod (8) is fixedly connected between the top end of the fixed shaft (6) and the inner wall of the connecting shaft (5).

4. The device for enhancing wastewater denitrification and dephosphorization and sludge reduction by fermentation according to claim 3, characterized in that: A group of connecting rings (9) are fixedly connected to the outer side wall of the fixed shaft (6), a group of rectangular grooves (11) are arranged on the outer side wall of the connecting ring (9), a circular shaft (12) is fixedly connected to the inner wall of the rectangular groove (11), the inner wall of the circular shaft (12) is a hollow structure, a rotating shaft (13) is rotatably connected to the circular shaft (12), the rotating shaft (13) is fixedly connected with the paddle blade (7) away from the fixed shaft (6), and a rotating assembly for driving the rotating shaft (13) to rotate is arranged on the connecting ring (9).

5. The device for enhancing wastewater denitrification and dephosphorization and sludge reduction by fermentation according to claim 4, characterized in that: ​ 6. The device for enhancing wastewater denitrification and dephosphorization and sludge reduction by fermentation according to claim 5, characterized in that: ​ 7. The device for enhancing wastewater denitrification and dephosphorization and sludge reduction by fermentation according to claim 6, characterized in that: The rotating assembly includes a first connecting plate (14) fixedly connected with the side wall of the rotating shaft (13), the outer side wall of the first connecting plate (14) is sealingly and rotatably connected with the inner wall of the circular shaft (12), the inner wall of the circular shaft (12) is fixedly connected with a second connecting plate (16), the side of the second connecting plate (16) close to the first connecting plate (14) is sealingly and rotatably connected with the outer side wall of the rotating shaft (13), the connecting ring (9) and the fixed shaft (6) are both hollow structures, the outer side wall of the fixed shaft (6) is sealingly and slidingly connected with the inner wall of the connecting shaft (5), the top surface of the connecting shaft (5) is provided with an air inlet hole (22), the inner side wall of the connecting ring (9) is provided with a through hole (20) in communication with the inside of the connecting shaft (5), the side of the circular shaft (12) away from the paddle (7) is provided with a connecting hole (10) in communication with the inside of the connecting ring (9), the outer side wall of the circular shaft (12) is provided with an air outlet hole (21), the outer side wall of the rotating shaft (13) is sealingly and rotatably connected with the circular shaft (12), and the circular shaft (12) is provided with a torsional spring for driving the rotating shaft (13) to reset.

8. The device for enhancing wastewater denitrification and dephosphorization and sludge reduction by fermentation according to claim 7, characterized in that: The inner wall of the connecting ring (9) is fixedly connected with a group of fixed blocks (17) corresponding to the rotating shaft (13), the inside of the fixed block (17) is a hollow structure, the side of the fixed block (17) close to the rotating shaft (13) is slidingly connected with a magnetic rod (19), the side of the magnetic rod (19) close to the rotating shaft (13) is fixedly connected with a pair of limiting rods, the side of the rotating shaft (13) close to the fixed block (17) is provided with a group of annularly and uniformly distributed clamping grooves (15), the end of the magnetic rod (19) away from the limiting rod is fixedly connected with a spring between the inner wall of the fixed block (17), and the inner wall of the fixed block (17) is fixedly connected with an electromagnet (18) repelling the magnetic rod (19).

9. A method for denitrification and dephosphorization of sewage and sludge reduction by fermentation intensification, characterized in that the method uses the device for denitrification and dephosphorization of sewage and sludge reduction by fermentation intensification according to claim 8. The method comprises the following steps: S1: two working water levels are arranged in the main stream sewage treatment system, which are high water level and low water level (2.3), the low water level (2.3) is the drainage water level, during the anaerobic and aerobic stages, the oligocarbon source municipal sewage is slowly added to the premixing area (1), when the high water level (2.2) is detected by the liquid level meter (2.1), the water inlet pump (1.6) is closed to complete water inlet, and the stirrer (1.1) is used to mix the mud and water in the premixing area (1) and the main reaction area (2); S2: during the drainage standing stage, the drainage electromagnetic valve (2.5) is opened, the supernatant in the main reaction area (2) is discharged through the water decanter (2.4), when the liquid level is lowered to the low water level (2.3), the liquid level meter (2.1) controls the drainage electromagnetic valve (2.5) to be closed to stop drainage; S3: the sequencing batch anaerobic fermenter (3) is operated in the intermittent sludge inlet and overflow sludge discharge mode, during the aerobic stage of the main stream sewage treatment system, 3-20% (volume ratio) of the backflow liquid is diverted from the sludge backflow pipeline (2.11) to the sequencing batch anaerobic fermenter (3). S4: With the liquid level of the sequencing anaerobic fermentor (3) rising, the upper fermentation mixed liquor is discharged by overflow and stored in the fermentation mixed liquor storage tank (4). In the anaerobic stage of the main stream sewage treatment system, the fermentation mixed liquor feed pump (4.1) returns all the fermentation mixed liquor to the premixing zone (1). The sludge fermentation time of the sequencing anaerobic fermentor (3) is 24-96h.

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