A device and method for achieving sludge reduction by using weak electrical stimulation anaerobic side stream reactor

Abstract

The invention relates to the technical field of sewage treatment, and specifically discloses a device and method for realizing sludge reduction by a weak electric stimulation anaerobic side stream reactor, comprising: an anoxic tank, an aerobic tank, a secondary sedimentation tank and a weak electric stimulation side stream anaerobic reactor; the anoxic tank, the aerobic tank and the secondary sedimentation tank are connected in sequence along the sewage flow direction; the weak electric stimulation anaerobic side stream reactor has a mud inlet, a first mud outlet and a second mud outlet, the mud inlet is connected to the secondary sedimentation tank, the first mud outlet is connected to the anoxic tank, the second mud outlet is connected to the aerobic tank, and the first mud outlet is located above the second mud outlet; an internal reflux pipeline is arranged between the anoxic tank and the aerobic tank; the device for realizing sludge reduction by the weak electric stimulation anaerobic side stream reactor solves the problems of low reduction efficiency, poor process stability and large floor space in the existing ASSR process through weak electric stimulation technology, combined with optimized reactor structure design and operation mode.

Description

Technical Field

[0001] The invention relates to the technical field of sewage treatment, and in particular to a device and method for realizing sludge reduction in a weak electrical stimulation anaerobic side stream reactor. Background Art

[0002] In recent years, the anaerobic side-stream reactor (ASSR) has attracted widespread attention due to its simple construction, significant reduction effect and low operating cost. ASSR achieves sludge lysis, latent growth and functional bacterial enrichment by constructing an aerobic / anaerobic environment alternately, thereby achieving the purpose of sludge reduction and stable operation of the system. However, the traditional ASSR process still faces the following main problems:

[0003] 1. Difficulty in improving reduction efficiency: The sludge reduction of the ASSR process mainly relies on the natural metabolic process and endogenous consumption of microorganisms, but the sludge lysis rate is low, which makes it difficult to meet the needs of efficient reduction. In order to improve the reduction efficiency, existing studies have attempted to combine physical and chemical technologies with the ASSR process. For example, physical methods such as ultrasound and heat treatment significantly improve the reduction effect by enhancing sludge lysis, but their equipment is complex, the operating cost is high, and the energy consumption is large, which limits their wide application; although chemical technologies such as ozone and ferrate oxidation can improve the lysis efficiency, they are easy to inhibit the microbial community in the reactor, destroy the ecological balance, and even cause secondary pollution. The above problems significantly restrict the efficiency improvement and environmental friendliness of the ASSR process.

[0004] 2. Poor process stability: The reduction effect of the ASSR process is highly dependent on the metabolic activity of microorganisms and the enrichment of functional bacterial communities, but the microbial community structure is easily affected by environmental conditions (such as temperature, pH, redox potential, etc.) and fluctuations in influent water quality, resulting in large fluctuations in sludge reduction efficiency. Existing technologies have limited research on microbial regulation, and lack targeted methods to regulate the metabolic activity of functional bacterial communities and the stability of community structure.

[0005] 3. Large floor space: Due to the slow reaction rate of microorganisms, a long sludge retention time is required to ensure sufficient lysis and reduction of sludge. This long retention time directly leads to a significant increase in the demand for reactor volume in the ASSR system, and the large floor space has become an important limiting factor in the engineering application of sewage treatment plants with large sludge treatment requirements. In addition, the large floor space not only increases the construction cost of the system, but also increases the economic burden of operation and maintenance, which further restricts the large-scale promotion and application potential of the ASSR process. Summary of the invention

[0006] In order to solve the above-mentioned technical problems, the present invention provides a device for achieving sludge reduction by using a weak electric stimulation anaerobic side stream reactor. Through weak electric stimulation technology, combined with optimized reactor structure and operation mode, the problems of low reduction efficiency, poor process stability and large footprint in the existing ASSR process are solved.

[0007] To solve the above problems, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides a device for achieving sludge reduction by using a weak electrical stimulation anaerobic side stream reactor, comprising: an anoxic tank, an aerobic tank, a secondary sedimentation tank and a weak electrical stimulation side stream anaerobic reactor.

[0009] The anoxic tank, the aerobic tank and the secondary sedimentation tank are connected in sequence along the flow direction of the sewage.

[0010] The weak electrical stimulation anaerobic side stream reactor has a mud inlet, a first mud outlet and a second mud outlet. The mud inlet is connected to the secondary sedimentation tank, the first mud outlet is connected to the anoxic tank, the second mud outlet is connected to the aerobic tank, and the first mud outlet is located above the second mud outlet.

[0011] An internal reflux pipeline is arranged between the anoxic pool and the aerobic pool.

[0012] In the device for achieving sludge reduction by using a weakly electrically stimulated anaerobic side stream reactor provided in at least one embodiment of the present disclosure, the weakly electrically stimulated anaerobic side stream reactor comprises a side stream reaction tank, a DC power supply, an agitator, an anode electrode, a cathode electrode and a telescopic electrode holder.

[0013] The mud inlet, the first mud outlet and the second mud outlet are all located on the side of the side stream reaction tank.

[0014] The DC power supply is located outside the lateral flow reaction tank, and a sampling pipeline is arranged on the lateral flow reaction tank.

[0015] A stirring paddle is arranged below the stirrer, and the stirring paddle is located in the side stream reaction tank. The stirrer is fixedly arranged at the middle of the outer top surface of the side stream reaction tank.

[0016] The anode electrode is connected to the bottom of the telescopic electrode holder, the cathode electrode is fixedly arranged in the lateral flow reaction tank, and the telescopic electrode holder is connected to the middle part of the inner top surface of the lateral flow reaction tank.

[0017] In the device for achieving sludge reduction by using a weakly electrically stimulated anaerobic side stream reactor provided in at least one embodiment of the present disclosure, the anode electrode has a shape of sheet, mesh, velvet, columnar or spherical.

[0018] In the device for achieving sludge reduction by using a weakly electrically stimulated anaerobic side stream reactor provided in at least one embodiment of the present disclosure, the cathode electrode may be in the shape of a sheet, a mesh, a velvet, a column or a sphere.

[0019] In the device for achieving sludge reduction by using a weakly electrically stimulated anaerobic side stream reactor provided in at least one embodiment of the present disclosure, the anode electrode is a high-purity graphite electrode.

[0020] In the device for achieving sludge reduction by using a weakly electrically stimulated anaerobic side stream reactor provided in at least one embodiment of the present disclosure, the cathode electrode is a high-purity PAN-based graphite soft felt.

[0021] In the device for achieving sludge reduction by using a weakly electrically stimulated anaerobic side stream reactor provided by at least one embodiment of the present disclosure, the cathode electrode is in a sheet shape and surrounds and is fixed on the inner wall of the side stream reaction tank.

[0022] In the device for achieving sludge reduction by using a weakly electrically stimulated anaerobic side stream reactor provided by at least one embodiment of the present disclosure, the anode electrode is tubular, and the anode electrode is also configured to allow the agitator to pass through.

[0023] In a second aspect, the present invention also provides a working method of a device for achieving sludge reduction by using a weak electrical stimulation anaerobic side stream reactor, comprising the following steps:

[0024] 1) The sewage is sequentially passed through an anoxic tank and an aerobic tank for anoxic treatment and aerobic treatment respectively, and the mixed liquid in the aerobic tank is passed through a secondary sedimentation tank for solid-liquid separation.

[0025] 2) Part of the residual sludge in the secondary sedimentation tank is introduced into the weak electric stimulation anaerobic side stream reactor at a first preset exchange frequency for weak electric stimulation anaerobic treatment, and the treatment time is set; the supernatant and the lower layer of mud and water mixture produced after the treatment in the weak electric stimulation anaerobic side stream reactor are discharged to the anoxic tank and the aerobic tank respectively at a second preset exchange frequency, wherein each discharge is carried out alternately, the supernatant is discharged once and the lower layer of mud and water mixture is discharged next time; the residual sludge in the secondary sedimentation tank enters the side stream reactor at a preset sludge return ratio, and the residual sludge in the secondary sedimentation tank enters the weak electric stimulation anaerobic side stream reactor at a certain sludge exchange law.

[0026] The voltage of the weak electrical stimulation anaerobic treatment is 0.1-0.9V, and the time of the weak electrical stimulation anaerobic treatment is 3-15 days.

[0027] Among them, after the weak electrical stimulation anaerobic treatment has been running stably for 0-3 months, the weak electrical stimulation anaerobic treatment adopts an intermittent operation mode, and the intermittent operation mode includes but is not limited to the following forms: operation in days, operation in hours or other periodic intermittent operation modes.

[0028] The beneficial effects of the present invention are as follows: compared with the prior art, the present invention shows obvious advantages in key aspects such as sludge reduction efficiency, process stability and floor space by introducing weak electrical stimulation technology and optimized device design. At the same time, the present invention combines intermittent operation mode and reasonable electrode layout to further enhance the adaptability of the system and the long-term reliability of operation.

[0029] The present invention uses weak electrical stimulation technology to build a stable reducing environment, which enhances the cleavage rate of organic matter in sludge and the metabolic efficiency of microorganisms. The electron transfer channel provided by weak electrical stimulation effectively optimizes the electron transport chain of microorganisms, while accelerating the decomposition of extracellular polymers (EPS), releasing more soluble organic matter, and further promoting sludge cleavage. Compared with the traditional ASSR process, the sludge reduction efficiency of the present invention under the same conditions can be increased by more than 30%.

[0030] The present invention uses weak electrical stimulation technology to promote the enrichment of functional microorganisms such as denitrifying bacteria and denitrifying polyphosphate bacteria, optimize the microbial community structure, and thus enhance the system's adaptability to nitrogen and phosphorus removal. In addition, weak electrical stimulation forms a stable potential gradient on the surface of microbial cell membranes, activates key enzyme activities, improves microorganisms' tolerance to water quality fluctuations, temperature and pH changes, and ensures long-term stable operation of the process. Compared with traditional technologies, the present invention significantly reduces the risk of operational instability.

[0031] The anode electrode of the present invention adopts a hollow porous cylindrical structure, which not only improves the uniformity of the electric field distribution, but also optimizes the mass transfer conditions in combination with the stirring paddle; the cathode graphite felt electrode surrounds the inner wall of the side flow reactor to maximize the coverage of the electrochemical active area. This optimized design improves the overall processing efficiency of the reactor and extends the service life of the equipment. In addition, the electrode material uses high-purity graphite and surface functional group-modified graphite felt, which has excellent conductivity, corrosion resistance and chemical stability, ensuring the reliability of long-term operation.

[0032] The present invention strengthens the performance of the sewage treatment system by constructing an internal circulation path for the supernatant and the sludge mixture. The high-efficiency carbon source is returned to the anoxic tank to enhance denitrification and phosphorus release by polyphosphate bacteria, reducing the demand for external carbon sources; the sludge mixture is returned to the aerobic tank to introduce functional microorganisms (such as denitrifying polyphosphate bacteria, electrogenic bacteria, etc.) enriched by weak electrical stimulation, optimize the microbial community structure, improve the organic matter degradation efficiency and sludge reduction effect, and construct a green, low-carbon, efficient and economical sewage treatment system.

[0033] The present invention adopts an intermittent weak-current operation mode, which significantly reduces overall energy consumption and avoids problems of electrode passivation and equipment aging caused by long-term continuous operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0035] Figure 1 This is a schematic diagram of a device for achieving sludge reduction by using a weakly electrically stimulated anaerobic side stream reactor according to the present invention.

[0036] Figure 2 This is a schematic diagram of the structure of the weakly electrically stimulated side-flow anaerobic reactor.

[0037] Figure 3 This is a comparison chart of the inlet and outlet COD of the four systems in the experimental example.

[0038] Figure 4 This is a comparison chart of the inlet and outlet water TN of the four systems in the experimental example.

[0039] Figure 5 This is a comparison chart of the inlet and outlet water TP of the four systems in the experimental example.

[0040] Figure 6 This is a comparison chart of ammonia nitrogen in the inlet and outlet water of the four systems in the experimental example.

[0041] Figure 7 This is a comparison chart of the total sludge discharge of the four systems in the experimental example.

[0042] In the figure:

[0043] 10. Weak electric stimulation side stream anaerobic reactor; 1. Side stream reaction tank; 2. DC power supply; 3. Agitator; 4. Anode electrode; 5. Cathode electrode; 6. Telescopic electrode holder; 7. Mud inlet; 8. First mud outlet; 9. Sampling pipeline; 11. Agitator paddle;

[0044] 20. Anoxic pool;

[0045] 30. Aerobic pool;

[0046] 40. Secondary sedimentation tank;

[0047] 50. Internal reflux pipeline;

[0048] 60. External return pipeline. DETAILED DESCRIPTION

[0049] The technical solutions in the embodiments will be described clearly and completely below in conjunction with the drawings in the embodiments. Obviously, the described embodiments are only a part of the embodiments, rather than all the embodiments.

[0050] Example:

[0051] like Figure 1 and 2 As shown, an embodiment of the present invention provides a sludge reduction device for a weak electric stimulation anaerobic side stream reactor. It includes a weak electric stimulation side stream anaerobic reactor 10, an anoxic tank 20, an aerobic tank 30 and a secondary sedimentation tank 40; the anoxic tank, the aerobic tank and the secondary sedimentation tank are connected in sequence along the sewage flow direction. An internal return pipeline 50 is provided between the anoxic tank and the aerobic tank. The secondary sedimentation tank 40 is connected to an external return pipeline 60, and the external return pipeline 60 is connected to the water inlet end of the anoxic tank 20.

[0052] In this embodiment, the structure of the weak electrical stimulation anaerobic side stream reactor is as follows: Figure 2 As shown, the weak electrical stimulation anaerobic side stream reactor includes a side stream reaction tank 1, a DC power supply 2, a stirrer 3, an anode electrode 4, a cathode electrode 5 and a telescopic electrode holder 6.

[0053] Specifically, a mud inlet 7, a first mud outlet 8 and a second mud outlet are provided on the side of the side stream reaction tank 1. A DC power supply 2 is provided outside the side stream reaction tank 1, and a sampling pipeline 9 is provided on the side stream reaction tank 1.

[0054] Specifically, the first mud outlet 8 is connected to the anoxic pool 20 through a pipeline system; the second mud outlet is connected to the aerobic pool 30 through a pipeline system, and the first mud outlet 8 is located above the second mud outlet.

[0055] Specifically, the stirrer 3 is fixed at the middle of the outer top surface of the side stream reaction tank 1, the end of the stirrer 3 is located in the side stream reaction tank 1, and a stirring paddle 11 is provided at the end of the stirrer 3.

[0056] Specifically, the anode electrode 4 is connected below the telescopic electrode holder 6 , the cathode electrode 5 is fixed in the lateral flow reaction tank 1 , and the telescopic electrode holder 6 is connected to the middle of the inner top surface of the lateral flow reaction tank 1 .

[0057] Specifically, the anode electrode 4 is made of a metal material, a carbon material, an oxide material, a composite material or a modified form of the above materials as a substrate, and preferably a high-purity graphite electrode is used.

[0058] The anode electrode 4 can be in the shape of a sheet, a mesh, a velvet, a column or a sphere, and preferably adopts a hollow cylindrical design, which is tubular as a whole, wherein the hollow portion is used to accommodate a stirring paddle to pass through so as not to affect the normal operation of the stirrer.

[0059] Specifically, the cathode electrode 5 is made of a metal material, a carbon material, an oxide material, a composite material or the above materials as a modified substrate; preferably, high-purity PAN-based graphite soft felt is used, preferably a porous structure modified with surface functional groups, and the thickness is 2-15 mm.

[0060] The cathode electrode 5 can be in the shape of a sheet, a mesh, a velvet, a column or a sphere, and the cathode electrode 5 is fixed inside the side flow reaction tank; preferably, a sheet is used to surround and fix it on the inner wall of the side flow reaction tank, surrounding it 1-5 times, and the cathode electrode 5 has corresponding openings reserved at the mud inlet and mud outlet positions; the telescopic electrode holder 6 is a mechanical structure with adjustable height, and the telescopic electrode holder 6 is an electric slide or a manual slide, etc., which can realize the precise lifting and lowering of the anode electrode through manual or automatic control.

[0061] The working method of the sludge reduction device of the weak electrical stimulation anaerobic side stream reactor comprises the following steps:

[0062] 1) The sewage is passed through an anoxic tank and an aerobic tank for anoxic treatment and aerobic treatment respectively, and the mixed liquid in the aerobic tank is passed through a secondary sedimentation tank for solid-liquid separation.

[0063] 2) Part of the residual sludge in the secondary sedimentation tank enters the weak electric stimulation anaerobic side stream reactor at the first preset exchange frequency for weak electric stimulation anaerobic treatment, and the treatment time is set. The supernatant and the lower mud-water mixture produced after the treatment in the weak electric stimulation anaerobic side stream reactor are discharged to the anoxic tank and the aerobic tank respectively at the second preset exchange frequency, wherein each discharge is carried out alternately, the supernatant is discharged once, and the lower mud-water mixture is discharged next time; the residual sludge in the secondary sedimentation tank enters the side stream reactor at a preset sludge return ratio. The residual sludge in the secondary sedimentation tank enters the weak electric stimulation anaerobic side stream reactor at a certain sludge exchange law.

[0064] The first preset exchange frequency is equal to the second preset exchange frequency, which is 1-30 times / day, and the volume of sludge in the secondary sedimentation tank entering the weak electric stimulation anaerobic side stream reactor is equal to the total volume of the supernatant discharged from the weak electric stimulation anaerobic side stream reactor into the anoxic tank and the mud-water mixture discharged into the aerobic tank. The sludge exchange rate entering the weak electric stimulation anaerobic side stream reactor is 5-20%.

[0065] The voltage of weak electric stimulation anaerobic treatment is 0.1-0.9V, and the time of weak electric stimulation anaerobic treatment is 3-15 days. After the weak electric stimulation anaerobic treatment has been running stably for 0-3 months, the weak electric stimulation can adopt an intermittent operation mode.

[0066] The intermittent operation mode includes but is not limited to the following forms: operation in days, operation in hours or other periodic intermittent operation modes.

[0067] Experimental example:

[0068] The sludge reduction effect of the weak electrical stimulation anaerobic side stream reactor will be studied below to further illustrate the beneficial effects of the present invention.

[0069] Four systems were selected for comparison, namely: A / O (control group), A / O-ASSR (traditional anaerobic side stream reactor), A / O-EASSR0.2 (weak electrical stimulation voltage 0.2V), A / O-EASSR0.4 (weak electrical stimulation voltage 0.4V). The sludge concentration in the aerobic pool was controlled at 3500mg / L. If it exceeded, the sludge was discharged and the amount of sludge discharged was recorded as a comparison of the sludge reduction effect. The sludge return ratio was 10%, the exchange frequency was 4 times / day, and the mode of once entering the supernatant and once entering the sludge-water mixture was adopted. The influent COD was 400-500mg / L; TN was 60-70mg / L; TP was 2-3mg / L.

[0070] The experimental results are as follows Figure 3 As shown in the figure, the EASSR system is superior to the A / O system and the traditional A / O-ASSR system in terms of COD removal efficiency. The effluent COD of the A / O system is 49.11 mg / L, while that of the A / O-ASSR is 53.86 mg / L. The A / O-EASSR0.2 and A / O-EASSR0.4 are reduced to 46.84 mg / L and 44.48 mg / L, respectively. Compared with the traditional anaerobic side stream reactor (A / O-ASSR), the EASSR system has a higher COD removal rate, especially under the condition of 0.4V voltage. The reason is that weak electrical stimulation significantly enhances the degradation ability of microorganisms to complex organic matter by providing additional electron donors and optimizing the electron transport chain, further strengthening sludge lysis and organic matter decomposition.

[0071] In terms of TN removal, the EASSR system showed higher removal efficiency. Figure 4 As shown in the figure, the effluent TN concentration of the A / O system is 14.71 mg / L, while that of the traditional A / O-ASSR system is reduced to 12.63 mg / L, and that of A / O-EASSR0.2 and A / O-EASSR0.4 is further reduced to 12.59 mg / L and 12.51 mg / L. Compared with the traditional ASSR, the EASSR system enhances the activity of denitrifying bacteria through weak electrical stimulation and significantly optimizes the denitrification process. At the same time, the presence of the electric field promotes the release and recycling of carbon sources in the side-stream anaerobic reactor, providing sufficient carbon sources for denitrification, thereby improving the nitrogen removal capacity.

[0072] In the experiment, the removal effects of the four systems on TP were slightly different, but the EASSR system was slightly better. Figure 5 As shown in the figure, the effluent TP concentration of the A / O system is 0.15 mg / L, the traditional A / O-ASSR system further reduces it to 0.10 mg / L, and the A / O-EASSR0.2 and A / O-EASSR0.4 both drop to 0.08 mg / L. Compared with the traditional ASSR, the EASSR system promotes the enrichment of polyphosphate bacteria through weak electrical stimulation.

[0073] In terms of ammonia nitrogen removal, the effluent ammonia nitrogen concentrations of the four systems were all lower than 0.53 mg / L, showing similar removal effects. Figure 6 As shown. Among them, the performance of the traditional A / O-ASSR system and the A / O-EASSR system are better than that of the A / O system, indicating that the introduction of the anaerobic side stream reactor plays a certain role in the removal of ammonia nitrogen. However, the EASSR system indirectly reduces the ammonia nitrogen burden of the mainstream system by strengthening the carbon source release and denitrification process, making the ammonia nitrogen treatment more stable. Although the traditional ASSR system performs well, the internal circulation carbon source optimization mechanism of the EASSR system further ensures the efficient removal of ammonia nitrogen.

[0074] The results of the cumulative sludge discharge are as follows: Figure 7 As shown in the figure, the EASSR system is significantly better than other systems in terms of sludge reduction effect. The A / O system has the highest cumulative sludge discharge of 17.55g, while the traditional A / O-ASSR system is reduced to 14.3g, and A / O-EASSR0.2 and A / O-EASSR0.4 are further reduced to 10.445g and 8.34g. Compared with the traditional ASSR system, the EASSR system has a greater reduction in sludge discharge. The reason for the improvement in its reduction efficiency is that weak electrical stimulation provides a stable reducing environment, promotes sludge lysis and degradation of extracellular polymers (EPS), and enhances the endogenous metabolism and alienation metabolism of microorganisms. Although the traditional ASSR also has a certain sludge lysis function, its efficiency is lower than that of the EASSR system, indicating the core role of weak electrical stimulation in sludge reduction.

[0075] Although the embodiments of the present application have been shown and described above, the scope of protection of the present invention is not limited thereto, and any changes or substitutions that are not conceivable through creative work should be included in the scope of protection of the present invention; unless explicitly stated, any elements, actions or instructions used in this document should not be interpreted as critical or necessary.

Claims

1. A device for achieving sludge reduction by using weak electrical stimulation anaerobic side stream reactor, characterized in that: include: Anoxic tanks, aerobic tanks, secondary sedimentation tanks and weakly electrically stimulated anaerobic side stream reactors; The anoxic tank, the aerobic tank and the secondary sedimentation tank are connected in sequence along the flow direction of the sewage; The weak electrical stimulation anaerobic side stream reactor comprises a side stream reaction tank, a DC power supply, an agitator, an anode electrode and a cathode electrode. The weak electrical stimulation anaerobic side stream reactor has a mud inlet, a first mud outlet and a second mud outlet. The mud inlet is connected to the secondary sedimentation tank. The first mud outlet is connected to the anoxic tank for discharging the supernatant to the anoxic tank. The second mud outlet is connected to the aerobic tank for discharging the lower mud-water mixture to the aerobic tank. The first mud outlet is located above the second mud outlet. An internal reflux pipeline is provided between the anoxic tank and the aerobic tank; The cathode electrode is in sheet shape and surrounds and is fixed on the inner wall of the side stream reaction tank; The anode electrode is tubular, and the anode electrode is also configured to allow the stirrer to pass through; The processing voltage of the weak electrical stimulation anaerobic side flow reactor is 0.1-0.9V.

2. The device for achieving sludge reduction by using a weakly electrically stimulated anaerobic side stream reactor according to claim 1, characterized in that: The weak electrical stimulation anaerobic side stream reactor also includes a telescopic electrode holder; The mud inlet, the first mud outlet and the second mud outlet are all located on the side wall of the side stream reaction tank; The DC power supply is located outside the lateral flow reaction tank, and a sampling pipeline is provided on the lateral flow reaction tank; A stirring paddle is arranged below the stirrer, the stirring paddle is located in the side stream reaction tank, and the stirrer is fixedly arranged in the middle of the outer top surface of the side stream reaction tank; The anode electrode is connected to the bottom of the telescopic electrode holder, and the telescopic electrode holder is connected to the middle of the inner top surface of the side flow reaction tank.

3. A method for operating the device for achieving sludge reduction by using a weakly electrically stimulated anaerobic side stream reactor as claimed in claim 1 or 2, characterized in that: The following steps are involved: 1) The sewage is sequentially passed through an anoxic tank and an aerobic tank for anoxic treatment and aerobic treatment respectively, and the mixed liquid in the aerobic tank is passed through a secondary sedimentation tank for solid-liquid separation; 2) Part of the residual sludge in the secondary sedimentation tank is introduced into the weak electric stimulation anaerobic side stream reactor at a first preset exchange frequency for weak electric stimulation anaerobic treatment, and the treatment time is set; the supernatant produced after the treatment in the weak electric stimulation anaerobic side stream reactor is discharged to the anoxic tank at a second preset exchange frequency; the lower layer of mud and water mixture produced after the treatment in the weak electric stimulation anaerobic side stream reactor is discharged to the aerobic tank at a second preset exchange frequency, wherein the discharge of the supernatant and the discharge of the lower layer of mud and water mixture are carried out alternately; the residual sludge in the secondary sedimentation tank enters the weak electric stimulation anaerobic side stream reactor at a preset sludge return ratio, and the residual sludge in the secondary sedimentation tank enters the weak electric stimulation anaerobic side stream reactor at a certain sludge exchange rate.

4. The working method of the device for achieving sludge reduction by using weak electrical stimulation anaerobic side stream reactor according to claim 3 is characterized in that: After the weak electrical stimulation anaerobic treatment has been running stably for 0-3 months, the weak electrical stimulation anaerobic treatment adopts an intermittent operation mode.

5. The working method of the device for achieving sludge reduction by using weak electrical stimulation anaerobic side stream reactor according to claim 3 is characterized by: The voltage of the weak electrical stimulation anaerobic treatment is 0.1-0.9V, and the time of the weak electrical stimulation anaerobic treatment is 3-15 days.

6. The working method of the device for achieving sludge reduction by using weak electrical stimulation anaerobic side stream reactor according to claim 5, characterized in that: The first preset exchange frequency is equal to the second preset exchange frequency, which is 1-30 times / day. The volume of residual sludge in the secondary sedimentation tank entering the weak electric stimulation anaerobic side stream reactor is equal to the total volume of the supernatant discharged from the weak electric stimulation anaerobic side stream reactor into the anoxic tank and the mud-water mixture discharged into the aerobic tank. The sludge exchange rate entering the weak electric stimulation anaerobic side stream reactor is 5-20%.

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