Sewage treatment system for food industry wastewater

Abstract

The utility model discloses a sewage treatment system for food industry wastewater, which comprises an anaerobic tank, a primary anoxic tank and a primary aerobic tank which are sequentially connected in series along the water inlet direction. A second-stage anoxic tank, a second-stage aerobic tank, a third-stage anoxic tank, a third-stage aerobic tank and a secondary sedimentation tank are sequentially connected in series forwards in the first-stage aerobic tank in the sewage flowing direction, and a sludge backflow pipeline is arranged at the bottom of the secondary sedimentation tank and flows back to the anaerobic tank; aeration devices are arranged at the bottoms of the first-stage anoxic tank, the first-stage aerobic tank, the second-stage aerobic tank and the third-stage aerobic tank. The nitrogen and phosphorus removal effect of the biochemical pool is effectively improved, and the device is suitable for being popularized in villages and towns with many food processing industries.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of sewage treatment, and specifically relates to a sewage treatment system for food industrial wastewater. BACKGROUND

[0002] At present, the rural revitalization of China cannot do without the development of a large number of township enterprises, and the most common in township enterprises is food processing enterprises, which deeply process rural agricultural products to improve their industrial value. However, the water consumption and wastewater volume are very large in various food processing processes, which will produce a large amount of food industrial wastewater with high nitrogen and phosphorus pollution. Compared with cities, the sewage treatment capacity of rural areas is relatively weak, the drainage system construction is not perfect, and the combined drainage of rainwater and sewage is common, which is easy to cause low carbon-nitrogen ratio (COD / TN) of sewage inflow, so that the existing treatment process is difficult to effectively treat the food industrial wastewater with low carbon-nitrogen ratio.

[0003] A2O sewage treatment process, also known as AAO process, is the abbreviation of the first letter of English Anaerobic-Anoxic-Oxic (anaerobic-anoxic-aerobic), which is a relatively mature secondary sewage treatment process with the function of simultaneous nitrogen and phosphorus removal, and is commonly used for secondary sewage treatment or tertiary sewage treatment. In the A2O process, the sewage first enters the anaerobic tank for anaerobic decomposition to remove part of the BOD, so that part of the nitrogen-containing compounds are converted into nitrogen gas (denitrification) and released; the anaerobic tank is connected with the return sludge, which releases phosphorus by using the polyphosphorus microorganisms (polyphosphorus bacteria, etc.) in the return sludge to meet the demand of bacteria for phosphorus. Then the sewage flows into the anoxic tank, and the denitrifying bacteria in the tank reduce the nitrate in the sewage that has not been decomposed into nitrogen gas as carbon source. Next, the sewage flows into the aerobic tank, and the NH3-N (ammonia nitrogen) in the water undergoes nitrification to generate nitrate, while the organic matter in the water is oxidized and decomposed to provide energy for the phosphorus-absorbing microorganisms, and the microorganisms absorb phosphorus from the water, which is enriched in the microorganisms and discharged from the system in the form of phosphorus-rich sludge after sedimentation and separation.

[0004] Therefore, the conventional A2O sewage treatment process has good nitrogen and phosphorus removal effect, but when the food industrial wastewater has low organic matter content and high total nitrogen content, it is difficult to meet the life metabolism activity demand of the water treatment microorganisms in the A2O process, which leads to the fact that the conventional A2O process cannot meet the treatment effect. Therefore, the applicant considers designing a sewage treatment system suitable for food industrial wastewater on the basis of the existing A2O process, so as to better improve the treatment effect of food industrial wastewater. UTILITY MODEL CONTENT

[0005] In view of the above prior art, the technical problem to be solved by the utility model is: how to provide a sewage treatment system for food industrial wastewater capable of efficiently treating food industrial wastewater with low carbon-nitrogen ratio without relying on external carbon source.

[0006] In order to solve the above technical problem, the utility model adopts the following technical scheme:

[0007] A sewage treatment system for food industrial wastewater, including anaerobic pool, primary anoxic pool and primary aerobic pool which are sequentially and serially arranged according to the water inlet direction, characterized in that the primary aerobic pool is sequentially and serially arranged with secondary anoxic pool, secondary aerobic pool, tertiary anoxic pool, tertiary aerobic pool and secondary sedimentation tank along the sewage flow direction, the secondary sedimentation tank is provided with sludge return pipeline at the bottom and returns to the anaerobic pool, and the primary anoxic pool, the primary aerobic pool, the secondary aerobic pool and the tertiary aerobic pool are respectively provided with aeration devices installed at the bottom.

[0008] In this way, the sewage mixes with the returned sludge after entering the anaerobic pool and the anaerobic phosphorus release reaction occurs, then the sewage enters the primary anoxic pool, the primary anoxic pool supplements a small amount of oxygen by the aeration device arranged therein to form an anoxic environment and carry out anoxic denitrification reaction, and then enters the aerobic pool to form an aerobic environment by a large amount of aeration to occur organic oxidation and nitrification reaction. Through the three times of anoxic and aerobic circulation, the sewage repeatedly carries out anoxic denitrification and aerobic nitrification reaction, which can better reduce the nitrogen pollutant content in the sewage; at the same time, it also does not need to rely on the secondary sedimentation tank to return the sewage to the anoxic tank to supplement nitrate like the traditional A2O process, avoiding the high nitrogen load in the single anoxic tank caused by the sewage return. The primary anoxic pool is connected after the anaerobic pool, so it needs to install an aeration device to supplement part of the oxygen to form an anoxic environment (the oxygen demand of the anoxic environment is higher than that of the anaerobic environment), but the secondary anoxic pool and the tertiary anoxic pool are connected at the outlet of the upper-stage aerobic pool, so they can directly form an anoxic environment.

[0009] In this way, the sewage treatment method realized by the system repeatedly carries out at least two cycles of the anoxic reaction and the aerobic reaction in the latter half of the traditional A2O process, so it can effectively reduce the nitrogen pollution concentration in the sewage through the multiple cycles of nitrification and denitrification reaction, and thus it is more suitable for the characteristics of the high total nitrogen pollution concentration of the food industrial wastewater and improves the treatment effect on the food industrial wastewater.

[0010] Further, the utility model also includes a water inlet pipe, and shunt pipes are installed in parallel on the water inlet pipe and are connected with the anaerobic pool, the secondary anoxic pool and the tertiary anoxic pool respectively, and water inlet control valves are arranged on the shunt pipes.

[0011] In this way, the influent control valve can control most of the proportion of sewage to be fed into the anaerobic tank, and a small proportion of sewage to be fed into the secondary and tertiary anoxic tanks (the proportion can be preferably controlled as 5:3:2), and fresh sewage can supplement the carbon source for the secondary and tertiary anoxic tanks, and assist the better removal of organic matter and the reduction of nitrogen pollutant content in the secondary and tertiary anoxic tanks. Specifically, the system is provided with three anoxic and aerobic sections, and seven reaction units in total including the anaerobic tank. The small proportion of sewage is introduced into the second and third anoxic and aerobic sections in proportion, which is beneficial to maintaining the normal life activities of the water treatment microorganisms in the two sections, and will not cause the influent to be introduced into the first section, so that the sludge in the first section has good activity, and the sludge in the last section has poor activity due to the limited carbon source concentration taken, which is beneficial to increasing the removal effect of the second and third anoxic and aerobic sections on pollutants. The denitrifying bacteria in the anoxic tank take the undecomposed carbon-containing organic matter in the sewage and the newly introduced carbon-containing organic matter as the carbon source, and reduce the nitrate produced in the upper aerobic tank to nitrogen gas and release, so that a good anoxic reaction treatment effect can be achieved without sewage backflow. Further, the treatment effect of the sewage is improved as a whole.

[0012] Further, the first anoxic tank and the first aerobic tank are separated by an active partition plate located therebetween, the active partition plate is arranged along the width direction of the tank body constituting the first anoxic tank and the first aerobic tank and can be moved and adjusted along the length direction of the tank body.

[0013] In this way, the volume ratio between the first anoxic tank and the first aerobic tank can be adjusted according to the water quality conditions of the influent and effluent, so as to ensure the denitrification and phosphorus removal effect of the biochemical tank under different conditions. Specifically, when the nitrogen concentration in the influent is high, the aerobic tank capacity can be increased by reducing the anoxic and aerobic volume ratio, so as to strengthen the treatment of the influent nitrogen pollutants by the aerobic nitrification reaction and improve the nitrogen treatment effect.

[0014] Further, the active partition plate has lug plates extending outwardly along the upper end surfaces of the two sides of the tank body, the lug plates are provided with bolt through holes, and the upper end surfaces of the two sides of the tank body are provided with bolt holes in an array along the length direction, and the lug plates are fixedly connected by being downwardly penetrated by bolts through the bolt through holes and the bolt holes.

[0015] In this way, the adjustment and fixation of the active partition plate are facilitated.

[0016] Further, the anaerobic tank is further provided with a flow measurement tank on one side, the effluent end of the anaerobic tank is communicated with the influent end of the first anoxic tank through an effluent pipe provided with a flow regulating valve, the other side of the effluent end of the anaerobic tank is communicated with the influent end of the flow measurement tank through an effluent pipe provided with a flow regulating valve, and the overflow effluent of the effluent end of the flow measurement tank is communicated with the influent end of the first anoxic tank through a flow measurement effluent pipe; the flow measurement tank is further provided with a phosphorus removal agent dosing device and a stirring device.

[0017] In this way, when the biochemical tank is faced with high phosphorus load and high total phosphorus requirement of the effluent, the partial effluent of the anaerobic tank can be controlled to enter the flow measurement tank first, in which a certain proportion of (ferrous) phosphorus removal agent is added by the phosphorus removal agent dosing device, stirred and then flocculated to remove phosphorus, and then the effluent is mixed into the primary anoxic tank to continue the subsequent reaction process, so as to control the final total phosphorus concentration of the effluent to meet the requirements of wastewater treatment and promote the recycling of phosphorus elements, so as to better meet the requirements of wastewater treatment. The flow measurement tank is connected after the anaerobic tank to avoid the influence of the drug on the anaerobic reaction, and the anaerobic tank only controls part of the effluent to remove phosphorus and controls the overflow effluent to enter the primary anoxic tank after phosphorus removal, which also avoids the influence of the drug on the anoxic reaction. Therefore, this method can maximize the reduction of the influence of the drug on the biochemical treatment process while ensuring the improvement of the phosphorus removal effect by the drug. When implemented, the dosing port of the phosphorus removal agent dosing device is connected to the inlet end of the flow measurement tank, the stirring device in the flow measurement tank is located near the inlet end, a group of inclined plates are arranged near the outlet end of the flow measurement tank to form an inclined plate sedimentation zone, the inclined plates in the inclined plate sedimentation zone are arranged at intervals and are fixed alternately on the left and right sides of the flow measurement tank, and the other side is spaced from the tank wall to allow the wastewater to flow back and forth. The outlet end of the flow measurement tank is provided with an overflow weir, and the overflow weir is connected to the effluent pipeline and the inlet end of the primary anoxic tank. In this way, the influence of the drug on the subsequent anoxic reaction is maximized. The phosphorus removal agent dosing device itself is a mature existing device, which can realize the metering of the phosphorus removal agent, and the specific structure is not described here.

[0018] Further, the bottom of the flow measurement tank is connected to the outside and provided with a flow measurement tank sludge discharge pipe. In this way, the settled flocculation sludge can be conveniently discharged to the outside.

[0019] Further, the anaerobic tank, the primary anoxic tank, the secondary anoxic tank and the tertiary anoxic tank are respectively provided with a stirring device.

[0020] In this way, the water treatment microorganisms and the wastewater can be fully mixed and contacted, and the reoxygenation in the tank can be realized to prevent short flow and other adverse phenomena, and the treatment efficiency of the biochemical tank for the wastewater can be increased. When implemented, the stirring device is preferably a submersible mixer to ensure better stirring effect.

[0021] Therefore, the above-mentioned wastewater treatment system can realize the following treatment steps:

[0022] S1, the wastewater flows into the anaerobic tank, the secondary anoxic tank and the tertiary anoxic tank through the inlet pipe in proportion, respectively, to occur anaerobic phosphorus release reaction and anoxic denitrification reaction;

[0023] S2, the wastewater flowing out of the anaerobic tank enters the primary anoxic tank and the side flow tank, respectively, to occur denitrification reaction in the primary anoxic tank and chemical phosphorus removal reaction with the ferrous phosphorus removal agent added by the phosphorus removal agent dosing device in the side flow tank;

[0024] S3, the supernatant flowing out of the lateral flow tank is discharged into the first stage anoxic tank through the water outlet pipe, the sludge flowing out of the lateral flow tank is discharged through the sludge discharge pipe, the sewage flowing out of the first stage anoxic tank enters the first stage aerobic tank, organic oxidation and nitrification reactions occur, the sewage flowing out of the first stage aerobic tank enters the second stage anoxic tank, denitrification reactions occur, the sewage flowing out of the second stage anoxic tank enters the second stage aerobic tank, organic oxidation and nitrification reactions occur, the sewage flowing out of the second stage aerobic tank enters the third stage anoxic tank, denitrification reactions occur, the sewage flowing out of the third stage anoxic tank enters the third stage aerobic tank, organic oxidation and nitrification reactions occur;

[0025] S4, the sewage flowing out of the third stage aerobic tank enters the secondary sedimentation tank for mud-water separation, the upper clear water is discharged through the water outlet pipe, and part of the sludge in the lower layer is discharged through the sludge return pipe into the anaerobic tank for recycling, and part of the sludge in the lower layer is discharged through the sludge discharge pipe at the bottom of the secondary sedimentation tank.

[0026] Therefore, the utility model has at least the following advantages and beneficial effects:

[0027] (1) Compared with the traditional A2O treatment process, in the utility model, a plurality of AO reaction tanks, a segmented water inlet system and a side flow tank chemical phosphorus removal system are additionally arranged, sewage is respectively introduced into the anaerobic tank, the second stage anoxic tank and the third stage anoxic tank according to a proportion, an anaerobic, anoxic and aerobic alternating environment is formed in the biochemical tank body, which is beneficial to short-cut nitrification and denitrification reactions, and total nitrogen and total phosphorus can be finally treated to reach the discharge standard.

[0028] (2) A stirring device and a ferrous phosphorus removal agent dosing device are arranged in the side flow tank, sewage introduced from the anaerobic tank is mixed with the ferrous phosphorus removal agent, the supernatant after precipitation is discharged into the first stage anoxic tank, the sludge after precipitation is discharged, the total phosphorus concentration in the sewage is reduced, and the sewage treatment standard is improved.

[0029] (3) The segmented water inlet system can adjust the water inlet proportion of the sewage in each tank in real time according to the water inlet quality and the water outlet quality standard, so as to improve the impact load capacity and treatment efficiency of the multi-stage AO process, for example, the water inlet proportion of the first stage anaerobic tank can be reduced to improve the TN removal effect of the multi-stage AO process.

[0030] (4) The partition plate between the first stage anoxic tank and the first stage aerobic tank is arranged to be movable, so as to adjust the volume ratio between the first stage anoxic tank and the first stage aerobic tank according to the water inlet and outlet quality, and the system can adjust the anoxic / aerobic volume ratio to ensure the denitrification and phosphorus removal effect of the multi-stage AO process under different conditions.

[0031] (5), the traditional building type of segmented water multi-stage AO system is improved into combined type of segmented water multi-stage AO system, so that the problem of high construction cost caused by building multiple structures can be effectively avoided, investment can be effectively saved; by omitting the internal reflux of nitrification liquid, the operation energy consumption of the biochemical pool can be reduced, conditions for more effectively carrying out denitrification reaction are provided, the denitrification and phosphorus removal effect of the biochemical pool is effectively improved, and the system is suitable for popularization in town and village areas where food processing industry is more. BRIEF DESCRIPTION OF DRAWINGS

[0032] Fig. 1 The figure is a structural schematic view of the sewage treatment system for food industrial wastewater.

[0033] Fig. 2 The figure is a structural schematic view of the sewage treatment system for food industrial wastewater. DETAILED DESCRIPTION

[0034] The utility model will be further explained in detail in combination with the drawings and examples.

[0035] An example of a sewage treatment system for food industrial wastewater is shown in the figure. Figs. 1-2 , comprising anaerobic pool 2, primary anoxic pool 3 and primary aerobic pool 4 that are sequentially connected in the water inlet direction, wherein the primary aerobic pool 4 is sequentially connected with secondary anoxic pool 5, secondary aerobic pool 6, tertiary anoxic pool 7, tertiary aerobic pool 8 and secondary sedimentation tank 9 in the forward direction of sewage flow, the secondary sedimentation tank 9 is provided with sludge return pipeline 13 at the bottom to return to the anaerobic pool, and the primary anoxic pool, the primary aerobic pool, the secondary aerobic pool and the tertiary aerobic pool are respectively provided with aeration device 15 at the bottom.

[0036] Thus, the sewage enters the anaerobic tank and mixes with the returned sludge to have an anaerobic phosphorus release reaction; then the sewage enters the first anoxic tank, the first anoxic tank relies on the aeration device arranged to supplement a small amount of oxygen to form an anoxic environment, to have an anoxic denitrification reaction, and then enters the aerobic tank to form an aerobic environment by a large amount of aeration to have an organic oxidation and nitrification reaction. Such three anoxic and aerobic cycles, the sewage repeatedly alternately has an anoxic denitrification and aerobic nitrification reaction, which can better reduce the nitrogen pollutant content in the sewage; at the same time, such a process also does not need to rely on the secondary sedimentation tank to return the sewage to the anoxic tank to supplement nitrate, avoiding the high nitrogen load in a single anoxic tank caused by the sewage return. The first anoxic tank is connected after the anaerobic tank, so an aeration device needs to be installed to supplement part of the oxygen to form an anoxic environment (the oxygen demand of the anoxic environment is higher than that of the anaerobic environment), but the second anoxic tank and the third anoxic tank are connected at the outlet end of the upper-stage aerobic tank, so an anoxic environment can be directly formed. In implementation, the bottom of the secondary sedimentation tank 9 is also externally provided with a secondary sedimentation tank sludge discharge pipe 16 to realize residual sludge discharge. The upper end of the secondary sedimentation tank 9 is also externally provided with a drain pipe 17 to realize external drainage.

[0037] The water inlet pipe 10 is provided with shunt pipes connected in parallel and connected with the anaerobic tank, the second anoxic tank and the third anoxic tank in communication, and the shunt pipes are provided with water inlet control valves.

[0038] Thus, the water inlet control valves can control most of the proportion of the sewage to enter the anaerobic tank, and a small proportion of the sewage to enter the second anoxic tank and the third anoxic tank (the proportion can be preferably controlled at 5:3:2), and the fresh sewage can supplement the carbon source for the second anoxic tank and the third anoxic tank to better achieve the removal of organic matter and the reduction of the nitrogen pollutant content.

[0039] The first anoxic tank and the first aerobic tank are separated by an active partition plate 14 located therebetween, the active partition plate is arranged along the width direction of the tank body constituting the first anoxic tank and the first aerobic tank and can be moved and adjusted along the length direction of the tank body.

[0040] Thus, the volume ratio between the first anoxic tank and the first aerobic tank can be adjusted according to the water quality conditions to ensure the denitrification and phosphorus removal effect of the biochemical tank under different conditions. Specifically, when the nitrogen concentration in the influent is high, the aerobic tank capacity can be increased by reducing the anoxic-aerobic volume ratio, thereby strengthening the treatment of the influent nitrogen pollutants by the aerobic nitrification reaction and improving the nitrogen treatment effect.

[0041] The active partition plate 14 has ear plates 21 extending outwardly along the upper end surfaces of the two sides of the tank body, the ear plates 21 are provided with bolt through holes, the upper end surfaces of the two sides of the tank body are provided with bolt holes 23 in an array along the length direction, and the ear plates are fixedly connected by the bolts 22 passing through the bolt through holes and the bolt holes downwardly.

[0042] Thus, it is convenient to adjust and fix the movable partition.

[0043] The anaerobic tank is connected to the first-stage anoxic tank through an outlet pipe with a flow regulating valve, and the outlet pipe is connected to the water inlet end of the first-stage anoxic tank. The outlet end of the anaerobic tank is connected to the water inlet end of the measuring tank through an outlet pipe with a flow regulating valve, and the outlet pipe is connected to the water inlet end of the first-stage anoxic tank. The overflow outlet of the measuring tank is connected to the water inlet end of the first-stage anoxic tank through a measuring outlet pipe. A phosphorus removal agent feeding device and a stirring device are arranged in the measuring tank.

[0044] Thus, when the biochemical tank faces a high phosphorus load and a high total phosphorus requirement, part of the outlet water of the anaerobic tank can be controlled to enter the measuring tank first. In the measuring tank, a certain proportion of (ferrous) phosphorus removal agent is added by the phosphorus removal agent feeding device and stirred to achieve flocculation and phosphorus removal, and then the outlet water is mixed into the first-stage anoxic tank for subsequent reaction process to control the final outlet water total phosphorus concentration to meet the requirements of wastewater treatment and promote the recycling of phosphorus elements. The measuring tank is connected to the anaerobic tank to avoid the influence of the drug on the anaerobic reaction. The anaerobic tank only controls part of the outlet water for phosphorus removal and controls the overflow outlet water to enter the first-stage anoxic tank after phosphorus removal, which also avoids the influence of the drug on the anoxic reaction. Therefore, this method can maximize the reduction of the influence of the drug on the biochemical treatment process while ensuring the improvement of the phosphorus removal effect by the drug. In implementation, the dosing port of the phosphorus removal agent feeding device is connected to the water inlet end of the measuring tank, the stirring device in the measuring tank is arranged near the water inlet end, a group of inclined plates are arranged near the outlet end of the measuring tank to form an inclined plate sedimentation zone, the inclined plates in the inclined plate sedimentation zone are arranged at intervals and are fixed alternately on the left and right sides of the measuring tank, and a space is left between the other side and the tank wall for the back-and-forth flow of sewage. An overflow weir is arranged at the outlet end of the measuring tank, and the overflow weir is connected to the outlet pipe and the water inlet end of the first-stage anoxic tank. Thus, the influence of the drug on the subsequent anoxic reaction is maximized. The phosphorus removal agent feeding device itself is a mature existing device that can realize the metering addition of phosphorus removal agent, and the specific structure is not described here.

[0045] The bottom of the measuring tank is connected to the measuring tank sludge discharge pipe 12. Thus, it is convenient to discharge the flocculated sludge.

[0046] The anaerobic tank, the first-stage anoxic tank, the second-stage anoxic tank, and the third-stage anoxic tank are respectively provided with a stirring device.

[0047] Thus, it is convenient to discharge the flocculated sludge.

[0048] The sewage treatment system can realize the following treatment steps:

[0049] S1, the sewage flows into the anaerobic tank, the secondary anoxic tank and the tertiary anoxic tank in proportion through the inlet pipe, respectively, to generate anaerobic phosphorus release reaction and anoxic denitrification reaction;

[0050] S2, the sewage flowing out of the anaerobic tank enters the primary anoxic tank and the side flow tank, respectively, to generate denitrification reaction in the primary anoxic tank and chemical phosphorus removal reaction in the side flow tank by mixing with ferrous phosphorus removal agent added by the phosphorus removal agent adding device;

[0051] S3, the supernatant flowing out of the side flow tank is discharged into the primary anoxic tank through the outlet pipe, the sludge flowing out of the side flow tank is discharged through the sludge discharge pipe, the sewage flowing out of the primary anoxic tank enters the primary aerobic tank to generate organic oxidation and nitrification reaction, the sewage flowing out of the primary aerobic tank enters the secondary anoxic tank to generate denitrification reaction, the sewage flowing out of the secondary anoxic tank enters the secondary aerobic tank to generate organic oxidation and nitrification reaction, the sewage flowing out of the secondary aerobic tank enters the tertiary anoxic tank to generate denitrification reaction, and the sewage flowing out of the tertiary anoxic tank enters the tertiary aerobic tank to generate organic oxidation and nitrification reaction;

[0052] S4, the sewage flowing out of the tertiary aerobic tank enters the secondary sedimentation tank to separate the sludge and water, the upper clear water is discharged through the outlet pipe, and part of the lower sludge is discharged into the anaerobic tank through the sludge reflux pipe for recycling, and part of the lower sludge is discharged through the sludge discharge pipe at the bottom of the secondary sedimentation tank.

Claims

1. A sewage treatment system for food industry wastewater, comprising an anaerobic tank, a first anoxic tank and a first aerobic tank which are arranged in series in the direction of water inflow, characterized in that, The primary aerobic tank is sequentially connected with a secondary anoxic tank, a secondary aerobic tank, a tertiary anoxic tank, a tertiary aerobic tank and a secondary sedimentation tank in sequence along the sewage flow direction, the secondary sedimentation tank is provided with a sludge return pipeline at the bottom to return to the anaerobic tank, and the primary anoxic tank, the primary aerobic tank, the secondary aerobic tank and the tertiary aerobic tank are respectively provided with an aeration device installed at the bottom; The water inlet pipe is provided with shunt pipes connected with the anaerobic tank, the secondary anoxic tank and the tertiary anoxic tank in parallel, and the shunt pipes are provided with water inlet control valves for controlling the majority of sewage to be fed into the anaerobic tank and a small proportion of sewage to be fed into the secondary anoxic tank and the tertiary anoxic tank respectively, so as to supplement the carbon source for the secondary anoxic tank and the tertiary anoxic tank, remove organic matter and reduce the content of nitrogen pollutants.

2. The sewage treatment system for food industry wastewater as claimed in claim 1, wherein, The primary anoxic tank and the primary aerobic tank are separated by an active partition plate located between the two, the active partition plate is arranged along the width direction of the tank body constituting the primary anoxic tank and the primary aerobic tank and can be moved and adjusted along the length direction of the tank body.

3. The sewage treatment system for food industry wastewater as claimed in claim 2, wherein, The upper end of the active partition plate is provided with ear plates extending outward transversely along the upper end surfaces of the two sides of the tank body, the ear plates are provided with bolt through holes, the upper end surfaces of the two sides of the tank body are provided with bolt holes in an array along the length direction, and the ear plates are fixedly connected by being downwardly penetrated through the bolt through holes and the bolt holes.

4. The sewage treatment system for food industry wastewater as claimed in claim 1, wherein, The anaerobic tank is further provided with a side flow tank on one side, the water outlet end of the anaerobic tank is communicated with the water inlet end of the primary anoxic tank through a water outlet pipe provided with a flow regulating valve, the other side of the water outlet end of the anaerobic tank is communicated with the water inlet end of the side flow tank through a water outlet pipe provided with a flow regulating valve, and the water outlet end of the side flow tank is communicated with the water inlet end of the primary anoxic tank after overflow.

5. The sewage treatment system for food industry wastewater as claimed in claim 4, wherein, The bottom of the side flow tank is connected with a side flow tank sludge discharge pipe.

6. The sewage treatment system for food industry wastewater as claimed in claim 1, wherein, The anaerobic tank, the primary anoxic tank, the secondary anoxic tank and the tertiary anoxic tank are respectively provided with a stirring device.

Images