A starch sugar production wastewater treatment system and process

Abstract

The present application relates to a kind of starch sugar production wastewater treatment system and process, including pretreatment unit, composite unit, gradient load biochemical treatment unit and tail processing unit;Pretreatment unit includes sand trap and water collecting tank in communication;Composite unit includes shallow air floatation device, adjusting tank and internal circulation anaerobic reactor in turn, shallow air floatation device is connected water collecting tank;Gradient load biochemical treatment unit includes adsorption pool, regeneration pool, sedimentation tank, dissolved oxygen rapid elimination pool, anaerobic tank and aerobic tank in turn, adsorption pool is connected internal circulation anaerobic reactor;Tail processing unit includes secondary sedimentation tank.This scheme is stable and efficient operation.At the same time, by gradient load biochemical treatment unit high-low load section setting and sludge composite anaerobic, reduce the aeration quantity of biochemical treatment unit, recover organic matter ability and reduce sludge discharge, to reduce operating electricity and sludge treatment cost, and the required supporting large equipment is relatively less, reduce investment cost.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology in starch sugar production, and in particular to a wastewater treatment system and process for starch sugar production. Background Technology

[0002] Maltose is produced from rice starch. The main production processes include crushing, soaking, grinding, filtering, liquefaction, saccharification, decolorization, ion exchange, and drying. Water pollution sources mainly come from rice washing and soaking wastewater, secondary filter press wastewater, ion exchange wastewater, pre-saccharification cooling water, drum washing wastewater, and evaporation wastewater. The main pollutants are suspended solids, chemical oxygen demand (COD), biochemical oxygen demand (BOD), ammonia nitrogen, total nitrogen, and total phosphorus. The typical water quality of starch saccharide wastewater is: dichromate index (COD). cr =3000~8000mg / L, biological oxygen demand (BOD5) =1500~5000mg / L, suspended solids concentration (SS) =500~1000mg / L, total nitrogen (TN) =40~100mg / L, ammonia nitrogen content index (NH3-N) =15~30mg / L, total phosphorus (TP) =5~20mg / L, pH =4~5, water temperature ≤42℃.

[0003] The commonly used treatment process for starch sugar production wastewater, as described in the wastewater recovery method for starch sugar production disclosed in patent CN102863096B, involves the wastewater undergoing neutralization, flocculation sedimentation, plate and frame filtration for slag removal, granular activated carbon decolorization, bag filter fine filtration, hollow fiber membrane ultrafiltration, and reverse osmosis membrane filtration. This method can treat 60% to 70% of the wastewater. However, this patent requires a large amount of large-scale equipment for implementation, resulting in relatively high investment costs. Furthermore, impurities in the wastewater still require further treatment after sedimentation and filtration. Summary of the Invention

[0004] In view of this, it is necessary to provide a starch sugar production wastewater treatment system and process to solve the technical problem that the existing starch sugar production wastewater treatment process requires a large number of supporting filtration equipment and has a relatively high investment cost.

[0005] This invention provides a starch sugar production wastewater treatment system, which includes:

[0006] The pretreatment unit includes a grit chamber and a collection tank connected to each other. The grit chamber is used to collect production wastewater and transport it to the collection tank.

[0007] The composite unit includes a shallow air flotation device, an equalization tank, and an internal circulation anaerobic reactor connected in sequence. The shallow air flotation device is connected to the water collection tank and the treated solution is transported to the internal circulation anaerobic reactor via the equalization tank.

[0008] A tiered loading biochemical treatment unit includes an adsorption tank, a regeneration tank, a sedimentation tank, a dissolved oxygen rapid elimination tank, an anaerobic tank, and an aerobic tank connected in sequence. The adsorption tank is connected to the internal circulation anaerobic reactor to receive the solution transported from the internal circulation anaerobic reactor and sequentially transport it to the regeneration tank, the sedimentation tank, the dissolved oxygen rapid elimination tank, the anaerobic tank, and the aerobic tank. The bottom of the sedimentation tank is also connected to the internal circulation anaerobic reactor, allowing some of the sludge at the bottom of the sedimentation tank to enter the internal circulation anaerobic reactor.

[0009] The tailings treatment unit includes a secondary sedimentation tank connected to the aerobic tank, which is used to receive the solution transported from the aerobic tank.

[0010] Optionally, the outlet of the water collection tank is connected to the shallow air flotation device, the internal circulation anaerobic reactor, the regeneration tank, and the dissolved oxygen rapid elimination tank, respectively.

[0011] Optionally, the bottom of the sedimentation tank is connected to the adsorption tank, so that the sludge located at the bottom of the sedimentation tank can be partially returned to the adsorption tank.

[0012] Optionally, the bottom of the secondary sedimentation tank is connected to the dissolved oxygen rapid elimination tank, so that the sludge located at the bottom of the secondary sedimentation tank can be returned to the dissolved oxygen rapid elimination tank.

[0013] Optionally, the starch sugar production wastewater treatment system further includes a sludge storage tank, which is connected to the bottom of the secondary sedimentation tank and is used to store sludge transported from the secondary sedimentation tank.

[0014] Optionally, the sludge storage tank is also connected to the shallow air flotation device and the internal circulation anaerobic reactor, respectively, for storing sludge transported from the shallow air flotation device and the internal circulation anaerobic reactor.

[0015] Optionally, the sludge in the sludge storage tank can also be partially recycled back to the internal circulation anaerobic reactor.

[0016] Optionally, the tailings treatment unit further includes a phosphorus removal reaction tank and a third sedimentation tank connected together. The phosphorus removal reaction tank is connected to the second sedimentation tank to remove phosphorus from the solution transported from the second sedimentation tank.

[0017] The bottom of the three sedimentation tank is connected to the sludge storage tank, so as to transport the sludge deposited at the bottom of the three sedimentation tank to the sludge storage tank.

[0018] Optionally, a screen is provided at the inlet of the sedimentation tank.

[0019] Furthermore, the present invention also provides a process for treating starch sugar production wastewater, used in the starch sugar production wastewater treatment system described in any of the above claims, wherein the starch sugar production wastewater treatment process includes the following steps:

[0020] The production wastewater is sequentially transported to the sedimentation tank, the collection tank and the shallow air flotation device, and then transported to the equalization tank.

[0021] After the production wastewater enters the equalization tank for homogenization and equalization, it is mixed with a portion of the sludge returned from the sedimentation tank, and then sequentially transported to the internal circulation anaerobic reactor, the adsorption tank, the regeneration tank, the sedimentation tank, the dissolved oxygen rapid elimination tank, the anaerobic tank, the aerobic tank, and the secondary sedimentation tank.

[0022] The sludge produced by the shallow air flotation device, the periodic sludge discharge from the internal circulation anaerobic reactor, and the residual activated sludge produced by the secondary sedimentation tank are dewatered by a sludge dewatering device, and the dewatered sludge cake is periodically transported off-site for disposal.

[0023] Compared with existing technologies, the starch sugar production wastewater treatment system provided by this invention sequentially passes through a grit chamber, a collection tank, a shallow air flotation device, an equalization tank, an internal circulation anaerobic reactor, an adsorption tank, a regeneration tank, a sedimentation tank, a dissolved oxygen rapid elimination tank, an anaerobic tank, an aerobic tank, and a secondary sedimentation tank. The shallow air flotation process more effectively removes light suspended solids and total phosphorus (TP) from the wastewater. Furthermore, the internal circulation anaerobic reactor and the tiered loading biochemical treatment process consisting of an adsorption tank, a regeneration tank, a sedimentation tank, a dissolved oxygen rapid elimination tank, an anaerobic tank, and an aerobic tank utilize microorganisms to remove organic matter, NH3-N, total nitrogen (TN), and TP, resulting in stable and efficient operation. Simultaneously, by setting high and low load segments in the tiered loading biochemical treatment units and using sludge-based composite anaerobic treatment, the aeration volume of the biochemical treatment units is reduced, improving organic matter recovery capacity and reducing sludge discharge, thereby lowering operating electricity costs and sludge treatment costs. Moreover, the required large-scale equipment is relatively small, reducing investment costs.

[0024] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it according to the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. Specific embodiments of the present invention are given in detail in the following embodiments and their accompanying drawings. Attached Figure Description

[0025] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings:

[0026] Figure 1This is a schematic diagram of the process flow of an embodiment of the starch sugar production wastewater treatment system provided by the present invention.

[0027] Explanation of reference numerals in the attached figures:

[0028] 100. Starch Sugar Production Wastewater Treatment System; 1. Pretreatment Unit; 2. Shallow Air Flotation Device; 3. Equalization Tank; 4. Internal Circulation Anaerobic Reactor; 5. Adsorption Tank; 6. Regeneration Tank; 61. Sedimentation Tank; 7. Dissolved Oxygen Rapid Removal Tank; 8. Anaerobic Tank; 9. Aerobic Tank; 10. Secondary Sedimentation Tank; 11. Phosphorus Removal Reactor; 12. Tertiary Sedimentation Tank; 13. Sludge Storage Tank. Detailed Implementation

[0029] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which form part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0030] Please see Figure 1 This starch sugar production wastewater treatment system 100 includes a pretreatment unit 1, a composite unit, a cascaded load biochemical treatment unit, and a tailings treatment unit. The pretreatment unit 1 includes a grit chamber and a collection tank connected together. The grit chamber is used to collect the production wastewater and transport it to the collection tank. The composite unit includes a shallow air flotation device 2, a regulating tank 3, and an internal circulation anaerobic reactor 4 connected in sequence. The shallow air flotation device 2 is connected to the collection tank, and the treated solution is transported to the internal circulation anaerobic reactor 4 via the regulating tank 3. The cascaded load biochemical treatment unit... The load biochemical treatment unit includes an adsorption tank 5, a regeneration tank 6, a sedimentation tank 61, a dissolved oxygen rapid elimination tank 7, an anaerobic tank 8, and an aerobic tank 9 connected in sequence. The adsorption tank 5 is connected to the internal circulation anaerobic reactor 4 to receive the solution transported from the internal circulation anaerobic reactor 4 and to transport it in sequence to the regeneration tank 6, sedimentation tank 61, dissolved oxygen rapid elimination tank 7, anaerobic tank 8, and aerobic tank 9. The tailings treatment unit includes a secondary sedimentation tank 10, which is connected to the aerobic tank 9 to receive the solution transported from the aerobic tank 9.

[0031] The starch sugar production wastewater treatment system 100 provided by this invention sequentially passes through a grit chamber, a collection tank, a shallow air flotation device 2, an equalization tank 3, an internal circulation anaerobic reactor 4, an adsorption tank 5, a regeneration tank 6, a sedimentation tank 61, a dissolved oxygen rapid elimination tank 7, an anaerobic tank 8, an aerobic tank 9, and a secondary sedimentation tank 10. It employs a shallow air flotation process to more effectively remove light suspended solids and total phosphorus (TP) from the wastewater. Furthermore, it utilizes a tiered loading biochemical treatment process consisting of the internal circulation anaerobic reactor 4 and the adsorption tank 5, regeneration tank 6, sedimentation tank 61, dissolved oxygen rapid elimination tank 7, anaerobic tank 8, and aerobic tank 9. This process uses microorganisms to remove organic matter, NH3-N, total nitrogen (TN), and TP, resulting in stable and efficient operation. Simultaneously, by setting high and low load segments in the tiered loading biochemical treatment units and using sludge-based composite anaerobic treatment, the aeration volume of the biochemical treatment units is reduced, improving organic matter recovery capacity and reducing sludge discharge, thereby lowering operating electricity costs and sludge treatment costs. Moreover, it requires relatively fewer large-scale supporting equipment, reducing investment costs.

[0032] It should be noted that the shallow air flotation device 2 introduces air into the water in the form of microbubbles, causing the microbubbles to adhere to suspended particles in the water, forming a three-phase mixed system of water, air, and particles. After the particles adhere to the bubbles, their density is less than that of water, so they float to the surface, forming a scum layer that separates from the water. The dissolved air method is pressurized jet. The internal circulation anaerobic reactor 4, also known as the IC anaerobic reactor, is similar to a system consisting of two layers of upflow anaerobic sludge blanket (UASB) reactors connected in series. It consists of two reaction chambers, upper and lower. Wastewater flows from bottom to top in the reactor, pollutants are adsorbed and degraded by bacteria, and the purified water flows out from the top of the reactor.

[0033] In addition, the main function of adsorption tank 5 is to adsorb, precipitate, and oxidize pollutants in water through various physical, chemical, and biological methods, thereby purifying water quality and protecting the environment; the function of regeneration tank 6 is to regenerate the sludge after sewage treatment so as to better utilize its biological quality and active bacteria.

[0034] Furthermore, the outlet of the collection tank is connected to the shallow air flotation device 2, the internal circulation anaerobic reactor 4, the regeneration tank 6, and the dissolved oxygen rapid elimination tank 7, respectively. In this embodiment, the effluent from the collection tank can be pumped into the shallow air flotation device 2, the internal circulation anaerobic reactor 4, the regeneration tank 6, and the dissolved oxygen rapid elimination tank 7, respectively. It should be noted that the dissolved oxygen rapid elimination tank 7 fully consumes and utilizes the dissolved oxygen in the delivered sludge mixture, and the sludge provides a carbon source for denitrification.

[0035] Furthermore, the bottom of the sedimentation tank 61 is connected to the adsorption tank 5, allowing some of the sludge at the bottom of the sedimentation tank 61 to be returned to the adsorption tank 5. Simultaneously, the bottom of the sedimentation tank 61 is also connected to the internal circulation anaerobic reactor 4, allowing some of the sludge at the bottom of the sedimentation tank 61 to enter the internal circulation anaerobic reactor 4, thereby improving purification efficiency. This allows sludge rich in organic matter to be returned to the IC anaerobic reactor, increasing the system's biogas production while reducing the system's sludge production.

[0036] Furthermore, the bottom of the secondary sedimentation tank 10 is connected to the dissolved oxygen rapid elimination tank 7, allowing the sludge at the bottom of the secondary sedimentation tank 10 to be returned to the dissolved oxygen rapid elimination tank 7. Specifically, in this embodiment, the sludge return ratio from the secondary sedimentation tank 10 to the dissolved oxygen rapid elimination tank 7 is adjusted to 100%–200%, which is higher than the 80%–100% of the conventional AO (anoxic / aerobic) process. In addition, it should be noted that, for ease of understanding, in the following description, the adsorption tank 5, the regeneration tank 6, and the sedimentation tank 61 are collectively referred to as the adsorption-regeneration zone (AR), and the dissolved oxygen rapid elimination tank 7, the anaerobic tank 8, and the aerobic tank 9 are collectively referred to as the nitrogen and phosphorus enhanced removal zone (BO); wherein, the AR (adsorption-regeneration zone) operates at high load and forms an ARBO cascade load biochemical treatment unit with the BO (nitrogen and phosphorus enhanced removal zone).

[0037] Furthermore, the starch sugar production wastewater treatment system 100 also includes a sludge storage tank 13, which is connected to the bottom of the secondary sedimentation tank 10 and is used to store the sludge transported from the secondary sedimentation tank 10. Simultaneously, the sludge storage tank 13 is also connected to the shallow air flotation device 2 and the internal circulation anaerobic reactor 4, respectively, to store the sludge transported from these devices. In addition, the sludge in the sludge storage tank 13 can also be partially recycled back to the internal circulation anaerobic reactor 4. In this embodiment, part of the activated sludge produced in the secondary sedimentation tank 10 is recycled to the dissolved oxygen rapid removal zone, and the remaining sludge is discharged to the sludge storage tank 13. At the same time, the sludge produced by the shallow air flotation device 2 can also be discharged into the sludge storage tank 13. The sludge produced by the IC anaerobic reactor can be periodically discharged to the sludge storage tank 13, or the sludge in the sludge storage tank 13 can be recycled back to the IC anaerobic reactor. Specifically, the sludge in sludge storage tank 13 is partially returned to the IC anaerobic reactor, and the remaining part is sent to the sludge dewatering system for dewatering treatment. The dewatered sludge cake is transported off-site for disposal on a regular basis.

[0038] Furthermore, the tailings treatment unit also includes a connected phosphorus removal reaction tank 11 and a tertiary settling tank 12. The phosphorus removal reaction tank 11 is connected to the secondary settling tank 10 to remove phosphorus from the solution transported from the secondary settling tank 10. The bottom of the tertiary settling tank 12 is connected to a sludge storage tank 13 to transport the sludge deposited at its bottom to the sludge storage tank 13. In this embodiment, the tailings treatment unit further includes a phosphorus removal reaction tank 11 and a tertiary settling tank 12 to further improve the phosphorus removal effect. The chemical sludge generated in the tertiary settling tank 12 is discharged to the sludge storage tank 13 for storage, and then sent to a sludge dewatering device for dewatering treatment. The dewatered sludge cake is periodically transported off-site for disposal. It should be understood that the phosphorus removal reaction includes two necessary processes: first, converting soluble phosphorus-containing substances in the wastewater into insoluble particulate form; and then removing the particulate solids to achieve the purpose of phosphorus removal from the wastewater.

[0039] Furthermore, a bar screen is installed at the inlet of the grit chamber. In this embodiment, a bar screen is installed at the inlet of the grit chamber and is used in conjunction with pretreatment facilities such as the shallow air flotation device 2 to remove larger suspended solids, gravel, and suspended solids with lower specific gravity from the wastewater.

[0040] Based on the above embodiments, the process of the starch sugar production wastewater treatment system 100 provided by the present invention is as follows: bar screen → grit chamber → collection tank → shallow air flotation device 2 → equalization tank 3 → IC anaerobic reactor → ARBO graded load biochemical treatment unit → secondary sedimentation tank 10 → phosphorus removal reaction tank 11 → tertiary sedimentation tank 12. The bar screen, grit chamber, and shallow air flotation process are used to pretreat the incoming water, removing suspended solids from the wastewater, resulting in a smaller footprint and higher removal efficiency. Furthermore, the "IC anaerobic reactor + graded ARBO graded load biochemical process" is used as the main process, effectively removing organic matter while efficiently removing nitrogen and phosphorus, reducing the volume of the biochemical tank, lowering investment and operating energy consumption, and simultaneously providing multiple functions such as sludge reduction and increased energy recovery.

[0041] In purifying wastewater, the present invention provides a starch sugar production wastewater treatment process comprising the following steps:

[0042] The production wastewater is sequentially transported to the sedimentation tank, the collection tank and the shallow air flotation device 2, and then transported to the equalization tank 3.

[0043] After the production wastewater enters the equalization tank 3 for homogenization and equalization, the sludge returned from the sedimentation tank 61 is mixed and then sequentially transported to the internal circulation anaerobic reactor 4, adsorption tank 5, regeneration tank 6, sedimentation tank 61, dissolved oxygen rapid elimination tank 7, anaerobic tank 8, aerobic tank 9 and secondary sedimentation tank 10.

[0044] The sludge produced by the shallow air flotation device 2, the periodic sludge discharge from the internal circulation anaerobic reactor 4, and the residual activated sludge produced by the secondary sedimentation tank 10 are dewatered by the sludge dewatering equipment, and the dewatered sludge cake is transported off-site for disposal on a regular basis.

[0045] The specific implementation process is as follows:

[0046] (1) Pretreatment facilities such as screens, grit chambers and shallow air flotation are installed at the front end to remove larger suspended solids, gravel and smaller suspended solids in the wastewater respectively.

[0047] (2) After the wastewater enters the equalization tank 3 for homogenization and equalization, the sludge from the ARBO cascade load biochemical treatment unit is mixed and enters the downstream IC anaerobic reactor. The IC anaerobic reactor decomposes most of the organic matter in the wastewater and produces a large amount of biogas. The biogas can be recycled or burned in a flare.

[0048] (3) After anaerobic treatment in the IC anaerobic reactor, the wastewater enters the ARBO cascade load biochemical treatment unit to fully degrade BOD, NH3-N, TN and TP in the wastewater.

[0049] (4) The sludge produced by shallow air flotation, the periodic sludge discharge from the IC anaerobic reactor, the residual activated sludge produced by the secondary sedimentation tank 10, and the sludge produced by the tertiary sedimentation tank 12 are sent to the sludge storage tank 13 for storage, and then sent to the sludge dewatering equipment for dewatering treatment. The dewatered sludge cake is periodically transported off-site for disposal.

[0050] Specifically, larger suspended solids and heavier pollutants such as sand and gravel in the wastewater are removed by screens and grit chambers, and then light suspended solids in the wastewater are further removed by shallow air flotation.

[0051] The treatment process employs an "IC anaerobic reactor + ARBO cascade loading biological treatment process." Most organic pollutants in the wastewater are removed by the IC anaerobic reactor before entering the ARBO cascade loading biological treatment process. The ARBO cascade loading biological treatment unit is divided into an AR (adsorption-regeneration zone) and a BO (nitrogen and phosphorus enhanced removal zone). The AR zone primarily utilizes biological adsorption-regeneration, operating at a high load, and provides excellent buffering against shock loads on water quality and quantity. Simultaneously, a sludge return system is installed in the AR zone to return organic-rich sludge to the IC anaerobic reactor, where it undergoes anaerobic treatment, increasing biogas production and reducing sludge volume and treatment costs. The AR (adsorption-regeneration zone) operates at a high load, reducing the organic load entering the BO (nitrogen and phosphorus enhanced removal zone), effectively preventing the inhibition of NH3-N nitrification by high organic loads, ensuring stable operating conditions for nitrifying bacteria in this zone, improving the removal efficiency of ammonia nitrogen and total phosphorus, while also saving tank volume and aeration air volume, reducing investment and operating costs.

[0052] Furthermore, the BO zone is equipped with a rapid dissolved oxygen removal tank 7, which has the function of simultaneous nitrogen and phosphorus removal, with a retention time of 4 to 6 hours; the sludge return ratio from the secondary sedimentation tank 10 to the BO zone is adjusted to 100% to 200%, which is higher than the 80% to 100% of the conventional AO process.

[0053] In addition, the water can automatically bypass the shallow air flotation device 2 and enter the IC anaerobic reactor and ARBO cascade load biochemical treatment unit according to the water temperature. This effectively utilizes the IC anaerobic reactor to reduce the amount of sludge discharged from the shallow air flotation, while also effectively utilizing the influent temperature to reduce the heating energy of the IC anaerobic reactor and supplement the carbon source for the denitrification reaction of the ARBO cascade load biochemical treatment unit.

[0054] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A wastewater treatment system for starch sugar production, characterized in that, It includes: The pretreatment unit includes a grit chamber and a collection tank connected to each other. The grit chamber is used to collect production wastewater and transport it to the collection tank. The composite unit includes a shallow air flotation device, an equalization tank, and an internal circulation anaerobic reactor connected in sequence. The shallow air flotation device is connected to the water collection tank and the treated solution is transported to the internal circulation anaerobic reactor via the equalization tank. The cascaded loading biochemical treatment unit includes an adsorption tank, a regeneration tank, a sedimentation tank, a dissolved oxygen rapid elimination tank, an anaerobic tank, and an aerobic tank connected in sequence. The adsorption tank is connected to the internal circulation anaerobic reactor and is used to collect the solution transported from the internal circulation anaerobic reactor, which is then sequentially transported to the regeneration tank, the sedimentation tank, the dissolved oxygen rapid elimination tank, the anaerobic tank, and the aerobic tank. The bottom of the sedimentation tank is connected to the internal circulation anaerobic reactor, allowing some of the sludge at the bottom of the sedimentation tank to enter the internal circulation anaerobic reactor. The adsorption tank, regeneration tank, and sedimentation tank constitute an adsorption-regeneration zone, and the dissolved oxygen rapid elimination tank, anaerobic tank, and aerobic tank constitute a nitrogen and phosphorus enhanced removal zone. as well as, The tailings treatment unit includes a secondary sedimentation tank, which is connected to the aerobic tank and is used to receive the solution transported from the aerobic tank. The outlet of the water collection tank is connected to the shallow air flotation device, the internal circulation anaerobic reactor, the regeneration tank, and the dissolved oxygen rapid elimination tank, respectively. The bottom of the sedimentation tank is connected to the adsorption tank, so that the sludge located at the bottom of the sedimentation tank can be partially returned to the adsorption tank. The bottom of the secondary sedimentation tank is connected to the dissolved oxygen rapid elimination tank, so that the sludge located at the bottom of the secondary sedimentation tank can be returned to the dissolved oxygen rapid elimination tank. The sludge return ratio from the secondary sedimentation tank to the dissolved oxygen rapid elimination tank is 100%~200%.

2. The starch sugar production wastewater treatment system according to claim 1, characterized in that, The outlet of the water collection tank is connected to the shallow air flotation device, the internal circulation anaerobic reactor, the regeneration tank, and the dissolved oxygen rapid elimination tank, respectively.

3. The starch sugar production wastewater treatment system according to claim 1, characterized in that, A grating is installed at the inlet of the sedimentation tank.

4. The starch sugar production wastewater treatment system according to claim 3, characterized in that, The starch sugar production wastewater treatment system also includes a sludge storage tank, which is connected to the bottom of the secondary sedimentation tank and is used to store the sludge transported from the secondary sedimentation tank.

5. The starch sugar production wastewater treatment system according to claim 4, characterized in that, The sludge storage tank is also connected to the shallow air flotation device and the internal circulation anaerobic reactor, respectively, for storing sludge transported from the shallow air flotation device and the internal circulation anaerobic reactor.

6. The starch sugar production wastewater treatment system according to claim 5, characterized in that, The sludge in the sludge storage tank can also be partially recycled back to the internal circulation anaerobic reactor.

7. The starch sugar production wastewater treatment system according to claim 4, characterized in that, The tailings treatment unit also includes a phosphorus removal reaction tank and a third sedimentation tank that are connected to each other. The phosphorus removal reaction tank is connected to the second sedimentation tank and is used to remove phosphorus from the solution transported from the second sedimentation tank. The bottom of the three sedimentation tank is connected to the sludge storage tank, so as to transport the sludge deposited at the bottom of the three sedimentation tank to the sludge storage tank.

8. A process for treating wastewater from starch sugar production, used in the wastewater treatment system for starch sugar production as described in any one of claims 1 to 7, characterized in that, The process for treating wastewater from starch sugar production includes the following steps: The production wastewater is sequentially transported to the sedimentation tank, the collection tank and the shallow air flotation device, and then transported to the equalization tank. After the production wastewater enters the equalization tank for homogenization and equalization, it is mixed with a portion of the sludge returned from the sedimentation tank, and then sequentially transported to the internal circulation anaerobic reactor, the adsorption tank, the regeneration tank, the sedimentation tank, the dissolved oxygen rapid elimination tank, the anaerobic tank, the aerobic tank, and the secondary sedimentation tank. The sludge produced by the shallow air flotation device, the periodic sludge discharge from the internal circulation anaerobic reactor, and the residual activated sludge produced by the secondary sedimentation tank are dewatered by a sludge dewatering device, and the dewatered sludge cake is periodically transported off-site for disposal.

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