A low sludge yield doubling combined multi-stage biochemical reaction sludge process reduction system and method thereof

Abstract

The application provides a low sludge yield multiplication combined multi-stage biochemical reaction sludge process reduction system, which is provided with an anaerobic hydrolysis reactor, an anaerobic sludge interception reactor, a first-stage anoxic reactor, a first-stage aerobic reactor, an oxygen-consuming reactor, at least one second-stage reactor and a second sedimentation tank which are sequentially communicated along the direction of sewage inflow, wherein the second-stage reactor comprises a second-stage anoxic reactor and a second-stage aerobic reactor which are sequentially communicated along the direction of sewage inflow, and the system further comprises a sludge tank. The application further provides a low sludge yield multiplication combined multi-stage biochemical reaction sludge process reduction method. The low sludge yield multiplication combined multi-stage biochemical reaction sludge process reduction system and method provided by the application greatly strengthen the carbon and nitrogen removal effect and improve the carbon and nitrogen removal efficiency, and the biological carbon and nitrogen removal efficiency is high, the system has strong impact resistance, sludge process reduction is realized, sludge and water are treated together, and the system is suitable for treating various scales of high-pollutant-content sewage.

Description

Technical Field

[0001] This invention belongs to the technical field of wastewater treatment and relates to a multi-stage biochemical reaction sludge reduction system and method with low sludge yield multiplication. Background Technology

[0002] Large quantities of high-concentration industrial wastewater typically have characteristics such as high COD, high TN, high ammonia nitrogen, and are difficult to degrade, making them a key focus and challenge for environmental protection in my country.

[0003] Biological wastewater treatment boasts advantages such as high treatment efficiency, low investment and operating costs, and convenient operation and management, making it a primary wastewater treatment process. Anaerobic biological wastewater treatment utilizes the biodegradation action of anaerobic or facultative anaerobic microorganisms under anaerobic conditions to convert various complex organic molecules in wastewater into smaller molecules such as acids, methane, or carbon dioxide, thereby degrading pollutants or improving the biodegradability of the wastewater. However, anaerobic biological treatment often struggles to reduce pollutants in wastewater to a sufficiently low level, necessitating combination with aerobic biological treatment methods to further remove pollutants such as COD and ammonia nitrogen. Therefore, the combined anaerobic and aerobic process is currently the mainstream wastewater treatment technology for treating high-concentration industrial wastewater.

[0004] Chinese invention patent (CN113443710A) describes "an integrated and efficient wastewater treatment method for nitrogen and carbon removal." This device inoculates a reactor with special sludge and achieves denitrification and carbon removal through a coupling of short-cut nitrification, anaerobic ammonia oxidation, and heterotrophic denitrification. However, the novel denitrification process employed in this method is difficult to debug, requires highly skilled operators for subsequent operation and maintenance, and is greatly affected by environmental factors, exhibiting poor shock resistance and unstable denitrification and carbon removal effects.

[0005] Chinese invention patent (CN2007100427929) describes a "shock-resistant, multiplier-type combined coking wastewater treatment process." This process enhances the denitrification and decarbonization of coking wastewater by sequentially setting up an anaerobic combined reactor, a sedimentation tank, an anoxic combined reactor, a decarbonization combined reactor, a nitrification combined reactor, a secondary sedimentation tank, spherical packing material, and microbial activators. However, this process suffers from several problems, including low denitrification efficiency in anoxic denitrification, high energy consumption in anoxic denitrification of high-ammonia-nitrogen wastewater, low total nitrogen removal rate in primary anoxic denitrification, low biofilm formation efficiency and easy detachment of suspended polyethylene spherical packing material in the decarbonization and nitrification combined reactions, unstable effect of microbial activators, and high sludge production. Summary of the Invention

[0006] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a low sludge yield multi-stage biochemical reaction sludge reduction system and method, which can resist shock loads, has high efficiency in biological carbon and nitrogen reduction, reduces sludge volume, and has low energy consumption; it is suitable for the treatment of high COD and high TN wastewater of various scales.

[0007] To achieve the above and other related objectives, the first aspect of the present invention provides a low sludge yield multi-stage biochemical reaction sludge reduction system, comprising an anaerobic hydrolysis reactor, an anaerobic sludge interception reactor, a primary anoxic reactor, a primary aerobic reactor, an oxygen deaerator, at least one secondary reactor, and a secondary sedimentation tank, arranged sequentially along the wastewater inlet direction. The secondary reactor includes a secondary anoxic reactor and a secondary aerobic reactor arranged sequentially along the wastewater inlet direction. The system also includes a sludge tank, which is connected to the anaerobic sludge interception reactor and the secondary sedimentation tank, respectively.

[0008] The second aspect of the present invention provides a method for reducing sludge in a multi-stage biochemical reaction process with a low sludge yield multiplication, comprising: subjecting wastewater to anaerobic hydrolysis, primary anoxic denitrification, aerobic decarbonization nitrification, oxygen desiccation, secondary anoxic denitrification, and aerobic decarbonization in sequence, and then separating aerobic sludge from effluent by gravity.

[0009] Preferably, the low sludge yield doubling compound multi-stage biochemical reaction sludge reduction method employs the aforementioned low sludge yield doubling compound multi-stage biochemical reaction sludge reduction system, comprising the following steps:

[0010] 1) Wastewater is fed into an anaerobic hydrolysis reactor for anaerobic hydrolysis. The wastewater is mixed by an anaerobic homogenizer. The concentration of anaerobic sludge in the wastewater is increased by anaerobic biological carriers on an anaerobic biological carrier distributor, thereby reducing the concentration of pollutants in the wastewater. The wastewater is then fed into an anaerobic sludge interception reactor to intercept the anaerobic sludge in the wastewater, resulting in the first effluent. Part of the anaerobic sludge is returned to the anaerobic hydrolysis reactor, and part is discharged to the sludge tank.

[0011] 2) The first effluent is fed into the first-stage anoxic reactor for first-stage anoxic denitrification reaction. The first effluent is mixed by the first-stage anoxic homogenizer. The anoxic biological carrier on the anoxic biological carrier distributor increases the concentration of anoxic sludge in the first-stage anoxic reactor and enhances the denitrification effect to obtain the second effluent.

[0012] 3) The second effluent is fed into the first-stage aerobic reactor for aerobic carbon reduction and nitrification. The suspended biological carriers in several aerobic reaction chambers carry out a stepwise biological distribution to reduce sludge production. The suspended biological carriers in the aerobic reaction chambers simultaneously increase the concentration of aerobic sludge in the first-stage aerobic reactor and enhance the aerobic carbon reduction and nitrification. Alkali source is added through the alkali source adder to supplement the alkalinity required for the growth of aerobic microorganisms, and the third effluent is obtained.

[0013] 4) The third effluent is fed into the deoxygenation reactor for deoxygenation reaction to remove dissolved oxygen from the third effluent. The third effluent is mixed by the deoxygenation homogenizer. After the deoxygenation reaction, part of the third effluent is returned to the first-stage anoxic reactor through the mixed liquid return device to achieve enhanced denitrification effect and obtain the fourth effluent.

[0014] 5) The fourth effluent is fed into the secondary anoxic reactor for secondary anoxic denitrification. The fourth effluent is mixed by the secondary anoxic homogenizer. Carbon source is added by the carbon source adder to reduce the total nitrogen concentration in the fourth effluent, thus obtaining the fifth effluent.

[0015] 6) The fifth effluent is fed into a secondary aerobic reactor for aerobic carbon reduction reaction to remove the residual carbon source in the fifth effluent, thus obtaining the sixth effluent;

[0016] 7) The sixth effluent is fed into the secondary sedimentation tank to separate the aerobic sludge from the effluent by gravity, and the effluent is obtained. Part of the aerobic sludge is returned to the primary anoxic reactor, and part is discharged to the sludge tank.

[0017] As described above, the present invention provides a low sludge yield multi-stage biochemical reaction sludge reduction system and method, which has the following beneficial effects:

[0018] (1) The present invention provides a low sludge production rate multi-stage biochemical reaction sludge process reduction system and method, which integrates the functions of anaerobic hydrolysis of sewage, anoxic denitrification, aerobic carbon reduction, aerobic nitrification, complete mixing, high sludge concentration, activated sludge coupled with biofilm, etc., which greatly enhances the carbon reduction and nitrogen removal effect of the system and improves the carbon reduction and nitrogen removal efficiency, and the biological carbon reduction and nitrogen removal efficiency is high.

[0019] (2) The present invention provides a low sludge production rate multi-stage biochemical reaction sludge process reduction system and method, which has strong shock resistance, realizes sludge process reduction and sludge-water co-treatment, has high shock load resistance, low sludge production, and low energy consumption, and is suitable for high COD and high TN wastewater treatment of various scales.

[0020] (3) The present invention provides a low sludge yield doubling compound multi-stage biochemical reaction sludge process reduction system and method, wherein the reactor adopts a completely mixed flow state and has strong shock resistance.

[0021] (4) The present invention provides a low sludge yield doubling composite multi-stage biochemical reaction sludge process reduction system and method, which adopts a two-stage anoxic denitrification and aerobic carbon reduction nitrification composite reactor, with a high total nitrogen removal rate.

[0022] (5) The present invention provides a low sludge production rate multi-stage biochemical reaction sludge process reduction system and method, which adopts two-stage anoxic denitrification, and can reduce the mixed liquor reflux ratio while ensuring the total nitrogen removal rate of the system, thereby improving the denitrification efficiency and saving energy consumption.

[0023] (6) The present invention provides a low sludge yield multi-stage biochemical reaction sludge process reduction system and method, which sets up an oxygen deoxygenation reactor after the first-stage aerobic reactor to reduce dissolved oxygen in the wastewater and reduce the inhibitory effect of dissolved oxygen in the return liquid on anoxic denitrifying bacteria, resulting in high anoxic denitrification efficiency.

[0024] (7) The present invention provides a low sludge yield multi-stage biochemical reaction sludge process reduction system and method, which constructs several aerobic reaction chambers in a primary aerobic reactor to form a floc section, a protozoan section and a metazoan section, and constructs a microbial food chain to reduce the sludge production of the system, thereby achieving sludge process reduction and sludge-water co-treatment.

[0025] (8) The present invention provides a low sludge yield multi-stage biochemical reaction sludge process reduction system and method, which constructs a "sludge-film" composite system of activated sludge and biofilm through the coupling effect of fixed stacked unfolded biological carrier and suspended biological carrier, partially realizing the separation of hydraulic retention time and sludge retention time, realizing "dual sludge age" microbial synergistic treatment, and simultaneously realizing synchronous nitrification and denitrification, with high carbon reduction and nitrogen removal efficiency.

[0026] (9) The present invention provides a low sludge production rate multi-stage biochemical reaction sludge process reduction system and method. The presence of biological carriers greatly increases the sludge concentration in the system, greatly increases the system volume load, reduces the system footprint, and greatly improves the system's resistance to water quality and quantity shocks. Attached Figure Description

[0027] Figure 1 The diagram shown is a structural flow chart of a multi-stage biochemical reaction sludge reduction system with a low sludge yield multiplication method according to the present invention.

[0028] Figure 2 The diagram shown is a process flow chart of a multi-stage biochemical reaction sludge reduction system with increased low sludge yield according to the present invention.

[0029] Figure 1 Chinese Attachment Labels

[0030] 1. Water inlet pipe

[0031] 2 Anaerobic hydrolysis reactor

[0032] 21 Anaerobic biological carrier distributor

[0033] 22 Anaerobic biological carriers

[0034] 23 Anaerobic homogenizer

[0035] 24 First Water Passage

[0036] 3 Anaerobic sludge interception reactor

[0037] 31 First reflux pipe

[0038] 32 First Reflux Pump

[0039] 33 First sludge discharge pipe

[0040] 34 First external discharge pump

[0041] 35 Second Water Passage

[0042] 4. Primary anoxic reactor

[0043] 41 Anaerobic biological carrier distributor

[0044] 42 Hypoxic biological carriers

[0045] 43. Primary hypoxic homogenizer

[0046] 44 Third Water Passage

[0047] 5. Primary aerobic reactor

[0048] 51 Aerobic Reaction Chamber

[0049] 52. Fourth Water-Passing Tunnel

[0050] 53 Suspended biological carriers

[0051] 54 First Aerator

[0052] 55 First Aeration Tube

[0053] 56 First Wire Mesh

[0054] 57 First dosing tube

[0055] 58. Fifth Water Passage

[0056] 59 Second Wire Mesh

[0057] 6. Deoxygenation reactor

[0058] 61 Mixture Reflux Device

[0059] 611 Mixture Reflux Pump

[0060] 62 Oxygen-free homogenizing mixer

[0061] 63 Return Channel

[0062] 64. The Sixth Water-Crossing Cave

[0063] 7. Secondary anoxic reactor

[0064] 71. Two-stage hypoxic homogenizer

[0065] 72 Second dosing tube

[0066] 73. The Seventh Water-Passing Cave

[0067] 8. Secondary aerobic reactor

[0068] 81 Second Aerator

[0069] 82 Second Aeration Tube

[0070] 83 The Eighth Water Passage

[0071] 84 Water pipe

[0072] 9 Secondary sedimentation tank

[0073] 91 Second reflux pipe

[0074] 92 Second reflux pump

[0075] 93 Second sludge discharge pipe

[0076] 94 Second External Drain Pump

[0077] 10 Sludge Tank

[0078] 11. Water outlet pipe

[0079] 12 Blowers

[0080] 13 Alkali source feeder

[0081] 14 Carbon source feeder Detailed Implementation

[0082] This invention provides a multi-stage biochemical reaction sludge reduction system with low sludge yield multiplication, such as... Figure 1 As shown, the system is provided with an anaerobic hydrolysis reactor, an anaerobic sludge interception reactor, a primary anoxic reactor, a primary aerobic reactor, an oxygen deaerator, at least one secondary reactor, and a secondary sedimentation tank connected in sequence along the wastewater inlet direction. The secondary reactor includes a secondary anoxic reactor and a secondary aerobic reactor connected in sequence along the wastewater inlet direction. The system also includes a sludge tank, which is connected to the anaerobic sludge interception reactor and the secondary sedimentation tank respectively.

[0083] In the above system, the anaerobic hydrolysis reactor is a conventionally used reactor. Specifically, the anaerobic hydrolysis reactor is a fully mixed reactor (continuous flow stirred tank reactor) used for anaerobic hydrolysis reaction. The anaerobic hydrolysis reactor is a reinforced concrete or carbon steel corrosion-resistant structure.

[0084] In the above system, such as Figure 1 As shown, the anaerobic hydrolysis reactor is externally connected to a water inlet pipe.

[0085] In the above system, such as Figure 1 As shown, the anaerobic hydrolysis reactor is equipped with an anaerobic biological carrier distributor. Specifically, the anaerobic biological carrier distributor is a support structure welded from one or more of angle steel, I-beam steel, channel steel, and round steel. Anaerobic biological carriers are distributed on the anaerobic biological carrier distributor. Specifically, the anaerobic biological carriers are selected from one or more of commercially available semi-soft packing materials, elastic three-dimensional packing materials, and combined packing materials.

[0086] In a preferred embodiment, the anaerobic biological carrier distributor is the stacked-plate unfolding biological carrier distribution device disclosed in the utility model patent "A stacked-plate unfolding suspended packing distribution device for sewage treatment" (ZL2017200516349) of Shanghai Zhongyao Environmental Protection Industry Co., Ltd., which serves as an anaerobic stacked-plate unfolding biological carrier distribution device in the anaerobic hydrolysis reactor.

[0087] In a preferred embodiment, the anaerobic biological carrier is the stacked unfolding biological carrier disclosed in the utility model patent "A stacked unfolding biological carrier for biological treatment of sewage and waste gas" (ZL2021212764083) of Shanghai Zhongyao Environmental Protection Industry Co., Ltd., which serves as an anaerobic stacked unfolding biological carrier in the anaerobic hydrolysis reactor.

[0088] In a preferred example, such as Figure 1 As shown, the anaerobic biological carrier distributor is located in the central region of the anaerobic hydrolysis reactor.

[0089] In the above system, such as Figure 1 As shown, the anaerobic hydrolysis reactor is equipped with at least one anaerobic homogenizer to ensure uniform mixing of the mud and water within the reactor.

[0090] In a preferred embodiment, the anaerobic homogenizer is a conventionally used homogenizer; specifically, it is a low-speed plug-flow homogenizer for anaerobic treatment. The anaerobic homogenizer is constructed of 304 stainless steel.

[0091] In a preferred example, such as Figure 1As shown, the anaerobic homogenizer is located at the bottom of the anaerobic hydrolysis reactor.

[0092] In the above system, such as Figure 1 As shown, the anaerobic hydrolysis reactor and the anaerobic sludge interception reactor are connected via a first water passage.

[0093] In the above system, such as Figure 1 As shown, the anaerobic sludge interception reactor is a sedimentation tank or an air flotation tank. It is used to separate anaerobic sludge and wastewater.

[0094] In the above system, such as Figure 1 As shown, the anaerobic sludge retention reactor is also connected to the anaerobic hydrolysis reactor via a first return pipe, and a first return pump is installed on the first return pipe. This pump is used to return the anaerobic sludge carried in the effluent to the anaerobic hydrolysis reactor to maintain the sludge concentration in the anaerobic hydrolysis reactor.

[0095] The aforementioned first reflux pump is a conventionally used pump; specifically, the first reflux pump is a screw pump.

[0096] In the above system, such as Figure 1 As shown, the anaerobic sludge interception reactor is also connected to the sludge tank via a first sludge discharge pipe, and a first external discharge pump is installed on the first sludge discharge pipe. This pump is used to discharge excess anaerobic sludge to the sludge tank.

[0097] The aforementioned first external discharge pump is a conventionally used pump; specifically, the first external discharge pump is a screw pump.

[0098] In the above system, such as Figure 1 As shown, the anaerobic sludge interception reactor is connected to the primary anoxic reactor via a second water passage.

[0099] In the above system, the primary anoxic reactor is a conventionally used reactor; specifically, it is a fully mixed reactor (continuous flow stirred tank reactor) used for anoxic reactions. The primary anoxic reactor is a reinforced concrete or carbon steel corrosion-resistant structure.

[0100] In the above system, such as Figure 1 As shown, the primary anoxic reactor is equipped with an anoxic biological carrier distributor. Specifically, the anoxic biological carrier distributor is a support structure welded from one or more of angle steel, I-beams, channel steel, and round steel. Anoxic biological carriers are distributed on the anoxic biological carrier distributor. Specifically, the anoxic biological carriers are selected from one or more of commercially available semi-flexible packing materials, elastic three-dimensional packing materials, and combined packing materials.

[0101] In a preferred embodiment, the anoxic biological carrier distributor is the stacked-plate unfolding biological carrier distribution device disclosed in the utility model patent "A Stacked-plate Unfolding Suspended Packing Material Distribution Device for Wastewater Treatment" (ZL2017200516349) of Shanghai Zhongyao Environmental Protection Industry Co., Ltd., which serves as an anoxic stacked-plate unfolding biological carrier distribution device in the primary anoxic reactor.

[0102] In a preferred embodiment, the anoxic biological carrier is the stacked unfolding biological carrier disclosed in the utility model patent "A stacked unfolding biological carrier for biological treatment of sewage and waste gas" (ZL2021212764083) of Shanghai Zhongyao Environmental Protection Industry Co., Ltd., which serves as an anoxic stacked unfolding biological carrier in a primary anoxic reactor.

[0103] In a preferred example, such as Figure 1 As shown, the anoxic biological carrier distributor is located in the central region of the primary anoxic reactor.

[0104] In the above system, such as Figure 1 As shown, the primary anoxic reactor is equipped with at least one primary anoxic homogenizer to ensure uniform mixing of the mud and water within the primary anoxic reactor.

[0105] In a preferred embodiment, the primary anoxic homogenizer is a conventionally used homogenizer; specifically, it is a low-speed plug-flow homogenizer for anoxic treatment. The primary anoxic homogenizer is constructed of 304 stainless steel.

[0106] In a preferred example, such as Figure 1 As shown, the primary anoxic homogenizer is located at the bottom of the primary anoxic reactor.

[0107] In the above system, such as Figure 1 As shown, the first-stage anoxic reactor and the first-stage aerobic reactor are connected via a third water passage.

[0108] In the above system, such as Figure 1 As shown, the primary aerobic reactor is a conventionally used reactor. Specifically, the primary aerobic reactor is a plug-flow reactor (continuous flow plug-flow tank reactor) used for aerobic decarbonization nitrification reaction. The primary aerobic reactor is a reinforced concrete or carbon steel corrosion-resistant structure.

[0109] In the above system, such as Figure 1 As shown, the primary aerobic reactor includes several aerobic reaction chambers, and adjacent aerobic reaction chambers are connected by a fourth water passage.

[0110] In a preferred example, such as Figure 1As shown, the number of aerobic reaction chambers is 3 to 5, preferably 3, and different reaction chambers are used to construct bacterial floc segments, protozoan segments, and metazoan segments to form a stepped biological distribution.

[0111] In a preferred example, such as Figure 1 As shown, the aerobic reaction chamber is equipped with a suspended biological carrier. This carrier is used to increase sludge concentration and enhance simultaneous nitrification and denitrification, thereby improving carbon reduction and nitrification efficiency.

[0112] In a further preferred embodiment, the suspended biological carrier is a commercially available high-specific-surface-area polymeric gel-like porous biological carrier. Specifically, the specific surface area of ​​the suspended biological carrier is ≥10000 m². 2 / m 3 The porosity is ≥98%. The suspended biological carrier is hydrophilic and oleophobic.

[0113] In a further preferred embodiment, the suspended biological carrier is filled to 15-30% of the aerobic reaction chamber.

[0114] In a preferred example, such as Figure 1 As shown, the aerobic reaction chamber is equipped with at least one first aerator, which is connected to a blower via a first aeration pipe. This aerator is used to supply oxygen to the aerobic reaction chamber of the primary aerobic reactor via the blower and to prevent the deposition of suspended biological carriers.

[0115] The first aerator mentioned above is a conventionally used aerator; specifically, it is a liftable tubular aerator. The blower mentioned above is a conventionally used blower; specifically, it is a centrifugal blower.

[0116] In a preferred example, such as Figure 1 As shown, a first wire mesh is installed in the fourth water passage along the water inlet direction. This mesh is used to intercept suspended biological carriers in the primary aerobic reactor, preventing them from flowing into subsequent processes.

[0117] The mesh size of the first wire mesh is 4-6 mm.

[0118] In the above system, such as Figure 1 As shown, the primary aerobic reactor is connected to an alkaline source feeder via a first feed pipe. This feeder is used to supplement the alkalinity of the primary aerobic reactor to create a suitable environment for microbial growth.

[0119] The aforementioned alkali source dosing device is a box-like structure used for dissolving, storing, and adding alkali sources. The alkali source dosing device can also be equipped with a stirring paddle for dissolving and mixing.

[0120] In a preferred example, such as Figure 1As shown, the alkali source feeder is connected via a first feed pipe to at least one of the following aerobic reaction chambers in the primary aerobic reactor:

[0121] A1) The alkali source dosing device is connected to the aerobic reaction chamber at the very end of the wastewater inlet direction in the first-stage aerobic reactor via the first dosing pipe;

[0122] A2) The alkali source dosing device is connected to the adjacent aerobic reaction chamber at the end of the aerobic reaction chamber along the sewage inlet direction in the first-stage aerobic reactor via the first dosing pipe.

[0123] In further preferred examples, such as Figure 1 As shown, the alkali source dosing device is connected to the aerobic reaction chamber at the very end of the primary aerobic reactor along the direction of wastewater inlet via the first dosing pipe.

[0124] In the above system, such as Figure 1 As shown, the primary aerobic reactor and the deoxygenated reactor are connected via the fifth water passage.

[0125] In a preferred example, such as Figure 1 As shown, a second wire mesh is provided inside the fifth water passage along the water inlet direction.

[0126] The mesh size of the second wire mesh is 4-6 mm.

[0127] In a preferred example, such as Figure 1 As shown, the deoxygenated reactor is connected to the aerobic reaction chamber at the very end of the primary aerobic reactor along the sewage inlet direction via the fifth water passage.

[0128] In the above system, the deoxygenation reactor is a conventionally used reactor; specifically, it is a fully mixed reactor (continuous flow stirred tank reactor) used for deoxygenation reactions. The deoxygenation reactor is a reinforced concrete or carbon steel corrosion-resistant structure.

[0129] In the above system, such as Figure 1 As shown, the deoxygenation reactor is equipped with at least one deoxygenation homogenizing mixer to ensure uniform mixing of the mud and water within the deoxygenation reactor.

[0130] In a preferred embodiment, the deoxygenated homogenizer is a conventionally used homogenizer; specifically, it is a mixing and stirring type homogenizer used for mixing and stirring processes. The deoxygenated homogenizer is constructed of 304 stainless steel.

[0131] In a preferred example, such as Figure 1 As shown, the deoxygenated homogenizer is located at the bottom of the deoxygenated reactor.

[0132] In the above system, such as Figure 1 As shown, the deoxygenated reactor is equipped with a mixed liquor reflux device, which is connected to the primary anoxic reactor via a reflux channel.

[0133] In a preferred example, such as Figure 1 As shown, the mixed liquor reflux device includes a mixed liquor reflux pump, which is connected to a reflux channel. It is used to reflux the mixed liquor from the deoxygenated reactor to the primary anoxic reactor.

[0134] In a preferred embodiment, the mixture reflux ratio in the mixture reflux device is ≤400%.

[0135] In the above system, such as Figure 1 As shown, the deoxygenated reactor and the secondary anoxic reactor are connected via the sixth water passage.

[0136] In the above system, such as Figure 1 As shown, the secondary anoxic reactor is a conventionally used reactor. Specifically, the secondary anoxic reactor is a fully mixed reactor (continuous flow stirred tank reactor) used for anoxic denitrification reaction. The secondary anoxic reactor is a reinforced concrete or carbon steel corrosion-resistant structure.

[0137] In the above system, such as Figure 1 As shown, the secondary anoxic reactor is equipped with at least one secondary anoxic homogenizer to ensure uniform mixing of the mud and water within the secondary anoxic reactor.

[0138] In a preferred embodiment, the secondary anoxic homogenizer is a conventionally used homogenizer; specifically, it is a mixing and stirring type homogenizer used for anoxic treatment. The secondary anoxic homogenizer is constructed of 304 stainless steel.

[0139] In a preferred example, such as Figure 1 As shown, the secondary anoxic homogenizer is located at the bottom of the secondary anoxic reactor.

[0140] In the above system, such as Figure 1 As shown, the secondary anoxic reactor is connected to a carbon source feeder via a second feed pipe. This feeder is used to supplement the carbon source required for denitrification in the secondary anoxic reactor.

[0141] The aforementioned carbon source dispenser is a box-like structure used for dissolving, storing, and adding carbon sources. The carbon source dispenser can also be equipped with a stirring paddle for dissolving and mixing.

[0142] In a preferred embodiment, the carbon source feeder is connected to the inlet of the secondary anoxic reactor via a second feed pipe.

[0143] In the above system, such as Figure 1 As shown, the secondary anoxic reactor and the secondary aerobic reactor are connected via the seventh water passage.

[0144] In the above system, such as Figure 1 As shown, the secondary aerobic reactor is a conventionally used reactor. Specifically, the secondary aerobic reactor is a plug-flow reactor (continuous flow plug-flow tank reactor) used for aerobic carbon reduction reactions. The secondary aerobic reactor is a reinforced concrete or carbon steel corrosion-resistant structure.

[0145] In the above system, such as Figure 1 As shown, the secondary aerobic reactor is equipped with a second aerator, which is connected to a blower via a second aeration pipe. This aerator is used to supply oxygen to the secondary aerobic reactor by blowing air through the blower.

[0146] In the above system, such as Figure 1 As shown, the secondary aerobic reactor is connected to the secondary sedimentation tank via the eighth water passage and a water conveyance pipe.

[0147] In the above system, such as Figure 1 As shown, the secondary sedimentation tank is a conventionally used reaction tank. The secondary sedimentation tank is a reinforced concrete or carbon steel corrosion-resistant structure.

[0148] In the above system, such as Figure 1 As shown, the secondary sedimentation tank is connected to the primary anoxic reactor via a second return pipe, and a second return pump is installed on the second return pipe. This pump is used to return the aerobic sludge carried in the effluent to the primary anoxic reactor to maintain the sludge concentration in the primary anoxic reactor.

[0149] The aforementioned second reflux pump is a conventionally used pump; specifically, the second reflux pump is a screw pump.

[0150] In the above system, such as Figure 1 As shown, the secondary sedimentation tank is also connected to the sludge tank via a second sludge discharge pipe, and a second external discharge pump is installed on the second sludge discharge pipe. This pump is used to discharge excess aerobic sludge into the sludge tank.

[0151] The aforementioned second external discharge pump is a conventionally used pump; specifically, the second external discharge pump is a screw pump.

[0152] In the above system, such as Figure 1 As shown, the secondary sedimentation tank is externally connected to an outlet pipe. This outlet pipe is used to direct the effluent from the secondary sedimentation tank into the subsequent treatment unit.

[0153] In the above system, such as Figure 1 As shown, the sludge tank is a conventionally used reaction tank. The sludge tank is a reinforced concrete or carbon steel corrosion-resistant structure.

[0154] In the above system, such as Figure 1 As shown, the third, fourth, fifth, sixth, seventh, and eighth water passages are respectively located at the top and bottom of the opposite sidewalls of the reactor, so that the distance between the water passages is kept as far as possible to avoid short-circuiting of sewage.

[0155] The second aspect of this invention provides a method for reducing sludge volume in a multi-stage biochemical reaction process with a low sludge yield multiplication factor, such as... Figure 2 As shown, the process includes: sequentially subjecting wastewater to anaerobic hydrolysis, primary anoxic denitrification, aerobic decarbonization nitrification, oxygen depletion, secondary anoxic denitrification, and aerobic decarbonization, followed by separation of aerobic sludge from effluent by gravity.

[0156] In the above method, the low sludge yield doubling composite multi-stage biochemical reaction sludge reduction method employs one of the aforementioned low sludge yield doubling composite multi-stage biochemical reaction sludge reduction systems, such as... Figure 2 As shown, it includes the following steps:

[0157] 1) Wastewater is fed into an anaerobic hydrolysis reactor for anaerobic hydrolysis. The wastewater is mixed by an anaerobic homogenizer. The concentration of anaerobic sludge in the wastewater is increased by anaerobic biological carriers on an anaerobic biological carrier distributor, thereby reducing the concentration of pollutants in the wastewater. The wastewater is then fed into an anaerobic sludge interception reactor to intercept the anaerobic sludge in the wastewater, resulting in the first effluent. Part of the anaerobic sludge is returned to the anaerobic hydrolysis reactor, and part is discharged to the sludge tank.

[0158] 2) The first effluent is fed into the first-stage anoxic reactor for first-stage anoxic denitrification reaction. The first effluent is mixed by the first-stage anoxic homogenizer. The anoxic biological carrier on the anoxic biological carrier distributor increases the concentration of anoxic sludge in the first-stage anoxic reactor and enhances the denitrification effect to obtain the second effluent.

[0159] 3) The second effluent is fed into the first-stage aerobic reactor for aerobic carbon reduction and nitrification. The suspended biological carriers in several aerobic reaction chambers carry out a stepwise biological distribution to reduce sludge production. The suspended biological carriers in the aerobic reaction chambers simultaneously increase the concentration of aerobic sludge in the first-stage aerobic reactor and enhance the aerobic carbon reduction and nitrification. Alkali source is added through the alkali source adder to supplement the alkalinity required for the growth of aerobic microorganisms, and the third effluent is obtained.

[0160] 4) The third effluent is fed into the deoxygenation reactor for deoxygenation reaction to remove dissolved oxygen from the third effluent. The third effluent is mixed by the deoxygenation homogenizer. After the deoxygenation reaction, part of the third effluent is returned to the first-stage anoxic reactor through the mixed liquid return device to achieve enhanced denitrification effect and obtain the fourth effluent.

[0161] 5) The fourth effluent is fed into the secondary anoxic reactor for secondary anoxic denitrification. The fourth effluent is mixed by the secondary anoxic homogenizer. Carbon source is added by the carbon source adder to reduce the total nitrogen concentration in the fourth effluent, thus obtaining the fifth effluent.

[0162] 6) The fifth effluent is fed into a secondary aerobic reactor for aerobic carbon reduction reaction to remove the residual carbon source in the fifth effluent, thus obtaining the sixth effluent;

[0163] 7) The sixth effluent is fed into the secondary sedimentation tank to separate the aerobic sludge from the effluent by gravity, and the effluent is obtained. Part of the aerobic sludge is returned to the primary anoxic reactor, and part is discharged to the sludge tank.

[0164] In step 1), the wastewater is fed into the anaerobic hydrolysis reactor through the inlet pipe.

[0165] In step 1), the mixing power of the anaerobic homogenizer is ≥8W / m³. 3 .

[0166] In step 1), in the anaerobic hydrolysis reactor, the vertical distance between the top of the anaerobic biological carrier and the water surface inside the anaerobic hydrolysis reactor is 0.5 to 0.8 m, and the vertical distance between the bottom of the anaerobic biological carrier and the bottom of the anaerobic hydrolysis reactor is 1.5 to 2 m.

[0167] In step 1), the hydraulic residence time of the anaerobic hydrolysis reaction is 8 to 12 hours.

[0168] In step 1), the concentration of suspended solids in the first effluent is ≤100mg / L.

[0169] In step 1), the anaerobic sludge is partially returned to the anaerobic hydrolysis reactor and kept running continuously, while the anaerobic sludge is partially discharged to the sludge tank for intermittent discharge.

[0170] In step 1), the reflux ratio of the anaerobic sludge partially returned to the anaerobic hydrolysis reactor is 5-20%.

[0171] In step 2), the dissolved oxygen (DO) concentration in the first-stage anoxic denitrification reaction is <0.5 mg / L.

[0172] In step 2), the mixing power of the primary anoxic homogenizer is ≥8W / m³. 3 .

[0173] In step 2), in the primary anoxic reactor, the vertical distance between the top of the anoxic biological carrier and the water surface in the primary anoxic reactor is 0.5 to 0.8 m, and the vertical distance between the bottom of the anoxic biological carrier and the bottom of the primary anoxic reactor is 1.5 to 2 m.

[0174] In step 3), the aerobic decarbonization nitrification reaction is carried out at a pH of 6.5 to 7.5 and a dissolved oxygen (DO) concentration of ≥2 mg / L.

[0175] In step 3), the suspended biological carrier flows uniformly along the sewage inlet direction in several aerobic reaction chambers, and is completely intercepted by the first and second wire meshes, with no accumulation in front of the first and second wire meshes.

[0176] In step 3), the condition for the suspended biological carrier is: specific surface area ≥ 10000 m². 2 / m 3 The porosity is ≥98%, and the fill rate is 15-30%.

[0177] In step 3), the alkali source is added by the alkali source adder when the pH is ≤ 6.5 at the end of the primary aerobic reactor. The alkali source adder operates intermittently.

[0178] In step 4), the dissolved oxygen (DO) concentration in the deoxygenation reactor is ≤1 mg / L.

[0179] In step 4), the mixing power of the oxygen-depleting homogenizing mixer is 3-8 W / m. 3 .

[0180] In step 4), the reflux ratio of the mixture in the reflux device is ≤400%. The mixture reflux device is kept running continuously.

[0181] In step 5), the dissolved oxygen (DO) concentration is ≤0.5 mg / L and the carbon-to-nitrogen ratio (C / N) is 4-5 in the secondary anoxic denitrification reaction.

[0182] In step 5), the mixing power of the secondary anoxic homogenizer is 3-8 W / m³. 3 .

[0183] In step 5), the carbon source dispenser adds carbon source when the carbon-to-nitrogen ratio (C / N) in the fourth effluent is ≤4, in order to maintain the carbon-to-nitrogen ratio (C / N) in the fourth effluent at 5-6. The carbon source dispenser operates intermittently.

[0184] In step 6), the dissolved oxygen (DO) concentration in the aerobic carbon reduction reaction is 1-2 mg / L.

[0185] In step 7), the concentration of suspended solids in the discharged water is ≤50mg / L.

[0186] In step 7), the aerobic sludge is partially returned to the primary anoxic reactor and kept running continuously, while the aerobic sludge is partially discharged to the sludge tank for intermittent discharge.

[0187] In step 7), the recirculation ratio of the aerobic sludge partially returned to the primary anoxic reactor is 50-100%.

[0188] In step 7), the discharged water is discharged through the outlet pipe.

[0189] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0190] Please see Figure 1 It should be understood that the structures, proportions, sizes, etc., illustrated in the accompanying drawings are merely for illustrative purposes to aid those skilled in the art and to facilitate understanding and reading. They are not intended to limit the scope of the invention and therefore have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, without affecting the effectiveness and purpose of the invention, should still fall within the scope of the technical content disclosed in this invention. Furthermore, the terms such as "upper," "lower," "left," "right," "middle," and "one" used in this specification are merely for clarity and not intended to limit the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention's implementation.

[0191] Example 1

[0192] Users obtain such Figure 1-2 The low sludge yield multi-stage biochemical reaction sludge reduction system shown is used to treat gasification wastewater. The gasification wastewater was tested and found to have a BOD5 of 500–600 mg / L, ammonia nitrogen of 150–180 mg / L, and total nitrogen of 180–210 mg / L.

[0193] The gasification wastewater is fed into the anaerobic hydrolysis reactor through the inlet pipe for anaerobic hydrolysis. The hydraulic retention time of the anaerobic hydrolysis reactor is 8 hours. An anaerobic homogenizer is used to thoroughly mix the sludge and water in the gasification wastewater, ensuring a completely mixed flow state within the reactor to improve its shock resistance. The mixing power of the anaerobic homogenizer is 10 W / m³. 3Simultaneously, within the anaerobic hydrolysis reactor, anaerobic biological carriers on an anaerobic biological carrier distributor are used to increase the concentration of anaerobic sludge. The top of the anaerobic biological carrier is 0.5m above the water surface, and the bottom is 2m below the bottom of the tank. This enhances the hydrolysis and acidification of the anaerobic sludge, improves the biodegradability of the gasification wastewater, and reduces pollutant concentration. The effluent from the anaerobic hydrolysis reactor is then fed into an anaerobic sludge interception reactor to intercept the anaerobic sludge carried in the gasification wastewater, maintaining the sludge concentration within the reactor. This yields the first effluent, with a suspended solids concentration of 80mg / L. Part of the anaerobic sludge is returned to the anaerobic hydrolysis reactor, and the excess is discharged to a sludge tank.

[0194] The first effluent is fed into a primary anoxic reactor for primary anoxic denitrification. The dissolved oxygen (DO) concentration in the primary anoxic reactor is 0.3 mg / L. A primary anoxic homogenizer ensures thorough mixing of the effluent and the resulting liquid, creating a completely mixed flow pattern within the reactor to enhance its resistance to shock loads. The primary anoxic homogenizer has a mixing power of 10 W / m³. 3 Simultaneously, within the primary anoxic reactor, the concentration of anoxic sludge is increased by using anoxic biological carriers distributed on anoxic biological carrier distributors. The top of the anoxic biological carrier is 0.5m above the water surface, and the bottom is 2m from the bottom of the tank. This allows denitrifying bacteria to attach and grow on the anoxic biological carrier, enhancing the anoxic denitrification process. Additionally, the carbon source in the gasified wastewater is used to reduce the total nitrogen concentration, resulting in the second effluent.

[0195] The second effluent is fed into a primary aerobic reactor for aerobic decarbonization and nitrification. The primary aerobic reactor has a pH of 7, a final DO concentration of 3 mg / L, and a packing surface area of ​​12,000 m². 2 / m 3The system employs a suspended biological carrier with a porosity of 98% and a filling rate of 20%. A stepped biological distribution within three aerobic reaction chambers reduces sludge production. The chamber is divided into three segments: a floc section, a protozoan section, and a metazoan section. The floc section feeds on pollutants in the second effluent, degrading them while simultaneously growing and reproducing microorganisms. Some microorganisms attach to the suspended biological carrier, while others flow into the subsequent protozoan section. The protozoan section feeds on flocs in the aquatic water, growing and reproducing, again attaching to the suspended biological carrier and flowing into the subsequent metazoan section. The metazoan section feeds on protozoa in the aquatic water, resulting in clean water and a small amount of metazoa. Since the amount of metazoa is far less than that of flocs, this stepped biological distribution significantly reduces sludge production. Meanwhile, the concentration of aerobic sludge in the second effluent is increased by the suspended biological carrier in the aerobic reaction chamber, and a sludge-film mixing environment is constructed to enable nitrifying bacteria with long sludge age to grow stably. The aerobic carbon reduction and nitrification effect is enhanced through synchronous nitrification and denitrification. Alkali source is added through an alkali source adder to supplement the alkalinity required for the growth of aerobic microorganisms. The alkali source is added at the end of the first-stage aerobic reactor when the pH is ≤6.5 to create a suitable growth environment for aerobic microorganisms and obtain the third effluent.

[0196] The third effluent is fed into a deaeration reactor for deaeration. The third effluent is then mixed using a deaeration homogenizing mixer with a mixing power of 6 W / m³. 3 The dissolved oxygen in the third effluent is reduced to 0.9 mg / L in the deoxygenated reactor. A portion of the third effluent is then returned to the first-stage anoxic reactor via a mixed liquor reflux device at a mixed liquor reflux ratio of 400%. This reduces the impact of dissolved oxygen in the third effluent on the anoxic denitrification process in the first-stage and second-stage anoxic reactors, thereby enhancing the nitrogen removal effect and obtaining the fourth effluent.

[0197] The fourth effluent is fed into a secondary anoxic reactor for secondary anoxic denitrification. The secondary anoxic reactor has a DO concentration of 0.5 mg / L and a C / N ratio of 4. The effluent is thoroughly mixed with the sludge in the secondary anoxic reactor using a secondary anoxic homogenizer with a mixing power of 5 W / m³. 3 Carbon source is added through a carbon source adder to reduce the total nitrogen concentration in the fourth effluent. The carbon source adder is added when the carbon-nitrogen ratio (C / N) in the fourth effluent is ≤4, in order to maintain the carbon-nitrogen ratio (C / N) in the fourth effluent at 5-6, thus obtaining the fifth effluent.

[0198] The fifth effluent is fed into a secondary aerobic reactor for aerobic carbon reduction reaction to remove residual carbon sources in the fifth effluent. The DO in the secondary aerobic reactor is 1.5 mg / L to ensure the COD of the effluent, thus obtaining the sixth effluent.

[0199] The sixth effluent is fed into the secondary sedimentation tank where gravity separates the aerobic sludge from the effluent. The effluent is then fed into the subsequent treatment unit through the effluent pipe. The suspended solids concentration in the effluent is 30 mg / L. Part of the aerobic sludge is returned to the primary anoxic reactor at a return ratio of 100%, and part is discharged to the sludge tank.

[0200] The effluent was tested and found to have COD less than 30 mg / L, ammonia nitrogen undetectable, and total nitrogen less than 20 mg / L. This system achieved excellent removal rates of COD, ammonia nitrogen, and total nitrogen in the gasification wastewater.

[0201] Example 2

[0202] Users obtain such Figure 1-2 The low sludge yield multi-stage biochemical reaction sludge reduction system shown is used to treat coking wastewater. The coking wastewater, after testing, showed a COD of [missing value]. cr The concentrations were 3500–4000 mg / L, ammonia nitrogen was 80–150 mg / L, and total nitrogen was 190–220 mg / L.

[0203] The gasification wastewater is fed into the anaerobic hydrolysis reactor through an inlet pipe for anaerobic hydrolysis. The hydraulic retention time in the anaerobic hydrolysis reactor is 12 hours. An anaerobic homogenizer is used to thoroughly mix the sludge and water in the gasification wastewater, ensuring a completely mixed flow state within the reactor to improve its shock resistance. The mixing power of the anaerobic homogenizer is 12 W / m³. 3 Simultaneously, within the anaerobic hydrolysis reactor, anaerobic biological carriers on an anaerobic biological carrier distributor are used to increase the concentration of anaerobic sludge. The top of the anaerobic biological carrier is 0.6m above the water surface, and the bottom is 1.9m from the bottom of the reactor. This enhances the hydrolysis and acidification of the anaerobic sludge, improves the biodegradability of the gasification wastewater, and reduces pollutant concentration. The effluent from the anaerobic hydrolysis reactor is then fed into an anaerobic sludge interception reactor to intercept the anaerobic sludge carried in the gasification wastewater, maintaining the sludge concentration within the reactor. This yields the first effluent, with a suspended solids concentration of 90mg / L. Part of the anaerobic sludge is returned to the anaerobic hydrolysis reactor, and the excess is discharged to a sludge tank.

[0204] The first effluent is fed into a primary anoxic reactor for primary anoxic denitrification. The dissolved oxygen (DO) concentration in the primary anoxic reactor is 0.4 mg / L. A primary anoxic homogenizer ensures thorough mixing of the effluent and the resulting liquid, creating a completely mixed flow pattern within the reactor to enhance its resistance to shock loads. The primary anoxic homogenizer has a mixing power of 9 W / m³. 3Simultaneously, within the primary anoxic reactor, the concentration of anoxic sludge is increased by using anoxic biological carriers distributed on an anoxic biological carrier distributor. The top of the anoxic biological carrier is 0.6m above the water surface, and the bottom is 1.9m from the bottom of the tank. This allows denitrifying bacteria to attach and grow on the anoxic biological carrier, enhancing the anoxic denitrification process. Furthermore, the carbon source in the gasified wastewater is used to reduce the total nitrogen concentration, resulting in the second effluent.

[0205] The second effluent is fed into a primary aerobic reactor for aerobic decarbonization and nitrification. The primary aerobic reactor has a pH of 7.5, a final DO concentration of 2.5 mg / L, and a packing surface area of ​​12,000 m². 2 / m 3 The system uses suspended biological carriers with a porosity of 99% and a filling rate of 30%. A stepped biological distribution within three aerobic reaction chambers reduces sludge production. The chambers are divided into flocculent, protozoan, and metazoan sections. The flocculent section feeds on pollutants in the second effluent, degrading them while simultaneously growing and reproducing microorganisms. Some microorganisms attach to the suspended biological carriers, while others flow into the subsequent protozoan section. The protozoan section feeds on flocculents in the aquatic water, growing and reproducing, again attaching to the suspended biological carriers and flowing into the subsequent metazoan section. The metazoan section feeds on protozoa in the aquatic water, resulting in clean water and a small amount of metazoa. Since the amount of metazoa is much smaller than that of flocculents, this stepped biological distribution significantly reduces sludge production. Meanwhile, the concentration of aerobic sludge in the second effluent is increased by the suspended biological carrier in the aerobic reaction chamber, and a sludge-film mixing environment is constructed to enable nitrifying bacteria with long sludge age to grow stably. The aerobic carbon reduction and nitrification effect is enhanced through synchronous nitrification and denitrification. Alkali source is added through an alkali source adder to supplement the alkalinity required for the growth of aerobic microorganisms. The alkali source is added at the end of the first-stage aerobic reactor when the pH is ≤6.5 to create a suitable growth environment for aerobic microorganisms and obtain the third effluent.

[0206] The third effluent is fed into the deaeration reactor for deaeration. The third effluent is then mixed using a deaeration homogenizing mixer with a mixing power of 5W / m³. 3 The dissolved oxygen in the third effluent is reduced to 1.0 mg / L in the deoxygenation reactor. A portion of the third effluent is then returned to the first-stage anoxic reactor via a mixed liquor reflux device with a mixed liquor reflux ratio of 400%. This reduces the impact of dissolved oxygen in the third effluent on the anoxic denitrification process in the first-stage and second-stage anoxic reactors, thereby enhancing the nitrogen removal effect and obtaining the fourth effluent.

[0207] The fourth effluent is fed into a secondary anoxic reactor for secondary anoxic denitrification. The secondary anoxic reactor has a DO concentration of 0.5 mg / L and a C / N ratio of 5. The effluent is thoroughly mixed with the sludge in the secondary anoxic reactor using a secondary anoxic homogenizer with a mixing power of 6 W / m³. 3 Carbon source is added through a carbon source adder to reduce the total nitrogen concentration in the fourth effluent. The carbon source adder is added when the carbon-nitrogen ratio (C / N) in the fourth effluent is ≤4, in order to maintain the carbon-nitrogen ratio (C / N) in the fourth effluent at 5-6, thus obtaining the fifth effluent.

[0208] The fifth effluent is fed into a secondary aerobic reactor for aerobic carbon reduction reaction to remove residual carbon sources in the fifth effluent. The DO in the secondary aerobic reactor is 2.0 mg / L to ensure the COD of the effluent, thus obtaining the sixth effluent.

[0209] The sixth effluent is fed into the secondary sedimentation tank where gravity separates the aerobic sludge from the effluent. The effluent is then fed into the subsequent treatment unit through the effluent pipe. The suspended solids concentration in the effluent is 20 mg / L. Part of the aerobic sludge is returned to the primary anoxic reactor at a return ratio of 100%, and part is discharged to the sludge tank.

[0210] The effluent was tested and found to have a COD of less than 200 mg / L, no ammonia nitrogen detected, and a total nitrogen of less than 20 mg / L. This system achieved excellent removal rates of COD, ammonia nitrogen, and total nitrogen in the coking wastewater, with an average removal rate of 94.74% for COD, 100% for ammonia nitrogen, and 90.48% for total nitrogen.

[0211] Example 3

[0212] The treatment process differs from Example 2 in that the third effluent directly enters the secondary sedimentation tank, without the installation of an oxygen deaerator, a secondary anoxic reactor, or a secondary aerobic reactor. A portion of the third effluent is recycled to the primary anoxic reactor. Testing of the discharged water showed a total nitrogen level of 50–70 mg / L, with an average total nitrogen removal rate of 68.18%, significantly lower than in Example 2.

[0213] Example 4

[0214] The treatment process differed from Example 2 in that the primary aerobic reactor did not include a suspended biological carrier. The effluent was tested and found to have a COD of 250–350 mg / L, ammonia nitrogen of 5–10 mg / L, and total nitrogen of 50–60 mg / L. The average removal rates for COD were 92.11%, ammonia nitrogen 93.33%, and total nitrogen 73.81%, respectively. Both the average removal rates for ammonia nitrogen and total nitrogen were significantly lower than those in Example 2.

[0215] In summary, the present invention provides a low-sludge-yield, multi-stage biochemical reaction sludge reduction system and method that integrates anaerobic hydrolysis, anoxic denitrification, aerobic carbon reduction, aerobic nitrification, complete mixing, high sludge concentration, and activated sludge coupled with biofilm, significantly enhancing the system's carbon and nitrogen reduction effects and improving its efficiency. Simultaneously, it exhibits strong shock resistance, achieves sludge reduction, and promotes sludge-water co-treatment, making it suitable for wastewater treatment of various scales with high pollutant content. Therefore, the present invention effectively overcomes the various shortcomings of existing technologies and possesses high industrial application value.

[0216] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A multi-stage biochemical reaction sludge reduction system with low sludge yield multiplication, characterized in that, The system is provided with an anaerobic hydrolysis reactor (2), an anaerobic sludge interception reactor (3), a primary anoxic reactor (4), a primary aerobic reactor (5), an oxygen deaerator reactor (6), at least one secondary reactor, and a secondary sedimentation tank (9) connected in sequence along the sewage inlet direction. The secondary reactor includes a secondary anoxic reactor (7) and a secondary aerobic reactor (8) connected in sequence along the sewage inlet direction. The system also includes a sludge tank (10), which is connected to the anaerobic sludge interception reactor (3) and the secondary sedimentation tank (9). The anaerobic sludge interception reactor (3) is also connected to the anaerobic hydrolysis reactor (2) via a first return pipe (31), and a first return pump (32) is provided on the first return pipe (31). The anaerobic sludge interception reactor (3) is also connected to the sludge tank (10) via the first sludge discharge pipe (33), and the first sludge discharge pipe (33) is equipped with a first external discharge pump (34). The primary aerobic reactor (5) includes several aerobic reaction chambers (51), and adjacent aerobic reaction chambers (51) are connected by a fourth water passage (52); The number of aerobic reaction chambers (51) is 3 to 5; forming a floc section, a protozoan section, and a metazoan section, forming a stepped biological distribution and reducing sludge production; The aerobic reaction chamber (51) is equipped with a suspended biological carrier (53); The aerobic reaction chamber (51) is equipped with at least one first aerator (54), which is connected to the blower (12) via a first aeration pipe (55). The fourth water passage (52) is provided with a first wire mesh (56) along the water inlet direction; The deoxygenated reactor (6) is equipped with a mixed liquor return device (61), which is connected to the primary anoxic reactor (4) via a return channel (63); The secondary sedimentation tank (9) is connected to the primary anoxic reactor (4) via a second reflux pipe (91), and a second reflux pump (92) is provided on the second reflux pipe (91). The anaerobic hydrolysis reactor (2) is equipped with an anaerobic biological carrier distributor (21), and anaerobic biological carriers (22) are distributed on the anaerobic biological carrier distributor (21). The first-stage anoxic reactor (4) is equipped with an anoxic biological carrier distributor (41), and anoxic biological carriers (42) are distributed on the anoxic biological carrier distributor (41). The primary aerobic reactor (5) is connected to the alkali source feeder (13) via the first feed pipe (57); The secondary anoxic reactor (7) is connected to the carbon source feeder (14) via the second feed pipe (72).

2. The low sludge yield multi-stage biochemical reaction sludge reduction system according to claim 1, characterized in that, Includes one or more of the following conditions: A1) The anaerobic hydrolysis reactor (2) is externally connected to a water inlet pipe (1); A2) The anaerobic hydrolysis reactor (2) is equipped with at least one anaerobic homogenizer (23); A3) The anaerobic hydrolysis reactor (2) and the anaerobic sludge interception reactor (3) are connected through the first water passage (24); A4) The anaerobic sludge interception reactor (3) and the primary anoxic reactor (4) are connected via a second water passage (35); A5) The primary anoxic reactor (4) is equipped with at least one primary anoxic homogenizer (43). A6) The first-stage anoxic reactor (4) and the first-stage aerobic reactor (5) are connected via the third water passage (44); A7) The primary aerobic reactor (5) and the deoxygenated reactor (6) are connected via the fifth water passage (58); A8) The deoxygenated reactor (6) is provided with at least one deoxygenated homogenizing mixer (62). A9) The mixture return device (61) includes a mixture return pump (611), which is connected to the return channel (63); The deoxygenated reactor (6) described in A10) is connected to the secondary anoxic reactor (7) via the sixth water passage (64); A11) The secondary anoxic reactor (7) is equipped with at least one secondary anoxic homogenizer (71). The secondary anoxic reactor (7) and the secondary aerobic reactor (8) described in A12) are connected via the seventh water passage (73); A13) The secondary aerobic reactor (8) is equipped with a second aerator (81), which is connected to the blower (12) via a second aeration pipe (82); The secondary aerobic reactor (8) described in A14) is connected to the secondary sedimentation tank (9) via the eighth water passage (83) and water supply pipe (84); A15) The secondary sedimentation tank (9) is also connected to the sludge tank (10) via the second sludge discharge pipe (93), and the second sludge discharge pipe (93) is equipped with a second external discharge pump (94). The secondary sedimentation tank (9) described in A16) is externally connected to an outlet pipe (11).

3. The low sludge yield multi-stage biochemical reaction sludge reduction system according to claim 2, characterized in that, In item A7), a second wire mesh (59) is provided inside the fifth water passage (58) along the water inlet direction.

4. A method for reducing sludge volume in a multi-stage biochemical reaction process with increased low sludge yield, characterized in that: The low sludge yield multi-stage biochemical reaction sludge reduction system according to any one of claims 1-3 includes: sequentially subjecting wastewater to anaerobic hydrolysis, primary anoxic denitrification, aerobic decarbonization nitrification, oxygen desiccation, secondary anoxic denitrification, and aerobic decarbonization, and then separating aerobic sludge from effluent by gravity.

5. The method for reducing sludge volume in a multi-stage biochemical reaction process with increased low sludge yield according to claim 4, characterized in that, Includes the following steps: 1) Wastewater is fed into an anaerobic hydrolysis reactor for anaerobic hydrolysis. The wastewater is mixed by an anaerobic homogenizer. The concentration of anaerobic sludge in the wastewater is increased by anaerobic biological carriers on an anaerobic biological carrier distributor, thereby reducing the concentration of pollutants in the wastewater. The wastewater is then fed into an anaerobic sludge interception reactor to intercept the anaerobic sludge in the wastewater, resulting in the first effluent. Part of the anaerobic sludge is returned to the anaerobic hydrolysis reactor, and part is discharged to the sludge tank. 2) The first effluent is fed into the first-stage anoxic reactor for first-stage anoxic denitrification. The first effluent is mixed by the first-stage anoxic homogenizer. The anoxic biological carrier on the anoxic biological carrier distributor increases the concentration of anoxic sludge in the first-stage anoxic reactor and enhances the denitrification process to obtain the second effluent. 3) The second effluent is fed into the first-stage aerobic reactor for aerobic carbon reduction and nitrification. The suspended biological carriers in several aerobic reaction chambers carry out a stepwise biological distribution to reduce sludge production. The suspended biological carriers in the aerobic reaction chambers simultaneously increase the concentration of aerobic sludge in the first-stage aerobic reactor and enhance the aerobic carbon reduction and nitrification. Alkali source is added through the alkali source adder to supplement the alkalinity required for the growth of aerobic microorganisms, and the third effluent is obtained. 4) The third effluent is fed into the deoxygenation reactor for deoxygenation reaction to remove dissolved oxygen from the third effluent. The third effluent is mixed by the deoxygenation homogenizer. After the deoxygenation reaction, part of the third effluent is returned to the first-stage anoxic reactor through the mixed liquor return device to achieve enhanced denitrification effect and obtain the fourth effluent. 5) The fourth effluent is fed into the secondary anoxic reactor for secondary anoxic denitrification. The fourth effluent is mixed by the secondary anoxic homogenizer. Carbon source is added by the carbon source adder to reduce the total nitrogen concentration in the fourth effluent, thus obtaining the fifth effluent. 6) The fifth effluent is fed into a secondary aerobic reactor for aerobic carbon reduction reaction to remove the residual carbon source in the fifth effluent, thus obtaining the sixth effluent; 7) The sixth effluent is fed into the secondary sedimentation tank, where gravity separates the aerobic sludge from the effluent, resulting in effluent. Part of the aerobic sludge is returned to the primary anoxic reactor, and part is discharged to the sludge tank.

6. The sludge reduction method for a multi-stage biochemical reaction process with increased low sludge yield according to claim 5, characterized in that, Step 1) includes one or more of the following conditions: C1) The mixing power of the anaerobic homogenizer is ≥8W / m 3 ; C2) The anaerobic biological carrier distributor is located in the central region of the anaerobic hydrolysis reactor; C3) The hydraulic retention time for the anaerobic hydrolysis reaction is 8-12 hours; C4) The concentration of suspended solids in the first effluent is ≤100mg / L; C5) The reflux ratio of the anaerobic sludge partially returned to the anaerobic hydrolysis reactor is 5-20%.

7. The sludge reduction method for a multi-stage biochemical reaction process with increased low sludge yield according to claim 6, characterized in that, In item C2), the vertical distance between the top of the anaerobic biological carrier and the water surface in the anaerobic hydrolysis reactor is 0.5~0.8m, and the vertical distance between the bottom of the anaerobic biological carrier and the bottom of the anaerobic hydrolysis reactor is 1.5~2m.

8. The sludge reduction method for a multi-stage biochemical reaction process with increased low sludge yield according to claim 5, characterized in that, Step 2) includes one or more of the following conditions: In the first-stage anoxic denitrification reaction described in D1), the dissolved oxygen concentration is <0.5 mg / L; D2) The mixing power of the primary anoxic homogenizer is ≥8W / m 3 ; D3) The hypoxic biological carrier distributor is located in the central region of the primary hypoxic reactor.

9. The method for reducing sludge volume in a multi-stage biochemical reaction process with increased low sludge yield according to claim 8, characterized in that, In item D3), the vertical distance between the top of the anoxic biological carrier and the water surface in the primary anoxic reactor is 0.5~0.8m, and the vertical distance between the bottom of the anoxic biological carrier and the bottom of the primary anoxic reactor is 1.5~2m.

10. The method for reducing sludge volume in a multi-stage biochemical reaction process with increased low sludge yield according to claim 5, characterized in that, Step 3) includes one or more of the following conditions: In the aerobic decarbonization nitrification reaction described in E1), the pH is 6.5~7.5 and the dissolved oxygen concentration is ≥2mg / L; E2) The condition for the suspended biological carrier is: specific surface area ≥ 10000 m² 2 / m 3 Porosity ≥ 98%, fill rate 15~30%; E3) The alkali source feeder is used to add alkali source at the end of the primary aerobic reactor when the pH is ≤6.

5.

11. The method for reducing sludge volume in a multi-stage biochemical reaction process with increased low sludge yield according to claim 5, characterized in that, Step 4) or 5) includes one or more of the following conditions: F1) In step 4), the dissolved oxygen concentration in the deoxygenation reactor is ≤1 mg / L; F2) In step 4), the mixing power of the oxygen-depleting homogenizer is 3~8W / m 3 ; F3) In step 4), the mixture reflux ratio of the mixture reflux device is ≤400%; F4) In step 5), the dissolved oxygen concentration in the secondary anoxic denitrification reaction is ≤0.5mg / L, and the carbon-to-nitrogen ratio is 4~5; F5) In step 5), the mixing power of the secondary anoxic homogenizer is 3~8W / m. 3 ; F6) In step 5), the carbon source is added by the carbon source adder when the carbon-nitrogen ratio in the fourth effluent is ≤4.

12. The method for reducing sludge volume in a multi-stage biochemical reaction process with increased low sludge yield according to claim 5, characterized in that, Step 6) or 7) includes one or more of the following conditions: G1) In step 6), the dissolved oxygen concentration in the aerobic carbon reduction reaction is 1~2 mg / L; G2) In step 7), the concentration of suspended solids in the discharged water is ≤50mg / L; G3) In step 7), the aerobic sludge is partially returned to the primary anoxic reactor at a return ratio of 50-100%.

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