High-efficiency and low-consumption high-concentration organic sewage treatment system and process for livestock breeding

Abstract

The invention discloses an efficient and low-consumption high-concentration organic sewage treatment system and process for livestock breeding. The high-concentration organic sewage treatment system for livestock breeding comprises a solid-liquid separation unit, a hydrolysis acidification tank, a first sedimentation tank, a methanogenesis reactor, a second sedimentation tank, a first-stage nitrification reactor, a third sedimentation tank, a first-stage denitrification reactor, a fourth sedimentation tank, a second-stage nitrification reactor and a fifth sedimentation tank which are arranged in sequence, the rear ends of the first sedimentation tank and the second-stage denitrification reactor are respectively connected with the methanogenesis reactor and the first-stage denitrification reactor. The system and the process provided by the invention can be operated with low power consumption without depending on high-power reflux of the nitrification liquid, can effectively save the alkali and carbon supplementing cost, and have the advantages of high reaction efficiency, strong anti-interference capability, simple sludge control, low working condition control difficulty and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of sewage treatment, and in particular to a high-efficiency and low-consumption livestock breeding high-concentration organic sewage treatment system and process. Background Art

[0002] Existing livestock and aquaculture wastewater is characterized by high COD, high ammonia nitrogen, high total phosphorus (TP), and high SS. Organic pollutant concentrations range from 8,000 to 50,000 mg / L COD, 600 to 2,000 mg / L ammonia nitrogen, 100 to 300 mg / L TP, and 5,000 to 30,000 mg / L SS (suspended solids), making it extremely difficult to treat.

[0003] COD removal must be achieved through a combined anaerobic and aerobic process. The efficiency of anaerobic treatment alone is too low, and the energy consumption of aerobic treatment alone is too high. Therefore, ammonia nitrogen removal must be achieved through a combined aerobic and anoxic process. In the traditional A / A / O process (anaerobic-anoxic-aerobic), sludge circulates throughout the system through nitrification solution return and sludge return, so the sludge from each reaction unit is mixed rather than strictly separated. This means that the sludge from the anaerobic, anoxic, and aerobic units will be mixed together, but the environmental conditions of each reaction unit are different, resulting in different growth advantages for different bacterial communities. For example, nitrifying bacteria in aerobic tanks are active under aerobic conditions, while denitrifying bacteria in anoxic tanks are active under anoxic conditions. However, the return of nitrification solution and sludge will cause the bacterial communities to mix. Therefore, in the traditional A / A / O process, each reaction unit uses mixed sludge rather than exclusive sludge. For example, the denitrifying bacteria in the anoxic tank account for 5-10%, and the nitrifying bacteria in the aerobic tank account for only about 10-30%. This results in a low reaction rate in each reaction unit, which is easily interfered with by other reactions. It is difficult to control the sludge age and sludge concentration, and the operating condition control is very difficult.

[0004] When treating high-ammonia nitrogen wastewater, the traditional A / A / O process requires a high recirculation ratio of nitrification liquid due to pre-denitrification to ensure a high removal rate. For example, when NH3-N is >1500mg / L, to achieve NH3-N <15mg / L, the nitrification liquid recirculation ratio must be 99 times. This high recirculation ratio significantly increases energy consumption, and the high recirculation ratio of nitrification liquid containing high dissolved oxygen in the anoxic tank makes denitrification difficult to proceed, and may even switch to aerobic conditions. Moreover, in the aerobic unit, nitrification and carbon reduction inhibit each other, making it difficult to ensure the efficient completion of the nitrification reaction. This is the core pain point that makes the A / A / O process for high-NH3-N wastewater difficult to operate in compliance with standards. Summary of the Invention

[0005] In order to overcome the shortcomings of the existing technology, the purpose of the present invention is to provide a high-efficiency and low-consumption livestock breeding high-concentration organic wastewater treatment system and process, which does not rely on high-fold reflux of nitrification liquid and can operate with low power consumption, and can effectively save the cost of alkali and carbon replenishment. It has the advantages of high reaction efficiency, strong anti-interference ability, simple sludge management and low difficulty in operating condition control.

[0006] The high-efficiency and low-consumption livestock breeding high-concentration organic wastewater treatment system of the present invention is implemented by the following technical solutions: A high-efficiency, low-consumption livestock breeding high-concentration organic wastewater treatment system comprises a solid-liquid separation unit, a hydrolysis acidification tank, a first sedimentation tank, a methanogenic reactor, a second sedimentation tank, a primary nitrification reactor, a third sedimentation tank, a primary denitrification reactor, a fourth sedimentation tank, a secondary nitrification reactor, a fifth sedimentation tank, a secondary denitrification reactor, and a sixth sedimentation tank, wherein the rear end of the first sedimentation tank is connected to the methanogenic reactor and the primary denitrification reactor respectively; The primary nitrification reactor and the secondary nitrification reactor are each equipped with a strong aeration system, and the primary nitrification reactor and the secondary nitrification reactor are each equipped with nitrification-specific sludge; the primary denitrification reactor and the secondary denitrification reactor are each equipped with a micro-aeration system, and the primary denitrification reactor and the secondary denitrification reactor are each equipped with denitrification-specific sludge; The first sedimentation tank is connected to the first sludge discharge facility, the first sludge discharge facility is connected to the first sludge return facility, the first sludge return facility is connected to the hydrolysis acidification tank, the second sedimentation tank is connected to the second sludge discharge facility, the second sludge discharge facility is connected to the second sludge return facility, the second sludge return facility is connected to the methanogenesis reactor, the third sedimentation tank is connected to the third sludge discharge facility, the third sludge discharge facility is connected to the third sludge return facility, the third sludge return facility is connected to the primary nitrification reactor, the fourth sedimentation tank is connected to the fourth sludge discharge facility, the fourth sludge discharge facility is connected to the fourth sludge return facility, the fourth sludge return facility is connected to the primary denitrification reactor, the fifth sedimentation tank is connected to the fifth sludge discharge facility, the fifth sludge discharge facility is connected to the fifth sludge return facility, the fifth sludge return facility is connected to the secondary nitrification reactor, the sixth sedimentation tank is connected to the sixth sludge discharge facility, the sixth sludge discharge facility is connected to the sixth sludge return facility, and the sixth sludge return facility is connected to the secondary denitrification reactor.

[0007] Furthermore, the nitrification-only sludge refers to sludge in which the nitrifying bacteria account for more than 90% of the microbial community; the denitrification-only sludge refers to sludge in which the denitrifying bacteria account for more than 90% of the microbial community.

[0008] Furthermore, the livestock breeding high-concentration organic wastewater treatment system also includes a sludge collection pool, and the first sludge discharge facility, the second sludge discharge facility, the third sludge discharge facility, the fourth sludge discharge facility, the fifth sludge discharge facility and the sixth sludge discharge facility are all connected to the sludge collection pool, and the sludge collection pool is connected to the sludge treatment system.

[0009] Furthermore, a water collecting tank is provided at the front end of the solid-liquid separation unit, and the water collecting tank is connected to the sludge collecting tank so that the supernatant of the sludge collecting tank can flow back to the water collecting tank.

[0010] Furthermore, the solid-liquid separation unit adopts multi-stage separation equipment, and each stage of separation equipment adopts a gravity separator, a centrifugal separator or an extrusion separator.

[0011] Furthermore, a regulating tank is provided between the solid-liquid separation unit and the hydrolysis acidification tank.

[0012] Furthermore, the strong aeration system adopts multiple layers of aeration devices, and each layer of aeration devices is independently equipped with an aeration fan; or, the strong aeration system is a pure oxygen supply system.

[0013] Furthermore, the rear end of the sixth sedimentation tank is sequentially provided with a coagulation and flocculation reactor, a final sedimentation tank, a deep treatment unit and a disinfection water tank.

[0014] The high-efficiency and low-consumption livestock breeding high-concentration organic wastewater treatment process of the present invention is implemented by the following technical solutions: A high-efficiency and low-consumption livestock breeding high-concentration organic wastewater treatment process is implemented using the above-mentioned livestock breeding high-concentration organic wastewater treatment system. The livestock breeding high-concentration organic wastewater treatment process includes the following steps: After the sewage is separated into solid and liquid by the solid-liquid separation unit, the effluent suspended solids concentration SS ≤ 5000 mg / L; The effluent from the solid-liquid separation unit enters the hydrolysis and acidification tank for hydrolysis and acidification reaction. The effluent from the hydrolysis and acidification tank enters the first sedimentation tank, and the effluent from the hydrolysis and acidification tank meets the COD / TKN=6~8; 10%~30% of the effluent from the first sedimentation tank enters the primary denitrification reactor, and the rest enters the methanogenic reactor. The effluent from the methanogenic reactor enters the second sedimentation tank, and the effluent from the methanogenic reactor meets the COD / TKN < 3; The effluent from the second sedimentation tank enters the primary nitrification reactor for nitrification reaction, and the effluent from the primary nitrification reactor enters the third sedimentation tank; The effluent from the third sedimentation tank enters the primary denitrification reactor. The mixed liquid formed by the effluent from the first sedimentation tank and the effluent from the third sedimentation tank satisfies the COD / TKN=3.5~5. The mixed liquid undergoes denitrification reaction in the primary denitrification reactor. The effluent from the primary denitrification reactor enters the fourth sedimentation tank. The effluent from the fourth sedimentation tank enters the secondary nitrification reactor for nitrification reaction, and the effluent from the secondary nitrification reactor enters the fifth sedimentation tank; The effluent from the fifth sedimentation tank enters the secondary denitrification reactor for denitrification reaction. When the carbon source is insufficient, the carbon source is supplemented to the secondary denitrification reactor through external supplementation. The effluent from the secondary denitrification reactor enters the sixth sedimentation tank.

[0015] Furthermore, the primary nitration reactor performs nitration reaction according to the following operating parameters: Reaction temperature 15-40°C, dissolved oxygen concentration 5-8 mg / L, sludge concentration 10,000-20,000 mg / L, sludge age 12-22 days, sludge load 0.5-1.0 kg NH3-N / (kg MLSS·d), pH ≥ 7.0; The primary denitrification reactor performs denitrification reaction according to the following operating parameters: Reaction temperature 15~35°C, dissolved oxygen concentration 0.2~0.6mg / L, sludge concentration 5000~15000mg / L, sludge age 8~18d, sludge load 0.1-0.5kgNO3 - / (kg MLSS·d), pH value = 6.5~8.0; The secondary nitration reactor performs nitration reaction according to the following operating parameters: Reaction temperature 15-40°C, dissolved oxygen concentration 4-8 mg / L, sludge concentration 5000-10000 mg / L, sludge age 15-25 days, sludge load 0.4-0.8 kg NH3-N / (kg MLSS·d), pH ≥ 7.0; The secondary denitrification reactor performs denitrification reaction according to the following operating parameters: Reaction temperature 15~35°C, dissolved oxygen concentration 0.2~0.6mg / L, sludge concentration 3000~6000mg / L, sludge age 18~28d, sludge load 0.05~0.15kgNO3 - / (kg MLSS·d), pH value = 6.5~8.0.

[0016] Compared with the prior art, the present invention has the following beneficial effects: The high-efficiency and low-consumption livestock breeding high-concentration organic wastewater treatment system and process provided by the present invention does not need to rely on high-multiple reflux of nitrification liquid and can operate with low power consumption. It can also effectively save the cost of alkali and carbon replenishment, and has the advantages of high reaction efficiency, strong anti-interference ability, simple sludge management and control, and low difficulty in operating condition control. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1This is a schematic diagram of a high-efficiency, low-consumption livestock breeding high-concentration organic wastewater treatment system and process according to an embodiment of the present invention. DETAILED DESCRIPTION

[0018] The present invention will be further described below in conjunction with the accompanying drawings and specific implementation methods. It should be noted that, under the premise of no conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0019] refer to Figure 1 The present invention provides a system and process for treating high-concentration organic wastewater from livestock farming with high efficiency and low energy consumption. The system and process of the present invention are mainly divided into three stages: a pretreatment stage, a nitrification-denitrification stage, and a final treatment stage.

[0020] The high-efficiency and low-consumption livestock breeding high-concentration organic wastewater treatment system of the embodiment of the present invention includes a solid-liquid separation unit, a hydrolysis acidification tank, a first sedimentation tank, a methanogenic reactor, a second sedimentation tank, a primary nitrification reactor, a third sedimentation tank, a primary denitrification reactor, a fourth sedimentation tank, a secondary nitrification reactor, a fifth sedimentation tank, a secondary denitrification reactor and a sixth sedimentation tank, wherein the rear ends of the first sedimentation tank are connected to the methanogenic reactor and the primary denitrification reactor, respectively.

[0021] Among them, the solid-liquid separation unit, the hydrolysis acidification tank, the first sedimentation tank, the methanogenic reactor and the second sedimentation tank are used to constitute the pretreatment stage of the present invention, which is used to perform solid-liquid separation + anaerobic and other pretreatment processes on the sewage. Specifically, the solid-liquid separation unit adopts multi-stage separation equipment, and each stage of separation equipment can adopt a gravity separator, a centrifugal separator or an extrusion separator. The lower the SS concentration of the effluent of the solid-liquid separation unit, the better. Therefore, a multi-stage separation method is adopted, and the effluent of the solid-liquid separation unit is ultimately required to meet SS≤5000mg / L. If SS is not effectively separated from sewage, except for anaerobic, the anoxic and aerobic processes at the back end cannot operate normally, so SS must be effectively removed in the pretreatment stage.

[0022] The anaerobic treatment of the present invention adopts a modified version of the UASB anaerobic reaction unit, which is divided into two stages, namely the hydrolysis and acidification tank and the methanogenetic reactor. The anaerobic process is the biochemical process with the lowest energy consumption for removing COD, so the anaerobic process should fully consider the removal of COD. However, the BOD in COD is a good self-sufficient carbon source for the denitrification reaction. Therefore, the anaerobic unit should provide a carbon source for the back-end denitrification process, which can greatly reduce the cost of purchasing a carbon source for denitrification. That is, on the one hand, the denitrification carbon source must be guaranteed, and on the other hand, COD must be fully degraded. For this reason, the anaerobic treatment can be divided into two stages, namely the hydrolysis and acidification tank and the methanogenetic reactor. The hydrolysis and acidification tank is used to carry out the hydrolysis and acidification reaction, and the methanogenetic reactor realizes the production of acetic acid and methane. The reaction efficiency of the hydrolysis and acidification tank is controlled at about 30%, ensuring that the effluent COD / TKN=6~8, and the reaction efficiency of the methanogenetic reactor reaches more than 80%, ensuring that the effluent COD / TKN<3.

[0023] The primary nitrification reactor, the third sedimentation tank, the primary denitrification reactor, the fourth sedimentation tank, the secondary nitrification reactor, the fifth sedimentation tank, the secondary denitrification reactor and the sixth sedimentation tank constitute the nitrification-denitrification stage of the present invention. The primary nitrification reactor and the secondary nitrification reactor are each equipped with a strong aeration system, and the primary nitrification reactor and the secondary nitrification reactor each cultivate nitrification-exclusive sludge. The primary denitrification reactor and the secondary denitrification reactor are each equipped with a micro-aeration system, and the primary denitrification reactor and the secondary denitrification reactor are each equipped with denitrification-exclusive sludge. Among them, the strong aeration system refers to an aeration system for providing a higher dissolved oxygen concentration, such as DO=4~8mg / L; the micro-aeration system refers to an aeration system for providing a lower dissolved oxygen concentration, such as DO=0.2~0.6mg / L. Specifically, the strong aeration system adopts a multi-layer aeration device, and each layer of aeration device is independently equipped with an aeration fan; or, the strong aeration system is a pure oxygen supply system. The micro-aeration system is a micro-oxygen supply system. The purpose of setting up the micro-aeration system is to prevent the denitrification reactor from becoming an anaerobic working condition. The low concentration of dissolved oxygen helps to maintain the anoxic working condition.

[0024] The first sedimentation tank is connected to the first sludge discharge facility, the first sludge discharge facility is connected to the first sludge return facility, the first sludge return facility is connected to the hydrolysis acidification tank, the second sedimentation tank is connected to the second sludge discharge facility, the second sludge discharge facility is connected to the second sludge return facility, the second sludge return facility is connected to the methanogenesis reactor, the third sedimentation tank is connected to the third sludge discharge facility, the third sludge discharge facility is connected to the third sludge return facility, the third sludge return facility is connected to the primary nitrification reactor, the fourth sedimentation tank is connected to the fourth sludge discharge facility, the fourth sludge discharge facility is connected to the fourth sludge return facility, the fourth sludge return facility is connected to the primary denitrification reactor, the fifth sedimentation tank is connected to the fifth sludge discharge facility, the fifth sludge discharge facility is connected to the fifth sludge return facility, the fifth sludge return facility is connected to the secondary nitrification reactor, the sixth sedimentation tank is connected to the sixth sludge discharge facility, the sixth sludge discharge facility is connected to the sixth sludge return facility, and the sixth sludge return facility is connected to the secondary denitrification reactor.

[0025] The back end of each bioreactor unit in the present invention is equipped with a sedimentation tank, sludge discharge facilities, and sludge return facilities to achieve sludge interception, discharge, and return. Therefore, each bioreactor unit uses dedicated sludge. For example, the nitrification reactor uses nitrification-specific sludge, which refers to sludge in which nitrifying bacteria account for more than 90% of the microbial community; the denitrification reactor uses denitrification-specific sludge, which refers to sludge in which denitrifying bacteria account for more than 90% of the microbial community.

[0026] The livestock breeding high-concentration organic wastewater treatment system of the embodiment of the present invention also includes a sludge collection tank, and the first sludge discharge facility, the second sludge discharge facility, the third sludge discharge facility, the fourth sludge discharge facility, the fifth sludge discharge facility and the sixth sludge discharge facility are all connected to the sludge collection tank, and the sludge collection tank is connected to the sludge treatment system.

[0027] In the livestock breeding high-concentration organic wastewater treatment system of the present invention, a water collection tank is provided at the front end of the solid-liquid separation unit. The water collection tank is connected to the sludge collection tank to allow the supernatant from the sludge collection tank to flow back to the water collection tank. Because the supernatant from the sludge collection tank does not meet the discharge standards, it needs to be returned to the water collection tank. In addition, a regulating tank is provided between the solid-liquid separation unit and the hydrolysis and acidification tank to serve as a buffer.

[0028] In the livestock breeding high-concentration organic wastewater treatment system of this embodiment of the present invention, the rear end of the sixth sedimentation tank is sequentially provided with a coagulation and flocculation reactor, a final settling tank, an advanced treatment unit, and a disinfection and clear water tank. The coagulation and flocculation reactor, the final settling tank, the advanced treatment unit, and the disinfection and clear water tank constitute the final treatment stage of the present invention.

[0029] The highly efficient and low-consumption livestock farming high-concentration organic wastewater treatment process of the present invention is implemented using the above-mentioned livestock farming high-concentration organic wastewater treatment system. The livestock farming high-concentration organic wastewater treatment process includes a pretreatment step S100, a nitrification-denitrification step S200, and a final treatment step S300.

[0030] The preprocessing step S100 includes the following sub-steps S101~S102. S101. After the sewage is separated into solid and liquid by the solid-liquid separation unit, the effluent suspended solids concentration SS is ≤ 5000 mg / L.

[0031] S102. The effluent from the solid-liquid separation unit enters the hydrolysis and acidification tank for hydrolysis and acidification reaction. The effluent from the hydrolysis and acidification tank enters the first sedimentation tank, and the effluent from the hydrolysis and acidification tank meets COD / TKN=6~8.

[0032] S103: 10%-30% of the effluent from the first sedimentation tank enters the primary denitrification reactor, while the remaining effluent enters the methanogenic reactor. The effluent from the methanogenic reactor enters the second sedimentation tank, and the effluent from the methanogenic reactor meets the COD / TKN ratio of <3. Of these, 10%-30% of the effluent from the first sedimentation tank enters the primary denitrification reactor. The specific purpose is to use a portion of the effluent from the hydrolysis and acidification tank to provide an internal carbon source for the primary denitrification reactor. This significantly reduces the cost of purchasing external carbon sources for denitrification, ensuring a carbon source for denitrification while achieving sufficient COD degradation.

[0033] The nitrification-denitrification step S200 includes the following steps S201 to S204.

[0034] S201. The effluent from the second sedimentation tank enters the primary nitrification reactor for nitrification, and the effluent from the primary nitrification reactor enters the third sedimentation tank. The primary nitrification reactor performs the nitrification reaction according to the following operating parameters: reaction temperature 15-40°C, dissolved oxygen concentration 5-8 mg / L, sludge concentration 10,000-20,000 mg / L, sludge age 12-22 days, sludge loading 0.5-1.0 kg NH₃-N / (kg MLSS·d), and pH ≥ 7.0.

[0035] In step S201, the COD / TKN ratio of the wastewater entering the primary nitrification reactor is less than 3. Experimental results show that when the COD / TKN ratio is less than 3.5 and the dissolved oxygen (DO) in the reactor is greater than 3.5 mg / L, nitrification becomes the dominant reaction, while carbon reduction (COD decomposition) becomes the weaker reaction. When the dissolved oxygen (DO) exceeds 5 mg / L, carbon reduction is significantly inhibited. Setting the dissolved oxygen (DO) in the primary nitrification reactor between 5 and 8 mg / L ensures full nitrification and keeps COD decomposition efficiency below 3%.

[0036] Because 7.14 parts of alkalinity are lost for each completed nitrification reaction, the alkalinity of the nitrification reactor rapidly decreases, and the pH also drops accordingly. To minimize alkalinity loss and the impact on the pH balance within the primary nitrification reactor, the primary nitrification influent is taken from the effluent of the second anaerobic stage (i.e., the effluent of the methanogenic reactor). When the anaerobic acetic acid methanogenic reaction is completed, the alkalinity of the wastewater increases by 0.83g (in CaCO₃) for every 1g of acetic acid that completes the methanogenic reaction. Although alkalinity is lost during the hydrolysis and acidification reaction, the combined alkalinity of the wastewater and that generated during the methanogenic stage results in a net increase in alkalinity. Theoretically, in an anaerobic reaction system with a COD > 15,000 mg / L, the anaerobic completion of the methanogenic stage can compensate for 30-40% of the alkalinity lost during nitrification of 1,000 mg / L NH₃-N. This is a key reason for the primary nitrification influent of the present invention to be taken from the effluent of the anaerobic methanogenic stage.

[0037] In addition, when the alkalinity of the nitrification reactor is insufficient, the microorganisms will adjust the pH value through endogenous respiration. In the nitrification reaction of the traditional A / O process, the heterotrophic bacteria will compete for the oxygen source when the carbon source is sufficient, resulting in the microorganisms not getting enough oxygen to complete endogenous respiration to achieve pH adjustment. Therefore, the aerobic tank of the traditional A / O process cannot use endogenous respiration to achieve alkali supplementation. However, the nitrification process of the present invention is carried out in an environment of C / TKN<3 and uses exclusive sludge. Therefore, the microorganisms can adjust the pH value of the environment through endogenous respiration, thus solving the problem of needing external alkali supplementation.

[0038] S202, the effluent from the third sedimentation tank enters the primary denitrification reactor. The mixed solution formed by the effluent from the first sedimentation tank and the effluent from the third sedimentation tank satisfies COD / TKN=3.5-5. The mixed solution undergoes denitrification reaction in the primary denitrification reactor, and the effluent from the primary denitrification reactor enters the fourth sedimentation tank. The primary denitrification reactor performs denitrification reaction according to the following operating parameters: reaction temperature 15-35°C, dissolved oxygen concentration 0.2-0.6 mg / L, sludge concentration 5000-15000 mg / L, sludge age 8-18 days, and sludge load 0.1-0.5 kg NO3 - / (kg MLSS·d), pH value = 6.5~8.0.

[0039] In step 202, part of the carbon source for denitrification comes from the effluent of the first anaerobic stage (i.e., the effluent of the hydrolysis and acidification tank). Usually, the nitrification liquid also contains carbon sources with a COD / TKN ratio of about 2. The COD / TKN ratio of the mixed solution of the effluent of the first anaerobic stage and the nitrification liquid must be between 3.5 and 5. This determines the ratio of the nitrification liquid to the effluent of the first anaerobic stage entering the primary denitrification reactor.

[0040] In addition, because the third sedimentation tank will consume a large amount of dissolved oxygen in the nitrification liquid, in order to prevent the first-stage denitrification reactor from becoming anaerobic, the first-stage denitrification reactor is equipped with a micro-aeration system to maintain the dissolved oxygen concentration at 0.2~0.6mg / L.

[0041] Since 10% to 30% of the anaerobic effluent does not undergo nitrification, it is difficult to ensure efficient removal of ammonia nitrogen with the first-level 0A process. Therefore, a second-level 0A process is also set up, namely the secondary nitrification reactor and the secondary denitrification reactor.

[0042] S203. The effluent from the fourth sedimentation tank enters the secondary nitrification reactor for nitrification, and the effluent from the secondary nitrification reactor enters the fifth sedimentation tank. The secondary nitrification reactor performs nitrification according to the following operating parameters: reaction temperature 15-40°C, dissolved oxygen concentration 4-8 mg / L, sludge concentration 5000-10000 mg / L, sludge age 15-25 days, sludge loading 0.4-0.8 kgNH3-N / (kg MLSS·d), and pH ≥7.0.

[0043] Because a large amount of carbon source is consumed by the denitrification reaction in the primary denitrification reactor, the COD / TKN ratio of the primary denitrification effluent is less than 3. Therefore, effective nitrification can be ensured by controlling the dissolved oxygen (DO) in the secondary nitrification reactor between 4 and 6 mg / L. Furthermore, the alkalinity issue in the secondary nitrification reaction is essentially resolved due to the significant increase in alkalinity caused by the primary denitrification reaction, eliminating the need for endogenous microbial respiration regulation. Consequently, the dissolved oxygen can be reduced by 20-30% compared to the primary nitrification reaction.

[0044] S204. The effluent from the fifth sedimentation tank enters the secondary denitrification reactor for denitrification. When the carbon source is insufficient, the secondary denitrification reactor is supplemented with carbon source through external supplementation. The effluent from the secondary denitrification reactor enters the sixth sedimentation tank. The secondary denitrification reactor performs denitrification according to the following operating parameters: reaction temperature 15-35°C, dissolved oxygen concentration 0.2-0.6 mg / L, sludge concentration 3000-6000 mg / L, sludge age 18-28 days, and sludge load 0.05-0.15 kg NO3 - / (kgMLSS·d), pH value = 6.5~8.0.

[0045] In step S204, the secondary denitrification reactor's influent comes from the effluent from the sedimentation tank after secondary nitrification. Therefore, the secondary denitrification reactor also requires a micro-aeration system. The carbon source for the secondary denitrification reactor must be supplemented externally, at a rate of approximately 50% of the required carbon source. The sludge age of the secondary denitrification reactor should be between 18 and 28 days to allow the denitrifying bacteria to utilize the refractory organic matter as a carbon source.

[0046] The characteristics of the nitrification and denitrification process of the present invention are that nitrification comes first and denitrification comes later. This combination solves the problem of high-multiple nitrification liquid backflow when denitrification comes first, can greatly save energy consumption, and achieve low-power operation. The sedimentation tank at the rear end of the nitrification reactor can play the role of sludge interception and dissolved oxygen consumption, so as to avoid the impact of high concentration of dissolved oxygen on the anoxic working condition of the denitrification reactor. The specific principle is that the sedimentation tank realizes solid-liquid separation by gravity sedimentation to intercept suspended sludge, and the microorganisms in the sludge layer at the bottom of the sedimentation tank will consume a large amount of dissolved oxygen through endogenous respiration.

[0047] In addition, in order to achieve a one-way flow of wastewater between nitrification and denitrification, the nitrification and denitrification reactors are required to have a very high level of reaction efficiency and anti-interference ability. Therefore, a sedimentation tank is set at the rear end of the methanogenic reactor, the rear end of the primary and secondary nitrification reactors, and the rear end of the primary and secondary denitrification reactors, and sludge discharge facilities, sludge return facilities, etc. are configured. This makes it very convenient to control the sludge concentration and sludge age, and effectively avoid sludge mixing. Therefore, exclusive sludge can be used. For example, the nitrification reactor uses exclusive nitrification sludge, so that the microorganisms in the nitrification reactor are almost all nitrifying bacteria. The denitrification reactor uses exclusive denitrification sludge, so that the microorganisms in the denitrification reactor are almost all denitrifying bacteria. The cultivation and use of exclusive sludge for nitrification and denitrification greatly increases the reaction efficiency and also greatly reduces the interference of other reactions.

[0048] The final treatment step S300 includes: the effluent from the sixth sedimentation tank enters the coagulation and flocculation reactor, the effluent from the coagulation and flocculation reactor enters the final sedimentation tank, the effluent from the final sedimentation tank enters the deep treatment unit, and the effluent from the deep treatment unit enters the disinfection water tank.

[0049] Specifically, the advanced treatment unit performs the following functions: ① Removal of refractory COD; ② Chemical phosphorus removal; ③ Removal of pathogenic microorganisms; and ④ Removal of turbidity and soil sludge (SS). The two-stage nitrification and denitrification process can remove over 99% of NH3-N and TN. Anaerobic treatment combined with nitrification and denitrification can remove over 95% of COD from wastewater. Only residual carbon sources, which are non-biodegradable and replenished by the second-stage denitrification process, may remain in the wastewater. After coagulation, flocculation, advanced treatment, and disinfection, aquaculture wastewater can be treated to standards exceeding the "Urban Domestic Wastewater Discharge Standards" for safe discharge.

[0050] The high-efficiency, low-consumption livestock breeding high-concentration organic wastewater treatment system and process of the present invention have the following advantages over the prior art: 1) Nitrification and denitrification reactors utilize proprietary sludge, allowing for a significant increase in sludge concentration without the risk of sludge bulking, effectively reducing the risk of sludge bulking. This, coupled with a significant increase in the proportion of proprietary bacterial communities, significantly increases reaction efficiency (by more than 10 times). Furthermore, each reaction unit is free from interference from other reactions, ensuring a smoother reaction.

[0051] 2) Over 50% to 60% of the COD in wastewater can be fully decomposed through anaerobic decomposition. Approximately 10% to 20% of the COD is used as a carbon source for denitrification. Physicochemical processes such as solid-liquid separation and sedimentation can also remove over 30% of the COD. This eliminates the need for aerobic processes to decompose the COD, significantly reducing the energy consumption of aerobic reactions. Furthermore, the full anaerobic reaction allows for the recovery of more biogas energy. Anaerobic decomposition of COD also reduces sludge production by over two-thirds compared to aerobic decomposition. Conventional A / O processes require a C / N ratio of 5 to 7 for wastewater entering the process, meaning that 40% to 60% of the oxygen is used for COD decomposition. Therefore, the patented process can save oxygen supply energy by 40% to 60% and reduce sludge production by over 50%.

[0052] 3) Since alkali replenishment is achieved within the system, the cost of alkali replenishment can be effectively saved; in addition, only a small amount of carbon source needs to be added in the secondary denitrification, so the actual cost of carbon replenishment is very low, effectively solving the problem of carbon replenishment cost.

[0053] 4) There is no need to rely on high-fold reflux of nitrating solution, thus effectively saving energy consumption caused by reflux of nitrating solution.

[0054] 5) Since each reaction unit has an independent sedimentation tank, it is easier to control the sludge concentration and sludge age, and can better remove phosphorus.

[0055] 6) The reaction process is more stable, the operation is less difficult, and the working condition control is less difficult, which is more conducive to the realization of automated operation and management.

[0056] In summary, the livestock breeding high-concentration organic wastewater treatment system and process provided by the present invention do not need to rely on high-fold reflux of nitrification liquid and can operate with low power consumption, and can effectively save the cost of alkali and carbon replenishment. It has the advantages of high reaction efficiency, strong anti-interference ability, simple sludge management and low difficulty in working condition control, and ultimately achieves the goal of high efficiency and low consumption.

[0057] The above embodiments are only preferred embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantial changes and replacements made by technicians in this field on the basis of the present invention fall within the scope of protection required by the present invention.

Claims

1. A high-efficiency and low-consumption livestock breeding high-concentration organic wastewater treatment system, characterized in that: The system comprises a solid-liquid separation unit, a hydrolysis acidification tank, a first sedimentation tank, a methanogenic reactor, a second sedimentation tank, a primary nitrification reactor, a third sedimentation tank, a primary denitrification reactor, a fourth sedimentation tank, a secondary nitrification reactor, a fifth sedimentation tank, a secondary denitrification reactor and a sixth sedimentation tank, the rear end of the first sedimentation tank being connected to the methanogenic reactor and the primary denitrification reactor respectively; The primary nitrification reactor and the secondary nitrification reactor are each equipped with a strong aeration system, and the primary nitrification reactor and the secondary nitrification reactor are each equipped with nitrification-specific sludge; the primary denitrification reactor and the secondary denitrification reactor are each equipped with a micro-aeration system, and the primary denitrification reactor and the secondary denitrification reactor are each equipped with denitrification-specific sludge; The first sedimentation tank is connected to the first sludge discharge facility, the first sludge discharge facility is connected to the first sludge return facility, the first sludge return facility is connected to the hydrolysis acidification tank, the second sedimentation tank is connected to the second sludge discharge facility, the second sludge discharge facility is connected to the second sludge return facility, the second sludge return facility is connected to the methanogenesis reactor, the third sedimentation tank is connected to the third sludge discharge facility, the third sludge discharge facility is connected to the third sludge return facility, the third sludge return facility is connected to the primary nitrification reactor, the fourth sedimentation tank is connected to the fourth sludge discharge facility, the fourth sludge discharge facility is connected to the fourth sludge return facility, the fourth sludge return facility is connected to the primary denitrification reactor, the fifth sedimentation tank is connected to the fifth sludge discharge facility, the fifth sludge discharge facility is connected to the fifth sludge return facility, the fifth sludge return facility is connected to the secondary nitrification reactor, the sixth sedimentation tank is connected to the sixth sludge discharge facility, the sixth sludge discharge facility is connected to the sixth sludge return facility, and the sixth sludge return facility is connected to the secondary denitrification reactor.

2. The livestock breeding high-concentration organic wastewater treatment system according to claim 1, characterized in that: The nitrification-only sludge refers to sludge in which the nitrifying bacteria account for more than 90% of the microbial community; the denitrification-only sludge refers to sludge in which the denitrifying bacteria account for more than 90% of the microbial community.

3. The livestock breeding high-concentration organic wastewater treatment system according to claim 1, characterized in that: The livestock breeding high-concentration organic wastewater treatment system also includes a sludge collection pool, and the first sludge discharge facility, the second sludge discharge facility, the third sludge discharge facility, the fourth sludge discharge facility, the fifth sludge discharge facility and the sixth sludge discharge facility are all connected to the sludge collection pool, and the sludge collection pool is connected to the sludge treatment system.

4. The livestock breeding high-concentration organic wastewater treatment system according to claim 1, characterized in that: A water collecting tank is provided at the front end of the solid-liquid separation unit, and the water collecting tank is connected to the sludge collecting tank so that the supernatant in the sludge collecting tank can flow back to the water collecting tank.

5. The livestock breeding high-concentration organic wastewater treatment system according to claim 1, characterized in that: The solid-liquid separation unit adopts multi-stage separation equipment, and each stage of separation equipment adopts a gravity separator, a centrifugal separator or an extrusion separator.

6. The livestock breeding high-concentration organic wastewater treatment system according to claim 1, characterized in that: A regulating tank is provided between the solid-liquid separation unit and the hydrolysis acidification tank.

7. The livestock breeding high-concentration organic wastewater treatment system according to claim 1, characterized in that: The strong aeration system adopts a multi-layer aeration device, and each layer of aeration device is independently equipped with an aeration fan; or, the strong aeration system is a pure oxygen supply system.

8. The livestock breeding high-concentration organic wastewater treatment system according to claim 1, characterized in that: The rear end of the sixth sedimentation tank is sequentially provided with a coagulation and flocculation reactor, a final sedimentation tank, a deep treatment unit and a disinfection water tank.

9. A high-efficiency and low-consumption process for treating high-concentration organic wastewater from livestock breeding, characterized in that: The livestock breeding high-concentration organic wastewater treatment system according to any one of claims 1 to 8 is used for implementation, and the livestock breeding high-concentration organic wastewater treatment process comprises the following steps: After the sewage is separated into solid and liquid by the solid-liquid separation unit, the effluent suspended solids concentration SS ≤ 5000 mg / L; The effluent from the solid-liquid separation unit enters the hydrolysis and acidification tank for hydrolysis and acidification reaction. The effluent from the hydrolysis and acidification tank enters the first sedimentation tank, and the effluent from the hydrolysis and acidification tank meets the COD / TKN=6~8; 10%~30% of the effluent from the first sedimentation tank enters the primary denitrification reactor, and the rest enters the methanogenic reactor. The effluent from the methanogenic reactor enters the second sedimentation tank, and the effluent from the methanogenic reactor meets the COD / TKN < 3; The effluent from the second sedimentation tank enters the primary nitrification reactor for nitrification reaction, and the effluent from the primary nitrification reactor enters the third sedimentation tank; The effluent from the third sedimentation tank enters the primary denitrification reactor. The mixed liquid formed by the effluent from the first sedimentation tank and the effluent from the third sedimentation tank satisfies the COD / TKN=3.5~5. The mixed liquid undergoes denitrification reaction in the primary denitrification reactor. The effluent from the primary denitrification reactor enters the fourth sedimentation tank. The effluent from the fourth sedimentation tank enters the secondary nitrification reactor for nitrification reaction, and the effluent from the secondary nitrification reactor enters the fifth sedimentation tank; The effluent from the fifth sedimentation tank enters the secondary denitrification reactor for denitrification reaction. When the carbon source is insufficient, the carbon source is supplemented to the secondary denitrification reactor through external supplementation. The effluent from the secondary denitrification reactor enters the sixth sedimentation tank.

10. The livestock breeding high-concentration organic wastewater treatment process according to claim 9, characterized in that: The primary nitration reactor performs the nitration reaction according to the following operating parameters: Reaction temperature 15-40°C, dissolved oxygen concentration 5-8 mg / L, sludge concentration 10,000-20,000 mg / L, sludge age 12-22 days, sludge load 0.5-1.0 kg NH3-N / (kg MLSS·d), pH ≥ 7.0; The primary denitrification reactor performs denitrification reaction according to the following operating parameters: Reaction temperature 15~35°C, dissolved oxygen concentration 0.2~0.6mg / L, sludge concentration 5000~15000mg / L, sludge age 8~18d, sludge load 0.1-0.5kgNO3 - / (kg MLSS·d), pH value = 6.5~8.0; The secondary nitration reactor performs nitration reaction according to the following operating parameters: Reaction temperature 15-40°C, dissolved oxygen concentration 4-8 mg / L, sludge concentration 5000-10000 mg / L, sludge age 15-25 days, sludge load 0.4-0.8 kg NH3-N / (kg MLSS·d), pH ≥ 7.0; The secondary denitrification reactor performs denitrification reaction according to the following operating parameters: Reaction temperature 15~35°C, dissolved oxygen concentration 0.2~0.6mg / L, sludge concentration 3000~6000mg / L, sludge age 18~28d, sludge load 0.05~0.15kgNO3 - / (kg MLSS·d), pH value = 6.5~8.0.

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