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

Abstract

The application discloses a high-efficiency and low-consumption livestock breeding high-concentration organic sewage treatment system and process. The livestock breeding high-concentration organic sewage treatment system comprises, in sequence, a solid-liquid separation unit, a hydrolysis acidification tank, a first sedimentation tank, a methane production 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, and rear ends of the first sedimentation tank are connected with the methane production reactor and the primary denitrification reactor respectively. The system and the process do not need to rely on high multiple reflux of nitrification liquid, thereby being capable of being operated at low power consumption, and being capable of effectively saving alkali supplement and carbon supplement costs, and having the advantages of high reaction efficiency, strong anti-interference capability, simple sludge management and control and low working condition control difficulty.

Description

TECHNICAL FIELD

[0001] The application 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

[0002] The existing livestock breeding industry sewage has the characteristics of high COD, high ammonia nitrogen, high total phosphorus (TP) and high SS. The organic pollutant concentration is COD=8000-50000 mg / L, ammonia nitrogen=600-2000 mg / L, TP=100-300 mg / L, and SS (suspended solids)=5000-30000 mg / L, which is extremely difficult to treat high-concentration organic sewage.

[0003] The removal of COD must be removed by a process combining anaerobic and aerobic processes, and the efficiency of the anaerobic process alone is too low, and the energy consumption of the aerobic process alone is too large. The removal of ammonia nitrogen must be removed by a process combining aerobic and anoxic processes. In the traditional A / A / O process (anaerobic-anoxic-aerobic), sludge is circulated in the entire system through nitrification liquid reflux and sludge reflux, so the sludge in each reaction unit is mixed, rather than strictly separated. This means that the sludge in the anaerobic, anoxic and aerobic units is mixed together, but the environmental conditions in each reaction unit are different, resulting in different growth advantages of different bacterial populations. For example, nitrifying bacteria in the aerobic tank are active under aerobic conditions, while denitrifying bacteria in the anoxic tank are active under anoxic conditions, but nitrification liquid and sludge reflux will cause bacterial populations to mix. Therefore, in the traditional A / A / O process, mixed sludge is used in each reaction unit, rather than dedicated sludge, such as the proportion of denitrifying bacteria in the anoxic tank, which is 5-10%, and the proportion of nitrifying bacteria in the aerobic tank, which is only about 10-30%. This results in a low reaction rate in each reaction unit, which is easily disturbed by other reactions, and it is difficult to control the sludge age and sludge concentration, and the working condition control is very difficult.

[0004] When treating high-ammonia-nitrogen sewage, the traditional A / A / O process requires high reflux of nitrification liquid to ensure high removal rate. For example, when NH3-N>1500 mg / L, to achieve NH3-N<15 mg / L, the nitrification liquid reflux ratio needs to reach 99 times. High reflux leads to a significant increase in energy consumption, and the anoxic tank also has difficulty in denitrification reaction due to high reflux of nitrification liquid with high dissolved oxygen, and even changes to aerobic conditions. Moreover, in the aerobic unit, nitrification and carbon reduction are mutually inhibitory, and it is also difficult to ensure efficient completion of the nitrification reaction. This is the core pain point of the high-NH3-N sewage A / A / 0 process that is difficult to meet the standard operation. SUMMARY

[0005] In order to overcome the deficiencies of the prior art, the purpose of the present application is to provide a high-efficiency and low-consumption livestock breeding high-concentration organic sewage treatment system and process, which does not rely on high-multiple reflux of nitrification liquid and can operate at low power consumption, and can effectively save the cost of alkali and carbon supplement, has the advantages of high reaction efficiency, strong anti-interference ability, simple sludge control and management, and low working condition control difficulty.

[0006] The high-efficiency and low-consumption livestock breeding high-concentration organic sewage treatment system of the present application adopts the following technical scheme:

[0007] A high-efficiency and low-consumption livestock breeding high-concentration organic sewage treatment system, comprising, in sequence, a solid-liquid separation unit, a hydrolysis acidification tank, a first sedimentation tank, a methane production reactor, a second sedimentation tank, a first nitrification reactor, a third sedimentation tank, a first denitrification reactor, a fourth sedimentation tank, a second nitrification reactor, a fifth sedimentation tank, a second denitrification reactor, and a sixth sedimentation tank, the rear end of the first sedimentation tank being connected to the methane production reactor and the first denitrification reactor respectively;

[0008] The first nitrification reactor and the second nitrification reactor are each provided with a strong aeration system, and each cultivate nitrification-specific sludge; the first denitrification reactor and the second denitrification reactor are each provided with a micro-aeration system, and each cultivate denitrification-specific sludge;

[0009] The first sedimentation tank is connected to a first sludge discharge facility, the first sludge discharge facility is connected to a first sludge reflux facility, the first sludge reflux facility is connected to the hydrolysis acidification tank, the second sedimentation tank is connected to a second sludge discharge facility, the second sludge discharge facility is connected to a second sludge reflux facility, the second sludge reflux facility is connected to the methane production reactor, the third sedimentation tank is connected to a third sludge discharge facility, the third sludge discharge facility is connected to a third sludge reflux facility, the third sludge reflux facility is connected to the first nitrification reactor, the fourth sedimentation tank is connected to a fourth sludge discharge facility, the fourth sludge discharge facility is connected to a fourth sludge reflux facility, the fourth sludge reflux facility is connected to the first denitrification reactor, the fifth sedimentation tank is connected to a fifth sludge discharge facility, the fifth sludge discharge facility is connected to a fifth sludge reflux facility, the fifth sludge reflux facility is connected to the second nitrification reactor, and the sixth sedimentation tank is connected to a sixth sludge discharge facility, the sixth sludge discharge facility is connected to a sixth sludge reflux facility, and the sixth sludge reflux facility is connected to the second denitrification reactor.

[0010] Further, the nitrification-specific sludge refers to sludge in which the proportion of nitrifying bacteria in the microbial community is greater than 90%; and the denitrification-specific sludge refers to sludge in which the proportion of denitrifying bacteria in the microbial community is greater than 90%.

[0011] Further, the livestock breeding high-concentration organic sewage treatment system further comprises a sludge collecting tank, and the first, second, third, fourth, fifth and sixth sludge discharge facilities are connected with the sludge collecting tank, and the sludge collecting tank is connected with a sludge treatment system.

[0012] Further, the front end of the solid-liquid separation unit is provided with a water collecting tank, and the water collecting tank is connected with the sludge collecting tank, so that the supernatant of the sludge collecting tank can flow back to the water collecting tank.

[0013] Further, the solid-liquid separation unit adopts a multi-stage separation device, and each stage of the separation device adopts a gravity separator, a centrifugal separator or an extrusion separator.

[0014] Further, an adjusting tank is arranged between the solid-liquid separation unit and the hydrolysis acidification tank.

[0015] Further, the strong aeration system adopts a multi-layer aeration device, and each layer of the aeration device is independently provided with an aeration fan; or the strong aeration system is a pure oxygen supply system.

[0016] Further, 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 clean water tank.

[0017] The efficient and low-consumption livestock breeding high-concentration organic sewage treatment process of the present application is realized by adopting the following technical scheme:

[0018] An efficient and low-consumption livestock breeding high-concentration organic sewage treatment process is realized by adopting the above-mentioned livestock breeding high-concentration organic sewage treatment system, and the livestock breeding high-concentration organic sewage treatment process comprises the following steps:

[0019] After the sewage is subjected to solid-liquid separation by the solid-liquid separation unit, the suspended solid concentration SS of the effluent is less than or equal to 5000 mg / L;

[0020] The effluent of the solid-liquid separation unit enters the hydrolysis acidification tank to perform a hydrolysis acidification reaction, the effluent of the hydrolysis acidification tank enters the first sedimentation tank, and the effluent of the hydrolysis acidification tank satisfies COD / TKN=6-8;

[0021] 10%-30% of the effluent of the first sedimentation tank enters the first denitrification reactor, and the remaining part of the effluent enters the methanogenic reactor, the effluent of the methanogenic reactor enters the second sedimentation tank, and the effluent of the methanogenic reactor satisfies COD / TKN<3;

[0022] The effluent of the second sedimentation tank enters the first nitrification reactor to perform a nitrification reaction, and the effluent of the first nitrification reactor enters the third sedimentation tank.

[0023] The effluent of the third sedimentation tank enters a first denitrification reactor, the mixed liquid formed by the effluent of the first sedimentation tank and the effluent of the third sedimentation tank satisfies COD / TKN = 3.5-5, the mixed liquid is subjected to denitrification reaction in the first denitrification reactor, and the effluent of the first denitrification reactor enters a fourth sedimentation tank;

[0024] The effluent of the fourth sedimentation tank enters a second nitrification reactor to perform nitrification reaction, the effluent of the second nitrification reactor enters a fifth sedimentation tank;

[0025] The effluent of the fifth sedimentation tank enters a second denitrification reactor to perform denitrification reaction, when the carbon source is insufficient, the carbon source is supplemented to the second denitrification reactor by external supplement, and the effluent of the second denitrification reactor enters a sixth sedimentation tank.

[0026] Further, the first nitrification reactor performs nitrification reaction according to the following operation parameters:

[0027] The reaction temperature is 15-40°C, the dissolved oxygen concentration is 5-8 mg / L, the sludge concentration is 10000-20000 mg / L, the sludge age is 12-22 d, the sludge load is 0.5-1.0 kgNH3-N / (kg MLSS·d), and the pH value is ≥7.0;

[0028] The first denitrification reactor performs denitrification reaction according to the following operation parameters:

[0029] The reaction temperature is 15-35°C, the dissolved oxygen concentration is 0.2-0.6 mg / L, the sludge concentration is 5000-15000 mg / L, the sludge age is 8-18 d, the sludge load is 0.1-0.5 kgNO3 - / (kg MLSS·d), and the pH value is 6.5-8.0;

[0030] The second nitrification reactor performs nitrification reaction according to the following operation parameters:

[0031] The reaction temperature is 15-40°C, the dissolved oxygen concentration is 4-8 mg / L, the sludge concentration is 5000-10000 mg / L, the sludge age is 15-25 d, the sludge load is 0.4-0.8 kgNH3-N / (kg MLSS·d), and the pH value is ≥7.0;

[0032] The second denitrification reactor performs denitrification reaction according to the following operation parameters:

[0033] The reaction temperature is 15-35°C, the dissolved oxygen concentration is 0.2-0.6 mg / L, the sludge concentration is 3000-6000 mg / L, the sludge age is 18-28 d, the sludge load is 0.05-0.15 kgNO3 - / (kg MLSS·d), and the pH value is 6.5-8.0.

[0034] Compared with the prior art, the application has the beneficial effects that:

[0035] The high-efficiency and low-consumption livestock breeding high-concentration organic sewage treatment system and process provided by the application can be operated with low power consumption without relying on high multiple reflux of nitrification liquid, can effectively save alkali and carbon supplement costs, and has the advantages of high reaction efficiency, strong anti-interference capability, simple sludge control and management, and low working condition control difficulty. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 The high-efficiency and low-consumption livestock breeding high-concentration organic sewage treatment system and process provided by the application can be operated with low power consumption without relying on high multiple reflux of nitrification liquid, can effectively save alkali and carbon supplement costs, and has the advantages of high reaction efficiency, strong anti-interference capability, simple sludge control and management, and low working condition control difficulty. DETAILED DESCRIPTION

[0037] In the following, the application will be further described in combination with the drawings and specific embodiments, and it should be noted that the embodiments described below or the technical features thereof can be combined in any manner to form new embodiments without conflict.

[0038] REFERENCE Figure 1 The application provides a high-efficiency and low-consumption livestock breeding high-concentration organic sewage treatment system and process. The system and process of the application mainly include three stages: a pretreatment stage, a nitrification-denitrification stage, and a final treatment stage.

[0039] The high-efficiency and low-consumption livestock breeding high-concentration organic sewage treatment system of the application includes, in sequence, 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 is connected to the methanogenic reactor and the primary denitrification reactor.

[0040] The solid-liquid separation unit, the hydrolysis acidification tank, the first sedimentation tank, the methanogenic reactor, and the second sedimentation tank are used to construct the pretreatment stage of the application and are used for solid-liquid separation + anaerobic pretreatment process of the sewage. Specifically, the solid-liquid separation unit adopts multi-stage separation equipment, 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 finally the effluent of the solid-liquid separation unit is required to satisfy SS≤5000mg / L. If the SS is not effectively separated from the sewage, the subsequent anoxic and aerobic processes cannot be normally operated, and therefore the SS must be effectively removed in the pretreatment stage.

[0041] The anaerobic treatment of the present application adopts a modified UASB anaerobic reaction unit, which is divided into two stages, namely hydrolysis acidification tank and methanogenic reactor. Anaerobic process is the biochemical process with the lowest energy consumption for removing COD, so the removal of COD should be fully considered in anaerobic process. However, BOD in COD is a good self-sufficient carbon source for denitrification reaction, so the anaerobic unit should provide carbon source for the rear-end denitrification process, which can greatly reduce the cost of external carbon source for denitrification. On the one hand, the carbon source for denitrification should be ensured, and on the other hand, the COD should be fully degraded. Therefore, the anaerobic treatment can be divided into two stages, namely hydrolysis acidification tank and methanogenic reactor. The hydrolysis acidification tank is used for hydrolysis acidification reaction, and the methanogenic reactor realizes acetogenesis and methanogenesis. The reaction efficiency of the hydrolysis acidification tank is controlled at about 30%, ensuring that the effluent COD / TKN is 6-8, and the reaction efficiency of the methanogenic reactor is more than 80%, ensuring that the effluent COD / TKN is less than 3.

[0042] The first-stage nitrification reactor, the third sedimentation tank, the first-stage denitrification reactor, the fourth sedimentation tank, the second-stage nitrification reactor, the fifth sedimentation tank, the second-stage denitrification reactor and the sixth sedimentation tank constitute the nitrification-denitrification stage of the present application. The first-stage nitrification reactor and the second-stage nitrification reactor are each provided with a strong aeration system, and each of the first-stage nitrification reactor and the second-stage nitrification reactor is cultured with nitrification-specific sludge. The first-stage denitrification reactor and the second-stage denitrification reactor are each provided with a micro-aeration system, and each of the first-stage denitrification reactor and the second-stage denitrification reactor is provided with denitrification-specific sludge. The strong aeration system refers to an aeration system for providing a high concentration of dissolved oxygen, for example, DO=4-8 mg / L; the micro-aeration system refers to an aeration system for providing a low concentration of dissolved oxygen, for example, DO=0.2-0.6 mg / L. Specifically, the strong aeration system adopts a multi-layer aeration device, and each layer of the aeration device is independently provided 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, and the purpose of setting the micro-aeration system is to prevent the denitrification reactor from becoming an anaerobic working condition. Low concentration of dissolved oxygen helps to maintain an anoxic working condition.

[0043] The first sedimentation tank is connected with a first sludge discharge device, the first sludge discharge device is connected with a first sludge return device, the first sludge return device is connected with the hydrolysis acidification tank, the second sedimentation tank is connected with a second sludge discharge device, the second sludge discharge device is connected with a second sludge return device, the second sludge return device is connected with the methanogenesis reactor, the third sedimentation tank is connected with a third sludge discharge device, the third sludge discharge device is connected with a third sludge return device, the third sludge return device is connected with the primary nitrification reactor, the fourth sedimentation tank is connected with a fourth sludge discharge device, the fourth sludge discharge device is connected with a fourth sludge return device, the fourth sludge return device is connected with the primary denitrification reactor, the fifth sedimentation tank is connected with a fifth sludge discharge device, the fifth sludge discharge device is connected with a fifth sludge return device, the fifth sludge return device is connected with the secondary nitrification reactor, and the sixth sedimentation tank is connected with a sixth sludge discharge device, the sixth sludge discharge device is connected with a sixth sludge return device, and the sixth sludge return device is connected with the secondary denitrification reactor.

[0044] The rear end of each biological reaction unit of the application is provided with a sedimentation tank, a sludge discharge device, a sludge return device and the like for realizing sludge interception, discharge and return, so that each biological reaction unit adopts a specific sludge. For example, the nitrification reactor adopts a nitrification specific sludge, which refers to a sludge with a proportion of nitrifying bacteria in the microbial community greater than 90%; the denitrification reactor adopts a denitrification specific sludge, which refers to a sludge with a proportion of denitrifying bacteria in the microbial community greater than 90%.

[0045] The livestock breeding high-concentration organic sewage treatment system of the embodiment of the application further comprises a sludge collection tank, the first sludge discharge device, the second sludge discharge device, the third sludge discharge device, the fourth sludge discharge device, the fifth sludge discharge device and the sixth sludge discharge device are connected with the sludge collection tank, and the sludge collection tank is connected with a sludge treatment system.

[0046] In the livestock breeding high-concentration organic sewage treatment system of the embodiment of the application, the front end of the solid-liquid separation unit is provided with a water collection tank, the water collection tank is connected with the sludge collection tank, so that the supernatant of the sludge collection tank can be returned to the water collection tank, because the supernatant of the sludge collection tank does not reach the discharge standard, it needs to be returned to the water collection tank. In addition, an adjusting tank is arranged between the solid-liquid separation unit and the hydrolysis acidification tank, which can play a buffering role.

[0047] In the livestock breeding high-concentration organic sewage treatment system of the embodiment of the application, 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 clear water tank. The coagulation and flocculation reactor, the final sedimentation tank, the deep treatment unit and the disinfection clear water tank constitute the final treatment stage of the application.

[0048] The high-efficiency and low-consumption livestock breeding high-concentration organic sewage treatment process of the embodiment of the present application is realized by using the livestock breeding high-concentration organic sewage treatment system. The livestock breeding high-concentration organic sewage treatment process comprises a pretreatment step S100, a nitrification-denitrification step S200 and a final treatment step S300.

[0049] The pretreatment step S100 comprises the following sub-steps S101-S102.

[0050] S101, after the sewage is subjected to solid-liquid separation by the solid-liquid separation unit, the effluent suspended solids concentration SS is ≤5000 mg / L.

[0051] S102, the effluent of the solid-liquid separation unit enters the hydrolysis acidification tank for hydrolysis acidification reaction, the effluent of the hydrolysis acidification tank enters the first sedimentation tank, and the effluent of the hydrolysis acidification tank satisfies COD / TKN=6-8.

[0052] S103, 10%-30% of the effluent of the first sedimentation tank enters the first-stage denitrification reactor, and the rest of the effluent enters the methanogenic reactor, the effluent of the methanogenic reactor enters the second sedimentation tank, and the effluent of the methanogenic reactor satisfies COD / TKN<3. Among them, 10%-30% of the effluent of the first sedimentation tank enters the first-stage denitrification reactor, and the specific purpose is to take part of the effluent of the hydrolysis acidification tank to provide internal carbon source for the first-stage denitrification reactor. In this way, the cost of external carbon source for denitrification can be greatly reduced, which not only ensures the carbon source for denitrification, but also realizes the full degradation of COD.

[0053] The nitrification-denitrification step S200 comprises the following steps S201-S204.

[0054] S201, the effluent of the second sedimentation tank enters the first-stage nitrification reactor for nitrification reaction, and the effluent of the first-stage nitrification reactor enters the third sedimentation tank. Among them, the first-stage nitrification reactor performs nitrification reaction according to the following operation parameters: reaction temperature 15-40°C, dissolved oxygen concentration 5-8 mg / L, sludge concentration 10000-20000 mg / L, sludge age 12-22 d, sludge loading 0.5-1.0 kgNH3-N / (kg MLSS·d), pH≥7.0.

[0055] In step S201, since the COD / TKN of the sewage entering the primary nitrification reactor is less than 3, experiments show that when the COD / TKN of the sewage is less than 3.5, when the DO of the reaction tank is greater than 3.5 mg / L, the nitrification reaction will become a dominant reaction, and the carbon reduction (COD decomposition) reaction will become a weak reaction. When the dissolved oxygen DO is greater than 5 mg / L, the carbon reduction reaction will be significantly inhibited. When the dissolved oxygen of the primary nitrification reactor is set to DO = 5-8 mg / L, it can ensure that the nitrification reaction is fully completed, and the COD decomposition efficiency is controlled to be less than 3%.

[0056] Since 7.14 parts of alkalinity are lost for every one part of nitrification reaction, the alkalinity of the nitrification reactor decreases rapidly, and the pH value also decreases. In order to minimize the loss of alkalinity and affect the pH balance in the primary nitrification reactor, the influent of the primary nitrification reactor is taken from the effluent of the anaerobic second stage (i.e. the effluent of the methane-producing reactor). When 1 g of acetic acid completes the methanation reaction, the alkalinity of the sewage can be increased by 0.83 g (calculated as CaCO3). Although the hydrolysis and acidification reaction will lose alkalinity, combined with the alkalinity brought by the sewage and the alkalinity generated in the methanation stage, the alkalinity is net increased; theoretically, in an anaerobic reaction system with COD > 15000 mg / L, when the methanation stage of anaerobic reaction is completed, it can compensate for 30-40% of the alkalinity lost when 1000 mg / L of NH3-N is nitrified. This is an important reason why the influent of the primary nitrification is taken from the effluent of the anaerobic methanation.

[0057] In addition, microorganisms will regulate the pH value through endogenous respiration when the alkalinity of the nitrification reactor is insufficient; in the nitrification reaction of the traditional A / O process, the heterotrophic bacteria will compete for oxygen sources when the carbon source is sufficient, resulting in that the microorganisms cannot obtain sufficient oxygen to complete endogenous respiration to regulate the pH value, so the aerobic tank of the traditional A / O process cannot utilize endogenous respiration to supplement alkalinity; however, the nitrification process of the present application is carried out in an environment with C / TKN < 3, and uses special sludge, so the microorganisms can regulate the pH value of the environment through endogenous respiration, thereby solving the problem of external alkaline supplementation.

[0058] S202, the effluent of the third sedimentation tank enters the primary denitrification reactor, and the mixed liquid formed by the effluent of the first sedimentation tank and the effluent of the third sedimentation tank satisfies COD / TKN = 3.5-5, the mixed liquid is subjected to denitrification reaction in the primary denitrification reactor, and the effluent of the primary denitrification reactor enters the fourth sedimentation tank. The primary denitrification reactor carries out 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 d, sludge load 0.1-0.5 kgNO3 -(kg MLSS.d), pH = 6.5~8.0.

[0059] In step 202, part of the carbon source for denitrification is derived from the effluent of the anaerobic first stage (i.e. the effluent of the hydrolysis acidification tank), and there is also a carbon source with COD / TKN = 2 or so in the nitrification liquid. The COD / TKN of the mixture of the effluent of the anaerobic first stage and the nitrification liquid must be between 3.5-5, thereby determining the ratio of the nitrification liquid to the effluent of the anaerobic first stage entering the primary denitrification reactor.

[0060] In addition, because the third sedimentation tank consumes a large amount of dissolved oxygen in the nitrification liquid, in order to avoid the primary denitrification reactor becoming anaerobic, the primary denitrification reactor is provided with a micro-aeration system for maintaining the dissolved oxygen concentration at 0.2-0.6 mg / L.

[0061] Because 10%-30% of the anaerobic effluent does not undergo nitrification, the primary OA process is difficult to ensure efficient removal of ammonia nitrogen, so a secondary OA process is also provided, i.e. a secondary nitrification reactor and a secondary denitrification reactor.

[0062] S203, the effluent of the fourth sedimentation tank enters the secondary nitrification reactor for nitrification, and the effluent of 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 d, sludge load 0.4-0.8 kgNH3-N / (kg MLSS.d), pH≥7.0.

[0063] Because a large amount of carbon source is consumed by the denitrification reaction in the primary denitrification reactor, the COD / TKN of the primary denitrification effluent is <3, and as long as the dissolved oxygen DO in the secondary nitrification reactor is controlled to be between 4-6 mg / L, the nitrification reaction can be ensured to be completed effectively. In addition, the second nitrification reaction has increased the alkalinity due to the first nitrification reaction, and the problem of alkalinity can basically be solved, so there is no need to adjust through microbial endogenous respiration, and thus the dissolved oxygen can be 20-30% lower than that in the first nitrification.

[0064] S204, the effluent of the fifth sedimentation tank enters the secondary denitrification reactor for denitrification, and when the carbon source is insufficient, the secondary denitrification reactor is supplemented with an external carbon source, and the effluent of 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 d, sludge load 0.05-0.15 kgNO3 -(kgMLSS·d), pH = 6.5~8.0.

[0065] In step S204, the influent of the secondary denitrification reactor comes from the effluent of the secondary nitrification sedimentation tank, so the secondary denitrification reactor also needs to be equipped with a micro-aeration system. The carbon source of the secondary denitrification reactor needs to be supplemented externally, and the supplement amount is about 50% of the carbon source demand. The sludge age of the secondary denitrification reactor is preferably selected to be between 18-28d, so that the denitrification bacteria can use refractory organic matter as a carbon source.

[0066] The nitrification and denitrification process of the application is characterized by nitrification first and denitrification later. This combination solves the problem of high nitrification liquid reflux when denitrification is first, greatly saving energy consumption and achieving 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 to avoid the impact of high concentration of dissolved oxygen on the anoxic 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.

[0067] In addition, in order to realize one-way flow of wastewater between nitrification and denitrification, it is required that the nitrification and denitrification reactors have high reaction efficiency and anti-interference ability. Therefore, sedimentation tanks are arranged 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, so that the sludge concentration and sludge age can be easily controlled, and sludge mixing can be effectively avoided. Therefore, exclusive sludge can be used, for example, nitrification exclusive sludge is used in the nitrification reactor, so that the microorganisms in the nitrification reactor are almost nitrifying bacteria, and denitrification exclusive sludge is used in the denitrification reactor, so that the microorganisms in the denitrification reactor are almost denitrifying bacteria. The use of nitrification and denitrification exclusive sludge cultivation greatly improves the reaction efficiency and greatly reduces the interference of other reactions.

[0068] The final treatment step S300 includes: the effluent of the sixth sedimentation tank enters the coagulation and flocculation reactor, the effluent of the coagulation and flocculation reactor enters the final sedimentation tank, the effluent of the final sedimentation tank enters the advanced treatment unit, and the effluent of the advanced treatment unit enters the disinfection clear water tank.

[0069] Specifically, the functions implemented by the deep treatment unit can include: ① removal of refractory COD; ② chemical phosphorus removal; ③ removal of pathogenic microorganisms; and ④ removal of turbidity SS. Through the above two-stage nitrification and denitrification process, more than 99% of NH3-N and TN can be removed. Through the anaerobic and nitrification-denitrification process, more than 95% of COD in the wastewater can be removed. Only the non-biodegradable and the remaining carbon source supplemented by the secondary denitrification may still exist in the wastewater, and after coagulation, flocculation, deep treatment and disinfection treatment, the aquaculture wastewater can be treated to the standard above the "Urban Sewage Discharge Standard", and the safe discharge can be realized.

[0070] Compared with the prior art, the efficient and low-consumption livestock breeding high-concentration organic wastewater treatment system and process has the following advantages:

[0071] 1) The nitrification and denitrification reactor can greatly increase the sludge concentration without worrying about sludge bulking, effectively reducing the risk of sludge bulking, and the proportion of the specific bacterial population is greatly increased, so that the reaction efficiency is greatly increased (up to 10 times or more). In addition, each reaction unit is not disturbed by other reactions, so that the reaction is more smooth.

[0072] 2) More than 50% to 60% of the COD in the wastewater can be fully decomposed by anaerobic reaction, about 10% to 20% of the COD is used as a denitrification carbon source, and the COD removed by solid-liquid separation, precipitation and other physical and chemical processes is also as high as 30% or more, so that the energy consumption of the aerobic reaction is greatly reduced. Moreover, the full anaerobic reaction can recover more biogas energy. The sludge yield of anaerobic decomposition of COD is reduced by more than 2 / 3 compared with aerobic decomposition of COD. In the engineering application of the traditional A / 0 process, the C / N of the wastewater entering the A / 0 process is required to be between 5 and 7, so that 40% to 60% of the oxygen is used to decompose the COD. Therefore, the energy consumption of oxygen supply can be saved by 40% to 60%, and the sludge yield can be reduced by more than 50%.

[0073] 3) Since the system internal alkali supplement is realized, the alkali supplement cost can be effectively saved; in addition, only a small amount of carbon source needs to be supplemented in the secondary denitrification, so the actual carbon supplement cost is very low, and the carbon supplement cost is effectively solved.

[0074] 4) No high reflux of nitrification liquid is required, so the energy consumption caused by the reflux of nitrification liquid is effectively saved.

[0075] 5) Since each reaction unit is independently provided with a sedimentation tank, the sludge concentration and sludge age can be more easily controlled, and phosphorus removal can be better.

[0076] 6) The reaction process is more stable, the operation difficulty is smaller, the working condition control difficulty is lower, and the automatic operation management is more beneficial.

[0077] In conclusion, the livestock breeding high-concentration organic sewage treatment system and process provided by the application can be operated with low power consumption without relying on high-multiple reflux of nitrification liquid, can effectively save the cost of alkali and carbon supplement, has the advantages of high reaction efficiency, strong anti-interference ability, simple sludge management and control, and low working condition control difficulty, and finally realizes the purpose of high efficiency and low consumption.

[0078] The above-mentioned embodiments are only preferred embodiments of the application, and cannot be used to limit the protection scope of the application, and any non-essential changes and replacements made by those skilled in the art on the basis of the application shall belong to the protection scope of the application.

Claims

1. A high-efficiency, low-consumption livestock farming high-concentration organic wastewater treatment system, characterized in that, It includes a solid-liquid separation unit, a hydrolysis acidification tank, a first sedimentation tank, a methanogenic 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, a fifth sedimentation tank, a second-stage denitrification reactor, and a sixth sedimentation tank arranged in sequence. The rear end of the first sedimentation tank is connected to the methanogenic reactor and the first-stage denitrification reactor, respectively. Each of the primary and secondary nitrification reactors is equipped with a strong aeration system, and each of the primary and secondary nitrification reactors cultivates nitrification-specific sludge. Each of the primary and secondary denitrification reactors is equipped with a micro-aeration system, and each of the primary and secondary denitrification reactors is equipped with denitrification-specific sludge. The first sedimentation tank is connected to the first sludge discharge facility, which 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, which is connected to the second sludge return facility. The second sludge return facility is connected to the methanogenic reactor. The third sedimentation tank is connected to the third sludge discharge facility, which 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, which 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, which 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, which is connected to the sixth sludge return facility. The sixth sludge return facility is connected to the secondary denitrification reactor.

2. The livestock breeding high-concentration organic wastewater treatment system as described in claim 1, characterized in that, The nitrification-specific sludge refers to sludge in which the proportion of nitrifying bacteria in the microbial community is greater than 90%; the denitrification-specific sludge refers to sludge in which the proportion of denitrifying bacteria in the microbial community is greater than 90%.

3. The livestock breeding high-concentration organic wastewater treatment system as described in claim 1, characterized in that, The livestock breeding high-concentration organic wastewater treatment system also includes a sludge collection tank. 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.

4. The livestock breeding high-concentration organic wastewater treatment system as described in claim 1, characterized in that, The solid-liquid separation unit is equipped with a water collection tank at its front end, which is connected to the sludge collection tank so that the supernatant of the sludge collection tank can flow back to the water collection tank.

5. The livestock breeding high-concentration organic wastewater treatment system as described in claim 1, characterized in that, The solid-liquid separation unit employs multi-stage separation equipment, with each stage consisting of a gravity separator, a centrifugal separator, or a compression separator.

6. The livestock breeding high-concentration organic wastewater treatment system as described in claim 1, characterized in that, An equalization tank is provided between the solid-liquid separation unit and the hydrolysis acidification tank.

7. The livestock breeding high-concentration organic wastewater treatment system as described in claim 1, characterized in that, The high-pressure aeration system employs a multi-layer aeration device, with each layer of aeration device independently equipped with an aeration blower; or, the high-pressure aeration system is a pure oxygen supply system.

8. The livestock breeding high-concentration organic wastewater treatment system as described in claim 1, characterized in that, The sixth sedimentation tank is equipped with a coagulation and flocculation reactor, a final sedimentation tank, a deep treatment unit, and a disinfection clear water tank in sequence at its rear end.

9. A highly efficient and low-consumption process for treating high-concentration organic wastewater from livestock farming, characterized in that, This is achieved using the high-concentration organic wastewater treatment system for livestock farming as described in any one of claims 1-8, wherein the high-concentration organic wastewater treatment process for livestock farming includes the following steps: After solid-liquid separation by the wastewater solid-liquid separation unit, the effluent suspended solids concentration (SS) is ≤5000mg / L. The effluent from the solid-liquid separation unit enters the hydrolysis acidification tank for hydrolysis acidification reaction. The effluent from the hydrolysis acidification tank enters the first sedimentation tank, and the effluent from the hydrolysis acidification tank meets the COD / TKN=6~8. 10% to 30% of the effluent from the first sedimentation tank enters the first-stage denitrification reactor, and 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 requirement that COD / TKN < 3. The effluent from the second sedimentation tank enters the first-stage nitrification reactor for nitrification, and the effluent from the first-stage nitrification reactor enters the third sedimentation tank. The effluent from the third sedimentation tank enters the first-stage denitrification reactor. The mixture formed by the effluent from the first and third sedimentation tanks satisfies COD / TKN=3.5~5. This mixture undergoes denitrification in the first-stage denitrification reactor. The effluent from the first-stage denitrification reactor enters the fourth sedimentation tank. 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 effluent from the fifth sedimentation tank enters the secondary denitrification reactor for denitrification. When the carbon source is insufficient, the carbon source is supplemented to the secondary denitrification reactor through external means. The effluent from the secondary denitrification reactor enters the sixth sedimentation tank.

10. The livestock farming high-concentration organic wastewater treatment process as described in claim 9, characterized in that, The primary nitration reactor operates under the following parameters: The reaction temperature is 15~40°C, the dissolved oxygen concentration is 5~8 mg / L, the sludge concentration is 10000~20000 mg / L, the sludge age is 12~22 days, the sludge load is 0.5~1.0 kgNH3-N / (kg MLSS·d), and the pH value is ≥7.

0. The primary denitrification reactor operates under the following parameters: The reaction temperature was 15–35°C, the dissolved oxygen concentration was 0.2–0.6 mg / L, the sludge concentration was 5000–15000 mg / L, the sludge age was 8–18 days, and the sludge loading was 0.1–0.5 kg NO3. - / (kg MLSS·d), pH value = 6.5~8.0; The secondary nitration reactor operates under the following parameters: The reaction temperature is 15~40°C, the dissolved oxygen concentration is 4~8 mg / L, the sludge concentration is 5000~10000 mg / L, the sludge age is 15~25 days, the sludge load is 0.4~0.8 kgNH3-N / (kg MLSS·d), and the pH value is ≥7.

0. The secondary denitrification reactor operates under the following parameters: The reaction temperature was 15–35°C, the dissolved oxygen concentration was 0.2–0.6 mg / L, the sludge concentration was 3000–6000 mg / L, the sludge age was 18–28 days, and the sludge loading was 0.05–0.15 kg NO3. - / (kg MLSS·d), pH value = 6.5~8.0.

Images