High-density aquaculture tail water treatment system and process

Abstract

The invention discloses a high-density aquaculture tail water treatment system and process, and the treatment system comprises a sewage collection tank, a solid-liquid separator, a first sedimentation tank, a first precision filter, a nitration reaction unit, a denitrification reaction unit, a carbon reduction reaction unit, a final sedimentation tank, a second precision filter, a disinfection tank and a clean water tank which are connected in sequence, the nitration reaction unit is provided with a strong aeration system and a microorganism adding device, the denitrification reaction unit is provided with a micro aeration system and a microorganism adding device, and the carbon reduction reaction unit is provided with a strong aeration system and a microorganism adding device. The method can effectively solve the problem of treatment of high-density aquaculture tail water with huge water volume and ultra-low concentration so as to achieve the standard discharge and safe reuse standard of the tail water, so that the problem of tail water treatment is solved, water resources can be saved, the water taking cost of a farm is reduced, and the economic benefit is increased. Excrement residues, feed residues and the like subjected to solid-liquid separation can be recycled and processed into fish and shrimp fertilizers, and the economic benefits are effectively improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of sewage treatment, and particularly relates to a high-density aquaculture tail water treatment system and process. BACKGROUND

[0002] The tail water of aquaculture, especially high-density aquaculture, cannot be directly discharged due to the over-limit pollutant concentration. If the tail water is not treated in time, the excrement and feed residues of aquatic products will quickly pollute the aquaculture water. In the adult stage of aquatic products, it is necessary to ensure that the aquaculture water meets the water quality requirements for the growth of aquatic products, and the water exchange frequency is as high as more than 5 times a day, so the water consumption of high-density aquaculture is quite large. Taking shrimp culture as an example, the water consumption per mu of area per batch of shrimp exceeds 5000m 3 , and such a large amount of water needs to be effectively treated to meet the standards.

[0003] High-density aquaculture needs to ensure that the tail water meets the discharge standard and that the aquaculture water meets the water quality requirements for the growth of aquatic products. The requirements for the aquaculture water are higher than the tail water discharge standard. Because the growth of aquatic products has high requirements for the water quality of the aquaculture water, most of the indicators of the tail water concentration are slightly higher than the discharge standard, which is a field of ultra-low organic pollutant treatment. For example, the tail water concentration of a culture farm is TN<10mg / L, nitrite nitrogen: 0.1~1mg / L, nitrate nitrogen 1~3mg / L, COD<60mg / L, and most of the tail water pollutant indicators are lower than the above data. At present, different discharge standards are executed according to different culture types in China, which are Freshwater Pond Aquaculture Water Discharge Requirements (SC / T 9101-2007) and Seawater Pond Aquaculture Water Discharge Requirements (SC / T 9103-2007). In Freshwater Pond Aquaculture Water Discharge Requirements (SC / T 9101-2007), the first-level discharge standard is COD≦15mg / L, TN≦3mg / L, and TP≦0.5mg / L. In Seawater Pond Aquaculture Water Discharge Requirements (SC / T 9103-2007), the first-level discharge standard is COD≦10mg / L, inorganic nitrogen≦0.5mg / L, and active phosphate≦0.05mg / L.

[0004] High-density aquaculture tail water treatment belongs to the field of wastewater treatment with large water quantity and ultra-low concentration. Due to the low concentration of pollutants, it is difficult to cultivate active sludge by using biochemical process due to the lack of nutrients. Moreover, due to the low concentration of pollutants, the contact probability between the pollutants and the active sludge is low, and it is more difficult to effectively carry out biochemical reactions. A large number of experiments also show that even if the biochemical unit in the aquaculture tail water treatment system is provided with fillers, it is also difficult to effectively form a biofilm, so that the biochemical process is difficult to normally operate. The facilities such as sedimentation tank, filter tank and oxidation pond cannot solve the problem of total nitrogen removal in the tail water.

[0005] From the requirements of water saving and emission standards, the total nitrogen, nitrate nitrogen and nitrite nitrogen removal of tail water is the core of tail water treatment, so the anoxic process is particularly important in addition to the aerobic process. At present, the technology in the field of aquaculture tail water treatment is mainly based on the degradation of COD and nitrification, and the treatment effect of nitrate nitrogen and nitrite nitrogen in tail water is limited, which is a common problem of using biochemical process for aquaculture tail water. If the aquaculture tail water is to be treated to the reuse standard, the biological safety problem should also be fully considered. When high-density industrialized aquaculture is carried out, the tail water is uniformly treated, and if the pathogenic microorganisms are not killed when reused, cross infection will occur, which is another pain point of industrialized aquaculture.

[0006] In recent years, the state and local governments have successively introduced relevant emission standards, and the tail water treatment of aquaculture has been paid more and more attention by the government and enterprises, but so far there is no economic and feasible process technology to solve the problem of aquaculture tail water treatment. Three pools and two dams, oxidation ponds, ecological ponds, ordinary biochemical processes and traditional AAO processes cannot effectively solve the problem of tail water treatment of aquaculture. SUMMARY

[0007] In order to overcome the shortcomings of the prior art, the purpose of the present application is to provide a high-density aquaculture tail water treatment system and process, which can effectively solve the problem of high-density aquaculture tail water treatment with huge water quantity and ultra-low concentration, so as to achieve the standard discharge and safe reuse of tail water, solve the problem of tail water treatment, save water resources, reduce the water taking cost of the breeding farm, and also recycle the manure, feed residues and the like after solid-liquid separation to process into fish and shrimp fertilizer, so as to offset the cost of sewage treatment and effectively improve the economic benefit.

[0008] The high-density aquaculture tail water treatment system of the present application adopts the following technical scheme: A high-density aquaculture tail water treatment system, comprising a sewage collection pool, a solid-liquid separation machine, a first sedimentation tank, a first precision filter, a nitrification reaction unit, a denitrification reaction unit, a carbon reduction reaction unit, a final sedimentation tank, a second precision filter, a disinfection tank and a clear water tank connected in sequence, the nitrification reaction unit is provided with a strong aeration system and a microbial adding device, the denitrification reaction unit is provided with a micro-aeration system and a microbial adding device, and the carbon reduction reaction unit is provided with a strong aeration system and a microbial adding device.

[0009] High-density aquaculture tail water Further, the disinfection tank is provided with a strong oxidant adding device and an ultraviolet disinfection device.

[0010] Further, the high-density aquaculture tail water treatment system further comprises a backwashing system, the clear water pool is connected with the backwashing system, and the backwashing system is used for providing backwashing water for the backwashing system; the backwashing system is connected with the first precision filter, the nitrification reaction unit, the denitrification reaction unit, the carbon reduction reaction unit and the second precision filter respectively, and is used for providing backwashing functions for the first precision filter, the nitrification reaction unit, the denitrification reaction unit, the carbon reduction reaction unit and the second precision filter.

[0011] Further, the high-density aquaculture tail water treatment system further comprises a second sedimentation tank, and the second sedimentation tank is connected with the first precision filter, the nitrification reaction unit, the denitrification reaction unit, the carbon reduction reaction unit and the second precision filter respectively, and is used for collecting backwashing wastewater.

[0012] Further, the second sedimentation tank is connected with the sewage collection tank, so that supernatant of the second sedimentation tank can flow back to the sewage collection tank.

[0013] Further, the nitrification reaction unit is filled with fillers, the denitrification reaction unit is filled with fillers, and the carbon reduction reaction unit is filled with fillers.

[0014] Further, the filling rate of the fillers in the nitrification reaction unit is 70% to 90%, the filling rate of the fillers in the denitrification reaction unit is 70% to 90%, and the filling rate of the fillers in the carbon reduction reaction unit is 70% to 90%.

[0015] Further, the strong oxygen 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 oxygen aeration system is a pure oxygen supply system.

[0016] The high-density aquaculture tail water treatment process of the application is implemented by using the following technical scheme: The high-density aquaculture tail water treatment process comprises the following steps: The effluent of the sewage collection tank is treated by the solid-liquid separation machine and then enters the first sedimentation tank; The effluent of the first sedimentation tank enters the first precision filter; The effluent of the first precision filter enters the nitrification reaction unit, the dissolved oxygen concentration of the nitrification reaction unit is controlled to be 4 to 6 mg / L, the microbial flora is supplemented to the nitrification reaction unit in a field instant adding mode, and the proportion of nitrifying bacteria in the microbial flora is greater than 90%; The effluent of the nitrification reaction unit enters the denitrification reaction unit, the dissolved oxygen concentration of the denitrification reaction unit is controlled to be 0.2 to 0.6 mg / L, the microbial flora is supplemented to the denitrification reaction unit in a field instant adding mode, and the proportion of denitrifying bacteria in the microbial flora is greater than 90%. The effluent of the denitrification reaction unit enters the carbon reduction reaction unit, the dissolved oxygen concentration of the carbon reduction reaction unit is controlled to be 4-6 mg / L, and the microbial flora is supplemented to the carbon reduction reaction unit in a form of on-site instant addition, and the carbon reduction bacteria in the microbial flora account for more than 90%; The effluent of the denitrification reaction unit enters the final sedimentation tank; The effluent of the final sedimentation tank enters the disinfection tank; The effluent of the disinfection tank enters the clear water tank.

[0017] Compared with the prior art, the beneficial effects of the present application are that: The high-density aquaculture tail water treatment system and process provided by the present application can effectively solve the problem of tail water treatment of high-density aquaculture with huge water volume and ultra-low concentration, so as to achieve the standards of tail water discharge and safe recycling, solve the problem of tail water treatment, save water resources, reduce the water taking cost of the breeding farm, and recycle the manure residue, feed residue and the like after solid-liquid separation to process into fish and shrimp fertilizer, so as to offset the cost of sewage treatment and effectively improve the economic benefit. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 It is a schematic diagram of the high-density aquaculture tail water treatment system and process of the embodiments of the present application. DETAILED DESCRIPTION

[0019] In the following, the present application will be further described in combination with the drawings and specific embodiments, and it should be noted that the following described embodiments or technical features can be combined in any manner to form new embodiments without conflict.

[0020] Reference Figure 1 The embodiments of the present application provide a high-density aquaculture tail water treatment system and a high-density aquaculture tail water treatment process realized by using the system.

[0021] The high-density aquaculture tail water treatment system of the embodiments of the present application comprises a sewage collection tank, a solid-liquid separation machine, a first sedimentation tank, a first precision filter, a nitrification reaction unit, a denitrification reaction unit, a carbon reduction reaction unit, a final sedimentation tank, a second precision filter, a disinfection tank and a clear water tank connected in sequence, the nitrification reaction unit is provided with a strong aeration system and a microbial adding device, the denitrification reaction unit is provided with a micro-aeration system and a microbial adding device, and the carbon reduction reaction unit is provided with a strong aeration system and a microbial adding device. The strong aeration system is used to provide a higher concentration of dissolved oxygen, for example, 4-6 mg / L; the micro-aeration system is used to provide a lower concentration of dissolved oxygen, for example, 0.2-0.6 mg / L; and the microbial adding device is used to add microbial colonies to the corresponding reaction unit in a form of on-site instant addition.

[0022] The present application embodiment is provided with a nitrification reaction unit, a denitrification reaction unit and a carbon reduction reaction unit, which are respectively used for carrying out nitrification reaction, denitrification reaction and carbon reduction reaction, so as to solve the problem that the existing aquaculture tail water technology lacks denitrification treatment.

[0023] The high-density aquaculture tail water treatment belongs to the field of sewage treatment with huge water quantity and ultra-low concentration. Since the concentration of pollution factors is low, the required reaction time is short under the condition of ensuring the concentration of microbial flora is sufficient. The short reaction time helps to improve the sewage treatment efficiency to adapt to the situation of huge water quantity. The low concentration of pollution factors leads to less nutrient source suitable for microorganisms in the system, and it is very difficult to maintain the concentration of microorganisms by domestication of the system. Therefore, the microbial flora in the nitrification, denitrification and carbon reduction reaction units are added in situ to supplement the amount of microorganisms. The microbial flora should select the nitrification, denitrification and carbon reduction flora with high proportion as the added bacteria. In order to reduce the cost of bacteria, a microbial expansion and adding device can also be set on site, so that the microorganisms can be precisely cultured and the cost of microbial adding can be reduced.

[0024] In the high-density aquaculture tail water treatment system of the present application embodiment, the disinfection tank is used for disinfecting and killing pathogens in the water body to solve the problem of microbial safety. The disinfection tank is provided with a combination of strong oxidant adding device and ultraviolet disinfection device. The strong oxidant used can be ozone and chlorine dioxide.

[0025] In the high-density aquaculture tail water treatment system of the present application embodiment, in order to ensure the stability of the effluent water quality, the precision filter and each biochemical reaction unit should be periodically backwashed. Specifically, the high-density aquaculture tail water treatment system further comprises a backwashing system, and a clean water tank connected to the backwashing system, which is used to provide backwashing water for the backwashing system. The backwashing system is connected with the first precision filter, the nitrification reaction unit, the denitrification reaction unit, the carbon reduction reaction unit and the second precision filter, respectively, and is used to provide backwashing function for the first precision filter, the nitrification reaction unit, the denitrification reaction unit, the carbon reduction reaction unit and the second precision filter.

[0026] Obviously, the backwashing wastewater cannot necessarily meet the discharge or reuse standards, so the high-density aquaculture tail water treatment system further comprises a second sedimentation tank, which is connected with the first precision filter, the nitrification reaction unit, the denitrification reaction unit, the carbon reduction reaction unit and the second precision filter, respectively. The second sedimentation tank is used to collect backwashing wastewater, and the second sedimentation tank is connected with a sewage collection tank, so that the supernatant of the second sedimentation tank can be backflowed to the sewage collection tank.

[0027] In order to further improve the efficiency of biochemical reaction, in the high-density aquaculture tail water treatment system, the nitration reaction unit is filled with fillers, the denitrification reaction unit is filled with fillers, and the carbon reduction reaction unit is filled with fillers. The filler filling rate of the nitration reaction unit is 70%-90%, the filler filling rate of the denitrification reaction unit is 70%-90%, and the filler filling rate of the carbon reduction reaction unit is 70%-90%. The fillers are preferably granular, have good water absorption, are not easy to wear, and have a large specific surface area, so as to ensure that the microorganisms and pollution factors are in full contact.

[0028] In the high-density aquaculture tail water treatment system, the strong oxygen 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 oxygen aeration system is a pure oxygen supply system.

[0029] The high-density aquaculture tail water treatment process is realized by using the high-density aquaculture tail water treatment system, and the high-density aquaculture tail water treatment process comprises the following steps S1-S8.

[0030] S1, the effluent of the sewage collection tank is treated by the solid-liquid separation machine and then enters the first sedimentation tank.

[0031] S2, the effluent of the first sedimentation tank enters the first precision filter.

[0032] The fecal residue and feed residue separated by the first sedimentation tank and the solid-liquid separation machine can be recycled and processed into fish and shrimp fertilizer. In theory, 5000 tons of fish and shrimp fertilizer can be processed per hundred mu of high-density aquaculture farm. The fish and shrimp fertilizer has high content of amino acids and high nutrients, and the added value is greater than that of ordinary organic fertilizer. The recycled fish and shrimp fertilizer can offset the cost of sewage treatment and effectively improve the economic benefit.

[0033] S3, the effluent of the first precision filter enters the nitration reaction unit, the dissolved oxygen concentration of the nitration reaction unit is controlled to be 4-6 mg / L, the microbial flora is supplemented to the nitration reaction unit in a real-time manner, and the proportion of nitrifying bacteria in the microbial flora is greater than 90%.

[0034] S4, the effluent of the nitration reaction unit enters the denitrification reaction unit, the dissolved oxygen concentration of the denitrification reaction unit is controlled to be 0.2-0.6 mg / L, the microbial flora is supplemented to the denitrification reaction unit in a real-time manner, and the proportion of denitrifying bacteria in the microbial flora is greater than 90%.

[0035] S5, the effluent of the denitrification reaction unit enters the carbon reduction reaction unit, the dissolved oxygen concentration of the carbon reduction reaction unit is controlled to be 4-6 mg / L, the microbial flora is supplemented to the carbon reduction reaction unit in a real-time manner, and the proportion of carbon reduction bacteria in the microbial flora is greater than 90%.

[0036] S6, the effluent of the denitrification reaction unit enters a final sedimentation tank.

[0037] S7, the effluent of the final sedimentation tank enters a disinfection tank.

[0038] S8, the effluent of the disinfection tank enters a clear water tank; the effluent of the clear water tank can be used as backwashing water or used as aquaculture water body recycling to solve the water resource.

[0039] In summary, the high-density aquaculture tail water treatment system and process provided by the application can effectively solve the problem of tail water treatment of high-density aquaculture with huge water volume and ultra-low concentration, so as to achieve the standard of tail water discharge and safe recycling, solve the problem of tail water treatment, save water resources, reduce the cost of water intake of the aquaculture farm, and recycle the manure residue, feed residue and the like after solid-liquid separation to process into fish and shrimp fertilizer, so as to offset the cost of sewage treatment and effectively improve the economic benefit.

[0040] 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 all belong to the protection scope of the application.

Claims

1. A high-density aquaculture wastewater treatment system, characterized in that, The system includes a wastewater collection tank, a solid-liquid separator, a first sedimentation tank, a first precision filter, a nitrification reaction unit, a denitrification reaction unit, a carbon reduction reaction unit, a final sedimentation tank, a second precision filter, a disinfection tank, and a clear water tank, all connected in sequence. The nitrification reaction unit is equipped with a strong aeration system and a microbial dosing device, the denitrification reaction unit is equipped with a micro-aeration system and a microbial dosing device, and the carbon reduction reaction unit is equipped with a strong aeration system and a microbial dosing device.

2. The high-density aquaculture wastewater treatment system as described in claim 1, characterized in that, The disinfection pool is equipped with a strong oxidant dosing device and an ultraviolet disinfection device.

3. The high-density aquaculture wastewater treatment system as described in claim 1, characterized in that, The high-density aquaculture wastewater treatment system also includes a backwashing system. The clear water tank is connected to the backwashing system to provide backwashing water for the backwashing system. The backwashing system is connected to the first precision filter, the nitrification reaction unit, the denitrification reaction unit, the carbon reduction reaction unit, and the second precision filter to provide backwashing function for the first precision filter, the nitrification reaction unit, the denitrification reaction unit, the carbon reduction reaction unit, and the second precision filter.

4. The high-density aquaculture wastewater treatment system as described in claim 3, characterized in that, The high-density aquaculture wastewater treatment system also includes a second sedimentation tank, which is connected to the first precision filter, the nitrification reaction unit, the denitrification reaction unit, the carbon reduction reaction unit, and the second precision filter, respectively, for collecting backwash wastewater.

5. The high-density aquaculture wastewater treatment system as described in claim 4, characterized in that, The second sedimentation tank is connected to the sewage collection tank so that the supernatant from the second sedimentation tank can be returned to the sewage collection tank.

6. The high-density aquaculture wastewater treatment system as described in claim 1, characterized in that, The nitration reaction unit is filled with packing material, the denitration reaction unit is filled with packing material, and the carbon reduction reaction unit is filled with packing material.

7. The high-density aquaculture wastewater treatment system as described in claim 6, characterized in that, The packing filling rate of the nitration reaction unit is 70%~90%, the packing filling rate of the denitrification reaction unit is 70%~90%, and the packing filling rate of the carbon reduction reaction unit is 70%~90%.

8. The high-density aquaculture wastewater treatment system as described in claim 1, characterized in that, The strong oxygen aeration system employs a multi-layer aeration device, with each layer of aeration device independently equipped with an aeration blower; or, the strong oxygen aeration system is a pure oxygen supply system.

9. A high-density aquaculture wastewater treatment process, characterized in that, This is achieved using the high-density aquaculture wastewater treatment system as described in any one of claims 1-8, wherein the high-density aquaculture wastewater treatment process includes the following steps: The effluent from the sewage collection tank is treated by a solid-liquid separator and then enters the first sedimentation tank. The effluent from the first sedimentation tank enters the first precision filter; The effluent from the first precision filter enters the nitrification reaction unit, where the dissolved oxygen concentration is controlled at 4~6 mg / L. Microbial communities are added to the nitrification reaction unit on-site in real time, with nitrifying bacteria accounting for more than 90% of the microbial communities. The effluent from the nitrification unit enters the denitrification unit, where the dissolved oxygen concentration is controlled at 0.2~0.6 mg / L. Microbial communities are added to the denitrification unit on-site, with denitrifying bacteria accounting for more than 90% of the microbial community. The effluent from the denitrification unit enters the carbon reduction unit, where the dissolved oxygen concentration is controlled at 4-6 mg / L. Microbial communities are added to the carbon reduction unit on-site, with carbon-reducing bacteria accounting for more than 90% of the microbial community. The effluent from the denitrification reaction unit enters the final settling tank; The effluent from the final sedimentation tank enters the disinfection tank; The effluent from the disinfection pool flows into the clear water pool.

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