An integrated water treatment system for circulating aquaculture and tailwater treatment

Abstract

The present invention provides a circulating aquaculture and tailwater treatment integrated water treatment system, including a sewage collection tank, a physical filtration device, an electrode-suspended filler coupled biofilter treatment unit, and an ozone-ultraviolet combined pathogenic microorganism killing pool connected in sequence, wherein the sewage collection tank, the physical filtration device, the electrode-suspended filler coupled biofilter treatment unit, and the ozone-ultraviolet combined pathogenic microorganism killing pool are all connected to a sludge concentration and dehydration device, and the ozone-ultraviolet combined pathogenic microorganism killing pool is also connected to a breeding pool. The present invention has high water treatment efficiency and can continuously maintain the excellent water quality of the breeding system, and the water recycling rate can reach 95% to 98%; it can not only fully meet the healthy breeding needs of the breeding objects, but also has a tailwater treatment function, and can achieve tailwater discharge up to standard.

Description

[Technical field]

[0001] The invention relates to a water treatment system integrating circulating aquaculture and tail water treatment. [Background technology]

[0002] Recirculating aquaculture has developed rapidly in recent years, and the scale of aquaculture has been expanding. The main species of freshwater recirculating aquaculture include eel, sturgeon, cod, tilapia and vannamei shrimp, which has the advantages of water saving, land saving, high yield, high efficiency and high-quality and safe aquatic products. Although many of them can achieve a daily water recycling rate of more than 90%, and even the highest water recycling rate at the international leading level can reach 97%. However, generally there is still about 10% of relatively high concentration wastewater (mainly backwash water or sewage from the treatment unit during the water treatment process, high-concentration nitrogen and phosphorus sludge water containing residual bait, feces, detached biofilm, etc.) tail water that needs to be discharged from the system every day. In addition to using a filter press or other particulate sludge concentration and dehydration equipment to concentrate and dehydrate the wastewater to form a mud cake for external transportation, the remaining majority of the wastewater (≥98%) contains high concentrations of total nitrogen (generally >5mg / L) and total phosphorus (generally >1mg / L), that is, the discharged tail water generated by the recirculating aquaculture system exceeds the emission standards specified in the "Freshwater Aquaculture Tail Water Discharge Requirements" (SC / T9101), and also exceeds the Class III water quality standards in the national "Surface Water Environmental Quality Standards" (GB3838-2002). At present, the tailwater generated by the recirculating aquaculture system is basically discharged directly into the surrounding waters without treatment. Very few of them build ecological ponds, artificial wetlands or use chemical agents for flocculation and sedimentation to achieve standard discharge. However, it requires additional land area, equipment and facility investment and operating costs. Many farms are unable to carry out tailwater discharge treatment due to land area restrictions and high treatment costs, polluting the surrounding water environment or facing the problem of forced suspension of production due to non-compliance with environmental protection standards.

[0003] The current circulating aquaculture water treatment system mainly designs water treatment processes and constructs corresponding water treatment units based on the biological characteristics, ecological habits and safety concentration requirements of the main water quality factors such as ammonia nitrogen and nitrite nitrogen of the aquaculture objects (such as fish and shrimp), so that the water quality of the circulating aquaculture water can meet the healthy aquaculture needs of the aquaculture objects and achieve the healthy growth of the aquaculture objects. However, it does not have the function of treating the tail water to meet the discharge standards. [Summary of the invention]

[0004] The technical problem to be solved by the present invention is to provide an integrated water treatment system for recirculating aquaculture and tailwater treatment, which has the characteristics of high water treatment efficiency and can continuously maintain the excellent water quality of the aquaculture system. The water recycling rate can reach 95% to 98%; it can not only fully meet the healthy breeding needs of the aquaculture objects and achieve the healthy growth of the aquaculture objects, but also has the tailwater treatment function, which can achieve the tailwater discharge that meets the standards.

[0005] The present invention is achieved in that:

[0006] A circulating aquaculture and tailwater treatment integrated water treatment system, the water treatment system comprising a sewage collection tank, a physical filtration device, an electrode-suspended filler coupled biofilter treatment unit, an ozone-ultraviolet combined pathogenic microorganism killing pool and a sludge concentration and dehydration device; the sewage collection tank is connected to the physical filtration device, the physical filtration device is connected to the electrode-suspended filler coupled biofilter treatment unit, the electrode-suspended filler coupled biofilter treatment unit is adjacent to the ozone-ultraviolet combined pathogenic microorganism killing pool, the sewage collection tank, the physical filtration device, the electrode-suspended filler coupled biofilter treatment unit, the ozone-ultraviolet combined pathogenic microorganism killing pool are all connected to the sludge concentration and dehydration device, and the ozone-ultraviolet combined pathogenic microorganism killing pool is also connected to the aquaculture tank;

[0007] The electrode-suspended filler coupled biofilter treatment unit comprises a biofilter, a suspended filler, a DC positive and negative electrode array combination, an electric stirring device and a carbon source supplement device, wherein the suspended filler is arranged in the biofilter, the DC positive and negative electrode array combination is arranged at the upper part of the biofilter, the electric stirring device is arranged at the lower part of the biofilter, a sludge hopper is arranged at the bottom of the biofilter, the electric stirring device is arranged above the sludge hopper, and the carbon source supplement device is connected to the biofilter through a pipeline;

[0008] The volume ratio of the suspended filler to the water in the biofilter is 20% to 50%, and the density of the suspended filler is 0.92 to 0.98 g / cm 3 ; The anode in the DC positive and negative electrode array combination is iron, and the cathode is iron, carbon or copper; the speed of the electric stirring device is 100 to 300 r / min.

[0009] Furthermore, the suspended filler is made of high-density polyethylene with a specific surface area greater than 500m 2 / m 3 .

[0010] Furthermore, the spacing between adjacent electrodes of the DC positive and negative electrode array combination is 2-30 cm, and the operating voltage and current are: DC voltage is 12-36 V, and micro-current density is 0.1-1.0 mA / cm 2 .

[0011] Furthermore, the biofilter is a combination of more than two tank bodies connected in series, and a DC positive and negative electrode array combination can be set in part or all of the tank bodies.

[0012] Furthermore, the physical filtering device is an automatic backwashing screen filter, a microfilter or a curved screen.

[0013] Furthermore, the ozone-ultraviolet combined pathogenic microorganism killing pool comprises an ozone pool and an ultraviolet lamp-oxygenation pool arranged adjacent to each other, a microporous aeration plate is arranged at the bottom of the ozone pool, and the microporous aeration plate is connected to an ozone generator outside the pool body; an ultraviolet lamp is arranged at the top of the ultraviolet lamp-oxygenation pool, an oxygenation microporous tube is arranged at the bottom of the ultraviolet lamp-oxygenation pool, and the oxygenation microporous tube is connected to an air pump outside the pool body, the water inlet of the ultraviolet lamp-oxygenation pool is arranged at the bottom, and the water outlet is arranged at the top; a sludge hopper is arranged at the bottom of the ozone pool and the ultraviolet lamp-oxygenation pool, and the sludge hopper is connected to a sludge concentration and dehydration device.

[0014] Furthermore, the ozone generator inputs ozone to treat the water body 4 to 12 times a day, and each time lasts for 20 to 60 minutes; the hydraulic retention time in the ultraviolet lamp-oxygenation pool is 15 to 40 minutes.

[0015] Furthermore, the ultraviolet lamp is arranged in an immersed manner.

[0016] The present invention has the following advantages:

[0017] In summary, the present invention mainly achieves continuous, stable and efficient phosphorus and nitrogen removal, organic matter degradation and suspended solids concentration reduction effects through a series of physical, chemical and microbial effects generated in the biofilter, integrated iron cation phosphate precipitation reaction, iron cation hydrate and its polymer flocculation precipitation of phosphorus and other particulate matter, nitrification reaction and denitrification reaction, etc. The device has the advantages of simple structure, small amount of sludge production and no secondary pollution.

[0018] The present invention realizes the dual functions of circulating aquaculture water treatment and tail water discharge treatment in an integrated manner, and has the advantages of land saving, high water treatment efficiency, low investment and operation cost, and simple management. The present invention has the characteristics of high water treatment efficiency and can continuously maintain the excellent water quality of the aquaculture system, and the water recycling rate can reach 95% to 98%; it can not only fully meet the healthy aquaculture needs of the aquaculture objects and realize the healthy growth of the aquaculture objects, but also has the tail water treatment function and can realize the tail water discharge in compliance with the standards. It solves the problem that the current circulating aquaculture water treatment system has a single function and does not have the tail water discharge treatment capacity in compliance with the standards.

Brief Description of the Drawings

[0019] The present invention will be further described below in conjunction with embodiments with reference to the accompanying drawings.

[0020] Figure 1 It is a structural schematic diagram of the present invention.

[0021] Figure 2 It is a schematic diagram of the coordinated structure of the electrode-suspended filler coupling biofilter treatment unit and the ozone-ultraviolet combined pathogenic microorganism killing pool in the present invention. [Specific implementation method]

[0022] See also Figure 1-2 The present invention relates to an integrated water treatment system for circulating aquaculture and tailwater treatment, the water treatment system comprising a sewage collection tank 1, a physical filtration device 2, an electrode-suspended filler coupled biological filter treatment unit 3, an ozone ultraviolet combined pathogenic microorganism killing pool 4 and a sludge concentration and dehydration device 5; the sewage collection tank 1 is connected to the physical filtration device 2, the physical filtration device 2 is connected to the electrode-suspended filler coupled biological filter treatment unit 3, the electrode-suspended filler coupled biological filter treatment unit 3 is adjacent to the ozone ultraviolet combined pathogenic microorganism killing pool 4, the sewage collection tank 1, the physical filtration device 2, the electrode-suspended filler coupled biological filter treatment unit 3, the ozone ultraviolet combined pathogenic microorganism killing pool 4 are all connected to the sludge concentration and dehydration device 5, and the ozone ultraviolet combined pathogenic microorganism killing pool 4 is also connected to the aquaculture tank 6;

[0023] The electrode-suspended filler coupled biofilter treatment unit 3 comprises a biofilter 31, a suspended filler 32, a DC anode-cnode electrode array combination 33, an electric stirring device 34 and a carbon source supplement device 35, wherein the suspended filler 32 is arranged in the biofilter 31, the DC anode-cnode electrode array combination 33 is arranged at the upper part of the biofilter 31, the electric stirring device 34 is arranged at the lower part of the biofilter 31, a sludge hopper 7 is arranged at the bottom of the biofilter 31, the electric stirring device 34 is arranged above the sludge hopper 7, and the carbon source supplement device 35 is connected to the biofilter 31 through a pipeline;

[0024] The volume ratio of the suspended filler 32 to the water in the biofilter 31 is 20% to 50%, and the density of the suspended filler 32 is 0.92 to 0.98 g / cm 3 The anode of the DC positive and negative electrode array combination 33 is iron, and the cathode is iron, carbon or copper; the rotation speed of the electric stirring device 34 is 100 to 300 r / min.

[0025] The suspended filler 32 is made of high-density polyethylene with a specific surface area greater than 500m 2 / m 3 .

[0026] The spacing between adjacent electrodes of the DC positive and negative electrode array combination 33 is 2-30 cm, and the operating voltage and current are: DC voltage is 12-36 V, and micro-current density is 0.1-1.0 mA / cm 2 .

[0027] The biofilter 31 is a combination of two or more tank bodies connected in series, and a DC positive and negative electrode array combination 33 can be set on part or all of the tank bodies.

[0028] The physical filtering device 2 is an automatic backwashing screen filter, a microfilter or a curved screen.

[0029] The ozone-ultraviolet combined pathogenic microorganism killing pool 4 comprises an ozone pool 41 and an ultraviolet lamp-oxygenation pool 42 which are adjacently arranged. A microporous aeration disk 411 is arranged at the bottom of the ozone pool 41, and the microporous aeration disk 411 is connected to an ozone generator outside the pool body; an ultraviolet lamp 421 is arranged at the top of the ultraviolet lamp-oxygenation pool 42, and an oxygenation microporous tube 422 is arranged at the bottom of the ultraviolet lamp-oxygenation pool 42, and the oxygenation microporous tube 422 is connected to an air pump outside the pool body. The water inlet of the ultraviolet lamp-oxygenation pool 42 is arranged at the bottom, and the water outlet is arranged at the top; a sludge hopper 7 is arranged at the bottom of the ozone pool 41 and the ultraviolet lamp-oxygenation pool 42, and the sludge hopper 7 is connected to a sludge concentration and dehydration device 5.

[0030] The ozone generator inputs ozone to treat the water body 4 to 12 times a day, and each time lasts for 20 to 60 minutes; the hydraulic retention time in the ultraviolet lamp-oxygenation pool 42 is 15 to 40 minutes.

[0031] The ultraviolet lamp 421 is arranged in an immersed manner.

[0032] The working process of the present invention is as follows: after the aquaculture tail water enters the sewage collection tank 1, it is pumped into the physical filtering device 2 by a water pump, and the filtered water enters the electrode-suspended filler coupled biological filter treatment unit 3, while the backwash water (≤1.5%) containing large particles such as residual bait and feces enters the sludge concentration and dehydration device 5; in the sludge concentration and dehydration device 5, the concentrated and dehydrated sludge is formed into mud cake organic fertilizer and transported out of the system, and the concentrated and filtered water is returned to the sewage collection tank 1 or discharged out of the system; in the electrode-suspended filler coupled biological filter treatment unit In element 3, a sludge hopper 7 is provided at the bottom of the biological filter 31, which can discharge sewage regularly, and the sludge water (≤3%) is discharged into the sludge concentration and dehydration device 5; the water treated by the electrode-suspended filler coupled biological filter treatment unit 3 flows into the ozone ultraviolet combined pathogenic microorganism killing pool 4 to kill pathogenic microorganisms and moderately increase oxygen to obtain purified water, and the purified water flows back to the breeding pool; the ozone ultraviolet combined pathogenic microorganism killing pool 4 is provided with a sludge hopper 7, which can discharge sewage regularly, and the sludge water (≤0.5%) is discharged into the sludge concentration and dehydration device 5.

[0033] The working principle of each device is as follows:

[0034] 1. The sewage collection pool 1 is mainly used to collect the tail water discharged from all the breeding pools. More than two submersible pumps (one of which is a spare) are installed in the pool to pump the pool water to the physical filtration device 2.

[0035] 2. The physical filtration device 2 is a physical filtration device such as an automatic backwashing screen filter, a microfilter or an arc screen, which separates large particles in the water and automatically sends backwash water (≤1.5%) containing large particles such as leftover bait and feces into the sludge dewatering and concentration device 5, while the water after being filtered by the screen enters the electrode-suspended filler coupled biological filter treatment unit 3.

[0036] 3. The working principle of the electrode-suspended filler coupled biofilter treatment unit 3 is as follows:

[0037] (1) Due to the DC electric field of the DC anode and cathode electrode array combination 33, a large amount of iron cations are generated from the iron (anode), and a large amount of Fe 2+ and Fe 3+ It reacts with the phosphate in the aquaculture tail water to form granular, insoluble substances that settle in the bottom sludge hopper 7 of the biological filter 31; at the same time, the iron cation undergoes a series of hydrolysis and polymerization reactions, Fe 2+ and Fe 3+ and their hydrates such as ferric hydroxide have strong flocculation and precipitation effects on phosphorus, and can also generate polymers with adsorption and condensation effects, such as some Fe 3+ Hydrolysis produces [Fe2(OH)2] 4+ 、[Fe3(OH)4] 5+ 、[Fe5(OH)9] 6+ The polynuclear hydroxyl complexes can act as flocculants and can precipitate with some suspended matter (including suspended phosphorus, including biological phosphorus and insoluble phosphate particles), particulate matter and electrolytes in the aquaculture tail water, and settle in the sludge hopper 7 at the bottom of the biological filter 31.

[0038] (2) The dissolved oxygen contained in the aquaculture tail water and the oxygen generated by the electrolysis of water by the iron anode can provide the dissolved oxygen required for the nitrification reaction for a large number of nitrite and nitrifying bacteria in the biofilm attached to the suspended filler 32, so that ammonia nitrogen is converted into nitrite nitrogen and nitrate nitrogen. Therefore, there is no need to set up an air pump for oxygenation; at the same time, due to the rapid consumption of dissolved oxygen, the water in the pool, especially the lower layer of the pool water, quickly forms an anoxic or anaerobic water environment, which promotes the denitrification reaction.

[0039] (3) The heterotrophic denitrifying bacteria in the pool use the organic carbon source in the aquaculture water as an electron donor to cause a denitrification reaction, so that the nitrate nitrogen is eventually converted into nitrogen gas through the denitrification reaction and overflows the system to be removed.

[0040] (4) The hydrogen produced by cathode electrolysis of water can serve as an electron donor for hydrogen autotrophic denitrifying bacteria, while the CO2 in the tail water can provide an inorganic carbon source for these autotrophic bacteria, leading to autotrophic denitrification, causing nitrate nitrogen to generate nitrogen through denitrification and overflow the system to be removed.

[0041] In addition, the hydrogen generated by the electrolysis of water can stimulate the growth and metabolism of the autotrophic denitrifying bacteria attached to the surface of the suspended filler 32. At the same time, the redox substances generated by the electrolysis provide a suitable environment for the growth and reproduction of microorganisms, and provide inorganic carbon sources and electron donors for the denitrification process of the autotrophic denitrifying bacteria, further promoting the autotrophic denitrification process, thereby improving the removal of total nitrogen.

[0042] (5) Using the density of the suspended filler 32 (0.92 to 0.98 g / cm 3 ) is close to fresh water, and is easy to form a uniform suspension state in the water body of the biological filter. At the same time, under the continuous slow stirring of the electric stirring device 34 and the flow of water, a fluidized state can be formed, so that the biofilm attached to the suspended filler 32 is easy to continuously flow and contact with the pollutants in the aquaculture wastewater, which not only helps to increase the rate of nitrification and denitrification reactions, but also facilitates the continuous friction between the suspended filler 32 and the water flow and the flow through the electrode surface. The density is 0.92-0.98 g / cm at the same volume. 3 The suspended filler has greater friction and can better remove the oxides on the surface of the (anode) iron, preventing the surface of the (anode) iron from being passivated by the formation of a dense covering layer of oxides, which affects the normal progress of the electrode electrolysis reaction, and effectively solves the passivation problem of the (anode) iron.

[0043] (6) Microcurrent can strengthen the bacteria and other microorganisms in the biofilm on the suspended filler 32, change the permeability of the bacterial cell membrane, and help the enzymes in the bacterial cell membrane to pass through the cell membrane into the wastewater to carry out a series of enzymatic reactions, thereby increasing the contact between the enzymes in the cell membrane and the reaction substrates in the water, thereby enhancing the effect of degrading nitrogen and phosphorus in the aquaculture wastewater to a certain extent; in addition, microcurrent can also directly stimulate and strengthen the activity of extracellular enzymes secreted by certain bacteria, promoting the degradation of nitrogen, phosphorus and other pollutants in the water.

[0044] (7) Since the organic carbon concentration in the aquaculture tail water is generally low and will be consumed soon, in order to promote the heterotrophic denitrification reaction in the pool, a carbon source such as brown sugar is added through the carbon source supplement device 35. An automatic dosing device can be configured to regularly add a certain amount of brown sugar to the solution barrel, start the agitator to dissolve it, and then automatically add a certain amount of brown sugar to the pool through the metering pump through the pipeline to continuously and quickly promote the heterotrophic denitrification reaction.

[0045] Since the reaction rate of heterotrophic denitrification is several times (about 7 times) faster than that of autotrophic denitrification, and the population growth and expansion rate of heterotrophic denitrifying bacteria are higher than that of autotrophic denitrifying bacteria, adding organic carbon sources such as brown sugar can significantly accelerate denitrification.

[0046] The removal rate of TP has a certain positive correlation with the removal rate of TN, that is, when the TN removal effect is good, the TP removal effect is also good. In the present invention, the iron electrode can provide the electrons required for the denitrification reaction, has a certain strengthening effect on denitrification, and promotes NO3 - The decrease in the mass concentration of -N and TN is conducive to promoting the biological phosphorus removal of polyphosphate bacteria in the filler biofilm and in the water body, and synergistically promoting the removal of TP. In addition, the supplementary carbon source efficient denitrification device used in the present invention greatly promotes the continuous progress of denitrification and promotes NO3 - -N and TN mass concentrations decreased. The continuous deep removal of TP concentration was promoted synergistically. Therefore, the electrode-suspended filler coupling technology of the present invention is integrated with the carbon source supplementation technology to efficiently promote denitrification, and they work together to improve the efficiency and removal rate of nitrogen and phosphorus removal.

[0047] 4. The sludge concentration and dehydration device 5 adopts a sludge filter press or sets up a filter layer drying tank facility to form a mud cake (organic fertilizer) from the concentrated and dehydrated sludge and transport it out of the system, and the filtered water is returned to the sewage collection tank 1 or discharged out of the system.

[0048] 5. The ozone-ultraviolet combined pathogenic microorganism killing pool 4 is formed by combining an ozone pool 41 and an ultraviolet lamp-oxygenation pool 42. The combined pool is adjacent to the electrode-suspended filler coupled biofilter treatment unit 3. The water treated by the electrode-suspended filler coupled biofilter treatment unit 3 flows into the ozone pool 41. A microporous aeration disk 411 is set in the lower layer or bottom layer of the water body in the ozone pool 41. The ozone generator outside the pool is connected to the ozone generator through a pipeline. Ozone is input regularly every day (generally 4 to 12 times a day) to treat the water body. The single ozone treatment lasts for 20 to 60 minutes.

[0049] The treated water flows into the ultraviolet lamp-oxygenation pool 42, an immersed ultraviolet lamp 421 is arranged in the middle and upper layers of the water body in the pool, or an ultraviolet lamp 421 is arranged in the upper layer, and an oxygenation microporous tube 422 is arranged in the bottom layer. The oxygenation microporous tube 422 is connected to the air pump outside the pool through a pipeline, and air is input into the oxygenation microporous tube 422 to oxygenate the pool water. At the same time, the continuously generated tiny bubbles can clean the outer quartz tube wall of the ultraviolet lamp 421 to prevent attachments from adhering and maintain high ultraviolet transmittance; the pool water in the ultraviolet lamp-oxygenation pool 42 flows from bottom to top at a certain flow rate, generates an upward flow, and flows through the ultraviolet light zone constructed by the combination of the ultraviolet lamp 421. In the ultraviolet light zone, the ozone in the water can generate hydroxyl self-oxidizing agents with stronger oxidizing properties under the irradiation of ultraviolet rays. Hydroxyl free radicals will quickly react with oxidizable substances in water to accelerate the decomposition of ozone. Since hydroxyl free radicals have stronger oxidizing properties than ozone, they can deeply oxidize and quickly react with oxidizable substances in water, thereby achieving a stronger ability to kill bacteria, viruses, fungi, microalgae, parasites, eggs and spores in water, and at the same time, efficiently remove the residual ozone concentration in the water, avoiding the residual ozone concentration from entering the breeding pond with the effluent and endangering the breeding animals; the hydraulic retention time HRT of the water treatment in the ultraviolet lamp-oxygenation pool 42 is about 15 to 40 minutes, and the treated purified water is collected from the water collection pipe set at the water outlet of the upper part of the pool and then connected to the drainage pipe to flow out and return to the breeding pool 6. In addition, a sludge hopper 7 is set at the bottom of the ozone pool 41 and the ultraviolet lamp-oxygenation pool 42 for settling sludge in the water, and a sludge discharge pipe is set in the sludge hopper 7 to regularly discharge the sewage containing sludge to the sludge concentration and dehydration device 5.

[0050] The present invention is further described below in conjunction with specific embodiments.

[0051] By using the above method and device, a water treatment system integrating circulating aquaculture and tailwater treatment was constructed and applied to eel circulating aquaculture. The water recycling rate was as high as 98%. The monitoring results are as follows:

[0052]

[0053] In the above table, aquaculture pond water refers to the water quality of the water in the aquaculture pond in the circulating water aquaculture system during the aquaculture period; treated effluent refers to the purified water quality after treatment by the ozone ultraviolet combined pathogenic microorganism sterilization pool 4; external drainage refers to the filtered water after sludge concentration and dehydration treatment by the sludge concentration and dehydration device 5, which can be discharged outside the system.

[0054] From the data in the table, we can see that during the breeding period, the water quality in the breeding ponds in the recirculating aquaculture system can meet the Class III water quality standards in the national "Surface Water Environmental Quality Standards" (GB3838-2002) and the national "Fishery Water Quality Standards" (GB11607-1989); the water quality of the discharged water out of the system can meet the Class III water quality standards in the national "Surface Water Environmental Quality Standards" (GB3838-2002) and the first-level emission standards specified in the "Freshwater Aquaculture Tail Water Discharge Requirements" (SC / T 9101).

[0055] In summary, the present invention mainly achieves continuous, stable and efficient phosphorus and nitrogen removal, organic matter degradation and suspended solids concentration reduction effects through a series of physical, chemical and microbial effects generated in the biofilter, integrated iron cation phosphate precipitation reaction, iron cation hydrate and its polymer flocculation precipitation of phosphorus and other particulate matter, nitrification reaction and denitrification reaction, etc. The device has the advantages of simple structure, small amount of sludge production and no secondary pollution.

[0056] The present invention realizes the dual functions of circulating aquaculture water treatment and tail water discharge treatment in an integrated manner, and has the advantages of land saving, high water treatment efficiency, low investment and operation cost, and simple management. The present invention has the characteristics of high water treatment efficiency and can continuously maintain the excellent water quality of the aquaculture system, and the water recycling rate can reach 95% to 98%; it can not only fully meet the healthy aquaculture needs of the aquaculture objects and realize the healthy growth of the aquaculture objects, but also has the tail water treatment function and can realize the tail water discharge in compliance with the standards. It solves the problem that the current circulating aquaculture water treatment system has a single function and does not have the tail water discharge treatment capacity in compliance with the standards.

[0057] Although the specific implementation modes of the present invention are described above, those skilled in the art should understand that the specific implementation modes described are only illustrative and are not intended to limit the scope of the present invention. Equivalent modifications and changes made by those skilled in the art in accordance with the spirit of the present invention should be included in the scope of protection of the claims of the present invention.

Claims

1. A circulating aquaculture and tailwater treatment integrated water treatment system, characterized by: The water treatment system comprises a sewage collection tank, a physical filtration device, an electrode-suspended filler coupled biofilter treatment unit, an ozone-ultraviolet combined pathogenic microorganism killing pool and a sludge concentration and dehydration device; the sewage collection tank is connected to the physical filtration device, the physical filtration device is connected to the electrode-suspended filler coupled biofilter treatment unit, the electrode-suspended filler coupled biofilter treatment unit is arranged adjacent to the ozone-ultraviolet combined pathogenic microorganism killing pool, the sewage collection tank, the physical filtration device, the electrode-suspended filler coupled biofilter treatment unit, the ozone-ultraviolet combined pathogenic microorganism killing pool are all connected to the sludge concentration and dehydration device, and the ozone-ultraviolet combined pathogenic microorganism killing pool is also connected to the breeding pool; The electrode-suspended filler coupled biofilter treatment unit comprises a biofilter, a suspended filler, a DC positive and negative electrode array combination, an electric stirring device and a carbon source supplement device, wherein the suspended filler is arranged in the biofilter, the DC positive and negative electrode array combination is arranged at the upper part of the biofilter, the electric stirring device is arranged at the lower part of the biofilter, a sludge hopper is arranged at the bottom of the biofilter, the electric stirring device is arranged above the sludge hopper, and the carbon source supplement device is connected to the biofilter through a pipeline; The volume ratio of the suspended filler to the water in the biofilter is 20% to 50%, and the density of the suspended filler is 0.92 to 0.98 g / cm 3 The suspended filler forms a uniform suspension in the water of the biofilter. At the same time, under the continuous slow stirring of the electric stirring device and the flow of water, a fluidized state is formed. The suspended filler and the water flow continuously rub against and flow through the electrode surface to remove the oxide on the surface of the anode iron. The anode of the DC cathode electrode array combination is iron, and the cathode is iron, carbon or copper; the spacing between adjacent electrodes of the DC cathode electrode array combination is 2-30 cm, and the operating voltage and current are: DC voltage is 12-36 V, and micro-current density is 0.1-1.0 mA / cm 2 ; The speed of the electric stirring device is 100~300r / min; Microcurrent can strengthen the bacterial microorganisms in the biofilm on the suspended filler, change the permeability of the bacterial cell membrane, and allow the enzymes in the bacterial cell membrane to pass through the cell membrane into the wastewater for a series of enzymatic reactions, increasing the contact between the enzymes in the cell membrane and the reaction substrates in the water, thereby enhancing the effect of degrading nitrogen and phosphorus in aquaculture wastewater; in addition, microcurrent directly stimulates the activity of the extracellular enzymes secreted by the strengthening bacteria, promoting the degradation of nitrogen, phosphorus and other pollutants in the water; The ozone-ultraviolet combined pathogenic microorganism killing pool comprises an ozone pool and an ultraviolet lamp-oxygenation pool arranged adjacent to each other, a microporous aeration disk is arranged at the bottom of the ozone pool, and the microporous aeration disk is connected to an ozone generator outside the pool body; an ultraviolet lamp is arranged at the top of the ultraviolet lamp-oxygenation pool, an oxygenation microporous tube is arranged at the bottom of the ultraviolet lamp-oxygenation pool, and the oxygenation microporous tube is connected to an air pump outside the pool body, a water inlet of the ultraviolet lamp-oxygenation pool is arranged at the bottom, and a water outlet is arranged at the top; a sludge hopper is arranged at the bottom of the ozone pool and the ultraviolet lamp-oxygenation pool, and the sludge hopper is connected to a sludge concentration and dehydration device; The ozone generator inputs ozone to treat the water body 4 to 12 times a day, and each time lasts for 20 to 60 minutes; the hydraulic retention time in the ultraviolet lamp-oxygenation pool is 15 to 40 minutes.

2. The integrated water treatment system for circulating aquaculture and tailwater treatment according to claim 1 is characterized by: The suspended filler is made of high-density polyethylene with a specific surface area greater than 500m 2 / m 3 .

3. The integrated water treatment system for circulating aquaculture and tailwater treatment according to claim 1 is characterized by: The biological filter is a combination of more than two tank bodies connected in series, and a direct current positive and negative electrode array combination can be set in part or all of the tank bodies.

4. The integrated water treatment system for circulating aquaculture and tailwater treatment according to claim 1 is characterized by: The physical filtering device is an automatic backwashing screen filter, a microfilter or a curved screen.

5. The integrated water treatment system for circulating aquaculture and tailwater treatment according to claim 1 is characterized by: The ultraviolet lamp is arranged in an immersed manner.

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