Aquaculture tail water high-efficiency phosphorus removal system and method

Abstract

The present application relates to a kind of aquaculture tail water efficient phosphorus removal system and method.The system includes the pretreatment equipment, sedimentation tank, ozone oxidation equipment, carbon source supplementing equipment, membrane biological reaction equipment and ecological pond connected in sequence;The ozone oxidation equipment includes ozone oxidation reactor, catalyst dosing device and ozone generator;The biological membrane reaction system includes membrane bioreactor, and the membrane bioreactor is provided with bacteria and algae filler layer and micro-nano bubble generator.The present application is handled to aquaculture tail water by the pretreatment equipment, sedimentation tank, ozone oxidation equipment, carbon source supplementing equipment and membrane biological reaction equipment connected in sequence, carbon source is supplemented in time to tail water after ozone oxidation treatment, aeration is carried out by micro-nano bubble generator during microbial degradation processing, to promote tail water reoxygenation, guarantee the aerobic biochemical action of bacteria and algae in membrane bioreactor, to realize efficient denitrification and phosphorus removal.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of water treatment, and in particular to a high-efficiency phosphorus removal system and method for aquaculture tail water. BACKGROUND

[0002] With the rapid development of aquaculture industry, industrialized high-density aquaculture technology has been widely used. Compared with domestic sewage and industrial wastewater, although the active phosphate concentration in aquaculture tail water is low, a large amount of phosphorus elements in the untreated aquaculture tail water is discharged into the water environment, which may cause eutrophication in the receiving water body and cause certain negative impact on the ecological environment.

[0003] The purification and standard discharge of current aquaculture tail water have become a hot spot in agricultural environmental science. There is a serious lack of small-scale pond in-situ remediation technology and nitrogen and phosphorus comprehensive reduction technology in the scale tail water treatment area of contiguous ponds. In the existing aquaculture tail water purification technology, single physical, chemical or physical method often has the disadvantages of low pollutant removal efficiency, poor running stability, easy secondary pollution, etc. Therefore, physical, chemical and biological methods are combined. The traditional biological treatment denitrification route considers that denitrification must occur in anoxic or anaerobic environment. However, the DO in aquaculture water is generally maintained at 4-8 mg / L, so in the process of recirculating aquaculture, nitrate accumulation in the water body is serious, and the highest nitrate accumulation amount can reach more than 500 mg / L.

[0004] The existing aquaculture tail water treatment technology has the following defects: (1) often without setting reoxygenation or using ordinary aeration, the reoxygenation efficiency is difficult to meet the needs of stable operation of the system, the efficiency of tail water denitrification and phosphorus removal is insufficient, and the effluent cannot be recycled; (2) often using single strain for biochemical phosphorus removal, which is affected by external environment and activity of functional bacteria, and the stability of phosphorus removal is poor, resulting in high operation and maintenance cost of equipment; (3) using single chemical method for phosphorus removal, which is easy to cause secondary pollution. SUMMARY

[0005] The present application relates to the technical field of water treatment, and in particular to a high-efficiency phosphorus removal system and method for aquaculture tail water.

[0006] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is:

[0007] In a first aspect, the present application provides an efficient phosphorus removal system for aquaculture tail water, which comprises, in sequence, a pretreatment device, a sedimentation tank, an ozone oxidation device, a carbon source supplementing device, a membrane biological reaction device and an ecological pond; the ozone oxidation device comprises an ozone oxidation reactor, a catalyst dosing device and an ozone generator, the top of the ozone reactor is provided with a catalyst inlet and an ozone inlet, the catalyst dosing device is internally provided with catalysts, the outlet of the catalyst dosing device is connected with the catalyst inlet through a pipeline, and the ozone output end of the ozone generator is connected with the ozone inlet through a pipeline; the carbon source supplementing device comprises a carbon source supplementing tank, a stirrer and a carbon source dosing device, and the carbon source dosing device is used for dosing carbon sources into the carbon source supplementing tank; the biological membrane reaction system comprises a membrane biological reactor, the membrane biological reactor is internally provided with a bacteria-algae filler layer and a micro-nano bubble generator, and the micro-nano bubble generator is located below the bacteria-algae filler layer.

[0008] In the present application, the pretreatment device, the sedimentation tank, the ozone oxidation device, the carbon source supplementing device and the membrane biological reaction device are connected in sequence, the aquaculture tail water is pretreated by the pretreatment device and then enters the sedimentation tank, after being deposited in the sedimentation tank, the effluent of the sedimentation tank enters the ozone oxidation reactor, under the action of the catalyst, the organic pollutants in the aquaculture tail water are oxidized by ozone; the effluent of the ozone oxidation device enters the carbon source supplementing tank, the carbon source dosing device is used for dosing carbon sources into the carbon source supplementing tank, the carbon source is stirred by the stirrer, so that the carbon source and the aquaculture tail water are uniformly mixed, the supplemented carbon source can ensure that the functions in the subsequent membrane biological reaction device are uniformly exerted to better biochemical degradation, and the denitrification and phosphorus removal effect of the system on the tail water is improved; the aquaculture tail water after supplementing the carbon source enters the membrane biological reactor, the micro-nano bubble generator releases micro-nano bubbles, the micro-nano bubbles can promote the reoxygenation of the tail water, ensure the aerobic biochemical action of the bacteria-algae, and at the same time, the micro-nano bubbles rise in the tail water, break and generate high-energy ions in the rising process, the high-energy ions react with the pollutants in the tail water, so as to further promote the degradation of the microorganisms.

[0009] As a preferred embodiment of the present application, the pretreatment device comprises a pretreatment tank, the pretreatment tank is internally provided with a filter chamber, the filter chamber is internally provided with a grid, the bottom of the filter chamber is provided with an effluent outlet which is communicated with the pretreatment tank, and the pretreatment tank is internally provided with a lifting pump; one side of the top of the sedimentation tank is provided with a water inlet, one side of the bottom of the sedimentation tank is provided with an effluent outlet, and the effluent end of the lifting pump is connected with the water inlet of the sedimentation tank through a pipeline.

[0010] In the present application, the aquaculture tail water is collected into the filter chamber through a collection pipe network, is intercepted through the grid, and the large-size suspended pollutants in the aquaculture tail water are removed, the aquaculture tail water after the filtration through the grid flows into the pretreatment tank and is lifted into the sedimentation tank through the lifting pump.

[0011] As a preferred embodiment of the present application, the ozone oxidation reactor is provided with at least three staggered baffles, which divide the internal space of the ozone oxidation reactor into a tortuous flow channel, the ozone oxidation reactor is provided with a water inlet on one side of the upper portion, the other side of the ozone oxidation reactor is provided with a water outlet, and the water inlet of the ozone oxidation reactor is connected to the water outlet of the sedimentation tank by a pipeline. The present application divides the internal space of the ozone oxidation reactor into a tortuous flow channel by baffles, and the aquaculture tail water flows along the flow channel, so that the catalyst, ozone and aquaculture tail water are fully mixed, which is conducive to improving the oxidation and decomposition efficiency of organic pollutants.

[0012] Further, the catalyst inlet is located between the first end baffle of the at least three staggered baffles and the water inlet of the ozone oxidation reactor. The present application sets the catalyst inlet on the water inlet side of the ozone oxidation reactor, and after the catalyst enters the ozone oxidation reactor, it flows along the flow channel in the ozone oxidation reactor with the aquaculture tail water, and ozone is filled by the ozone generator, so that the pollutants in the water react with ozone under the catalytic action of the catalyst, macromolecular pollutants are oxidized by ozone into small molecular pollutants, organic nitrogen is oxidized by ozone into ammonia nitrogen, and organic phosphorus is oxidized by ozone into phosphate, which is conducive to improving the aquaculture tail water treatment efficiency of subsequent equipment.

[0013] As a preferred embodiment of the present application, the water inlet of the carbon source supplement tank is communicated with the water outlet of the ozone oxidation reactor, the agitator comprises a driving motor, an agitating mechanism and a rotating shaft, the driving motor is arranged outside the carbon source supplement tank, the agitating mechanism is arranged in the carbon source supplement tank, one end of the rotating shaft is connected to the output end of the driving motor, and the other end of the rotating shaft is connected to the agitating mechanism.

[0014] As a preferred embodiment of the present application, the membrane bioreactor is provided with a water inlet and a water outlet, and the water inlet of the membrane bioreactor is communicated with the water outlet of the carbon source supplement tank.

[0015] As a preferred embodiment of the present application, the bacteria-algae filler layer comprises a carrier, the carrier is loaded with probiotics and algae, and the probiotics comprise at least one of bacillus and photosynthetic bacteria.

[0016] Further, the carrier is a biochar carrier, which is mixed by wood chips, coconut shells and coal powder. The weight ratio of the wood chips, coconut shells and coal powder is wood chips: coconut shells: coal powder = (1-3) : (2-5) : 10.

[0017] Compared with the conventional high polymer filler, the raw material cost of the biochar carrier is low, and the raw material is easy to obtain, and after long-term operation failure, the resource can be recycled and reused; the specific surface area of the biochar carrier is large, which can provide sufficient growth space for algae, which is beneficial to the full contact of the loaded bacteria with the pollutants in the tail water, and can effectively solve the problems of bacteria loss and insufficient degradation efficiency of pollutants in the prior art.

[0018] Further, the algae include at least one of chlorella and cryptomonas. Chlorella and cryptomonas have a wide temperature range, can maintain good enzyme activity, have strong metabolism, and can effectively degrade organic pollutants in tail water.

[0019] Further, the thickness of the bacteria-algae filler layer is 100-150 cm.

[0020] As a preferred embodiment of the present application, the water inlet of the ecological pond is connected to the water outlet of the membrane bioreactor by a pipeline, a filter membrane layer and an aquatic plant area are arranged in the ecological pond, the filter membrane layer is located below the aquatic plant area, and the water inlet of the ecological pond is located below the aquatic plant area.

[0021] In the present application, the aquaculture tail water degraded by microorganisms enters the ecological pond, the pollutants in the aquaculture tail water are degraded by the aquatic plants and their root bacterial flora in the aquatic plant area, and the phosphorus is adsorbed by the filter membrane layer below to ensure that the phosphorus content of the effluent meets the requirements of recycling.

[0022] Further, the thickness of the filter membrane layer is 10-20 cm.

[0023] Further, the filter membrane layer is stacked by several iron-based MOF composite filter membranes, and the mass percentage of iron-based MOF material in the iron-based MOF composite filter membrane is 1-10%. The iron-based MOF composite filter membrane has good adsorption performance for phosphate in water, and the iron-based MOF material will not be lost with water, and has good stability.

[0024] Further, the water outlet of the ecological pond is connected to the water inlet of the ozone oxidation reactor by a reflux pipeline and a reflux pump.

[0025] Further, the ecological pond is provided with a water outlet pipe, the water outlet pipe is connected to a circulation channel, and the circulation channel is connected to the aquaculture pond.

[0026] In a second aspect, the present application provides an efficient phosphorus removal method for aquaculture tail water, which is implemented by the efficient phosphorus removal system for aquaculture tail water of the first aspect, and the efficient phosphorus removal method for aquaculture tail water comprises the following steps:

[0027] S1, inputting the aquaculture tail water into a pretreatment device for pretreatment;

[0028] S2, inputting the tail water treated by step S1 into a sedimentation tank for sedimentation treatment;

[0029] S3, inputting the tail water treated by step S2 into an ozone oxidation reactor, adding catalysts and inputting ozone, and performing ozone oxidation treatment on the tail water inputted into the ozone oxidation reactor;

[0030] S4, inputting the tail water treated by step S3 into a carbon source supplement tank, supplementing carbon sources and stirring;

[0031] S5, inputting the tail water treated by step S4 into a membrane bioreactor for microbial degradation treatment and simultaneously performing aeration treatment;

[0032] S6, inputting the tail water treated by step S5 into an ecological pond for adsorption degradation treatment.

[0033] As a preferred embodiment of the present application, in step S3, the hydraulic retention time of the ozone oxidation reactor is 15-30 min, the ratio between the input amount of the catalyst and the volume of the tail water is 0.5-1.0 g / L, and the flow rate of the ozone is 0.5-1.0 g / L.

[0034] As a preferred embodiment of the present application, in step S4, the carbon-nitrogen ratio of the tail water supplemented with carbon sources is (4-6):1.

[0035] As a preferred embodiment of the present application, in step S5, the aeration amount during aeration treatment is 5-20 m 3 / h.

[0036] As a preferred embodiment of the present application, after step S6, the tail water treated by step S6 is further backflowed into the ozone oxidation reactor, and the backflow ratio is (1-2):1.

[0037] The backflow ratio of the present application refers to the ratio between the backflow amount of the tail water treated by step S6 and the input amount of the tail water treated by step S2, and the units of the backflow amount and the input amount are both L.

[0038] Compared with the prior art, the present application has the following beneficial effects:

[0039] The present application sequentially connects a pretreatment device, a sedimentation tank, an ozone oxidation device, a carbon source supplementing device and a membrane biological reaction device, the aquaculture tail water is pretreated by the pretreatment device and then enters the sedimentation tank, after being deposited in the sedimentation tank, the effluent of the sedimentation tank enters the ozone oxidation reactor, and the organic pollutants in the aquaculture tail water are oxidized by ozone; the effluent of the ozone oxidation device enters the carbon source supplementing tank to supplement carbon source, the aquaculture tail water after supplementing carbon source enters the membrane biological reactor, the micro-nano bubble generator releases micro-nano bubbles, the micro-nano bubbles can promote the reoxygenation of the tail water, ensure the aerobic biochemical action of bacteria and algae, and also can oxidize the organic pollutants in the tail water, and the effluent of the membrane biological reaction device enters the ecological pond for further adsorption and degradation, so that efficient nitrogen and phosphorus removal is realized. BRIEF DESCRIPTION OF DRAWINGS

[0040] Figure 1 A structure schematic diagram of the water aquaculture tail water efficient phosphorus removal system provided by the present application is provided.

[0041] Figure 2 A flow chart of the water aquaculture tail water efficient phosphorus removal method provided by the present application is provided.

[0042] In the figure, 1 is a pretreatment tank, 2 is a filter chamber, 3 is a grid, 4 is a lifting pump, 5 is a sedimentation tank, 6 is an ozone oxidation reactor, 7 is a partition plate, 8 is a catalyst adding device, 9 is an ozone generator, 10 is a carbon source supplementing tank, 11 is a stirrer, 12 is a carbon source adding device, 13 is a membrane biological reactor, 14 is a bacteria and algae filler layer, 15 is a micro-nano bubble generator, 16 is an ecological pond, 17 is a filter membrane layer, 18 is an aquatic plant area, and 19 is an aquaculture pond. DETAILED DESCRIPTION

[0043] In order to better illustrate the purposes, technical solutions and advantages of the present application, the present application will be further described below in combination with specific embodiments.

[0044] The specific preparation method of the iron-based MOF composite filter membrane in the following examples is as follows: the iron-based MOF material is added to a beaker containing N,N-dimethylacetamide (DMF), and ultrasonic oscillation is performed at room temperature for 10 min to uniformly disperse the MOF powder. The beaker is transferred to a 80℃ constant temperature water bath, and polyvinylidene fluoride (PVDF) powder is slowly added under continuous stirring. The beaker is placed in a constant temperature heating magnetic stirrer, and stirred at 80℃ for 12 h in a constant temperature water bath. After fully mixing, a bright orange homogeneous casting solution with good fluidity and no undissolved particles is obtained. The prepared casting solution is left to stand at room temperature for 12 h to remove bubbles. The defoaming treated casting solution is slowly poured onto a flat non-woven fabric, the height of the doctor blade of the coating machine is controlled, and a membrane with a thickness of 300 μm is obtained. After volatilizing in air for 1 min, the membrane is quickly immersed in pure water for solidification. After membrane preparation, the membrane is taken out, and the membrane surface is washed with a large amount of pure water to fully remove residual solvent. The composite filter membrane is stored in pure water at room temperature.

[0045] The iron-based MOF material is prepared by the following method: reduced iron powder (Fe), trimesic acid, hydrofluoric acid, nitric acid and pure water are placed in a hydrothermal reaction kettle in a molar ratio of 1.0:0.67:2.0:0.6:277, and hydrothermal reaction is carried out at 150℃ for 12 h, and then naturally cooled to room temperature. The obtained material is transferred from the reaction kettle to a beaker, washed in 80℃ pure water for 3 h, then filtered, and the filtered material is washed in 60℃ anhydrous ethanol solution for 3 h, filtered and dried in an oven at 100℃ for 12 h to obtain a bright orange solid powder, which is the iron-based MOF material.

[0046] Example 1

[0047] The present embodiment provides a high-efficiency phosphorus removal system for aquaculture tail water, and the structure thereof is shown in Figure 1

[0048] The high-efficiency phosphorus removal system for aquaculture tail water comprises a pretreatment device, a sedimentation tank 5, an ozone oxidation device, a carbon source supplementing device, a membrane bioreactor device and an ecological pond 16.

[0049] Specifically, the pretreatment device comprises a pretreatment tank 1, a filter chamber 2 is arranged in the pretreatment tank 1, a grid 3 is arranged in the filter chamber 2, a water outlet is arranged at the bottom of the filter chamber 2 and communicates with the pretreatment tank 1, and a lifting pump 4 is arranged in the pretreatment tank 1. The aquaculture tail water is collected into the filter chamber 2 through the collection pipe network, intercepted by the grid 3 to remove large-size suspended pollutants in the aquaculture tail water, and flows into the pretreatment tank 1 and is lifted into the sedimentation tank 5 through the lifting pump.

[0050] ​Specifically, the water inlet is arranged at the upper side of the sedimentation tank 5, the water outlet is arranged at the lower side of the sedimentation tank 5, the water outlet end of the lifting pump 4 is connected with the water inlet of the sedimentation tank 5 through a pipeline, and the bottom of the sedimentation tank 5 is provided with a communicating sedimentation hopper. After water inlet sedimentation, the sediment is deposited in the sedimentation hopper at the bottom, and the tail water at the upper portion is discharged from the water outlet.

[0051] Specifically, the ozone oxidation equipment comprises an ozone oxidation reactor 6, a catalyst adding device 8 and an ozone generator 9. The ozone oxidation reactor 6 is provided with at least three staggered baffles 7. The interval between any two adjacent baffles 7 is 40-50 cm. The baffles 7 divide the internal space of the ozone oxidation reactor 6 into a tortuous flow channel.

[0052] The water inlet of the ozone oxidation reactor 6 is connected with the water outlet of the sedimentation tank 5 through a pipeline. The top of the ozone oxidation reactor 6 is provided with a catalyst inlet and an ozone inlet. The catalyst inlet is located between the first baffle 7 and the water inlet of the ozone oxidation reactor 6. The catalyst adding device 8 is provided with catalysts. The outlet of the catalyst adding device 8 is connected with the catalyst inlet through a pipeline. The ozone output end of the ozone generator 9 is connected with the ozone inlet through a pipeline. The catalyst inlet is arranged at the water inlet side of the ozone oxidation reactor 6. During the flow of the aquaculture tail water in the flow channel of the ozone oxidation reactor 6, the catalyst is filled with ozone by the ozone generator 9. The pollutants in the water are reacted with ozone under the catalytic action of the catalyst. The macromolecular pollutants are oxidized into small molecular pollutants by ozone. The organic nitrogen is oxidized into ammonia nitrogen by ozone. The organic phosphorus is oxidized into phosphate by ozone. This is conducive to improving the aquaculture tail water treatment efficiency of the subsequent equipment.

[0053] Specifically, the carbon source supplementing equipment comprises a carbon source supplementing tank 10, a stirrer 11 and a carbon source adding device 12. The water inlet of the carbon source supplementing tank 10 is communicated with the water outlet of the ozone oxidation reactor 6. The stirrer 11 comprises a driving motor, a stirring mechanism and a rotating shaft. The driving motor is arranged outside the carbon source supplementing tank 10. The stirring mechanism is arranged inside the carbon source supplementing tank 10. One end of the rotating shaft is connected with the output end of the driving motor. The other end of the rotating shaft is connected with the stirring mechanism. The carbon source adding device 12 is used for adding carbon source to the carbon source supplementing tank 10. The water outlet of the ozone oxidation equipment enters the carbon source supplementing tank 10. The carbon source is added to the carbon source supplementing tank 10 by the carbon source adding device 12. The carbon source and the aquaculture tail water are uniformly mixed by the stirrer 11. The supplemented carbon source can ensure that the functions in the subsequent membrane biological reaction equipment are uniformly exerted to better biochemical degradation effect, thereby improving the denitrification and phosphorus removal effect of the system on the tail water.

[0054] Specifically, the biofilm reaction system comprises a membrane bioreactor 13, the membrane bioreactor 13 is provided with a water inlet and a water outlet, the water inlet of the membrane bioreactor 13 is communicated with the water outlet of the carbon source supplementing tank 10, the membrane bioreactor 13 is provided with a bacteria-algae filler layer 14 and a micro-nano bubble generator 15, and the micro-nano bubble generator 15 is located below the bacteria-algae filler layer 14.

[0055] The thickness of the bacteria-algae filler layer 14 is 100-150 cm, and the bacteria-algae filler layer 14 is prepared by the following method:

[0056] The bacillus powder, photosynthetic bacteria concentrate, algal liquid and sterile water are mixed to prepare a bacteria-algae mixed suspension, the ratio between the mass of the bacillus powder and the volume of the bacteria-algae mixed suspension is 5-15 g / L, the volume ratio between the photosynthetic bacteria concentrate and the bacteria-algae mixed suspension is 0.005-0.015, and the volume ratio between the algal liquid and the bacteria-algae mixed suspension is 0.01-0.04;

[0057] The sawdust, coconut shell and coal powder are mixed according to the weight ratio of sawdust: coconut shell: coal powder = (1-3) : (2-5) : 10 to obtain a biochar carrier;

[0058] The biochar carrier is autoclaved and then added into the bacteria-algae mixed suspension, the volume ratio between the biochar carrier and the bacteria-algae mixed suspension is (1-5) g: 200 mL, the pH value is adjusted to 6.8-7.2, and the mixture is incubated at 28-32℃ and 100-200 r / min for 16-32 h, then filtered and washed with sterile saline for 2-4 times to obtain an immobilized body.

[0059] The obtained immobilized body is added into a sodium alginate solution with a mass concentration of 1-5%, the ratio between the mass of the immobilized body and the volume of the sodium alginate solution is 1 g: (10-30) mL, the mixture is uniformly mixed and then loaded into a syringe, and then added dropwise into a calcium chloride solution with a mass concentration of 3-6%, the molar ratio between the sodium alginate and the calcium chloride is 1: (2-3), after the dropwise addition is completed, the mixture is crosslinked for 3-8 h, then filtered and washed with sterile water to obtain the bacteria-algae filler.

[0060] In the embodiment, the algal liquid comprises at least one of chlorella liquid and cryptomonas liquid, and chlorella and cryptomonas have a wide temperature range and can maintain good enzyme activity.

[0061] The biochar carrier has a large specific surface area and can provide sufficient growth space for the bacteria-algae. The breeding tail water after the carbon source is supplemented enters the membrane bioreactor 13, the micro-nano bubble generator 15 releases micro-nano bubbles, the micro-nano bubbles can promote the reoxygenation of the tail water and ensure the aerobic biochemical action of the bacteria-algae, and meanwhile, the micro-nano bubbles break during the rising process in the tail water to generate high-energy ions, the high-energy ions react with the pollutants in the tail water, thereby further promoting the degradation of the microorganisms.

[0062] Specifically, the water inlet of the ecological pond 16 is connected with the water outlet of the membrane bioreactor 13 through a pipeline, the ecological pond 16 is provided with a filter membrane layer 17 and an aquatic plant area 18, the filter membrane layer 17 is located below the aquatic plant area 18, and the water inlet of the ecological pond 16 is located above the aquatic plant area 18. The aquaculture tail water after microbial degradation enters the ecological pond 16, the pollutants in the aquaculture tail water are degraded by the aquatic plants and the root bacterial flora of the aquatic plant area 18, and then the phosphorus is adsorbed by the filter membrane layer 17 below to ensure that the phosphorus content of the effluent meets the requirements of recycling.

[0063] The thickness of the filter membrane layer 17 is 10-20 cm, the filter membrane layer 17 is stacked by a plurality of iron-based MOF composite filter membranes, the iron-based MOF composite filter membrane has good adsorption performance on phosphate in water, and the iron-based MOF material will not be lost with water and has good stability.

[0064] Specifically, the water outlet of the ecological pond 16 is connected with the water inlet of the ozone oxidation reactor 6 through a reflux pipeline and a reflux pump (not shown in the figure), and the water outlet of the ecological pond 16 is connected with a water outlet pipe. The water discharged through the water outlet pipe enters the circulating channel and then enters the aquaculture pond 19 through the circulating channel.

[0065] Valves are arranged on each pipeline in the embodiment, and the opening degree of the valves can be adjusted to adjust the flow rate of the fluid.

[0066] Embodiment 2

[0067] The embodiment provides a high-efficiency phosphorus removal method for aquaculture tail water, and the system is implemented by a high-efficiency phosphorus removal system for aquaculture tail water. The difference between the system and the high-efficiency phosphorus removal system for aquaculture tail water provided in embodiment 1 lies in that in the embodiment, the spacing between any two adjacent baffles 8 is 40 cm, the number of the baffles 8 is 4, the thickness of the bacteria-algae filler layer 14 is 120 cm, the thickness of the filter membrane layer 17 is 15 cm, and the mass percentage of the iron-based MOF material in the iron-based MOF composite filter membrane is 3%.

[0068] In the preparation method of the bacteria-algae filler in the embodiment, the weight ratio of sawdust, coconut shell and coal powder in the biochar carrier is sawdust: coconut shell: coal powder = 2:3:10, the bacillus powder comes from the bacillus agent (Bacillus subtilis) of Shandong Zhongke Jiayu Company, the photosynthetic bacterial concentrate comes from the photosynthetic bacteria (liquid marshy red pseudomonas) of Henan Nanhua Qianmu Company, the algal liquid comes from the algal liquid (Chlorella pyrenoidosa) of Xi'an Zebang Company, the ratio between the weight of the bacillus powder and the volume of the bacteria-algae mixed suspension is 10 g / L, the volume ratio between the photosynthetic bacterial concentrate and the bacteria-algae mixed suspension is 0.01, the volume ratio between the algal liquid and the bacteria-algae mixed suspension is 0.02, and the volume ratio between the biochar carrier and the bacteria-algae mixed suspension is 3 g:200 mL.

[0069] After high-pressure sterilization of the biochar carrier, the mixed suspension of bacteria and algae is added, the pH value is adjusted to 6.8-7.2, and the constant temperature oscillation culture is carried out at 30°C and 150r / min for 24h. After standing, filtration is carried out, and the immobilized body is obtained by washing with sterile saline for 3 times.

[0070] The obtained immobilized body is added into a 2% sodium alginate solution, the ratio between the mass of the immobilized body and the volume of the sodium alginate solution is 1g:20mL, and then the mixture is uniformly mixed and loaded into a syringe. The syringe is dropped into a 5% calcium chloride solution, the molar ratio of sodium alginate to calcium chloride is 1:2, and after the dropping is completed, the crosslinking is carried out for 5h. After washing and filtering with sterile water, the bacteria and algae filler is obtained.

[0071] The method for efficiently removing phosphorus from the aquaculture tail water comprises the following steps:

[0072] S1, the aquaculture tail water is input into a filter tank 2, filtered through a grid 3, and then input into a pretreatment tank 1;

[0073] S2, the tail water treated in step S1 is input into a sedimentation tank 5 by using a lifting pump 4, and then allowed to stand and deposit;

[0074] S3, the tail water treated in step S2 is input into an ozone oxidation reactor 6, a catalyst is added into the ozone oxidation reactor 6 by using a catalyst adding device 8, and ozone is input into the ozone oxidation reactor 6 by using an ozone generator 9, so that the tail water is subjected to ozone oxidation treatment;

[0075] S4, the tail water treated in step S3 is input into a carbon source supplement tank 10, and a carbon source is added into the carbon source supplement tank 10 by using a carbon source adding device 12;

[0076] S5, the tail water treated in step S4 is input into a membrane bioreactor 13 for microbial degradation treatment, and at the same time, subjected to aeration treatment;

[0077] S6, the tail water treated in step S5 is input into an ecological pond for adsorption degradation treatment;

[0078] S7, the content of phosphorus element in the tail water treated in step S6 is detected; when the content of phosphorus element does not reach the standard, the tail water treated in step S6 is input into the ozone oxidation reactor, the reflux ratio is 1:1, and steps S3-S6 are continuously carried out; when the content of phosphorus element reaches the standard, the tail water treated in step S6 is discharged into the aquaculture pond.

[0079] In step S3, the hydraulic retention time of the ozone oxidation reactor is 20min, the ratio between the amount of the catalyst and the volume of the tail water is 0.5g / L, and the flow rate of the ozone is 0.5g / L;

[0080] In step S4, the carbon source is supplemented to the tail water to make the carbon-nitrogen ratio (4-6):1.

[0081] In step S5, the aeration amount is 10 m 3 / h during the aeration treatment.

[0082] Example 3

[0083] The present example provides a method for efficiently removing phosphorus from aquaculture tail water. The difference between the present example and example 2 is that, in the preparation method of the bacteria-algae filler, the ratio between the weight of the bacillus powder and the volume of the bacteria-algae mixed suspension is 5 g / L, the volume ratio between the photosynthetic bacterial concentrate and the bacteria-algae mixed suspension is 0.005, and the volume ratio between the algal liquid and the bacteria-algae mixed suspension is 0.01.

[0084] Example 4

[0085] The present example provides a method for efficiently removing phosphorus from aquaculture tail water. The difference between the present example and example 2 is that, in the present example, the ratio between the weight of the bacillus powder and the volume of the bacteria-algae mixed suspension is 15 g / L, the volume ratio between the photosynthetic bacterial concentrate and the bacteria-algae mixed suspension is 0.015, and the volume ratio between the algal liquid and the bacteria-algae mixed suspension is 0.03.

[0086] Example 5

[0087] The present example provides a method for efficiently removing phosphorus from aquaculture tail water. The difference between the present example and example 2 is that, in the present example, the weight ratio of sawdust, coconut shell, and coal powder is sawdust: coconut shell: coal powder = 1:5:10, the mass of the biochar carrier to the volume of the bacteria-algae mixed suspension is 1 g:200 mL; and the mass percentage of the iron-based MOF material in the iron-based MOF composite filter membrane is 1%.

[0088] Example 6

[0089] The present example provides a method for efficiently removing phosphorus from aquaculture tail water. The difference between the present example and example 2 is that, in the present example, the weight ratio of sawdust, coconut shell, and coal powder is sawdust: coconut shell: coal powder = 3:2:10, the mass of the biochar carrier to the volume of the bacteria-algae mixed suspension is 5 g:200 mL; and the mass percentage of the iron-based MOF material in the iron-based MOF composite filter membrane is 10%.

[0090] Example 7

[0091] The embodiment provides a high-efficiency phosphorus removal method for aquaculture tail water, and the difference between the embodiment and the embodiment 2 is that, in the embodiment, in step S3, the hydraulic retention time of the ozone oxidation reactor is 15 min, the ratio between the input amount of the catalyst and the volume of the tail water is 1.0 g / L, and the flow rate of the ozone is 1.0 g / L; in step S5, the aeration amount is 5 m 3 / h when the aeration treatment is performed.

[0092] Embodiment 8

[0093] The embodiment provides a high-efficiency phosphorus removal method for aquaculture tail water, and the difference between the embodiment and the embodiment 2 is that, in the embodiment, in step S3, the hydraulic retention time of the ozone oxidation reactor is 30 min, the ratio between the input amount of the catalyst and the volume of the tail water is 0.5 g / L, and the flow rate of the ozone is 1.0 g / L; in step S5, the aeration amount is 20 m 3 / h when the aeration treatment is performed.

[0094] Comparative example 1

[0095] The comparative example provides a phosphorus removal method for aquaculture tail water, and the difference between the comparative example and the embodiment 2 is that, in the comparative example, the photosynthetic bacteria are not used, and in the comparative example, the ratio between the weight of the bacillus powder and the volume of the bacterium-algae mixed suspension is 20 g / L.

[0096] Comparative example 2

[0097] The comparative example provides a phosphorus removal method for aquaculture tail water, and the difference between the comparative example and the embodiment 2 is that, in the comparative example, the chlorella liquid is not used, and the comparative example uses a commercially available navicula liquid.

[0098] Comparative example 3

[0099] The comparative example provides a phosphorus removal method for aquaculture tail water, and the difference between the comparative example and the embodiment 2 is that, in the comparative example, the composite filter membrane does not contain the iron-based MOF material, and the comparative example uses an equal amount of activated carbon to replace the iron-based MOF material in the embodiment 2.

[0100] Effect example 1

[0101] The same cultivation tail water is treated according to the methods in the embodiments 2-8 and the comparative examples 1-2, the COD content, the ammonia nitrogen content and the total phosphorus content in the cultivation tail water are detected before the treatment, the COD content, the ammonia nitrogen content and the total phosphorus content in the effluent of the ecological pond are detected after single-pass treatment, and the COD removal rate, the ammonia nitrogen removal rate and the total phosphorus removal rate are calculated, and the results are shown in the following table 1.

[0102] Table 1

[0103]

[0104] As can be seen from Table 1, compared with single bacteria, the photosynthetic bacteria and bacillus complex used in the application can better degrade organic matter in water; compared with boji algae, the chlorella loaded in the bacteria-algae filler layer 14 of the application has a wider temperature range, higher enzyme activity and better metabolism, so that it has a better effect on the degradation of organic matter through its own metabolism; compared with the filter membrane containing activated carbon, the iron-based MOF filter membrane used in the application has a larger adsorption capacity and a better adsorption effect on phosphorus.

[0105] It should be understood that, in the description of the application, the orientation or positional relationship indicated by the terms "upper", "lower" and the like is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0106] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present application and are not a limitation on the protection scope of the present application. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present application.

Claims

1. An efficient phosphorus removal system for aquaculture effluent, characterized by, The system comprises, in sequence, a pretreatment device, a sedimentation tank, an ozone oxidation device, a carbon source supplementing device, a membrane biological reaction device, and an ecological pond; the ozone oxidation device comprises an ozone oxidation reactor, a catalyst feeding device, and an ozone generator, the top of the ozone oxidation reactor is provided with a catalyst inlet and an ozone inlet, the catalyst feeding device is internally provided with catalysts, the outlet of the catalyst feeding device is connected with the catalyst inlet through a pipeline, and the ozone output end of the ozone generator is connected with the ozone inlet through a pipeline; the carbon source supplementing device comprises a carbon source supplementing tank, a stirrer, and a carbon source feeding device, the carbon source feeding device is used for feeding carbon sources into the carbon source supplementing tank; the membrane biological reaction device comprises a membrane biological reactor, the membrane biological reactor is internally provided with a bacteria-algae filler layer and a micro-nano bubble generator, and the micro-nano bubble generator is located below the bacteria-algae filler layer; The bacteria-algae filler layer comprises a carrier, the carrier is loaded with probiotics and algae, and the algae comprise at least one of chlorella and cryptomonads; The water inlet of the ecological pond is connected with the water outlet of the membrane biological reactor through a pipeline, the ecological pond is internally provided with a filter membrane layer and an aquatic plant area, the filter membrane layer is located below the aquatic plant area, and the water inlet of the ecological pond is located below the aquatic plant area; the filter membrane layer is stacked by a plurality of iron-based MOF composite filter membranes, and the mass percentage of the iron-based MOF material in the iron-based MOF composite filter membrane is 1-10%.

2. The recirculating aquaculture high rate phosphorus removal system of claim 1, wherein, The ozone oxidation reactor is internally provided with at least three staggered baffles, and the baffles divide the internal space of the ozone oxidation reactor into a zigzag flow channel.

3. The recirculating aquaculture high rate phosphorus removal system of claim 1, wherein, The probiotics comprise at least one of bacillus and photosynthetic bacteria.

4. The recirculating aquaculture high rate phosphorus removal system of claim 1, wherein, The water outlet of the ecological pond is connected with the water inlet of the ozone oxidation reactor through a reflux pipeline and a water pump.

5. A method for efficient phosphorus removal from aquaculture effluent, characterized by, The system is implemented by the water production breeding tail water efficient phosphorus removal system as claimed in any one of claims 1-4.

6. The method of efficient phosphorus removal from aquaculture effluent according to claim 5, wherein, The system comprises the following steps: S1, inputting breeding tail water into a pretreatment device for pretreatment; S2, inputting the tail water treated in step S1 into a sedimentation tank for sedimentation treatment; S3, inputting the tail water treated in step S2 into an ozone oxidation reactor, feeding catalysts, and inputting ozone to perform ozone oxidation treatment on the tail water entering the ozone oxidation reactor; S4, inputting the tail water treated in step S3 into a carbon source supplementing tank, supplementing carbon sources, and stirring; S5, inputting the tail water treated in step S4 into a membrane biological reactor for microbial degradation treatment, and simultaneously performing aeration treatment; S6, inputting the tail water treated in step S5 into an ecological pond for adsorption degradation treatment.

7. The method of efficient phosphorus removal from aquaculture effluent according to claim 5, wherein, In step S3, the hydraulic retention time of the ozone oxidation reactor is 15-30 min, the ratio between the amount of catalysts and the volume of the tail water is 0.5-1.0 g / L, and the flow rate of the ozone is 0.5-1.0 g / L.

8. The method of efficient phosphorus removal from aquaculture effluent of claim 5, wherein, In step S5, the aeration amount during the aeration treatment is 5 to 20 m 3 / h.

9. The method of efficient phosphorus removal from aquaculture effluent of claim 5, wherein, After step S6, the tail water treated in step S6 is further refluxed into the ozone oxidation reactor, and the reflux ratio is (1-2):1.

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