CN115611445A

CN115611445A - Harmless treatment system and process for eutrophic aquaculture wastewater

Info

Publication number: CN115611445A
Application number: CN202110733203.1A
Authority: CN
Inventors: 郭鹏飞; 曾建新; 陈海峰
Original assignee: Wuxi Jinpeng Environmental Protection Technology Co ltd
Current assignee: Wuxi Jinpeng Environmental Protection Technology Co ltd
Priority date: 2021-06-30
Filing date: 2021-06-30
Publication date: 2023-01-17
Anticipated expiration: 2041-06-30
Also published as: CN115611445B

Abstract

The invention discloses a harmless treatment system and a process for eutrophic aquaculture wastewater, wherein the system comprises a sedimentation tank, a filter, an adjusting tank, a mixing reactor and a reaction tank which are sequentially connected; the mixing reactor comprises a mixing tank, a circulating pump, an air self-suction device connected with the circulating pump, an ozone self-suction device connected with the circulating pump and an ozone generator connected with the ozone self-suction device. According to the invention, the mixing of ozone and the water body is enhanced through the mixing reactor, so that the gas forms tiny bubbles to fully collide and contact with the water body, the ozone treatment effect can be improved, and the ozone consumption is reduced; meanwhile, the content of dissolved oxygen in the water body can be improved; the invention can filter suspended particles and simultaneously remove a large amount of nitrogen and phosphorus pollutants with high content by a multi-filter layer structure aiming at the characteristics of eutrophic aquaculture wastewater, thereby playing a role in pretreatment for subsequent purification.

Description

Harmless treatment system and process for eutrophic aquaculture wastewater

Technical Field

The invention relates to the technical field of wastewater treatment, in particular to a system and a process for harmlessly treating eutrophic aquaculture wastewater.

Background

The main pollutants in the aquaculture wastewater include ammonia nitrogen, nitrite, organic pollutants, phosphorus and fouling organisms. At present, the investigation and research on the fouling organisms in certain estuaries and traditional cage culture areas are developed in China. Unlike industrial and domestic sewage, aquatic fish sewage is low concentration organic sewage with simple pollutant components, and BOD is generally not more than 80mg/L. But the aquatic organisms have higher requirements on water quality, ammonia nitrogen and hydrogen sulfide are the most common harmful substances in the seedling raising water body, and the concentrations of the ammonia nitrogen and the hydrogen sulfide in the water body can be gradually increased along with the progress of seedling raising. The ammonia nitrogen is the excrement of aquatic organisms and is the end product of the decomposition of nitrogenous organic matters such as residual feed, excrement, animal and plant corpses and the like. The hydrogen sulfide is formed by the decomposition of sulfur-containing organic matters by anaerobic bacteria under the anoxic condition. The disease is caused by mass propagation of pathogenic bacteria such as vibrio caused by deterioration of water quality and substrate, and the disease is more easily infected by the disease resistance of aquatic organisms which is caused by the comprehensive factor of ecological imbalance caused by the destruction of an ecological system and the increase of stocking density.

Therefore, aquaculture wastewater can be discharged after being purified, and a plurality of treatment methods for aquaculture wastewater, including physical and chemical treatment methods, biofilm methods, salt-tolerant plant treatment methods, artificial wetland treatment methods, comprehensive treatment methods of precipitation, shellfish filtration and algae adsorption, and the like, have been developed at home and abroad.

However, many existing treatment processes have the defects of poor purification effect, incapability of meeting the requirement of emission standards, low content of dissolved oxygen in effluent and the like, so a more reliable scheme is required at present.

Disclosure of Invention

The invention aims to solve the technical problem of providing a system and a process for harmless treatment of eutrophic aquaculture wastewater aiming at the defects in the prior art.

In order to solve the technical problems, the invention adopts the technical scheme that: a harmless treatment system for eutrophic aquaculture wastewater comprises a sedimentation tank, a filter, an adjusting tank, a mixing reactor and a reaction tank which are connected in sequence;

the mixing reactor comprises a mixing tank, a circulating pump, an air self-priming device connected with the circulating pump, an ozone self-priming device connected with the circulating pump and an ozone generator connected with the ozone self-priming device;

the upper part and the bottom of the mixing tank are respectively provided with a water inlet pipe and a water outlet pipe, and the lower part of the mixing tank, which is positioned above the water outlet pipe, is also provided with a circulating water outlet communicated with the inlet end of the circulating pump;

the air self-suction device and the ozone self-suction device have the same structure and respectively comprise a feeding pipe section connected with the outlet end of the circulating pump, a jet pipe section communicated with the feeding pipe section and a discharge pipe section, wherein one end of the discharge pipe section is communicated with the jet pipe section, and the other end of the discharge pipe section is communicated with the mixing tank; the jet pipe section comprises an air suction chamber, a nozzle inserted in the inlet end of the air suction chamber and an air suction pipe communicated with the air suction chamber, the inlet end of the nozzle is communicated with the feeding pipe section, the outlet end of the air suction chamber is communicated with the discharging pipe section, water output by the circulating pump sequentially passes through the feeding pipe section, the jet pipe section, the air suction chamber and the discharging pipe section and then enters the mixing tank, and in the process, the air suction pipe sucks external gas into the air suction chamber.

Preferably, the suction pipe is arranged to be inclined toward the direction of the feed pipe section.

Preferably, the feeding pipe section and the nozzle are in transitional connection through a first conical pipe, the outlet end of the air suction chamber is in transitional connection with a throat pipe with the diameter smaller than that of the discharge pipe section through a second conical pipe, the diameter of the throat pipe is smaller than that of the outlet end of the air suction chamber, and the throat pipe is in transitional connection with the discharge pipe section through a third conical pipe;

the outlet of the nozzle is opposite to the second cone pipe.

Preferably, the mixing tank is cylindrical, and the water inlet pipe is connected with the mixing tank along the tangential direction; the air self-suction device and the ozone self-suction device are characterized in that discharge pipe sections of the air self-suction device and the ozone self-suction device are connected with the mixing tank along the tangential direction, and the connection positions of the discharge pipe sections and the mixing tank are located between the circulating water outlet and the water inlet pipe.

Preferably, the output end of the ozone generator is further connected with a gas buffer tank, and an air suction pipe of the ozone self-suction device is communicated with the gas buffer tank.

Preferably, the filter comprises a filter tank, and a buffer filter layer, a first filter layer, a second filter layer and a third filter layer which are sequentially arranged in the filter tank at intervals along the vertical direction;

the buffer filter layer and the first filter layer, the first filter layer and the second filter layer, and the second filter layer and the third filter layer are separated by the wave-shaped filter plate.

Preferably, the top and the bottom of the filter tank are respectively provided with a wastewater inlet and a wastewater outlet;

be provided with a plurality of and along the vertical direction between waste water entry and the buffering filtering layer filter tank's inner wall connection's slope buffer board, and a plurality of slope buffer boards crisscross the setting.

Preferably, the filler of the buffer filter layer is: cobblestones with a diameter between 5 and 15 mm;

the filler of the first filter layer is: coal gangue with the diameter of 2-6 mm;

the filler of the second filter layer is: a mixture of calcite and dolomite, wherein the diameters of the calcite and the dolomite are both 0.5-3mm;

the filler of the third filter layer is: a mixture of ferromanganese ore particles and powdered coke particles, and the diameter of each of the ferromanganese ore particles and the powdered coke particles is 0.1 to 1mm.

Preferably, the treatment process of the eutrophic aquaculture wastewater harmless treatment system comprises the following steps:

1) Conveying the culture wastewater discharged from the culture pond to the sedimentation pond, adding a coagulant into the sedimentation pond, and settling for 2-6 hours;

2) Conveying the overflow of the sedimentation tank into the filter by a water pump for filtering;

3) Automatically flowing water discharged by the filter to the regulating tank through a pipeline;

4) The effluent of the regulating reservoir is conveyed into the mixing reactor through a water pump, so that the water is fully mixed with air and ozone;

5) Water discharged by the mixing reactor automatically flows to the reaction tank through a pipeline for treatment;

6) And delivering the treated effluent in the reaction tank to the culture tank for cyclic utilization through a water pump.

Preferably, the coagulant is polyaluminium chloride.

The invention has the beneficial effects that:

according to the harmless treatment system for eutrophic aquaculture wastewater, the mixing of ozone and the water body is enhanced through the mixing reactor, so that gas forms tiny bubbles to fully collide and contact with the water body, the treatment effect of ozone can be improved, and the using amount of ozone is reduced, thereby overcoming the defect of high cost caused by large ozone demand in the conventional ozone treatment method; meanwhile, the mixing reactor can also enhance the dissolving efficiency of oxygen in the air in water and improve the content of dissolved oxygen in water;

aiming at the characteristics of eutrophic aquaculture wastewater, the multi-filter-layer structure can filter suspended particles and simultaneously remove a large amount of nitrogen and phosphorus pollutants with high content, thereby playing a role in pretreatment for subsequent purification;

the aquaculture wastewater treated by the system can reach the requirement of the emission standard, and the dissolved oxygen is greatly increased, so that the effluent can be conveyed to the aquaculture pond again for recycling, and a large amount of water resources can be saved.

Drawings

FIG. 1 is a schematic structural view of a system for the harmless treatment of eutrophic aquaculture wastewater in accordance with the present invention;

FIG. 2 is a schematic view of the structure of a mixing reactor according to the present invention;

FIG. 3 is a schematic structural diagram of the ozone self-priming device of the present invention;

FIG. 4 is a schematic top view of a discharge tube section of the present invention in combination with a mixing tank;

fig. 5 is a schematic view of the filter of the present invention.

Description of reference numerals:

1-a culture pond;

2-a sedimentation tank;

3, a filter; 30-a filter tank; 31-buffer filter layer; 32 — a first filter layer; 33-a second filter layer; 34-a third filter layer; 35-wave type filter plate; 36-inclined buffer plate; 37-wastewater inlet; 38-waste water outlet;

4, a regulating tank;

5-a mixing reactor;

50-mixing tank; 51-a circulation pump; 52-air self-suction device; 53-ozone self-priming device; 54-an ozone generator; 55-gas buffer tank; 56-a feed pipe section; 57-jet section; 58-a discharge pipe section; 500-water inlet pipe; 501, a drain pipe; 502-circulating water outlet; 570-a suction chamber; 571, a nozzle; 572-suction duct; 573-throat pipe; 574 — a first cone tube; 575-a second cone; 576-a third cone;

6-reaction tank.

Detailed Description

The present invention is further described in detail below with reference to examples so that those skilled in the art can practice the invention with reference to the description.

It will be understood that terms such as "having," "including," and "comprising," as used herein, do not preclude the presence or addition of one or more other elements or groups thereof.

Example 1

As shown in fig. 1-4, the system for harmless treatment of eutrophic aquaculture wastewater of this embodiment comprises a sedimentation tank 2, a filter 3, a regulating tank 4, a mixing reactor 5 and a reaction tank 6, which are connected in sequence;

the mixing reactor 5 comprises a mixing tank 50, a circulating pump 51, an air self-priming device 52 connected with the circulating pump 51, an ozone self-priming device 53 connected with the circulating pump 51 and an ozone generator 54 connected with the ozone self-priming device 53;

the upper part and the bottom of the mixing tank 50 are respectively provided with a water inlet pipe 500 and a water outlet pipe 501, and the lower part of the mixing tank 50, which is positioned above the water outlet pipe 501, is also provided with a circulating water outlet 502 communicated with the inlet end of the circulating pump 51;

the air self-priming device 52 and the ozone self-priming device 53 have the same structure, and referring to fig. 3, the ozone self-priming device 53 is taken as an example, and comprises a feeding pipe section 56 connected with the outlet end of the circulating pump 51, a jet pipe section 57 communicated with the feeding pipe section 56, and a discharge pipe section 58 with one end communicated with the suction pipe 572 section and the other end communicated with the mixing tank 50; the jet pipe section 57 comprises a suction chamber 570, a nozzle 571 inserted in the inlet end of the suction chamber 570, and a suction pipe 572 communicated with the suction chamber 570, the inlet end of the nozzle 571 is communicated with the feed pipe section 56, the outlet end of the suction chamber 570 is communicated with the discharge pipe section 58, water output by the circulating pump 51 sequentially passes through the feed pipe section 56, the jet pipe section 57, the suction chamber 570, and the discharge pipe section 58 and then enters the mixing tank 50, and in the process, the suction pipe 572 sucks external gas into the suction chamber 570.

According to the invention, part of the wastewater in the mixing tank 50 is pumped out by the circulating pump 51, negative pressure is formed by the jet action of the nozzle 571 in the air suction chamber 570, so that external air and ozone are automatically sucked, and the wastewater enter the mixing tank 50 together, so that the wastewater is fully mixed with the air and the ozone, on one hand, dissolved oxygen in a water body is increased, on the other hand, the wastewater is treated by the strong oxidation of the ozone through full contact of the ozone and the wastewater, COD (chemical oxygen demand) of the water body is reduced, ammonia nitrogen and nitrite in the water body are reduced, pathogenic bacteria in the water body are killed, and the purpose of purifying the water quality is achieved. The ozone can destroy and decompose cell walls of cells to kill pathogenic bacteria, and intermediate substance hydroxyl radical (-OH) decomposed by the ozone in water has strong oxidizing property and can decompose organic matters, and in addition, the ozone can also increase dissolved oxygen in water. In the invention, the mixing reactor 5 is used for fully mixing the ozone and the water body, thereby not only improving the treatment efficiency of the ozone, but also reducing the using amount of the ozone; and meanwhile, the dissolving efficiency of oxygen in the air in water can be enhanced, and the dissolved oxygen content in the water body can be improved. The dissolved oxygen content is an important factor influencing the nitrification rate of the nitrifying bacteria, and the oxygen content of the water body can be improved, so that the nitrification rate can be improved. The conventional ozone treatment method needs to introduce a large amount of ozone, so that the cost is high, but the mixing of the ozone and the water body is enhanced through the mixing reactor 5, so that the gas forms tiny bubbles to be in full collision contact with the water body, the ozone treatment effect can be improved, and the using amount of the ozone is reduced.

In this embodiment, the suction pipe 572 is inclined toward the direction of the feed pipe section 56, and the liquid discharged from the nozzles 571 can be prevented from leaking from the suction pipe 572.

In this embodiment, the feeding pipe segment 56 and the nozzle 571 are connected by a first taper pipe 574, the outlet end of the suction chamber 570 is connected by a second taper pipe 575 with a throat 573 having a smaller diameter than the discharge pipe segment 58, the diameter of the throat 573 is smaller than the diameter of the outlet end of the suction chamber 570, and the throat 573 is connected by a third taper pipe 576 with the discharge pipe segment 58; the outlet of the nozzle 571 faces the second taper pipe 575.

Wherein, the feeding pipe section 56 is connected with the nozzle 571 through the first cone, the pipe diameter is reduced, the speed of water discharged from the feeding pipe section 56 is increased, a higher-speed jet flow is formed, and the self-priming effect can be enhanced; the outlet end of the suction chamber 570 is connected with the throat 573 through a second taper pipe 575, and can guide the water sprayed from the nozzle 571 and the gas entering the suction chamber 570 to jointly enter the throat 573; the throat 573 is in transitional connection with the discharge pipe section 58 through a third cone 576, and the pipe diameter is increased, so that the self-absorption effect of the rear suction chamber 570 can be enhanced when water is sprayed into the discharge pipe section 58 from the throat 573; the suction chamber 570 can suck a sufficient amount of gas by the above-described structure.

In this embodiment, the mixing tank 50 is cylindrical, and the water inlet pipe 500 is connected to the mixing tank 50 along the tangential direction; the discharge pipe section 58 of the air self-priming device 52 and the ozone self-priming device 53 are connected with the mixing tank 50 in a tangential direction, and the connection position of the discharge pipe section 58 and the mixing tank 50 is between the circulating water outlet 502 and the water inlet pipe 500. The inlet tube 500 and the discharge tube section 58 all carry water to the blending tank 50 along tangential direction to the time water forms the whirl in the blending tank 50 (wherein, the arrangement of inlet tube 500 and two discharge tube sections 58 need make the direction of its whirl effect that produces respectively the same, as figure 4), and the effect of whirl makes gaseous and the more abundant collision contact of water, thereby can improve the treatment effect of ozone and the promotion effect of water dissolved oxygen.

The working principle of the mixing reactor 5 is as follows:

the wastewater is injected into the mixing tank 50 from the water inlet pipe 500 at a high speed along the tangential direction, flows downwards in a rotating mode under the action of gravity and rotational flow, is fully mixed with air and ozone, and is discharged from a drain pipe 501 at the bottom;

the circulating pump 51 pumps out part of the waste water mixed with ozone and air from the bottom of the mixing tank 50 (above the drain pipe 501) (at the same time, the circulating pump 51 further promotes the mixing of the water and the air), and then the waste water is sprayed out of the nozzle 571 into the suction chamber 570 at a high speed, the nozzle 571 faces the outlet end of the suction chamber 570 and is close to the outlet end of the suction chamber 570, and the waste water continues to enter the discharge pipe section 58 from the outlet end of the suction chamber 570 at a high speed and then is sprayed into the mixing tank 50 tangentially. The wastewater in the nozzle 571 is jetted out in a jet flow manner, so that the suction chamber 570 generates negative pressure, external gas (air and ozone) is sucked in through the suction pipe 572, and the sucked gas is crushed into bubbles under the shearing action of the jet flow, so that the water body is fully contacted; gas and water are sprayed into mixing tank 50 along the tangent line after, can strengthen the whirl effect in the mixing tank 50, and the bubble upward movement under the buoyancy further collides with rotatory downstream's water for adsorb a large amount of microbubbles on the water, the purification effect of improvement ozone to the water and the dissolving effect of the oxygen in the air in the water that can be very big.

In the embodiment, air is introduced while ozone is introduced, so that dissolved oxygen of the water body can be further increased, and the effect of the rotational flow can be improved.

In this embodiment, the output end of the ozone generator 54 is further connected to a gas buffer tank 55, and the air suction pipe 572 of the ozone self-priming device 53 is communicated with the gas buffer tank 55. Ozone generated by the ozone generator 54 is buffered in the gas buffer tank 55, and then enters the mixing tank 50 under the self-priming action of the ozone self-priming device 53.

Example 2

Referring to fig. 5, as a further improvement on embodiment 1, in this embodiment, the filter 3 includes a filter tank 30, a buffer filter layer 31, a first filter layer 32, a second filter layer 33, and a third filter layer 34, which are sequentially disposed in the filter tank 30 at intervals in the vertical direction;

the wave-type filter sheet 35 separates the space between the buffer filter layer 31 and the first filter layer 32, the space between the first filter layer 32 and the second filter layer 33, and the space between the second filter layer 33 and the third filter layer 34.

In this embodiment, the top and the bottom of the filter tank 30 are respectively provided with a waste water inlet 37 and a waste water outlet 38; a plurality of inclined buffer plates 36 connected with the inner wall of the filtering tank 30 are arranged between the wastewater inlet 37 and the buffer filtering layer 31 along the vertical direction, and the inclined buffer plates 36 are arranged in a staggered manner. The inclined buffer plate 36 has a buffer effect on the entering wastewater, and prevents the wastewater from directly impacting the buffer filter layer 31 to cause the reduction of the service life of the filler of the buffer filter layer 31 due to erosion; on the other hand, the crisscross setting of polylith slope buffer board 36 also can make the more even surface that flows into buffering filtering layer 31 of waste water, can improve the filtration efficiency of follow-up a plurality of filtering layers.

In this embodiment, the filler of the buffer filter layer 31 is: cobblestones with a diameter between 5 and 15 mm; the filler for the first filter layer 32 is: coal gangue with the diameter of 2-6 mm;

the filler of the second filter layer 33 is: a mixture of calcite and dolomite, wherein the diameters of the calcite and the dolomite are both 0.5-3mm; eutrophic aquaculture wastewater contains a large amount of phosphorus, calcite and dolomite contain a large amount of calcium ions, and the calcium ions can effectively precipitate the phosphorus from an aqueous solution, so that the content of the phosphorus is greatly reduced.

The filler of the third filter layer 34 is: a mixture of ferromanganese ore particles and powdered coke particles, and the diameter of each of the ferromanganese ore particles and the powdered coke particles is 0.1 to 1mm. The filter bed packing needs to have both a high porosity and sufficient mechanical strength to extend its useful life. The ferromanganese ore particles have higher strength, iron in the ferromanganese ore particles has a remarkable effect of reducing the content of phosphorus, the powdery coke particles have high porosity and can ensure the pollutant energy of the filter layer, and the ferromanganese ore particles and the powdery coke particles are mixed as filler of the filter layer, so that the ferromanganese ore particles and the powdery coke particles have the effects of strengthening adsorption and purifying water quality.

The aquaculture wastewater contains a large amount of suspended particles such as suspended matters, excrement, bait residues and the like, and in order to ensure the normal operation of a subsequent wastewater treatment system, the filter tank 30 can be used for removing the large amount of suspended particles in the wastewater; in the embodiment, by the multi-filter-layer structure, aiming at the characteristics of eutrophic aquaculture wastewater, suspended particles can be filtered, and meanwhile, a large amount of nitrogen and phosphorus pollutants with high content can be removed, so that the effect of pretreatment is achieved for subsequent purification.

Example 3

The present embodiment also provides a treatment process of the eutrophic aquaculture wastewater harmless treatment system of embodiment 2, which comprises the following steps:

1) Conveying the culture wastewater discharged from the culture pond 1 to a sedimentation pond 2, adding a coagulant into the sedimentation pond 2, and settling for 2-6 hours; in the embodiment, the precipitation is carried out for about 4 hours, and the coagulant is polyaluminium chloride;

2) The overflow of the sedimentation tank 2 is conveyed to a middle filter 3 by a water pump for filtration;

3) The water discharged by the filter 3 automatically flows to the adjusting tank 4 through a pipeline;

4) The effluent of the regulating reservoir 4 is conveyed into a mixing reactor 5 through a water pump, so that the water is fully mixed with air and ozone;

5) Water discharged from the mixing reactor 5 automatically flows to the reaction tank 6 through a pipeline for treatment;

6) The treated effluent in the reaction tank 6 is conveyed to the culture tank 1 by a water pump for cyclic utilization.

In the embodiment, the treatment process is adopted to treat the waste water of the freshwater aquaculture fishpond, and relevant indexes are detected.

The aquatic product cultured in the pond mainly comprises grass carp, crucian carp, silver carp, eel, male fish and the like; the main indexes of the discharged wastewater are shown in the following table 1:

TABLE 1

The indexes of effluent treated by the process of example 3 are shown in the following table 2:

TABLE 2

According to the requirements for the discharge of culture water in fresh water ponds (SC/T9101-2007), the primary standard is shown in Table 3:

TABLE 3

In this example, a comparative experiment was also performed, in which the mixing reactor 5 was not included, ozone was directly introduced into the reaction tank 6 to treat the water, the other conditions were the same as in example 4, and the effluent of the comparative experiment was detected with the detection indexes shown in table 4.

TABLE 4

As can be seen from the results in tables 1, 2 and 3, the wastewater treatment process of the embodiment can greatly reduce pollutants in aquaculture wastewater, plays a good role in water purification, and the discharged effluent can meet the requirements of relevant standards. In addition, as can be seen from the comparison between table 1 and table 2, the content of dissolved oxygen in the effluent is greatly increased, which is significantly higher than the standard requirement. In the invention, in order to fully utilize water resources, the treated effluent is conveyed to the culture pond 1 again for recycling, and aquatic organisms have higher requirements on the content of dissolved oxygen in the water body, the higher the dissolved oxygen is, the better the dissolved oxygen is, in a certain range, generally, the higher the dissolved oxygen is, the lower the bait coefficient is (indicating that the bait can be effectively utilized), the stronger the appetite of the fish is, and the faster the growth speed is. For example, in general, the feed factor of fish at dissolved oxygen of 3mg/L is doubled compared to that at 4mg/L, and fish growing at 7mg/L will grow 20% to 30% faster than fish growing at 4mg/L, whereas the feed factor is 30% to 50% lower. In the current aquaculture process, the dissolved oxygen level in water often cannot meet the requirement, and the feed reward is influenced. Therefore, in order to ensure that the aquatic animals can utilize the fed feed to the best limit and achieve the purpose of full growth, the dissolved oxygen in the water should be not less than 5mg/L-7mg/L. In the embodiment, the recycled effluent has the dissolved oxygen content of 7.4mg/L, and can well meet the requirement of aquatic animals on dissolved oxygen.

As can be seen from the comparison of the results in tables 2 and 4, when ozone is directly introduced into the reaction tank 6 to treat the water without using the mixing reactor 5, the content of organic pollutants in the obtained effluent is remarkably increased, the water purification effect is remarkably reduced, and even the requirement of the emission index can not be met. This is because in this embodiment, through closing the mixing of reactor can very big intensive ozone, air and water, and make gas form the microbubble and fully collide the contact with the water, both showing the purifying effect of ozone to the water, also strengthened the dissolution efficiency of the oxygen in the air in aqueous simultaneously to finally can strengthen the purifying effect of whole technology to the water, and can improve the dissolved oxygen in the water greatly.

While embodiments of the invention have been disclosed above, it is not limited to the applications listed in the description and the embodiments, which are fully applicable in all kinds of fields of application of the invention, and further modifications may readily be effected by those skilled in the art, so that the invention is not limited to the specific details without departing from the general concept defined by the claims and the scope of equivalents.

Claims

1. A harmless treatment system for eutrophic aquaculture wastewater is characterized by comprising a sedimentation tank, a filter, a regulating tank, a mixing reactor and a reaction tank which are connected in sequence;

the mixing reactor comprises a mixing tank, a circulating pump, an air self-suction device connected with the circulating pump, an ozone self-suction device connected with the circulating pump and an ozone generator connected with the ozone self-suction device;

the air self-priming device and the ozone self-priming device have the same structure and respectively comprise a feeding pipe section communicated with the outlet end of the circulating pump, a jet flow pipe section communicated with the feeding pipe section and a discharge pipe section, one end of the discharge pipe section is communicated with the jet flow pipe section, and the other end of the discharge pipe section is communicated with the mixing tank; the jet pipe section comprises an air suction chamber, a nozzle inserted in the inlet end of the air suction chamber and an air suction pipe communicated with the air suction chamber, the inlet end of the nozzle is communicated with the feeding pipe section, the outlet end of the air suction chamber is communicated with the discharging pipe section, water output by the circulating pump sequentially passes through the feeding pipe section, the jet pipe section, the air suction chamber and the discharging pipe section and then enters the mixing tank, and in the process, the air suction pipe sucks external gas into the air suction chamber.

2. The system for harmless treatment of eutrophic aquaculture wastewater of claim 1, wherein the suction pipe is inclined toward the direction of the feed pipe section.

3. The harmless treatment system for eutrophic aquaculture wastewater of claim 2, wherein the feeding pipe section and the nozzle are in transitional connection through a first taper pipe, the outlet end of the suction chamber is in transitional connection through a second taper pipe with a throat pipe having a smaller diameter than the discharge pipe section, the throat pipe has a smaller diameter than the outlet end of the suction chamber, and the throat pipe is in transitional connection with the discharge pipe section through a third taper pipe;

the outlet of the nozzle faces the second cone.

4. The system for harmless treatment of eutrophic aquaculture wastewater as set forth in claim 3, wherein the mixing tank is cylindrical, and the water inlet pipe is connected to the mixing tank in a tangential direction; the air self-suction device and the ozone self-suction device are characterized in that discharge pipe sections of the air self-suction device and the ozone self-suction device are connected with the mixing tank along the tangential direction, and the connection positions of the discharge pipe sections and the mixing tank are located between the circulating water outlet and the water inlet pipe.

5. The system for harmless treatment of eutrophic aquaculture wastewater as recited in claim 4, wherein the output end of the ozone generator is further connected with a gas buffer tank, and an air suction pipe of the ozone self-suction device is communicated with the gas buffer tank.

6. The system for harmless treatment of eutrophic aquaculture wastewater as set forth in claim 1, wherein the filter comprises a filter tank, a buffer filter layer, a first filter layer, a second filter layer and a third filter layer sequentially disposed in the filter tank at intervals along a vertical direction;

7. The system for harmless treatment of eutrophic aquaculture wastewater as recited in claim 6, wherein the top and bottom of the filtration tank are provided with a wastewater inlet and a wastewater outlet, respectively;

8. The system for the harmless treatment of eutrophic aquaculture wastewater of claim 6, wherein the buffering filter layer is filled with: cobblestones with a diameter between 5mm and 15 mm;

9. The system for harmless treatment of eutrophic aquaculture wastewater of claim 1, wherein the treatment process of the system comprises the following steps:

6) And delivering the treated effluent in the reaction tank to the culture tank through a water pump for cyclic utilization.

10. The system for the harmless treatment of eutrophic aquaculture wastewater of claim 9, wherein the coagulant is polyaluminium chloride.