CN115626733A - Method for purification and regeneration of aquaculture wastewater - Google Patents

Abstract

A method for purifying and regenerating aquaculture wastewater belongs to the fields of resource recycling and environmental protection. It mainly includes five main processes of sedimentation and biochemistry in biochemical ponds of aquaculture wastewater, sand filtration in collection wells, oxidation, filters and filtration and adsorption towers. Among them, sedimentation biochemistry is mainly to remove feces, COD, BOD, part of ammonia nitrogen and total nitrogen and organic waste in wastewater. Phosphorus is partially converted to phosphate; oxidation is mainly to further remove ammonia nitrogen in wastewater and further convert organic phosphorus in wastewater to phosphate; filtration and adsorption phosphorus removal is to adsorb phosphate in wastewater on the filter material, so that the ammonia nitrogen in the treated water ≤1mg/L, total phosphorus ≤0.2mg/L; when using the present invention to treat aquaculture wastewater, the treatment cost is ≤0.25 yuan/ton, and has the advantage that only the wastewater needs to flow through the filter adsorption tower when treating aquaculture wastewater , does not require special personnel to operate and manage, and the operation is simple; no sludge is generated; the phosphorus adsorbed on the adsorption filter material can recover more than 90% of phosphorus resources through desorption, elution and precipitation.

Description

Method for purification and regeneration of aquaculture wastewater

technical field

The invention belongs to the fields of water resource recycling and environmental protection, and relates to a method for purifying and regenerating aquaculture wastewater.

Background technique

Aquaculture wastewater is a general term for the sewage produced in the process of seawater and freshwater aquaculture. Its COD _Cr is about 20-80mg/L, BOD ₅ is about 5-30mg/L, ammonia nitrogen is about 0.5-10mg/L, and total nitrogen is about 1-15mg /L, total phosphorus is about 0.5~8mg/L, and its main pollutants are COD _Cr , BOD ₅ , ammonia nitrogen and total phosphorus. If the aquaculture wastewater is directly discharged to the environment, it will cause COD _Cr , BOD ₅ , nitrogen and phosphorus in the surrounding water and rivers to exceed the standard, and the water body will become eutrophic. Therefore, the aquaculture wastewater must be purified and treated. COD _Cr , BOD ₅ , ammonia nitrogen and total phosphorus in aquaculture wastewater can be treated by physical, chemical and biochemical methods. Physical methods include nanofiltration, reverse osmosis, distillation, soil irrigation adsorption, adsorption and ion exchange and other treatment technologies; chemical methods include ammonia stripping, break point chlorination, incineration, chemical precipitation, catalytic cracking, electrodialysis, electrochemical strong Oxidation and other treatment technologies; biological methods include activated sludge method, biofilm method, algae cultivation and aquatic plant cultivation (artificial wetland) and other treatment technologies. Although the activated sludge method, the biofilm method and the constructed wetland are all very successful methods in the practice of sewage treatment, and are widely used in various urban sewage treatment and industrial wastewater treatment projects, but they are still used in aquaculture sewage treatment. No or lack of success stories. Due to the low COD _Cr and BOD ₅ in aquaculture wastewater, the ratio of carbon, nitrogen, and phosphorus is seriously out of balance, the use of biochemical methods or artificial wetlands not only requires a large investment and occupies a large area, but also continuously adds carbon sources during operation, resulting in treatment High cost and poor operation effect; when the precipitation method is used to remove total phosphorus, the dosage of coagulant is as high as 120-300g/m ³ , and a large amount of sludge is generated, not only the phosphorus removal effect is poor, but also the cost is as high as 0.6 yuan/m ³ or more is not only technically difficult to achieve, but also not allowed from an economic point of view; in addition, aquaculture consumes a lot of water and frequently changes water. If regeneration and recycling are not carried out, not only a lot of water resources will be wasted, but also because of the discharge of aquaculture sewage. A body of water that pollutes ten times as much as discharges. Therefore, along with the development of aquaculture industry, there is an urgent need for an economical and practical sewage purification and regeneration device and method thereof that can realize the purification and recycling of aquaculture sewage.

Contents of the invention

In order to solve the above technical problems, the object of the present invention is to provide a method for purifying and regenerating aquaculture wastewater.

The present invention is realized by the following technical solutions: a method for purifying and regenerating aquaculture wastewater, which is processed according to the following steps:

(1) Precipitation biochemistry: discharge the aquaculture wastewater into the biochemical pond 100, through the biochemical precipitation of solid particles such as feces and residual feed in the wastewater, and at the same time, the COD and BOD in the wastewater are oxidized into CO ₂ through the action of microorganisms, and the organic phosphorus converted into inorganic acid radicals;

(2) Sand filtration in the water collection well 200: collect the aquaculture sewage that has undergone biochemical precipitation in the water collection well 200 with filter sand in the waste water, and pump it into the reaction pool/tank 300 through the waste water inlet pipe with a pump;

(3) Oxidation: Add 20% sodium hydroxide solution at 100-300ml/L, adjust the pH of the wastewater to 7.5-8.8, and simultaneously add 10-12% commercial sodium hypochlorite at 50-200ml/L, and mix well , enter the reaction tank/tank 300 for oxidation reaction, and oxidize the ammonia nitrogen in the waste water to nitrogen;

(4) Filtration: pump the oxidized waste water into the filter 400, further filter and remove tiny solid particles in the waste water, and then flow out from the water outlet of the filter 400 and enter the filter adsorption tower 500;

(5) Phosphorus removal by filtration and adsorption: the wastewater flows from top to bottom, and the phosphate anions in the sewage are adsorbed by the adsorbent to remove phosphorus in the wastewater. into natural water bodies;

After filtration and adsorption to remove phosphorus, the total phosphorus in the effluent is ≦0.1mg/L, and the removal rate of phosphorus is 90-99.5%;

(6) Regeneration of filter adsorption packing: track and detect the total phosphorus concentration of the effluent in time. When the total phosphorus concentration of the effluent is close to the set value, first turn off the waste water lifting pump, and then close the water inlet of the filter adsorption tower and the outlet of the filter adsorption tower ; Open the inlet of the backwash liquid of the filter adsorption tower, pump the regeneration liquid (analysis liquid) into the filter adsorption tower to the liquid level with the regeneration liquid delivery pump, backwash and regenerate for 60 to 90 minutes, and absorb the The phosphate root in the filter is eluted, and the elution regeneration liquid is pumped into the phosphorus recovery reaction tank (tank) through the regeneration desorption liquid delivery pump of the backwash liquid outlet of the filter adsorption tower; after the desorption is completed, wash it with water until the performance, that is, to complete the regeneration of the adsorption packing;

(7) Phosphorus recovery: pump the 600° backwash eluent into the phosphorus recovery reaction tank (tank), add phosphorus precipitant, and stir for reaction, so that the phosphate radical in the recovery liquid reacts with calcium ions to form calcium phosphate precipitation, and the reaction The final backwashing solution is injected into the phosphorus sedimentation tank 620, precipitated and separated, and dried to obtain recovered calcium phosphate;

The adsorption packing of the filter adsorption tower is a special packing for iron-based oxyhydroxide phosphorus adsorption, with a bulk density of 0.40kkg/m ³ and an adsorption capacity of 1 kg/m ^{3 ;}

The thickness of the adsorption filler filled in the filter adsorption tower is 1000-2000mm;

The phosphorus precipitating agent is a clear saturated calcium hydroxide solution or a 5-25% calcium chloride solution.

The present invention has following beneficial effect:

1. The biochemistry of the oxidation pond is mainly to oxidize and remove COD and BOD in the water body, and at the same time to precipitate and separate the feces and residual feed in the sewage; the chemical strong oxidation is mainly to remove the ammonia nitrogen in the wastewater and convert the organic phosphorus in the wastewater into phosphate; adsorption is to convert The phosphate radical in the wastewater is adsorbed on the filter material, so that the ammonia nitrogen in the treated water body is ≤1mg/L, and the total phosphorus is ≤0.1mg/L. The desorption is to elute the saturated filler, so that the adsorption filler can restore the phosphorus adsorption function;

2. The purified effluent has high quality and can be recycled: when the present invention is used to purify and regenerate aquaculture wastewater, the purified effluent quality can reach the water quality of surface III in the Environmental Quality Standard for Surface Water (GB3838-2002). Can be used as water recycling for aquaculture;

3. Low purification cost: when the present invention is used to purify and regenerate aquaculture wastewater, the treatment cost is ≤0.25 yuan/ton, which is low. In addition, the purified water has reached the recycling standard for reuse, which is cheaper than buying water It is half as low, which not only greatly realizes the recycling of water resources, but also reduces the cost of aquaculture water;

4. The recovery of phosphorus resources is realized without sludge: during the purification process, phosphorus is adsorbed on the special filler for phosphorus adsorption, and after saturation, it is eluted and regenerated with 0.5-1% sodium hydroxide solution, and phosphorus is transferred to sodium hydroxide solution In the process, saturated lime water or calcium chloride is added to the sodium hydroxide solution, and the phosphate radical and calcium ion form calcium phosphate precipitation, thereby recovering phosphorus resources, and there is no sludge in the whole process.

5. Simple operation: when using the present invention to purify, regenerate and recycle aquaculture wastewater, the whole process is controlled by PLC and artificial intelligence, and no special personnel are required for operation and management, and the operation is simple;

6. Realize the recovery of phosphorus resources for self-use: the phosphorus adsorbed on the adsorption filter material is desorbed and eluted, and saturated lime water or calcium chloride is added to the desorption solution, and the phosphate radical and calcium ion form calcium phosphate precipitation, which can be recovered by 90% above phosphorus resources.

Description of drawings:

Accompanying drawing 1 is process flow block diagram of the present invention;

Accompanying drawing 2 is the structural representation of biochemical pond of the present invention;

Accompanying drawing 3 is the structural representation of water collecting well of the present invention;

Accompanying drawing 4 is the schematic diagram of the filter adsorption and desorption of phosphorus;

Accompanying drawing 5 is the sewage treatment inlet and outlet water quality table of embodiment 1 of the present invention;

Accompanying drawing 6 is the biochemical pond inlet and outlet water index inlet and outlet water quality table of embodiment 1 of the present invention eel culture sewage;

Accompanying drawing 7 is the chemical oxidation tank oxidation water inlet and outlet water index inlet and outlet water quality table of embodiment 1 of the present invention eel culture sewage;

Accompanying drawing 8 is the filter adsorption dephosphorization inlet and outlet water index inlet and outlet water quality table of embodiment 1 of the present invention eel culture sewage;

Accompanying drawing 9 is the influent index and the effluent standard index water quality table of the embodiment of the present invention 2 Penaeus vannamei culture sewage;

Accompanying drawing 10 is the indicator water quality table of the biochemical pond inflow and outflow of the whiteleg shrimp culture sewage of the embodiment of the present invention 2;

Accompanying drawing 11 is the indicator water quality table of the chemical oxidation tank oxidation inlet and outlet water of embodiment 2 of the present invention Penaeus vannamei culture sewage;

Accompanying drawing 12 is the influent index water quality table of the bullfrog breeding sewage to be treated in Embodiment 3 of the present invention;

Accompanying drawing 13 is the inflow and outflow index water quality table of the embodiment of the present invention 3 bullfrog culture sewage;

Accompanying drawing 14 is the biochemical pond inlet and outlet water index water quality table of the embodiment of the present invention 3 bullfrog breeding sewage;

Accompanying drawing 15 is the chemical oxidation tank oxidation inlet and outlet water index water quality table of the embodiment of the present invention 3 bullfrog breeding sewage;

Accompanying drawing 16 is the index water quality table of filter adsorption dephosphorization inflow and outflow water of bullfrog breeding sewage in Example 3 of the present invention.

Detailed ways:

A method for purifying and regenerating aquaculture wastewater,

Follow the steps below:

(1) Precipitation biochemistry: discharge the aquaculture wastewater into the biochemical pond 100, through the biochemical precipitation of solid particles such as feces and residual feed in the wastewater, and at the same time, the COD and BOD in the wastewater are oxidized into CO ₂ through the action of microorganisms, and the organic phosphorus converted into inorganic acid radicals;

(2) Sand filtration in the water collection well 200: collect the aquaculture sewage that has undergone biochemical precipitation in the water collection well 200 with filter sand in the waste water, and pump it into the reaction pool/tank 300 through the waste water inlet pipe with a pump;

(3) Oxidation: Add 20% sodium hydroxide solution at 100-300ml/L, adjust the pH of the wastewater to 7.5-8.8, and simultaneously add 10-12% commercial sodium hypochlorite at 50-200ml/L, and mix well , enter the reaction tank/tank 300 for oxidation reaction, and oxidize the ammonia nitrogen in the waste water to nitrogen;

NH ₄ ⁺ + NaClO —→ NH ₂ Cl + H ₂ O + Na ⁺ (monochloramine)

NH ₂ Cl + NaClO —→ NHCl ₂ + H ₂ O + Na ⁺ (Dichloramine)

2NH ₂ Cl +NaClO—→ N ₂ ↑+ 3HCl + H ₂ O+Na ⁺ (Main denitrification reaction 1)

The overall reaction formula:

2NH ₄ ⁺ + 3NaClO —→ N ₂ ↑+ 3HCl + H ₂ O+3Na ⁺

(4) Filtration: pump the oxidized waste water into the filter 400, further filter and remove tiny solid particles in the waste water, and then flow out from the water outlet of the filter 400 and enter the filter adsorption tower 500;

(5) Phosphorus removal by filtration and adsorption: the wastewater flows from top to bottom, and the phosphate anions in the sewage are adsorbed by the adsorbent to remove phosphorus in the wastewater. into natural water bodies;

After filtration and adsorption to remove phosphorus, the total phosphorus in the effluent is ≦0.1mg/L, and the removal rate of phosphorus is 90-99.5%;

Reaction formula (adsorption reaction):

Fe-OOH+H ₂ PO ₄ ^- = Fe-O-HPO ₄ ^- +H ₂ O

(6) Regeneration of filter adsorption packing: track and detect the total phosphorus concentration of the effluent in time. When the total phosphorus concentration of the effluent is close to the set value, first turn off the waste water lifting pump, and then close the water inlet of the filter adsorption tower and the outlet of the filter adsorption tower ; Open the inlet of the backwash liquid of the filter adsorption tower, pump the regeneration liquid (analysis liquid) into the filter adsorption tower to the liquid level with the regeneration liquid delivery pump, backwash and regenerate for 60 to 90 minutes, and absorb the The phosphate root in the filter is eluted, and the elution regeneration liquid is pumped into the phosphorus recovery reaction tank (tank) through the regeneration desorption liquid delivery pump of the backwash liquid outlet of the filter adsorption tower; after the desorption is completed, wash it with water until the performance, that is, to complete the regeneration of the adsorption packing;

Reaction formula (desorption reaction):

Fe-O-HPO ₄ ^- +3OH ^- = Fe-OOH+PO ₄ ^3- +OH ^- +H ₂ O

(7) Phosphorus recovery: pump the 600° backwash eluent into the phosphorus recovery reaction tank (tank), add phosphorus precipitant, and stir for reaction, so that the phosphate radical in the recovery liquid reacts with calcium ions to form calcium phosphate precipitation, and the reaction The final backwashing solution is injected into the phosphorus sedimentation tank 620, precipitated and separated, and dried to obtain recovered calcium phosphate;

Reaction formula (precipitation and crystallization reaction):

PO ₄ ^3- +3/2Ca(OH) ₂ = 1/2Ca ₃ (PO ₄ ) ₂ + ^3OH-

The principle of phosphorus removal from aquaculture wastewater is as follows:

The reaction equations of adsorption, desorption and phosphorus resource recovery are as follows:

Phosphorus removal from sewage (adsorption reaction)

Fe-OOH+H ₂ PO ₄ ^- = Fe-O-HPO ₄ ^- +H ₂ O

Sorbent regeneration (desorption reaction)

Fe-O-HPO ₄ ^- +3OH ^- = Fe-OOH+PO ₄ ^3- +OH ^- +H ₂ O

Phosphorus resource recovery (flocculation crystallization reaction)

PO ₄ ^3- +3/2Ca(OH) ₂ = 1/2Ca ₃ (PO ₄ ) ₂ + ^3OH-

The adsorption packing of the filter adsorption tower is a special packing for iron-based oxyhydroxide phosphorus adsorption, with a bulk density of 0.40kkg/m ³ and an adsorption capacity of 1 kg/m ^{3 ;}

The thickness of the adsorption filler filled in the filter adsorption tower is 1000-2000mm;

The phosphorus precipitating agent is a clear saturated calcium hydroxide solution or a 5-25% calcium chloride solution.

Example 1

The method of purification and regeneration of 500 tons/day eel breeding wastewater:

Referring to Figures 1 to 4, this embodiment provides a method for purifying and regenerating aquaculture wastewater. The wastewater from eel cultivation is directly discharged into the biochemical pond 100, and the feces and residual feed of the eels discharged in the water are naturally discharged in the biochemical pond. Precipitate and oxidize for 4 to 10 hours, COD _Cr and BOD ₅ in the wastewater are oxidized to carbon dioxide by microorganisms in the water body, and ammonia nitrogen is oxidized to nitrate at the same time, and a large amount of phosphorus-containing organic matter in the wastewater is oxidized and decomposed into inorganic phosphate;

In this embodiment, the influent indicators and effluent compliance indicators of the eel breeding wastewater to be treated are shown in Figure 5.

A method for purifying and regenerating aquaculture wastewater adopted in this embodiment includes collecting and discharging the eel breeding wastewater into the biochemical pond 100, and entering into the water collection well 200 with sand filter after sedimentation and biochemistry. See attached drawing 6;

After sedimentation and biochemistry, enter the water collection well 200 with sand filter and use the wastewater lift pump to pump the eel culture wastewater into the reaction tank (tank) 300, add 10-12% commercial sodium hypochlorite at a rate of 100ml/L, and mix through the pipeline mixer Evenly, enter the reaction pool (tank) 300 for oxidation reaction.

See accompanying drawing 7 for the pollutant index of eel culture wastewater after chemical oxidation;

It can be seen from Figure 7 that the reaction tank (tank) 300 of the eel breeding wastewater treatment system can oxidize the ammonia nitrogen in the sewage from 3 mg/L to less than 0.5 mg/L, and the total phosphorus concentration remains unchanged after the oxidation treatment.

The oxidized eel breeding wastewater flows into the filter 400, and then flows into the phosphorus filtration and adsorption tower 500 with a flow rate of 21m ³ /H.

Track and detect the total phosphorus concentration of the effluent in time. When the total phosphorus concentration of the effluent is close to the set value, first turn off the waste water lifting pump, first turn off the waste water lifting pump, and then close the water inlet of the filter adsorption tower and the water outlet of the filter adsorption tower; The water inlet of the backwash liquid of the above-mentioned filter adsorption tower is pumped with the regeneration liquid delivery pump to the regeneration liquid (analysis liquid) into the filter adsorption tower to the liquid level, and the backwash is regenerated for 60 to 90 minutes to remove the phosphoric acid adsorbed in the adsorption packing. The root is eluted, and the eluted regeneration liquid is pumped into the phosphorus recovery reaction tank (tank) through the regeneration desorption liquid delivery pump at the backwash liquid outlet of the filter adsorption tower; Complete adsorption packing regeneration;

Pump the back-elution elution solution pumped into the phosphorus recovery reaction pool (tank) 600, add phosphorus precipitant, stir and react, so that the phosphate radical in the recovery solution reacts with calcium ions to form calcium phosphate precipitation, and the back-elution solution after the reaction Inject into the phosphorus sedimentation tank, precipitate and separate, and dry to obtain recovered calcium phosphate.

It can be seen from Figure 9 that after eel breeding wastewater has been treated by biochemical, chemical strong oxidation, precision filtration and filtration adsorption, the ammonia nitrogen in the effluent is ≤0.5mg/L, the total phosphorus is ≤0.2mg/L, and the ammonia nitrogen and total phosphorus indicators in the effluent It complies with the Class III water index corresponding to Table 1 of "Surface Water Environmental Quality Standard" (GB3838-2002).

Example 2

Method for purifying and regenerating 1000 tons/day of Penaeus vannamei farming wastewater:

Referring to Figures 1 to 4, a method for purification and regeneration of Penaeus vannamei wastewater provided in this example includes two steps of oxidation and filtration and adsorption in sequence, specifically:

The eel breeding wastewater is collected and discharged into the biochemical pond 100 for sedimentation and biochemistry.

See Figure 15 for the removal effect of biochemical precipitation on the pollutant indicators of Penaeus vannamei aquaculture wastewater.

As can be seen from accompanying drawing 10, the strong chemical oxidation device 300 of described Penaeus vannamei breeding wastewater treatment system can biochemically contain COD in wastewater from 80mg/L to below 20mg/L, and the oxidation of ammonia nitrogen from 10mg/L to less than 3mg/L L, the total phosphorus concentration is biochemically from 1.5mg/L to below 1mg/L.

The waste water after the biochemical precipitation enters in the water collection well 200 with sand filter, and the culture waste water of Penaeus vannamei is pumped into the reaction tank (tank) 300 with the waste water lift pump, and 10-12% commercial sodium hypochlorite is added by adding 120ml/L, and Mix evenly through the pipeline mixer, enter the reaction pool (tank) 300 to carry out the oxidation reaction.

Refer to Figure 11 for the pollutant indicators of the oxidized Penaeus vannamei farming wastewater.

It can be seen from accompanying drawing 11 that the strong chemical oxidation device 300 of the Penaeus vannamei breeding wastewater treatment system can oxidize the ammonia nitrogen in the wastewater from 10mg/L to less than 0.5mg/L, and the total phosphorus concentration remains unchanged after the oxidation treatment.

The oxidized Penaeus vannamei breeding wastewater flows into the filter 400, and then flows into the phosphorus filtration and adsorption tower 500 after filtration. The flow rate is 42m ³ /H.

It can be seen from Figure 12 that after the five steps of biochemical sedimentation, sand filtration in collection wells, oxidation, filtration and filtration and adsorption, the ammonia nitrogen in the effluent is ≤0.5mg/L, and the total phosphorus in the effluent is ≤0.2mg/L. The indicators of ammonia nitrogen and total phosphorus meet the category III water indicators corresponding to Table 1 of the Environmental Quality Standards for Surface Water (GB3838-2002). The regeneration of the filter adsorption tower and the recovery of phosphorus are the same as in Example 1, and are not described again.

Example 3

The method of 500 tons/day bullfrog breeding waste water

Referring to Figures 1-4, this embodiment provides a method for purifying and regenerating bullfrog wastewater. In this embodiment, the influent indicators and effluent compliance indicators of the bullfrog breeding wastewater to be treated are shown in Figure 13.

The bullfrog breeding wastewater is collected and discharged into the biochemical pond 100, and enters the water collection well 200 with sand filter after sedimentation and biochemistry, and enters the water collection well 200 with sand filter after sedimentation and biochemistry.

Refer to Figure 14 for the pollutant indicators of the bullfrog breeding wastewater that has been biochemically passed through the biochemical pond.

As can be seen from accompanying drawing 14, the biochemical pond 100 of described bullfrog breeding wastewater treatment system can oxidize the COD in the wastewater from 80mg/L to less than 30mg/L, the oxidation of ammonia nitrogen from 10mg/L to less than 3mg/L, precipitation After biochemical treatment, the total phosphorus concentration was oxidized from 3mg/L to less than 1.5mg/L.

Pump bullfrog breeding wastewater into the reaction tank (tank) 300 after biochemical treatment with a wastewater lifting pump, add 10-12% commercial sodium hypochlorite at a rate of 100ml/L, mix evenly through a pipeline mixer, and enter the reaction tank (tank) 110 carry out the oxidation reaction.

See Figure 15 for the pollutant indicators of the bullfrog breeding wastewater after chemical oxidation.

As can be seen from accompanying drawing 15, the oxidation of chemical oxidation device 300 of described bullfrog breeding wastewater treatment system can be contained in the oxidation of COD in wastewater from 30mg/L to be less than 20mg/L, the oxidation of ammonia nitrogen from 3mg/L to be less than 0.5mg/L L, Total phosphorus concentration remains unchanged after chemical oxidation treatment.

The bullfrog breeding wastewater after chemical oxidation treatment flows into the filter 400, and then flows into the phosphorus filtration and adsorption tower 500 after filtration. The flow rate is 21m ³ /H.

It can be seen from Figure 16 that the COD _Cr of the effluent is ≤20mg/L, the ammonia nitrogen is ≤0.5mg/L, and the total phosphorus is ≤0.2mg/L after the five steps of sedimentation biochemistry, strong chemical oxidation, precision filtration and filtration adsorption are used to treat the bullfrog breeding wastewater. L. The ammonia nitrogen and total phosphorus indicators of the effluent meet the category III water indicators corresponding to Table 1 of the "Surface Water Environmental Quality Standards" (GB3838-2002).

The foregoing description shows and describes preferred embodiments of the present invention, and as previously stated, it is to be understood that the present invention is not limited to the form disclosed herein and should not be construed as excluding other embodiments but may be applied to various other embodiments. Combinations, modifications and circumstances, and can be modified within the scope of the inventive concept described herein, by the above teachings or by skill or knowledge in the relevant field. However, changes and changes made by those skilled in the art do not depart from the spirit and scope of the present invention, and should all be within the protection scope of the appended claims of the present invention.

Claims (4)

1. A method for purifying and regenerating aquaculture wastewater is characterized by comprising the following steps:

the method comprises the following steps:

(1) And (3) precipitation and biochemistry: discharging the aquaculture wastewater into a biochemical pond, and biochemically precipitating feces and residual feed in the wastewaterSolid particles such as materials, and the like, and simultaneously oxidize COD and BOD in the wastewater into CO through the action of microorganisms ₂ Converting the organic phosphorus into inorganic acid radical;

(2) Sand filtration of a water collecting well 200: collecting the biochemically precipitated breeding sewage in a collecting well with wastewater and sand filtration, and pumping the breeding sewage into a reaction tank/tank by a pump through a wastewater inlet pipe;

(3) And (3) oxidation: adding 20% sodium hydroxide solution according to 100-300 ml/L, adjusting the pH value of the wastewater to 7.5-8.8, synchronously adding 10-12% commercial sodium hypochlorite according to 50-200 ml/L, uniformly mixing, entering a reaction tank for oxidation reaction, and oxidizing ammonia nitrogen in the wastewater into nitrogen;

(4) And (3) filtering: pumping the oxidized wastewater into a filter, further filtering to remove tiny solid small particles in the wastewater, then flowing out of a water outlet of the filter, and entering a filtering adsorption tower;

(5) Filtering, adsorbing and removing phosphorus: the wastewater flows out from top to bottom, phosphate anions in the wastewater are adsorbed by the adsorbent to remove phosphorus in the wastewater, and the clear water after phosphorus removal is measured by a flowmeter through a water outlet of the filtering adsorption tower and then discharged into a natural water body;

after the phosphorus is removed by filtration and adsorption, the total phosphorus in the effluent is less than or equal to 0.1mg/L, and the phosphorus removal rate is 90-99.5%;

(6) Regeneration of the filtering and adsorbing filler: the total phosphorus concentration of the effluent is tracked and detected in time, and when the total phosphorus concentration of the effluent is close to a set value, the wastewater lift pump is closed, and then the water inlet of the filtration adsorption tower and the water outlet of the filtration adsorption tower are closed; opening a backwash liquid inlet of the filtration and adsorption tower, pumping a regeneration liquid (analytic liquid) into the filtration and adsorption tower by using a regeneration liquid conveying pump to reach a liquid level, carrying out backwashing regeneration for 60-90 minutes, eluting phosphate radicals adsorbed in the adsorption filler, and pumping the eluted regeneration liquid into a phosphorus recovery reaction tank (tank) by using a regeneration desorption liquid conveying pump at a backwash liquid outlet of the filtration and adsorption tower; after the desorption is finished, washing the adsorbent with clear water to be neutral, and finishing the regeneration of the adsorption filler;

(7) And (3) recovering phosphorus: adding a phosphorus precipitator into the backwashing desorption liquid pumped into the phosphorus recovery reaction tank (pot), stirring for reaction, reacting phosphate radicals in the recovery liquid with calcium ions to generate calcium phosphate precipitate, injecting the backwashing desorption liquid after reaction into a phosphorus precipitation tank 620, separating the precipitate, and drying to obtain the recovered calcium phosphate.

2. The method for purifying and regenerating aquaculture wastewater as claimed in claim 1, wherein the method comprises the following steps: the adsorption filler of the filtration adsorption tower is iron-based oxyhydroxide phosphorus adsorption special filler, and the bulk density of the adsorption filler is 0.40 kg/m ³ The adsorption capacity is 1 kg/m ³ 。

3. The method for purifying and regenerating aquaculture wastewater as claimed in claim 1, wherein the method comprises the following steps: the thickness of the adsorption filler filled in the filtration adsorption tower is 1000-2000 mm.

4. The method for purifying and regenerating aquaculture wastewater as claimed in claim 1, wherein the method comprises the following steps: the phosphorus precipitator is a clear saturated calcium hydroxide solution or a 5-25% calcium chloride solution.

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