Process for the reuse of wastewater in sustainable coastal underground brine aquaculture

Abstract

The present application relates to a kind of sustainable coastal underground brine aquaculture wastewater reuse process, and the process is sequentially carried out biochemical treatment, ozone sterilization and oxidation, advanced oxidation, catalytic oxidation combined treatment and filtration treatment to composite type treatment to aquaculture wastewater, comprising the following steps: S1, primary treatment is carried out in aquaculture wastewater pool;S2, under the action of water pump, tail water is sequentially subjected to ozone sterilization pre-oxidation treatment, quartz sand filtration treatment, hydroxyl radical oxidation treatment, ozone catalytic oxidation treatment, carbon filtration treatment, softening treatment, and the filtered water is divided into two ways after ultrafiltration treatment;S3, the water in the recycling clean water tank is pumped into aquaculture workshop, and the wastewater in the aquaculture workshop is discharged into aquaculture wastewater pool.The present application has the advantages of: it can efficiently realize the recycling of wastewater, the water quality index is better than the pond aquaculture tail water discharge standard, and there is no secondary pollution, stable and reliable operation, low cost, and has the effect of green water product environmental protection aquaculture.

Description

Technical Field

[0001] This invention relates to a sustainable process for recycling wastewater from coastal underground brine aquaculture, which belongs to the field of green environmental protection. Background Technology

[0002] Aquaculture provides humans with high-quality animal protein and plays a vital role in addressing global food issues. The treatment of aquaculture wastewater is receiving increasing attention.

[0003] Existing methods for treating aquaculture wastewater mainly employ outdoor sedimentation tanks with sedimentation and aeration, as well as biodegradation, bioabsorption, accumulation, and conversion. These methods have drawbacks, such as large land area requirements, unsatisfactory wastewater treatment results in winter, and the inability to recycle wastewater after aquaculture due to substandard treatment indicators. Summary of the Invention

[0004] To overcome the shortcomings of existing technologies, this invention provides a sustainable process for recycling and reusing wastewater from coastal underground brine aquaculture. The technical solution of this invention is as follows:

[0005] A sustainable coastal underground brine aquaculture wastewater reuse process includes the following steps: biochemical treatment to degrade total nitrogen / ammonia nitrogen and some COD, combined ozone sterilization / advanced oxidation / catalytic oxidation, and filtration.

[0006] S1. The underground brine is introduced into the aquaculture wastewater conditioning biological treatment tank through a water replenishment pump. At the same time, biological carbon source and denitrifying bacteria are added to the aquaculture wastewater conditioning biological treatment tank to remove TN, TP and COD from the underground brine to form effluent.

[0007] S2. Under the action of the water pump, the effluent sequentially undergoes ozone sterilization and disinfection pre-oxidation, quartz sand filtration, hydroxyl radical oxidation, ozone catalytic oxidation, carbon filtration, softening, primary fine filtration, secondary fine filtration, and ultrafiltration before being divided into two streams. One stream forms concentrated water, which is purified and recycled; the other stream enters a compliant reuse water tank, where high-density, high-dissolved-oxygen purified water is formed, with an oxygen content of 15-25 mg / L. The ozone required during the ozone sterilization and disinfection pre-oxidation, hydroxyl radical oxidation, and ozone catalytic oxidation processes is high-concentration ozone, with a concentration of 350 mg / L. The ozone is produced through an ozone preparation process; the specific ozone preparation process is as follows:

[0008] S2-1. The gas produced by the screw air compressor passes through the gas storage tank, refrigerated dryer, purifier, filter, PSA oxygen generator, ozone generator and anti-backflow protection device in sequence to form high-concentration ozone.

[0009] S2-2, The moisture generated from the gas storage tank, refrigerated dryer, purifier and filter is automatically discharged; the cold water required by the ozone generator is provided by an industrial chiller;

[0010] S3. The purified water in the compliant reuse water tank passes through RO reverse osmosis and enters the pure water tank. After passing through RO reverse osmosis, the purified water forms concentrated brine, which is used to condense industrial salt. The purified water in the compliant reuse water tank passes through salinity adjustment and enters the makeup water pump. The water in the pure water tank and the salinity-adjusted purified water merge at the inlet of the makeup water pump and then flow back to the compliant reuse water tank through the makeup water pump. The purified water in the compliant reuse water tank enters the aquaculture workshop after passing through the reuse water pump. The sewage in the aquaculture workshop is discharged into the aquaculture sewage conditioning biological treatment tank.

[0011] The wastewater treatment process involves three stages of ozone oxidation: first-stage ozone oxidation is carried out through an ozone sterilization and disinfection pre-oxidation unit; second-stage advanced oxidation is carried out through a hydroxyl radical oxidation unit; and third-stage catalytic oxidation is carried out through an ozone catalytic oxidation unit.

[0012] A quartz sand filtration step is provided between the primary and secondary ozone oxidation steps, which is completed by a quartz sand filtration unit; the carbon filtration is completed by a carbon filtration unit; the softening step is completed by a softening unit; the primary and secondary fine filtration steps are completed by a fine filtration unit; and the ultrafiltration step is completed by a fully automatic ultrafiltration unit. The primary, secondary, and ultrafiltration steps are used to filter the effluent, removing small particulate solids, organic matter, and microorganisms from the filtrate, thereby further improving the purification and filtration effect on aquaculture wastewater and forming a qualified filtrate.

[0013] The biocarbon source includes any one of bran, straw, wheat husk, rice husk, and corn cob.

[0014] The wastewater is treated by ozone catalytic oxidation to form compliant discharge water that flows into a reuse pond for recycling.

[0015] The advantages of this invention are: by performing a combined treatment of aquaculture wastewater through biochemical treatment, ozone sterilization / oxidation / advanced oxidation / catalytic oxidation treatment and filtration treatment, the wastewater reclaimed water quality indicators are efficiently achieved, energy consumption and aquaculture costs are reduced, and there is no secondary pollution. The operation is stable and reliable, the cost is low, and it has a green and environmentally friendly effect.

[0016] It can efficiently reuse and recycle wastewater (i.e., aquaculture tailwater) with water quality indicators that are better than the latest and highest level standards: namely [Pond Aquaculture Tailwater Discharge Standard (DB32 / 4043-20210)], and there is no secondary pollution. It is stable and reliable in operation, low in cost, and has the effect of green aquaculture and environmental protection. Attached Figure Description

[0017] Figure 1 This is a flowchart illustrating the present invention. Detailed Implementation

[0018] The present invention will be further described below with reference to specific embodiments, and the advantages and features of the present invention will become clearer as a result. However, these embodiments are merely exemplary and do not constitute any limitation on the scope of the present invention. Those skilled in the art should understand that modifications or substitutions can be made to the details and form of the technical solutions of the present invention without departing from the spirit and scope of the present invention, but all such modifications and substitutions fall within the protection scope of the present invention.

[0019] See Figure 1 This invention relates to a sustainable coastal underground brine aquaculture wastewater reuse and recycling process. This process involves a combination of biochemical treatment, ozone sterilization and oxidation, advanced oxidation, catalytic oxidation, and filtration to treat the aquaculture wastewater. Specifically, it includes the following steps:

[0020] S1. The underground brine is introduced into the aquaculture wastewater conditioning biochemical tank through a water replenishment pump. At the same time, biological carbon source (including any one of bran, straw, wheat husk, rice husk, and corn cob) and denitrifying bacteria are added to the aquaculture wastewater conditioning biochemical tank to remove TN, TP and COD from the underground brine, forming effluent.

[0021] S2. Under the action of the water pump, the effluent sequentially undergoes ozone sterilization and disinfection pre-oxidation, quartz sand filtration, hydroxyl radical oxidation, ozone catalytic oxidation, carbon filtration, softening, primary fine filtration, secondary fine filtration, and ultrafiltration before being divided into two streams. One stream forms concentrated water, which is purified and recycled; the other stream enters a compliant reuse water tank, where high-density, high-dissolved-oxygen purified water is formed, with an oxygen content of 15-25 mg / L. During the ozone sterilization and disinfection pre-oxidation, hydroxyl radical oxidation, and ozone catalytic oxidation processes, a high-concentration ozone is required, with a concentration of 350 mg / L (currently the top concentration for large-scale ozone generators both domestically and internationally). This ozone concentration of 350 mg / L is typical domestically and internationally, being <200 mg / L. High-concentration ozone has a significant effect on water treatment. The ozone is produced through an ozone preparation process. The specific ozone preparation process is as follows:

[0022] S2-1. The gas produced by the screw air compressor passes through the gas storage tank, refrigerated dryer, purifier, filter, PSA oxygen generator, ozone generator and anti-backflow protection device in sequence to form high-concentration ozone.

[0023] S2-2, The moisture generated from the gas storage tank, refrigerated dryer, purifier and filter is automatically discharged; the cold water required by the ozone generator is provided by an industrial chiller;

[0024] S3. The purified water in the compliant reuse water tank passes through RO reverse osmosis and enters the pure water tank. After passing through RO reverse osmosis, the purified water forms concentrated brine, which is used to produce industrial salt. The purified water in the compliant reuse water tank passes through salinity adjustment and enters the makeup water pump. The water in the pure water tank and the salinity-adjusted purified water are combined at the inlet of the makeup water pump and then flow back to the compliant reuse water tank through the makeup water pump. The purified water in the compliant reuse water tank passes through the reuse water pump and enters the aquaculture workshop. The wastewater in the aquaculture workshop is discharged into the aquaculture wastewater conditioning biochemical tank for recycling.

[0025] The wastewater treatment process involves three stages of ozone oxidation: first-stage ozone oxidation is carried out through an ozone sterilization and disinfection pre-oxidation unit; second-stage advanced oxidation is carried out through a hydroxyl radical oxidation unit; and third-stage catalytic oxidation is carried out through an ozone catalytic oxidation unit.

[0026] A quartz sand filtration step is provided between the primary and secondary ozone oxidation steps, which is completed by a quartz sand filtration unit; the carbon filtration is completed by a carbon filtration unit; the softening step is completed by a softening unit; the primary and secondary fine filtration steps are completed by a fine filtration unit; and the ultrafiltration step is completed by a fully automatic ultrafiltration unit. The primary, secondary, and ultrafiltration steps are used to filter the effluent, removing small particulate solids, organic matter, and microorganisms from the filtrate, thereby further improving the purification and filtration effect on aquaculture wastewater and forming a qualified filtrate.

[0027] The ozone catalytic oxidation unit (patent number: 201410155695.0, invention title: A catalytic oxidation ozone deodorization system) has been applied for, and includes a negative pressure ozone reaction tower, a positive pressure composite catalyst reaction tower, a pH aqueous solution adjustment and circulation tank, a PLC microcomputer controller, an air oxygen generation system, and an ozone generator; the positive pressure composite catalyst reaction tower contains a composite catalyst, which is an alumina ceramic hollow sphere carrier with a loading material on its skeleton. The loading material is rare earth, Pt, and Pb, and the mass fractions of the alumina ceramic hollow sphere carrier, rare earth, Pt, and Pb are 35-45%, 18-22%, 15%, and 22-28%, respectively; the positive pressure composite catalyst reaction tower is equipped with a spiral nozzle, and the air inlet of the negative pressure ozone reaction tower is connected to an exhaust pipe, and the air outlet... The air supply system is connected to the air inlet of the positive pressure composite catalyst reaction tower via an induced draft fan. The induced draft duct contains a fan. The positive pressure composite catalyst reaction tower has two outlets: one outlet directly discharges compliant gas, and the other outlet is connected via a pipe to the inlet of a pH aqueous solution regulating circulation tank. The outlet of the pH aqueous solution regulating circulation tank is connected via a booster pump to a spiral nozzle inside the positive pressure composite catalyst reaction tower. The air outlet of the oxygen generation system is connected via a pipe to the air inlet of the ozone generator. The outlet of the ozone generator is connected via pipes to the air inlets of both the negative pressure ozone reaction tower and the positive pressure composite catalyst reaction tower. The oxygen generation system, ozone generator, induced draft fan, and booster pump are all controlled by a PLC microcomputer controller. The pH aqueous solution regulating circulation tank contains an alkaline aqueous solution with a pH value of 8-9.

[0028] The wastewater is treated by ozone catalytic oxidation to form compliant discharge water that flows into a reuse pond for recycling.

[0029] This invention utilizes ozone oxidation (including oxidation by the strongest oxidant - hydroxyl radicals), biochemical treatment through the addition of biological carbon sources and denitrifying bacteria, and supplemented by multi-stage filtration units to complete the treatment of multiple wastewaters, thereby achieving wastewater recycling.

[0030] In the wastewater treatment process of this invention, the high-concentration and high-efficiency ozone generator is tested according to GB / T18202-2000 "Hygienic Standard for Ozone in Indoor Air" and evaluated according to GB 28232-2020 "Hygienic Requirements for Ozone Disinfectors", reaching the leading level at home and abroad.

[0031] I. Equipment

[0032] 1. Disinfection equipment: Zhongtong brand CF-G-2-1500G ozone generator

[0033] 2. Test instrument: Ozone detector.

[0034] II. Methods

[0035] 1. Inspection standard: GB / T 18202-2000 "Hygienic Standard for Ozone in Indoor Air".

[0036] 2. Test method: The prototype was placed at 30m 3 In a confined space, the equipment was turned on, and the ozone gas flow rate was set to 4.3 Nm / h. The ozone concentration was measured at a height of 1.5 m above the ground. Measurements were taken every 5 minutes, and the average value was recorded. The total testing time was 60 minutes.

[0037] 3. Testing conditions: The ambient temperature was 21.4℃ and the relative humidity was 50%RH.

[0038] III. Results

[0039] Ozone concentration test results

[0040]

[0041] Ozone production was 1509.84 g / h. Detection conclusion: The set ozone gas flow rate was 4.3 Nm³. 3 The average ozone concentration in indoor ambient air was 351.125 mg / L over 1 hour, with an ozone output of 1509.84 g / h. However, the highest concentration of ozone generated by large-scale ozone generators at home and abroad is less than 200 mg / L. For example, the technical requirement for ozone generators for water treatment in the National Standard of the People's Republic of China GB / T 37894-2019 is 180 mg / L.

[0042] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A sustainable process for reusing wastewater from coastal underground brine aquaculture, characterized in that, This process involves a combination of biological treatment, ozone sterilization and oxidation, advanced oxidation, catalytic oxidation, and filtration to treat aquaculture wastewater. Specifically, it includes the following steps: S1. The underground brine is introduced into the aquaculture wastewater conditioning biological treatment tank through a water replenishment pump. At the same time, biological carbon source and denitrifying bacteria are added to the aquaculture wastewater conditioning biological treatment tank to remove TN, TP and COD from the underground brine to form effluent. S2. Under the action of the water pump, the effluent undergoes ozone sterilization and disinfection pre-oxidation, quartz sand filtration, hydroxyl radical oxidation, ozone catalytic oxidation, carbon filtration, softening, primary fine filtration, secondary fine filtration, and ultrafiltration in sequence, and is then divided into two streams. One stream forms concentrated water, which is purified and recycled; the other stream enters a compliant reuse water tank, where high-density, high-dissolved-oxygen purified water is formed, with an oxygen content of 15-25 mg / L. The ozone required in the ozone sterilization and disinfection pre-oxidation, hydroxyl radical oxidation, and ozone catalytic oxidation processes is high-concentration ozone, which is produced through an ozone preparation process. The specific ozone preparation process is as follows: S2-1. The gas produced by the screw air compressor passes through the gas storage tank, refrigerated dryer, purifier, filter, PSA oxygen generator, ozone generator and anti-backflow protection device in sequence to form high-concentration ozone. S2-2, The moisture generated from the gas storage tank, refrigerated dryer, purifier and filter is automatically discharged; the cold water required by the ozone generator is provided by an industrial chiller; S3. The purified water in the compliant reuse water tank passes through RO reverse osmosis and enters the pure water tank. After passing through RO reverse osmosis, the purified water forms concentrated brine, which is used to condense industrial salt. The purified water in the compliant reuse water tank passes through salinity adjustment and enters the makeup water pump. The water in the pure water tank and the salinity-adjusted purified water are combined at the inlet of the makeup water pump and then flow back to the compliant reuse water tank through the makeup water pump. The purified water in the compliant reuse water tank enters the aquaculture workshop through the reuse water pump. The sewage in the aquaculture workshop is discharged into the aquaculture sewage conditioning biochemical tank for recycling. The effluent undergoes a three-stage ozone treatment process: first-stage ozone oxidation via an ozone sterilization and disinfection pre-oxidation unit; second-stage advanced oxidation via a hydroxyl radical oxidation unit; and third-stage catalytic oxidation via an ozone catalytic oxidation unit. A quartz sand filtration step is provided between the primary ozone oxidation and the secondary ozone advanced oxidation step, which is completed by a quartz sand filtration unit; the carbon filtration is completed by a carbon filtration unit; the softening step is completed by a softening unit; the primary and secondary fine filtration steps are completed by a fine filtration unit; and the ultrafiltration step is completed by a fully automatic ultrafiltration unit. The primary, secondary, and ultrafiltration steps are used to filter the effluent, removing small particulate solids, organic matter, and microorganisms from the filtrate, thereby further improving the purification and filtration effect on aquaculture wastewater and forming a qualified filtrate.

2. The sustainable coastal underground brine aquaculture wastewater reuse process according to claim 1, characterized in that, The biocarbon source includes any one of bran, straw, wheat husk, rice husk, and corn cob.

3. The sustainable coastal underground brine aquaculture wastewater reuse process according to claim 1, characterized in that, After being treated by ozone catalytic oxidation, the effluent becomes qualified discharge water that flows into a reuse pond for recycling.

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