KR102029958B1 - Circulating seawater filtration system by the adbanced oxidation process and circulating seawater filtration method using the same - Google Patents

Abstract

The present invention is a raw water tank; A sterilization tank for inputting hydrogen peroxide (H ₂ O ₂ ) and ozone (O ₃ ) to the raw water introduced from the raw water tank (AOP, Advanced Oxidation Process); Neutralization tank for neutralizing by adding hypochlorous acid (NaOCl) to the primary treatment water treated in the sterilization tank; A biological filtration tank for removing nitrogen compounds in the secondary treated water treated in the neutralization tank; And Advanced oxidation treatment seawater circulation filtration system and a seawater circulation filtration method comprising a piping line for forming a circulation loop for supplying the final treated water flowing out of the biofiltration tank to the raw water tank through the circulation pump It is about. The advanced oxidation seawater circulation filtration system and the seawater circulation filtration method using the same of the present invention can effectively remove residual hydrogen peroxide and residual ozone without generating toxic bromate compound when the advanced oxidation treatment process is applied to seawater culture. In addition, the organic water is organically combined with the chemical water treatment process of organic decomposition by organic oxidation and denitrification by biofiltration, and the efficiency of seawater treatment is excellent.

Description

AOP Seawater Circulation Filtration System and Seawater Circulation Filtering Method {CIRCULATING SEAWATER FILTRATION SYSTEM BY THE ADBANCED OXIDATION PROCESS AND CIRCULATING SEAWATER FILTRATION METHOD USING THE SAME}

The present invention relates to an advanced oxidation treatment (AOP) seawater circulation filtration system and a seawater circulation filtration method using the same. More specifically, the advanced oxidation treatment is performed, and residual hydrogen peroxide (H ₂ O ₂ ) and residual ozone during the advanced oxidation treatment are performed. The present invention relates to a seawater circulation filtration system capable of effectively removing (O ₃ ) and a seawater circulation filtration method using the same.

In general, aquaculture farms are able to trap fish and fish them, and by putting a large number of fish in a confined seawater in a confined space, there is an extremely low amount of oxygen dissolved in the water, which limits the activities of fish. Less food can result in low growth or, in severe cases, fish die.

In addition, fish food and excreta accumulate on the bottom to form suspended matters, which severely pollute the water quality and promotes a decrease in oxygen dissolved amount.

As such, the water contained in aquaculture tanks, such as fish farms, which farm various fish, is easily contaminated by ammonia (NH ₃ ), nitrous acid (HNO ₂ ), and food waste of various wastes generated in the process of farming fish.

If the pollution is left unattended, there is a risk that fish may die from various diseases, and if the polluted water is discharged to the outside of the tank as it is, there is a risk of secondary pollution.

As such, a water treatment method using an advanced oxidation process (AOP) has been attempted to purify the water contained in the fish farming tank. The advanced oxidation process uses an oxidizing agent such as ozone or irradiates the oxidizing agent with ultraviolet rays to oxidize organic pollutants in wastewater by generating OH (hydroxy radical), a chemical species having strong sterilization and oxidizing power, as an intermediate product. It is a technology to decompose by means of more advanced water treatment technology developed to decompose hardly decomposable material which is not easily decomposed by a general treatment method or to treat a high concentration of pollutants in a short time.

However, the ozone in the water ponds (O ₃₎ to the case that high applying the oxidation treatment process by, the bromine contained in the sea water (Br ^-) and ozone (O ₃₎ and the reaction bromate with a toxicity (BrO ₃ ^-) compound Formation of the fish can cause a problem of death.

The present inventors have completed the present invention to develop a seawater circulation filtration system that is effective for seawater treatment by decomposing organic substances effectively when performing advanced oxidation treatment on seawater culture, but preventing the production of toxic bromate compounds.

The problem to be solved by the present invention is to provide a highly oxidized seawater circulation filtration system and a seawater circulation filtration method using the same that does not produce a toxic bromate compound when the advanced oxidation treatment process is applied to seawater culture.

Another object of the present invention, ozone (O ₃₎ and hydrogen peroxide (H ₂ O ₂₎ by using the advanced oxidation treatment process is performed after the residual hydrogen peroxide (H ₂ O ₂₎ for removing high oxidation treatment water circulation to the To provide a filtration system and a seawater circulating filtration method using the same.

Another problem to be solved by the present invention is that organic decomposition by the advanced oxidation process and denitrification by biofiltration is excellent, and the physical water treatment process by the dissolved ozone flotation device organically combined contaminated seawater water treatment To provide a highly oxidized seawater circulation filtration system and a seawater circulation filtration method using the same.

One aspect of the invention is a raw water tank; A sterilization tank for inputting hydrogen peroxide (H ₂ O ₂ ) and ozone (O ₃ ) to the raw water introduced from the raw water tank (AOP, Advanced Oxidation Process); A neutralization tank for removing residual hydrogen peroxide (H ₂ O ₂ ) by adding sodium hypochlorite (NaOCl) or sodium hypobromite (NaOBr) to the primary treated water treated by the sterilization tank; A biological filtration tank for removing nitrogen compounds in the secondary treated water treated in the neutralization tank; And a piping line for forming a circulation loop for resupplying the final treated water flowing out of the biofiltration tank to the raw water tank through a circulation pump.

In addition, the hydrogen peroxide (H ₂ O ₂ ) is added to the sterilization tank before the ozone (O ₃ ), the molar ratio (H ₂ O ₂ / O ₃ ) of the hydrogen peroxide and the ozone is added so as to be 0.1 to 0.5, the altitude The oxidation treatment is characterized in that the ozone is decomposed to radical radicals by the following chemical reaction formula 1.

[Chemical Scheme 1]

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In addition, the first treatment water introduced into the neutralization tank is characterized in that the neutralization reaction to remove the residual hydrogen peroxide according to the following chemical reaction formula 2.

[Chemical Scheme 2]

In addition, the neutralization tank is provided with a pressurized flotation device of dissolved ozone floatation (DOF) method, the pressurized flotation device is an ozone generator for supplying ozone gas, ozone gas through the injection nozzle in the lower portion of the neutralization tank. It characterized in that it comprises a spray nozzle unit for injecting, a floating separator for separating the scum floated to the upper portion of the neutralization tank, and a scum collector for collecting the separated scum.

In addition, the ozone gas is characterized in that it is injected into the pressure flotation device in the concentration range of 2.4mg / L to 2.7mg / L.

Another aspect of the present invention relates to a seawater circulation filtration method using the highly oxidized seawater circulation filtration system.

The advanced oxidation treatment seawater circulation filtration system of the present invention and the seawater circulation filtration method using the same do not produce toxic bromate compound when the advanced oxidation treatment process is applied to the seawater culture, and performs the advanced oxidation treatment process using ozone and hydrogen peroxide. Residual hydrogen peroxide and residual ozone can be removed effectively, and the physical water treatment process using dissolved ozone flotation device is organically combined with the chemical water treatment process of organic decomposition by organic oxidation and denitrification by biofiltration. The efficiency is very good.

1 is a flow chart schematically showing a highly oxidized seawater circulation filtration system according to an embodiment of the present invention.
2 is a conceptual diagram schematically showing a highly oxidized seawater circulation filtration system according to an embodiment of the present invention.
3 is a cross-sectional view of a biofiltration tank according to an embodiment of the present invention.
Figure 4 is a flow chart schematically showing a highly oxidized seawater circulation filtration system according to another embodiment of the present invention.
5 is a conceptual diagram schematically showing a highly oxidized seawater circulation filtration system according to another embodiment of the present invention.
Figure 6 (a) shows a front view of the drum screen device according to an embodiment of the present invention, Figure 6 (b) shows a side cross-sectional view of the drum screen device.

Hereinafter, embodiments of the present invention will be described in detail. However, this is presented as an example, by which the present invention is not limited and the present invention is defined only by the scope of the claims to be described later.

1 is a flowchart schematically showing a highly oxidized seawater circulation filtration system according to an embodiment of the present invention, Figure 2 is a conceptual diagram schematically showing a highly oxidized seawater circulation filtration system according to an embodiment of the present invention. 1 and 2, the seawater circulation filtration system 1000 according to an embodiment of the present invention is a raw water tank (100); A sterilization tank 200 for inputting hydrogen peroxide (H ₂ O ₂ ) and ozone (O ₃ ) to the raw water introduced from the raw water tank 100 (AOP, Advanced Oxidation Process); Neutralization tank 400 to neutralize by adding hypochlorous acid (NaOCl) to the first treatment water treated in the sterilization tank (200); And a biological filtration tank 500 for removing nitrogen compounds in the secondary treated water treated by the neutralization tank 400, and the raw water tank through the circulation pump 600 for the final treated water flowing out of the biological filtration tank 500. Characterized in that the pipe line 700 is formed to form a circulation loop for resupply to the.

Raw water stored in the raw water tank 100 is seawater used in the seawater culture of fish, and contains the components of the seawater originally contained, such as sodium (Na), bromine (Br), chlorine (Cl) It includes, and aquatic organisms such as ammonia (NH ₄ ) and microorganisms such as bacteria that are produced according to the fish farming is continuously generated and water treatment is required.

Raw water stored in the raw water tank 100 is introduced into the sterilization tank 200 for the Advanced Oxidation Process (AOP).

The Advanced Oxidation Process (AOP) causes artificially decomposition of ozone under normal temperature and normal pressure to generate highly reactive radicals, and uses organic radicals (OH) to produce organic matter in seawater. It is a process of decomposing and sterilizing bacteria and the like existing in seawater.

In the present invention, hydrogen peroxide (H ₂ O ₂ ) is added as a method for decomposing ozone (O ₃ ). Specifically, hydrogen peroxide (H ₂ O ₂ ) is first introduced into the sterilization tank 200 and then ozone (O ₃ ) is added. At this time, the hydrogen peroxide must be added before the ozone to increase the decomposition efficiency of the ozone to increase the production yield of the radical radicals. The ozone may be introduced in the diffuser type or in the side stream type.

In the advanced oxidation treatment process of the present invention, ozone is decomposed by the following Chemical Reaction Formula 1 to be converted into hydroxyl radical.

[Chemical Scheme 1]

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The concentration ratio (molar ratio) (H ₂ O ₂ / O ₃₎ of hydrogen peroxide and ozone introduced into the sterilization tank 200 may be added so as to be 0.1 to 0.5, preferably 0.25 to 0.35. In the above range, the decomposition effect of organic matter in seawater can be significantly improved, and residual hydrogen peroxide can be minimized.

The primary treatment water treated in the sterilization tank 200 by the advanced oxidation treatment is introduced into the neutralization tank 400.

Sodium hypochlorite (NaOCl) or sodium hypobromite (NaOBr) is introduced into the first treatment water introduced into the neutralization tank 400, and a neutralization reaction is performed to remove residual hydrogen peroxide according to the following Chemical Scheme 2.

[Chemical Scheme 2]

After the neutralization reaction is performed, a scum having a particle diameter of 10 to 60 µm is formed by using a pressure rising apparatus 450 of dissolved ozone floatation (DOF) provided in the neutralization tank 400. It can be removed by floating from the top.

The pressure flotation device is a water purifier that attaches a small bubble having a particle diameter of about 5 to 10 μm to a solid material, floats it on the surface of water, and removes scum that floats on the surface of the water. In the present invention, scum is defined as sludge suspended solids.

Pressurized flotation device 450 according to an embodiment of the present invention is the ozone generator for supplying ozone gas and the injection nozzle unit 451 and the neutralization tank 500 for injecting ozone gas through the injection nozzle in the lower portion of the neutralization tank (500). ) And a scum collecting unit 453 for collecting the scum separated from the flotation separator 452 for separating the scum that has risen to the top. The scum collected by the scum collection unit 453 may be removed by being discharged to the outside.

Some of the final treated water treated in the biofiltration tank 500 is injected into the injection nozzle unit 451 by a pressure pump in the state of mixing ozone gas. According to Henry's law, the solubility of gas dissolved in water increases with increasing pressure, and the ozone-dissolved pressurized water is supersaturated under the high pressure of 4 to 8 kg / cm ² produced by the pressure pump. When the supersaturated pressurized water flows into the neutralization tank under atmospheric pressure through the injection nozzle unit 451, fine bubbles having an average particle diameter of 5 to 10 μm are generated due to a sudden decrease in pressure. The generated bubbles combine with the floating or colloidal particles in the neutralization tank to rise.

In addition, the pH can be increased by removing carbon dioxide (CO ₂ ) in the water according to the aeration of ozone dissolved in the pressurized water, it is possible to control the pH of the water by adjusting the amount of aeration of ozone.

The pressure flotation device 450 can increase the load speed from 400 m 3 / m 2 .day of the standard pressure flotation device to 800 m 3 / m 2 .day of the high speed pressure flotation device, so that the settling load speed of the existing flocculation sedimentation process is 20 m 3 / m. 10 to 20 minutes faster than the existing flocculation sedimentation process, which is 20 to 40 times faster than the methane. There is an advantage that the area and the aggregation time can also be shortened.

The dissolved ozone flotation apparatus of the present invention is a device for generating a pressurized injury and an ozone reaction by supplying ozone gas generated from an ozone generator instead of air.

In one embodiment, the ozone gas is preferably injected into the pressure flotation device in a concentration range of 2.4 mg / L to 2.7 mg / L. When the concentration of ozone exceeds 2.7 mg / L, turbidity and removal efficiency of organic matters may be deteriorated because it acts as a cause of increasing the concentration of fine suspended matter and dissolved organic matter by decomposing suspended organic matter in water. have. When the ozone concentration was 2.7 mg / L, the turbidity of raw water was 93.6%.

In the neutralization tank 400, the second treated water from which scum is removed in a neutralization reaction and dissolved ozone flotation is introduced into the biofiltration tank 500.

3 is a cross-sectional view of a biofiltration tank according to an embodiment of the present invention. Referring to FIG. 3, the biofiltration tank includes a porous filter 51 and a collecting pipe 52. The biofiltration tank 400 may denitrify nitrogen compounds such as ammonia in the secondary treated water.

The porous medium 51 is formed by microorganisms that decompose organic matter therein, and is immersed in the secondary treated water 4 introduced from the neutralization tank to filter the secondary treated water 4. can do. The porous filter 51 may be used as long as the inner surface area has a wide internal surface and can be attached to microorganisms, and examples of such materials may include fibers (geotextiles), foams such as sponges, activated carbon, and the like. .

Looking at the installation method for the collecting pipe 52 according to the material of the porous filter 51, if the porous filter 51 is the same material as the sponge, the plate-shaped sponge wraps around the collecting pipe 52 The winding method may be applied, or in the case of a cylindrical bulk sponge, a method of inserting the collecting pipe 52 by forming an insertion hole into which the collecting pipe 52 may be inserted may be applied. On the other hand, when the porous medium 51 is granular activated carbon, the granular activated carbon may be placed in a pocket made of fiber and installed along the outer circumferential surface of the collecting pipe 52. When the porous media 51 is installed in thickness, the porous media 51 has a cylindrical shape, so that the closer to the center of the porous media 51, the faster the flow rate is. Therefore, when the porous media 51 is designed using data measured in a general column type reactor, In view of this, the diameter of the porous media 51 should be determined.

The collecting pipe 52 is provided in the porous filter 51 and has a plurality of collecting holes 210 formed on the outer circumferential surface thereof, and passes through the porous filter 51. The filtered tertiary treated water 5 flows into the collecting hole 210 and flows inside. Here, the collecting pipe 52 may be inserted or positioned at any position inside the porous media 51, but the porous media 51 is enclosed along an outer circumferential surface or positioned at the center of the porous media 51. Good to do.

The final treated water (5), the water treatment is completed through the biological filtration tank 500 is introduced into the raw water tank (100) through a pipe 700 to form a circulation loop through the circulation pump 600, such a circulating filtration process Through this, raw water can be efficiently and continuously treated.

Hereinafter, a seawater circulation filtration system 1100 according to another embodiment of the present invention will be described with reference to the drawings.

For convenience of description, the same reference numerals are used to designate components having the same construction and operation as the exemplary embodiment, and detailed description thereof will be omitted.

4 is a conceptual diagram schematically showing a seawater circulation filtration system 1100 according to another embodiment of the present invention, Figure 5 is a conceptual diagram schematically showing a seawater circulation filtration system according to another embodiment of the present invention. 4 and 5, the seawater circulation filtration system 1100 according to another embodiment of the present invention is a raw water tank (100); A sterilization tank 200 for inputting hydrogen peroxide (H ₂ O ₂ ) and ozone (O ₃ ) to the raw water introduced from the raw water tank 100 (AOP, Advanced Oxidation Process); Drum screen device 300 for removing the sludge of the first treatment water treated in the sterilization tank 200; Neutralization tank 400 for neutralizing by adding hypochlorous acid (NaOCl) to the secondary treatment water treated by the drum screen device 300; And a biological filtration tank 500 for removing nitrogen compounds in the tertiary treated water treated in the neutralization tank 400, and the raw water tank through the circulating pump 600 for the final treated water discharged from the biological filtration tank 500. Characterized in that the pipe line 700 is formed to form a circulation loop for resupply to the.

Figure 6 (a) shows a front view of the drum screen device 300 according to an embodiment of the present invention, Figure 6 (b) shows a side cross-sectional view of the drum screen device 300.

Referring to FIG. 6, the drum screen device 300 according to an embodiment of the present invention includes a support frame 10, a drum screen 20, a rotary motion device 30, and a drum washing unit 40.

The support frame 10 rotatably supports the drum screen 20. The drum screen 20 has a cylindrical shape and is rotatably supported by the support frame 10 in a horizontally laid state. Both ends of the drum screen 20 are rotatably supported by the support frame 10. The drum screen 20 is filtration is performed as the primary treated water for water purification passes from the outer side of the circumference to the inside and is installed to purify the water quality.

The primary treated water 2 is introduced into the drum screen 20 from the outside and the secondary treated water 3 from which the water quality is purified is discharged toward the end surface of the drum screen 20.

The drum screen 20 has a circumferential portion and is formed in a cylindrical shape formed on both ends of the cylindrical opening, the first end plate 24 for closing one end surface of the filtering net 21, and The second end plate 26 is formed on the other end surface of the filter net 21 and the outlet 27 is formed so that the treated water is discharged. The outlet 27 is connected to the neutralization tank 400.

The filter net 21 can be made using a filter net made of a metal fabric for the purpose of improving strength and durability.

A central shaft 25 for rotatably supporting the drum screen 20 to the support frame 20 may be installed at the center of the first end plate 24.

The outlet 27 is made of a hollow pipe and is installed in the center of the second end plate 26.

The outlet 27 formed of the hollow pipe may be rotatably supported by the support frame 20 together with the central axis 25 of the drum screen 20.

In order to discharge the purified water in the drum screen 20, it is also possible to forcibly discharge it using a pump or the like, and flows naturally to the primary treated water 2 and the secondary treated water 3 by giving flowability (direction). It is also possible.

The drum screen 20 is rotated by using the rotary motion device 30 so that the filtration is made evenly using the entire filtration net 21 forming a circumferential portion.

The rotary motion device 30 directly rotates the drum screen 20 using a motor as a driving source, or rotates the drum screen 20 using a transmission device such as a gear, a belt, a chain, or the like.

The drum screen 20 is attached to the sludge 4 to the outer surface of the filter net 21 by filtering the primary treated water (2) by the filter net 21 while rotating by the rotary motion device (30).

The sludge 4 attached to the filtering net 21 of the drum screen 20 is removed by the drum washing unit 40.

The drum washing unit 40 is provided with a suction port 43 for performing suction at a position close to an upper side of the outer circumferential surface of the drum screen 20 while a part of the outer circumferential surface of the drum screen 20 is locked to the treated water 2. And the sludge 4 introduced as the pollutants 4 attached to the outer circumferential surface of the drum screen 20 flows into the suction port 42 and is collected.

When passing through the drum screen device 300, sludge having a particle diameter of 60 μm or more existing in the primary treated water 2 may be removed.

The seawater circulating filtration system of the present invention does not generate toxic bromate compounds when the advanced oxidation treatment process is applied to seawater culture, and can effectively remove residual hydrogen peroxide (H ₂ O ₂ ) and residual ozone (O ₃ ). .

In addition, the organic material decomposition by the advanced oxidation process and the denitrification by biofiltration is excellent, and the physical water treatment process by the dissolved ozone flotation device has the advantage of organic treatment of contaminated seawater by organic bonding.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments and can be manufactured in various forms, and a person of ordinary skill in the art to which the present invention pertains has the technical idea of the present invention. However, it will be understood that other specific forms may be practiced without changing the essential features. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive.

Claims (6)

Raw water tank;
A sterilization tank for inputting hydrogen peroxide (H ₂ O ₂ ) and ozone (O ₃ ) to the raw water introduced from the raw water tank (AOP, Advanced Oxidation Process);
A neutralization tank for removing residual hydrogen peroxide (H ₂ O ₂ ) by adding sodium hypochlorite (NaOCl) or sodium hypobromite (NaOBr) to the primary treated water treated by the sterilization tank;
A biological filtration tank for removing nitrogen compounds in the secondary treated water treated in the neutralization tank; And
And a piping line for forming a circulation loop for supplying the final treated water flowing out of the biofiltration tank to the raw water tank through a circulation pump.
The neutralization tank is provided with a pressurized flotation device of dissolved ozone floatation (DOF) method,
The pressurization apparatus includes an ozone generator for supplying ozone gas, an injection nozzle unit for injecting ozone gas through the injection nozzle from the lower part of the neutralization tank, a floating separation unit for separating the scum floating above the neutralization tank, and a separated scum Advanced oxidation treatment seawater circulation filtration system comprising a scum collection unit for collecting the.
The method of claim 1,
Hydrogen peroxide (H ₂ O ₂ ) is added to the sterilization tank before ozone (O ₃ ),
The molar ratio (H ₂ O ₂ / O ₃₎ of the hydrogen peroxide and the ozone is added so as to be 0.1 to 0.5,
The advanced oxidation process is a highly oxidized seawater circulating filtration system characterized in that the ozone is decomposed to hydroxyl radicals by the following chemical reaction scheme 1:
[Chemical Scheme 1]

.
The method of claim 1,
The first treatment water introduced into the neutralization tank is a highly oxidized seawater circulation filtration system, characterized in that the neutralization reaction to remove the residual hydrogen peroxide is made according to the following chemical reaction formula 2.
[Chemical Scheme 2]

delete The method of claim 1,
The ozone gas is advanced oxidation treatment seawater circulating filtration system, characterized in that injected to the pressure flotation device in the concentration range of 2.4mg / L to 2.7mg / L.
A seawater circulation filtration method using the highly oxidized seawater circulation filtration system according to any one of claims 1 to 3.

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