Wastewater treatment method and wastewater treatment device

Abstract

To provide a wastewater treatment method and a wastewater treatment device.SOLUTION: A wastewater treatment method and a wastewater treatment device are disclosed. The wastewater treatment method includes the steps of: passing wastewater through a UV reaction tank to generate primary treated water (S10-1); passing the primary treated water through a pH adjustment tank to generate secondary treated water (S10-2); passing the secondary treated water through a first coagulation tank to generate tertiary treated water (S10-3); passing the tertiary treated water through a second coagulation tank to generate quaternary treated water (S10-4); passing the quaternary treated water through an inorganic settling tank to generate quinary treated water and sludge (S10-5); passing the fifth treated water through a biological treatment tank to generate a sixth treated water (S10-6); and passing the sixth treated water through an organic settling tank to generate a seventh treated water (S10-7).SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a wastewater treatment method and a wastewater treatment device, and more particularly to a wastewater treatment method and a wastewater treatment device capable of improving the stability of inorganic matter treatment and the nitrification rate during organic matter treatment. [Background technology]

[0002] In the electronics industry, wastewater containing hydrogen peroxide, organic solvents, and inorganic acids (such as hydrofluoric acid) is generated in wet etching processes. In order to treat wastewater discharged from the electronics industry containing such components, the prior art used a process combining a coagulation and sedimentation process with a biological reaction process. However, when hydrogen peroxide is removed using a hydrogen peroxide remover, oxygen bubbles are generated, and if an excessive amount of oxygen bubbles remain in the wastewater, there is a problem that sludge floats in the settling tank. In addition, the presence of persistent organic matter in the wastewater inhibits the activity of microorganisms, and there is a problem that the nitrification rate is inhibited in the biological reaction process.

[0003] In addition, it is expected that stricter regulations on fluoride concentration in effluent will be stipulated and legalized in the Law on Integrated Management of Environmental Pollution Facilities around 2025. As a result, there is a growing need for a highly efficient fluoride removal process that minimizes the amount of fluoride removal agent injected and minimizes side effects. If an increased amount of fluoride removal agent is injected, not only will the amount of sludge generated increase, and the sludge treatment equipment and its treatment capacity will increase, but the settling speed of the sediment will decrease and the site area of ​​the settling area will increase. As the chlorine (Cl) concentration increases, it will be necessary to change the material of the pipes / pumps to prevent corrosion caused by chlorine, or take measures to minimize the negative impact on the environment. Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to provide a wastewater treatment method capable of improving the stability of inorganic matter treatment and the nitrification rate during organic matter treatment.

[0005] Another problem to be solved by the present invention is to provide a wastewater treatment apparatus capable of improving the stability of inorganic matter treatment and the nitrification rate during organic matter treatment. [Means for solving the problem]

[0006] One aspect of the present invention is A step (S10-1) of passing wastewater through a UV (ultraviolet) reactor to generate primary treated water; (S10-2) passing the primary treated water through a pH adjustment tank to generate secondary treated water; (S10-3) passing the secondary effluent through a first flocculation tank to generate tertiary effluent; (S10-4) passing the tertiary effluent through a second flocculation tank to generate quaternary effluent; (S10-5) passing the fourth effluent through an inorganic settling tank to generate fifth effluent and sludge; A step (S10-6) of passing the fifth effluent through a biological treatment reactor to generate sixth effluent; and (S10-7) passing the sixth effluent through an organic settling tank to produce seventh effluent.

[0007] In step (S10-1), the UV irradiation intensity of the UV reaction tank may be adjusted according to at least one of the hydrogen peroxide concentration in the wastewater, the persistent organic matter concentration in the wastewater, and the persistent organic matter concentration in the treated water discharged from the inorganic settling tank.

[0008] A first chemical may be introduced into the pH adjustment tank, a first chemical and a second chemical may be introduced into the first coagulation tank, and a third chemical may be introduced into the second coagulation tank.

[0009] The first chemical includes hydrated lime, the second chemical includes a fluoride remover, and the third chemical also includes a polymer flocculant.

[0010] The fluoride removing agent may include aluminum chloride (AlCl3), sodium aluminate (NaAlO2), or a combination thereof, and the polymeric flocculant may include anionic polyacrylamide, sodium alginate, sodium polyacrylate, maleic acid copolymer, partial hydrolyzate of polyacrylamide, or a combination thereof.

[0011] The pH of the UV reaction chamber is also 2.0 to 3.0.

[0012] The pH of the pH adjusting tank can be adjusted to a range of 3.5 to 6.0.

[0013] The concentration of the second chemical in the first coagulation tank may be adjusted to 800 to 1,700 ppm.

[0014] The pH of the first flocculation tank may be adjusted to a range of 6.5±0.5.

[0015] The concentration of the third chemical in the second flocculation tank may be adjusted to a range of 3.0±1.0 ppm.

[0016] Another aspect of the present invention is A UV reaction tank configured to irradiate the wastewater with UV (ultraviolet) and generate primary treated water; A pH adjustment tank configured to adjust the pH of the primary treated water and generate secondary treated water; a first flocculation tank configured to partially flocculate the secondary effluent to produce a tertiary effluent; A second flocculation tank configured to add the tertiary effluent and partially flocculate it to generate a quaternary effluent; an inorganic settling tank configured to partially settle the quaternary effluent and generate a quinary effluent and a sludge; A biological treatment reaction tank configured to add the quinary treated water and biologically treat it to produce sixth treated water; and an organic settling tank configured to partially settle the sixth effluent and produce seventh effluent and sludge.

[0017] The pH adjustment tank may be configured to operate at a pH range of 3.5 to 6.0.

[0018] The first coagulation tank may be configured to operate at a fluoride removing agent concentration range of 800 to 1,700 ppm.

[0019] The first flocculation tank may be configured to operate with a pH range of 6.5±0.5.

[0020] The second flocculation tank may be configured to operate with a polymer flocculant concentration range of 3.0±1.0 ppm.

[0021] The wastewater treatment device may further include a UV lamp, a first sensor, a second sensor, a rectifier, a photocatalyst, or a combination thereof, wherein the UV lamp is configured to irradiate UV to the UV reaction tank, the first sensor is configured to measure a hydrogen peroxide concentration in the wastewater, and the second sensor is configured to measure at least one of a concentration of persistent organic matter in the wastewater and a concentration of persistent organic matter in the treated water discharged from the inorganic settling tank, the rectifier is configured to adjust the UV irradiation intensity of the UV lamp based on a signal from at least one of the first sensor and the second sensor, and the photocatalyst is configured to promote decomposition of persistent organic matter in the wastewater when irradiated with UV. Effect of the Invention

[0022] According to an embodiment of the present invention, the wastewater treatment method and apparatus can improve the stability of inorganic wastewater treatment equipment and organic wastewater treatment equipment, as well as enable high-speed treatment to save space (nitrification rate is improved by up to 25%). In addition, the automatic control system can be used to perform proper operation required for removing hydrogen peroxide and difficult-to-decompose organic matter, minimizing operating costs. [Brief description of the drawings]

[0023] [Figure 1] 1 is a schematic diagram illustrating a wastewater treatment method and apparatus according to an embodiment; [Diagram 2] FIG. 2 is a diagram showing a photolysis unit provided in the wastewater treatment device of FIG. 1. [Diagram 3] 1 is a graph showing the change in concentration of residual hydrogen peroxide in treated water depending on the residence time during UV treatment. [Figure 4] 1 is a graph showing the removal rate of persistent organic matter during UV treatment and biological treatment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] Hereinafter, a method for treating wastewater according to an embodiment of the present invention will be described in detail.

[0025] As used herein, "wastewater" means untreated wastewater (i.e., raw water or influent).

[0026] In this specification, "UV (ultraviolet)" refers to electromagnetic waves in the wavelength range of 100 nm to 400 nm.

[0027] In this specification, the term "treated wastewater" refers to wastewater that has been treated at all stages, from which impurities in untreated wastewater have been removed and which contains smaller amounts of impurities than the untreated wastewater.

[0028] In this specification, the term "water to be treated" refers to water that is the subject of treatment at a certain stage, and the water to be treated at each stage has a different treatment rate.

[0029] In this specification, the unit "ppm (parts per million)" means mg / L.

[0030] In addition, in this specification, "front end or front end portion" means a portion or end portion located relatively in the opposite direction to the flow direction of wastewater, and "rear end or rear end portion" means a portion or end portion located relatively in the forward direction of the flow direction of wastewater.

[0031] The wastewater treatment method and apparatus according to an embodiment of the present invention can remove hydrogen peroxide, persistent organic matter, fluorine, phosphorus, suspended solids (SS), total nitrogen (TN), biochemical oxygen demand (BOD), particulate matter, and ionic matter from wastewater.

[0032] A wastewater treatment method according to an embodiment of the present invention includes a step of passing wastewater through a UV reaction tank to produce primary treated water (S10-1), a step of passing the primary treated water through a pH adjustment tank to produce secondary treated water (S10-2), a step of passing the secondary treated water through a first coagulation tank to produce tertiary treated water (S10-3), a step of passing the tertiary treated water through a second coagulation tank to produce quaternary treated water (S10-4), a step of passing the quaternary treated water through an inorganic settling tank to produce fifth treated water and sludge (S10-5), a step of passing the fifth treated water through a biological treatment reactor to produce sixth treated water (S10-6), and a step of passing the sixth treated water through an organic settling tank to produce seventh treated water (S10-7).

[0033] The step (S10-1) decomposes hydrogen peroxide in wastewater by UV irradiation to generate OH radicals, and removes persistent organic matter in wastewater using the generated OH radicals. This can eliminate the concern of sludge floating up due to oxygen bubbles that occurs when hydrogen peroxide is decomposed using a hydrogen peroxide remover as in the conventional technology.

[0034] In addition, the step (S10-1) is carried out at a low pH and does not require the addition of slaked lime, which can reduce concerns about scale formation.

[0035] In addition, in step (S10-1), the UV irradiation intensity of the UV reaction tank may be adjusted according to at least one of the hydrogen peroxide concentration in the wastewater, the persistent organic matter concentration in the wastewater, and the persistent organic matter concentration in the treated water discharged from the inorganic settling tank.

[0036] The pH of the UV reactor is also 2.0-3.0. The pH of such a UV reactor can be determined by the pH of the wastewater.

[0037] The step (S10-2) may serve to remove 95% or more of fluorine and less than 50% of phosphorus from the wastewater.

[0038] A first chemical may be added to the pH adjustment tank.

[0039] The first chemical also includes hydrated lime.

[0040] The pH of the pH adjustment tank may be adjusted to a range of 3.5 to 6.0. If the pH of the pH adjustment tank is within this range, not only can high-quality treated water having low fluorine concentration, phosphorus concentration, chloride ion concentration, organic matter concentration, total nitrogen (TN) and BOD can be obtained, but also the amount of sludge generation can be reduced.

[0041] The steps (S10-3) and (S10-4) may serve to remove 3% or more of fluorine from the water being treated (cumulative removal of 98% or more) and 45% or more of phosphorus (cumulative removal of 95% or more), thereby minimizing the amount of chemicals added and the amount of sludge generated.

[0042] The first chemical and the second chemical may be introduced into the first flocculation tank.

[0043] The second chemical concentration in the first coagulation tank may be adjusted to 800 to 1,700 ppm. When the second chemical concentration in the first coagulation tank is within this range, high-quality treated water having low fluorine concentration, phosphorus concentration, chloride ion concentration, organic matter concentration, total nitrogen (TN) and BOD can be obtained, and sludge generation can be reduced.

[0044] The pH of the first coagulation tank may be adjusted to within a range of 6.5±0.5. If the pH of the first coagulation tank is within this range, not only can high-quality treated water having low fluorine concentration, phosphorus concentration, chloride ion concentration, organic matter concentration, total nitrogen (TN) and BOD can be obtained, but also the amount of sludge generation can be reduced.

[0045] The second chemical also includes a fluoride remover.

[0046] The fluoride remover may also include aluminum chloride (AlCl3), sodium aluminate (NaAlO2), or a combination thereof.

[0047] A third chemical may be added to the second flocculation tank.

[0048] The concentration of the third chemical in the second coagulation tank may be adjusted to a range of 3.0±1.0 ppm. If the concentration of the third chemical in the second coagulation tank is within this range, not only can high-quality treated water having low fluorine concentration, phosphorus concentration, chloride ion concentration, organic matter concentration, total nitrogen (TN) and BOD can be obtained, but also the amount of sludge generation can be reduced.

[0049] The third chemical also includes a polymer flocculant.

[0050] The polymeric flocculant may also include anionic polyacrylamide, sodium alginate, sodium polyacrylate, maleic acid copolymers, partial hydrolysates of polyacrylamide, or combinations thereof.

[0051] The step (S10-5) serves to treat organic matter in the water to cause solid-liquid separation.

[0052] The step (S10-6) serves to remove total nitrogen (TN) and BOD from the treated water using microorganisms.

[0053] The biological treatment reactor may be a reactor implementing an activated sludge process, which is a biological wastewater treatment process, or a reactor implementing a process in which a separation membrane process such as microfiltration or ultrafiltration is combined with the activated sludge process.

[0054] In addition, in the biological treatment reactor in step S10-6, a denitrification reaction as shown in Reaction Scheme 1 below may occur due to denitrifying microorganisms. 2NO3 - +10e - +12H + →N2+6H2O

[0055] The denitrifying microorganisms include Pseudomonas, Bacillus, Spirillum, Hyphomicrobium, Agrobacterium, Acinetobacter, Propionibacterium, Rhizobium, Corynebacterium, Cytophaga, Thiobacillus, Alcaligenes, Pseudomonas fluorescens, P. aeruginosa, P. denitrificans, Alcaligenes sp., Curvibacter delicatus, Acidovorax defluvii, Dokdonella koreensis, Dokdonella koreensis, Flavobacterium limicola, Terrimonas ferruginea, Terrimonas lutea, or combinations thereof.

[0056] Hereinafter, a wastewater treatment apparatus 100 according to an embodiment of the present invention will be described in detail with reference to Figures 1 and 2. Figure 1 is a schematic diagram of a wastewater treatment method and apparatus 100 according to an embodiment of the present invention, and Figure 2 is a diagram of a photolysis unit provided in the wastewater treatment apparatus 100 of Figure 1.

[0057] Referring to FIG. 1, a wastewater treatment apparatus 100 according to one embodiment of the present invention includes a UV reaction tank 110, a pH adjustment tank 120, a first coagulation tank 130, a second coagulation tank 140, an inorganic settling tank 150, a biological treatment reaction tank 160 and an organic settling tank 170.

[0058] The UV reactor 110 may be configured to irradiate the wastewater WW with UV light to produce primary treated water.

[0059] Also, referring to FIG. 2 together with FIG. 1, the wastewater treatment device 100 further includes a photolysis unit, such as a UV lamp ULP, a first sensor S1, a second sensor S2, a rectifier RTF, a photocatalyst BPC, or a combination thereof.

[0060] The UV lamp ULP can be configured to irradiate the UV reaction chamber 110 with UV light.

[0061] The first sensor S1 may be configured to measure the hydrogen peroxide concentration in the wastewater WW.

[0062] The second sensor S2 can be configured to measure at least one of the concentration of persistent organic matter in the wastewater WW and the concentration of persistent organic matter in the treated water TW5 discharged from the inorganic settling tank 150.

[0063] The rectifier RTF may be configured to adjust the UV irradiation intensity of the UV lamp ULP according to a signal of at least one of the first sensor S1 and the second sensor S2.

[0064] The photocatalytic BPC may be configured to accelerate the decomposition of persistent organic matter in the wastewater WW when irradiated with UV light. For example, the photocatalytic BPC may be used when no hydrogen peroxide is present in the wastewater WW or when it is present in negligible amounts. Such photocatalytic BPCs may also be fabricated in a baffle shape.

[0065] The pH adjustment tank 120 may be configured to operate within a pH range of 3.5 to 6.0. If the pH adjustment tank 120 is configured to operate within this pH range, not only can high-quality treated water having low fluorine concentration, phosphorus concentration, chloride ion concentration, organic matter concentration, total nitrogen (TN) and BOD can be obtained, but also the amount of sludge generation can be reduced.

[0066] The first coagulation tank 130 may be configured to operate at a fluoride removing agent concentration range of 800 to 1,700 ppm. If the first coagulation tank 130 is configured to operate at this fluoride removing agent concentration range, it is possible to obtain high-quality treated water having low fluoride concentration, phosphorus concentration, chloride ion concentration, organic matter concentration, total nitrogen (TN) and BOD, as well as to reduce the amount of sludge generation.

[0067] In addition, the first coagulation tank 130 may be configured to operate within a pH range of 6.5±0.5. If the first coagulation tank 130 is configured to operate within this pH range, not only can high-quality treated water with low fluorine concentration, phosphorus concentration, chloride ion concentration, organic matter concentration, total nitrogen (TN) and BOD can be obtained, but also the amount of sludge generated can be reduced.

[0068] The second coagulation tank 140 may be configured to operate with a polymer coagulant concentration range of 3.0±1.0 ppm. If the second coagulation tank 140 is configured to operate with this polymer coagulant concentration range, not only can high-quality treated water with low fluorine concentration, phosphorus concentration, chloride ion concentration, organic matter concentration, total nitrogen (TN) and BOD can be obtained, but also the amount of sludge generation can be reduced.

[0069] The wastewater treatment method and apparatus according to an embodiment of the present invention having the above-mentioned configuration can reduce the total amount of chemicals used by 75% by weight, reduce the chloride ion concentration by 28%, increase the nitrogen removal rate by 25%, reduce the site area by 9.7%, and reduce the amount of sludge generated, compared to the prior art.

[0070] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to such examples.

[0071] Example: Making a device A wastewater treatment device having the configuration shown in FIG. 1 was fabricated.

[0072] The wastewater treatment device prepared as described above is composed of a UV reaction tank, a pH adjustment tank, a first coagulation tank, a second coagulation tank, an inorganic settling tank, a biological treatment reaction tank and an organic settling tank.

[0073] Example 1: Operation of wastewater treatment equipment The wastewater used was a semiconductor process wastewater having a pH of 2.5, a fluoride ion concentration (F) of 568 ppm, a chloride ion concentration (Cl) of 50 ppm, a PO4-P of 200 ppm, an organic matter concentration of 400 ppm, a total nitrogen (TN) concentration of 400 ppm, and a BOD of 700 ppm. The pH adjustment tank was charged with slaked lime, the first coagulation tank was charged with slaked lime and aluminum chloride (AlCl3), and the second coagulation tank was charged with anionic polyacrylamide. The amount of slaked lime charged to the pH adjustment tank was such that the pH (R2-pH) of the pH adjustment tank was maintained at 5.0. The amount of aluminum chloride (AlCl3) charged to the first coagulation tank was such that the aluminum chloride (AlCl3) concentration (R3-C2) of the first coagulation tank was 1,200 ppm. The amount of slaked lime added to the first coagulation tank is such that the pH (R3-pH) of the first coagulation tank is maintained at 6.5. The amount of anionic polyacrylamide added to the second coagulation tank is such that the concentration of anionic polyacrylamide (R4-C3) in the second coagulation tank is 3 ppm.

[0074] Example 2: Operation of wastewater treatment equipment The wastewater treatment device was operated in the same manner as in Example 1, except that the amount of slaked lime added to the first coagulation tank was changed to an amount such that the pH (R2-pH) of the pH adjustment tank was maintained at 3.5.

[0075] Example 3: Operation of wastewater treatment equipment The wastewater treatment device was operated in the same manner as in Example 1, except that the amount of slaked lime added to the first coagulation tank was changed to an amount such that the pH (R2-pH) of the pH adjustment tank was maintained at 6.0.

[0076] Example 4: Operation of wastewater treatment equipment The wastewater treatment device was operated in the same manner as in Example 1, except that the content of aluminum chloride (AlCl3) introduced into the first coagulation tank was changed to an amount such that the aluminum chloride (AlCl3) concentration (R3-C2) in the first coagulation tank was 800 ppm.

[0077] Example 5: Operation of wastewater treatment equipment The wastewater treatment device was operated in the same manner as in Example 1, except that the content of aluminum chloride (AlCl3) introduced into the first coagulation tank was changed to an amount such that the aluminum chloride (AlCl3) concentration (R3-C2) in the first coagulation tank became 1,700 ppm.

[0078] Reference Example 1: Operation of wastewater treatment equipment The wastewater treatment device was operated in the same manner as in Example 1, except that the amount of slaked lime added to the first coagulation tank was changed to an amount such that the pH (R2-pH) of the pH adjustment tank was maintained at 3.0.

[0079] Reference Example 2: Operation of wastewater treatment equipment The wastewater treatment device was operated in the same manner as in Example 1, except that the amount of slaked lime added to the first coagulation tank was changed to an amount such that the pH (R2-pH) of the pH adjustment tank was maintained at 6.5.

[0080] Reference Example 3: Operation of wastewater treatment equipment The wastewater treatment device was operated in the same manner as in Example 1, except that the content of aluminum chloride (AlCl3) introduced into the first coagulation tank was changed to an amount such that the aluminum chloride (AlCl3) concentration (R3-C2) in the first coagulation tank was 700 ppm.

[0081] Reference Example 4: Operation of wastewater treatment equipment The wastewater treatment device was operated in the same manner as in Example 1, except that the content of aluminum chloride (AlCl3) introduced into the first coagulation tank was changed to an amount such that the aluminum chloride (AlCl3) concentration (R3-C2) in the first coagulation tank was 1,800 ppm.

[0082] Comparative Example 1: Operation of wastewater treatment equipment The wastewater treatment device was operated in the same manner as in Example 1, except that the UV reaction tank was replaced with a hydrogen peroxide removal tank and the amount of hydrogen peroxide remover (catalase) added to the hydrogen peroxide removal tank was changed so that the concentration of the hydrogen peroxide remover (catalase) in the hydrogen peroxide removal tank was 500 ppm.

[0083] Comparative Example 2: Operation of wastewater treatment equipment The wastewater treatment device was operated in the same manner as in Example 2, except that the UV reaction tank was replaced with a hydrogen peroxide removal tank and the amount of hydrogen peroxide remover (catalase) added to the hydrogen peroxide removal tank was changed to an amount such that the concentration of the hydrogen peroxide remover (catalase) in the hydrogen peroxide removal tank was 500 ppm.

[0084] Comparative Example 3: Operation of wastewater treatment equipment The wastewater treatment device was operated in the same manner as in Example 3, except that the UV reaction tank was replaced with a hydrogen peroxide removal tank and the amount of hydrogen peroxide remover (catalase) added to the hydrogen peroxide removal tank was changed to an amount such that the concentration of the hydrogen peroxide remover (catalase) in the hydrogen peroxide removal tank was 500 ppm.

[0085] Comparative Example 4: Operation of wastewater treatment equipment The wastewater treatment device was operated in the same manner as in Example 4, except that the UV reaction tank was replaced with a hydrogen peroxide removal tank and the amount of hydrogen peroxide remover (catalase) added to the hydrogen peroxide removal tank was changed so that the concentration of the hydrogen peroxide remover (catalase) in the hydrogen peroxide removal tank was 500 ppm.

[0086] Comparative Example 5: Operation of wastewater treatment equipment The wastewater treatment device was operated in the same manner as in Example 5, except that the UV reaction tank was replaced with a hydrogen peroxide removal tank and the amount of hydrogen peroxide remover (catalase) added to the hydrogen peroxide removal tank was changed to an amount such that the concentration of the hydrogen peroxide remover (catalase) in the hydrogen peroxide removal tank was 500 ppm.

[0087] The operating conditions (pH, amount of chemicals charged, and type of chemicals) of the wastewater treatment devices in Examples 1 to 5, Reference Examples 1 to 4, and Comparative Examples 1 to 5 are summarized and shown in Table 1 below. [Table 1]

[0088] Evaluation example 1: Measurement of changes in residual hydrogen peroxide concentration in treated water due to residence time during UV treatment The change in the concentration of residual hydrogen peroxide in the treated water depending on the residence time during UV treatment in the UV reaction tank was measured, and the results are shown in the graph in Figure 3. At this time, the UV irradiation amount was 45 W / m2, and only one UV lamp was used. Referring to FIG. 3, it is shown that when the residence time is 20 minutes, the hydrogen peroxide removal rate is about 73%.

[0089] Evaluation example 2: Removal rate of persistent organic matter during UV treatment and biological treatment The removal rates of persistent organic matter during UV treatment in the UV reaction tank and during biological treatment in the biological treatment reaction tank were measured using LC-OCD (liquid chromatography-organic carbon detector), and the results are shown in Figure 4.

[0090] In Figure 4, (a) is the peak of wastewater (i.e., raw water), (b) is the peak of UV-treated water on the first day, (c) is the peak of biologically treated water on the first day, (d) is the peak of UV-treated water on the second day, and (e) is the peak of biologically treated water on the second day.

[0091] Referring to FIG. 4, it was shown that hardly any recalcitrant organic matter was removed during biological treatment, whereas 100% of the recalcitrant organic matter that inhibits nitrification was removed during UV treatment when the residence time was 20 minutes.

[0092] Evaluation example 3: Performance evaluation of wastewater treatment equipment The quality of the final treated water (i.e., the treated water discharged from the organic settling tank) obtained by operating the wastewater treatment devices of the above-mentioned Examples 1 to 5, Reference Examples 1 to 4, and Comparative Examples 1 to 5 was evaluated, and the results are shown in the following Table 2. In the following Table 2, "SS" is an abbreviation for "suspended solid" and "NM" is an abbreviation for "not measured." [Table 2]

[0093] Referring to Table 2, it was shown that the wastewater treatment devices of Examples 1 to 5 were superior in the quality of the final treated water compared to the wastewater treatment devices of Reference Examples 1 to 4 and Comparative Examples 1 to 5.

[0094] Although the present invention has been described with reference to the drawings and embodiments, they are merely illustrative, and a person skilled in the art will understand that various modifications and equivalent embodiments are possible therefrom. Therefore, the true technical scope of the present invention is defined by the technical ideas of the claims. [Explanation of symbols]

[0095] 100 Wastewater treatment equipment 110 UV Reactor 120 pH adjustment tank 130 1st flocculation tank 140 Second flocculation tank 150 Inorganic Sedimentation Tank 160 Biological treatment reactor 170 Organic Settling Tank BPC Photocatalyst C1, C2, C3 drugs RTF rectifier TW5, TW7 treated water ULP UV Lamp WW Wastewater

Claims

1. A step (S10-1) of passing wastewater through a UV (ultraviolet) reactor to generate primary treated water; (S10-2) passing the primary treated water through a pH adjustment tank to generate secondary treated water; (S10-3) passing the secondary effluent through a first flocculation tank to generate tertiary effluent; (S10-4) passing the tertiary effluent through a second flocculation tank to generate quaternary effluent; (S10-5) passing the fourth effluent through an inorganic settling tank to generate fifth effluent and sludge; A step (S10-6) of passing the fifth effluent through a biological treatment reactor to generate sixth effluent; and (S10-7) passing the sixth effluent through an organic settling tank to produce a seventh effluent.

2. 2. The wastewater treatment method of claim 1, wherein in step (S10-1), the UV irradiation intensity of the UV reaction tank is adjusted according to at least one of a hydrogen peroxide concentration in the wastewater, a persistent organic matter concentration in the wastewater, and a persistent organic matter concentration in the treated water discharged from the inorganic settling tank.

3. 2. The wastewater treatment method according to claim 1, wherein a first chemical is fed to the pH adjustment tank, a first chemical and a second chemical are fed to the first coagulation tank, and a third chemical is fed to the second coagulation tank.

4. The wastewater treatment method according to claim 3 , wherein the first chemical comprises hydrated lime, the second chemical comprises a fluoride removing agent, and the third chemical comprises a polymer flocculant.

5. The fluorine remover is aluminum chloride (AlCl ３ ), sodium aluminate (NaAlO ２ 5. The wastewater treatment method of claim 4, wherein the polymeric flocculant comprises anionic polyacrylamide, sodium alginate, sodium polyacrylate, maleic acid copolymer, partial hydrolyzate of polyacrylamide, or a combination thereof.

6. The wastewater treatment method according to claim 1, wherein the pH of the UV reaction tank is 2.0 to 3.

0.

7. The wastewater treatment method according to claim 6, wherein the pH of the pH adjustment tank is adjusted to a range of 3.5 to 6.

0.

8. The wastewater treatment method according to claim 7, wherein the second chemical concentration in the first flocculation tank is adjusted to 800 to 1,700 ppm.

9. 9. The wastewater treatment method according to claim 8, wherein the pH of the first flocculation tank is adjusted to a range of 6.5±0.

5.

10. The wastewater treatment method according to claim 9 , wherein the concentration of the third chemical in the second flocculation tank is adjusted to a range of 3.0±1.0 ppm.

11. A UV reaction tank configured to irradiate wastewater with UV (ultraviolet) to generate primary treated water; A pH adjustment tank configured to adjust the pH of the primary treated water and generate secondary treated water; a first flocculation tank configured to partially flocculate the secondary effluent to produce a tertiary effluent; a second flocculation tank configured to add the tertiary effluent and partially flocculate it to produce a quaternary effluent; an inorganic settling tank configured to partially settle the quaternary effluent and generate a quinary effluent and a sludge; A biological treatment reaction tank configured to add the quinary treated water and biologically treat it to produce sixth treated water; an organic settling tank configured to partially settle the sixth effluent and produce a seventh effluent and a sludge.

12. 12. The wastewater treatment apparatus of claim 11, wherein the pH adjustment tank is configured to operate with a pH range of 3.5 to 6.

0.

13. 13. The wastewater treatment system of claim 12, wherein the first coagulation tank is configured to operate with a fluoride removing agent concentration range of 800 to 1,700 ppm.

14. 14. The wastewater treatment system of claim 13, wherein the first flocculation tank is configured to operate with a pH range of 6.5±0.

5.

15. 15. The wastewater treatment apparatus of claim 14, wherein the second flocculation tank is configured to operate with a polymer flocculant concentration range of 3.0±1.0 ppm.

16. 12. The wastewater treatment device according to claim 11, further comprising a UV lamp, a first sensor, a second sensor, a rectifier, a photocatalyst, or a combination thereof, wherein the UV lamp is configured to irradiate the UV reaction tank with UV, the first sensor is configured to measure a hydrogen peroxide concentration in the wastewater, and the second sensor is configured to measure at least one of a concentration of a persistent organic matter in the wastewater and a concentration of a persistent organic matter in the treated water discharged from the inorganic settling tank, the rectifier is configured to adjust an irradiation intensity of UV from the UV lamp based on a signal from at least one of the first sensor and the second sensor, and the photocatalyst is configured to promote decomposition of the persistent organic matter in the wastewater when irradiated with UV.

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