Wastewater treatment method and wastewater treatment device

Abstract

The invention discloses a wastewater treatment method and a wastewater treatment device. The disclosed wastewater treatment method comprises the following steps: step S10-1, enabling wastewater to pass through a UV reaction tank to generate primary treatment water; a step S10-2 of passing the primary treated water through a pH adjustment tank to generate secondary treated water; a step S10-3 of passing the secondary treated water through a first coagulating basin to generate tertiary treated water; a step S10-4 of passing the tertiary treated water through a second coagulating basin to generate quaternary treated water; a step S10-5 of passing the fourth-stage treated water through an inorganic sedimentation tank to generate fifth-stage treated water and sludge; a step S10-6 of passing the fifth-stage treated water through a biological treatment reaction tank to generate sixth-stage treated water; and a step S10-7 of passing the sixth-stage treated water through an organic sedimentation tank to generate seventh-stage treated water.

Description

Technical Field

[0001] Disclosed are a wastewater treatment method and a wastewater treatment device. More specifically, disclosed are a wastewater treatment method and a wastewater treatment device, which can improve the stability of treating inorganic substances and the nitrification rate when treating organic substances. Background Art

[0002] In the electronics industry, wastewater including hydrogen peroxide, organic solvents and inorganic acids (such as fluoric acid) is generated in the wet etching process. In order to treat the wastewater containing these components discharged in the electronics industry, the prior art adopts a process combining a coagulation sedimentation process and a biological reaction process. However, when a hydrogen peroxide remover is used to remove hydrogen peroxide, oxygen bubbles are generated. If there are excessive oxygen bubbles remaining in the wastewater, there is a problem that the sludge in the sedimentation tank will rise. In addition, due to the presence of refractory organic matter in the wastewater, the activity of microorganisms is inhibited, so there is a problem of a decrease in the nitrification rate in the biological reaction process.

[0003] At the same time, it is expected that the "Law on Comprehensive Management of Environmental Pollution Facilities" will strengthen and stipulate the regulation of fluorine concentration in discharged water around 2025, and legislation is expected. Therefore, the demand for efficient fluorine removal processes that minimize the injection amount of defluorinating agents and their side effects is increasing. When the injection amount of defluorinating agents increases, not only does the amount of sludge generated increase, resulting in an increase in sludge treatment equipment and treatment capacity, but the sedimentation rate of the sediment decreases, resulting in an increase in the site area of ​​the sedimentation tank, and the chlorine (Cl) concentration also increases, so in order to prevent corrosion caused by chlorine, it is necessary to change the material of the pipe / pump or take measures to minimize the negative impact on the environment. Summary of the invention

[0004] According to one embodiment of the present invention, a wastewater treatment method is provided, which can improve the stability of treating inorganic substances and the nitrification rate when treating organic substances.

[0005] According to another embodiment of the present invention, there is provided a wastewater treatment device which can improve the stability of treating inorganic substances and the nitrification rate when treating organic substances.

[0006] One aspect of the present invention provides a wastewater treatment method, which comprises the following steps:

[0007] The wastewater is passed through a UV reaction tank to generate primary treated water S10-1;

[0008] Passing the primary treated water through a pH adjustment tank to generate secondary treated water S10-2;

[0009] Passing the secondary treated water through a first coagulation tank to generate tertiary treated water S10-3;

[0010] Passing the tertiary treated water through a second coagulation tank to generate quaternary treated water S10-4;

[0011] Passing the quaternary treated water through an inorganic sedimentation tank to generate quinary treated water and sludge S10-5;

[0012] Passing the five-stage treated water through a biological treatment reaction tank to generate six-stage treated water S10-6; and

[0013] The sixth-stage treated water is passed through an organic sedimentation tank to generate seventh-stage treated water S10-7.

[0014] In the step S10-1, the UV irradiation intensity of the UV reaction tank can be adjusted according to at least one of the concentration of hydrogen peroxide in the wastewater, the concentration of refractory organic matter in the wastewater, and the concentration of refractory organic matter in the treated water discharged from the inorganic precipitation tank.

[0015] A first chemical may be put into the pH adjustment tank, a first chemical and a second chemical may be put into the first coagulation tank, and a third chemical may be put into the second coagulation tank.

[0016] The first chemical may include slaked lime, the second chemical may include a defluoridating agent, and the third chemical may include a polymer coagulant.

[0017] The defluoridating agent may include aluminum chloride (AlCl 3 ), sodium aluminate (NaAlO 2 ), or a combination thereof, and the polymer coagulant may include anionic polyacrylamide, sodium alginate, sodium polyacrylate, maleate copolymer, partial hydrolyzate of polyacrylamide, or a combination thereof.

[0018] The pH of the UV reaction cell may be 2.0 to 3.0.

[0019] The pH of the pH adjustment tank can be adjusted within the range of 3.5 to 6.0.

[0020] The concentration of the second chemical in the first coagulation tank may be adjusted within a range of 800 ppm to 1,700 ppm.

[0021] The pH of the first coagulation tank can be adjusted within the range of 6.5±0.5.

[0022] The concentration of the third chemical in the second coagulation tank can be adjusted within the range of 3.0 ppm±1.0 ppm.

[0023] Another aspect of the present invention provides a wastewater treatment device, comprising:

[0024] A UV reaction tank configured to generate primary treated water by irradiating UV into wastewater;

[0025] a pH adjustment tank configured to generate secondary treated water by adjusting the pH of the primary treated water;

[0026] a first coagulation tank configured to generate tertiary treated water by partially coagulating the secondary treated water;

[0027] a second coagulation tank configured to generate quaternary treated water by further partially coagulating the tertiary treated water;

[0028] an inorganic sedimentation tank configured to generate fifth-stage treated water and sludge by partially sedimentating the fourth-stage treated water;

[0029] a biological treatment reaction tank configured to generate sixth-stage treated water by further biologically treating the fifth-stage treated water; and

[0030] The organic sedimentation tank is configured to generate seventh-stage treated water and sludge by partially sedimentating the sixth-stage treated water.

[0031] The pH adjustment cell may be configured to operate within a pH range of 3.5 to 6.0.

[0032] The first coagulation tank may be configured to operate within a defluorination agent concentration range of 800 ppm to 1,700 ppm.

[0033] The first coagulation tank may be configured to operate within a pH range of 6.5±0.5.

[0034] The second coagulation tank may be configured to operate within a polymer coagulant concentration range of 3.0±1.0 ppm.

[0035] 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 into the UV reaction tank, the first sensor may be configured to measure the concentration of hydrogen peroxide in the wastewater, the second sensor may be configured to measure at least one of the concentration of difficult-to-degrade organic matter in the wastewater and the concentration of difficult-to-degrade organic matter in the treated water discharged from the inorganic precipitation tank, the rectifier may be configured to adjust the UV irradiation intensity of the UV lamp according to a signal of at least one of the first sensor and the second sensor, and the photocatalyst may be configured to promote the decomposition of difficult-to-degrade organic matter in the wastewater when UV irradiated. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 The figure schematically shows a wastewater treatment method and apparatus according to one embodiment of the present invention.

[0037] Figure 2 To show the installation Figure 1 Diagram of the photolysis unit of a wastewater treatment plant.

[0038] Figure 3 The graph shows the change in concentration of residual hydrogen peroxide in treated water according to the residence time during UV treatment.

[0039] Figure 4 It is a graph showing the removal rate of difficult-to-degrade organic matter during UV treatment and biological treatment.

[0040] Description of Reference Numerals

[0041] 100: Wastewater treatment plant

[0042] 110: UV reaction pool

[0043] 120: pH adjustment tank

[0044] 130: First coagulation tank

[0045] 140: Second coagulation tank

[0046] 150: Inorganic sedimentation tank

[0047] 160: Biological treatment reactor

[0048] 170: Organic sedimentation tank

[0049] WW: Wastewater

[0050] TW5, TW7: Treated water

[0051] C1 to C3: Pharmaceuticals

[0052] RTF: Rectifier

[0053] ULP: UV light

[0054] BPC: Photocatalyst DETAILED DESCRIPTION

[0055] Hereinafter, a wastewater treatment method according to an embodiment of the present invention will be described in detail.

[0056] In this specification, "wastewater" refers to untreated wastewater (ie, raw water or influent water).

[0057] In addition, in this specification, "ultraviolet (UV)" refers to electromagnetic waves in the wavelength range of 100 nm to 400 nm.

[0058] In addition, in this specification, "treated water" refers to wastewater that has been subjected to various stages of treatment, in which impurities in untreated wastewater have been removed, so that it contains less impurities than the untreated wastewater.

[0059] In addition, in this specification, "water to be treated" refers to water to be treated in a certain step, and the water to be treated in each step has a different treatment rate.

[0060] In addition, in this specification, the unit "ppm (parts per million)" means mg / L.

[0061] In addition, in this specification, the "front end or front end" refers to the part or end located in the opposite direction to the flow direction of the wastewater, and the "rear end or rear end" refers to the part or end located in the forward direction of the flow direction of the wastewater.

[0062] A wastewater treatment method and apparatus according to an embodiment of the present invention can remove hydrogen peroxide, refractory organic matter, fluorine, phosphorus, suspended solids (SS), total nitrogen (TN), biochemical oxygen demand (BOD), particulate matter and ionic matter in wastewater.

[0063] The wastewater treatment method according to one embodiment of the present invention includes: step S10-1 of passing the wastewater through a UV reaction tank to generate primary treated water; step S10-2 of passing the primary treated water through a pH adjustment tank to generate secondary treated water; step S10-3 of passing the secondary treated water through a first coagulation tank to generate tertiary treated water; step S10-4 of passing the tertiary treated water through a second coagulation tank to generate quaternary treated water; step S10-5 of passing the quaternary treated water through an inorganic sedimentation tank to generate fifth treated water and sludge; step S10-6 of passing the fifth treated water through a biological treatment reaction tank to generate sixth treated water; and step S10-7 of passing the sixth treated water through an organic sedimentation tank to generate seventh treated water.

[0064] In the step S10-1, the hydrogen peroxide in the wastewater is decomposed by UV irradiation to generate OH radicals, and the difficult-to-degrade organic matter in the wastewater is removed by using the generated OH radicals, and the concern that sludge will rise due to oxygen bubbles generated when hydrogen peroxide is decomposed by a hydrogen peroxide remover as in the prior art can be eliminated.

[0065] In addition, the step S10-1 is operated at a low pH and no slaked lime is added, thereby reducing the risk of scaling.

[0066] In addition, in step S10-1, the UV irradiation intensity of the UV reaction tank can be adjusted according to at least one of the concentration of hydrogen peroxide in the wastewater, the concentration of recalcitrant organic matter in the wastewater, and the concentration of recalcitrant organic matter in the treated water discharged from the inorganic precipitation tank.

[0067] The pH of the UV reaction tank can be 2.0 to 3.0. The pH of such a UV reaction tank can be determined by the pH of the wastewater.

[0068] The step S10-2 can remove 95% or more of fluorine in the wastewater and remove less than 50% of phosphorus.

[0069] The first chemical may be put into the pH adjustment tank.

[0070] The first chemical may include slaked lime.

[0071] The pH of the pH adjustment tank can be adjusted within the range of 3.5 to 6.0. When the pH of the pH adjustment tank is within the range, not only can high-quality treated water with low fluoride concentration, phosphorus concentration, chloride ion concentration, organic matter concentration, total nitrogen (TN), and BOD be obtained, but also the amount of sludge generated can be reduced.

[0072] Step S10-3 and step S10-4 can further remove 3% or more of fluorine in the water to be treated (cumulative removal equal to or more than 98%), and further remove 45% or more of phosphorus (cumulative removal equal to or more than 95%), and minimize the amount of chemical input and sludge generated.

[0073] The first chemical and the second chemical may be put into the first coagulation tank.

[0074] The concentration of the second chemical in the first coagulation tank can be adjusted between 800ppm and 1,700ppm. When the concentration of the second chemical in the first coagulation tank is within the above range, not only can high-quality treated water with low fluoride concentration, phosphorus concentration, chloride ion concentration, organic matter concentration, total nitrogen (TN), and BOD be obtained, but also the amount of sludge generated can be reduced.

[0075] The pH of the first coagulation tank can be adjusted within the range of 6.5±0.5. When the pH of the first coagulation tank is within the range, not only can high-quality treated water with low fluoride concentration, phosphorus concentration, chloride ion concentration, organic matter concentration, total nitrogen (TN), and BOD be obtained, but also the amount of sludge generated can be reduced.

[0076] The second chemical may include a defluoridating agent.

[0077] The defluorination agent may include aluminum chloride (AlCl 3 ), sodium aluminate (NaAlO 2 ), or a combination thereof.

[0078] A third drug may be put into the second coagulation tank.

[0079] The concentration of the third chemical in the second coagulation tank can be adjusted within the range of 3.0ppm±1.0ppm. When the concentration of the third chemical in the second coagulation tank is within the 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 be obtained, but also the amount of sludge generated can be reduced.

[0080] The third drug may include a polymer coagulant.

[0081] The polymer coagulant may include anionic polyacrylamide, sodium alginate, sodium polyacrylate, maleate copolymer, partial hydrolyzate of polyacrylamide, or a combination thereof.

[0082] The step S10-5 is used to treat organic matter in the water to be treated and allow solid-liquid separation to occur.

[0083] The step S10-6 removes total nitrogen (TN) and BOD in the water to be treated by using microorganisms.

[0084] The biological treatment reaction tank may be a reactor that implements an activated sludge process as a biological wastewater treatment process, or may be a reactor that implements a process combining a separation membrane process such as microfiltration or ultrafiltration and an activated sludge process.

[0085] In addition, in the biological treatment reaction tank of step S10-6, a denitrification reaction as shown in the following reaction formula 1 may occur by denitrifying microorganisms.

[0086] [Reaction 1]

[0087] 2NO3 - +10e - +12H + →N2+6H2O

[0088] The denitrifying microorganisms may include Pseudomonas, Bacillus, Spirillum, Hyphomicrobium, Agrobacterium, Acinetobacter, Propionibacterium, Rhizobium, Corynebacterium, Cytophaga, Thiobacillus, Alcaligenes, Pseudomonas fluorescens, P. Aeruginosa, Pseudomonas denitrificans, Alcaligenes sp., Curvibacterdelicatus, Acidovorax defluvii, Dokdonella koreensis, Flavobacterium limicola), Terrimonas ferruginea, Terrimonas lutea, or a combination thereof.

[0089] In the following, see Figure 1 and Figure 2 , a wastewater treatment device 100 according to an embodiment of the present invention will be described in detail. Figure 1 To schematically illustrate a wastewater treatment method and apparatus 100 according to an embodiment of the present invention, Figure 2 To show the installation Figure 1 Diagram of a photolysis unit of a wastewater treatment plant 100.

[0090] See also Figure 1 According to an embodiment of the present invention, a wastewater treatment device 100 may include a UV reaction tank 110, a pH adjustment tank 120, a first coagulation tank 130, a second coagulation tank 140, an inorganic precipitation tank 150, a biological treatment reaction tank 160 and an organic precipitation tank 170.

[0091] The UV reaction tank 110 may be configured to generate primary treated water by irradiating UV to the wastewater WW.

[0092] Also, see Figure 1 and Figure 2The wastewater treatment device 100 may further include 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.

[0093] The UV lamp ULP may be configured to irradiate UV into the UV reaction cell 110 .

[0094] The first sensor S1 may be designed to measure the concentration of hydrogen peroxide in the wastewater WW.

[0095] The second sensor S2 may be configured to measure at least one of a concentration of the hardly degradable organic matter in the wastewater WW and a concentration of the hardly degradable organic matter in the treated water TW5 discharged from the inorganic precipitation tank 150 .

[0096] 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.

[0097] The photocatalyst BPC can be configured to promote the decomposition of refractory organic matter in the wastewater WW when UV irradiation occurs. For example, when hydrogen peroxide is not present in the wastewater WW, or the amount present is negligible, the photocatalyst BPC can be used. Such a photocatalyst BPC can be made in the form of a baffle.

[0098] The first chemical C1 can be put into the pH adjustment tank 120. The pH adjustment tank 120 can be configured to operate within a pH range of 3.5 to 6.0. When the pH adjustment tank 120 is configured to operate within the 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 be obtained, but also the amount of sludge generated can be reduced.

[0099] The first chemical C1 and the second chemical C2 can be put into the first coagulation tank 130. The first coagulation tank 130 can be configured to operate within a defluorination agent concentration range of 800 ppm to 1,700 ppm. When the first coagulation tank 130 is configured to operate within the defluorination agent 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 be obtained, but also the amount of sludge generated can be reduced.

[0100] In addition, the first coagulation tank 130 can be configured to operate within a pH range of 6.5±0.5. When the first coagulation tank 130 is configured to operate within the pH range, not only can high-quality treated water with low fluoride concentration, phosphorus concentration, chloride ion concentration, organic matter concentration, total nitrogen (TN), and BOD be obtained, but also the amount of sludge generated can be reduced.

[0101] The third chemical C3 can be put into the second coagulation tank 140. The second coagulation tank 140 can be configured to operate within a polymer coagulant concentration range of 3.0±1.0 ppm. When the second coagulation tank 140 is configured to operate within the 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 be obtained, but also the amount of sludge generated can be reduced.

[0102] Compared with the prior art, the wastewater treatment method and device according to one embodiment of the present invention having the above-described structure can provide the following effects: reducing the total dosage of chemicals by 75% by weight, reducing the chloride ion concentration by 28%, increasing the nitrogen removal rate by 25%, reducing the site area by 9.7%, and reducing the amount of sludge generated.

[0103] Hereinafter, the present invention is described in more detail with reference to Examples, but the present invention is not limited to these Examples.

[0104] Production example: Production of device

[0105] Made with Figure 1 A wastewater treatment device composed of.

[0106] The wastewater treatment device is composed of a UV reaction tank, a pH adjustment tank, a first coagulation tank, a second coagulation tank, an inorganic precipitation tank, a biological treatment reaction tank and an organic precipitation tank.

[0107] Example 1: Operation of a wastewater treatment plant

[0108] As wastewater, semiconductor process wastewater was used, which had a pH of 2.5, a fluoride ion concentration F of 568ppm, a chloride ion concentration Cl of 50ppm, a PO4-P of 200ppm, an organic matter concentration of 400ppm, a total nitrogen (TN) concentration of 400ppm, and a BOD of 700ppm. Slaked lime was added to the pH adjustment tank, and slaked lime and aluminum chloride (AlCl3) were added to the first coagulation tank, and anionic polyacrylamide was added to the second coagulation tank. The content of slaked lime added to the pH adjustment tank was such that the pH (R2-pH) of the pH adjustment tank was maintained at 5.0. The content of aluminum chloride (AlCl3) added to the first coagulation tank was such that the concentration (R3-C2) of aluminum chloride (AlCl3) in the first coagulation tank was 1,200ppm. The content of slaked lime added to the first coagulation tank was such that the pH (R3-pH) of the first coagulation tank was maintained at 6.5. The content of anionic polyacrylamide added to the second coagulation tank is such that the concentration (R4-C3) of anionic polyacrylamide in the second coagulation tank is 3 ppm.

[0109] Example 2: Operation of a wastewater treatment plant

[0110] The wastewater treatment apparatus was operated in the same manner as in Example 1, except that the content of slaked lime introduced into 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.

[0111] Example 3: Operation of wastewater treatment plant

[0112] The wastewater treatment apparatus was operated in the same manner as in Example 1, except that the content of slaked lime introduced into 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.

[0113] Example 4: Operation of wastewater treatment plant

[0114] The wastewater treatment device was operated in the same manner as in Example 1, except that the content of aluminum chloride (AlCl3) fed into the first coagulation tank was changed to an amount such that the concentration (R3-C2) of aluminum chloride (AlCl3) in the first coagulation tank was maintained at 800 ppm.

[0115] Example 5: Operation of wastewater treatment plant

[0116] The wastewater treatment device was operated in the same manner as in Example 1, except that the content of aluminum chloride (AlCl3) fed into the first coagulation tank was changed to an amount such that the concentration (R3-C2) of aluminum chloride (AlCl3) in the first coagulation tank was maintained at 1,700 ppm.

[0117] Reference Example 1: Operation of Wastewater Treatment Plant

[0118] The wastewater treatment apparatus was operated in the same manner as in Example 1, except that the content of slaked lime introduced into 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.

[0119] Reference Example 2: Operation of Wastewater Treatment Plant

[0120] The wastewater treatment apparatus was operated in the same manner as in Example 1, except that the content of slaked lime introduced into 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.

[0121] Reference Example 3: Operation of Wastewater Treatment Plant

[0122] The wastewater treatment device was operated in the same manner as in Example 1, except that the content of aluminum chloride (AlCl3) fed into the first coagulation tank was changed to an amount such that the concentration (R3-C2) of aluminum chloride (AlCl3) in the first coagulation tank was maintained at 700 ppm.

[0123] Reference example 4: Operation of wastewater treatment plant

[0124] The wastewater treatment device was operated in the same manner as in Example 1, except that the content of aluminum chloride (AlCl3) fed into the first coagulation tank was changed to an amount such that the concentration (R3-C2) of aluminum chloride (AlCl3) in the first coagulation tank was maintained at 1,800 ppm.

[0125] Comparative Example 1: Operation of Wastewater Treatment Plant

[0126] The wastewater treatment apparatus 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 content of the hydrogen peroxide removal agent (catalase) introduced into the hydrogen peroxide removal tank was changed to an amount such that the concentration of the hydrogen peroxide removal agent (catalase) in the hydrogen peroxide removal tank was 500 ppm.

[0127] Comparative Example 2: Operation of Wastewater Treatment Plant

[0128] The wastewater treatment apparatus 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 content of the hydrogen peroxide removal agent (catalase) introduced into the hydrogen peroxide removal tank was changed to an amount such that the concentration of the hydrogen peroxide removal agent (catalase) in the hydrogen peroxide removal tank was 500 ppm.

[0129] Comparative Example 3: Operation of Wastewater Treatment Plant

[0130] The wastewater treatment apparatus 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 content of the hydrogen peroxide removal agent (catalase) introduced into the hydrogen peroxide removal tank was changed to an amount such that the concentration of the hydrogen peroxide removal agent (catalase) in the hydrogen peroxide removal tank was 500 ppm.

[0131] Comparative Example 4: Operation of Wastewater Treatment Plant

[0132] The wastewater treatment apparatus 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 content of the hydrogen peroxide removal agent (catalase) introduced into the hydrogen peroxide removal tank was changed to an amount such that the concentration of the hydrogen peroxide removal agent (catalase) in the hydrogen peroxide removal tank was 500 ppm.

[0133] Comparative Example 5: Operation of Wastewater Treatment Plant

[0134] The wastewater treatment apparatus 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 content of the hydrogen peroxide removal agent (catalase) introduced into the hydrogen peroxide removal tank was changed to an amount such that the concentration of the hydrogen peroxide removal agent (catalase) in the hydrogen peroxide removal tank was 500 ppm.

[0135] The operating conditions (pH, amount of chemical input and chemical type) of the wastewater treatment devices of Examples 1 to 5, Reference Examples 1 to 4 and Comparative Examples 1 to 5 are summarized as shown in Table 1.

[0136]

Table 1

[0137]

[0138] Evaluation Example 1: Measurement of the concentration of residual hydrogen peroxide in treated water according to the residence time during UV treatment change The concentration of residual hydrogen peroxide in the treated water was measured according to the residence time during UV treatment in the UV reaction tank. The results are as follows: Figure 3 At this time, the UV irradiation is 45W / m 2 , using a UV lamp.

[0139] See also Figure 3 , when the residence time is 20 min, the hydrogen peroxide removal efficiency is about 73%.

[0140] Evaluation Example 2: Removal rate of refractory organic matter during UV treatment and biological treatment

[0141] The removal rates of refractory organic matter during UV treatment in the UV reaction tank and biological treatment in the biological treatment tank were measured using a liquid chromatography-organic carbon detector (LC-OCD). Figure 4 shown.

[0142] Figure 4(a) is the peak value of wastewater (i.e., raw water), (b) is the peak value of UV-treated water on the first day, (c) is the peak value of biologically treated water on the first day, (d) is the peak value of UV-treated water on the second day, and (e) is the peak value of biologically treated water on the second day.

[0143] See also Figure 4 , in biological treatment, almost no recalcitrant organic matter was removed, but in UV treatment, when the residence time was 20 minutes, 100% of the recalcitrant organic matter that inhibited nitrification was removed.

[0144] Evaluation Example 3: Performance Evaluation of Wastewater Treatment Equipment

[0145] The water quality of the final treated water (i.e., treated water discharged from the organic sedimentation tank) from the operation of the wastewater treatment apparatus according to Examples 1 to 5, Reference Examples 1 to 4, and Comparative Examples 1 to 5 was evaluated, and the results are shown in Table 2. In the following Table 2, "SS" is an abbreviation for "suspended solid" and "NM" is an abbreviation for "not measured".

[0146]

Table 2

[0147]

[0148]

[0149] Referring to Table 2, the wastewater treatment apparatuses of Examples 1 to 5 have superior water quality of final treated water compared to the wastewater treatment apparatuses of Reference Examples 1 to 4 and Comparative Examples 1 to 5.

[0150] According to the wastewater treatment method and device of one embodiment of the present invention, not only can the stability of inorganic wastewater treatment equipment and organic wastewater treatment equipment be improved, but also high-speed treatment can be achieved to save space (nitrification rate is increased by 25%), and it can be properly operated within the necessary range by using an automatic control system to remove hydrogen peroxide and difficult-to-degrade organic matter, thereby minimizing operating costs.

[0151] Although the present invention has been described with reference to the accompanying drawings and embodiments, this is merely exemplary, and those skilled in the art should understand that various modifications and equivalent other embodiments can be implemented thereby. Therefore, the true technical protection scope of the present invention should depend on the technical ideas of the attached claims.

[0152] Although the present invention has been described with reference to the accompanying drawings and embodiments, this is merely exemplary, and those skilled in the art should understand that various modifications and equivalent other embodiments can be implemented thereby. Therefore, the true technical protection scope of the present invention should depend on the technical ideas of the attached claims.

Claims

1. A wastewater treatment method comprising the following steps: The wastewater is passed 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 sedimentation tank to generate quinary treated water and sludge S10-5; Passing the five-stage treated water through a biological treatment reaction tank to generate six-stage treated water S10-6; and The sixth-stage treated water is passed through an organic sedimentation tank to generate seventh-stage treated water S10-7.

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

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

4. The wastewater treatment method according to claim 3, wherein: The first chemical includes slaked lime, the second chemical includes a defluoridating agent, and the third chemical includes a polymer coagulant.

5. The wastewater treatment method according to claim 4, wherein: The defluoridating agent includes aluminum chloride (AlCl3), sodium aluminate (NaAlO2) or a combination thereof, and the polymer coagulant includes anionic polyacrylamide, sodium alginate, sodium polyacrylate, maleate 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 cell 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 within the range of 3.5 to 6.

0.

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

9. The wastewater treatment method according to claim 8, wherein: The pH of the first coagulation tank is adjusted within the 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 coagulation tank is adjusted within the range of 3.0 ppm±1.0 ppm.

11. A wastewater treatment device, comprising: UV a reaction tank configured to generate primary treated water by irradiating UV light into wastewater; a pH adjustment tank configured to generate secondary treated water by adjusting the pH of the primary treated water; a first coagulation tank configured to generate tertiary treated water by partially coagulating the secondary treated water; a second coagulation tank configured to generate quaternary treated water by further partially coagulating the tertiary treated water; an inorganic sedimentation tank configured to generate fifth-stage treated water and sludge by partially sedimentating the fourth-stage treated water; A biological treatment reaction tank, which is configured to generate sixth-level treated water by further biologically treating the fifth-level treated water; as well as The organic sedimentation tank is configured to generate seventh-stage treated water and sludge by partially sedimentating the sixth-stage treated water.

12. The wastewater treatment device according to claim 11, wherein: The pH adjustment cell is configured to operate within a pH range of 3.5 to 6.

0.

13. The wastewater treatment device according to claim 12, wherein: The first coagulation tank is configured to operate within a defluorination agent concentration range of 800 ppm to 1,700 ppm.

14. The wastewater treatment device according to claim 13, wherein: The first coagulation tank is configured to operate within a pH range of 6.5±0.

5.

15. The wastewater treatment device according to claim 14, wherein: The second coagulation tank is configured to operate within a polymer coagulant concentration range of 3.0±1.0 ppm.

16. The wastewater treatment plant according to claim 11, further comprising 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 into the UV reaction tank, the first sensor is configured to measure the concentration of hydrogen peroxide in the wastewater, the second sensor is configured to measure at least one of the concentration of difficult-to-degrade organic matter in the wastewater and the concentration of difficult-to-degrade organic matter in the treated water discharged from the inorganic precipitation tank, the rectifier is configured to adjust the UV irradiation intensity of the UV lamp according to the signal of at least one of the first sensor and the second sensor, and the photocatalyst is configured to promote the decomposition of difficult-to-degrade organic matter in the wastewater when UV irradiated.

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