Wastewater treatment method and wastewater treatment device

Abstract

The invention relates to a wastewater treatment method and a wastewater treatment device. The disclosed wastewater treatment method comprises a first coagulative precipitation process and a second coagulative precipitation process which are continuously performed, and the first coagulative precipitation process comprises the following steps: wastewater passes through a first coagulative reaction tank to generate primary treatment water S10-2; enabling the primary treated water to pass through a third coagulation reaction tank to generate tertiary treated water S10-4; enabling the tertiary treated water to pass through a fourth coagulation reaction tank to generate quaternary treated water S10-6; the fourth-stage treated water passes through a first sedimentation tank to generate fifth-stage treated water and sludge S10-8; the second coagulating sedimentation process comprises the following steps: passing the fifth-stage treated water through a fifth coagulating reaction tank to generate sixth-stage treated water S20-2; enabling the sixth-stage treated water to pass through a seventh coagulation reaction tank to generate eighth-stage treated water S20-4; and enabling the eight-stage treated water to pass through a second sedimentation tank to generate nine-stage treated water and sludge S20-6.

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 achieve the effects of reducing the amount of medicine used, reducing the amount of sludge generated, and not increasing the concentration of chloride ions. Background Art

[0002] In order to remove fluorine, the existing wastewater treatment technology uses slaked lime and a chlorine-based defluorinating agent, and the pH is maintained at or above 8.5 by injecting slaked lime and the pH is neutralized by using the chlorine-based defluorinating agent.

[0003] Hydrated lime is a drug whose solubility decreases with increasing pH, so when operating at higher pH, excess hydrated lime must be added to meet target water quality.

[0004] In the case of wastewater containing fluorine and phosphorus, existing wastewater treatment technology effectively removes fluorine and phosphorus by excessively adding slaked lime.

[0005] In addition, in order to remove fluorine, the existing wastewater treatment process consists of a primary coagulation sedimentation process and a secondary coagulation sedimentation process, and slaked lime and chlorine-based defluorinating agents are mainly used as chemicals.

[0006] However, when strengthening the fluoride water quality standards, the existing wastewater treatment technology can achieve the goal by increasing the use of slaked lime and defluoridation agents. However, this causes side effects such as increased use of chemicals, increased chloride ion concentration, increased sludge production and reduced sedimentation. Summary of the invention

[0007] According to one embodiment of the present invention, a wastewater treatment method is provided, which can achieve the effects of reducing the amount of chemicals used, reducing the amount of sludge generated, and not increasing the chloride ion concentration.

[0008] According to another embodiment of the present invention, there is provided a wastewater treatment device, which can achieve the effects of reducing the amount of chemicals used, reducing the amount of sludge generated, and not increasing the chloride ion concentration.

[0009] In one aspect, the present invention provides a wastewater treatment method, which comprises

[0010] The first coagulation sedimentation process and the second coagulation sedimentation process are carried out continuously, wherein:

[0011] The first coagulation and sedimentation process comprises the following steps:

[0012] Passing the wastewater containing at least fluorine and phosphorus through a first coagulation reaction tank to generate primary treated water S10-2;

[0013] Passing the primary treated water through a third coagulation reaction tank to generate tertiary treated water S10-4;

[0014] Passing the tertiary treated water through a fourth coagulation reaction tank to generate quaternary treated water (S10-6); and

[0015] The quaternary treated water is passed through the first sedimentation tank to generate quinary treated water and sludge S10-8,

[0016] The second coagulation and sedimentation process comprises the following steps:

[0017] Passing the five-stage treated water through a fifth coagulation reaction tank to generate six-stage treated water S20-2;

[0018] Passing the sixth-stage treated water through a seventh coagulation reaction tank to generate eighth-stage treated water S20-4; and

[0019] The eighth-stage treated water is passed through a second sedimentation tank to generate ninth-stage treated water and sludge S20-6.

[0020] The first drug can be put into the first coagulation reaction tank, and the first drug and the second drug can be put into the third coagulation reaction tank, and the third drug can be put into the fourth coagulation reaction tank, and the second drug and the fourth drug can be put into the fifth coagulation reaction tank, and the third drug can be put into the seventh coagulation reaction tank.

[0021] The first chemical may include slaked lime, and the second chemical may include a chlorine-based defluorinating agent, and the third chemical may include a polymer coagulant, and the fourth chemical may include an alkali-based defluorinating agent.

[0022] The chlorine-based defluorination agent may include aluminum chloride (AlCl 3 ), and the polymer coagulant may include anionic polyacrylamide, sodium alginate, sodium polyacrylate, maleate copolymer, partial hydrolyzate of polyacrylamide or a combination thereof, and the alkaline defluoridation agent may include sodium aluminate (NaAlO 2 ).

[0023] The pH of the first coagulation reaction tank may be adjusted within a range of 3.5 to 6.0, and the pH of the fifth coagulation reaction tank may be adjusted within a range of 6.5 to 7.5.

[0024] The pH of the third coagulation reaction tank can be adjusted within the range of 7.0±0.5.

[0025] The concentration of the third chemical in the fourth coagulation reaction tank may be adjusted within the range of 3.0 ppm±0.5 ppm, and the concentration of the third chemical in the seventh coagulation reaction tank may be adjusted within the range of 3.0 ppm±0.5 ppm.

[0026] In addition, the concentration of the second chemical in the third coagulation reaction tank can be adjusted to 800 ppm to 1,700 ppm, and the concentration of the fourth chemical in the fifth coagulation reaction tank can be adjusted to 850 ppm to 2,000 ppm.

[0027] In the wastewater treatment method, between step S10-2 and step S10-4, there is further included a step S10-3 of passing the primary treated water through a second coagulation reaction tank to generate secondary treated water. In this case, step S10-4 may be a step of passing the primary treated water through the third coagulation reaction tank to generate tertiary treated water by replacing the primary treated water with the secondary treated water.

[0028] No additional chemicals may be added to the second coagulation reaction tank.

[0029] In the wastewater treatment method, between step S20-2 and step S20-4, there is further included a step S20-3 of passing the sixth-stage treated water through a sixth coagulation reaction tank to generate seventh-stage treated water. In this case, step S20-4 may be a step of replacing the sixth-stage treated water with the seventh-stage treated water and passing it through the seventh coagulation reaction tank to generate eighth-stage treated water.

[0030] No additional chemicals may be added to the sixth coagulation reaction tank.

[0031] Another aspect of the present invention provides a wastewater treatment device, comprising

[0032] A first coagulation and sedimentation unit and a second coagulation and sedimentation unit are connected in series, wherein:

[0033] The first coagulation and sedimentation unit comprises:

[0034] a first coagulation reaction tank configured to generate primary treated water by partially coagulating wastewater containing at least fluorine and phosphorus;

[0035] a third coagulation reaction tank, which is configured to generate tertiary treated water by further partially coagulating the primary treated water;

[0036] a fourth coagulation reaction tank configured to generate quaternary treated water by further partially coagulating the tertiary treated water; and

[0037] a first sedimentation tank configured to generate fifth-stage treated water and sludge by partially sedimentating the fourth-stage treated water;

[0038] The second coagulation and sedimentation unit comprises:

[0039] a fifth coagulation reaction tank configured to generate sixth-stage treated water by further partially coagulating the fifth-stage treated water;

[0040] a seventh coagulation reaction tank, configured to generate eighth-stage treated water by further partially coagulating the sixth-stage treated water; and

[0041] The second sedimentation tank is configured to generate ninth-stage treated water and sludge by partially sedimentating the eighth-stage treated water.

[0042] The first coagulation reaction tank is configured to operate within a pH range of 3.5 to 6.0, and the fifth coagulation reaction tank may be configured to operate within a pH range of 6.5 to 7.5.

[0043] The third coagulation reaction tank may be configured to operate within a pH range of 7.0±0.5.

[0044] The fourth coagulation reaction tank is configured to operate within a polymer coagulant concentration range of 3.0±0.5 ppm, and the seventh coagulation reaction tank may be configured to operate within a polymer coagulant concentration range of 3.0±0.5 ppm.

[0045] The third coagulation reaction tank is configured to operate within a chlorine-based defluorinating agent concentration range of 800 ppm to 1,700 ppm, and the fifth coagulation reaction tank may be configured to operate within a base-based defluorinating agent concentration range of 850 ppm to 2,000 ppm.

[0046] In the wastewater treatment device, a second coagulation reaction tank is further included between the first coagulation reaction tank and the third coagulation reaction tank, which is configured to generate secondary treated water by further partially coagulating the primary treated water. In this case, the third coagulation reaction tank can be configured to generate tertiary treated water by additionally treating the secondary treated water instead of the primary treated water.

[0047] In the wastewater treatment device, the fifth coagulation reaction tank and the seventh coagulation reaction tank further include a sixth coagulation reaction tank, which is configured to generate seventh-level treated water by further partially coagulating the sixth-level treated water. In this case, the seventh coagulation reaction tank can be configured to generate eighth-level treated water by additionally treating the seventh-level treated water instead of the sixth-level treated water. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 The figure schematically shows a wastewater treatment method and apparatus according to one embodiment of the present invention.

[0049] [Description of Reference Numerals]

[0050] 100: Wastewater treatment plant

[0051] 110, 120: Coagulation and sedimentation unit

[0052] 111 to 114, 121 to 123: Coagulation reaction tank

[0053] 115, 124: Sedimentation tank

[0054] WW: Wastewater

[0055] TW5, TW9: Treated water

[0056] C1 to C4: Pharmaceuticals

[0057] SLG1, SLG2: Sludge DETAILED DESCRIPTION

[0058] Hereinafter, a wastewater treatment method according to an embodiment of the present invention will be described in detail.

[0059] In this specification, the unit "ppm (parts per million)" means mg / L.

[0060] 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.

[0061] The wastewater treatment method and apparatus according to one embodiment of the present invention can remove fluorine, phosphorus, suspended solids (SS), organic matter, particulate matter and ionic matter in wastewater.

[0062] A wastewater treatment method according to an embodiment of the present invention includes a first coagulation and sedimentation process and a second coagulation and sedimentation process which are performed continuously.

[0063] The first coagulation and sedimentation process may include step S10-2 of passing the wastewater containing at least fluorine and phosphorus through a first coagulation reaction tank to generate primary treated water, step S10-4 of passing the primary treated water through a third coagulation reaction tank to generate tertiary treated water, step S10-6 of passing the tertiary treated water through a fourth coagulation reaction tank to generate quaternary treated water, and step S10-8 of passing the quaternary treated water through a first sedimentation tank to generate quinary treated water and sludge.

[0064] The first chemical can be put into the first coagulation reaction tank.

[0065] The first chemical may include slaked lime.

[0066] The pH of the first coagulation reaction tank can be adjusted within the range of 3.5 to 6.0. When the pH of the first coagulation reaction tank is within the range, not only can high-quality treated water with low fluoride concentration, phosphorus concentration, and chloride ion concentration be obtained, but also the amount of sludge generated can be reduced.

[0067] The first chemical and the second chemical can be put into the third coagulation reaction tank.

[0068] The second chemical may include a chlorine-based defluorinating agent.

[0069] The chlorine-based defluorination agent may include aluminum chloride (AlCl 3 ).

[0070] The pH of the third coagulation reaction tank can be adjusted within the range of 7.0±0.5. When the pH of the third coagulation reaction tank is within the range, not only can high-quality treated water with low fluoride concentration, phosphorus concentration, and chloride ion concentration be obtained, but also the amount of sludge generated can be reduced.

[0071] In addition, the concentration of the second chemical in the third coagulation reaction tank can be adjusted between 800 ppm and 1,700 ppm. When the concentration of the second chemical in the third coagulation reaction tank is within the above range, not only can high-quality treated water with low fluoride concentration, phosphorus concentration, and chloride ion concentration be obtained, but also the amount of sludge generated can be reduced.

[0072] The third drug can be put into the fourth coagulation reaction tank.

[0073] The third drug may include a polymer coagulant.

[0074] The polymer coagulant may include anionic polyacrylamide, sodium alginate, sodium polyacrylate, maleate copolymer, partial hydrolyzate of polyacrylamide, or a combination thereof.

[0075] The concentration of the third chemical in the fourth coagulation reaction tank can be adjusted within the range of 3.0ppm±0.5ppm. When the concentration of the third chemical in the fourth coagulation reaction tank is within the range, not only can high-quality treated water with low fluorine concentration, phosphorus concentration, and chloride ion concentration be obtained, but also the amount of sludge generated can be reduced.

[0076] In the wastewater treatment method, a step S10-3 of passing the primary treated water through a second coagulation reaction tank to generate secondary treated water may be further included between the step S10-2 and the step S10-4. In this case, the step S10-4 may be a step of passing the secondary treated water, instead of the primary treated water, through the third coagulation reaction tank to generate tertiary treated water. For example, when the wastewater contains hydrogen peroxide, the wastewater treatment method includes the step S10-3, and when the wastewater does not contain hydrogen peroxide, or the amount present is negligible, the step S10-3 may not be included.

[0077] No additional chemicals may be added to the second coagulation reaction tank.

[0078] The second coagulation and sedimentation process may include step S20-2 of passing the fifth-level treated water through a fifth coagulation reaction tank to generate sixth-level treated water, step S20-4 of passing the sixth-level treated water through a seventh coagulation reaction tank to generate eighth-level treated water, and step S20-6 of passing the eighth-level treated water through a second sedimentation tank to generate ninth-level treated water and sludge.

[0079] The second drug and the fourth drug can be put into the fifth coagulation reaction tank.

[0080] The fourth chemical may include a base defluorinating agent.

[0081] The alkaline defluoridation agent may include sodium aluminate (NaAlO 2 ).

[0082] The pH of the fifth coagulation reaction tank can be adjusted within the range of 6.5 to 7.5. When the pH of the fifth coagulation reaction tank is within the range, not only can high-quality treated water with low fluoride concentration, phosphorus concentration, and chloride ion concentration be obtained, but also the amount of sludge generated can be reduced.

[0083] In addition, the concentration of the fourth chemical in the fifth coagulation reaction tank can be adjusted within a range of 850 ppm to 2,000 ppm. When the concentration of the fourth chemical in the fifth coagulation reaction tank is within the range, not only can high-quality treated water with low fluoride concentration, phosphorus concentration, and chloride ion concentration be obtained, but also the amount of sludge generated can be reduced.

[0084] The third chemical can be put into the seventh coagulation reaction tank.

[0085] The concentration of the third chemical in the seventh coagulation reaction tank can be adjusted within the range of 3.0ppm±0.5ppm. When the concentration of the third chemical in the seventh coagulation reaction tank is within the range, not only can high-quality treated water with low fluorine concentration, phosphorus concentration, and chloride ion concentration be obtained, but also the amount of sludge generated can be reduced.

[0086] In the wastewater treatment method, a step S20-3 of passing the six-stage treated water through a sixth coagulation reaction tank to generate seven-stage treated water may be further included between the step S20-2 and the step S20-4. In this case, the step S20-4 may be a step of passing the seven-stage treated water through the seventh coagulation reaction tank instead of the six-stage treated water to generate eight-stage treated water.

[0087] No additional chemicals may be added to the sixth coagulation reaction tank.

[0088] In the following, see Figure 1 , a wastewater treatment device 100 according to an embodiment of the present invention will be described in detail.

[0089] A wastewater treatment apparatus 100 according to an embodiment of the present invention includes a first coagulation and sedimentation unit 110 and a second coagulation and sedimentation unit 120 connected in series to each other.

[0090] The first coagulation and sedimentation unit 110 may include a first coagulation reaction tank 111 , a third coagulation reaction tank 113 , a fourth coagulation reaction tank 114 and a first sedimentation tank 115 .

[0091] The first coagulation reaction tank 111 may be configured to treat the wastewater WW containing at least fluorine and phosphorus to generate primary treated water.

[0092] The first chemical C1 can be put into the first coagulation reaction tank 111. The first coagulation reaction tank 111 can be configured to operate within a pH range of 3.5 to 6.0. When the first coagulation reaction tank 111 is configured to operate within the pH range, not only can high-quality treated water with low fluoride concentration, phosphorus concentration, and chloride ion concentration be obtained, but also the amount of sludge generated can be reduced.

[0093] The third coagulation reaction tank 113 may be configured to generate tertiary treated water by further partially coagulating the primary treated water.

[0094] The first drug C1 and the second drug C2 can be put into the third coagulation reaction tank 113. The third coagulation reaction tank 113 can be configured to operate within a pH range of 7.0±0.5. When the third coagulation reaction tank is configured to operate within the pH range, not only can high-quality treated water with low fluoride concentration, phosphorus concentration, and chloride ion concentration be obtained, but also the amount of sludge generated can be reduced.

[0095] In addition, the third coagulation reaction tank 113 can be configured to operate within a chlorine-based defluorinating agent concentration range of 800 ppm to 1,700 ppm. When the third coagulation reaction tank 113 is configured to operate within the chlorine-based defluorinating agent concentration range, not only can high-quality treated water with low fluorine concentration, phosphorus concentration, and chloride ion concentration be obtained, but also the amount of sludge generated can be reduced.

[0096] The fourth coagulation reaction tank 114 may be configured to generate quaternary treated water by further partially coagulating the tertiary treated water.

[0097] The third chemical C3 can be put into the fourth coagulation reaction tank 114. The fourth coagulation reaction tank 114 can be configured to operate within a polymer coagulant concentration range of 3.0±0.5ppm. When the fourth coagulation reaction tank 114 is configured to operate within a polymer coagulant concentration range of 3.0±0.5ppm, not only can high-quality treated water with low fluorine concentration, phosphorus concentration, and chloride ion concentration be obtained, but also the amount of sludge generated can be reduced.

[0098] In addition, the wastewater treatment device 100 may further include a second coagulation reaction tank 112 between the first coagulation reaction tank 111 and the third coagulation reaction tank 113, which is configured to generate secondary treated water by further partially coagulating the primary treated water. In this case, the third coagulation reaction tank 113 may be configured to generate tertiary treated water by additionally treating the secondary treated water instead of the primary treated water. For example, when the wastewater contains hydrogen peroxide, the wastewater treatment device 100 includes the second coagulation reaction tank 112, and when the wastewater does not contain hydrogen peroxide, or the amount present is negligible, the second coagulation reaction tank 112 may not be included.

[0099] No additional chemicals may be added to the second coagulation reaction tank 112 .

[0100] The first sedimentation tank 115 may be configured to partially sediment the quaternary treated water to generate quinary treated water TW5 and sludge SLG1.

[0101] The second coagulation and sedimentation unit 120 may include a fifth coagulation reaction tank 121 , a seventh coagulation reaction tank 123 , and a second sedimentation tank 124 .

[0102] The fifth coagulation reaction tank 121 may be configured to further process the fifth-stage treated water TW5 to generate sixth-stage treated water.

[0103] The second drug C2 and the fourth drug C4 can be put into the fifth coagulation reaction tank 121. The fifth coagulation reaction tank 121 can be configured to operate within a pH range of 6.5 to 7.5. When the fifth coagulation reaction tank 121 is configured to operate within the pH range, not only can high-quality treated water with low fluorine concentration, phosphorus concentration, and chloride ion concentration be obtained, but also the amount of sludge generated can be reduced.

[0104] In addition, the fifth coagulation reaction tank 121 can be configured to operate within a base defluorinating agent concentration range of 850 ppm to 2,000 ppm. When the fifth coagulation reaction tank 121 is configured to operate within the base defluorinating agent concentration range, not only can high-quality treated water with low fluorine concentration, phosphorus concentration, and chloride ion concentration be obtained, but also the amount of sludge generated can be reduced.

[0105] The seventh coagulation reaction tank 123 may be configured to generate eighth-stage treated water by further partially coagulating the sixth-stage treated water.

[0106] The third chemical C3 can be put into the seventh coagulation reaction tank 123. The seventh coagulation reaction tank 123 can be configured to operate within a polymer coagulant concentration range of 3.0±0.5ppm. When the seventh coagulation reaction tank 123 is configured to operate within the polymer coagulant concentration range, not only can high-quality treated water with low fluorine concentration, phosphorus concentration, and chloride ion concentration be obtained, but also the amount of sludge generated can be reduced.

[0107] In addition, the wastewater treatment device 100 may further include a sixth coagulation reaction tank 122 between the fifth coagulation reaction tank 121 and the seventh coagulation reaction tank 123, which is configured to generate seventh-level treated water by further partially coagulating the sixth-level treated water. In this case, the seventh coagulation reaction tank 123 may be configured to generate eighth-level treated water by additionally treating the seventh-level treated water instead of the sixth-level treated water.

[0108] The second sedimentation tank 124 may be configured to partially sediment the eighth-stage treated water to generate ninth-stage treated water TW9 and sludge SLG2.

[0109] In addition, the first to seventh coagulation reaction tanks 111 to 123 may be respectively equipped with a stirrer st.

[0110] Compared with the prior art, the wastewater treatment method and apparatus according to one embodiment of the present invention having the above-described structure can provide the following effects: reducing the total amount of chemicals used by 60 weight%, reducing the amount of sludge produced by 20 weight% and not increasing the chloride ion concentration.

[0111] Hereinafter, the present invention is described in more detail with reference to Examples, but the present invention is not limited to these Examples.

[0112] Production example: Production of device

[0113] Made with Figure 1 A wastewater treatment device composed of.

[0114] The manufactured wastewater treatment device consists of a first coagulation and sedimentation unit and a second coagulation and sedimentation unit.

[0115] The first coagulation and sedimentation unit is composed of a first coagulation reaction tank, a second coagulation reaction tank, a third coagulation reaction tank, a fourth coagulation reaction tank and a first sedimentation tank.

[0116] The second coagulation and sedimentation unit is composed of a fifth coagulation reaction tank, a sixth coagulation reaction tank, a seventh coagulation reaction tank and a second sedimentation tank.

[0117] Example 1: Operation of a wastewater treatment plant

[0118] Semiconductor process wastewater was used as wastewater, which had a pH of 3.08, a fluoride ion concentration F of 644 ppm, a chloride ion concentration Cl of 33.0 ppm, and a PO 4 -P is 160ppm. Slaked lime is added to the first coagulation reaction tank, and no additional chemicals are added to the second coagulation reaction tank, and slaked lime and aluminum chloride (AlCl 3 ) is put into the third coagulation reaction tank, and anionic polyacrylamide is put into the fourth coagulation reaction tank. The content of slaked lime put into the first coagulation reaction tank is such that the pH (R1-pH) of the first coagulation reaction tank is maintained at 3.5. Aluminum chloride (AlCl 3 ) is such that the aluminum chloride (AlCl 3 ) concentration (R3-C2) is 1,250 ppm. The content of slaked lime added to the third coagulation reaction tank is such that the pH (R3-pH) of the third coagulation reaction tank is maintained at 7.0. The content of anionic polyacrylamide added to the fourth coagulation reaction tank is such that the concentration (R4-C3) of anionic polyacrylamide in the fourth coagulation reaction tank is 3 ppm. Aluminum chloride (AlCl 3 ) and sodium aluminate (NaAlO 2 ) is put into the fifth coagulation reaction tank, and no additional chemicals are put into the sixth coagulation reaction tank, and anionic polyacrylamide is put into the seventh coagulation reaction tank. Sodium aluminate (NaAlO 2 ) is such that the sodium aluminate (NaAlO 2) concentration (R5-C4) is 1,425 ppm. 3 ) is an amount that maintains the pH (R5-pH) of the fifth coagulation reaction tank at 7.0. The content of anionic polyacrylamide put into the seventh coagulation reaction tank is an amount that makes the concentration (R7-C3) of anionic polyacrylamide in the seventh coagulation reaction tank be 3 ppm.

[0119] Example 2: Operation of a 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 fed into the first coagulation reaction tank was changed to an amount such that the pH (R1-pH) of the first coagulation reaction tank was maintained at 5.0.

[0121] Example 3: Operation of wastewater treatment plant

[0122] The wastewater treatment apparatus was operated in the same manner as in Example 1, except that the content of slaked lime fed into the first coagulation reaction tank was changed to an amount such that the pH (R1-pH) of the first coagulation reaction tank was maintained at 6.0.

[0123] Example 4: Operation of wastewater treatment plant

[0124] In addition to the aluminum chloride (AlCl 3 ) is changed so that the aluminum chloride (AlCl 3 The wastewater treatment apparatus was operated in the same manner as in Example 2, except that the concentration (R3-C2) was 800 ppm.

[0125] Example 5: Operation of wastewater treatment plant

[0126] In addition to the aluminum chloride (AlCl 3 ) is changed so that the aluminum chloride (AlCl 3 The wastewater treatment apparatus was operated in the same manner as in Example 2 except that the concentration (R3-C2) was 1,700 ppm.

[0127] Example 6: Operation of wastewater treatment plant

[0128] In addition to the sodium aluminate (NaAlO 2 ) is changed to make the sodium aluminate (NaAlO 2The wastewater treatment apparatus was operated in the same manner as in Example 2, except that the concentration of (R5-C4) was maintained at 850 ppm.

[0129] Example 7: Operation of wastewater treatment plant

[0130] In addition to the sodium aluminate (NaAlO 2 ) is changed to make the sodium aluminate (NaAlO 2 The wastewater treatment apparatus was operated in the same manner as in Example 2 except that the concentration of (R5-C4) was maintained at 2,000 ppm.

[0131] Example 8: Operation of wastewater treatment plant

[0132] In addition to the aluminum chloride (AlCl 3 ) was adjusted to an amount such that the pH (R5-pH) of the fifth coagulation reaction tank was maintained at 6.5, and the wastewater treatment device was operated in the same manner as in Example 2.

[0133] Example 9: Operation of wastewater treatment plant

[0134] In addition to the aluminum chloride (AlCl 3 ) was adjusted to an amount such that the pH (R5-pH) of the fifth coagulation reaction tank was maintained at 7.5, and the wastewater treatment device was operated in the same manner as in Example 2.

[0135] Reference Example 1: Operation of Wastewater Treatment Plant

[0136] 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 reaction tank was adjusted to an amount such that the pH (R1-pH) of the first coagulation reaction tank was maintained at 3.0.

[0137] Reference Example 2: Operation of Wastewater Treatment Plant

[0138] 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 reaction tank was adjusted to an amount such that the pH (R1-pH) of the first coagulation reaction tank was maintained at 7.0.

[0139] Reference Example 3: Operation of Wastewater Treatment Plant

[0140] In addition to the aluminum chloride (AlCl 3 ) is adjusted so that the aluminum chloride (AlCl3 The wastewater treatment apparatus was operated in the same manner as in Example 2, except that the concentration (R3-C2) was maintained at 600 ppm.

[0141] Reference example 4: Operation of wastewater treatment plant

[0142] In addition to the aluminum chloride (AlCl 3 ) is adjusted so that the aluminum chloride (AlCl 3 The wastewater treatment apparatus was operated in the same manner as in Example 2 except that the concentration of (R3-C2) was maintained at 1,900 ppm.

[0143] Reference Example 5: Operation of Wastewater Treatment Plant

[0144] In addition to the sodium aluminate (NaAlO 2 ) is adjusted so that the content of sodium aluminate (NaAlO 2 The wastewater treatment apparatus was operated in the same manner as in Example 2, except that the concentration of (R5-C4) was maintained at 750 ppm.

[0145] Reference Example 6: Operation of Wastewater Treatment Plant

[0146] In addition to the sodium aluminate (NaAlO 2 ) is adjusted so that the content of sodium aluminate (NaAlO 2 The wastewater treatment apparatus was operated in the same manner as in Example 2 except that the concentration of (R5-C4) was maintained at 2,100 ppm.

[0147] Reference Example 7: Operation of Wastewater Treatment Plant

[0148] In addition to the aluminum chloride (AlCl 3 ) was adjusted to an amount such that the pH (R5-pH) of the fifth coagulation reaction tank was maintained at 6.0, and the wastewater treatment device was operated in the same manner as in Example 2.

[0149] Reference Example 8: Operation of Wastewater Treatment Plant

[0150] In addition to the aluminum chloride (AlCl 3 ) was adjusted to an amount such that the pH (R5-pH) of the fifth coagulation reaction tank was maintained at 8.0, and the wastewater treatment device was operated in the same manner as in Example 2.

[0151] Reference Example 9: Operation of Wastewater Treatment Plant

[0152] In addition to the aluminum chloride (AlCl 3 ) is replaced by aluminum sulfate (Al 2 (SO 4 ) 3 ) so that the concentration of aluminum sulfate (R3-C2') in the third coagulation reaction tank is maintained at 1,250 ppm, the wastewater treatment device is operated in the same manner as in Example 2.

[0153] Reference Example 10: Operation of Wastewater Treatment Plant

[0154] In addition to the sodium aluminate (NaAlO 2 ) was replaced with slaked lime so that the concentration R5-C1 of slaked lime in the fifth coagulation reaction tank was maintained at 1,425 ppm, and the wastewater treatment device was operated in the same manner as in Example 2.

[0155] The operating conditions (pH, amount of chemical input and chemical type) of the wastewater treatment devices of Examples 1 to 9 and Reference Examples 1 to 10 are summarized as shown in Table 1.

[0156]

Table 1

[0157]

[0158] Evaluation example: Performance evaluation of wastewater treatment equipment

[0159] The water quality of the final treated water (i.e., the treated water discharged from the second sedimentation tank) from the operation of the wastewater treatment devices according to Examples 1 to 9 and Reference Examples 1 to 10 was evaluated, and the results are shown in Table 2.

[0160]

Table 2

[0161]

[0162]

[0163] As shown in Table 2, compared with the wastewater treatment devices of Reference Examples 1 to 10, the water quality of the final treated water of the wastewater treatment devices of Examples 1 to 9 is excellent.

[0164] According to an embodiment of the present invention, a wastewater treatment method and apparatus can be provided, which can provide the following effects: compared with the prior art, the amount of chemicals used is reduced by 60 weight%, the amount of sludge generated is reduced by 20 weight%, and the chloride ion concentration is not increased.

[0165] 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 a first coagulation and sedimentation process and a second coagulation and sedimentation process performed continuously, wherein: The first coagulation and sedimentation process comprises the following steps: S10-2: passing the wastewater containing at least fluorine and phosphorus through a first coagulation reaction tank to generate primary treated water; S10-4: passing the primary treated water through a third coagulation reaction tank to generate tertiary treated water; S10-6: passing the tertiary treated water through a fourth coagulation reaction tank to generate quaternary treated water; and S10-8: passing the quaternary treated water through a first sedimentation tank to generate quinary treated water and sludge, The second coagulation and sedimentation process comprises the following steps: S20-2: passing the five-stage treated water through a fifth coagulation reaction tank to generate six-stage treated water; S20-4: passing the sixth-stage treated water through a seventh coagulation reaction tank to generate eighth-stage treated water; and S20-6: Pass the eighth-stage treated water through a second sedimentation tank to generate ninth-stage treated water and sludge.

2. The wastewater treatment method according to claim 1, wherein: The first drug is put into the first coagulation reaction tank, and the first drug and the second drug are put into the third coagulation reaction tank, and the third drug is put into the fourth coagulation reaction tank, and the second drug and the fourth drug are put into the fifth coagulation reaction tank, and the third drug is put into the seventh coagulation reaction tank.

3. The wastewater treatment method according to claim 2, wherein: The first chemical includes slaked lime, and the second chemical includes a chlorine-based defluorinating agent, and the third chemical includes a polymer coagulant, and the fourth chemical includes an alkali-based defluorinating agent.

4. The wastewater treatment method according to claim 3, wherein: The chlorine-based defluoridant includes aluminum chloride AlCl3, and the polymer coagulant includes anionic polyacrylamide, sodium alginate, sodium polyacrylate, maleate copolymer, partial hydrolyzate of polyacrylamide or a combination thereof, and the base-based defluoridant includes sodium aluminate NaAlO2.

5. The wastewater treatment method according to claim 3, wherein: The pH of the first coagulation reaction tank is adjusted within a range of 3.5 to 6.0, and the pH of the fifth coagulation reaction tank is adjusted within a range of 6.5 to 7.

5.

6. The wastewater treatment method according to claim 5, wherein: The pH of the third coagulation reaction tank is adjusted within the range of 7.0±0.

5.

7. The wastewater treatment method according to claim 6, wherein: The concentration of the third chemical in the fourth coagulation reaction tank is adjusted within the range of 3.0 ppm±0.5 ppm, and the concentration of the third chemical in the seventh coagulation reaction tank is adjusted within the range of 3.0 ppm±0.5 ppm.

8. The wastewater treatment method according to claim 3, wherein: The concentration of the second chemical in the third coagulation reaction tank is adjusted to 800 ppm to 1,700 ppm, and the concentration of the fourth chemical in the fifth coagulation reaction tank is adjusted to 850 ppm to 2,000 ppm.

9. The wastewater treatment method according to claim 1, wherein: Between step S10-2 and step S10-4, there is further included a step S10-3 of passing the primary treated water through a second coagulation reaction tank to generate secondary treated water. In this case, step S10-4 is a step of passing the secondary treated water, rather than the primary treated water, through the third coagulation reaction tank to generate tertiary treated water.

10. The wastewater treatment method according to claim 9, wherein: No additional chemicals are added to the second coagulation reaction tank.

11. The wastewater treatment method according to claim 1, wherein: Between step S20-2 and step S20-4, step S20-3 is further included in which the sixth-stage treated water is passed through a sixth coagulation reaction tank to generate seventh-stage treated water. In this case, step S20-4 is a step in which the seventh-stage treated water, rather than the sixth-stage treated water, is passed through the seventh coagulation reaction tank to generate eighth-stage treated water.

12. The wastewater treatment method according to claim 11, wherein: No additional chemicals are added to the sixth coagulation reaction tank.

13. A wastewater treatment device, comprising a first coagulation sedimentation unit and a second coagulation sedimentation unit connected in series, wherein: The first coagulation and sedimentation unit comprises: a first coagulation reaction tank configured to generate primary treated water by partially coagulating wastewater containing at least fluorine and phosphorus; a third coagulation reaction tank, which is configured to generate tertiary treated water by further partially coagulating the primary treated water; a fourth coagulation reaction tank configured to generate quaternary treated water by further partially coagulating the tertiary treated water; and a first sedimentation tank configured to generate fifth-stage treated water and sludge by partially sedimentating the fourth-stage treated water; The second coagulation and sedimentation unit comprises: a fifth coagulation reaction tank configured to generate sixth-stage treated water by further partially coagulating the fifth-stage treated water; a seventh coagulation reaction tank, configured to generate eighth-stage treated water by further partially coagulating the sixth-stage treated water; and The second sedimentation tank is configured to generate ninth-stage treated water and sludge by partially sedimentating the eighth-stage treated water.

14. The wastewater treatment device according to claim 13, wherein: The first coagulation reaction tank is configured to operate within a pH range of 3.5 to 6.0, and the fifth coagulation reaction tank is configured to operate within a pH range of 6.5 to 7.

5.

15. The wastewater treatment device according to claim 14, wherein: The third coagulation reaction tank is configured to operate within a pH range of 7.0±0.

5.

16. The wastewater treatment device according to claim 15, wherein: The fourth coagulation reaction tank is configured to operate within a polymer coagulant concentration range of 3.0±0.5 ppm, and the seventh coagulation reaction tank is configured to operate within a polymer coagulant concentration range of 3.0±0.5 ppm.

17. The wastewater treatment device according to claim 15, wherein: The third coagulation reaction tank is configured to operate within a chlorine-based defluorinating agent concentration range of 800 ppm to 1,700 ppm, and the fifth coagulation reaction tank is configured to operate within a base-based defluorinating agent concentration range of 850 ppm to 2,000 ppm.

18. The wastewater treatment device according to claim 13, wherein: A second coagulation reaction tank is further included between the first coagulation reaction tank and the third coagulation reaction tank, which is configured to generate secondary treated water by further partially coagulating the primary treated water. In this case, the third coagulation reaction tank is configured to generate tertiary treated water by additionally treating the secondary treated water instead of the primary treated water.

19. The wastewater treatment device according to claim 18, wherein: No additional chemicals are added to the second coagulation reaction tank.

20. The wastewater treatment device according to claim 13, wherein: A sixth coagulation reaction tank is further included between the fifth coagulation reaction tank and the seventh coagulation reaction tank, which is configured to generate seventh-level treated water by further partially coagulating the sixth-level treated water. In this case, the seventh coagulation reaction tank is configured to generate eighth-level treated water by additionally treating the seventh-level treated water instead of the sixth-level treated water.

21. The wastewater treatment device according to claim 20, wherein: No additional chemicals are added to the sixth coagulation reaction tank.

Images