Waste water treatment method and waste water treatment apparatus

Abstract

To provide a waste water treatment method and a waste water treatment apparatus.SOLUTION: A method includes a first flocculation sedimentation step and a second flocculation sedimentation step. The first flocculation sedimentation step includes stages of: generating primary treatment water by allowing waste water including fluorine and phosphorus to pass through a first flocculation reaction tank; generating secondary treatment water by allowing the primary treatment water to pass through a second flocculation reaction tank; generating tertiary treatment water by allowing the primary treatment water to pass through a third flocculation reaction tank; generating quaternary treatment water by allowing the tertiary treatment water to pass through a fourth flocculation reaction tank; and generating quinary treatment water and a sludge by allowing the quaternary treatment water to pass through a first settling tank. The second flocculation sedimentation step includes stages of: generating senary treatment water by allowing the quinary treatment water to pass through a fifth flocculation reaction tank; generating septenary treatment water by allowing the senary treatment water to pass through a sixth flocculation reaction tank; generating octonary treatment water by allowing the septenary treatment water to pass through a seventh flocculation reaction tank; and generating nonary treatment water and a sludge by allowing the octonary treatment water to pass through a second settling tank.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 which can achieve the effects of reducing the amount of chemicals used, reducing the amount of sludge generated, and preventing an increase in chloride ion concentration. [Background technology]

[0002] Conventional wastewater treatment technology uses hydrated lime and chlorine-based fluoride removers to remove fluoride, injecting hydrated lime to maintain the pH at 8.5 or higher, and using chlorine-based fluoride removers to neutralize the pH.

[0003] Slaked lime is a chemical whose solubility decreases as the pH increases. Therefore, the higher the pH level is, the more excess slaked lime must be added to achieve the target water quality.

[0004] In the conventional wastewater treatment technology, when wastewater contains fluorine and phosphorus, an excessive amount of hydrated lime is added to effectively remove the fluorine and phosphorus.

[0005] Furthermore, conventional wastewater treatment processes are comprised of a primary coagulation and sedimentation process and a secondary coagulation and sedimentation process for removing fluorine, and the chemicals mainly used are hydrated lime and a chlorine-based fluoride remover.

[0006] However, in the case of conventional wastewater treatment technologies, when the fluoride water quality standards are strengthened, the target can be achieved by increasing the amount of chemicals such as hydrated lime and fluoride removers, but this has side effects such as increased chemical usage, increased chloride ion concentration, increased sludge generation, and decreased settling ability. Summary of the Invention [Problem to be solved by the invention]

[0007] The problem to be solved by the present invention is to provide a method for treating wastewater which can achieve the effects of reducing the amount of chemicals used, reducing the amount of sludge generated, and preventing an increase in the chloride ion concentration.

[0008] Another object of the present invention is to provide a wastewater treatment apparatus which can achieve the effects of reducing the amount of chemicals used, reducing the amount of sludge generated, and preventing an increase in the chloride ion concentration. [Means for solving the problem]

[0009] One aspect of the present invention is The method includes a first coagulation / sedimentation process and a second coagulation / sedimentation process which are carried out successively, The first coagulation and precipitation step includes: A step (S10-2) of passing 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 flocculation reactor to generate tertiary treated water; (S10-6) passing the tertiary effluent through a fourth flocculation reactor to produce a fourth effluent; and (S10-8) passing the quaternary effluent through a first settling tank to produce quinary effluent and sludge; The second coagulation and precipitation step includes: (S20-2) passing the fifth effluent through a fifth flocculation reactor to generate sixth effluent; (S20-4) passing the sixth effluent through a seventh flocculation reactor to generate eighth effluent; and (S20-6) passing the eighth effluent through a second settling tank to produce a ninth effluent and sludge.

[0010] A first chemical may be added to the first flocculation reaction tank, a first chemical and a second chemical may be added to the third flocculation reaction tank, a third chemical may be added to the fourth flocculation reaction tank, a second chemical and a fourth chemical may be added to the fifth flocculation reaction tank, and a third chemical may be added to the seventh flocculation reaction tank.

[0011] The first chemical includes hydrated lime, the second chemical includes a chlorine-based fluoride remover, the third chemical includes a polymer flocculant, and the fourth chemical includes an alkali-based fluoride remover.

[0012] The chlorine-based fluorine remover is aluminum chloride (AlCl 3 ), the polymeric flocculant comprises anionic polyacrylamide, sodium alginate, sodium polyacrylate, maleic acid copolymer, partial hydrolyzate of polyacrylamide, or a combination thereof, and the alkaline fluoride removing agent comprises sodium aluminate (NaAlO 2 ) may also be included.

[0013] The pH of the first flocculation reactor may be adjusted to a range of 3.5 to 6.0, and the pH of the fifth flocculation reactor may be adjusted to a range of 6.5 to 7.5.

[0014] The pH of the third flocculation reactor may be adjusted to a range of 7.0±0.5.

[0015] The concentration of the third chemical in the fourth flocculation reactor may be adjusted to within a range of 3.0±0.5 ppm, and the concentration of the third chemical in the seventh flocculation reactor may be adjusted to within a range of 3.0±0.5 ppm.

[0016] The concentration of the second chemical in the third flocculation reactor may be adjusted to 800 to 1,700 ppm, and the concentration of the fourth chemical in the fifth flocculation reactor may be adjusted to 850 to 2,000 ppm.

[0017] The wastewater treatment method further includes a step (S10-3) between steps (S10-2) and (S10-4) of passing the primary treated water through a second coagulation reaction tank to produce secondary treated water. In that case, step (S10-4) is also a step of passing the secondary treated water, instead of the primary treated water, through the third coagulation reaction tank to produce tertiary treated water.

[0018] No chemicals are added separately to the second flocculation reactor.

[0019] The wastewater treatment method further includes a step (S20-3) between steps (S20-2) and (S20-4) of passing the sixth effluent through a sixth coagulation reaction tank to produce seventh effluent, in which case step (S20-4) is also a step of passing the seventh effluent through the seventh coagulation reaction tank instead of the sixth effluent to produce eighth effluent.

[0020] No chemicals are added separately to the sixth flocculation reactor.

[0021] Another aspect of the present invention is The method includes the steps of: a first flocculation / sedimentation unit and a second flocculation / sedimentation unit connected in series with each other; The first flocculation / sedimentation unit comprises: a first flocculation reaction tank configured to partially flocculate wastewater containing at least fluorine and phosphorus to produce a primary effluent; a third flocculation reactor configured to add and partially flocculate the primary effluent to produce a tertiary effluent; A fourth flocculation reaction tank configured to add the tertiary effluent and partially flocculate it to produce a fourth effluent; a first settling tank configured to partially settle the quaternary effluent and produce a quinary effluent and a sludge; The second flocculation / sedimentation unit comprises: A fifth flocculation reaction tank configured to add the fifth effluent and partially flocculate it to generate sixth effluent; A seventh flocculation reaction tank configured to add the sixth effluent and partially flocculate it to generate an eighth effluent; and a second settling tank configured to partially settle the 8th effluent and produce 9th effluent and sludge.

[0022] The first flocculation reactor may be configured to operate in a pH range of 3.5 to 6.0, and the fifth flocculation reactor may be configured to operate in a pH range of 6.5 to 7.5.

[0023] The third flocculation reactor may be configured to operate at a pH range of 7.0±0.5.

[0024] The fourth flocculation reactor may be configured to operate with a polymer flocculant concentration range of 3.0±0.5 ppm, and the seventh flocculation reactor may be configured to operate with a polymer flocculant concentration range of 3.0±0.5 ppm.

[0025] The third coagulation reactor may be configured to operate with a chlorine-based fluoride removing agent concentration range of 800 to 1,700 ppm, and the fifth coagulation reactor may be configured to operate with an alkali-based fluoride removing agent concentration range of 850 to 2,000 ppm.

[0026] The wastewater treatment device further includes a second coagulation reaction tank between the first coagulation reaction tank and the third coagulation reaction tank, configured to add the primary treated water and partially coagulate it to produce secondary treated water. In this case, the third coagulation reaction tank is also configured to add and treat the secondary treated water instead of the primary treated water to produce tertiary treated water.

[0027] The wastewater treatment device further includes a sixth coagulation reaction tank between the fifth coagulation reaction tank and the seventh coagulation reaction tank, which is configured to add the sixth effluent water and partially coagulate it to produce seventh effluent. In this case, the seventh coagulation reaction tank is configured to add and treat the seventh effluent water instead of the sixth effluent water to produce eighth effluent. Effect of the Invention

[0028] According to an embodiment of the present invention, a wastewater treatment method and apparatus can be provided that can reduce the amount of chemicals used by 60% by weight, reduce the amount of sludge generated by 20% by weight, and prevent an increase in chloride ion concentration, compared to the existing technology. [Brief description of the drawings]

[0029] [Figure 1]1 is a schematic diagram illustrating a wastewater treatment method and apparatus according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] Hereinafter, a method for treating wastewater according to an embodiment of the present invention will be described in detail.

[0031] In this specification, the unit "ppm (parts per million)" means mg / L.

[0032] In this specification, the term "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 the term "rear end or rear end portion" means a portion or end portion located relatively in the forward direction of the flow direction of wastewater.

[0033] The wastewater treatment method and apparatus according to an embodiment of the present invention can remove fluorine, phosphorus, suspended solids (SS), organic matter, particulate matter, and ionic matter from wastewater.

[0034] A wastewater treatment method according to an embodiment of the present invention includes a first coagulation-sedimentation process and a second coagulation-sedimentation process which are carried out in succession.

[0035] The first coagulation and sedimentation process also includes a step (S10-2) of passing wastewater containing at least fluorine and phosphorus through a first coagulation reaction tank to produce primary treated water, a step (S10-4) of passing the primary treated water through a third coagulation reaction tank to produce tertiary treated water, a step (S10-6) of passing the tertiary treated water through a fourth coagulation reaction tank to produce quaternary treated water, and a step (S10-8) of passing the quaternary treated water through a first settling tank to produce quinary treated water and sludge.

[0036] A first chemical may be added to the first flocculation reactor.

[0037] The first chemical also includes hydrated lime.

[0038] The pH of the first coagulation reaction tank may be adjusted to a range of 3.5 to 6.0. When the pH of the first coagulation reaction tank is within this range, not only can high-quality treated water having low fluorine, phosphorus and chloride ion concentrations be obtained, but also the amount of sludge generation can be reduced.

[0039] The first chemical and the second chemical may be added to the third flocculation reactor.

[0040] The second chemical also includes a chlorine-based fluoride remover.

[0041] The chlorine-based fluorine remover is aluminum chloride (AlCl 3 ) may also be included.

[0042] The pH of the third coagulation reaction tank may be adjusted to within a range of 7.0±0.5. If the pH of the third coagulation reaction tank is within this range, not only can high-quality treated water having low fluorine, phosphorus and chloride ion concentrations be obtained, but also the amount of sludge generation can be reduced.

[0043] In addition, the second chemical concentration in the third coagulation reaction tank may be adjusted to 800 to 1,700 ppm. When the second chemical concentration in the third coagulation reaction tank is within this range, not only can high-quality treated water having low fluorine, phosphorus and chloride ion concentrations be obtained, but also the amount of sludge generation can be reduced.

[0044] A third chemical may be added to the fourth flocculation reactor.

[0045] The third chemical also includes a polymer flocculant.

[0046] The polymeric flocculant may also include anionic polyacrylamide, sodium alginate, sodium polyacrylate, maleic acid copolymers, partial hydrolysates of polyacrylamide, or combinations thereof.

[0047] The concentration of the third chemical in the fourth flocculation reaction tank may be adjusted to a range of 3.0±0.5 ppm. If the concentration of the third chemical in the fourth flocculation reaction tank is within this range, not only can high-quality treated water having low fluorine, phosphorus and chloride ion concentrations be obtained, but also the amount of sludge generation can be reduced.

[0048] The wastewater treatment method may further include a step (S10-3) between the steps (S10-2) and (S10-4) of passing the primary treated water through a second coagulation reaction tank to produce secondary treated water. In this case, the step (S10-4) is also a step of passing the secondary treated water, instead of the primary treated water, through the third coagulation reaction tank to produce tertiary treated water. For example, the wastewater treatment method includes the step (S10-3) when the wastewater contains hydrogen peroxide, and does not include the step (S10-3) when the wastewater does not contain hydrogen peroxide or contains a negligible amount of hydrogen peroxide.

[0049] No chemicals are added separately to the second flocculation reactor.

[0050] The second coagulation and sedimentation process also includes a step (S20-2) of passing the fifth effluent through a fifth coagulation reaction tank to produce sixth effluent, a step (S20-4) of passing the sixth effluent through a seventh coagulation reaction tank to produce eighth effluent, and a step (S20-6) of passing the eighth effluent through a second settling tank to produce ninth effluent and sludge.

[0051] The second chemical and the fourth chemical may be added to the fifth flocculation reactor.

[0052] The fourth chemical also includes an alkaline fluoride remover.

[0053] The alkaline fluoride remover is sodium aluminate (NaAlO 2 ) may also be included.

[0054] The pH of the fifth coagulation reaction tank may be adjusted to a range of 6.5 to 7.5. When the pH of the fifth coagulation reaction tank is within this range, not only can high-quality treated water having low fluorine, phosphorus and chloride ion concentrations be obtained, but also the amount of sludge generation can be reduced.

[0055] In addition, the concentration of the fourth chemical in the fifth coagulation reaction tank may be adjusted to 850 to 2,000 ppm. If the concentration of the fourth chemical in the fifth coagulation reaction tank is within this range, not only can high-quality treated water having low fluorine, phosphorus and chloride ion concentrations be obtained, but also the amount of sludge generation can be reduced.

[0056] The seventh flocculation reactor may be charged with the third chemical.

[0057] The concentration of the third chemical in the seventh flocculation reaction tank may be adjusted to a range of 3.0±0.5 ppm. If the concentration of the third chemical in the seventh flocculation reaction tank is within this range, not only can high-quality treated water having low fluorine, phosphorus and chloride ion concentrations be obtained, but also the amount of sludge generation can be reduced.

[0058] The wastewater treatment method may further include a step (S20-3) between the steps (S20-2) and (S20-4) of passing the sixth effluent through a sixth flocculation reactor to produce seventh effluent. In that case, the step (S20-4) is also a step of passing the seventh effluent through the seventh flocculation reactor instead of the sixth effluent to produce eighth effluent.

[0059] No chemicals are added separately to the sixth flocculation reactor.

[0060] Hereinafter, a wastewater treatment apparatus 100 according to an embodiment of the present invention will be described in detail with reference to FIG.

[0061] A wastewater treatment apparatus 100 according to an embodiment of the present invention includes a first coagulation / sedimentation unit 110 and a second coagulation / sedimentation unit 120 connected in series.

[0062] The first flocculation / sedimentation unit 110 also includes a first flocculation reaction tank 111, a third flocculation reaction tank 113, a fourth flocculation reaction tank 114 and a first settling tank 115.

[0063] The first flocculation reaction tank 111 can be configured to treat wastewater WW containing at least fluorine and phosphorus, and generate primary treated water.

[0064] The first flocculation reaction tank 111 may be configured to operate at a pH range of 3.5 to 6.0. If the first flocculation reaction tank 111 is configured to operate at this pH range, not only can high-quality treated water with low fluorine, phosphorus and chloride ion concentrations be obtained, but the amount of sludge generated can also be reduced.

[0065] The third flocculation reaction tank 113 may be configured to add and partially flocculate the primary treated water to generate tertiary treated water.

[0066] The third flocculation reactor 113 may be configured to operate at a pH range of 7.0±0.5. If the third flocculation reactor is configured to operate at this pH range, not only can high-quality treated water having low fluorine, phosphorus and chloride ion concentrations be obtained, but the amount of sludge generated can also be reduced.

[0067] In addition, the third coagulation reaction tank 113 may be configured to operate at a chlorine-based fluoride removing agent concentration range of 800 to 1,700 ppm. If the third coagulation reaction tank 113 is configured to operate at the chlorine-based fluoride removing agent concentration range, not only can high-quality treated water with low fluorine, phosphorus and chloride ion concentrations be obtained, but the amount of sludge generated can also be reduced.

[0068] The fourth flocculation reactor 114 may be configured to add and partially flocculate the tertiary effluent to generate quaternary effluent.

[0069] The fourth flocculation reaction tank 114 may be configured to operate at a polymer flocculant concentration range of 3.0±0.5 ppm. If the fourth flocculation reaction tank 114 is configured to operate at a polymer flocculant concentration range of 3.0±0.5 ppm, not only can high-quality treated water with low fluorine, phosphorus and chloride ion concentrations be obtained, but the amount of sludge generated can also be reduced.

[0070] The wastewater treatment device 100 further includes a second coagulation reaction tank 112 between the first coagulation reaction tank 111 and the third coagulation reaction tank 113, which is configured to add the primary treated water and partially coagulate it to generate secondary treated water. In this case, the third coagulation reaction tank 113 is configured to add and treat the secondary treated water instead of the primary treated water to generate tertiary treated water. For example, the wastewater treatment device 100 includes the second coagulation reaction tank 112 when the wastewater contains hydrogen peroxide, and does not include the second coagulation reaction tank 112 when the wastewater does not contain hydrogen peroxide or contains a negligible amount of hydrogen peroxide.

[0071] No chemicals are added separately to the second flocculation reactor 112 .

[0072] The first settling tank 115 may be configured to partially settle the quaternary effluent and produce a quinary effluent TW5 and a sludge SLG1.

[0073] The second flocculation / sedimentation unit 120 also includes a fifth flocculation reaction tank 121, a seventh flocculation reaction tank 123 and a second settling tank .

[0074] The fifth flocculation reaction tank 121 may be configured to additionally treat the fifth effluent TW5 to produce sixth effluent.

[0075] The fifth flocculation reaction tank 121 may be configured to operate at a pH range of 6.5 to 7.5. If the fifth flocculation reaction tank 121 is configured to operate at this pH range, not only can high-quality treated water with low fluorine, phosphorus and chloride ion concentrations be obtained, but the amount of sludge generated can also be reduced.

[0076] In addition, the fifth coagulation reaction tank 121 may be configured to operate at an alkaline fluoride removing agent concentration range of 850 to 2,000 ppm. If the fifth coagulation reaction tank 121 is configured to operate at an alkaline fluoride removing agent concentration range, it is possible to obtain high-quality treated water having low fluorine, phosphorus and chloride ion concentrations, and also to reduce the amount of sludge generated.

[0077] The seventh flocculation reaction tank 123 may be configured to add the sixth effluent and partially flocculate it to generate eighth effluent.

[0078] The seventh flocculation reaction tank 123 may be configured to operate at a polymer flocculant concentration range of 3.0±0.5 ppm. If the seventh flocculation reaction tank 123 is configured to operate at the polymer flocculant concentration range, it is possible to obtain high-quality treated water with low fluorine, phosphorus and chloride ion concentrations, and also to reduce the amount of sludge generated.

[0079] The wastewater treatment device 100 further includes a sixth coagulation reaction tank 122 configured to add the sixth treated water and partially coagulate it to produce seventh treated water between the fifth coagulation reaction tank 121 and the seventh coagulation reaction tank 123. In this case, the seventh coagulation reaction tank 123 is configured to add and treat the seventh treated water instead of the sixth treated water to produce eighth treated water.

[0080] The second settling tank 124 may be configured to partially settle the eighth effluent and produce a ninth effluent TW9 and a sludge SLG2.

[0081] Furthermore, each of the first flocculation reaction tank 111 to the seventh flocculation reaction tank 123 can be equipped with an agitator st.

[0082] 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 60% by weight, reduce the amount of sludge generated by 20% by weight, and prevent an increase in chloride ion concentration, compared to the prior art.

[0083] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to such examples.

[0084] Example: Making a device A wastewater treatment device having the configuration shown in FIG. 1 was fabricated.

[0085] The wastewater treatment device thus prepared is composed of a first coagulation / sedimentation unit and a second coagulation / sedimentation unit.

[0086] The first coagulation / 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 settling tank.

[0087] The second flocculation / sedimentation unit is composed of a fifth flocculation reaction tank, a sixth flocculation reaction tank, a seventh flocculation reaction tank and a second settling tank.

[0088] Example 1: Operation of wastewater treatment equipment The wastewater 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 The semiconductor process wastewater with -P of 160 ppm was used. The first coagulation reaction tank was charged with slaked lime, the second coagulation reaction tank was not charged with any chemicals, and the third coagulation reaction tank was charged with slaked lime and aluminum chloride (AlCl 3The amount of slaked lime added to the first flocculation reaction tank is such that the pH (R1-pH) of the first flocculation reaction tank is maintained at 3.5. The amount of aluminum chloride (AlCl) added to the third flocculation reaction tank is such that the pH (R1-pH) of the first flocculation reaction tank is maintained at 3.5. 3 The aluminum chloride (AlCl) content in the third flocculation reactor 3 The amount 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 amount of anionic polyacrylamide added to the fourth coagulation reaction tank is such that the anionic polyacrylamide concentration (R4-C3) of the fourth coagulation reaction tank is 3 ppm. The fifth coagulation reaction tank contains aluminum chloride (AlCl 3 ) and sodium aluminate (NaAlO 2 ) is added to the sixth flocculation reactor, no chemical is added to the seventh flocculation reactor, and anionic polyacrylamide is added to the seventh flocculation reactor. Sodium aluminate (NaAlO 2 The content of sodium aluminate (NaAlO 2 The aluminum chloride (AlCl) added to the fifth coagulation reactor is added in an amount such that the concentration (R5-C4) of the aluminum chloride (AlCl) is 1,425 ppm. 3 The content of anionic polyacrylamide added to the seventh flocculation reactor is an amount that allows the pH (R5-pH) of the fifth flocculation reactor to be maintained at 7.0. The content of anionic polyacrylamide added to the seventh flocculation reactor is an amount that allows the anionic polyacrylamide concentration (R7-C3) of the seventh flocculation reactor to be 3 ppm.

[0089] 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 reaction tank was changed to an amount such that the pH (R1-pH) of the first coagulation reaction tank was maintained at 5.0.

[0090] 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 reaction tank was changed to an amount such that the pH (R1-pH) of the first coagulation reaction tank was maintained at 6.0.

[0091] Example 4: Operation of wastewater treatment equipment Aluminum chloride (AlCl) added to the third coagulation reactor 3 ) content in the third flocculation reaction tank. 3 The wastewater treatment device was operated in the same manner as in Example 2, except that the concentration (R3-C2) was changed to 800 ppm.

[0092] Example 5: Operation of wastewater treatment equipment Aluminum chloride (AlCl) added to the third coagulation reactor 3 ) content in the third flocculation reaction tank. 3 The wastewater treatment device was operated in the same manner as in Example 2, except that the concentration (R3-C2) was changed to 1,700 ppm.

[0093] Example 6: Operation of wastewater treatment equipment Sodium aluminate (NaAlO 2 ) in the fifth flocculation reactor. 2 The wastewater treatment device was operated in the same manner as in Example 2, except that the concentration (R5-C4) was changed to 850 ppm.

[0094] Example 7: Operation of wastewater treatment equipment Sodium aluminate (NaAlO 2 ) in the fifth flocculation reactor. 2The wastewater treatment device was operated in the same manner as in Example 2, except that the concentration (R5-C4) was changed to 2,000 ppm.

[0095] Example 8: Operation of wastewater treatment equipment Aluminum chloride (AlCl) added to the fifth coagulation reactor 3 The wastewater treatment device was operated in the same manner as in Example 2, except that the content of 1,2-dichlorophenyl phosphate ester (1,2-dichlorophenyl phosphate) was changed to an amount such that the pH of the fifth coagulation reactor (R5-pH) was maintained at 6.5.

[0096] Example 9: Operation of wastewater treatment equipment Aluminum chloride (AlCl) added to the fifth coagulation reactor 3 The wastewater treatment device was operated in the same manner as in Example 2, except that the content of 1,2-dichlorophenyl phosphate ester (1,2-dichlorophenyl phosphate) was changed to an amount such that the pH of the fifth coagulation reactor (R5-pH) was maintained at 7.5.

[0097] 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 reaction tank was changed to an amount such that the pH (R1-pH) of the first coagulation reaction tank was maintained at 3.0.

[0098] 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 reaction tank was changed to an amount that maintained the pH (R1-pH) of the first coagulation reaction tank at 7.0.

[0099] Reference Example 3: Operation of wastewater treatment equipment Aluminum chloride (AlCl) added to the third coagulation reactor 3 ) content in the third flocculation reaction tank. 3 The wastewater treatment device was operated in the same manner as in Example 2, except that the concentration (R3-C2) was changed to 600 ppm.

[0100] Reference Example 4: Operation of wastewater treatment equipment Aluminum chloride (AlCl) added to the third coagulation reactor 3 ) content in the third flocculation reaction tank. 3 The wastewater treatment device was operated in the same manner as in Example 2, except that the concentration (R3-C2) was changed to 1,900 ppm.

[0101] Reference Example 5: Operation of wastewater treatment equipment Sodium aluminate (NaAlO 2 ) in the fifth flocculation reactor. 2 The wastewater treatment device was operated in the same manner as in Example 2, except that the concentration (R5-C4) was changed to 750 ppm.

[0102] Reference Example 6: Operation of wastewater treatment equipment Sodium aluminate (NaAlO 2 ) in the fifth flocculation reactor. 2 The wastewater treatment device was operated in the same manner as in Example 2, except that the concentration (R5-C4) was changed to 2,100 ppm.

[0103] Reference Example 7: Operation of wastewater treatment equipment Aluminum chloride (AlCl) added to the fifth coagulation reactor 3 The wastewater treatment device was operated in the same manner as in Example 2, except that the content of 1,2-dichlorophenyl phosphate ester (1,2-dichlorophenyl phosphate) was changed to an amount such that the pH of the fifth coagulation reactor (R5-pH) was maintained at 6.0.

[0104] Reference Example 8: Operation of wastewater treatment equipment Aluminum chloride (AlCl) added to the fifth coagulation reactor 3The wastewater treatment device was operated in the same manner as in Example 2, except that the content of 1,2-dichlorophenyl phosphate ester (1,2-dichlorophenyl phosphate) was changed to an amount such that the pH of the fifth coagulation reactor (R5-pH) was maintained at 8.0.

[0105] Reference Example 9: Operation of wastewater treatment equipment Aluminum chloride (AlCl) added to the third coagulation reactor 3 ) into alum (Al 2 (SO 4 ) 3 The wastewater treatment device was operated in the same manner as in Example 2, except that the alum concentration in the third coagulation reactor (R3-C2') was maintained at 900 ppm.

[0106] Reference Example 10: Operation of wastewater treatment equipment Sodium aluminate (NaAlO 2 The wastewater treatment device was operated in the same manner as in Example 2, except that the slaked lime concentration (R5-C1) in the fifth coagulation reaction tank was maintained at 1,045 ppm by replacing the slaked lime with slaked lime.

[0107] The operating conditions (pH, amount of chemicals charged, and type of chemicals) of the wastewater treatment devices in Examples 1 to 9 and Reference Examples 1 to 10 are summarized in Table 1 below. [Table 1]

[0108] Evaluation example: Performance evaluation of wastewater treatment equipment The quality of the final treated water (ie, the treated water discharged from the second settling tank) obtained by operating the wastewater treatment apparatuses of Examples 1 to 9 and Reference Examples 1 to 10 was evaluated, and the results are shown in Table 2 below. [Table 2]

[0109] Referring to Table 2, it is shown that the wastewater treatment devices of Examples 1 to 9 are superior in the quality of the final treated water compared to the wastewater treatment devices of Reference Examples 1 to 10.

[0110] 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]

[0111] 100 Wastewater treatment equipment 110,120 Coagulation and Sedimentation Unit 111~114,121~123 Coagulation reaction tank 115,124 Sedimentation tank C1~C4 Drugs SLG1,SLG2 Sludge TW5, TW9 treated water WW Wastewater

Claims

1. The method includes a first flocculation / sedimentation step and a second flocculation / sedimentation step which are carried out successively, The first coagulation and precipitation step includes: A step (S10-2) of passing 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 flocculation reactor to generate tertiary treated water; (S10-6) passing the tertiary effluent through a fourth flocculation reactor to generate a fourth effluent; and (S10-8) passing the quaternary effluent through a first settling tank to generate quinary effluent and sludge; The second coagulation and precipitation step includes: (S20-2) passing the fifth effluent through a fifth flocculation reactor to generate sixth effluent; (S20-4) passing the sixth effluent through a seventh flocculation reactor to generate eighth effluent; and (S20-6) passing the eighth effluent through a second settling tank to produce a ninth effluent and sludge.

2. 2. The wastewater treatment method according to claim 1, wherein a first chemical is added to the first coagulation reaction tank, a first chemical and a second chemical are added to the third coagulation reaction tank, a third chemical is added to the fourth coagulation reaction tank, a second chemical and a fourth chemical are added to the fifth coagulation reaction tank, and a third chemical is added to the seventh coagulation reaction tank.

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

4. The chlorine-based fluorine remover is aluminum chloride (AlCl ３ ), the polymer flocculant comprises anionic polyacrylamide, sodium alginate, sodium polyacrylate, maleic acid copolymer, partial hydrolyzate of polyacrylamide, or a combination thereof, and the alkaline fluoride removing agent comprises sodium aluminate (NaAlO ２ 4. The wastewater treatment method according to claim 3, comprising:

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

5.

6. 6. The wastewater treatment method according to claim 5, wherein the pH of the third flocculation reaction tank is adjusted to a 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 flocculation reaction tank is adjusted to a range of 3.0±0.5 ppm, and the concentration of the third chemical in the seventh flocculation reaction tank is adjusted to a range of 3.0±0.5 ppm.

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

9. 2. The wastewater treatment method according to claim 1, further comprising a step (S10-3) between steps (S10-2) and (S10-4) of passing the primary treated water through a second coagulation reaction tank to produce secondary treated water, in which case step (S10-4) is a step of passing the secondary treated water through the third coagulation reaction tank instead of the primary treated water to produce tertiary treated water.

10. The method for treating wastewater according to claim 9, wherein no chemicals are separately added to the second flocculation reaction tank.

11. 2. The wastewater treatment method of claim 1, further comprising a step (S20-3) between steps (S20-2) and (S20-4) of passing the sixth effluent through a sixth flocculation reaction tank to produce seventh effluent, in which case step (S20-4) is a step of passing the seventh effluent through the seventh flocculation reaction tank instead of the sixth effluent to produce eighth effluent.

12. The method for treating wastewater according to claim 11, wherein no chemicals are separately added to the sixth flocculation reaction tank.

13. The method includes the steps of: connecting a first flocculation / sedimentation unit and a second flocculation / sedimentation unit in series; The first flocculation / sedimentation unit comprises: a first flocculation reaction tank configured to partially flocculate wastewater containing at least fluorine and phosphorus to produce a primary effluent; a third flocculation reactor configured to add and partially flocculate the primary effluent to produce a tertiary effluent; a fourth flocculation reactor configured to add the tertiary effluent and partially flocculate it to produce a fourth effluent; a first settling tank configured to partially settle the quaternary effluent and produce a quinary effluent and a sludge; The second flocculation / sedimentation unit comprises: A fifth flocculation reaction tank configured to add the fifth effluent and partially flocculate it to produce sixth effluent; A seventh flocculation reaction tank configured to add the sixth effluent and partially flocculate it to produce an eighth effluent; a second settling tank configured to partially settle the 8th effluent and produce a 9th effluent and a sludge.

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

5.

15. 15. The wastewater treatment apparatus of claim 14, wherein the third flocculation reactor is configured to operate with a pH range of 7.0±0.

5.

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

17. 16. The wastewater treatment device according to claim 15, wherein the third coagulation reaction tank is configured to be operated with a chlorine-based fluoride removing agent concentration range of 800 to 1,700 ppm, and the fifth coagulation reaction tank is configured to be operated with an alkali-based fluoride removing agent concentration range of 850 to 2,000 ppm.

18. 14. The wastewater treatment device according to claim 13, further comprising a second coagulation reaction tank between the first coagulation reaction tank and the third coagulation reaction tank, the second coagulation reaction tank being configured to add and treat the primary treated water, instead of the primary treated water, to produce tertiary treated water.

19. The wastewater treatment apparatus according to claim 18, wherein no chemical is separately added to the second flocculation reaction tank.

20. 14. The wastewater treatment device according to claim 13, further comprising a sixth coagulation reaction tank between the fifth coagulation reaction tank and the seventh coagulation reaction tank, configured to add the sixth effluent water to partially coagulate it and produce seventh effluent water, in which case the seventh coagulation reaction tank is configured to add and treat the seventh effluent water instead of the sixth effluent water to produce eighth effluent water.

21. The wastewater treatment apparatus according to claim 20 , wherein no chemical is separately added to the sixth flocculation reaction tank.

Images