KR-20260066659-A - Drainage treatment facilities and drainage treatment methods

Abstract

This wastewater treatment facility is equipped with a first pH adjustment facility that adjusts the pH to 10 to 12 by adding an alkali agent to wastewater containing heavy metals, a filtration facility that separates and removes precipitates precipitated by pH adjustment in the first pH adjustment facility using a filtration device, a second pH adjustment facility that adjusts the pH to 9.5 to 11 by adding an acid to the treated water after filtration discharged from the filtration facility, and a reverse osmosis treatment device that reverse osmosis treats the treated water pH-adjusted in the second pH adjustment facility using a reverse osmosis membrane.

Inventors

• 고토 히데키

Assignees

• 쿠리타 고교 가부시키가이샤

Dates

Publication Date

20260512

Application Date

20240723

Priority Date

20230913

Claims (10)

1. A first pH adjustment facility that adjusts the pH to 10 to 12 by adding an alkaline agent to wastewater containing heavy metals, and A filtration facility that separates and removes the precipitate precipitated by pH adjustment in the first pH adjustment facility by a filtration device, and A second pH adjustment facility that adds acid to the treated water discharged from the above filtration facility after filtration to adjust the pH to 9.5 to 11, and A reverse osmosis treatment device that processes the pH-adjusted treated water from the above-mentioned second pH adjustment facility using a reverse osmosis membrane. A drainage treatment facility equipped with
2. In paragraph 1, A wastewater treatment facility further equipped with a third pH adjustment facility that adds acid to the permeate discharged from the above reverse osmosis membrane treatment device to adjust the pH to 5.8 to 8.6.
3. In paragraph 2, A drainage treatment facility further equipped with a supply path for supplying pH-adjusted treated water from the above-mentioned third pH adjustment facility as facility water.
4. In any one of paragraphs 1 through 3, A backwashing facility for backwashing the filtration device provided in the above filtration facility, and A coagulation sedimentation facility for coagulating and sedimentating the cleaning wastewater discharged from the above-mentioned backwashing facility, and A wastewater treatment facility further equipped with a first return path that supplies the treated water discharged from the above-mentioned coagulation sedimentation facility to the above-mentioned first pH adjustment facility.
5. In paragraph 4, A dewatering treatment facility for dewatering sludge generated in the above-mentioned coagulation and sedimentation facility, and A wastewater treatment facility further equipped with a second return path for returning the dewatered treated water separated from the sludge in the dewatering treatment facility to the coagulation sedimentation facility.
6. A first pH adjustment process for adjusting the pH to 10 to 12 by adding an alkaline agent to wastewater containing heavy metals, and A filtration process for separating and removing precipitates precipitated by a first pH adjustment process using a filtration device, and A second pH adjustment process of adding acid to the treated water after the above filtration process to adjust the pH to 9.5 to 11, and A reverse osmosis treatment process in which the treated water after the above second pH adjustment process is treated by a reverse osmosis membrane. This equipped drainage treatment method.
7. In paragraph 6, A wastewater treatment method further comprising a third pH adjustment process for adjusting the pH to 5.8 to 8.6 by adding acid to the permeate after the above reverse osmosis membrane treatment process.
8. In Paragraph 7, A wastewater treatment method for supplying the treated water after the above-mentioned third pH adjustment process to the supply path of the facility water.
9. In any one of paragraphs 6 through 8, A backwashing process for backwashing the filtration device used in the above filtration process, and A coagulation sedimentation process for treating the cleaning wastewater after the above backwashing process with coagulation sedimentation, and A wastewater treatment method further comprising a first return process for supplying the treated water after the above coagulation and sedimentation process to the above first pH adjustment process.
10. In Paragraph 9, A dewatering treatment process for dewatering the sludge generated by the above-mentioned coagulation and sedimentation process, and A wastewater treatment method further comprising a second return process for returning the dewatered treated water separated from the sludge in the above dewatering treatment process to a coagulation sedimentation process.

Description

Drainage treatment facilities and drainage treatment methods The present invention relates to a wastewater treatment facility and a wastewater treatment method. The present application claims priority based on Japanese Patent Application No. 2023-148051 filed in Japan on September 13, 2023, and incorporates the contents thereof herein. When treating wastewater containing heavy metals such as Ni and Cu, generally, the pH of the wastewater is adjusted to about 10 to 12 to precipitate and coagulate the heavy metals contained in the wastewater as hydroxides, and then the wastewater is treated by undergoing a sedimentation or filtration process. The treated water after filtration is discharged after neutralization treatment is performed. However, there are cases where part or all of this effluent is reused as water for facilities such as, for example, a cooling tower (hereinafter referred to as CT). In this case, depending on the quality of the effluent, it is necessary to perform desalination or filtration treatment on the effluent using a reverse osmosis membrane or other microfiltration membrane. However, if the organic matter concentration of the effluent is high, supplying it directly to the reverse osmosis membrane or microfiltration membrane may cause biofouling and reduce the permeation flow rate of these membranes. Therefore, it is necessary to supply the effluent to the reverse osmosis membrane or microfiltration membrane while suppressing biofouling by readjusting the pH of the effluent to, for example, 9 to 11. In addition, Patent Document 1 describes a method for treating wastewater from a wet flue gas desulfurization device, comprising a reaction process for precipitating heavy metals, fluorine, calcium, magnesium, etc. as solids by treating the wastewater from the wet flue gas desulfurization device with alkali and softening, a first solid-liquid separation process for separating solids generated in the reaction process from the wastewater, a second solid-liquid separation process for separating fine solids contained in the wastewater using a fine filtration membrane while adjusting the pH of the wastewater treated in the first solid-liquid separation process, and a salt separation process for separating salts dissolved in the wastewater treated in the second solid-liquid separation process using a reverse osmosis membrane, wherein the water recovered from the salt separation process is circulated and reused in the flue gas desulfurization device. FIG. 1 is a schematic diagram showing the configuration of a wastewater treatment facility, which is an embodiment of the present invention. Hereinafter, a wastewater treatment facility and a wastewater treatment method that are embodiments of the present invention will be described. FIG. 1 shows a schematic diagram of the configuration of a wastewater treatment facility that is an embodiment of the present invention. As shown in FIG. 1, the wastewater treatment facility (1) of the present embodiment is equipped with at least a heavy metal treatment facility (3), a second pH adjustment facility (5), and a reverse osmosis membrane treatment device (7). The heavy metal treatment facility (3) consists of a first pH adjustment facility (3A) and a filtration facility (3B). In addition, a backwashing facility (3B2) is provided in the filtration facility (3B). A backwashing drainage tank (12) is connected to the filtration facility (3B). In addition, the wastewater treatment facility (1) shown in FIG. 1 is equipped with a raw water tank (2), a filtered water tank (4), and an RO supply tank (6). The raw water tank (2) is installed upstream of the heavy metal treatment facility (3). The filtered water tank (4) is positioned between the heavy metal treatment facility (3) and the second pH adjustment facility (5). The RO supply tank (6) is positioned between the second pH adjustment facility (5) and the reverse osmosis membrane treatment device (7). In addition, in the wastewater treatment facility (1) shown in FIG. 1, a third pH adjustment facility (8) and a recovery treatment tank (9) are arranged at the rear end of the reverse osmosis membrane treatment device (7). A supply path (L1) is connected to the recovery treatment tank (9). The supply path (L1) is connected to various facilities or equipment that allow the treatment water to be reused. Examples of such facilities or equipment include a cooling tower, a boiler, and a cleaning facility. In addition, the third pH adjustment facility (8) is configured so that permeate water from the treatment water treated by the reverse osmosis membrane treatment device (7) flows into it. Additionally, a fourth pH adjustment facility (10) and a discharge tank (11) are arranged at the rear end of the reverse osmosis membrane treatment device (7). The fourth pH adjustment facility (10) is configured to receive the concentrated water separated by the reverse osmosis membrane treatment device (7). In addition, the wastewater tr