KR102250903B1 - Treatment System of The Wastewater Containing Silica Capable of removing nitrogen and Phosphorus - Google Patents

Abstract

The present invention is a first gravity sedimentation tank (10) for the silica-containing wastewater is introduced to remove the primary precipitation of silica; A second gravity settling tank 20 installed at a rear end of the first gravity settling tank to precipitate and remove residual silica contained in the treated water; A membrane separation aerobic tank 30 installed at the rear end of the second gravity settling tank and performing solid-liquid separation and nitrification of the treated water by aeration treatment of the introduced treated water; A degassing tank 40 installed at the rear end of the aerobic tank to reduce dissolved oxygen contained in the treated water; And a reaction tank 50 that receives the treated water returned from the degassing tank and performs nitrification and denitrification contained in the treated water.
According to the present invention as described above, it is possible not only to effectively treat silica generated in semiconductors, especially wafer processes, but also to treat organic substances contained in sewage and nutrients such as nitrogen and phosphorus at the same time.

Description

Silica Capable of Removing Nitrogen and Phosphorus {Treatment System of The Wastewater Containing Silica Capable of Removing Nitrogen and Phosphorus}

The present invention relates to an apparatus for treating wastewater containing silica, and more particularly, to effectively treat wastewater containing silica generated in a semiconductor process, particularly a wafer process, as well as organic substances and nutrients contained in various wastewater. It relates to an apparatus for treating wastewater containing silica capable of simultaneously treating phosphorus nitrogen and phosphorus.

Various construction methods and facilities are being researched and operated in the field for the treatment of wastewater generated in industrial facilities. As a conventional technique for the treatment of wastewater and sewage generated in a semiconductor manufacturing process, reference may be made to Patent No. 0385706.

Patent No. 0385706 discloses a method and system for removing silica from a large amount of wastewater. According to the method, the wastewater stream containing silica is treated with a flocculant such as epichlorohydrin/dimethylamine polymer, resulting in clustered spherical particles having a diameter of 5 microns or more. At this time, the treated wastewater is passed through a microfiltration membrane that physically separates the silica contaminant particles from the wastewater. For this, commercially available microfiltration membranes having a pore size of 0.5 microns to 5 microns can be used. The flow rate of the treated wastewater passing through the microfiltration membrane is 150 GFD (gallons per square foot of membrane per day) to 600 GFD, and to maintain this, the microfiltration membrane is periodically backwashed and the filtration vessel with the membrane is intermittently drained. This should ensure that solids are removed from the surface of the membrane.

However, it is pointed out that in general, wastewater generated in a semiconductor manufacturing process has a high concentration of suspended solids (SS), and a phenomenon in which the differential pressure increases due to membrane contamination during the treatment process. This phenomenon is caused by _{silica (SiO 2} ) discharged from the semiconductor wafer (Wafer) process.

However, the existing silica-containing wastewater has difficulties such as taking a lot of cost and time in actual operation, such as having to be cleaned or replaced from time to time using a method such as backwashing due to problems such as membrane contamination as described above. Moreover, wastewater generated from various business sites in industrial complexes includes not only wastewater containing silica, but also organic substances from various sewage and substances that cause eutrophication such as nitrogen and phosphorus to pollute the water quality environment. It cannot be solved by the facility alone, and a separate treatment facility is required. This also requires additional cost and time.

Therefore, development of technology that can effectively treat wastewater containing silica generated in semiconductor processes, especially wafer processes, as well as simultaneously treat organic substances and nutrients nitrogen and phosphorus contained in various wastewater mixed with copper wastewater. This is in desperate need.

[Prior technical literature]

[Patent Literature]

Korean Patent Publication No. 10-0385706 (2003.05.16)

Accordingly, the present invention has been devised to solve the above problems, and effectively treats wastewater containing silica generated in semiconductor processes, especially wafer processes, as well as organic substances and nutrients contained in various wastewaters. It is an object to provide an apparatus for treating wastewater containing silica capable of simultaneously treating phosphorus nitrogen and phosphorus.

The technical problem of the present invention as described above is achieved by the following means.

(1) a first gravity sedimentation tank in which silica-containing wastewater is introduced and the silica is first precipitated and removed; A second gravity settling tank installed at a rear end of the first gravity settling tank to precipitate and remove residual silica contained in the treated water; A membrane separation aerobic tank installed at the rear end of the second gravity sedimentation tank and performing solid-liquid separation and nitrification of the treated water by aeration treatment of the introduced treated water; A degassing tank installed at the rear end of the aerobic tank to reduce dissolved oxygen contained in the treated water; And a reaction tank that receives the treated water returned from the degassing tank and performs nitrification and denitrification contained in the treated water.

(2) In the above (1),

The reaction tank is a treatment apparatus for silica-containing wastewater, characterized in that the reaction tank receives the inflow of the treated water returned through the degassing tank and is operated alternately in the order of anaerobic, aerobic, and anaerobic using an intermittent aeration method.

(3) In the above (1),

Silica-containing wastewater treatment devices are installed in parallel in a pair, and for this purpose, a distribution tank is installed at the front end of the wastewater inflow, and the distribution tank receives raw water (or treated water that has undergone pretreatment) from the outside and a pair of left and right sides thereof. Silica-containing wastewater treatment apparatus, characterized in that distributed to the first gravity settling tank of.

(4) In the above (3),

One of the pair of reaction tanks is set as the time to receive the treated water in an anaerobic state from the degassing tank, and the other is to perform an alternating reaction of anaerobic, aerobic, and anaerobic treatment water to alternate the process cycle of the reaction tank. Silica-containing wastewater treatment apparatus, characterized in that configured to be able to.

(5) In the above (3),

A device for treating wastewater containing silica, characterized in that a scum storage tank is provided at a rear end of the degassing tank to remove scum prior to discharge of the final treated water.

(6) In the above (1),

The reactor is a silica-containing wastewater treatment apparatus, characterized in that the first reaction chamber for anaerobic and aerobic processes and a second reaction chamber for subsequent anaerobic processes are separately installed.

(7) In the above (6),

An apparatus for treating wastewater containing silica, characterized in that a connection pipe is provided between the first reaction chamber and the second reaction chamber, and a heat supply means is additionally mounted on the connection pipe.

(8) In the above (6),

An apparatus for treating wastewater containing silica, characterized in that a vacuum pump is connected to the outside with a sealed structure for vacuum depressurization at an upper portion of the second reaction chamber.

(9) In the above (8),

Silica-containing wastewater, characterized in that a heat supply means is installed in the connection pipe between the degassing tank and the membrane separation aerobic tank to supply heat to the treated water, and a vacuum pump is connected to the outside with a sealed structure for vacuum depressurization at the top of the degassing tank. Processing device.

(10) In (9) above,

An apparatus for treating wastewater containing silica, characterized in that a baffle having a hemispherical protrusion formed on its surface is mounted inside the first gravity settling tank and the second gravity settling tank.

As described above, the device according to the present invention is a very useful and effective invention that can effectively treat silica generated in semiconductors, especially wafer processes, as well as organic substances contained in sewage and nutrients such as nitrogen and phosphorus. .

1 is a view showing an apparatus for treating wastewater containing a kirka according to the present invention,
Figure 2 is a view showing the configuration of the gravity settling tank according to the present invention.
3 is a view showing a preferred embodiment of the reaction tank according to the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. DETAILED DESCRIPTION OF THE INVENTION The detailed description to be disclosed below together with the accompanying drawings is intended to describe exemplary embodiments of the present invention, and is not intended to represent the only embodiments in which the present invention may be practiced. The following detailed description includes specific details to provide a thorough understanding of the present invention. However, those of ordinary skill in the art to which the present invention pertains knows that the present invention may be practiced without these specific details.

In some cases, in order to avoid obscuring the concept of the present invention, well-known structures and devices may be omitted, or may be illustrated in a block diagram form centering on core functions of each structure and device.

Throughout the specification, when a part is said to "comprising or including" a certain component, it means that other components may be further included rather than excluding other components unless specifically stated to the contrary. do. In addition, the term "... unit" described in the specification means a unit that processes at least one function or operation. In addition, "a or an", "one", "the" and similar related words are different from the present specification in the context of describing the present invention (especially in the context of the following claims). Unless indicated or clearly contradicted by context, it may be used in the sense of including both the singular and the plural.

In describing the embodiments of the present invention, if it is determined that a detailed description of a known function or configuration may unnecessarily obscure the subject matter of the present invention, a detailed description thereof will be omitted. In addition, terms to be described later are terms defined in consideration of functions in an embodiment of the present invention, which may vary according to the intention or custom of users or operators. Therefore, the definition should be made based on the contents throughout the present specification.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a view showing an apparatus for treating wastewater containing silica according to the present invention, FIG. 2 is a view showing the configuration of a gravity settling tank according to the present invention, and FIG. 3 is a diagram showing a preferred embodiment of a reaction tank according to the present invention. It is a drawing.

As shown in the drawing, the silica-containing wastewater treatment apparatus 100 includes: a first gravity settling tank 10 for primary precipitation and removal of silica by introducing the silica-containing wastewater; A second gravity settling tank 20 installed at a rear end of the first gravity settling tank and for sedimenting and removing residual silica contained in the treated water; A membrane separation aerobic tank 30 installed at the rear end of the second gravity settling tank and performing solid-liquid separation and nitrification of the treated water by aeration treatment of the introduced treated water; A degassing tank 40 installed at the rear end of the aerobic tank to reduce dissolved oxygen contained in the treated water; And a reaction tank 50 that receives the treated water returned from the degassing tank and performs nitrification and denitrification contained in the treated water.

Preferably, the silica-containing wastewater treatment apparatus 100 according to the present invention is installed in parallel in a pair. For this purpose, a distribution tank 60 is installed at the foremost end of which wastewater is introduced. The distribution tank 60 receives raw water (or treated water that has undergone pretreatment) introduced from the outside and distributes it to a pair of left and right first gravity settling tanks 10. A pressure flotation tank (not shown) may be installed at the front end of the distribution tank 60 for pretreatment to remove various floating matters including fats and oils contained in the raw water in advance.

At this time, the distribution may be made in consideration of the processing capacity of each device and the operating state of the facility, and it is preferable to be automatically controlled through a controller (not shown). For example, the distribution tank 60 controls to inflow raw water to the other when a factor such as replacement or repair occurs in one facility.

A baffle 11 is formed inside the first gravity settling tank 10 to induce particles including silica to settle by gravity. At this time, the amount of silica to be removed is about 30 to 60%.

Preferably, hemispherical projections (not shown) are formed on the surface of the baffle at regular intervals. The hemispherical protrusion prevents the formation of a cake by preventing the formation of a cake by preventing the floating matter in the wastewater from agglomeration, and as a result, it is possible to increase the recovery or removal efficiency of silica.

The treated water that has passed through the first gravity settling tank 10 flows into the second gravity settling tank 20. In the second gravity settling tank 20, the baffle 21 is mounted on the inside so as to be perpendicular to the traveling direction of the treated water. Accordingly, most of the remaining silica particles contained in the treated water being moved can be blocked by the baffle 21 and precipitated by gravity and removed.

The treated water that has passed through the second gravity settling tank 20 is in a state in which silica particles are almost removed. Therefore, according to the present invention, it is possible to prevent contamination of the separation membrane installed in the membrane separation aerobic tank 30 installed at the rear end.

The membrane separation aerobic tank 30 performs solid-liquid separation and nitrification of the treated water, and phosphorus intake occurs along with it. The separation membrane 31 immersed inside is preferably a hollow fiber precision filtration membrane, and can be cleaned using only aeration air without the need for a backwashing process of water, air, and chemicals, so it is possible to operate the membrane for more than 6 months. .

In addition, in the present invention, since the suction filtration hollow fiber microfiltration membrane is used in place of the existing sedimentation tank, filtration tank, and disinfection tank for nitrification and phosphorus removal as described above, operation of the process is performed at an MLSS concentration of about 7,000 to 13,000 mg/L. As it is possible, there is no need for separate injection of chemicals to remove phosphorus, and stable nitrification is possible even in winter.

The degassing tank 40 reduces dissolved oxygen contained in the treated water that has passed through the membrane separation aerobic tank 30 at the front end. The degassing tank 40 is not supplied with separate compressed air, and can be simply performed through stirring. Since the treated water discharged through the membrane separation aerobic tank 30 contains a large amount of dissolved oxygen, the degassing tank 40 consumes such dissolved oxygen to oxidize and remove organic substances present in the treated water, and through this, dissolved oxygen in the treated water. Is reduced.

As described above, the anaerobic atmosphere performed in the reaction tank 50 at the rear stage is provided through the reduction of dissolved oxygen by the degassing tank 40. Preferably, the dissolved oxygen in the treated water passing through the degassing tank 40 is 0.2 mg/L or less.

The treated water from the degassing tank 40 is returned to the reaction tank 50.

The reaction tank 50 receives the recirculated treated water through the degassing tank 40 and is operated alternately in the order of anaerobic, aerobic, and anaerobic processes, preferably using an intermittent aeration method. Therefore, the treated water passing through the degassing tank 40 is first operated in an anaerobic process, and during this period, denitrification of the treated water and release of phosphorus are induced. Subsequently, the treated water is passed to an aerobic process, through which the residual nitrogen is nitrified. Then, the nitrate nitrogen produced through the nitrification process is subjected to a denitrification and phosphorus removal process in an anaerobic atmosphere again by a subsequent anaerobic process. The series of processes may be performed by a simple method of intermittently aeration sequentially in one reaction chamber.

In a preferred embodiment of the present invention, the reaction tank 50 is preferably a first reaction chamber 51 for anaerobic and aerobic processes in order to efficiently create the anaerobic atmosphere of the last stage, and a second reaction chamber for the last anaerobic process. The reaction chamber 52 can be installed separately. In this case, preferably, a connection pipe 53 is provided between the first reaction chamber 51 and the second reaction chamber 52, and a heat supply means 54 may be additionally mounted on the connection pipe. The heat supply means may be a heat exchanger that receives heat through a heat exchange method from a high-temperature fluid supplied from a heating jacket or a boiler that surrounds a part of the connection pipe. In addition, a vacuum pump (not shown) may be connected to an upper portion of the second reaction chamber 52 with a sealed structure for vacuum pressure reduction.

According to this configuration, since anaerobic and aerobic reactions must occur in succession in the first reaction chamber 51, an acidic means is required in the lower part of the first reaction chamber, and an aerobic reaction proceeds through aeration treatment after the anaerobic reaction. I can make it. The treated water in which the aerobic reaction has progressed contains dissolved oxygen, which is heated by a heat supply means before flowing into the second reaction chamber 52 (preferably, the temperature of the treated water is raised to reach 30 to 40°C. ), the heated treated water is introduced into the second reaction chamber 52 to reduce the oxygen solubility due to the increase in temperature, and if the vacuum pump is operated to maintain a reduced pressure at the top, the oxygen solubility is further reduced. Most of the dissolved oxygen can be removed in a short time. By this process, the second reaction chamber 52 can be formed in an anaerobic atmosphere in a short time.

As described above, the operation of the heat supply means 54 or the vacuum pump may be controlled by a controller (not shown).

Through this series of reactions, most of the nitrogen and phosphorus compounds present in the treated water can be removed. The treatment process through the reaction tank 50 may be operated for 60 minutes in general.

In the present invention, preferably, the reaction tank 50 is maintained in an anaerobic atmosphere for a period of time (set to about 60 minutes) that the treated water is introduced from the degassing tank 40 before starting a series of reactions of anaerobic, aerobic, and anaerobic processes. .

As a preferred embodiment of the present invention, one of the pair of reaction tanks 50 is set as the time to receive the treated water in an anaerobic state from the degassing tank 40, and the other is the anaerobic, aerobic, and anaerobic process for the introduced treated water. By allowing a series of reactions to be performed, the process cycles of the reactor can be carried out alternately.

In the present invention, since it is abandoned using the intermittent aeration method as described above, it is possible to reduce maintenance costs by having its own sludge conveyance effect.

The treated water that has passed through the reaction tank 50 as described above is again introduced into the membrane separation aerobic tank 30 to oxidize and remove organic substances that may remain in the treated water, while complete nitrification and phosphorus removal are achieved. The treated water that has passed through the membrane separation aerobic tank 30 flows into the degassing tank 40 to reduce dissolved oxygen, and part of the treated water is returned to the reaction tank 50 through the return line, and the rest is returned to the scum storage tank 70. After removing the scum through the process, it is discharged.

Preferably, heat supply means such as a heating jacket or a heat exchanger are placed in the connection pipe (not shown) between the degassing tank 40 and the membrane separation aerobic tank 30 as in the reaction tank, and vacuum depressurization at the top of the degassing tank 40 A vacuum pump 55 is connected to the outside with a sealed structure for. Through this, dissolved oxygen can be almost completely reduced during a short residence time in the degassing tank, thereby improving treatment efficiency.

Hereinafter, the content of the present invention will be described in more detail with reference to examples. However, the examples illustrated below are provided to aid understanding of the present invention and should not be construed as limiting the scope of the present invention.

[Example 1]

As a result of conducting an experiment on wastewater generated in the Asan Digital Industrial Complex, which is known to contain a large amount of silica using the apparatus of the present invention, the daily average TMS measurement values are shown in Table 1 below. However, on 2018.04.10. and 2018.04.11., it was performed by the existing treatment method (MBR method), and from 2018.04.12., the method was changed and the test was performed using the treatment apparatus according to the present invention shown in FIG. Performed.

Measurement date COD T-N T-P pH SS Comparative example 2018.04.02 7.2 1.57 0.049 7.75 41.2 2018.04.11 8.3 1.42 0.049 7.82 27.7 Example 2018.04.12 9.7 1.27 0.049 7.93 5.4 2018.04.21 6.8 1.26 0.031 7.84 0.5

As described above, it can be seen that the conventional MBR method alone does not effectively remove the suspended matter (SS) including silica, whereas the improved method according to the present invention can confirm that silica is completely removed.

10: first gravity settling tank
20: second gravity settling tank
30: membrane separation aerobic tank
40: degassing tank
50: reaction tank
60: distribution tank
70: scum storage tank

Claims (3)

A first gravity sedimentation tank in which silica-containing wastewater flows into and removes silica by primary precipitation; A second gravity settling tank installed at a rear end of the first gravity settling tank to precipitate and remove residual silica contained in the treated water; A membrane separation aerobic tank installed at the rear end of the second gravity sedimentation tank and performing solid-liquid separation and nitrification of the treated water by aeration treatment of the introduced treated water; A degassing tank installed at the rear end of the aerobic tank to reduce dissolved oxygen contained in the introduced treated water; A reaction tank for receiving the treated water returned from the degassing tank and performing nitrification and denitrification contained in the treated water; And a scum storage tank installed at the rear end of the degassing tank to remove scum prior to discharge of the final treated water,
The first gravity settling tank, the second gravity settling tank, the membrane separation aeration tank, the degassing tank, and the reaction tank are installed in parallel in a pair of left and right so as to be symmetric, and for this purpose, a distribution tank is installed at the foremost end of which wastewater is introduced, and the distribution tank is external. The raw water or pre-treated treated water is received from and distributed to the left and right pair of first gravity settling tanks,
In the reaction tank, a first reaction chamber for anaerobic and aerobic processes and a second reaction chamber for subsequent anaerobic processes are separately installed,
One of the reaction tanks is set as the time to receive the treated water in an anaerobic state from the degassing tank, and the other is to perform an alternating reaction of anaerobic, aerobic, and anaerobic treatment water to alternate the process cycle of the reaction tank. Silica-containing wastewater treatment apparatus, characterized in that configured to be. The method of claim 1,
An apparatus for treating wastewater containing silica, characterized in that a connection pipe is provided between the first reaction chamber and the second reaction chamber, and a heat supply means is additionally mounted on the connection pipe. delete

Images