KR102053795B1 - A treatment method of waste water discharged from a desulfurization tower - Google Patents

Abstract

The present invention relates to a method for treating wastewater discharged from a desulfurization tower, and more particularly, to a method for treating wastewater by removing contaminants in wastewater discharged from a desulfurization tower so as to be suitable for discharge water quality standards. To this end, the wastewater treatment apparatus includes an SS removal unit for removing insoluble solids (SS) suspended in the water to be discharged from the desulfurization tower; A COD removal unit disposed at a rear end of the SS removal unit to remove chemical oxygen demand (COD) of the water to be treated; A fluorine and heavy metal removal unit disposed at a rear end of the COD removal unit and removing fluorine and heavy metals contained in the water to be treated with COD removed; A calcium removal unit disposed at the rear of the fluorine and heavy metal removal unit to remove calcium contained in the water to be treated; A nitrogen removal unit disposed at a rear end of the calcium removal unit and configured to separate and remove nitrogen contained in the water to be treated in the form of a salt; And a flow rate control unit disposed between the calcium removing unit and the nitrogen removing unit and determining a flow rate of the treated water to be discharged and the treated water to be transferred to the nitrogen removing unit by measuring the degree of contamination of the treated water. It is done.

Description

Treatment method of wastewater discharged from desulfurization tower {A TREATMENT METHOD OF WASTE WATER DISCHARGED FROM A DESULFURIZATION TOWER}

The present invention relates to a method for treating wastewater discharged from a desulfurization tower, and more particularly, to a wastewater treatment method capable of purifying contaminants in a wastewater discharged from a desulfurization tower so as to be suitable for discharge water quality standards.

With the recent development of the industry and the improvement of life, the amount of fossil fuels required to produce electricity is being consumed more and more as the power usage increases significantly every year.

One of the main pollutants generated when burning coal, fossil fuels, is SO ₂ , and the typical content of SO ₂ in flue gas ranges from 500 to 2000 ppm. The SO ₂ is a cause of acid rain directly affects the human body, and has a huge impact on flora and fauna.

In general, desulfurization wastewater contains a large amount of NS compounds due to the emission of NO _x and SO _x when operating a thermal power plant, and high concentrations of chlorine ions, toxic substances, hardness substances (calcium ions, magnesium ions) and nitrogen. It is contained.

Conventionally, in order to treat desulfurized wastewater of this nature, the Japanese M method is used, but the M method has a problem of complicated process, difficulty in maintenance, and high operating cost. In particular, the M method is difficult to operate a bioreactor due to the high concentration of chlorine ions and toxin components in the desulfurized wastewater, and does not sufficiently cope with the removal of nitrogen components.

In order to remove nitrogen components, methods using reverse osmosis, ion exchange resins, etc. have been developed, but these methods also do not sufficiently remove nitrogen components.

On the other hand, reducing the capital expenditure (CAPEX) and operating expenses (OPEX) is one of the major challenges in operating the wastewater treatment system. For this purpose, it is important to operate the treatment plant most economically.

Therefore, there is a need to develop wastewater treatment facilities and wastewater treatment methods that can remove CAPEX and OPEX, as well as remove hard substances and nitrogen components contained in the wastewater discharged from the desulfurization tower in accordance with the discharge water quality standards. .

Republic of Korea Patent Publication No. 10-2017-0078241

The present invention is to solve the above problems, an object of the present invention to provide a wastewater treatment method that can effectively reduce the CAPEX and OPEX while purifying the wastewater discharged from the desulfurization tower to meet the discharge water quality standards. have.

These and other objects and advantages of the present invention will become apparent from the following description of preferred embodiments.

One embodiment of the present invention for achieving the problems and the problem to be solved in the prior art is a wastewater treatment method, the insoluble solids (suspended solids (SS) suspended in the treated water discharged from the desulfurization tower) SS removal step of removing; After the SS removing step, removing the chemical oxygen demand (COD) of the water to be treated; After the COD removal step, a fluorine and heavy metal removal step of removing fluorine and heavy metals contained in the COD-removed treated water; After the fluorine and heavy metal removal step, removing calcium contained in the water to be treated; After the calcium removal step, nitrogen removal step of separating and removing the nitrogen contained in the water to be treated in the form of a salt; And a flow rate control step of determining a flow rate of the treated water to be discharged and the treated water to be transferred to the nitrogen removing step by measuring the degree of contamination of the treated water between the calcium removing step and the nitrogen removing step.

At this time, the nitrogen removal step may be carried out by a falling film evaporator and a forced circulation evaporator, the forced circulation evaporator, the concentrated water introduced into the evaporation under reduced pressure to discharge the steam generated through the upper steam outlet A chamber provided with an inner space to discharge the concentrated water through the lower concentrated water outlet; A concentrated water inlet for injecting concentrated water connected to a side of the chamber in a tangential direction of the inner circumferential surface of the chamber so that the concentrated water rotates in a swirling direction along the inner circumferential surface of the chamber; And at least one partition wall provided in an area between the concentrated water inlet and the vapor outlet of the chamber internal space and protruding from the inner wall of the chamber to prevent the rising of the mist contained in the generated steam. .

The mixing step of mixing the treated water discharged and determined by the nitrogen removal unit in the flow rate control step; mixing may be further included; in this mixing step, the discharged treated water and the nitrogen removal unit The treated water from which nitrogen has been removed may be introduced and mixed through different inlets, and the treated water thus determined and the treated water removed from nitrogen by the nitrogen removing unit may be mixed while forming a swirl flow. It is preferable.

In addition, the mixing step may be further performed by a stirrer.

A plurality of evaporation tubes are provided inside the falling film evaporator, and the water to be processed may be evaporated by heat exchange with hot steam supplied to the outer wall side of the evaporation tube while flowing through the inner wall of the evaporation tube. .

The forced circulation evaporator is provided in any one or more of the upper and lower regions of the partition wall in the chamber, and is a mesh-type plate-shaped member for blocking droplets contained in the steam while the generated steam is discharged upward. It may further include a built-in demister (demister).

The forced circulation evaporator is provided so that the discharged steam is connected to the end of the steam outlet to the outside of the chamber, and the chevron type member for blocking the droplet contained in the steam is introduced on the movement path of the steam. It may further include an external demister provided in the.

The forced circulation evaporator may be further provided in a region where a concentrated water outlet of the lower part of the chamber is provided, and a vortex offset member for canceling a vortex generated in the concentrated water. It is preferable that at least two or more plate-shaped members intersect.

According to the present invention, the wastewater discharged from the desulfurization tower has an effect that can be purified to meet the discharge water quality standards.

In addition, it is also possible to reduce the CAPEX and OPEX by reasonably determining the amount of wastewater treatment through the flow control unit.

However, the effects of the present invention are not limited to the above-mentioned effects, and other effects not mentioned will be clearly understood by those skilled in the art from the following description.

1 is a view schematically showing a wastewater treatment apparatus according to an embodiment of the present invention.
2 is a view schematically showing a mixing tank according to an example.
3 is a top view of FIG. 2.
4 is a view schematically showing a falling film evaporator according to an example.
5 is a view schematically showing a forced circulation evaporator according to an example.
6 is a view schematically showing a forced circulation evaporator according to an example.
7 is a view schematically showing a vortex offset member according to an example.

Hereinafter, the present invention will be described in detail with reference to embodiments and drawings of the present invention. These examples are only presented by way of example only to more specifically describe the present invention, it will be apparent to those skilled in the art that the scope of the present invention is not limited by these examples. .

Also, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs, and in the case of conflict, the specification including definitions The description of will prevail.

In the drawings, parts irrelevant to the description are omitted to clearly describe the proposed invention, and like reference numerals designate like parts throughout the specification. In addition, when a part "contains" a certain component, this means that the component may further include other components, without excluding other components, unless specifically stated otherwise. In addition, the "unit" described in the specification means one unit or block that performs a specific function.

In each step, an identification code (first, second, etc.) is used for convenience of description, and the identification code does not describe the order of each step, and each step does not explicitly describe a specific order in the context. It may be carried out in a different order than described above. That is, each step may be performed in the same order as specified, may be performed substantially simultaneously, or may be performed in the reverse order.

1 is a view schematically showing a wastewater treatment apparatus 1000 according to an embodiment of the present invention. Referring to Figure 1, the wastewater treatment apparatus 1000 according to an embodiment of the present invention SS for removing insoluble solids (suspended solids, SS) suspended in the treated water (wastewater) discharged from the desulfurization tower Removal unit 100; A COD removal unit 200 disposed at the rear end of the SS removal unit 100 to remove chemical oxygen demand (COD) of the water to be treated; A fluorine and heavy metal removal unit 300 disposed at a rear end of the COD removal unit 200 to remove fluorine and heavy metals contained in the water to be treated with COD removed; A calcium removal unit 400 disposed at a rear end of the fluorine and heavy metal removal unit 300 to remove calcium contained in the water to be treated; A nitrogen removal unit 500 disposed at a rear end of the calcium removal unit 400 to convert nitrogen contained in the water to be treated into a salt form to separate and remove the nitrogen; And disposed between the calcium removal unit 400 and the nitrogen removal unit 500, by measuring the degree of contamination of the water to be treated to determine the flow rate of the water to be discharged and the water to be treated to the nitrogen removal unit 500. It includes; a flow control unit 600. The present invention is to purify and discharge the waste water discharged from the desulfurization tower in accordance with the discharge water quality standards, it is possible to efficiently reduce the CAPEX and OPEX through the flow control unit 600.

SS removal unit 100 is to remove the insoluble solids (floating matter, SS) contained in the treated water (waste water) discharged from the desulfurization tower, it is possible to remove the insoluble solids by gravity settling method. In this case, a polymer flocculant may be used to increase the settling speed to improve the removal efficiency. The polymer coagulant is not particularly limited, but the use of an anionic polymer coagulant is advantageous for the removal efficiency.

The COD removal unit 200 may be disposed at the rear end of the SS removal unit 100 to reduce (remove) the chemical oxygen demand amount COD of the water to be treated. The COD of the treated water discharged from the desulfurization tower is caused by the NS compound produced by the reaction of SO _x and NO _x , and can be reduced by decomposing it. COD can be removed using a known NaOCl oxidation method. In other words, NaOCl was added to decompose the NS compound, and the excess OCl ⁻ was removed using NaHSO ₃ .

The fluorine and heavy metal removal unit 300 may be disposed at a rear end of the COD removal unit 200 to remove heavy metals and fluorine components contained in the water to be treated. Heavy metal means manganese, iron and the like, and is precipitated using various known chelating agents (ion exchange resin) and then removed. In the case of fluorine, it is removed by coprecipitation using aluminum as shown in the following formula (1).

[Formula 1]

^{Al 3 + + 3OH - + F} - → Al (OH) 3 · F ↓

The calcium removing unit 400 may be disposed at the rear of the fluorine and heavy metal removing unit 300 to remove calcium components contained in the water to be treated. Calcium components need to be removed since there is a high possibility of scale formation in piping and the like. Calcium can be removed by various methods, for example, can be removed by precipitation using Na ₂ CO ₃ , as shown in the following formula (2).

[Formula 2]

Ca ^{2 +} + Na ₂ CO ₃ → CaCO ₃ ↓ + 2Na ⁺

When the calcium component is removed using Na ₂ CO ₃ , a reaction formula such as the following Chemical Formula 3 and Chemical Formula 4 may proceed to side reaction, and may have an effect of removing the micro fluorine component from the water to be treated.

[Formula 3]

_{^{Ca 2 + + CO 3 2- +}} F - → CaCO 3 · F ↓

[Formula 4]

^{Ca 2 + + 2F - → CaF} 2 ↓

The nitrogen removal unit 500 may be disposed at the rear end of the calcium removal unit 400 to convert and remove the nitrogen component contained in the water to be treated in the form of a salt. As the water discharge standard is strengthened, the conventional technique has a limitation in removing nitrogen components, and thus the present invention can remove nitrogen components using two different evaporators, which will be described in more detail later.

The flow rate control unit 600 is disposed between the calcium removal unit 400 and the nitrogen removal unit 500 to measure the degree of contamination of the water to be treated, and then transfer the treated water to be discharged and the nitrogen removal unit 500. Determine the flow rate of the water to be treated. In order to reduce CAPEX and OPEX, it is important to see how effectively the facility can be operated. The water to be treated can be reduced to 1/30 of the initial nitrogen concentration by the nitrogen removal unit 500 to be described in detail later. In this case, the operation amount of the nitrogen removal unit 500 may increase, thereby increasing the burden. Accordingly, the flow control unit 600 determines the flow rate to be transferred to the nitrogen removal unit 500 so as to satisfy the water discharge standard after determining the state of the water to be treated before supplying the water to the nitrogen removal unit 500. do.

At this time, the wastewater treatment apparatus 1000 is connected to the flow control unit 600, the treated water determined to be discharged by the flow control unit 600 and the treated water from which nitrogen is removed by the nitrogen removal unit 500. A mixing tank 700 capable of receiving and mixing may be included. Specifically, the mixing tank 700 is one end is connected to the flow control unit 600 to accommodate the water to be determined that is not transferred to the nitrogen removal unit 500, the other end is connected to the nitrogen removal unit 500 After receiving the water to be passed through the nitrogen removal unit 500, these are mixed. After mixing, discharge is performed if it meets the discharge water quality standards. However, if the discharge water quality standards are not appropriate, the treated water may be purified again through a conveying pipe (not shown) connected to the nitrogen removing unit 500.

2 is a diagram schematically illustrating a mixing tank 700 according to an example, and FIG. 3 is a top view of FIG. 2. 2 and 3, the mixing tank 700 will be described in more detail. In the mixing tank 700, a cylindrical upper end 710 and a conical lower end 720 are combined to improve mixing efficiency. In the center of the lower portion 720, the discharge water discharge port for discharging the water can be formed. The upper end 710 of the mixing tank 700 may include a first inlet 711 through which the water to be treated determined to be discharged by the flow controller 600 flows; And a second inlet 712 through which the treated water from which nitrogen has been removed by the nitrogen removing unit 500 is introduced. At this time, the first inlet 711 and the second inlet 712 through the first inlet 711 and the second inlet 712 the water to be transferred into the mixing tank 700, the inner surface of the mixing tank 700 It may be provided in a tangential direction at one point on the side of the mixing tank 700 to form a swirl flow along the. The first inlet 711 and the second inlet 712 is preferably formed at the same height, it is preferable that the inflow of the water to be introduced does not collide with each other, it is disposed so that it can rotate in the same direction.

In addition, if necessary, the mixing tank 700 may be provided with a stirrer therein so that the incoming water can be mixed well.

Specifically, the nitrogen removal unit 500 described above will be described in detail. The nitrogen removal unit 500 includes: a falling film evaporator 510 in which concentrated water is formed by evaporating and condensing water by heat exchange with hot steam; And a forced circulation evaporator 550 which receives the concentrated water formed by the falling film evaporator 510 and removes nitrogen by crystallizing the nitrogen in the concentrated water in the form of a salt. The condensed water that is condensed after conversion to steam in the falling film evaporator 510 and the forced circulation evaporator 550 is transferred to the mixing tank 700, and the sludge containing nitrogen in the form of a salt is treated separately. In addition, in this process, contaminants not removed at the front end such as COD, SS and heavy metals may be removed together.

FIG. 4 is a view schematically illustrating a falling film evaporator 510 according to an example, and a vertical tube falling film (VTFF) evaporator 510 will be described in detail with reference to FIG. 4. In front of the falling film evaporator 510, a heating device (not shown) capable of heating the water to be treated may be configured. The heating device may be installed inside the falling film evaporator 510, in which case it may have the advantage of reducing heat exchange efficiency and pressure loss. Falling film evaporator 510 is a plate-shaped flow uniform device 512 is horizontally installed on the upper housing 511 and the treated water inlet 513 is installed higher than the flow uniform device 512, The water to be treated may be configured to be supplied to the upstream space S1 above the flow uniform device 512. A plurality of evaporation tubes 514 are densely installed inside the housing 511, and the upper end of the evaporation tube 514 is installed through the flow uniformity device 512. The upstream space S1 and the evaporation tube ( Internal spaces of the 514 are installed to communicate with each other. As a result, the water to be supplied to the upstream space S1 flows down the inner wall of the evaporation tube 514. The water to be treated which flows downward through the inner wall of the evaporation tube 514 and forms a falling film is heated by heat exchange with the water vapor introduced into the heat exchange space S2 in the middle of the housing 511 and the wall of the evaporation tube 514 interposed therebetween. As the water contained in the water to be treated evaporates. The falling film evaporator 510 can suppress the boiling point without pressure loss in the device, and even if the temperature difference with the heating fluid is small, the heat transfer rate is very high, so that it is possible to minimize the contact time with a heating element such as water vapor, and the like. The temperature gradient in the liquid dura, which is maintained at about 2 mm, is very small, which minimizes the temperature rise of heat-sensitive liquids. The concentrated water concentrated by the falling film evaporator 510 is transferred to the forced circulation evaporator 550 at a later stage, and the purified condensed water is transferred to the mixing tank.

FIG. 5 is a view schematically illustrating a forced circulation evaporator 550 according to an example, and will be described in detail with reference to FIG. 5 for a forced circulation type (FC) evaporator. Forced circulation evaporator 550 is a cyclone type device, the concentrated water introduced into the evaporation under reduced pressure to discharge the steam generated through the steam outlet 554 of the upper portion and concentrated water through the concentrated water outlet 557 of the lower portion A chamber 551 provided with an inner space to be discharged; A concentrated water inlet 552 connected to a side surface of the chamber 551 in a tangential direction of the inner circumferential surface of the chamber 551 so as to rotate in a swirling flow along the inner circumferential surface of the chamber 551; And a region provided between the concentrated water inlet 552 and the steam outlet 554 of the inner space of the chamber 551 and protruding from the inner wall of the chamber 551 to prevent the rising of the mist contained in the generated steam. At least one partition 553 for; may include. Through this, the concentrated water transported from the falling film evaporator 510 is rotated in the form of a vortex in the chamber 551 and decompression evaporation occurs at the surface of the vortex, and the evaporation efficiency is increased due to the increase in turbulence intensity and flashing area. The lower the hydrostatic pressure toward the center of the vortex, the lower the submersible loss, and the mixing effect of the vortex vortex forms round and even crystals to improve the removal efficiency of the solid material. There is no stagnation of fluid inside, preventing caking.

At least one barrier wall 553 may be provided in the chamber 551 to prevent a rising of a mist contained in the generated steam. In the process of generating and rising steam, large and small droplets (mist, droplets) are raised together, the relatively large droplets are blocked by the partition 553 is lowered to the bottom by gravity.

The partition 553 may be provided in a region between the concentrated water inlet 552 and the steam outlet 554 in the space inside the chamber 551 and may protrude from the inner wall of the chamber 551. Preferably, the chamber 551 may protrude to be inclined upwardly at an angle of 90 to 180 degrees from the inner wall of the chamber 551 to more effectively induce the blocking of the drop and the falling of the blocked drop.

In addition, a built-in demister 555 may be further provided in case a relatively small droplet rises without being blocked by the partition 553. The built-in demister 555 is provided in at least one region of the upper and lower portions of the partition 553 in the chamber 551, and a mesh for blocking the droplets contained in the steam in the process of upwardly discharging the generated steam. Type plate member 561. As a result, droplets that are not removed through the partition 553 may be effectively filtered during the vapor raising process.

In addition, instead of the built-in demister 555 as shown in Figure 6 may be provided with an external demister 556 demister. External demister 556 is a device provided separately to the outside of the chamber 551 is a chevron (chevron) for blocking the droplet contained in the steam is provided so that the discharged steam is connected to the end of the steam outlet 554 The type member may be provided on the movement path of the steam flowing therein. When the demister is configured as an external demister 556 type outside the chamber 551, the volume of the chamber 551 using relatively high quality and expensive materials can be reduced, which is economical and minimizes contamination of the demister. There is an advantage in that it can be easy to maintenance, such as cleaning.

In addition, the chamber 551 of the forced circulation evaporator is preferably formed in the form of the inner wall of the chamber 551 is inclined downward to reduce the radius of rotation of the concentrated water toward the concentrated water outlet 557 of the lower portion. At this time, a rapid vortex occurs in the concentrated water outlet 557 according to the lower structure of which the area of the cross section is gradually narrowed. As a result, a cavitation is formed, which adversely affects the pump that discharges the concentrated water in the subsequent process. Get mad. In order to solve this problem is provided in the region where the concentrated water outlet 557 of the lower portion of the chamber 551 is provided, the vortex offset member 560 for offsetting the vortex generated in the concentrated water; You may. The vortex canceling member 560 may be formed in a form in which at least two or more plate members 561 are crossed as shown in FIG.

Next, a wastewater treatment method for treating wastewater discharged from a desulfurization tower will be described. In the description, the description thereof will be omitted in the overlapping portion described above.

Wastewater treatment method according to an embodiment of the present invention, SS removal step of removing insoluble solids (suspended solids, SS) suspended in the water to be discharged from the desulfurization tower; After the SS removing step, removing the chemical oxygen demand (COD) of the water to be treated; After the COD removal step, a fluorine and heavy metal removal step of removing fluorine and heavy metals contained in the COD-removed treated water; After the fluorine and heavy metal removal step, removing calcium contained in the water to be treated; After the calcium removal step, nitrogen removal step of separating and removing the nitrogen contained in the water to be treated in the form of a salt; And a flow rate control step of determining a flow rate of the treated water to be discharged and the treated water to be transferred to the nitrogen removing step by measuring the degree of contamination of the treated water between the calcium removing step and the nitrogen removing step. In order to purify and discharge the wastewater discharged from the desulfurization tower in accordance with the discharge water quality standards, the present invention may perform a flow rate control step, thereby effectively reducing CAPEX and OPEX.

Hereinafter, the configuration and effects of the present invention will be described in more detail with reference to specific examples. However, this embodiment is intended to illustrate the present invention in more detail, and the scope of the present invention is not limited to these examples.

EXAMPLE

As shown in FIG. 1, a wastewater treatment apparatus including a flow control unit and a mixing tank was configured.

Experimental Example

Wastewater (treated water) discharged from the desulfurization tower was treated using the above example. At this time, 85% of the water to be treated is transferred to the nitrogen removing unit, and 15% of the water is transferred to the mixing tank according to the judgment of the flow control unit. The state was measured. The results are shown in Table 1 below.

Classification [mg / L] A B C D COD 250 150 6 30 SS 10,000 180 0 30 Mn 270 12 0 2 F 100 18 0 3 T-N 150 165 5 30

As shown in Table 1, it was found that by effectively treating the treated water through the flow control unit, the treated water can be purified to meet the discharge water quality standards while reducing CAPEX and OPEX.

In the present specification, only a few examples of various embodiments performed by the present inventors are described, but the technical idea of the present invention is not limited thereto, but may be variously modified and implemented by those skilled in the art.

1000: wastewater treatment device 100: SS removal unit
200: COD removal unit 300: fluorine and heavy metal removal unit
400: calcium removal unit 500: nitrogen removal unit
510: falling film evaporator 511: housing
512: uniform flow device 513: inlet to be treated water
514: evaporation tube 515: concentrated water outlet
516: condensate outlet 550: forced circulation evaporator
551: chamber 552: concentrated water inlet
553 bulkhead 554 steam outlet
555: internal demister 556: external demister
557: concentrated water outlet 560: vortex offset member
561: plate member 600: flow control unit
700: mixing tank 710: top
720: bottom 711: first inlet
712: second inlet S1: upstream space
S2: heat exchange space S3: liquid low

Claims (12)

SS removal step of removing insoluble solids (suspended solids, SS) suspended in the treated water discharged from the desulfurization tower;
After the SS removing step, removing the chemical oxygen demand (COD) of the water to be treated;
After the COD removal step, a fluorine and heavy metal removal step of removing fluorine and heavy metals contained in the COD-removed treated water;
After the fluorine and heavy metal removal step, removing calcium contained in the water to be treated;
After the calcium removal step, nitrogen removal step of separating and removing the nitrogen contained in the water to be treated in the form of a salt;
A flow rate control step of determining a flow rate of the treated water to be discharged and the treated water to be transferred to the nitrogen removing step between the calcium removing step and the nitrogen removing step, by measuring the degree of contamination of the treated water; And
And mixing the treated water discharged and determined in the flow rate control step with the nitrogen-removed treated water to be mixed.
The nitrogen removal step is performed in sequence by falling film evaporator and forced circulation evaporator,
The forced circulation evaporator may include: a chamber provided with an internal space such that the concentrated water introduced into the chamber is evaporated under reduced pressure so that steam generated through the upper steam outlet is discharged and the concentrated water is discharged through the lower concentrated water outlet; A concentrated water inlet for injecting concentrated water connected to a side of the chamber in a tangential direction of the inner circumferential surface of the chamber so that the concentrated water rotates in a swirling direction along the inner circumferential surface of the chamber; And at least one partition wall provided in a region between the concentrated water inlet and the vapor outlet of the chamber internal space and protruding from the inner wall of the chamber to prevent a rising of the mist contained in the generated steam.
In the mixing step, the discharged treated water and the treated water from which nitrogen has been removed by the nitrogen removing unit are introduced and mixed through different inlets, respectively. delete delete The method of claim 1,
The wastewater treatment method characterized by the discharged-determined treated water and the to-be-processed water by which nitrogen was removed by the nitrogen removal part are mixed, forming a swirl flow. The method of claim 1,
The mixing step, characterized in that the waste water treatment method. The method of claim 1,
The falling film evaporator is provided with a plurality of evaporation tube therein,
The waste water treatment method characterized in that the water to be introduced is evaporated by heat exchange with the hot steam supplied to the outer wall side of the evaporation tube while flowing down the inner wall of the evaporation tube to form a falling film. The method of claim 1,
The forced circulation evaporator is provided in at least one of the upper and lower regions of the partition wall in the chamber,
And a built-in demister, which is a mesh type plate-shaped member for blocking the droplets contained in the steam in the process of upwardly discharging the generated steam. The method of claim 1,
The forced circulation evaporator is provided so that the discharged steam is connected to the end of the steam outlet to the outside of the chamber,
And an external type demister provided on a moving path of the steam into which a chevron type member for blocking droplets contained in the steam is introduced. The method of claim 1,
The forced circulation evaporator,
And a vortex offset member provided in a region provided with a concentrated water outlet at a lower portion of the chamber to offset vortex generated in the concentrated water. The method of claim 9,
The vortex offset member is characterized in that at least two or more plate-like member is crossed, wastewater treatment method. The method of claim 1,
A front end of the falling film evaporator is provided with a heating device capable of heating the water to be treated, wastewater treatment method. The method of claim 1,
The wastewater treatment method, characterized in that the inside of the falling film evaporator is provided with a heating device for heating the water to be treated.

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