KR102339425B1 - Electrode plate for wastewater treatment and Nitrogen-based wastewater treatment system using the same, and Operation method thereof - Google Patents

Abstract

The present invention relates to an electrode plate for wastewater treatment, a nitrogen-based wastewater treatment system using the same, and a method for operating the same, and more specifically, to an electrode plate, a wastewater treatment system using the same, and a method for operating the same, wherein the electrode plate uses an electrolysis device to remove nitrogen-based components from wastewater containing a large amount of nitrogen-based components such as ammonia nitrogen, nitrate nitrogen or nitrite nitrogen and can provide best nitrogen decomposition efficiency by controlling the coating ratio of two metal elements coated on the electrode plate of the electrolysis device.

Description

Electrode plate for wastewater treatment, nitrogen-based wastewater treatment system using same, and operation method thereof

The present invention relates to an electrode plate for wastewater treatment, a nitrogen-based wastewater treatment system using the same, and an operating method thereof, and more particularly, from wastewater containing a large amount of nitrogen-based components such as ammonia nitrogen, nitrate nitrogen or nitrite nitrogen. An electrode plate capable of providing the best nitrogen decomposition efficiency by controlling the coating ratio of two types of metal elements coated on the electrode plate of the electrolysis device by using an electrolysis device to remove nitrogen-based components, and a wastewater treatment system using the same; It's about driving.

In the process of manufacturing semiconductors, there is a process of washing using nitrogen trifluoride and ammonia gas in the etching process, and the generated wastewater contains nitrogen trifluoride and ammonia mixed with ammonia nitrogen and hydrofluoric acid in high concentrations.

The mixed wastewater containing hydrofluoric acid used in the etching process is transferred to a separate treatment company and then undergoes a wastewater treatment process. Since the ion concentration of fluorine is usually 10,000 to 25,000 ppm or more, the concentration of fluorine component is first determined After performing the lowering process, the ammonia nitrogen removal process is performed or the ammonia nitrogen concentration is lowered and then the fluorine component is removed.

In general, it is a physicochemical method that neutralizes mixed wastewater containing other harmful substances such as hydrofluoric acid with slaked lime, etc. and repeats the process of filtering sludge several times. Secondary and tertiary treatments such as biochemical treatment or electrolysis treatment are being carried out to remove them.

However, the biological treatment method is suitable for wastewater treatment with a lot of organic matter and is widely used for sewage treatment, but it requires a large site, requires a lot of construction cost, and has the disadvantages of generating a large amount of sludge, so it is preferable to proceed with the electrolysis treatment method do.

Therefore, although the electrolysis treatment method is suitable to remove ammonia nitrogen contained in the mixed wastewater of the semiconductor industry, a system capable of efficiently decomposing and removing the high concentration ammonia nitrogen component is required.

Korean Patent No. 10-1112560 (registration on Jan. 30, 2012; hereinafter referred to as 'Prior Document 1') proposes an organic sludge reduction device with a low energy consumption type two-stage electrolysis method using an electrolytic device having a multi-layer matrix structure electrode. did In Prior Document 1, treated water obtained by separating sludge from a settling tank from wastewater containing a large amount of organic matter is introduced into the electrolytic cell to destroy the organic cell membrane contained in the treated water to increase the sludge removal rate. In addition, the electrode of the electrolytic cell coated with various metal elements has been described, but only those used for the purpose of destroying cell membranes of organic substances are described.

Korean Patent Application Laid-Open No. 10-2021-0003026 (published on 11/11/2021; hereinafter referred to as 'Prior Document 2') proposes a gray water system for wastewater containing colored substances. The prior document 2 is to sterilize heavy water, which is an intermediate step between waterworks and sewage, and to oxidize and remove ammonia nitrogen contained therein.

As described above, the conventional electrolytic device uses iridium or platinum coated as an electrode, but it is suitable only for decomposing organic matter or decomposing and removing low concentration ammonia nitrogen. It was not suitable for wastewater treatment in terms of treatment efficiency.

Accordingly, there is a need for an electrode plate and a system capable of increasing the efficiency so that wastewater containing high concentration ammonia nitrogen discharged from a high semiconductor manufacturing plant can be treated by electrolysis.

Korean Patent Registration No. 10-1112560 (Registered on January 30, 2012): Low energy consumption type two-stage electrolytic organic sludge reduction device using an electrolytic device with electrodes of a multi-layer matrix structure Korean Patent Laid-Open Patent No. 10-2021-0003026 (published on 11/11/2021): Gray water system for wastewater containing colored substances

Accordingly, the electrode plate for wastewater treatment of the present invention, a nitrogen-based wastewater treatment system using the same, and a method for operating the same,

An object of the present invention is to provide an electrode plate that enables efficient decomposition and removal of nitrogen-based components by changing the coating ratio of the electrode plate of the electrolysis device to be optimized for high-concentration nitrogen-based wastewater treatment, a system using the same, and an operating method thereof.

The electrode plate for wastewater treatment of the present invention for achieving the above object, a nitrogen-based wastewater treatment system using the same, and a method for operating the same,

In the electrode plate for wastewater treatment that electrolyzes and removes wastewater containing a large amount of nitrogen-based components, it is made by complex coating on a titanium substrate with a (iridium: platinum) ratio of (60:40) to (80:20). .

Preferably, the coating ratio of iridium and platinum on the titanium substrate is 68:32.

In addition, there is provided a wastewater treatment system for electrolyzing and removing wastewater containing a large amount of nitrogen-based components, the wastewater treatment system comprising: a water collecting tank for introducing and storing wastewater containing a large amount of nitrogen-based components; a pretreatment tank for mixing and stirring an oxidation promoter with the wastewater introduced from the water collecting tank to adjust the conductivity to promote the electrolysis reaction of the wastewater; an oxidation promoter storage tank for storing the oxidation promoter supplied to the pretreatment tank; a retention tank that receives and temporarily stores wastewater whose conductivity is controlled from the pretreatment tank, and is equipped with a conductivity sensor; A wastewater electrolysis supply pipe receiving wastewater with controlled conductivity from the retention tank, and a wastewater electrolysis supply pipe introducing wastewater through the wastewater electrolysis supply pipe to electrolyze and remove nitrogen-based components by a plurality of built-in electrode plates, but the electrode plate is on a titanium substrate An electrolysis device comprising: an electrolyzer formed by complex coating with a (iridium:platinum) ratio of (60:40) to (80:20); and a control unit that controls valves of pipes connecting each device or receives various sensor values to control each device.

The electrolyzer of the electrolysis device has a plate-shaped decomposition reaction chamber formed in the vertical direction, an inlet through which wastewater is introduced is formed on the lower rear surface, and an outlet port for discharging the electrolyzed wastewater is formed on the upper rear surface. And a plate-shaped electrolytic body arranged as; A plurality of electrode plates installed in the decomposition reaction chamber inside the electrolyte body in a space between the lower inlet and the upper outlet in multi-layered front and rear directions, spaced apart from each other, and connected so that the anode and the cathode cross each other; it is composed of.

The electrolysis apparatus may be configured to increase the decomposition treatment rate of nitrogen-based components by electrolysis or increase the throughput by connecting a plurality of electrolyzers in series or in parallel or in series and in parallel.

The operating method of the nitrogen-based wastewater treatment system of the present invention comprises: a wastewater storage step of storing wastewater containing a large amount of nitrogen-based components in a water collecting tank; an oxidation promoter mixing step of supplying wastewater from the water collection tank to the pretreatment tank, and further adding an oxidation promoter in the oxidation promoter storage tank and stirring; The wastewater mixed with the oxidation promoter in the pretreatment tank is transferred to the retention tank, and if the conductivity measured by the conductivity measuring sensor of the retention tank is low compared to the conductivity set in the control unit, more oxidation promoter is added. Conductivity matching and equalization step of adding more to match the conductivity, and temporarily storing it before input to the process to be described later to equalize the conductivity; Nitrogen-based component electrolysis step in which wastewater from the retention tank is introduced into the lower part of the electrolytic cell in which the electrode plates, which are vertical plates, are arranged in multiple rows, passes between the electrode plates and moves to the upper part, where an electrolysis reaction occurs, decomposing and discharging nitrogen-based components in the wastewater including ;.

In the nitrogen-based component electrolysis step, a plurality of electrolyzers are connected in series to increase the treatment rate of nitrogen-based wastewater; or a wastewater dispersion treatment step of increasing the amount of nitrogen-based wastewater treated by connecting a plurality of electrolyzers in parallel; Either or both can be made.

Here, in the oxidation promoter mixing step, the stirring time is set to 10 to 30 minutes; In the conductivity matching and homogenization step, the conductivity of the wastewater is formed at 4 to 8 (S/m), and is homogenized by staying for 30 to 60 minutes; In the nitrogen-based component electrolysis step, the electrolysis may be performed by moving the wastewater to have a residence time of 1 to 5 minutes per one electrolyzer.

The electrode plate for wastewater treatment of the present invention according to the above solution, a nitrogen-based wastewater treatment system using the same, and an operating method thereof,

By coating the electrode plate with a coating ratio of iridium to platinum on a titanium substrate in a ratio of 60:40 to 80:20, the efficiency of wastewater treatment by increasing the decomposition and removal rate of nitrogen-based components in high-concentration nitrogen-based wastewater generated in semiconductor manufacturing plants It has become possible to provide a system including an improved electrolysis device and a method for operating the same.

1A and 1B are schematic views showing a nitrogen-based wastewater treatment system according to a preferred embodiment of the present invention.
2A to 2C are a perspective view and a cross-sectional view schematically illustrating an electrolytic cell according to an embodiment of the present invention.
3A to 3C are schematic views showing an example of an electrolytic cell arrangement of an electrolysis device according to an embodiment of the present invention.
4 is a process diagram illustrating a method of operating a nitrogen-based wastewater treatment system according to the present invention.

Since the present invention can have various changes and can have various embodiments, specific embodiments are illustrated in the drawings and described in the detailed description. However, this is not intended to limit the present invention to specific embodiments, and it should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

When an element is referred to as being “connected” or “in communication with” another element, it should be understood that the element may be directly connected to the other element, but another element may exist in between. On the other hand, when it is mentioned that a certain element is "directly connected" or "directly connected to" another element, it should be understood that the other element does not exist in the middle.

The terms used in the present application are only used to describe specific embodiments, and are not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly dictates otherwise. In the present application, terms such as “comprise” or “have” are intended to designate that a feature, number, step, operation, component, part, or combination thereof described in the specification exists, but one or more other features It should be understood that this does not preclude the existence or addition of numbers, steps, operations, components, parts, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in a commonly used dictionary should be interpreted as having a meaning consistent with the meaning in the context of the related art, and should not be interpreted in an ideal or excessively formal meaning unless explicitly defined in the present application. does not

Hereinafter, the present invention will be described in more detail.

According to the electrode plate according to the present invention, the total nitrogen (TN) of wastewater containing a nitrogen-based component including a semiconductor manufacturing process in a high concentration is lowered by an electrolysis reaction. In particular, it provides a coating structure that can efficiently decompose ammonia nitrogen (NH ₃ -N), nitrate nitrogen (NO ₃ -N), nitrite nitrogen (NO _{2 -N), and the like.}

Electrolysis of the electrode plate of the present invention is made by disposing a plurality of electrode plates close to each other in a monopolar shape and connecting different poles in a zigzag form to allow wastewater to pass between the electrode plates.

Typically, it is installed vertically to have an electrolytic cell in which the decomposition reaction chamber is formed vertically in the form of a plate, and a plurality of electrode plates are placed in the inner decomposition reaction chamber at regular intervals in the front and rear directions, and each electrode plate has both sides. Electrolysis is made between the front and rear plates by connecting different poles in a zigzag through the

The electrode plate may be provided in various forms such as a wide plate body, a mesh form having a plurality of through holes therein, or a perforated form.

The electrode plate is made of a titanium plate as a basic base, and the outer surface is coated with iridium and platinum.

The coating ratio of iridium and platinum is preferably used for electrolysis by coating in the range of 60:40 to 80:20, coating with 60 wt% or less of iridium and coating with 40 wt% or more of platinum, and iridium 80 When the amount of coating is more than 20% by weight and the amount of platinum is less than 20% by weight, the treatment efficiency of total nitrogen is lowered, so it is preferable to use the coating within the above range.

Also, more preferably, iridium and platinum are coated in a ratio of 68:32 to increase nitrogen treatment efficiency under the same conditions.

In addition, the electrode plate may be coated with iridium and platinum by using stainless steel as a substrate other than a titanium plate, and may be coated by various known methods.

An electrode plate in which iridium and platinum are coated on a titanium plate in the above ratio can be applied and used in a wastewater treatment system.

As shown in FIG. 1A , the nitrogen-based wastewater treatment system 10 according to the present invention includes a water collecting tank 20 for introducing and storing wastewater. The water collecting tank 20 directly stores wastewater containing a large amount of nitrogen-based components discharged from the industrial complex, or stores wastewater supplied to remove nitrogen-based components after performing another wastewater treatment process.

The wastewater stored in the water collecting tank is supplied to the pretreatment tank 30 .

The pretreatment tank 30 is a tank for controlling the conductivity of wastewater by mixing an oxidation promoter to promote an electrolysis reaction for wastewater. The set conductivity is a conductivity at which the electrolysis of the nitrogen-based component can be easily achieved.

This reference conductivity can be preset through the control unit 70, and the conductivity can be varied according to the electrolysis target. Therefore, in the present invention, it can be formulated to have a set conductivity by controlling the supply amount of the oxidation promoter supplied to the pretreatment tank and the wastewater of the water collecting tank.

In addition, a stirrer is installed in the pretreatment tank 30 to uniformly stir the oxidation promoter by stirring. At this time, the pretreatment tank 30 has an inlet 31 through which the oxidation promoter and wastewater from the collection tank are introduced by the partition wall 33 with an open lower part, and the oxidation promoter and the wastewater are moved through the lower part of the partition wall and stirred. It is composed of a stirring unit 32, and a fluid flow is generated in such a way that the upper wastewater of the stirring unit 32 is transferred to the next treatment tank, thereby preventing the inflowing wastewater from being sufficiently stirred with the oxidation accelerator and discharged to the next treatment tank. have. A stirring device is installed in the stirring unit 32 partitioned inside the pretreatment tank, and the introduced wastewater and the oxidation promoter are stirred as uniformly as possible. One or more stirring devices may be installed in the pretreatment tank to achieve uniform mixing.

Here, the oxidation promoter supplied to the pretreatment tank 30 is supplied through the oxidation promoter storage tank 40 .

The oxidation promoter storage tank 40 is a mixture of NaCl and industrial water, and has a uniform concentration by means of a stirrer. The oxidation promoter of the oxidation promoter storage tank is supplied to the pretreatment tank by a pump so that the operation of the pump is controlled by the control unit.

Next, the retention tank 50 introduces wastewater mixed with the oxidation promoter from the pretreatment tank 30, temporarily stores it, and uniformizes it.

The retention tank 50 is configured to be separated from the pretreatment tank 30 as shown in FIG. 1A so that wastewater after stirring in the pretreatment tank is completed can be supplied to the retention tank through a pipe, and as shown in FIG. 1B , the retention tank 50 It is integrally configured with (30) so that the stirred wastewater from the pretreatment tank overflows and is supplied to the retention tank.

The retention tank 50 may additionally be equipped with a conductivity measuring sensor to measure the conductivity of the contained wastewater, and transmit the measured value to the control unit to control the conductivity of the wastewater through the control unit.

In addition, the pretreatment tank 30 and the retention tank 50 may additionally install a cover and an exhaust line 51 to discharge the generated gas to the outside. In the exhaust line 51, a fan is mounted on the line to facilitate gas inflow into the pretreatment tank and/or the retention tank, and a shut-off valve can be installed to control the opening and closing of the exhaust line by the control unit, It is possible to purify the exhaust gas by installing a filter device at or at the end of the line, or by installing a separate follow-up process.

The wastewater of the retention tank 50 whose conductivity is controlled is supplied to the electrolysis device 60 to decompose and remove nitrogen-based components by electrolysis.

As shown in Figs. 2a to 2c, the electrolysis device 60 includes a wastewater electrolysis supply pipe 61 receiving the wastewater from the retention tank 50, and an electrolyzing tank 62 for electrolyzing the supplied wastewater; , is composed of a wastewater electrolysis discharge pipe 63 for discharging the electrolysis-completed wastewater.

The electrolytic cell 62 has a tank similar to the monopolar electrolyzer mentioned in Korean Registration No. 10-1031906, and a decomposition reaction chamber 641 having a plate-shaped space in the vertical direction is formed therein, and the decomposition reaction chamber An inlet 642 through which the wastewater electrolysis supply pipe 61 is communicated is formed on the rear side of the lower side of the electrolysis body, and an outlet 643 through which the wastewater electrolysis discharge pipe 63 is communicated is formed on the rear side of the upper side of the decomposition reaction chamber ( 64) is provided. The electrolytic body 64 is formed of a transparent material so that the internal state can be checked, so that replacement of parts can be easily identified from the outside and rapid replacement can be made. Typically, transparent plastic containing acrylic will be used can

The electrolytic body 64 is composed of a front plate and a rear plate, and is coupled to be watertight by fastening a plurality of bolts, and the front plate has an inner side protruding forward to form an electrolysis chamber therein, and the rear plate is an inlet port A wastewater electrolysis supply pipe and a wastewater electrolysis discharge pipe having a discharge port are installed in communication with each other.

In the decomposition reaction chamber 641 inside the electrolysis body 64, a plurality of electrode plates 65 are disposed between the inlet 642 and the outlet 643, spaced apart from each other by a predetermined distance in the front-rear direction. A plurality of the electrode plates 65 are spaced apart in the front and rear directions at regular intervals, are arranged on both sides in a zigzag form, and the electrodes are connected through the protruding portions on both sides, so that the entire electrode plate is alternately arranged on both sides of the cathode. .

In the electrode plate 65 according to the present invention, iridium and platinum are mixed and coated on a titanium substrate to increase the electrolysis rate of nitrogen-based components, and as a coating ratio, iridium and platinum are used in a weight % ratio of 60:40 to 80:20. coating is provided.

In the electrolytic cell 62 having this structure, the wastewater of the retention tank flows in through the inlet at the bottom, and the inflow wastewater moves upward while passing between the plurality of electrode plates 65, and electrolysis occurs between the electrode plates during the movement process. The nitrogen-based components are decomposed, and the wastewater on which the nitrogen-based components have been decomposed is introduced into the wastewater electrolysis discharge pipe 63 through the upper outlet 643 and discharged to further perform a process to be described later.

Next, the control unit 70 controls the intermittent operation of various valves and device driving of each process. That is, the conductivity is set by increasing or decreasing the conductivity by receiving the measured value from the conductivity measuring sensor of the retention tank, comparing it with the previously set conductivity, and increasing the inflow of wastewater supplied to the pretreatment tank or increasing the inflow of the oxidizing agent into the tank according to the condition It can form wastewater with

In addition, the operation of the shut-off valve or fan installed in the exhaust line of the pretreatment tank and the retention tank may be intermittent, and the operation of the agitator of the pretreatment tank may be controlled.

In addition, as shown in Fig. 3a, the electrolysis device 60 according to the present invention connects a plurality of electrolytic cells 62 in series to increase the decomposition rate of the remaining nitrogen-based components while the wastewater of the retention tank sequentially passes through each electrolytic cell. can

In addition, as shown in Fig. 3b, the electrolysis device 60 of the present invention connects a plurality of electrolytic cells 62 in parallel to branch the wastewater of the retention tank to each electrolyzer, thereby increasing the amount of nitrogen-based components treated.

In addition, as shown in Fig. 3c, in the electrolysis device 60 of the present invention, the retention tank 50 and a plurality of electrolyzers 62 are connected in parallel, and a plurality of electrolyzers are connected in series to each electrolyzer connected to the retention tank, so that the simultaneous throughput It can be provided in a structure to increase the decomposition rate of nitrogen-based components while increasing the.

In addition, the electrolysis cell may be repeated several times by connecting the last electrolyzer and the first electrolyzer among the plurality of electrolyzers with a bypass pipe to circulate the wastewater to effect electrolysis.

A method of operating a nitrogen-based wastewater treatment system according to the present invention will be described with reference to FIG. 4 .

The operating method of the present invention performs a wastewater storage step first.

The wastewater storage step is a step of collecting and storing wastewater containing a large amount of nitrogen-based components in a water collecting tank. The water collecting tank may be a water collecting tank installed in a factory that discharges wastewater, or may be a water collecting tank of a treatment company transferred and collected from a plurality of wastewater discharge plants.

Next, the oxidation promoter mixing step is performed. The oxidation promoter mixing step is a step of controlling the conductivity by introducing the oxidation promoter stored in the oxidation promoter storage tank into the pretreatment tank in which the wastewater is stored. At this time, in the oxidation promoter mixing step, the wastewater collected in the pretreatment tank and the oxidation promoter are uniformly mixed by stirring.

At this time, it is preferable that the stirring time of the pretreatment tank is made to be 10 to 30 minutes, so that the stirring is sufficiently made to be uniform and then transferred to the retention tank. If the stirring time is provided within 10 minutes, uniformity is not sufficiently achieved, and if driven for more than 30 minutes, the degree of uniformity enhancement is insufficient, so it is preferable to form within the above range. In addition, it is preferable to delay the supply of wastewater from the water collecting tank by the stirring time interval rather than continuous supply and then proceed with the discontinuous supply method.

Conductivity matching and equalization steps are then performed.

The wastewater mixed with the oxidation promoter in the pretreatment tank is transferred to the retention tank, and the conductivity, which is a value measured by the conductivity measuring sensor of the retention tank, is transmitted to the control unit. If the measured conductivity is higher than the set conductivity, the amount of wastewater input from the water collecting tank to the pretreatment tank is increased to match the conductivity in the retention tank with the degree set in the control unit.

Since the present invention is to decompose and remove nitrogen components from wastewater containing nitrogen-based components, the conductivity can be formed to be 4 to 8 (S/m) so that the electrolysis of the nitrogen component can be easily performed. Here, the conductivity is the highest at 6 (S/m), and at 6 or more, the improvement of treatment efficiency is insufficient, and at 6 or less, the treatment efficiency is lowered, so it is preferable to maintain the conductivity at 6 (S/m).

In addition, the residence time in the residence tank can be sufficiently homogenized by allowing the residence to be made for 30 to 60 minutes. At 30 minutes or less, homogenization was not performed well, and in 60 minutes or more, the uniformity promotion rate was insufficient, so it is preferable to set the residence time in the above range.

Next, an electrolysis step is performed.

In the electrolysis step, the wastewater stored in the retention tank is introduced into the electrolyzer and passed between the electrode plates in the electrolyzer to undergo electrolysis to decompose and remove nitrogen-based components contained in a large amount in the wastewater.

In the electrolysis step, a plurality of electrolyzers are connected in series to increase the processing efficiency of nitrogen-based components; or a wastewater dispersion treatment step of increasing the amount of nitrogen-based wastewater treatment by connecting a plurality of electrolyzers in parallel; Either or both may be performed.

The electrolysis cell may be subjected to electrolysis by setting the passage and residence time of each electrolytic cell to 1 to 5 minutes. When wastewater is supplied at a rate of less than 1 minute, there is a problem in that the electrolysis efficiency of nitrogen-based components in the electrolyzer is lowered, and when wastewater is supplied at a rate of 5 minutes or more, the degree of improvement of the electrolysis rate in the electrolyzer is insufficient. It is desirable to allow the electrolysis to pass through the electrolyzer in time.

When NaCl is added as an oxidation promoter, the reaction in the electrolyzer occurs as follows.

NaCl + H ₂ O + 2e ^- → NaOCl + H ₂ ↑

NaOCl → Na ⁺ + OCl ^-

OCl ^- + H ₂ O ↔ HOCl + OH ^-

Direct oxidation of ammonia contained in wastewater is performed as follows, and nitrogen is discharged as a gas.

NH ₃ + 3OH ^- → 0.5N ₂ + 3H ₂ O + 3e ^-

In addition, the indirect oxidation of ammonia is performed as follows.

2NH ⁺ + 3HOCl → N ₂ + 3H ₂ O + 5H ⁺ + 3Cl ^-

2NH ₃ + 6Cl ^- → N ₂ + 6HCl + 6e ^-

In addition, the reaction of ammonia nitrogen is generated as follows.

NH4 ⁺ + HOCl → NH ₂ Cl + 5H ₂ O + H ⁺

NH ₂ Cl + HOCl → NHCl ₂ + H ₂ O

2NH ₂ Cl + HOCl → N ₂ ↑ + 3HCl + H ₂ O

NHCl ₂ + H ₂ O → NCl ₃ + H ₂ O

As described above, ammonia nitrogen releases nitrogen as a gas by direct or indirect oxidation reaction, and generates ozone and hydroxyl groups to perform sterilization in parallel.

Hereinafter, the performance was confirmed through the Examples of the present invention.

Example

Company A's HF wastewater was provided and treated by supplying it to the system of the present invention.

Only one electrolyzer of the electrolysis device was used to decompose nitrogen contained in wastewater.

[Experimental Example 1]

The treatment efficiency with respect to total nitrogen was measured by changing the coating ratio of the electrode plate installed in the electrolytic cell.

[Table 1] shows the total nitrogen (TN) concentration and conductivity of wastewater before the electrolysis reaction.

[Table 1]

Electrolysis was performed for 2 minutes after changing the coating ratio of iridium:platinum using titanium as a substrate for the electrode plate. The coating ratio was converted to 10% by weight and the change in TN concentration in the wastewater was measured and shown in [Table 2] below.

[Table 2]

As shown in [Table 2], in the wastewater subjected to the electrolysis reaction using an electrode plate coated with iridium and platinum in a ratio of (60:40) to (80:20), the treatment efficiency of TN concentration is 92% or more appear.

[Experimental Example 2]

Under the same conditions as in Experimental Example 1, the electrolysis reaction was performed for 2 minutes by subdividing the coating ratio of iridium and platinum of the electrode plate.

Changes in TN concentration in wastewater were measured and shown in [Table 3] below.

[Table 3]

As shown in Table 3, the best treatment efficiency was shown in the electrode plate coated with iridium and platinum in a ratio of 68:32.

Therefore, for the electrode plate, it is preferable that the coating ratio of iridium and platinum on the titanium substrate is in the range of 60:40 to 80:20, and most preferably, it is wastewater to make the composite coating close to the ratio of 68:32. It is possible to increase the decomposition efficiency of nitrogenous substances in the interior.

[Experimental Example 3]

In Experimental Example 2, an electrode plate coated with iryrium and platinum on a titanium substrate at a ratio of 68:32, which showed high processing efficiency, was operated in the same manner as in Experimental Example 1.

By changing the conductivity and treatment time of the wastewater, the treatment efficiency of TN concentration, ammonia nitrogen concentration and nitrate nitrogen concentration were measured.

The measured values of the initial wastewater raw water are shown in [Table 4] below.

[Table 4]

The conductivity was changed by adding NaCl as an oxidation promoter, and the residence time of the electrolyzer was measured by dividing it into 2 minutes and 4 minutes, and the results are shown in Tables 5 and 6 below.

[Table 5]

[Table 6]

As can be seen from the results of Tables 5 and 6, when the electrolysis reaction was performed with the conductivity set to 6, the treatment efficiency was higher. Although not indicated, if the conductivity is set to 7, the increase in treatment efficiency was insufficient compared to the conductivity 6 .

In addition, in the residence time, the treatment efficiency was higher at 4 minutes than at 2 minutes, and in the other experimental data, the treatment efficiency increased up to 5 minutes, but the effect of increasing the treatment efficiency was insignificant at a time longer than that. Therefore, in terms of efficiency compared to power consumption, it is desirable to conduct the electrolysis for 3 to 5 minutes to achieve the decomposition reaction.

10: wastewater treatment system
20: catchment tank
30: pretreatment tank
31: inlet part 32: stirring part
33: bulkhead
40: oxidation promoter storage tank
50: stay group
51: exhaust line
60: electrolysis device
61: wastewater electrolysis supply pipe 62: electrolyzer
63: wastewater electrolysis discharge pipe 64: electrolyte body
65: electrode plate
641: decomposition reaction chamber 642: inlet
643: outlet
70: control unit
* Non-city code: 70

Claims (8)

In the electrode plate for wastewater treatment that electrolyzes and removes wastewater containing a large amount of nitrogen-based components,
An electrode plate for wastewater treatment, characterized in that it is made by complex coating a titanium substrate with a (iridium:platinum) ratio of (60:40) to (80:20). According to claim 1,
The electrode plate for wastewater treatment, wherein the coating ratio of iridium and platinum on the titanium substrate is 68:32. In the wastewater treatment system for electrolysis and removal of wastewater containing a large amount of nitrogen-based components,
a water collecting tank 20 for introducing and storing wastewater containing a large amount of nitrogen-based components;
a pretreatment tank 30 for mixing and stirring an oxidation promoter into the wastewater introduced from the water collecting tank to adjust the conductivity to promote the electrolysis reaction of the wastewater;
an oxidation promoter storage tank 40 for storing the oxidation promoter supplied to the pretreatment tank;
a retention tank 50 that receives and temporarily stores wastewater with conductivity adjusted from the pretreatment tank, and is equipped with a conductivity sensor;
The wastewater electrolysis supply pipe 61 that receives the wastewater whose conductivity is controlled from the retention tank, and the wastewater is introduced through the wastewater electrolysis supply pipe, and the nitrogen-based component is electrolyzed and removed by a plurality of built-in electrode plates 65. The electrode plate includes an electrolytic cell 62 formed by complex coating a titanium substrate with a (iridium:platinum) ratio of (60:40) to (80:20), and wastewater electrolysis for discharging the electrolyzed wastewater from the electrolyzer. an electrolysis device 60 composed of a discharge pipe 63;
A nitrogen-based wastewater treatment system comprising a; a control unit 70 for intermittent control flow. 4. The method of claim 3,
The electrolyzer 62 of the electrolysis device 60 is,
A plate-shaped decomposition reaction chamber 641 is formed inside in the vertical direction, an inlet 642 through which wastewater is introduced is formed on the lower rear surface, and an outlet 643 for discharging the electrolyzed wastewater is formed on the upper rear surface. a plate-shaped electrolytic body 64 disposed vertically;
A plurality of electrode plates 65 installed in the decomposition reaction chamber inside the electrolytic body and installed in multiple layers in the front and rear directions in the space between the lower inlet and the upper outlet, spaced apart from each other, and connected so that the anode and the cathode cross each other; A nitrogen-based wastewater treatment system, characterized in that it is configured. 5. The method of claim 4,
The electrolysis device 60,
A nitrogen-based wastewater treatment system, characterized in that a plurality of electrolyzers 62 are connected in series or parallel or series and parallel to increase the decomposition treatment rate of nitrogen-based components by electrolysis or increase the treatment amount. In the operating method of the nitrogen-based wastewater treatment system according to claim 3,
a wastewater storage step of storing wastewater containing a large amount of nitrogen-based components in a water collecting tank;
an oxidation promoter mixing step of supplying wastewater from the water collection tank to the pretreatment tank, and further adding an oxidation promoter in the oxidation promoter storage tank and stirring;
The wastewater mixed with the oxidation promoter in the pretreatment tank is transferred to the retention tank, and if the conductivity measured by the conductivity sensor of the retention tank is low compared to the conductivity set in the control unit, an oxidation promoter is added. Conductivity matching and equalization step of adding more to match the conductivity, and temporarily storing before input to the process to be described later to equalize the conductivity;
The nitrogen-based component electrolysis step in which the wastewater of the retention tank is introduced into the lower part of the electrolytic cell in which the electrode plates, which are vertical plates, are arranged in multiple rows, passes between the electrode plates, and moves to the upper part, where an electrolysis reaction occurs, decomposing and discharging nitrogen-based components in the wastewater ; Nitrogen-based wastewater treatment system operating method comprising the. 7. The method of claim 6,
In the nitrogen-based component electrolysis step,
Multi-stage passing through an electrolyzer to increase the treatment rate of nitrogen-based wastewater by connecting a plurality of electrolyzers in series; or a wastewater dispersion treatment step of increasing the amount of nitrogen-based wastewater treated by connecting a plurality of electrolyzers in parallel; Nitrogen-based wastewater treatment system operating method, characterized in that either one or both are made. 7. The method of claim 6,
In the oxidation promoter mixing step, the stirring time is set to 10 to 30 minutes,
In the conductivity matching and homogenization step, the conductivity of the wastewater is formed at 4 to 8 (S/m), and is homogenized by staying for 30 to 60 minutes,
In the nitrogen-based component electrolysis step, a nitrogen-based wastewater treatment system operating method, characterized in that the electrolysis is performed by moving the wastewater so that the residence time is 1 to 5 minutes per one electrolyzer.

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