Apparatus, System, and Method for Treating Industrial Wastewater

Abstract

A wastewater treatment device according to one embodiment of the present invention includes a reaction vessel that receives waste liquid and performs Fenton oxidation, a heat exchanger that recovers heat generated in the reaction vessel, a sensing unit that senses the temperature of the reaction vessel, and a control unit that controls the heat exchanger using the sensing value of the sensing unit.

Description

Technology Field

[0001] The present invention relates to an industrial wastewater treatment device, an industrial wastewater treatment system, and an industrial wastewater treatment method. Background Technology

[0002] Complex contaminants contained in wastewater generated during semiconductor processes can cause acute toxicity in biological treatment processes, thereby impairing process stability. Although advanced oxidation technologies such as Fenton are being introduced to treat this industrial wastewater, they have the disadvantage of increasing the amount of sludge generated due to the excessive input of external hydrogen peroxide and iron salts.

[0003] To overcome these operational difficulties, Mechanical Vapor Recompression (MVR) evaporation concentration technology has recently been introduced, with attempts being made to improve energy efficiency compared to the existing Thermal Vapor Recompression (TVR) method. However, securing economic viability is difficult due to the rapid rise in energy unit costs and increased outsourcing costs for the treatment of concentrates; furthermore, the operational stability of in-house treatment for high-concentration wastewater is deteriorating due to the complexity of controlling the concentration rate and the scaling issues that occur upon failure.

[0004] The oxidation efficiency may be affected by the temperature of the reaction tank where the oxidation reaction of wastewater takes place, and if the temperature of the reaction tank becomes excessively runaway, there is a problem of reduced oxidation efficiency and stability. Prior art literature

[0005] Registered Patent Publication No. 10-0754843 The problem to be solved

[0006] The technical problem that the present invention aims to solve is to provide an industrial wastewater treatment device, an industrial wastewater treatment system, and an industrial wastewater treatment method that increase oxidation efficiency and stability. means of solving the problem

[0007] To solve the above technical problem, an industrial wastewater treatment device according to one embodiment of the present invention comprises: a reaction vessel in which waste liquid is supplied and Fenton oxidation is performed; a heat exchanger for recovering heat generated in the reaction vessel; a sensing unit for sensing the temperature of the reaction vessel; and a control unit for controlling the heat exchanger using the sensing value of the sensing unit.

[0008] In addition, the control unit can determine the state of the reaction vessel according to the temperature of the reaction vessel and control the heat exchanger according to the state of the reaction vessel.

[0009] In addition, the control unit may control the heat exchanger so that the amount of heat recovered by the heat exchanger becomes less than or equal to the first value when the temperature of the reaction vessel is less than or equal to the first reference value, control the heat exchanger to a normal state when the temperature of the reaction vessel is greater than or equal to the first reference value or less than the second reference value, and increase the amount of heat recovered by the heat exchanger in stages when the temperature of the reaction vessel is greater than or equal to the second reference value.

[0010] Additionally, the sensing unit may include a first sensing unit for sensing the temperature of the reaction vessel; and a second sensing unit for sensing the temperature of the heat exchanger.

[0011] Additionally, the first sensing unit may include a first-1 sensing unit for sensing the temperature of the upper part of the reaction vessel; a first-2 sensing unit for sensing the temperature of the central part of the reaction vessel; and a first-3 sensing unit for sensing the temperature of the lower part of the reaction vessel.

[0012] Additionally, the heat exchanger includes an inlet through which a heat exchange medium flows in and an outlet through which the heat exchange medium flows out, and the second sensing unit may include a second-1 sensing unit for sensing the temperature of the inlet of the heat exchanger; and a second-2 sensing unit for sensing the temperature of the outlet of the heat exchanger.

[0013] Additionally, the second sensing unit may include a second-third sensing unit for sensing the pressure at the inlet of the heat exchange unit; and a second-fourth sensing unit for sensing the pressure at the outlet of the heat exchange unit.

[0014] In addition, when the temperature of the reaction tank is above a third reference value, it may include an emergency collection tank in which at least a portion of the waste liquid stored in the reaction tank is transferred.

[0015] In addition, the control unit may, when the temperature of the reaction tank is above the third reference value, cut off the supply of waste liquid to the reaction tank and open an emergency transfer line to transfer at least a portion of the waste liquid stored in the reaction tank to an emergency collection tank.

[0016] In addition, the above emergency collection tank may include a dilution water inlet for introducing dilution water into the waste liquid being transferred.

[0017] In addition, the sensing unit may include a third sensing unit for measuring the temperature of the emergency water collection tank.

[0018] In addition, the sensing unit may include a fourth sensing unit that measures the temperature of a heat load receiving heat recovered from the heat exchange unit.

[0019] In addition, the above heat load may include an evaporative concentrate water tank.

[0020] In addition, the sensing unit may include a fifth sensing unit for measuring at least one of the total organic carbon amount, redox potential, and pH of the reaction vessel.

[0021] To solve the above technical problem, an industrial wastewater treatment system according to one embodiment of the present invention comprises: a waste liquid supply unit that supplies a waste liquid containing permanganate and a waste liquid containing hydrogen peroxide; a chemical injection unit that introduces iron salt, caustic soda, and quicklime; a mixing unit in which the waste liquid containing permanganate and the waste liquid containing hydrogen peroxide supplied from the waste liquid supply unit are mixed with the iron salt, caustic soda, and quicklime supplied from the chemical injection unit to perform Fenton oxidation and primary heavy metal coagulation; and a coagulation tank in which a polymer is introduced into the mixed waste liquid supplied from the mixing unit and secondary heavy metal coagulation is performed.

[0022] Additionally, the mixing unit may include a heat exchanger that receives waste liquid and includes a reaction vessel in which Fenton oxidation is performed, and recovers heat generated in the reaction vessel; a sensing unit that senses the temperature of the reaction vessel; and a control unit that controls the heat exchanger using the sensing value of the sensing unit.

[0023] To solve the above technical problem, an industrial wastewater treatment method according to one embodiment of the present invention comprises an industrial wastewater treatment device comprising a reaction vessel in which wastewater is supplied and Fenton oxidation is performed, and a heat exchanger for recovering heat generated in the reaction vessel, the method comprising: a step of sensing the temperature of the reaction vessel; and a step of controlling the heat exchanger using the temperature of the reaction vessel.

[0024] In addition, the method includes a step of determining the state of the reaction vessel according to the temperature of the reaction vessel, and can control the heat exchanger according to the state of the reaction vessel.

[0025] Additionally, the step of controlling the heat exchanger may include: a step of controlling the heat exchanger so that the amount of heat recovered by the heat exchanger becomes less than or equal to the first value when the temperature of the reaction vessel is less than the first reference value; a step of controlling the heat exchanger to a normal state when the temperature of the reaction vessel is greater than or equal to the first reference value or less than the second reference value; a step of gradually increasing the amount of heat recovered by the heat exchanger when the temperature of the reaction vessel is greater than or equal to the second reference value or less than the third reference value; and a step of transferring at least a portion of the waste liquid stored in the reaction vessel to an emergency collection tank when the temperature of the reaction vessel is greater than or equal to the third reference value.

[0026] In addition, the method may include a step of introducing diluted water into the emergency water collection tank.

[0027] In addition, the method may include a step of blocking the supply of waste liquid to the reaction vessel when the temperature of the reaction vessel is greater than or equal to the third reference value. Effects of the invention

[0028] According to the present embodiment, it is possible to simultaneously achieve prevention of runaway and maintenance of oxidation efficiency. By comprehensively measuring and determining the reaction temperature, the rate of temperature rise (dT / dt), the oxidation-reduction potential (ORP), the deviation between multiple temperature sensors, and the TOC removal rate, the precursor state of runaway in the Fenton reaction can be detected early. Accordingly, rather than simply blocking the process after the temperature has exceeded the limit, preventive control is possible before the process transitions to runaway, thereby significantly improving process safety.

[0029] In addition, as the reaction temperature rises, hydrogen peroxide is consumed in a self-decomposition reaction rather than an effective oxidation reaction, and by performing control before a decrease in oxidation efficiency occurs, the effectiveness of Fenton oxidation can be stably maintained.

[0030] Furthermore, by not treating the heat generated in the oxidation reaction as a single risk factor and by distinguishing and controlling the manageable heat associated with effective oxidation and the unproductive heat generated by auto-decomposition, it is possible to utilize or manage the reaction heat in the normal oxidation phase and actively suppress the reaction heat in the auto-decomposition-dominated or runaway-precursor phase, thereby achieving both safety and treatment efficiency simultaneously.

[0031] By utilizing the external heat load process as a heat demand source in normal conditions and switching it to a heat sink in abnormal conditions, and by activating an emergency water collection tank-based cooling loop when necessary, a multi-layer protection structure with clearly separated energy utilization and safety control can be provided.

[0032] In addition, the cost of oxidizers and handling risks can be reduced by eliminating the need for external hydrogen peroxide input, and chemical input costs can be reduced by using ferric sulfate or ferrous sulfate. The Fenton reaction can be accelerated by utilizing manganese ions in the permanganate wastewater, thereby increasing the removal efficiency based on TOC (Total Organic Carbon). Furthermore, by removing formaldehyde and tartaric acid—which form chelate compounds with heavy metals among the TOC components in the wastewater—through wastewater mixing and the Fenton reaction, the heavy metal removal rate during the coagulation and sedimentation stage can be increased. Additionally, the treated water entering the biological process becomes low-molecular-weight and non-toxic through the Fenton reaction, achieving a biodegradability level comparable to methanol, which can increase the operational efficiency of the biological process. By optimizing the amount of sludge generated, it is possible to achieve a copper (Cu) content of ≥6 wt% (based on dry weight) in the sludge, making it available for sale. This results in resource recycling and increased revenue. Additionally, by utilizing the exothermic reaction generated in the Fenton reaction to preheat raw water used for evaporation and concentration or supply it to other heat sources within the workplace, it is possible to achieve energy savings and improve the self-sufficiency rate of heat sources.

[0033] By effectively pretreating toxic substances, such as heavy metals and oxidizers, contained in waste liquid, the efficiency of biological treatment—the final stage of discharge—is increased, and environmental pollution can be reduced by preventing the discharge of toxic substances. Brief explanation of the drawing

[0034] FIG. 1 is a block diagram of a wastewater treatment device according to one embodiment of the present invention. FIGS. 2 and FIGS. 3 are block diagrams of a wastewater treatment device according to an embodiment of the present invention. FIG. 4 is a diagram illustrating the process of determining the state according to the temperature of the reaction tank of a wastewater treatment device according to an embodiment of the present invention. FIG. 5 is a block diagram of a wastewater treatment system according to one embodiment of the present invention. FIGS. 6 and 7 are drawings for explaining the process of a wastewater treatment system according to an embodiment of the present invention. FIG. 8 is a flowchart of a wastewater treatment method according to one embodiment of the present invention. FIGS. 9 to 12 are flowcharts of a wastewater treatment method according to an embodiment of the present invention. FIGS. 13 to 17 are flowcharts of a wastewater treatment method in a wastewater treatment system according to an embodiment of the present invention. Specific details for implementing the invention

[0035] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings.

[0036] However, the technical concept of the present invention is not limited to some of the described embodiments but can be implemented in various different forms, and within the scope of the technical concept of the present invention, one or more of the components among the embodiments may be selectively combined or substituted.

[0037] In addition, terms used in the embodiments of the present invention (including technical and scientific terms) may be interpreted in a sense that is generally understood by those skilled in the art to which the present invention belongs, unless explicitly and specifically defined otherwise. Terms that are commonly used, such as terms defined in advance, may be interpreted in consideration of their meaning in the context of the relevant technology.

[0038] Additionally, the terms used in the embodiments of the present invention are for describing the embodiments and are not intended to limit the present invention. In this specification, the singular form may include the plural form unless specifically stated otherwise in the text, and when described as “at least one of A and B and C (or more than one),” it may include one or more of all combinations that can be combined with A, B, and C.

[0039] In addition, terms such as first, second, A, B, (a), (b), etc. may be used to describe the components of the embodiments of the present invention.

[0040] These terms are intended merely to distinguish a component from other components and are not limited by the nature, order, sequence, etc., of the said component.

[0041] And, where it is stated that a component is 'connected', 'combined', or 'joined' to another component, this may include not only cases where the component is directly connected, combined, or joined to the other component, but also cases where it is 'connected', 'combined', or 'joined' due to another component located between the component and the other component.

[0042] Furthermore, when described as being formed or placed "above or below" each component, "above" or "below" includes not only cases where two components are in direct contact with each other, but also cases where one or more other components are formed or placed between the two components. Additionally, when expressed as "above or below," it may include the meaning of a downward direction as well as an upward direction relative to a single component.

[0043] In addition, the expression that configuration A is positioned between configuration B and configuration C must include the meaning that configuration A is positioned such that at least a portion of it overlaps with configurations B and C in the horizontal and / or vertical directions.

[0044] Expressions referring to directions include horizontal and vertical directions, and the horizontal direction includes a first horizontal direction and a second horizontal direction perpendicular to the first horizontal direction. These are referred to as the first horizontal direction (X-axis), the second horizontal direction (Y-axis), and the vertical direction (Z-axis) according to the Cartesian coordinate system, and the meaning of being superimposed along the horizontal direction must include the meaning of being superimposed along the first horizontal direction and / or superimposed along the second horizontal direction.

[0045] Furthermore, the statement that Configuration A is exposed from Configuration B should be understood as meaning that Configuration A is exposed from Configuration B, not that Configuration A is exposed from the claimed product. In other words, if Configuration A is stated to be exposed from Configuration B, it should be understood to mean that Configuration A is not exposed from the claimed product by Configuration C other than Configuration B.

[0046] Furthermore, when it is stated that Component A 'contacts' Component B, this may include not only cases where the component 'contacts' the other component directly, but also cases where it 'contacts' due to another component located between the component and the other component. Therefore, if Component A is to be understood only as 'directly contacting' Component B, it is described as 'directly contacting'.

[0047] In addition, when it is stated that configuration A is 'covered' by configuration B, it should be understood that configuration A is covered by configuration B, and considering the function and purpose to be solved, at least a portion of configuration A is covered by configuration B, and unless otherwise specifically stated, it should not be understood that the entire configuration A is covered by configuration B.

[0049] FIG. 1 is a block diagram of a wastewater treatment device according to one embodiment of the present invention, FIG. 2 and FIG. 3 are block diagrams of a wastewater treatment device according to an embodiment of the present invention, and FIG. 4 is a diagram for explaining a process of determining the state according to the temperature of a reaction tank of a wastewater treatment device according to an embodiment of the present invention.

[0050] A wastewater treatment device (10) according to an embodiment of the present invention is composed of a reaction tank (11), a heat exchanger (12), a sensing unit (13), and a control unit (14), and may include an emergency water collection tank (15), a dilution water input unit (16), and a chemical input unit (not shown).

[0051] The reaction tank (11) receives waste liquid. A Fenton or Fenton-like reaction may occur in the waste liquid supplied within the reaction tank (11). The waste liquid supplied to the reaction tank (11) may include waste liquid containing hydrogen peroxide. Additionally, the waste liquid supplied to the reaction tank (11) may include waste liquid containing permanganate, and may include mixed waste liquid in which waste liquid containing hydrogen peroxide and waste liquid containing permanganate are mixed.

[0052] In the reaction tank (11), an oxidation reaction of the waste liquid may occur, and Fenton oxidation or a Fenton-like reaction may occur. Iron salt may be introduced into the reaction tank (11). Iron salt may be introduced from the chemical injection part. Here, the iron salt may contain Fe(III) and may contain ferric sulfate (Fe2(SO4)3). Or, it may contain ferrous sulfate (FeSO4). In addition, it may contain ferric chloride (FeCl3) and ferrous chloride (FeCl2). In addition, sulfuric acid may be introduced if necessary. The amount of iron salt introduced may be 5.5 to 16.7% or 5 to 20% of the total organic carbon (TOC) contained in the waste liquid. For example, if the TOC of the mixed wastewater is 5,000 ppm, 279 to 838 ppm of Fe may be introduced.

[0053] OH radicals (hydroxyl radicals), which are powerful oxidizing agents, can be generated by iron salts from hydrogen peroxide contained in waste liquids containing hydrogen peroxide. Hydroxyl radicals can contribute to the oxidation of organic matter.

[0054] Additionally, caustic soda may be introduced into the reaction vessel (11). Caustic soda can be introduced as NaOH to optimize the Fenton reaction. By introducing caustic soda, the acidity of the waste liquid can be adjusted to a pH range of 2 to 4. By introducing caustic soda, the conversion of Fe(III) to Fe(II) by the manganese (Mn(II)) ions in the waste liquid is accelerated, and the generation of OH radicals (hydroxyl radicals), which are powerful oxidizing agents, from hydrogen peroxide can be accelerated. For Fenton oxidation, the Fenton oxidation reaction can be induced even if ferric sulfate (Fe2(SO4)3) is used instead of ferrous chloride (FeCl2).

[0055] If the composition of the waste liquid introduced into the reaction tank (11) changes and the concentration of hydrogen peroxide in the waste liquid increases, the reaction rate inside the reaction tank (11) increases rapidly, amplifying the heat generation and causing a risk of runaway reaction where the reaction temperature rises rapidly in a short period of time. In an environment where the temperature of the reaction tank (11) is high, a state of self-decomposition dominance over hydrogen peroxide may occur. Here, a state of self-decomposition dominance may be a state in which the reaction pathway in which heat is generated by decomposition into water and oxygen acts dominantly over the reaction pathway in which hydroxyl radicals are generated from hydrogen peroxide. In this case, hydrogen peroxide generates only reaction heat and does not substantially contribute to the oxidation of organic matter, which may result in a problem where the total organic carbon removal rate decreases. Therefore, it is necessary to efficiently control the temperature of the reaction tank (11) to increase the oxidation efficiency of the reaction tank (11).

[0056] In addition, excessive runaway water increases the risk of safety accidents such as pressure increase, increased bubbles, and device damage inside the reaction tank (11), and can cause instability in the wastewater treatment process. Therefore, in order to increase stability, it is necessary to control the temperature of the reaction tank (11).

[0057] Heat is generated during the oxidation reaction in the reaction tank (11), and the heat exchanger (12) recovers the heat generated in the reaction tank (11). The temperature of the reaction tank (11) can be efficiently controlled using the heat exchanger (12). The heat exchanger (12) may include a plate / shell-and-tube type heat exchanger. Alternatively, it may include a plate heat exchanger or a shell-and-tube heat exchanger. The heat exchanger (12) can supply the heat recovered through heat exchange to a heat load (20) that requires heat. Here, the heat load (20) may include an evaporative concentrate source tank. The heat recovered from the heat exchanger (12) can be used to preheat raw water fed into an evaporative concentrater (MVR / TVR) of another wastewater stream, or can be supplied to other heat sources required within the workplace, thereby improving energy savings and heat source self-sufficiency.

[0058] The sensing unit (13) senses the temperature of the reaction vessel (11). The sensing unit (13) may include a temperature sensor. Additionally, the sensing unit (13) may include a sensor for measuring total organic carbon (TOC), oxidation-reduction potential (ORP), pH, pressure, etc. The sensing unit (13) will be described in detail later.

[0059] The control unit (14) controls the heat exchange unit (12) using the sensing value of the sensing unit (13). The control unit (14) can control each component of the wastewater treatment device.

[0060] The control unit (14) may include one or more processors and one or more memories. The processor can control the wastewater treatment device by executing instructions for the control logic of the wastewater treatment method stored in the memory. The control unit (14) may be implemented as a program including instructions for controlling the processor to execute the control logic. The program may be provided by being stored on a computer-readable recording medium.

[0061] The control unit (14) can control the heat exchange unit (12) using the sensing value sensed by the sensing unit (13) to increase oxidation efficiency and stability. The control unit (14) can determine the state of the reaction vessel (11) according to the temperature of the reaction vessel (11). The control unit (14) can control the heat exchange unit (12) according to the determined state of the reaction vessel (11). The control unit (14) can control the heat recovery amount by controlling the operation of the heat exchange unit (12) or by controlling its operation.

[0062] The control unit (14) can control the heat exchange unit (12) according to the temperature range of the reaction vessel (11).

[0063] The lower the temperature of the reaction vessel (11), the more the self-decomposition of hydrogen peroxide is suppressed; however, if the temperature is excessively low, the rate of hydroxyl radical generation and reaction rate decrease, which may reduce oxidation efficiency. Conversely, if the temperature of the reaction vessel (11) rises excessively, the self-decomposition of hydrogen peroxide occurs predominantly, and hydrogen peroxide is consumed in a way that does not contribute to oxidation, and the risk of runaway is increased. By taking into account this trade-off relationship with temperature and controlling the amount of heat recovered and the heat transfer path, reaction safety and oxidation efficiency can be secured simultaneously.

[0064] When the temperature of the reaction vessel (11) is below a first reference value, the control unit (14) can control the heat exchanger (12) so that the amount of heat recovered by the heat exchanger (12) becomes less than or equal to the first value. The control unit (14) can determine that the case where the temperature of the reaction vessel (11) is below the first reference value is a first state or a state of reduced efficiency. Here, the first reference value may be set as the minimum temperature for maintaining oxidation efficiency. The first reference value may be set through simulation based on the size of the reaction vessel (11), the type of waste liquid supplied to the reaction vessel (11), etc., or may be set by a user. For example, the first reference value may be 30 degrees Celsius. When the temperature of the reaction vessel (11) is below the first reference value, the heat of the reaction vessel (11) is in a low state, so the control unit (14) may stop the operation of the heat exchanger (12) to control the heat recovery amount to 0, or control the heat recovery amount of the heat exchanger (12) to be less than or equal to the first value to suppress heat recovery. Here, the first value may be set according to the temperature of the reaction vessel (11), the heat recovery amount per hour of the heat exchanger (12), etc., and may be set by the user.

[0065] When the temperature of the reaction vessel (11) is greater than or equal to a first reference value and less than a second reference value, the control unit (14) can control the heat exchanger (12) to a normal state. The control unit (14) can determine that the case where the temperature of the reaction vessel (11) is greater than or equal to a first reference value and less than a second reference value is a second state or a normal state. Here, normal state control may mean a state in which the temperature of the reaction vessel (11) is maintained or the range of temperature change is limited to within a certain range. The second reference value may be set as the maximum temperature for maintaining oxidation efficiency. The second reference value may be set through simulation or by a user depending on the size of the reaction vessel (11), the type of waste liquid supplied to the reaction vessel (11), etc. For example, the second reference value may be 40 degrees Celsius. Since oxidation occurs normally in the range between the first reference value and the second reference value, the control unit (14) can control the heat exchange unit (12) to maintain the temperature of the reaction vessel (11) in that range.

[0066] When the temperature of the reaction tank (11) is above the second reference value, the control unit (14) can increase the heat recovery amount of the heat exchanger (12) in stages. When the temperature of the reaction tank (11) is above the second reference value but below the third reference value, the control unit (14) can increase the heat recovery amount of the heat exchanger (12) in stages. The control unit (14) can determine that the case where the temperature of the reaction tank (11) is above the second reference value but below the third reference value is a third state or a preventive switching state. When the temperature of the reaction tank (11) is above the second reference value, it is a section where there is a risk of runaway occurring, and the control unit (14) can increase the heat recovery amount of the heat exchanger (12) to control the temperature of the reaction tank (11) so that it becomes below the second reference value. When the temperature of the reaction vessel (11) increases, the reaction progress per unit time increases, and the heat generation increases. Since the increased heat generation forms a positive feedback structure that raises the temperature of the reaction vessel (11) again, it can lead to runaway. Therefore, the control unit (14) can preventively increase the heat recovery amount of the heat exchanger (12) in stages to suppress the runaway transition in advance. Alternatively, the control unit (14) can control the heat recovery amount of the heat exchanger (12) to the maximum.

[0067] When the temperature of the reaction tank (11) is above the third reference value, the control unit (14) can operate the emergency water collection tank (15). The control unit (14) can determine that when the temperature of the reaction tank (11) is above the third reference value, it is a fourth state or a runaway state. The third reference value can be set to a temperature at which the temperature rise of the reaction tank (11) cannot be suppressed by the maximum heat recovery amount of the heat exchanger (12), and can be set through simulation or by a user depending on the size of the reaction tank (11), the type of waste liquid supplied to the reaction tank (11), the maximum heat recovery amount of the heat exchanger (12), etc. For example, the third reference value may be 45 degrees Celsius. When the temperature of the reaction tank (11) is above the third reference value, the heat of the reaction tank (11) is in a state corresponding to excessive runaway, so stability can be increased by using an emergency water collection tank (15) instead of controlling using a heat exchanger (12).

[0068] The emergency collection tank (15) can store at least a portion of the waste liquid stored in the reaction tank (11). The emergency collection tank (15) is connected to the reaction tank (11) via an emergency line, and in an emergency state of overflow, the emergency line is opened so that at least a portion of the waste liquid stored in the reaction tank (11) can be transferred to the emergency collection tank (15). The waste liquid in which the reaction is incomplete in the reaction tank (11) can be quickly transferred to the emergency collection tank (15) to physically separate the reaction and stop the reaction. The emergency collection tank (15) is formed close to the inlet area where the waste liquid from the reaction tank (11) is supplied, so that the waste liquid incomplete in the reaction can be quickly separated.

[0069] The emergency collection tank (15) may include a dilution water inlet (16) for introducing dilution water into the waste liquid being transported. Here, the dilution water can substantially stop the oxidation reaction by reducing the heat of reaction, lowering the concentration of hydrogen peroxide, and lowering the concentration of reactants. The dilution water may include industrial water, process water, or dilution water equivalent thereto. The emergency collection tank (15) may include a stirring means for uniform dilution and heat dispersion of the waste liquid.

[0070] When the temperature of the reaction tank (11) is above a third reference value, the control unit (14) may cut off the supply of waste liquid to the reaction tank (11) and open an emergency transfer line to transfer at least a portion of the waste liquid stored in the reaction tank (11) to the emergency collection tank (15). The control unit (14) may cut off the supply of waste liquid to the reaction tank (11) and transfer the waste liquid stored in the reaction tank (11) to the emergency collection tank (15) to reduce or empty the waste liquid in which the oxidation reaction occurs in the reaction tank (11). The emergency transfer line may be equipped with a cooling means so that cooling occurs when transferring to the emergency collection tank (15). Here, the cooling means of the emergency transfer line may include a flow path or a heat sink, etc.

[0071] When the temperature of the reaction tank (11) is above the third reference value, the control unit (14) can control the heat recovery amount of the heat exchange unit (12) to the maximum and at the same time transfer the waste liquid of the reaction tank (11) to the emergency collection tank (15). By using the heat exchange unit (12) and the emergency collection tank (15) simultaneously, the stability of the process can be maintained with the highest priority.

[0072] As described above, the control unit (14) can control the heat exchange unit (12) and the emergency water collection tank (15) according to the temperature of the reaction tank (11) to increase oxidation efficiency and stability.

[0073] The sensing unit (13) may include a first sensing unit that senses the temperature of the reaction vessel (11) as well as a second sensing unit that senses the temperature of the heat exchange unit (12).

[0074] The first sensing unit may include a plurality of first sensing units to increase the accuracy of temperature sensing of the reaction vessel (11) and to precisely sense local temperature rise, etc. The first sensing unit may include three or more sensing units.

[0075] The first sensing unit may include a first-1 sensing unit for sensing the temperature of the upper part of the reaction tank, a first-2 sensing unit for sensing the temperature of the central part of the reaction tank, and a first-3 sensing unit for sensing the temperature of the lower part of the reaction tank. By using a plurality of sensing units to sense the temperature, the temperature can be accurately sensed, and the temperatures of the upper, central, and lower parts may differ depending on the size of the reaction tank (11), the degree of stirring of the waste liquid, etc., so that localized runaway can be detected in advance and prevented from spreading to the whole. To this end, as shown in FIG. 3, the first sensing unit may include a first-1 sensing unit (T1) for sensing the temperature of the upper part of the reaction tank (11), a first-2 sensing unit (T2) for sensing the temperature of the central part of the reaction tank (11), and a first-3 sensing unit (T3) for sensing the temperature of the lower part of the reaction tank (11).

[0076] The control unit (14) can calculate a representative reaction temperature (T_rep) and a temperature change rate (dT / dt) using a temperature signal sensed by a sensing unit including a plurality of temperature sensors. Here, the representative reaction temperature can be defined as the maximum value or weighted average value among the plurality of temperature sensors, and the temperature change rate can be calculated as the rate of change of the representative reaction temperature over time.

[0077] The heat exchanger (12) may include an inlet through which a heat exchange medium flows in and an outlet through which the heat exchange medium flows out. The second sensing unit may include a second-1 sensing unit that senses the temperature of the inlet of the heat exchanger (12) and a second-2 sensing unit that senses the temperature of the outlet of the heat exchanger (12). The heat exchanger (12) can recover heat from the reaction tank (11) using a heat exchange medium that passes through a flow path, such as water. To calculate the amount of heat recovered by the heat exchanger (12), the temperature of the inlet through which the heat exchange medium flows in and the temperature of the outlet through which the heat exchange medium flows out are measured, respectively, and the amount of heat recovered can be calculated using the difference between the two temperatures. To this end, as shown in FIG. 3, the second sensing unit may include a second-1 sensing unit (Th1) that senses the temperature of the inlet of the heat exchanger (12) and a second-2 sensing unit (Th2) that senses the temperature of the outlet of the heat exchanger (12). The control unit (14) can calculate the amount of heat recovered by the heat exchange unit (12) based on the difference in the sensing values ​​of the 2-1 sensing unit and the 2-2 sensing unit, the hourly flow rate of the heat exchange medium, and the temperature change rate.

[0078] The second sensing unit may include a second-3 sensing unit that senses the pressure at the inlet of the heat exchanger (12) and a second-4 sensing unit that senses the pressure at the outlet of the heat exchanger (12). In order to determine whether heat recovery of the heat exchanger (12) is performed normally, the pressures at the inlet and outlet may be sensed. As shown in FIG. 3, the second sensing unit may include a second-3 sensing unit (P1) that senses the pressure at the inlet of the heat exchanger (12) and a second-4 sensing unit (P2) that senses the pressure at the outlet of the heat exchanger (12). The control unit (14) calculates a pressure difference ΔP based on the sensing values ​​of the second-3 sensing unit and the second-4 sensing unit, and if the pressure difference exceeds a preset threshold, it may determine that the heat exchange performance has deteriorated or the flow path is blocked and generate an alarm. In this case, even if the temperature of the reaction tank (11) is not above the third reference value, the control unit (14) can perform the transfer of waste liquid from the reaction tank (11) to the emergency collection tank (15). Additionally, the control unit (14) can block the supply of waste liquid to the reaction tank (11). Through this, stability can be further enhanced.

[0079] The sensing unit (13) may include a third sensing unit for measuring the temperature of the emergency water collection tank (15). When waste liquid is transferred to the emergency water collection tank (15), the control unit (14) may control the amount of diluted water input according to the temperature of the emergency water collection tank (15). As shown in FIG. 3, it may include a third sensing unit (Te) for sensing the temperature of the emergency water collection tank (15). In addition, the third sensing unit may include a plurality of third sensing units to measure local temperatures and, depending on the temperature difference at each location, use a stirring means to ensure that the waste liquid and diluted water inside the emergency water collection tank (15) are well mixed.

[0080] The sensing unit may include a fourth sensing unit that measures the temperature of a heat load (20) that receives heat recovered from a heat exchanger (12). The heat load (20) may include process devices that receive heat recovered from the heat exchanger (12) and utilize it for preheating, etc. It may be configured to operate as a heat load (preheating target) in a normal state and as a heat sink (heat absorption source) in an abnormal state. Examples of the heat load (20) may include an evaporation concentration raw water tank, process water preheating, reactor preheating, and heat medium heating processes. As shown in FIG. 3, it may include a fourth sensing unit (Tr) that senses the temperature of the heat load (20). The control unit (14) expands the heat absorption only when the temperature of the fourth sensing unit is below the allowable upper limit temperature reference value (Tr_max), and when it exceeds the allowable upper limit temperature reference value, the control unit (14) can perform waste liquid transfer from the reaction tank (11) to the emergency collection tank (15) even if the temperature of the reaction tank (11) is not above the third reference value. In addition, the control unit (14) can block the supply of waste liquid to the reaction tank (11). Through this, stability can be further increased.

[0081] The sensing unit (13) may include a fifth sensing unit that measures at least one of the total organic carbon amount, redox potential, and pH of the reaction tank (11). The control unit (14) can comprehensively determine the state of the reaction tank (11) by considering the redox potential (ORP) within the reaction tank (11), the rate of change of ORP (dORP / dt), the temperature deviation (ΔT_max) between multiple temperature sensors, and the total organic carbon removal rate (TOC removal rate) of the treated water. To this end, as shown in FIG. 3, the fifth sensing unit may include a 5-1 sensing unit (TOC1) that measures the total organic carbon amount of the waste liquid, a 5-2 sensing unit (TOC2) that measures the total organic carbon amount of the treated water, a 5-3 sensing unit (ORP1) that measures the redox potential, and a 5-4 sensing unit (pH1) that measures the pH.

[0082] The reaction rate, oxidation efficiency, hydrogen peroxide self-decomposition, and runaway risk according to temperature may be as shown in FIG. 4. From a low temperature to a certain temperature, as the temperature rises, the reaction rate, oxidation efficiency, hydrogen peroxide self-decomposition, and runaway risk all increase. Beyond a certain temperature range, the oxidation efficiency and reaction rate decrease, while the hydrogen peroxide self-decomposition and runaway risk increase. By controlling the temperature of the reaction vessel (11) to be maintained in a range where the reaction rate and oxidation efficiency are high and the hydrogen peroxide self-decomposition and runaway risk are low, the oxidation efficiency and stability can be increased. The temperature range can be classified as a low temperature range in section 41, an optimal temperature range in section 42, and a high temperature risk range in section 43. The control unit (14) can increase oxidation efficiency by controlling the heat exchange unit (12) so that the temperature of the reaction tank (11) can be maintained at level 42, and can increase stability by controlling the heat exchange unit (12) and the emergency water collection tank (15) at level 43.

[0083] The control unit (14) calculates the representative reaction temperature (T_rep) and the temperature rise rate (dT / dt), and determines the state of the reaction tank (11) by comprehensively considering the oxidation-reduction potential (ORP) in the reaction tank, the ORP change rate (dORP / dt), the temperature difference between multiple temperature sensors (ΔT_max), and the total organic carbon removal rate (TOC removal rate) of the treated water, and can perform control corresponding to each state.

[0084] The state of the reaction tank (11) determined by the control unit (14) may include a first state, a second state, a third state, and a fourth state. Alternatively, the state of the reaction tank (11) determined by the control unit (14) may include a reduced efficiency state, a normal state, a preventive switching state, and a runaway state.

[0085] The first state or efficiency reduction state may refer to a state in which the reaction temperature (T_rep) is maintained below a first reference value, which is the lower limit of the target range for maintaining oxidation efficiency, or the reaction temperature falls below the optimal reaction region due to excessive heat recovery, and the oxidation efficiency is reduced as the ORP rise is delayed and the TOC removal rate of the treated water is maintained below a set threshold value. The temperature in the first state or efficiency reduction state may be below the first reference value. Here, the first reference value may be 30 degrees Celsius. At this time, the temperature rise rate is very low, and the temperature of the reaction tank (11) may be 20 to 30 degrees. The ORP and the ORP change rate may be low or the rise is delayed, the deviation of the multiple temperature sensors of the reaction tank (11) is small, and the TOC removal rate may be reduced. In this state, the control unit (14) may control the reaction temperature to return to the optimal range by gradually reducing the amount of heat recovery or limiting the operation of the heat exchange unit. However, in the event that a pH deviation or a sudden change in ORP occurs in the above state, rather than adjusting the heat recovery by controlling the heat exchanger (12), the correction of the oxidation reaction conditions of the reaction vessel (11), the recovery of catalyst activity, or the adjustment of the reactant input conditions may be performed first.

[0086] The second state or steady state may refer to a state in which the representative reaction temperature (T_rep) is located within the target range for maintaining oxidation efficiency, the temperature rise rate (dT / dt) is below a set stability standard, the absolute ORP value and the ORP change rate are maintained stably, and the temperature deviation between multiple temperature sensors is below a preset standard value. The temperature in the second state or steady state may be greater than or equal to the first standard value and less than the second standard value. Here, the second standard value may be 40 degrees Celsius. Additionally, it may include a case in which the TOC removal rate of the treated water is continuously secured at a target level. In this case, the temperature rise rate is low and stable, and the temperature of the reaction tank (11) may be 30 to 40 degrees. The ORP value may be stable within the target range, the ORP change rate may be gradual, the deviation of multiple temperature sensors of the reaction tank (11) is small, and the TOC removal rate may be continuous and stable. The control unit (14) maintains the heat exchange unit (12) in a normal operating state and can transfer the recovered heat to the heat load (20) to perform preheating or energy utilization.

[0087] The third state or preventive switching state may refer to a state where the representative reaction temperature (T_rep) is within the allowable range, but the temperature rise rate (dT / dt) approaches the threshold value, the ORP change rate (dORP / dt) shows a tendency to increase compared to normal, or the temperature deviation between multiple temperature sensors expands. The temperature in the third state or preventive switching state may be greater than or equal to the second reference value and less than the third reference value. Here, the third reference value may be 45 degrees Celsius. At this time, the temperature rise rate may increase gradually or rise rapidly in the short term, and the temperature of the reaction tank (11) may be 38 to 42 degrees. The ORP value may be within the allowable range but is on an upward trend, the ORP change rate is accelerating its increase, the deviation of multiple temperature sensors in the reaction tank (11) shows signs of increasing, and the TOC removal rate may be maintained or slightly slowed down and delayed. When at least one of the above conditions is satisfied, the control unit (14) can gradually increase the amount of heat recovered by the heat exchange unit (12) and, if necessary, maximize it in order to prevent the transition to an overrun.

[0088] The fourth state or runaway state may refer to a case where, despite preventive switching control, the representative reaction temperature (T_rep) rises above the third reference value, which is the stopping temperature, or the temperature rise rate (dT / dt) exceeds the threshold value and at the same time, at least one of the absolute ORP value, the ORP change rate, or the ORP fluctuation range deviates from a preset allowable range. It may also include a case where the temperature deviation between multiple temperature sensors increases rapidly. The temperature in the fourth state or runaway state may be above the third reference value. At this time, the temperature rise rate may rise rapidly or maintain a high value, and the temperature of the reaction tank (11) may be 45 degrees or higher. The ORP value may have an excessively high value or be unstable, the ORP change rate may rise rapidly or be unstable, the deviation of multiple temperature sensors in the reaction tank (11) may increase rapidly, and the TOC removal rate may be slowed down or unstable. In the fourth state, the transfer path of the recovered heat is controlled with the purpose of prioritizing process safety over energy recovery, and the control unit (14) can operate a cooling loop using an emergency collection tank (15) and perform safety control to restrict or block the inflow of waste liquid, etc. into the reaction tank (11).

[0089] The reference values ​​for judging each state are presented as examples, and it is obvious that they may vary depending on the process scale, wastewater composition, reactor volume, and operating conditions.

[0090] FIG. 5 is a block diagram of a wastewater treatment system according to one embodiment of the present invention, and FIG. 6 and FIG. 7 are drawings for explaining the process of a wastewater treatment system according to an embodiment of the present invention.

[0091] A wastewater treatment system according to an embodiment of the present invention includes a waste liquid supply unit (130) and a waste liquid treatment unit (100), and the waste liquid treatment unit (100) may include a Fenton oxidation unit (110) and a chemical injection unit (120). A wastewater treatment system according to an embodiment of the present invention may be a semiconductor wastewater treatment system that treats semiconductor wastewater in a semiconductor manufacturing post-treatment process. Alternatively, it may be an industrial wastewater treatment system that treats industrial wastewater.

[0092] The Fenton oxidation unit (110) may include a reaction tank (111), a coagulation tank (112), a sedimentation tank (113), a concentration tank (114), and a dewatering machine (115), and may include a heat exchange unit (140) and a wastewater treatment unit (150), and may include a control unit (not shown) that controls each component of the industrial wastewater treatment system. Additionally, it may include a sensing unit (not shown) that senses the temperature, pressure, ORP, TOC, etc. of the waste liquid supply unit (130), the Fenton oxidation unit (110), or the chemical injection unit (120). Additionally, it may include a communication module (not shown) that performs communication with the outside, and the communication module may be an IoT-based communication module for remote monitoring and control of the wastewater treatment system.

[0093] Detailed descriptions of the reaction tank (111), heat exchanger (140), sensing unit, and control unit correspond to the configuration of the reaction tank (11), heat exchanger (12), sensing unit (13), and control unit (14) of the wastewater treatment device of FIGS. 1 to 4, and thus redundant descriptions will be omitted below. In addition, each component of the wastewater treatment system of FIGS. 5 to 7 may be included in the wastewater treatment device of FIGS. 1 to 4.

[0094] A wastewater treatment system according to an embodiment of the present invention can be applied to a wastewater treatment process for treating waste liquid generated in a semiconductor or circuit board manufacturing process. A wastewater treatment system according to an embodiment of the present invention may be a system for treating semiconductor wastewater in a semiconductor manufacturing post-processing process.

[0095] Mixed wastewater generated during semiconductor or circuit board manufacturing processes may simultaneously contain high concentrations of recalcitrant organic compounds (e.g., formaldehyde, tartaric acid), heavy metals that cause biological toxicity (e.g., copper, nickel, manganese), and oxidizers (e.g., permanganate, hydrogen peroxide). These complex contaminants can impair process stability by causing acute toxicity in biological treatment processes. In the case of wastewater containing high levels of heavy metals, it can inhibit the activity of microorganisms for biological treatment, which may result in residual recalcitrant organic matter remaining highly toxic. Furthermore, highly toxic intermediates may be generated during the process of decomposing complex contaminants by microorganisms.

[0096] A wastewater treatment system according to an embodiment of the present invention can perform wastewater pretreatment and heat recovery treatment by integrating an in situ Fenton oxidation reaction utilizing residual oxidizing agents in the wastewater without the input of external hydrogen peroxide (H₂O₂), and alkali coagulation and precipitation processes, targeting mixed wastewater containing highly toxic and non-biodegradable organic matter and heavy metals. The system according to an embodiment of the present invention can be used in a semiconductor manufacturing post-treatment process to treat wastewater containing permanganate and hydrogen peroxide generated during the semiconductor manufacturing process. Additionally, it is obvious that it can be used in a process to treat industrial wastewater containing permanganate and hydrogen peroxide.

[0097] The waste liquid supply unit (130) can supply at least one waste liquid containing permanganate (131) and at least one waste liquid containing hydrogen peroxide (132) to the Fenton oxidation unit (110). Multiple waste liquids can be mixed in the reaction tank (111). Alternatively, multiple waste liquids can be mixed in the waste liquid supply unit (130) and supplied to the reaction tank (111).

[0098] The waste liquid supplied and mixed from the waste liquid supply unit (130) may include waste liquid generated in a semiconductor manufacturing process. The waste liquid supplied and mixed from the waste liquid supply unit (130) may include manganese waste liquid (133) and plating waste liquid (134, 135). The manganese waste liquid (133) may, for example, be waste liquid (133) generated in a desmear process. Here, the desmear process is a process for removing 'smear,' which is a residue on the hole wall surface generated during drilling or laser processing, and the smear can be chemically etched by manganese etching. At this time, a permanganate solution may be used, and after manganese etching with the permanganate solution, manganese waste liquid (133) is generated by a washing process, and the manganese waste liquid (133) may contain permanganic acid (131).

[0099] The plating waste liquid may include plating waste liquid (134) generated in the electroplating process and plating waste liquid (135) generated in the chemical plating process. The electroplating process is called electroplating and is a process of applying copper as a thin film using electricity. After the electroplating process, plating waste liquid (134) is generated, and the electroplating waste liquid (134) may include hydrogen peroxide (132), copper, sulfuric acid, and ether-based substances.

[0100] The chemical copper plating process is called electroless plating and is a process of depositing copper as a thin film through a chemical reaction using a reducing agent without using an external power source. After the chemical copper plating process, plating waste liquid (135) is generated, and the chemical copper plating waste liquid (135) may contain formaldehyde, tartaric acid, copper, nickel, caustic soda, etc.

[0101] The mixed waste liquid may contain at least one of formaldehyde, tartaric acid, and formic acid, and at least one of copper, nickel, and manganese.

[0102] When at least one waste liquid containing permanganate (131) and at least one waste liquid containing hydrogen peroxide (132) are mixed, permanganate can be reduced to a manganese (Mn(II)) ion state by hydrogen peroxide (132). At the same time, at least some of the TOC, formaldehyde, formic acid, and tartaric acid in the mixed waste liquid can be oxidized and removed. By mixing the waste liquids, formaldehyde, which can form a chelate compound with iron in the subsequent Fenton oxidation reaction, is removed, thereby minimizing the inhibition reaction that inhibits Fenton oxidation.

[0103] At this time, the acidity of the mixed waste liquid to which the waste liquid is mixed may be pH 3 or lower. Additionally, the acidity of the mixed waste liquid to which the waste liquid is mixed may be pH 2 or lower. At this time, the hydrogen peroxide concentration of the mixed waste water can be controlled to a level below the standard value. At this time, the hydrogen peroxide concentration of the mixed waste water can be controlled to 2% or lower. Alternatively, the hydrogen peroxide concentration of the mixed waste water can be controlled to a range of 1 to 2%. The standard value of the hydrogen peroxide concentration of the mixed waste water can be set by testing or by the user. To this end, the supply amount of waste liquid containing hydrogen peroxide (132) can be controlled.

[0104] After the multiple waste liquids are mixed, an iron salt (124) can be introduced from the chemical injection unit (120) into the reaction tank (111). Here, the iron salt (124) may contain Fe(III) and may contain ferric sulfate (Fe2(SO4)3). Alternatively, it may contain ferrous sulfate (FeSO4). In addition, it may contain ferric chloride (FeCl3) and ferrous chloride (FeCl2). Additionally, sulfuric acid may be introduced if necessary.

[0105] The amount of iron salt added may be 5.5 to 16.7% or 5 to 20% of the total organic carbon (TOC) contained in the mixed wastewater. For example, if the TOC of the mixed wastewater is 5,000 ppm, 279 to 838 ppm of Fe may be added.

[0106] Additionally, caustic soda (123) can be introduced from the chemical injection section (120) into the reaction tank (111). Caustic soda (123) can be introduced as NaOH to optimize the Fenton reaction. By introducing caustic soda (123), the acidity of the mixed waste liquid can be adjusted to a pH range of 2 to 4. By introducing caustic soda (123), the conversion of Fe(III) to Fe(II) is accelerated by the manganese (Mn(II)) ions generated during the mixing process of the mixed waste liquid, thereby accelerating the generation of OH radicals (hydroxyl radicals), which are powerful oxidizing agents, from hydrogen peroxide. For Fenton oxidation, the Fenton oxidation reaction can be induced even if ferric sulfate (Fe2(SO4)3) is used instead of ferrous chloride (FeCl2).

[0107] Through this, facility corrosion caused by ferrous chloride can be prevented, and at the same time, chemical unit costs can be reduced, providing advantages in terms of facility operation and maintenance. Additionally, by inducing a significant Fenton oxidation reaction with Mn(II), chelate chemicals are formed with copper in the wastewater. This removes all or most of the formaldehyde / tartaric acid that hinders copper coagulation and sedimentation, thereby optimizing the subsequent coagulation and sedimentation reactions and increasing the copper recovery rate.

[0108] In addition, by accelerating the Fenton oxidation reaction, the removal efficiency based on TOC (Total Organic Carbon) can be increased. For example, the removal efficiency can be increased from 40% to 70% compared to the case where permanganate waste liquid is not used.

[0109] Heat may be generated during the Fenton oxidation reaction in the reaction tank (111). For example, the heat may rise by about 10 to 30 degrees due to the Fenton oxidation reaction. At this time, the heat generated during the Fenton oxidation can be recovered through a heat exchanger. The heat exchanger (140) may include a plate / shell-and-tube type heat exchanger. Alternatively, it may include a plate heat exchanger or a shell-and-tube heat exchanger. The heat exchanger (140) can preheat raw water fed into the evaporator / concentrator (MVR / TVR) of another wastewater stream through heat exchange, or supply it to other heat sources required within the workplace, thereby improving energy savings and heat source self-sufficiency.

[0110] During the Fenton oxidation reaction in the reaction tank (111), the temperature of the mixed wastewater can be controlled to a level below a standard value. The temperature of the mixed wastewater may be 50 degrees or lower or 40 degrees or lower, and may be set by the test or the user. If the temperature of the reaction tank (111) is too high, for example, if the temperature of the reaction tank (111) exceeds 50 degrees, the self-decomposition reaction of hydrogen peroxide (132) occurs, decomposing into water and oxygen, making it difficult to generate OH radicals. By controlling the temperature of the mixed wastewater to a level below a standard value, the generation of OH radicals can be maximized, and thereby, the efficiency of removing difficult-to-decompose and toxic pollutants through the Fenton oxidation reaction can be optimized. To this end, the temperature of the mixed wastewater can be controlled to a level below a standard value. The temperature, pH, ORP, TOC, etc. of the mixed wastewater can be monitored in real time using a sensor, and the control unit can control the temperature of the mixed wastewater.

[0111] At this time, in order to control the temperature of the mixed wastewater, the supply of wastewater containing hydrogen peroxide (132) can be controlled. If the proportion of wastewater containing hydrogen peroxide (132) in the mixed wastewater is high, the concentration of hydrogen peroxide (132) in the mixed wastewater increases, which may generate a large amount of heat, and as a result, the self-decomposition reaction of hydrogen peroxide (132) may occur, making it difficult to generate OH radicals, so the supply of wastewater containing hydrogen peroxide (132) can be controlled. At this time, wastewater containing hydrogen peroxide (132) can be supplied and mixed into the mixed wastewater so that the concentration of hydrogen peroxide (132) is within 2% of the mixed wastewater. Wastewater other than that containing hydrogen peroxide (132) can be supplied to the reaction tank (111) in advance, and the supply amount of only wastewater containing hydrogen peroxide (132) can be controlled. Alternatively, the total waste liquid supply volume can be controlled by dividing the total waste liquid into a certain ratio.

[0112] Depending on the amount of waste liquid containing hydrogen peroxide (132), the process of performing Fenton oxidation and the process of exchanging heat can be performed multiple times. Even if all waste liquid containing hydrogen peroxide (132) is mixed, if the temperature of the mixed waste liquid resulting from Fenton oxidation is below a reference value, Fenton oxidation can be performed without repetition. However, if the mixing is done so that the proportion of waste liquid containing hydrogen peroxide (132) increases, the temperature of the mixed waste liquid resulting from Fenton oxidation may exceed the reference value. Therefore, Fenton oxidation can be performed by adjusting the input of waste liquid containing hydrogen peroxide (132) so that the temperature of the mixed waste liquid resulting from Fenton oxidation is below the reference value. Afterward, heat can be exchanged to lower the temperature of the mixed waste liquid, and additional waste liquid containing hydrogen peroxide (132) can be input to perform Fenton oxidation. Depending on the amount of waste liquid containing hydrogen peroxide (132), the process of performing Fenton oxidation and the process of exchanging heat can be repeated two or more times. In addition, the temperature of the mixed waste liquid can be measured to control the supply amount of waste liquid containing hydrogen peroxide (132) in real time so that the temperature of the mixed waste liquid is below a reference value.

[0113] After Fenton oxidation is performed in the Fenton oxidation unit (110), quicklime (125) is introduced from the chemical injection unit (120) into the reaction tank (111) so that heavy metals in the mixed waste liquid can be aggregated. Quicklime (125) is calcium hydroxide (Ca(OH)₂) and is called caustic lime, and has strong basicity in an aqueous solution. After Fenton oxidation is performed, quicklime (125) is introduced to adjust the acidity of the mixed waste liquid to a pH range of 9 to 11, thereby inducing an aggregation reaction for the removal of heavy metals.

[0114] The chemical injection unit (120) can inject iron salt, caustic soda, and quicklime into the Fenton oxidation unit (110) according to the process sequence. The chemical injection unit (120) can inject iron salt and caustic soda sequentially or simultaneously in the Fenton oxidation process, and subsequently inject quicklime in the heavy metal coagulation process. The chemical injection unit (120) can inject iron salt, caustic soda, and quicklime (121) into the reaction tank (111). In the mixed waste liquid within the Fenton oxidation unit (110), Fenton oxidation is performed by the iron salt (124) and caustic soda (123) injected from the chemical injection unit (120), and heavy metals can be coagulated by the quicklime (125) injected from the chemical injection unit (120).

[0115] After adding quicklime, the chemical injection unit (120) can add a separation chemical or a coagulant. Here, a polymer, which is a high-molecular-weight coagulant, can be added as the coagulant. Various coagulants other than polymers can be added. After adding quicklime (125), the mixed waste liquid moves to the coagulation tank (112), and a polymer can be added (122) to the coagulation tank (112). The polymer may include a high molecular weight water-soluble polymer and can play a role in separating fine particles by collecting them to form large flocs through sedimentation or flotation. Fine flocs can be generated first using quicklime, and large flocs can be generated second using polymer to coagulate heavy metals. The control unit can control the chemical injection of the chemical injection unit (120) by monitoring the temperature, pH, etc. of the reaction tank.

[0116] The mixed waste liquid into which the polymer is introduced is transferred to a sedimentation tank (113), and the mixed waste liquid can be separated into sedimenting sludge and supernatant water. The sludge can be transferred to a concentration tank (114) and concentrated. Afterward, water can be removed through a dewatering machine (115) to produce a dewatered cake. At this time, the copper content contained in the sludge after the dewatering process of the dewatering machine (115) may be 6 wt% or more based on the dry weight of the sludge after the dewatering process. The copper content of the sludge is 6 wt% or more based on the dry weight, making it a recyclable material. Through this, high-concentration copper sludge can be utilized as a resource. The sludge after the dewatering process may contain copper, iron, and quicklime.

[0117] It may include a sensor that senses the copper content in the sludge, and may include a resource recovery module that converts the sludge into a resource when the copper content in the sludge exceeds a certain standard. The resource recovery module analyzes the copper content in the sludge in real time, and if it exceeds the standard, it can automatically classify the sludge and convert it into a resource.

[0118] The supernatant can be separated from the sludge and transferred to the wastewater treatment unit (150). In the wastewater treatment unit (150), the supernatant can be biodegraded through biological treatment of residual organic matter and transferred to a discharge tank for discharge. When the supernatant is transferred to the wastewater treatment unit (150), its acidity can be adjusted to an acidity suitable for wastewater treatment. The supernatant can be reduced in molecular weight and become non-toxic through the Fenton oxidation reaction, thereby achieving a biodegradability level equivalent to methanol, which can increase the efficiency of the biological process operation.

[0119] The wastewater treatment unit (150) can perform activated carbon adsorption. The wastewater treatment unit (150) can remove residual organic matter through activated carbon adsorption along with biological treatment.

[0120] At least one waste liquid containing permanganate and at least one waste liquid containing hydrogen peroxide are mixed, and Fenton oxidation is performed by adding iron salt and caustic soda to the mixed waste liquid, and heavy metals are coagulated by adding quicklime, and by recovering and utilizing the heat generated from Fenton oxidation, the cost of oxidizing agents and handling risks can be reduced by not adding external hydrogen peroxide, and the cost of chemical input can be reduced by using ferric sulfate or ferrous sulfate. In addition, the Fenton reaction can be accelerated by utilizing manganese ions in the permanganate wastewater, thereby increasing the removal efficiency based on TOC (Total Organic Carbon). Furthermore, by removing formaldehyde and tartaric acid—which form chelate compounds with heavy metals among the TOC components in the wastewater—through wastewater mixing and the Fenton reaction, the heavy metal removal rate during the coagulation and sedimentation stage can be increased. Additionally, the treated water entering the biological process is converted into a low-molecular-weight and non-toxic state through the Fenton reaction, achieving a biodegradability level comparable to methanol, which can enhance the operational efficiency of the biological process. Moreover, by optimizing the amount of sludge generated, it is possible to achieve a copper (Cu) content of ≥6 wt% (based on dry weight) in the sludge, enabling its sale and resulting in resource recycling and increased revenue. Additionally, by utilizing the exothermic reaction generated during the Fenton reaction to preheat raw water input for evaporation and concentration or supply it to other heat sources within the facility, energy savings and improved heat source self-sufficiency can be achieved.

[0121] FIG. 8 is a flowchart of a wastewater treatment method according to one embodiment of the present invention, and FIGS. 9 to 12 are flowcharts of a wastewater treatment method according to an embodiment of the present invention. The detailed description of each step in FIGS. 8 to 12 corresponds to the detailed description of the wastewater treatment apparatus in FIGS. 1 to 4; therefore, the following descriptions of duplicates will be explained briefly.

[0122] For wastewater treatment of a wastewater treatment device comprising a reaction vessel in which wastewater is supplied and Fenton oxidation is performed, and a heat exchanger for recovering heat generated in said reaction vessel, the temperature of the reaction vessel is sensed in step S11, and the heat exchanger is controlled using the temperature of the reaction vessel in step S12.

[0123] After step S11, in step S21, the state of the reaction vessel is determined according to the temperature of the reaction vessel, and in step S22, the heat exchanger can be controlled according to the state of the reaction vessel.

[0124] Step S12 can be performed in steps S31 to S34 depending on the temperature of the reaction vessel. If the temperature of the reaction vessel is below a first reference value, the heat exchanger is controlled in step S31 so that the amount of heat recovered by the heat exchanger is less than or equal to the first value; if the temperature of the reaction vessel is above the first reference value but below the second reference value, the heat exchanger is controlled to a normal state in step S32; if the temperature of the reaction vessel is above the second reference value but below the third reference value, the amount of heat recovered by the heat exchanger is increased stepwise in step S33; and if the temperature of the reaction vessel is above the third reference value, at least a portion of the waste liquid stored in the reaction vessel can be transferred to an emergency collection tank in step S34.

[0125] Afterwards, diluted water can be injected into the emergency collection tank at step S41.

[0126] In addition, if the temperature of the reaction vessel is greater than or equal to the third reference value, the supply of waste liquid to the reaction vessel can be blocked in step S51.

[0130] FIGS. 13 to 17 are flowcharts of a wastewater treatment method in a wastewater treatment system according to an embodiment of the present invention. The detailed description of each step in FIGS. 13 to 17 corresponds to the detailed description of the process of the wastewater treatment system in FIGS. 5 to 7; therefore, the following descriptions will be brief if they are redundant.

[0131] To treat wastewater, a mixed waste solution may be produced in step S110 by mixing a waste solution containing permanganate and a waste solution containing hydrogen peroxide. Here, the waste solution to be mixed may include waste solution generated from the desmear process, waste solution generated from the electroplating process, and waste solution generated from the chemical plating process. The acidity of the mixed waste solution may be pH 3 or lower.

[0132] In step S120, Fenton oxidation can be performed by adding iron salt and caustic soda to the mixed waste liquid to produce treated water. Here, the amount of iron salt added may be 5 to 20% of the total organic carbon amount contained in the mixed waste liquid, and caustic soda may be added so that the acidity is in the range of pH 2 to 4.

[0133] After step S120, in step S130, quicklime can be added to the treated water to coagulate heavy metals. Here, quicklime can be added so that the acidity of the mixed wastewater is in the range of pH 9 to 11.

[0134] After step S120 and before step S130, the heat generated in step S120, which generates treated water in step S210, can be exchanged. Here, when generating treated water by performing Fenton oxidation, the temperature of the mixed waste liquid may be 50 degrees or lower.

[0135] In addition, depending on the amount of waste liquid containing hydrogen peroxide, step S120, which generates treated water in step S310, and step S210, which exchanges heat, can be repeated two or more times. Through this, the Fenton oxidation reaction can be optimized.

[0136] After step S130, after adding quicklime in step S410, a polymer may be added. Through this, the treated water is separated into supernatant and sludge, and the separated sludge undergoes a dewatering process. The copper content of the sludge after the dewatering process may be 6 wt% or more based on the dry weight of the sludge after the dewatering process. The sludge after the dewatering process may contain copper, iron, and quicklime. The supernatant may be discharged after biodegrading residual organic matter through biological treatment in step S510.

[0137] As described above, at least one waste liquid containing permanganate and at least one waste liquid containing hydrogen peroxide are mixed, and Fenton oxidation is performed by adding iron salt and caustic soda to the mixed waste liquid, and heavy metals are coagulated by adding quicklime, and by recovering and utilizing the heat generated from Fenton oxidation, the cost of the oxidizing agent and handling risk can be reduced by not adding external hydrogen peroxide, and the cost of adding chemicals can be reduced by using ferric sulfate or ferrous sulfate. In addition, the Fenton reaction can be accelerated by utilizing manganese ions in the permanganate wastewater, thereby increasing the removal efficiency based on TOC (Total Organic Carbon). Furthermore, by removing formaldehyde and tartaric acid—which form chelate compounds with heavy metals among the TOC components in the wastewater—through wastewater mixing and the Fenton reaction, the heavy metal removal rate during the coagulation and sedimentation stage can be increased. Additionally, the treated water entering the biological process is converted into a low-molecular-weight and non-toxic state through the Fenton reaction, achieving a biodegradability level comparable to methanol, which can enhance the operational efficiency of the biological process. Moreover, by optimizing the amount of sludge generated, it is possible to achieve a copper (Cu) content of ≥6 wt% (based on dry weight) in the sludge, enabling its sale and resulting in resource recycling and increased revenue. Additionally, by utilizing the exothermic reaction generated during the Fenton reaction to preheat raw water input for evaporation and concentration or supply it to other heat sources within the facility, energy savings and improved heat source self-sufficiency can be achieved.

[0139] Meanwhile, embodiments of the present invention can be implemented as computer-readable code on a computer-readable recording medium. A computer-readable recording medium includes all types of recording devices in which data that can be read by a computer system is stored.

[0140] Examples of computer-readable recording media include ROM, RAM, CD-ROM, magnetic tape, floppy disk, and optical data storage devices. Additionally, computer-readable recording media may be distributed across networked computer systems, allowing computer-readable code to be stored and executed in a distributed manner. Furthermore, functional programs, codes, and code segments for implementing the present invention can be easily inferred by programmers in the technical field to which the present invention belongs.

[0141] Although embodiments of the present invention have been described above with reference to the attached drawings, those skilled in the art will understand that the present invention may be implemented in other specific forms without changing its technical concept or essential features. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive.

Claims

Claim 1 An industrial wastewater treatment device comprising: a reaction tank receiving waste liquid and performing Fenton oxidation; a heat exchanger recovering heat generated in the reaction tank; a sensing unit sensing the temperature of the reaction tank; an emergency collection tank in which at least a portion of the waste liquid stored in the reaction tank is transferred when the temperature of the reaction tank is greater than or equal to a third reference value; and a control unit controlling the heat exchanger using the sensing value of the sensing unit, wherein the emergency collection tank includes a dilution water injector for injecting dilution water into the transferred waste liquid. Claim 2 An industrial wastewater treatment device according to claim 1, wherein the control unit determines the state of the reaction vessel according to the temperature of the reaction vessel and controls the heat exchanger according to the state of the reaction vessel. Claim 3 An industrial wastewater treatment device according to paragraph 2, wherein the control unit controls the heat exchanger so that the heat recovery amount of the heat exchanger becomes less than or equal to the first value when the temperature of the reaction tank is less than the first reference value, controls the heat exchanger to a normal state when the temperature of the reaction tank is greater than or equal to the first reference value or less than the second reference value, and gradually increases the heat recovery amount of the heat exchanger when the temperature of the reaction tank is greater than or equal to the second reference value. Claim 4 An industrial wastewater treatment device according to claim 1, wherein the sensing unit comprises: a first sensing unit for sensing the temperature of the reaction vessel; and a second sensing unit for sensing the temperature of the heat exchanger. Claim 5 An industrial wastewater treatment device according to claim 4, wherein the first sensing unit comprises: a first-1 sensing unit for sensing the temperature of the upper part of the reaction tank; a first-2 sensing unit for sensing the temperature of the central part of the reaction tank; and a first-3 sensing unit for sensing the temperature of the lower part of the reaction tank. Claim 6 An industrial wastewater treatment device according to claim 4, wherein the heat exchanger comprises an inlet through which a heat exchange medium flows in and an outlet through which the heat exchange medium flows out, and the second sensing unit comprises a second-1 sensing unit for sensing the temperature of the inlet of the heat exchanger; and a second-2 sensing unit for sensing the temperature of the outlet of the heat exchanger. Claim 7 An industrial wastewater treatment device according to claim 6, wherein the second sensing unit comprises: a second-3 sensing unit for sensing the pressure at the inlet of the heat exchanger; and a second-4 sensing unit for sensing the pressure at the outlet of the heat exchanger. Claim 8 delete Claim 9 An industrial wastewater treatment device according to claim 1, wherein the control unit cuts off the supply of waste liquid to the reaction tank and opens an emergency transfer line to transfer at least a portion of the waste liquid stored in the reaction tank to an emergency collection tank when the temperature of the reaction tank is above the third reference value. Claim 10 delete Claim 11 An industrial wastewater treatment device according to claim 1, wherein the sensing unit comprises a third sensing unit for measuring the temperature of the emergency water collection tank. Claim 12 An industrial wastewater treatment device according to claim 1, wherein the sensing unit comprises a fourth sensing unit for measuring the temperature of a heat load that receives heat recovered from the heat exchange unit. Claim 13 In Clause 12, the above heat load is an industrial wastewater treatment device including an evaporative concentrate source tank. Claim 14 An industrial wastewater treatment device according to claim 1, wherein the sensing unit comprises a fifth sensing unit that measures at least one of the total organic carbon amount, redox potential, and pH of the reaction tank. Claim 15 A method for treating industrial wastewater using an industrial wastewater treatment apparatus comprising a reaction vessel receiving wastewater and performing Fenton oxidation, and a heat exchanger for recovering heat generated in the reaction vessel, comprising: a step of sensing the temperature of the reaction vessel; and a step of controlling the heat exchanger using the temperature of the reaction vessel, wherein the step of controlling the heat exchanger comprises: a step of controlling the heat exchanger such that the amount of heat recovered by the heat exchanger becomes less than or equal to the first value when the temperature of the reaction vessel is less than or equal to the first reference value; a step of controlling the heat exchanger to a normal state when the temperature of the reaction vessel is greater than or equal to the first reference value or less than the second reference value; a step of gradually increasing the amount of heat recovered by the heat exchanger when the temperature of the reaction vessel is greater than or equal to the second reference value or less than the third reference value; a step of transferring at least a portion of the wastewater stored in the reaction vessel to an emergency collection tank when the temperature of the reaction vessel is greater than or equal to the third reference value; and a step of introducing dilution water into the emergency collection tank. Claim 16 An industrial wastewater treatment method according to claim 15, comprising the step of determining the state of the reaction vessel according to the temperature of the reaction vessel, and controlling the heat exchanger according to the state of the reaction vessel. Claim 17 delete Claim 18 delete Claim 19 An industrial wastewater treatment method according to claim 15, comprising the step of blocking the supply of waste liquid to the reaction tank when the temperature of the reaction tank is greater than or equal to the third reference value.

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