Method and system for removing azole compounds from wastewater

Abstract

The present disclosure provides a method for reducing or removing azole compounds from wastewater such as semiconductor wastewater. This method includes adding a solution containing transition metal (II) ions to the wastewater containing an azole compound, and forming a transition metal-azole complex in the wastewater with the transition metal (II) ions and the azole compound in the wastewater. The transition metal ions are Cu 2+ ions and / or Zn 2+ ions.

Description

Technical Field

[0001] Related Applications This application claims priority and the benefit thereof to U.S. Provisional Patent Application No. 63 / 391,914, filed Jul. 25, 2022, which is incorporated herein by reference in its entirety.

[0002] Field This specification relates to methods and systems for reducing or removing azole compounds from wastewater.

Background Art

[0003] Background The following paragraphs do not admit that what is discussed therein is prior art or part of the knowledge of those skilled in the art.

[0004] Azole is a class of five-membered heterocyclic compounds having a nitrogen atom and at least one other heteroatom as part of the ring. Some azole compounds are used in the manufacturing process of semiconductor devices as corrosion prevention compounds for copper. The wastewater generated from such manufacturing processes can be treated using oxidizing agents such as ozone, hydrogen peroxide, or by irradiation with ultraviolet light to reduce or remove azole compounds.

[0005] U.S. Patent No. 8,801,937 discloses a process for removing azole-based corrosion prevention compounds of copper from semiconductor wastewater. This process involves reacting ferrous ions with azole-type compounds at pH 4 - 8 to form insoluble iron-azole complexes, which are removed by flocculation / solid-liquid separation. Subsequently, the water separated by solid-liquid separation is oxidized in an ozone-based process to obtain treated water with a triazole concentration of 1.5 mg / L or less in terms of TOC.

[0006] The ’937 patent shows that water containing 1,2,4-triazole at a concentration of 300 mg / L in terms of TOC can be treated with 2000 mg / L of ferrous sulfate and subsequently with a polymer flocculant to produce treated water having a TOC concentration of 54 mg / L.

[0007] The ’937 patent also shows that water containing 1,2,4-triazole at a concentration of 180 mg / L can be treated with 5000 mg / L of ferrous sulfate and subsequently with a polymer flocculant to produce filtered water having a triazole concentration of 90 mg / L. When the filtered water is oxidized using an ozone-based process, treated water with a triazole concentration of less than 1.5 mg / L is obtained.

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Summary of the Invention

[0009] Preamble The following preamble is intended to introduce this specification to the reader and does not define any invention. One or more inventions may reside in combinations or sub-combinations of apparatus elements or method steps described below or elsewhere in this specification. The inventors do not disclaim or abandon any rights to any invention disclosed herein, merely by not claiming such other inventions in the claims.

[0010] The effluent discharged by a wastewater treatment plant can be adjusted within the limits of parameters such as total nitrogen (TN). Total nitrogen can be reduced by treating the influent wastewater in a process that includes nitrification. Nitrification is a biological process that converts ammonia to nitrite and nitrite to nitrate. Azole compounds can potentially inhibit the biological conversion from ammonia to nitrate. In some situations, wastewater containing 1 mg / L of 1,2,4-triazole can even be sufficiently harmful to the nitrification treatment process, and the wastewater generated by the nitrification process may not be able to meet the local discharge limits. In some situations, it may be desirable to reduce the concentration of soluble azole compounds in the wastewater to be nitrified to less than 1 mg / L, for example, less than 0.5 mg / L or less than 0.1 mg / L. The azole-containing wastewater generated by industrial processes such as semiconductor manufacturing can be diluted with azole-free wastewater before the nitrification process to provide the desired concentration, but instead or additionally, it may be desirable to reduce the concentration of soluble azole compounds in the wastewater generated by the industrial process.

[0011] In some aspects of the present disclosure, the method and system can treat wastewater without using an oxidation step or an oxidation unit to reduce or remove soluble azole compounds. In other aspects of the present disclosure, the method and system may treat the wastewater using an oxidation step or an oxidation unit to reduce or remove soluble azole compounds.

[0012] In one aspect, the present disclosure provides a method for reducing or removing azole-based compounds from wastewater such as semiconductor wastewater. The method includes adding a solution containing transition metal (II) ions to the wastewater containing azole compounds and forming a transition metal-azole complex in the wastewater with the transition metal (II) ions and azole compounds in the wastewater. The transition metal ions can be Cu 2+ ions, Zn 2+ ions, and / or Mn 2+ ions.

[0013] Transition metal-azole complexes can be soluble or insoluble under certain wastewater conditions. For example, a transition metal-azole complex can be soluble at a certain pH and may be insoluble at a different pH. The insoluble transition metal-azole complex can be removed by processes such as coagulation, flocculation, and / or solid-liquid separation processes, and the azole-reduced wastewater may be further treated in biological treatment including nitrification. Alternatively, wastewater containing a transition metal-azole complex may be transferred to a biological treatment reactor that performs nitrification as long as the reactor conditions render the transition metal-azole complex insoluble.

[0014] In another aspect, the present disclosure provides a wastewater treatment system comprising a source of wastewater containing an azole compound, a reactor in fluid communication with the source of the wastewater, a source of a solution containing transition metal (II) ions in fluid communication with the reactor, and a solid-liquid separator in fluid communication with the reactor. The solution containing transition metal (II) ions may contain Cu 2+ ions, Zn 2+ ions, and / or Mn 2+ ions.

[0015] The system may also include a biological treatment unit in fluid communication with a liquid outlet from the reactor or the solid-liquid separator. The biological treatment unit nitrifies the received wastewater. The system may include a source of a pH adjustment solution, such as a base, in fluid communication with the fluid flow between the reactor, the biological treatment unit, or both.

[0016] In one particular example according to the present disclosure, the method involves Cu 2+ ions, Zn 2+ ions, and / or Mn 2+Adding a solution containing ions to semiconductor wastewater containing an azole compound, maintaining the wastewater at a pH between 4 and 9, forming copper-azole, zinc-azole, and / or manganese-azole complexes in the wastewater with the copper ions, zinc ions, and / or manganese ions and the azole compound in the wastewater, removing at least some of the copper-azole, zinc-azole, and / or manganese-azole complexes from the wastewater to produce azole-reduced wastewater, and treating the azole-reduced wastewater in a biological treatment process including nitrification.

[0017] In another specific example according to the present disclosure, the method includes Cu 2+ ions, Zn 2+ ions, and / or Mn 2+ Adding a solution containing ions to semiconductor wastewater containing an azole compound, forming copper-azole, zinc-azole, and / or manganese-azole complexes in the wastewater with the copper, zinc, and / or manganese ions and the azole compound in the wastewater, and treating the wastewater in a biological treatment process including nitrification, where the biological treatment process is maintained at a pH between 4 and 9.

[0018] In another aspect, the present disclosure provides a method including adding a solution containing Cu 2+ ions to semiconductor wastewater containing a triazole compound such as 1,2,4-triazole, forming a copper-triazole complex in the wastewater while maintaining the pH of the solution above 4 with the copper ions and the triazole compound in the wastewater, and producing treated wastewater. The method optionally includes removing at least a portion of the insoluble copper-triazole complex to produce triazole-reduced wastewater, and optionally discharging the treated wastewater or the triazole-reduced wastewater to a downstream biological treatment including nitrification.

[0019] In yet another aspect, the present disclosure provides a reactor including at least one liquid inlet and at least one liquid outlet, a source of semiconductor wastewater containing a triazole compound such as 1,2,4-triazole in fluid communication with the reactor, and Cu in fluid communication with the reactor 2+Provide a wastewater treatment system including a source of a solution containing ions and a source of a pH adjustment solution, such as a base, in fluid communication with the reactor. The source of the pH adjustment solution is for maintaining the pH of the wastewater above 4. The system can optionally include a solid-liquid separator in fluid communication with the liquid outlet of the reactor.

[0020] In certain examples according to any of the methods and systems disclosed herein, the azole-containing wastewater may be semiconductor wastewater, and the solution containing transition metal (II) ions may be a semiconductor wastewater containing Cu 2+ ions, or may contain such wastewater. The method according to the present disclosure may include combining a sufficient amount of copper ion-containing wastewater to react with substantially all of the azole compounds in other semiconductor wastewater.

[0021] In another aspect, the present disclosure provides a method for estimating or quantifying the concentration of azole present in a solution. This method includes supplying a sample of the solution, titrating the solution using a Cu 2+ solution as the titrant, performing a colorimetric analysis of the sample, and measuring the concentration of azole based on the titration volume of the titrant, the concentration of the titrant, and the volume of the sample to determine the point when the titration end point is reached. The Cu 2+ solution can be a CuSO4 solution or a CuCl2 solution.

[0022] Embodiments of the present disclosure will be described below by way of example only with reference to the accompanying drawings.

Brief Description of the Drawings

[0023]

Figure 1

Modes for Carrying Out the Invention

[0024] Detailed Description Generally, the present disclosure provides a method for reducing or removing azole compounds from wastewater. This method includes adding a solution containing transition metal (II) ions to the wastewater containing azole compounds and forming a transition metal-azole complex in the wastewater with the transition metal (II) ions and azole compounds in the wastewater. The method according to the present disclosure can eliminate the oxidation of azole compounds by treatment with ozone and / or hydrogen peroxide, etc., as part of the process for reducing or removing azole compounds from wastewater. For example, the method according to the present disclosure may lack an oxidation treatment step upstream of the nitrification treatment.

[0025] The transition metal should be understood to refer to any element in the d-block of the periodic table in Groups 3-12 of the periodic table. The transition metal (II) ion should be understood to refer to any transition metal ion in the +2 oxidation state.

[0026] The transition metal (II) ion is Cu 2+ ions, Zn 2+ ions, Fe 2+ ions, Cr 2+ ions, Co 2+ ions, Mn 2+ ions, Ni 2+ ions, or any combination thereof. In a specific example, the transition metal (II) ion contains Cu 2+ , Zn 2+ , and / or Mn 2+ ions. The copper ions can be provided in a copper sulfate solution or a copper chloride solution. The copper ions can be provided in copper ion-containing semiconductor wastewater. The copper ion-containing semiconductor wastewater can be, for example, a copper sulfate solution generated from the sulfuric acid-based regeneration of an ion exchange resin used to remove copper ions from a solution. The method may include adding a sufficient amount of solution to provide a stoichiometric ratio of 1 to 5 times, for example, 1 to 3 times, of transition metal (II) ions such as copper ions to the azole compound.

[0027] The azole compound may be imidazole, pyrazole, oxazole, isoxazole, thiazole, isothiazole, selenazole, 1,2,3-triazole, 1,2,4-triazole, 1,2,5-oxadiazole, 1,3,4-oxadiazole, 1,2,3-thiadiazole, 1,2,4-thiadiazole, 1,3,4-thiadiazole, tetrazole, 1,2,3,4-thiatriazole, its derivative, its amine salt, or its metal salt.

[0028] Examples of the azole derivative include a compound having a condensed ring of an azole ring and a benzene ring, such as indazole, benzimidazole, benzotriazole, and benzothiazole, and its derivatives, such as alkylbenzotriazole (e.g., benzotriazole, o-tolyltriazole, m-tolyltriazole, p-tolyltriazole, 5-ethylbenzotriazole, 5-n-propylbenzotriazole, 5-isobutylbenzotriazole, and 4-methylbenzotriazole), alkoxybenzotriazole (e.g., 5-methoxybenzotriazole), alkylaminobenzotriazole, alkylaminosulfonylbenzotriazole, mercaptobenzotriazole, hydroxybenzotriazole, nitrobenzotriazole (e.g., 4-nitrobenzotriazole), halobenzotriazole (e.g., 5-chlorobenzotriazole), hydroxyalkylbenzotriazole, hydrobenzotriazole, aminobenzotriazole, (substituted aminomethyl)-tolyltriazole, carboxybenzotriazole, N-alkylbenzotriazole, bisbenzotriazole, naphthotriazole, mercaptobenzothiazole, aminobenzothiazole, its amine salt, and its metal salt.

[0029] In some examples, the azole compound contains an N-H functional group.

[0030] In certain examples, the azole compound can be a triazole compound or a pyrazole compound, such as 1,2,4-triazole, 3-amino-1,2,4-triazole, 5-methyl-benzotriazole, benzotriazole, pyrazole, or any combination thereof.

[0031] The wastewater can be semiconductor wastewater such as semiconductor wastewater having a total azole concentration of up to 450 mg / L. The semiconductor wastewater can contain 1,2,4-triazole at a concentration of up to 200 mg / L, such as a concentration of 5 - 20 mg / L, benzotriazole at a concentration of up to 80 mg / L, such as a concentration of 10 - 30 mg / L, 5-methylbenzotriazole at a concentration of up to 80 mg / L, such as a concentration of 5 - 20 mg / L, pyrazole at a concentration of up to 80 mg / L, such as a concentration of 0.1 mg / L or less, or any combination thereof.

[0032] Without wishing to be bound by theory, the inventors of the present disclosure believe that copper(II) ions preferentially reduce or remove azole compounds having three nitrogen atoms in the aromatic ring, such as triazole compounds, rather than azole compounds having two nitrogen atoms in the aromatic ring, such as pyrazole. The priority order of reactivity is considered to be 1,2,4-triazole > pyrazole > imidazole.

[0033] The transition metal-azole complex may be insoluble in the wastewater. When the transition metal-azole complex is insoluble in the wastewater, the method may also include removing at least a portion of the insoluble transition metal-azole complex to produce azole-reduced wastewater. Removal of at least a portion of the insoluble transition metal-azole complex can be carried out by filtering the wastewater to remove at least a portion of the insoluble complex, or by adding a coagulant such as ferric sulfate, ferric chloride, or ferrous sulfate, and / or a flocculant such as a polymer flocculant, and optionally clarifying the flocculated and / or coagulated wastewater.

[0034] Before removing at least a portion of the insoluble transition metal-azole complex, the method may also include adding to the wastewater a pH adjuster, such as a base, in an amount sufficient to provide a pH greater than 4, such as about pH 6. For example, the transition metal-azole complex may be a Cu 2+ -1,2,4-triazole complex, which is soluble in water at a pH less than 4 but insoluble at a pH greater than 4.

[0035] Wastewater containing 1,2,4-triazole and treated with copper sulfate may further be treated with a base such as sodium hydroxide to provide wastewater having a pH greater than 4, such as about pH 6. Such wastewater contains an insoluble copper(II)-1,2,4-triazole complex, and the method may include removing at least a portion of the insoluble copper(II)-1,2,4-triazole complex by filtering the wastewater, by adding a flocculant, a coagulant, or both, and optionally clarifying the flocculated and / or coagulated wastewater, or combinations thereof.

[0036] Wastewater with a reduced amount of azole compound can be treated in a biological treatment including nitrification. As described above, the method according to the present disclosure lacks an oxidation treatment step upstream of the nitrification treatment.

[0037] When the transition metal - azole complex is insoluble under biological treatment conditions, the method according to the present disclosure may include treating the wastewater in biological treatment including nitrification without first removing at least a portion of the insoluble transition metal - azole complex to produce azole - reduced wastewater. For example, wastewater containing 1,2,4 - triazole and treated with copper sulfate may be further treated with a base such as sodium hydroxide to provide wastewater with a pH above 4, such as about pH 6. The resulting copper(II) - 1,2,4 - triazole complex is insoluble at that pH, and an exemplary method includes treating the wastewater in biological treatment including nitrification. The insoluble copper(II) - 1,2,4 - triazole complex can be removed from the wastewater in a treatment process downstream of the biological treatment process. In some examples, the wastewater treated with copper(II) ions is not oxidized prior to nitrification treatment.

[0038] In another aspect, the present disclosure provides a wastewater treatment system including a source of wastewater containing an azole compound, a reactor in fluid communication with the source of the wastewater, and a source of a solution containing transition metal(II) ions in fluid communication with the reactor. The system may also include a solid - liquid separator in fluid communication with the reactor.

[0039] The solution containing transition metal(II) ions may include Cu 2+ ions, Zn 2+ ions, Fe 2+ ions, Cr 2+ ions, Co 2+ ions, Mn 2+ ions, Ni 2+ ions, or any combination thereof. In a particular example, the solution includes Cu 2+ ions, Zn 2+ ions, and / or Mn 2+ ions. The solution can be a copper sulfate solution or a copper chloride solution. The solution can be, or include, copper - ion - containing semiconductor wastewater such as a copper sulfate solution produced by regenerating an ion - exchange resin used to remove copper ions from the solution.

[0040] The wastewater treatment system may also include a source of a pH adjustment solution, such as a base, in fluid communication with the reactor. The system may include a pH monitor and a controller that maintains the pH of the wastewater above 4, for example, at about pH 6. Alternatively, the system may add the pH adjustment solution based on the molar amount of azole compounds known to be in the influent wastewater solution.

[0041] The solid-liquid separator may include a filter, such as a filter having a pore size of 0.1 micron or less, such as a filter having a membrane with an average pore size of about 0.025 μm, or a source of flocculant and / or coagulant, and optionally a clarifying agent.

[0042] The wastewater treatment system may also include a biological treatment unit in fluid communication with the liquid outlet from the reactor or the solid-liquid separator. The biological treatment unit may receive the azole-reduced wastewater from the solid-liquid separator or the wastewater having the insoluble transition metal-azole complex. The biological treatment unit nitrifies the received wastewater. Nitrification can be carried out in a membrane aeration bioreactor. The system may lack an oxidation unit, such as a treatment unit including an ozone injector, that removes azole compounds upstream of the biological treatment unit.

[0043] The wastewater treatment system can receive wastewater from a semiconductor manufacturing plant. The wastewater treatment system can receive copper ion-containing wastewater from a semiconductor manufacturing plant.

[0044] In another aspect, the present disclosure provides a method that includes preparing a sample of a solution, titrating the solution using a Cu 2+ solution as a titrant, performing a colorimetric analysis of the sample, and determining when the titration endpoint has been reached. The Cu 2+ solution can be a CuSO4 solution or a CuCl2 solution.

[0045] This method can be used to estimate or quantify the concentration of azole present in a solution, in which case it involves measuring the concentration of azole based on the volume of the titrant, the concentration of the titrant, and the volume of the sample.

[0046] The sample may be a sample of wastewater, such as semiconductor wastewater, such as a sample of semiconductor manufacturing wastewater. Examples of semiconductor wastewater have been described above. Estimating the concentration of azole present in the solution may be used to determine how many moles of transition metal (II) ions should be added in a wastewater treatment method such as those discussed above to produce azole-reduced wastewater.

[0047] When the sample is a sample of semiconductor wastewater, Cu used as the titrant 2+ The solution may be copper ion-containing semiconductor wastewater. The volume ratio of (titrant required to reach the titration endpoint: sample) can provide the volume ratio of (copper ion-containing semiconductor wastewater: semiconductor wastewater) that can be used to produce azole-reduced wastewater in the wastewater treatment method described above.

[0048] In some examples, at least 60 mol%, such as at least 70 mol%, at least 80 mol%, or at least 90 mol% of the azole in the sample is an azole-based compound having three nitrogen atoms in the aromatic ring, such as a triazole compound. In some examples, less than 10 mol%, such as less than 5 mol% or less than 1 mol% of the azole in the sample is an azole-based compound having two nitrogen atoms in the aromatic ring, such as a pyrazole compound.

[0049] Colorimetric analysis of a sample to be titrated can be carried out by using a direct or indirect method for detecting copper in order to determine the point at which the titration end point is reached. The direct detection method may include visual detection of copper sulfate or colorimetric detection at a wavelength of 750-900 nm. Indirect detection methods may include the bicinchoninate or bathocuproine method for quantifying dissolved copper (II) in the titration sample. The indirect detection method can be carried out using an EZ1000 series on-line colorimetric copper analyzer such as the EZ1010 or EZ1011 analyzer from HACH.

[0050] In other embodiments, the titration is the above-described Cu 2+ solution replaced with Zn 2+ solution or Mn 2+ solution. The analysis of the titration sample for detecting Zn 2+ or Mn 2+ at the point when the titration end point is reached may include an indirect detection method. The indirect detection method for Zn 2+ can be carried out using an EZ1040 Zn(II) analyzer from HACH that uses a 2-carboxy-2’ hydroxy-5’ sulfohormazylbenzene indicator, usually called zircon, in the ZincoVer(R) method for determining zinc concentration. The indirect detection method for Mn 2+ can be carried out using an EZ1025 Mn(II) analyzer from HACH that uses the formaldehyde oxime method for determining manganese concentration.

[0051] An exemplary wastewater treatment system is shown in FIG. 1. The system (100) includes a reactor (110) having an inlet for receiving wastewater (112) such as semiconductor wastewater. The wastewater (112) contains an azole compound. The reactor (110) also includes an inlet for receiving a solution (114) containing transition metal (II) ions. The solution (114) may be copper-containing semiconductor wastewater containing Cu 2+ ions. The reactor (110) includes an inlet for receiving a pH adjustment solution (116).

[0052] The reactor (110) outputs a process stream (118) having a transition metal - azole complex, which is received by a solid - liquid separator (120). The system may include a source of flocculant and / or coagulant (not shown). The solid - liquid separator (120) produces azole - reduced wastewater (122) and an azole - concentrated wastewater product (124).

[0053] The azole - reduced wastewater (122) is received by a biological treatment unit (126) that nitrifies the received wastewater. The biological treatment unit (126) outputs nitrogen - reduced wastewater (128).

Example

[0054] [Example 1] Deionized water was spiked with 1,2,4 - triazole, pyrazole, benzotriazole, and 5 - methylbenzotriazole to produce a solution containing 180 mg / L of 1,2,4 - triazole, 60 mg / L of pyrazole, 60 mg / L of benzotriazole, and 60 mg / L of 5 - methylbenzotriazole. While maintaining the pH at 6.0, the solution was treated with copper sulfate solutions at different concentrations (103.7, 207.4, 414.7, 829.4, 1037.0, and 1244.4 mg / L). The resulting insoluble copper - azole complexes were removed by filtration through a 0.025 μm membrane. The filtrate was tested for the amount of remaining azole compounds and TOC as a surrogate for the remaining copper. The results are shown in Table 1.

[0055]

Table 1

[0056] Furthermore, the filtrate treated with 1037 mg / L of copper sulfate was tested for the specific azoles used in the synthetic wastewater. The compounds (mg / L) contained in the effluent are as follows: 0.22 mg / L of 1,2,4 - triazole, 0.38 mg / L of benzotriazole, 22 mg / L of pyrazole, 0.14 mg / L of 5 - methylbenzotriazole.

[0057] [Examples 2 and 3] Considering the positive results from the tests outlined above, synthetic wastewater was prepared to mimic semiconductor wastewater. The synthetic wastewater had the characteristics shown in Table 2.

[0058]

Table 2

[0059] [Example 2] A particular synthetic wastewater had a pH of 6.5, a TDS of 5,650 mg / L, a total COD of 772 mg / L, an ammonium-N concentration of 767 mg-N / L, a 1,2,4-triazole concentration of 177 mg / L, a benzotriazole concentration of 60 mg / L, a 5-methylbenzotriazole concentration of 64 mg / L, and a pyrazole concentration of 62 mg / L.

[0060] This synthetic wastewater was treated with copper sulfate solutions at different concentrations (414.7, 829.4, 1037.0, and 1244.4 mg / L) while maintaining the pH at 6.0. The resulting insoluble copper-azole complexes were removed by filtration through a 0.025 μm membrane. The filtrate was tested for the amount of remaining azole compounds and TOC as a surrogate for the remaining copper. The results are shown in Table 3.

[0061]

Table 3

[0062] Furthermore, the filtrate was tested for the specific azoles used in the synthetic wastewater. The compounds (mg / L) contained in the effluent are shown in Table 4.

[0063]

Table 4

[0064] [Example 3] Another specific synthetic wastewater had a pH of 6.0, a concentration of 1,2,4-triazole of 140 mg / L, a concentration of benzotriazole of 54 mg / L, a concentration of 5-methylbenzotriazole of 58 mg / L, and a concentration of pyrazole of 53 mg / L.

[0065] This synthetic wastewater was treated with a 1037.0 mg / L copper sulfate solution under a reaction time of 5 - 20 minutes while maintaining the pH at 6.0. The resulting insoluble copper-azole complex was removed by filtration through a 0.025 μm membrane. The filtrate was tested for TOC and residual copper, and the results are shown in Table 5.

[0066]

Table 5

[0067] The filtrate was also tested for the specific azoles used in the synthetic wastewater. The compounds (mg / L) contained in the effluent are shown in Table 6.

[0068]

Table 6

[0069] In the foregoing description, for purposes of explanation, numerous details are set forth in order to provide a thorough understanding of the embodiments. However, it will be apparent to those skilled in the art that these specific details are not required. Accordingly, the described embodiments are merely exemplary of the application of the described examples, and numerous modifications and variations are possible in light of the above teachings.

[0070] The above description provides examples, so those skilled in the art will understand that modifications and variations can be made to specific examples. Accordingly, the claims should not be limited by the specific examples described herein, but should be construed as a whole to be consistent with this specification.

Claims

1. adding a solution containing transition metal (II) ions to the wastewater containing an azole compound, and forming a transition metal-azole complex in the wastewater between the transition metal (II) ions and the azole compound in the wastewater.

2. wherein the transition metal (II) ion is Cu ２＋ ion, Zn ２＋ ion, Fe ２＋ ion, Cr ２＋ ion, Co ２＋ ion, Mn ２＋ ion, Ni ２＋ ion, or any combination thereof, the method according to claim 1.

3. The transition metal (II) ion is Cu ２＋ ion, and the solution containing Cu ２＋ is a copper sulfate solution or a copper chloride solution, or contains copper ion-containing semiconductor wastewater. The method according to claim 2

4. Cu in an amount sufficient to provide a stoichiometric ratio of copper ions to azole compound of from 1 to 5 times, for example, from 1 to 3 times ２＋ The method according to claim 2 or 3, comprising adding said solution containing ions

5. The method according to any one of claims 1 to 4, wherein the azole compound is a triazole compound or a pyrazole compound, such as 1,2,4-triazole, 3-amino-1,2,4-triazole, 5-methylbenzotriazole, benzotriazole, pyrazole, or any combination thereof.

6. The method according to claim 5, wherein the wastewater is semiconductor wastewater having a total azole concentration of up to, for example, 450 mg / L, such as 1,2,4-triazole at a concentration of up to 200 mg / L, for example, at a concentration of 5 to 20 mg / L, benzotriazole at a concentration of up to 80 mg / L, for example, at a concentration of 10 to 30 mg / L, 5-methylbenzotriazole at a concentration of up to 80 mg / L, for example, at a concentration of 5 to 20 mg / L, pyrazole at a concentration of up to 80 mg / L, for example, at a concentration of 0.1 mg / L or less, or any combination thereof.

7. The method according to any one of claims 1 to 6, wherein the transition metal-azole complex is insoluble in the wastewater, and the method further comprises removing at least a part of the insoluble transition metal-azole complex to produce azole-reduced wastewater.

8. Removing at least a part of the insoluble transition metal-azole complex comprises filtering the wastewater to remove at least a part of the insoluble complex, or adding a coagulant such as ferric sulfate, ferric chloride, or ferrous sulfate, and / or a flocculant such as a polymer flocculant, and optionally clarifying the wastewater by flocculation and / or coagulation The method according to claim 7.

9. The method according to claim 7 or 8, further comprising adding to the wastewater an amount of base sufficient to provide a pH greater than 4, such as about pH 6, before removing at least a part of the insoluble transition metal-azole complex.

10. The method according to any one of claims 7 to 9, further comprising treating the azole-reduced wastewater in a biological treatment including nitrification, without optionally subjecting the azole-reduced wastewater to an oxidation treatment.

11. The method according to any one of claims 1 to 6, further comprising treating the wastewater in a biological treatment including nitrification without oxidizing the optionally azole-reduced wastewater, wherein the transition metal-azole complex is insoluble under biological treatment conditions.

12. The method according to claim 11, wherein the biological treatment is at a pH greater than 4.

13. A source of wastewater containing an azole compound, A reactor in fluid communication with the source of the wastewater, A source of a solution containing transition metal (II) ions in fluid communication with the reactor, Optionally, a solid-liquid separator in fluid communication with the reactor A wastewater treatment system comprising.

14. The solution containing the transition metal (II) ions is Cu ２＋ ions, Zn ２＋ ions, Fe ２＋ ions, Cr ２＋ ions, Co ２＋ ions, Mn ２＋ ions, Ni ２＋ ions, or any combination thereof, the wastewater treatment system according to claim 13.

15. The wastewater treatment system according to claim 14, wherein the solution containing transition metal (II) ions is a copper sulfate solution or a copper chloride solution, or contains copper ion-containing semiconductor wastewater.

16. The wastewater treatment system according to any one of claims 13 to 15, further comprising a source of a pH adjustment solution such as a base in fluid communication with the reactor, wherein the source of the pH adjustment solution is for maintaining the pH of the wastewater above 4.

17. The solid-liquid separator is A filter, for example, a filter having a pore size of 0.1 micron or less, for example, a filter having a membrane with an average pore size of about 0.025 μm, or A source of a flocculant and / or a coagulant and optionally a clarifying agent The wastewater treatment system according to any one of claims 13 to 16, comprising.

18. The wastewater treatment system according to any one of claims 13 to 17, further comprising a biological treatment unit in fluid communication with a liquid outlet from the reactor or the solid-liquid separator, wherein the biological treatment unit nitrifies the received wastewater, and optionally, the wastewater treatment system lacks an oxidation unit upstream of the biological treatment unit.

19. The wastewater treatment system according to any one of claims 13 to 18, wherein the source of the wastewater is a semiconductor manufacturing plant.

20. Cu ２＋ Adding a solution containing ions, such as a solution containing Cu ions, to semiconductor wastewater containing a triazole compound, for example, 1,2,4-triazole, and Forming a copper-triazole complex in the wastewater between the copper ions and the triazole compound in the wastewater to produce treated wastewater while maintaining the solution at a pH greater than 4, Optionally, removing at least a portion of the insoluble copper-triazole complex to produce azole-reduced wastewater, Optionally, discharging the treated wastewater or the azole-reduced wastewater to a downstream biological treatment including nitrification A method comprising

21. The method according to claim 20, comprising adding an amount of the solution sufficient to provide a stoichiometric ratio of copper ions to triazole compound of from 1 to 5 times, such as from 1 to 3 times.

22. The method according to claim 20 or 21, wherein the treated wastewater or the triazole-reduced wastewater has a soluble triazole concentration of less than 1.0 mg / L.

23. Cu ２＋ The method according to any one of claims 20 to 22, wherein the solution containing ions contains copper ion-containing semiconductor wastewater.

24. The method according to any one of claims 20 to 23, comprising discharging the treated wastewater or the triazole-reduced wastewater without oxidative treatment to a downstream biological treatment including nitrification.

25. A reactor comprising at least one liquid inlet and at least one liquid outlet, A source of semiconductor wastewater containing a triazole compound, such as 1,2,4-triazole, in fluid communication with the reactor, A source of a solution containing Cu ions that is in fluid communication with the reactor ２＋ ions A source of a pH adjustment solution, such as a base, in fluid communication with the reactor for maintaining the pH of the wastewater above 4, Optionally, a solid-liquid separator in fluid communication with the liquid outlet of the reactor A wastewater treatment system comprising

26. The wastewater treatment system according to claim 25, wherein the solution contains Cu2+ ions, the solution is a copper sulfate solution or a copper chloride solution, or the solution contains copper ion-containing semiconductor wastewater.

27. The solid-liquid separator is A filter, such as a filter having a pore size of 0.1 micron or less, such as a filter having a membrane with an average pore size of about 0.025 μm, or A source of flocculant and / or coagulant and optionally clarifying agent The wastewater treatment system according to claim 25 or 26, comprising

28. Further comprising a biological treatment unit in fluid communication with the liquid outlet from the reactor or the liquid outlet from the solid-liquid separator, the biological treatment unit nitrifying the received wastewater, and optionally the wastewater treatment system lacking an oxidation unit upstream of the biological treatment unit. The wastewater treatment system according to any one of claims 25 to 27.

29. Supplying a sample of the solution, Use Cu as the titrant ２＋ Titrate the solution using the solution Performing colorimetric analysis of the sample to determine the point in time when the titration endpoint is reached, Optionally, calculating the concentration of azole based on the titration volume of the titrant, the concentration of the titrant, and the volume of the sample A method comprising

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