Method and system for treating ammonia-nitrogen-containing wastewater by using integrated circuit TMAH waste liquid

Abstract

The invention relates to a method and a system for treating ammonia-nitrogen-containing wastewater by using integrated circuit TMAH waste liquid, belongs to the technical field of wastewater treatment, and is used for solving at least one of the problems that an ammonia-nitrogen-containing wastewater treatment system in the prior art is high in energy consumption, easy to generate new waste liquid, not low-carbon and environment-friendly, incapable of realizing resource utilization of TMAH waste liquid and the like. According to the ammonia-nitrogen-containing wastewater treatment method, the TMAH waste liquid is subjected to resource utilization, the TMAH waste liquid is subjected to oxidation treatment to obtain the small-molecular organic matter, the small-molecular organic matter serves as a carbon raw material for treating the ammonia-nitrogen-containing wastewater, the ammonia-nitrogen-containing wastewater is treated through a biological method, the method is environmentally friendly and saves energy, and the wastewater treated through the method can meet the emission standard.

Description

Technical Field

[0001] The present invention relates to the technical field of waste liquid treatment, and in particular to a method and system for treating ammonia nitrogen-containing wastewater by utilizing integrated circuit TMAH waste liquid. Background Art

[0002] Tetramethylammonium hydroxide (TMAH) is widely used as a developer in industries such as integrated circuits, liquid crystal displays, and printed circuit boards. The TMAH wastewater discharged from the integrated circuit production process typically has a concentration of 2.38%, is highly alkaline, and is toxic. Currently, integrated circuit factories typically mix TMAH wastewater with organic wastewater and discharge it after biochemical treatment. Due to its toxicity, microorganisms are less effective in decomposing TMAH, and the TMAH contained in the tailwater increases environmental pollution and harms human health. TMAH wastewater is a nitrogen-containing organic substance, and recycling it for resource utilization can reduce environmental pollution.

[0003] CN111285547A discloses a method for treating developer waste liquid, which mainly consists of units such as pH adjustment, coagulation and sedimentation, concentration adjustment, anaerobic biochemical, ammonia stripping and acid absorption. Since TMAH is toxic, it is difficult for microorganisms to degrade it, so this solution cannot effectively degrade TMAH waste liquid. CN207904107U discloses a TMAH waste liquid treatment system, which includes an air flotation device, an iron-carbon microelectronic device, a Fenton oxidation device, a pH adjustment device, an A 2 Wastewater treatment is performed using treatment units such as O-MBR units. This process has too many treatment units, resulting in an overly complex system and high treatment costs. The iron-carbon microelectronic device also has a long reaction time and low treatment efficiency. None of the aforementioned technologies utilize TMAH wastewater as a resource.

[0004] Typically, the ammonia-nitrogen wastewater discharged from integrated circuit production processes contains NH3-N at concentrations of 300-2000 mg / L, a chemical oxygen demand (COD) of 100-300 mg / L, and a pH of 8-10. This volume typically accounts for 5-15% of the total factory wastewater, making it a relatively large volume. The current mainstream treatment technology involves heating the wastewater to 50°C and then using a single or two-stage stripping process. Within the stripping tower, the NH3-N in the water is precipitated and reacts with sulfuric acid to produce ammonium sulfate wastewater. This method removes approximately 90%-95% of the NH3-N in the water. The degraded wastewater is then mixed with organic wastewater from the factory for further NH3-N degradation using biological methods. However, this treatment method is energy-intensive and expensive, and is not environmentally friendly. Furthermore, the NH3-N in the wastewater is not truly removed, but rather transferred to form ammonium sulfate wastewater, which requires further treatment.

[0005] Therefore, in response to the above technical problems, there is an urgent need to develop a treatment system and method that can not only utilize TMAH waste liquid as a resource, but also treat ammonia-nitrogen wastewater discharged from the integrated circuit production process with high efficiency, simple system structure, no secondary pollution to the environment, low operating costs, and easy to promote and apply on a large scale in industrialization. Summary of the Invention

[0006] In view of the above analysis, the present invention aims to provide a method and system for treating ammonia-nitrogen wastewater using integrated circuit TMAH waste liquid, so as to solve at least one of the problems in the prior art of ammonia-nitrogen wastewater treatment system, namely, high energy consumption, generation of new waste liquid, lack of low-carbon and environmental protection, and inability to recycle TMAH waste liquid.

[0007] In a first aspect, the present invention provides a method for treating ammonia-nitrogen-containing wastewater using integrated circuit TMAH waste liquid, comprising the following steps:

[0008] Step S1: After the pH value of the TMAH waste liquid is adjusted for the first time, a portion of ammonia nitrogen-containing waste water and a reagent are added to perform a first homogenization treatment and a TMAH oxidation treatment in sequence to obtain an oxidized TMAH waste liquid;

[0009] Step S2: After filtering another portion of the ammonia nitrogen-containing wastewater, the oxidized TMAH wastewater is added thereto, and the mixture is subjected to a second homogenization treatment and a second pH adjustment treatment, to obtain pretreated ammonia nitrogen-containing wastewater;

[0010] Step S3: sequentially subjecting the pretreated ammonia nitrogen-containing wastewater to a first denitrification treatment, a first nitrification treatment, a second denitrification treatment, a second nitrification treatment, and a precipitation treatment, and separating the treated wastewater and sludge.

[0011] Furthermore, in step S1, an acid is used to adjust the pH value to 4-7.

[0012] Furthermore, in step S1, the reagent includes divalent iron, a chelating agent and persulfate.

[0013] Furthermore, the divalent iron includes one or more of ferrous sulfate, ferrous nitrate or ferrous chloride;

[0014] The complexing agent is one or more of ethylenediaminetetraacetic acid, N-N'-ethylenediaminedisuccinic acid, nitrilotriacetic acid, and citric acid;

[0015] The persulfate is peroxymonosulfate and / or peroxydisulfate.

[0016] Furthermore, the dosage of the divalent iron is 200-2000 mg / L, the dosage of the complexing agent is 1-30 mg / L, and the dosage of the persulfate is 500-5000 mg / L.

[0017] Furthermore, in step S1, the volume ratio of TMAH waste liquid to ammonia nitrogen-containing wastewater is 1:10 to 1:250.

[0018] Furthermore, the volume ratio of the TMAH waste liquid in step S1 to the ammonia nitrogen-containing wastewater in step S2 is 1:2 to 1:20.

[0019] Furthermore, in step S2, the pH value is adjusted to 7-7.5.

[0020] Furthermore, in step S3, the sludge is partially returned to the first denitrification treatment to enhance the denitrification treatment effect, and the remaining sludge is discharged for treatment.

[0021] Furthermore, in step S3, the first denitrification treatment, the first nitrification treatment, the second denitrification treatment, and the second nitrification treatment are sequentially performed in the first anoxic tank, the first aerobic tank, the second anoxic tank, and the second aerobic tank.

[0022] In a second aspect, the present invention provides a system for treating ammonia-nitrogen-containing wastewater using integrated circuit TMAH wastewater. The system includes a TMAH wastewater pretreatment unit and an ammonia-nitrogen-containing wastewater treatment unit. After being treated by the TMAH wastewater pretreatment unit, the TMAH wastewater enters the ammonia-nitrogen-containing wastewater treatment unit as a carbon raw material for treating ammonia-nitrogen-containing wastewater.

[0023] Furthermore, the TMAH waste liquid pretreatment unit includes a waste liquid tank, a first pH adjustment tank, a first homogenization tank and a reaction tank connected in sequence according to the process flow.

[0024] Furthermore, the ammonia nitrogen-containing wastewater treatment unit includes a raw water tank, a manganese sand filter, a second equalization tank, a second pH adjustment tank, a first anoxic tank, a first aerobic tank, a second anoxic tank, a second aerobic tank and a sedimentation tank connected in sequence according to the process flow.

[0025] Furthermore, the raw water tank is also connected to the first equalization tank, the reaction tank is also connected to the second equalization tank, and the sedimentation tank is also connected to the first anoxic tank.

[0026] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0027] (1) The method for treating ammonia nitrogen-containing wastewater of the present invention utilizes TMAH waste liquid as a resource, and oxidizes the TMAH waste liquid to obtain small molecular organic matter. The small molecular organic matter is used as a carbon raw material for treating ammonia nitrogen-containing wastewater. The ammonia nitrogen-containing wastewater is treated by a biological method, which is green, environmentally friendly, and energy-saving. After being treated by the method of the present invention, the wastewater can meet the emission standards.

[0028] (2) After adding Fe(II), a complexing agent, and persulfate, the present invention constructs two advanced oxidation systems, the complexing agent-Fe(II)-H2O2 and the Fe(II)-persulfate, in the reaction system. On the one hand, in the complexing agent-Fe(II)-H2O2 advanced oxidation system, electron transfer occurs between H2O2 and Fe(II) to generate hydroxyl radicals, while Fe(II) is oxidized to Fe(III). The complexing agent reacts with Fe(II) and Fe(III) to generate Fe(II)L and Fe(III)L, which can enhance the reaction of Fe(II) / Fe(III) with H2O2. Hydroxyl radicals have strong oxidizing properties and can break the molecular chains of organic matter. On the other hand, in the Fe(II)-persulfate advanced oxidation system, Fe(II) and Fe(III) can act as donors, activating persulfate through single electron transfer to generate sulfate radicals. Sulfate radicals have strong oxidizing properties and can break the molecular chains of organic matter. The intermediate products of TMAH oxidation are amine-type organic compounds such as trimethylamine, dimethylamine, and methylamine. Sulfate radicals have a greater oxidative effect on the NH bonds in amine groups than hydroxyl radicals. Therefore, hydroxyl radicals and sulfate radicals work synergistically, resulting in a better degradation effect on TMAH wastewater, which can reduce the dosage of complexing agents, Fe(II), persulfate, and other reagents. TMAH molecules are degraded into easily biodegradable small organic molecules through chain scission. These small organic molecules serve as carbon sources, and ammonia nitrogen as a nitrogen source. Under the action of anoxic and aerobic microorganisms, they undergo denitrification and nitrification, respectively, degrading ammonia nitrogen and organic matter in the wastewater. The treated wastewater's NH3-N, total nitrogen (TN), and COD levels meet emission standards.

[0029] (3) The system of the present invention saves equipment investment and operating costs, is simple to operate, is environmentally friendly, and is convenient for large-scale industrial promotion and application.

[0030] In the present invention, the above-mentioned technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of the present invention will be described in the following description, and some advantages will become apparent from the description or be learned through practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the contents particularly pointed out in the description and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The accompanying drawings are only for the purpose of illustrating particular embodiments and are not to be considered limiting of the present invention. Like reference symbols denote like parts throughout the drawings.

[0032] Figure 1 This is a process flow chart of treating ammonia-nitrogen-containing wastewater using integrated circuit TMAH wastewater in the present invention;

[0033] Figure 2 This is a graph showing the degradation rate of TMAH over time in Experimental Example 2 of the present invention. DETAILED DESCRIPTION

[0034] The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein the accompanying drawings constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not used to limit the scope of the present invention.

[0035] A specific embodiment of the present invention discloses a method for treating ammonia nitrogen-containing wastewater using integrated circuit TMAH waste liquid, comprising the following steps:

[0036] Step S1: After the pH value of the TMAH waste liquid is adjusted for the first time, a portion of ammonia nitrogen-containing waste water and a reagent are added to perform a first homogenization treatment and a TMAH oxidation treatment in sequence to obtain an oxidized TMAH waste liquid;

[0037] Step S2: After filtering another portion of the ammonia nitrogen-containing wastewater, the oxidized TMAH wastewater is added thereto, and the mixture is subjected to a second homogenization treatment and a second pH adjustment treatment, to obtain pretreated ammonia nitrogen-containing wastewater;

[0038] Step S3: sequentially subjecting the pretreated ammonia nitrogen-containing wastewater to a first denitrification treatment, a first nitrification treatment, a second denitrification treatment, a second nitrification treatment, and a precipitation treatment, and separating the treated wastewater and sludge.

[0039] Compared with the prior art, the method for treating ammonia nitrogen-containing wastewater of the present invention utilizes TMAH waste liquid as a resource, oxidizes the TMAH waste liquid to obtain small-molecule organic matter, and uses the small-molecule organic matter as a carbon raw material for treating ammonia nitrogen-containing wastewater. The biological method is used to treat ammonia nitrogen-containing wastewater, which is green, environmentally friendly, and energy-saving. After being treated by the method of the present invention, the wastewater can meet the emission standards.

[0040] Because ammonia water with a 1:1:5 ratio of NH3:H2O2:H2O is typically used in integrated circuit production processes to clean tiny particles from chip surfaces, the discharged ammonia nitrogen wastewater typically contains H2O2 at a concentration of 500-5000 mg / L. The present invention first adds a portion of the ammonia nitrogen-containing wastewater to TMAH wastewater. The H2O2 in the ammonia nitrogen-containing wastewater forms an advanced oxidation system with a reagent, generating hydroxyl radicals and sulfate radicals. These two free radicals have a synergistic effect, efficiently degrading TMAH molecules into easily biodegradable small-molecule organic matter, thereby reducing the dosage of the reagent.

[0041] Specifically, in step S1, an acid is used to adjust the pH value to 4 to 7. At a pH value within the above range, the advanced oxidation system has high reaction efficiency and good TMAH degradation effect.

[0042] Preferably, the acid is one or more of hydrochloric acid, sulfuric acid or nitric acid.

[0043] Specifically, in step S1, the reagent includes divalent iron (Fe(II)), a chelating agent and persulfate.

[0044] Preferably, the divalent iron (Fe(II)) includes one or more of ferrous sulfate, ferrous nitrate or ferrous chloride;

[0045] The complexing agent is one or more of ethylenediaminetetraacetic acid (EDTA), N-N'-ethylenediaminedisuccinic acid (EDDS), nitrilotriacetic acid (NTA), and citric acid;

[0046] The persulfate is peroxymonosulfate (PMS) and / or peroxydisulfate (PDS).

[0047] It should be noted that after adding Fe(II), a complexing agent, and a persulfate, the present invention constructs two advanced oxidation systems, a complexing agent-Fe(II)-H2O2 and a Fe(II)-persulfate, in the reaction system. On the one hand, in the complexing agent-Fe(II)-H2O2 advanced oxidation system, electron transfer occurs between H2O2 and Fe(II) to generate hydroxyl radicals, while Fe(II) is oxidized to Fe(III). The complexing agent, Fe(II), and Fe(III) generate Fe(II)L and Fe(III)L, which can improve the reaction of Fe(II) / Fe(III) with H2O2. Hydroxyl radicals have strong oxidizing properties and can break organic molecular chains. On the other hand, in the Fe(II)-persulfate advanced oxidation system, Fe(II) and Fe(III) can act as donors, activating persulfate through single electron transfer to generate sulfate radicals. Sulfate radicals have strong oxidizing properties and can break organic molecular chains. The intermediate products of TMAH oxidation are amine organic compounds such as trimethylamine, dimethylamine, and methylamine. Sulfate radicals have a greater oxidative effect on NH bonds in amine groups than hydroxyl radicals. Therefore, hydroxyl radicals and sulfate radicals work synergistically, resulting in a better degradation effect on TMAH wastewater, which can reduce the dosage of complexing agents, Fe(II), persulfate, and other reagents. TMAH molecules are degraded into easily biodegradable small organic molecules through chain scission. These small organic molecules serve as carbon sources, and ammonia nitrogen as a nitrogen source. Under the action of anoxic and aerobic microorganisms, they undergo denitrification and nitrification, respectively, degrading ammonia nitrogen and organic matter in the wastewater. The treated wastewater's NH3-N, total nitrogen (TN), and chemical oxygen demand (COD) indicators meet emission standards.

[0048] The complexing agent, Fe(II) and persulfate used in the present invention have no secondary pollution to the environment, are cheap and readily available, non-toxic and harmless, and are easy to use.

[0049] Preferably, the dosage of Fe(II) is 200-2000 mg / L, for example, 200 mg / L, 400 mg / L, 600 mg / L, 800 mg / L, 1000 mg / L, 1200 mg / L, 1400 mg / L, 1600 mg / L, 1800 mg / L, 2000 mg / L, and the dosage of the complexing agent is 1-30 mg / L, for example, 1 mg / L, 3 mg / L, 5 mg / L, 7 mg / L, 9 mg / L, 11 mg / L, 13 mg / L, 15 mg / L, 17 mg / L, 19 mg / L, 21 mg / L, 23 mg / L, 25 mg / L, 27 mg / L, 29 mg / L, 30 The dosage of persulfate is 500-5000 mg / L, for example, 500 mg / L, 700 mg / L, 900 mg / L, 1100 mg / L, 1300 mg / L, 1500 mg / L, 1700 mg / L, 1900 mg / L, 2100 mg / L, 2300 mg / L, 2500 mg / L, 2700 mg / L, 2900 mg / L, 3100 mg / L, 3300 mg / L, 3500 mg / L, 3700 mg / L, 3900 mg / L, 4100 mg / L, 4300 mg / L, 4500 mg / L, 4700 mg / L, 4900 mg / L, and 5000 mg / L.

[0050] The present invention has found through a large number of experiments that when the dosages of Fe(II), complexing agent and persulfate are within the above ranges, the TMAH oxidation effect is better.

[0051] Specifically, in step S1, the volume ratio of TMAH waste liquid to ammonia nitrogen-containing wastewater is 1:10 to 1:250, for example, 1:10, 1:20, 1:30, 1:40, 1:50, 1:60, 1:70, 1:80, 1:90, 1:100, 1:110, 1:120, 1:130, 1:140, 1:150, 1:160, 1:170, 1:180, 1:190, 1:200, 1:210, 1:220, 1:230, 1:240, and 1:250.

[0052] It should be noted that when the volume ratio of TMAH waste liquid to ammonia nitrogen-containing wastewater is within the above range, the advanced oxidation reaction can proceed. Beyond this range, the advanced oxidation reaction cannot proceed.

[0053] Specifically, the volume ratio of the TMAH waste liquid in step S1 to the ammonia nitrogen-containing wastewater in step S2 is 1:2 to 1:20, for example, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, 1:11, 1:12, 1:13, 1:14, 1:15, 1:16, 1:17, 1:18, 1:19, and 1:20.

[0054] It should be noted that when the volume ratio of the TMAH wastewater in step S1 to the ammonia nitrogen-containing wastewater in step S2 is within the above range, the subsequent denitrification reaction can be carried out. If it exceeds this range, the denitrification reaction cannot be carried out.

[0055] Specifically, in step S2, the pH value is adjusted to 7-7.5, for example, 7, 7.1, 7.2, 7.3, 7.4, or 7.5.

[0056] It should be noted that when the pH value is in the range of 7-7.5, the activity of denitrifying bacteria is high and the denitrification effect is good.

[0057] Preferably, an acid or a base is selected to adjust the pH value. More preferably, the acid is one or more of hydrochloric acid, sulfuric acid or nitric acid, and the base is sodium hydroxide or potassium hydroxide.

[0058] It should be noted that in step S2, the filtration is carried out using a manganese sand filter to remove H2O2 from the ammonia nitrogen wastewater. Since H2O2 has strong oxidizing properties, it will affect the activity of denitrifying bacteria and nitrifying bacteria in step S3.

[0059] Specifically, in step S3, the sludge is partially returned to the first denitrification treatment to enhance the denitrification treatment effect, and the remaining sludge is discharged for treatment.

[0060] Specifically, in step S3, the first denitrification treatment, the first nitrification treatment, the second denitrification treatment, and the second nitrification treatment are sequentially performed in the first anoxic tank, the first aerobic tank, the second anoxic tank, and the second aerobic tank.

[0061] Preferably, a portion of the mixed liquor in the first aerobic tank is returned to the first anoxic tank to provide nitrate (NO3 - ) as an electron acceptor to enhance the denitrification efficiency of the anoxic tank.

[0062] It should be noted that the water entering the first anoxic tank is wastewater that has undergone a second pH adjustment. Denitrification reaction is carried out in an anoxic environment. Denitrification bacteria use the small molecular organic matter degraded by TMAH molecules as a carbon source and the oxygen of nitrate in the reflux liquid of the first aerobic tank as an electron acceptor to carry out respiration and life activities, reducing nitrate nitrogen to gaseous nitrogen. The first aerobic tank receives the wastewater after denitrification in the first anoxic tank, and carries out nitrification reaction in an aerobic environment to degrade ammonia nitrogen and organic matter in the wastewater. A portion of the mixed liquid in the first aerobic tank flows back to the first anoxic tank. The second anoxic tank receives the wastewater after ammonia nitrogen degraded in the first aerobic tank, and carries out denitrification reaction again in an anoxic environment to further carry out biological denitrification and reduce the nitrogen content in the wastewater. The second aerobic tank receives the wastewater after denitrification in the second anoxic tank, and carries out nitrification reaction again in an aerobic environment to further remove ammonia nitrogen and organic matter in the wastewater.

[0063] Sedimentation is carried out in a sedimentation tank, with a portion of the sludge flowing back to the first anoxic tank, and the remaining portion being discharged as excess sludge. After treatment with the present method, the TMAH wastewater is fully recycled, and the NH3-N, TN, and COD levels in the ammonia nitrogen wastewater meet the indirect emission standards set forth in the current national standard, GB39731, "Emission Standard for Water Pollutants in the Electronics Industry," namely, NH3-N ≤ 45 mg / L, TN ≤ 70 mg / L, and COD ≤ 500 mg / L.

[0064] Another specific embodiment of the present invention is as follows Figure 1 As shown, a system for treating ammonia-nitrogen-containing wastewater using integrated circuit TMAH wastewater is disclosed. The system includes a TMAH wastewater pretreatment unit and an ammonia-nitrogen-containing wastewater treatment unit. After being treated by the TMAH wastewater pretreatment unit, the TMAH wastewater enters the ammonia-nitrogen-containing wastewater treatment unit as a carbon raw material for treating ammonia-nitrogen-containing wastewater.

[0065] Specifically, the TMAH waste liquid pretreatment unit includes a waste liquid tank, a first pH adjustment tank, a first homogenization tank and a reaction tank which are connected in sequence according to the process flow.

[0066] Specifically, the ammonia nitrogen-containing wastewater treatment unit includes a raw water tank, a manganese sand filter, a second equalization tank, a second pH adjustment tank, a first anoxic tank, a first aerobic tank, a second anoxic tank, a second aerobic tank and a sedimentation tank connected in sequence according to the process flow.

[0067] Specifically, the raw water tank is also connected to the first equalization tank, the reaction tank is also connected to the second equalization tank, and the sedimentation tank is also connected to the first anoxic tank.

[0068] It should be noted that the waste liquid tank receives TMAH waste liquid discharged from the production process and adjusts the amount of waste liquid; the first pH adjustment tank is used to adjust the pH value of the TMAH waste liquid, and the wastewater after pH adjustment is added with a reagent in the first homogenizing tank, and part of the ammonia nitrogen-containing wastewater in the raw water tank is added to the first homogenizing tank for uniform mixing; the wastewater after uniform mixing enters the reaction tank for reaction, and the TMAH waste liquid is degraded in the reaction tank.

[0069] The raw water tank receives ammonia nitrogen-containing wastewater discharged from the production process. The ammonia nitrogen-containing wastewater enters the manganese sand filter for treatment to remove H2O2 from the wastewater. The TMAH waste liquid is degraded to produce small molecular organic matter, which then enters the second homogenization tank from the reaction tank to be evenly mixed with the ammonia nitrogen-containing wastewater from which H2O2 has been removed. It then enters the second pH adjustment tank to adjust the pH value, and then enters the first anoxic tank for denitrification. Denitrifying bacteria reduce nitrate nitrogen and nitrite nitrogen in the wastewater to N2. The first aerobic tank undergoes nitrification in an aerobic environment. Nitrifying bacteria degrade ammonia nitrogen in the wastewater into nitrate nitrogen and nitrite nitrogen, while also degrading organic matter. The second anoxic tank undergoes another denitrification reaction in an anoxic environment to further degrade nitrate nitrogen and nitrite nitrogen in the wastewater. The second aerobic tank undergoes another nitrification reaction in an aerobic environment to further degrade ammonia nitrogen and organic matter in the wastewater. The sedimentation tank separates the mixed liquid from the second aerobic tank into mud and water, and discharges the supernatant.

[0070] Part of the sludge in the sedimentation tank is returned to the first anoxic tank, and the other part is discharged from the system as residual sludge.

[0071] The system of the present invention saves equipment investment and operating costs, is simple to operate, is environmentally friendly, and is convenient for large-scale industrial promotion and application.

[0072] The technical solution of the present invention is further explained below in conjunction with specific embodiments.

[0073] Example 1

[0074] like Figure 1 As shown, a system for treating ammonia-nitrogen-containing wastewater using integrated circuit TMAH wastewater of this embodiment includes a TMAH wastewater pretreatment unit and an ammonia-nitrogen-containing wastewater treatment unit. After being treated by the TMAH wastewater pretreatment unit, the TMAH wastewater enters the ammonia-nitrogen-containing wastewater treatment unit as a carbon raw material for treating ammonia-nitrogen-containing wastewater.

[0075] Specifically, the TMAH waste liquid pretreatment unit includes a waste liquid tank, a first pH adjustment tank, a first homogenization tank and a reaction tank which are connected in sequence according to the process flow.

[0076] The ammonia nitrogen-containing wastewater treatment unit includes a raw water tank, a manganese sand filter, a second equalization tank, a second pH adjustment tank, a first anoxic tank, a first aerobic tank, a second anoxic tank, a second aerobic tank and a sedimentation tank connected in sequence according to the process flow.

[0077] The raw water tank is also connected to the first equalization tank, the reaction tank is also connected to the second equalization tank, and the sedimentation tank is also connected to the first anoxic tank.

[0078] Example 2

[0079] A method for treating ammonia-nitrogen-containing wastewater using the system of Example 1 comprises the following steps:

[0080] Step S1: collecting TMAH waste liquid discharged from the production process in a waste liquid tank, adding hydrochloric acid to adjust the pH value of the TMAH waste liquid to 4.5-5 in a first pH adjustment tank, adding a portion of ammonia nitrogen-containing wastewater and a reagent, performing a first homogenization treatment in a first homogenization tank and TMAH oxidation treatment in a reaction tank, to obtain oxidized TMAH waste liquid;

[0081] The reagents include ferrous sulfate, EDTA and PDS, the dosage of ferrous sulfate is 1200 mg / L, the dosage of EDTA is 12 mg / L, the dosage of PDS is 3200 mg / L, and the volume ratio of TMAH waste liquid to ammonia nitrogen-containing wastewater is 1:90;

[0082] Step S2: After filtering another portion of the ammonia nitrogen-containing wastewater through a manganese sand filter, the oxidized TMAH wastewater is added and homogenized for a second time in a second homogenization tank, and HCl or NaOH is added in a second pH adjustment tank to adjust the pH value to 7-7.5 for a second time to obtain pretreated ammonia nitrogen-containing wastewater;

[0083] The volume ratio of the TMAH wastewater in step S1 to the ammonia nitrogen-containing wastewater in step S2 is 1:5.

[0084] Step S3: sequentially subjecting the pretreated ammonia nitrogen-containing wastewater to a first denitrification treatment in a first anoxic tank, a first nitrification treatment in a second aerobic tank, a second denitrification treatment in a second anoxic tank, a second nitrification treatment in a second aerobic tank, and a sedimentation treatment in a sedimentation tank, and separation to obtain treated wastewater and sludge;

[0085] Part of the mixed liquid in the first aerobic tank flows back to the first anoxic tank, part of the sludge in the sedimentation tank flows back to the first anoxic tank, and the other part is discharged as residual sludge into the system.

[0086] Example 3

[0087] The method for treating ammonia nitrogen-containing wastewater in this embodiment is similar to that in Example 2, except that:

[0088] In step S1, the reagents include ferrous chloride, EDDS and PMS, the dosage of ferrous chloride is 200 mg / L, the dosage of EDDS is 30 mg / L, the dosage of PMS is 500 mg / L, and the volume ratio of TMAH waste liquid to ammonia nitrogen-containing wastewater is 1:250;

[0089] In step S1, the volume ratio of the TMAH waste liquid to the ammonia nitrogen-containing wastewater in step S2 is 1:20.

[0090] Example 4

[0091] The method for treating ammonia nitrogen-containing wastewater in this embodiment is similar to that in Example 2, except that:

[0092] In step S1, the reagents include ferrous sulfate, NTA and PDS, the dosage of ferrous sulfate is 2000 mg / L, the dosage of NTA is 1 mg / L, the dosage of PDS is 5000 mg / L, and the volume ratio of TMAH waste liquid to ammonia nitrogen-containing wastewater is 1:10;

[0093] In step S1, the volume ratio of the TMAH waste liquid to the ammonia nitrogen-containing wastewater in step S2 is 1:2.

[0094] Comparative Example 1

[0095] The method for treating ammonia nitrogen-containing wastewater in this comparative example is similar to that in Example 2, except that, in step S1, the volume ratio of TMAH waste liquid to ammonia nitrogen-containing wastewater is 1:5.

[0096] Comparative Example 2

[0097] The method for treating ammonia nitrogen-containing wastewater in this comparative example is similar to that in Example 2, except that, in step S1, the dosage of ferrous sulfate is 100 mg / L.

[0098] Comparative Example 3

[0099] The method for treating ammonia nitrogen-containing wastewater in this comparative example is similar to that in Example 2, except that in step S1, the dosage of EDTA is 0.5 mg / L.

[0100] Comparative Example 4

[0101] The method for treating ammonia nitrogen-containing wastewater in this comparative example is similar to that in Example 2, except that in step S1, the dosage of PDS is 400 mg / L.

[0102] Comparative Example 5

[0103] The method for treating ammonia nitrogen-containing wastewater in this comparative example is similar to that in Example 2, except that the volume ratio of the TMAH waste liquid in step S1 to the ammonia nitrogen-containing wastewater in step S2 is 1:1.

[0104] Test Example 1

[0105] The methods of Examples 2-4 and Comparative Examples 1-5 were used to treat wastewater from a 12-inch integrated circuit factory, wherein the TMAH wastewater concentration was 2.38% and the discharge volume was 5.5m 3 / h, pH is 9-10. The amount of ammonia nitrogen wastewater is 650m 3 / h, NH3-N concentration is 350-400mg / L, H2O2 concentration is 3800-4000mg / L, COD is 120-130mg / L.

[0106] The test results of NH3-N content, TN content and COD content in the treated wastewater are shown in Table 1.

[0107] Table 1

[0108] Group <![CDATA[NH3-N(mg / L)]]> TN (mg / L) COD (mg / L) Example 2 21 24 162 Example 3 38 42 255 Example 4 42 47 272 Comparative Example 1 363 585 642 Comparative Example 2 355 540 618 Comparative Example 3 360 590 622 Comparative Example 4 345 565 640 Comparative Example 5 348 573 635

[0109] According to the data in Table 1, when the dosages of ferrous sulfate, EDTA and PDS and the volume ratio of TMAH waste liquid to ammonia nitrogen-containing wastewater are all within the specified range of the present invention, the NH3-N, TN and COD values ​​of the treated effluent are low and meet the emission standards; when the dosage of one of the three agents is lower than the minimum value within the specified range of the present invention and the volume ratio of the waste liquid to the wastewater exceeds the maximum value of the specified range, the NH3-N, TN and COD values ​​of the treated effluent will increase significantly and do not meet the emission standards.

[0110] From this, it can be concluded that for a certain concentration of TMAH wastewater and ammonia nitrogen-containing wastewater, when the dosage of the three reagents, ferrous sulfate, EDTA and PDS, is within the specified range, the effluent NH3-N, TN and COD values ​​meet the emission standards; when the dosage of a certain reagent is reduced to a value close to the specified range, the number of free radicals generated by the advanced oxidation system will decrease, the TMAH wastewater cannot be completely degraded into small molecular organic matter, and cannot provide enough carbon source for the ammonia nitrogen-containing wastewater. The microorganisms cannot degrade the ammonia nitrogen wastewater well, and the NH3-N, TN and COD values ​​of the treated effluent increase, but still meet the emission standards; when the dosage of a certain reagent is reduced to below the minimum value within the specified range or when the volume ratio of TMAH wastewater to ammonia nitrogen-containing wastewater is higher than the specified range, the advanced oxidation reaction can hardly proceed, it is difficult for microorganisms to degrade the ammonia nitrogen wastewater, and the NH3-N, TN and COD values ​​of the treated effluent cannot meet the emission standards.

[0111] Test Example 2

[0112] The degradation rates of TMAH wastewater at different reaction times in different oxidation systems were compared.

[0113] The first oxidation system is Fe(II)-PDS, that is, the added reagents are: ferrous sulfate and PDS;

[0114] The second oxidation system is EDDS-Fe(II)-H2O2, that is, the added reagents are: ferrous sulfate, EDDS and H2O2;

[0115] The third oxidation system is EDDS-Fe(II)-H2O2+Fe(II)-PDS, that is, the added reagents are: ferrous sulfate, EDDS, PDS and H2O2.

[0116] The test method is as follows:

[0117] At room temperature, TMAH solution is prepared in the raw water tank, and the solution enters the mixing tank. The above three groups of reagents are added to the mixing tank, and after being fully stirred, it enters the reaction tank. The solution is discharged after coming out of the reaction tank.

[0118] Specific experimental steps:

[0119] S1: Prepare a 2.38% TMAH solution in the original water tank, stir evenly, and adjust the pH of the solution to 5 with HCl;

[0120] S2: Add three groups of reagents into the mixing tank respectively, stir the reagents evenly, and the solutions enter the reaction tank;

[0121] Group 1: FeSO4 1500mg / L, PDS 3800mg / L;

[0122] Group 2: EDDS 25 mg / L, FeSO4 1500 mg / L, H2O2 4000 mg / L;

[0123] Group 3: EDDS 18 mg / L, FeSO4 1200 mg / L, H2O2 4000 mg / L, PDS 2600 mg / L;

[0124] S3: Within 120 minutes after the start of the reaction, samples were taken every 20 minutes to measure the TMAH concentration.

[0125] The degradation effects of the three oxidation systems on TMAH in water are shown in Table 2. The degradation effects vary with reaction time. Figure 2 As shown, C0 is the initial concentration of TMAH solution, and C is the concentration after a period of reaction.

[0126] Table 2

[0127] Reaction time / min Group 1 (%) Group 2 (%) Group 3 (%) 0 0 0 0 20 11 18 45 40 22 34 67 60 34 49 82 80 42 59 91 100 46 64 97 120 48 66 100

[0128] From Table 2 and Figure 2 It can be seen that when FeSO4 1500 mg / L and PDS 3800 mg / L were added, the Fe(II)-PDS system had a certain degradation effect on TMAH, and the removal rate of TMAH was 48% at 120 min;

[0129] When EDDS25mg / L, FeSO41500mg / L, H2O24000mg / L were added, the EDDS-Fe(II)-H2O2 system had a better degradation effect on TMAH, and the removal rate of TMAH was 66% at 120min.

[0130] When EDDS 18 mg / L, FeSO4 1200 mg / L, H2O2 4000 mg / L, and PDS 2600 mg / L were added, the Fe(II)-PDS+EDDS-Fe(II)-H2O2 system significantly improved the effect, and the TMAH removal rate could reach 100% at 120 min.

[0131] The above test examples prove that the hydroxyl radicals and sulfate radicals generated by the EDDS-Fe(II)-H2O2+Fe(II)-PDS advanced oxidation system provided by the present invention have a synergistic effect, can reduce the dosage of the reagent, and the method for degrading TMAH in water is more effective.

[0132] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any technician familiar with this technical field within the technical scope disclosed by the present invention should be covered by the scope of protection of the present invention.

Claims

1. A method for treating ammonia-nitrogen-containing wastewater using integrated circuit TMAH waste liquid, characterized in that: The steps include: Step S1: After the pH value of the TMAH waste liquid is adjusted for the first time, a portion of ammonia nitrogen-containing waste water and a reagent are added to perform a first homogenization treatment and a TMAH oxidation treatment in sequence to obtain an oxidized TMAH waste liquid; Step S2: After filtering another portion of the ammonia nitrogen-containing wastewater, the oxidized TMAH wastewater is added thereto, and the mixture is subjected to a second homogenization treatment and a second pH adjustment treatment, to obtain pretreated ammonia nitrogen-containing wastewater; Step S3: sequentially subjecting the pretreated ammonia nitrogen-containing wastewater to a first denitrification treatment, a first nitrification treatment, a second denitrification treatment, a second nitrification treatment, and a precipitation treatment, and separating the treated wastewater and sludge.

2. The method for treating ammonia-nitrogen-containing wastewater using integrated circuit TMAH waste liquid according to claim 1, wherein: In step S1, an acid is used to adjust the pH value to 4-7.

3. The method for treating ammonia-nitrogen-containing wastewater using integrated circuit TMAH waste liquid according to claim 1, wherein: In step S1, the reagent includes divalent iron, a chelating agent and persulfate.

4. A method for treating ammonia-nitrogen-containing wastewater using integrated circuit TMAH waste liquid according to claim 3, characterized in that: The divalent iron includes one or more of ferrous sulfate, ferrous nitrate or ferrous chloride; The complexing agent is one or more of ethylenediaminetetraacetic acid, N-N'-ethylenediaminedisuccinic acid, nitrilotriacetic acid, and citric acid; The persulfate is peroxymonosulfate and / or peroxydisulfate.

5. The method for treating ammonia-nitrogen-containing wastewater using integrated circuit TMAH waste liquid according to claim 3, wherein: The dosage of the divalent iron is 200-2000 mg / L, the dosage of the complexing agent is 1-30 mg / L, and the dosage of the persulfate is 500-5000 mg / L.

6. The method for treating ammonia-nitrogen-containing wastewater using integrated circuit TMAH waste liquid according to any one of claims 1 to 5, characterized in that: In step S1, the volume ratio of TMAH waste liquid to ammonia nitrogen-containing wastewater is 1:10 to 1:

250.

7. The method for treating ammonia-nitrogen-containing wastewater using integrated circuit TMAH waste liquid according to any one of claims 1 to 5, characterized in that: The volume ratio of the TMAH waste liquid in step S1 to the ammonia nitrogen-containing wastewater in step S2 is 1:2 to 1:

20.

8. The method for treating ammonia-nitrogen-containing wastewater using integrated circuit TMAH waste liquid according to any one of claims 1 to 5, characterized in that: In step S2, the pH value is adjusted to 7-7.

5.

9. The method for treating ammonia-nitrogen-containing wastewater using integrated circuit TMAH waste liquid according to claim 1, characterized in that: In step S3, the sludge is partially returned to the first denitrification process to enhance the denitrification effect, and the remaining sludge is discharged for treatment.

10. The method for treating ammonia-nitrogen-containing wastewater using integrated circuit TMAH waste liquid according to claim 1, characterized in that: In step S3, the first denitrification treatment, the first nitrification treatment, the second denitrification treatment, and the second nitrification treatment are sequentially performed in the first anoxic tank, the first aerobic tank, the second anoxic tank, and the second aerobic tank.

11. A system for treating ammonia-nitrogen-containing wastewater using integrated circuit TMAH waste liquid, characterized in that: The system includes a TMAH waste liquid pretreatment unit and an ammonia nitrogen-containing wastewater treatment unit. After being treated in the TMAH waste liquid pretreatment unit, the TMAH waste liquid enters the ammonia nitrogen-containing wastewater treatment unit as a carbon raw material for treating ammonia nitrogen-containing wastewater.

12. The system for treating ammonia-nitrogen-containing wastewater using integrated circuit TMAH waste liquid according to claim 11, characterized in that: The TMAH waste liquid pretreatment unit comprises a waste liquid tank, a first pH adjustment tank, a first homogenization tank and a reaction tank which are connected in sequence according to the process flow.

13. The system for treating ammonia nitrogen-containing wastewater using integrated circuit TMAH waste liquid according to claim 12, characterized in that: The ammonia nitrogen-containing wastewater treatment unit includes a raw water tank, a manganese sand filter, a second equalization tank, a second pH adjustment tank, a first anoxic tank, a first aerobic tank, a second anoxic tank, a second aerobic tank and a sedimentation tank connected in sequence according to the process flow.

14. The system for treating ammonia-nitrogen-containing wastewater using integrated circuit TMAH waste liquid according to claim 13, characterized in that: The raw water tank is also connected to the first equalization tank, the reaction tank is also connected to the second equalization tank, and the sedimentation tank is also connected to the first anoxic tank.

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