A method for treating water absorbed by organic waste gas from perovskite photovoltaic production.

Abstract

This invention discloses a method for treating organic wastewater from the production of perovskite photovoltaics, belonging to the field of pollutant treatment technology. The method comprises the following steps: pre-treating the organic wastewater from perovskite photovoltaic production with alkali, followed by anaerobic reaction, then treatment with anoxic / aerobic / microaerobic activated sludge systems, and finally adding flocculants for coagulation and sedimentation, thereby achieving the treatment of the organic wastewater. This method effectively removes pollutants from the organic wastewater, and the treatment process is simple with low operating costs.

Description

Technical Field

[0001] This invention relates to the field of pollutant treatment technology, and in particular to a method for treating water absorbed by organic waste gas from the production of perovskite photovoltaics. Background Technology

[0002] The photovoltaic industry, as a new energy source, occupies an important part of the energy structure. Photovoltaic new energy is mainly divided into silicon-based new energy and perovskite-based new energy. The production steps of perovskite new energy mainly include: preparing perovskite photovoltaic thin films using a deposition method; spin-coating a PbI2 precursor solution containing a CsPbX3 seed solution onto a substrate; and heating and annealing to obtain a PbI2 layer (resulting in the perovskite photovoltaic thin film). The organic solvent used in preparing the PbI2 precursor solution containing the CsPbX3 seed solution is DMF / DMSO. Heating and annealing mainly volatilizes the organic solvent DMF / DMSO, with DMF accounting for more than 80%. This volatilized organic solvent is used as waste gas absorption, generating low-concentration DMF-dominated organic solvent absorption water, with a DMF concentration of approximately 0.5–1.5 wt.% and a DMSO concentration of approximately 0.005–0.03 wt.%. Currently, there are few patents or literature methods specifically addressing the treatment of wastewater generated during the production of perovskite new energy photovoltaic panels.

[0003] Therefore, for the treatment of organic waste gas absorption water in the perovskite photovoltaic industry, there is an urgent need to find a treatment method that is simple in process, low in operating cost, and produces stable and compliant effluent. Summary of the Invention

[0004] The purpose of this invention is to provide a method for treating water absorbed by organic waste gas in the production of perovskite photovoltaics, so as to solve the problems existing in the prior art.

[0005] To achieve the above objectives, the present invention provides the following solution:

[0006] One of the technical solutions of the present invention: a method for treating water absorbed by organic waste gas in the production of perovskite photovoltaics, comprising the following steps:

[0007] The organic wastewater from perovskite photovoltaic production undergoes alkalization pretreatment followed by anaerobic reaction. Then, it is treated by anoxic / aerobic / microaerobic activated sludge system (A / O / A biochemical system) and precipitated (precipitation time is 3-5 hours). Flocculants are added to the precipitated wastewater for coagulation reaction (coagulation reaction time is 20-30 minutes), followed by re-precipitation (precipitation time is 2-4 hours), thus achieving the treatment of organic wastewater.

[0008] Furthermore, the main pollutants in the water absorbed by the organic waste gas include N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO);

[0009] In the perovskite photovoltaic production line, the main process uses CsPbX3 seed solution as a PbI2 precursor solution and DMF / DMSO as an organic solvent. After coating, the organic solvent DMF / DMSO (N,N-dimethylformamide / dimethyl sulfoxide) is removed by heating and annealing. The waste gas generated by the organic solvent DMF / DMSO is absorbed by water, resulting in waste gas absorption water containing low concentrations of DMF and DMSO.

[0010] The concentration of N,N-dimethylformamide (the main characteristic organic nitrogen pollutant) in the organic waste gas absorption water is 0.5–1.5 wt.%, and the concentration of dimethyl sulfoxide is 0.05–0.03 wt.%.

[0011] Furthermore, the alkalization pretreatment method specifically includes: adding sodium hydroxide to the organic waste gas absorption water and heating and stirring to react.

[0012] Furthermore, the amount of sodium hydroxide added is 0.5-1% of the mass of the organic waste gas absorption water; the temperature of the heating and stirring reaction is 40-60℃, the stirring speed is 50-100 r / min, and the reaction time is 1-3 h.

[0013] Furthermore, the sludge used in the anaerobic reaction (ammoniation treatment) includes anaerobic granular sludge with a sludge concentration of 10,000–20,000 mg / L; the hydraulic retention time of the anaerobic reaction is 24–72 h.

[0014] Furthermore, the anaerobic reaction is carried out in an anaerobic reactor, which includes a UASB, IC, or EGSB.

[0015] DMF and sodium hydroxide are heated and stirred to form dimethylamine and sodium formate. In a conventional anaerobic reactor, anaerobic granular sludge causes dimethylamine to generate ammonia nitrogen, thereby achieving the ammoniation of organic dimethylamine.

[0016] Furthermore, the anoxic / aerobic / microaerobic (A / O / A) activated sludge system includes a first-stage anoxic tank, a second-stage aerobic tank, and a third-stage microaerobic tank;

[0017] The sludge concentration in the first-stage anoxic tank (first-stage A tank) is 3500-4000 mg / L, the dissolved oxygen content is 0.2-0.5 mg / L, and the hydraulic retention time is 24-48 h.

[0018] The sludge concentration in the second-stage aerobic tank (second-stage O tank) is 3000-4000 mg / L, the dissolved oxygen content is 2-5 mg / L, and the hydraulic retention time is 24-72 h.

[0019] The sludge concentration in the third-stage micro-aerobic tank (third-stage A tank) is 2500–3500 mg / L, the dissolved oxygen content is 0.5–1.0 mg / L, and the hydraulic retention time is 12–24 h.

[0020] Furthermore, the main components of the flocculant include polyaluminum chloride (PAC) and polyacrylamide (PAM).

[0021] Furthermore, the polyaluminum chloride and polyacrylamide are added in solution form, with the concentration of the polyaluminum chloride solution being 10-20 wt.% and the concentration of the polyacrylamide solution being 1-5 wt.%.

[0022] The dosage of the polyaluminum chloride solution is 0.5-1.5% of the wastewater mass; the dosage of the polyacrylamide solution is 0.05-0.15% of the wastewater mass.

[0023] The second technical solution of the present invention: a wastewater treatment method for perovskite photovoltaic production, comprising the following steps:

[0024] The organic waste gas absorption water after the above-mentioned alkalization pretreatment is mixed with other wastewater (domestic sewage, ground flushing water, initial rainwater, etc. generated in the factory area and workshop) and subjected to anaerobic reaction. Then, it is treated by anoxic / aerobic / microaerobic activated sludge system (A / O / A biological system) and flocculant is added for coagulation and sedimentation to achieve the treatment of organic waste gas absorption water.

[0025] The concentrations of COD in other wastewater are 500–100 mg / L, total nitrogen is 50–100 mg / L, ammonia nitrogen is 20–50 mg / L, and total phosphorus is 1–5 mg / L.

[0026] The final effluent obtained after coagulation and sedimentation has COD, SS (suspended solids), ammonia nitrogen, total nitrogen, and total phosphorus emission concentrations that meet the indirect emission standards of the "Emission Standard of Pollutants for Battery Industry" (GB30484-2013) (COD≤150mg / L, SS≤140mg / L, ammonia nitrogen≤30mg / L, total nitrogen≤40mg / L, total phosphorus≤2.0mg / L), and the characteristic pollutant DMF meets the direct emission standards of the "Emission Standard of Water Pollutants for Chemical Industry" (DB32 / 939-2020) (DMF≤2.0mg / L).

[0027] The present invention discloses the following technical effects:

[0028] (1) The method of the present invention can effectively remove pollutants from water by absorbing organic waste gas, and the treatment process of the present invention is simple and has low operating costs.

[0029] (2) The present invention adopts the process concept of “alkalization pretreatment + anaerobic reactor + A / O / A biochemical system + coagulation sedimentation” as the main treatment unit, so that the emission concentrations of COD, SS, ammonia nitrogen and total nitrogen in the final effluent meet the indirect emission standards of the “Emission Standard of Pollutants for Battery Industry” (GB 30484-2013) and the characteristic pollutant DMF meets the direct emission standards of the “Emission Standard of Water Pollutants for Chemical Industry” (DB32 / 939-2020).

[0030] Alkalinization pretreatment: DMF reacts with sodium hydroxide under heated stirring conditions to produce dimethylamine and sodium formate; Anaerobic reactor: mainly utilizes the strong reducing conditions in the anaerobic reactor to ammonify dimethylamine under microbial conditions, generating ammonia nitrogen, and degrading sodium formate and some DMSO and other small organic matter into carbon dioxide and small molecule compounds; A / O / A biological system: mainly nitrifies / denitrates ammonia nitrogen in the anaerobic reactor to achieve denitrification removal of ammonia nitrogen, while degrading and removing COD, TP and other substances in the wastewater, ultimately achieving the standard discharge of wastewater. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a schematic diagram of the wastewater treatment process for the production of perovskite photovoltaics according to the present invention. Detailed Implementation

[0033] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0034] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0035] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0036] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be obvious to those skilled in the art. This application specification and embodiments are merely exemplary.

[0037] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0038] The organic waste gas absorption water containing DMF in this invention is the organic solvent waste gas absorption water generated by a perovskite photovoltaic production enterprise (Shandong) during the production of perovskite photovoltaics. The main process of perovskite photovoltaic production is as follows: using a PbI2 precursor solution of CsPbX3 seed solution, using DMF / DMSO as organic solvent, and heating and annealing after coating to remove the organic solvent DMF / DMSO (N,N-dimethylformamide / dimethyl sulfoxide), the waste gas generated by the organic solvent DMF / DMSO is absorbed by water, resulting in organic waste gas absorption water containing a low concentration of DMF (DMF concentration is 0.5-1.5 wt.%, DMSO concentration is 0.005-0.03 wt.%).

[0039] Example 1

[0040] A method for treating water absorbed from organic waste gas produced in perovskite photovoltaics:

[0041] (1) Organic waste gas absorption water containing DMF (DMF concentration of 0.5 wt.% and DMSO concentration of 0.005 wt.%) is introduced into a collection tank, and then introduced into an alkalization pretreatment system for alkalization pretreatment. The amount of sodium hydroxide added during alkalization pretreatment is 0.5% of the mass of organic waste gas absorption water. The temperature of alkalization pretreatment is 40℃, the mechanical stirring speed is 50 r / min, and the reaction time is 1 h.

[0042] (2) The organic waste gas absorption water (COD concentration of 500 mg / L, total nitrogen concentration of 50 mg / L, ammonia nitrogen concentration of 20 mg / L, and total phosphorus concentration of 1 mg / L) after alkalization pretreatment is introduced into the wastewater biochemical integrated regulation tank.

[0043] (3) The wastewater in the wastewater biochemical integrated regulation tank is fed into the anaerobic reactor (UASB) for anaerobic reaction. The activated sludge is anaerobic granular sludge with a sludge concentration of 10,000 mg / L. The hydraulic retention time of the anaerobic reactor is 24 h. The generated anaerobic sludge enters the sludge treatment system and is disposed of as general solid waste.

[0044] (4) After anaerobic reaction, the wastewater is fed into anoxic / aerobic / microaerobic activated sludge system (A / O / A biochemical system) for treatment, and then into a primary sedimentation tank (the generated sludge is sent to the sludge system and disposed of as general solid waste) for 3 hours for primary sedimentation. Then, the wastewater after sludge removal is fed into a coagulation reaction tank, and flocculants (10 wt.% PAC solution and 1 wt.% PAM solution are added to the coagulation reaction tank for coagulation reaction (reaction time is 20 min). Then, the wastewater is fed into a secondary sedimentation tank for 2 hours for secondary sedimentation (the generated sludge is sent to the sludge system) to obtain the final effluent. The final effluent is discharged into the discharge tank and discharged outside through the discharge tank.

[0045] The anoxic / aerobic / microaerobic activated sludge system consists of a first-stage A tank, a second-stage O tank, and a third-stage A tank.

[0046] The sludge concentration in the first-stage A tank is 3500 mg / L, the dissolved oxygen content is 0.2 mg / L, and the hydraulic retention time is 24 h.

[0047] The sludge concentration in the second-stage O tank is 3000 mg / L, the dissolved oxygen content is 2 mg / L, and the hydraulic retention time is 24 h.

[0048] The sludge concentration in the third-stage A tank is 3000 mg / L, the dissolved oxygen content is 0.5 mg / L, and the hydraulic retention time is 12 h.

[0049] The final effluent concentrations are: COD 120 mg / L, SS 80 mg / L, ammonia nitrogen 15 mg / L, total nitrogen 20 mg / L, and total phosphorus 1.0 mg / L. These concentrations meet the indirect emission standards of the "Emission Standard of Pollutants for Battery Industry" (GB30484-2013) (COD ≤ 150 mg / L, SS ≤ 140 mg / L, ammonia nitrogen ≤ 30 mg / L, total nitrogen ≤ 40 mg / L, total phosphorus ≤ 2.0 mg / L). The concentration of the characteristic pollutant DMF is 0.1 mg / L, meeting the direct emission standards of the "Emission Standard of Water Pollutants for Chemical Industry" (DB32 / 939-2020) (DMF ≤ 2.0 mg / L). The concentration of DMSO is ≤ 0.1 mg / L.

[0050] Example 2

[0051] A method for treating wastewater from perovskite photovoltaic production:

[0052] (1) The organic waste gas absorption water (DMF concentration of 20 mg / L and DMSO concentration of 2 mg / L) prepared by alkalization pretreatment in step (1) of Example 1 is combined with other wastewater (domestic sewage, ground flushing water, initial rainwater, etc., COD concentration of 600 mg / L, total nitrogen concentration of 70 mg / L, ammonia nitrogen concentration of 40 mg / L and total phosphorus concentration of 3 mg / L) and fed into the wastewater biochemical integrated regulation tank.

[0053] (2) The wastewater in the wastewater biochemical integrated equalization tank is fed into the UASB anaerobic reactor for anaerobic reaction. The sludge is controlled to be anaerobic granular sludge with a sludge concentration of 10000 mg / L and the hydraulic retention time of the anaerobic reactor is 24 h.

[0054] (3) After anaerobic reaction, the wastewater is fed into anoxic / aerobic / microaerobic activated sludge system (A / O / A biochemical system) for treatment, and then fed into a primary sedimentation tank (sludge removal system) for 3 hours for primary sedimentation. Then, the sludge-removed wastewater is fed into a coagulation reaction tank, and flocculants (10 wt.% PAC solution and 1 wt.% PAM solution, with PAC solution added at 1.0% of the wastewater mass and PAM added at 0.05% of the wastewater mass) are added to the coagulation reaction tank for 30 minutes. After coagulation, the wastewater is fed into a secondary sedimentation tank for 2 hours for secondary sedimentation (sludge removal system) to obtain the final effluent. The final effluent is discharged into the discharge tank and then discharged outside through the discharge tank.

[0055] The anoxic / aerobic / microaerobic activated sludge system consists of a first-stage A tank, a second-stage O tank, and a third-stage A tank.

[0056] The sludge concentration in the first-stage A tank is 3500 mg / L, the dissolved oxygen content is 0.2 mg / L, and the hydraulic retention time is 24 h.

[0057] The sludge concentration in the second-stage O tank is 3000 mg / L, the dissolved oxygen content is 2 mg / L, and the hydraulic retention time is 24 h.

[0058] The sludge concentration in the third-stage A tank is 3000 mg / L, the dissolved oxygen content is 0.5 mg / L, and the hydraulic retention time is 24 h.

[0059] The final effluent concentrations are: COD 105 mg / L, SS 95 mg / L, ammonia nitrogen 17.5 mg / L, total nitrogen 25 mg / L, and total phosphorus 1.25 mg / L. These concentrations meet the indirect emission standards of the "Emission Standard of Pollutants for Battery Industry" (GB30484-2013) (COD ≤ 150 mg / L, SS ≤ 140 mg / L, ammonia nitrogen ≤ 30 mg / L, total nitrogen ≤ 40 mg / L, total phosphorus ≤ 2.0 mg / L). The concentration of the characteristic pollutant DMF is 0.55 mg / L, meeting the direct emission standards of the "Emission Standard of Water Pollutants for Chemical Industry" (DB32 / 939-2020) (DMF ≤ 2.0 mg / L). The concentration of DMSO is ≤ 0.1 mg / L. A schematic diagram of the treatment process is shown below. Figure 1 .

[0060] Example 3

[0061] A method for treating water absorbed by organic waste gas from perovskite photovoltaic production:

[0062] (1) Organic waste gas absorption water containing DMF (DMF concentration of 1.5 wt.% and DMSO concentration of 0.03 wt.%) is introduced into a collection tank, and then introduced into an alkalization pretreatment system for alkalization pretreatment. The amount of sodium hydroxide added during alkalization pretreatment is 0.5% of the mass of organic waste gas absorption water. The temperature of alkalization pretreatment is 60℃, the mechanical stirring speed is 100 r / min, and the reaction time is 3 h.

[0063] (2) The organic waste gas absorption water (COD concentration of 12000mg / L, total nitrogen concentration of 2600mg / L, ammonia nitrogen concentration of 20mg / L, total phosphorus concentration of 0.2mg / L, and DMF concentration of 35mg / L) after alkalization pretreatment is introduced into the wastewater biochemical integrated regulation tank.

[0064] (3) The wastewater in the wastewater biochemical integrated regulation tank is fed into the anaerobic reactor (UASB) for anaerobic reaction. The sludge is controlled to be anaerobic granular sludge with a sludge concentration of 20,000 mg / L and the hydraulic retention time of the anaerobic reactor is 72 h.

[0065] (4) After anaerobic reaction, the wastewater is fed into anoxic / aerobic / microaerobic activated sludge system (A / O / A biochemical system) for treatment, and then fed into a primary sedimentation tank (sludge removal system) for 5 hours for primary sedimentation. Then, the sludge-removed wastewater is fed into a coagulation reaction tank, and flocculants (10 wt.% PAC solution and 1 wt.% PAM solution are added to the coagulation reaction tank for coagulation reaction (reaction time is 30 min). Then, the wastewater is fed into a secondary sedimentation tank for 4 hours for secondary sedimentation (sludge removal system) to obtain the final effluent. The final effluent is discharged into the discharge tank and discharged outside through the discharge tank.

[0066] The anoxic / aerobic / microaerobic activated sludge system consists of a first-stage A tank, a second-stage O tank, and a third-stage A tank.

[0067] The sludge concentration in the first-stage A tank is 4000 mg / L, the dissolved oxygen content is 0.5 mg / L, and the hydraulic retention time is 48 h.

[0068] The sludge concentration in the second-stage O tank is 4000 mg / L, the dissolved oxygen content is 5.0 mg / L, and the hydraulic retention time is 72 h.

[0069] The sludge concentration in the third-stage A tank is 2500 mg / L, the dissolved oxygen content is 1.0 mg / L, and the hydraulic retention time is 24 h.

[0070] The final effluent concentrations are: COD 110 mg / L, SS 80 mg / L, ammonia nitrogen 20 mg / L, total nitrogen 25 mg / L, and total phosphorus 1.0 mg / L. These concentrations meet the indirect emission standards of the "Emission Standard of Pollutants for Battery Industry" (GB30484-2013) (COD ≤ 150 mg / L, SS ≤ 140 mg / L, ammonia nitrogen ≤ 30 mg / L, total nitrogen ≤ 40 mg / L, total phosphorus ≤ 2.0 mg / L). The concentration of the characteristic pollutant DMF is 0.2 mg / L, meeting the direct emission standards of the "Emission Standard of Water Pollutants for Chemical Industry" (DB32 / 939-2020) (DMF ≤ 2.0 mg / L). The concentration of DMSO is ≤ 0.1 mg / L.

[0071] Example 4

[0072] A method for treating wastewater from perovskite photovoltaic production:

[0073] (1) The organic waste gas absorption water after alkalization pretreatment prepared in step (1) of Example 3 is combined with other wastewater (domestic sewage, ground flushing water, initial rainwater, etc., with COD concentration of 450mg / L, total nitrogen concentration of 55mg / L, ammonia nitrogen concentration of 30mg / L, and total phosphorus concentration of 3mg / L) and fed into the wastewater biochemical integrated regulation tank.

[0074] (2) The wastewater in the wastewater biochemical integrated regulation tank is fed into the anaerobic reactor (IC) for anaerobic reaction. The sludge is controlled to be anaerobic granular sludge with a sludge concentration of 15000 mg / L and the hydraulic retention time of the anaerobic reactor is 72 h.

[0075] (3) After anaerobic reaction, the wastewater is fed into anoxic / aerobic / microaerobic activated sludge system (A / O / A biochemical system) for treatment, and then fed into a primary sedimentation tank (sludge removal system) for 4 hours for primary sedimentation. Then, the sludge-removed wastewater is fed into a coagulation reaction tank, and flocculants (10 wt.% PAC solution and 1 wt.% PAM solution are added to the coagulation reaction tank for coagulation reaction (reaction time is 25 min). Then, the wastewater is fed into a secondary sedimentation tank for 3 hours for secondary sedimentation (sludge removal system) to obtain the final effluent. The final effluent is discharged into the discharge tank and discharged outside through the discharge tank.

[0076] The anoxic / aerobic / microaerobic activated sludge system consists of a first-stage A tank, a second-stage O tank, and a third-stage A tank.

[0077] The sludge concentration in the first-stage A tank is 3500 mg / L, the dissolved oxygen content is 0.3 mg / L, and the hydraulic retention time is 36 h.

[0078] The sludge concentration in the second-stage O tank is 3000 mg / L, the dissolved oxygen content is 3 mg / L, and the hydraulic retention time is 36 h.

[0079] The sludge concentration in the third-stage A tank is 3000 mg / L, the dissolved oxygen content is 0.6 mg / L, and the hydraulic retention time is 18 h.

[0080] The final effluent concentrations are: COD 105 mg / L, SS 100 mg / L, ammonia nitrogen 17.5 mg / L, total nitrogen 30 mg / L, and total phosphorus 1.0 mg / L. These concentrations meet the indirect emission standards of the "Emission Standard of Pollutants for Battery Industry" (GB 30484-2013) (COD ≤ 150 mg / L, SS ≤ 140 mg / L, ammonia nitrogen ≤ 30 mg / L, total nitrogen ≤ 40 mg / L, total phosphorus ≤ 2.0 mg / L). The concentration of the characteristic pollutant DMF is 0.35 mg / L, which meets the direct emission standards of the "Emission Standard of Water Pollutants for Chemical Industry" (DB32 / 939-2020) (DMF ≤ 2.0 mg / L). The concentration of DMSO is ≤ 0.1 mg / L.

[0081] Comparative Example 1

[0082] Same as Example 2, except that step (3) specifically involves: passing the wastewater in the wastewater biochemical integrated regulation tank into the A / O biochemical system for treatment.

[0083] The A / O biological system consists of a first-stage A tank (anoxic tank) and a second-stage O tank (aerobic tank);

[0084] The sludge concentration in the first-stage A tank is 3500 mg / L, the dissolved oxygen content is 0.2 mg / L, and the hydraulic retention time is 24 h.

[0085] The sludge concentration in the second-stage O tank is 4000 mg / L, the dissolved oxygen content is 4.0 mg / L, and the hydraulic retention time is 48 h.

[0086] The final effluent concentrations were: COD 185 mg / L, SS 100 mg / L, ammonia nitrogen 37.5 mg / L, total nitrogen 90 mg / L, and total phosphorus 2.0 mg / L. The emission concentrations of COD, ammonia nitrogen, and total nitrogen did not meet the indirect emission standards of the "Emission Standard of Pollutants for Battery Industry" (GB 30484-2013) (COD ≤ 150 mg / L, SS ≤ 140 mg / L, ammonia nitrogen ≤ 30 mg / L, total nitrogen ≤ 40 mg / L, total phosphorus ≤ 2.0 mg / L). The concentration of the characteristic pollutant DMF was 1.75 mg / L, meeting the direct emission standards of the "Emission Standard of Water Pollutants for Chemical Industry" (DB32 / 939-2020) (DMF ≤ 2.0 mg / L). The concentration of DMSO was ≤ 0.1 mg / L.

[0087] Comparative Example 2

[0088] Same as Example 2, except that the A / O / A biochemical system is replaced with the O / A / O biochemical system.

[0089] The O / A / O biochemical system consists of a first-stage O pool, a second-stage A pool, and a third-stage O pool.

[0090] The sludge concentration in the first-stage O tank is 3000 mg / L, the dissolved oxygen content is 3 mg / L, and the hydraulic retention time is 48 h.

[0091] The sludge concentration in the second-stage A tank is 4000 mg / L, the dissolved oxygen content is 0.4 mg / L, and the hydraulic retention time is 36 h.

[0092] The sludge concentration in the third-stage O tank is 3000 mg / L, the dissolved oxygen content is 2 mg / L, and the hydraulic retention time is 24 h.

[0093] The final effluent concentrations were: COD 120 mg / L, SS 95 mg / L, ammonia nitrogen 17.5 mg / L, total nitrogen 65 mg / L, and total phosphorus 1.25 mg / L. The total nitrogen emission concentration did not meet the indirect emission standards of the "Emission Standard of Pollutants for Battery Industry" (GB 30484-2013) (COD ≤ 150 mg / L, SS ≤ 140 mg / L, ammonia nitrogen ≤ 30 mg / L, total nitrogen ≤ 40 mg / L, total phosphorus ≤ 2.0 mg / L). The concentration of the characteristic pollutant DMF was 0.8 mg / L, meeting the direct emission standards of the "Emission Standard of Water Pollutants for Chemical Industry" (DB32 / 939-2020) (DMF ≤ 2.0 mg / L). The concentration of DMSO was ≤ 0.1 mg / L.

[0094] Comparative Example 3

[0095] Same as Example 1, except that the alkalization pretreatment step (1) is omitted, and the anaerobic reaction is carried out directly using an anaerobic reactor, followed by subsequent treatment using an A / O / A biochemical system.

[0096] The final effluent concentrations were: COD 275 mg / L, SS 135 mg / L, ammonia nitrogen 55 mg / L, total nitrogen 225 mg / L, and total phosphorus 2.25 mg / L. These concentrations did not meet the indirect emission standards of the "Emission Standard of Pollutants for Battery Industry" (GB 30484-2013) (COD ≤ 150 mg / L, SS ≤ 140 mg / L, ammonia nitrogen ≤ 30 mg / L, total nitrogen ≤ 40 mg / L, total phosphorus ≤ 2.0 mg / L). The concentration of the characteristic pollutant DMF was 5.5 mg / L, which did not meet the direct emission standards of the "Emission Standard of Water Pollutants for Chemical Industry" (DB32 / 939-2020) (DMF ≤ 2.0 mg / L). The concentration of DMSO was ≤ 0.1 mg / L.

[0097] Comparative Example 4

[0098] The only difference is that after the alkalization pretreatment step (1), it is mixed with other wastewater and directly treated using the A / O / A biochemical system, without the anaerobic reactor treatment unit.

[0099] The final effluent concentrations were: COD 250 mg / L, SS 140 mg / L, ammonia nitrogen 100 mg / L, total nitrogen 225 mg / L, and total phosphorus 3.0 mg / L. These concentrations did not meet the indirect emission standards of the "Emission Standard of Pollutants for Battery Industry" (GB 30484-2013) (COD ≤ 150 mg / L, SS ≤ 140 mg / L, ammonia nitrogen ≤ 30 mg / L, total nitrogen ≤ 40 mg / L, total phosphorus ≤ 2.0 mg / L). The concentration of the characteristic pollutant DMF was 3.5 mg / L, which did not meet the direct emission standards of the "Emission Standard of Water Pollutants for Chemical Industry" (DB32 / 939-2020) (DMF ≤ 2.0 mg / L). The concentration of DMSO was ≤ 0.1 mg / L.

[0100] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for treating water absorbed by organic waste gas from perovskite photovoltaic production, characterized in that, Includes the following steps: After alkalization pretreatment, the organic waste gas absorption water from perovskite photovoltaic production undergoes anaerobic reaction, and then is treated by anoxic / aerobic / microaerobic activated sludge system before flocculant is added for coagulation and sedimentation, thus achieving the treatment of organic waste gas absorption water. The main pollutants in the organic waste gas absorbed water include N,N-dimethylformamide and dimethyl sulfoxide; The concentration of N,N-dimethylformamide in the organic waste gas absorption water is 0.5–1.5 wt.%, and the concentration of dimethyl sulfoxide is 0.05–0.03 wt.%. The anoxic / aerobic / microaerobic activated sludge system includes a first-stage anoxic tank, a second-stage aerobic tank, and a third-stage microaerobic tank. The sludge concentration in the first-stage anoxic tank is 3500–4000 mg / L, the dissolved oxygen content is 0.2–0.5 mg / L, and the hydraulic retention time is 24–48 h. The sludge concentration in the second-stage aerobic tank is 3000-4000 mg / L, the dissolved oxygen content is 2-5 mg / L, and the hydraulic retention time is 24-72 h. The sludge concentration in the third-stage micro-aerobic tank is 2500–3500 mg / L, the dissolved oxygen content is 0.5–1.0 mg / L, and the hydraulic retention time is 12–24 h.

2. The processing method according to claim 1, characterized in that, The alkalization pretreatment method specifically includes: adding sodium hydroxide to the organic waste gas absorption water and heating and stirring to react.

3. The processing method according to claim 2, characterized in that, The amount of sodium hydroxide added is 0.5-1% of the mass of the organic waste gas absorption water; the temperature of the heating and stirring reaction is 40-60℃, the stirring speed is 50-100 r / min, and the reaction time is 1-3 h.

4. The processing method according to claim 1, characterized in that, The sludge used in the anaerobic reaction includes anaerobic granular sludge with a concentration of 10,000–20,000 mg / L; the hydraulic retention time of the anaerobic reaction is 24–72 h.

5. The processing method according to claim 1, characterized in that, The main components of the flocculant include polyaluminum chloride and polyacrylamide.

6. The processing method according to claim 5, characterized in that, The polyaluminum chloride and polyacrylamide are added in solution form, with the polyaluminum chloride solution having a concentration of 10 wt.% and the polyacrylamide solution having a concentration of 1–5 wt.%. The dosage of the polyaluminum chloride solution is 0.5-1.5% of the wastewater mass; the dosage of the polyacrylamide solution is 0.05-0.15% of the wastewater mass.

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