A method for deep reduction of endocrine disrupting toxicity and safe reuse of biochemical tail water

Abstract

The present invention discloses a method for deep reduction of endocrine disrupting toxicity of biochemical tail water and safe reuse, which belongs to the field of deep treatment of sewage and wastewater. The method combines biochemical treatment technology with catalytic ozone oxidation treatment technology to construct a biochemical treatment unit and a catalytic ozone oxidation treatment unit. The biochemical treatment unit includes a sulfur-based denitrification filter, an electrolysis-coupled sulfur-based denitrification filter or an MBR bio-augmentation, which can be selectively used according to the properties of the biochemical tail water and the effluent requirements. The above method can achieve deep reduction of the endocrine disrupting toxicity of the biochemical tail water under normal / low temperature conditions. The present invention adopts different combinations of biochemical treatment units and catalytic ozone oxidation treatment units according to different toxicity reduction requirements and operating conditions, so that the effluent can meet the requirements of the endocrine disrupting toxicity safety threshold and the relevant recycled water quality standards, and has the advantages of simple treatment process, stable effluent and low operating cost, etc., and has broad application prospects in the field of safe recycling of sewage.

Description

Technical Field

[0001] The present invention belongs to the technical field of deep sewage treatment, and more specifically, relates to a method for deep reduction of endocrine disrupting toxicity of biochemical tail water and safe reuse. Background Art

[0002] Advanced wastewater treatment and reuse is a key measure to alleviate water resource shortages. However, with rapid economic and social development, various natural and synthetic chemicals are frequently detected in wastewater, posing potential risks to aquatic ecosystems and human health. They can easily lead to various adverse biological effects, such as endocrine disrupting toxicity, genotoxicity, developmental toxicity, and acute toxicity. Among these, endocrine disrupting toxicity, particularly estrogenic effects, is particularly pronounced in municipal wastewater. Research data indicates that endocrine disruptors are closely linked to reproductive disorders, developmental abnormalities, metabolic disorders, and certain cancers, such as breast, testicular, and prostate cancer, in various organisms, particularly humans. Therefore, there is an urgent need to significantly reduce the endocrine disrupting toxicity of wastewater biochemical tailwater to ensure safe reuse in non-drinking water applications, such as general urban miscellaneous water and landscaping water. The European Commission has established an estradiol equivalent (ES) level of 1 ng-E² / L, which is sufficient to cause endocrine disruption in humans. When the ES level in water is less than 0.4 ng-E² / L, exposure to that water is considered to pose no potential risk to human health.

[0003] Currently, China has developed a number of technologies for upgrading and renovating wastewater treatment plants and ensuring they consistently meet standards through the reorganization of key technologies in the physicochemical and biological treatment stages. However, these technologies remain limited to addressing conventional indicators such as COD, total nitrogen, and total phosphorus, lacking the ability to deeply reduce endocrine-disrupting toxicity and ensure safe reuse. Furthermore, effluent disinfection in wastewater treatment plants mostly relies on chlorination, which produces disinfection byproducts that can easily increase biological toxicity. Chinese patent CN106348551 B discloses a system and method for reducing the toxicity and recycling of biochemical tailwater from the printing and dyeing industry. The system consists of a V-shaped filter, an intermediate water tank, a magnetic resin reactor, an anaerobic pond, a surface flow wetland, and an ecological pond. Magnetic resin is used to remove dissolved organic pollutants from the tailwater by adsorption, reducing color and biotoxicity. The "pond-wetland-pond" combination forms an alternating "anaerobic-aerobic" process to further reduce the concentrations of organic matter, nitrogen, phosphorus, and toxic pollutants in the water, thereby reducing the acute toxicity of the biochemical tailwater and enabling its reuse. However, the treatment process is long, complex, and has relatively high operating costs. Furthermore, no research has been conducted on reducing endocrine disrupting toxicity. Chinese patent CN111606507A discloses an integrated device for disinfecting medical wastewater, including a regulating tank, an integrated wastewater treatment unit, a chlorination disinfection unit, and an ozone generator. However, the use of ozone oxidation technology has high operating costs, and chlorination disinfection can easily increase biotoxicity. Chinese patent CN112707462 A discloses a sequential adsorption treatment method for reducing the toxicity of organic nitrogen industrial biochemical tailwater. This method utilizes a "macroporous-mesoporous-microporous" carbon xerogel sequential adsorption system to enhance the ability to reduce acute toxicity. However, this sequential adsorption system is costly and complex to operate and maintain. Therefore, there is an urgent need to develop cost-effective methods for deeply reducing the endocrine-disrupting toxicity of biochemical tailwater and for its safe reuse. Summary of the Invention

[0004] 1. Problem to be solved

[0005] In response to the problems of high endocrine disrupting toxicity in current biochemical tail water treatment and increased biological toxicity caused by conventional chlorine disinfection, the present invention provides a method for deep reduction of endocrine disrupting toxicity and safe reuse of biochemical tail water. The method combines biochemical treatment technology with catalytic ozone oxidation treatment technology to construct a biochemical treatment unit and a catalytic ozone oxidation treatment unit. The biochemical treatment unit includes a sulfur-based denitrification filter, an electrolysis-coupled sulfur-based denitrification filter or an MBR biological enhancement, which can be selectively used according to the properties of the biochemical tail water and the effluent requirements. The above method can achieve deep reduction of the endocrine disrupting toxicity of biochemical tail water under normal / low temperature conditions. After treatment, the biochemical tail water can meet the reuse water quality requirements of general urban miscellaneous water, greening water and other non-drinking water scenarios.

[0006] 2. Technical solution

[0007] In order to solve the above problems, the technical solutions adopted by the present invention are as follows:

[0008] The present invention provides a method for deep reduction of endocrine disrupting toxicity of biochemical tail water and safe reuse, which is based on the total influent COD Cr The biochemical treatment unit is selected according to the requirements of endocrine disruption toxicity of the total effluent, and then combined with the catalytic ozone oxidation treatment unit for treatment. The biochemical treatment unit uses the metabolic degradation of microorganisms on the surface of the filter material and the interception and adsorption function of the biofilm to reduce the toxicity of the biochemical tail water and remove TN and part of the COD; the catalytic ozone oxidation treatment unit uses the strong oxidizing properties of ozone and hydroxyl radicals to oxidize the difficult-to-degrade organic matter in the wastewater, further reduce toxicity and remove COD, and at the same time decolorize and disinfect the effluent, so that the total effluent can be safely discharged or reused.

[0009] Preferably, the biochemical treatment unit is selected as follows:

[0010] (1) When the total influent COD Cr When the concentration of toxic substances in the effluent is ≥80mg / L and the total effluent endocrine disrupting toxicity is ≤1.0ng-E2 / L, biochemical scheme I is selected at 16-33℃, i.e., the MBR treatment unit with the addition of compound bacterial agents;

[0011] (2) When the total influent COD Cr When the toxicity of the total effluent is less than 80 mg / L and the endocrine disrupting toxicity is ≤ 1.0 ng-E2 / L, the biochemical scheme II, i.e. the sulfur-based denitrification filter treatment unit, is selected;

[0012] (3) When the total influent COD Cr When the concentration is less than 80 mg / L and the total effluent endocrine disrupting toxicity is ≤0.4 ng-E2 / L, the biochemical scheme III is selected, i.e., the electrolysis-coupled sulfur-based denitrification filter treatment unit.

[0013] Preferably, in the above-mentioned biochemical scheme II and biochemical scheme III, the hydraulic retention time (HRT) of the biochemical tail water entering the above-mentioned treatment unit reactor is 0.8 to 4 hours.

[0014] Preferably, the composite bacterial agent in the above-mentioned biochemical scheme I is composed of Nitratireductor, Meganema, Sphingobium and Gemmobacter, with their proportions being 30% to 40%, 30% to 40%, 5% to 15% and 5% to 10% respectively, and their concentration is not less than 20 g / L (dry weight, measured at 105°C).

[0015] Preferably, the dosage of the liquid composite bacterial agent is 1% to 5% of the effective volume of the MBR reaction tank.

[0016] Preferably, the preparation method of the above-mentioned composite bacterial agent comprises: taking 4 to 8 aerobic activated sludges from different sources, acclimating the aerobic activated sludges at room temperature with simulated municipal biochemical tail water (wherein progesterone, nonylphenol, bisphenol A, estradiol, estriol, ethinylestradiol and estrone are added, the concentration is 500 ng / L, and the concentration is subsequently increased to 1 μg / L, 2 μg / L, and 5 μg / L) in a fully automatic continuous water inlet mode of 0.3 L / h, and measuring the effluent during the acclimation process. The content of endocrine disrupting substances shall be controlled, and the acclimation time shall be no less than 6 months; the acclimated aerobic activated sludge shall be selected, and the sewage from the above sources shall be compounded in sequence according to the volume ratio of 50%, 20%, 20% and 10%; at room temperature, the compound bacterial agent shall be cultured in a fully automatic continuous water inlet mode of 5L / h to simulate municipal biochemical tail water (to which progesterone, nonylphenol, bisphenol A, estradiol, estriol, ethinylestradiol and estrone are added, and the concentration is 5μg / L), and the culturing time shall be no less than 1 month.

[0017] Preferably, the filter material of the sulfur-based denitrification filter is composed of sulfur, siderite and ceramsite, and the volume proportions thereof are (20% to 30%): (20% to 40%): (40% to 60%) respectively.

[0018] Preferably, the treatment temperature of the sulfur-based denitrification filter is 8-33°C.

[0019] Preferably, the treatment temperature of the sulfur-based denitrification filter is 8-16° C., and denitrification treatment can also be performed at low temperatures.

[0020] Preferably, the temperature of the electrolysis-coupled sulfur-based denitrification filter treatment is 8-33°C.

[0021] Preferably, the applied voltage intensity of the electrolysis-coupled sulfur-based denitrification filter is 2 to 5 V, and the electrolysis time is 12 to 24 h / d.

[0022] Preferably, the O3 / COD ratio of the catalytic ozone oxidation unit is 2.5-5.5, the catalyst dosage is 4-10 g / L, the contact reaction time is 15-35 min, and the catalyst promotes the catalytic decomposition of ozone and the generation of free radicals.

[0023] Preferably, the active ingredients of the above catalyst are CuO and CeO2, wherein the mass fraction of CuO is 3% to 8%, and the mass fraction of CeO2 is 8% to 15%.

[0024] Preferably, the carrier of the above catalyst is attapulgite.

[0025] Preferably, the endocrine disrupting toxicity concentration of the above-mentioned biochemical tail water is not higher than 18.0 ng-E2 / L (determined by the two-hybrid yeast method, expressed as estradiol (E2) equivalent).

[0026] 3. Beneficial effects

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] (1) The present invention provides a method for deep reduction of endocrine disrupting toxicity and safe reuse of biochemical tail water. The method combines biochemical treatment technology with catalytic ozone oxidation treatment technology to construct a biochemical treatment unit and a catalytic ozone oxidation treatment unit. The biochemical treatment unit includes a sulfur-based denitrification filter, an electrolytic coupled sulfur-based denitrification filter or an MBR biological enhancement. Microorganisms attached to the surface of the filter material metabolize and degrade endocrine disrupting substances, converting them into harmless substances and using them for their own growth, thereby reducing the toxicity of the wastewater. In the catalytic ozone oxidation treatment unit, toxic substances are strongly oxidized and degraded under the influence of ozone and catalytic ozone to produce hydroxyl radicals, thereby further reducing the toxicity of the wastewater. The method can be selectively used according to the properties of the biochemical tail water and the effluent requirements. The above method can achieve deep reduction of the endocrine disrupting toxicity of the biochemical tail water under normal / low temperature conditions, and can achieve the requirement of reducing the endocrine disrupting toxicity in the biochemical tail water to less than 1ng-E2 / L. Furthermore, combined with electrolytic coupling, the endocrine disrupting toxicity in the biochemical tail water can be reduced to less than 0.4ng-E2 / L. After treatment, the biochemical tail water can meet the reuse water quality requirements for non-drinking water scenarios such as general urban miscellaneous water and greening water.

[0029] (2) The present invention provides a method for deep reduction of endocrine disrupting toxicity of biochemical tail water and safe reuse. The method adopts catalytic ozone oxidation unit for terminal treatment of biochemical tail water, thereby avoiding the increase of biological toxicity caused by disinfection by-products produced after conventional chlorination disinfection. The treated effluent can be directly discharged and reused safely.

[0030] (3) The present invention provides a method for deep reduction of endocrine disrupting toxicity and safe reuse of biochemical tail water. The method has a short process flow, simple operation, good endocrine disrupting toxicity reduction effect, stable effluent water quality, and can be used for miscellaneous water such as urban greening and industrial reuse water, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a technical solution diagram of the present invention. DETAILED DESCRIPTION

[0032] The present invention will be further described below with reference to specific embodiments.

[0033] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains; the term "and / or" used herein includes any and all combinations of one or more of the associated listed items.

[0034] In the following embodiment, a method for deep reduction of endocrine disrupting toxicity of biochemical tail water and safe reuse is described. The method is based on the total influent COD Cr The biochemical treatment unit is selected to meet the requirements of endocrine disruption toxicity of the total effluent, and then combined with the catalytic ozone oxidation treatment unit for treatment. The biochemical treatment unit uses the metabolic degradation of microorganisms on the surface of the filter material and the interception and adsorption function of the biofilm to reduce the toxicity of the biochemical tail water and remove TN and part of the COD. The catalytic ozone oxidation treatment unit uses the strong oxidizing properties of ozone and hydroxyl radicals to oxidize the difficult-to-degrade organic matter in the wastewater, further reduce toxicity and remove COD, and at the same time decolorize and disinfect the effluent. The total effluent can be safely discharged or reused. Specifically including:

[0035] S1: The selection of biochemical treatment units is carried out as follows:

[0036] (1) When the total influent COD Cr When the concentration is ≥80mg / L and the total effluent endocrine disrupting toxicity is ≤1.0ng-E2 / L, the MBR treatment unit with compound bacterial agent is selected at 16-33℃ (biochemical scheme I);

[0037] (2) When the total influent COD Cr When the concentration is less than 80 mg / L and the total effluent endocrine disrupting toxicity is ≤1.0 ng-E2 / L, the sulfur-based denitrification filter treatment unit (biochemical scheme II) should be selected;

[0038] (3) When the total influent COD Cr When the concentration is <80mg / L and the total effluent endocrine disrupting toxicity is ≤0.4ng-E2 / L, the electrolysis-coupled sulfur-based denitrification filter treatment unit (biochemical scheme III) is selected.

[0039] S2: Process operation: The biochemical tail water enters the biochemical treatment unit selected in step 1) for treatment, and then enters the catalytic ozone oxidation unit to further reduce the endocrine disrupting toxicity. The total effluent can be safely discharged or reused.

[0040] In the following embodiment, the compound bacterial agent is composed of Nitratireductor, Meganema, Sphingobium and Gemmobacter, which account for 35%, 32%, 10% and 7% respectively, and the liquid concentration is 22g / L (dry weight, measured at 105°C). The preparation process of the compound bacterial agent is as follows: aerobic activated sludge from 6 different sources (two municipal sewage treatment plants, two pharmaceutical plants, two printing and dyeing plants, and aerobic pool sludge from sewage treatment plants in electronic industrial parks) is taken, and at room temperature, municipal biochemical tail water is simulated (progesterone, nonylphenol, bisphenol A, estradiol, estriol, ethinylestradiol and estrone are added, and the concentration is 500ng / L, and the concentration is subsequently increased to 1μg / L, 2μg / L, and 5μg / L) and the aerobic activated sludge is acclimated respectively in a fully automatic continuous water inlet mode of 0.3L / h. During the acclimation process, The endocrine-disrupting substance content in the effluent was measured, and the acclimation period was no less than 6 months. Acclimated aerobic activated sludge was selected and compounded with wastewater from two municipal sewage treatment plants, two pharmaceutical plants, a printing and dyeing plant, and an electronics industrial park at volume ratios of 50%, 20%, 20%, and 10%, respectively. The compounded inoculum was cultured at room temperature using a 5L / h fully automated continuous water inlet method, simulating municipal biochemical tailwater (to which progesterone, nonylphenol, bisphenol A, estradiol, estriol, ethinylestradiol, and estrone were added at a concentration of 5 μg / L) for no less than 1 month. After completion of the incubation period, metagenomic microbial sequencing of the compounded inoculum revealed that the microorganisms were composed of Nitratireductor, Meganema, Sphingobium, and Gemmobacter, with proportions of 30%-40%, 30%-40%, 5%-15%, and 5%-10%, respectively, with concentrations no less than 20g / L (dry weight, measured at 105°C).

[0041] The catalytic components of the catalyst in the following examples are CuO and CeO2, wherein the mass fraction of CuO is 4%-6%, and that of CeO2 is 8%-12%, and the carrier is attapulgite.

[0042] Example 1

[0043] In this embodiment, the treatment object is the biochemical tail water of a municipal sewage treatment plant (C / N is about 4), and the main water quality indicators are: endocrine disrupting toxicity 14-18 ng-E2 / L, COD 45-70 mg / L, TN 13-20 mg / L. The "electrolysis coupled sulfur-based denitrification filter + catalytic ozone oxidation" and "sulfur-based denitrification filter + catalytic ozone oxidation" processes of the present invention, as well as "denitrification + catalytic ozone oxidation", "electrolysis coupled sulfur-based denitrification filter + ozone oxidation", "sulfur-based denitrification filter + ozone oxidation" processes and conventional "denitrification filter + ozone oxidation" processes are used to treat the biochemical tail water. The operating parameters are shown in Table 1.

[0044] The biochemical tail water was pumped into the above-mentioned process reactor in a fully automatic continuous water inlet mode of 1L / h. After 28 days of stable operation, the endocrine disrupting toxicity, COD and TN of the effluent were shown in Table 1. No Escherichia coli was detected in the effluent. After treatment with the technical solution of the present invention, the effluent met the urban greening water standard in "Water Quality of Urban Miscellaneous Water for Urban Wastewater Recycling" (GB / T 18920-2020).

[0045] Example 2

[0046] In this embodiment, the treatment object is the biochemical tail water of a sewage treatment plant in a pharmaceutical industrial park (C / N is about 3.5). The main water quality indicators are: endocrine disrupting toxicity is 15-18 ng-E2 / L, COD is 95-125 mg / L, TN is 20-33 mg / L, ammonia nitrogen is 8.2-10.6 mg / L, and chromaticity is 90-160 degrees. The "MBR (adding composite bacterial agent) + catalytic ozone oxidation" process of the present invention, "MBR + catalytic ozone oxidation", "MBR (adding composite bacterial agent) + ozone oxidation" process and conventional "MBR + ozone oxidation" process are used to treat the biochemical tail water. The operating parameters are shown in Table 2.

[0047] The biochemical tail water was pumped into the above-mentioned process reactor in a fully automatic continuous water inlet mode at 0.5 L / h. After 27 days of stable operation, the endocrine disrupting toxicity, COD, TN and ammonia nitrogen of the effluent were shown in Table 2. No fecal coliform group was detected in the effluent, and the chromaticity was ≤25 degrees. After treatment with the technical solution of the present invention, the effluent met the "Water Quality for Industrial Water Used in Municipal Wastewater Recycling" standard (GB / T19923-2005).

[0048] Example 3

[0049] In this embodiment, the treatment object is the biochemical tail water (C / N is about 4.6) of a sewage treatment plant in a textile printing and dyeing industrial park. The main water quality indicators are: endocrine disrupting toxicity 13-16 ng-E2 / L, COD 95-106 mg / L, TN 14-19 mg / L, ammonia nitrogen 7-11 mg / L, and chromaticity 120-200 degrees. The "MBR (addition of composite bacterial agent) + catalytic ozone oxidation" process of the present invention, "MBR + catalytic ozone oxidation", "MBR (addition of composite bacterial agent) + ozone oxidation" process and conventional "MBR + ozone oxidation" process are used to treat the biochemical tail water. The operating parameters are shown in Table 3.

[0050] The biochemical tail water was pumped into the above-mentioned process reactor in a fully automatic continuous water inlet mode at 0.5 L / h. After 25 days of stable operation, the endocrine disrupting toxicity, COD, TN and ammonia nitrogen of the effluent were shown in Table 3. No fecal coliform group was detected in the effluent, and the chromaticity was ≤30 degrees. After treatment by the present invention, the effluent met the "Water Quality for Industrial Water Used in Municipal Wastewater Recycling" standard (GB / T19923-2005).

[0051] Example 4

[0052] In this embodiment, the treatment object is the biochemical tail water (C / N ratio is about 3) of a sewage treatment plant in an electronic industrial park. The main water quality indicators are: endocrine disrupting toxicity 5-8 ng-E2 / L, COD 30-40 mg / L, and TN 8-12 mg / L. The "electrolysis coupled sulfur-based denitrification filter + catalytic ozone oxidation" process of the present invention, "denitrification + catalytic ozone oxidation", "electrolysis coupled sulfur-based denitrification filter + ozone oxidation" process, and conventional "denitrification filter + ozone oxidation" process are used to treat the biochemical tail water. The operating parameters are shown in Table 4.

[0053] The biochemical tail water was pumped into the above-mentioned process reactor in a fully automatic continuous water inlet mode at 0.5 L / h. After 28 days of stable operation, the endocrine disrupting toxicity, COD and TN of the effluent were shown in Table 4. No fecal coliform group was detected in the effluent. After treatment by the present invention, the effluent met the "Water Quality for Industrial Water Used in Municipal Wastewater Recycling" standard (GB / T19923-2005).

[0054] Table 1 Water quality of biochemical tail water after different process treatment in Example 1

[0055]

[0056] Table 2 Water quality of biochemical tail water after different process treatment in Example 2

[0057]

[0058] Table 3 Water quality of biochemical tail water after different process treatment in Example 3

[0059]

[0060] Table 4 Water quality of biochemical tail water after different process treatment in Example 4

[0061]

Claims

1. A method for deep reduction of endocrine disrupting toxicity and safe reuse of biochemical tail water, characterized in that: The method comprises selecting a biochemical treatment unit based on the total influent COD Cr and the total effluent endocrine disrupting toxicity requirements, and then combining the treatment with a catalytic ozone oxidation treatment unit; the endocrine disrupting toxicity concentration of the biochemical tail water is not higher than 18.0 ng-E2 / L; and the selection of the biochemical treatment unit is carried out in the following manner: (1) When the total influent COD Cr is ≥80 mg / L and the total effluent endocrine disrupting toxicity is ≤1.0 ng-E2 / L, biochemical scheme I is selected at 16-33°C, i.e., the MBR treatment unit with the addition of a composite bacterial agent; (2) When the total influent COD Cr is less than 80 mg / L and the total effluent endocrine disrupting toxicity is ≤1.0 ng-E2 / L, the biochemical scheme II, i.e., the sulfur-based denitrification filter treatment unit, is selected; (3) When the total influent COD Cr is less than 80 mg / L and the total effluent endocrine disrupting toxicity is ≤ 0.4 ng-E2 / L, the biochemical scheme III, i.e., electrolysis coupled with sulfur-based denitrification filter treatment unit, is selected; The hydraulic retention time of the biochemical tail water entering the treatment unit reactor in the biochemical scheme II and biochemical scheme III is 0.8 to 4 hours; The composite bacterial agent in the biochemical scheme I is composed of Nitratireductor, Meganema, Sphingobium and Gemmobacter, with the proportions being 30% to 40%, 30% to 40%, 5% to 15% and 5% to 10% respectively, and the concentration thereof is not less than 20 g / L; The dosage of the compound bacterial agent is 1% to 5% of the effective volume of the MBR reaction tank; The sulfur-based denitrification filter media is composed of sulfur, siderite and ceramsite, and the volume proportions thereof are (20% to 30%): (20% to 40%): (40% to 60%) respectively; The electrolysis-coupled sulfur-based denitrification filter has an applied voltage intensity of 2 to 5 V and an electrolysis time of 12 to 24 h / d; The treatment temperature of the sulfur-based denitrification filter is 8 to 33°C; The O3 / COD ratio of the catalytic ozone oxidation treatment unit is 2.5 to 5.5, the catalyst dosage is 4 to 10 g / L, and the contact reaction time is 15 to 35 minutes.

2. The method for deep reduction of endocrine disrupting toxicity and safe reuse of biochemical tail water according to claim 1, characterized in that: The effective components of the catalyst are CuO and CeO2, wherein the mass fraction of CuO is 3% to 8% and the mass fraction of CeO2 is 8% to 15%.

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