Method for enhancing biological treatment of high-salt organic wastewater by using plant hormones

Abstract

The present application belongs to the technical field of organic wastewater treatment, and particularly relates to a method for enhancing biological treatment of high-salinity organic wastewater by using plant hormones. In the method, plant hormones are added during the process of aerobic reaction treatment of high-salinity organic wastewater, so that the biological treatment efficiency of high-salinity pharmaceutical wastewater and chemical wastewater can be enhanced, the degradation rate of organic pollutants can be increased by 4.3-57.7%, the total nitrogen removal efficiency can be increased by 7.8-55.0%, the total phosphorus removal efficiency can be increased by 4.0-67.5%, and the microbial activity can be increased by 4.8-56.8%. In addition, the oil content of the microalgae treatment system can be increased by 3.5-14.5%, and the oil yield can be increased by 17.0-95.0%. Therefore, the present application can adjust the growth and metabolism process of microorganisms by using trace plant hormones, resist high-salinity stress, enhance the degradation of organic pollutants, and realize efficient treatment of high-salinity wastewater and accumulation of microalgae biomass resources.

Description

Technical Field

[0001] This invention belongs to the field of organic wastewater treatment technology, specifically relating to a method for enhancing the biological treatment of high-salt organic wastewater using plant hormones. Background Technology

[0002] High salinity in wastewater from chemical and pharmaceutical industries causes problems such as osmotic pressure changes and ion toxicity in microbial cells, severely impacting the effectiveness of biological water treatment. Furthermore, the complex composition of high-salinity wastewater, with its persistent or bioinhibitory organic pollutants, leads to unsatisfactory treatment results. Currently, enhanced biological treatment of high-salinity wastewater mainly relies on the acclimatization and enrichment of salt-tolerant activated sludge or the inoculation of salt-tolerant bacterial agents. While these methods can improve microbial activity to some extent, they have the following drawbacks: acclimatization of microbial communities is time-consuming and slow to show results; they are susceptible to water quality fluctuations and lack environmental adaptability. Inoculation with salt-tolerant bacterial agents cannot maintain stable long-term survival in actual wastewater treatment systems, requiring periodic additions, resulting in high agent consumption and costs. Summary of the Invention

[0003] In view of this, the purpose of the present invention is to provide a method for enhancing the biological treatment of high-salt organic wastewater using plant hormones. This method regulates the microbial signaling system and growth and metabolic processes by using trace amounts of plant hormones, thereby resisting high-salt stress, enhancing the degradation of organic pollutants, and achieving efficient treatment of high-salt organic wastewater and accumulation of microalgal biomass resources.

[0004] To achieve the above objectives, the present invention provides the following technical solution:

[0005] This invention provides a method for enhancing the biological treatment of high-salt organic wastewater using plant hormones, comprising the following steps:

[0006] Plant hormones were added during the aerobic reaction treatment of high-salt organic wastewater.

[0007] The plant hormones include one or more of 6-benzylaminopurine, p-hydroxybenzoic acid, and naphthaleneacetic acid;

[0008] The salinity of the high-salinity organic wastewater is 3-5%.

[0009] Preferably, the concentration of the plant hormone in the high-salt organic wastewater is 1–100 μmol / L.

[0010] Preferably, the aerobic reaction treatment is carried out at room temperature; the aerobic reaction treatment time is 24-48 hours.

[0011] Preferably, the microorganisms used in the aerobic reaction treatment are activated sludge or microalgae.

[0012] Preferably, the activated sludge is activated sludge from a high-salt organic wastewater biological treatment unit or activated sludge from a municipal sewage biological treatment unit.

[0013] Preferably, the concentration of the activated sludge in the high-salt organic wastewater is 3-5 g / L.

[0014] Preferably, the microalgae is *Phaeodactylum tricornutum* or domesticated *Chlorella regularis* FACHB-729.

[0015] Preferably, the concentration of the microalgae in the high-salt organic wastewater is 0.5–1.1 g / L.

[0016] Preferably, the high-salt organic wastewater includes pharmaceutical wastewater containing antibiotic pollutants or coking wastewater containing phenolic pollutants.

[0017] This invention provides a method for enhancing the biological treatment of high-salinity organic wastewater using plant hormones, comprising the following steps: adding plant hormones during the aerobic reaction treatment of the high-salinity organic wastewater; the plant hormones include one or more of 6-benzylaminopurine, p-hydroxybenzoic acid, and naphthaleneacetic acid; the salinity of the high-salinity organic wastewater is 3-5%. In this invention, the addition of plant hormones during the aerobic reaction treatment of high-salinity organic wastewater allows the plant hormones to regulate the microbial signaling system and growth and metabolic processes. By stimulating the division and growth of microorganisms, increasing their number and biological activity, it activates the microbial stress response system, enhances the microorganisms' tolerance to high-salinity environments, thereby resisting high-salinity stress. Furthermore, it enhances the degradation of organic pollutants by altering the metabolic pathways and metabolites produced by the microorganisms, ensuring that the effluent meets discharge standards, while simultaneously promoting the accumulation of bio-oils. Detailed Implementation

[0018] This invention provides a method for enhancing the biological treatment of high-salt organic wastewater using plant hormones, comprising the following steps:

[0019] Plant hormones were added during the aerobic reaction treatment of high-salt organic wastewater.

[0020] The plant hormones include one or more of 6-benzylaminopurine, p-hydroxybenzoic acid, and naphthaleneacetic acid;

[0021] The salinity of the high-salinity organic wastewater is 3-5%.

[0022] Unless otherwise specified, the present invention does not have special requirements on the source of raw materials used, and commercially available products well known to those skilled in the art can be used.

[0023] In this invention, the plant hormone includes one or more of 6-benzylaminopurine, p-hydroxybenzoic acid and naphthaleneacetic acid, preferably 6-benzylaminopurine; the salinity of the high-salt organic wastewater is 3-5%, preferably 3.5-4.5%.

[0024] In this invention, the high-salt organic wastewater preferably includes pharmaceutical wastewater containing antibiotic pollutants or coking wastewater containing phenolic pollutants, more preferably pharmaceutical wastewater containing antibiotic pollutants; the concentration of the plant hormone in the high-salt organic wastewater is preferably 1-100 μmol / L, more preferably 10-50 μmol / L.

[0025] Plant hormone signaling substances can be used to regulate the stress resistance, growth and metabolism, pollutant degradation enzyme expression, and wastewater toxicity reduction of microorganisms in activated sludge during wastewater biological treatment processes. Besides activated sludge systems, microalgae, as potential wastewater treatment organisms, can have their growth, metabolism, and community behavior regulated by plant hormones, and can also synthesize resource-based products such as bio-oils while treating wastewater. This invention utilizes the regulatory effects of plant hormones to enhance the biological treatment efficiency of high-salt organic wastewater. By regulating the microbial signaling system and growth and metabolic processes with trace amounts of plant hormones, it resists high-salt stress, enhances the degradation of organic pollutants, and ultimately promotes the biochemical treatment and resource conversion of high-salt wastewater.

[0026] In this invention, the microorganisms used in the aerobic reaction treatment are preferably activated sludge or microalgae, more preferably activated sludge; the activated sludge is preferably activated sludge from a high-salt organic wastewater biological treatment unit or a municipal sewage biological treatment unit, more preferably activated sludge from a high-salt organic wastewater biological treatment unit; the concentration of the activated sludge in the high-salt organic wastewater is preferably 3-5 g / L, more preferably 4 g / L; the microalgae are preferably *Phaeodactylum tricornutum* or domesticated *Chlorella regularis* FACHB-729, more preferably *Phaeodactylum tricornutum*; the concentration of the microalgae in the high-salt organic wastewater is preferably 0.5-1.1 g / L, more preferably 0.6-1 g / L; the *Phaeodactylum tricornutum* was purchased from Shanghai Guangyu Biotechnology Co., Ltd.; the domesticated *Chlorella regularis* FACHB-729 was purchased from the Freshwater Algae Culture Collection of the Chinese Academy of Sciences.

[0027] In this invention, the aerobic reaction treatment is preferably carried out at room temperature; the aerobic reaction treatment time is preferably 24-48 h, more preferably 24-36 h; the aerobic reaction treatment is preferably carried out under stirring conditions; the stirring rate is preferably 150-300 rpm, more preferably 200-250 rpm.

[0028] In this invention, the residual amount of plant hormones in the water obtained from the aerobic reaction treatment is preferably less than 0.1 μmol / L; the water obtained from the aerobic reaction treatment preferably meets the GB21904-2008 discharge standard: chemical oxygen demand (COD) < 120 mg / L, total nitrogen (TN) < 35 mg / L, and total phosphorus (TP) < 1.0 mg / L; when microalgae are added, the oil content in the water obtained from the aerobic reaction treatment is preferably ≥ 25%, more preferably 25-25.8%, and the oil yield is preferably 0.243-0.267 g / L.

[0029] In this invention, compared with the conventional biological treatment group, the biological treatment group with added plant hormones showed an increase of 4.3–57.7% in the degradation rate of organic pollutants in the effluent, an increase of 7.8–55.0% in the total nitrogen removal efficiency, an increase of 4.0–67.5% in the total phosphorus removal efficiency, and an increase of 4.8–24.5% in microbial activity (microbial respiration rate). Furthermore, the oil content of the microalgae treatment system could be increased by 3.5–14.5%, and the oil yield by 17.0–95.0%.

[0030] The effects of using trace amounts of plant hormones to enhance the biological treatment of high-salt wastewater are as follows:

[0031] (1) Compared with conventional biological treatment groups, the degradation rate of organic matter such as antibiotics in pharmaceutical wastewater increased by 6.1–43.4%, the total nitrogen removal rate increased by 8.8–55.0%, and the total phosphorus removal rate increased by 10.0–67.5%, achieving effluent compliance with GB21904-2008 discharge standards: chemical oxygen demand (COD) <120 mg / L, total nitrogen (TN) <35 mg / L, and total phosphorus (TP) <1.0 mg / L. The microbial respiration rate also increased by 4.8–20.4%. Furthermore, when using microalgae to treat pharmaceutical wastewater, the oil content in the biological treatment group with added plant hormones increased by 3.5–12.5% ​​compared to the conventional biological treatment group, and the oil yield increased by 17.0–62.0%.

[0032] (2) Compared with the conventional biological treatment group, the degradation rate of organic matter such as phenols in coking wastewater increased by 4.3-57.7%, the total nitrogen removal rate increased by 7.8-34.4%, and the total phosphorus degradation and removal rate increased by 4.0-52.0%, achieving effluent compliance with GB16171-2012 indirect discharge standards: chemical oxygen demand (COD) <150 mg / L, total nitrogen (TN) <50 mg / L, and total phosphorus (TP) <3.0 mg / L. The microbial respiration rate increased by 10.2-24.5%. Furthermore, when using microalgae for treatment, the oil content in the biological treatment group with added plant hormones increased by 3.5-14.5% compared to the conventional biological treatment group, and the oil yield increased by 22.5-95.0%.

[0033] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, but they should not be construed as limiting the scope of protection of the present invention.

[0034] Example 1

[0035] Pharmaceutical wastewater was taken from a raw material drug manufacturing plant, with a salinity of 3.75%, COD concentration of 800 mg / L, total nitrogen concentration of 80 mg / L, and total phosphorus concentration of 8 mg / L. In an activated sludge treatment system for high-salinity pharmaceutical wastewater, 1, 10, and 100 μmol / L of 6-benzylaminopurine, p-hydroxybenzoic acid, and naphthaleneacetic acid were added to the aerobic biological treatment unit of a conventional bioreactor. The activated sludge concentration was 4 g / L, the stirring speed was 150 rpm, and the temperature was room temperature. After 48 hours of reaction, the sludge respiration rate increased by 4.8–20.4%, and the effluent COD concentration decreased to 113 mg / L. Compared with Comparative Example 1, the COD degradation rate increased by 6.1–43.4%. Meanwhile, the total nitrogen concentration in the effluent was reduced to 20 mg / L, and the total nitrogen removal rate was increased by 8.8–55.0%. The total phosphorus concentration was reduced to 0.9 mg / L, and the total phosphorus removal rate was increased by 11.3–67.5%. The effluent met the GB21904-2008 discharge standard (chemical oxygen demand COD < 120 mg / L, total nitrogen TN < 35 mg / L, total phosphorus TP < 1.0 mg / L) (Table 1).

[0036] Table 1. Effects of different concentrations of plant hormones on the biological treatment of pharmaceutical wastewater by activated sludge.

[0037]

[0038] Example 2

[0039] Pharmaceutical wastewater was taken from a raw material drug manufacturing plant, with a salinity of 3.75%, COD concentration of 800 mg / L, total nitrogen concentration of 80 mg / L, and total phosphorus concentration of 8 mg / L. In a microalgae (Phaeodactylum tricornutum, purchased from Shanghai Guangyu Biotechnology Co., Ltd.) system for treating high-salinity pharmaceutical wastewater, 1, 10, and 100 μmol / L of 6-benzylaminopurine, p-hydroxybenzoic acid, and naphthaleneacetic acid were added to the aerobic biological treatment unit of a conventional bioreactor. The microalgae biomass was 0.803 g / L, the stirring speed was 150 rpm, and the temperature was room temperature. After 48 hours of reaction, the microalgae biomass increased by 10.0–33.8%, and the effluent COD concentration decreased to 273 mg / L. Compared with Comparative Example 2, the COD degradation rate increased by 6.6–34.8%. Meanwhile, the total nitrogen concentration in the effluent decreased to 42 mg / L, with the total nitrogen removal rate increasing by 10.0–38.8%, and the total phosphorus concentration decreased to 3.1 mg / L, with the total phosphorus removal rate increasing by 10.0–51.3%. Furthermore, the microalgal oil content reached as high as 25.0%, with a final oil yield of 0.243 g / L, representing increases of 3.5–12.5% ​​and 17.0–62.0%, respectively, compared to Comparative Example 2 (Table 2).

[0040] Table 2. Effects of different concentrations of plant hormones on microalgae-based biological treatment of pharmaceutical wastewater

[0041]

[0042]

[0043] The experimental results of Examples 1 and 2 showed that 100 μmol / L 6-benzylaminopurine had the best enhancing effect on the biological treatment of pharmaceutical wastewater. After adding 100 μmol / L 6-benzylaminopurine, the respiration rate of activated sludge and microalgae biomass increased by 20.4% and 33.8%, respectively. Furthermore, in terms of effluent quality, activated sludge was slightly more effective than microalgae. Compared with the conventional biological treatment group, the biological treatment group with added plant hormones achieved an effluent COD concentration as low as 113 mg / L, with a COD degradation rate increased by 43.4%. Simultaneously, the effluent total nitrogen and total phosphorus concentrations were reduced to 20 mg / L and 0.9 mg / L, respectively, with removal rates increased by 55.0% and 67.5%, respectively. The effluent met the GB21904-2008 discharge standard (Chemical Oxygen Demand (COD) < 120 mg / L, Total Nitrogen (TN) < 35 mg / L, Total Phosphorus (TP) < 1.0 mg / L). In addition, the treatment of pharmaceutical wastewater using microalgae resulted in an oil content of 25% and an oil yield of 0.243 g / L, which were 12.5% ​​and 62.0% higher than those in Comparative Example 2, respectively.

[0044] Example 3

[0045] Coking wastewater was taken from a coking plant, with a salinity of 4.55%, COD concentration of 600 mg / L, total nitrogen concentration of 90 mg / L, and total phosphorus concentration of 10 mg / L. In an activated sludge treatment system for high-salinity coking wastewater, 1, 10, and 100 μmol / L of 6-benzylaminopurine, p-hydroxybenzoic acid, and naphthaleneacetic acid were added to the aerobic biological treatment unit of a conventional bioreactor. The sludge concentration was 4 g / L, the stirring speed was 150 rpm, and the temperature was room temperature. After 48 hours of reaction, the activated sludge respiration rate increased by 10.2–24.5%, and the effluent COD concentration decreased to 117 mg / L. Compared with Comparative Example 3, the COD removal rate increased by 4.3–32.0%. Meanwhile, the total nitrogen concentration in the effluent decreased to 38 mg / L, with the total nitrogen removal rate increasing by 7.8–32.2%, and the total phosphorus concentration decreased to 2.9 mg / L, with the total phosphorus removal rate increasing by 4.0–52.0%. The effluent met the GB16171-2012 indirect discharge standard (chemical oxygen demand COD < 150 mg / L, total nitrogen TN < 50 mg / L, total phosphorus TP < 3.0 mg / L) (Table 3).

[0046] Table 3. Effects of different concentrations of plant hormones on the biological treatment of coking wastewater by activated sludge.

[0047]

[0048] Example 4

[0049] The coking wastewater was taken from a coking plant, with a salinity of 4.55%, COD concentration of 600 mg / L, total nitrogen concentration of 90 mg / L, and total phosphorus concentration of 10 mg / L. In a microalgae (Phaeodactylum tricornutum, purchased from Shanghai Guangyu Biotechnology Co., Ltd.) system for treating high-salinity wastewater, 1, 10, and 100 μmol / L of 6-benzylaminopurine, p-hydroxybenzoic acid, and naphthaleneacetic acid were added to the aerobic biological treatment unit of a conventional bioreactor. The microalgae biomass was 0.749 g / L, the stirring speed was 150 rpm, and the temperature was room temperature. After 48 hours of reaction, the microalgae biomass increased by 14.6–56.8%, and the effluent COD concentration decreased to 148 mg / L. Compared with Comparative Example 4, the COD degradation rate increased by 16.2–57.7%. Meanwhile, the total nitrogen concentration in the effluent decreased to 44 mg / L, with the total nitrogen removal rate increasing by 10.0–34.4%, and the total phosphorus concentration decreased to 4.1 mg / L, with the total phosphorus removal rate increasing by 4.0–43.0%. Furthermore, the microalgal oil content reached as high as 25.8%, with a final oil yield of 0.267 g / L, representing increases of 3.5–14.5% and 22.5–95.0%, respectively, compared to Comparative Example 4 (Table 4).

[0050] Table 4. Effects of different concentrations of plant hormones on the biological treatment of coking wastewater by activated sludge.

[0051]

[0052] The experimental results of Examples 3 and 4 showed that 100 μmol / L 6-benzylaminopurine had the best enhancing effect on the biological treatment of coking wastewater. After adding 100 μmol / L 6-benzylaminopurine, the respiration rate of activated sludge and microalgae biomass increased by 24.5% and 56.8%, respectively. Furthermore, in terms of effluent quality, activated sludge was slightly more effective than microalgae. Compared with the conventional biological treatment group, the biological treatment group with added plant hormones achieved an effluent COD concentration as low as 117 mg / L, with a COD degradation rate increased by 32.0%. Simultaneously, the effluent total nitrogen and total phosphorus concentrations were reduced to 38 mg / L and 2.9 mg / L, respectively, with removal rates increased by 32.2% and 52.0%, respectively. The effluent met the GB16171-2012 indirect discharge standard (Chemical Oxygen Demand (COD) < 150 mg / L, Total Nitrogen (TN) < 50 mg / L, Total Phosphorus (TP) < 3.0 mg / L). In addition, the use of microalgae to treat coking wastewater resulted in an oil content of 25.8% and an oil yield of 0.267 g / L compared to Comparative Example 4, representing increases of 14.5% and 95.0%, respectively.

[0053] Comparative Example 1

[0054] Pharmaceutical wastewater was taken from a raw material drug manufacturing plant, with a salinity of 3.75%, COD concentration of 800 mg / L, total nitrogen concentration of 80 mg / L, and total phosphorus concentration of 8 mg / L. When treating the high-salinity pharmaceutical wastewater with activated sludge, a conventional bioreactor was used with a sludge concentration of 4 g / L, a stirring speed of 150 rpm, and room temperature. After 48 hours of reaction, the activity of the activated sludge, characterized by the respiration rate, was 15.2 mg / (L·h). The effluent COD concentration was 460 mg / L, with a COD degradation rate of 42.5%; the effluent total nitrogen concentration was 64 mg / L, with a total nitrogen removal rate of 20.0%; and the effluent total phosphorus concentration was 6.3 mg / L, with a total phosphorus removal rate of 21.3%.

[0055] Comparative Example 2

[0056] The pharmaceutical wastewater was taken from a raw material drug manufacturing plant, with a salinity of 3.75%, COD concentration of 800 mg / L, total nitrogen concentration of 80 mg / L, and total phosphorus concentration of 8 mg / L. Microalgae (Phaeodactylum tricornutum, purchased from Shanghai Guangyu Biotechnology Co., Ltd.) were used as the functional biological treatment for the pharmaceutical wastewater in a conventional bioreactor with a microalgae concentration of 0.5 g / L. The stirring speed was 150 rpm, the temperature was room temperature, and after 48 hours of reaction, the microalgae biomass was 0.803 g / L, the COD concentration in the wastewater was 551 mg / L (COD degradation rate of 31.1%), the effluent total nitrogen concentration was 73 mg / L (total nitrogen removal rate of 8.8%), the effluent total phosphorus concentration was 7.2 mg / L (total phosphorus removal rate of 10.0%), the microalgae oil content was 22.5%, and the oil yield was 0.181 g / L.

[0057] Comparative Example 3

[0058] The coking wastewater was taken from a coking plant, with a salinity of 4.55%, a COD concentration of 600 mg / L, a total nitrogen concentration of 90 mg / L, and a total phosphorus concentration of 10 mg / L. When treating the high-salinity coking wastewater with activated sludge, a conventional bioreactor was used. The sludge concentration was 4 g / L, the stirring speed was 150 rpm, and the temperature was room temperature. After 48 hours of reaction, the activity of the activated sludge, characterized by the respiration rate, was 15.1 mg / (L·h). The effluent COD concentration was 309 mg / L, with a COD degradation rate of 48.5%. The effluent total nitrogen concentration was 67 mg / L, with a total nitrogen removal rate of 25.6%. The effluent total phosphorus concentration was 8.1 mg / L, with a total phosphorus removal rate of 19.0%.

[0059] Comparative Example 4

[0060] Coking wastewater, sourced from a coking plant, had a salinity of 4.55%, a COD concentration of 600 mg / L, a total nitrogen concentration of 90 mg / L, and a total phosphorus concentration of 10 mg / L. Microalgae (Phaeodactylum tricornutum, purchased from Shanghai Guangyu Biotechnology Co., Ltd.) were used as the functional biological treatment for the coking wastewater in a conventional bioreactor with a microalgae concentration of 0.5 g / L. The stirring speed was 150 rpm, the temperature was room temperature, and after 48 hours of reaction, the microalgae biomass was 0.749 g / L, the COD concentration in the wastewater was 494 mg / L (COD degradation rate 17.7%), the effluent total nitrogen concentration was 75 mg / L (total nitrogen removal rate 16.7%), the effluent total phosphorus concentration was 8.4 mg / L (total phosphorus removal rate 16.0%), the microalgae oil content was 22.9%, and the oil yield was 0.172 g / L.

[0061] In addition, the plant hormones mentioned above also have a significant promoting effect on other salt-tolerant microalgae, such as the domesticated Chlorella regularis FACHB-729 (purchased from the Freshwater Algae Seed Bank of the Chinese Academy of Sciences), indicating that plant hormones have universal applicability in promoting the treatment of high-salt wastewater by salt-tolerant microalgae.

[0062] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention and not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for enhancing the biological treatment of high-salt organic wastewater using plant hormones, characterized in that, Includes the following steps: Plant hormones were added during the aerobic reaction treatment of high-salt organic wastewater. The plant hormone is 6-benzylaminopurine; The salinity of the high-salt organic wastewater is 4.55%; the high-salt organic wastewater is coking wastewater containing phenolic pollutants; The concentration of the plant hormone in high-salt organic wastewater is 1~100 μmol / L; The aerobic reaction treatment was carried out at room temperature; the aerobic reaction treatment time was 24-48 hours. The microorganisms used in the aerobic reaction treatment are activated sludge; the activated sludge is activated sludge from a high-salt organic wastewater biological treatment unit or activated sludge from a municipal sewage biological treatment unit. The concentration of the activated sludge in the high-salt organic wastewater is 3~5 g / L.

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