Method for synergistically treating printing and dyeing wastewater based on chlorella sorokiniana and vibrio fluvialis

Abstract

The application discloses a method for treating printing and dyeing wastewater by using Chlorella sorokiniana and Vibrio fluvialis. 7 8 The method is to separate original Chlorella sorokiniana strains and Vibrio fluvialis strains from printing and dyeing wastewater, and then add Vibrio fluvialis bacterial liquid with a concentration of 2.3*10 7 8 ~2.3*10 8 ~2.3*10 8 ~2.3*10 8 ~2.3*10 8 ~2.3*10 8 ~2.3*10 8 ~2.3*10 8 ~2.3*10 8 ~2.3*10 8 ~2.3*10 8 ~2.3*10 8 ~2.3*10 8 ~2.3*10 8 ~2.3*10 8 ~2.3*10 8 ~2.3*10 8 ~2.3*10 8 ~2.3*10 8 ~2.3*10 8 ~2.3*10 8 ~2.3*10 8 ~2.3*10 8 ~2.3*10 8 ~2.3*10 8 ~2.3*10 8 ~2.3*10 8 ~2.3*10 8 ~2.3*10 8 ~2.3*10 8 ~2.3*10 8 ~2.3*10 8 ~2.3*10 8 ~2.3*10 8 ~2.3*10

Description

Technical Field

[0001] This invention belongs to the fields of dyeing and printing wastewater treatment technology and environmental protection technology, specifically involving a method for the synergistic treatment of dyeing and printing wastewater based on Sorokinella spp. and Vibrio fluvialis. Background Technology

[0002] Dyeing and printing factories use a large number of compounds, such as dyes, colorants, surfactants, and mercerizing agents. The discharge of dye wastewater into environmental water bodies causes significant harm. First, the dyes in the wastewater absorb light, reducing water transparency, causing oxygen depletion, and affecting aquatic life. Second, some dyes are synthetic dyes of aromatic amines, which are carcinogenic and mutagenic. Catalysts such as metal complex dyes, antimony glycolate, antimony acetate, and antimony trioxide contain heavy metals, which are easily soluble in water and pose a significant hazard. Therefore, direct discharge of untreated dyeing and printing wastewater into the environment will damage the environment and harm organisms. Treatment of dyeing and printing wastewater is essential to reduce its environmental harm. Currently, traditional methods for treating dyeing and printing wastewater mainly include physical methods (adsorption, membrane distillation, extraction), chemical methods (chemical coagulation, chemical oxidation, advanced oxidation), and biological methods (activated sludge, biofilm). While physical methods are highly efficient, they are energy-intensive and adsorbent separation is difficult. Chemical technologies offer advantages such as high cost-effectiveness, good results, and short treatment time. However, some chemical agents may be unsuitable for wastewater treatment and may even generate large amounts of chemical sludge, potentially causing secondary pollution. Therefore, while physical and chemical methods are less costly, they are less environmentally friendly, while biological methods are relatively more environmentally friendly and effective.

[0003] Microalgae are tiny algal communities that can only be identified under a microscope. They utilize photosynthesis to convert inorganic carbon into biomass and consume nutrients such as nitrates and phosphates. Microalgae not only grow rapidly and have short growth cycles, but also contain a large amount of organic matter. The lipids, proteins, and carbohydrates in microalgae can be converted into byproducts such as biogas and bioethanol. Wastewater contains a large amount of nutrients required for microalgae growth. Studies have shown that algae are an excellent solution for biological wastewater treatment, possessing unique advantages. Bacteria are also a very good biological material for wastewater treatment. In fact, bacteria and microalgae can be integrated, allowing them to synergistically treat wastewater by utilizing their respective advantages and mechanisms of action. Under light conditions, microalgae consume dissolved CO2 in the water through photosynthesis, producing O2, increasing the dissolved oxygen concentration in the water, and promoting bacterial metabolism and biodegradation. Meanwhile, bacteria decompose organic pollutants through respiration and a series of biochemical reactions, while simultaneously absorbing large amounts of phosphorus from the wastewater, achieving a removal effect. Therefore, the synergistic treatment of dyeing and printing wastewater by bacteria and algae has significant application value.

[0004] Although there are reports of co-treatment of wastewater by bacteria and algae, their application in dyeing and printing wastewater treatment is limited, and there are no literature or patent reports on isolating native algal strains and bacterial strains from actual dyeing and printing wastewater and applying them to actual wastewater treatment. The algal strains and bacterial strains innovatively isolated from dyeing and printing wastewater in this invention have better tolerance and treatment effects, and have very good application prospects. This invention uses *Chlorella sorokinense*, which was isolated using the authorized patent: A Method for Rapid Isolation of Anaerobic Microalgae (Authorization No.: CN101709267B). Summary of the Invention

[0005] The purpose of this invention is to overcome the problem of poor removal of chemical oxygen demand and total phosphorus in dyeing and printing wastewater in the prior art, and to provide a method for treating dyeing and printing wastewater by using Chlorella sorokinosa and Vibrio fluvialis in synergy, thus providing technical support for wastewater treatment.

[0006] The technical solution adopted in this invention is as follows:

[0007] Chlorella sorokiniana and Vibrio fluvialis were isolated and cultured from dyeing and printing wastewater.

[0008] Includes the following steps:

[0009] (1) Isolation and culture of Chlorella sorokinosa:

[0010] The dyeing and printing wastewater was spread on BG-11 solid culture medium. After 6-9 days, single algal colonies grew, and the Chlorella sorokiniana algal strain was obtained.

[0011] The Chlorella sorokinense strain was cultured in 200-500 mL of growth medium 1 under full light, with an illuminance of 5000-6000 Lux, at 25±1℃. After 7-10 days of culture, it was in the logarithmic growth phase, and the Chlorella sorokinense algal solution was obtained for later use.

[0012] (2) Culture of Vibrio fluvibrio:

[0013] Take the dyeing and printing wastewater and spread it on a bacterial solid culture medium. After 2-3 days, bacteria will grow. Pick out a single colony and transfer it to another plate. Repeat this operation 3-6 times until the Vibrio fluvialis strain is obtained.

[0014] One or more Vibrio fluvibrio strains were inoculated into 200-500 ml of growth medium 2 and placed in a shaker incubator. The culture was carried out at 37-39℃ and 150-200 rpm for 48-72 h to obtain Vibrio fluvibrio bacterial suspension for later use.

[0015] (3) Co-treatment of dyeing and printing wastewater by bacteria and algae:

[0016] Cultivation of bacteria / algae: First, add the Vibrio fluvialis bacterial solution obtained in step (2) to the dyeing wastewater for 20-26 hours, then add the Chlorella sorokinae algal solution obtained in step (2) to the dyeing wastewater treated with the above bacterial solution for a total of 8 days of wastewater treatment.

[0017] The concentrations of *Chlorella sorokinense* and *Vibrio rivubilis* were 2.3 × 10⁻⁶. 7 ~2.3×10 8 The algal solution contained Vibrio fluvialis cells / mL and Chlorella total chlorophyll of 7–8 mg / L.

[0018] Sorokinella and Vibrio fluvialis were added to the dyeing and printing wastewater for co-treatment. Preferably, the inoculation order of Sorokinella and Vibrio fluvialis was to inoculate the bacterial solution first and the algal solution the next day.

[0019] The inoculum size of Chlorella sorokinae and Vibrio fluvialis is 3-10% of the dyeing wastewater, with the preferred inoculum size being 5% of the dyeing wastewater.

[0020] The ratio of Chlorella sorokinosa to Vibrio fluvialis is 1:2 to 2:1, with a preferred ratio of 1:2.

[0021] The pH value of the dyeing and printing wastewater is 6.5-10.5, preferably 6.5.

[0022] The light intensity in the environment should be 4000-12000 Lux, preferably 8000 Lux.

[0023] This invention provides the application of the above method in removing dyes, chemical oxygen demand and phosphorus from dyeing and printing wastewater.

[0024] Growth medium 1 consists of 1.5-2.0 g sodium nitrate, 0.04-0.05 g dipotassium hydrogen phosphate, 0.075-0.08 g magnesium sulfate heptahydrate, 0.036-0.04 g calcium chloride dihydrate, 0.006-0.010 g ferric ammonium citrate, 0.006-0.010 g citric acid, 0.001-0.002 g EDTA, 0.02-0.03 g sodium carbonate, and 1-2 ml of trace element stock solution. Water is added to bring the volume to 1000 mL, and the mixture is autoclaved at 121-125°C for 15-20 minutes.

[0025] The formula for the trace element stock solution is as follows: H3BO3 2.86g / L; MnCl2·H2O 1.81g / L; ZnSO4·7H2O 0.222g / L; CuSO4·5H2O 0.079g / L; NaMoO4·2H2O 0.390g / L; Co(NO3)2·6H2O 0.0494g / L. Add water to a final volume of 1000mL and autoclave at 121-125℃ for 15-20min.

[0026] Growth medium 2 consists of 25-30g of meat extract peptone, diluted with water to a final volume of 1000mL, and autoclaved at 121℃ for 20min.

[0027] The dyeing wastewater in steps (1) and (2) is a mixture of wastewater generated by the pretreatment, dyeing, printing and finishing processes of cotton fabric production in the dyeing and printing plant.

[0028] The system utilizes native bacteria and microalgae isolated and purified from dyeing and printing wastewater to construct a synergistic treatment system. This system can efficiently treat dyeing and printing wastewater and reduce the concentration of dye molecules, chemical oxygen demand, and total phosphorus in the wastewater.

[0029] The beneficial effects of this invention are as follows:

[0030] This invention isolates native microalgae and bacterial strains from dyeing and printing wastewater, exhibiting better wastewater tolerance. Based on the principles and methods of microbial ecology, the bacteria and algae are rationally proportioned, and the order of addition and environmental light conditions are optimized to achieve symbiotic cooperation between the bacteria and algae without antagonism, resulting in rapid reproduction and large biomass. Compared with wastewater treatment using a single species, this method is more stable and effective, and can more efficiently remove dyes, chemical oxygen demand (COD), and phosphorus, achieving the goal of water purification. Furthermore, the microalgae produce high-value byproducts, which, if utilized, can reduce wastewater treatment costs. Attached Figure Description

[0031] Figure 1 The results of identification for Chlorella sorokinosa.

[0032] Figure 2 The results are for the identification of Vibrio fluvibrio.

[0033] Figure 3 Example 1 shows the effect of the bacteria-algae synergistic system in treating dyeing and printing wastewater, including (a) total chlorophyll content, (b) dye removal rate, (c) COD content and removal rate, and (d) TP content and removal rate.

[0034] Figure 4 The graph shows the changes in TP and COD removal rates and total chlorophyll content in dyeing and printing wastewater treated in Example 1, Comparative Example 1, and Comparative Example 2. Comparative Example 1 (J): Vibrio fluvialis group; Comparative Example 2 (Z): Chlorella group; Example 1 (JZ): Bacterial-algae synergistic group. Detailed Implementation

[0035] In a specific example, the dyeing wastewater of this invention is a mixed wastewater generated from the pretreatment, dyeing, printing and finishing processes of cotton-type fabrics produced by the dyeing and printing plant of Yuyue Home Textiles Co., Ltd. in Binzhou City, Shandong Province.

[0036] In a specific example, both *Chlorella sorokinica* and *Vibrio fluvialis* of the present invention were isolated from the mixed dyeing wastewater of the aforementioned manufacturers.

[0037] The following embodiments are further illustrations of the present invention, but not limitations thereof.

[0038] Example 1

[0039] 1. Isolation of Chlorella sorokinosa and Vibrio riverine

[0040] The dyeing and printing wastewater was spread on BG-11 solid culture medium. After a single algal colony grew, the Chlorella sorokiniana algal strain was obtained.

[0041] The dyeing and printing wastewater was spread on a bacterial solid culture medium. After the bacteria grew, a single colony was picked out and placed on another plate. This operation was repeated until a purified strain of Vibrio fluvialis was obtained.

[0042] 2. Cultivation of Chlorella sorokinosa and Vibrio riverine

[0043] The isolated Chlorella sorokinae was cultured in 200 mL of growth medium 1 under full light (illuminance 5000 Lux) at 25 ± 1 °C. After 7 days of culture, the Chlorella sorokinae algal solution was obtained.

[0044] The formula for growth medium 1 is as follows: 1.5g sodium nitrate, 0.04g dipotassium hydrogen phosphate, 0.075g magnesium sulfate heptahydrate, 0.036g calcium chloride dihydrate, 0.006g ferric ammonium citrate, 0.006g citric acid, 0.001g EDTA, 0.02g sodium carbonate, 1ml trace element stock solution, add water to make up to 1000mL, and autoclave at 121℃ for 15min. The formula for the trace element stock solution is as follows: H3BO3 2.86 g / L; MnCl2·H2O 1.81 g / L; ZnSO4·7H2O 0.222 g / L; CuSO4·5H2O 0.079 g / L; NaMoO4·2H2O 0.390 g / L; Co(NO3)2·6H2O 0.0494 g / L. Add water to a final volume of 1000 mL and autoclave at 121℃ for 15 min.

[0045] The isolated Vibrio fluvialis was inoculated into 200 ml of growth medium 2 and placed in a shaker incubator for 48–72 h at 37 °C and 150 rpm to obtain Vibrio fluvialis bacterial suspension.

[0046] The formula for growth medium 2 is as follows: 25g of meat extract peptone, add water to a final volume of 1000mL, and autoclave at 121℃ for 20min.

[0047] 3. Co-treatment of dyeing and printing wastewater by bacteria and algae

[0048] (1) The concentrations of the dyeing and printing wastewater are: ammonia nitrogen 32.69 mg / L, COD 2324 mg / L, TP 6.5 mg / L, and pH 6.5. The dyeing and printing wastewater is centrifuged at 8000 rpm / min for 20 min and then autoclaved at 121℃ for 20 min for later use.

[0049] (2) Take 2.3 × 10 8 Vibrio fluvialis bacterial solution was added to the dyeing wastewater at a concentration of 1 / mL. Then, 24 hours later, Chlorella sorokinense bacterial solution with a total chlorophyll concentration of 7.4 mg / L was added. The Vibrio fluvialis bacterial solution was added at 5% of the wastewater volume from step (1), with a bacterial-to-algae inoculation ratio of 1:2. A control group without added bacterial-to-algae solution was used. Three parallel groups were established for each group. The culture temperature was 25±1℃, and the light intensity was 8000 Lux. The inoculation order was: first, Vibrio fluvialis bacterial solution, then Chlorella sorokinense bacterial solution, and cultured for 8 days. Samples were taken to measure chemical oxygen demand (COD), total phosphorus, and ammonia nitrogen content. The COD removal rate and total phosphorus removal rate reached 73.23% and 87.31%, respectively. The decolorization rate reached a maximum of 35%, and the Chlorella biomass reached 25.49 mg / L. These results indicate that the synergistic effect of bacteria and algae not only significantly improves wastewater purification but also yields a large amount of biomass.

[0050] Example 2

[0051] 1. The isolation of *Chlorella sorokinense* and *Vibrio fluvialis* was the same as in Example 1.

[0052] 2. The cultivation of *Chlorella sorokinense* and *Vibrio fluvialis* was the same as in Example 1.

[0053] 3. Treatment of dyeing and printing wastewater: The treatment steps are similar to those in Example 1, except that the ratio of bacteria to algae is 2:1, otherwise they are exactly the same. After 8 days of treatment, samples were taken to measure the chemical oxygen demand (COD) and total phosphorus content. The COD removal rate was calculated to be 66%, the total phosphorus removal rate was 41.7%, and the Chlorella biomass was 7.83 mg / L.

[0054] Example 3

[0055] 1. The isolation of *Chlorella sorokinense* and *Vibrio fluvialis* was the same as in Example 1.

[0056] 2. The culture of *Chlorella sorokinense* and *Vibrio fluvialis* was the same as in Example 1.

[0057] 3. Treatment of dyeing and printing wastewater: The treatment steps are similar to those in Example 1, except that the pH of the dyeing and printing wastewater is 7.5, otherwise they are exactly the same. After 8 days of treatment, samples were taken to measure the chemical oxygen demand (COD) and total phosphorus content. The COD removal rate was calculated to be 76.9%, the total phosphorus removal rate was 80%, and the Chlorella biomass was 13.11 mg / L.

[0058] Example 4

[0059] 1. The isolation of *Chlorella sorokinense* and *Vibrio fluvialis* was the same as in Example 1.

[0060] 2. The culture of Chlorella sorokinosa and Vibrio fluvialis is the same as in Example 1. The culture steps are similar to those in Example 1, except that the light intensity of Chlorella sorokinosa is 4000 Lux. Everything else is exactly the same.

[0061] 3. Treatment of dyeing and printing wastewater: After 8 days of treatment, samples were taken to measure chemical oxygen demand (COD) and total phosphorus content. The COD removal rate was calculated to be 74.7%, the total phosphorus removal rate was 75.2%, and the Chlorella biomass was 16.0 mg / L.

[0062] Comparative Example 1

[0063] 1. The isolation and culture of Vibrio fluvibrio were the same as in Example 1.

[0064] 2. Treatment of dyeing and printing wastewater:

[0065] (1) The concentrations of the dyeing and printing wastewater are: ammonia nitrogen 32.69 mg / L, COD 2324 mg / L, TP 6.5 mg / L, and pH 6.5.

[0066] (2) Take 2.3 × 10 8 A bacterial culture of Vibrio fluvialis per mL was inoculated into the dyeing and printing wastewater at a volume of 5%. After 8 days of treatment, samples were taken to measure the chemical oxygen demand (COD) and total phosphorus content. The COD removal rate was calculated to be 5.9%, and the TP removal rate was 19.2%.

[0067] Comparative Example 2

[0068] 1. The isolation and culture of *Chlorella sorokinense* were the same as in Example 1.

[0069] 2. Treatment of dyeing and printing wastewater:

[0070] (1) The concentrations of the dyeing and printing wastewater are: ammonia nitrogen 32.69 mg / L, COD 2324 mg / L, TP 6.5 mg / L, pH 6.5.

[0071] (2) A *Chlorella vulgaris* culture with a total chlorophyll content of 7.4 mg / L was inoculated into the dyeing and printing wastewater at a volume of 5%. The culture temperature was 25 ± 1℃, the light intensity was 8000 Lux, and the treatment lasted for 8 days. Samples were taken to measure the chemical oxygen demand (COD) and total phosphorus content. The COD removal rate was calculated to be 9.8%, the total phosphorus removal rate was 13.3%, and the total chlorophyll content was 16.74 mg / L.

[0072] Comparative Example 3

[0073] 1. The isolation and culture of Shewanella from Lake Gilka were the same as in Example 1.

[0074] 2. The isolation and culture of *Chlorella sorokinense* were the same as in Example 1.

[0075] 3. Treatment of dyeing and printing wastewater: The treatment steps are similar to those in Example 1. After 8 days of treatment, samples were taken to measure the chemical oxygen demand (COD) and total phosphorus content. The COD removal rate was calculated to be 3.86%, the total phosphorus removal rate was 1.42%, and the Chlorella biomass was 2.87 mg / L.

[0076] Comparative Example 4

[0077] 1. The isolation and culture of Aeromonas hydrophila were the same as in Example 1.

[0078] 2. The isolation and culture of *Chlorella sorokinense* were the same as in Example 1.

[0079] 3. Treatment of dyeing and printing wastewater: The treatment steps are similar to those in Example 1. After 8 days of treatment, samples were taken to measure the chemical oxygen demand (COD) and total phosphorus content. The COD removal rate was calculated to be 7.79%, the total phosphorus removal rate was 0.87%, and the Chlorella biomass was 3.21 mg / L.

[0080] Comparative Example 5

[0081] 1. The isolation and culture of Vibrio fluvibrio were the same as in Example 1.

[0082] 2. The isolation and culture of *Chlorella sorokinense* were the same as in Example 1.

[0083] 3. Treatment of dyeing and printing wastewater: The treatment steps are similar to those in Example 1, except that algae are inoculated first, followed by bacterial inoculation 24 hours later; otherwise, the process is identical. Samples were taken after 8 days of treatment to measure chemical oxygen demand (COD) and total phosphorus content. The calculated COD removal rate was 29.1%, and the total phosphorus removal rate was 41%.

[0084] Comparative Example 6

[0085] 1. The isolation of *Chlorella sorokinense* and *Vibrio fluvialis* was the same as in Example 1.

[0086] 2. The culture of *Chlorella sorokinense* and *Vibrio fluvialis* was the same as in Example 1.

[0087] 3. Treatment of dyeing and printing wastewater: The treatment steps are similar to those in Example 1, except that *Vibrio hygroscopicus* bacterial solution is added to the dyeing and printing wastewater, followed by *Chlorella sorokinense* algal solution 12 hours later. Everything else is identical. Samples were taken after 8 days of treatment to measure chemical oxygen demand (COD) and total phosphorus content. The calculated COD removal rate was 50.33%, the total phosphorus removal rate was 62.99%, and the *Chlorella sorokinense* biomass was 18.55 mg / L.

[0088] Comparative Example 7

[0089] 1. The isolation of *Chlorella sorokinense* and *Vibrio fluvialis* was the same as in Example 1.

[0090] 2. The culture of *Chlorella sorokinense* and *Vibrio fluvialis* was the same as in Example 1.

[0091] 3. Treatment of dyeing and printing wastewater: The treatment steps are similar to those in Example 1, except that *Vibrio fluvialis* bacterial solution is added to the dyeing and printing wastewater, followed by *Chlorella sorokinense* algal solution 40 hours later. Everything else is identical. Samples were taken after 8 days of treatment to measure chemical oxygen demand (COD) and total phosphorus content. The calculated COD removal rate was 45.90%, the total phosphorus removal rate was 65.86%, and the *Chlorella* biomass was 20.04 mg / L.

[0092] Comparative Example 8

[0093] 1. The isolation and culture of Vibrio fluvialis and Chlorella sorokinosa were the same as in Example 1.

[0094] 2. Treatment of dyeing and printing wastewater:

[0095] (1) The concentrations of the dyeing and printing wastewater are: ammonia nitrogen 32.69 mg / L, COD 2324 mg / L, TP 6.5 mg / L, pH 10.77.

[0096] (2) The treatment process is the same as in Example 1, except that after 8 days of treatment, samples were taken to measure the chemical oxygen demand and total phosphorus content. The COD removal rate was calculated to be 21.44%, the TP removal rate was 19.36%, and the Chlorella biomass was 5.78 mg / L.

[0097] As can be seen from the above embodiments and comparative embodiments, the method of the present invention has a very good treatment effect on dyeing and printing wastewater. It should be noted that the above preferred embodiments should not be considered as limitations on the present invention, and the scope of protection of the present invention should be determined by the scope defined in the claims. For those skilled in the art, several improvements can be made without departing from the spirit and scope of the present invention, and these improvements should also be considered within the scope of protection of the present invention.

Claims

1. A species of Chlorella sorokinense ( Chlorella sorokiniana ) and Vibrio riverine ( Vibrio fluvialis A method for the combined treatment of dyeing and printing wastewater, characterized in that, The method comprises the following steps: (1) separation and culture of Chlorella sorokiniana: The printing and dyeing wastewater was coated on BG-11 solid culture medium, and after 6-9 days, single algal colonies were grown to obtain Chlorella sorokiniana (Chlorella sp. Chlorella sorokiniana ) strains; The Chlorella sorokiniana strain is cultured in 200-500 mL of growth medium 1 under full light with an intensity of 5000-6000 Lux at 25±1℃ for 7-10 days to obtain a logarithmic growth phase, and the Chlorella sorokiniana algae liquid is obtained and reserved; (2) culture of Vibrio fluvialis: The printing and dyeing wastewater was coated on a bacterial solid culture medium, and bacteria grew after 2-3 days. Single colonies were picked and inoculated on another plate, and the operation was repeated 3-6 times to obtain the Vibrio fluvialis strain. Vibrio fluvialis ) The Vibrio fluvialis strain is inoculated into 200-500 mL of growth medium 2 and cultured in a shaking incubator at 37-39℃ and a rotation speed of 150-200 rpm for 48-72 hours to obtain Vibrio fluvialis liquid, which is reserved; (3) treatment of printing and dyeing wastewater by bacteria and algae: The Vibrio fluvialis liquid obtained in step (2) is added to the printing and dyeing wastewater for 20-26 hours, and then the Chlorella sorokiniana algae liquid obtained in step (1) is added to the printing and dyeing wastewater treated by the Vibrio fluvialis liquid for 8 days.

2. The method of claim 1, wherein: The concentration of the Vibrio fluvialis liquid obtained in step (2) is 2.3×10 7 2.3×10 8 The total chlorophyll of the Chlorella sorokiniana liquid obtained in step (1) is 7-8 mg / L.

3. The method of claim 1, wherein: The amount of Vibrio fluvialis liquid added in step (3) is 3-10% of the printing and dyeing wastewater.

4. The method of claim 1, wherein: The volume ratio of Vibrio fluvialis liquid to Chlorella sorokiniana algae liquid in step (3) is 1:2 to 2:

1.

5. The method of claim 1, wherein: The pH of the printing and dyeing wastewater treated in step (3) is adjusted to 6.5-10.

5.

6. The method of claim 1, wherein: The light intensity of the external environment during the culture process of step (3) is 4000-12000 Lux.

7. The method of claim 1, wherein: The growth medium 1 comprises 1.5-2.0 g of sodium nitrate, 0.04-0.05 g of potassium phosphate dibasic, 0.075-0.08 g of magnesium sulfate heptahydrate, 0.036-0.04 g of calcium chloride dihydrate, 0.006-0.010 g of ferric ammonium citrate, 0.006-0.010 g of citric acid, 0.001-0.002 g of EDTA, 0.02-0.03 g of sodium carbonate, and 1-2 mL of trace element mother liquor, and the volume is adjusted to 1000 mL with water, and the mixture is autoclaved at 121-125℃ for 15-20 min. The trace element mother liquor comprises 2.86 g / L of H3BO3, 1.81 g / L of MnCl2·H2O, 0.222 g / L of ZnSO4·7 H2O, 0.079 g / L of CuSO4·5 H2O, 0.390 g / L of NaMoO4·2 H2O, and 0.0494 g / L of Co(NO3)2·6 H2O, and the volume is adjusted to 1000 mL with water, and the mixture is autoclaved at 121-125℃ for 15-20 min.

8. The method of claim 1, wherein: The growth medium 2 is meat extract peptone 25-30 g, add water to 1000 mL, 121 ℃ high pressure sterilization 20 min.

9. The method of claim 1, wherein: The printing and dyeing wastewater in step (1) and step (2) is mixed wastewater generated in the pretreatment, dyeing, printing and finishing processes of cotton fabric production in the printing and dyeing plant.

Images