A sodium benzoate degradation composite agent, a preparation method thereof and application thereof in sodium benzoate wastewater treatment

Abstract

This invention discloses a sodium benzoate degradation composite agent, comprising a green algae TDX16-DE seed culture and a bacterial TD18 seed culture, wherein the cell concentrations of the green algae TDX16-DE seed culture and the bacterial TD18 seed culture are 2×10⁻⁶ and 2×10⁻⁶, respectively. 7 cells·mL ‑1 and 1×10 8 cells·mL ‑1 In application, the green algae TDX16-DE seed culture and the bacterial TD18 seed culture were inoculated into wastewater containing sodium benzoate, nitrate nitrogen, and phosphorus at a volume ratio of 1:0.2:10, and cultured for 10-12 days at room temperature and a light intensity of 60 μmol / (m²·s). This method is suitable for wastewater with sodium benzoate concentrations of 4000-9000 mg·L⁻¹. ‑1 The removal rate of sodium benzoate was 4.13%–100%, and the peak removal rate was 63.84–774.47 mg·(L·d). ‑1 This composite agent is resistant to sodium benzoate and can synergistically and efficiently remove sodium benzoate, nitrogen, and phosphorus from wastewater. It has good wastewater treatment effect, the degradation process is green and sustainable, and the cost is low, making it suitable for the preparation of wastewater treatment products.

Description

Technical Field

[0001] This invention relates to a method for treating wastewater using microorganisms, specifically to a sodium benzoate degradation composite agent and its application in the treatment of sodium benzoate wastewater. Background Technology

[0002] Sodium benzoate is a chemically synthesized additive widely used in food processing, pharmaceutical manufacturing, and other industries. Its production and use generate large amounts of sodium benzoate-containing wastewater. This wastewater has a high concentration of organic matter and poor biodegradability. Improper treatment can easily lead to the accumulation of sodium benzoate, which can not only damage local aquatic ecosystems but also, in severe cases, threaten human health. Therefore, finding a comprehensive treatment technology for sodium benzoate wastewater that suits China's national conditions is of great significance for environmental protection.

[0003] Traditional methods for treating sodium benzoate wastewater include physical, chemical, and biological methods. Physical methods include adsorption and extraction. Chemical methods include ozone oxidation, ultraviolet / hydrogen peroxide treatment, Fenton oxidation, and photocatalysis. Biological methods primarily utilize microalgae or other microorganisms (bacteria, fungi, etc.) to oxidize, degrade, and adsorb organic pollutants in wastewater, using these substances as nutrients while purifying the wastewater. The materials (such as extractants) and chemical reagents used in physical and chemical methods for treating sodium benzoate wastewater are expensive, and the process may cause secondary pollution to the environment.

[0004] Currently, there is a need to develop a green, sustainable, and simple method for treating sodium benzoate wastewater. Summary of the Invention

[0005] In view of the above-mentioned prior art, the present invention provides a sodium benzoate degradation composite agent and its application in the treatment of sodium benzoate wastewater. The present invention utilizes a biological method to treat sodium benzoate wastewater, which is simple to operate and environmentally friendly.

[0006] To address the aforementioned technical problems, this invention proposes a sodium benzoate degradation composite agent, comprising *Chlorella tinctoria* (green algae TDX16-DE) seed culture and *Gordonella terrestris* (bacterial TD18) seed culture, wherein the cell concentration of the *Chlorella tinctoria* TDX16-DE seed culture is 2 × 10⁻⁶. 7 cells·mL -1 The cell concentration of the bacterial TD18 seed culture was 1×10⁻⁶. 8 cells·mL -1 .

[0007] The preparation method of the above-mentioned sodium benzoate degradation composite agent includes the preparation of green algae TDX16-DE seed culture and bacterial TD18 seed culture; wherein:

[0008] Preparation of green algae TDX16-DE seed culture: After obtaining the green algae TDX16-DE culture medium, it was inoculated into sterile BBM medium. After incubation in a light incubator, the cells were collected by centrifugation and diluted with sterile BBM medium to obtain a cell concentration of 2×10⁻⁶. 7 cells·mL -1 Green algae TDX16-DE seed culture;

[0009] Preparation of bacterial TD18 seed culture: Refrigerated bacterial TD18 was streaked onto solid LB medium and activated by incubation. The activated bacterial TD18 was then transferred to liquid LB medium and fermented in a light-controlled, temperature-controlled shaker to obtain the bacterial fermentation broth. The broth was centrifuged, cells were collected, and diluted with sterile BBM medium to obtain a cell concentration of 1×10⁻⁶. 8 cells·mL -1 TD18 bacterial seed culture.

[0010] The sodium benzoate degradation composite agent prepared according to this invention is used for the treatment of wastewater containing sodium benzoate, nitrate nitrogen, and phosphorus. In the sodium benzoate wastewater treatment, the sodium benzoate degradation composite agent prepared by the method described in claim 2 is inoculated into wastewater containing sodium benzoate, nitrate nitrogen, and phosphorus, and cultured for 10-12 days at room temperature and a light intensity of 60 μmol / (m²·s).

[0011] The concentration of sodium benzoate in the wastewater is 4000~9000 mg·L. -1 The *TDX16-DE* seed culture of *Chlorophytum comosum* and the *TD18* seed culture of *Bacteria TD18* were inoculated into the wastewater at a volume ratio of 1:0.2:10. The cell count ratio of *TDX16-DE* to *TD18* was 10:7. The removal rate of sodium benzoate was 4.13%–100%, with a peak removal rate of 63.84–774.47 mg·(L·d). -1 .

[0012] Compared with the prior art, the beneficial effects of the present invention are:

[0013] This invention provides a composite microbial agent containing algae and bacteria that can treat sodium benzoate. Under optimal inoculation ratio, it can effectively remove sodium benzoate, total nitrogen, and total phosphorus. When applied to the treatment of sodium benzoate wastewater, this composite microbial agent has good treatment effect, strong adaptability, simple cultivation method, green and sustainable degradation process, and low cost, making it suitable for the preparation of wastewater treatment products. Attached Figure Description

[0014] Figure 1The study measured the removal rate of sodium benzoate from wastewater of different concentrations by culturing the green algae TDX16-DE seed culture in wastewater alone.

[0015] Figure 2 The study measured the removal rate of sodium benzoate from wastewater of different concentrations by culturing the TD18 bacterial seed culture in wastewater alone.

[0016] Figure 3 The seed culture of green algae TDX16-DE and bacterial seed culture TD18 were inoculated into wastewater at different ratios to achieve a concentration of 3000 mg·L⁻¹. -1 Sodium benzoate removal rate in sodium benzoate wastewater.

[0017] Figure 4 The seed culture of green algae TDX16-DE and bacterial seed culture TD18 were inoculated into wastewater at different ratios to achieve a concentration of 3000 mg·L⁻¹. -1 Changes in the removal rate of sodium benzoate from sodium benzoate wastewater.

[0018] Figure 5 This involves inoculating green algae TDX16-DE seed culture and bacterial TD18 seed culture in wastewater at the optimal inoculation ratio to treat high concentrations (4000~9000 mg·L⁻¹). -1 The removal rate of sodium benzoate in sodium benzoate wastewater.

[0019] Figure 6 This involves inoculating green algae TDX16-DE seed culture and bacterial TD18 seed culture in wastewater at the optimal inoculation ratio to treat high concentrations (4000~9000 mg·L⁻¹). -1 Changes in the removal rate of sodium benzoate in sodium benzoate wastewater.

[0020] Figure 7 This involves inoculating green algae TDX16-DE seed culture and bacterial TD18 seed culture in wastewater at the optimal inoculation ratio to treat high concentrations (4000~9000 mg·L⁻¹). -1 Changes in the concentration of nitrate nitrogen in sodium benzoate wastewater.

[0021] Figure 8 This involves inoculating green algae TDX16-DE seed culture and bacterial TD18 seed culture in wastewater at the optimal inoculation ratio to treat high concentrations (4000~9000 mg·L⁻¹). -1 Changes in total phosphorus concentration in sodium benzoate wastewater. Detailed Implementation

[0022] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but the following embodiments are by no means intended to limit the present invention.

[0023] The culture media used in the following examples were prepared as follows:

[0024] BBM (Bold's Basal Medium) medium, with the following components added to every 1L of distilled water: 250 mg NaNO3, 175 mg KH2PO4, 75 mg MgSO4·7H2O, 75 mg K2HPO4, 50 mg EDTA·Na2, 31 mg KOH, 25 mg NaCl, 25 mg CaCl2·2H2O, 11.4 mg H3BO3, 8.82 mg ZnSO4·7H2O, 1.44 mg MnCl2·4H2O, 1.79 mg Na2MoO4, 1.57 mg CuSO4·5H2O, 0.49 mg Co(NO3)2·6H2O, 4.98 mg FeSO4·7H2O, and 1 mL H2SO4.

[0025] LB (Luria-Bertani) medium comes in two forms: solid LB medium and liquid LB medium. Solid LB medium is prepared by adding the following ingredients to every 1 L of distilled water: 5 g yeast extract, 10 g peptone, 10 g NaCl, and 18 g agar. Liquid LB medium, unlike solid LB medium, does not require the addition of agar.

[0026] Example 1

[0027] Preparation of sodium benzoate degradation compound and sodium benzoate wastewater, and detection method of sodium benzoate.

[0028] (1) Preparation of Green Algae TDX16-DE Seed Culture: Inoculate 10 mL of Green Algae TDX16-DE sterile culture medium into an Erlenmeyer flask containing 100 mL of sterile BBM medium. Incubate in a light incubator at 25 ℃ and a light intensity of 60 μmol / (m²·s), and manually shake twice daily. Once the algal cells have stabilized, transfer 5 mL of the algal culture to a 10 mL centrifuge tube and centrifuge at 8000 r·min. -1 Centrifuge for 10 min under controlled conditions, discard the supernatant, collect the algal cells, and wash and dilute them with sterile 1.5N-BBM medium. Count the cells under a microscope using a hemocytometer and adjust the cell concentration to 2×10⁻⁶. 7 cells·mL -1 For use in subsequent experiments.

[0029] (2) Preparation of bacterial TD18 seed culture: Bacterial TD18 was picked from the surface of slant agar medium stored at 4 ℃ and streaked onto LB solid medium plates. The plates were then incubated at 25 ℃ for 48 h to activate the bacterial strain. Subsequently, an appropriate amount of activated bacteria was scraped off with an inoculation loop and transferred to 100 mL of liquid LB medium. The medium was then incubated at 25 ℃ and 150 r·min. -1 The culture was incubated under shaking conditions for 24 h. After incubation, 5 mL of the culture medium was transferred to a 10 mL centrifuge tube and centrifuged at 12,000 r·min. -1 Centrifuge for 10 min, discard the supernatant, collect the bacterial cells, wash and resuspend them in sterile 1.5N-BBM medium, and dilute appropriately to obtain a cell concentration of 1×10⁻⁶. 8 cells·mL -1 TD18 bacterial seed culture.

[0030] (3) Preparation of simulated wastewater containing sodium benzoate in the laboratory: Take 1 g of sodium benzoate, add it to BBM medium, make up to 100 mL in a volumetric flask, sterilize, and obtain 10 g·L -1 The sodium benzoate stock solution was prepared. The concentration of sodium benzoate was determined by using sodium benzoate as the solute and BBM medium as the solvent to prepare a solution with a mass concentration of 1 g·L⁻¹. -1 Sodium benzoate solutions were analyzed across the entire wavelength range of 220–650 nm, and the optimal absorption wavelength for alkaline sodium benzoate was determined to be 224 nm. Concentrations of 0.0, 2.0, 4.0, 6.0, 8.0, and 10.0 mg·L⁻¹ were prepared. -1 A series of sodium benzoate standard solutions were used, and the absorbance of the standard solutions at 224 nm was measured. A standard curve was plotted with sodium benzoate concentration (x) on the x-axis and absorbance (Y) on the y-axis. The regression equation obtained after fitting was: Y = 0.05323x + 0.01019, (R² = 0.05323x + 0.01019). 2 = 0.998).

[0031] (4) In this invention, the green algae TDX16-DE seed solution and the bacterial TD18 seed solution (with the same number of cells in both) are inoculated into sodium benzoate wastewater of different concentrations to obtain culture solution. 5 mL of the culture solution is centrifuged, 1 mL of supernatant is taken, and the supernatant is diluted to make its concentration within the measurable range. The absorbance of the diluted supernatant at 224 nm is measured, and the mass concentration of sodium benzoate is obtained by regression equation of sodium benzoate standard curve.

[0032] Example 2

[0033] The effects of separately culturing the green algae TDX16-DE seed culture and the bacterial TD18 seed culture prepared in Example 1 on the treatment of sodium benzoate wastewater of different concentrations.

[0034] Seven samples A0-A6 were prepared: 100 mL of sodium benzoate was placed in each of seven 250 mL Erlenmeyer flasks, each containing 0 mg·L⁻¹ sodium benzoate. -1 1000 mg·L -1 1200 mg·L -1 1400 mg·L -1 1600 mg·L -1 1800 mg·L -1 2000 mg·L -1 Wastewater. 10 mL of the green algae TDX16-DE seed culture prepared in Example 1 was inoculated into each of the above six conical flasks. The samples were sequentially labeled as Sample A0, Sample A1, Sample A2, Sample A3, Sample A4, Sample A5, and Sample A6, as shown in Table 1.

[0035] Seven samples, B0-B6, were prepared: 100 mL of sodium benzoate was placed in each of seven 250 mL Erlenmeyer flasks, each containing 0 mg·L⁻¹ sodium benzoate. -1 1000 mg·L -1 2000 mg·L -1 3000 mg·L -1 4000 mg·L -1 5000 mg·L -1 6000 mg·L -1 Wastewater. To each of the seven conical flasks, 2 mL of the bacterial seed solution TD18 prepared in Example 1 was inoculated, with the cell count matching that of Sample A. The samples were sequentially designated as Sample B0, Sample B1, Sample B2, Sample B3, Sample B4, Sample B5, and Sample B6, as shown in Table 1.

[0036] The conical flasks containing samples A0-A6 and B0-B6 were placed in a light incubator (25 ℃, light intensity 60 μmol / (m²·s)) and incubated statically, with manual shaking twice daily. After 12 days of incubation, the sodium benzoate concentration (mg·L⁻¹) was measured. -1 ), and calculate the sodium benzoate removal rate (%) accordingly, N=(N0-N t ) / N0×100%, where N is the removal rate of sodium benzoate, in units of %; N0 and N t Sodium benzoate in solution on day t0 and day t1, respectively. n Mass concentration per day, mg·L -1 t0 is the first day of cultivation, t n It's the last day of training.

[0037] like Figure 1As shown in Table 1, the removal rates of sodium benzoate in samples A1 and A2, cultured alone with the TDX16-DE seed culture for 12 days, were calculated to be 100%. The removal rates of sodium benzoate in samples A3, A4, A5, and A6 were 82.56%, 62.53%, 40.34%, and 28.97%, respectively. Figure 2 As shown in Table 2, the removal rate of sodium benzoate from samples B1, B2, and B3 by bacterial seed culture alone for 12 days was 100%, while the removal rates for samples B4, B5, and B6 were 72.91%, 32.09%, and 24.01%, respectively. This indicates that both the green algae TDX16-DE and the bacteria TD18 can utilize their own metabolism to remove sodium benzoate from wastewater.

[0038] Table 1

[0039]

[0040] Table 2

[0041]

[0042] Example 3

[0043] The optimal inoculation ratio of the green algae TDX16-DE seed culture and the bacterial TD18 seed culture prepared in Example 1 was optimized when they were mixed and cultured in wastewater.

[0044] The tests in Example 2 revealed that the highest concentration of sodium benzoate removed by the bacterial TD18 seed culture was 3000 mg·L⁻¹. -1 Therefore, at a sodium benzoate concentration of 3000 mg·L⁻¹ -1 We conducted mixed culture of algae and bacteria to determine the optimal inoculation ratio of green algae TDX16-DE seed culture to bacterial TD18 seed culture.

[0045] Seven samples (C1-C5, CKC, and CKG) were prepared: 100 mL of sodium benzoate was placed in each of seven 250 mL Erlenmeyer flasks, with a concentration of 3000 mg·L⁻¹. -1 Wastewater.

[0046] 10 mL of green algae TDX16-DE and 0.8 mL, 1.0 mL, 1.2 mL, 1.4 mL and 1.6 mL of bacterial TD18 seed culture were respectively inoculated into the wastewater of the above five conical flasks and labeled as samples C1, C2, C3, C4 and C5. The cell ratio of green algae TDX16-DE to bacterial TD18 was 10:4, 10:5, 10:6, 10:7 and 10:8 respectively.

[0047] 10 mL of green algae TDX16-DE and 2.0 mL of bacterial TD18 seed culture were inoculated into the wastewater in the two conical flasks mentioned above, and were respectively labeled as sample CKC and CKG.

[0048] The seven inoculated samples were placed in a light incubator (25 ℃, light intensity 60 μmol / (m²·s)) and incubated statically, shaken manually twice daily. Each experiment was repeated in triplicate. After 12 days of incubation, the sodium benzoate concentration (mg·L⁻¹) was measured. -1 Based on this, the removal rate (%) and removal rate (mg·(L·d) of sodium benzoate were calculated. -1 The removal rate of sodium benzoate is calculated using the formula N = (N0 - N). t The formula for calculating the sodium benzoate removal rate is: R = (N0 - N) / N0 × 100%. t ) / (t n -t0), where R is the removal rate of sodium benzoate, mg·(L·d). -1 N0 and N t Sodium benzoate in solution on day t0 and day t1, respectively. n Mass concentration per day, mg·L -1 .

[0049] like Figure 3 , Figure 4 As shown in Table 3, the sodium benzoate removal rates and removal percentages of M10 / 4, M10 / 5, M10 / 6, M10 / 7, and M10 / 8 in the mixed culture system were all higher than those of CKC (16.76%, 63.00 mg·(L·d)). -1 The sodium benzoate removal rates of M10 / 6, M10 / 7, M10 / 8, and CKG can reach 100%, with M10 / 7 exhibiting the highest peak sodium benzoate removal rate at 647.16 mg·(L·d). -1 Secondly, M10 / 8 (559.56 mg / L / d) -1 M10 / 6 (546.56 mg / L) -1 ), CKG (544.89 mg·(L·d) -1 This indicates a synergistic effect between the green algae TDX16-DE and the bacteria TD18, and the optimal cell ratio for co-culturing green algae TDX16-DE and bacteria TD18 is 10:7, at which point the removal efficiency of sodium benzoate is the highest.

[0050] Table 3

[0051]

[0052] Example 4

[0053] Green algae TDX16-DE and bacteria TD18 were used to treat sodium benzoate in high-concentration sodium benzoate wastewater at the optimal inoculation ratio.

[0054] The experiment in Example 3 showed that the sodium benzoate removal effect was best when the green algae TDX16-DE and bacteria TD18 were inoculated at an optimal inoculation ratio of 10:7. Therefore, the green algae TDX16-DE and bacteria TD18 were inoculated at a cell number ratio of 10:7 into six 250 mL Erlenmeyer flasks, each containing 100 mL of high-concentration sodium benzoate wastewater, with a sodium benzoate concentration of 4000 mg·L⁻¹. -1 5000 mg·L -1 6000 mg·L -1 7000 mg·L -1 8000 mg·L -1 and 9000 mg·L -1 These were designated as samples M4000, M5000, M6000, M7000, M8000, and M9000, respectively. All six conical flasks used in the inoculation experiment were placed in a light incubator (25 ℃, light intensity 60 μmol / (m²·s)) and statically cultured, shaken manually twice daily. Each experiment was repeated in triplicate. After 12 days of culture, the sodium benzoate concentration (mg·L⁻¹) was measured. -1 Based on this, the sodium benzoate removal rate is calculated using the formula N=(N0-N t The formula for calculating the removal rate of sodium benzoate is R = (N0 - N) / N0×100%. t ) / (t n Calculate the sodium benzoate removal rate (%) and removal rate (mg·(L·d)) respectively. -1 ).

[0055] like Figure 5 and Figure 6 As shown, the removal rates of sodium benzoate in samples M4000, M5000, M6000, M7000, M8000, and M9000 were 100% (10 d), 55.22% (12 d), 32.29% (12 d), 17.30% (12 d), 6.47% (12 d), and 4.13% (12 d), respectively, with peak removal rates of 774.47 mg·(L·d). -1 468.78 mg / (L·d) -1 330.94 mg / L (d) -1 192.72 mg / L (d) -1 96.42 mg / L (d) -1 And 63.84 mg·(L·d) -1Compared to single-culture, co-culture of algae and bacteria at the optimal inoculum ratio further increases the maximum concentration of sodium benzoate that can be completely removed. Specifically, it can completely remove concentrations up to 4000 mg / L. -1 Sodium benzoate. This indicates that a mixed culture of green algae TDX16-DE and bacteria TD18 at a cell number ratio of 10:7 can treat wastewater with higher concentrations of sodium benzoate.

[0056] Example 5

[0057] Treatment of nitrate nitrogen in high-concentration sodium benzoate wastewater using green algae TDX16-DE and bacteria TD18 at the optimal inoculum ratio

[0058] Similar to Example 4, after 12 days of cultivation, the nitrate nitrogen concentration (mg·L⁻¹) in M4000, M5000, M6000, M7000, M8000, and M9000 was measured. -1 ).

[0059] like Figure 7 As shown, nitrate nitrogen in the M4000 and M5000 culture systems was completely removed on days 10 and 12. On day 12, the nitrate nitrogen content in the M6000, M7000, M8000, and M9000 culture systems was 9.02 mg·L⁻¹. -1 15.75 mg·L -1 16.81 mg·L -1 and 22.04 mg·L -1 This indicates that a mixed culture of green algae TDX16-DE and bacteria TD18 at a cell ratio of 10:7 can efficiently remove nitrate nitrogen from high-concentration sodium benzoate wastewater.

[0060] Example 6

[0061] Green algae TDX16-DE and bacteria TD18 treated total phosphorus in high-concentration sodium benzoate wastewater at the optimal inoculation ratio.

[0062] Similar to Example 4, after 12 days of cultivation, the total phosphorus concentration (mg·L⁻¹) in M4000, M5000, M6000, M7000, M8000, and M9000 was measured. -1 ).

[0063] like Figure 8 As shown, on day 12, the total phosphorus content in the M4000, M5000, M6000, M7000, M8000, and M9000 culture systems was 8.64 mg·L⁻¹. -1 16.93 mg·L -1 24.04 mg·L -1 28.85 mg·L -134.53 mg·L -1 and 39.94 mg·L -1 This indicates that a mixed culture of green algae TDX16-DE and bacteria TD18 at a cell number ratio of 10:7 can remove total phosphorus from wastewater with high concentrations of sodium benzoate.

[0064] Although the present invention has been described above in conjunction with the accompanying drawings, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are preferred application examples that demonstrate the core technical ideas of the present invention, and are merely illustrative and not restrictive. Those skilled in the art can make many improvements and changes under the guidance of the present invention without departing from the spirit of the present invention, and these all fall within the protection scope of the present invention.

Claims

1. A sodium benzoate degradation composite agent, characterized in that, The mixture includes *Chlorella ts.* seed culture and *Gordonella terrestris* seed culture, wherein the cell concentration of the *Chlorella ts.* seed culture is 2 × 10⁻⁶. 7 cells·mL -1 The cell concentration of the *Gordonella stolonifer* seed culture was 1 × 10⁻⁶. 8 cells·mL -1 .

2. A method for preparing the sodium benzoate degradation composite agent as described in claim 1, characterized in that, This includes the separate preparation of *Chlorella ts.* seed culture and *Goldenella terrestris* seed culture; wherein: Preparation of *Chlorella ts.* seed culture: After obtaining the *Chlorella ts.* culture medium, it was inoculated into sterile BBM medium. After incubation in a light incubator, the cells were collected by centrifugation and diluted with sterile BBM medium to obtain a cell concentration of 2 × 10⁻⁶. 7 cells·mL -1 Tianjin Chlorella seed culture, abbreviated as Chlorella TDX16-DE seed culture; Preparation of *Gordonia stolonifera* seed culture: Refrigerated *Gordonia stolonifera* was streaked onto solid LB medium and activated by incubation. The activated bacteria were then transferred to liquid LB medium and fermented in a light-controlled, temperature-controlled shaker to obtain the bacterial fermentation broth. The broth was centrifuged, cells were collected, and diluted with sterile BBM medium to obtain a cell concentration of 1 × 10⁻⁶. 8 cells·mL -1 The seed culture of *Gordonella spp.*, or simply TD18 seed culture.

3. The application of a sodium benzoate degradation composite agent in the treatment of sodium benzoate wastewater, characterized in that, The sodium benzoate degradation composite agent prepared by the method described in claim 2 was inoculated into wastewater containing sodium benzoate, nitrate nitrogen and phosphorus, and cultured for 10 to 12 days at room temperature and light intensity of 60 μmol / (m²·s).

4. The application of the sodium benzoate degradation composite agent according to claim 3 in the treatment of sodium benzoate wastewater, characterized in that, The concentration of sodium benzoate in the wastewater is 4000~9000 mg·L. -1 The green algae TDX16-DE seed solution and the bacterial TD18 seed solution were inoculated into the wastewater at a volume ratio of 1:0.2:

10.

5. The application of the sodium benzoate degradation composite agent according to claim 4 in papermaking wastewater treatment, characterized in that, The cell ratio of the green algae TDX16-DE to the bacterial TD18 was 10:

7.

6. The application of the sodium benzoate degradation composite agent according to claim 5 in papermaking wastewater treatment, characterized in that, The removal rate of sodium benzoate ranged from 4.13% to 100%, with peak removal rates ranging from 63.84 to 774.47 mg / (L·d). -1 .

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