A method for treating organic wastewater containing FSI - ​

Abstract

The application provides a kind of FSI ‑ The application discloses a method for treating anionic wastewater, and belongs to the technical field of wastewater treatment. The method comprises the following steps: providing an integrated biological reactor, which comprises an anaerobic tank, an anoxic tank, an aerobic tank and a sedimentation tank in sequence along the direction of wastewater flow; the anaerobic tank is provided with a wastewater inlet, and the upper part of the sedimentation tank is provided with a supernatant outlet. After the wastewater passes through the anaerobic tank and the anoxic tank, effective FSI ‑ removal of anions, and the treated wastewater supernatant is discharged from the supernatant outlet arranged at the upper part of the sedimentation tank. The application utilizes microorganisms to degrade FSI ‑ anions in wastewater, and does not need to use or generate a large amount of chemical agents, thereby reducing the pollution to the environment and the use of chemical substances, and achieving efficient and relatively low-cost wastewater treatment.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, specifically to a wastewater treatment system containing FSI. - Methods for treating organic wastewater. Background Technology

[0002] Lithium bis(fluorosulfonyl)imide (LiFSI) has shown broad application prospects as a novel electrolyte lithium salt. Its high stability, excellent low-temperature performance, and hydrolytic stability make it an ideal alternative to traditional lithium salts (such as lithium hexafluorophosphate, LiPF6). LiFSI can be widely used in lithium-ion batteries, lithium-sulfur batteries, lithium-air batteries, and plays an important role in energy storage devices such as capacitors and supercapacitors. However, the industrial production process of LiFSI suffers from high energy consumption and environmental pollution. This includes wastewater containing LiFSI generated during production, such as from cleaning LiFSI filter residue, production equipment, and packaging containers, as well as FSI-containing wastewater generated during the recycling and dismantling of waste lithium batteries. - Anionic wastewater all contain FSI - Anions and organic matter cause foaming, which may be directly discharged into wastewater treatment plants, leading to excessive levels of LAS (anionic surfactants; Class I water quality requires LAS content to be below 0.5 ppm), causing serious environmental pollution. Currently, there are few effective treatment methods for this type of wastewater. Therefore, new solutions are needed to achieve sustainable development and environmental protection in LiFSI production. There are currently few reports on effective treatment methods for wastewater from LiFSI production.

[0003] Chinese patent document CN115818858A discloses a method for treating LiFSI wastewater, comprising the following steps: Adsorption: Using resin to adsorb LiFSI wastewater to obtain resin adsorbed with LiFSI. Desorption: Washing the resin adsorbed with LiFSI with alkaline solution to obtain LiFSI desorption solution. Concentration: Heating and concentrating the LiFSI desorption solution to obtain a lithium-containing concentrate. Neutralization: Adding acid to the lithium-containing concentrate for neutralization treatment to obtain a neutralized solution. Lithium precipitation: Adding carbonate or carbon dioxide to the neutralized solution for reaction to obtain carbonate precipitate. This method solves the problem of the inability to decompose large quantities of LiFSI in existing wastewater treatment processes, achieving full recovery and utilization of lithium resources, and is more environmentally friendly and economically efficient.

[0004] Chinese patent document CN 116119766 A discloses a method for efficiently treating LiFSI production wastewater. Under ambient temperature conditions, a quaternary ammonium salt compound is added to the wastewater to form a stable complex with the FSI- ions. An organic extractant is then used to extract the solution, removing the complex. Finally, the extracted organic phase is simply separated to recover the extractant. After this treatment, the removal rate of FSI- ions in the wastewater can reach over 98%, meeting emission standards. This method utilizes the properties of the complex and, through simple subsequent operations, avoids complex and lengthy process routes, effectively reducing environmental pollution and facilitating industrialization. This provides a new process route for the green synthesis and waste treatment of LiFSI.

[0005] The aforementioned existing technologies primarily employ physicochemical methods to treat LiFSI production wastewater. However, due to high costs and complex processes, they present certain limitations and challenges. Furthermore, since LiFSI production wastewater typically contains organic matter, the presence of which can also affect the efficiency of the extraction method. For example, if the mixture contains too many types of organic matter or organic matter with similar properties, the separation effect during extraction may be poor. Additionally, some organic matter may possess specific chemical properties, such as forming complexes or reacting with the solvent, which can also affect the extraction effect. Moreover, in practical applications, this treatment method can lead to high operating costs and requires complex operating procedures and equipment, limiting its widespread application in industrial production. Therefore, there is a need to seek more economical, efficient, and simple wastewater treatment solutions to improve treatment efficiency, reduce costs, and achieve sustainable resource utilization. Summary of the Invention

[0006] This invention provides a product containing FSI - The method for treating organic wastewater, and the designed device are capable of treating wastewater containing FSI. - It effectively degrades organic wastewater, with good reaction efficiency and removal effect.

[0007] The specific technical solution adopted is as follows:

[0008] This invention proposes a method for using FSI - Biological methods for treating organic wastewater include:

[0009] 1) Activated sludge is separately injected into anaerobic, anoxic, and aerobic tanks for acclimatization. During the acclimatization process, the anaerobic, anoxic, and aerobic tanks operate independently, maintaining dissolved oxygen levels of 0-0.5 mg / L, 0.5-1.5 mg / L, and 2-4 mg / L in the anaerobic, anoxic, and aerobic tanks, respectively. The acclimatization process is divided into several cycles, wherein the anaerobic tank utilizes FSI-containing...- The anaerobic tank was acclimated to the ionic compounds. Sodium nitrate was used for acclimation in the anoxic tank, and ammonium chloride was used for acclimation in the aerobic tank. After all acclimation was completed, the anaerobic tank, anoxic tank and aerobic tank were coupled in sequence.

[0010] 2) Passing through FSI - The organic wastewater first enters the anaerobic tank, where it comes into contact with and mixes with the activated sludge for biochemical degradation. The FSI in the wastewater... - As the sole source of nutrients N and S, it is initially absorbed and degraded by anaerobic microorganisms and used for their own cellular metabolic activities.

[0011] 3) The wastewater treated in the anaerobic tank enters the anoxic tank for further degradation and removal of organic matter;

[0012] 4) After being treated in the anoxic tank, the wastewater enters the aerobic tank, where the ammonia nitrogen in the wastewater undergoes nitrification.

[0013] 5) The wastewater treated in the aerobic tank is discharged into the aerobic tank for mud-water separation, and the separated liquid is discharged.

[0014] Preferably, in step 1), the acclimatization process in the anaerobic tank specifically involves:

[0015] S1: First, add nutrients to the anaerobic tank to enrich the microorganisms;

[0016] S2: After the microorganisms have completed enrichment, continue to add nutrients and FSI-containing substances to the anaerobic tank. - The compound was used to acclimatize the microorganisms in the anaerobic tank, and the content of FSI in the effluent was tested regularly. - The content of the compound, when two consecutive FSI contents - Once the content of the compound changes to less than the preset value, the acclimatization of the current cycle is completed.

[0017] S3: Subsequent cycles gradually increase the inclusion of FSI - The amount of compound added is adjusted, and step S2 is repeated; until FSI is achieved. - The amount of compound added and the amount of FSI-containing compound to be treated - FSI in organic wastewater - When the content of the microorganisms is equal and the acclimatization of the microorganisms at that dosage is completed, the acclimatization process of the entire anaerobic tank is finished.

[0018] More preferably, the FSI-containing component added in the first cycle - The concentration of the compound in the anaerobic feed is the concentration of the FSI-containing compound to be treated. - FSI in organic wastewater - The concentration was 20%; in subsequent cycles, the concentration of FSI was increased by a gradient of 10%-20%. -The amount of the compound added.

[0019] Preferably, the acclimatization process in the anoxic pool specifically includes:

[0020] Nutrients were added to the anoxic tank. After microorganisms accumulated, nutrients and sodium nitrate were continuously added to the anoxic tank to acclimate the microorganisms. The concentration of sodium nitrate was adjusted according to the concentration of FSI in the treated material. - The total nitrogen concentration in the organic wastewater is equal. After the sodium nitrate concentration in the effluent is stabilized, the acclimatization in the anoxic tank is completed. The acclimatization of sodium nitrate concentration is stabilized, meaning that the change in sodium nitrate concentration within 24 hours does not exceed 0.005 g / L.

[0021] Preferably, the acclimatization of the aerobic tank using ammonium chloride specifically involves:

[0022] Nutrients were added to the aerobic tank. After microorganisms accumulated, nutrients and ammonium chloride were continuously added to the aerobic tank to acclimate the microorganisms. The concentration of ammonium chloride was adjusted according to the concentration of FSI in the treated material. - The ammonia nitrogen concentration in the organic wastewater is equal. After the concentration of ammonium chloride in the effluent is stabilized, the acclimatization in the aerobic tank is completed. The acclimatization of ammonium chloride concentration is stabilized, meaning that the concentration change of ammonium chloride within 24 hours does not exceed 0.005 g / L.

[0023] More preferably, the nutrients include phosphates, vitamins, minerals, and a carbon source; the carbon source is sodium acetate.

[0024] Preferably, both the anaerobic and anoxic tanks are equipped with an adjustable stirring device (0-1300 r / min); the aerobic tank is equipped with an aeration disc device at the bottom to evenly disperse oxygen in the wastewater; and the aerobic tank is supplemented with dissolved oxygen by an air pump.

[0025] Preferably, the top of the sedimentation tank is provided with a barrier trough.

[0026] Preferably, nitrification occurs in the aerobic tank to produce nitrified liquid, which is then returned to the anoxic tank for denitrification of nitrates. The anaerobic tank, anoxic tank, and aerobic tank are sequentially coupled by connecting them in series, with the outlet of the aerobic tank connected to the anoxic tank via a tee, and the other outlet of the tee connected to the sedimentation tank.

[0027] Preferably, the activated sludge obtained from the sludge-water separation is returned to the anoxic tank.

[0028] Preferably, the method for separating mud and water is sedimentation.

[0029] This invention also proposes an integrated bioreactor for the above-described method, comprising, in sequence along the wastewater flow direction, an anaerobic tank, an anoxic tank, an aerobic tank, and a sedimentation tank. The anaerobic, anoxic, and aerobic tanks are all inoculated with acclimatized microorganisms. The anaerobic, anoxic, and aerobic tanks are connected in series, with the outlet of the aerobic tank connected to the anoxic tank via a tee, and the other outlet of the tee connected to the sedimentation tank. The anaerobic tank is equipped with an FSI-containing... - The inlet for organic wastewater is provided, and the upper part of the sedimentation tank is equipped with a supernatant outlet.

[0030] Preferably, the pipes connecting the anaerobic tank, anoxic tank, aerobic tank and sedimentation tank are all plastic pipes.

[0031] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0032] (1) The present invention provides a method for using FSI-containing - The biological treatment device for organic wastewater has a simple structure, low cost, stable and reliable operation, convenient operation and maintenance, low energy consumption, and is effective for treating wastewater containing FSI. - The organic wastewater treatment effect is good.

[0033] (2) This invention utilizes microorganisms to degrade FSI in wastewater. - The use of ions and organic matter eliminates the need for or generation of large quantities of chemical agents, reducing environmental pollution and the use of chemicals. Secondly, under suitable conditions, it enables highly efficient wastewater treatment. Microorganisms can decompose organic matter into harmless substances through metabolic activities, achieving the purpose of wastewater treatment. Compared to chemical methods, biological methods are generally less expensive. The operation and maintenance costs of biological methods are relatively low because they do not require frequent additions of expensive chemical agents, and the growth and metabolic processes of microorganisms are relatively stable. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the integrated bioreactor structure described in this invention;

[0035] Figures 2-10 Different concentrations of FSI for this invention - Anion degradation effect diagram;

[0036] Figure 11 This is a high-throughput analysis diagram of different chambers of the integrated bioreactor of the present invention.

[0037] 1-Anaerobic tank; 2-Anoxic tank; 3-Aerobic tank; 4-Sedimentation tank; 5-First peristaltic pump; 6-Second peristaltic pump; 7-Air pump; 8-Inlet; 9-Outlet; Detailed Implementation

[0038] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0039] Example 1

[0040] This embodiment provides a method for using FSI-containing - The specific methods for treating anion-containing wastewater are as follows:

[0041] See appendix Figure 1 As shown, the present invention is used in a material containing FSI - The treatment of anionic wastewater includes an anaerobic tank 1; an anoxic tank 2; an aerobic tank 3; a sedimentation tank 4; a first peristaltic pump 5; a second peristaltic pump 6; an air pump 7; an inlet 8; and an outlet 9. Preferably, the anaerobic tank, anoxic tank, aerobic tank, and sedimentation tank are all connected by plastic pipes.

[0042] The effective volumes of the anaerobic tank, anoxic tank, aerobic tank, and sedimentation tank are 2.5L, 3L, 5.5L, and 5L, respectively. During the treatment process, activated sludge from the wastewater treatment plant is first injected into the anaerobic, anoxic, and aerobic tanks of the reactor using an external peristaltic pump. In this embodiment, the inoculum size of the injected activated sludge is selected as 25%, which introduces microbial strains with active metabolic capabilities into the treatment system.

[0043] Next, the activated sludge in the anaerobic and aerobic tanks was acclimated separately, with acclimation completed after 50-60 days. Specifically, the acclimation process in the anaerobic tank was as follows:

[0044] S1: First, add nutrients to the anaerobic tank to enrich the microorganisms;

[0045] S2: After the microorganisms have completed enrichment, continue to add nutrients and FSI-containing substances to the anaerobic tank. - The compound was used to acclimatize the microorganisms in the anaerobic tank, and the content of FSI in the effluent was tested regularly. - The content of the compound, when two consecutive FSI contents - Once the content of the compound changes to less than the preset value, the acclimatization of the current cycle is completed.

[0046] S3: In subsequent cycles, the concentration of FSI will be gradually increased in a gradient of 10%-20% per cycle. - The amount of compound added is adjusted, and step S2 is repeated; until FSI is achieved. - The amount of compound added and the amount of FSI-containing compound to be treated - FSI in organic wastewater- When the content of the microorganisms is equal and the acclimatization of the microorganisms at that dosage is completed, the acclimatization process of the entire anaerobic tank is finished.

[0047] The FSI-containing compound added in the first cycle of step S2 - The concentration of the compound in the anaerobic feed is the concentration of the FSI-containing compound to be treated. - FSI in organic wastewater - The concentration is 20%.

[0048] The anoxic pond is acclimatized using sodium nitrate, while the aerobic pond is acclimatized using ammonium chloride.

[0049] After acclimatization, the activated sludge in the anaerobic, anoxic, and aerobic tanks showed significant differences in microorganisms. The microorganisms in the anaerobic tank primarily removed biodegradable organic matter from the wastewater, reducing the load on subsequent treatment processes. In the anoxic tank, microorganisms used nitrates and other oxides as electron acceptors to complete denitrification, reducing nitrates and other oxides to gases such as nitrogen. In the aerobic tank, microorganisms used oxygen as an electron acceptor to complete nitrification, oxidizing ammonia nitrogen and other organic nitrogen substances in the wastewater to nitrates and other oxides.

[0050] The nutrients include 1.26 g / L sodium acetate, 1 g / L phosphate, 10 mL / L vitamins, and 75 g / L minerals. In this embodiment, the phosphates are sodium dihydrogen phosphate and disodium hydrogen phosphate. The composition of the vitamins and minerals is shown in Tables 1 and 2, respectively. The concentration of sodium nitrate is 0.1 g / L, and the concentration of ammonium chloride is 0.2 g / L. These nutrients provide the microorganisms with the necessary nutrients and energy.

[0051] Figure 2 This indicates that the concentration of FSI is 452 mg / L. - The removal efficiency of anion-containing wastewater was 67.82%. Samples were taken from the device for testing, and subsequent high-throughput sequencing results were obtained. Figure 11 The main bacterial species that play a role in the device are *Hydrogenophaga* and *norank_f__A4b*.

[0052] Table 1: Vitamin Composition

[0053]

[0054] Table 2: Mineral Composition

[0055]

[0056] Example 2

[0057] Based on the domestication in Example 1, the product containing FSI was placed in an environment of 28°C. - Simulated wastewater with an anion concentration of 320 mg / L enters the anaerobic tank 1 through inlet 8 and is stirred by a stirring device to form a vortex. The vortex force causes FSI - Anions can fully contact and mix with activated sludge, thus achieving preliminary degradation treatment. To further improve reaction efficiency, a stirring speed of 150 rpm can ensure sufficient contact and mixing between the activated sludge and FSI. - Sufficient contact between anionic wastewater and the target wastewater.

[0058] Next, after treatment in anaerobic tank 1, the wastewater enters anoxic tank 2 for further degradation, maintaining an anaerobic or anoxic environment in the reaction system. The stirring motor is started, driving the stirring rod to move the stirring components, ensuring full contact and mixing between the activated sludge and the wastewater. Subsequently, after treatment in anoxic tank 2, organic matter is further removed.

[0059] Next, after treatment in the anoxic tank 2, the wastewater enters the aerobic tank 3. An air pump 7, with a rotor flow meter regulating the airflow rate to 2 L / min, ensures sufficient dissolved oxygen in the aerobic tank, thereby promoting normal microbial metabolism and growth. Simultaneously, nitrification occurs in the aerobic tank, producing nitrified liquid. This nitrified liquid is then transported to the anoxic tank 2 via a second peristaltic pump 6 for denitrification of nitrates in the wastewater.

[0060] Finally, after treatment in aerobic tank 3, the wastewater enters sedimentation tank 4 for settling. The first peristaltic pump 5 transports a portion of the sludge to anoxic tank 2 to provide sufficient activated sludge seed, and the supernatant is discharged from outlet 9. Through this series of reaction processes, the entire treatment system can efficiently remove FSI. - Organic matter and pollutants in anion-containing wastewater.

[0061] FSI at the inlet and outlet of this embodiment - The concentration of anions was detected. Figure 3 This indicates an FSI concentration of 320 mg / L. - The removal efficiency of anion-containing wastewater was 49.92%. Samples were taken from the contents of the device for testing, and the high-throughput sequencing results were obtained as follows: Figure 11 The main bacterial species that play a role in the device are *Hydrogenophaga* and *norank_f__A4b*.

[0062] Example 3

[0063] Based on the domestication in Example 1, FSI was subjected to treatment at 28°C. -Simulated wastewater with an anion concentration of 246 mg / L enters the anaerobic tank 1 through inlet 8 and is stirred by a stirring device to fully contact and mix with the activated sludge, thereby achieving preliminary degradation treatment. The stirring speed is 150 rpm.

[0064] Next, after treatment in anaerobic tank 1, the wastewater enters anoxic tank 2 for further degradation, maintaining an anaerobic or hypoxic environment in the reaction system. The stirring motor is started, driving the stirring rod to move the stirring components, ensuring full contact and mixing between the activated sludge and the wastewater, further removing organic matter.

[0065] Next, after treatment in the anoxic tank 2, the wastewater enters the aerobic tank 3. The air flow rate is adjusted to 2 L / min by an air pump 7 and a rotor flow meter. Simultaneously, nitrification occurs in the aerobic tank, producing nitrified liquid. This nitrified liquid is then transported to the anoxic tank 2 by a second peristaltic pump 6 for denitrification of the nitrates in the wastewater.

[0066] Finally, after treatment in aerobic tank 3, the wastewater enters sedimentation tank 4 for settling. The first peristaltic pump 5 transports part of the sludge to anoxic tank 2 and discharges the supernatant from outlet 9.

[0067] FSI at the inlet and outlet of this embodiment - The concentration of anions was detected. Figure 4 This indicates an FSI concentration of 246 mg / L. - The removal efficiency of anion-containing wastewater was 58.1%. Samples were taken from the contents of the device for testing, and the high-throughput sequencing results were obtained as follows: Figure 11 This indicates that the main active bacteria in the device are *Hydrogenophaga* and *norank_f__A4b*.

[0068] Example 4

[0069] Based on the domestication in Example 1, FSI was subjected to treatment at 28°C. - Simulated wastewater with an anion concentration of 189 mg / L enters the anaerobic tank 1 through inlet 8 and is stirred by a stirring device to fully contact and mix with the activated sludge, thereby achieving preliminary degradation treatment. The stirring speed is 150 rpm.

[0070] Next, after undergoing the same treatment process as in Examples 2 and 3 in anaerobic tank 1, anoxic tank 2 and sedimentation tank 4, the supernatant is discharged from outlet 9.

[0071] FSI at the inlet and outlet of this embodiment - The concentration of anions was detected. Figure 5 This indicates an FSI concentration of 189 mg / L. -The removal efficiency of anion-containing wastewater was 86.1%. Samples were taken from the contents of the device for testing, and the high-throughput sequencing results were obtained as follows: Figure 11 The test results showed that the main bacteria species playing a role in the device were *Hydrogenophaga* and *norank_f__A4b*.

[0072] Example 5

[0073] Based on the domestication in Example 1, FSI was subjected to treatment at 28°C. - Simulated wastewater with an anion concentration of 150 mg / L enters the anaerobic tank 1 through inlet 8 and is stirred by a stirring device to fully contact and mix with the activated sludge, thereby achieving preliminary degradation treatment. The stirring speed is 150 rpm.

[0074] Next, after undergoing the same treatment process as in Examples 2 and 3 in anaerobic tank 1, anoxic tank 2 and sedimentation tank 4, the supernatant is discharged from outlet 9.

[0075] FSI at the inlet and outlet of this embodiment - The concentration of anions was detected. Figure 6 This indicates an FSI concentration of 150 mg / L. - The removal efficiency of anion-containing wastewater was 89.9%. Samples were taken from the contents of the device for testing, and the high-throughput sequencing results were obtained as follows: Figure 11 The test results showed that the main bacteria species playing a role in the device were *Hydrogenophaga* and *norank_f__A4b*.

[0076] Example 6

[0077] Based on the domestication in Example 1, FSI was subjected to treatment at 28°C. - Simulated wastewater with an anion concentration of 100 mg / L enters the anaerobic tank 1 through inlet 8 and is stirred by a stirring device to fully contact and mix with the activated sludge, thereby achieving preliminary degradation treatment. The stirring speed is 150 rpm.

[0078] Next, after undergoing the same treatment process as in Examples 2 and 3 in anaerobic tank 1, anoxic tank 2 and sedimentation tank 4, the supernatant is discharged from outlet 9.

[0079] FSI at the inlet and outlet of this embodiment - The concentration of anions was detected. Figure 7 This indicates an FSI concentration of 100 mg / L. - The removal efficiency of anion-containing wastewater was 80.4%. Samples were taken from the contents of the device for testing, and the high-throughput sequencing results were obtained as follows: Figure 11The test results showed that the main bacteria species playing a role in the device were *Hydrogenophaga* and *norank_f__A4b*.

[0080] Example 7

[0081] Based on the domestication in Example 1, FSI was subjected to treatment at 28°C. - Simulated wastewater with anion concentration of 55 mg / L enters the anaerobic tank 1 through inlet 8 and is stirred by a stirring device to fully contact and mix with the activated sludge, thereby achieving preliminary degradation treatment. The stirring speed is 150 rpm.

[0082] Next, after undergoing the same treatment process as in Examples 2 and 3 in anaerobic tank 1, anoxic tank 2 and sedimentation tank 4, the supernatant is discharged from outlet 9.

[0083] FSI at the inlet and outlet of this embodiment - The concentration of anions was detected. Figure 8 This indicates an FSI concentration of 55 mg / L. - The removal efficiency of anion-containing wastewater was 63.6%. Sampling and testing of the contents of the device yielded the following high-throughput sequencing results: Figure 11 The test results showed that the main bacteria species playing a role in the device were *Hydrogenophaga* and *norank_f__A4b*.

[0084] Example 8

[0085] Based on the domestication in Example 1, FSI was subjected to treatment at 28°C. - The simulated wastewater with anionic wastewater concentration of 25 mg / L enters the anaerobic tank 1 through inlet 8 and is stirred by a stirring device to fully contact and mix with the activated sludge, thereby achieving preliminary degradation treatment. The stirring speed is 150 rpm.

[0086] Next, after undergoing the same treatment process as in Examples 2 and 3 in anaerobic tank 1, anoxic tank 2 and sedimentation tank 4, the supernatant is discharged from outlet 9.

[0087] FSI at the inlet and outlet of this embodiment - The concentration of anions was detected. Figure 9 This indicates an FSI concentration of 25 mg / L. - The removal efficiency of anion-containing wastewater was 40.1%. Samples were taken from the contents of the device for testing, and the high-throughput sequencing results were obtained as follows: Figure 11 The test results showed that the main bacteria species playing a role in the device were *Hydrogenophaga* and *norank_f__A4b*.

[0088] Example 9

[0089] Based on the domestication in Example 1, FSI was subjected to treatment at 28°C. - Simulated wastewater with an anion concentration of 15 mg / L enters the anaerobic tank 1 through inlet 8 and is stirred by a stirring device to fully contact and mix with the activated sludge, thereby achieving preliminary degradation treatment. The stirring speed is 150 rpm.

[0090] Next, after undergoing the same treatment process as in Examples 2 and 3 in anaerobic tank 1, anoxic tank 2 and sedimentation tank 4, the supernatant is discharged from outlet 9.

[0091] FSI at the inlet and outlet of this embodiment - The concentration of anions was detected. Figure 10 This indicates that the simulated wastewater at a concentration of 15 mg / L had almost no removal effect. Further high-throughput sequencing results were obtained from sampling and testing of the contents of the device. Figure 11 The test results showed that the main bacteria species playing a role in the device were *Hydrogenophaga* and *norank_f__A4b*.

[0092] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. Those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A method for using FSI - A biological method for treating organic wastewater, characterized in that, include: 1) The activated sludge was injected into the anaerobic tank, anoxic tank and aerobic tank respectively for acclimatization; During the acclimatization process, the anaerobic, anoxic, and aerobic tanks were kept independent of each other, maintaining dissolved oxygen levels of 0-0.5 mg / L, 0.5-1.5 mg / L, and 2-4 mg / L in the anaerobic, anoxic, and aerobic tanks, respectively. The acclimatization process was divided into several cycles, during which the anaerobic tank utilized FSI-containing... - The compounds containing ions were acclimatized in anoxic ponds using sodium nitrate. The concentration of sodium nitrate was compared with that of the FSI-containing compounds being treated. - The total nitrogen concentration in the organic wastewater is equal; the aerobic tank is acclimated using ammonium chloride, and the concentration of ammonium chloride is the same as that of the FSI-containing wastewater to be treated. - The ammonia nitrogen concentration in the organic wastewater is equal; after the acclimatization is completed, the anaerobic tank, anoxic tank and aerobic tank are sequentially coupled. The acclimatization process in the anaerobic tank is as follows: S1: First, add nutrients to the anaerobic tank to enrich the microorganisms; S2: After the microorganisms have completed enrichment, continue to add nutrients and FSI-containing substances to the anaerobic tank. - The compound was used to acclimatize the microorganisms in the anaerobic tank, and the content of FSI in the effluent was tested regularly. - The content of the compound, when two consecutive FSI contents - Once the content of the compound changes to less than the preset value, the acclimatization of the current cycle is completed. S3: Subsequent cycles gradually increase the inclusion of FSI - The amount of compound added is adjusted, and step S2 is repeated; until FSI is achieved. - The amount of compound added and the amount of FSI-containing compound to be treated - FSI in organic wastewater - When the content of the microorganisms is equal and the acclimatization of the microorganisms at that addition amount is completed, the acclimatization process of the entire anaerobic tank is over. The FSI-containing component added in the first cycle - The concentration of the compound in the anaerobic feed is the concentration of the FSI-containing compound to be treated. - FSI in organic wastewater - The concentration was 20%; in subsequent cycles, the concentration of FSI was increased by a gradient of 10%-20%. - The amount of the compound added; 2) Passing through FSI - The organic wastewater first enters the anaerobic tank, where it comes into contact with and mixes with the activated sludge. The FSI in the wastewater... - FSI in wastewater undergoes biochemical degradation. - As a supplementary source of nutrients N and S, it is initially absorbed and degraded by microorganisms in the anaerobic pond; 3) The wastewater treated in the anaerobic tank enters the anoxic tank for further degradation and removal of organic matter; 4) After being treated in the anoxic tank, the wastewater enters the aerobic tank, where the ammonia nitrogen in the wastewater undergoes nitrification. 5) The wastewater treated in the aerobic tank is discharged into the aerobic tank for mud-water separation, and the separated liquid is discharged.

2. The method for using FSI according to claim 1 - A biological method for treating organic wastewater, characterized in that, The acclimatization process in the anoxic pool is as follows: Nutrients are added to the anoxic tank. After the microorganisms have accumulated, nutrients and sodium nitrate are continuously added to the anoxic tank to acclimate the microorganisms. Once the concentration of sodium nitrate in the effluent remains stable, the acclimatization of the anoxic tank is complete.

3. The method for using FSI according to claim 1 - A biological method for treating organic wastewater, characterized in that, For aerobic ponds, ammonium chloride is used for acclimatization, specifically as follows: Nutrients are added to the aerobic tank. After the microorganisms have accumulated, nutrients and ammonium chloride are continuously added to the aerobic tank to acclimate the microorganisms. Once the concentration of ammonium chloride in the effluent has stabilized, the acclimatization of the aerobic tank is complete.

4. The method for using FSI according to any one of claims 1-3 - A biological method for treating organic wastewater, characterized in that, The nutrients include phosphates, vitamins, minerals, and a carbon source; the carbon source is sodium acetate.

5. The method for using FSI according to claim 1 - A biological method for treating organic wastewater, characterized in that, Both the anaerobic and anoxic tanks are equipped with stirring devices; the aerobic tank is supplemented with dissolved oxygen by an air pump.

6. The method for using FSI according to claim 1 - A biological method for treating organic wastewater, characterized in that, The aerobic tank undergoes a nitrification reaction to produce nitrified liquid, which is then returned to the anoxic tank for denitrification of nitrates. The anaerobic tank, anoxic tank, and aerobic tank are sequentially coupled by connecting them in series, with the outlet of the aerobic tank connected to the anoxic tank via a tee, and the other outlet of the tee connected to the sedimentation tank.

7. The method for using FSI according to claim 1 - A biological method for treating organic wastewater, characterized in that, The activated sludge obtained from the sludge-water separation is returned to the anoxic tank; the sludge-water separation method is sedimentation.

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