Layered feeding type multi-strain-ceramsite carrier compound preparation and application thereof in culture sewage denitrification purification

Abstract

The invention belongs to the technical field of biological denitrification of aquaculture sewage, and particularly relates to a multi-strain-ceramsite carrier compound for static denitrification purification of aquaculture sewage as well as a preparation method and application of the multi-strain-ceramsite carrier compound. The compound is composed of eight strains of cellulomonas flavigena, bacillus subtillis, bacillus licheniformis, leuconostoc mesenteroides, pediococcus pentosaceus and paracoccus denitrificans, and the eight strains are loaded on a ceramsite carrier through a special process. When the compound disclosed by the invention is used for treating aquaculture sewage, a layered bacterium feeding mode is adopted, and odor can be remarkably inhibited when water is efficiently purified. Practical application results show that after being treated by the compound, the removal rates of total nitrogen, ammonia nitrogen and COD (Chemical Oxygen Demand) in the breeding sewage respectively reach 89.2%, 91.2% and 82.2%. According to the invention, through synergistic interaction of multiple strains, process optimization and accurate regulation and control of spatial distribution, efficient static purification of aquaculture sewage is realized, and an economical and feasible technical path is provided for rural environmental pollution abatement.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of biological denitrification of aquaculture wastewater, and particularly relates to a layered adding type multi-strain-ceramic carrier compound and application thereof in denitrification and purification of aquaculture wastewater. BACKGROUND

[0002] Under the active promotion of national policies, China's rural aquaculture industry has achieved a major transformation from the traditional individual model to large-scale development in recent years, and the aquaculture level has been significantly improved. However, this development process has also brought environmental problems that cannot be ignored, especially the large amount of livestock and poultry wastewater produced by the aquaculture industry, which has become the main source of rural non-point source pollution. These wastewaters are complex in composition and contain a large amount of poultry manure, urine and undigested feed. Under the condition of direct discharge without effective treatment, the organic matter such as protein, starch, oil and cellulose in the feed can easily lead to water eutrophication and water quality deterioration, posing a serious threat to the ecological environment.

[0003] To address the challenges of aquaculture wastewater treatment, a series of policies and regulations have been introduced at the national level to provide a clear direction for wastewater treatment and resource utilization.

[0004] Currently, there are various methods for treating aquaculture wastewater, including physical, chemical, land treatment and biological treatment methods. However, each of these methods has its limitations: physical methods have limited effect on dissolved pollutants; chemical methods are high in treatment cost and can easily cause secondary pollution; land treatment methods are slow in effect and may pose a risk of heavy metal accumulation; biological treatment methods have the advantages of large treatment capacity, low cost and no secondary pollution, but their treatment effect is easily affected by environmental factors, and unreasonable strain combination or poor adaptability can lead to low denitrification efficiency. In particular, in mountainous rural areas, due to economic constraints, high-cost wastewater treatment equipment is difficult to popularize. Therefore, developing a multi-strain-ceramic carrier compound with strong adaptability, low cost and suitable for static treatment has urgent practical significance for achieving efficient denitrification and purification of aquaculture wastewater in mountainous areas. SUMMARY

[0005] The purpose of the present application is to provide a layered adding type multi-strain-ceramic carrier compound and its application in denitrification and purification of aquaculture wastewater, aiming to solve the problem of aquaculture wastewater pollution.

[0006] To achieve the above objectives, this invention provides a multi-strain-ceramsite carrier complex for denitrification and purification of aquaculture wastewater. By mass percentage, the multi-strain-ceramsite carrier complex comprises 15%-20% *Cellulomonas flavipena*, 15%-25% *Bacillus subtilis*, 15%-20% *Bacillus licheniformis*, 10%-15% *Leuconostoc mesenteroides*, 7%-10% *Rhodopseudomonas sphaeroides*, 5%-10% *Rhodopseudomonas palustris*, 10% *Pediococcus pentasaceus*, and 5% *Paracoccus denitrificans*. The total bacterial count of the multi-strain-ceramsite carrier complex is ≥1×10⁻⁶. 9 -1×10 11 CFU / g.

[0007] Further details are provided: *Cellulomonas flavigena* has accession number BMZ134560; *Bacillus subtilis* has accession number BMZ339677; *Bacillus licheniformis* has accession number BMZ137481; *Leuconostocmesenteroides* has accession number CGMCC 1.2138; *Rhodopseudomonassphaeroides* has accession number CGMCC 1.2182; *Rhodopseudomonas palustris* has accession number BMZ121828; *Pediococcus pentasaceus* has accession number BMZ123303; and *Paracoccus* has accession number BMZ123303. The accession number for the denitrificans is BMZ010503.

[0008] This invention also provides a method for preparing the multi-strain-ceramsite carrier complex for denitrification and purification of aquaculture wastewater as described above. Specifically, it involves liquid fermentation culture of *Cellulomonas flavigena* using modified CMC medium, *Bacillus subtilis* using modified LB medium, *Bacillus licheniformis* using high-density fermentation medium, *Leuconostoc mesenteroides* using modified MRS medium, *Rhodopseudomonas sphaeroides* using photosynthetic bacteria basal medium, *Rhodopseudomonas palustris* using optimized photosynthetic bacteria medium, *Pediococcus pentasaceus* using high-density seed medium, and *Paracoccus denitrifyingis*. (denitrificans) were cultured separately in broth medium for liquid fermentation. The number of viable cells was measured. After centrifugation, the fermentation broth was removed and diluted to a concentration ≥1×10⁻⁶. 9 CFU / mL was mixed separately with the carrier material, solidified and dried to obtain a multi-strain-ceramsite carrier complex for denitrification and purification of aquaculture wastewater; total viable count ≥1×10⁻⁶. 9 -1×10 11 CFU / g.

[0009] To further clarify, the eight strains underwent activation treatment before fermentation. *Cellulomonas flavigena*, *Bacillus subtilis*, *Bacillus licheniformis*, *Leuconostoc mesenteroides*, *Rhodopseudomonas sphaeroides*, *Rhodopseudomonas palustris*, *Pediococcus pentasaceus*, and *Paracoccus denitrificans* were activated individually. The activated bacterial solutions were then sequentially inoculated into 10%, 20%, 50%, and 100% sterilized aquaculture wastewater for acclimatization and culture. Finally, each strain was inoculated into its corresponding culture medium for cultivation and preserved as seed culture.

[0010] To further clarify, the sterilized livestock wastewater is wastewater obtained through a soaking manure cleaning process; the livestock wastewater includes, but is not limited to, wastewater from pig farms using a soaking manure cleaning process or a dry manure cleaning process, which contains urine, feces, and pen flushing water, contains no disinfectants or sodium hydroxide that are detrimental to the growth of microorganisms, and is pig farm wastewater discharged within one week.

[0011] To further explain, the carrier material is ceramsite; the ceramsite is floating ceramsite and / or suspended ceramsite and / or sinking ceramsite; the carrier material can increase air permeability and compatibility and easily form a biofilm on its surface, which is conducive to bacterial attachment and metabolic activities.

[0012] Further explanation: The *Xanthomonas xanthogenes* and the floating ceramsite carrier are mixed at a bacterial volume:carrier mass ratio of 1:1 (L / kg) to form a strain-carrier complex; the *Bacillus subtilis* and the floating ceramsite carrier are mixed at a bacterial volume:carrier mass ratio of 1:0.2 (L / kg) to form a strain-carrier complex; the *Bacillus licheniformis* and the floating ceramsite carrier are mixed at a bacterial volume:carrier mass ratio of 1:0.2 (L / kg) to form a strain-carrier complex; the *Leuconostoc mesenteriae* and the suspended ceramsite carrier are mixed at a bacterial volume:carrier mass ratio of 1:0.2 (L / kg) to form a strain-carrier complex. The following are strain-carrier complexes: *Rhodopseudomonas spheroidae* and the submerged ceramsite carrier are mixed at a bacterial volume:carrier mass ratio of 1:0.2 (L / kg) to form a strain-carrier complex; *Rhodopseudomonas palustris* and the submerged ceramsite carrier are mixed at a bacterial volume:carrier mass ratio of 1:0.2 (L / kg) to form a strain-carrier complex; *Pediococcus pentosaceus* and the suspended ceramsite carrier are mixed at a bacterial volume:carrier mass ratio of 1:0.2 (L / kg) to form a strain-carrier complex; *Paragonimococcus denitrificans* and the submerged ceramsite carrier are mixed at a bacterial volume:carrier mass ratio of 1:2 (L / kg) to form a strain-carrier complex.

[0013] This invention also provides a method for denitrification and purification of aquaculture wastewater. The multi-strain-ceramsite carrier complex prepared above is added to a wastewater pond with a depth of, but not limited to, 2 meters. The multi-strain-carrier complex is added in layers, in the order of bottom layer, middle layer and surface layer. First, the submerged strain-carrier complex of Rhodopseudomonas palustris, Rhodopseudomonas spheroidae, and Paracoccus denitrifying is added to the bottom layer of the low dissolved oxygen / anaerobic zone at 1.5-2 meters. Then, the suspended strain-carrier complex of Pediococcus pentosaceus and Leuconostoc mesenteroides is added to the middle layer of the medium-low dissolved oxygen zone at 0.5-1.5 meters. Finally, the floating strain-carrier complex of Bacillus subtilis, Bacillus licheniformis, and Fibromosporium xanthogenes is added to the surface layer of the high dissolved oxygen zone at 0-0.5 meters.

[0014] To further explain, the multi-strain-ceramsite carrier complex is activated before being added to wastewater. The activation solution consists of Activation Solution I and Activation Solution II. Activation Solution I is composed of Bacillus licheniformis and Bacillus subtilis, while Activation Solution II is composed of Flavobacterium xanthogenes, Leuconostoc mesenteroides, Rhodopseudomonas spheroidosa, Rhodopseudomonas palustris, Pediococcus pentosaceus, and Paracoccus denitrificans. Activation Solution I is composed of sterile water, 0.3% glucose, and 0.4% peptone. Activation Solution II is composed of 0.3% glucose, 0.4% peptone, 0.3% sodium acetate, and 0... The mixture consists of 0.5% ammonium chloride, 0.5% sodium thiomethylcellulose, 0.1% potassium dihydrogen phosphate, 0.2% potassium nitrate, 0.15% yeast extract, and 0.2% sucrose. The strain-ceramsite carrier complex is mixed with the activation solution at a mass-to-volume ratio of 1:10 and poured into a transparent plastic container, ensuring that the carrier is completely submerged. The total proportion of the carrier should not exceed 1 / 3 of the volume of the mixed solution. Activation takes 8-10 hours. The dosage of the multi-strain-ceramsite carrier complex is 150-200g per cubic meter of wastewater, and the strain-carrier complex is added in layers.

[0015] To further explain, this multi-strain-ceramsite carrier composite material is suitable for denitrification and purification equipment for aquaculture wastewater. When used for static denitrification and purification of aquaculture wastewater, it is applied in a layered manner to match the environmental conditions at different depths of the water body. To ensure the activity of the strains and the denitrification effect, the temperature of the wastewater needs to be controlled within the range of 22℃-36℃, the pH value needs to be adjusted within the range of 6.5-8.2, and the C / N ratio of the wastewater needs to be adjusted to 5:2-8:1. The cover should be made of a light-transmitting material or a 620-650 LED array should be arranged around the equipment, with a light intensity ≥5000 lux and a daily light exposure time of 8:00-18:00.

[0016] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0017] (1) Multi-strain stratified precise denitrification, with significant synergistic purification efficiency.

[0018] This technology utilizes the dissolved oxygen gradient in water to implement precise, stratified bacterial inoculation.

[0019] Surface layer (high-oxygen zone): Aerobic bacteria (such as Bacillus subtilis) dominate the decomposition of macromolecular organic matter and inhibit the diffusion of organic nitrogen.

[0020] Middle layer (low-oxygen zone): Facultative anaerobic bacteria (Pediococcus pentosus, etc.) treat small-molecule organic nitrogen and stabilize the pH of the water.

[0021] Bottom layer (anaerobic zone): Anaerobic bacteria (such as Rhodopseudomonas swampensis) complete denitrification, thoroughly removing nitrates from the bottom layer.

[0022] Through the complementary and synergistic effects of the bacterial communities at each layer, the system ultimately achieves highly efficient removal of total nitrogen, ammonia nitrogen, and COD (with degradation rates all exceeding 82%), demonstrating outstanding static water purification capabilities.

[0023] (2) Porous ceramic aggregate carrier to ensure long-term water purification

[0024] This technology employs a strain-ceramsite carrier composite form, relying on the porous structure of the ceramsite to provide a stable "habitat" for microorganisms, effectively addressing the challenges of easy loss of microorganisms and difficulty in colonization, and achieving slow release of the microbial agent, thereby significantly extending the effective period and ensuring the continuity of the purification effect.

[0025] (3) Precise strain location and on-demand activation of functions

[0026] This technology employs a stratified dosing strategy to precisely spatially distribute bacterial strains in the water according to their oxygen requirements. This approach successfully avoids oxygen competition among bacterial communities and, through differentiated dissolved oxygen and light regulation (e.g., providing low light for Rhodopseudomonas palustris), ensures that various bacterial communities can function at their optimal "workstations," thereby driving a significant enhancement in overall denitrification efficiency.

[0027] (4) Significantly reduce costs and increase efficiency, and effectively avoid ecological risks.

[0028] This solution boasts low operating costs and minimal environmental risk. The process requires no complex aeration or mixing equipment, and post-implementation management is simple. Furthermore, the reusable nature of the expanded clay pellets significantly lowers the technical barriers and long-term costs. Simultaneously, the bacterial strains are immobilized on the expanded clay pellets, eliminating the risk of escape with the effluent and ensuring environmental safety. This solution perfectly meets the practical needs and conditions of rural farms in mountainous areas.

[0029] (5) Green and low-carbon technologies empower agriculture and promote a win-win situation for pollution control and economic development.

[0030] This technology employs a near-zero-energy biological denitrification process, replacing high-energy-consuming physicochemical methods, thus achieving energy conservation and carbon reduction at the source. The ceramsite carrier used is regenerable and can be recycled by reloading it with microbial agents, effectively reducing solid waste generation and aligning with the low-carbon circular economy concept.

[0031] This technology can effectively control livestock pollutants at the source, providing a reliable solution for agricultural non-point source pollution control, helping to promote the transformation of agricultural production from "high pollution and high consumption" to "green and ecological", and providing solid technical support for the implementation of my country's "dual carbon" goals and the construction of ecological civilization. Attached Figure Description

[0032] Figure 1 The graph shows a comparison of the degradation rates of total nitrogen (TN), ammonia nitrogen (NH4⁺-N), and COD in aquaculture wastewater treatment using the multi-strain-ceramsite carrier complex in Examples 9, 10, and 11.

[0033] Figure 2 This is a diagram showing the changes in the appearance of wastewater before and after treatment. Detailed Implementation

[0034] All features disclosed in this specification, or steps in all methods or processes disclosed herein, may be combined in any way, except for mutually exclusive features and / or steps.

[0035] Unless otherwise stated, each feature disclosed in this specification (including any appended claims and abstract) is merely one example of a series of equivalent or similar features.

[0036] The strains used in this invention are from the following sources:

[0037] The accession number for *Cellulomonas flavigena* is BMZ134560.

[0038] The accession number for Bacillus subtilis is BMZ339677.

[0039] The accession number for Bacillus licheniformis is BMZ137481.

[0040] The accession number for *Leuconostoc mesenteroides* is CGMCC 1.2138.

[0041] The accession number for *Rhodopseudomonas sphaeroides* is CGMCC 1.2182.

[0042] The accession number for *Rhodopseudomonas palustris* is BMZ121828.

[0043] The accession number for *Pediococcus pentasaceus* is BMZ123303.

[0044] The accession number for Paracoccus denitrificans is BMZ010503.

[0045] All of the strains listed above are for sale and can be purchased on the market.

[0046] The culture medium composition formula used in this invention is as follows:

[0047] Oil culture medium: 1g peptone, 0.3g beef extract, 1g peanut oil, 0.5g sodium chloride, 0.01ml neutral red (1.6% aqueous solution), 2.8g agar powder, 100ml ultrapure water, pH 7.2-7.4, autoclaved at 121℃ for 20min.

[0048] Broth culture medium: 0.3% beef extract, 1.0% peptone, 0.5% NaCl, 100ml ultrapure water, pH at rest, autoclaved at 121℃ for 20min.

[0049] LB medium: 1g tryptone, 0.5g yeast extract, 0.5g sodium chloride, 100ml ultrapure water, pH at rest, autoclave at 121℃ for 20min.

[0050] Starch culture medium: 10g peptone, 3g beef extract, 5g sodium chloride, 28g agar powder, 2g soluble starch, 1000ml ultrapure water, pH 7.2-7.4, autoclaved at 121℃ for 20min.

[0051] Milk culture medium: 1000 ml of nutrient agar (3% agar powder), autoclaved at 121℃ for 20 min. 10g milk powder added to 200ml of ultrapure water, autoclaved at 121℃ for 20 min. Finally, mix the nutrient agar and milk powder solution at a ratio of 100:20.

[0052] CMC medium: 1.0% straw powder + 0.6% compound nitrogen source + 0.1% KH2PO4 + 0.1% MgSO4.

[0053] Modified CMC medium: microcrystalline cellulose 10 g / L, soybean meal hydrolysate 8 g / L, KH2PO4 1.5 g / L, MgSO4·7H2O 0.3 g / L, CaCl2 0.1 g / L, cellulose inducing factor 0.05%.

[0054] LB modified medium: glucose 20 g / L, peptone 15 g / L, NaCl 5 g / L, beef extract 0.5 g / L, MnSO4·H2O 0.005 g / L (to promote spore formation).

[0055] High-density fermentation medium: yeast extract 7.5 g / L, gelatin 10 g / L, CaCl2 5 g / L.

[0056] Modified MRS medium: sucrose 50 g / L, tomato juice 10% (v / v), ascorbic acid 2 g / L (reducing agent).

[0057] Basic culture medium for photosynthetic bacteria: K2HPO4 3 g / L, KH2PO4 1 g / L, (NH4)2NO3 0.5 g / L, Na2SO3 0.1 g / L, yeast extract 0.1 g / L, glucose 10 g / L, sodium acetate 5 g / L.

[0058] Optimize the photosynthetic bacteria culture medium: NH4Cl 1 g / L, K2HPO4 0.5 g / L, NaHCO3 3 g / L, yeast extract 2 g / L.

[0059] High-density seed culture medium: glucose 35 g / L, yeast powder 10 g / L, beef extract 10 g / L, sodium acetate 6 g / L, K2HPO4 2 g / L, Tween 80 1.5 mL / L.

[0060] Example 1: Preparation of a composite material of aquaculture wastewater denitrification and purification strains and ceramic carrier.

[0061] The specific method for preparing a composite material of aquaculture wastewater denitrification and purification strains and ceramic carriers in this embodiment is as follows:

[0062] Cellulomonas flavigena was cultured in modified CMC medium at 30°C, pH 7.2, 120 rpm, DO 30%, for 48 h using liquid fermentation. The OD value was measured at 600 nm. After centrifugation at 0.8-1.5 nm, the fermentation broth was removed and diluted to a concentration ≥1×10⁻⁶. 9 CFU / mL bacterial suspension was mixed with the floating ceramsite carrier at a bacterial volume: carrier mass = 1:1 (L / kg), solidified and dried to prepare a bacterial strain-ceramsite carrier complex, which is then used to treat aquaculture wastewater for denitrification and purification.

[0063] Example 2: Preparation of a composite material of aquaculture wastewater denitrification and purification strains and ceramic carrier.

[0064] The specific method for preparing a composite material of aquaculture wastewater denitrification and purification strains and ceramic carriers in this embodiment is as follows:

[0065] Bacillus subtilis was cultured in modified LB medium at 37°C and 180 rpm for 24 hours via liquid fermentation. The OD value at 600 nm was measured to be 1.0–2.0. After centrifugation, the fermentation broth was removed and diluted to a concentration ≥1×10⁻⁶. 9 CFU / mL bacterial suspension was mixed with the floating ceramsite carrier at a ratio of bacterial suspension volume to carrier mass of 1:0.2 (L / kg), solidified and dried to prepare a bacterial strain-ceramsite carrier complex, which is then used to treat aquaculture wastewater for denitrification and purification.

[0066] Example 3: Preparation of a composite material of aquaculture wastewater denitrification and purification strains and ceramic carrier.

[0067] The specific method for preparing a composite material of aquaculture wastewater denitrification and purification strains and ceramic carriers in this embodiment is as follows:

[0068] Bacillus licheniformis Weigmann was cultured in high-density fermentation medium at 37°C and 150 rpm for 24 hours. The OD value at 600 nm was measured to be 1.0–2.0. After centrifugation, the fermentation broth was removed and diluted to a concentration ≥1×10⁻⁶. 9 CFU / mL bacterial suspension was mixed with the floating ceramsite carrier at a ratio of bacterial suspension volume to carrier mass of 1:0.2 (L / kg), solidified and dried to prepare a bacterial strain-ceramsite carrier complex, which is then used to treat aquaculture wastewater for denitrification and purification.

[0069] Example 4: Preparation of a composite material of aquaculture wastewater denitrification and purification strains and ceramic carrier.

[0070] The specific method for preparing a composite material of aquaculture wastewater denitrification and purification strains and ceramic carriers in this embodiment is as follows:

[0071] Leuconostoc mesenteroides was cultured anaerobically at 30°C in modified MRS medium for 36 hours. OD values ​​were measured at 600 nm. After centrifugation at 0.8-1.5 nm, the fermentation broth was removed, and the culture was diluted to a concentration ≥1×10⁻⁶. 9 CFU / mL bacterial suspension was mixed with the suspended ceramsite carrier at a ratio of bacterial volume to carrier mass of 1:0.2 (L / kg), solidified and dried to prepare a bacterial strain-ceramsite carrier complex, which is then used for denitrification treatment of aquaculture wastewater.

[0072] Example 5: Preparation of a composite material of aquaculture wastewater denitrification and purification strains and ceramic carrier.

[0073] The specific method for preparing a composite material of aquaculture wastewater denitrification and purification strains and ceramic carriers in this embodiment is as follows:

[0074] Rhodopseudomonas sphaeroides was cultured separately in photosynthetic bacteria basal medium for liquid fermentation at 28°C under 2000 lux light for 72 h. The OD value at 600 nm was measured to be 1.0-2.0. After centrifugation, the fermentation broth was removed and diluted to a concentration ≥1×10⁻⁶. 9CFU / mL bacterial suspension was mixed with the submersible ceramsite carrier at a ratio of bacterial suspension volume to carrier mass of 1:0.2 (L / kg), solidified and dried to prepare a bacterial strain-ceramsite carrier complex, which is then used for denitrification treatment of aquaculture wastewater.

[0075] Example 6: Preparation of a composite material of aquaculture wastewater denitrification and purification strains and ceramic carrier.

[0076] The specific method for preparing a composite material of aquaculture wastewater denitrification and purification strains and ceramic carriers in this embodiment is as follows:

[0077] Rhodopseudomonas palustris was cultured separately in liquid fermentation medium using an optimized photosynthetic bacteria medium at 35°C under 2000 lux light. After standing for 72 hours, the OD value at 600 nm was measured to be 1.0–2.0. After centrifugation, the fermentation broth was removed and diluted to a concentration ≥1×10⁻⁶. 9 CFU / mL bacterial suspension was mixed with the submersible ceramsite carrier at a ratio of bacterial suspension volume to carrier mass of 1:0.2 (L / kg), solidified and dried to prepare a bacterial strain-ceramsite carrier complex, which is then used for denitrification treatment of aquaculture wastewater.

[0078] Example 7: Preparation of a composite material of aquaculture wastewater denitrification and purification strains and ceramsite carriers.

[0079] The specific method for preparing a composite material of aquaculture wastewater denitrification and purification strains and ceramic carriers in this embodiment is as follows:

[0080] Pediococcus pentasaceus was cultured statically at 37°C in high-density seed culture medium for 24 hours, followed by liquid fermentation. The OD value at 600 nm was measured. After centrifugation at 0.6-1.2, the fermentation broth was removed and diluted to a concentration ≥1×10⁻⁶. 9 CFU / mL bacterial suspension was mixed with the suspended ceramsite carrier at a ratio of bacterial volume to carrier mass of 1:0.2 (L / kg), solidified and dried to prepare a bacterial strain-ceramsite carrier complex, which is then used for denitrification and purification of aquaculture wastewater.

[0081] Example 8: Preparation of a composite material of aquaculture wastewater denitrification and purification strains and ceramic carrier.

[0082] The specific method for preparing a composite material of aquaculture wastewater denitrification and purification strains and ceramic carriers in this embodiment is as follows:

[0083] Paracoccus denitrificans was cultured statically at 37°C in LB medium for 24 hours, followed by liquid fermentation. The OD value at 600 nm was measured. After centrifugation, the fermentation broth was removed and diluted to a concentration ≥1×10⁻⁶. 9 CFU / mL bacterial suspension was mixed with the submersible ceramsite carrier at a ratio of bacterial suspension volume to carrier mass of 1:2 (L / kg), solidified and dried to prepare a bacterial strain-ceramsite carrier complex, which is then used for denitrification and purification of aquaculture wastewater.

[0084] Example 9: Preparation of a multi-strain-ceramsite carrier composite for nitrogen removal and purification of aquaculture wastewater

[0085] A method for denitrification and purification of aquaculture wastewater, wherein the preparation method of the multi-strain-ceramsite carrier complex is specifically as follows:

[0086] Cellulomonas flavigena was cultured in liquid fermentation alone using modified CMC medium; Bacillus subtilis was cultured in liquid fermentation alone using modified LB medium; Bacillus licheniformis was cultured in liquid fermentation alone using high-density fermentation medium; Leuconostoc mesenteroides was cultured in liquid fermentation alone using modified MRS medium; Rhodopseudomonas sphaeroides was cultured in liquid fermentation alone using photosynthetic bacteria basal medium; Rhodopseudomonas palustris was cultured in liquid fermentation alone using optimized photosynthetic bacteria medium; Pediococcus pentasaceus was cultured in liquid fermentation alone using high-density seed medium; and Paracoccus denitrification was cultured in liquid fermentation alone. *Denitrificans* were cultured alone in broth medium for liquid fermentation under the same conditions as in Examples 1, 2, 3, 4, 5, 6, and 7 above. The OD600 nm values ​​were measured to be 0.5-1.5, 1.0-2.0, 1.0-2.0, 0.8-1.5, 1.0-2.0, 1.0-2.0, 0.6-1.2, and 1.0-1.8, respectively. Then, according to the following weight percentages, *Cellulomonas flavigena* 20%, *Bacillus subtilis* 15%, *Bacillus licheniformis* 25%, *Leuconostoc mesenteroides* 10%, and *Rhodopseudomonas* 10% were added. The fermentation broth was prepared by centrifugation, removing the fermentation liquid, and diluting it to a concentration ≥1×10⁻⁶. The resulting bacteria were: 10% *Rhodopseudomonas palustris*, 5% *Pediococcus pentosaceus*, 10% *Paracoccus denitrificans*, and 5% *Sphaeroides*. 9 CFU / mL bacterial suspension was mixed with carrier material (8 strains were prepared according to the volume ratio of ceramsite carrier and bacterial suspension to carrier mass as in Examples 1-8), solidified and dried to obtain a multi-strain-ceramsite carrier complex for denitrification and purification of aquaculture wastewater, with a total viable count ≥1×10⁻⁶. 9 CFU / g.

[0087] Example 10: A method for denitrification and purification of aquaculture wastewater

[0088] The specific preparation method of the multi-strain-ceramsite carrier complex is as follows: Cellulomonas flavigena is cultured individually in modified CMC medium via liquid fermentation; Bacillus subtilis is cultured individually in modified LB medium via liquid fermentation; Bacillus licheniformis is cultured individually in high-density fermentation medium via liquid fermentation; Leuconostoc mesenteroides is cultured individually in modified MRS medium via liquid fermentation; Rhodopseudomonas sphaeroides is cultured individually in photosynthetic bacteria basal medium via liquid fermentation; Rhodopseudomonas palustris is cultured individually in optimized photosynthetic bacteria medium via liquid fermentation; Pediococcus pentasaceus is cultured individually in high-density seed medium via liquid fermentation; and Paracoccus denitrification is cultured individually via liquid fermentation. *Denitrificans* were cultured alone in broth medium for liquid fermentation under the same conditions as in Examples 1, 2, 3, 4, 5, 6, and 7 above. The OD600 nm values ​​were measured to be 0.5-1.5, 1.0-2.0, 1.0-2.0, 0.8-1.5, 1.0-2.0, 1.0-2.0, 0.6-1.2, 1.0-1.8, 1.8-2.2, and 1.5-1.8, respectively. Then, according to the following weight percentages, *Cellulomonas flavigena* 15%, *Bacillus subtilis* 20%, *Bacillus licheniformis* 20%, *Leuconostoc mesenteroides* 10%, and *Rhodopseudomonas* 10% were added. The fermentation broth was prepared by centrifugation, removing the fermentation liquid, and diluting it to a concentration ≥1×10⁻⁶. The resulting bacteria were: 10% *Rhodopseudomonas palustris*, 10% *Pediococcus pentosaceus*, and 5% *Paracoccus denitrificans*. 9 CFU / mL bacterial suspension was mixed with carrier material (8 strains were prepared according to the volume ratio of ceramsite carrier and bacterial suspension to carrier mass as in Examples 1-8), solidified and dried to obtain a multi-strain-ceramsite carrier complex for denitrification and purification of aquaculture wastewater, with a total viable count ≥1×10⁻⁶. 9 -1×1011 CFU / g.

[0089] Example 11: A method for denitrification and purification of aquaculture wastewater.

[0090] The specific preparation method of the multi-strain-ceramsite carrier complex is as follows: Cellulomonas flavigena is cultured individually in modified CMC medium via liquid fermentation; Bacillus subtilis is cultured individually in modified LB medium via liquid fermentation; Bacillus licheniformis is cultured individually in high-density fermentation medium via liquid fermentation; Leuconostoc mesenteroides is cultured individually in modified MRS medium via liquid fermentation; Rhodopseudomonas sphaeroides is cultured individually in photosynthetic bacteria basal medium via liquid fermentation; Rhodopseudomonas palustris is cultured individually in optimized photosynthetic bacteria medium via liquid fermentation; Pediococcus pentasaceus is cultured individually in high-density seed medium via liquid fermentation; and Paracoccus denitrification is cultured individually via liquid fermentation. *Denitrificans* were cultured alone in broth medium for liquid fermentation under the same conditions as in Examples 1, 2, 3, 4, 5, 6, and 7 above. The OD600 nm values ​​were measured to be 0.5-1.5, 1.0-2.0, 1.0-2.0, 0.8-1.5, 1.0-2.0, 1.0-2.0, 0.6-1.2, 1.0-1.8, 1.8-2.2, and 1.5-1.8, respectively. Then, according to the following weight percentages, *Cellulomonas flavigena* 15%, *Bacillus subtilis* 25%, *Bacillus licheniformis* 15%, *Leuconostoc mesenteroides* 15%, and *Rhodopseudomonas* 15% were added. The fermentation broth consisted of 7% *Rhodopseudomonas palustris*, 8% *Pediococcus pentosaceus*, 10% *Paracoccus denitrificans*, and 5% *Sphaeroides*. After centrifugation, the fermentation broth was removed and diluted to a concentration ≥1×10⁻⁶. 9CFU / mL bacterial suspension was mixed with carrier material (8 strains were prepared according to the volume ratio of ceramsite carrier and bacterial suspension to carrier mass as in Examples 1-8), solidified and dried to obtain a multi-strain-ceramsite carrier complex for denitrification and purification of aquaculture wastewater, with a total viable count ≥1×10⁻⁶. 9 -1×10 11 CFU / g.

[0091] Before the bacterial strain-carrier complex prepared in Examples 1-11 was added to the wastewater, the bacterial strain was activated. The activation solutions included Activation Solution I and Activation Solution II. Activation Solution I consisted of Bacillus licheniformis and Bacillus subtilis, while Activation Solution II consisted of Flavobacterium xanthogenes, Leuconostoc mesenteroides, Rhodopseudomonas spheroidosa, Rhodopseudomonas palustris, Pediococcus pentosaceus, and Paracoccus denitrificans. Activation Solution I was composed of sterile water, 0.3% glucose, and 0.4% peptone. Activation Solution II consisted of 0.3% glucose, 0.4% peptone, and 0.3% sodium acetate. The mixture consists of 0.5% ammonium chloride, 0.5% sodium thiomethylcellulose, 0.1% potassium dihydrogen phosphate, 0.2% potassium nitrate, 0.15% yeast extract, and 0.2% sucrose. The strain-ceramsite carrier complex is mixed with the activation solution at a mass-to-volume ratio of 1:10 and poured into a transparent plastic container, ensuring that the carrier is completely submerged. The total proportion of the carrier should not exceed 1 / 3 of the volume of the mixed solution. Activation takes 8-10 hours. The dosage of the multi-strain-ceramsite carrier complex is 150-200g per cubic meter of wastewater, and the strain-carrier complex is added in layers.

[0092] The bacterial strain-carrier complexes prepared in Examples 1-11 are all suitable for denitrification and purification equipment for aquaculture wastewater. When this multi-strain-ceramsite carrier complex is used for static denitrification and purification of aquaculture wastewater, a layered delivery method is adopted to match the environmental conditions at different depths of the water body. To ensure the activity of the strains and the denitrification effect, the temperature of the wastewater needs to be controlled in the range of 22℃-36℃, the pH value needs to be adjusted in the range of 6.5-8.2, and the C / N ratio of the wastewater needs to be adjusted to 5:2-8:1. The cover should be made of light-transmitting material or a 620-650 LED array should be arranged around the equipment with a light intensity ≥5000 lux and a daily light exposure time of 8:00-18:00.

[0093] Experimental Example 1: Antagonism Detection

[0094] The eight strains of bacteria-ceramsite carrier complexes for wastewater treatment fermentation purification prepared in Examples 1-8 were each diluted to 1×10⁻⁶. 8 cfu / mL bacterial suspension.

[0095] First, perforated Xinhua brand filter paper was prepared, and then packaged into several vaccine vials for sterilization; LB culture plates were prepared; the bacterial culture solution was diluted to 1×10⁻⁶. 8Add the CFU / mL bacterial suspension to the sterilized vaccine vials, allowing the bacterial suspension to soak the filter paper. Use one vial of filter paper per bacterial suspension and label it. Take 0.1 mL of each bacterial suspension and spread it evenly on a plate. Spread each bacterial suspension on two plates. Using sterile forceps, place filter paper soaked in the suspension of another bacterial strain onto the plate. Place six filter paper pieces soaked in different bacterial suspensions on each plate and label them. Let stand for 30 minutes and incubate at 37°C for 24 hours. Observe whether inhibition zones appear. If they appear, it indicates that there is an antagonistic effect between the two bacterial strains. The results are shown in Table 1.

[0096] Table 1 Results of antagonistic tests on different strains

[0097]

[0098] Note: " / " indicates no reaction between the same bacterial strain; "-" indicates no inhibition zone between the two strains.

[0099] As shown in the table above, there was no antagonistic reaction between any two strains in the antagonism test.

[0100] Experimental Example 2: Detection of the Clear Zone on a Protein Plate

[0101] Eight strains of bacteria prepared in Examples 1-8 for denitrification and purification of aquaculture wastewater using a multi-strain-ceramsite carrier complex were dissolved in sterile water at a ratio of 1g:100mL. 10μL of each strain was inoculated onto milk agar plates using the streak plate method and incubated at 37℃ for 24h. The presence or absence of a clear zone around the colony was observed. A positive result was defined as a clear zone around the colony, while a negative result was defined as the absence of a clear zone. The positive strains were re-inoculated onto milk agar plates for 48h, and the ratio of the diameter of the hydrolyzed clear zone to the colony diameter was measured. The results are shown in Table 2.

[0102] The results in Table 2 show that Examples 1, 2, and 3 exhibited a strong ability to break down proteins.

[0103] Experimental Example 3: Detection of the Transparent Zone on Starch Plates

[0104] Eight strains of bacteria prepared in Examples 1-8 for denitrification and purification of aquaculture wastewater using a multi-strain-ceramsite carrier complex were dissolved in sterile water at a ratio of 1g:100mL. 10μL of each strain was inoculated onto starch slurry plates using the streak plate method and incubated at 37℃ for 24h. Then, 0.8mL of a 2% iodine tincture solution (pre-diluted 15 times with distilled water) was added to each plate. The plate was rotated to cover the entire surface with iodine solution, and allowed to stand for 1min. The presence of a colorless transparent zone around the colony was observed. A positive result was indicated by the appearance of a transparent zone, while a negative result was indicated by the absence of a transparent zone. The positive strains were then inoculated again onto starch slurry plates and cultured using the same procedure. The ratio of the diameter of the hydrolyzed transparent zone to the colony diameter was measured, and the results are shown in Table 2.

[0105] The results in Table 2 show that Examples 1, 2, and 3 exhibited a strong ability to decompose starch.

[0106] Experimental Example 4: Determination of Fat Hydrolysis Plate Detection and Oil Degradation Rate

[0107] The eight strains of multi-strain-ceramsite carrier complexes for denitrification and purification of aquaculture wastewater prepared in Examples 1-8 were dissolved in sterile water at a ratio of 1g:100mL. 10μL of each strain was inoculated onto oil culture medium plates using the streak plate method and incubated at 37℃ for 24h. The results were observed. If the colonies were red and there were red spots where the colonies grew, it indicated that the fat had been hydrolyzed, and the result was considered positive. Otherwise, it was considered negative.

[0108] The strains that tested positive for the above-mentioned oil culture medium were used to pick colonies with an inoculation loop and transferred to Erlenmeyer flasks containing 100 ml of nutrient broth medium. The flasks were then shaken at 37 ℃ and 180 r / min for 24 h. The cultures were then inoculated again with a degradation medium composed of olive oil at a concentration of 10%, and fermented at 37 ℃ and 180 r / min for 2 days before the oil degradation rate was determined.

[0109] The oil content was determined according to the method described by Qin Huaming (2003). The oil degradation rate was calculated according to the method described by Meng Zhuoni (2019). The results are shown in Table 2.

[0110] Table 2. Results of tests on the degradation ability of different strains of oil, starch, and protein.

[0111]

[0112] The results in Table 2 show that Examples 2, 3, and 6 have a certain ability to degrade oils, but Example 2 shows a stronger ability to decompose oils.

[0113] Experiment 5: Denitrification and Purification Experiment of Aquaculture Wastewater

[0114] The wastewater came from a small-scale pig farm in Chongzuo City, which uses a process of cleaning manure by soaking it in water.

[0115] Before adding the multi-strain-ceramsite carrier complex to the wastewater, the strains must be activated. The strain-ceramsite carrier complex and the activation solution are mixed at a ratio of 1:10 (mass-volume ratio). The dosage of the multi-strain-ceramsite carrier complex is 150-200g per cubic meter of wastewater, and it is added in layers. The wastewater temperature is controlled within the range of 20℃-35℃, the pH value is adjusted within the range of 6.5-8.5, and the C / N ratio of the wastewater is adjusted to 5:2-8:1. The multi-strain-ceramsite carrier complex is added to, but not limited to, a 2-meter deep sewage pond. The multi-strain-carrier complex is added in layers, in the bottom, middle and top layers. First, the submerged strains of Rhodopseudomonas palustris, Rhodopseudomonas spheroidae, and Paracoccus denitrifying are added to the bottom layer of the low dissolved oxygen / anaerobic zone at 1.5-2 meters. Then, the suspended strains of Pediococcus pentosaceus and Leuconostoc mesenteroides are added to the middle layer of the medium-low dissolved oxygen zone at 0.5-1.5 meters. Finally, the floating strains of Bacillus subtilis, Bacillus licheniformis, and Fibromosporium xanthogenes are added to the surface layer of the high dissolved oxygen zone at 0-0.5 meters.

[0116] The experiment included a blank control group (CK) containing only aquaculture wastewater; Experiment 1 consisted of aquaculture wastewater plus the multi-strain-ceramsite carrier complex from Example 9; Experiment 2 consisted of aquaculture wastewater plus the multi-strain-ceramsite carrier complex from Example 10; and Experiment 3 consisted of aquaculture wastewater plus the multi-strain-ceramsite carrier complex from Example 11. Each treatment group was repeated three times.

[0117] The bacterial agent was applied once every 3 days for a total of 12 days. Sampling was conducted before the start of the experiment and again on day 12. The main indicators detected were total nitrogen (TN), ammonia nitrogen (NH4⁺-N), and COD. The determination of total nitrogen (TN) content followed HJ626-2012.

[0118] The determination of ammonia nitrogen (NH4⁺-N) content was performed according to HJ525-2009; the determination of COD content was performed according to HJ828-2017, and the results are shown in […]. Figure 1 .

[0119] Depend on Figure 1It can be seen that the strain-ceramsite carrier complex in Example 10 exhibited the best degradation effect. The total nitrogen (TN) degradation rate was 89.2%, compared to 28.1% in the blank control group, representing a 3.17-fold increase; the ammonia nitrogen (NH4⁺-N) degradation rate was 91.2%, compared to 30.3% in the blank control group, representing a 3.0-fold increase; and the COD degradation rate was 82.2%, compared to 23.2% in the blank control group, representing a 3.54-fold increase. These data indicate that the multi-strain-ceramsite carrier complex has a superior effect on nitrogen removal and purification of aquaculture wastewater.

[0120] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A multi-strain-ceramic carrier complex for denitrification of aquaculture wastewater, characterized by: The multi-strain-ceramic carrier complex comprises, in percentage by mass, Cellulomonas flavigena 15%-20%, Bacillus subtilis 15%-25%, Bacillus licheniformis 15%-20%, Leuconostoc mesenteroides 10%-15%, Rhodopseudomonas sphaeroides 7%-10%, Rhodopseudomonas palustris 5%-10%, Pediococcus pentasaceus 10%, Paracoccus denitrificans 5%; the total bacteria amount of the multi-strain-ceramic carrier complex is ≥1×10 9 -1×10 11 CFU / g.

2. The multi-strain-ceramic carrier complex for denitrification of aquaculture wastewater according to claim 1, characterized in that: The preservation number of Cellulomonas flavigena is BMZ134560, the preservation number of Bacillus subtilis is BMZ339677, the preservation number of Bacillus licheniformis is BMZ137481, the preservation number of Leuconostoc mesenteroides is CGMCC 1.2138, the preservation number of Rhodopseudomonas sphaeroides is CGMCC 1.2182, the preservation number of Rhodopseudomonas palustris is BMZ121828, the preservation number of Pediococcus pentasaceus is BMZ123303, and the preservation number of Paracoccus denitrificans is BMZ010503.

3. A method for preparing the multi-strain-ceramsite carrier composite for denitrification and purification of aquaculture wastewater as described in claim 1, characterized in that: Specifically, Cellulomonas flavigena is cultured in a modified CMC medium for liquid fermentation, Bacillus subtilis is cultured in a modified LB medium for liquid fermentation, Bacillus licheniformis is cultured in a high-density fermentation medium for liquid fermentation, Leuconostoc mesenteroides is cultured in a modified MRS medium for liquid fermentation, Rhodopseudomonas sphaeroides is cultured in a photosynthetic bacteria basic medium for liquid fermentation, Rhodopseudomonas palustris is cultured in an optimized photosynthetic bacteria medium for liquid fermentation, Pediococcus pentasaceus is cultured in a high-density seed medium for liquid fermentation, and Paracoccus denitrificans is cultured in a broth medium for liquid fermentation. The effective viable cell count is detected, the fermentation broth is removed after centrifugation, and is diluted to a concentration of ≥1×10 9 CFU / mL, mixed with a carrier material, solidified and dried to obtain a multi-strain-tollite carrier compound for breeding and purifying denitrified sewage. 9 -1×10 11 CFU / g.

4. The production method according to claim 3, characterized by: The 8 strains are activated before fermentation culture, and Cellulomonas flavigena, Bacillus subtilis, Bacillus licheniformis, Leuconostoc mesenteroides, Rhodopseudomonas sphaeroides, Rhodopseudomonas palustris, Pediococcus pentasaceus and Paracoccus denitrificans are activated separately, and the activated bacterial liquid is sequentially inoculated into 10%, 20%, 50% and 100% of sterilized aquaculture wastewater for domestication culture, and finally inoculated into the corresponding culture medium for culture, serving as seed bacteria preservation.

5. The production method according to claim 3, wherein The sterilized aquaculture wastewater is obtained by the bubble manure cleaning process; the aquaculture wastewater includes but is not limited to the wastewater of pig farms using the bubble manure cleaning process or the dry manure cleaning process, which contains urine, feces and barn flushing water, and does not contain disinfectants, sodium hydroxide and other drugs that are not conducive to the growth of bacterial agents, and is the wastewater discharged within one week.

6. The production method according to claim 3, wherein The carrier material is ceramic; the ceramic is floating ceramic and / or suspended ceramic and / or submerged ceramic; the carrier material can increase the air permeability and compatibility, and the surface is easy to form a biofilm, which is beneficial to the attachment and metabolic activity of bacteria.

7. The production method according to claim 6, wherein The yellow-producing Cellulomonas and the floating ceramic carrier are mixed to form a strain-carrier complex in a ratio of 1:1 (L / kg) of the volume of the bacterial solution to the mass of the carrier; the Bacillus subtilis and the floating ceramic carrier are mixed to form a strain-carrier complex in a ratio of 1:0.2 (L / kg) of the volume of the bacterial solution to the mass of the carrier; the Bacillus licheniformis and the floating ceramic carrier are mixed to form a strain-carrier complex in a ratio of 1:0.2 (L / kg) of the volume of the bacterial solution to the mass of the carrier; the Leuconostoc mesenteroides and the suspended ceramic carrier are mixed to form a strain-carrier complex in a ratio of 1:0.2 (L / kg) of the volume of the bacterial solution to the mass of the carrier; the Rhodopseudomonas sphaeroides and the submerged ceramic carrier are mixed to form a strain-carrier complex in a ratio of 1:0.2 (L / kg) of the volume of the bacterial solution to the mass of the carrier; the Rhodopseudomonas palustris and the submerged ceramic carrier are mixed to form a strain-carrier complex in a ratio of 1:0.2 (L / kg) of the volume of the bacterial solution to the mass of the carrier; the Pediococcus pentosaceus and the suspended ceramic carrier are mixed to form a strain-carrier complex in a ratio of 1:0.2 (L / kg) of the volume of the bacterial solution to the mass of the carrier; and the Paracoccus denitrificans and the submerged ceramic carrier are mixed to form a strain-carrier complex in a ratio of 1:2 (L / kg) of the volume of the bacterial solution to the mass of the carrier.

8. A method for treating aquaculture wastewater to remove nitrogen, characterized by, The multi-strain ceramic carrier complex prepared in claim 3 is put into, but not limited to, a 2-meter-deep sewage pool. The multi-strain carrier complex is added in layers, and is added in the bottom layer, the middle layer, and the surface layer in sequence. First, the Rhodopseudomonas palustris, the Rhodopseudomonas sphaeroides, and the Paracoccus denitrificans submerged strain-carrier complex are added to the bottom layer of the low-oxygen / anaerobic zone water at a depth of 1.5-2 meters. Then, the Leuconostoc mesenteroides and the Pediococcus pentosaceus suspended strain-carrier complex are added to the middle layer of the low-oxygen zone water at a depth of 0.5-1.5 meters. Finally, the Bacillus subtilis, the Bacillus licheniformis, and the yellow-producing Cellulomonas floating strain-carrier complex are added to the surface layer of the high-oxygen zone water at a depth of 0-0.5 meters.

9. The treatment method of claim 8, wherein, The multi-strain ceramic carrier complex is activated before being put into sewage. The activation solution includes activation solution I and activation solution II. The activation solution I is the activation solution of the Bacillus licheniformis and the Bacillus subtilis, and the activation solution II is the activation solution of the yellow-producing Cellulomonas, the Leuconostoc mesenteroides, the Rhodopseudomonas sphaeroides, the Rhodopseudomonas palustris, the Pediococcus pentosaceus, and the Paracoccus denitrificans. The activation solution I is composed of sterile water, 0.3% glucose, and 0.4% protein peptone. The activation solution II is composed of 0.3% glucose, 0.4% protein peptone, 0.3% sodium acetate, 0.5% ammonium chloride, 0.5% sodium methyl cellulose, 0.1% potassium dihydrogen phosphate, 0.2% potassium nitrate, 0.15% yeast extract, and 0.2% sucrose. The strain-carrier complex of the strain and the activation solution are mixed in a ratio of 1:10 by mass and volume, poured into a transparent plastic container, and the carrier is completely immersed, with the total proportion of the carrier not exceeding 1 / 3 of the volume of the mixed solution. The activation is performed for 8-10 hours. The multi-strain-ceramic carrier complex is added in an amount of 150-200g per cubic meter of sewage, and the strain-carrier complex is added in layers.

10. The treatment method of claim 8, wherein, The multi-strain-ceramic carrier complex is suitable for aquaculture sewage denitrification purification equipment, and is used for static denitrification purification treatment of aquaculture sewage. In order to match the environmental conditions at different depths of the water body, the multi-strain-ceramic carrier complex is added in layers. In order to ensure the activity of the strain and the denitrification effect, the temperature of the sewage needs to be controlled in the range of 22-36 DEG C, the pH value needs to be controlled in the range of 6.5-8.2, the C / N of the sewage needs to be adjusted to 5:2-8:1, the cover thereof should be a light-transmitting material or a 620-650 LED array is arranged around the equipment, the light intensity is greater than or equal to 5000 lux, and the daily light time is 8:00-18:00.

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