A method for treating wastewater from industrialized aquaculture

Abstract

This invention belongs to the field of wastewater treatment technology, specifically relating to a method for treating wastewater from industrialized aquaculture. This invention combines physical, biological, and chemical treatment methods, enabling efficient wastewater treatment in a short time, reducing the footprint and operating costs of treatment equipment, and exhibiting high economic efficiency and practicality. The combined use of Spirulina with Bacillus licheniformis, Bacillus subtilis, and Micrococcus luteus forms a stable algae-bacteria symbiotic system in the aquatic environment, accelerating the removal of nitrogen and phosphorus from the aquaculture wastewater and effectively reducing the chemical oxygen demand (COD). After treatment using this method, the wastewater reuse rate is no less than 80%, and the treated wastewater quality meets national discharge standards.

Description

Technical Field

[0001] This invention belongs to the field of wastewater treatment technology, and specifically relates to a method for treating wastewater from factory farming. Background Technology

[0002] With the rapid development of aquaculture, factory farming has gained widespread attention due to its high efficiency and intensive nature. However, this model also presents challenges in treating aquaculture wastewater. Factory farming wastewater contains large amounts of pollutants such as uneaten feed, feces, ammonia nitrogen, nitrite, and nitrate. Direct discharge of such wastewater would cause serious environmental pollution. Therefore, developing effective wastewater treatment methods is of paramount importance.

[0003] Existing factory-scale recirculating aquaculture systems typically employ sedimentation or vertical filters for initial filtration. While sedimentation facilitates solid-liquid separation, it is time-consuming, requires a large sedimentation tank area, and impacts filtration efficiency. Furthermore, static sedimentation is susceptible to environmental influences, leading to re-mixing of solids and liquids during effluent discharge, affecting the filtration quality of the effluent. Vertical filters, while effective in the short term, accumulate impurities between the screens over long-term operation, requiring frequent shutdowns for cleaning, wasting significant manpower, and reducing filtration efficiency. Biological treatment methods such as constructed wetlands and biofilters are also used in effluent treatment, but they have limitations. For example, constructed wetlands require large areas, and their treatment efficiency is significantly affected by seasons and climate; biofilters are less effective at removing COD. Summary of the Invention

[0004] The purpose of this invention is to provide a method for treating wastewater from industrialized aquaculture, thereby achieving efficient recycling of aquaculture wastewater.

[0005] This invention provides a method for treating wastewater from industrialized aquaculture, comprising the following steps:

[0006] The aquaculture wastewater is introduced into a sedimentation tank for sedimentation to obtain settled wastewater. The sedimentation tank contains water-blocking facilities, and the sedimentation time is 1 to 3 hours.

[0007] The settled effluent is introduced into an ecological purification pond for 2-4 hours to obtain primary ecologically purified effluent. Submerged, floating-leaved, and emergent plants are planted in the ecological purification pond, and silver carp, catfish, crucian carp, freshwater shrimp, snails, and freshwater mussels are stocked. The ecologically purified effluent is then introduced into an aeration tank for disinfection. The aeration tank is equipped with suspended biological packing columns and evenly distributed microporous aeration heads at the bottom. The density of the biological packing columns is 5000-8000 columns / acre, and the density of the microporous aeration heads is 220-250 heads / acre. The biological packing columns consist of packing material and microorganisms. The packing material is one or more of biochar, volcanic rock, and ceramsite, and the microorganisms are Spirulina, Bacillus subtilis, Bacillus licheniformis, and Micrococcus luteus.

[0008] Preferably, the volume ratio of the sedimentation tank, the ecological purification tank, and the aeration tank is 200~300:350~450:900~1200; the depth of the sedimentation tank is 2.5m~3.5m, the depth of the ecological purification tank is 1.5m~2.5m, and the depth of the aeration tank is 1m~2m; preferably, the water-blocking device includes a brush and a biological chamber, which are arranged vertically along the water flow direction, with a front-to-back and left-to-right spacing of 30cm~50cm.

[0009] Preferably, the submerged plants include Vallisneria natans and Hydrilla verticillata, the floating-leaved plants include water lilies, and the emergent plants include reeds and cattails; the planting area of ​​the submerged plants accounts for 20% of the ecological purification pond, the planting area of ​​the floating-leaved plants accounts for 20% of the ecological purification pond, and the planting area of ​​the emergent plants accounts for 20% of the ecological purification pond.

[0010] Preferably, the stocking density is 50 to 100 silver carp per mu, 30 to 50 catfish per mu, 100 to 200 crucian carp per mu, 10 to 20 kg of freshwater shrimp per mu, 150 to 300 kg of snails per mu, and 40 to 50 kg of freshwater mussels per mu.

[0011] Preferably, the mass ratio of spirulina to packing material is 0.2~2:1; the mass ratio of Bacillus subtilis, Bacillus licheniformis, and Micrococcus luteus is 2~5:1~3:1~2; the total mass ratio of Bacillus subtilis, Bacillus licheniformis, and Micrococcus luteus to packing material is 0.01~0.02:1; and the number of viable bacteria per gram of bacteria is ≥5~10×10⁻⁶. 8 The present invention does not have any particular limitation on the source of Bacillus subtilis, Bacillus licheniformis and Micrococcus luteus, and conventional commercially available products are all acceptable.

[0012] Preferably, the distance between the top of the aeration head and the bottom of the biological packing column is 1m.

[0013] Preferably, the biological packing column is a ring structure with a height of 1.5m to 2.5m, an inner diameter of 5 to 8cm, and an outer diameter of 7 to 10cm.

[0014] Preferably, the specific surface area of ​​the biological packing column is 2.5 mm². 2 / g~4mm 2 / g.

[0015] Preferably, the disinfection process takes 30 to 60 minutes.

[0016] The beneficial effects of this invention are:

[0017] This invention first uses sedimentation in the effluent, effectively removing most suspended solids and large particulate impurities, significantly reducing turbidity and creating favorable conditions for subsequent ecological purification treatment. The water-blocking facilities in the sedimentation tank increase water flow and residence time, allowing suspended solids more time to settle, improving sedimentation efficiency and further enhancing the pretreatment effect. Through this preliminary treatment in the sedimentation tank, this invention reduces the pollutant load entering the ecological purification tank, lowers the treatment pressure on the ecological purification tank, extends its service life, and improves the overall operational efficiency and stability of the effluent treatment system.

[0018] Planting submerged, floating-leaved, and emergent plants in ecological purification ponds creates a multi-layered ecological purification system. Stocked aquatic animals such as silver carp, catfish, shrimp, snails, and clams form a synergistic biological purification system with the plants. Submerged plants absorb nutrients from the water and inhibit excessive algae growth; floating-leaved plants block sunlight, lower water temperature, and reduce algae reproduction; emergent plants absorb pollutants through their roots and provide habitats for aquatic animals; silver carp and catfish feed on plankton, effectively controlling plankton levels and reducing eutrophication; and benthic animals such as shrimp, snails, and clams further purify the water by consuming organic matter and algae in the sediment. Their activities also promote the release and diffusion of pollutants in the sediment, enhancing the water's self-purification capacity.

[0019] The aeration tank is equipped with uniformly distributed biological packing columns. These high-surface-area packing materials provide numerous attachment sites for microorganisms, significantly increasing the contact area between the microorganisms and the water. This not only facilitates the adsorption and decomposition of organic matter and nutrients in the water by microorganisms but also improves the purification efficiency of the entire treatment system. The biological packing columns employ a ring structure, which further optimizes the packing layout and ensures that water flow can fully penetrate the packing, thereby maximizing contact efficiency.

[0020] The biological packing column is composed of one or more of biochar, volcanic rock, and ceramsite, materials with good adsorption properties and biocompatibility. Microorganisms attached to the packing include Spirulina, Bacillus subtilis, Bacillus licheniformis, and Micrococcus luteus. These microorganisms form a biofilm on the packing surface, efficiently decomposing organic matter and nutrients in the water. Spirulina effectively removes inorganic nitrogen (such as ammonia nitrogen, nitrite, and nitrate) and inorganic phosphorus (such as phosphate) from the effluent. When Spirulina is co-cultured with Bacillus licheniformis, Bacillus subtilis, and Micrococcus luteus, a stable algae-microbe symbiotic system can be formed in the aquatic environment. This symbiotic system effectively promotes the growth of Spirulina and accelerates the removal of nitrogen and phosphorus from the aquaculture effluent. Furthermore, Spirulina also has a good enrichment effect on certain heavy metals. When Micrococcus luteus is co-cultured with Bacillus licheniformis and Bacillus subtilis, the ecological purification effect can be further enhanced, effectively increasing the chemical oxygen demand (COD) and ammonia nitrogen (NH3) in the effluent. 4+ -N), nitrate (NO3) - The removal rate of -N) improves the ability to degrade recalcitrant organic matter.

[0021] This invention places microporous aerators at the bottom of the pool. The numerous bubbles generated by these aerators rise and come into full contact with the water, increasing the dissolved oxygen content. This high dissolved oxygen environment is beneficial to the metabolic activities of microorganisms, particularly nitrifying and denitrifying bacteria. These microorganisms can convert ammonia nitrogen in the water into nitrates, and then, through denitrification, convert the nitrates back into nitrogen gas, releasing it into the atmosphere, thus effectively removing nitrogen from the water. Simultaneously, the aeration process also promotes the oxidation and precipitation of phosphorus in the water, further reducing the phosphorus content.

[0022] A 1-meter distance is maintained between the top of the aeration head and the bottom of the biological packing column. This design not only prevents the aeration head from being blocked by the packing but also ensures that air bubbles can fully penetrate the packing layer, improving aeration efficiency. The aeration tank design takes into account the uniform distribution of water flow and the cutting effect of air bubbles, reducing water flow short-circuiting and dead zones, and improving the stability and reliability of the entire system.

[0023] This invention combines physical, biological, and chemical treatment methods, enabling efficient treatment of effluent in a short time while reducing the footprint and operating costs of treatment equipment, thus offering high economic efficiency and practicality. After treatment using this method, the effluent reuse rate is no less than 80%, and the treated effluent quality meets national discharge standards. Detailed Implementation

[0024] To further illustrate the present invention, the following detailed description of a method for treating wastewater from industrialized aquaculture provided by the present invention is provided in conjunction with embodiments, but these descriptions should not be construed as limiting the scope of protection of the present invention.

[0025] Unless otherwise specified, all substances used in the embodiments of this invention are commercially available products.

[0026] Example 1

[0027] Set up a sedimentation tank: arrange brushes and biological chambers vertically along the water flow direction, with a spacing of 50cm in all directions.

[0028] The aquaculture wastewater is introduced into a sedimentation tank with a water-blocking device and allowed to settle for 2 hours to obtain the settled wastewater.

[0029] The settled effluent was introduced into an ecological purification pond, where 20% of the total area was planted with Vallisneria natans, 20% with water lilies, and 20% with calamus. Each acre was stocked with 60 silver carp, 40 catfish, 120 crucian carp, 15 kg of freshwater shrimp, 200 kg of snails, and 40 kg of freshwater mussels. After 4 hours of purification, the ecologically purified effluent was obtained.

[0030] The purified effluent was introduced into an aeration tank, which was 4m deep and contained evenly distributed biological packing columns at a density of 6000 columns / acre. At the bottom of the tank were evenly distributed microporous aeration heads at a density of 220 heads / acre, with a 1m gap between the top of the aeration heads and the bottom of the biological packing columns. The biological packing columns were ring-shaped, 2m high, with an inner diameter of 5cm and an outer diameter of 8cm. The ring structure was filled with a mixture of biochar, volcanic rock, and ceramsite in a 1:1:1 mass ratio. Spirulina and a compound bacterial agent (a mixture of Bacillus subtilis, Bacillus licheniformis, and Micrococcus luteus in a 2:1:1 mass ratio) were attached to the packing. The mass ratio of spirulina to packing was 0.5:1, and the mass ratio of the compound bacterial agent to packing was 0.01:1. After 3 hours of aeration, the tank was disinfected with sodium hypochlorite for 60 minutes.

[0031] Example 2

[0032] Set up a sedimentation tank: arrange brushes and biological chambers vertically along the water flow direction, with a spacing of 50cm in all directions.

[0033] The aquaculture wastewater is introduced into a sedimentation tank with a water-blocking device and allowed to settle for 2 hours to obtain the settled wastewater.

[0034] The settled effluent was introduced into an ecological purification pond, where 20% of the total area was planted with Vallisneria natans, 20% with water lilies, and 20% with calamus. Each acre was stocked with 60 silver carp, 40 catfish, 120 crucian carp, 15 kg of freshwater shrimp, 200 kg of snails, and 40 kg of freshwater mussels. After 4 hours of purification, the ecologically purified effluent was obtained.

[0035] The purified effluent was introduced into an aeration tank, which was 4m deep. The tank contained evenly distributed biological packing columns at a density of 6000 columns / acre, and evenly distributed microporous aeration heads at a density of 220 heads / acre at the bottom. The distance between the top of the aeration heads and the bottom of the biological packing columns was 1m. The biological packing columns were ring-shaped, 2m high, with an inner diameter of 5cm and an outer diameter of 8cm. The ring structure was filled with a mixture of biochar, volcanic rock, and ceramsite in a 1:1:1 mass ratio. Spirulina and a compound bacterial agent (a mixture of Bacillus subtilis, Bacillus licheniformis, and Micrococcus luteus in a 4:3:2 mass ratio) were attached to the packing. The mass ratio of spirulina to packing was 0.5:1, and the mass ratio of the compound bacterial agent to packing was 0.01:1. After 3 hours of aeration, the tank was disinfected with sodium hypochlorite for 60 minutes.

[0036] Example 3

[0037] Set up a sedimentation tank: arrange brushes and biological chambers vertically along the water flow direction, with a spacing of 50cm in all directions.

[0038] The aquaculture wastewater is introduced into a sedimentation tank with a water-blocking device and allowed to settle for 2 hours to obtain the settled wastewater.

[0039] The settled effluent was introduced into an ecological purification pond, where 20% of the total area was planted with Vallisneria natans, 20% with water lilies, and 20% with calamus. Each acre was stocked with 60 silver carp, 40 catfish, 120 crucian carp, 15 kg of freshwater shrimp, 200 kg of snails, and 40 kg of freshwater mussels. After 4 hours of purification, the ecologically purified effluent was obtained.

[0040] The purified effluent was introduced into an aeration tank, which was 4m deep and contained evenly distributed biological packing columns at a density of 6000 columns / acre. At the bottom of the tank were evenly distributed microporous aeration heads at a density of 220 heads / acre, with a 1m gap between the top of the aeration heads and the bottom of the biological packing columns. The biological packing columns were ring-shaped, 2m high, with an inner diameter of 5cm and an outer diameter of 8cm. The ring structure was filled with a packing material consisting of biochar, volcanic rock, and ceramsite in a 1:1:1 mass ratio. Spirulina and a compound bacterial agent (a mixture of Bacillus subtilis, Bacillus licheniformis, and Micrococcus luteus in a 3:2:1 mass ratio) were attached to the packing material. The mass ratio of spirulina to packing material was 0.5:1, and the mass ratio of the compound bacterial agent to packing material was 0.01:1. After 3 hours of aeration, the tank was disinfected with sodium hypochlorite for 60 minutes.

[0041] Example 4

[0042] Set up a sedimentation tank: arrange brushes and biological chambers vertically along the water flow direction, with a spacing of 50cm in all directions.

[0043] The aquaculture wastewater is introduced into a sedimentation tank with a water-blocking device and allowed to settle for 2 hours to obtain the settled wastewater.

[0044] The settled effluent was introduced into an ecological purification pond, where 20% of the total area was planted with Vallisneria natans, 20% with water lilies, and 20% with calamus. Each acre was stocked with 60 silver carp, 40 catfish, 120 crucian carp, 15 kg of freshwater shrimp, 200 kg of snails, and 40 kg of freshwater mussels. After 4 hours of purification, the ecologically purified effluent was obtained.

[0045] The purified effluent was introduced into an aeration tank, which was 4m deep and contained evenly distributed biological packing columns at a density of 6000 columns / acre. At the bottom of the tank were evenly distributed microporous aeration heads at a density of 220 heads / acre, with a 1m gap between the top of the aeration heads and the bottom of the biological packing columns. The biological packing columns were ring-shaped, 2m high, with an inner diameter of 5cm and an outer diameter of 8cm. The ring structure was filled with a mixture of biochar, volcanic rock, and ceramsite in a 1:1:1 mass ratio. Spirulina and a compound bacterial agent (a mixture of Bacillus subtilis, Bacillus licheniformis, and Micrococcus luteus in a 5:3:2 mass ratio) were attached to the packing. The mass ratio of spirulina to packing was 0.5:1, and the mass ratio of the compound bacterial agent to packing was 0.01:1. After 3 hours of aeration, the tank was disinfected with sodium hypochlorite for 60 minutes.

[0046] Comparative Example 1

[0047] Set up a sedimentation tank: arrange brushes and biological chambers vertically along the water flow direction, with a spacing of 50cm in all directions.

[0048] The aquaculture wastewater is introduced into a sedimentation tank with a water-blocking device and allowed to settle for 2 hours to obtain the settled wastewater.

[0049] The settled effluent was introduced into an ecological purification pond, where 20% of the total area was planted with Vallisneria natans, 20% with water lilies, and 20% with calamus. Each acre was stocked with 60 silver carp, 40 catfish, 120 crucian carp, 15 kg of freshwater shrimp, 200 kg of snails, and 40 kg of freshwater mussels. After 4 hours of purification, the ecologically purified effluent was obtained.

[0050] The purified effluent was introduced into an aeration tank, which was 4m deep and contained evenly distributed biological packing columns at a density of 6000 columns / acre. At the bottom of the tank were evenly distributed microporous aeration heads at a density of 220 heads / acre, with a 1m gap between the top of the aeration heads and the bottom of the biological packing columns. The biological packing columns were ring-shaped, 2m high, with an inner diameter of 5cm and an outer diameter of 8cm. The ring structure was filled with a mixture of biochar, volcanic rock, and ceramsite in a 1:1:1 mass ratio. A compound microbial agent (Bacillus subtilis, Bacillus licheniformis, and Micrococcus luteus mixed in a 2:1:1 mass ratio) was attached to the packing material, with a mass ratio of the compound microbial agent to the packing material of 0.01:1. After 3 hours of aeration, the tank was disinfected with sodium hypochlorite for 60 minutes.

[0051] Comparative Example 2

[0052] Set up a sedimentation tank: arrange brushes and biological chambers vertically along the water flow direction, with a spacing of 50cm in all directions.

[0053] The aquaculture wastewater is introduced into a sedimentation tank with a water-blocking device and allowed to settle for 2 hours to obtain the settled wastewater.

[0054] The settled effluent was introduced into an ecological purification pond, where 20% of the total area was planted with Vallisneria natans, 20% with water lilies, and 20% with calamus. Each acre was stocked with 60 silver carp, 40 catfish, 120 crucian carp, 15 kg of freshwater shrimp, 200 kg of snails, and 40 kg of freshwater mussels. After 4 hours of purification, the ecologically purified effluent was obtained.

[0055] The purified effluent was introduced into an aeration tank, which was 4m deep and contained evenly distributed biological packing columns at a density of 6000 columns / acre. At the bottom of the tank were evenly distributed microporous aerators at a density of 220 aerators / acre, with a 1m gap between the top of the aerators and the bottom of the biological packing columns. The biological packing columns were ring-shaped, 2m high, with an inner diameter of 5cm and an outer diameter of 8cm. The ring structure was filled with a mixture of biochar, volcanic rock, and ceramsite in a 1:1:1 mass ratio. Spirulina and Micrococcus luteus were attached to the packing material, with a Spirulina to packing material mass ratio of 0.5:1 and Micrococcus luteus to packing material mass ratio of 0.01:1. After 3 hours of aeration, the tank was disinfected with sodium hypochlorite for 60 minutes.

[0056] Comparative Example 3

[0057] Set up a sedimentation tank: arrange brushes and biological chambers vertically along the water flow direction, with a spacing of 50cm in all directions.

[0058] The aquaculture wastewater is introduced into a sedimentation tank with a water-blocking device and allowed to settle for 2 hours to obtain the settled wastewater.

[0059] The settled effluent is introduced into an ecological purification pond. In the ecological purification pond, 60 silver carp, 40 catfish, 120 crucian carp, 15 kg of freshwater shrimp, 200 kg of snails and 40 kg of freshwater mussels are put in per acre. The purification process lasts for 4 hours to obtain the ecologically purified effluent.

[0060] The purified effluent was introduced into an aeration tank, which was 4m deep and contained evenly distributed biological packing columns at a density of 6000 columns / acre. At the bottom of the tank were evenly distributed microporous aeration heads at a density of 220 heads / acre. The distance between the top of the aeration heads and the bottom of the biological packing columns was 1m. The biological packing columns were ring-shaped, 2m high, with an inner diameter of 5cm and an outer diameter of 8cm. The ring structure was filled with a packing material consisting of biochar, volcanic rock, and ceramsite in a mass ratio of 1:1:1. Spirulina and Bacillus licheniformis were attached to the packing material, with a Spirulina to packing material mass ratio of 0.5:1 and a Bacillus licheniformis to packing material mass ratio of 0.01:1. After 3 hours of aeration, the tank was disinfected with sodium hypochlorite for 60 minutes.

[0061] Comparative Example 4

[0062] Set up a sedimentation tank: arrange brushes and biological chambers vertically along the water flow direction, with a spacing of 50cm in all directions.

[0063] The aquaculture wastewater is introduced into a sedimentation tank with a water-blocking device and allowed to settle for 2 hours to obtain the settled wastewater.

[0064] The settled effluent was introduced into an ecological purification pond, where 20% of the total area was planted with Vallisneria natans, 20% with water lilies, and 20% with calamus. Each acre was stocked with 60 silver carp, 40 catfish, 120 crucian carp, 15 kg of freshwater shrimp, 200 kg of snails, and 40 kg of freshwater mussels. After 4 hours of purification, the ecologically purified effluent was obtained.

[0065] The purified effluent was introduced into an aeration tank, which was 4m deep. The tank contained evenly distributed biological packing columns at a density of 6000 columns / acre, and evenly distributed microporous aeration heads at a density of 220 heads / acre at the bottom. The distance between the top of the aeration heads and the bottom of the biological packing columns was 1m. The biological packing columns were ring-shaped, 2m high, with an inner diameter of 5cm and an outer diameter of 8cm. The ring-shaped structure was filled with a mixture of biochar, volcanic rock, and ceramsite in a 1:1:1 mass ratio. Spirulina and a compound bacterial agent (Bacillus subtilis and Bacillus licheniformis mixed in a 2:1 mass ratio) were attached to the packing. The mass ratio of spirulina to packing was 0.5:1, and the mass ratio of the compound bacterial agent to packing was 0.01:1. After 3 hours of aeration, the tank was disinfected with sodium hypochlorite for 60 minutes.

[0066] Comparative Example 5

[0067] Set up a sedimentation tank: arrange brushes and biological chambers vertically along the water flow direction, with a spacing of 50cm in all directions.

[0068] The aquaculture wastewater is introduced into a sedimentation tank with a water-blocking device and allowed to settle for 2 hours to obtain the settled wastewater.

[0069] The settled effluent was introduced into an ecological purification pond, where 20% of the total area was planted with Vallisneria natans, 20% with water lilies, and 20% with calamus. Each acre was stocked with 60 silver carp, 40 catfish, 120 crucian carp, 15 kg of freshwater shrimp, 200 kg of snails, and 40 kg of freshwater mussels. After 4 hours of purification, the ecologically purified effluent was obtained.

[0070] The purified effluent was introduced into an aeration tank, which was 4m deep and contained evenly distributed biological packing columns at a density of 6000 columns / acre. At the bottom of the tank were evenly distributed microporous aeration heads at a density of 220 heads / acre. The distance between the top of the aeration heads and the bottom of the biological packing columns was 1m. The biological packing columns were ring-shaped, 2m high, with an inner diameter of 5cm and an outer diameter of 8cm. The ring structure was filled with a mixture of biochar, volcanic rock, and ceramsite in a mass ratio of 1:1:1. After 3 hours of aeration, the tank was disinfected with sodium hypochlorite for 60 minutes.

[0071] Comparative Example 6

[0072] Set up a sedimentation tank: arrange brushes and biological chambers vertically along the water flow direction, with a spacing of 50cm in all directions.

[0073] The aquaculture wastewater is introduced into a sedimentation tank with a water-blocking device and allowed to settle for 2 hours to obtain the settled wastewater.

[0074] The settled effluent was introduced into an ecological purification pond, where 20% of the total area was planted with Vallisneria natans, 20% with water lilies, and 20% with calamus. Each acre was stocked with 60 silver carp, 40 catfish, 120 crucian carp, 15 kg of freshwater shrimp, 200 kg of snails, and 40 kg of freshwater mussels. After 4 hours of purification, the ecologically purified effluent was obtained.

[0075] The purified effluent was introduced into an aeration tank, which was 4m deep. The tank contained evenly distributed biological packing columns at a density of 6000 columns / acre, and evenly distributed microporous aerators at a density of 220 aerators / acre at the bottom. The distance between the top of the aerators and the bottom of the biological packing columns was 1m. The biological packing columns were ring-shaped, 2m high, with an inner diameter of 5cm and an outer diameter of 8cm. The ring-shaped structure was filled with a mixture of biochar, volcanic rock, and ceramsite in a mass ratio of 1:1:1. Spirulina was attached to the packing material, with a spirulina-to-packing material mass ratio of 0.5:1. After 3 hours of aeration, the tank was disinfected with sodium hypochlorite for 60 minutes.

[0076] Test Example 1

[0077] The effluent treated by the methods of Examples 1 to 4 and Comparative Examples 1 to 6 were used as samples, and their nitrogen and phosphorus removal rates were tested. The results are shown in Table 1.

[0078] Table 1. Nitrogen and Phosphorus Removal Efficiency

[0079]

[0080] As shown in Table 1, compared with Comparative Examples 1 to 6, Examples 1 to 4 have higher nitrogen and phosphorus removal rates, indicating that Bacillus subtilis, Bacillus licheniformis, and Micrococcus luteus have a certain synergistic effect. In this invention, after mixing Spirulina with Bacillus subtilis, Bacillus licheniformis, and Micrococcus luteus, an algae-bacteria symbiotic system is formed, which further improves the nitrogen and phosphorus removal efficiency in aquaculture wastewater.

[0081] Test Example 2

[0082] The effluent treated by the methods of Examples 1 to 4 and Comparative Examples 1 to 6 were used as samples, and their COD removal rate and turbidity removal rate were tested. The results are shown in Table 2.

[0083] Table 2. Wastewater Treatment Effect

[0084]

[0085] As shown in Table 2, compared with Comparative Examples 1 to 6, Examples 1 to 4 have higher COD removal rates and turbidity removal rates. This indicates that the present invention can effectively improve purification efficiency by introducing aquatic plants and animals into the ecological purification pond and coordinating their proportions.

[0086] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for treating wastewater from factory-scale aquaculture, characterized in that, The method comprises the following steps: introducing the aquaculture tail water into a sedimentation tank for sedimentation to obtain the sedimented tail water, wherein the sedimentation tank contains water retaining facilities, and the sedimentation time is 1-3 hours; introducing the sedimented tail water into an ecological purification tank for purification for 2-4 hours to obtain the ecologically purified tail water; planting submerged plants, floating leaf plants and emergent plants in the ecological purification tank, and breeding silver carp, catfish, crucian carp, freshwater shrimps, snails and river mussels; the amount of silver carp to be bred is 50-100 tail / mu, the amount of catfish to be bred is 30-50 tail / mu, the amount of crucian carp to be bred is 100-200 tail / mu, the amount of freshwater shrimps to be bred is 10-20 kg / mu, the amount of snails to be bred is 150-300 kg / mu, and the amount of river mussels to be bred is 40-50 kg / mu; introducing the ecologically purified tail water into an aeration tank for aeration for 2-5 hours, and then performing disinfection treatment; the aeration tank is provided with uniformly distributed biological filler columns and uniformly distributed microporous aeration heads at the bottom of the tank; the density of the biological filler columns is 5000-8000 columns / mu, and the density of the microporous aeration heads is 220-250 / mu; the biological filler columns are composed of fillers and microorganisms; the fillers are one or more of biological charcoal, volcanic stones and ceramic granules; the microorganisms are spirulina, bacillus subtilis, bacillus licheniformis and micrococcus luteus; the mass ratio of spirulina to fillers is 0.2-2:1; the mass ratio of bacillus subtilis, bacillus licheniformis and micrococcus luteus is 2-5:1-3:1-2; and the mass ratio of the total mass of bacillus subtilis, bacillus licheniformis and micrococcus luteus to the fillers is 0.01-0.02:

1.

2. The method of claim 1, wherein, The volume ratio of the sedimentation tank, the ecological purification tank and the aeration tank is 200-300:350-450:900-1200; the depth of the sedimentation tank is 2.5-3.5 m, the depth of the ecological purification tank is 1.5-2.5 m, and the depth of the aeration tank is 3-5 m.

3. The method of claim 1, wherein, The submerged plants include Vallisneria and Hydrilla verticillata; the floating leaf plants include Nymphaea; and the emergent plants include Phragmites australis and Typha.

4. The method of claim 1, wherein, The planting area of the submerged plants accounts for 20% of the ecological purification tank, the planting area of the floating leaf plants accounts for 20% of the ecological purification tank, and the planting area of the emergent plants accounts for 20% of the ecological purification tank.

5. The method of claim 1, wherein, The distance between the top of the aeration head and the bottom of the biological filler column is 1 m.

6. The method of claim 1, wherein, The biological filler column has a ring structure, a height of 1.5-2.5 m, an inner cross-sectional diameter of 5-8 cm, an outer cross-sectional diameter of 7-10 cm, and an outer diameter greater than the inner diameter.

7. The method of claim 1, wherein, The specific surface area of the biofiller column is 2.5 mm 2 / g ~ 4 mm 2 / g.

8. The method of claim 1, wherein, The disinfection treatment time is 30-60 minutes.

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