Culture tail water denitrification device adapting to low temperature and treatment method

Abstract

The invention discloses an aquaculture tail water denitrification device adapting to low temperature and a treatment method, and relates to the technical field of aquaculture tail water treatment. According to the invention, the strain Acinetobacter sp. LF10 with relatively strong temperature adaptability is combined with the ecological base filler, and the strain Acinetobacter sp. LF10 and the ecological base filler are taken as a main body to construct an aquaculture tail water denitrification device adapting to low temperature, so that a new scheme is provided for low-temperature treatment of the aquaculture tail water. The method has a good effect of removing nitrogen in the aquaculture tail water at low temperature, can effectively remove COD and TP, has the advantages of high stability, convenience in management and the like, provides a new solution for solving the difficulty in low-temperature treatment of the aquaculture tail water, and has a great application value in the aspect of low-temperature aquaculture tail water treatment.

Description

Technical Field

[0001] The invention relates to the technical field of aquaculture tail water treatment, and in particular to an aquaculture tail water denitrification device and a treatment method adapted to low temperatures. Background Art

[0002] Aquaculture is an important fishery production entity and an important source of high-quality protein. The annual wastewater discharge from aquaculture is very large, which leads to serious environmental and disease problems. Nitrogen pollution in water bodies not only endangers aquatic organisms and affects the ecological balance, but also poses a serious threat to human health. Therefore, denitrification of aquaculture tailwater has become one of the current work focuses.

[0003] In denitrification treatment, biological denitrification process is the most widely used. With the development of biological denitrification technology, more and more new denitrification microorganisms have been isolated, mainly aerobic denitrifying bacteria and heterotrophic nitrifying aerobic denitrifying bacteria. Compared with traditional nitrifying bacteria and denitrifying bacteria, they have shown stronger competitiveness in the field of wastewater denitrification. However, the new biological denitrification is still mainly in the stage of small-scale laboratory tests in basic research and application. In practical applications, there are problems such as poor strain effectiveness, colonization ability and competitiveness, and unstable effects. The new denitrification bacteria are also added to the reactor in the form of multi-microbial agents to improve the denitrification efficiency of the reactor.

[0004] Biofilm treatment system is a promising wastewater treatment technology that can better remove organic matter and nutrients. Different factors such as carrier type, filling ratio, reactor configuration, microorganism type, biofilm thickness, adhered and suspended biomass, aeration degree, environmental factors, etc. have an important impact on the performance of biofilm treatment system. Among these factors, the carrier is a key component of the biofilm treatment system process and has a great impact on its performance. The carrier provides shelter for the development of microorganisms through the adhesion mechanism of the biofilm, forming a stable and active microbial community. In the biofilm treatment system, different carriers are used to support microbial activity. The properties of the carrier, including surface roughness, hydrophilicity, durability, density and material type, will affect the adhesion of microorganisms and thus affect the treatment efficiency. Temperature is one of the decisive factors for whether microorganisms can carry out normal growth and metabolism. Too high and too low temperatures will affect the growth and metabolism of microorganisms by affecting enzyme activity and gene expression. Biological denitrification is sensitive to ambient temperature, and the denitrification efficiency is greatly affected by temperature.

[0005] In recent years, more and more extreme temperature tolerant denitrifying bacteria have been isolated, such as Daegu Chelating Coccus TAD1 and Anaerobic Bacillus HA, which can maintain efficient denitrification at 50°C, as well as some low-temperature resistant Acinetobacter, Pseudomonas, and Pseudomonas tolas. However, in practical applications, how to keep biological denitrification stable and efficient at extreme temperatures is still a huge problem. Summary of the invention

[0006] The purpose of the present invention is to provide a low temperature-adaptable aquaculture tail water denitrification device and treatment method to solve the problems existing in the above-mentioned prior art.

[0007] To achieve the above object, the present invention provides the following solutions:

[0008] The present invention provides a denitrification device for aquaculture tail water, comprising: a biological filter, an ecological base filler loaded with denitrification bacteria, and an aeration unit;

[0009] The ecological-based filler loaded with denitrifying bacteria is filled in the biofilter, and the aeration unit is used to aerate the ecological-based filler loaded with denitrifying bacteria;

[0010] The components of the ecological-based filler include cotton and polyethylene; the denitrifying bacteria is Acinetobacter sp. LF10, which is currently preserved in the Guangdong Provincial Microbiological Culture Collection Center with a preservation number of GDMCC NO: 64288.

[0011] Furthermore, the aquaculture tailwater denitrification device comprises: a biological filter, an ecological base filler loaded with denitrifying bacteria, an aeration unit, an aquaculture tailwater storage tank, a carbon source storage tank, an inlet mixing tank and a reactor outlet storage tank;

[0012] The biofilter is provided with a water outlet at the top and a water inlet at the bottom;

[0013] The water inlet is connected to the outlet of the water inlet mixing tank; the carbon source storage tank and the aquaculture tail water storage tank are connected to the inlet of the water inlet mixing tank in parallel; the water outlet is connected to the reactor outlet water storage tank;

[0014] The ecological-based filler loaded with denitrifying bacteria is filled in the biofilter, and the aeration unit is used to aerate the ecological-based filler loaded with denitrifying bacteria;

[0015] The bottom of the biofilter is filled with quartz sand; the ecological-based filler loaded with denitrifying bacteria is filled above the quartz sand;

[0016] The components of the ecological-based filler include cotton and polyethylene; the denitrifying bacteria is Acinetobacter sp. LF10, and its preservation number is GDMCC NO: 64288.

[0017] Furthermore, the preparation method of the eco-based filler loaded with denitrifying bacteria (incubated eco-based carrier filler) comprises the following steps:

[0018] The ecological base filler is placed in the denitrification bacteria concentration of 10 8CFU / mL of bacterial solution was incubated at 30 ± 1.5℃ in a constant temperature oscillator for 10-15 days. During the incubation period, 1.0±0.5 g NH4Cl, 1.0±0.5 g KNO3 and 2.0±1.0 g sodium acetate were added to each liter of bacterial solution every 1-2 days; the rotation speed was controlled at 180 rpm during the incubation process.

[0019] Furthermore, the concentration of the denitrifying bacteria solution is 10 8 CFU / mL.

[0020] Furthermore, the aeration unit includes an air pump and an aeration tank.

[0021] Furthermore, the water inlet and the water outlet are provided with valve switches.

[0022] Furthermore, a constant temperature peristaltic pump is arranged between the inlet mixing tank and the biological filter tank; a constant temperature peristaltic pump is arranged between the carbon source storage tank and the inlet mixing tank, and a constant temperature peristaltic pump is arranged between the aquaculture tail water storage tank and the inlet mixing tank.

[0023] Improving the operating effect of biological denitrification process at low temperature is a technical pursuit in this field. The present invention combines the strain Acinetobacter sp. LF10 with strong temperature adaptability with ecological base filler, and uses it as the main body to construct an aquaculture tailwater denitrification device that adapts to low temperature, providing a new solution for low-temperature treatment of aquaculture tailwater. The device of the present invention has a good low-temperature denitrification effect, and can quickly remove ammonia nitrogen, nitrate nitrogen and nitrite nitrogen in aquaculture tailwater under low temperature conditions. The device also has the advantages of strong stability, simple structure, convenient management, and small footprint.

[0024] The present invention also provides the use of the above-mentioned aquaculture tail water denitrification device in low temperature treatment of aquaculture tail water; the low temperature is 15±0.5°C.

[0025] The present invention further provides a method for treating aquaculture tail water at low temperature, comprising the following steps: passing the aquaculture tail water into a biofilter containing ecological base fillers, and treating the aquaculture tail water at 15±0.5°C; the dissolved oxygen concentration in the treatment process is 7.50±1.0 mg / L, and the hydraulic retention time is 12h; the denitrifying bacteria is Acinetobacter sp. LF10, and the preservation number is GDMCC NO: 64288; sodium acetate is used as a carbon source in the treatment process, and the C / N is controlled to be 6-10.

[0026] Furthermore, the treatment is carried out by adopting a method in which water enters the bottom of the biological filter and overflows from the top.

[0027] Furthermore, the pH of the aquaculture tail water is 7.5±0.5.

[0028] The present invention discloses the following technical effects:

[0029] The present invention has a good nitrogen removal effect on aquaculture tail water at low temperature, and can also effectively remove COD and TP, and has the advantages of strong stability and convenient management. It provides a new solution to the difficulty of low-temperature treatment of aquaculture tail water, and has great application value in low-temperature aquaculture tail water treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0031] Figure 1 This is a schematic diagram of the structure of the aquaculture tail water denitrification device used in Example 1 of the present invention;

[0032] Figure 2 This is a physical picture of the eco-based filler used in Example 1 of the present invention;

[0033] Figure 3 These are scanning electron microscope observation images of the eco-based carrier filler in Example 2 of the present invention at different magnifications. DETAILED DESCRIPTION

[0034] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0035] It should be understood that the terms described in the present invention are only for describing a particular embodiment and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. The intermediate value in any stated value or stated range, and each smaller range between any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0036] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0037] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present invention description and examples are exemplary only.

[0038] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0039] The eco-based fillers used in the examples of the present invention were purchased from Ningbo Kaifu Environmental Protection Co., Ltd. (see Figure 2 ), composed of cotton and polyethylene, and other materials with similar compositions can be used as the eco-based filler of the present invention.

[0040] Figure 1 The structure diagram of the aquaculture tail water denitrification device used in Example 1 of the present invention is shown in the figure. 1. Biofilter outlet; 2. Biofilter inlet; 3. Valve switch; 4. Constant flow peristaltic pump; 5. Quartz sand; 6. Aeration stone; 7. Incubated ecological base carrier filler; 8. Air pump; 9. Reactor outlet storage tank; 10. Aquaculture tail water storage tank; 11. Carbon source storage tank; 12. Inlet mixing tank; 13. Biofilter body.

[0041] The aquaculture tail water denitrification device used in Example 1 of the present invention: the main cylindrical biofilter has a diameter of 10.0 cm and a height of 55.0 cm. The water inlet of the biofilter is located 5.0 cm above the bottom, and the water outlet is located 5.0 cm below the top. The bottom of the biofilter is laid with quartz sand with a height of 10.0 cm. The filling amount of the ecological base filler loaded with denitrifying bacteria is 12.8% of the volume of the biofilter.

[0042] The denitrifying bacteria Acinetobacter sp. LF10 used in the embodiment of the present invention is deposited in the Guangdong Microbial Culture Collection Center, with the deposit address: 5th Floor, Building 59, No. 100 Xianlie Middle Road, Guangzhou, the deposit time: January 17, 2024, and the deposit number: GDMCC NO: 64288.

[0043] The eco-based filler loaded with denitrifying bacteria is prepared by the following method:

[0044] The eco-based filler was placed at a concentration of 10 8 CFU / mL in 100 mL Acinetobacter sp. LF10 bacterial solution and incubate in a constant temperature oscillator for 10 days (30°C, 180 rpm), adding 0.5 g NH4Cl, 0.5 g KNO3, and 1.0 g sodium acetate to the bacterial solution every 2 days.

[0045] Example 1

[0046] The tailwater denitrification device was used to treat the tailwater of largemouth bass at 15°C. The stocking density of largemouth bass was 12.5 kg / m 3 The daily feeding amount during the breeding period is 1.5% of the body weight of the cultured largemouth bass.

[0047] The aquaculture tail water is placed in an aquaculture tail water storage tank 10, and a 10.0 g / L sodium acetate solution is stored in a carbon source storage tank 11. The sodium acetate solution and the aquaculture tail water are mixed in an inlet mixing tank 12 at a volume ratio of 1:99 by a constant flow peristaltic pump 4. The valve switch 3 is opened, and the mixed aquaculture tail water is passed into the biofilter body 13 through the biofilter inlet 2 by the constant flow peristaltic pump 4. The sodium acetate concentration of the inlet water of the biofilter body 13 is maintained at 0.1 g / L, and the C / N is controlled to be 6.4±0.7. The aquaculture tail water is treated with quartz sand 5 and then treated with an incubated eco-based carrier filler 7, and finally enters the reactor outlet water storage tank 9 through the biofilter outlet 1.

[0048] The device was operated continuously for 60 days. During the operation, the air pump 8 and the aeration stone 6 were used to maintain the dissolved oxygen concentration in the biological filter body 13 at 7.50±0.64 mg / L, the pH of the aquaculture tail water at 7.4±0.3, and the hydraulic retention time at 12 h.

[0049] The inlet and outlet water samples of the biofilter were collected every two days to test the NH4 + -N、NO3 — -N, NO2 — -N, TN and COD concentrations are used to analyze the low-temperature denitrification effect of the device. TN is measured by alkaline potassium persulfate digestion UV spectrophotometry; NO3 is measured by thymol spectrophotometry - -N; N-(1-naphthyl)-ethylenediamine spectrophotometric determination of NO2 - -N; Salicylic acid spectrophotometric measurement of NH4 + -N; COD was determined by dichromate method.

[0050] The results showed that the average influent NH4 +-N, NO3 — -N, NO2 — -N and TN concentrations were 7.35, 17.47, 2.26 and 27.35 mg / L, respectively, and the average effluent NH4 + -N, NO3 — -N, NO2 — -N and TN concentrations were 1.40, 2.18, 0.32 and 4.18 mg / L, respectively. + -N, NO3 — -N, NO2 — The average removal rates of -N and TN were as high as 80.96%, 87.50%, 85.99% and 84.73%. The average influent COD concentration of the biofilter for 60 days was 151.94 mg / L, and the average removal rate was 89.17%. The effluent COD concentration of the biofilter remained at a low level, with an average effluent concentration of 16.46 mg / L.

[0051] The device of the present invention can also remove part of TP in aquaculture tail water. The average influent TP concentration of the biofilter for 60 days is 3.12 mg / L, the average effluent concentration is 2.11 mg / L, and the removal rate is 32.39%.

[0052] The above results show that the device of the present invention has a good low-temperature denitrification effect and can quickly remove NH4 in aquaculture tail water under low temperature conditions. + -N, NO3 — -N, NO2 — -N, and during the operation of the device, the COD of the biofilter effluent is stably maintained at a low level, which will not cause secondary pollution. In addition, the device also has a good TP removal effect in aquaculture tail water.

[0053] Example 2

[0054] At the end of the 60-day treatment period of Example 1, the carrier filler was collected, and the biofilm sample was rinsed with 0.1 mol / L phosphate buffer (pH 7.4) for 5 min, and then fixed in glutaraldehyde (2.5%) for 12 h; rinsed again with phosphate buffer twice, each for 10 minutes; and then dehydrated in ethanol solutions with concentrations of 30%, 50%, 70%, 80%, 90%, 95% and 100% in sequence. Finally, the sample was immersed in 50%, 70%, 80%, 90%, 95% and 100% isoamyl acetate solutions for 15 min in sequence. After freeze drying and coating, it was observed using a scanning electron microscope, and the results are as follows Figure 3After the device was operated at low temperature for 60 days, a large number of reticular structures were formed on the surface of the eco-based carrier, and a variety of filaments and rod-shaped bacteria grew thickly on the surface of the carrier, which shows that the eco-based carrier used in the device of the present invention is easy for microorganisms to attach. The well-grown biofilm on the surface of the carrier and the stable nitrogen removal effect of the biofilter within 60 days both reflect that the device of the present invention has good operating stability.

[0055] In summary, the device of the present invention has a good denitrification effect for low-temperature aquaculture tail water, can quickly remove ammonia nitrogen, nitrate nitrogen and nitrite nitrogen in the water body at 15°C, and the effluent COD is stably maintained at a low level, will not cause secondary pollution, and has a good TP removal effect. In addition, the device of the present invention also has the advantages of simple structure, easy operation, small footprint, low operating cost, strong stability, etc., which can provide guarantee for maintaining good water quality for aquaculture water bodies, and has great application value in low-temperature tail water treatment.

[0056] The present invention can quickly remove ammonia nitrogen, nitrate nitrogen and nitrite nitrogen in aquaculture tail water under low temperature conditions, and has great application value in low-temperature aquaculture tail water treatment; the device of the present invention has good stability, can operate for a long time and maintain a good denitrification effect, the device has a simple structure, is easy to manage, occupies a small area and has the characteristics of low cost, and has broad application prospects.

[0057] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A denitrification device for aquaculture tail water, characterized in that: include: Biofilters, eco-based fillers loaded with denitrifying bacteria, and aeration units; The ecological-based filler loaded with denitrifying bacteria is filled in the biofilter, and the aeration unit is used to aerate the ecological-based filler loaded with denitrifying bacteria; The components of the ecological-based filler include cotton and polyethylene; the denitrifying bacteria is Acinetobacter sp. LF10, and its preservation number is GDMCC NO: 64288.

2. The aquaculture tail water denitrification device according to claim 1, characterized in that: It also includes: aquaculture tailwater storage tank, carbon source storage tank, inlet mixing tank and reactor outlet water storage tank; The biofilter is provided with a water outlet at the top and a water inlet at the bottom; The water inlet is connected to the outlet of the water inlet mixing tank; the carbon source storage tank and the aquaculture tail water storage tank are connected to the inlet of the water inlet mixing tank in parallel; the water outlet is connected to the reactor outlet water storage tank; The bottom of the biological filter is filled with quartz sand; the ecological base filler loaded with denitrification bacteria is filled above the quartz sand.

3. The aquaculture tail water denitrification device according to claim 1, characterized in that: The method for preparing the eco-based filler loaded with denitrifying bacteria comprises the following steps: The eco-based filler is placed in the bacterial solution of the denitrifying bacteria and incubated at 30±1.5°C.

4. The aquaculture tail water denitrification device according to claim 1, characterized in that: The aeration unit comprises an air pump and an aeration tank.

5. The aquaculture tail water denitrification device according to claim 2, characterized in that: The water inlet and the water outlet are provided with valve switches.

6. The aquaculture tail water denitrification device according to claim 2, characterized in that: A constant temperature peristaltic pump is arranged between the influent mixing tank and the biological filter tank; a constant temperature peristaltic pump is arranged between the carbon source storage tank and the influent mixing tank; and a constant temperature peristaltic pump is arranged between the aquaculture tail water storage tank and the influent mixing tank.

7. Application of the aquaculture tail water denitrification device according to any one of claims 1 to 6 in low temperature treatment of aquaculture tail water, characterized in that: The low temperature is 15 ± 0.5°C.

8. A method for treating aquaculture tail water at low temperature, characterized in that: The method comprises the following steps: passing aquaculture tail water into a biofilter tank to which an eco-based filler loaded with denitrifying bacteria is added, and treating the aquaculture tail water at 15±0.5°C; the dissolved oxygen concentration during the treatment process is 7.50±1.0 mg / L, and the hydraulic retention time is 12h; the denitrifying bacteria is Acinetobacter sp.LF10, and the deposit number is GDMCC NO: 64288; During the treatment process, sodium acetate was used as the carbon source and the C / N ratio was controlled at 6-10.

9. The method according to claim 8, characterized in that The treatment is carried out by using the method of water entering from the bottom of the biofilter and overflowing from the top.

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