Cultivation tail water treatment method

Abstract

The invention relates to a culture tail water treatment method, and belongs to the technical field of wastewater treatment. The method comprises the following steps: S1, pretreating aquaculture tail water to obtain primary purified water; s2, inputting the primary purified water obtained in the step S1 into a combined biochemical pool for biochemical treatment to obtain secondary purified water; and S3, performing disinfection treatment on the secondary purified water obtained in the step S2 to obtain the aquaculture water. The aquaculture treatment method provided by the invention can effectively remove pollutants such as ammonia nitrogen, nitrite, phosphorus, organic matters and the like in the aquaculture tail water, so that the treated aquaculture tail water meets the class I water quality standard or class II water quality standard, can be directly used for aquaculture, and is beneficial to realizing cyclic utilization of aquaculture water.

Description

Technical Field

[0001] The invention relates to the technical field of wastewater treatment, and in particular to a method for treating aquaculture tail water. Background Art

[0002] Aquaculture tailwater generally refers to wastewater discharged into the external environment during aquaculture production. Aquaculture tailwater contains pollutants such as ammonia nitrogen, nitrite, phosphorus, organic matter, and harmful microorganisms. During the aquaculture process, if the aquaculture tailwater is not treated in a timely and effective manner and discharged into natural waters without treatment, it will pollute the aquatic environment and the adjacent soil.

[0003] With the development of aquaculture, the development of aquaculture tailwater treatment technology has received more and more attention. At present, the most commonly used aquaculture tailwater treatment method is aquatic plant purification, but this method has low treatment efficiency and needs to increase the planting area of ​​aquatic plants to improve the aquaculture tailwater treatment effect, which can no longer meet the needs of industrial development. Therefore, it is very necessary to develop an efficient aquaculture tailwater treatment method. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a method for treating aquaculture tail water.

[0005] To achieve the above object, the technical solution adopted by the present invention is:

[0006] A method for treating aquaculture tail water comprises the following steps:

[0007] S1, pre-treating the aquaculture tail water to obtain primary purified water;

[0008] S2, inputting the primary purified water obtained in step S1 into the combined biochemical pool for biochemical treatment to obtain secondary purified water;

[0009] S3. Disinfect and disinfect the secondary purified water obtained in step S2 to obtain aquaculture water.

[0010] The combined biochemical pool in step S2 includes a fixed bed pool and four fluidized bed pools connected in sequence; the fluidized bed pool is provided with a water inlet and a water outlet, and the water inlet is located below the water outlet; the fixed bed pool is provided with an input port and a discharge port, and the input port is located below the discharge port; in the four fluidized bed pools connected in sequence, the water outlet of the previous fluidized bed pool is connected with the water inlet of the next fluidized bed pool through a water passage, and the water outlet of the fluidized bed pool at the tail end is connected with the input port of the fixed bed pool through a water passage.

[0011] As a preferred embodiment of the aquaculture tail water treatment method of the present invention, two grid plates are horizontally arranged in the fluidized bed pool, the two grid plates are located between the water outlet and the water inlet, and filler is arranged between the two grid plates, and the filling rate of the filler in the fluidized bed pool is 40-60%.

[0012] As a preferred embodiment of the aquaculture tail water treatment method of the present invention, biological ropes are vertically arranged in the fixed bed pool, the porosity of the biological ropes is 70-90%, the number of the biological ropes is 300-500, the distance between any two adjacent biological ropes is 5-15 cm, the diameter of the biological ropes is 70-90 mm, and the length is 3-4 m.

[0013] As a preferred embodiment of the aquaculture tail water treatment method of the present invention, when the biochemical treatment is performed in step S2, the water inlet flow rate of the combined biochemical pool is 500-1000m 3 / min, the hydraulic retention time of the combined biochemical pool is 10 to 20 minutes, and the aeration volume in the fluidized bed pool is 16 to 24 m 3 / min, the aeration rate in the fixed bed pool is 6 to 12m 3 / min.

[0014] As a preferred embodiment of the aquaculture tail water treatment method of the present invention, in step S3, the disinfection treatment condition is: the ultraviolet irradiation intensity is not less than 125mW·s / cm 2 , water inlet flow rate is 100~300m 3 / h, hydraulic retention time is 5 to 7s.

[0015] As a preferred embodiment of the aquaculture tail water treatment method of the present invention, the aquaculture tail water includes bottom drainage and side drainage of the aquaculture pond, and step S1 includes:

[0016] The bottom drainage of the culture pond is input into the vertical flow sedimentation tank for sedimentation treatment to separate the sediment and the vertical flow effluent;

[0017] The drainage from the aquaculture pond is input into a microfiltration machine for filtration treatment to obtain microfiltration effluent and intercepted matter;

[0018] The obtained intercepted material and vertical effluent are respectively input into a filter press for filter pressing treatment to obtain residue and filter press effluent;

[0019] The obtained effluent from the filter press is input into a biochemical pool of a moving bed biofilm reactor for biochemical treatment, and the effluent from the biochemical pool of the moving bed biofilm reactor is input into a denitrification tank for denitrification treatment;

[0020] If the aquaculture density in the breeding pond is less than 15kg / m 3, the effluent from the denitrification tank and the effluent from the microfiltration are combined and the temperature is adjusted to obtain primary purified water;

[0021] If the aquaculture density of the breeding pond is ≥15kg / m 3 The obtained microfiltration effluent is subjected to protein separation treatment, and the effluent from the denitrification tank is temperature-adjusted and combined with the microfiltration effluent after protein separation to obtain primary purified water.

[0022] Furthermore, the water flow rate of the vertical flow sedimentation tank is 300-500m 3 / h. In the sedimentation process, controlling the water flow rate of the vertical flow sedimentation tank within the above range can cause the residual bait, feces and other particles with a particle size larger than 3mm in the aquaculture tail water to settle and separate because their own gravity is greater than the supporting effect of the rising water flow.

[0023] Furthermore, the filter mesh number of the microfilter is 100 to 300 meshes.

[0024] Furthermore, in step S1, the water inlet flow rate of the biochemical pool of the moving bed biofilm reactor is 1.8 to 3.6 m 3 / h, temperature is 18~32℃, hydraulic retention time is 12~24h, aeration volume is 15~20m 3 / min.

[0025] Furthermore, in step S1, the water inlet flow rate of the denitrification tank is 1.6-3.5m 3 / h, the temperature is 18-32℃, and the hydraulic retention time is 16-24h.

[0026] Furthermore, step S1 further includes:

[0027] The excess sludge in the biochemical pool of the moving bed biofilm reactor is discharged, and the residue and the discharged active sludge are transferred to an ex situ fermentation bed for natural fermentation to obtain solid organic fertilizer.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] The aquaculture treatment method provided by the present invention can effectively remove pollutants such as ammonia nitrogen, nitrite, phosphorus, heavy metals and organic matter in aquaculture tail water, so that the treated aquaculture tail water meets Class I water quality standards or Class II water quality standards, can be directly used for aquaculture, and is conducive to the recycling of aquaculture water bodies. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 A flow chart of aquaculture tail water treatment provided by the present invention;

[0031] Figure 2 This is a schematic structural diagram of the combined biochemical pool provided by the present invention.

[0032] In the figure, 1-fluidized bed, 11-water inlet, 12-water outlet, 13-grid plate, 14-filler, 2-fixed bed, 21-input port, 22-discharge port, 23-biological rope, 3-water passage, 4-aeration device. DETAILED DESCRIPTION

[0033] In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0034] Example 1

[0035] The embodiment of the method for treating aquaculture tail water of the present invention is as follows: Figure 1 As shown, the aquaculture tail water treatment method comprises the following steps:

[0036] (1) The drainage from the bottom of the aquaculture pond is input into a vertical flow sedimentation tank for sedimentation treatment to separate the sediment and the vertical flow effluent; the water inlet flow rate of the vertical flow sedimentation tank is 400m 3 / h;

[0037] The bottom drainage and side drainage of the culture pond are input into a microfiltration machine for filtration treatment to obtain microfiltration effluent and intercepted material; the mesh number of the microfiltration machine is 200 meshes;

[0038] (2) The obtained intercepted material and the vertical effluent are transferred to a filter press through a pipeline for filtration treatment to obtain residue and filtration effluent; the filtration effluent is input into a moving bed biofilm reactor biochemical pool for biochemical treatment; during the biochemical treatment process, the water inlet flow rate of the moving bed biofilm reactor biochemical pool (i.e., MBBR pool) is 2.7 m 3 / h, temperature is 28℃, hydraulic retention time is 15h, aeration volume is 15m 3 / min, to discharge the excess sludge from the biochemical pool of the moving bed biofilm reactor;

[0039] The effluent from the MBBR pool is fed into a denitrification tank for denitrification treatment. The water inlet flow rate of the denitrification tank is 2.5 m 3 / h, temperature is 28℃, hydraulic retention time is 12h;

[0040] (3) If the aquaculture density in the breeding pond is less than 15 kg / m 3 , the effluent from the denitrification tank and the effluent from the microfiltration are respectively input into the regulating tank for merging, and the water temperature is adjusted to 28°C using a water source heat pump temperature control device to obtain primary purified water;

[0041] (4) inputting the obtained primary purified water into a combined biochemical pool for biochemical treatment to obtain secondary purified water;

[0042] If the aquaculture density of the breeding pond is ≥15kg / m 3 The microfiltration water is input into the protein skimmer for treatment. During the treatment, air is introduced to remove suspended impurities in the water. The water outlet from the denitrification tank is temperature-adjusted and then combined with the water outlet from the protein skimmer to obtain primary purified water.

[0043] like Figure 2 As shown, in this embodiment, the combined biochemical pool includes a fixed bed pool 2 and four fluidized bed pools 1 connected in sequence; the fluidized bed pool 1 is provided with a water inlet 11 and a water outlet 12, and the water inlet 11 is located below the water outlet 12; the fixed bed pool 2 is provided with an input port 21 and a discharge port 22, and the input port 21 is located below the discharge port 22; in the four fluidized bed pools 1 connected in sequence, the water outlet 11 of the upper fluidized bed pool 1 is connected with the water inlet 12 of the next fluidized bed pool 1 through a water passage 3, and the water outlet 12 of the fluidized bed pool 1 at the tail end is connected with the input port 12 of the fixed bed pool 2 through a water passage 3; two grid plates 13 are horizontally arranged in the fluidized bed pool 1 , two grid plates 13 are located between the water outlet 12 and the water inlet 11, and a filler 14 is arranged between the two grid plates 13, and the filling rate of the filler 14 in the fluidized bed pool 1 is 50%; a biological rope 23 is vertically arranged in the fixed bed pool 2, and the biological rope 23 is made of polypropylene fiber. The porosity of the biological rope 23 is 80%, and the number of the biological ropes 23 is 430. The two ends of the biological rope 23 are respectively connected to a fixing rod 24, and the fixing rod 24 is fixed in the fixed bed pool 2 through a cross bar 25. The 430 biological ropes 23 are evenly spaced in the fixed bed 2, and the distance between any two adjacent biological ropes 23 is 10 cm. The diameter of the biological rope 23 is 80 mm and the length is 3.8 m;

[0044] When the biochemical treatment is carried out in step (4), the water inlet flow rate of the combined biochemical pool is 800m 3 / min, the hydraulic retention time of the combined biochemical pool is 15min, and the aeration volume in the fluidized bed pool 2 is 20m 3 / min, the aeration volume in the fixed bed pool 3 is 10m 3 / min.

[0045] (5) The obtained secondary purified water is input into the UV pool and the AOT photocatalytic oxidation equipment is used at an ultraviolet radiation intensity of 125 mW·s / cm 2 The disinfection treatment was carried out under the conditions of, and the water flow rate of the ultraviolet pool was 200m 3 / h, hydraulic retention time is 5-7s, and aquaculture water is obtained.

[0046] Example 2

[0047] The difference between this embodiment and embodiment 1 is that in step (2) of this embodiment, the water inflow rate of the MBBR pool is 2.4m3 / h, temperature is 28℃, hydraulic retention time is 12h, aeration volume is 16m 3 / min.

[0048] Example 3

[0049] The difference between this embodiment and embodiment 1 is that in step (2) of this embodiment, the water inlet flow rate of the MBBR pool is 3.6m 3 / h, temperature is 28℃, hydraulic retention time is 10h, aeration volume is 18m 3 / min.

[0050] Example 4

[0051] The difference between this embodiment and embodiment 1 is that in step (2) of this embodiment, the water inlet flow rate of the MBBR pool is 1.8m 3 / h, temperature is 28℃, hydraulic retention time is 10h, aeration volume is 15m 3 / min.

[0052] Example 5

[0053] The difference between this embodiment and embodiment 1 is that in step (5) of this embodiment, the water inlet flow rate of the combined biochemical pool is 750m 3 / min, the hydraulic retention time of the combined biochemical pool is 12min, and the aeration volume in the fluidized bed pool 2 is 18m 3 / min, the aeration volume in the fixed bed pool 3 is 8m 3 / min.

[0054] Example 6

[0055] The difference between this embodiment and embodiment 1 is that in step (5) of this embodiment, the water inlet flow rate of the combined biochemical pool is 500m 3 / min, the hydraulic retention time of the combined biochemical pool is 10min, and the aeration volume in the fluidized bed pool 2 is 16m 3 / min, the aeration volume in the fixed bed pool 3 is 6m 3 / min.

[0056] Example 7

[0057] The difference between this embodiment and embodiment 1 is that in step (5) of this embodiment, the water inlet flow rate of the combined biochemical pool is 1000m 3 / min, the hydraulic retention time of the combined biochemical pool is 20min, and the aeration volume in the fluidized bed pool 2 is 24m 3 / min, the aeration volume in the fixed bed pool 3 is 12m 3 / min.

[0058] Comparative Example 1

[0059] The difference between this comparative example and Example 1 is that in this comparative example, no biological rope is provided in the fixed bed pool of the combined biochemical pool.

[0060] In order to verify the treatment effect of the methods provided in the above embodiments and comparative examples on aquaculture tail water, the present invention adopts the methods provided in the above embodiments and comparative examples to treat the bottom drainage and side drainage of the aquaculture pond of the same aquaculture system, and the flow rate of the bottom drainage is 3 times the flow rate of the side drainage. The aquaculture pond is cultured with pearl gentian grouper, and the aquaculture density is 12kg / m 3 During the treatment process, the ammonia nitrogen concentration and nitrite concentration in the side drainage were regularly tested, and the ammonia nitrogen concentration and nitrite concentration of the aquaculture water were obtained. The test statistical results are shown in Table 1.

[0061] Table 1

[0062]

[0063] Effect Example 1

[0064] In the same breeding site, two breeding ponds of the same specifications were selected and the same species of pearl grouper were stocked at the same stocking density. During the breeding process of pearl grouper, bottom drainage and side drainage were carried out regularly, and the water quality of the side drainage was tested, and the breeding water with the same volume as the drainage was supplemented.

[0065] Experimental group: The drainage from the culture pond A was treated by the method of Example 1 and then returned to the culture pond A; the treated source water was transported to the culture pond.

[0066] Control group: The treated source water was transported to culture pond B.

[0067] The treated source water in the experimental group A and the experimental group B is: the water obtained after the source water is subjected to electrolytic disinfection treatment, water temperature adjustment, combined biochemical pool biochemical treatment and disinfection treatment.

[0068] The amount of source water used by each group after 60 days of culture was counted.

[0069] Statistical results show that the quality of the source water used in the experimental group is 1 / 30 of that in the control group.

[0070] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A method for treating aquaculture tail water, characterized in that: The steps include: S1, pre-treating the aquaculture tail water to obtain primary purified water; S2, inputting the primary purified water obtained in step S1 into the combined biochemical pool for biochemical treatment to obtain secondary purified water; S3, performing disinfection treatment on the secondary purified water obtained in step S2 to obtain aquaculture water; The combined biochemical pool in step S2 includes a fixed bed pool and four fluidized bed pools connected in sequence; the fluidized bed pool is provided with a water inlet and a water outlet, and the water inlet is located below the water outlet; the fixed bed pool is provided with an input port and a discharge port, and the input port is located below the discharge port; in the four fluidized bed pools connected in sequence, the water outlet of the previous fluidized bed pool is connected with the water inlet of the next fluidized bed pool through a water passage, and the water outlet of the fluidized bed pool at the tail end is connected with the input port of the fixed bed pool through a water passage.

2. The method for treating aquaculture tail water according to claim 1, characterized in that: Two grid plates are horizontally arranged in the fluidized bed pool, and the two grid plates are located between the water outlet and the water inlet. Fillers are arranged between the two grid plates, and the filling rate of the fillers in the fluidized bed pool is 40-60%.

3. The method for treating aquaculture tail water according to claim 1, characterized in that: Bio-rope is vertically arranged in the fixed bed pool, the porosity of the bio-rope is 70-90%, the number of the bio-rope is 300-500, the distance between any two adjacent bio-rope is 5-15cm, the diameter of the bio-rope is 70-90mm, and the length is 3-4m.

4. The method for treating aquaculture tail water according to claim 1, characterized in that: When the biochemical treatment is performed in step S2, the water inlet flow rate of the combined biochemical pool is 600-1200m 3 / min, the hydraulic retention time of the combined biochemical pool is 10 to 20 minutes, and the aeration rate in the fluidized bed pool is 0.4 to 0.6 m 3 / min, the aeration rate in the fixed bed pool is 0.3-0.5m 3 / min.

5. The method for treating aquaculture tail water according to claim 1, characterized in that: In step S3, the disinfection treatment condition is: the ultraviolet irradiation intensity is not less than 125mW·s / cm 2 , water inlet flow rate is 100~300m 3 / h, hydraulic retention time is 5 to 7s.

6. The method for treating aquaculture tail water according to claim 1, characterized in that: The aquaculture tail water includes drainage from the bottom of the aquaculture pond and drainage from the side of the aquaculture pond. Step S1 includes: The bottom drainage of the culture pond is input into the vertical flow sedimentation tank for sedimentation treatment to separate the sediment and the vertical flow effluent; The drainage from the aquaculture pond is input into a microfiltration machine for filtration treatment to obtain microfiltration effluent and intercepted matter; The obtained intercepted material and vertical effluent are respectively input into a filter press for filter pressing treatment to obtain residue and filter press effluent; The obtained effluent from the filter press is input into the biochemical pool of the moving bed biofilm reactor for biochemical treatment, and the effluent from the biochemical pool of the moving bed biofilm reactor is input into the denitrification tank for denitrification treatment.

7. The method for treating aquaculture tail water according to claim 6, characterized in that: Step S1 also includes: If the aquaculture density in the breeding pond is less than 15kg / m 3 , the effluent from the denitrification tank and the effluent from the microfiltration are combined and the temperature is adjusted to obtain primary purified water; If the aquaculture density of the breeding pond is ≥15kg / m 3 The obtained microfiltration effluent is subjected to protein separation treatment, and the effluent from the denitrification tank is temperature-adjusted and combined with the microfiltration effluent after protein separation to obtain primary purified water.

8. The method for treating aquaculture tail water according to claim 7, characterized in that: In step S1, the water inlet flow rate of the moving bed biofilm reactor biochemical pool is 1.8-3.6m 3 / h, temperature is 18~32℃, hydraulic retention time is 12~24h, aeration volume is 15~20m 3 / min.

9. The method for treating aquaculture tail water according to claim 7, characterized in that: In step S1, the water inlet flow rate of the denitrification tank is 1.6-3.5m 3 / h, the temperature is 18-32℃, and the hydraulic retention time is 12-16h.

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