Aquaculture wastewater treatment device

Abstract

The utility model provides an aquaculture wastewater treatment device. The aquaculture wastewater treatment device comprises a water regulating tank, a front denitrification reactor, a water clarification tank, an efficient denitrification filter tank and a water disinfection tank which are connected in sequence, the pre-denitrification reactor is an up-flow type heterotrophic denitrification reactor; the efficient nitrogen removal filter tank is an autotrophic denitrification nitrogen removal filter tank. After being homogenized, the aquaculture wastewater is subjected to organic matter and nitrogen removal through the heterotrophic denitrification device and the autotrophic denitrification device, and then is disinfected to reach the discharge and reuse standards. Coagulation and flocculation agents do not need to be added, so that the agent adding amount, the power consumption and the air flotation equipment investment are reduced; no additional carbon source needs to be added, the utilization efficiency of the in-situ carbon source of the aquaculture wastewater is improved, and meanwhile, the emission of biochemical sludge is reduced. The device can realize stable up-to-standard treatment of high-concentration aquaculture wastewater under the conditions of low treatment cost, low carbon emission and low operation management difficulty, and provides powerful support for sustainable development of aquaculture industry.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of wastewater treatment, and particularly relates to a device for treating aquaculture wastewater. BACKGROUND

[0002] Aquaculture, as an important agricultural industry, provides abundant aquatic products for human beings. However, with the continuous expansion of the aquaculture scale and the increase of the aquaculture density, while meeting the market demand, a series of problems and challenges in wastewater treatment have also been caused. With the continuous development of the aquaculture industry and the increasingly stringent wastewater discharge standards, the treatment of aquaculture wastewater has become one of the focuses of the industry.

[0003] Aquaculture wastewater needs to be treated by a treatment technology to reduce the content of harmful substances in the wastewater to meet the discharge standards. Common wastewater treatment technologies include biological treatment, physical and chemical treatment, etc. Biological treatment technologies mainly include biological filter, activated sludge method, anaerobic digestion, etc., which convert organic matter into harmless substances through the degradation of microorganisms; physical and chemical treatment technologies include filtration, air flotation, etc., which can effectively remove suspended solids and part of the dissolved substances in the wastewater. In addition, for the problem of high total nitrogen in aquaculture wastewater, the denitrification process is a key link in the treatment.

[0004] As a commonly used denitrification method, heterotrophic denitrification indeed has some problems in practical application. First, the treatment cost is high because of the high nitrate concentration in aquaculture wastewater, and a large amount of external carbon source needs to be added to promote the denitrification process, thereby increasing the treatment cost. Second, a large amount of sludge is generated in the heterotrophic denitrification process, which needs to be additionally treated and disposed, further increasing the operation cost and equipment maintenance cost. In addition, long-term addition of a large amount of external carbon source may also affect the long-term operation stability of the wastewater treatment system and increase the operation risk.

[0005] In addition, with the increasing global attention to carbon emissions, the practice of adding a large amount of external carbon source is also not conducive to the carbon emission management of future wastewater treatment plants. Therefore, the field of aquaculture wastewater treatment urgently needs a new low-cost treatment process to simultaneously solve the problems of treatment cost, effluent standard and carbon emission management, etc. CONTENT OF THE INVENTION

[0006] The embodiment of the application provides a device for treating aquaculture wastewater to solve the problems in the related art, and the technical scheme is as follows:

[0007] In a first aspect, the embodiment of the application provides a device for treating aquaculture wastewater, which comprises a water conditioning tank, a front denitrification reactor, a water clarification tank, an efficient denitrification filter tank and a water disinfection tank connected in sequence.

[0008] The front denitrification reactor is an upflow heterotrophic denitrification reactor; and the high-efficiency denitrification filter is an autotrophic denitrification denitrification filter.

[0009] In one embodiment, an alkalinity feeding device is arranged between the high-efficiency denitrification filter and the water clarifying tank.

[0010] In one embodiment, a first pH probe is arranged between the alkalinity feeding device and the water clarifying tank, and the first pH probe detects the pH value of the water entering the high-efficiency denitrification filter.

[0011] In one embodiment, a second pH probe is arranged after the high-efficiency denitrification filter, and the second pH probe detects the pH value of the water out of the high-efficiency denitrification filter.

[0012] In one embodiment, the alkalinity feeding device is composed of a sodium bicarbonate liquid storage tank, a diaphragm pump and a PLC control unit.

[0013] In one embodiment, the sodium bicarbonate liquid storage tank is connected to the water inlet pipeline of the high-efficiency denitrification filter through the diaphragm pump.

[0014] In one embodiment, the PLC control unit is electrically connected with the first pH probe, the second pH probe and the diaphragm pump respectively, and controls the opening of the diaphragm pump.

[0015] In one embodiment, the front denitrification reactor is filled with denitrification sludge, and the volume of the denitrification sludge is 10%-40% of the volume of the denitrification reactor.

[0016] In one embodiment, the high-efficiency denitrification filter is provided with autotrophic denitrification filter material, the autotrophic denitrification filter material is composed of sulfur, iron and auxiliary materials, and autotrophic denitrification desulfurization bacteria grow on the autotrophic denitrification filter material.

[0017] In one embodiment, the high-efficiency denitrification filter is two or more in parallel.

[0018] In one embodiment, a clear water tank is arranged between the high-efficiency denitrification filter and the water disinfection tank.

[0019] The above technical solution has at least the following advantages or beneficial effects:

[0020] The water product cultivation wastewater treatment device of the utility model discloses, including the water conditioning pool, the pre-denitrification reactor, the water clarification tank, the high -efficient denitrification filter and the water sterilization tank that connect gradually, cultivate wastewater is even after homogeneity and is removed to the organic matter and nitrogen through the heterotrophic denitrification device and autotrophic denitrification device, reaches the standard of discharge and reuse after disinfection again.

[0021] The above summary is intended to illustrate only and is not intended to limit the application in any way. Further aspects, embodiments and features of the present application will be readily apparent to those skilled in the art from the following DETAILED DESCRIPTION, taken in conjunction with the accompanying drawings and the above summary. BRIEF DESCRIPTION OF DRAWINGS

[0022] In the drawings, like numerals refer to like elements throughout the various drawings. The drawings are not necessarily to scale, the drawings are merely intended to depict some of the embodiments disclosed herein. The drawings are included to provide a description of certain embodiments of the present application and are not intended as limitations on the scope of the application.

[0023] Figure 1 A water product cultivation wastewater treatment device is provided for the embodiments of the present application;

[0024] Figure 2 A total nitrogen change graph in front and back wastewater of water product cultivation wastewater is provided;

[0025] 1, water conditioning pool, 2, pre-denitrification reactor, 3, water clarification tank, 4, high-efficiency denitrification filter, 5, water sterilization tank, 6, clear water tank, 7, inclined plate, 8, high-efficiency denitrification filter material, 9, alkalinity feeding device, 10, first pH probe; 11, second pH probe. DETAILED DESCRIPTION

[0026] In the following, only some exemplary embodiments are simply described. As those skilled in the art can recognize, the described embodiments can be modified in various different ways without departing from the spirit or scope of the present application. Therefore, the drawings and the description are considered to be exemplary in nature rather than limiting.

[0027] As Figure 1As shown, the application provides a device for treating aquaculture wastewater, which comprises a water conditioning tank 1, a front denitrification reactor 2, a water clarification tank 3, a high-efficiency denitrification filter 4 and a water disinfection tank 5 connected in sequence.

[0028] The front denitrification reactor 2 is an upflow heterotrophic denitrification reactor; and the high-efficiency denitrification filter 4 is an autotrophic denitrification denitrification filter.

[0029] Traditional water treatment is treated by a single heterotrophic microbial system, and the digestion of carbon source is too high, which often needs additional input of carbon source, and the sludge amount generated is high, and the sludge needs to be cleaned, which all increases the additional water treatment cost.

[0030] The application uses the front denitrification reactor 2 and the high-efficiency denitrification filter 4 in combination, wherein the front denitrification reactor 2 uses the carbon source in the incoming water to carry out the denitrification reaction NO3 - → NO2 - → NO → N2O → N2, and the heterotrophic denitrification is used to complete the simultaneous removal of nitrate and organic matter.

[0031] In one embodiment, the front denitrification reactor 2 is upflow type.

[0032] In one embodiment, the front denitrification reactor 2 is filled with denitrification sludge; and the volume of the denitrification sludge is 10%-40% of the volume of the front denitrification reactor 2. The volume of the denitrification sludge can be set according to the concentration of nitrate in the source of aquaculture wastewater. The residence time of wastewater in the front denitrification reactor 2 is designed according to the concentration of nitrate, but is generally not more than 12h.

[0033] The wastewater enters the bottom of the upflow front denitrification reactor 2, and the suspended solids, organic matter and nitrate nitrogen in the water are removed and decomposed by the denitrification sludge. The upflow front denitrification reactor 2 of the application replaces the original air flotation, and does not need to add the original coagulation and flocculation reagent. The coagulation and flocculation reagent used in the traditional process is cancelled, the amount of reagent added and the power consumption are reduced, and the investment in the equipment of air flotation is reduced. Moreover, the upflow front denitrification reactor 2 has good impact resistance, reduces the water fluctuation by 73%, intercepts the fish manure, feed and the like in the raw water, and the average removal rate of suspended solids is 82.6%. The fish manure, feed and the like after interception are fermented by the upflow front denitrification reactor 2, the soluble COD content is increased, the utilization efficiency of the in-situ carbon source of aquaculture wastewater is improved, and the discharge amount of biochemical sludge is reduced.

[0034] The wastewater treated by the pre-denitrification reactor 2 is treated again by the high-efficiency denitrification filter. The pre-denitrification reactor 2 is an upflow type, and thus the water is discharged from the upper part. The water is treated by the water clarifying tank 3 before entering the high-efficiency denitrification filter 4. The high-speed clarifying tank 3 removes part of the denitrification sludge carried out due to the denitrification gas production, avoids the loss of the denitrification sludge, and avoids the denitrification sludge entering the high-efficiency denitrification filter 4 and mixing with the autotrophic denitrification system to cover the filler and affect the autotrophic denitrification treatment process.

[0035] In an embodiment, the water clarifying tank 3 of the present application is provided with a tilting plate 7. The tilting plate 7 can assist in achieving efficient removal of suspended solids.

[0036] Therefore, the wastewater treated by the water clarifying tank 3 enters the high-efficiency denitrification filter 4 for autotrophic denitrification treatment. In an embodiment, the high-efficiency denitrification filter 4 of the present application is provided with high-efficiency denitrification filler 8, which is autotrophic denitrification filler. The composition of the autotrophic denitrification filler is sulfur, iron, and auxiliary materials. Autotrophic denitrification desulfurization bacteria grow on the autotrophic denitrification filler.

[0037] The autotrophic denitrification desulfurization bacteria reduce the reduced sulfur compounds (such as S 0 , S 2- , S2O3 2- ) as electron donors, and nitrate or nitrite as electron acceptors, to nitrogen.

[0038] (1) Using elemental sulfur as an electron donor

[0039]

[0040] (2) Using sulfide as an electron donor

[0041]

[0042] (3) Using reduced sulfur-containing compounds as an electron donor

[0043]

[0044] The total nitrogen removal load of the high-efficiency denitrification filter 4 can reach 1 kgTN / m 3 -2kgTN / m 3 , and the total nitrogen concentration of the effluent of the high-efficiency denitrification filter 4 can be reduced to below 3 mg / L. In the case of an influent TN concentration of 100 mg / L and an effluent TN requirement of less than 5 mg / L, the average denitrification load of the high-efficiency denitrification filter 4 is 1.86 kgTN / m 3 , which is 20% higher than the heterotrophic denitrification load.

[0045] In the present embodiment, the high-efficiency denitrification filter 4 adopts the top-in and bottom-out form, and the water from the water clarifying tank 3 enters the top of the high-efficiency denitrification filter 4.

[0046] In one embodiment, the high-efficiency denitrification filter 4 is provided with an alkalinity feeding device 9 between the high-efficiency denitrification filter 4 and the water clarifying tank 3. The optimal pH for the high-efficiency denitrification filter material 8 of the high-efficiency denitrification filter 4 and the autotrophic denitrification desulfurization bacteria working therein is about 7-8, and thus the pH is adjusted by the alkalinity feeding device 9 provided before the water enters the high-efficiency denitrification filter 4.

[0047] In one embodiment, the alkalinity feeding device 9 is composed of a sodium bicarbonate liquid storage tank, a diaphragm pump and a PLC control unit.

[0048] In one embodiment, the sodium bicarbonate liquid storage tank is connected to the water inlet pipeline of the high-efficiency denitrification filter 4 through the diaphragm pump.

[0049] The diaphragm pump links the sodium bicarbonate liquid storage tank, and the diaphragm pump is controlled by the PLC unit. When the pH value of the water inlet is less than 7 and the pH value of the water outlet is less than 6, the PLC controls the diaphragm pump of the alkalinity feeding device 9 to automatically start, and sodium bicarbonate is added to the water inlet of the high-efficiency denitrification filter 4 to ensure the alkalinity required by the autotrophic denitrification.

[0050] In one embodiment, the concentration of the sodium bicarbonate concentrated solution in the storage tank is 30%.

[0051] Therefore, in one embodiment, the alkalinity feeding device 9 is further provided with a first pH probe 10 between the alkalinity feeding device 9 and the water clarifying tank 3, and the first pH probe 10 detects the pH value of the water inlet of the high-efficiency denitrification filter 4.

[0052] In one embodiment, a second pH probe 11 is provided after the high-efficiency denitrification filter 4, and the second pH probe 11 detects the pH value of the water outlet of the high-efficiency denitrification filter 4.

[0053] The PLC control unit is electrically connected with the first pH probe 10 and the second pH probe 11 respectively; the first pH probe 10 and the second pH probe 11 detect the pH of the water inlet and the water outlet respectively, and the PLC control unit controls the opening and closing of the diaphragm pump to control the addition of sodium bicarbonate in the sodium bicarbonate liquid storage tank according to the pH value; and the pH of the water inlet of the high-efficiency denitrification filter 4 is controlled to be between 7.0-8.0.

[0054] In one embodiment, the high-efficiency denitrification filter 4 is two or more in parallel. The parallel use of the high-efficiency denitrification filter 4 can increase the processing capacity.

[0055] The content of nitrate in the water treated by the high-efficiency denitrification filter 4 is already lower than 3 mg / L, and the effluent is subjected to disinfection by adding sodium hypochlorite in the chlorinated water disinfection tank 5. The effluent is disinfected by adding sodium hypochlorite in the chlorinated water disinfection tank 5 to meet the standard of coliform bacteria discharge, and the residual ammonia nitrogen in the wastewater is removed by the breakpoint chlorination method, so that the total nitrogen in the effluent is further reduced to less than 3 mg / L.

[0056] The effluent of the chlorinated water disinfection tank 5 is partially discharged and partially reused as aquaculture water. Through the treatment of the system, the reuse rate of aquaculture water can be increased by 23.33%, from 75% to 92.5%.

[0057] In an embodiment, a clear water tank 6 is further arranged between the high-efficiency denitrification filter 4 and the water disinfection tank 5. The clear water tank 6 can store the purified water and meet the contact time of chlorine and water in the chlorinated water disinfection tank 5.

[0058] Because the feed and temperature required for the growth cycle of aquaculture, the pollutant concentration and difference of the effluent of each workshop are obvious, a water conditioning tank 1 is arranged before the pre-denitrification reactor 2. The effluent of the production workshop is first subjected to the water conditioning tank 1 before entering the pre-denitrification reactor 2. Through the water conditioning tank 1, the aquaculture wastewater in different growth environments in different aquaculture workshops is fully mixed to realize the homogenization of concentration and temperature. The volume of the water conditioning tank 1 is designed according to the treated water quantity and the layout of the aquaculture workshop.

[0059] The residence time of the wastewater in the water conditioning tank 1 is 0.5-8 h, and it is not less than 0.5 h. Then the effluent of the water conditioning tank 1 enters the bottom of the upflow pre-denitrification reactor 2.

[0060] The process of treating wastewater by the aquaculture wastewater treatment device is as follows:

[0061] The effluent of the production workshop is first subjected to the water conditioning tank 1; through the water conditioning tank 1, the aquaculture wastewater in different growth environments in different aquaculture workshops is fully mixed and homogenized; the hydraulic retention time is usually 0.5-8 h. The effluent of the water conditioning tank 1 enters the bottom of the upflow pre-denitrification reactor 2, and the suspended solids, organic matter and nitrate nitrogen in the water are removed and decomposed by the denitrification sludge. The upflow pre-denitrification reactor 2 discharges water from the upper part, and the effluent is sent to the high-speed water clarifier 3 through a pipeline; the high-speed water clarifier 3 removes part of the denitrification sludge carried out by the denitrification gas; the effluent of the high-speed water clarifier 3 is sent to the high-efficiency denitrification filter 4 through a pipeline. The filter inlet water contains a pH probe 10 and an alkalinity feeding device 9, and the pH of the inlet water of the high-efficiency denitrification filter 4 is controlled to be between 7.0-8.0 by controlling the addition of alkalinity. The high-efficiency denitrification filter 4 is in the form of upflow and downflow; in the high-efficiency denitrification filter 4, the average total nitrogen removal rate is 75%, and the total nitrogen removal load range is 1 kgTN / m 3 -2 kgTN / m 3The nitrate content of the effluent is less than 3 mg / L, and the effluent enters the chlorinated water disinfection tank 5 after passing through the clean water tank 6. In the chlorinated water disinfection tank 5, the effluent is disinfected by adding sodium hypochlorite to meet the standard of coliform bacteria discharge, and the residual ammonia nitrogen in the wastewater is removed by referring to the breakpoint chlorination method, so that the total nitrogen of the effluent is further reduced to less than 3 mg / L. The effluent of the chlorinated water disinfection tank 5 is partially discharged and partially reused as aquaculture water. Through the device system, the aquaculture water reuse rate can be increased by 23.33%, from 75% to 92.5%; the total nitrogen content in the wastewater changes as shown in Figure 2

[0062] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, different embodiments or examples described in the specification and the features of different embodiments or examples can be combined and combined by those skilled in the art without contradiction.

[0063] In addition, the terms "first", "second" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include at least one feature. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise specifically limited.

[0064] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of various changes or replacements within the technical scope disclosed in the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.​

Claims

1. An apparatus for treating aquaculture wastewater, characterized by comprising: The water conditioning tank (1), the pre-denitrification reactor (2), the water clarifying tank (3), the high-efficiency denitrification filter tank (4) and the water disinfection tank (5) are sequentially connected. The pre-denitrification reactor (2) is an upflow heterotrophic denitrification reactor, and the high-efficiency denitrification filter tank (4) is an autotrophic denitrification denitrification filter tank. The pre-denitrification reactor (2) is filled with denitrification sludge. The volume of the denitrification sludge is 10%-40% of the volume of the denitrification reactor. The high-efficiency denitrification filter tank (4) is provided with autotrophic denitrification filter material, the composition of the autotrophic denitrification filter material is sulfur, iron and auxiliary materials, and autotrophic denitrification desulfurization bacteria grow on the autotrophic denitrification filter material.

2. The device for treatment of wastewater from aquaculture according to claim 1, characterized in that The high-efficiency denitrification filter tank (4) and the water clarifying tank (3) are provided with an alkalinity feeding device (9).

3. An aquaculture wastewater treatment apparatus according to claim 2, characterised in that, The alkalinity feeding device (9) and the water clarifying tank (3) are further provided with a first pH probe (10), and the first pH probe (10) detects the pH value of the water inlet of the high-efficiency denitrification filter tank (4).

4. An aquaculture wastewater treatment apparatus according to claim 3, characterised in that, The high-efficiency denitrification filter tank (4) is provided with a second pH probe (11), and the second pH probe (11) detects the pH value of the water outlet of the high-efficiency denitrification filter tank (4).

5. An aquaculture wastewater treatment apparatus according to claim 4, characterised in that, The alkalinity feeding device (9) is composed of a sodium bicarbonate liquid storage tank, a diaphragm pump and a PLC control unit.

6. An aquaculture wastewater treatment apparatus according to claim 5, characterised in that, The sodium bicarbonate liquid storage tank is connected with the water inlet pipeline of the high-efficiency denitrification filter tank (4) through the diaphragm pump, and the PLC control unit is electrically connected with the first pH probe (10), the second pH probe (11) and the diaphragm pump respectively, and controls the opening of the diaphragm pump.

7. The device for treatment of wastewater from aquaculture according to claim 1, characterized in that, The high-efficiency denitrification filter tank (4) is two or more in parallel.

8. The device for treatment of wastewater from aquaculture according to claim 1, characterized in that, The high-efficiency denitrification filter tank (4) and the water disinfection tank (5) are further provided with a clean water tank (6).

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