Device and method for treating ammonia-nitrogen wastewater with high CODCr (Chemical Oxygen Demand) by coupling electrochemical enhanced activated carbon with anaerobic ammonia oxidation

Abstract

The invention relates to a device and method for treating high CODCr ammonia-nitrogen wastewater through coupling of electrochemically enhanced activated carbon and anaerobic ammonia oxidation, and relates to the technical field of wastewater treatment.The device comprises a sedimentation tank, an electrochemical reaction assembly and an anaerobic ammonia oxidation reaction mechanism which are sequentially arranged; according to the method, by combining physical precipitation, electrochemistry and anaerobic ammonia oxidation reaction with water quality characteristics of high ammonia nitrogen and CODCr in the livestock and poultry wastewater, refractory organic matters in the wastewater are removed by utilizing an electrochemical device, and substances such as ammonia nitrogen and the like in the wastewater are removed in cooperation with a biochar reinforced anaerobic ammonia oxidation system; compared with a traditional wastewater treatment system, the system has the advantages that the treatment time is greatly shortened, the operation cost is greatly reduced, and nitrogen and carbon removal of livestock and poultry breeding wastewater is finally realized.

Description

Technical Field

[0001] The present invention relates to the field of wastewater treatment technology, in particular to an electrochemically enhanced activated carbon coupled anaerobic ammonia oxidation method for treating high COD Cr Device and method for treating ammonia nitrogen wastewater. Background Art

[0002] With the continuous improvement of people's living standards, people's demand for meat products is increasing. The domestic breeding model has gradually changed to large-scale, high-density intensive livestock and poultry breeding. Under this model, high-concentration livestock and poultry breeding wastewater has become the main source of pollution in many areas of my country, making the contradiction between the development of livestock and poultry breeding and environmental pollution increasingly prominent. According to relevant data surveys, the chemical oxygen demand (COD) in livestock and poultry breeding wastewater is Cr ) content is about 10 million tons, ammonia nitrogen (NH4 + -N) is about 120,000 tons, total nitrogen (TN) is about 600,000 tons, and total phosphorus (TP) is about 120,000 tons. Each pollutant accounts for 46.71%, 12.5%, 19.74% and 37.5% of the water pollutant emissions. It can be seen that livestock and poultry breeding wastewater has become one of the main sources of water pollution emissions in the country.

[0003] Compared with domestic wastewater, livestock and poultry wastewater contains high concentrations of COD, nitrogen, phosphorus, suspended solids (SS) and other pollutants, and the pollution load is very high. At present, there are two main methods for treating pig farm biogas: one is natural treatment, the most common of which are biological pond method and artificial wetland method; the other is industrial treatment technology, the most common of which are UASB process, SBR process, A / O process, etc. However, the treatment effect of livestock and poultry wastewater treatment processes at home and abroad at this stage is not very ideal, especially it is difficult to effectively reduce the total nitrogen and COD in the aquaculture wastewater. Cr After the removal is in place, especially in the A / O process, the subsequent aerobic treatment is prone to acidification, and a large amount of alkali needs to be added to maintain the normal operation of the system. The construction and operation costs are high. Therefore, it is urgent to develop a wastewater treatment system with low operating costs and high efficiency in nitrogen and carbon removal to achieve long-term and stable treatment of livestock and poultry wastewater. Summary of the invention

[0004] In order to improve the treatment efficiency of livestock and poultry wastewater and save costs, the present invention provides an electrochemically enhanced activated carbon coupled anaerobic ammonia oxidation method for treating high COD Cr Device and method for treating ammonia nitrogen wastewater.

[0005] In the first aspect, the present application provides an electrochemically enhanced activated carbon coupled anaerobic ammonia oxidation process for treating high COD Cr The device for treating ammonia nitrogen wastewater adopts the following technical solution:

[0006] An electrochemically enhanced activated carbon coupled anaerobic ammonium oxidation method for treating high CODCr The device for treating ammonia nitrogen wastewater comprises a sedimentation tank, an electrochemical reaction component and an anaerobic ammonia oxidation reaction mechanism which are arranged in sequence. The sedimentation tank is used for solid-liquid separation of livestock and poultry wastewater, the electrochemical reaction component is used for decarbonation pretreatment of livestock and poultry wastewater, and the anaerobic ammonia oxidation reaction mechanism is used for removing ammonia nitrogen from the pretreated livestock and poultry wastewater.

[0007] By adopting the above technical solution, the sedimentation tank physically precipitates the livestock and poultry wastewater to remove solid waste in the wastewater. The precipitated wastewater enters the electrochemical component for electrochemical reaction to achieve decarbonization pretreatment, thereby reducing the COD in the wastewater. Cr , providing a suitable growth environment for the anaerobic ammonium oxidizing bacteria at the back end to enhance the treatment efficiency of the anaerobic ammonium oxidizing reaction mechanism. The effluent from the electrochemical reaction component enters the anaerobic ammonium oxidizing reaction mechanism for anaerobic ammonium oxidizing reaction. The remaining COD in the wastewater Cr The ammonia nitrogen is reduced to nitrogen gas, and the ammonia nitrogen is converted into nitrogen gas in the anaerobic ammonium oxidation reaction, and a part of nitrate nitrogen is produced, thereby reducing the COD in livestock and poultry wastewater. Cr and ammonia nitrogen content in the wastewater. By first using the electrochemical reaction component to remove the difficult-to-degrade organic matter in the wastewater, and then cooperating with the anaerobic ammonia oxidation mechanism to remove the ammonia nitrogen in the wastewater, it saves treatment time and operating costs compared to traditional wastewater treatment systems, thereby improving the treatment efficiency of livestock and poultry wastewater and reducing treatment costs.

[0008] Optionally, the electrochemical reaction component includes:

[0009] A reaction tank, the reaction tank is connected to a sedimentation tank, an adsorption layer is arranged in the reaction tank, the adsorption layer divides the reaction tank into an anode chamber and a cathode chamber, the anode chamber is connected to the sedimentation tank through an inlet pipe, and the cathode chamber is connected to an anaerobic ammonia oxidation reaction mechanism through an outlet pipe;

[0010] an anode plate, wherein the anode plate is disposed in the anode cavity;

[0011] The cathode plate is arranged in the cathode cavity, and the anode plate and the cathode plate are connected through an external circuit.

[0012] By adopting the above technical solution, the precipitated wastewater enters the reaction tank through the water inlet pipe. In the anode plate, which is the point interval where oxygen is precipitated, water discharges on the surface of the anode plate to generate hydroxyl radicals (·OH). The organic matter in the wastewater is converted into low-harmful or harmless small molecules under the action of ·OH, and the cations precipitated from the anode plate are adsorbed into the adsorption layer, thereby reducing the COD in the effluent. Cr , providing a suitable growth environment for the back-end anaerobic ammonium-oxidizing bacteria to enhance the treatment efficiency of the anaerobic ammonium-oxidizing reaction mechanism.

[0013] Optionally, the anaerobic ammonium oxidation reaction mechanism comprises:

[0014] The reactor is an upflow reactor and has a water inlet at the bottom, one end of the water outlet pipe away from the cathode chamber is connected to the water inlet, a three-phase separator is provided on the top of the reactor, the three-phase separator is connected to a precipitator, and the precipitator is externally connected to a water outlet tank;

[0015] Biological filler, the biological filler includes anaerobic ammonium oxidation granular sludge and biochar, the anaerobic ammonium oxidation granular sludge and biochar are filled in the reactor and used for biological treatment of livestock and poultry wastewater;

[0016] an aeration assembly, the aeration assembly being disposed in the reactor and being used for intermittent aeration;

[0017] The thermostatic component is arranged on the reactor and is used to control the reactor to maintain a constant temperature.

[0018] By adopting the above technical solution, wastewater flows from the reaction tank to the reactor through the outlet pipe. Ammonia oxidizing bacteria, anaerobic ammonia oxidizing bacteria and denitrifying bacteria are enriched in the anaerobic ammonia oxidizing granular sludge. The dissolved oxygen content in the reactor is maintained within a certain concentration range through the aeration component. The temperature of the reactor is adjusted by the constant temperature component to meet the suitable growth environment of the bacterial flora. Part of the ammonia nitrogen in the wastewater is converted into nitrite nitrogen under the action of ammonia oxidizing bacteria, which serves as the substrate for the next step of anaerobic ammonia oxidation; anaerobic ammonia oxidizing bacteria can convert the remaining ammonia nitrogen and nitrite nitrogen into nitrogen gas, while producing part of nitrate nitrogen; in addition, the porous surface structure of biochar provides good adsorption sites for microorganisms, which is conducive to the enrichment of microorganisms and promotes the secretion of extracellular polymers to form biofilms. In addition, the aromatic proteins and humus in the extracellular polymers can serve as electron transfer media to strengthen the mass transfer drive between the anaerobic ammonia oxidizing bacteria and the functional groups on the surface of biochar, thereby strengthening the extracellular electron transfer capacity of the anaerobic ammonia oxidizing bacteria; the denitrifying bacteria in the sludge can use the remaining COD Cr Nitrate nitrogen is reduced to nitrogen gas, which further improves the removal of nitrogen and carbon in the water body, and finally achieves denitrification and decarbonization of wastewater, thereby improving the treatment efficiency of livestock and poultry wastewater; compared with traditional nitrification-denitrification, it reduces the energy consumption of aeration, mixed liquor reflux, etc., and the total power consumption is reduced; in this process stage, no external carbon source is required for denitrification, and the anaerobic ammonia-oxidizing bacteria with autotrophic nutritional form grow slowly, which can reduce sludge production and greatly reduce the subsequent sludge disposal costs, thereby reducing costs.

[0019] Optionally, the aeration assembly includes an aeration plate, an aeration pump and a dissolved oxygen detector, the aeration plate is arranged in the reactor and located above the water inlet, the output end of the aeration pump is connected to the aeration plate, and the detection element of the dissolved oxygen detector extends into the reactor and is located above the aeration plate and is used to detect the dissolved oxygen content in the reactor.

[0020] By adopting the above technical solution, the detection element detects the dissolved oxygen content in the reactor. When the dissolved oxygen concentration exceeds the limit, the aeration pump controls the opening and closing of the aeration disk to control the dissolved oxygen conditions in the reactor to meet the growth environment suitable for the bacterial flora, thereby improving the treatment efficiency of livestock and poultry wastewater.

[0021] Optionally, the constant temperature component includes a water bath interlayer, a circulation pool, a water supply pipe and a return water pipe, the water bath interlayer is sleeved on the outer wall of the reactor, the circulation pool is a constant temperature water bath, both ends of the water supply pipe are respectively connected to the circulation pool and the water bath interlayer and are located at the bottom of the water bath interlayer, and both ends of the return water pipe are respectively connected to the water bath interlayer and the circulation pool and are located at the top of the water bath interlayer.

[0022] By adopting the above technical scheme, the water bath temperature in the circulation pool is specified according to the required temperature, and the constant temperature water is introduced into the water bath interlayer through the water supply pipe. The water in the water bath interlayer flows back to the circulation pool through the return pipe for circulation heating. In this way, the temperature control of the reactor is achieved to meet the growth environment suitable for the bacterial flora, thereby improving the treatment efficiency of livestock and poultry wastewater.

[0023] Optionally, the adsorption layer is selected from at least one of activated carbon, zeolite and diatom mud, and the thickness of the adsorption layer is 10-30 cm; the anode plate is a lead dioxide plate, and the cathode plate is graphite felt.

[0024] By adopting the above technical solution, the electrode materials are preferably used as cathode plates and anode plates to improve the efficiency of electrochemical reaction, thereby increasing the COD content in wastewater. Cr The treatment efficiency is improved. The lead ions precipitated from the lead dioxide anode plate flow to the adsorption layer and adhere to the adsorption layer, thereby reducing the content of lead ions in the effluent and improving the water quality of the effluent from the reaction tank.

[0025] In the second aspect, the present application provides an electrochemically enhanced activated carbon coupled anaerobic ammonia oxidation process for treating high COD Cr The method for treating ammonia nitrogen wastewater adopts the following technical scheme:

[0026] An electrochemically enhanced activated carbon coupled anaerobic ammonium oxidation method for treating high COD Cr The method for treating ammonia nitrogen wastewater comprises the following steps:

[0027] S1, introducing livestock and poultry wastewater into a sedimentation tank for sedimentation to remove solid waste in the wastewater;

[0028] S2, the precipitated wastewater enters the anode cavity through the water inlet pipe, the wastewater flows in the reaction tank, the power of the external circuit is turned on, the anode plate and the cathode plate work to oxidize the organic matter in the wastewater, and the adsorption layer adsorbs the ions precipitated on the anode plate to reduce the COD in the livestock and poultry wastewater Cr Content;

[0029] S3, adding biological filler into the reactor, starting the constant temperature component to keep the reactor at a constant temperature, and measuring the COD Cr The content of COD Cr When the content is ≤300 mg / L, the wastewater in the cathode chamber is introduced into the reactor through the outlet pipe, and the dissolved oxygen detector is started. When the dissolved oxygen content in the reactor is lower than 0.2 mg / L, the aeration pump is started to provide aeration. When the dissolved oxygen exceeds 0.5 mg / L due to continuous aeration, the aeration pump is turned off to maintain the dissolved oxygen in the reactor in the range of 0.2-0.5 mg / L.

[0030] S4, livestock and poultry wastewater undergoes biological reaction in the reactor, the three-phase separator separates the treated mixture, and the treated water passes through the sedimentator and enters the water outlet tank for collection.

[0031] By adopting the above technical solution, the livestock and poultry wastewater is physically precipitated to remove solid waste, and then enters the reaction tank for electrochemical reaction to reduce COD in the wastewater. Cr The content of organic matter is not pursued at this stage, and the COD Cr Less than 300 mg / L is taken as the end point of the electrolysis reaction, which greatly saves energy consumption; finally, the wastewater enters the reactor, and by adjusting the temperature and dissolved oxygen content, the growth environment of ammonia oxidizing bacteria, anaerobic ammonia oxidizing bacteria and denitrifying bacteria in the reactor is met. The dissolved oxygen is mainly used for the growth and utilization of heterotrophic denitrifying bacteria, allowing heterotrophic denitrifying bacteria to consume the remaining COD in the wastewater. Cr After the dissolved oxygen is consumed by heterotrophic bacteria, it provides a good growth environment for anaerobic ammonium oxidizing bacteria and further purifies the water quality; part of the ammonia nitrogen in the wastewater is converted into nitrite nitrogen under the action of ammonia oxidizing bacteria, which serves as the substrate for the next step of anaerobic ammonium oxidation; anaerobic ammonium oxidizing bacteria can convert the remaining ammonia nitrogen and nitrite nitrogen into nitrogen gas, while producing some nitrate nitrogen; in addition, biochar can significantly promote the secretion of extracellular polymers, and the increased extracellular polymers strengthen the mass transfer drive between the anaerobic ammonium oxidizing bacteria and the functional groups on the surface of biochar, and enhance the extracellular electron transfer capacity of the anaerobic ammonium oxidizing bacteria; denitrifying bacteria in the sludge can use the remaining COD Cr The nitrate nitrogen is reduced to nitrogen gas, which further improves the removal of nitrogen and carbon in the water body, and finally achieves denitrification and decarbonization of wastewater, thereby improving the treatment efficiency of livestock and poultry wastewater. The three-phase separator separates the treated mixture, and the treated water passes through the sedimentator and enters the water outlet tank for collection.

[0032] Compared with traditional nitrification-denitrification, the energy consumption of aeration and mixed liquor reflux is reduced, and the total power consumption is reduced; in this process section, no external carbon source is required for denitrification, and the anaerobic ammonia-oxidizing bacteria with autotrophic nutritional form grow slowly, which can reduce sludge production and greatly reduce subsequent sludge disposal costs, thereby reducing costs.

[0033] Optionally, the biochar in S3 is added once, and the concentration of the biochar added is 8 g / L, and the particle size is 100 μm.

[0034] By adopting the above technical scheme, optimizing the biochar and particle size and addition concentration, and adding the biochar at one time, the biochar is fully utilized to promote the secretion of more extracellular polymers by anaerobic ammonia-oxidizing bacteria. The increased extracellular polymers strengthen the mass transfer drive between the anaerobic ammonia-oxidizing bacteria and the functional groups on the surface of the biochar, and strengthen the intracellular electron transfer capacity of the anaerobic ammonia-oxidizing bacteria. At the same time, the increased extracellular polymer content enhances the ability of cells to recognize and adhere to extracellular mechanisms, strengthens the structural integrity of anaerobic ammonia-oxidizing sludge, and can effectively reduce the loss of anaerobic ammonia-oxidizing sludge, thereby reducing energy consumption and costs, while improving wastewater treatment efficiency.

[0035] Optionally, the effective volume of the reactor is 2 L, and the amount of anaerobic ammonium-oxidation granular sludge inoculated in the reactor is 20.54±0.75 g.

[0036] By adopting the above technical solution, the inoculated sludge concentration is optimized, so that the energy consumption and cost can be reduced while the wastewater treatment efficiency is improved.

[0037] Optionally, the working conditions in the reactor are: pH 7-8, temperature 35±1°C, and dissolved oxygen content 0.2-0.5 mg / L.

[0038] By adopting the above technical solution, the pH, temperature and dissolved oxygen content in the reactor are controlled to meet the growth environment suitable for each bacterial community in the reactor. The dissolved oxygen is mainly used for the growth and utilization of heterotrophic denitrifying bacteria, allowing the heterotrophic denitrifying bacteria to consume the remaining COD in the wastewater. Cr After the dissolved oxygen is consumed by heterotrophic bacteria, it provides a good growth environment for anaerobic ammonia-oxidizing bacteria and further purifies the water quality, thereby improving the treatment efficiency of livestock and poultry wastewater.

[0039] In summary, the present application includes at least one of the following beneficial technical effects:

[0040] 1. The sedimentation tank physically precipitates the livestock and poultry wastewater to remove solid waste in the wastewater. The precipitated wastewater enters the electrochemical component for electrochemical reaction to achieve decarbonization pretreatment, thereby reducing the COD in the wastewater. Cr, providing a suitable growth environment for the anaerobic ammonium oxidizing bacteria at the back end to enhance the treatment efficiency of the anaerobic ammonium oxidizing reaction mechanism. The effluent from the electrochemical reaction component enters the anaerobic ammonium oxidizing reaction mechanism for anaerobic ammonium oxidizing reaction. The remaining COD in the wastewater Cr The ammonia nitrogen is reduced to nitrogen gas, and the ammonia nitrogen is converted into nitrogen gas in the anaerobic ammonium oxidation reaction, and a part of nitrate nitrogen is produced, thereby reducing the COD in livestock and poultry wastewater. Cr and ammonia nitrogen content in the wastewater. By first using the electrochemical reaction component to remove the difficult-to-degrade organic matter in the wastewater, and then cooperating with the anaerobic ammonia oxidation mechanism to remove the ammonia nitrogen in the wastewater, it saves treatment time and operating costs compared to traditional wastewater treatment systems, thereby improving the treatment efficiency of livestock and poultry wastewater and reducing treatment costs.

[0041] 2. This method combines physical precipitation + electrochemistry + anaerobic ammonium oxidation reaction to target high ammonia nitrogen and COD in livestock and poultry wastewater. Cr According to the water quality characteristics of the wastewater, an electrochemical device is used to remove difficult-to-degrade organic matter in the wastewater, and a biochar-enhanced anaerobic ammonia oxidation system is used to remove substances such as ammonia nitrogen in the wastewater. Compared with traditional wastewater treatment systems, this system greatly shortens the processing time and operating costs, and ultimately achieves denitrification and carbon removal of livestock and poultry wastewater.

[0042] 3. In the electrochemical reaction tank, use constant voltage to find COD Cr The balance between degradation efficiency and electrolysis time can reduce the occurrence of side reactions. In addition, this stage does not pursue the complete mineralization of organic matter, and the COD Cr Less than 300 mg / L is taken as the end point of the electrolysis reaction, which greatly saves energy consumption.

[0043] 4. In the anaerobic ammonium oxidation reaction, compared with traditional nitrification-denitrification, the energy consumption of aeration, mixed liquor reflux, etc. is reduced, and the total power consumption is reduced; in this process stage, no external carbon source is required for denitrification, and the anaerobic ammonium oxidizing bacteria with autotrophic nutritional form grow slowly, which can reduce sludge production and greatly reduce subsequent sludge disposal costs; in addition, the biochar added to the reactor can significantly promote the secretion of extracellular polymers, and the increased extracellular polymers can enhance the transfer of extracellular electrons, enhance the ability of cells to recognize and adhere to the extracellular matrix, strengthen the structural integrity of the anaerobic ammonium oxidation sludge, and effectively reduce the loss of anaerobic ammonium oxidation sludge, so as to achieve stable and efficient wastewater treatment in the reactor. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 It is a schematic diagram of the overall structure of this application.

[0045] Figure numerals: 1. sedimentation tank; 11. water inlet pump; 2. electrochemical reaction component; 21. reaction tank; 22. anode plate; 23. cathode plate; 24. adsorption layer; 25. anode chamber; 251. water inlet pipe; 26. cathode chamber; 261. water outlet pipe; 27. drive pump; 3. anaerobic ammonia oxidation reaction mechanism; 31. reactor; 32. biological filler; 321. anaerobic ammonia oxidation granular sludge; 322. biochar; 33. aeration component; 331. aeration disk; 332. aeration pump; 333. dissolved oxygen detector; 34. constant temperature component; 341. water bath interlayer; 342. circulation tank; 343. water pipe; 344. return pipe; 345. water pump; 35. three-phase separator; 36. precipitator; 37. water outlet tank. DETAILED DESCRIPTION

[0046] The following is combined with Figure 1 This application is described in further detail.

[0047] The present application discloses an electrochemically enhanced activated carbon coupled anaerobic ammonia oxidation method for treating high COD Cr Device and method for treating ammonia nitrogen wastewater.

[0048] The following examples are only used to illustrate the present invention and should not be construed as limiting the scope of the present invention. Specific conditions not specified in the examples are carried out according to conventional conditions or conditions recommended by the manufacturer. Reagents or instruments used without indicating the manufacturer are conventional products that can be purchased commercially.

[0049] 1. Implementation

[0050] Example 1

[0051] This embodiment discloses an electrochemically enhanced activated carbon coupled anaerobic ammonia oxidation method for treating high COD Cr Ammonia nitrogen wastewater treatment plant.

[0052] An electrochemically enhanced activated carbon coupled anaerobic ammonium oxidation method for treating high COD Cr The device for treating ammonia nitrogen wastewater comprises a sedimentation tank 1, an electrochemical reaction component 2 and an anaerobic ammonia oxidation reaction mechanism 3 which are arranged in sequence.

[0053] The sedimentation tank 1 adopts the vertical flow sedimentation tank in the prior art. The sedimentation tank 1 is used for solid-liquid separation of livestock and poultry wastewater. The bottom end of the sedimentation tank 1 is the water inlet end, and the water inlet end is connected to the water inlet pump 11 for pumping wastewater. The sedimentation tank 1 has a water outlet on the outer wall at the top. In this embodiment, the effective volume of the sedimentation tank 1 is 2L, and the hydraulic retention time is 24-48h.

[0054] The electrochemical reaction component 2 is used for decarbonization pretreatment of livestock and poultry wastewater. The electrochemical reaction component 2 includes a reaction tank 21, an anode plate 22 and a cathode plate 23. The effective volume of the reaction tank 21 is 2L. The reaction tank 21 is connected to the water outlet of the sedimentation tank 1. A vertical adsorption layer 24 is provided in the reaction tank 21. The adsorption layer 24 divides the reaction tank 21 into an anode chamber 25 and a cathode chamber 26. The adsorption layer 24 is a plate-like structure made of activated carbon, and the thickness of the adsorption layer 24 is 20 cm. The anode chamber 25 is connected to the water outlet of the sedimentation tank 1 through an inlet pipe 251, and a filter is provided in the inlet pipe 251. The cathode chamber 26 is connected to the anaerobic ammonia oxidation reaction mechanism 3 through an outlet pipe 261. A driving pump 27 is provided on the inlet pipe 251 and the outlet pipe 261. The inlet pump 11 and the driving pump 27 are both peristaltic pumps.

[0055] The anode plate 22 is arranged in the anode cavity 25, and the anode plate 22 is a lead dioxide plate. The cathode plate 23 is arranged in the cathode cavity 26, and the cathode plate 23 is graphite felt. The anode plate 22 and the cathode plate 23 are connected through an external circuit; after the wastewater enters the anode cavity 25 through the water inlet pipe 251, it can flow in the anode cavity 25 and the cathode cavity 26 through the adsorption layer 24.

[0056] The anaerobic ammonia oxidation reaction mechanism 3 includes a reactor 31, a biological filler 32, an aeration component 33 and a constant temperature component 34. The reactor 31 is an upflow reactor. The effective volume of the reactor 31 is 2L, the height-to-diameter ratio is 5:1, and the hydraulic retention time is 24-48h. The bottom of the reactor 31 is provided with a water inlet, and the end of the outlet pipe 261 away from the cathode chamber 26 is connected to the water inlet. The top of the reactor 31 is provided with a three-phase separator 35, one end of the three-phase separator 35 is connected to a precipitator 36, and the other end of the three-phase separator 35 is connected to the external environment. The side wall of the precipitator 36 has an overflow port, and the overflow port is externally connected to a water outlet tank 37.

[0057] The biological filler 32 includes anaerobic ammonium oxidation granular sludge 321 and biochar 322 . The anaerobic ammonium oxidation granular sludge 321 and biochar 322 are filled in the reactor 31 and used for biological treatment of livestock and poultry wastewater.

[0058] The aeration assembly 33 is arranged in the reactor 31 and is used for intermittent aeration. The aeration assembly 33 includes an aeration plate 331, an aeration pump 332 and a dissolved oxygen detector 333. The aeration plate 331 is arranged in the reactor 31 and is located above the water inlet. The output end of the aeration pump 332 is connected to the aeration plate 331. The dissolved oxygen detector 333 is arranged on the reactor 31 and the detection element extends into the reactor 31 and is located above the aeration plate 331. The dissolved oxygen detector 333 is used to detect the dissolved oxygen content in the reactor 31. When the dissolved oxygen concentration exceeds the limit, the aeration plate 331 is opened and closed by the aeration pump 332 to realize the control of the dissolved oxygen conditions in the reactor 31.

[0059] The thermostatic component 34 is arranged on the reactor 30 and is used to control the reactor 30 to maintain a constant temperature. The thermostatic component 34 includes a water bath interlayer 341, a circulation pool 342, a water pipe 343 and a return pipe 344. The water bath interlayer 341 is sleeved on the outer wall of the reactor 31. The circulation pool 342 is a constant temperature water bath with adjustable temperature. The two ends of the water pipe 343 are respectively connected to the circulation pool 342 and the water bath interlayer 341 and are located at the bottom of the water bath interlayer 341. A water pump 345 is provided on the water pipe 343, and the water pump 345 is also a peristaltic pump. The two ends of the return pipe 344 are respectively connected to the water bath interlayer 341 and the circulation pool 342 and are located at the top of the water bath interlayer 341.

[0060] An electrochemically enhanced activated carbon coupled anaerobic ammonium oxidation method for treating high COD Cr The method for treating ammonia nitrogen wastewater, using the above device, comprises the following steps:

[0061] S1, introducing the livestock and poultry wastewater raw liquid into sedimentation tank 1 for sedimentation to remove solid waste in the wastewater, and the hydraulic retention time in sedimentation tank 1 is 36 hours.

[0062] S2, the precipitated wastewater enters the anode chamber 25 through the water inlet pipe, the wastewater flows in the reaction tank, the power supply of the external circuit is turned on, a constant voltage of 3-4V is used, the anode plate 22 and the cathode plate 23 work to oxidize the organic matter in the wastewater, and the adsorption layer 24 adsorbs the ions precipitated on the anode plate to reduce the COD in the livestock and poultry wastewater Cr The content.

[0063] S3, add biological filler 32 into the reactor 31. Specifically, the mass of the inoculated anaerobic ammonia oxidation granular sludge 321 is 20.54 g. The anaerobic ammonia oxidation granular sludge 321 comes from a livestock and poultry breeding wastewater treatment system in Guangdong Province. The sludge is enriched with ammonia oxidizing bacteria, anaerobic ammonia oxidizing bacteria and denitrifying bacteria. Biochar 322 is added at one time (the biochar raw material is purchased from Pingdingshan Green Source Co., Ltd., and the main components are wood, coconut shell and coal). The concentration of biochar 322 is 8 g / L and the particle size is 100 μm.

[0064] The constant temperature component 34 is started to keep the reactor 31 at a constant temperature of 35°C, and the COD of the wastewater in the cathode chamber 26 is adjusted. Cr Detection, when COD Cr When the content is ≤300 mg / L, the wastewater in the cathode chamber 26 is introduced into the reactor 31 through the outlet pipe 261, and the dissolved oxygen detector 333 is started. When the dissolved oxygen content in the reactor 31 is lower than 0.2 mg / L, the aeration pump 332 is started to provide aeration. When continuous aeration makes the dissolved oxygen exceed 0.5 mg / L, the aeration pump 332 is turned off to maintain the dissolved oxygen inside the reactor 31 in the range of 0.2-0.5 mg / L.

[0065] S4, livestock and poultry wastewater undergoes biological reaction in the reactor 31, the pH in the reactor 31 is maintained at 7, the hydraulic retention time is 36h, the three-phase separator 35 separates the treated mixture, and the wastewater flows through the overflow outlet of the sedimentation tank 36 at the top of the reactor 31 to the outlet tank 37 for collection, and finally the effluent is stable and continuously discharged up to the standard.

[0066] The working principle of Example 1 of the present application is:

[0067] The livestock and poultry wastewater raw liquid is precipitated in the sedimentation tank 1 to remove the solid waste in the water, and then the wastewater flows from the sedimentation tank 1 into the reaction tank 21. The wastewater can flow in the anode cavity 25 and the cathode cavity 26. The lead dioxide anode and the graphite felt cathode are powered to directly oxidize the wastewater. During the oxidation process, in the oxygen evolution potential interval, that is, the surface of the lead dioxide anode discharges to generate hydroxyl radicals (·OH). The highly active hydroxyl radicals convert the difficult-to-degrade organic matter in the wastewater into low-harm or harmless small molecules, thereby achieving the purpose of wastewater treatment. During the direct oxidation process, the lead ions dissolved from the lead dioxide anode will flow to the adsorption layer and adhere to the adsorption layer 24, so that the lead ions at the outlet meet the emission standards.

[0068] The wastewater after the electrochemical reaction enters the reactor 31, and the dissolved oxygen is controlled in the range of 0.2-0.5 mg / L. The dissolved oxygen is mainly used for the growth and utilization of heterotrophic denitrifying bacteria, allowing the heterotrophic denitrifying bacteria to perform short-range nitrification in a micro-oxygen environment and oxidize ammonia nitrogen into nitrite nitrogen; at the same time, the denitrifying bacteria can use the remaining COD Cr Short-cut denitrification is carried out to reduce nitrate nitrogen to nitrite nitrogen, thereby consuming the remaining COD in the wastewater Cr and nitrate nitrogen; after the dissolved oxygen is consumed by heterotrophic bacteria, it provides a good growth environment for anaerobic ammonia-oxidizing bacteria. Part of the ammonia nitrogen in the wastewater is converted into nitrite nitrogen under the action of ammonia-oxidizing bacteria, which serves as the substrate for the next step of anaerobic ammonia oxidation; anaerobic ammonia-oxidizing bacteria can convert the remaining ammonia nitrogen and nitrite nitrogen into nitrogen gas, and at the same time produce some nitrate nitrogen.

[0069] In addition, biochar can significantly promote the secretion of extracellular polymers. The increased extracellular polymers strengthen the mass transfer drive between the anaerobic ammonium oxidizing bacteria and the functional groups on the surface of biochar, and enhance the extracellular electron transfer capacity of the anaerobic ammonium oxidizing bacteria. Denitrifying bacteria in sludge can utilize the residual COD in wastewater. Cr The nitrate nitrogen is reduced to nitrogen gas, further improving the removal of nitrogen and carbon in the water body, and ultimately achieving denitrification and decarbonization of wastewater.

[0070] By first using electrochemical reaction to remove the refractory organic matter in the wastewater, a reasonable current density is used to seek COD CrThe balance between degradation current efficiency and electrolysis time is achieved to reduce the occurrence of side reactions; moreover, this stage does not pursue the complete mineralization of organic matter, thus greatly saving energy consumption.

[0071] The removal of ammonia nitrogen in wastewater by anaerobic ammonium oxidation reaction saves treatment time and operating costs compared with traditional wastewater treatment systems, thereby improving the treatment efficiency of livestock and poultry wastewater and reducing treatment costs.

[0072] Example 2

[0073] The difference from Example 1 is that the hydraulic retention time in the sedimentation tank 1 is 12 hours, the adsorption layer 24 in the reaction tank 21 uses zeolite with a thickness of 10 cm, the constant voltage in the reaction tank 21 is 3-4V, the amount of sludge inoculated in the reactor 31 is 20g, the temperature of the reactor 31 is 36°C, the pH in the reactor 31 is 8, and the hydraulic retention time in the reactor 31 is 12 hours.

[0074] Example 3

[0075] The difference from Example 1 is that the hydraulic retention time in the sedimentation tank 1 is 48h, the adsorption layer 24 in the reaction tank 21 is diatom mud with a thickness of 30cm, the constant voltage in the reaction tank 21 is 3-4V, the amount of sludge inoculated in the reactor 31 is 21g, the temperature of the reactor 31 is 34°C, the pH in the reactor 31 is 7, and the hydraulic retention time in the reactor 31 is 48h.

[0076] The working principles of Examples 2 and 3 of the present application are consistent with those of Example 1 and will not be repeated here.

[0077] 3. Comparison

[0078] Comparative Example 1

[0079] The difference from Example 1 is that only the same mass of sludge is added to the biological filler in the reactor, and no biochar is added. Through the extraction of EPS (extracellular polymeric substances) of the sludge in the comparative example and the example, and the determination of the corresponding polysaccharides and proteins, it was found that the polysaccharide and protein contents in the EPS of the sludge in Example 1 were 11.18 mg / L and 50.78 mg / L higher than those in Comparative Example 1, respectively. The results show that biochar can significantly promote the secretion of extracellular polymeric substances. The aromatic proteins and humus in the extracellular polymeric substances can serve as electron transfer media to enhance the mass transfer drive between the anaerobic ammonia-oxidizing bacteria and the functional groups on the surface of biochar, thereby strengthening the extracellular electron transfer capacity of the anaerobic ammonia-oxidizing bacteria, thereby enhancing the treatment effect of wastewater.

[0080] 4. Performance testing

[0081] The device and method provided in Examples 1-3 of the present invention have a good treatment effect on wastewater from small-scale standardized pig farms in rural areas. Taking the treatment device of Example 1 as an example, pig farm wastewater was treated, and multiple tests were performed during the process. The average values ​​of the water quality test indicators at each stage before and after the wastewater treatment are shown in Table 1.

[0082] Table 1 Detection index table of livestock and poultry wastewater at each stage

[0083]

[0084] The devices and methods of Example 1 and Comparative Example 1 were used to detect livestock and poultry wastewater from the same source. The differences between Comparative Example 1 and Example 1 are shown in Table 2:

[0085] Table 2 Comparison of detection indicators

[0086]

[0087] Combining Table 1 and Table 2, it can be concluded that the effluent quality of the wastewater treatment device with biochar added is better than that of the wastewater treatment device without biochar added. Therefore, adding biochar can enhance the removal effect of the anaerobic ammonium oxidation system on ammonia nitrogen and other substances in wastewater. This method combines physical precipitation + electrochemistry + anaerobic ammonium oxidation reaction to target high ammonia nitrogen and COD in livestock and poultry wastewater. Cr The water quality characteristics of the wastewater are taken into consideration. The electrochemical device is used to remove the refractory organic matter in the wastewater, and the anaerobic ammonia oxidation system enhanced by biochar is used to remove substances such as ammonia nitrogen in the wastewater. The device and method provided by the present invention are used to treat livestock and poultry wastewater. The treatment index not only meets the water quality index of livestock and poultry breeding wastewater after treatment stipulated in the "Livestock and Poultry Breeding Pollutant Emission Standard (GB18596-2001)", but also specifically reduces the COD in the wastewater. Cr and ammonia nitrogen content, saving treatment time and operating costs compared to traditional wastewater treatment systems, and improving the treatment efficiency of livestock and poultry wastewater. The above are all preferred embodiments of this application, and are not intended to limit the protection scope of this application. Therefore, any equivalent changes made based on the structure, shape, and principle of this application should be covered within the protection scope of this application.

Claims

1. A device for treating high CODCr ammonia nitrogen wastewater by electrochemically enhanced activated carbon coupled anaerobic ammonia oxidation, characterized in that: The invention comprises a sedimentation tank (1), an electrochemical reaction component (2) and an anaerobic ammonium oxidation reaction mechanism (3) which are arranged in sequence, wherein the sedimentation tank (1) is used for solid-liquid separation of livestock and poultry wastewater, the electrochemical reaction component (2) is used for decarbonation pretreatment of livestock and poultry wastewater, and the anaerobic ammonium oxidation reaction mechanism (3) is used for removing ammonia nitrogen from the pretreated livestock and poultry wastewater.

2. The device for treating high CODCr ammonia nitrogen wastewater by electrochemically enhanced activated carbon coupled anaerobic ammonia oxidation according to claim 1, characterized in that: The electrochemical reaction component (2) comprises: A reaction tank (21), the reaction tank (21) being connected to a sedimentation tank (1), an adsorption layer (24) being arranged in the reaction tank (21), the adsorption layer (24) dividing the reaction tank (21) into an anode chamber (25) and a cathode chamber (26), the anode chamber (25) being connected to the sedimentation tank (1) via a water inlet pipe (251), and the cathode chamber (26) being connected to an anaerobic ammonia oxidation reaction mechanism (3) via a water outlet pipe (261); an anode plate (22), wherein the anode plate (22) is disposed in the anode chamber (25); A cathode plate (23), wherein the cathode plate (23) is disposed in the cathode chamber (26), and the anode plate (22) and the cathode plate (23) are connected via an external circuit.

3. The device for treating high CODCr ammonia nitrogen wastewater by electrochemically enhanced activated carbon coupled anaerobic ammonia oxidation according to claim 2, characterized in that: The anaerobic ammonium oxidation reaction mechanism (3) comprises: A reactor (31), wherein the reactor (31) is an upflow reactor (31) and has a water inlet at the bottom, one end of the water outlet pipe (261) away from the cathode chamber (26) is connected to the water inlet, a three-phase separator (35) is provided on the top of the reactor (31), the three-phase separator (35) is connected to a precipitator (36), and the precipitator (36) is externally connected to a water outlet tank (37); A biological filler (32), wherein the biological filler (32) comprises anaerobic ammonium oxidation granular sludge (321) and biochar (322), and the anaerobic ammonium oxidation granular sludge (321) and biochar (322) are filled in the reactor (31) and used for biological treatment of livestock and poultry wastewater; an aeration component (33), the aeration component (33) being arranged in the reactor (31) and used for intermittent aeration; A constant temperature component (34) is arranged on the reactor (31) and is used to control the reactor (31) to maintain a constant temperature.

4. The device for treating high CODCr ammonia nitrogen wastewater by electrochemically enhanced activated carbon coupled anaerobic ammonia oxidation according to claim 3, characterized in that: The aeration assembly (33) comprises an aeration plate (331), an aeration pump (332) and a dissolved oxygen detector (333); the aeration plate (331) is arranged in the reactor (31) and is located above the water inlet; the output end of the aeration pump (332) is connected to the aeration plate (331); the detection element of the dissolved oxygen detector (333) extends into the reactor (31) and is located above the aeration plate (331) and is used to detect the dissolved oxygen content in the reactor (31).

5. The device for treating high CODCr ammonia nitrogen wastewater by electrochemically enhanced activated carbon coupled anaerobic ammonia oxidation according to claim 3, characterized in that: The constant temperature component (34) comprises a water bath interlayer (341), a circulation pool (342), a water delivery pipe (343) and a water return pipe (344); the water bath interlayer (341) is sleeved on the outer wall of the reactor (31); the circulation pool (342) is a constant temperature water bath; two ends of the water delivery pipe (343) are respectively connected to the circulation pool (342) and the water bath interlayer (341) and are located at the bottom of the water bath interlayer (341); and two ends of the water return pipe (344) are respectively connected to the water bath interlayer (341) and the circulation pool (342) and are located at the top of the water bath interlayer (341).

6. The device for treating high CODCr ammonia nitrogen wastewater by electrochemically enhanced activated carbon coupled anaerobic ammonia oxidation according to claim 4, characterized in that: The adsorption layer (24) is selected from at least one of activated carbon, zeolite and diatom mud, and the thickness of the adsorption layer (24) is 10-30 cm; the anode plate (22) is a lead dioxide plate, and the cathode plate (23) is graphite felt.

7. A method for treating high CODCr ammonia nitrogen wastewater by electrochemically enhanced activated carbon coupled anaerobic ammonia oxidation based on the device described in any one of claims 4 to 6, characterized in that: The following steps are involved: S1, introducing livestock and poultry wastewater into the sedimentation tank (1) for sedimentation to remove solid waste in the wastewater; S2, the precipitated wastewater enters the anode chamber (25) through the water inlet pipe (251), the wastewater flows in the reaction tank (21), the power supply of the external circuit is turned on, the anode plate (22) and the cathode plate (23) work to oxidize the organic matter in the wastewater, and the adsorption layer (24) adsorbs the ions precipitated on the anode plate (22) to reduce the CODCr content in the livestock and poultry wastewater; S3, adding biological filler (32) into the reactor (31), starting the constant temperature component (34) to keep the reactor (31) at a constant temperature, detecting the CODCr content of the wastewater in the cathode chamber (26), when the CODCr content is ≤300 mg / L, introducing the wastewater in the cathode chamber (26) into the reactor (31) through the outlet pipe (261), starting the dissolved oxygen detector (333), when the dissolved oxygen content in the reactor (31) is lower than 0.2 mg / L, starting the aeration pump (332) to provide aeration, when the dissolved oxygen exceeds 0.5 mg / L due to continuous aeration, shutting down the aeration pump (332) to maintain the dissolved oxygen in the reactor (31) in the range of 0.2-0.5 mg / L; S4, the livestock and poultry wastewater undergoes a biological reaction in the reactor (31), the three-phase separator (35) separates the treated mixture, and the treated water passes through the sedimentator (36) and enters the water outlet box (37) for collection.

8. The method for treating high CODCr ammonia nitrogen wastewater by electrochemically enhanced activated carbon coupled anaerobic ammonia oxidation according to claim 7, characterized in that: The biochar (322) in S3 is added once, and the concentration of the biochar (322) added is 8 g / L, and the particle size is 100 μm.

9. A method for treating high CODCr ammonia nitrogen wastewater by electrochemically enhanced activated carbon coupled anaerobic ammonia oxidation according to claim 8, characterized in that: The effective volume of the reactor (31) is 2 L, and the amount of the anaerobic ammonium oxidation granular sludge (321) inoculated in the reactor (31) is 20.54±0.75 g.

10. The method for treating high CODCr ammonia nitrogen wastewater by electrochemically enhanced activated carbon coupled anaerobic ammonia oxidation according to claim 9, characterized in that: The working conditions in the reactor (31) are: pH 7-8, temperature 35±1°C, and dissolved oxygen content 0.2-0.5 mg / L.

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