Humic acid extraction system

Abstract

According to the humic acid extraction system provided by the invention, the microbial degradation system can control dissolved oxygen, temperature, organic load and pH value in the nitrification and denitrification system within an operating parameter range so as to culture dominant bacterial communities with strong organic matter degradation capability, and other organic matters except humic acid in a water body are removed through the dominant bacterial communities; in this way, the removal rate of organic matters in the leachate can be increased to 99% or above from traditional 96-97% in a mode of treating the leachate through microorganisms and a material membrane, and the content of other organic matters in humic acid is reduced; moreover, the humic acid extraction system can separate humic acid from percolate and purify pollutants in water only by using a small amount of electric energy, and the extraction process does not need to consume a large amount of chemical agents, so that the effect of separating humic acid by using the traditional chemical agents can be achieved, the usage amount of the agents is reduced, economy and environmental protection are realized, and the method is suitable for industrial production. And social popularization and application are facilitated.

Description

Technical Field

[0001] The present application relates to the technical field of humic acid extraction, and in particular to a humic acid extraction system. Background Art

[0002] Humic acid (HA) is derived from humus substances that are difficult to decompose after the decomposition of animal and plant residues. It is a very complex macromolecular organic matter that is widely present in various natural environments such as water bodies and soil. HA has the functions of passivating heavy metals, improving soil, activating insoluble elements, promoting plant absorption of trace elements, improving the slow release of nutrient elements, stimulating plant development and enhancing plant resistance. It has high value in agriculture, gardening, environmental protection, and medical treatment.

[0003] At present, the main methods for extracting HA include alkali dissolution and acid precipitation, solvent extraction, pyrolysis extraction, resin method, etc. For example, Chinese patent application number CN201010107933.2 discloses a method for extracting humic acid substances from biogas slurry. This method adds a brackish water desalination reverse osmosis membrane unit and a concentrated liquid boiler backwash treatment system to the existing system, solving the problem that the TDS concentration and chloride ion concentration of the DTRO system water production are high and cannot meet the circulating cooling water make-up water standard; however, due to the high suspended solids (SS) in the biogas slurry, generally more than 3000ppm, sand filtration is designed according to the sewage treatment specification, and the sand filtration backwash cycle is generally 8-12 hours. Under the condition of solid suspended matter, the sand filter backwash cycle will be reduced to less than 0.5 hours. Frequent cleaning of the sand filter system not only wastes a lot of tap water, but also greatly reduces the working efficiency. In addition, the filtration accuracy of the sand filter system is limited. A large number of fine particles will still enter the subsequent treatment process and adhere to the resin surface, thereby reducing the resin exchange efficiency. In addition, the extraction process requires the addition of a large amount of desorption agents and resins. Although the resin can be regenerated, its regeneration effect will decrease with the increase of the number of regenerations. At the same time, the resin is easy to break due to friction with water and impurities in the water during use, thereby introducing more solid suspended matter.

[0004] In summary, the existing humic acid extraction system has low operating efficiency, high energy consumption and poor stability; in the process of extracting humic acid from biogas slurry, the biogas slurry cannot be treated to the discharge standard or reuse standard and still needs further treatment, which is neither economical nor environmentally friendly. Utility Model Content

[0005] The purpose of this application is to solve at least one of the above-mentioned technical defects, especially the low operating efficiency, high energy consumption and poor stability of the humic acid extraction system in the prior art; in the process of extracting humic acid from the biogas slurry, the biogas slurry cannot be treated to the discharge standard or reuse standard and still needs further treatment, which is neither economical nor environmentally friendly.

[0006] The present application provides a humic acid extraction system, which includes a nitrification and denitrification system, an ultrafiltration membrane, a material membrane, a high-pressure membrane, and a microbial degradation system;

[0007] The nitrification and denitrification system is used to transport the wastewater containing humic acid obtained after two-stage nitrification and denitrification of the leachate to the ultrafiltration membrane;

[0008] The ultrafiltration membrane is used to separate the activated sludge in the wastewater containing humic acid and transport the remaining wastewater to the material membrane;

[0009] The material membrane is used to selectively intercept the remaining wastewater and transfer the intercepted humic acid to the high-pressure membrane;

[0010] The high-pressure membrane is used to concentrate the intercepted humic acid, store the concentrated humic acid, and transport the remaining high-pressure membrane clear liquid to the nitrification and denitrification system;

[0011] The microbial degradation system is used to control the dissolved oxygen, temperature, organic load and pH value in the nitrification and denitrification system within the operating parameter range to cultivate a dominant bacterial community with strong organic matter degradation ability, and remove other organic matter in the water body except humic acid through the dominant bacterial community.

[0012] Optionally, the nitrification and denitrification system comprises a primary denitrification tank, a primary nitrification tank, a secondary denitrification tank and a secondary nitrification tank which are connected in sequence.

[0013] Optionally, activated sludge is added to the primary denitrification tank and the secondary denitrification tank;

[0014] Two different types of autotrophic aerobic bacteria are added into the primary nitrification tank and the secondary nitrification tank.

[0015] Optionally, the connection port between the primary denitrification tank and the primary nitrification tank is arranged at the upper part;

[0016] The connection port between the primary nitrification tank and the secondary denitrification tank is arranged at the lower part;

[0017] The connection port between the secondary denitrification tank and the secondary nitrification tank is arranged at the upper part.

[0018] Optionally, the output end of the secondary nitrification tank is also connected to the input end of the first denitrification tank through a circulation pump.

[0019] Optionally, the reflux ratio at the output end of the secondary nitrification tank is controlled to be 12:1 by the circulation pump.

[0020] Optionally, the output end of the secondary nitrification tank transports the wastewater containing humic acid to the ultrafiltration membrane through a membrane transport pump;

[0021] The ultrafiltration membrane returns part of the separated activated sludge to the first denitrification tank for continued use, and discharges the remaining activated sludge to the sludge storage tank.

[0022] Optionally, the material membrane discharges the intercepted humic acid from the concentrated water channel and transports it to the high-pressure membrane through a high-pressure pump.

[0023] Optionally, the microbial degradation system includes an online pH meter, an online temperature and dissolved oxygen meter, a PLC controller and a monitoring computer;

[0024] The input end of the monitoring computer is respectively connected to the online pH meter, the online temperature and dissolved oxygen meter and the ultrafiltration membrane, and the output end is connected to the PLC controller;

[0025] The online pH meter is used to monitor the pH values ​​of the primary denitrification tank and the secondary denitrification tank, and send the first monitoring result to the monitoring computer;

[0026] The online temperature and dissolved oxygen meter is used to monitor the temperature and dissolved oxygen of the primary nitrification tank and the secondary nitrification tank, and send the second monitoring result to the monitoring computer;

[0027] The monitoring computer is used to control the PLC controller to perform relevant operations based on the first monitoring result, the second monitoring result and the amount of activated sludge reflowing in the ultrafiltration membrane, so that the dissolved oxygen, temperature, organic load and pH value in the nitrification and denitrification system are controlled within the operating parameter range.

[0028] The present application also provides a humic acid extraction method, which is applied to the humic acid extraction system described in any one of the above embodiments, and the method comprises:

[0029] The leachate is sent to a nitrification and denitrification system, and other organic matter except humic acid in the water body is removed by the dominant bacteria in the nitrification and denitrification system to obtain wastewater containing humic acid; wherein the dominant bacteria are cultivated by controlling the dissolved oxygen, temperature, organic load and pH value in the nitrification and denitrification system within the operating parameter range through a microbial degradation system;

[0030] The wastewater containing humic acid is sequentially separated and concentrated through an ultrafiltration membrane, a material membrane and a high-pressure membrane to obtain humic acid.

[0031] It can be seen from the above technical solutions that the embodiments of the present application have the following advantages:

[0032] The present application provides a humic acid extraction system and a humic acid extraction method, which include a nitrification and denitrification system, an ultrafiltration membrane, a material membrane, a high-pressure membrane and a microbial degradation system; wherein the nitrification and denitrification system can transport the wastewater containing humic acid obtained after two-stage nitrification and denitrification of the leachate to the ultrafiltration membrane, so that the ultrafiltration membrane can separate the activated sludge in the wastewater containing humic acid, and transport the remaining wastewater to the material membrane; the material membrane can selectively intercept the remaining wastewater, and transfer the intercepted humic acid to the high-pressure membrane, so that the high-pressure membrane can concentrate the intercepted humic acid, and store the humic acid obtained after concentration, and transport the remaining high-pressure membrane clear liquid to the nitrification and denitrification system, so as to recover the small molecular organic matter and inorganic salts and other pollutants in the high-pressure membrane clear liquid into the nitrification and denitrification system for further treatment; further, the microbial degradation system of the present application can The dissolved oxygen, temperature, organic load and pH value in the system are controlled within the operating parameter range to cultivate a dominant bacterial community with strong organic matter degradation ability, and remove other organic matter in the water body except humic acid through the dominant bacterial community, so that the organic matter removal rate in the leachate can be increased from the traditional 96-97% to more than 99% through the method of treating the leachate with microorganisms + material membranes, and the content of other organic matter in the humic acid can be reduced; and the humic acid extraction system of the present application only requires a small amount of electrical energy to separate humic acid from the leachate and purify pollutants in the water at the same time, and the extraction process does not require the consumption of a large amount of chemical agents, and can achieve the effect of traditional chemical agents to separate humic acid, thereby reducing the use of agents and achieving economic and environmental protection; in addition, the present application can also be applied to industrial wastewater with complex water quality and high pollutant content, as well as wastewater treatment in other fields, which is conducive to social promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0034] Figure 1 A system architecture diagram of a humic acid extraction system provided in an embodiment of the present application;

[0035] Figure 2 This is a process flow chart of the humic acid extraction system provided in an embodiment of the present application.

[0036] In the above picture: 1. Primary denitrification tank; 2. Primary nitrification tank; 3. Secondary denitrification tank; 4. Secondary nitrification tank; 5. Ultrafiltration membrane; 6. Material membrane; 7. High-pressure membrane; 8. Standard water; 9. Humic acid storage tank; 10. Sludge storage tank; 11. Circulation pump; 12. Membrane transfer pump; 13. High-pressure pump; 14 Online pH meter; 15. Online temperature and dissolved oxygen meter; 16. Online pH meter; 17. Online temperature and dissolved oxygen meter; 18. PLC controller; 19. Monitoring computer. DETAILED DESCRIPTION

[0037] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0038] In one embodiment, Figure 1 As shown, Figure 1 A system architecture diagram of a humic acid extraction system provided in an embodiment of the present application; the present application provides a humic acid extraction system, which may include a nitrification and denitrification system, an ultrafiltration membrane 5, a material membrane 6, a high-pressure membrane 7, and a microbial degradation system.

[0039] The nitrification and denitrification system is used to transport the wastewater containing humic acid obtained after the leachate is subjected to two-stage nitrification and denitrification to the ultrafiltration membrane 5 .

[0040] The ultrafiltration membrane 5 is used to separate the activated sludge in the wastewater containing humic acid, and to transport the remaining wastewater to the material membrane 6 .

[0041] The material membrane 6 is used to selectively intercept the remaining wastewater and transfer the intercepted humic acid to the high-pressure membrane 7 .

[0042] The high-pressure membrane 7 is used to concentrate the intercepted humic acid and store the concentrated humic acid, and the remaining high-pressure membrane clear liquid is transported to the nitrification and denitrification system.

[0043] The microbial degradation system is used to control the dissolved oxygen, temperature, organic load and pH value in the nitrification and denitrification system within the operating parameter range to cultivate a dominant bacterial community with strong organic matter degradation ability, and remove other organic matter in the water body except humic acid through the dominant bacterial community.

[0044] In this embodiment, Figure 1As shown, the humic acid extraction system of the present application may include a nitrification and denitrification system, an ultrafiltration membrane 5, a material membrane 6, a high-pressure membrane 7 and a microbial degradation system, wherein the nitrification and denitrification system, the ultrafiltration membrane 5, the material membrane 6 and the high-pressure membrane 7 are connected in sequence, and the microbial degradation system can control the dissolved oxygen, temperature, organic load and pH value in the nitrification and denitrification system within the operating parameter range to cultivate a dominant bacterial community with a strong ability to degrade organic matter. In this way, after receiving the leachate, the nitrification and denitrification system can remove other organic matter in the water body except humic acid through the dominant bacterial community, and the wastewater containing humic acid is separated and concentrated through the ultrafiltration membrane 5, the material membrane 6 and the high-pressure membrane 7 in sequence to obtain the final humic acid.

[0045] Specifically, since different microorganisms (microorganisms) mainly rely on dissolved oxygen, temperature, organic load and pH value for survival, dissolved oxygen refers to molecular oxygen dissolved in water, and organic load refers to the amount of organic pollutants accepted by a unit volume of sewage treatment reactor per unit time. Therefore, when the present application adopts a nitrification and denitrification system to nitrify and denitrify the leachate, the dissolved oxygen, temperature, organic load and pH value in the nitrification and denitrification system can be controlled within the operating parameter range through a microbial degradation system to cultivate a dominant microorganism with strong organic matter degradation ability, such as activated sludge, autotrophic aerobic bacteria, etc.; and the nitrification and denitrification system of the present application can be designed with a two-stage nitrification tank and a two-stage denitrification tank, so that the leachate can be nitrified and denitrified at two stages through the two-stage nitrification tank and the two-stage denitrification tank, and the operating cost of the system can be reduced while degrading organic matter. In addition, when the present application controls the dissolved oxygen, temperature, organic load and pH value in the nitrification and denitrification system through the microbial degradation system, the dissolved oxygen, temperature and pH value in the nitrification and denitrification system can be monitored by relevant instruments, and the organic load in the nitrification and denitrification system can also be controlled by monitoring the amount of activated sludge separated by the ultrafiltration membrane 5.

[0046] Furthermore, in the present application, most of the organic matter in the leachate after degradation by the nitrification and denitrification system is basically consumed, and most of the remaining organic matter is large-molecule refractory humic acid (HA). At this time, the wastewater containing humic acid can be transported to the ultrafiltration membrane 5 to separate the wastewater into mud and water through the mud-water separation function of the ultrafiltration membrane 5. The separated activated sludge can be partially returned to the nitrification and denitrification system for continued use, and the remaining wastewater containing humic acid can be transported to the material membrane 6, so that the material membrane 6 can selectively intercept the remaining wastewater using its selective interception principle, and transfer the intercepted humic acid to the high-pressure membrane 7. The qualified water 8 purified by the material membrane 6 can also be used for industrial reuse or greening; after the high-pressure membrane 7 receives the intercepted humic acid, it can be further concentrated, and the humic acid obtained after concentration can be discharged to the humic acid storage tank 9 for storage. In addition, the present application can also transport the remaining high-pressure membrane clear liquid to the nitrification and denitrification system for circulation treatment, so as to treat pollutants such as small molecular organic matter and inorganic salts again.

[0047] In the above embodiment, the system includes a nitrification and denitrification system, an ultrafiltration membrane 5, a material membrane 6, a high-pressure membrane 7 and a microbial degradation system; wherein the nitrification and denitrification system can transport the wastewater containing humic acid obtained after two-stage nitrification and denitrification of the leachate to the ultrafiltration membrane 5, so that the ultrafiltration membrane 5 can separate the activated sludge in the wastewater containing humic acid, and transport the remaining wastewater to the material membrane 6; the material membrane 6 can selectively intercept the remaining wastewater, and transfer the intercepted humic acid to the high-pressure membrane 7, so that the high-pressure membrane 7 can concentrate the intercepted humic acid, and store the humic acid obtained after concentration, and transport the remaining high-pressure membrane clear liquid to the nitrification and denitrification system, so as to recover the small molecular organic matter and inorganic salts and other pollutants in the high-pressure membrane clear liquid into the nitrification and denitrification system for further treatment; further, the microbial degradation system of the present application can The dissolved oxygen, temperature, organic load and pH value are controlled within the operating parameter range to cultivate a dominant bacterial community with strong organic matter degradation ability, and remove other organic matter in the water body except humic acid through the dominant bacterial community, so that the organic matter removal rate in the leachate can be increased from the traditional 96-97% to more than 99% through the microorganism + material membrane 6 to treat the leachate, and the content of other organic matter in the humic acid can be reduced; and the humic acid extraction system of the present application only requires a small amount of electrical energy to separate humic acid from the leachate and purify pollutants in the water at the same time, and the extraction process does not require the consumption of a large amount of chemical agents, and can achieve the effect of traditional chemical agents to separate humic acid, thereby reducing the use of agents and achieving economic and environmental protection; in addition, the present application can also be applied to industrial wastewater with complex water quality and high pollutant content, as well as wastewater treatment in other fields, which is conducive to social promotion and application.

[0048] In one embodiment, Figure 2 As shown, Figure 2 A process flow chart of a humic acid extraction system provided in an embodiment of the present application; the nitrification and denitrification system comprises a primary denitrification tank 1, a primary nitrification tank 2, a secondary denitrification tank 3 and a secondary nitrification tank 4 which are connected in sequence.

[0049] In this embodiment, Figure 2 As shown, the nitrification and denitrification system of the present application may include a primary denitrification tank 1, a primary nitrification tank 2, a secondary denitrification tank 3 and a secondary nitrification tank 4 connected in sequence. In the primary denitrification tank 1 and the secondary denitrification tank 3, nitrate or nitrite is used as an electron acceptor by denitrifying bacteria under anaerobic or anoxic conditions, and these bacteria can use the organic carbon source in the sewage as an electron donor, and reduce the nitrate to nitrogen (N2) through a series of biochemical reactions and escape from the water surface, thereby completing the removal of nitrogen and organic matter.

[0050] Furthermore, the primary nitrification tank 2 and the secondary nitrification tank 4 play a core role in biological denitrification in the sewage treatment process, mainly used for the conversion of ammonia nitrogen (NH3-N) into nitrite nitrogen (NO2--N) and nitrate nitrogen (NO3--N). Under aerobic conditions, microorganisms consume oxygen and decompose organic matter in sewage, ultimately generating carbon dioxide, water and microbial cell biomass.

[0051] In the present application, the leachate after denitrification and nitrification flows from the primary denitrification tank 1 to the primary nitrification tank 2, the secondary denitrification tank 3 and the secondary nitrification tank 4 under the action of gravity, further removing nitrates and organic matter in the water body, thereby achieving the purpose of biogas slurry purification.

[0052] In one embodiment, activated sludge is added into the primary denitrification tank 1 and the secondary denitrification tank 3 .

[0053] Two different types of autotrophic aerobic bacteria are added into the primary nitrification tank 2 and the secondary nitrification tank 4 .

[0054] In this embodiment, activated sludge can be added to the primary denitrification tank 1 and the secondary denitrification tank 3. The activated sludge (bacteria) in the tank can not only be flocculated, adsorbed and biotransformed by microorganisms, but also effectively remove suspended solids in the water body in the subsequent mud-water separation process of the ultrafiltration membrane 5.

[0055] Furthermore, since nitrification is an aerobic process, the process can be completed in two steps by two different types of autotrophic aerobic bacteria (nitrite bacteria and nitrifying bacteria):

[0056] Step 1 (nitrosation): Ammonia oxidizing bacteria (AOB) convert ammonia nitrogen into nitrite nitrogen (NH3→NO2-);

[0057] Step 2 (nitrification): Nitrite oxidizing bacteria (NOB) continue to convert nitrite nitrogen into nitrate nitrogen (NO2-→NO3-).

[0058] In the above nitrification process under aerobic conditions, microorganisms consume oxygen and decompose organic matter in sewage, ultimately generating carbon dioxide, water and microbial cell biomass.

[0059] In one embodiment, the connection port between the primary denitrification tank 1 and the primary nitrification tank 2 is arranged at the upper part.

[0060] The connection port of the primary nitrification tank 2 and the secondary denitrification tank 3 is arranged at the lower part.

[0061] The connection port of the secondary denitrification tank 3 and the secondary nitrification tank 4 is arranged at the upper part.

[0062] In this embodiment, Figure 2 As shown, after the present application sets up a primary denitrification tank 1, a primary nitrification tank 2, a secondary denitrification tank 3 and a secondary nitrification tank 4, the present application can also set the connection port of the primary denitrification tank 1 and the primary nitrification tank 2 at the upper part, the connection port of the primary nitrification tank 2 and the secondary denitrification tank 3 at the lower part, and the connection port of the secondary denitrification tank 3 and the secondary nitrification tank 4 at the upper part. After the biogas slurry enters the nitrification tank or the denitrification tank, the liquid level will rise and flow to other tanks through each connection port under the action of gravity. This can prevent the sewage from short-circuiting and avoid sludge precipitation, and can also make bacteria fully contact with pollutants, thereby effectively improving the sewage treatment effect and treatment efficiency.

[0063] In one embodiment, the output end of the secondary nitrification tank 4 is also connected to the input end of the first denitrification tank through a circulation pump 11 .

[0064] In this embodiment, in order to prevent the activated sludge from settling in the pool and improve the pollutant removal efficiency, Figure 2 As shown, the present application can also connect the output end of the secondary nitrification tank 4 to the input end of the first denitrification tank through a circulation pump 11, so that the sludge at the bottom of the tank will not be deposited and the contact probability between the bacterial flora and pollutants will be increased, so as to achieve the effect of cultivating dominant bacterial flora and efficiently removing pollutants.

[0065] In one embodiment, the reflux ratio at the output end of the secondary nitrification tank 4 is controlled to be 12:1 by the circulation pump 11.

[0066] In this embodiment, in the process of returning part of the wastewater in the secondary nitrification tank 4 to the primary denitrification tank 1 through the circulation pump 11, the circulation pump 11 can also be used to control the reflux ratio of the output end of the secondary nitrification tank 4 to 12:1, so that the sludge at the bottom of the tank is not deposited, the contact probability between the bacterial flora and the pollutants is increased, and sufficient wastewater input is ensured in the ultrafiltration membrane 5.

[0067] It is understandable that the reflux ratio of the present application is determined based on experimental and empirical data. Specifically, the pollutant removal effect can be determined based on the water quality test results, and without destroying the bacterial mass (microscope detection), the circulation volume is adjusted by the frequency converter to increase the contact probability between microorganisms and pollutants, while preventing the sludge from settling. In addition, under normal circumstances, the circulation pump 11 of the present application is in a normally open state, so that the contact probability between microorganisms and pollutants in the nitrification and denitrification system can be maintained, and the activated sludge can be prevented from settling.

[0068] In one embodiment, the output end of the secondary nitrification tank 4 transports the wastewater containing humic acid to the ultrafiltration membrane 5 via a membrane transport pump 12 .

[0069] The ultrafiltration membrane 5 returns part of the separated activated sludge to the first denitrification tank for continued use, and discharges the remaining activated sludge to the sludge storage tank 10.

[0070] In this embodiment, Figure 2 As shown, the present application can install a membrane delivery pump 12 at the output end of the secondary nitrification tank 4, so that the wastewater containing humic acid in the secondary nitrification tank 4 can be delivered to the ultrafiltration membrane 5 through the membrane delivery pump 12, and after the ultrafiltration membrane 5 separates the activated sludge, the remaining wastewater can be delivered to the material membrane 6.

[0071] Furthermore, the ultrafiltration membrane 5 of the present application can also return part of the separated activated sludge to the first denitrification tank for continued use, and discharge the remaining activated sludge to the sludge storage tank 10, which can avoid excessive loss of bacterial mass and affect the sewage treatment effect, and can also discharge excess sludge from the system. In addition, the activated sludge in the sludge storage tank 10 can also be treated by incineration, landfill or organic fertilizer production, which can be treated according to actual conditions and is not limited here.

[0072] In one embodiment, the material membrane 6 discharges the retained humic acid from the concentrated water channel and transports it to the high-pressure membrane 7 through the high-pressure pump 13 .

[0073] In this embodiment, the material membrane 6 can not only intercept humic acid from the remaining wastewater through its selective interception principle, and discharge the intercepted humic acid from the concentrated water channel and transport it to the high-pressure membrane 7 through the high-pressure pump 13, but also can reuse the purified qualified water 8 for industrial use or greening use, so as to achieve economic and environmental protection effects.

[0074] In one embodiment, the microbial degradation system includes online pH meters 14 and 16 , online temperature and dissolved oxygen meters 15 and 17 , a PLC controller 18 and a monitoring computer 19 .

[0075] The input end of the monitoring computer 19 is respectively connected to the online pH meters 14 , 16 , the online temperature and dissolved oxygen meters 15 , 17 and the ultrafiltration membrane 5 , and the output end is connected to the PLC controller 18 .

[0076] The online pH meters 14 and 16 are used to monitor the pH values ​​of the primary denitrification tank 1 and the secondary denitrification tank 3 , and send the first monitoring results to the monitoring computer 19 .

[0077] The online temperature and dissolved oxygen meters 15 and 17 are used to monitor the temperature and dissolved oxygen of the primary nitrification tank 2 and the secondary nitrification tank 4 , and send the second monitoring result to the monitoring computer 19 .

[0078] The monitoring computer 19 is used to control the PLC controller 18 to perform relevant operations based on the first monitoring result, the second monitoring result and the amount of activated sludge reflowing in the ultrafiltration membrane 5, so that the dissolved oxygen, temperature, organic load and pH value in the nitrification and denitrification system are controlled within the operating parameter range.

[0079] In this embodiment, the microbial degradation system can control the dissolved oxygen, temperature, organic load and pH value in the nitrification and denitrification system within the operating parameter range to cultivate a dominant bacterial community with strong organic matter degradation ability. In this way, after receiving the leachate, the nitrification and denitrification system can remove other organic matter in the water body except humic acid through the dominant bacterial community, and separate and concentrate the wastewater containing humic acid through the ultrafiltration membrane 5, the material membrane 6 and the high-pressure membrane 7 in turn to obtain the final humic acid.

[0080] Specifically, the microbial degradation system of the present application may include online pH meters 14, 16, online temperature and dissolved oxygen meters 15, 17, a PLC controller 18 and a monitoring computer 19, wherein the online pH meters 14, 16 may be installed in the primary denitrification tank 1 and the secondary denitrification tank 3, respectively, so that the pH values ​​of the primary denitrification tank 1 and the secondary denitrification tank 3 may be monitored, and the first monitoring result may be sent to the monitoring computer 19; the online temperature and dissolved oxygen meters 15, 17 may be installed in the primary nitrification tank 2 and the secondary nitrification tank 4, respectively, and after monitoring the temperature and dissolved oxygen of the primary nitrification tank 2 and the secondary nitrification tank 4, the second monitoring result may be sent to the monitoring computer 19, and the monitoring computer 19 may also be connected to the ultrafiltration membrane 5, so as to obtain the activity of the reflux in the ultrafiltration membrane 5. The amount of activated sludge can be compared with the preset operating parameter range. If it is not within the operating parameter range, the monitoring computer 19 will remind the operator, or automatically add acid or alkali through the PLC controller 18, and the second monitoring result can be compared with the preset operating parameter range. If it is not within the operating parameter range, the monitoring computer 19 will remind the operator, or automatically control the fan blowing frequency or the cooling tower fan frequency through the PLC controller 18 to achieve temperature control or dissolved oxygen control process; further, the monitoring computer 19 can also control the organic load of the primary denitrification tank 1 according to the amount of activated sludge returned from the ultrafiltration membrane 5, and control the reflux ratio through the circulating pump 11, so that most of the remaining organic matter in the sewage is humic acid that is difficult to be degraded by microorganisms.

[0081] For example, the present application can control the pH value in the primary denitrification tank 1 and the secondary denitrification tank 3 to be 7.0-7.2 through the online pH meters 14 and 16, control the temperature in the primary nitrification tank 2 and the secondary nitrification tank 4 to be 30-33°C and the dissolved oxygen to be 1.0-1.5ppm through the online temperature and dissolved oxygen meters 15 and 17, control the organic load in the primary denitrification tank 1 to be 0.2-0.4kgBOD5 / (kgMLVSS·d) through the sludge return of the ultrafiltration membrane 5, and control the reflux ratio to be 12:1 through the circulation pump 11, so as to cultivate dominant bacteria with strong organic matter degradation ability (such as Bacillus, Flavobacterium, etc.), so that most of the remaining organic matter in the sewage is humic acid that is difficult to be degraded by microorganisms.

[0082] Finally, it should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0083] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The various embodiments can be combined as needed, and the same or similar parts can refer to each other.

[0084] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A humic acid extraction system, characterized in that: The system includes a nitrification and denitrification system, an ultrafiltration membrane, a material membrane, a high-pressure membrane and a microbial degradation system; The nitrification and denitrification system is used to transport the wastewater containing humic acid obtained after two-stage nitrification and denitrification of the leachate to the ultrafiltration membrane; The ultrafiltration membrane is used to separate the activated sludge in the wastewater containing humic acid and transport the remaining wastewater to the material membrane; The material membrane is used to selectively intercept the remaining wastewater and transfer the intercepted humic acid to the high-pressure membrane; The high-pressure membrane is used to concentrate the intercepted humic acid, store the concentrated humic acid, and transport the remaining high-pressure membrane clear liquid to the nitrification and denitrification system; The microbial degradation system is used to control the dissolved oxygen, temperature, organic load and pH value in the nitrification and denitrification system within the operating parameter range to cultivate a dominant bacterial community with strong organic matter degradation ability, and remove other organic matter in the water body except humic acid through the dominant bacterial community.

2. The humic acid extraction system according to claim 1, characterized in that: The nitrification and denitrification system comprises a primary denitrification tank, a primary nitrification tank, a secondary denitrification tank and a secondary nitrification tank which are connected in sequence.

3. The humic acid extraction system according to claim 2, characterized in that: Activated sludge is added into the primary denitrification tank and the secondary denitrification tank; Two different types of autotrophic aerobic bacteria are added into the primary nitrification tank and the secondary nitrification tank.

4. The humic acid extraction system according to claim 2, characterized in that: The connection port between the primary denitrification tank and the primary nitrification tank is arranged at the upper part; The connection port between the primary nitrification tank and the secondary denitrification tank is arranged at the lower part; The connection port between the secondary denitrification tank and the secondary nitrification tank is arranged at the upper part.

5. The humic acid extraction system according to claim 2, characterized in that: The output end of the secondary nitrification tank is also connected to the input end of the primary denitrification tank through a circulation pump.

6. The humic acid extraction system according to claim 5, characterized in that: The circulation pump controls the reflux ratio at the output end of the secondary nitrification tank to be 12:

1.

7. The humic acid extraction system according to claim 2, characterized in that: The output end of the secondary nitrification tank transports the wastewater containing humic acid to the ultrafiltration membrane through a membrane transport pump; The ultrafiltration membrane returns part of the separated activated sludge to the primary denitrification tank for continued use, and discharges the remaining activated sludge to the sludge storage tank.

8. The humic acid extraction system according to claim 1, characterized in that: The material membrane discharges the intercepted humic acid from the concentrated water channel and transports it to the high-pressure membrane through a high-pressure pump.

9. The humic acid extraction system according to claim 7, characterized in that: The microbial degradation system includes an online pH meter, an online temperature and dissolved oxygen meter, a PLC controller and a monitoring computer; The input end of the monitoring computer is respectively connected to the online pH meter, the online temperature and dissolved oxygen meter and the ultrafiltration membrane, and the output end is connected to the PLC controller; The online pH meter is used to monitor the pH values ​​of the primary denitrification tank and the secondary denitrification tank, and send the first monitoring result to the monitoring computer; The online temperature and dissolved oxygen meter is used to monitor the temperature and dissolved oxygen of the primary nitrification tank and the secondary nitrification tank, and send the second monitoring result to the monitoring computer; The monitoring computer is used to control the PLC controller to perform relevant operations based on the first monitoring result, the second monitoring result and the amount of activated sludge reflowing in the ultrafiltration membrane, so that the dissolved oxygen, temperature, organic load and pH value in the nitrification and denitrification system are controlled within the operating parameter range.

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