Method and system for advanced treatment of coking wastewater

Abstract

The present application relates to a kind of coking wastewater advanced treatment method and system, method includes: the water quality characteristics of coking wastewater are pre-configured with modified polyurethane suspended filler, modified anode electrode and modified fly ash filler;Coking wastewater is sent into biochemical pool and carries out biochemical reaction, and modified polyurethane suspended filler is placed in biochemical pool;The effluent of biochemical pool is sent into electro-catalytic oxidation device and carries out electrolysis reaction, and electro-catalytic oxidation device uses modified anode electrode as anode electrode, and uses graphite electrode as cathode electrode;The effluent of electro-catalytic oxidation device is sent into filler adsorption tower and carries out adsorption treatment, and modified fly ash filler is placed in filler adsorption tower.The present application is pre-configured with modified polyurethane suspended filler, modified anode electrode and modified fly ash filler for coking wastewater advanced treatment for the water quality characteristics of coking wastewater, can economically and efficiently reduce the content of TOC, total fluorinated alkyl compound and total cyanide in coking wastewater.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of water treatment, and particularly relates to a coking wastewater advanced treatment method and system. BACKGROUND

[0002] Coking is a typical "two high one resource" industry with high energy consumption, high pollution and resource. A large amount of coking wastewater is discharged in the coking process. The coking wastewater is formed in the process of high-temperature dry distillation of coal and gas purification and chemical product refining, and contains cyanide, perfluoroalkyl compounds, polycyclic aromatic hydrocarbons and other difficult-to-degrade pollutants, and has the characteristics of high pollutant concentration, high color, high toxicity and stable composition.

[0003] The coking wastewater treatment at home and abroad usually adopts a biological method, including A / O method, A2 / O method, A2 / O2 method and the like. However, the toxic pollutants such as cyanide, perfluoroalkyl compounds and polycyclic aromatic hydrocarbons in the wastewater can inhibit or even poison the microorganisms in the biological treatment, affect the normal operation of the biological reaction, and cause unstable effluent indexes. In addition, the residual cyanide and difficult-to-degrade organic matter in the coking wastewater deep reuse and zero discharge process are concentrated by multiple stages of membranes, and the concentration is increased, which can easily cause membrane pollution and affect the operation stability of the zero discharge system.

[0004] Therefore, it is necessary to study a process for efficiently treating total organic carbon (TOC), perfluoroalkyl compounds and total cyanide in coking wastewater. SUMMARY

[0005] The present application aims to provide a coking wastewater advanced treatment method and system to solve the problem that the biological method treatment is affected by the difficult-to-degrade pollutants such as perfluoroalkyl compounds and total cyanide in the existing coking wastewater.

[0006] In order to achieve the above-mentioned purpose, the present application provides a coking wastewater advanced treatment method, comprising:

[0007] The modified polyurethane suspended filler, the modified anode electrode and the modified fly ash filler are pre-configured according to the water quality characteristics of the coking wastewater;

[0008] The coking wastewater is sent into a biochemical tank for biochemical reaction, and the modified polyurethane suspended filler is placed in the biochemical tank;

[0009] The effluent of the biochemical tank is sent into an electro-catalytic oxidation device for electrolysis reaction, and the electro-catalytic oxidation device uses the modified anode electrode as an anode electrode and a graphite electrode as a cathode electrode;

[0010] The effluent of the electro-catalytic oxidation device is sent into a filler adsorption tower for adsorption treatment, and the modified fly ash filler is placed in the filler adsorption tower.

[0011] Optionally, the biochemical tank comprises an anoxic tank and an aerobic tank connected in sequence, the modified polyurethane suspended filler is filled in the anoxic tank at a filling amount of 23-29%, and the modified polyurethane suspended filler is filled in the aerobic tank at a filling amount of 37-41%.

[0012] Optionally, the coking wastewater has a residence time of 23-34 h in the anoxic tank, a residence time of 41-59 h in the aerobic tank, a residence time of 21-33 min in the electro-catalytic oxidation device, and a residence time of 37-42 min in the filler adsorption tower.

[0013] Optionally, the modified polyurethane suspended filler is prepared from ordinary polyurethane filler, water-soluble polyurethane solution, polyhydroxybutyric acid valeric acid ester, and protease, the modified anode electrode is prepared from titanium plate, sulfuric acid solution, industrial petroleum ether, citric acid solution, lead nitrate, ferric chloride, and ruthenium chloride, and the modified fly ash filler is prepared from fly ash, alkaline steel slag, sulfuric acid solution, and ferric sulfate solution.

[0014] Optionally, the preparation method of the modified polyurethane suspended filler comprises:

[0015] Preparation of water-soluble polyurethane solution with a mass percentage of 94-98%;

[0016] Add 35-67 mg of polyhydroxybutyric acid valeric acid ester and 0.5-1.3 mg of protease to each liter of water-soluble polyurethane solution to obtain water-soluble polyurethane mixed solution, and ultrasonic for 30-45 min for sufficient mixing;

[0017] Soak the ordinary polyurethane filler in the water-soluble polyurethane mixed solution for 12-16 h, and then drain after taking out;

[0018] Put the polyurethane filler obtained after draining into a blast drying oven, control the temperature of the blast drying oven at 67-72℃, and keep the temperature constant for 310-420 min, and then cool to prepare the modified polyurethane suspended filler.

[0019] Optionally, the preparation method of the modified anode electrode comprises:

[0020] Soak the titanium plate in a sulfuric acid solution with a mass percentage of 25-29% for 40-45 min, then soak the titanium plate in industrial petroleum ether for 20-25 min, take out and place in a muffle furnace at 105℃ for 85-95 min, and then naturally cool down after taking out;

[0021] A 1.9-3.8 mol / L citric acid solution is prepared, 45-56 mg of lead nitrate, 23-34 mg of ferric trichloride and 0.6-1.7 mg of ruthenium chloride are added to each liter of the citric acid solution, and the mixture is ultrasonically treated for 20-35 min to form a citric acid mixed solution;

[0022] The titanium plate after natural cooling is immersed in the citric acid mixed solution at a temperature of 45-56℃ for 155-310 min, and then is placed in the muffle furnace, which is first heated to 211-245℃ at a rate of 2-4℃ / min and maintained for 35-46 min, and then heated to 556-623℃ at a rate of 4-5℃ / min and maintained for 45-55 min, and then cooled to room temperature to prepare the modified anode electrode.

[0023] Optionally, the distance between the anode electrode and the cathode electrode is 2.5 cm, and the current density is 3.3-3.9 A / m 2 .

[0024] Optionally, the preparation method of the modified fly ash filler comprises:

[0025] The fly ash with a specific surface area of 8.1-13 m 2 / g and the basic steel slag with a specific surface area of 0.2-0.4 m 2 / g and a particle size of 1-2 mm are mixed in a volume ratio of 16-21:1, and then are mechanically stirred for 23-27 min to form a fly ash-steel slag mixture;

[0026] A 4-7% sulfuric acid solution by mass percentage is prepared, and the fly ash-steel slag mixture is immersed in the sulfuric acid solution at 55-62℃ for 92-236 min, and then is drained and placed in a muffle furnace at 105℃ for 89-125 min, and then is naturally cooled;

[0027] A 567-629 mg / L iron sulfate solution is prepared, and 7-9 g of the fly ash-steel slag mixture is placed in each liter of the iron sulfate solution;

[0028] The obtained mixed solution is irradiated under a microwave power of 600 W for 15-20 min, and is stirred for 55-63 min, and then is filtered to prepare the modified fly ash filler.

[0029] Optionally, the height to diameter ratio of the filler adsorption tower is 6-1, and the modified fly ash filler accounts for 76-82% of the entire filler adsorption tower by volume.

[0030] Based on the same inventive concept, the present invention also provides a coking wastewater deep treatment system for realizing the coking wastewater deep treatment method as described above, including a dosing unit and a biochemical tank, an electrocatalytic oxidation device and a packed adsorption tower connected in sequence.

[0031] The dosing unit is used to pre-configure modified polyurethane suspended filler, modified anode electrode and modified fly ash filler according to the water quality characteristics of coking wastewater.

[0032] The biochemical tank is used to carry out biochemical reactions on the coking wastewater, and the modified polyurethane suspended packing is placed in the biochemical tank.

[0033] The electrocatalytic oxidation device is used to electrolyze the effluent from the biological treatment tank. The electrocatalytic oxidation device uses the modified anode electrode as the anode electrode and a graphite electrode as the cathode electrode.

[0034] A packed adsorption tower is used to adsorb and treat the effluent from the electrocatalytic oxidation device, and the modified fly ash packing is placed inside the packed adsorption tower.

[0035] In the deep treatment method and system for coking wastewater provided by this invention, modified polyurethane suspended packing, modified anode electrodes, and modified fly ash packing are pre-configured according to the water quality characteristics of the coking wastewater. After modification, the spatial structure connectivity of the ordinary polyurethane packing is enhanced, increasing its specific surface area. Materials such as polyhydroxybutyrate valerate adhere to the polyurethane surface, increasing the biocompatibility and chemical stability of the packing and improving the adaptability of microorganisms in aerobic and anoxic microenvironments. Simultaneously, the modified anode electrode is used as the anode of the electrocatalytic oxidation device, accelerating the electron transfer rate, improving the efficiency of the electrochemical reaction, and exhibiting better mechanical properties and bonding strength. This reduces wear and detachment during electrolysis, ensuring long-term stable operation of the electrode. Furthermore, the modified fly ash packing enhances the adsorption capacity for pollutants in the coking wastewater. Attached Figure Description

[0036] Those skilled in the art will understand that the accompanying drawings are provided to better understand the invention and do not constitute any limitation on the scope of the invention. Wherein:

[0037] Figure 1 A flowchart of a method for deep treatment of coking wastewater provided in an embodiment of the present invention;

[0038] Figure 2 This is a schematic diagram of the structure of a deep treatment system for coking wastewater provided in an embodiment of the present invention.

[0039] in:

[0040] 1 - water inlet pump; 2 - biochemical tank; 2-1 - anoxic tank; 2-2 - aerobic tank; 3 - modified polyurethane suspended filler; 4 - primary booster pump; 5 - electro-catalytic oxidation device; 6 - modified anode electrode; 7 - secondary booster pump; 8 - filler adsorption tower; 9 - modified fly ash filler; 10 - water outlet pump. DETAILED DESCRIPTION

[0041] In order to make the objects, advantages and features of the present application more clearly, the following further describes the present application in conjunction with the drawings and specific embodiments. It should be noted that the drawings are very simplified and all use non-precise proportions, only for the purpose of facilitating, clearly assisting the purpose of describing the embodiments of the present application. In order to make the objects, features and advantages of the present application more obvious and easy to understand, please refer to the drawings. It should be understood that the structures, proportions, sizes, etc. shown in the drawings attached to the present specification are only used to understand and read by those skilled in the art, and are not used to limit the conditions of the implementation of the present application. Any modification of structure, change of proportion relationship or adjustment of size, as long as it is the same or similar to the effect and purpose that can be achieved by the present application, should still fall within the scope of the technical content disclosed by the present application.

[0042] As used in the present application, the singular forms "a," "an," and "the" include plural referents unless the content clearly dictates otherwise. As used in the present application, the term "or" is generally employed in its sense of "and / or" unless the content clearly dictates otherwise. As used in the present application, the term "at least one" is generally employed in its sense of "one or more" unless the content clearly dictates otherwise. As used in the present application, the term "at least two" is generally employed in its sense of "two or more" unless the content clearly dictates otherwise. In addition, the terms "first," "second," "third," are used only for the purpose of description and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined as "first," "second," "third" can be explicitly or implicitly included one or at least two features.

[0043] In the description of the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connecting", "fixing" should be understood in a broad sense, for example, it can be fixed connection, or detachable connection, or integral; it can be mechanical connection, or electrical connection; it can be direct connection, or indirect connection through intermediate medium, it can be the connection inside two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0044] Reference should be made to Figure 1and Figure 2 The embodiment provides a coking wastewater advanced treatment method, which comprises the following steps:

[0045] S1, the modified polyurethane suspended filler 3, the modified anode electrode 6 and the modified fly ash filler 9 are configured in advance according to the water quality characteristics of the coking wastewater.

[0046] S2, the coking wastewater is sent into the biochemical pool 2 to perform biochemical reaction, and the modified polyurethane suspended filler 3 is placed in the biochemical pool 2.

[0047] S3, the effluent of the biochemical pool 2 is sent into the electro-catalytic oxidation device 5 to perform electrolysis reaction, the modified anode electrode 6 is used as the anode electrode of the electro-catalytic oxidation device 5, and a graphite electrode is used as the cathode electrode.

[0048] S4, the effluent of the electro-catalytic oxidation device 5 is sent into the filler adsorption tower 8 to perform adsorption treatment, and the modified fly ash filler 9 is placed in the filler adsorption tower 8.

[0049] The modified polyurethane suspended filler 3, the modified anode electrode 6 and the modified fly ash filler 9 for the coking wastewater advanced treatment are configured in advance according to the water quality characteristics of the coking wastewater, the space structure connectivity of the ordinary polyurethane filler is enhanced after modification, the specific surface area is improved, polyhydroxybutyrate and other materials are attached to the surface of the polyurethane, the biocompatibility and chemical stability of the filler are improved, and the adaptability of microorganisms in the aerobic and anoxic microenvironment is improved, the modified anode electrode 6 is used as the anode of the electro-catalytic oxidation device 5, the electron transfer rate is accelerated, the efficiency of the electrochemical reaction is improved, the mechanical properties and the bonding force are better, the wear and fall-off phenomena in the electrolysis process are reduced, and the long-term stable operation of the electrode is ensured. In addition, the adsorption capacity of the modified fly ash filler for pollutants in the coking wastewater is improved.

[0050] Firstly, S1 is performed, the modified polyurethane suspended filler 3, the modified anode electrode 6 and the modified fly ash filler 9 are configured in advance according to the water quality characteristics of the coking wastewater.

[0051] In the embodiment, the water quality characteristics of the coking wastewater are as follows: the TOC is 1230-2120 mg / L, the content of perfluoroalkyl compounds is 108.1-207.9 ng / L, and the total cyanide content is 6.9-9.7 mg / L.

[0052] In the embodiment, the modified polyurethane suspended filler 3 is prepared from ordinary polyurethane filler, water-soluble polyurethane solution, polyhydroxybutyrate and protease, the modified anode electrode 6 is prepared from titanium electrode plate, sulfuric acid solution, industrial petroleum ether, citric acid solution, lead nitrate, ferric chloride and ruthenium chloride, and the modified fly ash filler 9 is prepared from fly ash, alkaline steel slag, sulfuric acid solution and ferric sulfate solution.

[0053] Preferably, the method for preparing the modified polyurethane suspended filler 3 comprises:

[0054] Preparation of a water-soluble polyurethane solution with a mass percentage of 94-98%;

[0055] Add 35-67 mg of polyhydroxybutyric acid valerate and 0.5-1.3 mg of protease to each liter of the water-soluble polyurethane solution to obtain a water-soluble polyurethane mixture, and ultrasonically mix for 30-45 min;

[0056] Soak the common polyurethane filler in the water-soluble polyurethane mixture for 12-16 h, and then drain after taking out;

[0057] Put the polyurethane filler obtained after draining into an air drying oven, control the temperature of the air drying oven at 67-72℃, and keep the temperature constant for 310-420 min, and then cool to prepare the modified polyurethane suspended filler.

[0058] In this embodiment, the common polyurethane filler is square, with a size of 15*15*15 mm, a porosity of 69-73%, and a specific surface area of 320-390 m 2 / m 3 . The modified polyurethane suspended filler has a bulk density of 11.2-12.3 kg / m 3 , a porosity of 72-78%, and a specific surface area of 411-423 m 2 / m 3 .

[0059] Preferably, the method for preparing the modified anode electrode 6 comprises:

[0060] Soak the titanium plate in a 25-29% mass percentage sulfuric acid solution for 40-45 min, then soak the titanium plate in industrial petroleum ether for 20-25 min, take it out and put it into a muffle furnace, and place it in a 105℃ muffle furnace for 85-95 min, and then naturally cool it down;

[0061] Prepare a 1.9-3.8 mol / L citric acid solution, add 45-56 mg of lead nitrate, 23-34 mg of ferric trichloride, and 0.6-1.7 mg of ruthenium chloride to each liter of the citric acid solution, ultrasonically mix for 20-35 min, and form a citric acid mixed solution;

[0062] Soak the naturally cooled titanium plate in the citric acid mixed solution at a temperature of 45-56℃ for 155-310 min, then put it into a muffle furnace, first heat the muffle furnace to 211-245℃ at a rate of 2-4℃ / min for 35-46 min, then heat it to 556-623℃ at a rate of 4-5℃ / min, keep the temperature constant for 45-55 min, and cool it to room temperature to prepare the modified anode electrode 6.

[0063] In this embodiment, the thickness of the titanium electrode plate is preferably 3 mm. The oxygen evolution potential of the anode electrode before modification is 1.38 V (vs. SCE), and the oxygen evolution potential after modification is 1.55 V (vs. SCE).

[0064] Preferably, the preparation method of the modified fly ash filler 9 comprises:

[0065] Screening the fly ash with a specific surface area of 8.1-13 m 2 / g, and the alkaline steel slag with a particle size of 1-2 mm and a specific surface area of 0.2-0.4 m 2 / g, and mixing the fly ash and the alkaline steel slag in a volume ratio of 16-21:1, then mechanically stirring for 23-27 min to form a fly ash-steel slag mixture;

[0066] Preparing a sulfuric acid solution with a mass percentage of 4-7%, immersing the fly ash-steel slag mixture in the sulfuric acid solution at 55-62°C for 92-236 min, draining after taking out, and placing in a muffle furnace at 105°C for 89-125 min, and naturally cooling after taking out;

[0067] Preparing a ferric sulfate solution of 567-629 mg / L, and placing 7-9 g of the fly ash-steel slag mixture in each liter of the ferric sulfate solution;

[0068] Radiating the obtained mixed solution under a microwave power of 600 W for 15-20 min, stirring for 55-63 min, and filtering to obtain the modified fly ash filler 9 with a specific surface area of 21.2-25.5 m 2 / g, which has a strong ability to adsorb pollutants.

[0069] Then, S2 is performed, and the coking wastewater is sent into a biochemical tank 2 for biochemical reaction, and the modified polyurethane suspended filler 3 is placed in the biochemical tank 2. In this embodiment, the coking wastewater is sent into the biochemical tank 2 for biochemical reaction by the water inlet pump 1.

[0070] Preferably, the biochemical tank 2 comprises an anoxic tank 2-1 and an aerobic tank 2-2 which are sequentially connected, the filling amount of the modified polyurethane suspended filler 3 in the anoxic tank 2-1 is 23-29%, and the filling amount of the modified polyurethane suspended filler 3 in the aerobic tank 2-2 is 37-41%. The residence time of the coking wastewater in the anoxic tank 2-1 is 23-34 h, the dissolved oxygen is 0.2-0.4 mg / L, and the sludge concentration is 6020-7940 mg / L; the residence time of the coking wastewater in the aerobic tank 2-2 is 41-59 h, the dissolved oxygen is 4.5-4.7 mg / L, and the sludge concentration is 4590-5120 mg / L. The sludge reflux ratio of the biochemical tank 2 is 85%-125%, and the nitrification liquid reflux ratio is 150%-180%.

[0071] In the embodiment, the biochemical tank 2 can stably treat the coking wastewater, the modified polyurethane suspended filler 3 increases the specific surface area of the filler and improves the affinity to the microorganisms, thereby providing an excellent living environment for the microorganisms. The microbial genera in the activated sludge in the anoxic tank 2-1 are diverse, the relative abundance of the beta-proteobacteria in the main genera is 42.1-45.8%, the relative abundance of the planctomycetes is 14.3-17.2%, the relative abundance of the alpha-proteobacteria is 12.1-14.2%, and the relative abundance of the anaerolineae is 2.1-4.8%. The microbial genera in the activated sludge in the aerobic tank 2-2 are rich, the relative abundance of the beta-proteobacteria in the main genera is 37.2-41.5%, the relative abundance of the alpha-proteobacteria is 17.8-23.4%, the relative abundance of the gamma-proteobacteria is 7.5-11.2%, the relative abundance of the planctomycetes is 4.1-6.9%, and the relative abundance of the anaerolineae is 1.5-2.3%.

[0072] After the treatment by the biochemical tank 2, the TOC in the coking wastewater is 61-79 mg / L, the content of the perfluoroalkyl compounds is 45.2-97.9 ng / L, and the total cyanide content is 0.9-2.1 mg / L.

[0073] Then, S3 is performed, the effluent of the biochemical tank 2 is sent into the electro-catalytic oxidation device 5 by the primary booster pump 4 to perform electrolysis, the electro-catalytic oxidation device 5 uses the modified anode electrode 6 as the anode electrode and uses the graphite electrode as the cathode electrode. The electro-catalytic oxidation device 5 directly generates hydroxyl ions by electrolysis to degrade and remove the pollutants such as the perfluoroalkyl compounds. During the operation, the hydraulic retention time is 21-33 min, the distance between the anode electrode and the cathode electrode is 2.5 cm, and the current density is 3.3-3.9 A / m 2 .

[0074] After the treatment by the electro-catalytic oxidation device 5, the TOC in the coking wastewater is 27-33 mg / L, the content of the perfluoroalkyl compounds is 21.1-37.9 ng / L, and the total cyanide content is 0.1-0.3 mg / L.

[0075] Finally, S4 is performed, the effluent of the electro-catalytic oxidation device 5 is sent into the filler adsorption tower 8 to perform adsorption treatment, and the modified fly ash filler 9 is placed in the filler adsorption tower 8.

[0076] In the embodiment, the coking wastewater is punched into the filler adsorption tower 8 by the secondary booster pump 7, the height-diameter ratio of the filler adsorption tower 8 is 6-1, the modified fly ash filler 9 accounts for 76-82% of the entire filler adsorption tower 8 in terms of volume ratio, and the residence time of the coking wastewater in the filler adsorption tower 8 is 37-42 min.

[0077] After the adsorption treatment by the filler adsorption tower 8, the TOC in the coking wastewater is 16-18 mg / L, the content of perfluoroalkyl compounds is 13.3-16.7 ng / L, and the total cyanide content is 0.09-0.1 mg / L. Then the coking wastewater can be discharged or treated by zero discharge through the drainage pump 10, and the present application does not repeat the details.

[0078] Based on the same technical concept, the present application also provides a coking wastewater advanced treatment system for realizing the coking wastewater advanced treatment method as above, as shown in the figure, the coking wastewater advanced treatment system comprises a dosing unit and sequentially connected biochemical pool 2, electro-catalytic oxidation device 5 and filler adsorption tower 8. Figure 2

[0079] The dosing unit is used for pre-configuring the modified polyurethane suspended filler 3, the modified anode electrode 6 and the modified fly ash filler 9 according to the water quality characteristics of the coking wastewater.

[0080] The biochemical pool 2 is used for biochemical reaction of the coking wastewater, and the modified polyurethane suspended filler 3 is placed in the biochemical pool 2.

[0081] The electro-catalytic oxidation device 5 is used for electrolytic reaction of the effluent of the biochemical pool 2, and the modified anode electrode 6 is used as the anode electrode and the graphite electrode is used as the cathode electrode.

[0082] The filler adsorption tower 8 is used for adsorption treatment of the effluent of the electro-catalytic oxidation device 5, and the modified fly ash filler 9 is placed in the filler adsorption tower 8.

[0083] The technical concept of the present application is further described below through three specific embodiments.

[0084] Embodiment 1

[0085] The water quality characteristics of the coking wastewater are: TOC is 2120 mg / L, the content of perfluoroalkyl compounds is 207.9 ng / L, and the total cyanide content is 9.7 mg / L.

[0086] ​The coking wastewater is introduced into the biochemical tank 2 by the water inlet pump 1. The modified polyurethane suspended filler 3 is placed in the biochemical tank 2. The filling amount of the modified polyurethane suspended filler 3 is 29% in the anoxic tank 2-1, and the filling amount of the modified polyurethane suspended filler 3 is 41% in the aerobic tank 2-2. The residence time of the coking wastewater in the anoxic tank 2-1 is 34h, the dissolved oxygen is 0.2mg / L, and the sludge concentration is 7940mg / L. The residence time of the coking wastewater in the aerobic tank 2-2 is 59h, the dissolved oxygen is 4.7mg / L, and the sludge concentration is 5120mg / L. The sludge reflux ratio of the biochemical tank 2 is 125%, and the nitrification liquid reflux ratio is 180%. The biochemical tank 2 stably treats the coking wastewater. The modified polyurethane suspended filler 3 increases the specific surface area of the filler and improves the affinity to microorganisms, thereby providing an excellent living environment for the microorganisms. The microbial genera in the activated sludge in the anoxic tank 2-1 are diverse. The relative abundance of the main genera is 45.8% for the beta-proteobacteria, 14.3% for the planctomycetes, 12.1% for the alpha-proteobacteria, and 4.8% for the anaerolineae. The types of the microbial genera in the activated sludge in the aerobic tank 2-2 are rich. The relative abundance of the main genera is 41.5% for the beta-proteobacteria, 17.8% for the alpha-proteobacteria, 7.5% for the gamma-proteobacteria, 4.1% for the planctomycetes, and 2.3% for the anaerolineae.

[0087] The modified polyurethane suspended filler is prepared according to the characteristics of the coking wastewater. The preparation method is as follows:

[0088] The ordinary polyurethane filler is selected. The ordinary polyurethane filler is square, the size is 15*15*15mm, the porosity is 73%, and the specific surface area is 390m 2 / m 3 ;

[0089] The water-soluble polyurethane solution with a mass percentage of 98% is prepared.

[0090] 67mg of polyhydroxybutyric acid valerate, 1.3mg of protease, and the water-soluble polyurethane mixed solution are added to each liter of the water-soluble polyurethane solution, and ultrasonic treatment is performed for 45min, so that the added solid substances are fully mixed.

[0091] The ordinary polyurethane filler is immersed in the water-soluble polyurethane mixed solution for 16h, and then drained after being taken out.

[0092] The drained polyurethane filler is placed in the air drying oven, the temperature of the air drying oven is controlled at 72℃, and the constant temperature is maintained for 420min. After cooling, the modified polyurethane suspended filler is prepared.

[0093] After modification, the space structure connectivity of the filler is enhanced, the specific surface area is increased, polyhydroxybutyrate and other materials are attached to the surface of the polyurethane, the biocompatibility and chemical stability of the filler are increased, and the adaptability of microorganisms in aerobic and anoxic microenvironments is improved. In this embodiment, the bulk density of the modified polyurethane suspended filler is 12.3 kg / m 3 , the porosity is 78%, and the specific surface area is 421 m 2 / m 3 .

[0094] After treatment by the biochemical tank 2, the TOC of the coking wastewater is 79 mg / L, the content of perfluoroalkyl compounds is 97.9 ng / L, and the total cyanide content is 2.1 mg / L.

[0095] Subsequently, the coking wastewater passes through the primary lifting pump 4 into the electro-catalytic oxidation device 5, and the modified anode electrode 6 is placed at the upper part of the electro-catalytic oxidation device 5, with a graphite electrode as the cathode electrode. The electro-catalytic oxidation device 5 directly generates hydroxyl ions through electrolytic reaction to degrade and remove pollutants such as perfluoroalkyl compounds. During operation, the hydraulic retention time is 33 min, the distance between the modified anode electrode 6 and the cathode electrode is 2.5 cm, and the current density is 3.9 A / m 2 .

[0096] The modified anode electrode 6 is prepared according to the water quality characteristics of the coking wastewater, and the preparation method is as follows:

[0097] A titanium electrode plate with a thickness of 3 mm is selected, soaked in a 29% by mass sulfuric acid solution for 45 min, then soaked in industrial petroleum ether for 25 min, taken out and placed in a muffle furnace at 105°C for 95 min, and naturally cooled after taking out;

[0098] A 3.8 mol / L citric acid solution is prepared, 56 mg of lead nitrate, 34 mg of ferric trichloride, and 1.7 mg of ruthenium chloride are added to each liter of the citric acid solution, and ultrasonic treatment is performed for 35 min to form a citric acid mixed solution;

[0099] The titanium electrode plate is immersed in the citric acid mixed solution at a temperature of 56°C for 310 min, then placed in a muffle furnace, the muffle furnace is heated to 245°C at a rate of 4°C / min for 46 min, then heated to 623°C at a rate of 5°C / min, and held at this temperature for 55 min, and then cooled to room temperature to prepare the modified anode electrode 6. The oxygen evolution potential of the anode electrode before modification is 1.38 V (vs. SCE), and the oxygen evolution potential after modification is 1.55 V (vs. SCE).

[0100] After treatment by the electro-catalytic oxidation device 5, the TOC of the coking wastewater is 33 mg / L, the content of perfluoroalkyl compounds is 37.9 ng / L, and the total cyanide content is 0.3 mg / L.

[0101] The coking wastewater is pumped into the packing adsorption tower 8 by the secondary lifting pump 7. The height and diameter ratio of the packing adsorption tower 8 is 6:1. The modified fly ash packing 9 accounts for 82% of the volume of the entire packing adsorption tower 8. The residence time of the coking wastewater in the packing adsorption tower 8 is 42 min.

[0102] The modified fly ash packing 9 is prepared according to the characteristics of the coking wastewater, and the preparation method is as follows:

[0103] The fly ash with a specific surface area of 13 m 2 / g is sieved, the alkaline steel slag with a specific surface area of 0.4 m 2 / g is sieved, and the fly ash and the alkaline steel slag are mixed in a volume ratio of 21:1, and then mechanically stirred for 27 min to form a fly ash-steel slag mixture.

[0104] A 4% sulfuric acid solution by mass percentage is prepared, the fly ash-steel slag mixture is immersed in the 62℃ sulfuric acid solution for 236 min, and then drained, placed in a 105℃ muffle furnace for 125 min, and then naturally cooled.

[0105] A 629 mg / L iron sulfate solution is prepared, and 9 g of the fly ash-steel slag mixture is placed in each liter of the iron sulfate solution.

[0106] The mixed solution is irradiated for 20 min under a microwave power of 600 W, and stirred for 63 min. After filtration, the modified fly ash packing 9 with a specific surface area of 25.5 m 2 / g is prepared, which has a strong adsorption capacity for pollutants.

[0107] After the adsorption treatment by the packing adsorption tower 8, the TOC of the coking wastewater is 18 mg / L, the content of perfluoroalkyl compounds is 16.7 ng / L, and the total cyanide content is 0.1 mg / L.

[0108] Subsequently, the coking wastewater is discharged or treated by zero discharge through the drainage pump 10.

[0109] Example 2

[0110] The coking wastewater has the following characteristics: TOC is 1230 mg / L, the content of perfluoroalkyl compounds is 108.1 ng / L, and the total cyanide content is 6.9 mg / L.

[0111] The coking wastewater is pumped into the biochemical tank 2 by the water inlet pump 1. The modified polyurethane suspended filler 3 is placed in the biochemical tank 2. The filling amount of the modified polyurethane suspended filler 3 in the anoxic tank 2-1 is 23%, and the filling amount of the modified polyurethane suspended filler 3 in the aerobic tank 2-2 is 37%. The residence time of the coking wastewater in the anoxic tank 2-1 is 23h, the dissolved oxygen is 0.4mg / L, and the sludge concentration is 6020mg / L. The residence time of the coking wastewater in the aerobic tank 2-2 is 41h, the dissolved oxygen is 4.5mg / L, and the sludge concentration is 4590mg / L. The sludge reflux ratio of the biochemical tank 2 is 85%, and the nitrification liquid reflux ratio is 150%. The biochemical tank 2 stably treats the coking wastewater. The modified polyurethane suspended filler 3 increases the specific surface area of the filler and improves the affinity to microorganisms, thereby providing an excellent living environment for the microorganisms. The microbial genera in the activated sludge in the anoxic tank 2-1 are diverse. The relative abundance of the main genera β-proteobacteria is 42.1%, the relative abundance of the main genera Planctomycetes is 17.2%, the relative abundance of the main genera α-proteobacteria is 14.2%, and the relative abundance of the main genera Anaerolineae is 2.1%. The microbial genera in the activated sludge in the aerobic tank 2-2 are rich. The relative abundance of the main genera β-proteobacteria is 37.2%, the relative abundance of the main genera α-proteobacteria is 23.4%, the relative abundance of the main genera γ-proteobacteria is 11.2%, the relative abundance of the main genera Planctomycetes is 6.9%, and the relative abundance of the main genera Anaerolineae is 1.5%.

[0112] The modified polyurethane suspended filler 3 is prepared according to the characteristics of the coking wastewater, and the preparation method is as follows:

[0113] The ordinary polyurethane filler is selected, which is square, the size is 15*15*15mm, the porosity is 69%, and the specific surface area is 320m 2 / m 3 ;

[0114] The water-soluble polyurethane solution with a mass percentage of 94% is prepared;

[0115] 35mg of polyhydroxybutyric acid valerate, 0.5mg of protease, and water-soluble polyurethane mixed solution are added to each liter of the water-soluble polyurethane solution, and the solid substances are fully mixed after ultrasonic treatment for 30min;

[0116] The ordinary polyurethane filler is soaked in the water-soluble polyurethane mixed solution for 12h, and then drained after being taken out;

[0117] The polyurethane filler after draining is placed in a blast drying oven, the temperature of the blast drying oven is controlled at 67℃, and the constant temperature is maintained for 310 min. After cooling, the modified polyurethane suspension filler 3 is prepared. After modification, the space structure connectivity of the filler is enhanced, the specific surface area is increased, the polyhydroxybutyrate valerate and other materials are attached to the surface of the polyurethane, the biocompatibility and chemical stability of the filler are increased, and the adaptability of microorganisms in aerobic and anoxic microenvironments is improved. The bulk density of the modified polyurethane suspension filler 3 is 11.2 kg / m 3 , the porosity is 72%, and the specific surface area is 411 m 2 / m 3 .

[0118] After treatment by the biochemical pool 2, the TOC of the coking wastewater is 61 mg / L, the content of perfluoroalkyl compounds is 45.2 ng / L, and the total cyanide content is 0.9 mg / L.

[0119] Subsequently, the coking wastewater passes through the primary lifting pump 4 and enters the electro-catalytic oxidation device 5. The modified anode electrode 6 is placed at the upper part of the electro-catalytic oxidation device 5, and the graphite electrode is used as the cathode electrode. The electro-catalytic oxidation device 5 directly generates hydroxyl ions through an electrolytic reaction to degrade and remove pollutants such as perfluoroalkyl compounds. During operation, the hydraulic retention time is 21 min, the distance between the modified anode electrode 6 and the cathode electrode is 2.5 cm, and the current density is 3.3 A / m 2 .

[0120] The modified anode electrode 6 is prepared according to the water quality characteristics of the coking wastewater, and the preparation method is as follows:

[0121] A titanium electrode plate with a thickness of 3 mm is selected, soaked in a 25% by mass sulfuric acid solution for 40 min, then soaked in industrial petroleum ether for 20 min, taken out and placed in a muffle furnace at 105℃ for 85 min, and naturally cooled after taking out;

[0122] A 1.9 mol / L citric acid solution is prepared, 45 mg of lead nitrate, 23 mg of ferric trichloride, and 0.6 mg of ruthenium chloride are added to each liter of the citric acid solution, and ultrasonic treatment is performed for 20 min to form a citric acid mixed solution;

[0123] The titanium electrode plate is immersed in the citric acid mixed solution at a temperature of 45℃ for 155 min, then placed in a muffle furnace, the muffle furnace is heated to 211℃ at a rate of 2℃ / min for 35 min, then heated to 556℃ at a rate of 4℃ / min, and maintained at this temperature for 45 min. After cooling to room temperature, the modified anode electrode 6 is prepared.

[0124] In this embodiment, the oxygen evolution potential of the anode electrode before modification is 1.38 V (vs. SCE), and the oxygen evolution potential after modification is 1.55 V (vs. SCE).

[0125] After the electro-catalytic oxidation device 5 treatment, the coking wastewater TOC is 27 mg / L, the perfluoroalkyl compound content is 21.1 ng / L, and the total cyanide content is 0.1 mg / L.

[0126] The coking wastewater is pumped into the filler adsorption tower 8 by the secondary lifting pump 7. The height and diameter ratio of the filler adsorption tower 8 is 6:1. The modified fly ash filler 9 accounts for 82% of the entire filler adsorption tower 8 in terms of volume ratio. The residence time of the coking wastewater in the filler adsorption tower 8 is 42 min.

[0127] The modified fly ash filler 9 is prepared according to the characteristics of the coking wastewater, and the preparation method is as follows:

[0128] The fly ash with a specific surface area of 8.1 m 2 / g is sieved, and the alkaline steel slag with a particle size of 1 mm and a specific surface area of 0.2 m 2 / g is sieved. Then, the fly ash and the alkaline steel slag are mixed in a volume ratio of 16:1, and then mechanically stirred for 23 min to form a fly ash-steel slag mixture.

[0129] A 7% sulfuric acid solution by mass percentage is prepared, and the fly ash-steel slag mixture is immersed in the 55℃ sulfuric acid solution for 92 min. After draining, it is placed in a 105℃ muffle furnace for 89 min, and then naturally cooled.

[0130] A 567 mg / L iron sulfate solution is prepared, and 7 g of the fly ash-steel slag mixture is placed in each liter of the iron sulfate solution.

[0131] The mixed solution is irradiated at a microwave power of 600 W for 15 min and stirred for 55 min. After filtration, the modified fly ash filler 9 is obtained, which has a specific surface area of 21.2 m 2 / g and has a strong adsorption of pollutants.

[0132] After the adsorption treatment of the filler adsorption tower 8, the coking wastewater TOC is 16 mg / L, the perfluoroalkyl compound content is 13.3 ng / L, and the total cyanide content is 0.09 mg / L.

[0133] Subsequently, the coking wastewater is discharged or treated by zero discharge through the drainage pump 10.

[0134] Example 3

[0135] The coking wastewater has the following characteristics: TOC is 1790 mg / L, perfluoroalkyl compound content is 172.1 ng / L, and total cyanide content is 8.1 mg / L.

[0136] The coking wastewater is pumped into the biochemical tank 2 by the water inlet pump 1. The modified polyurethane suspended filler 3 is placed in the biochemical tank 2. The filling amount of the modified polyurethane suspended filler 3 in the anoxic tank 2-1 is 26%, and the filling amount of the modified polyurethane suspended filler 3 in the aerobic tank 2-2 is 39%. The residence time of the coking wastewater in the anoxic tank 2-1 is 29h, the dissolved oxygen is 0.3mg / L, and the sludge concentration is 6980mg / L. The residence time of the coking wastewater in the aerobic tank 2-2 is 50h, the dissolved oxygen is 4.6mg / L, and the sludge concentration is 4810mg / L. The sludge reflux ratio of the biochemical tank 2 is 95%, and the nitrification liquid reflux ratio is 170%. The biochemical tank 2 stably treats the coking wastewater. The modified polyurethane suspended filler 3 increases the specific surface area of the filler and improves the affinity to microorganisms, thereby providing an excellent living environment for the microorganisms. The microbial genera in the activated sludge in the anoxic tank 2-1 are diverse. The relative abundance of the main genera is 43.1% for the beta-proteobacteria, 16.2% for the planctomycetes, 13.1% for the alpha-proteobacteria, and 3.3% for the anaerolineae. The microbial genera in the activated sludge in the aerobic tank 2-2 are rich in species. The relative abundance of the main genera is 39.5% for the beta-proteobacteria, 19.7% for the alpha-proteobacteria, 9.3% for the gamma-proteobacteria, 5.2% for the planctomycetes, and 1.9% for the anaerolineae.

[0137] The modified polyurethane suspended filler 3 is prepared according to the characteristics of the coking wastewater, and the preparation method is as follows:

[0138] The ordinary polyurethane filler is selected. The size of the ordinary polyurethane filler is 15*15*15mm, the porosity is 71%, and the specific surface area is 350m 2 / m 3 ;

[0139] A water-soluble polyurethane solution with a mass percentage of 96% is prepared;

[0140] 47mg of polyhydroxybutyric acid valerate and 0.9mg of protease are added to each liter of the water-soluble polyurethane solution. The water-soluble polyurethane mixture is ultrasonically treated for 37min, and the added solid substances are fully mixed;

[0141] The ordinary polyurethane filler is immersed in the water-soluble polyurethane mixture for 14h, and then drained after being taken out;

[0142] The polyurethane filler after draining is placed in a blast drying oven, the temperature of the blast drying oven is controlled at 69℃, and the constant temperature is maintained for 386 min. After cooling, the modified polyurethane suspension filler 3 is prepared. After modification, the space structure connectivity of the filler is enhanced, the specific surface area is increased, the polyhydroxybutyrate valerate and other materials are attached to the surface of the polyurethane, the biocompatibility and chemical stability of the filler are increased, and the adaptability of microorganisms in aerobic and anoxic microenvironments is improved. The bulk density of the modified polyurethane suspension filler 3 is 11.9 kg / m 3 , the porosity is 76%, and the specific surface area is 417 m 2 / m 3 .

[0143] After treatment by the biochemical pool 2, the TOC of the coking wastewater is 66 mg / L, the content of perfluoroalkyl compounds is 56.9 ng / L, and the total cyanide content is 1.3 mg / L.

[0144] Subsequently, the coking wastewater passes through the primary lifting pump 4 and enters the electro-catalytic oxidation device 5. The modified anode electrode 6 is placed at the upper part of the electro-catalytic oxidation device 5, and the graphite electrode is used as the cathode electrode. The electro-catalytic oxidation device 5 directly generates hydroxyl ions through an electrolytic reaction to degrade and remove pollutants such as perfluoroalkyl compounds. During operation, the hydraulic retention time is 28 min, the distance between the modified anode electrode 6 and the cathode electrode is 2.5 cm, and the current density is 3.6 A / m 2 .

[0145] The modified anode electrode 6 is prepared according to the water quality characteristics of the coking wastewater, and the preparation method is as follows:

[0146] A titanium electrode plate with a thickness of 3 mm is selected, soaked in a 27% by mass sulfuric acid solution for 42 min, then soaked in industrial petroleum ether for 23 min, taken out and placed in a muffle furnace at 105℃ for 89 min, and naturally cooled after taking out;

[0147] A 2.5 mol / L citric acid solution is prepared, 51 mg of lead nitrate, 28 mg of ferric trichloride, and 1.1 mg of ruthenium chloride are added to each liter of the citric acid solution, and ultrasonic treatment is performed for 28 min to form a citric acid mixed solution;

[0148] The titanium electrode plate is immersed in the citric acid mixed solution at a temperature of 51℃ for 209 min, then placed in a muffle furnace, the muffle furnace is heated to 223℃ at a rate of 3℃ / min for 41 min, then heated to 611℃ at a rate of 5℃ / min, and maintained at this temperature for 49 min, and then cooled to room temperature to prepare the modified anode electrode 6.

[0149] In this embodiment, the oxygen evolution potential of the anode electrode before modification is 1.38 V (vs. SCE), and the oxygen evolution potential after modification is 1.55 V (vs. SCE).

[0150] After the electro-catalytic oxidation device 5 treatment, the coking wastewater TOC is 29 mg / L, the perfluoroalkyl compound content is 26.1 ng / L, and the total cyanide content is 0.2 mg / L.

[0151] The coking wastewater is pumped into the filler adsorption tower 8 by the secondary lifting pump 7. The height and diameter ratio of the filler adsorption tower 8 is 6:1. The modified fly ash filler 9 accounts for 78% of the entire filler adsorption tower 8 in terms of volume ratio. The residence time of the coking wastewater in the filler adsorption tower 8 is 39 min.

[0152] The modified fly ash filler 9 is prepared according to the characteristics of the coking wastewater, and the preparation method is as follows:

[0153] The fly ash with a specific surface area of 9.7 m 2 / g is sieved, the alkaline steel slag with a particle size of 2 mm is sieved, and the specific surface area of the steel slag is 0.3 m 2 / g, and then the fly ash and the alkaline steel slag are mixed in a volume ratio of 19:1, and then mechanically stirred for 25 min to form a fly ash-steel slag mixture;

[0154] A 5% sulfuric acid solution by mass percentage is prepared, and the fly ash-steel slag mixture is immersed in the 58℃ sulfuric acid solution for 149 min. After taking out, it is drained and placed in a 105℃ muffle furnace for 97 min. After taking out, it is naturally cooled;

[0155] A 588 mg / L iron sulfate solution is prepared, and 8 g of the fly ash-steel slag mixture is placed in each liter of the iron sulfate solution;

[0156] The mixed solution is irradiated under a microwave power of 600 W for 18 min, and stirred for 59 min. After filtration, the modified fly ash filler 9 with a specific surface area of 23.1 m 2 / g is prepared, which has a strong adsorption capacity for pollutants.

[0157] After the filler adsorption tower 8, the coking wastewater TOC is 17 mg / L, the perfluoroalkyl compound content is 14.1 ng / L, and the total cyanide content is 0.1 mg / L.

[0158] Subsequently, the coking wastewater is discharged or treated by zero discharge through the drainage pump 10.

[0159] In summary, the embodiment of the present application provides a coking wastewater advanced treatment method and system, the modified polyurethane suspended filler 3, the modified anode electrode 6 and the modified fly ash filler 9 for coking wastewater advanced treatment are pre-configured according to the water quality characteristics of coking wastewater, the space structure connectivity of the modified polyurethane filler is enhanced, the specific surface area is improved, the polyhydroxybutyric acid valerate and other materials are attached to the surface of the polyurethane, the biocompatibility and chemical stability of the filler are increased, and the adaptability of microorganisms in the aerobic and anoxic microenvironment is improved, the modified anode electrode 6 is used as the anode of the electro-catalytic oxidation device 5, the electron transfer rate is accelerated, the efficiency of the electrochemical reaction is improved, the mechanical properties and the bonding force are better, the wear and tear and the falling phenomenon in the electrolysis process can be reduced, and the long-term stable operation of the electrode is ensured.

[0160] In addition, it should be appreciated that, although the present application has been disclosed with the preferred embodiments as above, the above embodiments are not intended to limit the present application. For any skilled person in the art, many possible changes and modifications or equivalent embodiments of the above disclosed technical content can be made without departing from the scope of the present application. Therefore, any simple modification, equivalent change and modification of the above embodiments made according to the technical essence of the present application without departing from the content of the present application shall still fall within the scope of protection of the present application.

Claims

1. A method for advanced treatment of coking wastewater, characterized by, Comprising: a modified polyurethane suspended filler, a modified anode electrode and a modified fly ash filler are pre-configured according to the water quality characteristics of coking wastewater; the coking wastewater is sent into a biochemical tank for biochemical reaction, and the modified polyurethane suspended filler is placed in the biochemical tank; the effluent of the biochemical tank is sent into an electro-catalytic oxidation device for electrolysis reaction, and the electro-catalytic oxidation device uses the modified anode electrode as the anode electrode and a graphite electrode as the cathode electrode; the effluent of the electro-catalytic oxidation device is sent into a filler adsorption tower for adsorption treatment, and the modified fly ash filler is placed in the filler adsorption tower; the preparation method of the modified polyurethane suspended filler comprises: a water-soluble polyurethane solution with a mass percentage of 94-98% is prepared; 35-67 mg of polyhydroxybutyric acid valerate and 0.5-1.3 mg of protease are added to each liter of the water-soluble polyurethane solution to obtain a water-soluble polyurethane mixture, and ultrasonic treatment is performed for 30-45 min for sufficient mixing; the ordinary polyurethane filler is immersed in the water-soluble polyurethane mixture for 12-16 h, and then drained after being taken out; the polyurethane filler obtained after draining is placed in a blast drying oven, and the temperature of the blast drying oven is controlled at 67-72℃, and the constant temperature is maintained for 310-420 min, and the modified polyurethane suspended filler is prepared after cooling; the preparation method of the modified anode electrode comprises: the titanium electrode plate is soaked in a 25-29% mass percentage sulfuric acid solution for 40-45 min, then soaked in industrial petroleum ether for 20-25 min, taken out and placed in a muffle furnace at 105℃ for 85-95 min, and then naturally cooled down; a 1.9-3.8 mol / L citric acid solution is prepared, 45-56 mg of lead nitrate, 23-34 mg of ferric trichloride and 0.6-1.7 mg of ruthenium chloride are added to each liter of the citric acid solution, ultrasonic treatment is performed for 20-35 min to form a citric acid mixed solution; the naturally cooled titanium electrode plate is immersed in the citric acid mixed solution at a temperature of 45-56℃ for 155-310 min, and then placed in the muffle furnace, the muffle furnace is first heated to 211-245℃ at a rate of 2-4℃ / min for 35-46 min, and then heated to 556-623℃ at a rate of 4-5℃ / min for 45-55 min, and then cooled to room temperature to prepare the modified anode electrode; the preparation method of the modified fly ash filler comprises: powdered fly ash with a specific surface area of 8.1-13 / g and alkaline steel slag with a particle size of 1-2 mm and a specific surface area of 0.2-0.4 / g are mixed in a volume ratio of 16-21:1, and then mechanically stirred for 23-27 min to form a fly ash-steel slag mixture; A sulfuric acid solution with a quality percentage of 4-7% is prepared, and the fly ash-steel slag mixture is immersed in the sulfuric acid solution at 55-62 ℃ for 92-236 min, drained after being taken out, placed in a muffle furnace at 105 ℃ for 89-125 min, and naturally cooled after being taken out; An iron sulfate solution with a concentration of 567-629 mg / L is prepared, and 7-9 g of the fly ash-steel slag mixture is placed in each liter of the iron sulfate solution; The obtained mixed solution is irradiated at a microwave power of 600 W for 15-20 min, stirred for 55-63 min, and filtered to obtain the modified fly ash filler.

2. The method for the advanced treatment of coking wastewater according to claim 1, characterized in that, The biochemical tank comprises an anoxic tank and an aerobic tank connected in sequence, and the filling amount of the modified polyurethane suspended filler in the anoxic tank is 23-29%; the filling amount of the modified polyurethane suspended filler in the aerobic tank is 37-41%.

3. The method for advanced treatment of coking wastewater according to claim 2, characterized in that, The residence time of the coking wastewater in the anoxic tank is 23-34 h, in the aerobic tank is 41-59 h, in the electro-catalytic oxidation device is 21-33 min, and in the filler adsorption tower is 37-42 min.

4. The method for the advanced treatment of coking wastewater according to claim 1, characterized in that, The distance between the anode electrode and the cathode electrode is 2.5 cm, and the current density is 3.3-3.9 A / cm2.

5. The method for advanced treatment of coking wastewater according to claim 1, characterized in that, The height-to-diameter ratio of the filler adsorption tower is 6:1, and the modified fly ash filler accounts for 76-82% of the entire filler adsorption tower in terms of volume ratio.

6. A coking wastewater advanced treatment system for implementing the coking wastewater advanced treatment method according to any one of claims 1-5, characterized in that, The system comprises a dispensing unit and a biochemical tank, an electro-catalytic oxidation device, and a filler adsorption tower connected in sequence. The dispensing unit is configured to pre-configure modified polyurethane suspended filler, modified anode electrode, and modified fly ash filler according to the water quality characteristics of the coking wastewater. The biochemical tank is configured to perform biochemical reaction on the coking wastewater, and the modified polyurethane suspended filler is placed in the biochemical tank. The electro-catalytic oxidation device is configured to perform electrolysis reaction on the effluent of the biochemical tank, and the modified anode electrode is used as the anode electrode, and a graphite electrode is used as the cathode electrode. The filler adsorption tower is configured to perform adsorption treatment on the effluent of the electro-catalytic oxidation device, and the modified fly ash filler is placed in the filler adsorption tower.

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