Process for enhanced removal of nitrogen from industrial wastewater

Abstract

The application provides a process for enhanced removal of nitrogen in industrial wastewater, comprising providing an enhanced removal system for nitrogen in industrial wastewater, comprising an anoxic moving bed biofilm system, an aerobic moving bed biofilm system and a secondary sedimentation tank arranged in series; providing modified suspended biological filler: polyurethane filler impregnated with composite soluble metal salt; the composite soluble metal salt comprises iron salt, copper salt, calcium salt, manganese salt, cobalt salt, magnesium salt and zinc salt; the modified suspended biological filler is added into a first preset area in the anoxic moving bed biofilm system and a second preset area in the aerobic moving bed biofilm system, respectively; the industrial wastewater is fed into the enhanced removal system for nitrogen in industrial wastewater, subjected to anoxic biological treatment in the anoxic moving bed biofilm system and subjected to aeration treatment in the aerobic moving bed biofilm system. The process can enhance the high-efficiency removal of nitrogen-containing pollutants by the biological treatment system of industrial wastewater (such as coking wastewater), and meet the requirement of stable discharge of effluent water.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wastewater treatment, and particularly relates to a nitrogen element reinforced removal process in industrial wastewater. BACKGROUND

[0002] Coking wastewater is a kind of high-concentration industrial organic wastewater with complex components, which is generated in the processes of high-temperature dry distillation, gas purification and by-product recovery of raw coal in the coking process. Due to the differences in the quality of raw coal, carbonization temperature and coking process adopted by different coking plants, the chemical compositions of wastewater in different regions are not the same and the water quantity also changes greatly. This kind of wastewater has many types of pollutants with high concentration, and the main organic components are phenols, and others include polycyclic aromatic hydrocarbons and some heterocyclic compounds containing nitrogen, oxygen and sulfur. Inorganic components include cyanide (CN - ), thiocyanate (SCN - ) and ammonia nitrogen (NH4 + -N), etc. Among them, polycyclic aromatic hydrocarbons and cyanide, thiocyanate and other nitrogen-containing compounds are toxic, and their residues in water bodies have great health threats to animals, plants and humans.

[0003] At present, the commonly used biological treatment method in China is still the A / O, A 2 / O and O / A / O processes based on activated sludge method. The treatment utilizes the biological flocculation, adsorption and oxidation of activated sludge in the system to decompose and remove organic matter in wastewater. The supernatant is separated in the secondary sedimentation tank, and the supernatant is returned to the front end of the anoxic zone for denitrification. Most of the sludge is returned to the front end of the aerobic zone to maintain a certain sludge concentration, and the remaining sludge is discharged from the system.

[0004] However, due to the differences in the quality of raw coal mined in the coking process, production requirements and production process adjustment, the coking wastewater has high COD, ammonia nitrogen, organic nitrogen and total nitrogen content, and the water quality and water quantity have great fluctuation. Therefore, the coking wastewater treatment system based on the traditional activated sludge process usually has the problems of unstable nitrification function and low total nitrogen removal rate. It is difficult to meet the indirect discharge limits (25 mg / L and 50 mg / L) of ammonia nitrogen and total nitrogen specified in the Coking Chemical Industry Pollutant Discharge Standard (GB 16171-2012) for the treatment of wastewater ammonia nitrogen and total nitrogen. Therefore, an efficient coking wastewater treatment process technology is needed to achieve effective removal of nitrogen-containing pollutants to meet the requirements of stable discharge of effluent ammonia nitrogen and total nitrogen. SUMMARY

[0005] Therefore, the purpose of the present application is to provide a nitrogen element reinforced removal process in industrial wastewater.

[0006] In order to achieve the above purpose, the present application provides a nitrogen element reinforced removal process in industrial wastewater, which comprises:

[0007] The system for enhanced removal of nitrogen in industrial wastewater comprises an anoxic moving bed biofilm system, an aerobic moving bed biofilm system and a secondary sedimentation tank arranged in series.

[0008] The modified suspended biological filler comprises polyurethane filler impregnated with a composite soluble metal salt.

[0009] The modified suspended biological filler is added into a first preset area in the anoxic moving bed biofilm system and a second preset area in the aerobic moving bed biofilm system.

[0010] The industrial wastewater is fed into the system for enhanced removal of nitrogen in industrial wastewater, and subjected to anoxic biological treatment in the anoxic moving bed biofilm system and aerobic treatment in the aerobic moving bed biofilm system.

[0011] In some embodiments, the modified suspended biological filler is prepared by:

[0012] The soluble iron salt, the soluble copper salt, the soluble calcium salt, the soluble manganese salt, the soluble cobalt salt, the soluble magnesium salt and the soluble zinc salt are configured into a composite soluble metal salt mixed solution, wherein the molar ratio of the soluble iron salt, the soluble copper salt, the soluble calcium salt, the soluble manganese salt, the soluble cobalt salt, the soluble magnesium salt and the soluble zinc salt is (1.64-32.89):(0.74-22.22):(0.45-22.52):(0.26-9.94):(0.32-6.45):(0.42-16.67):(0.25-12.42).

[0013] The phosphate buffer solution has a concentration of 0.05-0.5 mol / L and a pH of 7.5-8.5.

[0014] The polyurethane filler of a preset size, the composite soluble metal salt mixed solution and the phosphate buffer solution are stirred and mixed, and then dried to obtain the modified suspended biological filler, wherein the mixing volume ratio of the polyurethane filler, the composite soluble metal salt mixed solution and the phosphate buffer solution is (20%-30%):(40%-60%):(30%-50%).

[0015] In some embodiments, the concentration of the phosphate buffer solution is 0.2-0.35 mol / L; the mixing volume ratio of the polyurethane filler, the composite soluble metal salt mixed solution and the phosphate buffer solution is (20%-25%):(40%-45%):(35%-40%); and the concentration of the phosphate buffer solution is 0.2-0.35 mol / L.

[0016] In some embodiments, the impregnation stirring mixing comprises: impregnation stirring temperature 20-40℃, impregnation stirring time length 15-30h; the drying temperature is 30-45℃, and the time length is 10-15h. The impregnation stirring time length is preferably 20-24h.

[0017] In some embodiments, the volume ratio of the modified suspended biological filler to the anoxic moving bed biofilm system is 35%-50%;

[0018] The volume ratio of the modified suspended biological filler to the anoxic moving bed biofilm system is 15%-40%.

[0019] In some embodiments, the volume ratio of the modified suspended biological filler to the anoxic moving bed biofilm system is 40%-45%;

[0020] The volume ratio of the modified suspended biological filler to the anoxic moving bed biofilm system is 20%-25%.

[0021] In some embodiments, the aerobic moving bed biofilm system comprises a plurality of aerobic units arranged in series, and the modified suspended biological filler is uniformly distributed in the plurality of aerobic units.

[0022] In the aerobic unit, the dissolved oxygen concentration in the second preset area is 4-5mg / L, and the dissolved oxygen concentration in other areas is 2-3mg / L.

[0023] In some embodiments, a first screen is arranged at the overflow weir of the anoxic moving bed biofilm system; a second screen is arranged in each of the plurality of aerobic units; at the site of the second screen, the pool width: pool length of the aerobic moving bed biofilm system is 1:1-1:2.5, preferably 1:1; the width of the second screen is 1-1.5cm; the volume ratio of the aerobic unit except the second screen to the total volume of the aerobic unit is 1:2-1:1.25, preferably 1:1.5.

[0024] In some embodiments, the flow rate of the sludge-water mixture at the end of the aerobic moving bed biofilm system backflowing to the front end of the anoxic moving bed biofilm system is 250%-550%, preferably 400%-500% of the industrial wastewater inflow; the flow rate of the sludge in the secondary sedimentation tank backflowing to the front end of the aerobic moving bed biofilm system is 100%-180%, preferably 140%-150% of the industrial wastewater inflow.

[0025] In some embodiments, the industrial wastewater is selected from coking wastewater, amino acid production wastewater, pharmaceutical wastewater, printing and dyeing wastewater, or coal gasification wastewater; the nitrogen includes at least one of nitrogen-containing heterocyclic compounds, ammonia nitrogen, cyanide and thiocyanate.

[0026] From the above, it can be seen that the process for enhanced removal of nitrogen in industrial wastewater provided by the present application promotes the attachment and growth of denitrifying bacteria on the modified suspended biological filler in the anoxic moving bed biofilm system and the attachment and growth of nitrifying bacteria on the modified suspended biological filler in the aerobic moving bed biofilm system, respectively, by adding high-quality modified suspended biological filler into the structures of the anoxic moving bed biofilm system and the aerobic moving bed biofilm system, so that the two key denitrifying microorganisms are separated in ecological niche and retained in the optimal reaction zone, respectively, so as to fully exert the denitrification and nitrification functions of the two microorganisms; at the same time, the addition of the modified suspended biological filler can also improve and maintain a high biomass and biological activity; finally, the dissolved oxygen gradient environment formed inside the modified suspended biological filler in the aerobic moving bed biofilm system can realize simultaneous nitrification and denitrification, further promoting the removal of nitrogen. The method of the present application can enhance the efficient removal of nitrogen-containing pollutants by the biological treatment system of industrial wastewater (such as coking wastewater), meeting the requirements of stable discharge of effluent. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the present application or related art, the following will briefly introduce the drawings needed to be used in the embodiments or related art descriptions. Obviously, the drawings in the following description are only embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0028] Figure 1 The flowchart of the process for enhanced removal of nitrogen in industrial wastewater of the embodiments of the present application;

[0029] Figure 2 The schematic diagram of the system for enhanced removal of nitrogen in industrial wastewater of the embodiments of the present application;

[0030] Figure 3a The schematic diagram of the suspended biological filler of test group 1 in Example 3;

[0031] Figure 3b The schematic diagram of the suspended biological filler of test group 2 in Example 3;

[0032] Figure 3c The schematic diagram of the suspended biological filler of test group 3 in Example 3;

[0033] Figure 4 The flowchart of the anoxic / aerobic moving bed biofilm process of the embodiments of the present application. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solutions and advantages of the present application more clear, the following will further describe the present application in combination with specific embodiments and with reference to the drawings.

[0035] It should be noted that, unless otherwise defined, technical or scientific terms used in the embodiments of the present application should be understood as having the same meaning as commonly understood by one of ordinary skill in the art to which the embodiments of the present application belong. The terms "first", "second" and similar terms used in the embodiments of the present application do not denote any order, quantity or importance, but are only used to distinguish different components. The terms "include" or "contain" and similar terms mean that the elements or objects before the terms encompass the elements or objects listed after the terms and their equivalents, and do not exclude other elements or objects. The terms "connect" or "connected" and similar terms are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect.

[0036] The microbial degradation and removal of nitrogen-containing pollutants in wastewater mainly includes the denitrification process under anoxic conditions, in which functional bacteria participate in the denitrification process with nitrate nitrogen as the electron acceptor, and the nitrification process under aerobic conditions, in which nitrifying bacteria participate in the oxidation of ammonia nitrogen to nitrate nitrogen. Among them, the nitrification process is the key rate-limiting step, and the autotrophic nitrifying bacteria mainly involved in the nitrification process are a kind of bacteria with low growth rate and require suitable pH (7-8), dissolved oxygen DO (> 2 mg / L), temperature T (> 15℃), sludge age SRT (> 10d) and other operating environments. The fluctuation of water quality and quantity in coking wastewater production and seasonality will cause changes in operating environment, thereby affecting the survival and activity of nitrifying bacteria and the instability of nitrification function. In addition, the refining process of chemical products in the coking process will also discharge high-concentration toxic pollutants such as phenol (609±329mg / L), thiocyanate (405±195mg / L), cyanide (17±5mg / L) and the like, and these toxic substances also have an inhibitory effect on the content and activity of denitrifying and nitrifying functional microorganisms, thereby affecting the overall nitrogen removal efficiency.

[0037] Therefore, in order to improve the nitrogen removal performance of the coking wastewater biological treatment system, it is urgent to develop a new biological denitrification treatment process to ensure that the effluent meets the discharge standard and reduce the cost of subsequent advanced treatment.

[0038] Therefore, in order to improve the nitrogen removal performance of the coking wastewater biological treatment system, it is urgent to develop a new biological denitrification treatment process to ensure that the effluent meets the discharge standard and reduce the cost of subsequent advanced treatment.

[0039] As shown in Figure 1 The nitrogen removal process provided by the embodiments of the present application can include:

[0040] At step S100, a system for enhanced removal of nitrogen in industrial wastewater is provided, which comprises an anoxic moving bed biofilm system, an aerobic moving bed biofilm system and a secondary sedimentation tank arranged in series;

[0041] At step S200, a modified suspended biological filler is provided; the modified suspended biological filler comprises polyurethane filler impregnated with a composite soluble metal salt; the composite soluble metal salt comprises iron salt, copper salt, calcium salt, manganese salt, cobalt salt, magnesium salt and zinc salt;

[0042] At step S300, the modified suspended biological filler is added into the anoxic moving bed biofilm system and the aerobic moving bed biofilm system, respectively;

[0043] At step S400, the industrial wastewater is fed into the system for enhanced removal of nitrogen in industrial wastewater, biological treatment is performed in the anoxic moving bed biofilm system, and aeration treatment is performed in the aerobic moving bed biofilm system.

[0044] By adding high-quality modified suspended biological fillers into the structures of the anoxic moving bed biofilm system and the aerobic moving bed biofilm system, respectively, the present embodiment promotes the attachment and growth of denitrifying bacteria on the modified suspended biological fillers in the anoxic moving bed biofilm system and the attachment and growth of nitrifying bacteria on the modified suspended biological fillers in the aerobic moving bed biofilm system, so that the two key denitrification microorganisms are separated in ecological niche and retained in the optimal reaction zones, respectively, so as to fully exert the denitrification and nitrification functions of the two microorganisms; meanwhile, the addition of the modified suspended biological fillers can also improve and maintain a high biomass and biological activity; finally, the dissolved oxygen gradient environment formed in the modified suspended biological fillers in the aerobic moving bed biofilm system can realize simultaneous nitrification and denitrification, further promoting the removal of nitrogen. The method of the present embodiment can enhance the efficient removal of nitrogen-containing pollutants by the biological treatment system of industrial wastewater (such as coking wastewater), so as to meet the requirement of stable discharge of effluent water.

[0045] In some embodiments of step S100, the industrial wastewater is selected from coking wastewater, amino acid production wastewater, pharmaceutical wastewater, printing and dyeing wastewater, or coal gasification wastewater, etc. The coking wastewater is a mixture of various wastewaters generated and discharged in the coal coking production process of a coal coking plant, which can specifically include residual ammonia water generated in coal dry distillation and coal gas cooling, coal gas final cooling water and crude benzene separation water generated in the coal gas purification process, wastewater generated in the refining process of tar and crude benzene, and circulating system discharge sewage, etc. The nitrogen in the industrial wastewater can be understood as all nitrogen-containing pollutants, such as nitrogen-containing heterocyclic compounds, and inorganic nitrogen-containing components such as ammonia nitrogen, cyanide and thiocyanate.

[0046] In some embodiments, a first grid 3 is arranged at the overflow weir of the anoxic moving bed biofilm system. The anoxic moving bed biofilm system can be understood as a pool-like structure formed by a structure. The first grid 3 can be a stainless steel grid, and the side length (i.e. width) can be 1-1.5 cm, and the length can be the same as the pool-like structure formed by the structure. The modified suspended biological filler can be prevented from flowing into the aerobic moving bed biofilm system by arranging the first grid.

[0047] In some embodiments, the aerobic moving bed biofilm system comprises a plurality of aerobic units arranged in series. As shown in the figure, the aerobic units can be arranged in three, for example. The aerobic moving bed biofilm system can be understood as a pool-like structure formed by a structure. The aerobic units can be separated by a second grid 4, i.e. the pool-like structure is divided into a plurality of aerobic units by a plurality of second grids 4. In another embodiment, the aerobic units can be arranged with a spacing, e.g. there is a spacing area between the aerobic units, and the aerobic units are not arranged in close proximity. Figure 2

[0048] In some embodiments, a second grid 4 is arranged in each of the plurality of aerobic units. At the site of the second grid 4, the pool width: pool length of the aerobic moving bed biofilm system is 1:1-1:2.5, preferably 1:1; the width of the second grid 4 is 1-1.5 cm; the volume of the aerobic unit excluding the second grid 4 accounts for 1:2-1:1.25, preferably 1:1.5, of the total volume of the aerobic unit. The second grid 4 can be a stainless steel grid, and the side length (i.e. width) can be 1-1.5 cm, and the length can be the same as the pool-like structure formed by the structure. The modified suspended biological filler can be prevented from accumulating at the water outlet by arranging the second grid.

[0049] In some embodiments, an aeration device, such as an aeration disc 2, can also be arranged in the aerobic moving bed biofilm system. The aeration disc 2 can be arranged uniformly and at intervals in each aerobic pool.

[0050] In some embodiments, in step S200, the modified suspended biological filler comprises:

[0051] ​In step S201, soluble iron salt, soluble copper salt, soluble calcium salt, soluble manganese salt, soluble cobalt salt, soluble magnesium salt and soluble zinc salt are configured into a composite soluble metal salt mixed solution; wherein the molar ratio of the soluble iron salt, the soluble copper salt, the soluble calcium salt, the soluble manganese salt, the soluble cobalt salt, the soluble magnesium salt and the soluble zinc salt is (1.64-32.89):(0.74-22.22):(0.45-22.52):(0.26-9.94):(0.32-6.45):(0.42-16.67):(0.25-12.42). In the composite soluble metal salt, each metal salt can be independently selected from one of a sulfate salt, a chloride salt or a nitrate salt. Through the trace composite metal, the growth and reproduction of microorganisms can be promoted, important growth factors and enzyme activators in microbial cells are provided, enzymes necessary for microorganisms to produce metabolism can be activated, and cell synthesis and metabolism activity can be enhanced; at the same time, positively charged trace metals can combine with anions in sludge to promote cell combination to form a bacterial population. In addition, to some extent, the trace composite metal can enter the active center of the enzyme of the microbial cell, and may, to some extent, participate in and promote the electron transfer efficiency of the oxidation-reduction reaction occurring in the cell, thereby improving the removal effect of pollutants.

[0052] Further, the molar ratio of the soluble iron salt, the soluble copper salt, the soluble calcium salt, the soluble manganese salt, the soluble cobalt salt, the soluble magnesium salt and the soluble zinc salt can be 6.58:4.44:3.15:1.32:0.97:2.50:1.24.

[0053] In step S202, a phosphate buffer solution is provided, the concentration of the phosphate buffer solution can be 0.05-0.5 mol / L, and the pH is 7.5-8.5. The phosphate buffer solution can be prepared by uniformly mixing Na2HPO4 and KH2PO4. KH2PO4 in the phosphate buffer solution can be replaced by NaH2PO4. In some embodiments, the molar ratio of Na2HPO4 and KH2PO4 can be (0.10-0.25):(0.15-0.30), that is, the mass ratio of Na2HPO4 and KH2PO4 can be (1.42-3.55):(2.04-4.08).

[0054] In some embodiments, the concentration of the phosphate buffer solution can be 0.2-0.35 mol / L;

[0055] In step S203, a pre-sized polyurethane filler, the composite soluble metal salt mixture, and the phosphate buffer solution are impregnated, stirred, and mixed, and then dried to obtain the modified suspended biological filler; wherein the volume ratio of the polyurethane filler, the composite soluble metal salt mixture, and the phosphate buffer solution is (20%-30%):(40%-60%):(30%-50%). After drying, multiple metal components can be immobilized on the filler.

[0056] In some embodiments, the volume ratio of the polyurethane filler, the composite soluble metal salt mixture, and the phosphate buffer solution is (20%–25%):(40%–45%):(35%–40%); and the concentration of the phosphate buffer solution is 0.2–0.35 mol / L.

[0057] In some embodiments, the impregnation and stirring process includes: an impregnation and stirring temperature of 20–40°C and an impregnation and stirring time of 15–30 h; and a drying temperature of 30–45°C and a drying time of 10–15 h. The preferred impregnation and stirring time is 20–24 h.

[0058] In some embodiments, the polyurethane foam can be a cubic structure. The size is 1cm*1cm*1cm to 3cm*3cm*3cm, preferably 2cm*2cm*2cm. That is, the preset size can be 1cm*1cm*1cm to 3cm*3cm*3cm, preferably 2cm*2cm*2cm.

[0059] In some embodiments, in step S300, the addition can be understood as the direct addition of the modified suspended biological packing. In this way, the modified suspended biological packing is in a free-flowing dynamic state in the moving bed biofilm system, thus exhibiting better mass transfer efficiency. Furthermore, it can collide with sludge and other contaminants during the flow, shedding some poorly performing bacteria, thereby achieving a suitable biofilm thickness. This avoids excessive biofilm thickness that prevents oxygen from entering, creating a large anaerobic zone and reducing mass transfer efficiency.

[0060] In some embodiments, the volume ratio of the modified suspended biological packing material to the anoxic moving bed biofilm system is 35%–50%; the volume ratio of the modified suspended biological packing material to the aerobic moving bed biofilm system is 15%–40%. The sizes of the first preset region and the second preset region can be the same or different, depending on actual needs. By adding the modified suspended biological packing material only to the first and second preset regions, the modified suspended biological packing material can achieve good flowability in both the anoxic and aerobic moving bed biofilm systems.

[0061] Specifically, in the anoxic moving bed biofilm system, a certain volume ratio (for example, the aforementioned volume ratio) of modified suspended biological filler is added in situ to the anoxic tank. Similarly, in the aerobic moving bed biofilm system, a certain volume ratio (for example, the aforementioned volume ratio) of suspended biological filler is added in situ.

[0062] In some embodiments, after the industrial wastewater enters the anoxic moving bed biofilm system in step S400, the solid-liquid phases can be uniformly mixed under the action of the tank bottom agitator, and the denitrifying microorganisms mainly grow in an attached state. In combination with the suspended microorganisms, the extracellular enzymes hydrolyze the nitrogen-containing organic matter and inorganic matter (sulfocyanide, cyanide) in the coking wastewater into ammonia nitrogen and carbon dioxide. In the anoxic moving bed biofilm system, after the modified suspended biological filler is added in situ, the biofilm formation time of the microorganisms can be 5-7 days.

[0063] Generally, the nitrogen-enhanced removal system (i.e., the anoxic / aerobic moving bed biofilm system) has a treatment load of >0.4 kg COD / m 3 / d, preferably 0.6-1.2 kg COD / m 3 / d, and further preferably 0.8-1.0 kg COD / m 3 / d during the treatment process.

[0064] In some embodiments, the nitrogen-enhanced removal system (i.e., the anoxic / aerobic moving bed biofilm system) has a total nitrogen load of >0.035 kg TN / m 3 / d, preferably 0.075-0.095 kg TN / m 3 / d during the treatment process.

[0065] In some embodiments, the nitrogen-enhanced removal system (i.e., the anoxic / aerobic moving bed biofilm system) has a hydraulic retention time (HRT) of 2.4-6.5 days during the treatment process.

[0066] After the industrial wastewater is treated by the anoxic moving bed biofilm system, the refractory organic matter is hydrolyzed and converted into easily biodegradable small molecular substances by the extracellular enzymes of the microorganisms, thereby improving the biodegradability of the wastewater and facilitating the subsequent aerobic biological treatment. The hydrolysis products of the nitrogen-containing organic matter and inorganic matter, i.e., ammonia nitrogen, enter the aerobic moving bed biofilm system for efficient nitrification conversion.

[0067] After the industrial wastewater is treated by the anoxic moving bed biofilm system, the industrial wastewater enters the aerobic moving bed biofilm system, and after the modified suspended biological filler is added in situ, the biofilm formation time of the microorganisms can be 6-9 days.

[0068] In the aerobic moving bed biofilm system, the dissolved oxygen concentration in the second preset area can be 4-5 mg / L by aeration treatment, and the dissolved oxygen concentration in other areas is 2-3 mg / L. In this way, by reasonable aeration intensity, secondly, reasonable aeration mode, uniformly interval arrangement of aeration disc 2, the modified filler rises and then settles in the area without shear force around, so as to maintain a good fluidized state. Under the action of aeration, it can present a good fluidized state, which can not only avoid too thick biofilm causing too much dead mud, leading to low oxygen transfer efficiency, but also avoid too thin biofilm, leading to low biomass and small internal anoxic space, and relatively weak ability to realize simultaneous nitrification and denitrification. Specifically, the modified suspended biological filler has a porous structure, and the density is only about 0.98±0.03 g / cm 3 At the initial stage, the filler floats under the shear force of the bubbles; after the successful biofilm formation of microorganisms, the density of the filler is slightly heavier than water, at this time, under the action of gravity and aeration, the filler will have up and down floating, so as to realize sufficient contact with industrial wastewater; and realize uniform mixing of solid-liquid-gas three phases, the filler is enriched with growth of ammonia-oxidizing bacteria with high ammonia oxidation activity and nitrite-oxidizing bacteria with high nitrite oxidation activity, so as to fully play the nitrification function, the ammonia-oxidizing bacteria first oxidize ammonia nitrogen into nitrite nitrogen, and the nitrite-oxidizing bacteria further oxidize the nitrite nitrogen into nitrate nitrogen.

[0069] In some embodiments, when the aerobic moving bed biofilm system is treated, the alkalinity is also controlled to meet the requirement of 7.14 g of bicarbonate (calculated as CaCO3) alkalinity per g of ammonia nitrogen for oxidation, and when the alkalinity is found to be insufficient, sodium hydroxide or sodium carbonate is supplemented in time, preferably sodium hydroxide.

[0070] After the coking wastewater is treated by the aerobic moving bed biofilm system, the biodegradable nitrogen-containing substances are mainly converted into nitrate nitrogen, in addition, after the successful biofilm formation of the aerobic suspended filler, a good dissolved oxygen concentration gradient is formed in the filler, which is beneficial to the removal of nitrogen by simultaneous nitrification and denitrification.

[0071] In some embodiments, the influent of the secondary sedimentation tank is the mixed liquor of activated sludge at the end of the aerobic moving bed biofilm system.

[0072] In particular, the mixed liquor of activated sludge is refluxed to the front end of the anoxic moving bed biofilm system for denitrification to reduce nitrogen gas, and finally realizes stable and efficient nitrogen removal, and the rest is separated in the secondary sedimentation tank, and the sludge is refluxed to the front end of the aerobic moving bed biofilm system. The purpose of sludge reflux is to maintain the suspended sludge biomass of the aerobic moving bed biofilm system.

[0073] In some embodiments, the sludge return ratio of the secondary sedimentation tank is 100% to 180%, preferably 140 to 150%, and the sludge-water mixture return ratio at the end of the aerobic moving bed biofilm system is 250% to 550%, preferably 400 to 500%. That is, the flow rate of the sludge-water mixture at the end of the aerobic moving bed biofilm system returned to the front end of the anoxic moving bed biofilm system is 250% to 550%, preferably 140 to 150%, of the influent amount of industrial wastewater, and the flow rate of the sludge in the secondary sedimentation tank returned to the front end of the aerobic moving bed biofilm system is 100% to 180%, preferably 400 to 500%, of the influent amount of industrial wastewater.

[0074] In some embodiments, the ammonia nitrogen concentration of the effluent after the coking wastewater is treated by the anoxic / aerobic moving bed biofilm system is less than 5 mg / L, preferably less than 3.0 mg / L, meeting the direct discharge standard.

[0075] In some embodiments, the total nitrogen concentration of the effluent after the coking wastewater is treated by the anoxic / aerobic moving bed biofilm system is less than 50 mg / L, preferably less than 40 mg / L, meeting the indirect discharge standard.

[0076] In some embodiments, the pH of the effluent after the coking wastewater is treated by the anoxic / aerobic moving bed biofilm system is 6.8 to 8.5, preferably 7.2 to 8.0, and further preferably 7.5 to 7.85.

[0077] The present application is directed to the current activated sludge treatment system for coking wastewater, which often causes unstable nitrification function and low long-term total nitrogen removal rate, and the effluent exceeds the standard. By adding modified suspended biological fillers to the anoxic tank and the aerobic tank in situ, and by setting a screen to prevent the modified suspended biological fillers from flowing between the aerobic tank and the anoxic tank, the denitrifying bacteria and nitrifying bacteria can be significantly enriched, respectively, and the ecological niche separation of heterotrophic bacteria and autotrophic nitrifying bacteria can be achieved, thereby strengthening the denitrification and nitrification functions. Finally, the simultaneous nitrification and denitrification process in the aerobic tank filler is combined to achieve efficient and stable removal of nitrogen-containing pollutants in wastewater. The combined treatment process has strong resistance to water inflow load impact. The method of the present application has the following advantages:

[0078] 1. The method of the present application can directly enter the continuous flow anoxic / aerobic moving bed biofilm system through the strengthened treatment of nitrogen in coking wastewater, without the need for a front-stage anaerobic tank in the traditional treatment process, thereby saving land area and energy consumption. The treatment load of the method of the present application can reach 0.8 to 1.0 kg COD / m 3 / d, 0.075 to 0.09 kg TN / m 3 / d, the ammonia nitrogen concentration of the effluent after treatment is less than 3.0 mg / L, meeting the direct discharge standard, and the total nitrogen concentration is stably less than 50 mg / L, meeting the indirect discharge standard.

[0079] 2、The modified suspended biological filler used in the embodiments of the present application has a rough surface, good hydrophilicity, a porous interior, and a large specific surface area, which can provide a good living environment for the attachment and growth of microorganisms. Crucially, the surface immobilized composite metal component can provide essential trace elements for the growth of microorganisms.

[0080] 3、The filler in the anoxic / aerobic moving bed biofilm system in the embodiments of the present application can present a good fluidized state, which on the one hand increases the contact area between the coking wastewater and the microorganisms, and on the other hand improves the contact efficiency, thereby strengthening the removal effect of nitrogen in the wastewater.

[0081] 4、The anoxic moving bed biofilm system in the embodiments of the present application uses modified suspended biological fillers, which have a faster biofilm formation rate, and the attachment of microorganisms and the interception of the fillers increase the effective biomass in the system, especially the enrichment of high-activity denitrifying bacteria on the fillers, which ensures the stability of the denitrification function, and the strong resistance to water inflow also reduces the water inflow load fluctuation of the subsequent aerobic operation unit.

[0082] 5、The aerobic moving bed biofilm system in the embodiments of the present application uses modified suspended biological fillers, which greatly increase the sludge retention time, realize the attachment and enrichment of low-growth-rate nitrifying bacteria, and stabilize and improve the nitrification function.

[0083] 6、The modified suspended biological fillers of the aerobic moving bed biofilm system in the embodiments of the present application can easily form a good dissolved oxygen gradient environment inside, which can realize the simultaneous nitrification and denitrification process, and further promote the removal of nitrogen.

[0084] 7、The method in the embodiments of the present application has easy control of operation conditions, stable treatment effect, low maintenance cost, and potential for large-scale popularization and application.

[0085] The technical solutions of the present application will be further described in combination with specific embodiments. In the following embodiments, the experimental methods are conventional methods unless otherwise specified. The test materials used in the following embodiments are commercially available from conventional biochemical reagent stores unless otherwise specified.

[0086] Example 1: Screening and matching of composite soluble metal salt components

[0087] Group setting: including 5 test groups, each test group has different metal salt components. In test group 1, the metal salt is Ca 2+ , Mn 2+ , Co 2+ , Mg 2+ and Zn 2+ ; in test group 2, the metal salt is Fe 2+ , Cu 2+ , Co2+ Mg 2+ and Zn 2+ ; in test group 3, the metal salt is Co 2+ Mg 2+ and Zn 2+ ; in test group 4, the metal salt is Fe 2+ Cu 2+ Ca 2+ and Zn 2+ ; in test group 5, the metal salt is Fe 2 + Cu 2+ Ca 2+ Mn 2+ Co 2+ Mg 2+ and Zn 2+ .

[0088] Anoxic experiment process:

[0089] First, the suspended biological filler (for example, polyurethane filler, size 2 cm*2 cm*2 cm) is co-impregnated with different molar ratio metal salt solution (including test group 1, test group 2, test group 3, test group 4 and test group 5) and phosphate buffer solution (molar ratio of Na2HPO4 and KH2PO4 is 0.15:0.20) and dried to obtain modified suspended biological filler. Second, 20 of each modified suspended biological filler are placed in a 1L beaker, 800mL of sludge mixture (concentration of 3g / L) is added to the beaker, and carbon source, nitrogen source and phosphorus source are added according to C:N:P=200:5:1, and the culture is continuously stirred for 10d (microbial biofilm formation process); then, 5 biofilm-formed fillers are taken out and placed in a 500mL beaker, 300mL of substrate solution (COD: 500mg / L, NO3 - : 50mg / L) is prepared, nitrogen is blown to a dissolved oxygen content of less than 0.5mg / L, stirring is started, and NO3 - concentration is measured every 1h, and after the reaction, the sludge amount is measured by constant weight method, and the results are calculated in terms of denitrification rate (SDOR) (mgNO3 - / g MLSS·d).

[0090] Oxygen experiment process:

[0091] First, the suspended biological filler (for example, polyurethane filler, size 2 cm*2 cm*2 cm) is co-impregnated with different molar ratios of metal salt solution (including test group 1, test group 2, test group 3, test group 4 and test group 5), phosphate buffer solution (molar ratio of Na2HPO4 and KH2PO4 is 0.15:0.20) and dried to obtain the modified suspended biological filler. Second, 20 of each modified filler are placed in a 1L beaker, 800mL of sludge mixture (concentration of 3g / L) is added to the beaker, and carbon source and nitrogen source are added according to C:N=100:5, and aerated for 10d (microbial biofilm formation process); then, 5 biofilm-formed fillers are taken out and placed in a 500mL beaker, 300mL of substrate solution (COD:200mg / L, NH4 + :50mg / L) is prepared, the dissolved oxygen content is controlled at 3-5mg / L by aeration, and the NH4 + concentration is measured every 1h, and the sludge amount is measured by constant weight method after the reaction is completed, and the results are calculated in terms of ammonia oxidation rate (SAOR) (mg NH4 + / g MLSS·d).

[0092] Experimental results: as shown in Table 1 below.

[0093] Table 1 Screening and matching results of composite soluble metal salt components

[0094]

[0095]

[0096] Result analysis: as shown in Table 1, the combination of Fe 2+ , Cu 2+ , Ca 2+ , Mn 2+ , Co 2+ , Mg 2+ and Zn 2+ can strengthen the synergistic effect between metal ions Zn 2+ and Cu 2+ . Among them, Zn 2+ , as an important enzyme activator of microorganisms, exists in the active center of the enzyme, can activate carbonic anhydrase and carboxypeptidase A and other enzymes necessary for microbial metabolism, and promote microbial growth and metabolism. At this time, Cu 2+ , as a variable valence metal, has high activity at the site, can improve the electron transfer rate in the oxidation-reduction process, and thus jointly promote the removal of pollutants in wastewater.

[0097] Experimental example 2 Screening of matching ratio of composite soluble metal salt components

[0098] Group setting: the molar ratio of each metal salt in the metal salt composition determined in Example 1 is screened, including 8 test groups, test group 1, test group 2, test group 3, test group 4, test group 5, test group 6, test group 7 and test group 8. Among them, each test group includes Fe 2+ , Cu 2+ , Ca 2+ , Mn 2+ , Co 2+ , Mg 2+ and Zn 2+ metal salt, the difference is that the concentration of the specific metal salt is different. The detailed concentration is described in Table 2.

[0099] Anoxic experiment process:

[0100] First, the suspended biological filler (such as polyurethane filler, size 2cm*2cm*2cm) is immersed with different molar ratio metal salt solution (including test group 1, test group 2, test group 3, test group 4 and test group 5, test group 6, test group 7 and test group 8) and phosphate buffer solution (the molar ratio of Na2HPO4 and KH2PO4 is 0.15:0.20) and dried to obtain modified suspended biological filler. Second, 20 of each modified suspended biological filler is placed in a 1L beaker, 800mL of sludge mixture (concentration 3g / L) is added to the beaker, and carbon source, nitrogen source and phosphorus source are added according to C:N:P=200:5:1, and the culture is continuously stirred for 10d (microbial biofilm formation process); then, 5 biofilm-formed fillers are taken out and placed in a 500mL beaker, 300mL of substrate solution (COD:500mg / L, NO3 - :50mg / L) is prepared, nitrogen is blown off to less than 0.5mg / L of dissolved oxygen content, stirring is started, and NO3 - concentration is measured every 1h, after the reaction is completed, the sludge amount is measured by constant weight method, and the result is calculated as denitrification rate (SDOR) (mgNO3 - / gMLSS·d).

[0101] Aerobic experiment process:

[0102] First, the suspended biological filler (for example, polyurethane filler, size 2 cm*2 cm*2 cm) is co-impregnated with different molar ratios of metal salt solution (including test group 1, test group 2, test group 3, test group 4 and test group 5, test group 6, test group 7 and test group 8), phosphate buffer solution (molar ratio of Na2HPO4 and KH2PO4 is 0.15:0.20) and dried to obtain modified suspended biological filler. Second, 20 of each modified filler are placed in a 1L beaker, 800mL of sludge mixture (concentration of 3g / L) is added to the beaker, and carbon source and nitrogen source are added according to C:N=100:5, and aerated for 10d (microbial biofilm formation process); then, 5 biofilm-formed fillers are taken out and placed in a 500mL beaker, 300mL of substrate solution (COD:200mg / L, NH4 + :50mg / L) is prepared, the dissolved oxygen content is controlled at 3-5mg / L by aeration, and the NH4 + concentration is measured every 1h, and the sludge amount is measured by constant weight method after the reaction is completed, and the results are calculated as ammonia oxidation rate (SAOR) (mg NH4 + / g MLSS·d).

[0103] Test results: as shown in Table 2 below.

[0104] Table 2 Molar ratio screening and collocation results of composite soluble metal salt components

[0105]

[0106] As shown in Table 2, when the molar ratios of Fe 2+ , Cu 2+ , Ca 2+ , Mn 2+ , Co 2+ , Mg 2+ and Zn 2+ are 6.58:4.44:3.15:1.32:0.97:2.50:1.24, the ammonia oxidation rate and denitrification rate are the highest.

[0107] Example 3 Screening of suspended biological filler size

[0108] The groups are set as test group 1, test group 2 and test group 3, and polyurethane filler is used as suspended biological filler. The size of the suspended biological filler in test group 1 can be 1cm*1cm*1cm; the size of the suspended biological filler in test group 2 can be 2cm*2cm*2cm; and the size of the suspended biological filler in test group 3 can be 3cm*3cm*3cm.

[0109] Test method: The ratio of the composite soluble metal salt component screened and determined in Example 2 is used to modify the suspended biological fillers in three test groups respectively to obtain modified suspended biological fillers of corresponding sizes, and continuous operation is carried out in an anoxic-aerobic small test reaction system to mainly investigate the removal capacity of COD, TN and NH4 + -N. The suspended biological filler is polyurethane filler with the structural characteristics of rough surface and internal porosity, and the shape is cubic.

[0110] Among them, the modification of the suspended biological fillers of the three test groups specifically includes:

[0111] The soluble metal salts FeSO4, CuCl2, CaCl2, MnSO4, CoSO4, MgSO4 and ZnSO4 are mixed uniformly to prepare a composite soluble metal salt mixed solution, which is prepared for use, wherein the molar ratio of metal ions is Fe 2+ : Cu 2+ : Ca 2+ : Mn 2+ : Co 2+ : Mg 2 + : Zn 2+ = 6.58:4.44:3.15:1.32:0.97:2.50:1.24, and the mass ratio of FeSO4, CuCl2, CaCl2, MnSO4, CoSO4, MgSO4 and ZnSO4 is 10:6:3.5:2:1.5:3:2.

[0112] Na2HPO4 and KH2PO4 are mixed uniformly to prepare a phosphate buffer solution, which is prepared for use, wherein the molar ratio of Na2HPO4 and KH2PO4 is 0.15:0.20, the mass ratio of Na2HPO4 and KH2PO4 is 2.13:2.72, and the pH value is adjusted to 7.5-8.5 with sodium hydroxide (0.5 mol / L).

[0113] The above polyurethane filler, the prepared composite soluble metal salt mixed solution and the prepared phosphate buffer solution are co-impregnated at a volume ratio of 20%:45%:35%, continuously stirred at room temperature for 24 h, and the polyurethane filler is taken out and dried at 40°C for 20 h.

[0114] Among them, the effective volume of the anoxic moving bed biofilm system (A MBBR ) is 3m 3 , the volume addition ratio of the modified polyurethane filler (V biocarrier :V system ) is 40%, and the total is 1.2m 3 , the top is pre-installed with a stirring device 1, and a stainless steel grid is added at the overflow; the aerobic moving bed biofilm system (OMBBR The effective volume is 6m³. 3 In a volume of 2m 3 and 4m 3 A stainless steel mesh is added at the location, and the total volumetric dosage ratio of the modified polyurethane filler is (V biocarrier :V system ) is 20%, totaling 1.2m 3 2 O MBBR The unit is 0.6m. 3 / unit, bottom pre-set aeration disc 2, towards A MBBR and O MBBR The bottom sludge from the coking plant's sludge thickening tank was inoculated into the equalization tank, controlling the sludge concentration to be 4 ± 0.2 g / L. The coking wastewater in the equalization tank was pumped from A using an electromagnetic metering pump. MBBR Bottom injection for anoxic biological treatment of wastewater, with effluent overflowing into O2. MBBR The wastewater undergoes aerobic biological treatment, and the effluent overflows into the secondary sedimentation tank (effective volume 5m³). 3 The mud and water are separated, and the separated bottom mud is returned to O by a diaphragm pump. MBBR Front end, and O MBBR The final mud-water mixture is returned to A by a diaphragm pump. MBBR At the front end, the reflux ratios are controlled at 150% and 450%, respectively.

[0115] The influent was taken from a coking plant in Shanxi Province, with a COD of 2430±150 mg / L and NH4+. + -N 60±14mg / L, TN 182±23mg / L. Operating load: Phase I 0.4kgCOD / m 3 ·d, Phase II 0.65kgCOD / m 3 ·d, Phase III 0.9kg COD / m 3 ·d.

[0116] Water quality measurements: effluent COD, TN, and NH4 + -N. A MBBR / O MBBR Methods for determining the quality of influent and effluent: COD is determined by the dichromate method (National Standard HJ 828-2017); ammonia nitrogen (NH4) is determined by Nessler's reagent spectrophotometry (National Standard HJ 535-2009). + -N; Determination of total nitrogen (TN) by alkaline potassium persulfate digestion ultraviolet spectrophotometry (National Standard HJ 636-2012).

[0117] Experimental results: as shown in Table 3 and Figures 3a-3c As shown.

[0118] Table 3. Differences in nitrification capacity and total nitrogen removal capacity of polyurethane packing materials of different sizes.

[0119]

[0120]

[0121] Results analysis: As shown in Table 3, when the size of the polyurethane filler is 2cm*2cm*2cm, the COD removal rate, TN removal rate and NH4 + -N removal rate are the highest.

[0122] As Figures 3a-3c shown, the modified filler successfully realizes microbial biofilm formation, and the biofilm formed on the outer layer of the filler under the scouring of bubbles and hydraulic shear force is relatively thin, while the biofilm inside is relatively thick and dark. It can be seen that the filler with a size of 2cm*2cm*2cm has stronger ability to realize simultaneous nitrification and denitrification, and the biofilm thickness is suitable, which is beneficial to oxygen flow, and can avoid the problem of blackening of the filler inside caused by too thick biofilm (for example Figure 3c ), which leads to the inability of oxygen to enter, the formation of a larger anaerobic zone, the reduction of mass transfer efficiency, and the reduction of pollutant degradation efficiency, thereby leading to the reduction of ammonia nitrogen removal rate, which makes the simultaneous nitrification and denitrification have less nitrate substrate, and further affects the total nitrogen removal effect.

[0123] Example 4: Anoxic / aerobic moving bed biofilm combined process for treating actual coking wastewater (water quantity fluctuation)

[0124] Test materials: In this example, the coking wastewater in the adjusting tank of a coking plant in Yuncheng City, Shanxi Province is used, the pH is about 8.9-9.1, the COD is about 2350-2550mg / L, the ammonia nitrogen is about 90-110mg / L, the total nitrogen is about 220-250mg / L, the nitrite nitrogen is about 0.2-0.8mg / L, the nitrate nitrogen is about 0.5-1.5mg / L, and the alkalinity is about 450-600mg / L. It should be noted that the data of wastewater treatment is the effect of long-term stable operation, and a large amount of data has been accumulated, so the average value is calculated to show.

[0125] 1. Preparation of modified suspended biological filler

[0126] The detailed preparation process is shown in Example 3 described above, which will not be repeated here.

[0127] 2. Anoxic / aerobic moving bed biofilm treatment

[0128] As Figure 4 shown, the effective volume of the anoxic moving bed biofilm system (A MBBR ) is 3m 3 , and the volume addition ratio of the modified polyurethane filler is (V biocarrier :V system) for 40%, a total of 1.2 m 3 , top pre-set stirring device 1, overflow added stainless steel grid; effective volume of aerobic moving bed biofilm system (O MBBR ) is 6 m 3 , volume 2 m 3 and 4 m 3 added stainless steel grid, the total volume of modified polyurethane filler is added to (V biocarrier :V system ) for 20%, a total of 1.2 m 3 , divided into 2 O MBBR units for 0.6 m 3 / unit, bottom pre-set aeration disc 2 pipe, respectively inoculated with coking plant sludge concentration tank sludge into A MBBR and O MBBR , control sludge concentration is 4±0.2 g / L. The coking wastewater in the adjustment tank is injected from the bottom of A MBBR by electromagnetic metering pump, and the wastewater is subjected to anoxic biological treatment, and the effluent is overflowed into O MBBR for aerobic biological treatment, and the effluent is overflowed into the secondary sedimentation tank (effective volume 5 m 3 ) for sludge-water separation, and the separated sludge is backflowed to the front end of O MBBR by a diaphragm pump, and the sludge-water mixture at the end of O MBBR is backflowed to the front end of A MBBR by a diaphragm pump, and the control backflow ratio is 150% and 450% respectively. Among them, the influent flow (Q) is 1.44 m 3 / d, 2.16 m 3 / d, 2.88 m 3 / d, 3.6 m 3 / d; the sludge backflow rate is 2.16 m 3 / d, 3.24 m 3 / d, 4.32 m 3 / d, 5.4 m 3 / d; the sludge-water mixture backflow rate is 6.48 m 3 / d, 9.72 m 3 / d, 12.96 m 3 / d, 16.2 m 3 / d; hydraulic retention time (HRT) is 6.25 d, 4.17 d, 3.12 d, 2.5 d respectively.

[0129] 3, A MBBR / O MBBR treatment of influent and effluent water quality determination method:

[0130] The operation load of the pilot reactor was adjusted by adjusting the influent flow rate, the influent and effluent water quality indicators during operation were recorded, and the stability of the system was evaluated by detecting the effluent pH. The A MBBR / O MBBR During operation, after the reactor was stable at each treatment load, it was continuously operated for more than 5 HRT and data were collected, the influent and effluent COD, ammonia nitrogen, total nitrogen were determined, the corresponding removal rates were calculated, the nitrite nitrogen and nitrate nitrogen in the influent and effluent were determined, and the sludge yield was calculated, the nitrogen loss (N2 escape) was accounted, the effluent pH was detected, and the average value of the data was taken.

[0131] COD was determined by dichromate method (national standard HJ 828-2017); ammonia nitrogen was determined by Nash reagent spectrophotometry (national standard HJ 535-2009); total nitrogen was determined by alkaline potassium persulfate digestion ultraviolet spectrophotometry (national standard HJ 636-2012); nitrite nitrogen was determined by spectrophotometry (national standard GB 7493-87); nitrate nitrogen was determined by ultraviolet spectrophotometry (national standard HJ / T 346-2007); pH was determined by pH meter; dissolved oxygen was determined by dissolved oxygen meter; A MBBR / O MBBR treatment load; the removal rate of the treatment was calculated according to formula (2) MBBR / O MBBR treatment was calculated according to formula (3) MBBR / O MBBR treatment was calculated according to formula (3)

[0132] treatment load = C in *Q / V (1) In formula (1): C in : influent COD / total nitrogen concentration (g / L), Q: flow rate (m 3 / d), V: effective volume of reactor (m 3 ).

[0133] removal rate = (C in -C eff ) / C in *100% (2) In formula (2): C in , C eff are respectively A MBBR / O MBBR system influent and effluent COD / ammonia nitrogen / total nitrogen (mg / L).

[0134] nitrogen loss = In TN -Eff NO2- -Eff NO3- -Eff NH4+ -Ass N (3) In formula (3): InTN is the total nitrogen of the influent (mg / L), Eff NO2- and Eff NO3- are the nitrite nitrogen and nitrate nitrogen of the effluent (mg / L), respectively, Ass N is the nitrogen assimilated and consumed during microbial growth (mg / L) (accounted by sludge yield).

[0135] Test results: as shown in Table 4.

[0136] Example 5 Anoxic / aerobic moving bed biofilm combined process for treating actual coking wastewater (water quantity fluctuation)

[0137] 1. The modified suspended biological filler is the same as that in Example 4.

[0138] 2. Anoxic / aerobic moving bed biofilm treatment

[0139] Except that the total volume ratio of the filler of the anoxic moving bed biofilm system (Vbiocarrier:Vsystem) is 45%, the sludge reflux ratio is 120%, and the mixed sludge and water reflux ratio is 450%, the rest is the same as that in Example 1.

[0140] The COD, ammonia nitrogen, total nitrogen, nitrite nitrogen, nitrate nitrogen, sludge yield, and pH of the influent and effluent of the AMBBR / OMBBR are measured, and the measurement results are shown in Table 4.

[0141] Example 6 Anoxic / aerobic moving bed biofilm combined process for treating actual coking wastewater (water quantity fluctuation)

[0142] 1. The modified suspended biological filler is the same as that in Example 4.

[0143] 2. Anoxic / aerobic moving bed biofilm treatment

[0144] Except that the total volume ratio of the filler of the anoxic moving bed biofilm system (Vbiocarrier:Vsystem) is 45%, the total volume ratio of the filler of the aerobic moving bed biofilm system (Vbiocarrier:Vsystem) is 25%, the sludge reflux ratio is 130%, and the mixed sludge and water reflux ratio is 520%, the rest is the same as that in Example 4.

[0145] The COD, ammonia nitrogen, total nitrogen, nitrite nitrogen, nitrate nitrogen, sludge yield, and pH of the influent and effluent of the AMBBR / OMBBR are measured, and the measurement results are shown in Table 4.

[0146] Example 7 Anoxic / aerobic moving bed biofilm combined process for treating actual coking wastewater (water quantity fluctuation)

[0147] 1. The modified suspended biological filler is the same as that in Example 4.

[0148] 2. Anoxic / aerobic moving bed biofilm process

[0149] Except that the total volume ratio of the filler to the system (Vbiocarrier:Vsystem) of the anoxic moving bed biofilm system is 45%, the total volume ratio of the filler to the system (Vbiocarrier:Vsystem) of the aerobic moving bed biofilm system is 30%, the rest is the same as the step of Example 4.

[0150] The COD, ammonia nitrogen, total nitrogen, nitrite nitrogen, nitrate nitrogen, sludge yield, and pH of the influent and effluent of the AMBBR / OMBBR were measured, and the measurement results are shown in Table 4.

[0151] Table 4 A MBBR / O MBBR The measurement results of the effluent quality

[0152]

[0153]

[0154]

[0155] Result analysis: In this example A MBBR / O MBBR It can be operated stably for a long time, and can be operated stably for a long time when the treatment load is 0.4-1.0 kgCOD / m 3 / d, 0.037-0.092 kgTN / m 3 / d, and the highest treatment is 1.0 kgCOD / m 3 / d, 0.092 kgTN / m 3 / d, the COD removal rate is 88.20%; the ammonia nitrogen concentration in the effluent is <2.0 mg / L, which meets the direct discharge standard threshold (15 mg / L), the total nitrogen concentration is <50 mg / L, which meets the indirect discharge standard threshold (50 mg / L), and the daily effluent concentration fluctuation is small. The results have far exceeded the existing engineering system efficiency.

[0156] It can be seen that the "anoxic / aerobic moving bed biofilm system" treatment process in the method of the application effectively resists the influence of the fluctuation of the inflow of coking wastewater on the biological treatment process, the wastewater treatment load is high, and the treatment efficiency has far exceeded the existing engineering system efficiency, allowing the production process to increase the yield and reduce the wastewater treatment cost.

[0157] Comparative Example 1: Anoxic activated sludge / aerobic moving bed biofilm combined process for treating actual coking wastewater (water quantity fluctuation)

[0158] The rest is the same as Example 4, i.e. only the modified suspended biological filler with a total volume ratio (V biocarrier :V system ) of 20% is added to the aerobic tank, and after the anoxic tank and the aerobic tank are inoculated with 4±0.2 g / L of sludge in the sludge concentration tank, the coking wastewater in the conditioning tank is directly continuously injected into the anoxic activated sludge tank (A) with an effective volume of 3 m 3 using an electromagnetic metering pump to carry out A / O MBBR biological treatment, wherein the influent flow rate (Q) is 1.44 m 3 / d, 2.16 m 3 / d, 2.88 m 3 / d, the sludge return flow rate is 2.16 m 3 / d, 3.24 m 3 / d, 4.32 m 3 / d, the sludge-water mixture return flow rate is 6.48 m 3 / d, 9.72 m 3 / d, 12.96 m 3 / d, and the hydraulic retention time (HRT) is 6.25 d, 4.17 d, 3.12 d, respectively; the COD, ammonia nitrogen, total nitrogen, nitrite nitrogen, nitrate nitrogen, sludge yield, and pH of the influent and effluent of A / O MBBR are measured, and the measurement results are shown in Table 5.

[0159] Table 5 Measurement results of the effluent water quality in A / O MBBR of Comparative Example 1

[0160]

[0161]

[0162] Result analysis; the long-term continuous operation experiment results show that the A / O MBBR system can be operated efficiently and stably under the condition that the operating load is ≤0.6 kgCOD / m 3 / d, 0.055 kg TN / m 3 / d (i.e. the influent flow rate is 2.16 m 3 / d, and the retention time is 4.17 d), the COD removal rate is 88.84% under the load of 0.6 kgCOD / m 3 / d, 0.055 kg TN / m 3 / d, the effluent ammonia nitrogen is 2.59 mg / L, which meets the direct discharge standard, the effluent total nitrogen is 48.1 mg / L, which meets the interval discharge standard, and the effluent water quality fluctuates little every day. However, when the influent flow rate increases and the load increases to 0.8 kgCOD / m 3 / d, 0.074 kg TN / m3 Although the ammonia nitrogen of the effluent is low (4.55 mg / L), the total nitrogen of the effluent has increased to 85.3 mg / L, which is far more than the 50 mg / L of the intermediate discharge standard, and at this time the nitrogen removal performance of the system is poor.

[0163] It can be seen by comparison that when treating coking wastewater, the A / O MBBR system has lower treatment efficiency than the A MBBR / O MBBR system in Example 1 when the water inflow is impacted, and the difference in total nitrogen removal rate is particularly obvious, which is due to the difference in the operation process of the anoxic tank. In the method of the present application, the anoxic tank of the A / O MBBR / O MBBR system is added with modified suspended biological fillers, which on the one hand promotes the attachment and growth of denitrification functional bacteria to achieve effective enrichment, and on the other hand, the interception of the fillers also ensures the stable and effective functional bacteria biomass in the anoxic tank, which can still maintain the high-efficiency denitrification performance of the system when the water inflow is impacted. It is worth noting that although the water inflow gradually increases, the ammonia nitrogen removal rate of the A / O MBBR system changes little, that is, the nitrification function is stable.

[0164] When treating coking wastewater with fluctuating water inflow, compared with the method "anoxic / aerobic moving bed biofilm system" of the present application, the "A / O MBBR system" can only be operated at a lower load, and the total nitrogen removal efficiency is also lower.

[0165] Comparative Example 2: Treatment of actual coking wastewater (water inflow fluctuation) by anoxic activated sludge / aerobic activated sludge combined process

[0166] Except that no modified suspended fillers are added in the anoxic tank and the aerobic tank, the rest is the same as Example 1, that is, after the sludge concentration tank sludge of 4±0.2 g / L is inoculated in the anoxic tank and the aerobic tank, the coking wastewater of the adjusting tank is directly continuously injected into the anoxic activated sludge tank (A) by an electromagnetic metering pump for A / O biological treatment, wherein the water inflow (Q) is 1.44 m 3 / d, 2.16 m 3 / d, 2.88 m 3 / d, the sludge reflux flow is 2.16 m 3 / d, 3.24 m 3 / d, 4.32 m 3 / d, the sludge-water mixture reflux flow is 6.48 m 3 / d, 9.72 m 3 / d, 12.96 m 3 / d, the hydraulic retention time (HRT) was 6.25d, 4.17d, and 3.12d, respectively; COD, ammonia nitrogen, total nitrogen, nitrite nitrogen, nitrate nitrogen, sludge production and pH of A / O influent and effluent were measured, and the results are shown in Table 6.

[0167] Table 6. Results of A / O effluent water quality measurement in Comparative Example 2

[0168]

[0169]

[0170] Long-term continuous operation experiments show that the A / O system can operate under loads ≤0.4 kg COD / m³. 3 / d, 0.037kgTN / m 3 / d (i.e., influent flow rate is 1.44m) 3 Under conditions of 6.25 days and a residence time of 0.4 kg COD / m³, it can operate efficiently and stably. 3 / d, 0.037kg TN / m 3 At a load of 0.6 kg COD / m³, the COD removal rate reached 89.96%, the effluent ammonia nitrogen was 1.78 mg / L, meeting the direct discharge standard, and the effluent total nitrogen was 44.1 mg / L, meeting the indirect discharge standard. The daily effluent water quality showed little fluctuation. However, when the influent flow increased and the load rose to 0.6 kg COD / m³, the removal rate decreased. 3 / d, 0.055kg TN / m 3 At a rate of / d, the effluent ammonia nitrogen increased to 11.56 mg / L, and the total nitrogen in the effluent had increased to 78.6 mg / L. Simultaneously, nitrite nitrogen began to accumulate in the effluent (5.56 mg / L), at which point the system's nitrogen removal performance began to deteriorate; finally, the load was increased to 0.8 kg COD / m³. 3 / d, 0.074kg TN / m 3 When the nitrogen concentration in the effluent increased to 35.42 mg / L and the total nitrogen concentration increased to 135.3 mg / L, both far exceeding the thresholds specified in the indirect discharge standards. At this point, the nitrogen removal function of the system was almost completely destroyed.

[0171] Compare A / O in Example 1 MBBR During continuous operation, the A / O system showed a significant decrease in ammonia nitrogen and total nitrogen removal efficiency during influent flow shocks, which can be attributed to the different operating processes of the aerobic tank. The first step is to analyze the differences in ammonia nitrogen removal between the A / O and aerobic tanks. MBBRThe aerobic tank of the system is added with modified suspended biological filler, which promotes the attached growth of autotrophic nitrifying bacteria with low growth rate and achieves significant enrichment. On the other hand, the interception effect of the filler also ensures the stable and effective functional bacteria biomass in the aerobic tank, which can still stably exert the nitrification function when the water quantity is impacted. Secondly, the difference in total nitrogen removal is analyzed, and the A / O MBBR The modified suspended biological filler in the aerobic tank of the system is a porous structure, and after the microorganisms form a biofilm, the outer layer of the biofilm is aerobic and the inner layer is anoxic, and the products of ammonia oxidation, nitrite nitrogen and nitrate nitrogen, can be directly reduced to nitrogen by denitrification, realizing simultaneous nitrification and denitrification.

[0172] When treating coking wastewater with fluctuating water quantity, compared with the "anoxic / aerobic moving bed biofilm system" method of the present application, the "A / O system" can only operate at a lower load, and the nitrification performance and total nitrogen removal efficiency are also lower.

[0173] Example 8: Treatment of actual coking wastewater (water quality fluctuation) by anoxic / aerobic moving bed biofilm combined process

[0174] In this example, the coking wastewater in the regulating tank of a coking plant in Yuncheng City, Shanxi Province was used, with pH about 8.8-9.5, COD about 1900-5700 mg / L, ammonia nitrogen about 80-210 mg / L, total nitrogen about 170-450 mg / L, nitrite nitrogen about 0.5-1.6 mg / L, nitrate nitrogen about 0.5-3.5 mg / L, and alkalinity about 380-930 mg / L. It should be noted that the data of wastewater treatment is the effect of long-term stable operation, and a large amount of data has been accumulated, so the average value is calculated to show.

[0175] 1. The modified suspended biological filler is the same as step 1 of Example 4.

[0176] 2. Anoxic / aerobic moving bed biofilm treatment

[0177] The effective volume of the anoxic moving bed biofilm system (A MBBR ) is 3m 3 , the volume addition ratio of the modified polyurethane filler (V biocarrier :V system ) is 40%, a total of 1.2m 3 , a stirring device 1 is pre-installed at the top, and stainless steel grids are added at the overflow; the effective volume of the aerobic moving bed biofilm system (O MBBR ) is 6m 3 , stainless steel grids are added at the volumes of 2m 3 and 4m 3 , and the volume addition ratio of the modified polyurethane filler (V biocarrier :Vsystem ) is 25%, total 1.5m 3 , equally divided into 2 O MBBR units is 0.75m 3 / unit, bottom pre-set aeration disc 2 pipes, respectively inoculated into A MBBR and O MBBR the bottom sludge concentration of coking sludge concentration tank, control sludge concentration is 4±0.3g / L. The coking wastewater of adjusting pool is injected from the bottom of A MBBR , the wastewater is subjected to anoxic biological treatment, and the effluent is overflowed into O MBBR to carry out aerobic biological treatment, and the effluent is overflowed into the secondary sedimentation tank (effective volume 5m 3 ) to separate the sludge and water, and the separated sludge is returned to the front end of O MBBR by a diaphragm pump, and the sludge-water mixture at the end of O MBBR is returned to the front end of A MBBR by a diaphragm pump, and the return ratio is controlled to be 150% and 450% respectively. Among them, the influent flow rate (Q) is 1.44m 3 / d; the sludge return flow rate is 2.16m 3 / d; the sludge-water mixture return flow rate is 6.48m 3 / d; the hydraulic retention time (HRT) is 6.25d respectively.

[0178] A MBBR / O MBBR treatment, the determination method of the influent and effluent water quality is the same as that of example 4, and the determination results are shown in table 7.

[0179] Example 9: anoxic / aerobic moving bed biofilm combined process for treating actual coking wastewater (water quality fluctuation)

[0180] 1. The modified suspended biological filler is the same as that of step 1 of example 8.

[0181] 2. Anoxic / aerobic moving bed biofilm treatment

[0182] Except that the total volume ratio (V biocarrier :V system ) of the filler of the anoxic moving bed biofilm system is 45%; the sludge return ratio is 120%, and the sludge-water mixture return ratio is 450%, the rest is the same as that of example 2.

[0183] The COD, ammonia nitrogen, total nitrogen, nitrite nitrogen, nitrate nitrogen, sludge yield and pH of the influent and effluent of A MBBR / O MBBR are determined, and the determination results are shown in table 7.

[0184] Example 10: anoxic / aerobic moving bed biofilm combined process for treating actual coking wastewater (water quality fluctuation)

[0185] 1. The modified suspended biological media is the same as step 1 of Example 8.

[0186] 2. Anoxic / aerobic moving bed biofilm process

[0187] Except that the total volume ratio of the media filling (V biocarrier :V system ) of the anoxic moving bed biofilm system is 45%, the total volume ratio of the media filling (V biocarrier :V system ) of the aerobic moving bed biofilm system is 25%, the sludge reflux ratio is 130%, and the sludge-water mixture reflux ratio is 520%, the rest is the same as step of Example 2.

[0188] Determination A MBBR / O MBBR The COD, ammonia nitrogen, total nitrogen, nitrite nitrogen, nitrate nitrogen, sludge yield, and pH of the influent and effluent are determined, and the determination results are shown in Table 7.

[0189] Example 11: Anoxic / aerobic moving bed biofilm combined process for treating actual coking wastewater (water quality fluctuation)

[0190] 1. The modified suspended biological media is the same as step 1 of Example 8.

[0191] 2. Anoxic / aerobic moving bed biofilm process

[0192] Except that the total volume ratio of the media filling (V biocarrier :V system ) of the anoxic moving bed biofilm system is 45%, the total volume ratio of the media filling (V biocarrier :V system ) of the aerobic moving bed biofilm system is 30%, the rest is the same as step of Example 8.

[0193] Determination A MBBR / O MBBR The COD, ammonia nitrogen, total nitrogen, nitrite nitrogen, nitrate nitrogen, sludge yield, and pH of the influent and effluent are determined, and the determination results are shown in Table 7.

[0194] Table 7 Determination results of effluent water quality in Examples 8-11 A MBBR / O MBBR

[0195]

[0196]

[0197] ​The change of the influent water quality correspondingly changes the operation load of the pilot reactor. The influent and effluent water quality indexes during the operation are recorded, and the stability of the system is evaluated through the detection result of the effluent pH. The A / O moving bed biofilm system in the method of the present application MBBR / O MBBR During the operation, after the reactor is stabilized at each treatment load, the operation is continued for more than 5 HRT, and the data are collected. The influent and effluent COD, ammonia nitrogen, and total nitrogen are measured, the corresponding removal rates are calculated, the nitrite nitrogen and nitrate nitrogen in the influent and effluent are measured, the sludge yield is measured, the nitrogen loss (N2 escape) is calculated, and the effluent pH is detected. The average value of the data is taken. The measurement results show that: in the present embodiment, the A / O moving bed biofilm system in the method of the present application MBBR / O MBBR can be operated stably for a long time, and can be operated stably for a long time when the treatment load is 0.328-0.904 kgCOD / m 3 / d and 0.029-0.071 kgTN / m 3 / d. When the highest treatment is 0.904 kgCOD / m 3 / d and 0.071 kgTN / m 3 / d, the COD removal rate reaches 88.28%; the ammonia nitrogen concentration in the effluent is <3.0 mg / L, which meets the direct discharge standard threshold (15 mg / L), the total nitrogen concentration is <50 mg / L, which meets the indirect discharge standard threshold (50 mg / L), and the daily effluent concentration fluctuation is small. The results have far exceeded the existing engineering system efficiency.

[0198] It can be seen that the treatment process of the "anoxic / aerobic moving bed biofilm system" in the method of the present application effectively resists the influence of the fluctuation of the influent water quality of the coking wastewater on the biological treatment process, the wastewater treatment load is high, the treatment efficiency has far exceeded the existing engineering system efficiency, the production process is allowed to increase the yield, and the wastewater treatment cost is reduced.

[0199] Comparative Example 3: Anoxic activated sludge / aerobic activated sludge combined process for treating actual coking wastewater (water quality fluctuation)

[0200] Except that no modified suspended filler is added in the anoxic tank and the aerobic tank, the rest is the same as Example 8, that is, after the sludge concentration tank sludge of 4±0.2 g / L is inoculated in the anoxic tank and the aerobic tank, the coking wastewater of the adjusting tank is directly continuously injected into the anoxic activated sludge tank (A) by using an electromagnetic metering pump for A / O biological treatment, wherein the influent flow rate (Q) is 1.44 m 3 / d, the sludge reflux flow rate is 2.16 m 3 / d, and the sludge-water mixture reflux flow rate is 6.48 m 3 / d, hydraulic retention time (HRT) was 6.25d; COD, ammonia nitrogen, total nitrogen, nitrite nitrogen, nitrate nitrogen, sludge production and pH of A / O influent and effluent were measured, and the results are shown in Table 8.

[0201] Table 8. Results of A / O effluent water quality determination in Comparative Example 3

[0202] Treatment load (kgCOD / m 3 / d) 0.328 0.469 0.678 0.904 Treatment load (kg TN / m 3 / d) 0.029 0.044 0.058 0.071 Influent COD (mg / L) 2050 3100 4240 5650 Effluent COD (mg / L) 197 323 478 695 COD removal rate (%) 90.39％ 89.58％ 88.72％ 88.70％ Influent total nitrogen (mg / L) 180 276 365 445 Effluent total nitrogen (mg / L) 23.6 47.8 155.6 248.3 Total nitrogen removal rate (%) 86.89％ 82.68％ 57.37％ 44.20％ Influent ammonia nitrogen (mg / L) 80 145 182 202 Effluent ammonia nitrogen (mg / L) 1.26 5.34 37.55 85.23 Ammonia nitrogen removal rate (%) 98.42％ 96.31％ 79.36％ 57.81％ Nitrogen assimilation consumption (mg / L) 47.56 118.72 200.24 251.30 Effluent nitrite nitrogen (mg / L) 1.21 2.55 16.41 30.24 Effluent nitrate nitrogen (mg / L) 6.8 28.7 56.2 55.12 Nitrogen loss (mg / L) 123.17 120.69 54.6 23.11 Effluent pH 7.75 7.74 7.81 7.81

[0203] Long-term continuous operation experiments show that the A / O system can operate under loads ≤0.469 kg COD / m³. 3 / d, 0.044kgTN / m 3 Under conditions of / d (i.e., influent COD of 3100 mg / L and TN of 276 mg / L), it can operate efficiently and stably at 0.469 kg COD / m³. 3 / d, 0.044kg TN / m 3 At a load of 0.678 kg COD / m³, the COD removal rate reached 89.58%, the effluent ammonia nitrogen was 5.34 mg / L, meeting the direct discharge standard, and the effluent total nitrogen was 47.8 mg / L, meeting the intermittent discharge standard. The daily effluent water quality fluctuation was minimal. However, when the influent water quality changed (COD and TN concentrations increased), the load increased to 0.678 kg COD / m³. 3 / d, 0.058kg TN / m 3 At a certain point, the effluent ammonia nitrogen increased to 37.55 mg / L, and the total nitrogen increased to 85.23 mg / L, exceeding the intermittent discharge standard threshold. Simultaneously, the effluent nitrite nitrogen accumulated to 16.41 mg / L. At this point, both the ammonia oxidation and nitrification processes in the system were inhibited. Finally, the load increased to 0.904 kg COD / m³. 3 / d, 0.071kg TN / m 3 At / d, the ammonia nitrogen and total nitrogen in the effluent continued to increase and far exceeded the thresholds specified in the indirect discharge standards.

[0204] Comparative Example 8, A MBBR / O MBBR During continuous operation, the A / O system showed a significant decrease in the removal efficiency of both ammonia nitrogen and total nitrogen during influent water quality shocks. Analysis of the reasons: Firstly, an analysis of the differences in ammonia nitrogen removal... MBBR / O MBBR The aerobic tank of the system, due to the addition of modified suspended biological packing material, not only promoted the attachment and growth of low-growth-rate autotrophic nitrifying bacteria and achieved significant enrichment, but also ensured a stable and effective biomass of functional bacteria within the aerobic tank through the retention effect of the packing material, allowing it to maintain stable nitrification function even under water quality shocks. Secondly, the differential analysis of total nitrogen removal was conducted, A... MBBR / O MBBRThe modified suspended biological filler is added in the anoxic tank of the system, which promotes the attachment and growth of denitrifying functional bacteria and enriches them. In addition, the interception of the filler ensures the stable and effective biomass of functional bacteria in the anoxic tank, and the system can still maintain high denitrification performance when the water quality is impacted. Furthermore, the dissolved oxygen gradient environment formed inside the filler of the system also promotes the realization of simultaneous nitrification and denitrification. MBBR / O MBBR The dissolved oxygen gradient environment formed inside the filler of the system also promotes the realization of simultaneous nitrification and denitrification.

[0205] When treating coking wastewater with fluctuating influent water quality, the A / O system can only operate at a lower influent pollutant concentration compared with the anoxic / aerobic moving bed biofilm system of the method of the present application, and the nitrification performance and total nitrogen removal efficiency are also lower.

[0206] Those skilled in the art should understand that the above discussion of any embodiment is only exemplary and is not intended to imply that the scope of the present disclosure (including the claims) is limited to these examples; under the idea of the present disclosure, the technical features in the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other changes of different aspects of the embodiments of the present disclosure as described above. In order to be brief, they are not provided in details.

[0207] Although the present disclosure has been described in conjunction with specific embodiments thereof, many alternatives, modifications and variations will be apparent to those skilled in the art from the foregoing description.

[0208] The embodiments of the present disclosure are intended to cover all such alternatives, modifications and variations which fall within the broad scope of the appended claims. Accordingly, any omission, modification, equivalent replacement, improvement, etc. made within the spirit and principle of the embodiments of the present disclosure should be included in the protection scope of the present disclosure.

Claims

1. A process for enhanced removal of nitrogen in industrial wastewater, characterized in that, The system comprises: Providing an industrial wastewater nitrogen removal system, comprising an anoxic moving bed biofilm system, an aerobic moving bed biofilm system and a secondary sedimentation tank arranged in series; Providing a modified suspended biological filler with a preset size; the modified suspended biological filler comprises a polyurethane filler impregnated with a composite soluble metal salt; the composite soluble metal salt comprises iron salt, copper salt, calcium salt, manganese salt, cobalt salt, magnesium salt and zinc salt; The modified suspended biological filler is added to a first preset area in the anoxic moving bed biofilm system and a second preset area in the aerobic moving bed biofilm system, respectively; The industrial wastewater is fed into the industrial wastewater nitrogen removal system, and subjected to anoxic biological treatment in the anoxic moving bed biofilm system and aerobic treatment in the aerobic moving bed biofilm system; The method for providing a modified suspended biological filler with a preset size comprises: The soluble iron salt, the soluble copper salt, the soluble calcium salt, the soluble manganese salt, the soluble cobalt salt, the soluble magnesium salt and the soluble zinc salt are configured as a composite soluble metal salt mixed solution; wherein the molar ratio of the soluble iron salt, the soluble copper salt, the soluble calcium salt, the soluble manganese salt, the soluble cobalt salt, the soluble magnesium salt and the soluble zinc salt is (1.64-32.89):(0.74-22.22):(0.45-22.52):(0.26-9.94):(0.32-6.45):(0.42-16.67):(0.25-12.42); Providing a phosphate buffer solution with a concentration of 0.05-0.5 mol / L and a pH of 7.5-8.5; The polyurethane foam with a preset size, the composite soluble metal salt mixed solution and the phosphate buffer solution are impregnated, stirred and mixed, and then dried to obtain the modified suspended biological filler; wherein the mixing volume ratio of the polyurethane filler, the composite soluble metal salt mixed solution and the phosphate buffer solution is (20%-30%):(40%-60%):(30%-50%).

2. The process for enhanced removal of nitrogen in industrial wastewater according to claim 1, characterized in that, The concentration of the phosphate buffer solution is 0.2-0.35 mol / L; the mixing volume ratio of the polyurethane filler, the composite soluble metal salt mixed solution and the phosphate buffer solution is (20%-25%):(40%-45%):(35%-40%); the concentration of the phosphate buffer solution is 0.2-0.35 mol / L.

3. The process for enhanced removal of nitrogen from industrial wastewater according to claim 1, wherein, The impregnation and stirring mixing comprises: an impregnation and stirring temperature of 20-40°C and an impregnation and stirring time of 15-30h; the drying temperature is 30-45°C and the drying time is 10-15h.

4. The process for enhanced removal of nitrogen from industrial wastewater according to claim 1, wherein, The volume ratio of the modified suspended biological filler to the anoxic moving bed biofilm system is 35%-50%; The volume ratio of the modified suspended biological filler to the aerobic moving bed biofilm system is 15%-40%.

5. The process for enhanced removal of nitrogen from industrial wastewater according to claim 4, wherein, The volume ratio of the modified suspended biological filler to the anoxic moving bed biofilm system is 40%-45%; The volume ratio of the modified suspended biological filler to the anoxic moving bed biofilm system is 20%-25%.

6. The process for enhanced removal of nitrogen species from industrial wastewater according to claim 4, wherein, The aerobic moving bed biofilm system comprises a plurality of aerobic units arranged in series, and the modified suspended biological filler is uniformly distributed in the plurality of aerobic units. In the aerobic unit, the dissolved oxygen concentration in the second preset area is 4-5 mg / L, and the dissolved oxygen concentration in other areas is 2-3 mg / L.

7. The process for enhanced removal of nitrogen species from industrial wastewater according to claim 6, wherein, A first screen is arranged at the overflow weir of the anoxic moving bed biofilm system, and a second screen is arranged in each of the plurality of aerobic units; at the position of the second screen, the pool width: pool length of the aerobic moving bed biofilm system is 1:1-1:2.5; the width of the second screen is 1-1.5 cm; and the ratio of the volume of the aerobic unit except the second screen to the total volume of the aerobic unit is 1:2-1:1.

25.

8. The process for enhanced removal of nitrogen in industrial wastewater according to claim 1, wherein the industrial wastewater is selected from coking wastewater, amino acid production wastewater, pharmaceutical wastewater, dyeing wastewater, or coal gasification wastewater; and the nitrogen includes at least one of nitrogen-containing heterocyclic compounds, ammonia nitrogen, cyanide, and thiocyanate. The flow rate of the sludge-water mixture at the end of the aerobic moving bed biofilm system backflowing to the front end of the anoxic moving bed biofilm system is 250%-550% of the industrial wastewater inflow, and the flow rate of the sludge in the secondary sedimentation tank backflowing to the front end of the aerobic moving bed biofilm system is 100%-180% of the industrial wastewater inflow.

9. The process for enhanced removal of nitrogen species from industrial wastewater according to claim 1, wherein, The industrial wastewater is selected from coking wastewater, amino acid production wastewater, pharmaceutical wastewater, dyeing wastewater, or coal gasification wastewater; and the nitrogen includes at least one of nitrogen-containing heterocyclic compounds, ammonia nitrogen, cyanide, and thiocyanate.

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