Integrated process of double physical-chemical coupling O / H / H / O for treating typical industrial wastewater and application

Abstract

A double physical-chemical coupling O / H / H / O integrated process for treating typical industrial wastewater and its application. The process includes a double physical-chemical unit composed of front and rear physical-chemical units, carbon and ammonia oxidation unit O1, hydrolysis and denitrification path selection units H1 and H2, and complete nitrification unit O2. The O1 and O2 aerobic units adopt in-situ sludge separation biological three-phase fluidized bed reactors, which have the characteristics of stable operation at high load, and the H1 and H2 units include a multifunctional combined arrangement coupling reactor of anaerobic ammonia oxidation, autotrophic denitrification and heterotrophic denitrification, combined with underwater plug flow mixing and sludge stratification and quality suspension principles, to realize complete removal of total nitrogen in wastewater. The process can completely oxidize organic pollutants in coking wastewater, including refractory components, while regulating the fate of heavy metals, greatly reducing the energy consumption and material consumption of the system operation, obtaining high-quality treated effluent, and after deep treatment, reaching the standard of circulating cooling water reuse.

Description

Technical Field

[0001] This invention pertains to a typical industrial wastewater treatment process system. The invention relates to the following principles: wastewater treatment process principles; fluidized bed enhanced mixing principle; in-situ gas-liquid-solid separation principle using a three-phase separator; independent sludge system combined control principle; functional unit microbial domestication and enrichment principle; engineering application principle of process control driving characteristic microbial expression; material separation principle of pre- and post-process physicochemical units; combined control principle of diversified processes; biochemical degradation principle of toxic, high-nitrogen industrial wastewater; aerobic biological oxidation principle of high-load, recalcitrant organic matter; low-energy, low-material-consumption internal and external carbon source control and energy distribution principle; multi-component, multi-type total nitrogen normalization principle; multi-pathway biological denitrification mode with self-sufficient internal carbon source; low-energy denitrification principle driven by short-cut nitrification + anaerobic ammonium oxidation; engineering application of efficient simultaneous carbon and nitrogen removal dual physicochemical coupling O / H / H / O integrated process; and engineering modification application schemes based on existing processes. The technology based on the above principles complements and improves the shortcomings of the A / A / O process in that it cannot completely remove nitrogen and cannot reasonably match the relationship between carbon source and microbial functional requirements. It demonstrates the coupled and synergistic relationship between multi-pathway nitrogen removal and carbon removal. Therefore, it is applicable to future water treatment technology applications with more stringent emission requirements and to the upgrading and transformation of existing A / A / O process technologies. Background Technology

[0002] Since its inception in 1914 by Ardefn and Lockett, the activated sludge process for wastewater treatment remains the most widely used biological treatment technology. Through numerous trials and improvements, many variations of the activated sludge process are now in use. A typical treatment process consists of aeration units, an air supply system, a sludge settling tank, and a sludge return system. Due to the recalcitrant biodegradability of coking wastewater, a two-stage biological aeration activated sludge process was once widely used. This process effectively removes pollutants such as phenols and cyanides from coking wastewater, but its removal efficiency for ammonia nitrogen is relatively poor, resulting in poor effluent quality. With concentrations around 200 mg / L or even higher, and COD around 500 mg / L, this method is rarely used nowadays. This is due to the high concentrations of ammonia nitrogen and total nitrogen in coking wastewater, especially the presence of bound nitrogen (CN), which is difficult to remove. – / SCN – Biological nitrogen removal processes, such as those using pyridine / quinoline, are crucial for wastewater treatment. Traditional activated sludge processes have low ammonia nitrogen removal rates, making the selection of biological nitrogen removal technologies a key aspect of wastewater treatment engineering. Currently used processes include A / O, A / A / O, and A / O / O processes.

[0003] A / O (anoxic-oxic) process is currently the most widely used in coking wastewater treatment, which is a pre-denitrification process. The anoxic tank carries out denitrification reaction, and the aerobic tank carries out nitrification reaction. The anoxic section of A / O process generally adopts biofilm method, and the aerobic section adopts plug flow activated sludge method. Aerobic carbon oxidation and nitrification reaction are completed in the same plug flow reactor, and alkalinity required for nitrification reaction is added in the influent. Due to the small dilution function of this plug flow tank to toxic and harmful organic matter, the system has weak impact resistance, especially the nitrifying bacteria are very sensitive, and are easily poisoned by phenol, cyanide (CN – ), thiocyanate (SCN – ), sulfide (S 2– ) and the like. As shown in the existing research, 0.5 mg / L of phenol has inhibitory effect on nitrifying bacteria. At the same time, due to the competition between carbon-oxidizing heterotrophic bacteria and nitrifying autotrophic bacteria in the aerobic reaction tank, when the content of organic matter is high and the population of nitrifying autotrophic bacteria is small, nitrification is inhibited, and it is difficult to completely nitrify. Therefore, a large amount of water must be added for dilution in the aerobic tank during operation (generally the dilution ratio is 100%, and the dilution water is added in the form of defoaming water) to reduce the concentration of organic matter or other toxic substances, so as to eliminate the inhibition on nitrifying bacteria, and to improve the nitrification effect by prolonging the hydraulic retention time and increasing the dissolved oxygen. Due to the high organic load in the aerobic section, it is not conducive to the growth of nitrifying autotrophic bacteria, and the activated sludge system has low bacteria holding capacity. In actual operation, only by means of high sludge return ratio can the high sludge concentration in the aerobic tank be maintained, so as to maintain a certain amount of nitrifying bacteria. Therefore, the aeration intensity of the aerobic section is high, the fluid field is unstable, the hydraulic retention time is long, and the sludge return amount is large, resulting in high energy consumption. At the same time, the process operation can only maintain complete nitrification reaction to obtain high ammonia nitrogen removal rate, so that the alkali consumption is also high. The operation cost is very high, and the cost per ton of water treatment is more than 10 yuan. The A / O design is based on the concept of strengthening organic matter and ammonia nitrogen removal, and focuses on strengthening biological aerobic reaction, and only takes denitrification as a denitrification reaction, ignoring the important role of denitrification reaction in coking wastewater treatment, so that the anoxic reaction time is not designed enough, the denitrification efficiency is usually less than 50%, the total nitrogen removal rate is not high, and the organic matter removal rate is less than 20%, so that the organic load of the aerobic section is large and fluctuates greatly, which easily causes load impact, especially the removal rate of refractory organic matter in this system is very low. Therefore, even if the influent is diluted at a dilution ratio of 100%, the effluent COD is still higher than 300 mg / L, and the color is high. Moreover, the system has weak impact resistance. Therefore, the currently operated A / O process has weak impact resistance, high cost, large amount of dilution water, and the COD and color of the effluent are seriously over-standard, which is difficult to meet the increasingly strict environmental protection requirements. The double return of mixed liquor and sludge causes huge energy consumption, the addition of dilution water also consumes cost, the sludge separation effect is not good, the oxygen utilization rate is not high, and if the raw water is not diluted, the biological effluent COD is greater than 500 mg / L.

[0004] Based on the problem that the refractory organic matters in coking wastewater are difficult to be degraded by aerobic process, anaerobic hydrolysis is added before anoxic denitrification to make some heterocyclic and polycyclic organic compounds to be degraded by ring-opening. A / A / O (anaerobic / anoxic / aerobic) biological nitrogen removal process is developed, and the total hydraulic retention time (HRT) is greater than 150 h. The design idea is that the anaerobic retention time is 10-30 h to control the hydrolysis in the hydrolysis section and prevent too much removal of the easily and refractory organic matters. The research and engineering operation results have proved that the A / A / O process is slightly better than the A / O process in terms of the resistance to organic matter shock, but there is no significant difference in the total removal rate of organic matter and ammonia nitrogen between the two processes. The problems in the A / O process also exist in the A / A / O process. Since the A / A / O process is operated by single sludge method, the distribution of the sludge residence time in the three reactors and the functional conversion / adaptation greatly challenge the function of the microorganisms, which easily causes local over-concentration of the sludge and confusion of the metabolic functions. The statistical data show that the role of the first A reactor in the coking wastewater A / A / O process is limited, and it almost does not remove COD and does not improve the B / C value of the wastewater, but only plays a dilution and buffering role. Therefore, compared with the A / O process, the A / A / O process does not show obvious technical progress in the newly constructed biological nitrogen removal process.

[0005] Based on the fact that the power consumption and alkali consumption of the aforementioned A / O, A / A / O and other complete nitrification processes are relatively large, the short-cut nitrification and denitrification process is favored by researchers. From the demand of denitrification, it is redundant to oxidize nitrite to nitrate, and the ammonia oxidation can be controlled to the nitrite stage, which can save the consumption of dissolved oxygen and alkali. Studies have shown that the concentration of organic matter, the type and concentration of toxic inhibitors, temperature, DO, pH and free ammonia concentration are the main factors affecting the relative activity of ammonia oxidation and nitrite oxidation bacteria. Based on this principle, the A / O / O (anoxic / aerobic / aerobic) process characterized by short-cut nitrification and denitrification is developed, and the total hydraulic retention time (HRT) is greater than 200 h. The initial operation shows that the unit cost of this short-cut process can be reduced to 8 yuan / ton, but after a long-term operation, the short-cut nitrification gradually changes to complete nitrification. At present, the control of short-cut nitrification is based on constant parameters (such as lower dissolved oxygen, sludge age, organic load, relatively high pH or inhibitors, etc.), and time control strategy is adopted to achieve short-cut nitrification. Due to the volatility of the coking wastewater quality, the lower dissolved oxygen control method is contradictory to the higher ammonia removal rate, and in order to maintain a high ammonia removal rate, a longer hydraulic retention time is necessary. The high pH and inhibitor control also has problems. Although the short-cut nitrification is dominant at the beginning, when the nitrifying bacteria gradually adapt to the higher pH and inhibitors, complete nitrification reaction will gradually dominate, so the system cannot stably maintain short-cut nitrification and denitrification. Therefore, the A / O / O process cannot maintain stable short-cut nitrification and denitrification, and after a period of operation, it gradually changes to complete nitrification and denitrification process.

[0006] A / A / O / O (anaerobic-anoxic-oxic-oxic) process is still a complete nitrification and denitrification process, and the total hydraulic retention time (HRT) is greater than 200 h. Considering the different dominant growth environment factors of carbon-oxidizing bacteria and nitrifying bacteria, COD degradation and ammonia oxidation nitrification are realized in two different oxic tanks, and the impact resistance of the system is relatively improved compared with the traditional A / O process. However, the process adopts complete nitrification reaction, and the aeration intensity is large, the hydraulic retention time is long, the sludge return flow is large, and it is difficult to maintain the sludge concentration in each unit reactor, which makes the energy consumption high. At the same time, the process operation can only maintain complete nitrification reaction to obtain high ammonia nitrogen removal rate, which makes the alkali consumption also high, and the cost is very high. Due to the increase of process units, the operation difficulty is increased.

[0007] Through the research on the above process, we found that the current mainstream biological process (mainly A / A / O) has the following common problems, including:

[0008] (1) The removal rate of all A sections to toxic and refractory organic matter is very low. If the influent COD concentration exceeds 1500 mg / L, and the organic load exceeds 0.8 kg COD / (m 3 ·d), the toxicity inhibition is obvious, the COD removal rate of anaerobic A section is less than 10%, which causes the waste of construction and brings serious load impact to the subsequent nitrification process;

[0009] (2) Especially for coking wastewater and other phosphorus-lacking and toxic inhibition industrial wastewater, the A reactor cannot produce methane and other useful resources without phosphorus removal;

[0010] (3) There are many toxic pollutants in the O section that inhibit nitrifying bacteria, and there is a competition between carbon oxidation and ammonia nitrification in space, and there is a priority relationship in electron donor activity (O2 as electron acceptor), which often leads to low nitrification efficiency in O section, incomplete denitrification, and even ammonia nitrogen exceeding standard, which cannot completely remove total nitrogen in principle;

[0011] (4) Sludge return and nitrification liquid return lead to high weir load, more floating sludge in the secondary sedimentation tank, large amount of sludge loss, metabolic disorder of microorganisms, collapse of denitrification function, switching of microorganism function in activated sludge after return, consumption of a large amount of carbon source, dilution effect of return reducing substrate concentration and reaction rate, and high DO caused by return inhibiting denitrification;

[0012] (5) Single sludge system inevitably leads to single denitrification path, and such process relying on sludge return is difficult to edit the reasonable correlation between microbial function and wastewater solution properties, and cannot realize the stability of the system. Especially, the proliferation cycle difference between autotrophic nitrifying bacteria and heterotrophic denitrifying bacteria leads to the loss of autotrophic nitrifying bacteria, which is difficult to ensure the long-term stability of engineering operation;

[0013] (6) Sludge and nitrification liquid reflux is necessary, so that each unit and facility always performs mechanical operation, lack of feasibility of process editing, difficult to reasonably control according to actual water quality, insufficient to change the composition of complex industrial wastewater.

[0014] In summary, the traditional A / A / O process needs to ensure successful nitrification and large reflux ratio to effectively remove nitrogen, but the reflux limits the complete and efficient removal of high-concentration total nitrogen, and it is difficult to achieve the goal of zero total nitrogen concentration in actual engineering. Therefore, for the treatment of industrial wastewater with high toxicity, high nitrogen and high C / N ratio, new water treatment processes and new process theories must be developed, although the A / A / O process technology is widely used in domestic sewage treatment, but based on the above characteristics of industrial wastewater, it is necessary to rethink and seek a new process with low energy consumption and low material consumption with the goal of zero total nitrogen concentration. SUMMARY

[0015] In view of the above problems, the present application proposes a fluidized bed-based pre-oxidation-aerobic carbon removal (partial ammonia oxidation)-hydrolysis denitrification-hydrolysis deep denitrification-aerobic nitrification-post-oxidation (double-oxidation coupled O / H / H / O) coking wastewater treatment process and application. One of the reinforced short-cut nitrification and denitrification fluidized bed combined process is named double-oxidation coupled O / H / H / O process. The first aerobic unit O1 is called carbon removal and ammonia oxidation unit, the second aerobic unit O2 is called complete nitrification unit, and the two H units are called hydrolysis denitrification units, including anaerobic ammonia oxidation, autotrophic denitrification and heterotrophic denitrification function arrangement / editing. Among them, O1 tank has efficient mass transfer and unique independent sludge system, which has the conditions for characteristic microbial domestication and enrichment, and can realize efficient carbon removal and directional total nitrogen normalization under high influent load conditions. For different denitrification modes, the two H units can be named as H1 unit and H2 unit. The former realizes low energy consumption and high load denitrification, and the latter realizes deep denitrification and stabilizes the total nitrogen in the effluent. The front and rear double-oxidation combination control separates the raw water into different qualities, and through the operation of exceeding and recycling, the inherent energy of the raw water is fully utilized, and the addition of external energy and materials is greatly reduced.

[0016] The innovation and significance of the proposed O / H / H / O process are as follows: ① The aerobic unit O1 is placed in the front position for the first time, which realizes the complete carbon removal and ammoniation (or partial nitrification) of industrial wastewater with high toxicity, high organic load and high refractory pollutants, and the directional normalization of total nitrogen, which creates suitable water environmental conditions for denitrification, especially for Anammox reaction which is easily inhibited by toxicity; ② The double O unit realizes the efficient allocation of aeration energy by regulating the nitrogen transformation, such as the DO of O1 and O2 is maintained at 1.0-2.5 mg / L and 3.0-5.0 mg / L, respectively, and the gas-water ratio is 12:1-20:1 and 5:1-10:1, respectively. Compared with the gas-water ratio of 40:1-50:1 in the original A / A / O single-oxygen process, the aeration energy consumption of the O / H / H / O double-oxygen reactor is reduced by about 40%-55%. Moreover, the energy consumption of the O2 reactor is entirely used for nitrification, without a large proportion of reflux, carbon source interference and overload risk, while maintaining high organic load and sludge load, and improving energy utilization efficiency; ③ Unlike A / A / O, the double H unit breaks away from the limitation of large-scale reflux of nitrated liquid for denitrification, and can always maintain anaerobic state and low ORP environment (below -100 mV), avoiding metabolic disorder of microorganisms and collapse of denitrification function, which is not realized by the second A unit in the A / A / O process; ④ The synergy of double physical can maximize the use of endogenous electron donors separated and transformed from wastewater, reduce the increase of process salt caused by dosing, and reduce the investment and operating cost of subsequent desalination; ⑤ The management and regulation of carbon source and heavy metals in double physical can greatly reduce the energy and material consumption of the system; ⑥ The O / H / H / O process with four sludge systems realizes the spatial reorganization and distribution of functional microorganisms, avoids the microbial disorder caused by sludge reflux, and significantly shortens the total HRT when removing TN under the same influent load; ⑦ The O / H / H / O process and the editability at the microbial level provide multiple modes and more suitable process regulation for variable composite industrial wastewater; ⑧ In addition, the O / H / H / O process is suitable in principle for Anammox-based coupled denitrification reaction, which is reflected in the possibility of multiple mode editing for Anammox denitrification pathway by double O / double H, such as O1 can create water quality conditions for direct Anammox reaction, or indirectly Anammox reaction can be realized by adding metal sulfide in H1 unit to drive short-term denitrification of nitrate, or when residual nitrate is refluxed to H2 by O2 unit, TN can be further reduced, providing double insurance for the goal of TN concentration tending to zero.

[0017] In O / H / H / O process, the source of carbon and inorganic electron donor includes sulfide, organic matter and low valence iron salt precipitate contained in pretreatment coagulation sedimentation separator, organic matter in influent, sludge carbon source or digestion liquor after cell rupture. When O1 achieves anaerobic ammonia oxidation water quality stoichiometric ratio or appropriate nitrate nitrogen excess, Anammox reaction is achieved in H1 reactor, autotrophic denitrification reaction (Auden) is achieved in H2 reactor, the most energy-saving and carbon source-free total nitrogen zero-approaching denitrification mode appears; in the whole process, there is no sludge backflow, and no digestion liquor and mixed liquor backflow is needed, the electron donor separated and transformed from wastewater is maximized, the increase of process salt caused by dosing is reduced, and the investment and operation cost of the whole process is reduced.

[0018] The discovery of O / H / H / O process is derived from the inspiration obtained in long-time stable operation of O / H / O process, in the process of modifying A / A / O process, a preposed aerobic fluidized bed is used, the two A units of the original process are modified into H1 and H2 units respectively, the fluidized bed structure of sludge in-situ separation is used, and the process parameters are adjusted. The transition of theoretical understanding of O / H / H / O process to engineering practice becomes a reality.

[0019] To achieve the above purpose, based on the high-efficiency three-phase biological fluidized bed aerobic unit published by our team, which has both attached growth method and suspended growth characteristics, it is a typical composite system. The design structure of the fluidized bed mainly includes draft tube and three-phase separation zone. The fluidized bed draft tube makes the fluid realize internal circulation, which strengthens the mixing and mass transfer performance of the fluidized bed. The three-phase separation zone of the fluidized bed makes the activated sludge separated from the liquid by the drag force and is sucked into the downflow zone of the main unit from the bottom of the inclined wall of the separation zone, avoiding the outflow of the bacteria gel with the water, ensuring the amount of microorganisms in the unit and realizing the reduction of excess sludge. Our practice proves that the fluidization operation mode of the biological fluidized bed creates good mixing and mass transfer conditions between wastewater and microorganisms in the unit. The transfer rates of oxygen and substrate are significantly improved compared with the activated sludge system of fixed bed and boiling bed. We realize the size deformation of the square structure and rectangular structure of the fluidized bed, and realize the design of large-scale. The process has unique advantages in the treatment of high-concentration toxic / difficult-degradable organic wastewater. Through internal structure optimization design, the unit is divided into functional zones. The upflow zone realizes decarburization, i.e. the survival environment of heterotrophic bacteria to remove COD. The downflow zone creates an environment for cultivating nitrosation / nitrification bacteria to ensure the separate growth of carbon oxidation bacteria and nitrosation / nitrification bacteria. Functional design increases the concentration of nitrosation / nitrification bacteria by 4-8 times, making it easier to control the nitrosation / nitrification reaction. At the same time, the biological unit combines the advantages of complete mixing flow and plug flow reactor, greatly enhancing the impact resistance of toxic substances and various loads. Further, through the optimization design of structure and energy, all units do not need dilution water. The nitration reaction realizes feedback control of different section aeration intensity through internal reactor structure design, adopts multi-parameter real-time dynamic control strategy under the control of dissolved oxygen, and builds the environmental conditions for the reproduction of ammonia-oxidizing bacteria (AOB) in the biofilm, i.e. the ammonia and nitration of organic nitrogen and inorganic nitrogen in O1 unit and the controllable nitration / nitration process of ammonia nitrogen; In H1 / H2 unit, anaerobic ammonia oxidation, autotrophic denitrification and heterotrophic denitrification are realized to produce a large amount of nitrogen; In O2 unit, complete nitrification process is realized to ensure the complete conversion of ammonia nitrogen / nitrite nitrogen, while saving energy consumption and alkali consumption. The sludge selector separates the apoptotic sludge in situ, increases the efficiency of the reactor by several times, preferentially removes toxic pollutants, combines the functions of denitrification, innovates the oxygen supply principle, uses electron donors and organic sludge, significantly reduces the volume and area of the unit structure, and the total energy consumption is about 3 / 4 of that of A / A / O process.The realization of high-efficiency fluidized bed, especially rectangular horizontal fluidized bed, makes the large-scale and reasonable structure of the reactor device, the activated sludge concentration of which is 8-10 g / L, the activated sludge concentration of the hydrolysis denitrification unit is 6-8 g / L, the O2 nitrification fluidized bed, the nitrifying bacteria content is 4-6 g / L (the nitrifying bacteria content of general activated sludge system is less than 0.8 g / L), the high-efficiency bacteria have strong toxic tolerance, the system has strong load resistance and toxic shock resistance, and the COD, total nitrogen, ammonia nitrogen and other toxic and harmful pollutants in the effluent can be stably treated to reach the standard under the condition that the influent does not need clean water dilution.

[0020] The present application is aimed at the proposed double physical-chemical coupling O / H / H / O biochemical process, wherein the front / back physical-chemical process guarantees the influent and effluent of the biochemical system, therefore the technical scheme of the present application comprises the front / back physical-chemical process and the biochemical process, which are specifically described as follows:

[0021] (1) Front physical-chemical process: the front physical-chemical process is a pretreatment stage of biological reaction, which comprises a reaction zone, a flocculation zone and a sedimentation zone. The hydraulic retention time (HRT) of the reaction zone and the flocculation zone is 1 h, and the HRT of the sediment is about 8-10 h. Raw water (mainly ammonia distillation wastewater) enters the front physical-chemical reaction zone, and through the addition of ferrous sulfate, the CN-, SCN-, S 2– and other inorganic substances in the raw water are precipitated / complexed. The flocculation zone is provided with a high-molecular flocculant PAM, and after sufficient stirring, the water phase enters the sedimentation zone, and the sediment is separated from the water phase. The water phase enters the water collection and adjustment unit, and the separated sludge phase enters the sludge storage tank. In addition, the sludge obtained by this method contains a large amount of low-toxicity reducing inorganic substances, such as ferrous sulfide (FeS), iron sulfide (Fe2S3), prussian blue (Fe4[Fe(CN)6]3) and other precipitates, which can be used as autotrophic denitrification electron donors. A large amount of research results of the present team show that the front physical-chemical sludge driven autotrophic denitrification is feasible, and has a very complete nitrate / nitrite reduction rate. The front physical-chemical sludge replaces organic matter as an electron donor, not only reduces the utilization of carbon source, but also avoids the problems of organic matter penetration and COD escape.

[0022] (2) Adjustment unit: the adjustment unit plays a role in uniform water quality and quantity. In addition to the front physical-chemical effluent, the wastewater entering the adjustment unit also includes sludge filter liquor, plant rainwater, road washing water and other wastewater. The adjustment unit is fully mixed by aeration and plug flow. The influent of the O1 unit pumped from the adjustment unit is biological supernatant, and the influent of the H1 or H2 unit is super water. The amount of biological supernatant and super water is set according to the needs.

[0023] (3) O1 unit: the HRT of the O1 unit is 50-60 h, the gas-water ratio is 12:1-20:1, the DO value is about 1-2 mg / L, the pH value is controlled at 6.5-7.0, and the organic load is generally 0.8-1.2 kg-COD / m 3 / d, up to 1.6 kg~COD / m 3 / d, COD removal rate can be up to 85%~90%. On this basis, according to the demand of denitrification mode, the DO value is controlled at 2~3 mg / L, and the nitrification rate can be up to 85%~95%. In fact, in order to ensure a high influent load, the influent COD should not be lower than 1500 mg / L, and in order not to waste carbon source, the influent COD should not be higher than 5000 mg / L, otherwise the available carbon source should be extracted through the pretreatment stage first. The influent is supplemented with appropriate phosphorus salt to meet the needs of microbial growth, and liquid alkali is supplemented to maintain the alkalinity required for nitrosation / nitrification according to the change of pH value. The Roots blower provides sufficient dissolved oxygen for the aerobic biological reaction, and also serves the purpose of mixing and stirring. The aerobic microorganisms are enriched in the O1 unit and can run stably in the environment of high influent load and high toxicity. The effluent is separated by a three-phase separator to realize the separation of gas, liquid and solid. The solid phase sludge returns to the O1 unit, and part of the aged sludge is discharged to the sludge concentration unit by the sludge pump.

[0024] (4) H1 unit: the HRT of the H1 unit is 30~40h, and the DO is controlled at 0~0.2 mg / L. The O1 unit effluent flows into the H1 unit. In order to establish composite nutrient denitrification, the form of total nitrogen entering the H1 is adjusted by the O1 according to the needs to realize different modes of denitrification pathway. The specific implementation cases are further described. The bottom of the H1 unit adopts plug flow stirring mixing mode to build a heterotrophic denitrification / autotrophic denitrification survival environment; the top adopts packing to build an autotrophic denitrification / anaerobic ammonia oxidation survival environment. The influent is uniformly fed from the bottom through the water distribution pipe, and then uniformly discharged from the top weir tank.

[0025] (5) H2 unit: the HRT of the H2 unit is 25~30h, and the DO is controlled at 0~0.5 mg / L. The H1 weir tank effluent flows into the H2 unit. Generally, most of the total nitrogen can be removed in the H1, but because of the remaining nitrate nitrogen produced by anaerobic ammonia oxidation and the limitation of low rate of autotrophic denitrification, in order to ensure complete denitrification and reduce the operation cost of denitrification, the H2 unit needs to be added. The combination of H1 / H2 not only provides double insurance for denitrification, but also provides multiple combinations for denitrification, which is described in detail through implementation cases. At the same time, the nitrification liquid of O2 and the sludge in the secondary sedimentation tank are backflowed to the H2 unit according to the actual needs through the principle of gas stripping, to maintain a higher sludge concentration in the H2. Similarly, the H2 unit adopts plug flow stirring mixing to ensure sufficient contact between sludge and water.

[0026] (6) O2 unit: the HRT of the O2 unit is 24-36 h, the DO is controlled to be above 3 mg / L, and the pH value is controlled to be above 7.5 to maintain the alkalinity required for complete nitrification. The COD entering the O2 unit is generally only 200-400 mg / L, mainly being biologically refractory organic matter. The O2 unit also uses a high-efficiency fluidized bed, and in addition to thoroughly carbonizing the residual carbon source of the upstream reaction unit, more importantly, the small amount of ammonia nitrogen and reducing inorganic matter that was not completely nitrified in the O1 tank is completely nitrified / oxidized, and deep denitrification is achieved through reflux of H2. According to the project index requirements, if the total nitrogen of the H2 effluent has reached the standard, then there is no need for reflux of the nitrification liquid of the O2. The O2 effluent is subjected to sludge-water separation in a secondary sedimentation tank, a small amount of solid-phase sludge is refluxed into the H2 or O2 tank, and the water phase is gravity-fed to the post-physical and chemical treatment unit. In fact, in addition to suspended solids and COD, the secondary sedimentation tank effluent can already meet the design discharge standard.

[0027] In summary, in the O / H / H / O biochemical process, first, the physical and chemical process needs to provide an electron donor, the O1 unit provides a denitrification water quality environment condition through carbon removal and ammonification / nitritation, the H1 reactor removes most (more than 70% of the total nitrogen) through the combination of anaerobic ammonia oxidation and partial heterotrophic denitrification, the H2 reactor completely converts the residual nitrate nitrogen (nitrate and nitrite) into nitrogen gas (when the electron donor is excessive, the effect of total nitrogen concentration tending to zero can be obtained), and then, the residual low-valence nitrogen, reducing inorganic matter, and residual BOD components in the wastewater are completely oxidized and removed by the O2 reactor. This embodies the technical feature of the O / H / H / O process of carbon removal and denitrification coupling.

[0028] (7) Post-physical and chemical treatment: the biological system effluent enters a dosing unit, where polyferric sulfate, activated carbon, liquid caustic soda, and PAM are sequentially added and mixed and reacted to remove residual biologically refractory and organic matter produced by microorganisms themselves. The sludge (containing unsaturated activated carbon) of the post-physical and chemical treatment unit is pumped to the pre-physical and chemical treatment unit as secondary-use chemicals after being separated. The effluent is filtered by a microfiltration machine, is clear and transparent, meets the design discharge standard, and meets the zero discharge into the membrane requirement.

[0029] (8) In particular, for the pre-physical and chemical treatment of the process, the separated reducing sludge (including reducing organic matter and inorganic matter) can be used as an internal carbon source for denitrification, reducing or even eliminating the need for the addition of an external carbon source; for the post-physical and chemical treatment of the process, the obtained inorganic sludge containing unsaturated adsorbent can be reused in the pre-physical and chemical treatment to exert the remaining adsorption capacity, reduce the influent load of the biological unit, and reduce the aeration amount and the addition of materials.

[0030] (9) The dual-physical and chemical coupling O / H / H / O process has the characteristics of wide applicability, simple construction, and easy operation. It is not only suitable for new projects, but can also be easily applied to modification projects of commonly used processes (such as AAO, AOO, etc.).

[0031] Compared with the prior art, the present application has the advantages of:

[0032] The present application truly realizes the connection of the treatment of high-COD, high-toxicity and high-total-nitrogen wastewater to the zero discharge into membrane water quality. Under the same influent load and engineering scale conditions, the concentrations of COD, ammonia nitrogen, total nitrogen and polycyclic aromatic hydrocarbons in the treated water are lower than those of the A / A / O process, and the water quality is better. Except that the engineering investment is about 15% higher, the unit treatment energy consumption and operation cost are significantly reduced. The energy consumption is about 70% to 80% of that of the A / A / O process, and the operation cost is reduced by 2 to 4 yuan / m 3 The stability of operation is obviously superior to that of the A / A / O process. The key is to overcome the technical bottleneck of the total nitrogen tending to zero. BRIEF DESCRIPTION OF DRAWINGS

[0033] The present application will be further described below in combination with the drawings and implementation cases.

[0034] Figure 1 It is a double physical-chemical coupling O / H / H / O process flow diagram for treating typical industrial wastewater.

[0035] Figure 2 It is a double physical-chemical coupling O / H / H / O biological process elevation diagram based on a fluidized bed.

[0036] Figure 3 It is a modification scheme based on the existing AAO project (implementation case 1)

[0037] Figure 4 It is a modification site based on the existing AAO project (implementation case 1)

[0038] Figure 5 It is a modification site of the double physical-chemical coupling O / H / H / O process of each unit (implementation case 1).

[0039] Figure 6 It is a double physical-chemical coupling O / H / H / O process flow based on the modified treatment of typical industrial wastewater (implementation case 2).

[0040] Figure 7 It is a double physical-chemical coupling O / H / H / O process flow based on the modified treatment of typical industrial wastewater (implementation case 3).

[0041] Figure 8 It is a double physical-chemical coupling O / H / H / O process flow based on the modified treatment of typical industrial wastewater (implementation case 4).

[0042] Figure 9 It is a double physical-chemical coupling O / H / H / O process flow based on the modified treatment of typical industrial wastewater (implementation case 5).

[0043] Figure 10 The water samples are raw water (left), effluent of biological system (middle) and effluent of advanced treatment (right). DETAILED DESCRIPTION

[0044] The application will be further described in detail in combination with specific implementation cases.

[0045] The main process flow is shown in Figure 1 and Figure 2 The application discloses a double physical-chemical coupling O / H / H / O wastewater treatment process based on a fluidized bed, wherein Figure 1 is a schematic diagram of the double physical-chemical coupling O / H / H / O process flow, Figure 2 is a high-level schematic diagram of the double physical-chemical coupling O / H / H / O.

[0046] The pre-physical-chemical 1 is the pretreatment of the biological system. After the wastewater is subjected to the pre-physical-chemical, inorganic toxic ions such as cyanide, thiocyanide and sulfide are converted into low-toxicity metal cyanide, metal thiocyanide and metal sulfide, thereby greatly reducing the toxicity of the wastewater. Further, the slanted tube sedimentation structure 1-2 is constructed, and solid-liquid separation is realized in the separation zone 1-1. According to process regulation, the separated inorganic reducing solid phase (sludge) can be used as an autotrophic denitrification electron donor, and is introduced into the H1 unit 4 through a sludge pump and a valve 38.

[0047] The coking wastewater mixture in the water collecting and regulating unit 2 is pumped by the O1 water supply pump 8, flows into the O1 unit descending zone 3-2 through the O1 water inlet valve 9 and the water inlet 15, and moves downward to the bottom of the O1 unit in the O1 unit descending zone 3-2. Under the traction of fluid mechanics, the coking wastewater enters the O1 unit ascending zone 3-1. The remaining part of the coking wastewater mixture can enter the H1 unit mixing zone 4-1 through the hydrolysis unit bypass pump 10 and the H1 bypass water inlet valve 11 and the water inlet 16, or enter the H2 unit through the H2 bypass water inlet valve 37. Generally, the O1 unit biological water inlet / H2 bypass water is 10:1-3:1, and is determined synchronously with the operation process scheme.

[0048] O1 and O2 units are provided with baffle or guide baffle auxiliary units to assist the formation of fluidized circulation in the units. The volume ratio of the ascending zone to the descending zone is determined according to actual requirements, and according to engineering experience, it can be controlled at 1:1-5:1. The lower part of the ascending zone 3-1 of the O1 unit is provided with an aeration device 12. The upper part of the descending zone 3-2 of the O1 unit is provided with a water outlet weir tank 13, and the lower part of the water outlet weir tank 13 is connected with the top of a three-phase separator 14. In the three-phase separator 14, solid-phase substances can return to the fluidized area of the descending zone 3-2 of the O1 unit through the guide pipe at the lower part of the three-phase separator 14 to return to the fluidized circulation, and the gas phase-liquid phase-solid phase enters the water outlet weir tank 13 from the water outlet pipe at the upper part of the three-phase separator 14, and the gas phase is separated from the liquid phase here.

[0049] The bottom of the mixing zone 4-1 of the H1 unit is provided with an underwater pusher group 17, and the number of underwater pushers is determined according to actual requirements. The underwater pusher group 17 is used for stirring mixing to ensure sufficient contact between the sludge and the wastewater in the H1 unit. The packing zone 4-2 of the H1 unit is provided with suspended packing 19 for microorganisms to adhere to. The H1 unit is provided with a water outlet weir tank 18 at the water outlet. The aged sludge is discharged through a sludge discharge valve 30.

[0050] The bottom of the H2 tank is the reaction zone 5-1, which is provided with an underwater pusher group 20, and the number of underwater pushers is determined according to actual requirements. The H2 tank receives the water inlet of the upper H1 tank, and carbon source or electron donor can be added for biological heterotrophic or autotrophic denitrification reaction. The carbon source in the carbon source storage tank 39 flows into the H1 / H2 tank under the control of the carbon source feeding valve 40. The H2 tank has an independent separation zone 5-2 to realize sludge-water separation. The separation zone 5-2 is provided with an independent water outlet weir tank 21.

[0051] The mixing zone 4-1 of the H1 unit is in a heterotrophic or autotrophic denitrification mode for denitrification, and the packing zone 3-2 is in an anaerobic ammonia oxidation mode for denitrification. The coking wastewater flows into the H1 unit, and due to the control of the O1 unit on DO, most of the nitrogen in the inflowing coking wastewater exists in the form of nitrate nitrogen and nitrite nitrogen. At the same time, the H1 unit also receives a small part of the coking wastewater from the water collection and adjustment unit, and the coking wastewater contains ammonia nitrogen and reducing electron donor, which is pumped by the hydrolysis unit overflow pump 10, flows through the H1 overflow inlet valve 11, and enters the mixing zone 4-1 of the H1 unit through the water inlet 16. The position of the water inlet 16 can be arranged in or below the packing zone 4-2 of the H1 unit. The suspended packing 19 in the packing zone 4-2 of the H1 unit is attached with anaerobic ammonia oxidation bacteria, and ammonia nitrogen can react with nitrite nitrogen to produce anaerobic ammonia oxidation reaction under the action of the anaerobic ammonia oxidation bacteria, which is one of the denitrification modes. In the mixing zone 4-1 of the H1 unit, autotrophic denitrifying bacteria are cultured, and nitrate or nitrite can react with reducing electron donors such as sulfide to produce autotrophic denitrification reaction, so as to realize nitrogen removal.

[0052] The lower part of the O2 unit rising zone 6-1 is provided with an aeration device 22, and the O2 unit is circulated in a fluidized state under the air flow of the aeration device 22. The upper part of the O2 unit falling zone 6-2 and the position close to the O2 unit effluent weir tank 25 are provided with a nitrification liquid return port, and the nitrification liquid returns to the H2 unit through the secondary aerobic digestion liquid return valve 23 under the pumping of the O2 unit nitrification liquid return pump 24, so as to realize the denitrification reaction of the residual nitrate nitrogen in the return liquid and guarantee the complete removal of total nitrogen in the system. In the three-phase separator 29, the solid phase material can return to the fluidized area of the O2 unit falling zone 6-2 to return to the fluidized circulation through the flow guide pipe at the lower part of the three-phase separator 29, and the gas phase-liquid phase-solid phase enters the effluent weir tank 25 through the effluent pipe at the upper part of the three-phase separator 29, and the gas phase is separated from the liquid phase.

[0053] The O1 unit, the H1 unit, the H2 unit and the O2 unit are all provided with independent sludge discharge systems, and the sludge discharge is controlled by independent sludge valves 31, 30, 28 and 26 respectively. All the biological sludge is independent sludge, and is not mixed with each other during the process operation, so as to realize the independent sludge properties and functions. When the sludge is discharged, the sludge enters the sludge filter press 35 through the respective sludge discharge pipelines, the sludge treated by pressure filtration is transported out of the water treatment plant by a sludge transport vehicle for sludge incineration treatment, and the pressure filtration water left after the pressure filtration treatment returns to the water collection and adjustment unit.

[0054] The aeration device 12 in the O1 unit and the aeration device 22 in the O2 unit can be uniformly supplied with air by the Roots blower 33. The aeration device 12 in the O1 unit realizes aeration amount control by the air amount adjusting valve 32. The aeration device 22 in the O2 unit realizes aeration amount control by the air amount adjusting valve 27. The air-water ratio of the O1 unit is controlled to be 12:1-20:1, and the air-water ratio of the O2 unit is controlled to be 5:1-10:1, which needs to be determined according to the organic load and the reactor efficiency.

[0055] The biological effluent still contains a large amount of suspended solids and difficult-to-biodegrade organic substances, which need to be further treated before being discharged to the downstream process. The post-physical treatment 7 realizes the purification of the biological effluent by adding different reagents, mainly including adding activated carbon 7-1, polyferric sulfate 7-2, pH adjusting agent and flocculant PAM 7-3, and finally realizing solid-liquid separation through the inclined pipe precipitation member 7-5 of the precipitation zone 7-4. The obtained post-physical treatment sludge contains unsaturated activated carbon, which can be returned to the pre-physical treatment through the return pump and valve 41, so as to realize complete resource utilization, reduce the subsequent biological treatment process, and reduce the material consumption and energy consumption, which will be illustrated by specific implementation cases.

[0056] The application will be described and analyzed in further detail in combination with a specific industrial wastewater (taking coking wastewater as an example) treatment plant case, but not as a limitation of the application. The implementation case of the application is derived from a coking wastewater treatment plant in Shaoguan, Guangdong, the original water pH is about 9.0-9.8, COD is about 3400-4200 mg / L, about 50-70 mg / L, TN is about 280-360 mg / L, the design standard is COD≤80 mg / L, TN≤20 mg / L, and the rest of the indexes are shown in the specific implementation case.

[0057] Example 1

[0058] The implementation case is directed to the built coking wastewater pre-physicochemical + A / A / O + post-physicochemical treatment process, and proposes a high organic load and high denitrification efficiency double-physicochemical coupled O / H / H / O biochemical reconstruction process, wherein A1 is an anaerobic unit, A2 is an anoxic unit, O is an aerobic unit, and the O unit bears the heavy burden of mineralization / nitrification. The specific implementation steps of A / A / O are as follows.

[0059] (1) The original water quantity is about 55 m 3 / h, the ferrous sulfate dosage of the pre-physicochemical is 50 kg / h, the PAM dosage is 0.04 kg / h, the pre-physicochemical process converts inorganic toxic ions such as cyanide, thiocyanide and sulfide into low-toxicity metal cyanide, metal thiocyanide and metal sulfide, part of which is removed from the water phase by precipitation, and part of which enters the biological system for complete degradation. After the pre-physicochemical unit, the cyanide is reduced from 10-20 mg / L to 1.0-1.5 mg / L, the sulfide is reduced from 30-40 mg / L to 5-8 mg / L, and the thiocyanide is converted into ferric thiocyanate, which greatly reduces the toxicity of the influent.

[0060] (2) The biological upper water quantity is about 60 m 3 / h, which includes sludge filter press filtrate and ground washing wastewater, and sequentially enters the anaerobic unit Al, the anoxic unit A2, and the aerobic unit O (before the modification), with residence times of 30 h, 25 h, and 50 h, respectively. Among them, the coking wastewater is characterized by a lack of phosphorus, and the Al unit mainly plays a role in hydrolyzing refractory organic matter, while having little contribution to the direct removal of COD. The dissolved oxygen in the Al unit is close to zero, and the pH often reaches 8.0-8.5. The A2 unit utilizes the organic matter brought by part of the raw water to achieve heterotrophic denitrification, but due to the inhibition of high-concentration toxic substances, the denitrification process in the A2 unit is significantly inhibited, making it difficult to achieve good denitrification effect. Due to the action of a large proportion of nitrification liquid in the aerobic unit O, the dissolved oxygen in the A2 unit reaches 0.2-0.5 mg / L, with local areas reaching more than 0.5 mg / L, and the pH reaches 7.4-7.9, failing to achieve the optimal pH environment for heterotrophic denitrification. The internal reflux ratio of the nitrification liquid in the O unit is about 4-6, and the sludge reflux ratio is about 0.5, both of which are refluxed to the A2 anoxic unit, at which time the theoretical total nitrogen removal rate is 82%-87%. During the operation of the O unit, the gas-water ratio is higher than 50:1, the dissolved oxygen is controlled at 4-5 mg / L, liquid alkali is added to maintain the pH at weak alkaline, and appropriate phosphorus salt is supplemented. The post-physical unit has a polyiron dosage of 72 L / h (slurry, density 1.58 g / cm 3 ), an activated carbon dosage of 24 kg / h, and a PAM dosage of 0.2 kg / h. The biological effluent is further controlled in turbidity, color, suspended solids, and COD after the post-physical treatment.

[0061] (3) In fact, due to the dilution effect and dissolved oxygen brought by a large proportion of reflux, part of the available organic matter is consumed, the total nitrogen load is reduced, the total nitrogen residence time is reduced, and the functional expression of characteristic microorganisms is disturbed. A large amount of engineering operation data shows that the total nitrogen removal efficiency at this time is far from the theoretical design value. Before the modification, the COD, ammonia nitrogen total nitrogen (TN), and other main indicators of each unit are shown in Table 1. Among them, we found that the COD removal rate of the Al unit was only 12%-17%. The A2 unit and the O unit are almost mixed into the same reactor due to a large proportion of reflux, and the change trend of the effluent water quality remains consistent, with a COD removal rate of about 80%-83%, of which 20% comes from the contribution of the dilution of reclaimed water. The total nitrogen removal rate relying on nitrification liquid reflux denitrification is about 74%-80%, which is the upper limit that the biochemical system can achieve before the modification.

[0062] Table 1 Main water quality indicators of each unit

[0063]

[0064] Note: L represents lower than the detection limit; N.D. represents not detected.

[0065] (4) Total effluent, i.e. post-chemicalization effluent, cannot fully meet the direct discharge limit value of "Coke Chemical Industry Pollutant Discharge Standard" (GB16171-2012) and the enterprise internal control standard. As shown in Table 2, the main pollutants exceeding the standard are COD, TN and cyanide. Compared with the raw water quality, the COD removal rate is 94.0% to 95.0%, the TN removal rate is 80.0% to 85.7%, and the cyanide removal rate is 97.0% to 97.2%. The main reason for the failure to meet the standard of COD, TN and cyanide is that the microbial function of the pre-anaerobic tank / hypoxic tank is inhibited by the toxicity of the influent, and the method of large-scale reflux denitrification is restricted by the principle, and the denitrification process cannot be significantly broken through.

[0066] Table 2 Water quality indicators of total effluent

[0067]

[0068] Note: L represents lower than the detection limit; N.D. represents not detected.

[0069] (5) The estimated operating cost before the transformation is shown in Table 3. According to experience, labor cost and sludge treatment and disposal cost account for 10% and 5% of the total operating cost, but labor cost and sludge treatment cost are not considered in this estimation and analysis. The water cost of reagent is converted into reagent cost, and the aeration energy cost is converted into compressed air cost of 0.1 yuan / m 3 , industrial electricity price 0.6 yuan / (kW·h), ferrous sulfate hydrate 300 yuan / ton, anionic PAM 8000 yuan / ton, 30% caustic soda 1400 yuan / ton, industrial glucose 1500 yuan / ton, sodium dihydrogen phosphate 4000 yuan / ton, slurry state polyferric chloride 750 yuan / ton, and powdered activated carbon (iodine adsorption value 600 mg / g) 6000 yuan / ton.

[0070] Table 3 Partial operating cost estimation table Unit: yuan / m 3 wastewater

[0071]

[0072]

[0073] The total operating cost of the above-mentioned double chemicalization + A / A / O process is 13.842 yuan / m 3 wastewater. The operating units with the highest cost are the post-chemicalization unit and the aerobic O unit, which account for 43.3% of the total operating cost. The reagent cost accounts for 54.5% of the total cost, and the rest is the power consumption cost, of which the aeration power consumption accounts for 87.9% of the total power consumption. The operating cost of the biological system is about 7.187 yuan / m 3 wastewater, accounting for 51.9% of the total operating cost.

[0074] ​(6) According to the problems existing in the foregoing built process, it is necessary to make necessary upgrading and reconstruction. The double-physicochemical coupling O / H / H / O process is verified by actual engineering, which can be applied to the treatment of typical industrial wastewater with high toxicity, high carbon-nitrogen ratio and high total nitrogen content. The double-physicochemical coupling O / H / H / O engineering reconstruction scheme and process are shown in Figure 3 、 4 It is noted that before the reconstruction, the anoxic denitrification tank A2, the aerobic tank O and the biological effluent all appear large-area black mud floating phenomenon, which is related to the apoptosis and corruption of microorganisms inhibited by toxicity. The reconstruction scheme of the present application is: the existing front and rear physicochemical units are retained, the front aerobic fluidized bed O1 unit is newly built, and the original A / A / O unit is successively reconstructed into H1 / H2 / O2 unit. In addition to the necessary pipeline system, the adjustment tank override pipeline, the front physicochemical carbon source utilization pipeline and the rear physicochemical sludge recycling pipeline are added. The external factors such as raw water quality conditions, operating conditions and management team before and after the reconstruction are almost unchanged, which ensures the scientific nature of the process comparison.

[0075] (7) After the upgrading and reconstruction, the HRT of each biological unit of O / H / H / O is 55h, 30h, 25h and 50h respectively. Although the HRT is increased, the front placement of the aerobic unit O1 can effectively avoid the toxic inhibition effect, and can greatly improve the organic load of the aerobic unit (the highest can reach 1.6-2.0 kg-COD / m 3 / d). Without the need for supplemental dilution water, the effective wastewater treatment capacity can be increased, and the mutagenicity of the organic load of the wastewater has greater buffering capacity. More importantly, the total gas-water ratio of the aerobic unit is reduced from 50:1 to 25:1 without a large proportion of reflux, and the carbon source management unit further reduces the additional organic carbon, so that the average wastewater treatment cost per cubic meter can be reduced from 13.8 yuan to less than 9 yuan, and the operation conditions of each case 2-5 are further discussed.

[0076] Example 2

[0077] The present embodiment is directed to the biochemical process of coking wastewater treatment, and proposes a double-physicochemical coupling O / H / H / O biochemical process with high organic load and high denitrification efficiency, wherein the O1 unit realizes high-efficiency carbon removal and high-efficiency nitrification process, the H1 unit realizes high-efficiency denitrification / anaerobic ammonia oxidation combined denitrification process, the H2 tank realizes complete removal of total nitrogen by heterotrophic denitrification process, and the H2 / O2 unit is also the guarantee of stable effluent quality. The proposed double-physicochemical coupling O / H / H / O biochemical process is based on the reconstruction of the existing A / A / O process, and the engineering operation site is shown in Figure 5 . The operation process specifically includes the following steps, and the technical route of the embodiment case 2 is shown in Figure 6 .

[0078] (1) The raw water volume is about 55m 3 / h, PAM dosage 0.04 kg / h, inorganic toxic ions such as cyanide, thiocyanide and sulfide are converted into low-toxicity metal cyanide, metal thiocyanide and metal sulfide in the pre-chemical unit, part of which is removed from the water phase by precipitation and part of which enters the biological system for complete degradation. After the pre-chemical unit, cyanide is reduced from 10-20 mg / L to 1.0-1.5 mg / L, sulfide is reduced from 30-40 mg / L to 5-8 mg / L, and thiocyanide is converted into ferric thiocyanate, greatly reducing the toxicity of the influent.

[0079] (2) The biological supernatant water has a volume of about 60 m 3 / h, which includes sludge filter press filtrate and ground washing wastewater, etc., enters the O1 unit to achieve a circulating fluidized state by air agitation and a special structure, the gas-water ratio is 20:1, the influent load is 1.1-1.3 kg-COD / m 3 / d, DO is controlled at 1.5-2.0 mg / L, pH is controlled at 6.5-7.0, COD is reduced from 2500-3000 mg / L to 250-300 mg / L, ammonia nitrogen is reduced from 60-90 mg / L to 1-1.2 mg / L, total nitrogen is reduced from 200-230 mg / L to 160-180 mg / L, of which nitrate nitrogen is 150-165 mg / L, and the nitrification rate is higher than 91%.

[0080] (3) Glucose is added as a denitrification carbon source in the H1 unit, the dosage is 37.5 kg / h, the effective ingredient is 90%, and the glucose B / C value is about 0.8, so the influent BOD / N = 2.8-3.0. The hydraulic retention time of the H1 unit is 30-40 h, DO is controlled at 0-0.2 mg / L, pH is maintained at 6.5-7.0, and total nitrogen is reduced from 160-180 mg / L to 16-20 mg / L.

[0081] (4) It is observed that the COD of the H1 effluent is about 20 mg / L higher than that of the influent, which is because the added carbon source is not completely utilized, causing COD to escape, so the role of the O2 unit can ensure that the escaped COD is further completely degraded, and the ammonia nitrogen that is not completely nitrified in the O1 unit is also further nitrified in the O2 unit. When the H1 unit has completed most of the denitrification goal, the H2 unit only plays a hydrolysis role.

[0082] (5) The total residence time of the post-chemical unit is about 10 h, the poly-iron dosage is 72 L / h (slurry, density 1.58 g / cm 3 ), the activated carbon dosage is 24 kg / h, and the PAM dosage is 0.2 kg / h. After the post-chemical treatment of the biological effluent, the turbidity is reduced from 750-800 NTU to below 5 NTU, and the COD is reduced from 200-240 mg / L to 80-100 mg / L.

[0083] (5) Sodium phosphate monobasic dosage is 6.25 kg / h, and is added to O1 and O2 units respectively according to the ratio of 2:1. Liquid alkali (mass concentration 30%) is intermittently added, and the dosage is about 145 kg / h, which is added to O1 unit and post-oxidation unit respectively according to the ratio of 7:3.

[0084] COD, ammonia nitrogen of each unit The total nitrogen (TN) index is shown in Table 1.

[0085] Table 4 Main water quality indexes of each unit

[0086]

[0087] Note: L represents lower than the detection limit; N.D. represents not detected.

[0088] The total effluent, i.e. post-oxidation effluent, meets the direct discharge limit value of “Coke Chemical Industry Pollutant Discharge Standard” (GB 16171-2012) and the enterprise internal control standard, as shown in Table 2. Compared with the original water quality, the COD removal rate is higher than 96.6%, and the TN removal rate is higher than 94.4%, the removal rate is higher than 98%.

[0089] The operation cost estimation of the double-oxidation coupled O / H / H / O process is shown in Table 3. According to experience, labor cost and sludge treatment and disposal cost account for 10% and 5% of the total operation cost, but labor cost and sludge treatment cost are not considered in this estimation analysis. The water cost of the configured reagents is converted into the reagent cost, and the aeration energy cost is converted into the compressed air cost of 0.10 yuan / m 3 , the industrial electricity unit price is 0.6 yuan / (kW·h), the hydrated ferrous sulfate is 300 yuan / ton, the anionic PAM is 8000 yuan / ton, the 30% liquid alkali is 1400 yuan / ton, the industrial glucose is 1500 yuan / ton, the sodium phosphate monobasic is 4000 yuan / ton, the slurry state polyferric sulfate is 750 yuan / ton, and the powder activated carbon (iodine adsorption value 600 mg / g) is 6000 yuan / ton.

[0090] Table 5 Total effluent water quality index

[0091]

[0092] Note: L represents lower than the detection limit; N.D. represents not detected.

[0093] Table 6 Part of operation cost estimation table Unit: yuan / m 3 waste water

[0094]

[0095] The total operation cost of the above-mentioned process based on the double-oxidation coupled O / H / H / O is 10.815 yuan / m3 Wastewater, 3.026 yuan / m less than before the transformation 3 Wastewater. The highest cost operating unit is the post-physical unit and the O1 unit, accounting for 37.4% and 35.6% of the total operating cost, respectively. The cost of chemicals accounts for 65.8% of the total cost, and the rest is the cost of electricity consumption. The aeration electricity consumption accounts for 80.9% of the total electricity consumption. The operating cost of the biological system is about 6.118 yuan / m 3 Wastewater, accounting for 56.6% of the total operating cost.

[0096] Example 3

[0097] The embodiment is directed to the biochemical process of coking wastewater treatment. A double-physical coupling O / H / H / O biochemical process with high organic load and high denitrification efficiency is proposed. The O1 unit realizes efficient carbon removal and short nitrification process. The H1 unit realizes high-efficiency autotrophic denitrification process. The H2 / O2 unit realizes heterotrophic denitrification process. The O2 unit is also the guarantee of stable effluent water quality. In addition, the reducing inorganic sludge separated by the pre-physical unit is added to the H1 unit as an autotrophic denitrification electron donor, reducing or even eliminating the need for organic carbon source. The technical route of Example 3 is shown in the following. Figure 7

[0098] (1) The raw water flow is about 55 m 3 / h, the ferrous sulfate dosage is 50 kg / h, and the PAM dosage is 0.04 kg / h. The pre-physical process converts inorganic toxic ions such as cyanide, thiocyanide, and sulfide into low-toxicity metal cyanide, metal thiocyanide, and metal sulfide. Part of them is removed from the water phase by precipitation, and part of them enters the biological system for complete degradation. After the pre-physical unit, the cyanide is reduced from 10-20 mg / L to 1.0-1.5 mg / L, and the sulfide is reduced from 30-40 mg / L to 5-8 mg / L. The thiocyanide is converted into ferric thiocyanate, greatly reducing the toxicity of the influent. The average sludge discharge of the pre-physical unit is about 0.75 m 3 / h, and the inorganic sludge discharged contains a large amount of low-toxicity reducing inorganic electron donors. These electron donors are continuously pumped into the H1 unit to replace organic carbon sources such as glucose as electron donors for H1 autotrophic denitrification.

[0099] (2) The biological upper water flow is about 50 m 3 / h, which includes sludge filter press filtrate and wastewater from ground washing, etc. It enters the O1 unit to realize the state of circulating fluidization through air stirring and special structure. The gas-water ratio is 15:1, and the influent load reaches 1.1-1.3 kg-COD / m 3 ​DO control at 1.5-2.0 mg / L, pH control at 6.5-7.0, COD from 2200-2600 mg / L to 500-800 mg / L, ammonia nitrogen from 60-90 mg / L to 10-15 mg / L, total nitrogen from 250-280 mg / L to 200-230 mg / L, of which nitrite nitrogen 160-180 mg / L, nitrite rate about 80%, nitrate nitrogen 20-30 mg / L, nitration rate about 10%-13%.

[0100] (3) H1 unit adding pre-physicochemical sludge as denitrification electron donor, dosage 0.75 m 3 / h, wherein the effective electron donor components such as sulfide, cyanide, etc. account for about 60%. The hydraulic retention time of H1 unit is 30-40 h, DO control at 0-0.2 mg / L, pH maintained at 6.5-7.0, total nitrogen from 200-230 mg / L to 40-55 mg / L.

[0101] (4) It is observed that the H1 effluent still has 25-27 mg / L ammonia nitrogen and 5-10 mg / L nitrate nitrogen, which is because the cyanide autotrophic denitrification releases part of the ammonia nitrogen, and therefore the role of O2 unit can ensure that the escaped ammonia nitrogen is further completely nitrified, and then returned to H2 unit by gas return pump, with a return ratio of about 200%. In order to supplement the carbon source for denitrification in H2, the water exceeding 10 m 3 / h in the adjustment unit is adjusted to H2, and heterotrophic denitrification is carried out by using the carbon source therein, at which time the BOD / N ratio of H2 influent is about 1.68, and glucose is further supplemented at about 18 kg / h to maintain the BOD / N of influent = 2.95. After H2 / O2 unit, the ammonia nitrogen of biological effluent is further reduced to 1.0-1.5 mg / L, and the total nitrogen is reduced to 16-20 mg / L, which can meet the discharge requirements.

[0102] (5) The total retention time of post-physicochemical unit is about 10 h, the polyferric dosage is 72 L / h (slurry, density 1.58 g / cm 3 ), the activated carbon dosage is 24 kg / h, and the PAM dosage is 0.2 kg / h. After post-physicochemical treatment, the turbidity of biological effluent is reduced from 750-800 NTU to below 5 NTU, and the COD is reduced from 200-240 mg / L to 80-100 mg / L.

[0103] (6) The dosage of sodium dihydrogen phosphate is 6.25 kg / h, which is added to O1 and O2 units respectively according to a ratio of 2:1. Liquid alkali (mass concentration 30%) is intermittently added, with a dosage of about 145 kg / h, which is added to O1 unit and post-physicochemical unit respectively according to a ratio of 7:3.

[0104] The COD, ammonia nitrogen and total nitrogen (TN) indexes of each unit are shown in Table 4.

[0105] Table 7 Main water quality indicators of each unit

[0106]

[0107] Note: L represents below the detection limit; N.D. represents not detected.

[0108] The total effluent, i.e. post-chemicalization effluent, meets the direct discharge limit value of “Coke Chemical Industry Pollutant Discharge Standard” (GB 16171-2012) and the enterprise internal control standard, as shown in Table 5. Compared with the raw water quality, the COD removal rate is higher than 96.0%, the TN removal rate is higher than 94.0%, and the NH3-N removal rate is higher than 98%. The removal rate is higher than 98%.

[0109] Table 8 Water quality indicators of total effluent

[0110]

[0111]

[0112] Note: L represents below the detection limit; N.D. represents not detected.

[0113] The estimated operating cost of the double-chemicalization coupled O / H / H / O process is shown in Table 3. According to experience, labor cost and sludge treatment and disposal cost account for 10% and 5% of the total operating cost, but labor cost and sludge treatment cost are not considered in this estimation and analysis. The water cost of the configured reagents is converted into the cost of reagents, and the aeration energy cost is converted into the cost of compressed air, which is 0.1 yuan / m 3 , the unit price of industrial electricity is 0.6 yuan / (kW·h), the price of ferrous sulfate heptahydrate is 300 yuan / ton, the price of anionic PAM is 8000 yuan / ton, the price of 30% caustic soda is 1400 yuan / ton, the price of industrial glucose is 1500 yuan / ton, the price of sodium dihydrogen phosphate is 4000 yuan / ton, the price of slurry state polyferric chloride is 750 yuan / ton, and the price of powdered activated carbon (iodine adsorption value 600 mg / g) is 6000 yuan / ton.

[0114] Table 9 Partial operating cost estimation table Unit: yuan / m 3 Wastewater

[0115]

[0116] The above process based on double-chemicalization coupled O / H / H / O, in which the most costly operating units are the post-chemicalization unit and the O1 unit, accounting for 39.5% and 30.3% of the total operating cost, respectively, the cost of reagents accounts for 64.6% of the total cost, and the rest is the cost of electricity consumption, in which the aeration electricity consumption accounts for 80.5% of the total electricity consumption. Compared with the implementation case 2, due to the adjustment of the aeration amount of the O1 / O2 unit, the cost of gas consumption is reduced by 0.083 yuan / m 3The cost of the medicine is reduced by 0.488 yuan / m 3 , and the total cost is reduced by 0.571 yuan / m 3 . The operation cost of the biological system is about 5.547 yuan / m 3 , which is lower than that of other processes of the same type.

[0117] Example 4

[0118] The embodiment is directed to the biochemical process of coking wastewater treatment, and proposes a double-physicochemical coupling O / H / H / O biochemical process with high organic load and high denitrification efficiency. The O1 unit realizes efficient carbon removal and ammoniation / partial short-cut nitrification process, the H1 unit realizes anaerobic ammonium oxidation denitrification process, the H2 / O2 unit realizes heterotrophic denitrification deep denitrification process, and the O2 unit is also the guarantee of stable effluent water quality. The technical route of Example 4 is shown in Figure 8 .

[0119] (1) The raw water flow is about 55m 3 / h, the ferrous sulfate dosage before physicochemical treatment is 50 kg / h, and the PAM dosage is 0.04 kg / h. In the pre-physicochemical process, inorganic toxic ions such as cyanide, thiocyanide and sulfide are converted into low-toxicity metal cyanide, metal thiocyanide and metal sulfide. Part of them is removed from the water phase by precipitation, and part of them enters the biological system for complete degradation. After the pre-physicochemical unit, the cyanide is reduced from 10-20 mg / L to 1.0-1.5 mg / L, the sulfide is reduced from 30-40 mg / L to 5-8 mg / L, and the thiocyanide is converted into ferric thiocyanate, which greatly reduces the toxicity of the influent.

[0120] (2) The biological upper water flow is about 55m 3 / h, which includes sludge filter press filtrate and ground washing wastewater, etc. It enters the O1 unit to realize the state of circulating fluidization by air stirring and special structure. The gas-water ratio is 12:1, the influent load is 1.1-1.3 kg-COD / m 3 / d, the DO is controlled at 1.0-1.5 mg / L, the pH is controlled at 6.5-7.0, the COD is reduced from 2200-2600 mg / L to 600-800 mg / L, the ammonia nitrogen is increased from 50-70 mg / L to 65-75 mg / L, and the total nitrogen is reduced from 200-230 mg / L to 160-180 mg / L, of which the nitrite nitrogen is 85-100 mg / L, the nitrosation rate is about 55%, and there is no nitrate nitrogen.

[0121] (3) The influent of H1 unit contains a large amount of nitrite nitrogen and ammonia nitrogen, and the ratio thereof is controlled at about 1.30-1.33, at which the anaerobic ammonia oxidation process is realized under the condition of sufficient alkalinity by the anaerobic ammonia oxidation bacteria added in advance and attached to the filler of H1 unit. The hydraulic retention time of H1 unit is 30-40 h, DO is controlled at 0-0.2 mg / L, pH is maintained at 7.0-7.5, and total nitrogen is reduced from 160-180 mg / L to 25-30 mg / L.

[0122] (4) It is observed that the effluent of H1 still contains 25-30 mg / L of total nitrogen, which is because about 0.26 mol of nitrate nitrogen is produced for each reduction of 1 mol of N2 in the anaerobic ammonia oxidation process. Therefore, the function of H2 unit can ensure that the escaped nitrate nitrogen is further completely denitrified, and the complete nitrification function of O2 unit can ensure that the O1 unit produces a ratio that cannot completely perform anaerobic ammonia oxidation. In order to meet the total nitrogen target, a reflux ratio of about 100% is set. In order to supplement the carbon source of H2 for denitrification, the water exceeding 5 m 3 / h on the adjustment unit is adjusted to H2, and heterotrophic denitrification is performed by using the carbon source therein, at which the BOD / N ratio of the influent of H2 is about 2.72, so that no glucose is added, and the need for organic matter for denitrification can also be met. After the H2 / O2 unit, the total nitrogen of the biological effluent is reduced to 16-20 mg / L, which can meet the discharge requirements.

[0123] (5) The total retention time of the post-physical unit is about 10 h, the polyferric dosage is 72 L / h (slurry, density 1.58 g / cm 3 ), the activated carbon dosage is 24 kg / h, and the PAM dosage is 0.2 kg / h. After the post-physical treatment, the turbidity of the biological effluent is reduced from 750-800 NTU to below 5 NTU, and the COD is reduced from 200-240 mg / L to 100-120 mg / L.

[0124] (6) The dosage of sodium dihydrogen phosphate is 6.25 kg / h, which is added to the O1 and O2 units in a ratio of 2:1. The liquid alkali (mass concentration 30%) is intermittently added, and the dosage is about 145 kg / h, which is added to the O1 unit and the post-physical unit in a ratio of 7:3.

[0125] The COD, ammonia nitrogen and total nitrogen (TN) indexes of each unit are shown in Table 7.

[0126] Table 10 Main water quality indexes of each unit

[0127]

[0128] Note: L represents lower than the detection limit; N.D. represents not detected.

[0129] The effluent water after the post-chemical treatment meets the direct discharge limit value of the "Coke Chemical Industry Pollutant Discharge Standard" (GB 16171-2012) and the enterprise internal control standard, as shown in Table 8. Compared with the original water quality, the COD removal rate is higher than 96.0%, and the TN removal rate is higher than 93.3%, the removal rate is higher than 97.8%.

[0130] Table 11 Total effluent water quality indicators

[0131]

[0132] Note: L represents lower than the detection limit; N.D. represents not detected.

[0133] The estimated operating cost of the dual-chemical coupling O / H / H / O process is shown in Table 9. According to experience, labor costs and sludge treatment and disposal costs account for 10% and 5% of the total operating cost, but this time the labor costs and sludge treatment costs are not considered in the estimation and analysis. The water cost of the reagent is converted into the reagent cost, and the aeration energy cost is converted into the compressed air cost of 0.1 yuan / m 3 , the unit price of industrial electricity is 0.6 yuan / (kW·h), the price of ferrous sulfate heptahydrate is 300 yuan / ton, the price of anionic PAM is 8000 yuan / ton, the price of 30% caustic soda is 1400 yuan / ton, the price of industrial glucose is 1500 yuan / ton, the price of sodium dihydrogen phosphate is 4000 yuan / ton, the price of slurry state polyferric is 750 yuan / ton, and the price of powdered activated carbon (iodine adsorption value 600 mg / g) is 6000 yuan / ton.

[0134] The above-mentioned dual-chemical coupling O / H / H / O process, in which the most expensive operating units are the post-chemical treatment unit and the O1 unit, accounting for 43.3% and 31.6% of the total operating cost, respectively, the reagent cost accounts for 66.1% of the total cost, and the rest is the electricity consumption cost, in which the aeration electricity consumption accounts for 78.1% of the total electricity consumption. Compared with Example 3, due to the adjustment of the aeration amount of the O1 / O2 unit, the cost of gas consumption is reduced by 0.450 yuan / m 3 , due to the reduction of glucose, the reagent cost is reduced by 0.450 yuan / m 3 , and the total cost is reduced by 0.911 yuan / m 3 . The operating cost of the biological system is about 4.636 yuan / m 3 wastewater, which is lower than the operating cost of other processes of the same type.

[0135] Table 12 Partial operating cost estimation table Unit: yuan / m 3 wastewater

[0136]

[0137]

[0138] Example 5

[0139] The embodiment is directed to the biochemical process of coking wastewater treatment, and proposes a double-physicochemical coupling O / H / H / O biochemical process with high organic load and high denitrification efficiency. The O1 unit realizes efficient carbon removal and ammoniation / partial short-cut nitrification process, the H1 unit realizes anaerobic ammonium oxidation denitrification process, the H2 / O2 unit realizes heterotrophic denitrification deep denitrification process, and the O2 unit is also the guarantee of stable effluent water quality. In addition, the sludge separated by the post-physicochemical process is added to the pre-physicochemical unit to play the role of the remaining activated carbon, and also reduces the organic load and nitrogen-containing heterocyclic compounds of the biological influent, which can reduce the material consumption and energy consumption in the biological carbon removal and denitrification process. Specifically, the technical route of the embodiment 5 is as shown in Figure 9 .

[0140] (1) The raw water volume is about 55m 3 / h, the ferrous sulfate dosage of the pre-physicochemical process is 50 kg / h, and the PAM dosage is 0.04 kg / h. The pre-physicochemical process converts inorganic toxic ions such as cyanide, thiocyanide and sulfide into low-toxicity metal cyanide, metal thiocyanide and metal sulfide, part of which is removed from the water phase by precipitation, and part of which enters the biological system for complete degradation. After the pre-physicochemical unit, the cyanide is reduced from 10-20 mg / L to 1.0-1.5 mg / L, the sulfide is reduced from 30-40 mg / L to 5-8 mg / L, and the thiocyanide is converted into ferric thiocyanate, which greatly reduces the toxicity of the influent. On this basis, the post-physicochemical sludge containing unsaturated activated carbon is backflowed to the pre-physicochemical process, and the activated carbon dosage is 0.5 g / L. After the post-physicochemical process, the COD of the pre-physicochemical effluent can be further reduced by about 170-200 mg / L, which also includes part of the heterocyclic compounds, and the equivalent TN is reduced by about 5.5-10.0 mg / L.

[0141] (2) The biological influent water volume is about 55m 3 / h, which includes sludge filter filtrate and ground washing wastewater, etc. It enters the O1 unit to realize the state of circulating fluidization by air stirring and special structure, with a gas-water ratio of 12:1, an influent load of 1.1-1.3 kg-COD / m 3 / d, DO controlled at 1.0-1.5 mg / L, and pH controlled at 6.5-7.0. The COD is reduced from 2000-2400 mg / L to 600-800 mg / L, the ammonia nitrogen is increased from 50-70 mg / L to 62-72 mg / L, and the total nitrogen is reduced from 190-220 mg / L to 150-172 mg / L, of which the nitrite nitrogen is 85-100 mg / L, and the nitrosation rate is about 56%-58%, and there is no nitrate nitrogen.

[0142] (3) H1 unit influent contains a large amount of nitrite nitrogen and ammonia nitrogen, and the ratio thereof is controlled at about 1.37-1.38, at which the anaerobic ammonia oxidation process is realized under the condition of sufficient alkalinity by the anaerobic ammonia oxidation bacteria added in advance and attached to the H1 unit filler. The hydraulic retention time of the H1 unit is 30-40 h, DO is controlled at 0-0.2 mg / L, pH is maintained at 7.0-7.5, and total nitrogen is reduced from 150-172 mg / L to 25-30 mg / L.

[0143] (4) It is observed that the H1 effluent still contains 25-30 mg / L of total nitrogen, which is because about 0.26 mol of nitrate nitrogen is produced for each 1 mol of N2 produced in the anaerobic ammonia oxidation process. For this reason, the role of the H2 unit can ensure that the escaped nitrate nitrogen is further completely denitrified, and the complete nitrification role of the O2 unit can ensure that the O1 unit produces a proportion of NO2- that cannot completely undergo anaerobic ammonia oxidation due to water quality fluctuation. In order to meet the total nitrogen target, a reflux ratio of about 100% is set. In order to supplement the carbon source of H2 for denitrification, the water exceeding 5 m 3 / h on the adjustment unit is adjusted to H2, and heterotrophic denitrification is performed by using the carbon source therein, at which the BOD / N ratio of the H2 influent is about 2.72, so that no glucose is added, and the need for organic matter for denitrification can also be met. After the H2 / O2 unit, the total nitrogen of the biological effluent is reduced to 16-20 mg / L, which can already meet the discharge requirements.

[0144] (5) The total retention time of the post-physical unit is about 10 h, the poly-iron dosage is 72 L / h (slurry, density 1.58 g / cm 3 ), the activated carbon dosage is 24 kg / h, and the PAM dosage is 0.2 kg / h. After the post-physical treatment, the turbidity of the biological effluent is reduced from 750-800 NTU to below 5 NTU, and the COD is reduced from 200-240 mg / L to 100-120 mg / L.

[0145] (6) The post-physical sludge contains unsaturated activated carbon components, which can be used as adsorbents for the pre-physical treatment, play the adsorption capacity of the remaining activated carbon, reduce the influent load of the biological unit, and reduce the aeration amount and the dosage of materials. Because of the addition of the unsaturated activated carbon in the post-physical treatment, the phosphorus salt and alkali source of the biological system can be reduced to a certain extent. Specifically, the sodium dihydrogen phosphate dosage is reduced to 6.00 kg / h, and is added to the O1 and O2 units in a ratio of 2:1, respectively. The liquid caustic (mass concentration 30%) is intermittently added, and the dosage is reduced to about 120 kg / h, and is added to the O1 unit and the post-physical unit in a ratio of 7:3, respectively.

[0146] (7) In addition, it is found that the backflow of post-chemical sludge only changes the water quality indicators before the O1 unit, because the biological system of the process is very stable, and a small change in COD and reagents will not affect the operation of the entire system. Under the condition of meeting the biological requirements of phosphorus salt and alkali source, the process still has the space for energy saving and consumption reduction.

[0147] COD, ammonia nitrogen of each unit The total nitrogen (TN) index is shown in Table 10.

[0148] Table 13 Main water quality indicators of each unit

[0149]

[0150] Note: L represents lower than the detection limit; N.D. represents not detected.

[0151] The effluent, i.e. post-chemical effluent, meets the direct discharge limit value of “Coke Chemical Industry Pollutant Discharge Standard” (GB 16171-2012) and the enterprise internal control standard, as shown in Table 11. Compared with the original water quality, the COD removal rate is higher than 96.0%, the TN removal rate is higher than 93.3%, the ammonia nitrogen removal rate is higher than 97.8%, and the total phosphorus removal rate is higher than 97.8%.

[0152] The operation cost estimation of the double-chemical coupled O / H / H / O process is shown in Table 12. According to experience, labor cost and sludge treatment and disposal cost account for 10% and 5% of the total operation cost, but this estimation analysis does not consider labor cost and sludge treatment cost. The water fee of the configured reagents is converted into reagent cost, and the aeration energy cost is converted into compressed air cost of 0.1 yuan / m 3 , industrial electricity price 0.6 yuan / (kW·h), ferrous sulfate heptahydrate 300 yuan / ton, anionic PAM 8000 yuan / ton, 30% caustic soda 1400 yuan / ton, industrial glucose 1500 yuan / ton, sodium dihydrogen phosphate 4000 yuan / ton, slurry state polyferric chloride 750 yuan / ton, and powdered activated carbon (iodine adsorption value 600 mg / g) 6000 yuan / ton.

[0153] Table 14 Total effluent water quality indicators

[0154]

[0155] Note: L represents lower than the detection limit; N.D. represents not detected.

[0156] Table 15 Part of the operation cost estimation table Unit: yuan / m 3 Waste water

[0157]

[0158] ​The above-mentioned process based on double-physicochemical coupling O / H / H / O, wherein the most costly operating units are the post-physicochemical unit and the O1 unit, accounting for 44.0% and 29.9% of the total operating cost, respectively, the reagent cost accounts for 64.7% of the total cost, and the rest is the power consumption cost, wherein the aeration power consumption accounts for 78.1% of the total power consumption. Compared with the implementation case 4, the backflow of the unsaturated activated carbon in the post-physicochemical unit reduces the biological raw water organic load and nitrogen load reagent cost by 0.392 yuan / m 3 , and the total cost is also reduced by 0.392 yuan / m 3 . The operating cost of the double-physicochemical coupling O / H / H / O process in this implementation case is about 8.942 yuan / m 3 of wastewater, which is lower than the operating cost of other processes of the same type.

[0159] In summary, the double-physicochemical coupling O / H / H / O process proposed in the present application has the characteristics of high organic load, multiple denitrification modes, high denitrification efficiency, and low operating cost, and is suitable for, but not limited to, industrial wastewater with high toxicity, high pollution load, and rich in nitrogen and sulfur but lacking in phosphorus. The tail water treated by the system meets the inlet requirements of advanced treatment, and further achieves the purpose of water reuse, Figure 10 The appearance of the water at each stage can be observed, and it can be observed that the system has obviously removed the color and turbidity, and has been greatly improved in the sense. According to the calculation, under the optimal operating conditions, taking the total inflow of 60 m 3 / h of coking wastewater as the basis, the operating cost of the double-physicochemical coupling O / H / H / O process is about 4.7 million yuan / year, which is 2.58 million yuan / year less than before the reconstruction; the COD reduction amount is 1780 tons / year, which is 100 tons / year more than before the reconstruction; and the TN reduction amount is 150 tons / year, which is 30 tons / year more than before the reconstruction. If the current national coking wastewater volume is 2.6 million tons / year, the operating cost can be saved by 128 million yuan / year, the pollutant reduction space is 49500 tons-COD / year, and 14900 tons-TN / year.

[0160] The above-mentioned is only the preferred implementation mode of the present application, including the new construction and expansion project of the double-physicochemical coupling O / H / H / O, but the protection scope of the present application is not limited thereto, wherein the expansion project is not only suitable for the A / A / O process, but also suitable for the commonly used biological processes such as A / O / O, A / O / A / O, A / A / O / O, and the coupling of MBR, MBBR, SBR technology, and other related biological processes, and even any changes or replacements that can be easily thought of by those skilled in the technical field within the technical range disclosed in the present application should be covered within the protection scope of the present application.

Claims

1. A dual physicochemical coupling O / H / H / O integrated process for treating typical industrial wastewater, comprising a pre-physicochemical unit (1), a water collection and conditioning unit (2), a carbon removal and ammonia oxidation aerobic unit O1 (3), a hydrolysis-coupled denitrification unit H1 (4), a hydrolysis-heterotrophic denitrification unit H2 (5), a complete nitrification aerobic unit O2 (6), and a post-physicochemical unit (7), wherein the units are connected sequentially; wherein, FeSO4 is added to the pre-physicochemical unit (1) to obtain a mixed electron donor, which is then added to the H1 unit to drive denitrification. The unsaturated activated carbon sludge obtained from the post-physicochemical unit is returned to the pre-physicochemical unit (1) to utilize the remaining adsorption capacity of the activated carbon and reduce the organic load of the influent to the biological unit. The equalization tank unit homogenizes and equalizes the influent, and then pushes a portion of the regulated wastewater through H2 to drive denitrification. The O2 unit is equipped with a nitrification liquor reflux system to handle NH4 in H1 or H2. + Special operating conditions where -N concentration exceeds the standard; The O1 unit drives different nitrogen metabolism stages through aeration, phosphorus source and liquid alkali addition; the mixed electron donor is ferrous sulfide (FeS), iron sulfide (Fe2S3) and Prussian blue (Fe4[Fe(CN)6]3) precipitate; The aerobic unit O1 (3) for carbon removal and ammonia oxidation includes an O1 unit rising zone (3-1) and an O1 unit falling zone (3-2), which are separated by an O1 unit guide tube (3-3); the hydrolysis-coupled denitrification unit H1 (4) includes a mixing zone (4-1) and a packing zone (4-2); the hydrolysis-heterotrophic denitrification unit H2 (5) includes a reaction zone (5-1) and a separation zone (5-2); the fully nitrified aerobic unit O2 (6) includes an O2 unit rising zone (6-1) and an O2 unit falling zone (6-2), which are separated by an O2 unit guide tube (6-3); The hydraulic retention time of the O1 unit is 50-60 h, the air-to-water ratio is 12:1-20:1, the dissolved oxygen (DO) value is controlled within the range of 1-2 mg / L, the pH value is controlled between 6.5 and 7.5, and the organic loading is 0.8-1.2 kg-COD / m³. 3 / d; The hydraulic retention time of the hydrolysis-coupled denitrification unit H1(4) is 30-40 h, the DO is controlled within the range of 0-0.2 mg / L, the denitrification efficiency is higher than 88%, and the denitrification load reaches 0.10-0.12 kg-N / m³. 3 / d; The hydraulic retention time of the hydrolysis-heterotrophic denitrification unit H2(5) is 25~30 h, the DO is controlled in the range of 0~0.5 mg / L, and the total nitrogen removal rate reaches more than 90%. The hydraulic retention time of the fully nitrifying aerobic unit O2(6) is 50-60 h, the DO is controlled above 3 mg / L, and the pH value is controlled above 7.5; For existing AAO processes, add an aerobic tank before the two A tanks, and selectively cancel or modify the reflux system; for existing AOO processes, add one or two hydrolysis tanks between the two O tanks, and place the original A tank after the first aerobic tank or use it as a carbon source management unit before the aerobic tank.

2. The application of the process described in claim 1, characterized in that, The carbon source management and substrate application include bioavailable reducing inorganic substances, including metal cyanides, metal thiocyanates, and metal sulfides; through adsorption, coagulation, flotation, extraction, and redox operations in the pre-physicochemical unit, available organic and inorganic electron donors in the raw water are separated for denitrification in the H unit.

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