Coprocessing system for refractory organic wastewater in industrial park

Abstract

The invention relates to the technical field of sewage treatment, in particular to a cooperative treatment system for degradation-resistant organic wastewater in an industrial park. High-salt, high-concentration organic and high-toxicity wastewater in a fine chemical industry park is treated, oil removal, hardness removal and removal of suspended solids and part of organic matters are achieved through the pretreatment system in the process, the wastewater passing through the pretreatment system is desalted through the evaporation system, and the wastewater passing through the evaporation system is recycled. More energy is saved in the process, and scaling of equipment can be effectively avoided; a condensate obtained by evaporation is subjected to adsorption separation and oxidation to obtain wastewater suitable for biochemical treatment, and COD, nitrogen and phosphorus in the wastewater are further removed through biochemical treatment, so that sewage treatment and up-to-standard discharge are realized. The system disclosed by the invention can realize treatment and up-to-standard discharge of high-salt, high-concentration organic and high-toxicity wastewater in the industrial park, is high in integration degree in the process and wide in wastewater adaptability, and has wide application and popularization prospects.

Description

Technical Field

[0001] The present invention relates to the technical field of sewage treatment, and in particular to a collaborative treatment system for refractory organic wastewater in industrial parks. Background Art

[0002] The fine chemical industry plays a vital role in my country's national economy. Currently, my country leads the world in fine chemical production capacity, output, and export volume. However, the environmental pollution caused by the fine chemical industry cannot be ignored. Firstly, the raw materials used in fine chemical production are mostly organic toxins such as chlorinated and brominated hydrocarbons, aromatic compounds, alcohols, acids, and ketones. These substances are highly toxic and difficult to degrade, making them susceptible to environmental pollution. Secondly, the fine chemical production process is complex, requiring multiple reactions to produce the desired product. This results in the discharge of large amounts of raw materials, intermediates, and by-products as "three wastes." Among these, discharged production wastewater has the most significant impact on the environment. Research has found that this type of wastewater has a complex composition, is highly toxic, and is difficult to degrade. Furthermore, the wastewater has a high salt content, high color, and poor biodegradability, making it one of the most difficult industrial wastewaters to treat. Not only that, the compounds contained in wastewater ("three-hazard" compounds, non-biodegradable substances or bioinhibitors) have specific physiological toxicity, persistence and bioaccumulation, and can accumulate in organisms at extremely low concentrations, thus causing serious harm to the ecosystem and human health.

[0003] High-salt, high-concentration organic, and highly toxic wastewater from the fine chemical industry has complex composition and poor biodegradability, making it difficult and costly to treat. This presents significant environmental and safety risks and is a bottleneck hindering the sustainable development of the fine chemical industry. Treatment technologies for high-salt, high-concentration organic, and highly toxic wastewater have attracted considerable attention as both a hot and challenging area in industrial wastewater treatment. High-salt wastewater generally refers to wastewater with a total salt content (measured as NaCl) of at least 1%, and is widely found in industries such as papermaking, chemicals, coal, pharmaceuticals, leather, and textile printing and dyeing. These wastewaters often contain high levels of organic pollutants and large amounts of soluble inorganic salts, presenting numerous challenges to wastewater treatment. High concentrations of inorganic salts can inhibit or even toxic microbial growth. Under high osmotic pressure, the activity of various enzymes inside and outside cells is reduced by salting out. Excessive osmotic pressure can also cause cellular dehydration, and in severe cases, plasmolysis and even microbial inactivation. Consequently, the application of traditional biological treatment methods has been significantly limited. Wastewater from production processes such as pharmaceuticals, chemicals, and printing and dyeing often retains impurities from raw materials, products, and by-products, making it highly toxic and difficult to degrade. Furthermore, due to differences in processes and requirements across various industries, wastewater composition is complex, properties vary widely, and pollutant concentrations and volumes fluctuate, impacting normal process operation and making it difficult for water quality to meet discharge standards.

[0004] Irrational discharge or incomplete treatment of high-salt, high-concentration organic, and highly toxic wastewater will harm the ecological environment. Direct discharge into water bodies will damage the aquatic ecosystem and affect the normal growth and reproduction of plants and animals. If it seeps into the soil, it will cause salinization, seriously polluting surface water and groundwater, and ultimately posing a threat to human health. Therefore, there is an urgent need to harmlessly treat wastewater. Compared with the traditional chemical industry, the fine chemical industry has a smaller production scale, a wider variety of raw materials, diverse production processes, and produces wastewater with excessively high salt and organic content and complex compositional characteristics. This poses new challenges to the wastewater adaptability, flexibility, and integration of treatment technologies, and is also the future development trend of harmless treatment of high-salt, high-concentration organic, and highly toxic wastewater in the fine chemical industry. Summary of the Invention

[0005] The purpose of the present invention is to provide a collaborative treatment system for difficult-to-degrade organic wastewater in industrial parks, so as to achieve comprehensive and stable treatment of high-salt, high-concentration organic and highly toxic wastewater, thereby achieving the purpose of resource conservation while achieving wastewater treatment.

[0006] To achieve the above-mentioned object, the present invention adopts the following technical solution: a coordinated treatment system for refractory organic wastewater in industrial parks, comprising a pretreatment system, an evaporation system, an adsorption separation system, an advanced oxidation system, a biochemical treatment system, a waste salt treatment system, and an exhaust gas treatment system;

[0007] The pretreatment system includes a regulating tank. The effluent from the regulating tank is fed through an air flotation and iron-carbon micro-electrolysis device and then to an evaporation system. During the air flotation stage, in addition to adding flocculants and coagulants, soluble phosphates and activated carbon powder are also added to the air flotation machine. An iron-carbon composite layer is provided in the iron-carbon micro-electrolysis device.

[0008] The evaporation system is a two-stage multiphase flow MVR negative pressure evaporation system, comprising two MVR evaporators connected in series, the first stage being a conventional MVR evaporator and the second stage being a multiphase flow MVR evaporator; the multiphase flow MVR evaporator is filled with ceramic solid particles; the evaporated mother liquor obtained by the multiphase flow MVR evaporator is desalinated by thermal drying; the waste salt produced by desalination is treated by a waste salt treatment system, and the resulting carbon slag is used as filler for the iron-carbon composite layer and raw material for the ceramic solid particles; the condensate obtained by the two-stage MVR evaporators is sent to an adsorption separation system;

[0009] The effluent from the adsorption separation system is sent to the advanced oxidation system, and the adsorption separation system and the advanced oxidation system further remove COD and toxic substances in the condensate. The effluent from the advanced oxidation system is sent to the biochemical treatment system, and is discharged or reused after being treated by the biochemical treatment system.

[0010] The waste gas treatment system treats the waste gas generated during the treatment process and then discharges it.

[0011] Furthermore, the regulating tank is provided with multiple, and the effluent of the regulating tank is sequentially passed through the first flotation machine, the iron-carbon micro-electrolysis device, and the second flotation machine before being sent to the evaporation system; the first flotation machine and the second flotation machine are each provided with at least one; the soluble phosphate includes sodium phosphate, which is metered and added according to the concentration of scale-forming ions in the flotation machine inlet water, and the addition amount is 1.2 to 1.5 times the theoretical addition amount; the particle size of the activated carbon micropowder is 50 to 100 μm, and the addition amount is 10 to 50 g / m 3 Water is entering the flotation machine.

[0012] Furthermore, the iron-carbon micro-electrolysis device is provided with multiple layers of fillers, which are, from top to bottom, a filter material layer, an iron-carbon composite layer and a gravel layer; the filter material layer includes an activated carbon layer; the iron-carbon composite layer is a composite layer of iron and carbon, wherein the mass ratio of iron to carbon is 1:1, the iron is iron filings, 1 to 3 cm long, 0.5 to 1 cm wide, and 0.1 to 0.5 cm thick; and the carbon is carbon slag.

[0013] Furthermore, scale inhibitors are added to both MVR evaporators; based on the water flow rate of the MVR evaporator, the amount of scale inhibitor added is 10 to 50 g / m 3 The scale inhibitor comprises, by weight, 10-30% diethanolamine, 1-5% sodium polyepoxysuccinate, 5-10% carbonyl disulfide, 10-20% sodium dodecylbenzenesulfonate, 1-5% polyacrylamide, 10-20% polyether-modified polysiloxane defoamer, and the balance water. Ceramic solid particles are added to the second-stage multiphase flow MVR evaporator. The ceramic solid particles are prepared by mixing carbon slag powder, iron powder, manganese ore powder, a pore-forming agent, and a binder, granulating, drying, sintering under inert gas protection, and cooling. The mass ratio of carbon slag powder, iron powder, manganese ore powder, pore-forming agent and binder is carbon slag powder: iron powder: manganese ore powder: pore-forming agent: binder = 5-10:5-10:10-30:1-3:5-15; the carbon slag powder, iron powder and manganese ore powder are all sieved through 200-400 mesh; the granulation particle size is 3-10 mm; the pore-forming agent includes perlite powder (commercially available, 100 mesh); the binder includes 20 wt.% sodium silicate solution; the firing temperature is 1000-1200° C., and the firing time is 10-30 min.

[0014] Furthermore, the desalination is achieved by spray drying, and the waste gas generated by spray drying is sent to the waste gas treatment system. Waste salt is obtained during the treatment process of spray drying and the waste gas generated by spray drying. The waste salt is treated by the waste salt treatment system. In the waste salt treatment system, the waste salt is subjected to anaerobic pyrolysis, redissolution, decarbonization and MVR salt separation process to obtain industrial salt, thereby realizing comprehensive treatment of waste salt and decarbonizing to obtain carbon slag.

[0015] Furthermore, the adsorption separation system is a molecular sieve adsorption tower filled with 4A molecular sieve filler. After the adsorption separation system is saturated with adsorption, high-temperature steam is used for desorption. The desorption steam is condensed to obtain a desorption condensate, which is mixed with the evaporated mother liquor. The advanced oxidation system is an ozone catalytic oxidation system. The biochemical treatment system includes a multi-stage hydrolysis acidification, a UASB anaerobic tower, a modified CLR tank, a secondary sedimentation tank and an MBR tank connected in sequence.

[0016] Furthermore, the waste gas generated by the pretreatment system and the evaporation system goes to the waste gas treatment system I; the waste gas generated by the thermal drying and waste salt treatment system goes to the waste gas treatment system II; and the waste gas generated by the advanced oxidation system and the biochemical treatment system goes to the waste gas treatment system III.

[0017] Furthermore, the waste gas treatment system I is a high-concentration organic waste gas treatment system, which includes water washing, acid washing absorption, alkaline washing absorption, water washing, multi-phase catalytic oxidation, water washing, electrocatalytic oxidation, and then high-altitude discharge; the waste gas treatment system II is a high-temperature waste gas treatment system, which includes cyclone dust removal, primary water washing, secondary water washing, acid washing absorption, alkaline washing absorption, water washing, multi-phase catalytic oxidation, water washing, electrocatalytic oxidation, and then high-altitude discharge; the waste gas treatment system III is a low-concentration organic waste gas treatment system, which includes acid washing absorption, alkaline washing absorption, water washing and biological filter, and then high-altitude discharge.

[0018] Furthermore, the biofilter is provided with fillers, which include a plastic shell and ceramic solid particles filled in the plastic shell.

[0019] Furthermore, the wastewater generated in the water washing step is all sent to the front end of the biochemical treatment system, the wastewater generated in the acid washing absorption and alkaline washing absorption steps is all sent to the regulating tank in the pretreatment system, the wastewater generated in the heterogeneous catalytic oxidation step is all sent to the front end of the advanced oxidation system, and the wastewater generated in the electrocatalytic oxidation step is all sent to the front end of the biochemical treatment system.

[0020] Beneficial effects of the present invention:

[0021] 1. The present invention can achieve comprehensive treatment of high-salt, high-concentration organic, and highly toxic wastewater in industrial parks. The system has high system integration and wide adaptability. It can achieve wastewater treatment while being more energy-efficient and easy to promote and apply.

[0022] 2. The pretreatment process of the present invention can ensure the stable operation of the system on the one hand, and can achieve the comprehensive removal of oil, hardness and suspended solids in the wastewater on the other hand. At the same time, through the iron-carbon micro-electrolysis device, it can also achieve the degradation of some organic matter in the wastewater and the removal of toxicity, which plays a positive and beneficial role in the subsequent stable operation of the system;

[0023] 3. The present invention realizes evaporation and desalination of wastewater through a two-stage multiphase flow MVR negative pressure evaporation system, which is more energy-saving and efficient. One stage adopts ordinary MVR negative pressure evaporation, and the second stage adopts multiphase flow MVR negative pressure evaporation, which can effectively avoid scaling and ensure the stable operation of the system.

[0024] 4. The present invention further removes COD and toxic substances in wastewater through an adsorption separation system and an advanced oxidation system, thereby meeting the subsequent biochemical treatment requirements, ultimately achieving standard discharge of sewage and completing the wastewater treatment process;

[0025] 5. The system of the present invention collects and treats the waste gas generated during the production process, effectively avoiding the pollution of the environment caused by the organic waste gas generated during the treatment process, and realizing environmental protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the process flow of the system of the present invention;

[0027] Figure 2 It is a schematic diagram of the process flow of the pretreatment system of the present invention;

[0028] Figure 3 Schematic diagram of the structure of the iron-carbon micro-electrolysis device of the present invention;

[0029] Figure 4 This invention relates to a schematic diagram of the principle of an existing MVR evaporation system;

[0030] Figure 5 This is a schematic diagram of the process flow of the waste gas treatment system I of the present invention;

[0031] Figure 6 This is a schematic diagram of the process flow of the waste gas treatment system II of the present invention;

[0032] Figure 7 This is a schematic diagram of the process flow of the waste salt treatment system of the present invention;

[0033] Figure 8 It is a process flow diagram of the biochemical treatment system of the present invention;

[0034] Figure 9 This is a schematic diagram of the process flow of the waste gas treatment system III of the present invention;

[0035] Figure 10 The present invention relates to a schematic diagram of an existing plastic shell structure

[0036] Figure 11 This is a comparison diagram of the MVR evaporator status before and after the anti-scaling measures of the present invention.

[0037] The names corresponding to the marks in the figure are:

[0038] 1. Iron-carbon micro-electrolysis device; 11. Filter material layer; 12. Iron-carbon composite layer; 13. Gravel layer; 2. MVR evaporation system; 21. MVR evaporator; 22. Circulation pump; 23. Heat exchanger; 24. Compressor; 25. Condenser; 3. Plastic casing. DETAILED DESCRIPTION

[0039] The technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0040] like Figure 1 As shown, the high-salt, high-concentration organic, and highly toxic wastewater from the fine chemical park is sent to the two-stage multiphase flow MVR negative pressure evaporation system for evaporation after pretreatment. The waste gas generated by the pretreatment system and the two-stage multiphase flow MVR negative pressure evaporation system is treated by the waste gas treatment system I; the mother liquor generated by the evaporation system is thermally dried to obtain waste salt and waste gas, the waste salt is separated by the waste salt treatment system, and the waste gas is treated by the waste gas treatment system II.

[0041] The condensate produced by the two-stage multiphase flow MVR negative pressure evaporation system is sent to the advanced oxidation system after passing through the adsorption separation system. After the adsorption separation system is saturated with adsorption, steam high-temperature desorption is adopted. The desorption condensate produced by desorption is mixed with the evaporation mother liquor and then treated by thermal drying.

[0042] The effluent from the advanced oxidation system is sent to the biochemical treatment system. The effluent from the biochemical treatment system is discharged or reused after meeting the standards. The odor generated by the advanced oxidation system and the biochemical treatment system is treated by the waste gas treatment system III.

[0043] like Figure 2-3 As shown, high-salt, high-concentration organic, and highly toxic wastewater passes through a regulating tank and then goes to an air flotation machine. There are multiple regulating tanks for balancing flow, regulating water quality, and buffering, so that the water quality and amount entering the system are stable, ensuring the stable operation of the system. The air flotation machine includes a first air flotation machine and a second air flotation machine. Both the first air flotation machine and the second air flotation machine can be provided with multiple. When flocculant PAM and coagulant PAC are added to the air flotation machine, soluble phosphates such as sodium phosphate and activated carbon powder are also added, so that hardness can be removed while removing oil and suspended solids by flotation. Soluble phosphates include sodium phosphate, which is added in a metered amount according to the concentration of scale-forming ions in the water entering the air flotation machine, and the addition amount is 1.2 to 1.5 times the theoretical addition amount. The particle size of the activated carbon powder is 50 to 100 μm, and the addition amount is 10 to 50 g / m 3 Water is entering the flotation machine.

[0044] An iron-carbon micro-electrolysis device 1 is installed between the first and second air flotation machines. The iron-carbon micro-electrolysis device 1 partially removes COD, ammonia nitrogen and toxic substances in the wastewater, which is more conducive to subsequent treatment. The addition of activated carbon powder, soluble phosphate and the iron-carbon micro-electrolysis device 1 helps to improve the removal effect of oil, suspended matter and hardness. The scum discharged by the air flotation machine is rich in organic matter and nitrogen and phosphorus, and can be used as fertilizer for comprehensive utilization.

[0045] The iron-carbon micro-electrolysis device 1 has water inlet from the top and outlet from the bottom; from top to bottom, the device comprises a filter layer 11, an iron-carbon composite layer 12 (a mixture of carbon slag and iron powder at the rear end), and a gravel layer 13, wherein the filter layer 11 includes an activated carbon layer, etc.; in the iron-carbon composite layer 12, the mass ratio of iron to carbon is 1:1, the iron is iron filings, 1 to 3 cm long, 0.5 to 1 cm wide, and 0.1 to 0.5 cm thick; the carbon is carbon slag.

[0046] like Figure 1 、 4 As shown in FIG-7 , the effluent from the pretreatment system enters the MVR evaporation system 2 from the front end of the circulation pump 22, and then the material and the circulating material are transported to the heat exchanger 23 through the circulation pump 22, and then transported to the MVR evaporator 21 after heat exchange, where they boil and evaporate while flowing downward, generating secondary steam at the top of the MVR evaporator 21. At the bottom of the MVR evaporator 21, the material becomes a concentrated liquid, part of which is discharged and part enters the circulation; the secondary steam is transported to the compressor 24 after defoaming at the top of the MVR evaporator 21, and the compressor 24 compresses the secondary steam as heating steam, which is transported to the heat exchanger 23 to heat the material and the circulating material. The secondary steam is transported to the condenser 25 through the heat exchanger 23, where it is condensed to obtain condensate, thereby realizing a continuous evaporation process.

[0047] In the present invention, a two-stage multiphase flow MVR negative pressure evaporation system is adopted, in which two MVR evaporators 21 are connected in series. The first stage is an ordinary MVR evaporator 21, which is used for the preliminary concentration of the effluent material of the pretreatment system. The second stage is a multiphase flow MVR evaporator 21. The concentrated liquid produced by the first stage MVR evaporator 21 is used as the feed of the second stage multiphase flow MVR evaporator 21, which is used to further concentrate the wastewater after the first stage concentration; the evaporated mother liquor obtained after the second stage concentration is sent to thermal drying, and the condensate obtained by the first and second stage concentrations is mixed and sent to the adsorption separation system.

[0048] In the present invention, a scale inhibitor is added to the first-stage MVR evaporator 21, and a scale inhibitor and ceramic solid particles are added to the second-stage multiphase flow MVR evaporator 21. A multiphase flow state of evaporation mother liquor and ceramic solid particles is formed in the second-stage multiphase flow MVR evaporator 21, thereby improving concentration efficiency on the one hand and preventing equipment scaling on the other hand, ensuring equipment stability and service life. The scale inhibitor is an organic phosphorus-free scale inhibitor, which includes, by percentage, 10-30% diethanolamine, 1-5% sodium polyepoxysuccinate, 5-10% carbonyl dihydrazine, 10-20% sodium dodecylbenzene sulfonate, 1-5% polyacrylamide, 10-20% polyether-modified polysiloxane defoamer, and the balance is water. The components are commercially available, the molecular weight of the sodium polyepoxysuccinate is 400-1500, and the model of the polyether-modified polysiloxane defoamer is RianPont8405.

[0049] For ceramic solid particles, carbon slag powder, iron powder, manganese ore powder, pore-forming agent and binder are mixed, granulated and dried, sintered under inert gas protection, and cooled to obtain the obtained particles; wherein the mass ratio of carbon slag powder, iron powder, manganese ore powder, pore-forming agent and binder is: carbon slag powder: iron powder: manganese ore powder: pore-forming agent: binder = 5-10:5-10:10-30:1-3:5-15; the pore-forming agent is perlite powder, and the binder is 20wt.% sodium silicate solution; the carbon slag powder, iron powder and manganese ore powder are all sieved through 200-400 mesh sieves, and small balls with a particle size of 3-10 mm are prepared in the process. Under a protective atmosphere, such as nitrogen, argon, etc., at 1000-1200°C, the sintering can be completed for 10-30 minutes; the ceramic solid particles are in a fluidized state in the multiphase flow MVR evaporator 21.

[0050] The waste gas generated by the pretreatment system (including the waste gas generated by the conditioning tank, the flotation machine and the iron-carbon micro-electrolysis device 1, which is collected by the exhaust system) and the waste gas generated by the two-stage MVR evaporator 21 (non-condensable gas after condensation by the condenser 25) are transported to the waste gas treatment system I for treatment; the pretreatment system and the two-stage multiphase flow MVR negative pressure evaporation system generate high-concentration organic waste gas, which is discharged into the air after water washing, acid absorption, alkaline absorption, water washing, multiphase catalytic oxidation, water washing, and electrocatalytic oxidation in sequence; among them, the cleaning wastewater generated by the water washing section is sent to the back-end biochemical treatment system for treatment; the wastewater generated by acid absorption and alkaline absorption is sent to the regulating tank in the pretreatment system; the wastewater generated by multiphase catalytic oxidation is sent to the advanced oxidation system; the wastewater generated by electrocatalytic oxidation is sent to the biochemical treatment system; and the cleaning water in the above process comes from the reuse of the effluent from the biochemical treatment system; the multiphase catalytic oxidation and electrocatalytic oxidation in the process are existing mature processes and will not be repeated.

[0051] For thermal drying, spray drying is used. The material to be dried is sprayed into the drying chamber through a nozzle. At the same time, hot air is supplied to the drying chamber to make the droplets evaporate rapidly in the chamber and form a powdery substance. When the thermal drying is completed, the powder in the drying chamber needs to be collected. The thermal drying furnace produces a large amount of dust-containing flue gas, which enters the waste gas treatment system II (high-temperature organic waste gas) for waste gas treatment and is discharged after the treatment meets the standards. The waste salt generated in the process is treated by the waste salt treatment system.

[0052] For waste gas treatment system II, high-temperature waste gas is discharged into the air after cyclone dust removal, primary water washing, secondary water washing, acid absorption, alkaline absorption, water washing, heterogeneous catalytic oxidation, water washing, and electrocatalytic oxidation. Among them, cyclone dust removal obtains waste salt; the cleaning wastewater generated by the water washing section is sent to the back-end biochemical treatment system for treatment; the wastewater generated by acid absorption and alkaline absorption is sent to the regulating tank in the pretreatment system; the wastewater generated by heterogeneous catalytic oxidation is sent to the advanced oxidation system; the wastewater generated by electrocatalytic oxidation is sent to the biochemical treatment system; and the cleaning water in the above process comes from the reuse of the effluent from the biochemical treatment system; the heterogeneous catalytic oxidation and electrocatalytic oxidation in the process are existing mature processes and will not be described in detail.

[0053] For waste salt, the tail gas obtained after high-temperature pyrolysis is sent to the waste gas treatment system II (high-temperature organic waste gas) for waste gas treatment. The product after pyrolysis is dissolved for the second time and then filtered to obtain carbon slag. The carbon slag is crushed and sieved to obtain carbon slag powder. The carbon slag powder is used to prepare the above-mentioned ceramic solid particles. The obtained filtrate is separated by MVR salt separation process to obtain industrial salt, realizing resource recycling. The wastewater generated at the same time is sent to the biochemical system.

[0054] like Figure 1 As shown in Figures 8-10, the condensate produced by the evaporation system goes to the adsorption separation system. The adsorption separation system is a molecular sieve adsorption tower filled with 4A molecular sieve. The organic matter in the condensate is further adsorbed and removed by the molecular sieve adsorption tower. During the process, multiple groups of molecular sieve adsorption towers can be set up, with two in each group. When one of them is in the adsorption state, the other can be in the desorption state. High-temperature steam can be used for desorption. The steam after desorption is condensed, and the resulting condensate can be mixed with the aforementioned evaporation mother liquor, and then enters thermal drying.

[0055] The effluent from the adsorption separation system is further treated by the advanced oxidation system, which, on the one hand, further removes organic matter, and on the other hand, further removes harmful substances, reduces the organic load of the back-end biochemical system, and avoids poisoning to microorganisms; in the present invention, an ozone catalytic oxidation process is adopted, and the odor generated in the process is sent to the waste gas treatment system III (low-concentration organic waste gas) for treatment.

[0056] The effluent from the advanced oxidation system is sent to the biochemical system for final treatment and upgrading. The biochemical treatment system of the present invention comprises, in sequence, multi-stage hydrolysis and acidification, UASB anaerobic tower, improved CLR tank, secondary sedimentation tank and MBR tank; the above reactors are all existing mature reactors, among which hydrolysis and acidification is a pretreatment unit. The hydrolysis (acidification) treatment method is a method between aerobic and anaerobic treatment methods. The hydrolysis stage is a necessary process for the degradation of large molecular organic matter. If large molecular organic matter wants to be utilized by microorganisms, it must first be hydrolyzed into small molecular organic matter so that it can enter the bacterial cells for further degradation. The acidification stage is an accelerated process for the degradation of organic matter because it further converts the hydrolyzed small molecular organic matter into simple compounds and secretes them outside the cells; the UASB anaerobic The oxygen tower is an upflow anaerobic sludge blanket reactor, and its core principle is to use anaerobic microorganisms to degrade organic matter in wastewater under an oxygen-free environment; the modified CLR is a variation of the activated sludge process, which uses a directionally controlled aeration and stirring device. The sewage enters the oxidation ditch and is fully mixed with the activated sludge, and then the aeration device generates aeration through the specific positioning effect, so that the sewage and sludge are suspended in a closed channel and circulate continuously. The sludge is further fully mixed with the sewage during the circulation, and the microorganisms and organic matter fully react to purify the sewage; MBR is an advanced biofilm reactor technology that combines biological treatment and membrane separation technology. It uses microporous or ultrafiltration membranes as solid-liquid separation devices to achieve efficient purification of wastewater and separation of suspended matter.

[0057] The principle of the biochemical treatment system is as follows: the effluent from the advanced anaerobic system first enters a multi-stage hydrolysis and acidification process, where the biodegradability and carbon-nitrogen ratio of the sewage are improved and part of the COD in the sewage is removed; the effluent then enters the UASB anaerobic reactor for anaerobic reaction. The UASB consists of a sludge reaction zone, a gas-liquid-solid three-phase separator (including a sedimentation zone), and an air chamber. Its basic feature is that it can form granular sludge with good settling performance without the need for an adsorption carrier, maintaining a high concentration of microorganisms in the reactor, and thus can withstand a higher COD load, with a COD removal rate of over 90%. The equipment is simple, easy to operate, and free of clogging issues. After anaerobic reaction, the wastewater enters the modified CLR, a variation of the activated sludge process. Using a directionally controlled aeration and agitation device, the anaerobic wastewater enters the oxidation ditch, where it is thoroughly mixed with the activated sludge. The aeration system's specific positioning creates aeration, allowing the wastewater and sludge to circulate in a suspended state within the closed channel. During this cycle, the sludge further mixes with the wastewater, allowing microorganisms to react with organic matter, resulting in a purified wastewater. Due to the delayed aeration used in the modified CLR, the dissolved oxygen concentration in the oxidation ditch is high near the aeration device. As the water flows, the dissolved oxygen concentration in the water gradually decreases. Multiple aeration devices in an oxidation ditch create multiple aerobic-anaerobic alternations, creating conditions for short-term nitrification, short-term denitrification, and short-term nitrification-coupled anaerobic ammonium oxidation reactions in the activated sludge.

[0058] Conventional nitrification and denitrification occur simultaneously within the oxidation ditch. Short-cut nitrification coupled with anaerobic ammonium oxidation (ANAMMOX) denitrification improves the system's COD removal and denitrification efficiencies, while saving aeration energy and carbon source dosage, reducing operating costs. Short-cut nitrification is the foundation of the ANAMMOX process. It only oxidizes half of the ammonia into nitrite, saving 62.5% of oxygen and 50% of alkali consumption compared to full-cut nitrification.

[0059] After the wastewater is treated in the oxidation ditch, COD, ammonia nitrogen and total nitrogen are effectively removed, and then it enters the secondary sedimentation tank. The function of the secondary sedimentation tank is to separate mud and water. The suspended particles with a density greater than that of water are removed from the water by gravity sedimentation, so that the mixed liquid is clarified. The clarified liquid enters the MBR for further deep treatment, and the treated wastewater meets the discharge standards or is reused; most of the precipitated sludge is returned to the improved CLR after concentration, and a part is discharged as residual sludge. After dehydration, it is dried using the heat of the high-temperature exhaust gas in the thermal drying to achieve sludge reduction.

[0060] For waste gas treatment system III, low-concentration organic waste gas is discharged into the air after being sequentially absorbed by acid washing, absorbed by alkali washing, washed, and biofiltered. The waste liquid generated by acid washing and alkali washing is sent to the regulating tank in the pretreatment system, and the drainage of water washing and biofilter is sent to the biochemical treatment system. The biofilter uses filler as a carrier and aerates the inside of the filter to grow a large number of biofilms on the surface of the filter material. When sewage flows through, the high concentration of active microorganisms in the biofilm attached to the filter material and the small particle size of the filter material are used to give full play to the strong oxidative decomposition effect. The biological metabolism of microorganisms, biological flocculation, physical adsorption and interception of biofilm and filler, and the hierarchical predation of the food chain along the water flow direction in the reactor achieve efficient removal of pollutants. At the same time, the existence of aerobic and anoxic areas in the reactor is utilized to achieve the functions of denitrification and phosphorus removal. In the present invention, the filler in the biological filter is a commercially available plastic shell 3 (PVC material, overall spherical, cage-shaped made of criss-cross plastic strips, the upper and lower parts are buckled together, and the inside and outside are connected through through holes), and the above-mentioned ceramic solid particles are filled inside.

[0061] At the same time, if Figure 11 As shown, during operation, no ceramic solid particles are added to the second-stage multiphase flow MVR evaporator 21 of the evaporation system. After a period of time, obvious scaling occurs on the inner wall of the evaporator.

[0062] The system of the present invention involves many existing mature processes, which are not elaborated in detail in the present invention, but are not difficult to understand for those skilled in the art, so they are not described in detail.

[0063] Example 1

[0064] In this embodiment, the system of the present invention is used to treat wastewater from a fine chemical industry park. The process is as follows:

[0065] The effluent from the park's regulating pond was tested, and the COD was about 48,000 mg / L, ammonia nitrogen was about 900 mg / L, total nitrogen was about 1,050 mg / L, total phosphorus was about 200 mg / L, and suspended solids ss was about 600 mg / L.

[0066] In this embodiment, two first flotation machines and one second flotation machine are provided in the pretreatment system. Flocculant PAM, coagulant PAC, sodium phosphate and activated carbon powder are added to the water inlet of each flotation machine, and an iron-carbon micro-electrolysis device 1 is provided between the first flotation machine and the second flotation machine.

[0067] The evaporation system is provided with a conventional MVR evaporator 21 and a multiphase flow MVR evaporator 21 connected in series. Scale inhibitors are added to the two evaporators respectively. The scale inhibitor composition is calculated by mass fraction as follows: 20% diethanolamine, 5% sodium polyepoxysuccinate, 5% carbonyl disulfide, 10% sodium dodecylbenzenesulfonate, 3% polyacrylamide, 20% polyether modified polysiloxane defoamer, and the balance is water. Ceramic solid particles are added to the multiphase flow MVR evaporator 21. The preparation process of ceramic solid particles is as follows: The method is as follows: carbon slag from a waste salt treatment system is taken, crushed and passed through a 400-mesh sieve, and iron powder and manganese ore powder are also prepared, both of which are passed through a 400-mesh sieve; 5 parts by weight of carbon slag powder, 5 parts of iron powder, 30 parts of manganese ore powder, and 3 parts of commercially available 100-mesh perlite powder are taken, mixed evenly, and 10 parts of a 20wt.% sodium silicate solution are added, and then formed into small balls with a diameter of about 10 mm. After drying, the small balls are fired in a nitrogen atmosphere at a firing temperature of 1100°C for 15 minutes to obtain the ceramic solid particles of the present invention.

[0068] The evaporation mother liquor obtained by the multiphase flow MVR evaporator 21 is desalted by spray drying; the waste salt generated by spray drying and exhaust gas dust removal is treated by a waste salt treatment system. In the waste salt treatment system, the waste salt is subjected to anaerobic pyrolysis, redissolution, decarbonization and MVR salt separation process to obtain industrial salt, thereby achieving comprehensive treatment of the waste salt and decarbonizing to obtain carbon slag; the generated carbon slag is used as the raw material for the iron-carbon composite layer 12 filler and ceramic solid particles; the condensate obtained by the two-stage MVR evaporator 21 is sent to the adsorption separation system.

[0069] A molecular sieve adsorption tower is provided in the adsorption separation system, and 4A molecular sieve is filled in the adsorption tower. The desorption condensate generated after the molecular sieve desorption steam is condensed is mixed with the evaporation mother liquor; the ozone catalytic oxidation process is adopted in the advanced oxidation system, and the biological treatment system includes multi-stage hydrolysis acidification, UASB anaerobic tower, improved CLR tank, secondary sedimentation tank and MBR tank in sequence.

[0070] The waste gas generated by the pretreatment system and the evaporation system goes to the waste gas treatment system I; the waste gas generated by the thermal drying and waste salt treatment system goes to the waste gas treatment system II; the waste gas generated by the advanced oxidation system and the biochemical treatment system goes to the waste gas treatment system III; the waste gas treatment system I is a high-concentration organic waste gas treatment system, which includes water washing, acid washing absorption, alkali washing absorption, water washing, heterogeneous catalytic oxidation, water washing, electrocatalytic oxidation, and then high-altitude discharge; the waste gas treatment system II is a high-temperature waste gas treatment system, which includes cyclone dust removal, primary water washing, secondary water washing, acid washing absorption, alkali washing absorption, water washing, heterogeneous catalytic oxidation, water washing , electrocatalytic oxidation, and then high-altitude emission; the waste gas treatment system III is a low-concentration organic waste gas treatment system, which includes acid washing absorption, alkaline washing absorption, water washing and biological filter in sequence, and then high-altitude emission; the biological filter is provided with a filler, and the filler includes a plastic shell 3 and ceramic solid particles filled in the plastic shell 3; the wastewater generated in the water washing step is all sent to the front end of the biochemical treatment system, the wastewater generated in the acid washing absorption and alkaline washing absorption steps is all sent to the regulating tank in the pretreatment system, the wastewater generated in the multiphase catalytic oxidation step is all sent to the front end of the advanced oxidation system, and the wastewater generated in the electrocatalytic oxidation step is all sent to the front end of the biochemical treatment system.

[0071] During the operation of the system in this embodiment, the effluents of the pretreatment system, evaporation system, adsorption separation system, advanced oxidation system, and biological treatment system were sampled and tested, and the data are as follows:

[0072] Table 1 Statistics of water inlet and outlet detection data of each section of the system

[0073]

[0074] In addition, the exhaust gas of each waste gas treatment system is tested and can fully meet the emission requirements of the park. It can be seen that the treatment system of the present invention can fully realize the treatment of high-salt, high-organic and highly toxic wastewater in the fine chemical park, while realizing the resource utilization of waste salt, etc., and can achieve standard emission of exhaust gas. The system operation is more energy-saving, complete and stable, and is easy to apply and promote.

[0075] The present invention is not limited to the above-mentioned optimal implementation mode. Anyone can derive other forms of products under the inspiration of the present invention. However, no matter what changes are made in the shape or structure, any technical solution that is the same or similar to that of the present application falls within the scope of protection of the present invention.

Claims

1. A collaborative treatment system for refractory organic wastewater in industrial parks, characterized by: Including pretreatment system, evaporation system, adsorption separation system, advanced oxidation system, biochemical treatment system, waste salt treatment system and waste gas treatment system; The pretreatment system includes a regulating tank. The effluent from the regulating tank is fed through an air flotation and iron-carbon micro-electrolysis device and then to an evaporation system. During the air flotation stage, in addition to adding flocculants and coagulants, soluble phosphates and activated carbon powder are also added to the air flotation machine. An iron-carbon composite layer is provided in the iron-carbon micro-electrolysis device. The evaporation system is a two-stage multiphase flow MVR negative pressure evaporation system, comprising two MVR evaporators connected in series, the first stage being a conventional MVR evaporator and the second stage being a multiphase flow MVR evaporator; the multiphase flow MVR evaporator is filled with ceramic solid particles; the evaporated mother liquor obtained by the multiphase flow MVR evaporator is desalinated by thermal drying; the waste salt produced by desalination is treated by a waste salt treatment system, and the resulting carbon slag is used as filler for the iron-carbon composite layer and raw material for the ceramic solid particles; the condensate obtained by the two-stage MVR evaporators is sent to an adsorption separation system; The effluent from the adsorption separation system is sent to the advanced oxidation system, and the adsorption separation system and the advanced oxidation system further remove COD and toxic substances in the condensate. The effluent from the advanced oxidation system is sent to the biochemical treatment system, and is discharged or reused after being treated by the biochemical treatment system. The waste gas treatment system treats the waste gas generated during the treatment process and then discharges it.

2. The collaborative treatment system for refractory organic wastewater in industrial parks according to claim 1, characterized in that: The regulating tank is provided with multiple, and the effluent of the regulating tank is sequentially passed through the first flotation machine, the iron-carbon micro-electrolysis device, and the second flotation machine before being sent to the evaporation system; the first flotation machine and the second flotation machine are each provided with at least one; the soluble phosphate includes sodium phosphate, which is metered and added according to the concentration of scale-forming ions in the flotation machine inlet water, and the addition amount is 1.2 to 1.5 times the theoretical addition amount; the particle size of the activated carbon micropowder is 50 to 100 μm, and the addition amount is 10 to 50 g / m 3 Water is entering the flotation machine.

3. The collaborative treatment system for refractory organic wastewater in industrial parks according to claim 2, characterized in that: The iron-carbon micro-electrolysis device is provided with multiple layers of fillers, which are, from top to bottom, a filter material layer, an iron-carbon composite layer, and a gravel layer; the filter material layer includes an activated carbon layer; the iron-carbon composite layer is a composite layer of iron and carbon, wherein the mass ratio of iron to carbon is 1:1, the iron is iron filings, 1 to 3 cm long, 0.5 to 1 cm wide, and 0.1 to 0.5 cm thick; and the carbon is carbon slag.

4. The collaborative treatment system for refractory organic wastewater in industrial parks according to claim 1, characterized in that: The two-stage MVR evaporator is added with antiscalant; based on the water flow rate of the MVR evaporator, the amount of antiscalant added is 10-50g / m 3 The ingredients of the scale inhibitor are calculated by weight percentage, including 10-30% diethanolamine, 1-5% sodium polyepoxysuccinate, 5-10% carbonyl disulfide, 10-20% sodium dodecylbenzenesulfonate, 1-5% polyacrylamide, 10-20% polyether modified polysiloxane defoamer, and the balance is water; ceramic solid particles are added to the second stage multiphase flow MVR evaporator. The ceramic solid particles are mixed with carbon slag powder, iron powder, manganese ore powder, pore-forming agent and binder, granulated and dried, sintered under inert gas protection, and cooled. The method is prepared by mixing carbon slag powder, iron powder, manganese ore powder, pore-forming agent and binder in a mass ratio of carbon slag powder: iron powder: manganese ore powder: pore-forming agent: binder = 5-10:5-10:10-30:1-3:5-15; the carbon slag powder, iron powder and manganese ore powder are all sieved through a 200-400 mesh sieve; the granulated particle size is 3-10 mm; the pore-forming agent includes perlite powder; the binder includes 20 wt.% sodium silicate solution; the sintering temperature is 1000-1200° C., and the sintering time is 10-30 min.

5. The collaborative treatment system for refractory organic wastewater in industrial parks according to claim 1, characterized in that: The desalination is achieved by spray drying, and the waste gas generated by spray drying is sent to the waste gas treatment system. Waste salt is obtained during the treatment process of spray drying and the waste gas generated by spray drying. The waste salt is treated by the waste salt treatment system. In the waste salt treatment system, the waste salt is subjected to anaerobic pyrolysis, redissolution, decarbonization and MVR salt separation process to obtain industrial salt, thereby achieving comprehensive treatment of waste salt and decarbonization to obtain carbon slag.

6. The collaborative treatment system for refractory organic wastewater in industrial parks according to claim 1, characterized in that: The adsorption separation system is a molecular sieve adsorption tower filled with 4A molecular sieve filler. After the adsorption separation system is saturated with adsorption, high-temperature steam is used for desorption. The desorption steam is condensed to obtain a desorption condensate, which is mixed with the evaporated mother liquor. The advanced oxidation system is an ozone catalytic oxidation system. The biochemical treatment system includes a multi-stage hydrolysis acidification, a UASB anaerobic tower, a modified CLR tank, a secondary sedimentation tank and an MBR tank connected in sequence.

7. The collaborative treatment system for refractory organic wastewater in industrial parks according to any one of claims 1 to 6, characterized in that: The waste gas generated by the pretreatment system and the evaporation system goes to the waste gas treatment system I; the waste gas generated by the thermal drying and waste salt treatment system goes to the waste gas treatment system II; the waste gas generated by the advanced oxidation system and the biochemical treatment system goes to the waste gas treatment system III.

8. The collaborative treatment system for refractory organic wastewater in industrial parks according to claim 7, characterized in that: The waste gas treatment system I is a high-concentration organic waste gas treatment system, which includes water washing, acid washing absorption, alkaline washing absorption, water washing, multi-phase catalytic oxidation, water washing, electrocatalytic oxidation, and then high-altitude discharge; the waste gas treatment system II is a high-temperature waste gas treatment system, which includes cyclone dust removal, primary water washing, secondary water washing, acid washing absorption, alkaline washing absorption, water washing, multi-phase catalytic oxidation, water washing, electrocatalytic oxidation, and then high-altitude discharge; the waste gas treatment system III is a low-concentration organic waste gas treatment system, which includes acid washing absorption, alkaline washing absorption, water washing and biological filter, and then high-altitude discharge.

9. The collaborative treatment system for refractory organic wastewater in industrial parks according to claim 8, characterized in that: The biological filter is provided with fillers, which include a plastic shell and ceramic solid particles filled in the plastic shell.

10. The collaborative treatment system for refractory organic wastewater in industrial parks according to claim 8, characterized in that: The wastewater generated in the water washing step is all sent to the front end of the biochemical treatment system, the wastewater generated in the acid washing absorption and alkaline washing absorption steps is all sent to the regulating tank in the pretreatment system, the wastewater generated in the heterogeneous catalytic oxidation step is all sent to the front end of the advanced oxidation system, and the wastewater generated in the electrocatalytic oxidation step is all sent to the front end of the biochemical treatment system.

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