Method for treating waste water from the production of sucralose

Abstract

The application discloses a treatment method of trichloro-sucrose production wastewater, and solves the technical problem of trichloro-sucrose production wastewater being difficult to treat in the prior art. The treatment method comprises the following steps: (1) adjusting the pH of the wastewater to 7.5-8.5 to obtain a first liquid; (2) adding a coagulant to the first liquid, and obtaining supernatant through natural sedimentation; (3) performing electrodialysis treatment on the supernatant to obtain concentrated water and dilute water; (4) adding alkali liquor to the dilute water to perform an alkaline hydrolysis reaction, and obtaining dimethylamine and a second liquid after separating and treating the product of the alkaline hydrolysis reaction; (5) adjusting the pH of the second liquid to 6.5-7.5 to obtain a third liquid; (6) performing an electro-catalysis reaction treatment on the third liquid to obtain a fourth liquid; (7) adding anaerobic bacteria and / or facultative bacteria to the fourth liquid to perform a hydrolysis reaction, and obtaining a fifth liquid; and (8) making the fifth liquid and active sludge successively undergo an anaerobic reaction, an anoxic reaction and an aerobic reaction to obtain produced water.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of trichlorosucrose production wastewater treatment, in particular to a trichlorosucrose production wastewater treatment method. BACKGROUND

[0002] Sweeteners refer to food additives that impart sweetness to food. According to their sources, they can be divided into natural additives and artificially synthesized additives. There are many types of natural additives, and currently, natural additives are most commonly extracted from sucrose. With the development of society, natural additives have been unable to meet people's needs, and artificially synthesized additives have emerged as the times require. The most commonly used artificially synthesized food sweetener is trichlorosucrose. Trichlorosucrose is a colorless, odorless white solid with a sweetness of 600 times that of sucrose, and its physicochemical properties are stable and not easily decomposed.

[0003] There are many trichlorosucrose production processes, but the main raw materials are basically the same. One commonly used trichlorosucrose production process is to mix raw ethyl ester trimethyl ester and sucrose in a certain proportion to form a cyclic compound using DMF as a solvent, then open the ring of the cyclic compound under the action of water, and then make the acetyl group migrate through an organic base to obtain part of sucrose-6-acetate. After chlorination and deacetylation, trichlorosucrose is obtained. In the process of synthesizing trichlorosucrose, the yield conversion is low, part of the raw materials is easily combined into other by-products, and some organic solvents are not well recovered. Therefore, the trichlorosucrose production wastewater comes from the synthesis product of each stage, and the wastewater production is high.

[0004] Trichlorosucrose production wastewater is a high-concentration organic chemical wastewater. The wastewater has the characteristics of high COD, high ammonia nitrogen, high salt content, and poor biodegradability. The difficult-to-degrade substances in the wastewater, such as DMF (N, N-dimethylformamide), chloroform, and chlorinated by-products (monochlorosucrose, dichlorosucrose, and tetrachlorosucrose) produced during the production of trichlorosucrose, have an inhibitory effect on microorganisms. At the same time, their structures are stable, and it is difficult for general physical and chemical methods to cause damage to them. Therefore, if trichlorosucrose production wastewater is not well treated, it will affect the development of the industry to some extent.

[0005] Currently, there are two ways to treat trichlorosucrose production wastewater. One is through single-stage concentration to obtain a low-boiling solid containing a large amount of inorganic salts and organic matter, and the low-boiling solid is finally treated by incineration. However, the solid low-boiling solid has a low heat value and needs to be supplemented with a combustion aid, and a large amount of toxic and harmful gases are generated during the incineration process, which need to be treated. The other way is wet catalytic oxidation + membrane separation + MVR. However, due to the high content of organic matter and suspended solids in the wastewater, the equipment pipes are prone to blockage, frequent cleaning is required, and the equipment is severely corroded due to the high chlorine ion content in the wastewater. At the same time, the evaporated ammonium chloride still contains a large amount of organic matter, and the impurities are too many to be reused. SUMMARY

[0006] The main purpose of the present application is to provide a trichlorosucrose production wastewater treatment method and treatment system to solve the technical problem of trichlorosucrose production wastewater difficult to handle in the prior art.

[0007] In order to achieve the above-mentioned purpose, the present application first provides a trichlorosucrose production wastewater treatment method, and the technical scheme is as follows:

[0008] The trichlorosucrose production wastewater treatment method comprises the following steps: (1) adjusting the pH of the wastewater to 7.5-8.5 to obtain a first liquid; (2) adding a coagulant to the first liquid, and obtaining a supernatant by natural sedimentation; (3) performing electrodialysis treatment on the supernatant to obtain concentrated water and dilute water; (4) adding an alkali solution to the dilute water to perform an alkaline hydrolysis reaction, and obtaining dimethylamine and a second liquid after separating and treating the product of the alkaline hydrolysis reaction; (5) adjusting the pH of the second liquid to 6.5-7.5 to obtain a third liquid; (6) performing an electrocatalytic reaction treatment on the third liquid to obtain a fourth liquid; (7) adding anaerobic bacteria and / or facultative bacteria to the fourth liquid to perform a hydrolysis reaction, and obtaining a fifth liquid; and (8) sequentially performing an anaerobic reaction, an anoxic reaction and an aerobic reaction on the fifth liquid and activated sludge to obtain product water.

[0009] As a further improvement of the treatment method of the present application, the pH of the production wastewater is ≤6.8, the COD concentration is ≥80000 mg / L, the ammonia nitrogen concentration is ≥12000 mg / L, and the conductivity is ≥100000 us / cm.

[0010] As a further improvement of the treatment method of the present application, the coagulant is any one of polymeric ferric sulfate, polymeric aluminum sulfate and polyacrylamide.

[0011] As a further improvement of the treatment method of the present application, the duration of the electrodialysis treatment is 4-8 h, the current is 0.5-3.0 A, and the voltage is 5-40 V.

[0012] As a further improvement of the treatment method of the present application, the alkali solution is sodium hydroxide, the duration of the alkaline hydrolysis reaction is 2-4 h, and the operating temperature is 98-100℃.

[0013] As a further improvement of the treatment method of the present application, the duration of the electrocatalytic reaction is 3-6 h, and the electrode material is a titanium alloy plating layer.

[0014] As a further improvement of the treatment method of the present application, the duration of the hydrolysis reaction is 10-14 h.

[0015] As a further improvement of the treatment method of the present application, the fifth liquid is first subjected to an anaerobic reaction with activated sludge, and after three-phase separation, a sixth liquid is obtained; then the sixth liquid is subjected to an anoxic reaction and an aerobic reaction with activated sludge in sequence, and after three-phase separation, product water is obtained.

[0016] As a further improvement of the treatment method of the present application, the duration of the anaerobic reaction is 3-5 days; the duration of the anoxic reaction and the aerobic reaction is 2.5-4 days.

[0017] As a further improvement of the treatment method of the present application, it further comprises subjecting the concentrated water to evaporation crystallization treatment to obtain ammonium salt.

[0018] In order to achieve the above-mentioned purpose, the present application further provides a treatment system for trichlorosucrose production wastewater, and the technical scheme is as follows:

[0019] The treatment system for trichlorosucrose production wastewater comprises: a first adjusting tank for adjusting the pH of the wastewater and outputting a first liquid; a first reaction tank for reacting the first liquid with a coagulant to generate a solid-liquid mixture and outputting supernatant; an electrodialysis device for performing electrodialysis treatment on the supernatant and outputting concentrated water and dilute water; an alkaline hydrolysis unit for performing alkaline hydrolysis reaction on the dilute water and alkali liquor and separating the product of the alkaline hydrolysis reaction and outputting dimethylamine and a second liquid; a second adjusting tank for adjusting the pH of the second liquid and outputting a third liquid; an electro-catalytic device for performing electro-catalytic reaction treatment on the third liquid and outputting a fourth liquid; a second reaction tank for performing hydrolysis reaction on the fourth liquid and anaerobic bacteria and / or facultative bacteria and outputting a fifth liquid; and an activated sludge reaction unit for sequentially subjecting the fifth liquid to anaerobic reaction, anoxic reaction and aerobic reaction with activated sludge and outputting product water.

[0020] As a further improvement of the treatment system of the present application, it further comprises a water collecting well for storing the wastewater and a lifting pump for inputting the wastewater in the water collecting well into the first adjusting tank.

[0021] As a further improvement of the treatment system of the present application, it further comprises a first feeding device for adding an alkaline adjusting agent, a second feeding device for adding a coagulant, a third feeding device for adding an acidic adjusting agent, and a fourth feeding device for adding anaerobic bacteria and / or facultative bacteria.

[0022] As a further improvement of the treatment system of the present application, it further comprises a filtering device, and the supernatant is filtered by the filtering device before entering the electrodialysis device.

[0023] As a further improvement of the treatment system of the present application, it further comprises an evaporation crystallization device for performing evaporation crystallization treatment on the concentrated water.

[0024] As a further improvement of the treatment system of the present application, the alkali dissolution unit comprises: a third reaction tank for carrying out alkali dissolution reaction of the fresh water and the alkali solution; a separation device for separating the product of the alkali dissolution reaction and outputting dimethylamine and a second liquid; and a fifth feeding device for feeding the alkali solution into the third reaction tank.

[0025] As a further improvement of the treatment system of the present application, the separation device is a rectification device.

[0026] As a further improvement of the treatment system of the present application, the activated sludge reaction unit comprises:

[0027] an IC reactor for carrying out anaerobic reaction of the fifth liquid with the activated sludge and outputting a sixth liquid;

[0028] an AO reaction system for carrying out anoxic reaction and aerobic reaction of the sixth liquid with the activated sludge and outputting product water.

[0029] As a further improvement of the treatment system of the present application, the AO reaction system comprises at least two groups of anoxic reaction tanks and aerobic reaction tanks.

[0030] As a further improvement of the treatment system of the present application, it further comprises a settling tank for storing and settling the flocculent precipitate output by the first reaction tank and the sludge output by the activated sludge reaction unit.

[0031] In the treatment method and treatment system of the trichloro sucrose production wastewater of the present application, firstly, higher-purity ammonium salt (mainly ammonium chloride) and dimethylamine can be obtained, which is convenient for secondary utilization and significantly improves the economic value. Secondly, most of the salt and conductive substances in the wastewater are transferred to the concentrated water side by the electrodialysis device, so that the conductivity and salt content of the fresh water are greatly reduced, the biodegradability is significantly improved, and the biochemical treatment can be directly carried out, thereby ensuring the efficient removal of COD and ammonia nitrogen, and the product water can be discharged up to the standard, which is green and environmentally friendly. Moreover, by organically combining a plurality of water treatment devices in a specific sequence, the energy consumption is significantly reduced, thereby reducing the equipment investment cost and operation cost. It can be seen that the treatment method of the present application has simple process, and conventional equipment can be used to realize economic, efficient and deep treatment of trichloro sucrose production wastewater, effectively solving the technical problem of difficult treatment of phosphoric acid production wastewater in the prior art, and having strong practicability.

[0032] The present application is further described below in conjunction with the accompanying drawings and specific embodiments. Additional aspects and advantages of the present application will be partially given in the following description, partially will become apparent from the following description, or will be understood by those skilled in the art through practice of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0033] The accompanying drawings, which form a part of this application, are included to provide a further understanding of the application and are incorporated in and constitute a part of this application. The drawings provided in the accompanying drawings and the related descriptions in the present application can be used to explain the present application, but do not constitute an improper limitation on the present application. In the drawings:

[0034] Figure 1 A structural schematic diagram of one embodiment of the treatment system for the trichlorosucrose production wastewater of the present application.

[0035] The relevant signs in the above drawings are as follows:

[0036] 100 - a water collecting well, 110 - a first adjusting tank, 210 - a first reaction tank, 310 - a filtering device, 300 - an electrodialysis device, 320 - an evaporation crystallization device, 230 - a third reaction tank, 400 - a rectification device, 120 - a second adjusting tank, 500 - an electrocatalysis device, 220 - a second reaction tank, 610 - an IC reactor, 620 - an AO reaction system, 710 - a first feeding device, 720 - a second feeding device, 730 - a third feeding device, 740 - a fourth feeding device, 750 - a fifth feeding device, 800 - a sedimentation tank. DETAILED DESCRIPTION

[0037] The present application will be described in detail below with reference to the drawings. Those skilled in the art will be able to implement the present application based on these descriptions. Before the present application is described in detail with reference to the drawings, it is particularly pointed out that:

[0038] The technical solutions and technical features provided in each part of the present application, including the following descriptions, can be combined with each other without conflict.

[0039] In addition, the embodiments of the present application involved in the following descriptions are generally only a part of the embodiments of the present application, but not all the embodiments. Therefore, all other embodiments obtained by those skilled in the art based on the embodiments in the present application without creative labor should belong to the scope of protection of the present application.

[0040] Regarding the terms and units in the present application. The terms "include", "have" and any variations thereof in the specification and claims of the present application and related parts are intended to cover non-exclusive inclusion.

[0041] Figure 1 A structural schematic diagram of one embodiment of the treatment system for the trichlorosucrose production wastewater of the present application.

[0042] As Figure 1As shown, the treatment system of sucralose production wastewater includes a water collecting well 100, a first adjusting tank 110, a first reaction tank 210, a filtration device 310, an electrodialysis device 300, an evaporation crystallization device 320, an alkaline hydrolysis unit, a second adjusting tank 120, an electro-catalytic device 500, a second reaction tank 220, an activated sludge reaction unit, a first feeding device 710, a second feeding device 720, a third feeding device 730, a fifth feeding device 750, and a sedimentation tank 800.

[0043] The water collecting well 100 is used for storing wastewater, and the wastewater in the water collecting well 100 is input into the first adjusting tank 110 through a lifting pump.

[0044] The first adjusting tank 110 is used for adjusting the pH of the wastewater, and outputs a first liquid; the first feeding device 710 is used for inputting an alkaline adjusting agent into the first adjusting tank 110.

[0045] The first reaction tank 210 is used for reacting the first liquid with a coagulant to generate a solid-liquid mixture, and outputs a supernatant; the second feeding device 720 is used for inputting a coagulant into the first reaction tank 210. The coagulant refers to a substance that can play a flocculation and coagulation role in the aggregation process of colloidal particles and small suspended matters in water.

[0046] The electrodialysis device 300 is used for performing electrodialysis treatment on the supernatant, and outputs concentrated water and dilute water; preferably, the supernatant is filtered through the filtration device 310 before entering the electrodialysis device 300, so as to improve the electrodialysis separation effect, reduce the energy consumption of the electrodialysis device 300, and prolong the service life.

[0047] The evaporation crystallization device 320 is used for performing evaporation crystallization treatment on the concentrated water; the evaporation crystallization device 320 is preferably an MVR evaporator.

[0048] The alkaline hydrolysis unit is used for performing an alkaline hydrolysis reaction between DMF in the dilute water and an alkali liquor to generate formate and dimethylamine, and then performing separation treatment on the products of the alkaline hydrolysis reaction, so as to obtain dimethylamine and a second liquid.

[0049] The alkaline hydrolysis unit includes a third reaction tank 230, a separation device, and a fifth feeding device 750; the third reaction tank 230 is used for performing an alkaline hydrolysis reaction between the dilute water and the alkali liquor; the separation device is used for performing separation treatment on the products of the alkaline hydrolysis reaction, and outputs dimethylamine and the second liquid; the separation device is preferably a rectification device 400; and the fifth feeding device 750 is used for adding the alkali liquor into the third reaction tank 230.

[0050] The second adjusting tank 120 is used for adjusting the pH of the second liquid, and outputs a third liquid; the third feeding device 730 is used for inputting an acidic adjusting agent into the second adjusting tank 120.

[0051] The electro-catalytic device 500 is used for electro-catalytic reaction treatment of the third liquid, and outputs a fourth liquid; the electro-catalytic device 500 is preferably a multi-dimensional electro-catalytic oxidation device, under the condition of power supply, the electrodes and the catalytic materials on the surfaces of the electrodes generate active groups such as hydroxyl radicals and superoxide radicals which can react with organic matters in wastewater, so as to degrade part of the refractory macromolecular organic matters or cyclic organic matters into small organic molecules which can be biodegraded, and improve the B / C (i.e. the ratio of BOD to COD, BOD refers to biochemical oxygen demand, and COD refers to chemical oxygen demand) of the wastewater.

[0052] The second reaction tank 220 is used for hydrolysis reaction of the fourth liquid and anaerobic bacteria and / or facultative bacteria (bacteria which can grow and metabolize under aerobic and anaerobic conditions) and outputs a fifth liquid; after the electro-catalytic device 500, the anaerobic bacteria and / or facultative bacteria in the second reaction tank 220 can hydrolyze the residual refractory macromolecular substances in the wastewater into small molecular substances which can be biodegraded, and further improve the B / C of the wastewater. The fourth feeding device 740 is used for inputting the anaerobic bacteria and / or facultative bacteria into the second reaction tank 220.

[0053] The activated sludge reaction unit is used for anaerobic reaction, anoxic reaction and aerobic reaction of the fifth liquid and activated sludge in sequence, and outputs product water. The activated sludge reaction unit is a biochemical reaction unit, and is preferably an IC reactor 610 and an AO reaction system 620; the IC reactor 610 is used for anaerobic reaction of the fifth liquid and activated sludge, and outputs a sixth liquid; the AO reaction system 620 is used for anoxic reaction and aerobic reaction of the sixth liquid and activated sludge, and outputs product water.

[0054] The IC (internal circulation) reactor 610 is an internal circulation anaerobic reactor which is composed of two reaction chambers, the fifth liquid flows from bottom to top in the IC reactor 610, pollutants are adsorbed and degraded by bacteria, and the purified water flows out from the upper part of the IC reactor 610.

[0055] The AO reaction system 620 includes an anoxic reaction tank and an aerobic reaction tank; in the anoxic reaction tank, the polyphosphorus bacteria utilize a small amount of carbon source to release the phosphorus in the body and use nitrate as an electron acceptor for anaerobic respiration, and the energy generated is used for phosphorus absorption, and the nitrate in the sludge return liquid is reduced and denitrified by denitrifying bacteria, and the anoxic environment is mixed and maintained by a stirrer. In the aerobic reaction tank, phosphorus is absorbed, organic nitrogen is ammoniated, nitrification is performed, and BOD and COD are degraded. Preferably, the anoxic reaction tank and the aerobic reaction tank are at least two groups and are arranged alternately, the sixth liquid is segmented into water, the mixed liquid output from the upper segment after sufficient reaction enters the anoxic reaction tank of the lower segment together with the water of the lower segment.

[0056] Since the fifth liquid has high COD, high ammonia nitrogen and high total nitrogen, it is difficult to make the COD of the produced water meet the discharge standard by using single A2O, and high concentration COD will also affect the degradation of ammonia nitrogen and total nitrogen by nitrifying bacteria and denitrifying bacteria, but the treatment system of the present application can reduce the COD of the fifth liquid through the IC reactor 610, and then ensure that the COD, ammonia nitrogen and total nitrogen of the produced water can meet the discharge standard through the multi-stage AO reaction system 620.

[0057] The sedimentation tank 800 is used to store and settle the flocculent precipitate output by the first reaction tank 210 and the sludge output by the activated sludge reaction unit. The settled sludge in the sedimentation tank 800 is subsequently dewatered by a special mechanism.

[0058] The embodiment of the method for treating trichlorosucrose production wastewater of the present application specifically comprises the following steps by using the above treatment system:

[0059] (1) Adjust the pH of the wastewater to 7.5-8.5 to obtain the first liquid; by adjusting the pH of the wastewater, the coagulation effect can be improved and the amount of reagent can be reduced.

[0060] (2) Add a coagulant to the first liquid, and obtain supernatant by natural sedimentation; the coagulant is any of polyferric sulfate (PFS), polyaluminum chloride (PAC) and polyacrylamide (PAM). In this way, the suspended solids in the first liquid can be significantly reduced to prevent the suspended solids from affecting the subsequent sections.

[0061] (3) Perform electrodialysis treatment on the supernatant to obtain concentrated water and dilute water; the duration of the electrodialysis treatment is 4-8 h, the current is 0.5-3.0 A, and the voltage is 5-40 V.

[0062] (4) Perform evaporation crystallization treatment on the concentrated water to obtain ammonium salt.

[0063] (5) Add an alkali solution to the dilute water to perform alkaline hydrolysis reaction, and separate the product of the alkaline hydrolysis reaction to obtain dimethylamine and the second liquid; the alkali solution is sodium hydroxide, the duration of the alkaline hydrolysis reaction is 2-4 h, and the operating temperature is 98-100℃.

[0064] (6) Adjust the pH of the second liquid to 6.5-7.5 to obtain the third liquid; by adjusting the pH of the second liquid, the electrocatalytic treatment effect can be improved.

[0065] (7) Perform electrocatalytic reaction treatment on the third liquid to obtain the fourth liquid; the duration of the electrocatalytic reaction is 3-6 h, and the electrode material is titanium alloy plating.

[0066] (8) Add anaerobic bacteria and / or facultative bacteria to the fourth liquid to perform hydrolysis reaction to obtain the fifth liquid; the duration of the hydrolysis reaction is 10-14 h.

[0067] (9) The fifth liquid is subjected to an anaerobic reaction with activated sludge, and after three-phase separation, a sixth liquid is obtained; the anaerobic reaction lasts for 3-5 days.

[0068] (10) The sixth liquid is subjected to an anoxic reaction and an aerobic reaction with activated sludge in sequence, and after three-phase separation, product water is obtained; the anoxic reaction and the aerobic reaction last for 2.5-4 days.

[0069] It has been verified that the treatment method and treatment system for trichlorosucrose production wastewater can effectively treat trichlorosucrose production wastewater with pH ≤ 6.8, COD concentration ≥ 80000 mg / L, ammonia nitrogen (NH3-N, referring to nitrogen existing in the form of free ammonia (NH3) and ammonium ion (NH4 + ) in water) concentration ≥ 12000 mg / L, and electrical conductivity ≥ 100000 us / cm. The beneficial effects of the treatment method and treatment system for trichlorosucrose production wastewater of the present application will be illustrated by specific examples below.

[0070] The trichlorosucrose production wastewater of the present example has a pH of 6.18, a COD concentration of 103250 mg / L, an ammonia nitrogen concentration of 17560 mg / L, an electrical conductivity of 112100 us / cm, and a yield of 60 m 3 / d.

[0071] (1) In the first adjusting tank 110, the pH is adjusted by 25% ammonia water (i.e. alkaline adjusting agent) to obtain a first liquid with a pH of 8.5.

[0072] (2) The first liquid in the first adjusting tank 110 is pumped into the first reaction tank 210 by a submersible pump, and 35% polymeric ferric sulfate (i.e. coagulant) is added, with a volume ratio of polymeric ferric sulfate to first liquid of 1:100, stirring for 30 min, and standing for 3 h for precipitation, to obtain supernatant with a COD of 91250 mg / L and an ammonia nitrogen of 18760 mg / L. The supernatant enters the electrodialysis equipment 300, and the flocculent precipitate at the bottom enters the sedimentation tank.

[0073] (3) The pollutants in the supernatant are separated by the electrodialysis equipment 300, so that the organic matter, DMF and chlorinated by-products in the supernatant remain in the fresh water chamber, and most of the inorganic salts and part of the COD enter the concentrated water chamber; the COD of the fresh water in the fresh water chamber is 51150 mg / L, which enters the alkaline hydrolysis unit; the COD of the concentrated water in the concentrated water chamber is 32150 mg / L, which enters the evaporation crystallization equipment 320. Subsequently, the concentrated water is evaporated and concentrated by the evaporation crystallization equipment 320, and 3.2 tons of ammonium salt can be obtained.

[0074] (4) The fresh water first enters the third reaction tank 230 of the alkaline hydrolysis unit, and sodium hydroxide (i.e. lye) is added to make the pH of the fresh water ≥ 14, and then the alkaline hydrolysis reaction is carried out at 98-100°C for 3h to generate a mixture containing sodium formate and dimethylamine; the mixture enters the rectification equipment 400 for separation treatment, and 1.5 tons of dimethylamine (mass fraction 35%) is recovered, and the COD of the obtained second liquid is 47150mg / L.

[0075] (5) In the second adjusting tank 120, the second liquid is adjusted to the third liquid with pH 7 by using hydrochloric acid.

[0076] (6) The third liquid flows into the multi-dimensional electro-catalytic oxidation equipment, and the active groups such as hydroxyl radicals and superoxide radicals generated by the titanium alloy plating layer catalytic material on the surface of the electrode degrade part of the macromolecular organic matters in the third liquid, and the COD of the fourth liquid after the electro-catalytic reaction for 4h is 41150mg / L, and the ammonia nitrogen is 660mg / L.

[0077] (7) The fourth liquid stays in the second reaction tank 220 for 12h, during which the anaerobic bacteria and facultative bacteria continue to degrade the refractory macromolecular organic matters to generate the fifth liquid.

[0078] (8) The fifth liquid enters the IC reactor 610 through the submersible pump and stays for 4 days, during which the anaerobic bacteria degrade the COD into CO2 and methane, so that the COD is greatly reduced, and the COD of the generated sixth liquid is 2150mg / L, and the ammonia nitrogen is 1320mg / L.

[0079] (9) The sixth liquid flows into the AO reaction system 620 and stays for 3.5 days, and the ammonia nitrogen, nitrate nitrogen and COD in the sixth liquid are converted into CO2, H2O, N2 and other substances under the action of nitrifying bacteria and denitrifying bacteria, and the COD of the obtained product water is 325mg / L, and the ammonia nitrogen is 18mg / L.

[0080] Ammonia nitrogen: refers to the nitrogen in the form of free ammonia (NH3) and ammonium ion (NH4 + ) in water.

[0081] Nitrate nitrogen: refers to all nitrogen elements in nitrate.

[0082] Total nitrogen: the total amount of various forms of inorganic and organic nitrogen in water, i.e. all forms of nitrogen in water, including ammonia nitrogen and nitrate nitrogen.

[0083] The above describes the relevant content of the present application. Those skilled in the art can implement the present application based on the above description. Based on the above content of the present application, all other embodiments obtained by those skilled in the art without creative labor should belong to the protection scope of the present application.

Claims

1. A method for treating wastewater from sucralose production, characterized in that: Includes the following steps: (1) Adjust the pH of the wastewater to 7.5-8.5 to obtain the first liquid; (2) Add coagulant to the first liquid and obtain the supernatant by natural sedimentation; (3) The supernatant was subjected to electrodialysis to obtain concentrated water and desalinated water; (4) The concentrated water is evaporated and crystallized to obtain ammonium salt; an alkaline solution is added to the fresh water to carry out an alkaline hydrolysis reaction, and the products of the alkaline hydrolysis reaction are separated to obtain dimethylamine and a second liquid; (5) Adjust the pH of the second liquid to 6.5-7.5 to obtain the third liquid; (6) The third liquid is subjected to an electrocatalytic reaction to obtain the fourth liquid; (7) Add anaerobic bacteria and / or facultative bacteria to the fourth liquid to carry out a hydrolysis reaction to obtain the fifth liquid; (8) The fifth liquid and the activated sludge undergo anaerobic, anoxic and aerobic reactions in sequence to obtain permeable water.

2. The method for treating sucralose production wastewater as described in claim 1, characterized in that: The production wastewater has a pH ≤ 6.8, COD concentration ≥ 80000 mg / L, ammonia nitrogen concentration ≥ 12000 mg / L, and conductivity ≥ 100000 μS / cm.

3. The method for treating sucralose production wastewater as described in claim 1, characterized in that: The coagulant is any of the following: polyferric sulfate, polyaluminum sulfate, and polyacrylamide.

4. The method for treating sucralose production wastewater as described in claim 1, characterized in that: The electrodialysis treatment lasts for 4 to 8 hours, with a current of 0.5 to 3.0 A and a voltage of 5 to 40 V.

5. The method for treating sucralose production wastewater as described in claim 1, characterized in that: The alkaline solution is sodium hydroxide, the alkaline hydrolysis reaction lasts for 2 to 4 hours, and the operating temperature is 98°C to 100°C.

6. The method for treating sucralose production wastewater as described in claim 1, characterized in that: The electrocatalytic reaction lasts for 3 to 6 hours, and the electrode material is a titanium alloy coating.

7. The method for treating sucralose production wastewater as described in claim 1, characterized in that: The hydrolysis reaction lasts for 10 to 14 hours.

8. The method for treating sucralose production wastewater as described in claim 1, characterized in that: First, the fifth liquid is subjected to an anaerobic reaction with activated sludge, and after three-phase separation, the sixth liquid is obtained. Then, the sixth liquid is subjected to anoxic and aerobic reactions with activated sludge in sequence, and after three-phase separation, the permeate is obtained.

9. The method for treating sucralose production wastewater as described in claim 8, characterized in that: The duration of the anaerobic reaction is 3 to 5 days; the duration of the hypoxic reaction and the aerobic reaction is 2.5 to 4 days.

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