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CN118458978A - Method for treating high-salt organic wastewater - Google Patents

Method for treating high-salt organic wastewater Download PDF

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Publication number
CN118458978A
CN118458978A CN202410481702.XA CN202410481702A CN118458978A CN 118458978 A CN118458978 A CN 118458978A CN 202410481702 A CN202410481702 A CN 202410481702A CN 118458978 A CN118458978 A CN 118458978A
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salt
product
salt organic
treatment
organic wastewater
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伍立波
万金玲
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Hangzhou Shenrui Environment Co ltd
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Hangzhou Shenrui Environment Co ltd
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    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F9/00Multistage treatment of water, waste water or sewage
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00Treatment of water, waste water, or sewage
    • C02F1/28Treatment of water, waste water, or sewage by sorption
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00Treatment of water, waste water, or sewage
    • C02F1/44Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
    • C02F1/442Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by nanofiltration
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00Treatment of water, waste water, or sewage
    • C02F1/66Treatment of water, waste water, or sewage by neutralisation; pH adjustment
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00Treatment of water, waste water, or sewage
    • C02F1/72Treatment of water, waste water, or sewage by oxidation
    • C02F1/725Treatment of water, waste water, or sewage by oxidation by catalytic oxidation
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00Nature of the contaminant
    • C02F2101/10Inorganic compounds

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  • Life Sciences & Earth Sciences (AREA)
  • Hydrology & Water Resources (AREA)
  • Engineering & Computer Science (AREA)
  • Environmental & Geological Engineering (AREA)
  • Water Supply & Treatment (AREA)
  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Treatment Of Water By Oxidation Or Reduction (AREA)
  • Removal Of Specific Substances (AREA)
  • Separation Using Semi-Permeable Membranes (AREA)

Abstract

The invention discloses a method for treating high-salt organic wastewater, which comprises soluble organic matters and at least one of the following salts with the mass percentage concentration of 5-22 percent: the method for treating the high-salt organic wastewater comprises the following steps of: (S1200) a catalytic oxidation step: carrying out subcritical water catalytic oxidation treatment on the high-salt organic matter wastewater to obtain a first product; wherein the subcritical water catalytic oxidation treatment comprises: and (3) regulating the pH value of the high-salt organic matter wastewater to be 2-5, adding a catalyst, and carrying out subcritical water catalytic oxidation under the conditions of the reaction temperature of 200-300 ℃ and the reaction pressure of 5-20 Mpa.

Description

Method for treating high-salt organic wastewater
Technical Field
The invention relates to the technical field of wastewater treatment. More particularly, the present invention relates to a method of treating high-salt organic wastewater.
Background
With the rapid development of the chemical industry, a large amount of high-salt organic wastewater is generated, and the wastewater is increased year by year, so that the treatment difficulty and the treatment cost of the high-salt organic wastewater are increased due to the characteristics of high salt content and difficult degradation. The high-salt organic wastewater produced in the industrial production process has the characteristics of complex components, high salinity, high organic matter concentration, high toxicity and the like, wherein the organic matter concentration exceeds 10000mg/L, the salt content is more than 5 percent, and even the saturated salt concentration is reached. Some wastewater also has a high color and volatilizes malodorous odors. The domestic method for treating the wastewater is mainly a physicochemical method, a biochemical method or a combined process. Physical method for removing salt includes evaporation concentration crystallization method, incineration method, membrane concentration method, etc.; the chemical method mainly comprises advanced oxidation method for removing organic matters, such as Fenton oxidation method, electrocatalytic oxidation method, wet oxidation method, supercritical/pressurized water oxidation method, and photochemical oxidation method.
For the treatment of the high-salt organic wastewater, the evaporation concentration method can extract salt, and the patent CN20210002001138.8 adopts an evaporation crystallization system to treat the high-salt wastewater, so that the high-salt wastewater can be effectively recycled, but for the high-salt wastewater containing organic matters, the evaporation boiling point is increased, the evaporation crystallization difficulty is high, the evaporation concentration mother liquor is difficult to treat, and equipment is blocked. The chemical method can effectively remove the organic matters, and the process combining the chemical oxidation method and the evaporation process can effectively solve the difficulty that the organic matter wastewater is difficult to evaporate. The wastewater can be effectively treated by adopting a supercritical oxidation method, but the defects of easy corrosion, salt deposition and high energy consumption exist in the operation process because of the low solubility in the supercritical state in industrialization.
The incineration method is the most widely used method at present, the CN202021582404.3 can effectively and completely remove organic matters in the wastewater by adopting the incineration method, and pure salt is extracted, but substances such as nitrogen oxides, dioxin and the like are easy to produce by incineration, the tail gas treatment process is complex, and the treatment flow is long. Meanwhile, salt in the wastewater severely corrodes equipment at high temperature.
The evaporation concentration method and the incineration method can extract salt, however, the salt extracted from the wastewater is generally treated by landfill at present, and the cost is high. There is thus an urgent need for a method capable of green-treating high-salt wastewater.
Disclosure of Invention
To this end, the present invention proposes a novel method of treating high-salt organic wastewater that can solve at least a part of the above problems.
According to one aspect of the invention, the high-salt organic wastewater comprises soluble organic matters and at least one of the following salts with the mass percentage concentration of 5% -22%: chlorine salt, sulfate and nitrate,
The method for treating the high-salt organic wastewater comprises the following steps of:
S1200, catalytic oxidation step: carrying out subcritical water catalytic oxidation treatment on the high-salt organic matter wastewater to obtain a first product;
wherein the subcritical water catalytic oxidation treatment comprises: and (3) regulating the pH value of the high-salt organic matter wastewater to be 2-5, adding a catalyst, and carrying out subcritical water catalytic oxidation under the conditions of the reaction temperature of 200-300 ℃ and the reaction pressure of 5-20 Mpa.
The soluble organics include: macromolecular organic substances (oil, fat, surfactant), and solvent organic substances (such as phenol, acetone, tetrahydrofuran, dichloromethane, toluene, etc.).
Preferably, the high salt of the present invention includes chloride (sodium chloride, potassium chloride), sulfate (sodium sulfate, potassium sulfate), nitrate (sodium nitrate, potassium nitrate) or a mixed salt thereof.
Preferably, the high salt treated by the method is chloride salt, sulfate, nitrate or a mixture thereof with the concentration of 5-22% (mass percent), and the cation can be potassium ion and sodium ion. Thus, the brine is sodium chloride brine, potassium sulfate brine or a mixture thereof with the concentration exceeding 5 percent, and can also be sodium chloride brine, sodium sulfate brine or a mixture thereof with the concentration exceeding 5 percent.
Preferably, the catalyst comprises at least one of the following: manganese ions, cobalt ions, cadmium ions, zinc ions, and copper ions; more preferably, the concentration of the catalyst is 50-2000mg/L.
Removing most of organic matters through subcritical water catalytic oxidation to obtain a first product, wherein the organic matters are degraded into CO 2, water and N 2 in the first product; oxidation of lower valence S such as S 2-,SO3 2 -, rxSy to the highest valence S, namely SO 4 2-.
Preferably, in the present invention, subcritical water oxidation is carried out at a pH of 2 to 5, the catalyst efficiency is high, and in this case, the oxidation is carried out, and the catalyst ions in the oxidizing liquid are not precipitated. The catalyst can improve the organic matter removal efficiency to more than 98%, the concentration of the produced water organic matter is low, the pollution of the subsequent bipolar membrane is reduced, and the purity of the produced acid and alkali is improved.
The pressure is used for reducing the gasification rate at high temperature, ensuring the reaction in liquid phase reaction and not precipitating salt. The central influencing factor of the reaction is the temperature. Preferably, the catalyst mainly adopts transition metal ions, the catalyst concentration is 50-12000 mg/L, and according to different organic matters and removal purposes, the temperature and the catalyst concentration are required to be increased simultaneously. Preferably, the catalyst can be manganese, cobalt, cadmium, zinc, copper and other ions, has high catalytic activity, and when the catalyst is selected, the catalyst anion can be selected to be equal to the salt solution to be treated, no new anion is introduced, so that the subsequent acid purity is not influenced.
After subcritical water catalytic oxidation, the effluent is preheated by a heat exchanger, the water is fed to recover heat energy, and then cooled to reduce the temperature to 25-40 ℃ so as to facilitate feeding in the subsequent membrane process.
According to one embodiment of the present invention, in S1200, the catalyst includes at least one of the following: manganese ions, cobalt ions, cadmium ions, zinc ions, and copper ions;
The concentration of the catalyst is 50-2000mg/L.
According to one embodiment of the present invention, before the step S1200, the method further includes a step S1100 of preprocessing: before the subcritical water catalytic oxidation treatment of the high-salt organic matter wastewater, removing one or more of the following ions by a resin adsorption or flocculation precipitation method: calcium ion, magnesium ion, silicate ion, and fluoride ion.
S1100, preprocessing: before the subcritical water catalytic oxidation treatment of the high-salt organic matter wastewater, the method further comprises the step of removing one or more of the following ions through a resin adsorption or flocculation precipitation method: calcium ion, magnesium ion, silicate ion, and fluoride ion.
If the high-salt organic matter wastewater contains calcium, magnesium, silicon, fluorine and other ions, the high-salt organic matter wastewater needs to be removed in advance; the solid particles contained in the wastewater need to be removed in advance. Calcium, magnesium, silicon and fluorine can be removed by resin adsorption; or adding a medicament, and removing by adopting a flocculation precipitation method.
Calcium, magnesium and silicon can cause scaling of subcritical water catalytic oxidation equipment, and fluorine can cause corrosion of subcritical water catalytic oxidation equipment. The granular solid produced by flocculation precipitation can be filtered by methods of filter pressing, automatic back flushing filter, ultrafiltration and the like, and the filtering precision is 0.1-100 microns.
After the pretreatment process is carried out to remove the calcium, magnesium, silicon, fluorine plasma, oil, grease and solvent organic matters, the interference of the matters on the bipolar membrane can be eliminated.
According to an embodiment of the present invention, step S1200 further includes: s1300 catalyst removal step: and (3) adsorbing the first product by using chelating resin to remove the catalyst, so as to obtain a second product.
In the step of removing the catalyst in S1300, preferably, the chelating resin capable of removing ions such as manganese, cobalt, cadmium, zinc, copper and the like is used for adsorbing and removing the catalyst in the first product, so as to obtain the second product.
According to one embodiment of the present invention, the step S1300 further includes an S1400 adsorption step: and (3) carrying out adsorption treatment on the second product by using macroporous adsorption resin and/or carbon nano adsorption resin until COD is less than 35mg/L, thereby obtaining a third product.
After subcritical water catalytic oxidation, small amounts of small molecular organic acids such as acetic acid and the like are also contained in the first product and the second product, and deep adsorption removal is carried out by adopting salt-tolerant organic acid removal resin. And (3) deeply removing a small amount of residual organic matters in the second product by adopting macroporous adsorption resin/carbon nano adsorption resin until COD is less than 35mg/L.
Preferably, the step S1400 further includes a catalyst regeneration recycling step after the adsorption step: and (3) regenerating the resin by using acid after the chelate resin is adsorbed and saturated, and returning the regenerated catalyst to the subcritical water catalytic oxidation system in the step S1200 for continuous use. The presence of the catalyst affects the lifetime of the subsequent salt separation membranes and bipolar membranes and therefore needs to be removed here in advance.
After adsorption, the catalyst ion concentration in the third product was <0.1mg/L (minimum to 0.02 mg/L), and the resin was allowed to calculate the regeneration time based on the adsorption capacity.
The raw water is chloride, the sulfate system adopts dilute hydrochloric acid or dilute sulfuric acid to desorb the dilute hydrochloric acid or dilute sulfuric acid, and then the raw water is directly returned to the subcritical water catalytic oxidation system for continuous use; the raw water is a nitrate system, the desorption is carried out by adopting dilute hydrochloric acid or dilute sulfuric acid, the pH of the desorption solution is regulated to 7-8, the catalyst cations form hydroxide precipitates, and the catalysts are reacted by adopting dilute nitric acid after the precipitates to become cation catalysts for recycling.
According to one embodiment of the present invention, the step S1400 further includes a step of S1500 salt separation treatment: and carrying out salt separation treatment on the third product to obtain a fourth product.
S1500 salt separation treatment: if the third product contains both chloride ions and sulfur elements, a membrane salt separation process can be used for separating chloride salts; if no salt partitioning is required, this step can be skipped.
If the third product contains both nitrate ions and sulfur elements, nitrate can be separated by adopting a membrane salt separation process; if no salt partitioning is required, this step can be skipped.
Salt separation refers to separation of sulfate and chloride/nitrate by adopting the characteristic of different charge interceptabilities of nanofiltration membranes.
According to one embodiment of the present invention, the step S1400 is followed by a first bipolar membrane treatment step S1610: and (3) performing bipolar membrane treatment on the third product to obtain acid, alkali and dilute brine.
Preferably, the dilute brine comprises brine with a mass percent concentration of <5%, and the dilute brine can be further concentrated by high pressure membranes or electrodialysis and returned to bipolar membrane treatment.
The acid and the alkali generated by the invention are dilute acid and dilute alkali with mass percent concentration of less than 5 percent respectively.
According to one embodiment of the present invention, the step S1500 further includes a step S1620 of second bipolar film treatment: and (3) carrying out bipolar membrane treatment on the fourth product to obtain acid, alkali and dilute brine.
S1620, a second bipolar membrane treatment step: and regulating the temperature of the purified fourth product to 25-40 ℃, entering a bipolar membrane system, transferring anions to produce acid, transferring cations to form liquid alkali, concentrating the produced dilute brine by adopting a reverse osmosis membrane, and continuing to return to the bipolar membrane to prepare the acid alkali. The bipolar membrane has low requirement on water inlet salt concentration and wider application range, the bipolar membrane has relatively low water inlet condition, no requirement on almost no COD, the bipolar membrane generates acid and alkali, the concentration is adjustable, and the ionic membrane also generates chlorine and hydrogen. And concentrating the produced acid and alkali respectively to obtain qualified products.
According to one embodiment of the invention, the temperature of the third or fourth product is adjusted to 25-40 ℃ before entering bipolar membrane treatment.
According to one embodiment of the present invention, the step S1610 or S1620 further comprises the steps of concentrating and recycling S1700 acid, alkali and dilute brine: concentrating the acid and the alkali obtained by bipolar membrane treatment for industrial production and/or sale; after concentrating the dilute brine, the process returns to step S1610 or S1620 again to perform bipolar membrane treatment so as to prepare the acid and the base.
The invention relates to a treatment process of high-salt organic wastewater, which is used for recycling the wastewater to generate acid-base products. The process adopts a subcritical water catalytic oxidation process as a core, and is coupled with a pretreatment process and a bipolar membrane process to treat high-salt organic wastewater. The invention has simple process flow, high treatment efficiency and small occupied area; the operation cost is greatly reduced compared with the traditional process; the byproduct acid and alkali can also produce byproducts. The process has the advantages of being green, circular and economical, and is easy for enterprises to popularize.
Drawings
Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the invention. Also, like reference numerals are used to designate like parts throughout the figures. Wherein in the drawings, letter designations after reference numerals indicate like elements, and when broadly referred to, last letter designations thereof will be omitted. In the drawings:
FIG. 1 illustrates a method of treating high salt organic wastewater according to a preferred embodiment of the present invention;
FIG. 2 illustrates a method of treating high salt organic wastewater according to a preferred embodiment of the present invention;
FIG. 3 illustrates a method of treating high salt organic wastewater according to a preferred embodiment of the present invention; and
Fig. 4 shows a block flow diagram of a method of treating high-salt organic wastewater.
Detailed Description
The invention provides many applicable inventive concepts that can be embodied in a wide variety of specific contexts. The specific examples described in the following embodiments of the present invention are merely illustrative of the specific embodiments of the present invention and do not constitute a limitation on the scope of the invention.
The invention is further described below with reference to the drawings and detailed description.
Fig. 1 illustrates a method of treating high-salt organic wastewater according to a preferred embodiment of the present invention. As shown in FIG. 1, the method for treating high-salt organic wastewater provided by the invention comprises an S1200 catalytic oxidation step, an S1300 catalyst removal step and an S1400 adsorption step.
Since the salt separation treatment step S1500 may be optionally applied according to circumstances, when salt separation is not required, as shown in fig. 2, the adsorption step S1400 further includes a first bipolar membrane treatment step S1610, a step of concentrating and recycling the alkali and dilute brine.
When salt separation is required, for example, the water contains both nitrate ions and sulfur, then a membrane salt separation process can be used to separate nitrate, as shown in fig. 3, and the adsorption step S1400 further includes a step of S1500 salt separation treatment, a step of S1620 second bipolar membrane treatment, a step of S1700 acid, alkali, and a step of dilute brine concentration and recycling.
Fig. 4 shows a block flow diagram of the method of treating high-salt organic wastewater comprising the salt-splitting treatment step of fig. 3. The method for treating high-salt organic wastewater provided by the present invention will be explained with reference to fig. 4.
The high-salt organic wastewater comprises soluble organic matters, solid particles and at least one of the following salts with the mass percentage concentration of 5-22 percent: chloride, sulfate, nitrate.
As shown in fig. 4, the method for treating high-salt organic wastewater provided by the invention comprises the following steps: first, the step S1100 of preprocessing is entered: before the subcritical water catalytic oxidation treatment of the high-salt organic matter wastewater, removing one or more of the following ions by a resin adsorption or flocculation precipitation method: calcium ion, magnesium ion, silicate ion, and fluoride ion.
Preferably, solid particles in the high-salt organic wastewater are removed. Preferably, solid particles in the high-salt organic matter wastewater and particle solids generated by flocculation precipitation are filtered by methods of filter pressing, automatic back flushing filter, ultrafiltration and the like, and the filtering precision is 0.1-100 microns.
Then enter S1200 and catalyze the oxidation step: and carrying out subcritical water catalytic oxidation treatment on the high-salt organic matter wastewater to obtain a first product.
And then the step S1300 of catalyst removal is carried out: and (3) adsorbing the first product by using chelating resin to remove the catalyst, so as to obtain a second product.
Then, the process goes to S1400 adsorption step: and (3) carrying out adsorption treatment on the second product by using macroporous adsorption resin and/or carbon nano adsorption resin until COD is less than 35mg/L, thereby obtaining a third product.
And then the step S1500 of salt separation treatment is carried out: and carrying out salt separation treatment on the third product to obtain a fourth product.
According to other embodiments, the step of salt splitting treatment is skipped S1500 when salt splitting treatment is not required. As shown in fig. 2, the bipolar membrane treatment step is directly entered after the adsorption step S1400, and the step S1610 is entered after the adsorption step S1400: and (3) performing bipolar membrane treatment on the third product to obtain acid, alkali and dilute brine.
According to this embodiment, preferably, as shown in fig. 4, the third product is subjected to salt separation treatment to obtain a fourth product. The fourth product comprises chloride, sulfate and nitrate. Then, the process goes to the second bipolar film processing step in S1620: and regulating the temperature of the purified fourth product to 25-40 ℃, entering a bipolar membrane system, and respectively carrying out bipolar membrane treatment on the chloride, sulfate and nitrate of the fourth product to obtain dilute hydrochloric acid and dilute alkali (sodium hydroxide/potassium hydroxide), dilute sulfuric acid and dilute alkali (sodium hydroxide/potassium hydroxide), and dilute nitric acid and dilute alkali (sodium hydroxide/potassium hydroxide). The anions migrate to produce acid and the cations migrate to form liquid base.
Preferably, the method finally enters the steps of S1700 acid, alkali and dilute brine concentration and recycling: concentrating the acid and the alkali obtained by bipolar membrane treatment for industrial production and/or sale; after concentrating the dilute brine, the process returns to step S1620 again to perform bipolar membrane treatment so as to prepare the acid and the base.
Preferably, the produced dilute brine is concentrated by adopting a reverse osmosis membrane and is continuously returned to the bipolar membrane for preparing acid and alkali. The bipolar membrane has low requirement on water inlet salt concentration and wider application range, the bipolar membrane has relatively low water inlet condition, no requirement on no COD basically, the bipolar membrane generates acid and alkali, the concentration is adjustable, and the produced acid and alkali are respectively concentrated to become a qualified product.
In general, the subcritical water catalytic oxidation treatment of the high-salt organic matter wastewater is carried out to obtain a first product; adsorbing the first product by chelating resin to remove the catalyst, thereby obtaining a second product; adsorbing the second product by using macroporous adsorption resin or carbon nano adsorption resin to obtain a third product; salt separation treatment is carried out on the third product to obtain a fourth product; and (3) carrying out bipolar membrane treatment on the fourth product to obtain acid, alkali and dilute brine. Concentrating the acid and the alkali obtained by bipolar membrane treatment for industrial production and/or sale; after concentrating the dilute brine, the process returns to step S1620 again to perform bipolar membrane treatment so as to prepare the acid and the base.
The method for treating the high-salt organic wastewater has the beneficial effects that:
1. the high-salt water is subjected to subcritical water catalytic oxidation to remove more than 98% of organic matters, so that the salt water can be recycled.
2. In the subcritical water catalytic oxidation process, substances harmful to the material of the bipolar membrane, such as solvents, are removed, and stable operation of the bipolar membrane process is ensured.
3. The water quality after subcritical water catalytic oxidation is treated by adopting a bipolar membrane process, and a value byproduct is generated. The energy consumption of normal temperature treatment is low, and the waste of resources of waste salt landfill after evaporation is avoided.
In the method for preparing the high-salt organic wastewater, more than 98% of organic matters are removed from the high-salt water through subcritical water catalytic oxidation, so that the salt water can be recycled. Examples 1 to 8 are provided below for the process of removing organics in the high salt organic wastewater treatment method, and the organic removal effect was tested, and the results are shown in table 1.
Examples 1 to 9
The high-salt organic wastewater comprises soluble organic matters and salt with the mass percentage concentration of 5-22%. S1200, catalytic oxidation step: carrying out subcritical water catalytic oxidation treatment on the high-salt organic matter wastewater to obtain a first product; wherein the subcritical water catalytic oxidation treatment comprises: and (3) regulating the pH value of the high-salt organic matter wastewater to be 2-5, adding a catalyst, and carrying out subcritical water catalytic oxidation under the conditions of the reaction temperature of 200-300 ℃ and the reaction pressure of 5-20 Mpa.
TABLE 1 removal of COD by subcritical Water Oxidation
The process providing examples of the high salt organic wastewater treatment process are further described below:
example 10 [ no salt separation treatment is required ]
As shown in fig. 2, when the high-salt organic wastewater contains only one salt, the salt separation treatment is not required. Therefore, the method firstly enters the step of S1100 pretreatment, and then sequentially enters the step of S1200 catalytic oxidation, the step of S1300 catalyst removal, the step of S1400 adsorption, the step of S1610 first bipolar membrane treatment, the step of S1700 acid, alkali and dilute brine concentration and recycling.
The high-salt wastewater generated in the neutralization process of the production process of a certain enterprise has 100t/d, COD of 30000-40000 mg/L and sodium sulfate of 12-17%, soft water is adopted in the production process, and no calcium, magnesium and silicon and a small amount of solid particles are adopted. Filtering water quality by a cartridge filter, regulating the pH value to 3, adding 500mg/L copper catalyst (calculated by copper ions) into the water, heating, and then, entering a reactor for reaction at 270 ℃ under 7Mpa; cooling the reaction effluent to 40 ℃, and removing copper ions to below 1mg/L by chelating resin, wherein the COD of the effluent is 400-600 mg/L; COD is adsorbed to below 100mg/L through two-stage adsorption resin; then the water is supplemented by 167t/h through a bipolar membrane to generate 9%130t/d of dilute sulfuric acid and 7%137t/d of dilute alkali solution; the generated dilute sulfuric acid adopts 0.6Mpa steam to concentrate the dilute sulfuric acid to 75 percent, and the dilute sulfuric acid is recycled for industrial production; the diluted alkali liquor is concentrated to 30% by adopting steam and reused for industrial production. The resulting 5% sodium sulfate was concentrated to 12% and returned to bipolar membrane treatment again to prepare sulfuric acid and sodium oxide.
Example 11 [ salt separation treatment is required ]
As shown in fig. 3, when the high-salt organic wastewater contains two or more salts, it is necessary to perform salt separation treatment. Therefore, the method firstly enters the step of S1100 pretreatment, and then sequentially enters the step of S1200 catalytic oxidation, the step of S1300 catalyst removal, the step of S1400 adsorption, the step of S1500 salt separation treatment, the step of S1620 second bipolar membrane treatment, the step of S1700 acid, alkali and dilute brine concentration and recycling.
300T/d of high-salt wastewater generated in the neutralization process of the production process of a certain enterprise, 15000-20000 mg/L of COD, 0.5% of sodium sulfate, 9% of sodium chloride, high water hardness and 800-1000 mg/L of hardness (calculated by calcium carbonate). Adjusting pH to 10.5, adding lime to remove calcium and magnesium, adding silicon to remove magnesium, and removing solid particles by tubular ultrafiltration to obtain water with hardness less than 20mg/L. Filtering water by a cartridge filter, regulating the pH to 3, adding 1000mg/L zinc catalyst (zinc chloride, calculated as zinc ions), heating, and then entering a reactor for reaction at 280 ℃ under 9Mpa; cooling the reaction effluent to 28 ℃, and removing copper ions to below 0.5mg/L by two stages of chelating resin with effluent COD of 200-300 mg/L; through two-stage adsorption resin, COD is adsorbed to below 100mg/L, sodium sulfate is concentrated to 8% by adopting nanofiltration membrane salt separation technology, and a bipolar membrane removing process is carried out on sodium chloride solution of 280t/d generated by membrane fresh water measurement. The bipolar membrane is supplemented with water for 215t/h to generate 8%323t/d of diluted hydrochloric acid and 10%172t/d of diluted alkali liquor; brine produced by the bipolar membrane is concentrated by adopting a reverse osmosis membrane, and concentrated solution is returned to the inlet of the bipolar membrane for treatment. The produced dilute hydrochloric acid adopts 0.4Mpa steam to concentrate the dilute hydrochloric acid to 30%, and the dilute hydrochloric acid is recycled for industrial production, and adopts the steam to concentrate the dilute alkali liquor to 30%, and is recycled for industrial production.
It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word "comprising" does not exclude the presence of elements or steps not listed in a claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The use of the words first, second, third, etc. do not denote any order. These words may be interpreted as names.

Claims (10)

1. A method for treating high-salt organic wastewater, wherein the high-salt organic wastewater comprises soluble organic matters and at least one of the following salts with the mass percent concentration of 5% -22%: chlorine salt, sulfate and nitrate,
The method for treating the high-salt organic wastewater comprises the following steps of:
(S1200) a catalytic oxidation step: carrying out subcritical water catalytic oxidation treatment on the high-salt organic matter wastewater to obtain a first product;
wherein the subcritical water catalytic oxidation treatment comprises: and (3) regulating the pH value of the high-salt organic matter wastewater to be 2-5, adding a catalyst, and carrying out subcritical water catalytic oxidation under the conditions of the reaction temperature of 200-300 ℃ and the reaction pressure of 5-20 Mpa.
2. The method for treating high-salt organic wastewater according to claim 1, wherein (S1200) the catalyst comprises at least one of: manganese ions, cobalt ions, cadmium ions, zinc ions, and copper ions;
The concentration of the catalyst is 50-2000mg/L.
3. The method for treating high-salt organic wastewater according to claim 1, further comprising (S1100) a pretreatment step before the (S1200) step: before the subcritical water catalytic oxidation treatment of the high-salt organic matter wastewater, removing one or more of the following ions by a resin adsorption or flocculation precipitation method: calcium ion, magnesium ion, silicate ion, and fluoride ion.
4. The method for treating high-salt organic wastewater according to claim 1, further comprising, after the (S1200) step:
(S1300) a catalyst removal step: and (3) adsorbing the first product by using chelating resin to remove the catalyst, so as to obtain a second product.
5. The method for treating high-salt organic wastewater as claimed in claim 4, further comprising, after the step of (S1300)
(S1400) adsorption step: and (3) carrying out adsorption treatment on the second product by using macroporous adsorption resin and/or carbon nano adsorption resin, and carrying out adsorption treatment on the second product by using macroporous adsorption resin and/or carbon nano adsorption resin until COD is less than 35mg/L, thereby obtaining a third product.
6. The method for treating high-salt organic wastewater according to claim 5, further comprising, after the step of (S1400)
(S1500) salt separation treatment: and carrying out salt separation treatment on the third product to obtain a fourth product.
7. The method for treating high-salt organic wastewater according to claim 5, further comprising, after the step (S1400)
(S1610) a first bipolar membrane treatment step: and (3) performing bipolar membrane treatment on the third product to obtain acid, alkali and dilute brine.
8. The method for treating high-salt organic wastewater according to claim 6, further comprising, after the step of (S1500)
(S1620) a second bipolar membrane processing step: and (3) carrying out bipolar membrane treatment on the fourth product to obtain acid, alkali and dilute brine.
9. The method for treating high-salt organic wastewater according to claim 7 or 8, wherein the temperature of the third or fourth product is adjusted to 25-40 ℃ before proceeding to bipolar membrane treatment in the step (S1610) or (S1620).
10. The method for treating high-salt organic wastewater according to claim 7 or 8, further comprising (S1700) an acid, base, dilute brine concentration and recycling step after the step of (S1610) or (S1620):
concentrating the acid and the alkali obtained by bipolar membrane treatment for industrial production and/or sale;
After concentrating the dilute brine, the process returns to (S1610) or (S1620) step again for bipolar membrane treatment to prepare the acid and the base.
CN202410481702.XA 2024-04-22 2024-04-22 Method for treating high-salt organic wastewater Pending CN118458978A (en)

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