CN115072925A - A kind of treatment method of high-concentration organic wastewater containing organic/inorganic double salt - Google Patents

Abstract

The invention belongs to the technical field of high-concentration salt-containing organic wastewater treatment, and in particular relates to a treatment method for high-concentration organic/inorganic double-salt-containing organic wastewater. The high-concentration organic wastewater containing organic/inorganic double salts is sent to the neutralization reaction separator to adjust its pH, and the oil phase, solid phase or gas phase decomposed by organic salts are separated, and the water phase is sent to the multi-stage adsorption/gas phase equipped with different adsorbents. The desorption column absorbs and removes the organic matter contained in the waste water, and the discharged adsorption liquid is sent to the inorganic salt recovery to obtain the industrial grade inorganic salt product, and the residual mother liquor is recycled back to the waste water tank. When the adsorption of the adsorbent in the multi-stage adsorption/desorption column is close to saturation, desorb with the desorbent, and the desorbed liquid is sent to the desorbent recovery tower to recover the desorbent, and the organic waste liquid after removing the desorbent or recycled Refined, or incinerated, or sent to sewage biochemical treatment. The method has the advantages of high quality of recovered inorganic salt, thorough treatment of organic matter, recycling of adsorbent and desorbent, and thorough treatment of wastewater.

Description

A kind of treatment method of organic wastewater containing organic/inorganic double salt with high concentration

technical field

The invention belongs to the technical field of high-concentration salt-containing organic wastewater treatment, in particular to a treatment method for high-concentration organic/inorganic double-salt-containing organic wastewater.

Background technique

High-concentration organic/inorganic double salt organic wastewater comes from chemical industry (especially fine chemical industry), food processing, printing and dyeing and other industries, because it contains not only inorganic salts, but also organic salts, and the salt concentration is high, and contains various properties, Organic impurities with complex, toxic and harmful components are difficult to be directly treated by general biochemical methods, evaporation methods and membrane separation methods. Currently, the following two methods are generally used:

(1) Incineration method, high temperature combustion in a special incinerator, high investment in the incinerator, high energy consumption for high temperature incineration, easy corrosion and damage to the incinerator, organic matter containing N, P, S and other elements, combustion is easy to generate NOx, POx and SOx, It is easy to cause secondary pollution;

(2) Advanced oxidation method: Fenton oxidation, photocatalytic oxidation, electrochemical oxidation, sonochemical oxidation and other methods are used to degrade organic matter in wastewater. Due to the high chlorine content in high-salt wastewater, the oxidative degradation effect is inhibited. In addition, organic impurities generally contain sulfur , nitrogen, phosphorus and other elements, the oxidation also produces SOx, NOx and POx, causing secondary pollution.

Therefore, this type of wastewater treatment is the most difficult at present, and it is an urgent issue for related enterprises to solve.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is: the existence and influence of organic salts in waste water are neglected in the existing salt-containing waste water treatment technology, which leads to the negative influence of organic salts on the waste water treatment effect, such as it is difficult to completely remove and recover organic impurities in waste water. The quality of salt is greatly reduced, etc.

A method for treating high-concentration organic/inorganic double-salt organic wastewater provided by the present invention comprises the following steps:

(1) Pump the high-concentration organic wastewater containing organic/inorganic double salts to the neutralization reaction separator, and adjust the pH of the wastewater with acid or alkali reagents to decompose the organic salts into inorganic salts and organic matter to the maximum extent; , organic matter and inorganic salts that may form a second phase, such as oil phase, solid phase or gas phase, separated from the water phase;

Among them, the mass content of inorganic salts and organic salts in the high-concentration organic wastewater containing organic/inorganic double salts is higher than 2%, the total salt content is higher than 5%, and the chemical oxygen consumption COD is higher than 4000mg/mL;

Acids or alkalis are reagents that can form inorganic salts with inorganic acid radicals or inorganic bases of organic salts in wastewater; organic salts will decompose to form organic and inorganic salts during the pH adjustment process of wastewater. The variety of salt, adjust the end point of pH as much as possible to maximize the conversion of organic salts into organic and inorganic salts. The hydrolysis of organic salts during pH adjustment may produce second phase organic matter and inorganic salts, such as oil phase, solid phase or gas phase, in this case, the second phase needs to be separated separately.

(2) The water phase of step (1) is sent to the multi-stage adsorption/desorption column, and adsorbed in contact with the adsorbent. The adsorbents used in the adsorption columns at all levels are generally different and can adsorb different organic components in the wastewater. The adsorption liquid is discharged from the first-stage adsorption column; the discharged adsorption liquid is sent to recover inorganic salts, and the remaining residual mother liquor is sent to the waste water tank for recycling;

The multistage adsorption/desorption column consists of 2-5 stages;

The adsorbent is preferably selected from macroporous resins and their modifications, cross-linked or hypercross-linked resins, activated carbon, molecular sieves, silica gel, graphene and their modifications and other adsorbent materials.

To recover inorganic salts, methods such as membrane separation, ion exchange, or evaporation, crystallization, filtration and drying can be used.

(3) desorbing the adsorbent near saturation in the multi-stage adsorption/desorption column of step (2) with a desorbent to obtain a desorbed liquid, regenerate the adsorbent, and recycle it for step (2); The desorbent obtained in step (2) is sent to the desorbent recovery tower, which is a rectifying tower, and the desorbent is reclaimed at the top of the tower, and the recovered desorbent can be recycled for step (3), Aqueous organic waste liquid is discharged from the bottom of the tower;

The desorbent is generally a low-carbon organic solvent or solution, and its dosage is 2-6 times the volume of the adsorbent.

The reflux ratio in the rectification process is determined by the process economy, the top temperature is determined by the distillate azeotrope or the purity of the solvent, and the tower kettle temperature is determined by the composition of the organic matter in the kettle and the thermal energy utilization efficiency.

(4) The organic waste liquid obtained in step (3) can be recycled and refined, or incinerated, or sent to sewage biochemical treatment according to its composition, characteristics, utilization value and economy.

Aiming at the problems existing in the treatment process of high-concentration organic/inorganic double-salt organic wastewater and the characteristics of this type of wastewater, the present invention provides a high-concentration organic/inorganic double-salt-containing organic wastewater treatment method for treating this type of wastewater. There are 3 key issues to solve:

(1) The principle of utilizing organic salts to dissociate at different pHs to get rid of organic and inorganic salts uses acid or alkali reagents to decompose organic salts in wastewater into organic and inorganic salts;

(2) The organic matter and inorganic salt formed after the decomposition of the organic salt may be insoluble in the original wastewater to form a second phase, which can be separated and recovered separately;

(3) Use multi-stage adsorption/desorption columns containing different adsorbents to completely or nearly completely adsorb organic matter with different properties and complex components in wastewater.

Therefore, the organic matter in the wastewater is completely or nearly completely removed, and the adsorption liquid basically does not contain organic impurities, so the industrial-grade inorganic salts can be recovered. When the adsorbent is close to saturated adsorption, desorb with a low-carbon organic solvent or solution to regenerate the adsorbent and recycle it. The desorbent is recovered by rectification, so that the desorbent can be recycled, and the residual organic waste liquid can be recovered and refined, or incinerated, or sent to sewage biochemical treatment, which can not only greatly reduce the impact of such wastewater on the environment, but also And part of the organic matter and inorganic salts can be recovered.

Compared with the prior art, the high-concentration organic/inorganic double salt-containing organic wastewater treatment method of the present invention has the following advantages:

(1) the used pH-adjusting neutralization method makes the organic salt be converted into organic matter and inorganic salt, and overcomes the shortcoming that it is difficult to handle the organic salt when the conventional salt-containing wastewater treatment method and the inorganic salt are recovered;

(2) The possible second-phase organics and inorganic salts obtained from the conversion of organic salts in wastewater can be recovered separately to obtain product benefits;

(3) Multi-stage adsorption with different adsorbents can completely or nearly completely remove various organic substances in organic wastewater with complex components;

(4) Because the organic matter in the wastewater is removed to the greatest extent, the impurity content of the inorganic salt obtained by the subsequent recovery of the inorganic salt is greatly reduced, and the purity is greatly improved;

(5) After the desorbent is recovered from the desorbent, the organic waste liquid is greatly concentrated, and can be recycled and refined, or incinerated, or sent to sewage treatment according to the organic composition, value and economy contained in it;

(6) The system and process of the present invention have a very good treatment effect on the high-concentration organic/inorganic double-salt organic wastewater containing extremely difficult oils, benzene rings, biphenyls, heterocycles, azos, etc. High efficiency and moderate cost.

Description of drawings:

1 is a process flow diagram of a method for treating high-concentration organic/inorganic double salt-containing organic wastewater in Example 1 of the present invention.

Detailed ways

The present invention will be further described in detail below in conjunction with specific embodiments.

Example 1

The high-concentration organic wastewater containing organic/inorganic double salts in this example is taken from an agricultural chemical company, the inorganic salt is sodium chloride, the organic salt is triethylamine hydrochloride, the organic impurities are complex, and the COD is 33,200 mg/L , ammonia nitrogen was 580mg/L, pH was 2.5, and it was brown.

As shown in Figure 1, the high-concentration organic/inorganic double salt-containing organic wastewater treatment device includes a pump, a neutralization reaction separator, a multi-stage adsorption/desorption column, an MVR evaporator, a crystallization kettle, a filter, a dryer, Desorbent recovery tower and organic waste liquid tank, etc.

The wastewater was pumped into the neutralization reaction separator, and the pH was adjusted to 9 with 35% sodium hydroxide solution. After adjusting the pH, the organic salt triethylamine hydrochloride will be decomposed into sodium chloride and triethylamine, and the triethylamine oil phase will be formed, and the upper oil phase will be separated (gravity stratification, pipe flow output). The lower water phase is adsorbed in series with ^three -stage adsorption/desorption columns composed of three different adsorbents. /Desorption column was loaded with macroporous resin XAD-4 (120kg/ ^m3 waste water), and tertiary adsorption/desorption column was loaded with porous graphene (60kg/ ^m3 waste water). The aqueous phase flows in from the primary adsorption/desorption column and flows out from the tertiary adsorption/desorption column. After the three-stage adsorption/desorption column treatment, the COD of the adsorption liquid was reduced to 95 mg/L, the ammonia nitrogen was reduced to 0 mg/L, and the adsorption liquid was a colorless and transparent liquid. The adsorption liquid is sent to the MVR evaporator for atmospheric evaporation, the temperature of the evaporator does not exceed 180 ℃, concentrated to the sodium chloride content of 70%, sent to the crystallization kettle, stirred and cooled for crystallization, and then filtered with a filter, and the filter cake is washed with water to remove Dry in a desiccator to obtain industrial sodium chloride salt (purity>97%), and return the filtrate and washing liquid to the waste water tank for recycling.

The first-stage adsorption/desorption column, the second-stage adsorption/desorption column and the third-stage adsorption/desorption column whose adsorption is close to saturation are desorbed with 40% ethanol solution respectively. The desorbent flows in from the top of the column and flows out from the bottom of the column. The desorption dose is 4 times the bed volume, and the obtained desorption liquid is sent to the desorption agent recovery tower. The recovery tower is a continuous rectification tower. The temperature of the kettle is not more than 150°C, and the ethanol-water azeotrope (ethanol content 95%) is obtained at the top of the tower. After adding water to make up to 40%, it can be recycled as a desorbent for a three-stage adsorption/desorption column, and the tower kettle discharges water-containing organic matter. waste liquid. This organic waste liquid can be mixed with other waste water from the factory for biochemical treatment.

After the method of the invention, the COD of the wastewater is reduced from 33,200mg/L to 95mg/L before entering the MVR evaporator, the ammonia nitrogen is reduced to 0mg/L, the sodium chloride is basically completely recovered, the organic matter removal rate is more than 99%, and the desorption The recycling rate of the agent is >93%.

Example 2

The high-concentration organic wastewater containing organic/inorganic double salts in this example is taken from a fine chemical company, the inorganic salt is mainly magnesium chloride, and contains a small amount of sodium chloride, the organic salt is dimethylamine hydrochloride, and the organic impurities are complex , COD is 22,000mg/L, ammonia nitrogen is 280mg/L, pH is 3, it is light yellow transparent liquid.

The high-concentration organic/inorganic double salt-containing organic wastewater treatment device is the same as in Example 1.

The waste water is sent to the neutralization reaction separator with a pump, and 35% sodium hydroxide solution is added dropwise under stirring to adjust the pH to 7, and absorption or collection (absorption with water or ethanol, or condensed to below 6 °C to form a liquid collection) II The volatile dimethylamine gas generated by the decomposition of methylamine hydrochloride, the water phase is adsorbed in series with three-stage adsorption/desorption columns composed of three different adsorbents, wherein the first-stage adsorption/desorption column is equipped with macroporous resin NKA-II (120kg/ ^m3 waste water), secondary adsorption/desorption column was filled with macroporous resin XAD-4 (80kg/ ^m3 waste water), tertiary adsorption/desorption column was filled with graphene oxide (40kg/m3 ³ waste water). The aqueous phase is introduced from the primary adsorption/desorption column and discharged from the tertiary adsorption/desorption column. After the three-stage adsorption/desorption column adsorption treatment, the COD of the adsorption liquid was reduced to 130 mg/L, the ammonia nitrogen was reduced to 0 mg/L, and the adsorption liquid was a colorless and transparent liquid. The adsorption liquid is sent to the MVR evaporator for atmospheric evaporation, the temperature of the evaporator does not exceed 170 ° C, concentrated to the magnesium chloride content of 65%, and then the concentrated liquid is sent to the crystallization kettle, stirred and cooled for crystallization, and filtered with a filter. Washing and drying in a desiccator to obtain a mixed salt of magnesium chloride and sodium chloride (magnesium chloride content 83.3%, sodium chloride content 12%), separated by elution method to obtain technical grade magnesium chloride and sodium chloride, the filtrate and washing liquid are returned to the waste water tank for circulation deal with.

The first-stage adsorption/desorption column, the second-stage adsorption/desorption column and the third-stage adsorption/desorption column whose adsorption is close to saturation are desorbed with 40% ethanol solution respectively. The desorbent flows in from the top of the column and flows out from the bottom of the column. The desorption dose was 5 times the bed volume. The obtained desorption liquid is sent to the desorbent recovery tower, which is a continuous rectification tower, the reflux ratio is controlled at 2, the temperature at the top of the tower is controlled at 79.3±1°C, and the temperature of the tower still is controlled not to exceed 180°C. Ethanol-water azeotrope (ethanol content 95%), after adding water to make 40%, can be recycled as the desorbent of the three-stage adsorption/desorption column, and the water-containing organic waste liquid is discharged from the tower kettle. This organic waste liquid can be mixed with other waste water from the factory and then enter the biochemical treatment device.

Through the treatment of the method of the invention, the COD of the wastewater is reduced from 22,000mg/L to 130mg/L before entering the MVR evaporator, the ammonia nitrogen is reduced to 0mg/L, the magnesium chloride and sodium chloride can be recovered almost completely, and the organic matter removal rate is >98%, The recycling rate of desorbent is >94%.

Example 3

The high-concentration organic wastewater containing organic/inorganic double salts in this example is taken from a fine chemical company, the inorganic salt is ammonium chloride, the organic salt is an organic acid ammonium salt, the organic impurities are complex, the COD is 25,000 mg/L, and the pH is 10.5, which is gray.

The high-concentration organic/inorganic double salt-containing organic wastewater treatment device is the same as in Example 1.

The waste water is sent to the neutralization reaction separator with a pump, and 30% hydrochloric acid is added to adjust the pH to 7 under stirring conditions. At this time, no second phase is generated. The neutralization liquid is composed of three different adsorbents. Attached column series adsorption, wherein, the primary adsorption/desorption column is equipped with macroporous resin H103 (150kg/ ^m3 waste water), and the secondary adsorption/desorption column is equipped with macroporous resin NKA-II (100kg/ ^m3 waste water) , the three-stage adsorption/desorption column is equipped with AB-8 (80kg/ ^m3 waste water), and the aqueous phase is introduced from the first-stage adsorption/desorption column and discharged from the third-stage adsorption/desorption column. After three-stage adsorption/desorption column adsorption treatment, the COD of the adsorption liquid was reduced to 102 mg/L, and the adsorption liquid was a colorless and transparent liquid. The adsorption liquid is sent to the MVR evaporator for atmospheric evaporation, the temperature of the evaporator does not exceed 150 ℃, concentrated to 75% of the ammonium chloride content, sent to the crystallization kettle, stirred and cooled for crystallization, and then filtered with a filter, and the filter cake is washed with water to remove The dryer is dried to obtain industrial ammonium chloride salt (content of ammonium chloride is 97%), and the filtrate and washing liquid are returned to the waste water tank for recycling treatment.

The first-stage adsorption/desorption column, the second-stage adsorption/desorption column and the third-stage adsorption/desorption column whose adsorption is close to saturation are desorbed with 70% acetone solution respectively. The desorbent flows in from the top of the column and flows out from the bottom of the column. The desorption dose was 5 times the bed volume. The obtained desorption liquid is sent to the desorbent recovery tower, which is a continuous atmospheric rectification tower, the reflux ratio is controlled at 1.5, the temperature at the top of the tower is controlled to be less than 60°C, and the temperature of the tower kettle is controlled not to exceed 150°C. >70% acetone solution, which can be recycled as the desorbent of the three-stage adsorption/desorption column, and the aqueous organic waste liquid is discharged from the tower kettle. This organic waste liquid can be mixed with other waste water from the factory and then enter the biochemical treatment device.

After treatment by the method of the invention, the COD of the wastewater is reduced from 25,000mg/L to 102mg/L entering the MVR evaporator, the ammonium chloride is nearly completely recovered, the organic matter removal rate is >98%, and the desorbent recycling rate is >93%.

Example 4

The high-concentration organic wastewater containing organic/inorganic double salts in this example is the same as that in Example 1.

The high-concentration organic/inorganic double-salt-containing organic wastewater treatment device is the same as Example 1, except that the multi-stage adsorption/desorption column adopts a two-stage adsorption/desorption column.

The wastewater was pumped into the neutralization reaction separator, and the pH was adjusted to 9 with 35% sodium hydroxide solution. After adjusting the pH, the organic salt triethylamine hydrochloride will be decomposed into sodium chloride and triethylamine, and the triethylamine oil phase will be formed, and the upper oil phase will be separated. The lower water phase is adsorbed in series with two ^- stage adsorption/desorption columns composed of two different adsorbents. /The desorption column was loaded with macroporous resin XAD-4 (120kg/ ^m3 waste water). After the secondary adsorption/desorption column treatment, the COD of the adsorption liquid was reduced to 2650 mg/L, the ammonia nitrogen was reduced to 0 mg/L, and the adsorption liquid was a colorless and transparent liquid. The COD removal rate of the adsorption liquid is 92%, and the ammonia nitrogen is completely removed. The salt quality of subsequent sodium chloride salt recovery is slightly lower than that of Example 1.

It can be seen from Example 4 that after the organic salt of the original wastewater is converted, when the number of adsorption stages in the multi-stage adsorption performed by the subsequent multi-stage adsorption/desorption column is reduced, the COD removal rate of the wastewater will decrease to a certain extent, which is disadvantageous for the subsequent recovery of inorganic salts. .

Comparative Example 1

The high-concentration organic wastewater containing organic/inorganic double salts in this example is the same as in Example 2.

This high-concentration organic/inorganic double-salt-containing organic wastewater treatment device has no neutralization reaction separation step, and the others are the same as in Example 2.

The wastewater is directly sent into the three-stage adsorption/desorption column series adsorption composed of three different adsorbents with a pump, wherein, the first-stage adsorption/desorption column is equipped with macroporous resin NKA-II (120kg/ ^m Wastewater), The secondary adsorption/desorption column was filled with macroporous resin XAD-4 (80kg/ ^m3 waste water), and the tertiary adsorption/desorption column was filled with graphene oxide (40kg/ ^m3 waste water). After the three-stage adsorption/desorption column treatment, the COD of the adsorption liquid was reduced to 3,150 mg/L, and the ammonia nitrogen was reduced to 152 mg/L. The COD removal rate of the adsorption liquid is only 85.7%, the ammonia nitrogen removal rate is only 45.8%, and its organic salt content is basically unchanged, so high-quality magnesium chloride salt cannot be recovered. The high-concentration organic/inorganic double-salt-containing organic wastewater is not completely treated.

It can be seen from Comparative Example 1 that the organic salts in the wastewater are not converted by pH adjustment, and the subsequent adsorption treatment process cannot remove the organic salts, which will cause the effect of recovering the inorganic salts to fail to reach the expected target.

Comparative Example 2

The high-concentration organic wastewater containing organic/inorganic double salts in this example is the same as in Example 2.

The high-concentration organic/inorganic double salt-containing organic wastewater treatment device is the same as in Example 2.

The wastewater was sent to the neutralization tank with a pump, and the pH was adjusted to 5 with 35% sodium hydroxide solution, and no second phase of triethylamine appeared, and the single-stage adsorption containing macroporous resin XAD-4 (80kg/ ^m3 wastewater) was used. /Desorption column treatment, the COD of the adsorption liquid is still as high as 17,400mg/L, the ammonia nitrogen is 403mg/L, the color is light yellow, the organic content of the treated water is too high, the content of triethylamine hydrochloride is still high, and the sodium chloride salt is recovered in the follow-up. The color is yellow and the impurity content is high. Wastewater treatment and industrial inorganic salt recovery failed.

It can be seen from Comparative Example 2 that adjusting the pH of the wastewater to convert organic salts into inorganic salts and organic matter as much as possible and adopting combined adsorbent adsorption are crucial to the successful application of the technology of the present invention. Recovery of inorganic salts is also impossible.

Comparative Example 3

The high-concentration organic wastewater containing organic/inorganic double salts in this example is the same as that in Example 1.

The high-concentration organic/inorganic double-salt-containing organic wastewater treatment device is the same as Example 1, except that the multi-stage adsorption/desorption column adopts a one-stage adsorption/desorption column.

The wastewater was pumped into the neutralization reaction separator, and the pH was adjusted to 9 with 35% sodium hydroxide solution. After adjusting the pH, the organic salt triethylamine hydrochloride will be decomposed into sodium chloride and triethylamine, and the triethylamine oil phase will be formed, and the upper oil phase will be separated. The lower water phase is adsorbed by a macroporous resin NKA-II (180kg/ ^m3 waste water) for first-stage adsorption/desorption column adsorption, the COD of the discharged adsorption liquid is reduced to 15600mg/L, the ammonia nitrogen is reduced to 420mg/L, and the adsorption liquid is Brown liquid. The COD removal rate of the adsorption liquid was 53%, and the ammonia nitrogen removal rate was 27.6%. High-quality inorganic salts cannot be recovered due to still high levels of organic impurities.

It can be seen from Comparative Example 3 that after converting the organic salt of the original wastewater, when the subsequent multi-stage adsorption/desorption column is changed to a single-stage adsorption/desorption, the COD removal rate of the wastewater is greatly reduced, and the wastewater treatment effect is seriously reduced.

Comparative Example 4

The high-concentration organic wastewater containing organic/inorganic double salts in this example is the same as in Example 2.

The high-concentration organic/inorganic double salt-containing organic wastewater treatment device is the same as in Example 2.

The waste water is sent to the neutralization reaction separator with a pump, and 35% sodium hydroxide solution is added dropwise under stirring to adjust the pH to 7, and absorption or collection (absorption with water or ethanol, or condensed to below 6 °C to form a liquid collection) II The volatile dimethylamine gas generated by the decomposition of methylamine hydrochloride, the water phase is adsorbed in series with three-stage adsorption/desorption columns composed of three different adsorbents, wherein the first-stage adsorption/desorption column is equipped with macroporous resin ADS600 (120kg/ ^m3 wastewater), the secondary adsorption/desorption column is equipped with macroporous resin S-8 (80kg/ ^m3 wastewater), and the tertiary adsorption/desorption column is equipped with macroporous resin D3520 (40kg/ ^m3 waste water). The aqueous phase is introduced from the primary adsorption/desorption column and discharged from the tertiary adsorption/desorption column. After the three-stage adsorption/desorption column adsorption treatment, the COD of the adsorption liquid was reduced to 10120 mg/L, the ammonia nitrogen was reduced to 237 mg/L, and the adsorption liquid was a light yellow liquid. The COD removal rate of the adsorption liquid was 54%, and the ammonia nitrogen removal rate was 14.7%. High-quality inorganic salts cannot be recovered due to still high levels of organic impurities.

It can be seen from Comparative Example 4 that after the organic salts of the original wastewater are converted, the various levels of adsorbents used in the subsequent multi-stage adsorption/desorption columns are improperly selected or improperly combined, the COD removal rate is greatly reduced, and the wastewater treatment effect is seriously reduced.

Claims (8)

1. A method for treating high-concentration organic/inorganic double-salt-containing organic wastewater is characterized by comprising the following steps:

(1) conveying high-concentration organic/inorganic double-salt-containing organic wastewater to a neutralization reaction separator by using a pump, and adjusting the pH value of the wastewater by using acid or alkali; separating oil phase, solid phase or gas phase formed by decomposing the organic salt after pH adjustment from the water phase in a neutralization reaction separator;

(2) feeding the water phase led out in the step (1) into a multi-stage adsorption/desorption column, contacting and adsorbing with two or more different adsorbents, allowing the water phase to flow into the first-stage adsorption/desorption column, and discharging an adsorption solution from the last-stage adsorption/desorption column;

(3) recovering industrial inorganic salt from the adsorption solution obtained in the step (2), and returning the residual mother solution to a wastewater pool for circular treatment; desorbing the adsorbent which is adsorbed to be nearly saturated in the multistage adsorption/desorption column by using a desorbent to obtain desorption liquid, and regenerating the adsorbent for recycling in the step (2);

(4) and (4) sending the desorption liquid obtained in the step (3) into a desorption agent recovery tower, wherein the desorption agent recovery tower is a rectifying tower, the desorption agent is recovered from the top of the tower, the recovered desorption agent is circularly used in the step (3), and the organic waste liquid flowing out from the bottom of the tower is sent to an organic waste liquid tank and then sent to be further processed.

2. The method for treating high-concentration organic/inorganic double-salt-containing organic wastewater according to claim 1, wherein the high-concentration organic/inorganic double-salt-containing organic wastewater in the step (1) contains more than 2% of inorganic salt and organic salt by mass, more than 5% of total salt and more than 4000mg/mL of Chemical Oxygen Demand (COD).

3. The method for treating high-concentration organic/inorganic double-salt-containing organic wastewater according to claim 1, wherein the acid or base in the step (1) is a reagent capable of forming an inorganic salt with an inorganic acid group or an inorganic base of an organic salt in wastewater.

4. The method for treating high concentration organic/inorganic double salt-containing organic wastewater according to claim 1, wherein the multistage adsorption/desorption column of the step (2) is composed of 2 to 5 stages.

5. The method for treating high-concentration organic/inorganic double-salt-containing organic wastewater according to claim 4, wherein the adsorbent in the multistage adsorption/desorption column in the step (2) is selected from macroporous resin and modifications thereof, cross-linked or super-crosslinked resin, activated carbon, molecular sieve, silica gel, graphene and modifications thereof.

6. The method for treating high-concentration organic/inorganic double-salt-containing organic wastewater according to claim 1, wherein the inorganic salt recovery in the step (3) adopts membrane separation, ion exchange or evaporative crystallization, filtration and drying.

7. The method for treating high-concentration organic/inorganic double-salt-containing organic wastewater according to claim 1, wherein the desorbent in the step (4) is a low-carbon organic solvent or solution, and the dosage of the desorbent is 2-6 times of the volume of the adsorbent.

8. The method for treating high-concentration organic/inorganic double-salt-containing organic wastewater according to claim 1, wherein the organic waste liquid in the step (4) is subjected to recovery of refined organic substances, incineration treatment, or biochemical treatment of sewage, as the case may be.

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