CN116375244A - Treatment process of high-salt wastewater containing methylene dichloride - Google Patents
Treatment process of high-salt wastewater containing methylene dichloride Download PDFInfo
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- YMWUJEATGCHHMB-UHFFFAOYSA-N Dichloromethane Chemical compound ClCCl YMWUJEATGCHHMB-UHFFFAOYSA-N 0.000 title claims abstract description 144
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F9/00—Multistage treatment of water, waste water or sewage
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F11/00—Treatment of sludge; Devices therefor
- C02F11/12—Treatment of sludge; Devices therefor by de-watering, drying or thickening
- C02F11/121—Treatment of sludge; Devices therefor by de-watering, drying or thickening by mechanical de-watering
- C02F11/122—Treatment of sludge; Devices therefor by de-watering, drying or thickening by mechanical de-watering using filter presses
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/02—Treatment of water, waste water, or sewage by heating
- C02F1/04—Treatment of water, waste water, or sewage by heating by distillation or evaporation
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/20—Treatment of water, waste water, or sewage by degassing, i.e. liberation of dissolved gases
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
- C02F1/5236—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using inorganic agents
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
- C02F1/54—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using organic material
- C02F1/56—Macromolecular compounds
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F2001/007—Processes including a sedimentation step
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2101/00—Nature of the contaminant
- C02F2101/30—Organic compounds
- C02F2101/36—Organic compounds containing halogen
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F3/00—Biological treatment of water, waste water, or sewage
- C02F3/30—Aerobic and anaerobic processes
Abstract
The invention relates to the field of sewage treatment, and particularly discloses a high-salt wastewater treatment process containing methylene dichloride, which comprises the main processes of 'stripping + multi-effect evaporation + A/O biochemical treatment', wherein methylene dichloride in wastewater is separated and removed in advance through the stripping treatment, the influence of the methylene dichloride on subsequent biochemical treatment is avoided, the obtained methylene dichloride concentrated solution can be further used as a solvent, an extractant and other raw materials for recycling into production after purification, the multi-effect evaporation is used for carrying out evaporation concentration on the wastewater, the organic matter content and the salinity are reduced, the biodegradability of the wastewater is improved, the A/O process is adopted for carrying out biochemical treatment, the process parameters are optimized, the operation cost is reduced, the effluent quality is ensured to reach the emission requirement, and the effluent water after the A/O process treatment can reach the nanotube standard of a general chemical park.
Description
Technical Field
The invention relates to the technical field of wastewater treatment, in particular to a high-salt wastewater treatment process containing methylene dichloride.
Background
In fine chemical industry, biopharmaceutical industry and other industries, dichloromethane (DCM) is often used as an organic solvent, such as a solvent, an extractant, a mutagen and the like, and a production raw material. Dichloromethane is slightly soluble in water and has a boiling point of 39.8 ℃, and is listed as a list of toxic and harmful water pollutants due to high toxicity, residue and carcinogenicity. Methylene chloride in the production process is usually collected and treated in the form of waste gas, but the residual part in water still poses a threat to the environment and human health. In a biochemical system, wastewater containing methylene dichloride can have a strong inhibition effect on microorganisms in an activated sludge system, so that functional microorganisms such as COD degrading bacteria, nitrifying bacteria and denitrifying bacteria cannot play a normal role, the biochemical system is crashed, and the effluent quality cannot reach the discharge standard. For biochemical processes with poor salt tolerance, too high salt content can have obvious inhibition effect on biochemical effect. For high-salt wastewater, salt removal is generally performed by adopting an evaporation concentration mode, and the method has been widely used.
There is therefore a need for a process for treating high-salt wastewater containing methylene chloride which at least partially solves the problems of the prior art.
Disclosure of Invention
In the summary, a series of concepts in a simplified form are introduced, which will be further described in detail in the detailed description. The summary of the invention is not intended to define the key features and essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.
In order to at least partially solve the problems, the invention provides a process for treating high-salt wastewater containing methylene dichloride, which comprises the following treatment steps:
s100, blowing off: after the methylene dichloride-containing wastewater enters a collecting tank through a pipeline to be collected, the methylene dichloride-containing wastewater is pumped into a stripping tower through a pump to be subjected to stripping treatment, the temperature of liquid in the stripping tower is controlled to be 40-70 ℃, more preferably 50 ℃, and the stripping time is 30-120 min, more preferably 60min;
s200, multi-effect evaporation: the effluent of the stripping tower is conveyed into a triple-effect evaporator through a power pump for distillation treatment, and the fraction enters a biochemical regulating tank;
s300, water distribution: the low-concentration wastewater, the initial rainwater in the factory and the domestic sewage are introduced into a biochemical regulating tank and the effluent of the triple-effect evaporator for water distribution;
s400, A/O biochemical treatment: the water discharged from the biochemical regulating tank enters an A/O biochemical treatment process system, and flows into a collecting tank after the water quality reaches the discharge requirement.
Preferably, the step S400 specifically includes:
s401, anaerobic treatment: the effluent of the biochemical regulating tank enters a biochemical treatment process system, and firstly, the effluent of the biochemical regulating tank is introduced into an anaerobic tower for anaerobic biochemical treatment;
s402, aerobic treatment: introducing the effluent of the anaerobic tower into an aerobic tank, performing aerobic treatment through activated sludge, enabling the aerobic effluent to flow into a sedimentation tank for sludge-water separation, enabling the sludge to flow into a sludge concentration tank through a sludge pump, and enabling part of residual sludge to flow back into the anaerobic tower;
s403, concentrating sludge: the supernatant fluid and filter pressing effluent of the sludge concentration tank flow back to the biochemical regulating tank, the concentrated sludge enters a sludge filter press for filter pressing, and the dry sludge enters a solid waste incinerator for burning;
s404, flocculating settling: and (3) introducing the effluent of the sedimentation tank into a coagulating sedimentation tank, adding a flocculating agent to perform flocculating sedimentation, pumping the sediment sludge into a sludge concentration tank, and allowing the effluent to flow into a collecting tank.
Preferably, the stripping tower in the step S100 is a sieve plate tower, the dichloromethane wastewater enters a tower kettle from the top of the tower, and the water vapor is introduced from the bottom and fully exchanges heat with the wastewater.
Preferably, the gas discharged from the stripping tower in the step S100 is introduced into a condenser to be condensed, and the condensate is introduced into a receiving tank to be collected.
Preferably, the three-effect evaporator in the step S200 is used for controlling the distillation ratio to be more than or equal to 80 percent.
Preferably, sulfuric acid or liquid alkali is added into the biochemical regulating tank in the step S300 to control the pH value of the wastewater to be 7-8, and the water distribution ratio of the low-concentration wastewater, the initial rainwater in the factory area and the domestic sewage can be regulated according to actual production conditions.
Preferably, the anaerobic tower in the step S401 is inoculated with anaerobic activated sludge, the hydraulic retention time is controlled to be 12-16 h, the aerobic tank in the step S402 is inoculated with aerobic biological activated sludge, the hydraulic retention time of the aerobic tank is more than or equal to 36h, and the sludge reflux flows back to the front end of the anaerobic tower from the bottom of the sedimentation tank.
Preferably, the filter press in the step S403 is one of a plate-and-frame filter press and a belt filter press.
Preferably, the flocculant added in the step S404 is PAC (5%) and PAM (5%o), and the addition amounts of PAC and PAM are controlled to be between 0.5%o and 1%o.
Compared with the prior art, the high-salt wastewater treatment process containing methylene dichloride provided by the invention at least comprises the following beneficial effects:
(1) Firstly, carrying out stripping treatment on the wastewater and controlling the proper temperature, so that most of the dissolved dichloromethane in the wastewater is collected and removed in a gas form, and the dichloromethane is preferentially removed, so that the condition that the dichloromethane cannot be thoroughly removed due to the fact that the dichloromethane is mixed into condensate in evaporation desalting is avoided, and the biodegradability of the wastewater is improved;
(2) The methylene dichloride concentrated solution can be obtained after stripping and condensation, and the methylene dichloride solution can be further used as raw materials such as solvent, extractant and the like for recycling in production after purification, so that the cost of the raw materials is reduced, and the recycling is realized;
(3) The salt in the wastewater is separated through the triple-effect evaporator, and meanwhile, the high-boiling-point refractory organic matters of macromolecules are separated into concentrated solution, so that the biodegradability of the wastewater is improved while the content of the organic matters is reduced, and the subsequent biochemical treatment process is facilitated;
(4) The wastewater after physical and chemical treatment is biologically treated by adopting the A/O technology, the technological parameters are optimized, the running cost is reduced, the effluent quality is ensured to reach the emission requirement, and the wastewater after being treated by the A/O technology can reach the nano tube standard of a general chemical industry park.
Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention.
Drawings
The accompanying drawings are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate the invention and together with the embodiments of the invention, serve to explain the invention. In the drawings:
FIG. 1 is a schematic diagram of a process for treating high salt wastewater containing methylene chloride according to the present invention.
Detailed Description
The present invention is described in further detail below with reference to the drawings and examples to enable those skilled in the art to practice the invention by referring to the description.
It will be understood that terms, such as "having," "including," and "comprising," as used herein, do not preclude the presence or addition of one or more other elements or groups thereof.
As shown in fig. 1, the invention provides a treatment process of high-salt wastewater containing methylene dichloride, which comprises the following treatment steps:
s100, blowing off: after the methylene dichloride-containing wastewater enters a collecting tank through a pipeline to be collected, the methylene dichloride-containing wastewater is pumped into a stripping tower through a pump to be subjected to stripping treatment, the temperature of liquid in the stripping tower is controlled to be 40-70 ℃, more preferably 50 ℃, and the stripping time is 30-120 min, more preferably 60min;
s200, multi-effect evaporation: the effluent of the stripping tower is conveyed into a triple-effect evaporator through a power pump for distillation treatment, and the fraction enters a biochemical regulating tank;
s300, water distribution: the low-concentration wastewater, the initial rainwater in the factory and the domestic sewage are introduced into a biochemical regulating tank and the effluent of the triple-effect evaporator for water distribution;
s400, A/O biochemical treatment: the water discharged from the biochemical regulating tank enters an A/O biochemical treatment process system, and flows into a collecting tank after the water quality reaches the discharge requirement.
The step S400 specifically includes:
s401, anaerobic treatment: the effluent of the biochemical regulating tank enters a biochemical treatment process system, and firstly, the effluent of the biochemical regulating tank is introduced into an anaerobic tower for anaerobic biochemical treatment;
s402, aerobic treatment: introducing the effluent of the anaerobic tower into an aerobic tank, performing aerobic treatment through activated sludge, enabling the aerobic effluent to flow into a sedimentation tank for sludge-water separation, enabling the sludge to flow into a sludge concentration tank through a sludge pump, and enabling part of residual sludge to flow back into the anaerobic tower;
s403, concentrating sludge: the supernatant fluid and filter pressing effluent of the sludge concentration tank flow back to the biochemical regulating tank, the concentrated sludge enters a sludge filter press for filter pressing, and the dry sludge enters a solid waste incinerator for burning;
s404, flocculating settling: and (3) introducing the effluent of the sedimentation tank into a coagulating sedimentation tank, adding a flocculating agent to perform flocculating sedimentation, pumping the sediment sludge into a sludge concentration tank, and allowing the effluent to flow into a collecting tank.
The stripping tower in the step S100 is set as a sieve plate tower, the dichloromethane wastewater enters a tower kettle from the top of the tower, and the water vapor is introduced from the bottom and fully exchanges heat with the wastewater.
And (3) introducing the exhaust gas discharged by the stripping tower in the step (S100) into a condenser for condensation, and introducing the condensate into a receiving tank for collection.
The three-effect evaporator in the step S200 is controlled to have the distillate ratio of more than or equal to 80 percent.
And the biochemical regulating tank in the step S300 is added with sulfuric acid or liquid alkali to control the pH value of the wastewater to be 7-8, and the water distribution ratio of the low-concentration wastewater, the initial rainwater in the factory area and the domestic sewage can be regulated according to actual production conditions.
The anaerobic tower in the step S401 is inoculated with anaerobic activated sludge, the hydraulic retention time is controlled to be 12-16 h, the aerobic tank in the step S402 is inoculated with aerobic biological activated sludge, the hydraulic retention time of the aerobic tank is more than or equal to 36h, and the sludge reflux flows back to the front end of the anaerobic tower from the bottom of the sedimentation tank.
The filter press in step S403 is one of a plate-and-frame filter press and a belt filter press.
The flocculant added in the step S404 is PAC (5%) and PAM (5%o), and the addition amounts of the PAC and the PAM are controlled between 0.5%o and 1%o.
Example 1 high salt wastewater containing methylene chloride was treated by the following steps:
(1) Blowing off: collecting high-salt wastewater containing methylene dichloride through a pipeline, introducing the wastewater into a stripping tower through a power pump for stripping treatment, introducing waste gas in the stripping tower into a condenser for condensation, controlling the temperature of wastewater in the tower to 40 ℃, enabling the stripping time to be 60min, steaming out low-boiling methylene dichloride from a water phase under the heating of water vapor, condensing the steamed methylene dichloride gas in the condenser, collecting condensate by a receiving tank, purifying the condensed methylene dichloride solution, and recycling the purified methylene dichloride solution into production; wherein the dichloromethane content of the high-salt wastewater containing dichloromethane is 4450mg/L, the salt content is 16760mg/L, and the pH value is 9.68;
(2) Multiple effect evaporation: the effluent of the stripping tower is conveyed into a triple-effect evaporator through a power pump for distillation treatment, the distillation ratio of the triple-effect evaporator is controlled to be 80%, substances with low boiling point (boiling point is less than or equal to 100 ℃) in the wastewater are converted into gas under the condition of high temperature and are distilled after condensation, substances such as salt and high boiling point organic matters are left in concentrated solution, the concentrated solution is treated as dangerous waste after being discharged periodically, and the fractions enter a biochemical regulating tank;
(3) And (3) water distribution: the factory area comprises, but is not limited to, low-concentration wastewater, factory area initial rainwater and domestic sewage, and is introduced into a biochemical regulating tank, water distribution is carried out on the effluent of the triple-effect evaporator, the low-concentration water is reasonably utilized, the pollutant concentration of biochemical inflow water is reduced, and a proper amount of sulfuric acid is added to regulate the pH value to 7, so that the water distribution proportion of the low-concentration wastewater, the factory area initial rainwater and the domestic sewage can be regulated according to actual production conditions;
(4) Anaerobic treatment: the effluent of the biochemical regulating tank enters a biochemical treatment process system, and firstly, the effluent of the biochemical regulating tank is introduced into an anaerobic tower for anaerobic biochemical treatment; anaerobic towers are inoculated with anaerobic activated sludge, the hydraulic retention time is controlled to be 16 hours, and anaerobic microorganisms can remove and convert macromolecular organic matters in the wastewater into micromolecular organic matters when growing by taking organic matters in the wastewater as a carbon source, so that the biodegradability of the wastewater is improved, and the subsequent biochemical treatment is facilitated;
(5) And (3) aerobic treatment: introducing the effluent of the anaerobic tower into an aerobic tank, performing aerobic treatment through activated sludge and aeration, enabling the aerobic effluent to flow into a sedimentation tank for sludge-water separation, enabling the sludge to flow into a sludge concentration tank through a sludge pump, and enabling part of residual sludge to flow back into the anaerobic tower; the aerobic tank is inoculated with aerobic biological activated sludge, the hydraulic retention time of the aerobic tank is 36h, the sludge concentration is 4000-5000 mg/L, functional bacteria such as COD degrading bacteria and nitrifying bacteria in the aerobic tank can further remove organic matters and ammonia nitrogen in wastewater, and as substances such as dichloromethane and macromolecular refractory organic matters are removed from the front end, the pollutant removing effect of the aerobic microorganisms can be fully exerted;
(6) And (3) concentrating sludge: the supernatant fluid of the sludge concentration tank and filter pressing effluent flow back to the biochemical regulating tank, concentrated sludge enters a sludge filter press for filter pressing, the filter press is a plate-and-frame filter press, filtrate of the filter press and the supernatant fluid of the sludge concentration tank flow back to the biochemical regulating tank, and dry sludge enters a solid waste incinerator for incineration;
(7) Flocculation precipitation: introducing the effluent of the sedimentation tank into a coagulating sedimentation tank, adding a flocculating agent to perform flocculating sedimentation, pumping the sediment sludge into a sludge concentration tank, and allowing the effluent to flow into a collecting tank; the flocculant is PAC (5%) and PAM (5%o), and the dosage of PAC and PAM is controlled to be 1%o; after flocculation and precipitation, SS in the effluent of the sedimentation tank is further removed, and the effluent is ensured to be discharged up to the standard.
Through the treatment, under the water quality conditions that the dichloromethane content of the wastewater is 4450mg/L, the salinity is 16760mg/L and the COD content is 30784mg/L, the COD can be reduced to below 350mg/L, the salinity is reduced to below 500mg/L, the dichloromethane can be basically removed, and the specific removal effect is shown in Table 1.
TABLE 1
In the stripping process, the stripping reaction time has a significant effect on the removal of methylene dichloride and also has a certain effect on the removal of COD, and the specific conditions are shown in Table 2.
TABLE 2
| Reaction time (min) | COD(mg/L) | Dichloromethane (mg/L) |
| 0 | 30784 | 4450 |
| 15 | 27782 | 652 |
| 30 | 27042 | 610 |
| 45 | 26584 | 9.23 |
| 60 | 26087 | 1.37 |
Therefore, in the stripping process, in order to ensure the removal effect of the dichloromethane and improve the biodegradability of the wastewater, the stripping reaction time should be at least 45min when the concentration of the dichloromethane is more than 4450 mg/L.
Comparative example 1
After the high-salt wastewater containing methylene chloride was subjected to the same stripping and evaporation concentration treatment as in example 1, the wastewater was further treated by using the Fenton technique.
The Fenton treatment process comprises the following steps: adding sulfuric acid to the concentrated water to adjust pH=2.6, and controlling n (H 2 O 2 )：n(Fe 2+ ) Respectively adding ferrous sulfate heptahydrate into the mixture, stirring the mixture, fully mixing the mixture and dissolving the mixture, and respectively adding 0.5%, 1% and 2% of H into the mixture 2 O 2 Solution, hrt=3 h. The Fenton process needs to use ferrous sulfate, hydrogen peroxide, sulfuric acid and other medicaments, and more iron-containing sludge can be generated in the Fenton process, so that the sludge treatment cost is higher, and the operation cost is greater than that of an A/O biochemical process. The Fenton treatment specific effect of the evaporated and concentrated effluent is shown in Table 3.
TABLE 3 Table 3
| Treatment of | COD(mg/L) | Ammonia nitrogen (mg/L) | TP(mg/L) |
| Raw water | 1563 | 95.0 | 0.35 |
| 0.5％H 2 O 2 | 873 | 42.9 | 0.32 |
| 1％H 2 O 2 | 784 | 42.0 | 0.29 |
| 2％H 2 O 2 | 556 | 34.5 | 0.24 |
In the comparative example 1, the Fenton treatment has no improvement on the removal effect of the wastewater on the premise of increasing the treatment cost, and the removal effect is obviously inferior to that of the A/O biochemical process, so that the A/O process is adopted after the evaporation concentration treatment, the removal effect can be improved, the treatment cost can be reduced, and the management and the maintenance are convenient.
While embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations may be made therein without departing from the spirit and scope of the invention as defined by the appended claims and their equivalents, and therefore the invention is not to be limited to the specific details and illustrations shown and described herein without departing from the general concept as defined by the appended claims and their equivalents.
Claims (9)
1. The high-salt wastewater treatment process containing methylene dichloride is characterized by comprising the following treatment steps of:
s100, blowing off: after the methylene dichloride-containing wastewater enters a collecting tank through a pipeline to be collected, the methylene dichloride-containing wastewater is pumped into a stripping tower through a pump to be subjected to stripping treatment, the temperature of liquid in the stripping tower is controlled to be 40-70 ℃, and the stripping time is controlled to be 60min;
s200, multi-effect evaporation: the effluent of the stripping tower is conveyed into a triple-effect evaporator through a power pump for distillation treatment, and the fraction enters a biochemical regulating tank;
s300, water distribution: the low-concentration wastewater, the initial rainwater in the factory and the domestic sewage are introduced into a biochemical regulating tank and the effluent of the triple-effect evaporator for water distribution;
s400, A/O biochemical treatment: the water discharged from the biochemical regulating tank enters an A/O biochemical treatment process system, and flows into a collecting tank after the water quality reaches the discharge requirement.
2. The process for treating high-salt wastewater containing methylene chloride according to claim 1, wherein said step S400 comprises:
s401, anaerobic treatment: the effluent of the biochemical regulating tank enters a biochemical treatment process system, and firstly, the effluent of the biochemical regulating tank is introduced into an anaerobic tower for anaerobic biochemical treatment;
s402, aerobic treatment: introducing the effluent of the anaerobic tower into an aerobic tank, performing aerobic treatment through activated sludge, enabling the aerobic effluent to flow into a sedimentation tank for sludge-water separation, enabling the sludge to flow into a sludge concentration tank through a sludge pump, and enabling part of residual sludge to flow back into the anaerobic tower;
s403, concentrating sludge: the supernatant fluid and filter pressing effluent of the sludge concentration tank flow back to the biochemical regulating tank, the concentrated sludge enters a sludge filter press for filter pressing, and the dry sludge enters a solid waste incinerator for burning;
s404, flocculating settling: and (3) introducing the effluent of the sedimentation tank into a coagulating sedimentation tank, adding a flocculating agent to perform flocculating sedimentation, pumping the sediment sludge into a sludge concentration tank, and allowing the effluent to flow into a collecting tank.
3. The process for treating high-salt wastewater containing methylene chloride according to claim 2, wherein the stripping tower in the step S100 is a sieve plate tower, the methylene chloride wastewater enters a tower kettle from the top of the tower, and water vapor is introduced from the bottom and fully exchanges heat with the wastewater.
4. The process for treating high-salt wastewater containing methylene chloride according to claim 1, wherein the gas discharged from the stripping tower in the step S100 is introduced into a condenser for condensation, and the condensate is introduced into a receiving tank for collection.
5. The process for treating high-salt wastewater containing methylene chloride according to claim 1, wherein the three-effect evaporator in the step S200 is controlled to have a distillate ratio of 80% or more.
6. The process for treating high-salt wastewater containing dichloromethane according to claim 1, wherein sulfuric acid or liquid alkali is added into the biochemical regulating tank in the step S300 to control the pH of the wastewater to 7-8, and the water distribution ratio of the low-concentration wastewater, the initial rainwater in the factory and the domestic sewage can be regulated according to actual production conditions.
7. The process for treating high-salt wastewater containing methylene dichloride according to claim 2, wherein the anaerobic tower in the step S401 is inoculated with anaerobic activated sludge, the hydraulic retention time is controlled to be 12-16 h, the aerobic tank in the step S402 is inoculated with aerobic biological activated sludge, the hydraulic retention time of the aerobic tank is more than or equal to 36h, and the sludge reflux flows back to the front end of the anaerobic tower from the bottom of the sedimentation tank.
8. The process for treating high-salt wastewater containing methylene chloride according to claim 2, wherein the filter press in the step S403 is one of a plate-and-frame filter press and a belt filter press.
9. The process for treating high-salt wastewater containing dichloromethane according to claim 2, wherein the flocculant added in the step S404 is PAC (5%) and PAM (5%o), and the dosage of PAC and PAM is controlled to be between 0.5%o and 1%o.
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