CN113072228A - Method and system for treating salt-containing wastewater - Google Patents

Method and system for treating salt-containing wastewater Download PDF

Info

Publication number
CN113072228A
CN113072228A CN202010006094.9A CN202010006094A CN113072228A CN 113072228 A CN113072228 A CN 113072228A CN 202010006094 A CN202010006094 A CN 202010006094A CN 113072228 A CN113072228 A CN 113072228A
Authority
CN
China
Prior art keywords
unit
salt
concentration
pretreatment
nanofiltration
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN202010006094.9A
Other languages
Chinese (zh)
Inventor
张旭
张海珠
蔡维婷
薛旭
厉阳
杨照
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
China Petroleum and Chemical Corp
Sinopec Engineering Inc
Original Assignee
China Petroleum and Chemical Corp
Sinopec Engineering Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by China Petroleum and Chemical Corp, Sinopec Engineering Inc filed Critical China Petroleum and Chemical Corp
Priority to CN202010006094.9A priority Critical patent/CN113072228A/en
Publication of CN113072228A publication Critical patent/CN113072228A/en
Pending legal-status Critical Current

Links

Images

Classifications

    • 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
    • C01—INORGANIC CHEMISTRY
    • C01D—COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
    • C01D3/00—Halides of sodium, potassium or alkali metals in general
    • C01D3/04—Chlorides
    • C01D3/06—Preparation by working up brines; seawater or spent lyes
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01D—COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
    • C01D3/00—Halides of sodium, potassium or alkali metals in general
    • C01D3/14—Purification
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01D—COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
    • C01D5/00—Sulfates or sulfites of sodium, potassium or alkali metals in general
    • C01D5/16—Purification
    • 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
    • C02F1/001—Processes for the treatment of water whereby the filtration technique is of importance
    • 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
    • C02F1/048—Purification of waste water by 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
    • C02F1/02—Treatment of water, waste water, or sewage by heating
    • C02F1/04—Treatment of water, waste water, or sewage by heating by distillation or evaporation
    • C02F1/08—Thin film 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
    • C02F1/42—Treatment of water, waste water, or sewage by ion-exchange
    • 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
    • C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
    • C02F1/441—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by reverse osmosis
    • 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
    • C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
    • C02F1/442—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by nanofiltration
    • 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
    • C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
    • C02F1/444—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by ultrafiltration or microfiltration
    • 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
    • C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
    • C02F1/445—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by forward osmosis
    • 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
    • C02F1/46—Treatment of water, waste water, or sewage by electrochemical methods
    • C02F1/469—Treatment of water, waste water, or sewage by electrochemical methods by electrochemical separation, e.g. by electro-osmosis, electrodialysis, electrophoresis
    • C02F1/4693—Treatment of water, waste water, or sewage by electrochemical methods by electrochemical separation, e.g. by electro-osmosis, electrodialysis, electrophoresis electrodialysis
    • 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
    • C02F1/72—Treatment of water, waste water, or sewage by oxidation
    • 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
    • C02F1/72—Treatment of water, waste water, or sewage by oxidation
    • C02F1/78—Treatment of water, waste water, or sewage by oxidation with ozone
    • 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
    • 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
    • C02F2101/10—Inorganic compounds
    • C02F2101/101—Sulfur compounds
    • 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
    • C02F2101/10—Inorganic compounds
    • C02F2101/12—Halogens or halogen-containing compounds
    • 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
    • C02F2101/10—Inorganic compounds
    • C02F2101/16—Nitrogen compounds, e.g. ammonia
    • 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
    • C02F2101/10—Inorganic compounds
    • C02F2101/20—Heavy metals or heavy metal compounds
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
    • C02F2103/34—Nature of the water, waste water, sewage or sludge to be treated from industrial activities not provided for in groups C02F2103/12 - C02F2103/32
    • 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
    • C02F3/02—Aerobic processes
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F5/00—Softening water; Preventing scale; Adding scale preventatives or scale removers to water, e.g. adding sequestering agents

Abstract

The system comprises a salt-containing wastewater raw water tank, a first pretreatment unit, a second pretreatment unit, a reuse water tank, a nanofiltration treatment unit, a sodium sulfate crystallization unit, a concentration unit, a sodium chloride crystallization unit and a miscellaneous salt treatment unit. By adopting the method and the system, sodium sulfate crystal salt, sodium chloride crystal salt and reuse water meeting the industrial standard can be obtained without additional secondary treatment or simple treatment, so that near zero emission of salt-containing wastewater is realized, and ideal economic benefits are achieved.

Description

Method and system for treating salt-containing wastewater
Technical Field
The disclosure relates to the technical field of salt-containing wastewater treatment, in particular to a method and a system for treating salt-containing wastewater, and particularly relates to a method and a system for treating high-salinity wastewater.
Background
The salt-containing wastewater mainly comes from the production process of petrochemical and coal chemical enterprises, and the wastewater contains various substances (including salt, oil, organic heavy metal and radioactive substances), has complex composition and NH3high-N value, high salt content, high heavy metal content, high toxicity, high hardness, large water quantity, large fluctuation range of water quality, large treatment difficulty and the like. Generally, the salt-containing wastewater obtained in this way has a total salt content of not less than 1% and is called high-salinity wastewater, and the TDS (total dissolved salt content) of the high-salinity wastewater is in the range of several tens of thousands to several hundreds of thousands ppm, wherein the dissolved salts are mainly two salts of sodium sulfate and sodium chloride. The salinity of the salt-containing wastewater generally comes from circulating water pollution discharge, chemical water station drainage, salt-containing sewage after biochemical treatment and the like; in the coal chemical industry, besides a large amount of saline wastewater generated by coal gasification, a certain amount of acid and alkali are added in the wastewater treatment process, and finally exist in high-salt water in the form of sulfate and chloride.
With the rapid development of the economic society, the chemical industry is also developed vigorously, and a large amount of salt-containing wastewater is generated in the production process, so that serious environmental and resource problems are derived. Therefore, the development and design of a saline wastewater treatment scheme with long-period operation, good treatment effect, low investment and operation cost and small floor area are urgently needed in the field.
CN 105540980A discloses a high-salt-content industrial wastewater advanced oxidation-salt separation crystallization combined system, and the system and the process are characterized in that pretreated high-salt water enters an ozone advanced oxidation device, and the advanced oxidation treatment by means of ozone is combined with MVR evaporation crystallization and freezing crystallization technologies, so that the COD concentration of the treated effluent is less than 50mg/L, and the process needs to prepare ozone by means of an ozone generator, and the cost is high.
CN 105197965a discloses a method for extracting mirabilite and industrial salt from high-salt wastewater. The method mainly comprises the steps of carrying out advanced oxidation, deep softening, membrane concentration, freezing denitration, deep denitration and the like on high-salinity water to extract mirabilite and industrial salt in the wastewater, wherein the advanced oxidation step is to utilize concentrated H2SO4The treatment generates a large amount of acid-containing waste liquid, and the equipment is seriously corroded.
CN 105417817a discloses a high-salinity wastewater treatment system and method. The method mixes the crystal into the fly ash and removes the crystal together by arranging an atomizer and a boiling point reducing device, and the obtained mixed salt still contains substances such as heavy metals, organic matters, inorganic matters and the like.
CN 105254106A discloses a treatment method and a device for zero discharge and salt separation of high-salinity wastewater, the method firstly carries out pretreatment on the wastewater through a chemical softening-tubular microfiltration treatment process, then carries out decrement concentration through a nanofiltration-reverse osmosis-disc tubular reverse osmosis decrement concentration process, and finally obtains treated water through crystallization. The tubular microfiltration membrane is easy to be polluted and blocked and has large pressure drop; the disc tube type reverse osmosis has small operation elasticity, poor anti-fouling capability, higher equipment cost and high requirement on the quality of the treated high-salt water. The method and the device have the advantages of high energy consumption, unstable quality of reuse water and short operation period; the obtained mixed salt still contains partial impurities such as heavy metals, organic matters and the like, secondary treatment is needed, the process steps are complex, and the time for treating unit wastewater is long.
In summary, in the prior art, near zero discharge of salt-containing wastewater is often limited to zero discharge of liquid or local devices, and recycling of salt-containing wastewater is often limited to recycling of salt or recycled water, which causes a great waste of resources and is not in accordance with the current sustainable development concept. Most of the by-product salt is crystallized and precipitated in a mixed salt mode, the obtained mixed salt contains heavy metals, organic matters, inorganic matters and other substances, most areas are defined as hazardous wastes at the present stage, the waste cannot be recycled, a professional hazardous waste manufacturer is required for treatment, the secondary treatment increases the treatment cost, and the problem of environmental pollution is also caused. Therefore, it is urgently needed to develop a treatment process of salt-containing wastewater, so that main components such as sodium sulfate, sodium chloride and the like in the salt-containing wastewater are recovered while the wastewater is treated, and the targets of 'zero emission' and 'resource' are really realized.
Disclosure of Invention
The purpose of the disclosure is to provide a method and a system for treating salt-containing wastewater, wherein the method can simultaneously recover and obtain crystallized salt and reuse water meeting industrial standards, does not need secondary treatment, and saves energy consumption.
In order to achieve the above object, a first aspect of the present disclosure provides a method for treating salt-containing wastewater, comprising the steps of:
s1, carrying out first pretreatment on the salt-containing wastewater to obtain a first pretreatment solution and a first recovery solution;
s2, carrying out second pretreatment on the first pretreatment solution to obtain a second pretreatment solution and a second recovery solution;
s3, performing nanofiltration separation treatment on the second pretreatment solution to obtain nanofiltration concentrated water and nanofiltration produced water;
s4, carrying out sodium sulfate crystallization treatment on the nanofiltration concentrated water to obtain sodium sulfate crystalline salt, a third recovery liquid and a first discharged mother liquid;
s5, concentrating the nanofiltration water and crystallizing sodium chloride to obtain sodium chloride crystallized salt, a fourth recovery liquid and a second external mother liquid;
s6, mixing the first discharged mother liquor and the second discharged mother liquor, and then carrying out mixed salt treatment to obtain mixed salt and final mother liquor;
and S7, mixing the first recovery liquid, the second recovery liquid, the third recovery liquid and the fourth recovery liquid to obtain reuse water, wherein the TDS content of the reuse water is 0-1000mg/L, and the COD is 0-50 mg/L.
Optionally, the method further comprises: before step S1, boosting the pressure of the salt-containing wastewater, wherein the pressure of the boosted salt-containing wastewater is 0.3-1.5 MPa; and/or the like and/or,
before step S3, the pressure of the second pretreatment liquid is increased, and the pressure of the second pretreatment liquid after the pressure increase is 1.0 to 4.5 MPa.
Optionally, in step S5, the concentration process includes a reverse osmosis concentration process.
Optionally, the pH value of the salt-containing wastewater is 6-11, the TDS content is 2000-45000mg/L, and SO4 2-The concentration is 1000-25000mg/L, Cl-The concentration is 500-10000mg/L, the COD is 200-2500mg/L, the total hardness is 0-500mg/L, SiO2Concentration of 0-100mg/L, CO3 2-The concentration is 0-100 mg/L.
Optionally, in step S1, the first pretreatment comprises at least one of solid-liquid separation, oxidation, ion exchange and filtration steps, and the pH value of the obtained first pretreatment solution is 6-10, the TDS content is 3500-45000mg/L, and the SO content is4 2-Concentration of 1000-30000mg/L, Cl-The concentration is 500-12000mg/L, the COD is 30-2000mg/L, the total hardness is 0-450mg/L, SiO2Concentration of 0-80mg/L, CO3 2-The concentration is 0-50 mg/L; and/or the like and/or,
in step S2, the second pretreatment step includes at least one of softening, oxidizing, decarbonizing and filtering steps, the pH value of the obtained second pretreatment solution is 5-9, the TDS content is 4000-4 2-The concentration is 1500--The concentration is 800-25000mg/L, the COD is 20-300mg/L, the total hardness is 0-20mg/L, SiO2Concentration of 0-30mg/L, CO3 2-The concentration is 0-5 mg/L.
Optionally, the method further comprises: step S8, drying the sodium sulfate crystalline salt, the sodium chloride crystalline salt and the miscellaneous salt respectively, and carrying out centrifugal drying treatment on the final mother liquor; alternatively, the first and second electrodes may be,
and respectively drying the sodium sulfate crystal salt and the sodium chloride crystal salt, and drying the mixed salt and the final mother liquor.
The second aspect of the present disclosure provides a system for treating salt-containing wastewater, which includes a salt-containing wastewater raw water tank, a first pretreatment unit, a second pretreatment unit, a reuse water tank, a nanofiltration treatment unit, a sodium sulfate crystallization unit, a concentration unit, a sodium chloride crystallization unit and a miscellaneous salt treatment unit;
the outlet of the saline wastewater raw water tank is communicated with the inlet of the first pretreatment unit, the pretreatment liquid outlet of the first pretreatment unit is communicated with the inlet of the second pretreatment unit, the pretreatment liquid outlet of the second pretreatment unit is communicated with the inlet of the nanofiltration treatment unit, the nanofiltration treatment unit comprises a nanofiltration concentrated water outlet and a nanofiltration water outlet, the nanofiltration concentrated water outlet is communicated with the inlet of the sodium sulfate crystallization unit, an outlet of the discharged mother liquor of the sodium sulfate crystallization unit is communicated with an inlet of the mixed salt treatment unit, the nanofiltration water outlet is communicated with the inlet of the concentration unit, the concentrated water outlet of the concentration unit is communicated with the inlet of the sodium chloride crystallization unit, an outlet of the mother liquor discharged from the sodium chloride crystallization unit is communicated with an inlet of the miscellaneous salt treatment unit,
and the inlet of the reuse water tank is respectively communicated with the recovered liquid outlet of the first pretreatment unit, the recovered liquid outlet of the second pretreatment unit, the recovered liquid outlet of the sodium sulfate crystallization unit, the recovered liquid outlet of the concentration unit and the recovered liquid outlet of the sodium chloride crystallization unit.
Optionally, the first pretreatment unit comprises one or more of a homogenization adjusting tank, a high-density clarification tank, an ozone catalytic oxidation device, a biological aerated filter, a sand filter, an immersed ultrafiltration device, an ion exchange device and a reverse osmosis device; and/or the like and/or,
the second pretreatment unit comprises one or more of a raw material concentrated water tank, a silicon and hardness removing device, an advanced oxidation/COD removing device, a decarburization device and an ultrafiltration device.
Optionally, the nanofiltration treatment unit comprises a nanofiltration membrane device, and the number of the nanofiltration membrane device is 1-5, preferably 2-3.
Optionally, the sodium sulfate crystallization unit comprises one or more of a freezing crystallization device, a multi-effect vacuum evaporation crystallization device, an MVR evaporation crystallization device and a falling film evaporation crystallization device, and preferably the multi-effect vacuum evaporation crystallization device and/or the MVR evaporation crystallization device; and/or the like and/or,
the concentration unit comprises at least one of a reverse osmosis device, an electrodialysis device and a forward osmosis device, and is preferably a reverse osmosis device; and/or the like and/or,
the sodium chloride crystallization unit comprises one or more of a multi-effect vacuum evaporation crystallization device, an MVR evaporation crystallization device and a falling film evaporation crystallization device, and preferably comprises the multi-effect vacuum evaporation crystallization device and/or the MVR evaporation crystallization device; and/or the like and/or,
the mixed salt treatment unit comprises one or more of a multi-effect vacuum evaporation crystallization device, an MVR evaporation crystallization device and a falling film evaporation crystallization device, and preferably comprises the multi-effect vacuum evaporation crystallization device and/or the MVR evaporation crystallization device.
Through the technical scheme, compared with the prior art, the method and the system disclosed by the invention have the following advantages:
1. by adopting the method and the system, extra steps are not needed, the sodium sulfate crystalline salt meeting the first-class standard of I-type salt in the GB/T6009-2014 industrial anhydrous sodium sulfate standard and the sodium chloride crystalline salt meeting the first-class standard of refined industrial dry salt in the GB/T5462-industrial salt standard can be directly recovered, and the recovered reuse water can be used for obtaining the recovered water quality meeting the reclaimed water quality standard HG-T3923-2007 for circulating cooling water without secondary treatment or simple treatment.
2. The method and the system disclosed by the invention can effectively remove COD (chemical oxygen demand), hardness, heavy metal ions and SiO (silicon dioxide) in the wastewater by arranging the two-stage pretreatment unit2、CO3 2-The impurities such as ions and the like reduce the pollution and blockage problem in the subsequent process, then the nanofiltration concentrated water with high-concentration sodium sulfate and the nanofiltration produced water with high-concentration sodium chloride are separated by using the nanofiltration unit, and corresponding concentration and crystallization treatment steps are selected according to respective characteristics, so that the overall device scale of the system is reduced, the cost is reduced, and the ideal economic benefit is achieved.
3. The method and the system can treat large-volume salt-containing wastewater, are suitable for salt-containing wastewater with different salt-containing mass fractions and different water qualities, and have wide application range and stable operation of the device.
Additional features and advantages of the disclosure will be set forth in the detailed description which follows.
Drawings
The accompanying drawings, which are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure and together with the description serve to explain the disclosure without limiting the disclosure. In the drawings:
FIG. 1 is a schematic view of one embodiment of a system for treating wastewater containing salt according to the present invention;
FIG. 2 is a schematic view of a first pretreatment unit of one embodiment of the system for treating wastewater containing salt of the present invention;
FIG. 3 is a schematic view of a second pretreatment unit of an embodiment of the system for treating wastewater containing salt according to the present invention.
Description of the reference numerals
101-a salt-containing wastewater raw water tank; 102-a first pre-processing unit; 103-a second pre-processing unit; 104-a reuse water pool; 201-a nanofiltration treatment unit; 301-sodium sulfate crystallization unit; 302-a concentration unit; 303-sodium chloride crystallization unit; 401-miscellaneous salt treatment unit; 501-a packaging unit;
1021-homogenizing adjusting tank; 1022-high density clarifier; 1023-an oxidation unit; 1024-sand filter; 1025-submerged ultrafiltration device; 1026 — an ion exchange device; 1027-reverse osmosis unit;
1031-a silicon and hardness removing device; 1032-advanced oxidation/COD removal unit; 1033-a decarbonization column; 1034-ultrafiltration device.
Detailed Description
The following detailed description of specific embodiments of the present disclosure is provided in connection with the accompanying drawings. It should be understood that the detailed description and specific examples, while indicating the present disclosure, are given by way of illustration and explanation only, and are not intended to limit the present disclosure.
The present disclosure provides in a first aspect a method for treating salt-containing wastewater, which may include the steps of:
s1, carrying out first pretreatment on the salt-containing wastewater to obtain a first pretreatment solution and a first recovery solution;
s2, carrying out second pretreatment on the first pretreatment solution to obtain a second pretreatment solution and a second recovery solution;
s3, performing nanofiltration separation treatment on the second pretreatment solution to obtain nanofiltration concentrated water and nanofiltration produced water;
s4, carrying out sodium sulfate crystallization treatment on the nanofiltration concentrated water to obtain sodium sulfate crystalline salt, a third recovery liquid and a first discharged mother liquid;
s5, concentrating the nanofiltration water and crystallizing sodium chloride to obtain sodium chloride crystallized salt, a fourth recovery liquid and a second external mother liquid;
s6, mixing the first discharged mother liquor and the second discharged mother liquor, and then carrying out mixed salt treatment to obtain mixed salt and final mother liquor;
and S7, mixing the first recovery solution, the second recovery solution, the third recovery solution and the fourth recovery solution to obtain reuse water, wherein the TDS content of the reuse water is 0-1000mg/L, preferably 10-300mg/L, and the COD is 0-50mg/L, preferably 5-30 mg/L.
The inventor of the present disclosure finds that COD, hardness, heavy metal ions and SiO in wastewater can be effectively removed by skillfully arranging two stages of pretreatment units in advance2、CO3 2-Ion and other impurities to obtain the pretreatment of target water qualityThe liquid and the recovery liquid which is produced in the process and meets the standard are recovered to a recovery water tank, so that the pollution and blockage problems in the subsequent process can be reduced, the load and the energy consumption in the subsequent process can be obviously reduced, then nanofiltration concentrated water with high-concentration sodium sulfate and nanofiltration produced water with high-concentration sodium chloride are separated by utilizing the arrangement of a nanofiltration unit, and corresponding concentration crystallization treatment is selected according to respective characteristics, so that the scale of the total device of the system is reduced, the total energy consumption is obviously reduced, and the recovery rate of the sodium sulfate, the sodium chloride and the water in the salt-containing wastewater is improved by more than 30 percent compared with the prior art.
According to the present disclosure, the method may further include a step of increasing the pressure of the feed liquid, for example, before step S1, increasing the pressure of the saline wastewater after increasing the pressure to 0.3-1.5MPa, and before step S3, increasing the pressure of the second pretreatment liquid after increasing the pressure to 1.0-4.5MPa, which is a common technical means in the art and will not be described herein again.
According to the present disclosure, in step S5, the concentration process may include a reverse osmosis concentration process in order to obtain a further concentrated sodium chloride brine.
The composition and concentration of the saline wastewater treated according to the present disclosure is not particularly limited, for example, the saline wastewater may be high-salinity wastewater, and in one specific embodiment, the pH of the saline wastewater may be 6-11, the TDS content may be 2000-45000mg/L, and the SO content may be 45000mg/L4 2-The concentration can be 1000-25000mg/L, Cl-The concentration can be 500-10000mg/L, the COD can be 200-2500mg/L, the total hardness can be 0-500mg/L, SiO2The concentration can be 0-100mg/L, CO3 2-The concentration may be 0-100 mg/L.
According to the present disclosure, the salt-containing wastewater may be pretreated to primarily remove impurities such as floating oil, organic matters, heavy metal ions and the like with large particle size, for example, in step S1, the first pretreatment may include at least one of solid-liquid separation, oxidation, ion exchange and filtration steps to primarily filter impurities in the salt-containing wastewater to obtain primary purificationIn a specific embodiment, the pH value of the obtained first pretreatment solution can be 6-10, the TDS content can be 3500-4 2-The concentration can be 1000-30000mg/L, Cl-The concentration can be 500-12000mg/L, the COD can be 30-2000mg/L, the total hardness can be 0-450mg/L, SiO2The concentration can be 0-80mg/L, CO3 2-The concentration may be 0-50mg/L, in a preferred embodiment, the pH of the first pretreatment solution may be 7-9, the TDS content may be 5000-4 2-The concentration can be 3000-25000mg/L, Cl-The concentration can be 2500-10000mg/L, the COD can be 100-1000mg/L, the total hardness can be 20-300mg/L, SiO2The concentration can be 10-60mg/L, CO3 2-The concentration can be 5-40 mg/L.
According to the present disclosure, in step S2, the second pretreatment may include at least one of softening, oxidizing, decarbonizing, and filtering steps to remove SiO in the feed solution2、CO3 2-In a specific embodiment, the pH of the obtained second pretreatment solution can be 5-9, the TDS content can be 4000-85000mg/L, and the SO content can be4 2-The concentration can be 1500--The concentration can be 800-25000mg/L, the COD can be 20-300mg/L, the total hardness can be 0-20mg/L, SiO2The concentration can be 0-30mg/L, CO3 2-The concentration may be 0-5mg/L, in a preferred embodiment, the pH of the second pretreatment solution may be 7-9, the TDS content may be 6000-65000mg/L, SO4 2-The concentration can be 2000-40000mg/L, Cl-The concentration can be 1500-20000mg/L, the COD can be 35-250mg/L, the total hardness can be 0-16mg/L, SiO2The concentration can be 4-25mg/L, CO3 2-The concentration may be 1-4.5 mg/L. The first recovery liquid and the second recovery liquid are recovered in the processing procedures of the steps S1 and S2 in a certain proportion, so that the subsequent load of the system is reduced, and the energy consumption is obviously reduced.
The resulting sodium sulfate crystalline salts, sodium chloride crystalline salts, and miscellaneous salts may be dried according to the present disclosure for further use, for example, in one embodiment, the method may further comprise: step S8, drying the sodium sulfate crystalline salt, the sodium chloride crystalline salt and the miscellaneous salt respectively, and centrifugally drying the final mother liquor; or, the sodium sulfate crystal salt and the sodium chloride crystal salt are dried separately, and the mixed salt and the final mother liquor are dried together.
As shown in fig. 1, a second aspect of the present disclosure provides a system for treating salt-containing wastewater, which may include a raw water tank 101 of salt-containing wastewater, a first pretreatment unit 102, a second pretreatment unit 103, a reuse water tank 104, a nanofiltration treatment unit 201, a sodium sulfate crystallization unit 301, a concentration unit 302, a sodium chloride crystallization unit 303, and a miscellaneous salt treatment unit 401;
the outlet of the saline wastewater raw water tank 101 is communicated with the inlet of the first pretreatment unit 102, the pretreatment liquid outlet of the first pretreatment unit 102 communicates with the inlet of the second pretreatment unit 103, the pretreatment liquid outlet of the second pretreatment unit 103 is communicated with the inlet of the nanofiltration treatment unit 201, the nanofiltration treatment unit 201 comprises a nanofiltration concentrated water outlet and a nanofiltration water outlet, the nanofiltration concentrated water outlet is communicated with the inlet of the sodium sulfate crystallization unit 301, an outlet of the discharged mother liquor of the sodium sulfate crystallization unit 301 is communicated with an inlet of the miscellaneous salt treatment unit 401, the nanofiltration water outlet is communicated with the inlet of the concentration unit 302, the concentrated water outlet of the concentration unit 302 is communicated with the inlet of the sodium chloride crystallization unit 303, an outlet of the discharged mother liquor of the sodium chloride crystallization unit 303 is communicated with an inlet of the miscellaneous salt treatment unit 401; an inlet of the reuse water tank is respectively communicated with a recovered liquid outlet of the first pretreatment unit 102, a recovered liquid outlet of the second pretreatment unit 103, a recovered liquid outlet of the sodium sulfate crystallization unit 301, a recovered liquid outlet of the concentration unit 302 and a recovered liquid outlet of the sodium chloride crystallization unit 303.
According to one embodiment of the present disclosure, as shown in fig. 2, the first pretreatment unit 102 may include one or more of a homogenization conditioning tank 1021, a high-density clarifier 1022, an oxidation device 1023, a sand filter 1024, a submerged ultrafiltration device 1025, an ion exchange device 1026, and a reverse osmosis device 1027. The oxidizer 1023 may be an ozone catalytic oxidizer and/or aerated biological filter (BAF) as known in the art to remove organic matter from the water, and will not be described further herein.
According to an embodiment of the present disclosure, as shown in fig. 3, the second pretreatment unit 103 may include one or more of a raw material concentrate tank, a silicon and hardness removal device 1031, an advanced oxidation/COD removal device 1302, a decarbonization device 1303, and an ultrafiltration device 1304, which are known to those skilled in the art and will not be described herein.
In accordance with the present disclosure, the nanofiltration treatment unit 201 may include a nanofiltration membrane apparatus, and in a specific embodiment, the nanofiltration membrane apparatus may be a polar nanofiltration membrane apparatus, the number of stages of the nanofiltration membrane apparatus is 1 to 5, and preferably 2 to 3, so as to effectively intercept molecules having a relative molecular weight of more than 200 and efficiently permeate most of sodium chloride and sodium sulfate, and the operating pressure of the nanofiltration membrane may be varied within a certain range, for example, the operating pressure of the nanofiltration membrane may be 0.4 to 3.5MPa, and preferably 0.8 to 2.0 MPa.
According to the present disclosure, the sodium sulfate crystallization unit 301 may include a crystallization device commonly used in the art, for example, the sodium sulfate crystallization unit 301 may include one or more of a freezing crystallization device, a multi-effect vacuum evaporation crystallization device, an MVR evaporation crystallization device, and a falling film evaporation crystallization device, and the sodium sulfate crystallization unit 301 is preferably a multi-effect vacuum evaporation crystallization device and/or an MVR evaporation crystallization device in order to further save energy consumption and improve crystallization effect.
In accordance with the present disclosure, the concentration unit 302 may include a concentration device commonly found in the art, for example, the concentration unit 302 may include at least one of a reverse osmosis device, an electrodialysis device, and a forward osmosis device, and in a preferred embodiment, the concentration unit 302 may include a reverse osmosis device, and the operating pressure may be 0.45-4.0MPa, preferably 0.6-2.5 MPa.
According to the present disclosure, the sodium chloride crystallization unit 303 may include a crystallization device commonly known in the art, for example, the sodium chloride crystallization unit 303 may include one or more of a multi-effect vacuum evaporation crystallization device, an MVR evaporation crystallization device, and a falling film evaporation crystallization device, preferably a multi-effect vacuum evaporation crystallization device and/or an MVR evaporation crystallization device.
According to the present disclosure, the miscellaneous salt treatment unit 401 may include a crystallization apparatus commonly known in the art, for example, the miscellaneous salt treatment unit 401 may include one or more of a multi-effect vacuum evaporation crystallization apparatus, an MVR evaporation crystallization apparatus, and a falling film evaporation crystallization apparatus, preferably a multi-effect vacuum evaporation crystallization apparatus and/or an MVR evaporation crystallization apparatus.
According to the present disclosure, the system of the present disclosure may further include a packaging unit 501, and the packaging unit 501 may include a drying device and a packaging device commonly known in the art, for example, the packaging unit 501 may include a centrifuge, a dryer, a packaging machine, and the like commonly known in the art, and in a specific embodiment, the sodium sulfate crystalline salt and the sodium chloride crystalline salt may be dried by using an entrained flow dryer, and the miscellaneous salt may be dried by using a rake dryer, which is not described in detail herein.
The following examples are provided to further illustrate the present invention, but the present invention is not limited thereto in any way.
Example 1
The system for treating salt-containing wastewater of the embodiment is shown in fig. 1, fig. 2 and fig. 3, and comprises a raw water tank 101 for salt-containing wastewater, a first pretreatment unit 102, a second pretreatment unit 103, a reuse water tank 104, a nanofiltration treatment unit 201, a sodium sulfate crystallization unit 301, a concentration unit 302, a sodium chloride crystallization unit 303, a mixed salt treatment unit 401 and a packaging unit 501; the first pretreatment unit 102 comprises a homogenization tank 1021, a high-density clarifier 1022, an oxidation device 1023, a sand filter 1024, an immersed ultrafiltration device 1025, an ion exchange device 1026 and a reverse osmosis device 1027; the second pretreatment unit 103 includes a silicon and hardness removal device 1031, an advanced oxidation/COD removal device 1032, a decarbonization tower 1033, and an ultrafiltration device 1034.
The method comprises the steps of boosting the pressure of raw material salt-containing wastewater to 0.4MPa, sequentially entering a raw water tank 101 and a homogenization treatment tank 1021 for the salt-containing wastewater to remove possible floating oil, colloid substances and partial suspended substances in the salt-containing wastewater, sending the treated feed liquid into a high-density clarification tank 1022 to remove sludge in the water and soften the sludge to obtain clarified liquid and reflux liquid containing a small amount of sludge, sending the reflux liquid part containing the small amount of sludge at the lower part of the high-density clarification tank 1022 back to the homogenization treatment tank 1021 for homogenization treatment, dewatering and drying the rest sludge, sending the clarified liquid at the upper part into an oxidation device 1023, namely an ozone catalytic oxidation device and an aeration biological filter to remove partial SS, COD and BOD, sequentially entering a sand filter 1024 and an immersed ultrafiltration device 1025 for filtration and purification to remove the suspended substances and intercept a part of macromolecular organic matters, and sequentially entering an ion exchange device 1026 and a reverse osmosis device 1027 for further concentration to obtain a first water quality target-meeting the water The method comprises the steps of feeding a pretreatment liquid and a first recovery liquid, feeding the first recovery liquid into a reuse water tank 104 to be recovered, boosting the pressure of the first pretreatment liquid to 0.85MPa, sequentially feeding the first pretreatment liquid into a silicon and hard removal device 1031, an advanced oxidation/COD removal device 1032, a decarbonization tower 1033 and an ultrafiltration device 1034, feeding a second recovery liquid obtained from the ultrafiltration device 1034 into the reuse water tank 104, boosting the pressure of the second pretreatment liquid to 1.5MPa, feeding the second pretreatment liquid into a nanofiltration device 201 to be subjected to nanofiltration separation treatment to obtain nanofiltration concentrated water and nanofiltration product water, feeding the nanofiltration concentrated water into a sodium sulfate crystallization unit 301 to be subjected to multiple-effect vacuum evaporation crystallization treatment to obtain sodium sulfate crystal salt, a third recovery liquid and a first discharged mother liquid, feeding the nanofiltration product water into a concentration unit 302 to be subjected to concentration treatment and a sodium chloride crystallization unit 303 to be subjected to multiple-effect vacuum evaporation crystallization treatment to obtain sodium chloride crystal salt, a fourth recovery liquid and a second discharged, and (3) sending the third recovery solution and the fourth recovery solution into a reuse water tank 104, respectively sending the first outer row mother solution and the second outer row mother solution into a mixed salt treatment unit 401 for mixing, then carrying out mixed salt treatment, carrying out multiple-effect vacuum evaporation crystallization to obtain mixed salt and final mother solution, respectively drying the sodium sulfate crystal salt and the sodium chloride crystal salt, carrying out centrifugal drying treatment on the mixed salt and the final mother solution, and sending the mixed salt and the final mother solution into a packaging unit 501 for packaging to obtain a final product.
The results of the measurements on a part of the samples in this example:
salt-containing wastewater: pH 7, TDS content 11000mg/L, SO4 2-Concentration 4000mg/L, Cl-The concentration is 1000mg/L, the COD is 500mg/L, the total hardness is 350mg/L, and the SiO content is2Concentration of 60mg/L, CO3 2-The concentration was 30 mg/L.
First pretreatment liquid: pH 7, TDS content 41000mg/L, SO4 2-Concentration of 20000mg/L, Cl-The concentration is 5000mg/L, the COD is 80mg/L, the total hardness is 10mg/L, and the SiO content is2Concentration of 10mg/L, CO3 2-The concentration was 0 mg/L.
A second pretreatment liquid: pH 7, TDS content 45000mg/L, SO4 2-Concentration 41000mg/L, Cl-The concentration is 2000mg/L, the COD is 50mg/L, the total hardness is 10mg/L, and the SiO content is2Concentration of 0mg/L, CO3 2-The concentration was 0 mg/L.
Sodium sulfate crystalline salt: 99.1% of sodium sulfate, 0.03% of water-insoluble matter and 0.34% of chloride.
Crystalline sodium chloride salt: the content of sodium chloride is 98.7 percent, and the content of sulfate radical is 0.45 percent.
Reuse water: the pH value is 7.2, the TDS content is 450mg/L, and the COD is 30 mg/L.
The content of miscellaneous salts in the embodiment accounts for 3.5% of the total content of crystal salts, and the detection shows that the salt does not contain heavy metal ions, and the salt can be used as general solid waste for treatment, and the parameters of the final product in the embodiment are listed in table 1.
Example 2
The system and method for treating salt-containing wastewater of this example are the same as those of example 1, except that the raw salt-containing wastewater of this example is different from that of example 1.
The results of the measurements on a part of the samples in this example:
the pH value of the salt-containing wastewater in the embodiment is 7, the TDS content is 30000mg/L, and SO is4 2-Concentration 18000mg/L, Cl-The concentration is 1500mg/L, the COD is 1200mg/L, the total hardness is 400mg/L, and SiO is2Concentration 50mg/L, CO3 2-The concentration was 40 mg/L.
First pretreatment liquid: pH 7.5, TDS content 31500mg/L, SO4 2-Concentration 19000mg/L, Cl-The concentration is 1500mg/L, the COD is 1050mg/L, the total hardness is 300mg/L, and SiO2Concentration of 45mg/L, CO3 2-The concentration was 38 mg/L.
A second pretreatment liquid: pH value of 8, TDS content of 33000mg/L, SO4 2-Concentration 19500mg/L, Cl-The concentration is 1700mg/L, the COD is 8mg/L, the total hardness is 10mg/L, and the SiO content is2Concentration of 20mg/L, CO3 2-The concentration was 3 mg/L.
Sodium sulfate crystalline salt: sodium sulfate content 98.5%, water insoluble content 0.42%, chloride content 0.5%.
Crystalline sodium chloride salt: the content of sodium chloride is 97.8 percent, and the content of sulfate radical is 0.72 percent.
Reuse water: the pH value is 7.1, the TDS content is 650mg/L, and the COD is 37 mg/L.
The content of miscellaneous salts in the present example accounts for 7.5% of the total content of crystal salts, and the detection shows that the salt does not contain heavy metal ions, and the salt can be used as general solid waste treatment, and the final product parameters of the present example are listed in table 1.
Comparative example
The raw material salt-containing wastewater of the comparative example is the same as that of example 1, the raw material salt-containing wastewater is used as raw water, nanofiltration treatment is performed on the raw water, concentrated water subjected to nanofiltration treatment is subjected to evaporative crystallization treatment to obtain anhydrous sodium sulfate, water produced by nanofiltration treatment is subjected to secondary nanofiltration treatment, the concentrated water subjected to secondary nanofiltration treatment is subjected to evaporative crystallization to obtain anhydrous sodium sulfate when the chloride ion concentration of the concentrated water subjected to secondary nanofiltration treatment is less than a specified value, the concentrated water subjected to secondary nanofiltration treatment is added into the next raw water to be subjected to nanofiltration treatment again with the next raw water when the chloride ion concentration of the concentrated water subjected to secondary nanofiltration treatment is not less than the specified value, water produced by secondary nanofiltration treatment is subjected to reverse osmosis treatment, the reverse osmosis concentrated water is subjected to evaporative crystallization to sodium oxide to obtain sodium oxide. Wherein, whether the water produced from the water outlet of the nanofiltration equipment flows out or not is adopted for judging the dilution process, and when the water produced from the water outlet of the nanofiltration equipment flows out in a dripping manner, the nanofiltration treatment can be stopped.
Wherein, the process for the evaporation crystallization treatment of the anhydrous sodium sulfate comprises the following steps: the evaporation temperature is 135 ℃ under normal pressure, when a specified amount of anhydrous sodium sulfate solid is separated out, the temperature is reduced to 50-55 ℃, the temperature is kept for 2 hours, and then filtration is carried out; the evaporative crystallization treatment process for sodium chloride comprises the following steps: the evaporation temperature is 135 ℃ under normal pressure, and filtration is carried out when a specified amount of sodium chloride solid is precipitated. The final product parameters for this comparative example are listed in table 1.
TABLE 1
Item Example 1 Example 2 Comparative example
Quality of sodium sulfate Class I first-class products Class I first-class products Class III certified products
Quality of sodium chloride Industrial dry salt first grade Industrial dry salt first grade Industrial wet salt third stage
Sodium sulfate yield% 95 92 89
Yield of sodium chloride,% 93 90 68
Water reuse rate% 81 77 65
TDS, mg/L of reuse water 450 650 2000
Reuse water COD, mg/L 30 37 500
The salt content, dry basis,%, 3.5 7.5 20
as can be seen from table 1, when the method and system of the present disclosure are used to treat salt-containing wastewater, not only can the sodium sulfate crystalline salt, the sodium chloride crystalline salt and the reuse water meeting the industrial standards be directly recovered, but also the recovery rate is significantly improved, and compared with the method and system of comparative example 1, the energy consumption for treating single volume of salt-containing wastewater by the method and system of example 1 is reduced by 10%, and the economic benefit is also significantly improved.
The preferred embodiments of the present disclosure are described in detail with reference to the accompanying drawings, however, the present disclosure is not limited to the specific details of the above embodiments, and various simple modifications may be made to the technical solution of the present disclosure within the technical idea of the present disclosure, and these simple modifications all belong to the protection scope of the present disclosure.
It should be noted that the various technical features described in the above embodiments may be combined in any suitable manner without contradiction, and the disclosure does not separately describe various possible combinations in order to avoid unnecessary repetition.
In addition, any combination of various embodiments of the present disclosure may be made, and the same should be considered as the disclosure of the present disclosure, as long as it does not depart from the spirit of the present disclosure.

Claims (10)

1. A method for treating salt-containing wastewater, which is characterized by comprising the following steps:
s1, carrying out first pretreatment on the salt-containing wastewater to obtain a first pretreatment solution and a first recovery solution;
s2, carrying out second pretreatment on the first pretreatment solution to obtain a second pretreatment solution and a second recovery solution;
s3, performing nanofiltration separation treatment on the second pretreatment solution to obtain nanofiltration concentrated water and nanofiltration produced water;
s4, carrying out sodium sulfate crystallization treatment on the nanofiltration concentrated water to obtain sodium sulfate crystalline salt, a third recovery liquid and a first discharged mother liquid;
s5, concentrating the nanofiltration water and crystallizing sodium chloride to obtain sodium chloride crystal salt, a fourth recovery liquid and a second external mother liquid;
s6, mixing the first discharged mother liquor and the second discharged mother liquor, and then carrying out mixed salt treatment to obtain mixed salt and final mother liquor;
and S7, mixing the first recovery liquid, the second recovery liquid, the third recovery liquid and the fourth recovery liquid to obtain reuse water, wherein the TDS content of the reuse water is 0-1000mg/L, and the COD is 0-50 mg/L.
2. The method of claim 1, wherein the method further comprises: before step S1, boosting the pressure of the salt-containing wastewater, wherein the pressure of the boosted salt-containing wastewater is 0.3-1.5 MPa; and/or the like and/or,
before step S3, the pressure of the second pretreatment liquid is increased, and the pressure of the second pretreatment liquid after the pressure increase is 1.0 to 4.5 MPa.
3. The method of claim 1, wherein in step S5, the concentration process comprises a reverse osmosis concentration process.
4. The method as claimed in claim 1, wherein the pH value of the saline wastewater is 6-11, the TDS content is 2000-45000mg/L, and SO content is 45000mg/L4 2-The concentration is 1000-25000mg/L, Cl-The concentration is 500-10000mg/L, the COD is 200-2500mg/L, the total hardness is 0-500mg/L, SiO2Concentration of 0-100mg/L, CO3 2-The concentration is 0-100 mg/L.
5. The method as claimed in claim 1, wherein in step S1, the first pretreatment comprises at least one of solid-liquid separation, oxidation, ion exchange and filtration steps, and the pH value of the obtained first pretreatment solution is 6-10, the TDS content is 3500 and 45000mg/L, and the SO content is 3500 and 45000mg/L4 2-Concentration of 1000-30000mg/L, Cl-The concentration is 500-12000mg/L, the COD is 30-2000mg/L, the total hardness is 0-450mg/L, SiO2Concentration of 0-80mg/L, CO3 2-The concentration is 0-50 mg/L; and/or the like and/or,
in step S2, the second pretreatment step includes at least one of softening, oxidizing, decarbonizing and filtering steps, the pH value of the obtained second pretreatment solution is 5-9, the TDS content is 4000-4 2-The concentration is 1500--The concentration is 800-25000mg/L, the COD is 20-300mg/L, the total hardness is 0-20mg/L, SiO2Concentration of 0-30mg/L, CO3 2-The concentration is 0-5 mg/L.
6. The method of any of claims 1-5, wherein the method further comprises: step S8, drying the sodium sulfate crystalline salt, the sodium chloride crystalline salt and the miscellaneous salt respectively, and carrying out centrifugal drying treatment on the final mother liquor; alternatively, the first and second electrodes may be,
and respectively drying the sodium sulfate crystal salt and the sodium chloride crystal salt, and drying the mixed salt and the final mother liquor.
7. A system for treating salt-containing wastewater is characterized by comprising a salt-containing wastewater raw water tank (101), a first pretreatment unit (102), a second pretreatment unit (103), a reuse water tank (104), a nanofiltration treatment unit (201), a sodium sulfate crystallization unit (301), a concentration unit (302), a sodium chloride crystallization unit (303) and a mixed salt treatment unit (401);
the outlet of the raw water tank (101) containing salt wastewater is communicated with the inlet of the first pretreatment unit (102), the pretreatment liquid outlet of the first pretreatment unit (102) is communicated with the inlet of the second pretreatment unit (103), the pretreatment liquid outlet of the second pretreatment unit (103) is communicated with the inlet of the nanofiltration treatment unit (201), the nanofiltration treatment unit (201) comprises a nanofiltration concentrated water outlet and a nanofiltration water outlet, the nanofiltration concentrated water outlet is communicated with the inlet of the sodium sulfate crystallization unit (301), the effluent mother liquid outlet of the sodium sulfate crystallization unit (301) is communicated with the inlet of the miscellaneous salt treatment unit (401), the nanofiltration water outlet is communicated with the inlet of the concentration unit (302), and the concentrated water outlet of the concentration unit (302) is communicated with the inlet of the sodium chloride crystallization unit (303), an outlet of the discharged mother liquor of the sodium chloride crystallization unit (303) is communicated with an inlet of the mixed salt treatment unit (401),
an inlet of the reuse water tank (104) is respectively communicated with a recovered liquid outlet of the first pretreatment unit (102), a recovered liquid outlet of the second pretreatment unit (103), a recovered liquid outlet of the sodium sulfate crystallization unit (301), a recovered liquid outlet of the concentration unit (302) and a recovered liquid outlet of the sodium chloride crystallization unit (303).
8. The system of claim 7, wherein the first pretreatment unit (102) comprises one or more of a homogenization conditioning tank, a high density clarifier, an ozone catalytic oxidation unit, a biological aerated filter, a sand filter, an immersed ultrafiltration unit, an ion exchange unit, and a reverse osmosis unit; and/or the like and/or,
the second pretreatment unit (103) comprises one or more of a raw material concentrated water tank, a silicon and hardness removal device, an advanced oxidation/COD removal device, a decarburization device and an ultrafiltration device.
9. The system of claim 7, wherein the nanofiltration treatment unit (201) comprises a nanofiltration membrane apparatus having a number of stages of 1-5, preferably 2-3.
10. The system according to claim 7, wherein the sodium sulfate crystallization unit (301) comprises one or more of a freeze crystallization device, a multi-effect vacuum evaporation crystallization device, a MVR evaporation crystallization device, and a falling film evaporation crystallization device, preferably a multi-effect vacuum evaporation crystallization device and/or a MVR evaporation crystallization device; and/or the like and/or,
the concentration unit (302) comprises at least one of a reverse osmosis device, an electrodialysis device and a forward osmosis device, preferably a reverse osmosis device; and/or the like and/or,
the sodium chloride crystallization unit (303) comprises one or more of a multi-effect vacuum evaporation crystallization device, an MVR evaporation crystallization device and a falling film evaporation crystallization device, and preferably comprises the multi-effect vacuum evaporation crystallization device and/or the MVR evaporation crystallization device; and/or the like and/or,
the mixed salt treatment unit (401) comprises one or more of a multi-effect vacuum evaporation crystallization device, an MVR evaporation crystallization device and a falling film evaporation crystallization device, and preferably comprises the multi-effect vacuum evaporation crystallization device and/or the MVR evaporation crystallization device.
CN202010006094.9A 2020-01-03 2020-01-03 Method and system for treating salt-containing wastewater Pending CN113072228A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202010006094.9A CN113072228A (en) 2020-01-03 2020-01-03 Method and system for treating salt-containing wastewater

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202010006094.9A CN113072228A (en) 2020-01-03 2020-01-03 Method and system for treating salt-containing wastewater

Publications (1)

Publication Number Publication Date
CN113072228A true CN113072228A (en) 2021-07-06

Family

ID=76608631

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202010006094.9A Pending CN113072228A (en) 2020-01-03 2020-01-03 Method and system for treating salt-containing wastewater

Country Status (1)

Country Link
CN (1) CN113072228A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113912231A (en) * 2021-07-13 2022-01-11 北京航天环境工程有限公司 System and method for recycling and co-processing wastewater
CN115448333A (en) * 2022-09-09 2022-12-09 鲁维制药集团有限公司 High-salt wastewater co-production recovery process in vitamin C production process

Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20140227151A1 (en) * 2013-02-14 2014-08-14 Board Of Regents, The University Of Texas System Recovery and purification of monovalent salt contaminated with divalent salt
WO2017181696A1 (en) * 2016-04-21 2017-10-26 广州市心德实业有限公司 Method for treating and recycling brine wastewater containing sodium chloride and sodium sulfate
US20180029904A1 (en) * 2016-07-28 2018-02-01 Veolia Water Technologies, Inc. Enhanced process for selective salt recovery from wastewater, waste salts, and brines
US20180148350A1 (en) * 2016-11-29 2018-05-31 China Petroleum & Chemical Corporation Method and System for Treating Brine Waste Water
CN108623104A (en) * 2018-07-16 2018-10-09 南京工业大学 A kind of high-salinity wastewater zero-emission processing method and processing device based on NF membrane allotment
CN209276303U (en) * 2018-12-05 2019-08-20 内蒙古荣信化工有限公司 Coal water slurry gasification waste water divides salt to crystallize zero-discharge treatment system
CN110342545A (en) * 2019-01-24 2019-10-18 内蒙古晶泰环境科技有限责任公司 High-salt wastewater divides salt system and its technique
CN209507610U (en) * 2019-01-24 2019-10-18 内蒙古晶泰环境科技有限责任公司 High-salt wastewater divides salt system
CN110357334A (en) * 2018-12-05 2019-10-22 内蒙古荣信化工有限公司 Coal water slurry gasification waste water divides salt crystallization zero-discharge treatment system and method
CN110615451A (en) * 2019-10-21 2019-12-27 博天环境集团股份有限公司 Method and system for recycling and harmlessly treating salt in high-salt-content wastewater

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20140227151A1 (en) * 2013-02-14 2014-08-14 Board Of Regents, The University Of Texas System Recovery and purification of monovalent salt contaminated with divalent salt
WO2017181696A1 (en) * 2016-04-21 2017-10-26 广州市心德实业有限公司 Method for treating and recycling brine wastewater containing sodium chloride and sodium sulfate
US20180029904A1 (en) * 2016-07-28 2018-02-01 Veolia Water Technologies, Inc. Enhanced process for selective salt recovery from wastewater, waste salts, and brines
US20180148350A1 (en) * 2016-11-29 2018-05-31 China Petroleum & Chemical Corporation Method and System for Treating Brine Waste Water
CN108623104A (en) * 2018-07-16 2018-10-09 南京工业大学 A kind of high-salinity wastewater zero-emission processing method and processing device based on NF membrane allotment
CN209276303U (en) * 2018-12-05 2019-08-20 内蒙古荣信化工有限公司 Coal water slurry gasification waste water divides salt to crystallize zero-discharge treatment system
CN110357334A (en) * 2018-12-05 2019-10-22 内蒙古荣信化工有限公司 Coal water slurry gasification waste water divides salt crystallization zero-discharge treatment system and method
CN110342545A (en) * 2019-01-24 2019-10-18 内蒙古晶泰环境科技有限责任公司 High-salt wastewater divides salt system and its technique
CN209507610U (en) * 2019-01-24 2019-10-18 内蒙古晶泰环境科技有限责任公司 High-salt wastewater divides salt system
CN110615451A (en) * 2019-10-21 2019-12-27 博天环境集团股份有限公司 Method and system for recycling and harmlessly treating salt in high-salt-content wastewater

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113912231A (en) * 2021-07-13 2022-01-11 北京航天环境工程有限公司 System and method for recycling and co-processing wastewater
CN113912231B (en) * 2021-07-13 2023-09-26 北京航天环境工程有限公司 System and method for resource co-processing of wastewater
CN115448333A (en) * 2022-09-09 2022-12-09 鲁维制药集团有限公司 High-salt wastewater co-production recovery process in vitamin C production process

Similar Documents

Publication Publication Date Title
CN105540967B (en) A kind of organic wastewater minimizing, recycling processing method and processing system
JP2018086649A (en) Method and system for treatment of brine waste water
CN105439395A (en) Zero-discharge treatment method of salt-containing organic wastewater
US20110062079A1 (en) Process for treating water by a nanofiltration or reverse osmosis membrane system enabling high conversion rates due to the elimination of organic matter
CN106116011B (en) A kind of coal chemical wastewater treating technique
CN108117222B (en) Zero-discharge treatment method for salt-containing wastewater in coal chemical industry
CN105016577A (en) Advanced treatment system for process sewage and advanced treatment method for sewage
CN101381190A (en) Treatment technique suitable for high salt and high concentrated organic wastewater
CN102897944A (en) System for deeply processing difficultly degradable organic waste water
CN111362283A (en) Viscose waste water recycling treatment method
CN110683716A (en) Wastewater treatment process for wastewater generated by automobile accessory coating production line
CN111056653A (en) Cold rolling wastewater treatment system and method
CN104058525B (en) Production waste recovery and treatment method containing high ammonia nitrogen and nitric nitrogen
CN111661979B (en) Leachate recycling method and device
CN113072228A (en) Method and system for treating salt-containing wastewater
CN112047553A (en) PTA high-salinity wastewater treatment, reuse and zero-discharge system and method
CN111875180A (en) Coal chemical industry wastewater zero-discharge integrated treatment system and method
CN110627290A (en) High salt waste water resourceful treatment system
CN211664826U (en) System for handle high salt waste water
CN108117223B (en) Zero-discharge treatment method for salt-containing wastewater
CN212924710U (en) Industrial wastewater zero discharge treatment system
CN109354348A (en) The integrated processing method of vitamin B12 production waste water
CN105836954A (en) System and method for efficient and energy-saving treatment of salt-containing wastewater
CN110342740B (en) Method and system for purifying organic wastewater containing salt
CN112093945A (en) Method for degrading organic wastewater

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
RJ01 Rejection of invention patent application after publication
RJ01 Rejection of invention patent application after publication

Application publication date: 20210706